阅读说明：本技术 热转印打印机和印刷控制方法 (Thermal transfer printer and printing control method ) 是由 冲中潮广 于 2017-07-05 设计创作，主要内容包括：热转印打印机(100)进行在纸张(7)上形成端部(Gae)和端部(Gbe)的灰度控制处理。在灰度控制处理中,进行热处理Ha和热处理Hb。在热处理Ha中,按照端部(Gae)的后端(Gae2)侧的墨片(6)产生的显色的轮廓与主扫描方向平行地对齐的方式使热敏头(9)发出热。在热处理Hb中,按照端部(Gbe)的前端(Gbe1)侧的墨片(6)产生的显色的轮廓与上述主扫描方向平行地对齐的方式使热敏头(9)发出热。(A thermal transfer printer (100) performs gradation control processing for forming an end portion (Gae) and an end portion (Gbe) on a sheet (7). In the gradation control process, the heat treatment Ha and the heat treatment Hb are performed. In the heat treatment Ha, the thermal head (9) is heated so that the color development profile of the ink sheet (6) on the rear end (Gae2) side of the end portion (Gae) is aligned in parallel with the main scanning direction. In the heat treatment Hb, the thermal head (9) is heated so that the color development profile of the ink sheet (6) on the leading end (Gbe1) side of the end portion (Gbe) is aligned in parallel with the main scanning direction.)

1. A thermal transfer printer in which an ink sheet (6) is heated by a thermal head (9) to form a composite image (Gw) represented by a 1 st image (Gwa) and a 2 nd image (Gwb) on a paper sheet (7),

the composite image (Gw) has an overlapping region (Rw) in which a 2 nd edge (Gbe) that is a front edge of the 2 nd image (Gwb) is overlapped with a 1 st edge (Gae) that is a rear edge of the 1 st image (Gwa),

the 1 st end portion (Gae) has a 1 st leading end (Gae1) corresponding to a leading end of the overlap region (Rw) and a 1 st trailing end (Gae2) which is a trailing end of the 1 st image (Gwa),

the 2 nd edge part (Gbe) has a 2 nd leading edge (Gbe1) which is the leading edge of the 2 nd image (Gwb) and a 2 nd trailing edge (Gbe2) which corresponds to the trailing edge of the overlap region (Rw),

the thermal transfer printer is provided with the thermal head (9) which emits heat,

the thermal transfer printer performs a gradation control process of forming the 1 st end portion (Gae) and the 2 nd end portion (Gbe) on the paper sheet (7),

in the gradation control process, the 1 st heat treatment and the 2 nd heat treatment are performed,

in the 1 st heat treatment, the thermal head (9) is heated so that the concentration of the 1 st end portion (Gae) gradually decreases from the 1 st leading end (Gae1) to the 1 st trailing end (Gae2) and a color development profile of the ink sheet (6) on the 1 st trailing end (Gae2) side of the 1 st end portion (Gae) is aligned in parallel with a main scanning direction,

in the 2 nd heat treatment, the thermal head (9) is caused to emit heat such that the density of the 2 nd end portion (Gbe) gradually increases from the 2 nd leading end (Gbe1) toward the 2 nd trailing end (Gbe2), and a color development profile of the ink sheet (6) on the 2 nd leading end (Gbe1) side of the 2 nd end portion (Gbe) is aligned in parallel with the main scanning direction.

2. The thermal transfer printer according to claim 1, wherein the 1 st heat treatment is a treatment of forming the 1 st end portion (Gae) on the paper (7), the 1 st end portion (Gae) being generated using a coefficient calculated using a correction value obtained based on a position in a sub-scanning direction of the overlap region (Rw) and heat energy emitted by the thermal head (9),

the 2 nd heat treatment is a treatment of forming the 2 nd end portion (Gbe) generated by the coefficient on the paper sheet (7).

3. The thermal transfer printer according to claim 1 or 2, wherein in the 1 st heat treatment and the 2 nd heat treatment, the thermal head (9) is further caused to emit heat in such a manner that a tone of a halftone of the 1 st end portion (Gae) is the same as a tone of a halftone of the 2 nd end portion (Gbe).

4. A printing control method performed by a thermal transfer printer which forms a composite image (Gw) represented by a 1 st image (Gwa) and a 2 nd image (Gwb) on a sheet (7) by heating an ink sheet (6) with a thermal head (9),

the composite image (Gw) has an overlapping region (Rw) in which a 2 nd edge (Gbe) that is a front edge of the 2 nd image (Gwb) is overlapped with a 1 st edge (Gae) that is a rear edge of the 1 st image (Gwa),

the 1 st end portion (Gae) has a 1 st leading end (Gae1) corresponding to a leading end of the overlap region (Rw) and a 1 st trailing end (Gae2) which is a trailing end of the 1 st image (Gwa),

the 2 nd edge part (Gbe) has a 2 nd leading edge (Gbe1) which is the leading edge of the 2 nd image (Gwb) and a 2 nd trailing edge (Gbe2) which corresponds to the trailing edge of the overlap region (Rw),

the printing control method includes a gradation control step (S160, S160B) of forming the 1 st end portion (Gae) and the 2 nd end portion (Gbe) on the sheet (7),

in the gradation control step (S160, S160B), the 1 st heat treatment and the 2 nd heat treatment are performed,

in the 1 st heat treatment, the thermal head (9) is heated so that the concentration of the 1 st end portion (Gae) gradually decreases from the 1 st leading end (Gae1) to the 1 st trailing end (Gae2) and a color development profile of the ink sheet (6) on the 1 st trailing end (Gae2) side of the 1 st end portion (Gae) is aligned in parallel with a main scanning direction,

in the 2 nd heat treatment, the thermal head (9) is caused to emit heat such that the density of the 2 nd end portion (Gbe) gradually increases from the 2 nd leading end (Gbe1) toward the 2 nd trailing end (Gbe2), and a color development profile of the ink sheet (6) on the 2 nd leading end (Gbe1) side of the 2 nd end portion (Gbe) is aligned in parallel with the main scanning direction.

Technical Field

The present invention relates to a thermal transfer printer having a function of printing a long image using two or more images, and a print control method.

Background

In recent years, in thermal transfer printers, there are increasing scenes in which panoramic printing is performed in which a long image is printed using at least two images. To perform panoramic printing, first, two images are acquired from a long image, for example. Then, the two images are printed so that they are connected, thereby realizing panoramic printing. Patent documents 1 and 2 disclose the following techniques: the long image is printed by overlapping the front end portion of the second image on the rear end portion of the first image.

Patent document 1 discloses the following configuration: the overlapping region of the front end portion of the second image is overlapped with the rear end portion of the first image, and the boundary line of the two images is inconspicuous (hereinafter, also referred to as "related configuration a").

Specifically, in the related configuration a, the density of the rear end portion of the first image gradually decreases from the front end to the rear end of the rear end portion. In addition, the density of the front end portion of the second image gradually increases from the front end of the front end portion to the rear end. Thereby, the print density in the overlap region is adjusted. Printing refers to an image printed on paper. In addition, in the related configuration a, a technique of performing image processing by a dither method on the overlapping area is also disclosed.

Further, patent document 2 discloses a configuration (hereinafter, also referred to as "related configuration B") in which a color change in an overlapping region of two images is eliminated. Specifically, in the correlation configuration B, the color values of the overlapping area are converted using a color conversion coefficient group prepared in advance. Thereby, color variations in the overlapping area are reduced.

Disclosure of Invention

Problems to be solved by the invention

In the thermal transfer printer, the thermal energy given to the dye (ink) by the thermal head is different for each density of pixels of the image of the printing object. For example, the lower the concentration of the pixels, the less thermal energy is required. The smaller the thermal energy, the more easily the position on the paper where the pixel develops color deviates from the desired position.

Therefore, depending on the density type of 2 or more pixels constituting the outline of the image edge (overlap region), there is a possibility that the outline is displayed on the paper in a curved line. When this phenomenon occurs, there is a problem that the quality of a joint portion (overlapping region) of two images is degraded.

Therefore, regardless of the density of 2 or more pixels constituting the outline of the image edge, the outline is required to be displayed on the sheet in the form of a straight line along the main scanning direction. In the related configuration A, B, this requirement cannot be satisfied.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a thermal transfer printer or the like that can display an outline of an image edge on a sheet as a straight line along a main scanning direction regardless of the density of 2 or more pixels constituting the outline.

