阅读说明：本技术 热转移打印装置及热转移打印方法 (Thermal transfer printing device and thermal transfer printing method ) 是由 小高都明 于 2018-06-28 设计创作，主要内容包括：实现打印的图像画质的稳定化。本发明的热转移打印装置具有热敏头(1)及压印辊(2),将包括以面顺序设置的黄色层(51)、品红色层(52)及青色层(53)的1组墨层(50)连续地设置多组而成的墨带(5)和打印纸(7)重叠,在热敏头(1)与压印辊(2)之间进行搬送,并且,热敏头(1)将墨带(5)加热而转印墨,在打印纸(7)形成图像。该热转移打印装置包括：传感器(20),其检测墨层(50)的含墨量；及控制部(10),其根据传感器(20)的检测结果而控制形成图像时向热敏头(1)施加的能量。(The image quality of the printed image is stabilized. A thermal transfer printing apparatus includes a thermal head (1) and a platen roller (2), wherein an ink ribbon (5) in which a plurality of sets of 1 set of ink layers (50) including a yellow layer (51), a magenta layer (52), and a cyan layer (53) are provided in this order is stacked on a printing paper (7), and the printing paper is conveyed between the thermal head (1) and the platen roller (2), and the thermal head (1) heats the ink ribbon (5) to transfer the ink, thereby forming an image on the printing paper (7). The thermal transfer printing apparatus includes: a sensor (20) that detects the ink content of the ink layer (50); and a control unit (10) that controls the energy applied to the thermal head (1) when forming an image, based on the detection result of the sensor (20).)

A thermal transfer printing apparatus of type, comprising a thermal head and a platen roller