Means for solving the problems

In order to achieve the above object, a thermal transfer printer according to one embodiment of the present invention heats an ink sheet with a thermal head to form a composite image represented by a 1 st image and a 2 nd image on a sheet. The composite image has an overlap region in which a 2 nd end portion as a front end portion of the 2 nd image is overlapped at a 1 st end portion as a rear end portion of the 1 st image, the 1 st end portion has a 1 st front end corresponding to a front end of the overlap region and a 1 st rear end corresponding to a rear end of the 1 st image, the 2 nd end portion has a 2 nd front end corresponding to a front end of the 2 nd image and a 2 nd rear end corresponding to a rear end of the overlap region, the thermal transfer printer includes the thermal head that generates heat, the thermal transfer printer performs a gradation control process of forming the 1 st end portion and the 2 nd end portion on the sheet, the gradation control process performs a 1 st heat process and a 2 nd heat process, and the thermal head gradually decreases in density of the 1 st end portion from the 1 st front end portion toward the 1 st rear end portion in the 1 st heat process, And the thermal head emits heat so that a color development contour of the ink sheet on the 1 st rear end side of the 1 st end portion is aligned in parallel with a main scanning direction, and in the 2 nd heat treatment, the thermal head emits heat so that a density of the 2 nd end portion gradually increases from the 2 nd leading end toward the 2 nd rear end and a color development contour of the ink sheet on the 2 nd leading end side of the 2 nd end portion is aligned in parallel with the main scanning direction.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, in the 1 st heat treatment, the thermal head emits heat so that a color development contour of the ink sheet on the 1 st trailing end side of the 1 st end portion is aligned in parallel with the main scanning direction. That is, in the 1 st heat treatment, the thermal head emits heat so that the contour of the 1 st rear end side of the 1 st end portion is displayed on the sheet as a straight line along the main scanning direction.

In the 2 nd heat treatment, the thermal head emits heat so that a color development contour of the ink sheet on the 2 nd leading end side of the 2 nd end portion is aligned in parallel with the main scanning direction. That is, in the 2 nd heat treatment, the thermal head emits heat so that the contour of the 2 nd leading end side of the 2 nd end portion is displayed on the sheet as a straight line along the main scanning direction.

Thus, regardless of the density of 2 or more pixels constituting the outline of the image edge, it is possible to realize that the outline is displayed on the sheet in the form of a straight line along the main scanning direction.

The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

Drawings

Fig. 1 is a block diagram showing a main configuration of a thermal transfer printer according to embodiment 1 of the present invention.

Fig. 2 is a diagram mainly illustrating a configuration for performing printing in the thermal transfer printer according to embodiment 1 of the present invention.

Fig. 3 is a diagram for explaining an ink sheet.

Fig. 4 is a diagram for explaining panorama printing.

Fig. 5 is a flowchart of panorama printing processing according to embodiment 1 of the present invention.

Fig. 6 is a diagram showing an example of the correction table.

Fig. 7 is a diagram showing an example of another correction table.

Fig. 8 is a diagram for explaining a state where an image is printed.

Fig. 9 is a diagram for explaining a state where an image is printed.

Fig. 10 is a diagram for explaining characteristics regarding thermal energy.

Fig. 11 is a diagram for explaining characteristics regarding thermal energy.

Fig. 12 is a flowchart of panorama printing processing a according to embodiment 2 of the present invention.

Fig. 13 is a diagram for explaining adjustment of color tones.

Fig. 14 is a diagram showing lines used for adjustment of the density.

Fig. 15 is a flowchart of panorama printing processing B according to embodiment 3 of the present invention.

Fig. 16 is a diagram showing lines used for adjustment of the density.

Fig. 17 is a block diagram showing a characteristic functional configuration of the thermal transfer printer.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same reference numerals are attached to the same components. The names and functions of the components denoted by the same reference numerals are the same. Therefore, a detailed description of a part of each component element denoted by the same reference numeral may be omitted.

The dimensions, materials, shapes, relative arrangements of the respective constituent elements, and the like of the constituent elements exemplified in the embodiments may be appropriately changed according to the configuration of the apparatus to which the present invention is applied, various conditions, and the like.

< embodiment 1>

Fig. 1 is a block diagram showing a main configuration of a thermal transfer printer 100 according to embodiment 1 of the present invention. For the sake of explanation, fig. 1 also shows an information processing apparatus 200 that is not included in the thermal transfer printer 100. Hereinafter, printing an image on a sheet is also referred to as "printing". As described above, the print may be an image printed on a sheet. As will be described later in detail, the thermal transfer printer 100 performs a printing process P for printing an image on a sheet.

The information processing apparatus 200 is an apparatus that controls the thermal transfer printer 100. The information processing apparatus 200 is, for example, a PC (personal computer). The information processing apparatus 200 is operated by a user. When the user performs a print execution operation on the information processing apparatus 200, the information processing apparatus 200 transmits a print instruction and image data D1 to the thermal transfer printer 100. The print execution operation is an operation for causing the thermal transfer printer 100 to execute the print process P. The print instruction is an instruction for causing the thermal transfer printer 100 to execute the print process P. The image data D1 is data for an image to be printed on a sheet.

Fig. 2 is a diagram mainly illustrating a configuration for performing printing in the thermal transfer printer 100 according to embodiment 1 of the present invention. In fig. 1 and 2, components (e.g., power supplies) not relevant to the present invention are not shown. Fig. 2 shows a state in which the roll paper 7r and the ink sheet 6 are mounted on the thermal transfer printer 100. The roll paper 7r is formed by rolling up a long sheet of paper 7. The sheet 7 has a receiving layer.

The ink sheet 6 is a long sheet. The ink roller 6r is formed by rolling one end of the ink sheet 6 into a roll shape. The ink roller 6r is mounted on a reel 10a described later. The other end of the ink sheet 6 is rolled up in a roll shape to form an ink roller 6 rm. The ink roller 6rm is mounted on a spool 10b described later.

Fig. 3 is a diagram for explaining the ink sheet 6. In fig. 3, the X direction and the Y direction are orthogonal to each other. The X and Y directions shown in the lower figure are also orthogonal to each other. Hereinafter, a direction including the X direction and a direction opposite to the X direction (the (-X direction)) will also be referred to as an "X axis direction". Hereinafter, a direction including the Y direction and a direction opposite to the Y direction (the (-Y direction)) will also be referred to as "Y axis direction". Hereinafter, a plane including the X-axis direction and the Y-axis direction is also referred to as an "XY plane".

Referring to fig. 1, 2, and 3, the thermal transfer printer 100 includes a communication unit 2, a storage unit 3, a control unit 4, a conveying roller pair 5, a paper conveying unit 5M, a platen roller 8, a thermal head 9, and an ink sheet driving unit 10.

The communication unit 2 has a function of communicating with the information processing apparatus 200. The printing instruction and the image data D1 sent from the information processing apparatus 200 are sent to the control unit 4 via the communication unit 2.

The storage unit 3 is a memory for storing various data, programs, and the like. The storage unit 3 is composed of, for example, a volatile memory and a nonvolatile memory. Volatile memory is memory that temporarily stores data. The volatile memory is, for example, RAM. The nonvolatile memory stores a control program, initial setting values, and the like.

The control unit 4 performs various processes on each unit of the thermal transfer printer 100, as will be described in detail later. The control unit 4 controls the thermal head 9, for example. The control unit 4 performs the various processes according to a control program. The control unit 4 is a processor such as a CPU (central processing unit). The control unit 4 accesses the storage unit 3 and reads data and the like stored in the storage unit 3 as necessary. The control unit 4 performs processing for converting image data into print data, and the like.

The thermal head 9 has a function of emitting heat. The thermal head 9 generates heat under the control of the control unit 4, as will be described later in detail.

The conveying roller pair 5 is a roller pair for conveying the sheet 7. The conveying roller pair 5 is constituted by a pinch roller 5a and a pinch roller 5 b. The pinch roller 5a rotates in accordance with the driving of the sheet conveying portion 5M. The sheet conveying section 5M is, for example, a motor.

The platen roller 8 is provided to face a part of the thermal head 9. The platen roller 8 is configured to be movable by a driving unit not shown. The platen roller 8 contacts the thermal head 9 via the paper 7 and the ink sheet 6.

Hereinafter, the state of the platen roller 8 when the platen roller 8 is in contact with the thermal head 9 via the paper 7 and the ink sheet 6 is also referred to as a "platen contact state". The platen contact state is a state in which the paper 7 and the ink sheet 6 are sandwiched by the platen roller 8 and the thermal head 9.

In the platen contact state, the thermal head 9 heats the ink sheet 6, whereby the dye (ink) of the ink sheet 6 is transferred onto the paper 7.

The ink sheet driving portion 10 has a function of rotating the spool 10 b. The reel spool 10b rotates, and the ink roller 6rm takes up the ink sheet 6. The spool 10a rotates in accordance with the rotation of the spool 10 b. The reel 10a is rotated to supply the ink sheet 6 from the ink roller 6 r.

Referring to fig. 3, ink regions R10 are periodically arranged in the ink sheet 6 along the longitudinal direction (X-axis direction) of the ink sheet 6.

The dye 6y, 6m, 6c and the protective material 6op are provided in the ink region R10. The dyes 6y, 6m, 6c and the protective material 6op are each a transfer material that is transferred onto the paper 7 by being heated by the thermal head 9. The dyes 6y, 6m, 6c each show a color for transfer onto the paper 7. The dyes 6y, 6m, 6c show colors of yellow, magenta and cyan, respectively. Hereinafter, yellow, magenta and cyan are also referred to as "Y", "M" and "C", respectively. Hereinafter, the dye for Y, the dye for M, and the dye for C are also referred to as "color dyes", respectively.

The protective material 6op is a material (overcoat) for protecting the color transferred onto the paper 7. Specifically, the protective material 6op is a material for protecting the image formed on the sheet 7 by the dyes 6y, 6m, and 6 c. Hereinafter, the protective material 6OP is also referred to as "OP material". In addition, hereinafter, the region for forming an image in the sheet 7 is also referred to as a "print region".

In the printing process P, a unit printing process is performed. In the unit printing process, the thermal head 9 simultaneously conveys the ink sheet 6 and the paper 7 while heating the transfer material of the ink sheet 6 in the platen contact state. Thereby, the transfer material is transferred to the printing area of the paper 7 in a line.

The above-described unit printing process is repeated for each of the dyes 6y, 6m, and 6c as the transfer materials and the protective material 6op, whereby the dyes 6y, 6m, and 6c and the protective material 6op are transferred to the printing area of the paper 7 in the order of the dyes 6y, 6m, and 6c and the protective material 6 op. As a result, an image is formed in the print area of the sheet 7, and the image is protected by the protective material 6 op. This improves the light fastness of the image, the fingerprint fastness of the image, and the like.

Hereinafter, the image formed on the print area of the sheet 7 is also referred to as "image Gn". In addition, hereinafter, the direction in which the sheet 7 is conveyed is also referred to as "sheet conveying direction". In fig. 3, the sheet conveying direction is the X-axis direction.

There are a main scanning direction and a sub-scanning direction in a direction in which the thermal transfer printer 100 forms an image on a sheet. The sub-scanning direction is a sheet conveying direction. The main scanning direction is a direction orthogonal to the sub-scanning direction.

Hereinafter, the region of the ink sheet 6 provided with each of the dyes 6y, 6m, 6c and the protective material 6op is also referred to as "material region Rt 1". In addition, hereinafter, the length of the material region Rt1 in the sub-scanning direction (X-axis direction) is also referred to as "length Lx" or "Lx". Note that the size of the material region Rt1 corresponds to the size of 1 screen corresponding to the image Gn.

The length Lx is predetermined for reasons of manufacturing the ink sheet 6. Therefore, in the case of using such an ink sheet 6, the upper limit value of the length of the image Gn in the sub-scanning direction is the length Lx. Hereinafter, the length of the image Gn in the sub-scanning direction is also referred to as a "print size".

In general, in order to print an image having a size longer than the length Lx, a new ink sheet needs to be designed and manufactured. In addition, depending on the print size, an operation for replacing the ink sheet mounted on the thermal transfer printer is also required. Therefore, the cost of the ink sheet increases, and the ink sheet becomes complicated.

Therefore, it is considered to perform the above-described panorama printing. Fig. 4 is a diagram for explaining panorama printing. Hereinafter, an image to be panoramic-printed is also referred to as a "panoramic image Gw". In fig. 4, the main scanning direction is the Y-axis direction, and the sub-scanning direction is the X-axis direction.

Fig. 4(a) is a diagram showing an example of the panoramic image Gw. The panoramic image Gw has ends Ea, Eb. Hereinafter, the length of the panoramic image Gw in the main scanning direction is also referred to as "length H" or "H". In addition, hereinafter, the length of the panoramic image Gw in the sub-scanning direction is also referred to as "length Lp" or "Lp". The size of the panoramic image Gw is H × Lp.

The panoramic image Gw is composed of 2 or more pixels. Each pixel is expressed by a gray scale value (pixel value) indicating density. Hereinafter, data indicating the gradation value (pixel value) of a pixel is also referred to as "gradation data" or "pixel data". In addition, hereinafter, the highest density that the pixel can express is also referred to as "highest density". In addition, hereinafter, the lowest density that a pixel can express is also referred to as "lowest density".

In the present embodiment, as an example, the gradation value (pixel value) of a pixel of an image is expressed by 8 bits. In this case, the value of the gradation data is set to a value in the range of 0 to 255. Hereinafter, the gradation value corresponding to the lowest density is also referred to as "lowest density value". The minimum concentration value is, for example, 255. Hereinafter, the tone value corresponding to the highest density is also referred to as "highest density value". The highest concentration value is for example 0.

For example, when the gradation data indicates 0, the density of the pixel corresponding to the gradation data is the highest density. For example, when the gradation data indicates 255, the density of the pixel corresponding to the gradation data is the lowest density.

The gray scale value of the pixel is not limited to being expressed by 8 bits. The gray scale value of the pixel may be expressed by 10 bits, for example.

In the present embodiment, an example of panoramic printing using two images will be described for ease of understanding of the description. Hereinafter, the two images used for generating the panoramic image Gw will also be referred to as "images Gwa, Gwb". As will be described later in detail, the panoramic image Gw is a composite image expressed by the images Gwa and Gwb. The images Gwa and Gwb are formed (printed) on the sheet 7 in the order of the images Gwa and Gwb. The thermal transfer printer 100 heats the ink sheet 6 by the thermal head 9 to form a panoramic image Gw on the paper 7, as will be described later in detail.

Fig. 4(b) shows an example of the image Gwa. The image Gwa is an image from the center to the end Ea of the panoramic image Gw in the panoramic image Gw. The image Gwa has an image Gam and an end Gae. The end Gae is the rear end of the image Gwa. The end Gae has a front end Gae1 and a rear end Gae 2. The rear end Gae2 is the rear end of the image Gwa.

Fig. 4(c) shows an example of the image Gwb. The image Gwb is an image from the center to the end Eb of the panoramic image Gw in the panoramic image Gw. Image Gwb has end Gbe and image Gbm. The end Gbe is the tip of the image Gwb. End Gbe has a front end Gbe1 and a rear end Gbe 2. The front end Gbe1 is the front end of the image Gwb.

In addition, the panoramic image Gw has an overlapping region Rw. The overlap region Rw is a region in which the end Gbe of the image Gwb overlaps the end Gae of the image Gwa.

The shape of the overlap region Rw is rectangular. The overlap region Rw has a front end Re1 and a rear end Re 2. The front end Gae1 of the end Gae corresponds to the front end Re1 of the overlap region Rw. The rear end Gbe2 of the end Gbe corresponds to the rear end Re2 of the overlap region Rw. Hereinafter, the length of the overlap region Rw in the sub-scanning direction is also referred to as "length dL" or "dL".

The overlap region Rw has 2 or more pixels arranged in a matrix. The 2 or more pixels arranged in the overlap region Rw form a matrix of m rows and n columns. m and n are each an integer of 2 or more. That is, the overlap region Rw has m rows and n columns (lines). In the overlap region Rw, the number of pixels arranged in the sub-scanning direction is n. In addition, m pixels are arranged in each column. The number of pixels included in the overlap region Rw is k (an integer of 2 or more). k is a number calculated by the formula m × n.

Hereinafter, the length of the image Gwa in the sub-scanning direction is also referred to as "length L1" or "L1". In addition, hereinafter, the length of the image Gam in the sub-scanning direction is also referred to as "length La" or "La". The length L1 is La + dL. In addition, the size of the image Gwa is H × L1. In addition, with respect to L1, a relational expression of L1< Lx holds.

In addition, hereinafter, the length of the image Gwb in the sub-scanning direction is also referred to as "length L2" or "L2". Hereinafter, the length of the image Gbm in the sub-scanning direction is also referred to as "length Lb" or "Lb". The length L2 is Lb + dL. The size of the image Gwb is H × L2. In addition, with respect to L2, a relational expression of L2< Lx holds. The length LP of the panoramic image Gw is expressed by the following expression 1.

[ number 1 ]

Lp-L1 + L1-dL … (formula 1)

Next, a process for performing panorama printing (hereinafter also referred to as "panorama printing process") will be described. Fig. 5 is a flowchart of panorama printing processing according to embodiment 1 of the present invention. In the present embodiment, a process when forming the panoramic image Gw using two images will be described in order to make the process easy to understand. As an example, the two images are the image Gwa of fig. 4(b) and the image Gwb of fig. 4 (c). Hereinafter, the image to be printed is also referred to as an "object image".

In the panorama printing process, the processing from step S110 to step S140 corresponds to the preliminary processing for performing steps S150 and S160.

In the panorama printing process, first, the process of step S110 is performed. In step S110, a resizing process is performed. In the resizing process, the control unit 4 changes the size of the target image so that the size of the target image becomes H × Lp. As an example, the image obtained by the resizing processing is the panoramic image Gw of fig. 4 (a).

When the size of the target image is H × Lp, the size of the target image is not changed. In this case, the target image is, for example, a panoramic image Gw in fig. 4 (a). Hereinafter, an image that can be formed by the 1-pass printing process P is also referred to as a "unit image".

In step S120, image acquisition processing is performed. In the image acquisition process, the control unit 4 acquires the image Gwa of fig. 4(b) and the image Gwb of fig. 4(c) as cell images from the panoramic image Gw.

As described above, the size of the image Gwa is H × L1. L1 is La + dL. In addition, with respect to L1, a relational expression of L1< Lx holds. The size of the image Gwb is H × L2. L2 is Lb + dL. In addition, with respect to L2, a relational expression of L2< Lx holds.

Hereinafter, an image whose density changes slowly in the sub-scanning direction is also referred to as a "grayscale image". In addition, hereinafter, the end Gae whose concentration gradually decreases from the front end Gae1 to the rear end Gae2 of the end Gae is also referred to as "end Gar". The end portion Gar is a gray image. In addition, hereinafter, the end Gbe in which the concentration of the end Gbe gradually increases from the front end Gbe1 of the end Gbe to the rear end Gbe2 of the end Gbe is also referred to as "end Gbr". The end Gbr is a grayscale image.

In step S130, gradation processing for generating a gradation image is performed. In the gradation processing, the control section 4 corrects the density (gradation value) of 2 or more pixels included in the end Gae so that the end Gae of the image Gwa becomes the end Gar (gradation image). The controller 4 corrects the density (gradation value) of 2 or more pixels included in the edge Gbe so that the edge Gbe of the image Gwb becomes the edge Gbr (gradation image).

Hereinafter, the process of correcting the gradation value will also be referred to as "gradation correction process". Specifically, in the gradation processing, the gradation correction processing is performed on each of the end Gae and the end Gbe.

For example, the gradation correction processing is performed using the correction table T1 of fig. 6 and the correction table T2 of fig. 7. The correction table T1 is a table for correcting the density (gradation value) of each pixel of the end Gae. The correction table T2 is a table for correcting the density (gradation value) of each pixel of the end portion Gbe.

Referring to fig. 6, the correction table T1 shows 2 or more coefficients for correcting the density (gradation value). Values in the range of 0 to 1 are set for each coefficient. The "gradation" of the correction table T1 indicates a gradation value set in a pixel (gradation data). In the correction table T1, the lowest density value as a gradation value is 255. In the correction table T1, the highest density value as a gradation value is 0.

The "position x" of the correction table T1 refers to a position in the sub-scanning direction of the overlap region Rw. That is, "position x" is the position of n columns included in the overlap region Rw. The positions Lc1, Lc2,. cndot.. cndot.Lcn are the positions of the n columns.

For example, the position Lc1 is the position of the column closest to the leading end Re1 of the overlap region Rw, among the n columns. Further, for example, the position Lcn is a position of a column closest to the rear end Re2 of the overlap region Rw, among the n columns.

The correction table T2 in fig. 7 is the same as the correction table T1, and therefore, detailed description thereof will not be repeated. Note that, since the transfer characteristics of the dye differ depending on the color, correction tables T1, T2 corresponding to Y, M and C, respectively, were used. The correction tables T1 and T2 are stored in advance in the memory 3. The coefficients in the correction tables T1 and T2 are set to appropriate values by repeating experiments or the like. The experiment includes printing process, coefficient change, and the like.

Hereinafter, each pixel included in each of the end Gae and the end Gbe is also referred to as a "target pixel". In addition, hereinafter, each pixel included in each of the end portion Gar and the end portion Gbr is also referred to as a "correction pixel". In the correction tables T1 and T2, the coefficient specified by the position x and the gradation value is also referred to as an "object coefficient".

The correction of the gradation value in the gradation correction processing is performed by multiplying the gradation value of the target pixel by the target coefficient. For example, assume that the gradation value of a certain target pixel existing in the column of the position Lcn at the end Gae is 128. In this case, in the correction table T1 corresponding to the end Gae, the object coefficient specified by the position Lcn and the gradation value "128" is 0.13. In this case, the control unit 4 sets a value obtained by multiplying 128 by 0.13 as the gradation value of the correction pixel corresponding to the target pixel.

In the gradation correction processing, such correction of the gradation value is performed for k pixels included in the end Gae. Hereinafter, the Y component of the image is also referred to as "Y image". The Y image is a yellow image. In addition, hereinafter, the M component of an image is also referred to as an "M image". The M image is a magenta image. In addition, hereinafter, the C component of the image is also referred to as "C image". The C image is an image of cyan.

The Y image, the M image, and the C image constituting the end Gae are subjected to the above-described correction of the gradation value. Thereby, the end Gae becomes the end Gar.

In the gradation correction processing, similarly to the end Gae, the gradation value is corrected for the end Gbe using the correction table T2. Thus, end Gbe becomes end Gbr.

Hereinafter, the image Gwa in which the end Gae is made the end Gar by the gradation processing is also referred to as "image Gwar". The image Gwar has an end Gar. In addition, hereinafter, the image Gwb in which the edge Gbe is made the edge Gbr by the gradation processing is also referred to as "image Gwbr". The image Gwbr has an end Gbr. That is, the image Gwar and the image Gwbr are obtained by the gradation processing.

In addition, hereinafter, the heat emitted from the thermal head 9 is also referred to as "thermal energy" or "transfer energy". The closer the density of the pixels for transfer onto the paper is to the highest density, the greater the thermal energy emitted by the thermal head 9. In addition, the closer the density of the pixels for transfer onto the paper is to the lowest density, the smaller the thermal energy emitted by the thermal head 9.

Hereinafter, the value corresponding to the lowest concentration is also referred to as "lowest concentration value". For example, the lowest concentration value in the correction table T1 is 255. In addition, hereinafter, a value corresponding to the highest concentration is also referred to as "highest concentration value". For example, the highest concentration value in the correction table T1 is 0.

The closer the value of the gradation data is to the highest density value, the larger the heat energy is required. In addition, the closer the value of the gradation data is to the minimum density value, the smaller the heat energy is required. Hereinafter, the high-density pixel corresponding to the large thermal energy is also referred to as a "high-density pixel". In addition, hereinafter, the pixel of low density corresponding to small thermal energy is also referred to as "low density pixel".

The position where the high density pixel on the paper develops color is different from the position where the low density pixel on the paper develops color. Hereinafter, this phenomenon will be described with reference to fig. 8. In the panoramic image Gw in fig. 8(a), the density of the upper pixels of the panoramic image Gw is set to the highest density. In the panoramic image Gw in fig. 8(a), the density of the pixels at the lower end of the panoramic image Gw is set to the lowest density. In the panoramic image Gw in fig. 8(a), the closer to the lower end of the panoramic image Gw, the closer to the lowest density the density set for the pixel is.

Here, it is assumed that the processing of step S110 to step S130 is performed on the panoramic image Gw in fig. 8 (a). In this case, the above-described image Gwar and image Gwbr are obtained by the processing of step S130.

Here, it is assumed that the thermal transfer printer 100 performs printing processing in the overlap region Rw in such a manner that the end Gbr of the image Gwbr overlaps the end Gar of the image Gwar. In this printing process, after an image Gwar is formed on the sheet 7, an image Gwbr is formed on the sheet 7.

In this case, the image Gwar formed on the sheet 7 is as shown in the image Gwar of fig. 8 (b). Further, the image Gwbr formed on the sheet 7 is as shown in the image Gwbr of fig. 8 (b). The panoramic image Gw formed on the sheet 7 is as shown by the panoramic image Gw in fig. 8 (c).

As shown in fig. 8(b), at the end portion Gar, the lower the density of the pixel, the more distant the rear end Re2 of the overlap region Rw is, the color develops. That is, the contour of the end portion gar (Gae) on the rear end Gae2 side is a curved line. Hereinafter, the profile of the rear end Gae2 side of the end portion gar (Gae) is also referred to as "rear end side profile".

As shown in fig. 8(b), at the end Gbr, the lower the pixel density, the more distant the color develops at the tip Re1 of the overlap region Rw. That is, the profile of the end gbr (gbe) on the leading end Gbe1 side is a curved line. Hereinafter, the profile on the leading end Gbe1 side of the end portion gbr (gbe) is also referred to as "leading end side profile".

Therefore, assuming that the end Gbr of fig. 8(b) overlaps the end Gar of fig. 8(b) in the overlapping region Rw, the unevenness shown in fig. 8(c) occurs. The closer the density of the 2 pixels overlapped with each other is to the minimum density, the more likely the unevenness is to occur.

For example, as shown in fig. 8(b), when the rear end side contour of the end portion Gar and the front end side contour of the end portion Gbr appear as a curve on the sheet 7, the unevenness shown in fig. 8(c) is likely to occur. That is, as shown in fig. 8(b), in a state where the color development positions of 2 or more pixels along the main scanning direction (Y-axis direction) are not fixed at a certain position in the sub-scanning direction, unnatural unevenness is likely to occur due to density variations of prints, positional variations of prints, and the like.

Therefore, in order to solve the above problem, the coefficient change process is performed in step S140. Hereinafter, a straight line along the main scanning direction is also referred to as "straight line Lm".

In the coefficient changing process, a terminal-corresponding coefficient changing process is performed to change the coefficients of the correction tables T1 and T2 so that the rear-end side contour of the end portion gar (gae) and the front-end side contour of the end portion gbr (gbe) appear as a straight line Lm on the paper sheet 7. The end correspondence coefficient change processing is performed based on the magnitude (gradation value) of the thermal energy emitted from the thermal head 9.

In the end-corresponding coefficient change processing, for example, in the correction table T1, the degree of change of the coefficient is larger as the tone value corresponding to the coefficient is closer to the lowest density value (255).

In the end-correspondence coefficient changing process, for example, an end-correspondence coefficient changing step is performed as an experiment. Specifically, in the end correspondence coefficient changing step, for example, the operator confirms whether or not the thermal transfer printer 100 prints the image Gwar obtained from the correction table T1, and the contour of the rear end side of the end portion Gar is displayed as the straight line Lm on the sheet 7. For example, when a part of the contour of the rear end side of the end portion Gar is displayed in the form of a curve, the operator performs an operation of changing the coefficient of 1 or more of the correction table T1 corresponding to the curve using the information processing device 200. The control unit 4 changes the coefficient of the correction table T1 equal to or greater than 1 in accordance with the operation.

In the end-correspondence coefficient changing process, this end-correspondence coefficient changing step is repeated until the contour of the rear end side of the end portion Gar is displayed as a straight line Lm on the sheet 7.

The coefficients of the correction table T2 are also changed in the same manner as the correction table T1.

Hereinafter, the correction table T1 in which the coefficients are changed so that the contour of the rear end side of the end portion gar (gae) is displayed on the sheet 7 as a straight line Lm is also referred to as "correction table T1A". Hereinafter, the correction table T2 in which the coefficient is changed so that the front end side contour of the end gbr (gbe) is displayed on the paper sheet 7 as a straight line Lm is also referred to as "correction table T2A".

The above-described end-corresponding coefficient change processing is performed in the coefficient change processing, thereby obtaining the correction table T1A and the correction table T2A.

In step S150, gradation processing a is performed. In contrast to the gradation processing, the gradation processing a uses the correction table T1A and the correction table T2A instead of the correction table T1 and the correction table T2, which is different. The processing other than the gradation processing a is the same as the gradation processing, and therefore detailed description thereof will not be repeated.

Fig. 9 is a diagram for explaining a state where an image obtained by the gradation processing a is printed. Fig. 9(a) shows a panoramic image Gw. Fig. 9(b) shows a printed image Gwar. Fig. 9(c) shows the printed image Gwbr.

By the gradation processing a, the image gwar (gae) and the image gwbr (gbe) are obtained in the same manner as the gradation processing. When the image Gwar obtained by the gradation processing a is printed on the sheet 7, the contour of the rear end side of the end portion gar (gae) is displayed as a straight line Lm on the sheet 7 as shown in fig. 9 (b).

When the image Gwbr obtained by the gradation processing a is printed on the paper 7, the contour of the tip of the end gbr (gbe) is displayed as a straight line Lm on the paper 7 as shown in fig. 9 (b).

In step S160, a printing process Pw is performed. In the printing process Pw, the image Gwar and the image Gwbr are printed on the sheet 7 in the order of the image Gwar and the image Gwbr. In the printing process Pw, printing is performed in the overlap region Rw so that the end gbr (gbe) of the image Gwbr overlaps the end gar (gae) of the image Gwar.

In this case, the control unit 4 controls the amount of heat (thermal energy) emitted from the thermal head 9 in the printing process Pw. That is, in the printing process Pw, the thermal head 9 emits heat according to the control of the control unit 4. In the printing process Pw, when the end portion gar (gae) of the image Gwar and the end portion gar (gae) of the image Gwbr are printed, the thermal transfer printer 100 performs a gradation control process of forming the end portion gar (gae) and the end portion gbr (gbe) on the paper sheet 7.

In the gradation control process, the heat treatment Ha is performed while printing the end portion gar (gae) of the image Gwar. That is, the heat treatment Ha is a treatment of forming the end portion gar (gae) on the paper 7. Note that, since the processing of the portion other than the end portion gar (gae) in the print image Gwar is general processing, the description thereof is omitted.

As described above, the end Gar of the image Gwar is the end Gae whose density gradually decreases from the front end Gae1 to the rear end Gae2 of the end Gae.

Therefore, in the heat treatment Ha, the thermal head 9 is heated so that the concentration of the end Gae gradually decreases from the front end Gae1 to the rear end Gae 2. In addition, in the heat treatment Ha, the thermal head 9 is further heated so that the color development profile of the ink sheet 6 on the rear end Gae2 side of the end Gae is aligned in parallel with the main scanning direction. That is, in the heat treatment Ha, the thermal head 9 is caused to emit heat so that the contour of the rear end side of the end Gae appears as a straight line Lm on the sheet 7.

Thereby, as shown in fig. 9(b), the contour of the rear end side of the end portion gar (gae) appears as a straight line Lm on the sheet 7. That is, the position where the contour of the rear end side of the end portion gar (gae) is colored on the paper 7 is a position on a straight line along the main scanning direction (Y-axis direction) regardless of the magnitude of the thermal energy (gradation value).

In the gradation control process, heat treatment Hb is performed at the time of printing the end gbr (gbe) of the image Gwbr. That is, the heat treatment Hb is a process of forming the end gbr (gbe) on the paper sheet 7. Note that, since the processing of the portion other than the edge gbr (gbe) of the print image Gwbr is general processing, the description thereof is omitted.

As described above, the end Gbr of the image Gwbr is the end Gbe in which the density of the end Gbe gradually increases from the front end Gbe1 of the end Gbe to the rear end Gbe2 of the end Gbe.

Therefore, in the heat treatment Hb, the thermal head 9 is heated so that the concentration of the end portion Gbe gradually increases from the front end Gbe1 toward the rear end Gbe 2. In the heat treatment Hb, the thermal head 9 is further heated so that the color development profile of the ink sheet 6 on the leading end Gbe1 side of the end portion Gbe is aligned in parallel with the main scanning direction. That is, in the heat treatment Hb, the thermal head 9 is heated so that the contour of the tip side of the end portion Gbe appears as a straight line Lm along the main scanning direction on the sheet 7.

Thereby, as shown in fig. 9(b), the front end side contour of the end portion gbr (gbe) appears as a straight line Lm on the paper sheet 7. That is, the position where the front end side contour of the end portion gbr (gbe) appears on the paper 7 is a position on a straight line along the main scanning direction (Y-axis direction) regardless of the magnitude of the thermal energy (gradation value).

As described above, the rear end side profile of the end portion gar (gae) and the front end side profile of the end portion gbr (gbe) are displayed as the straight line Lm along the main scanning direction on the paper sheet 7. Therefore, even if a variation in the environment or the like occurs during printing, the occurrence of unevenness can be suppressed. That is, a robust effect on unevenness can be obtained.

Therefore, by performing the printing process Pw described above, an image without unevenness such as the panoramic image Gw in fig. 9(c) can be obtained on the sheet 7.

As described above, according to the present embodiment, in the heat treatment Ha, the thermal head 9 is heated so that the color development profile of the ink sheet 6 on the rear end Gae2 side of the end Gae is aligned in parallel with the main scanning direction. That is, in the heat treatment Ha, the thermal head 9 is caused to emit heat in such a manner that the contour on the rear end Gae2 side of the end Gae appears as a straight line Lm along the main scanning direction on the sheet 7.

In the heat treatment Hb, the thermal head 9 is heated so that the color development profile of the ink sheet 6 on the leading end Gbe1 side of the end Gbe is aligned in parallel with the main scanning direction. That is, in the heat treatment Hb, the thermal head 9 is heated so that the contour of the leading end Gbe1 side of the end Gbe appears as a straight line Lm along the main scanning direction on the sheet 7.

Thus, regardless of the density of 2 or more pixels constituting the outline of the image edge, the outline can be displayed as a straight line along the main scanning direction on the sheet.

Further, according to the present embodiment, when panoramic printing is performed, it is possible to suppress occurrence of image defects (unevenness, boundary lines) and the like in the overlap region Rw. Therefore, the occurrence of density unevenness, color unevenness, and the like due to density variation of the print, positional variation of the print, and the like can be suppressed. Therefore, a high-quality panoramic image can be obtained without making the joint between the two images conspicuous.

In the related configuration A, B, the seam between the two images present in the overlapping area is not conspicuous. However, when density variation of print, positional variation of print, or the like occurs, defects such as density unevenness and color unevenness occur. Therefore, if such a problem occurs, there is a problem that the print quality is degraded.

Therefore, the thermal transfer printer 100 according to the present embodiment is configured as described above. Therefore, the thermal transfer printer 100 according to the present embodiment can solve the above-described problems.

< embodiment 2>

The configuration of the present embodiment is a configuration using a coefficient calculated based on thermal energy (hereinafter also referred to as "configuration CtA"). First, the relationship between the thermal energy and the position at which the color dye (ink) is transferred will be described with reference to fig. 10. As described above, the position in the sub-scanning direction of the overlap region Rw is expressed as "position x" or "x". That is, the position x corresponds to the position x shown in the correction tables T1, T2.

Hereinafter, the coefficient used for generating a grayscale image is also expressed as "coefficient f (x)" or "f (x)". The coefficient f (x) is set to a value in the range of 0 to 1. Hereinafter, the thermal energy emitted from the thermal head 9 is also expressed as "thermal energy E" or "E". Fig. 10 is a diagram for explaining characteristics regarding thermal energy.

Fig. 10(a) is a diagram showing a graph Gf1 showing characteristics of thermal energy E with respect to a position x. The graph Gf1 shows characteristics corresponding to the end Gbe of the image Gwb existing in the overlap region Rw. The end Gbe is an image existing in the overlap region Rw. The characteristic corresponding to the end Gae of the image Gwa existing in the overlap region Rw is a characteristic in which the characteristic shown in the graph Gf1 is inverted in the left-right direction. Therefore, description of the characteristics corresponding to the end Gae of the image Gwa is omitted.

The horizontal axis of the graph Gf1 represents the position x. The vertical axis of the graph Gf1 represents the thermal energy E. The closer the gradation value is to the highest density value, the greater the thermal energy E corresponding to the gradation value. In addition, the closer the gradation value is to the lowest density value, the smaller the heat energy E corresponding to the gradation value. Therefore, the thermal energy E is in a proportional relationship with the gradation value (density).

In the graph Gf1, the position where x is 0 corresponds to the position of the tip Gbe1 of the end Gbe. The position where X is X0 corresponds to the position of the rear end Gbe2 of end Gbe.

The coefficient f (x) at position 0 has a value of 0. In addition, the coefficient f (X) at the position X0 has a value of 1. The coefficient f (X) is a coefficient whose value gradually increases from the position 0 to the position X0. For example, 2 or more coefficients corresponding to the gradation value 255 of the correction table T2 in fig. 7 are set for the coefficient f (x).

In the graph Gf1, as an example, E0, En-1, En, EN are shown as values of the thermal energy E. The thermal energy E0 is the lowest value (threshold value) required for the color dye (ink) to be transferred onto the paper sheet 7. That is, by supplying heat energy (heat) above the heat energy E0 to the color dye, the color dye is transferred onto the paper sheet 7.

In the graph Gf1, a characteristic line obtained by multiplying the coefficient f (x) by the thermal energy E is shown. For example, the characteristic line of f (x) × EN is a characteristic line obtained by multiplying the coefficient f (x) by the thermal energy EN. For example, since the value of the coefficient f (X) at the position X0 is 1, the thermal energy corresponding to the position X0 is EN.

The position x indicates a position where the color dye is transferred by the thermal energy E. The position where the color dye is transferred refers to a position where a pixel (color dye) develops color on the paper 7 (hereinafter also referred to as "color development position").

According to the graph Gf1, the color development positions corresponding to the thermal energies E0, En-1, En, EN are positions XN, Xn-1, X0, respectively. The color development position corresponding to the heat energy E0 is the position XN. That is, the color development position changes according to the magnitude of the heat energy E. Therefore, as described above, in the overlap region Rw in fig. 8(b), the color development position of the pixel (high density pixel) corresponding to the large thermal energy E is different from the color development position of the pixel (low density pixel) corresponding to the small thermal energy E.

Hereinafter, the color development position is also referred to as "color development position X" or "X". The color development position X corresponds to the position X of the graph Gf 1. The graph in which the abscissa represents the thermal energy E and the ordinate represents the color development position X (position X) is the graph Gf2 of fig. 10 (b). The relationship between E and X is expressed by the following formula 2.

Number 2

Equation 2 is obtained using the thermal energy E0 (threshold value) and the angle θ formed by E and X. The graph Gf2 shows that the color development position X differs depending on the magnitude of the heat energy. That is, as shown in the graph Gf1 of fig. 10(a) and the graph Gf2 of fig. 10(b), the color development position differs depending on the magnitude of the heat energy. Therefore, the defects (for example, unevenness) described with reference to fig. 8(b) and 8(c) may occur.

Therefore, in order to prevent the above-described problem, it is necessary to align the color-developing positions different depending on the magnitude of the thermal energy at a certain position as shown in formula 2. If the color development position corresponding to a certain thermal energy En is the same as that of the thermal energy En, the following offset dXn needs to be added to the position x (sub-scanning direction). Offset dXn is a correction based on position x and thermal energy E.

Specifically, the offset dXn is expressed by the following formula 3.

[ number 3 ]

The coefficient f (x) with respect to the position x (sub-scanning direction) is determined as a coefficient fn (x) for each transfer energy En. The coefficient fn (x) is expressed by the following formula 4 using dXn of formula 3.

[ number 4 ]

Fn (x) ═ F (x + dXn) … (formula 4)

In addition, with respect to Fn (x), a relational expression of 0.0. ltoreq. Fn (x) 1.0 holds. The coefficient fn (x) is a coefficient calculated using the offset dXn. The coefficient fn (x) of equation 4 is a coefficient for displaying the front end side contour of the end gbr (gbe) of the image Gwbr as a straight line Lm on the sheet 7.

The coefficient fn (x) shown in equation 4 is multiplied by the thermal energy En, thereby obtaining the characteristic (fn (x) xn) shown in the graph Gf3 of fig. 11. As a result, as shown in fig. 9(b), the front-end-side contour of the end gbr (gbe) of the image Gwbr appears as a straight line Lm along the main scanning direction on the sheet 7. That is, the position where the front end side contour of the end portion gbr (gbe) appears on the paper 7 is a position on a straight line along the main scanning direction (Y-axis direction) regardless of the magnitude of the thermal energy (gradation value).

In configuration CtA of the present embodiment, the processing using the above expression (hereinafter also referred to as "panorama printing processing a") is performed. Fig. 12 is a flowchart of panorama printing processing a according to embodiment 2 of the present invention. In fig. 12, the processing of the same step number as that of fig. 5 is the same as that described in embodiment 1, and thus detailed description thereof will not be repeated. Hereinafter, differences from embodiment 1 will be mainly described.

In the panorama printing process a, the processes of steps S110, S120, and S130 are performed as in embodiment 1. After the process of step S130, step S140A is performed.

In step S140A, coefficient change processing a is performed. In the coefficient change processing a, the control unit 4 changes the coefficients of the correction tables T1 and T2 so that the rear-end-side contour of the end portion gar (gae) and the front-end-side contour of the end portion gbr (gbe) appear as a straight line Lm on the paper sheet 7. The coefficient is changed based on the magnitude (gradation value) of the thermal energy E.

Here, each coefficient shown in the correction table T2 of fig. 7 is assumed to be a coefficient f (x). In this case, the control unit 4 changes the 2 or more coefficients f (x) shown in the correction table T2 to the coefficients fn (x) shown in expressions 4 and 3, respectively.

Thereby, the 2 or more coefficients shown in the correction table T2 are changed to coefficients for displaying the front end side contour of the end portion gbr (gbe) on the paper sheet 7 as a straight line Lm along the main scanning direction.

Hereinafter, the correction table T2 in which the coefficients are changed by the coefficient change processing a is also referred to as "correction table T2A". The correction table T2A is a table for displaying the front end side contour of the end portion gbr (gbe) as a straight line Lm on the paper sheet 7.

As described above, the thermal energy E is in a proportional relationship with the gradation value. Therefore, each coefficient fn (x) shown in the correction table T2A is a value calculated by equations 3 and 4 using the value of the thermal energy E corresponding to the gradation value. For example, in the correction table T2A (correction table T2), the value of the coefficient fn (x) specified by the gradation value 0 and the position Lc1 is a value calculated by equations 3 and 4 using the value of the thermal energy E corresponding to the gradation value 0.

In the coefficient change process a, the controller 4 also changes 2 or more coefficients shown in the correction table T1 to the coefficient fn (x) in the same manner as in the correction table T2. The coefficient fn (x) used for the correction table T1 is an equation derived from a graph obtained by inverting the graph Gf1 in the left-right direction, as in equations 2, 3, and 4. Hereinafter, the correction table T1 in which the coefficients are changed by the coefficient change process a is also referred to as "correction table T1A". The correction table T1A is a table for displaying the contour of the rear end side of the end portion gar (gae) as a straight line Lm on the sheet 7.

Then, the gradation processing a of step S150 and the printing processing Pw of step S160 are performed in the same manner as in embodiment 1. By performing the gradation processing a, an image gwar (gae) and an image gwbr (gbe) are obtained. The end portion gar (gae) of the image gwar (gae) is an image generated by using the coefficient fn (x) shown in the correction table T1. The end gbr (gbe) of the image gwbr (gbe) is an image generated by using the coefficient fn (x) shown in the correction table T2.

In the printing process Pw, the gradation control process (the heat process Ha and the heat process Hb) described above is performed. Therefore, the same effect as that of embodiment 1 is obtained also in the panorama printing process a.

As described above, according to the present embodiment, as in embodiment 1, it is possible to suppress occurrence of image defects (unevenness, boundary lines) and the like in the overlap region Rw. Therefore, the occurrence of density unevenness, color unevenness, and the like due to density variation of the print, positional variation of the print, and the like can be suppressed. Therefore, a high-quality panoramic image can be obtained without making the joint between the two images conspicuous.

In addition, according to the present embodiment, it is not necessary to repeat experiments or the like as shown in embodiment 1 in order to calculate the coefficient by calculation. Therefore, the coefficients in the correction tables T1A and T2A can be obtained quickly.

< embodiment 3>

The configuration of the present embodiment is a configuration for adjusting the tone of a halftone pixel (hereinafter also referred to as "configuration CtB"). A halftone pixel refers to a pixel having a gray value in the middle of the lowest density value and the highest density value. Halftone pixels are also referred to as gray pixels. Hereinafter, the overlapping region Rw is also referred to as "region Rw".

In addition, hereinafter, an image within the region Rw in the image Gwa or the image Gwb is also referred to as an "in-region image". For example, the image in the region of the image Gwa is the end gae (gar) (see fig. 4 (b)). In addition, hereinafter, an image outside the region Rw in the image Gwa or the image Gwb is also referred to as an "outside-region image". For example, the image outside the area of the image Gwa is an image Gam (see fig. 4 (b)).

The color development sensitivity of the dye to thermal energy is not fixed. Therefore, for example, the tone of the halftone pixels contained in the image within the area of the image gwar (gwa) obtained by the gradation processing of step S130 of fig. 5 is likely to be different from the tone of the halftone pixels contained in the image outside the area of the image gwar (gwa). Hereinafter, in an image of an object subjected to gradation processing, the tone of a halftone pixel of the image is also referred to as "original tone". The original tone is a tone represented by a halftone pixel to which image processing is not applied.

For example, in a state where the thermal energy supplied to the color dye is small, the color development sensitivity of the dye 6m is smaller than those of the dyes 6c and 6 y. Therefore, the images generated by the dyes 6y, 6m, and 6c in the above state become images strong in blue.

Here, it is assumed that the image Gwar of fig. 13 is obtained by the gradation processing. In this case, the tone of halftone pixels within the region Rg1 (in-region image) of the image Gwar is more intense in blue than the tone of halftone pixels in a portion outside the region Rw in the image Gwar. Therefore, in a state where the end Gbr of the image Gwbr is superimposed on the end Gar of the image Gwar, the tone of the halftone pixel having a tone change is normally subjected to the following processing N as shown by the original tone. In this processing N, the tone of halftone pixels in the region Rg2 (intra-region image) of the image Gwbr in fig. 13 is changed. Note that the process N is not the process performed by the configuration CtB of the present embodiment.

Hereinafter, the characteristic line for adjusting the density (gradation value) of an image is also referred to as a "density adjustment line". The density adjustment line has the same function as the 2 or more coefficients shown in the correction tables T1 and T2.

In addition, hereinafter, the density adjustment line for adjusting the density of the Y image is also referred to as "adjustment line Y". In addition, hereinafter, the adjustment line Y for adjusting the density of the Y image of the end Gae of the image Gwa is also referred to as "adjustment line Y1" or "Y1". In addition, hereinafter, the adjustment line Y for adjusting the density of the Y image of the end Gbe of the image Gwb is also referred to as "adjustment line Y2" or "Y2".

In addition, hereinafter, a density adjustment line for adjusting the density of the M image is also referred to as "adjustment line M". In addition, hereinafter, the adjustment line M for adjusting the density of the M image of the end Gae of the image Gwa is also referred to as "adjustment line M1" or "M1". In addition, hereinafter, the adjustment line M for adjusting the density of the M image of the end Gbe of the image Gwb is also referred to as "adjustment line M2" or "M2".

In addition, hereinafter, the density adjustment line for adjusting the density of the C image is also referred to as "adjustment line C". In addition, hereinafter, the adjustment line C for adjusting the density of the C image of the end Gae of the image Gwa is also referred to as "adjustment line C1" or "C1". In addition, hereinafter, the adjustment line C for adjusting the density of the C image of the end Gbe of the image Gwb is also referred to as "adjustment line C2" or "C2".

Specifically, in the processing N, the change of the tone of the halftone pixels in the region Rg2 (region Rw) of the image Gwbr in fig. 13 is performed based on fig. 14, for example. Positions Xa and Xb shown in fig. 14 correspond to positions Xa and Xb shown in fig. 13. Specifically, adjustment lines M2, Y2, and C2 are set as shown in fig. 14. Thus, the edge gae (gar) whose density is corrected by the adjustment lines M2, Y2, and C2 becomes an image with strong red color. Thus, by overlapping the strong red end Gbr with the strong blue end Gar, the tone of the halftone pixel having a tone change can display the original tone.

However, in a state where the strong red end Gbr is superimposed on the strong blue end Gar, unnatural unevenness is likely to occur due to variations in density of prints, positional variations of prints, and the like.

Therefore, in the configuration CtB of the present embodiment, the adjustment of the color tone of the halftone pixels is performed. Configuration CtB can be applied to the panorama printing process of fig. 5. Hereinafter, the panorama printing process of fig. 5 to which the composition CtB is applied is also referred to as "panorama printing process B".

Fig. 15 is a flowchart of panorama printing processing B according to embodiment 3 of the present invention. In fig. 15, the processing of the same step number as that of fig. 5 is the same as that described in embodiment 1, and therefore detailed description thereof will not be repeated. Hereinafter, differences from embodiment 1 will be mainly described.

In the panorama printing process B, the processes of steps S110, S120, and S130 are performed as in embodiment 1. After the process of step S130, step S140B is performed.

In step S140B, coefficient change processing B is performed. In the coefficient change processing B, tone-corresponding coefficient change processing for changing the coefficients of the correction tables T1 and T2 is performed so that the tone of halftone pixels of the image in the region of the image Gwa is the same as the tone of halftone pixels of the image in the region of the image Gwb. Note that the color tone-corresponding coefficient change processing may be processing for changing the coefficients of the correction tables T1 and T2 so that the color tone of the halftone pixels of the image within the area of the image Gwa and the image Gwb is the same as the color tone of the halftone pixels of the image outside the area.

In the coefficient change processing B, the end-based coefficient change processing for changing the coefficients of the correction tables T1 and T2 is further performed so that the rear-end-side contour of the end portion gar (gae) and the front-end-side contour of the end portion gbr (gbe) are displayed as a straight line Lm on the sheet 7.

In the tone correspondence coefficient change process, the tone of the halftone pixels of the image (region Rg1) in the region of the image Gwar is adjusted so as to be the same as the tone of the halftone pixels of the image (region Rg2) in the region of the image Gwbr. That is, the tone adjustment is performed in such a manner that the tone of the halftone pixels of the region Rg1 of the image Gwar and the tone of the halftone pixels of the region Rg2 of the image Gwbr display the original tone.

For each pixel of the area Rg1 of the image Gwar, for example, the color tone is adjusted using the adjustment lines Y1, M1, and C1 adjusted as shown in fig. 16. Further, for each pixel of the area Rg2 of the image Gwbr, the color tone is adjusted using the adjustment lines Y2, M2, and C2 adjusted as shown in fig. 16, for example. Note that the adjustment lines Y1, M1, C1, Y2, M2, and C2 are set so that the color tone of the halftone pixels displays the original color tone.

For example, in the CIE L × a × b color space, the adjustment lines Y1, M1, C1, Y2, M2, and C2 are preferably adjusted so that the relative difference value between the coordinate value of a × b corresponding to the hue and the original hue is 3 or less. Then, the controller 4 changes the coefficients of the correction table T1 corresponding to Y, M, C using the adjusted adjustment lines Y1, M1, and C1. The controller 4 also changes the coefficients of the correction table T2 corresponding to Y, M, C using the adjusted adjustment lines Y2, M2, and C2.

Note that the tone mapping coefficient changing process may be performed by a method other than the above method. For example, in the color tone correspondence coefficient changing process, an experimental color tone correspondence coefficient changing step may be performed. In the tone correspondence coefficient changing step, for example, the thermal transfer printer 100 prints the image Gwar obtained from the correction table T1, and a color measuring device or the like measures the tone of the halftone pixels at the end portion Gar. When the tone of the halftone pixel is different from the original tone, the operator uses the information processing device 200 to change the coefficient of the correction table T1 so that the tone of the halftone pixel approaches the original tone. The control unit 4 changes the coefficient of the correction table T1 in accordance with this operation. In the tone-correspondence coefficient changing process, such a tone-correspondence coefficient changing step is repeated until the tone of the halftone pixel becomes the original tone.

The coefficients of the correction table T2 are also changed by the same method as the correction table T1.

In the coefficient change processing B, the above-described end-corresponding coefficient change processing is further performed as in embodiment 1. Note that the description of the end-correspondence coefficient change processing is omitted.

Hereinafter, the correction table T1 in which the coefficients are changed by the tone-corresponding coefficient change process and the end-corresponding coefficient change process is also referred to as "correction table T1A". Hereinafter, the correction table T2 in which the coefficients are changed by the tone-corresponding coefficient change process and the end-corresponding coefficient change process is also referred to as "correction table T2A".

The correction tables T1A and T2A are tables for making the tone of halftone pixels of an image in the region of the image Gwa the same as the tone of halftone pixels of an image in the region of the image Gwb. The correction tables T1A and T2A are tables for making the tone of halftone pixels in the image Gwa and the image Gwb in the region the same as the tone of halftone pixels in the image outside the region.

The correction table T1A may be a table for displaying the contour of the rear end side of the end portion gar (gae) as a straight line Lm on the sheet 7. The correction table T2A may be a table for displaying the front end side contour of the end gbr (gbe) as a straight line Lm on the sheet 7.

Then, the gradation processing a of step S150 is performed in the same manner as in embodiment 1. Next, step S160B is performed.

In step S160B, a printing process PwB is performed. In the printing process PwB, the contents of the heat treatment Ha and the heat treatment Hb are different from the printing process Pw of step S160. The other processing of the printing process PwB is the same as the printing process Pw, and thus detailed description thereof will not be repeated.

In the printing process PwB, the heat treatment Ha and the heat treatment Hb are performed in the gradation control process, as in the printing process Pw. In the heat treatment Ha, the thermal head 9 is heated so that the color developed profile of the ink sheet 6 on the trailing end Gae2 side of the end Gae is aligned in parallel with the main scanning direction. That is, in the heat treatment Ha, the thermal head 9 is caused to emit heat so that the contour of the rear end side of the end Gae appears as a straight line Lm on the sheet 7.

In the heat treatment Hb, the thermal head 9 is heated so that the color developed profile of the ink sheet 6 on the leading end Gbe1 side of the end Gbe is aligned in parallel with the main scanning direction. That is, in the heat treatment Hb, the thermal head 9 is heated so that the contour of the tip side of the end portion Gbe appears as a straight line Lm along the main scanning direction on the sheet 7.

In addition, in the heat treatment Ha and the heat treatment Hb of the printing treatment PwB, the thermal head 9 is further heated so that the color tone of the halftone at the end Gae is the same as the color tone of the halftone at the end Gbe.

As described above, according to the present embodiment, the rear-end-side contour of the end portion gar (gae) and the front-end-side contour of the end portion gbr (gbe) are displayed as the straight line Lm along the main scanning direction on the sheet 7. Therefore, as in embodiment 1, the occurrence of image defects (unevenness, boundary lines) and the like can be suppressed in the overlap region Rw. Therefore, the occurrence of density unevenness, color unevenness, and the like due to density variation of the print, positional variation of the print, and the like can be suppressed. Therefore, a high-quality panoramic image can be obtained without making the joint between the two images conspicuous.

In addition, according to the present embodiment, the tone of the halftone at the end Gae is the same as the tone of the halftone at the end Gbe. In addition, the tone of the halftone pixels of the image within the region of the image Gwa and the image Gwb is the same as the tone of the halftone pixels of the image outside the region. Therefore, the occurrence of image defects (unevenness, boundary lines) and the like can be suppressed in the overlap region Rw.

In addition, according to the present embodiment, the occurrence of unevenness can be suppressed even when a variation in the environment or the like occurs during printing. That is, a robust effect on unevenness can be obtained.

Note that, in embodiment 2, the color tone-corresponding coefficient change process (hereinafter also referred to as "configuration CtBa") may be further performed before the coefficient change process a in step S140A in fig. 12. In the configuration CtBa, the processing of step S130 is followed by the color tone mapping coefficient changing processing, and the coefficient changing processing a of step S140A is performed. That is, in the configuration CtBa, the coefficient change processing a of step S140A is performed on the correction tables T1 and T2 in which the coefficients are changed by the tone-corresponding coefficient change processing.

(function block diagram)

Fig. 17 is a block diagram showing a characteristic functional configuration of the thermal transfer printer BL 10. The thermal transfer printer BL10 corresponds to the thermal transfer printer 100. That is, fig. 17 is a block diagram showing a main function related to the present invention among functions that the thermal transfer printer BL10 has.

The thermal transfer printer BL10 heats the ink sheet by the thermal head BL1, thereby forming a composite image represented by the 1 st image and the 2 nd image on the paper.

The composite image has an overlap region in which a 1 st edge portion, which is a rear edge portion of the 1 st image, overlaps a 2 nd edge portion, which is a front edge portion of the 2 nd image. The 1 st edge portion has a 1 st front edge corresponding to a front edge of the overlap region and a 1 st rear edge which is a rear edge of the 1 st image. The 2 nd edge portion has a 2 nd front edge which is a front edge of the 2 nd image and a 2 nd rear edge which corresponds to a rear edge of the overlap region.

The thermal transfer printer BL10 functionally includes a thermal head BL 1. The thermal head BL1 emits heat. The thermal head BL1 corresponds to the thermal head 9.

The thermal transfer printer BL10 performs gradation control processing for forming the 1 st edge and the 2 nd edge on the sheet. In the gradation control process, the 1 st heat treatment and the 2 nd heat treatment are performed.

In the 1 st heat treatment, the thermal head BL1 is heated so that the density of the 1 st edge gradually decreases from the 1 st leading edge to the 1 st trailing edge, and the developed color profile of the ink sheet on the 1 st trailing edge side of the 1 st edge is aligned in parallel with the main scanning direction.

In the 2 nd heat treatment, the thermal head BL1 is heated so that the density of the 2 nd end portion gradually increases from the 2 nd leading end to the 2 nd trailing end and the color development profile of the ink sheet on the 2 nd leading end side of the 2 nd end portion is aligned in parallel with the main scanning direction.

(other modification example)

The thermal transfer printer of the present invention has been described above based on the respective embodiments, but the present invention is not limited to the respective embodiments. Modifications that can be made to the embodiments by those skilled in the art without departing from the spirit of the invention are also included in the invention. That is, in the present invention, the respective embodiments may be freely combined, or may be appropriately modified or omitted within the scope of the present invention.

For example, a part of the panorama printing process in fig. 5, a part of the panorama printing process a in fig. 12, and a part of the panorama printing process B in fig. 15 may be performed by the information processing apparatus 200 instead of the control unit 4 of the thermal transfer printer 100.

For example, all or a part of the processes of steps S110 to S150 of the panorama printing process of fig. 5 may be performed by the information processing apparatus 200. In addition, the information processing apparatus 200 may transmit the data of the image obtained in step S150 to the thermal transfer printer 100, and the thermal transfer printer 100 may perform the process of step S160.

In addition, for example, all or a part of the processes of steps S110 to S150 of the panorama printing process a of fig. 12 may be performed by the information processing apparatus 200. In addition, the information processing apparatus 200 may transmit the data of the image obtained in step S150 to the thermal transfer printer 100, and the thermal transfer printer 100 may perform the process of step S160.

In addition, for example, all or a part of the processes of steps S110 to S150 of the panorama printing process B of fig. 15 may be performed by the information processing apparatus 200. In addition, the information processing apparatus 200 may transmit the data of the image obtained in step S150 to the thermal transfer printer 100, and the thermal transfer printer 100 may perform the process of step S160B.

In each of the above embodiments, for example, the number of images used for the composition of the panoramic image Gw may be2, or may be 3 or more.

The thermal transfer printer 100 may not include all the components shown in the drawings. That is, the thermal transfer printer 100 may include only the minimum components that can achieve the effects of the present invention.

The present invention has been described in detail, but the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that numerous modifications not illustrated can be devised without departing from the scope of the invention.

Description of the symbols

6 ink sheet, 7 paper, 9, BL1 thermal head, 100, BL10 thermal transfer printer.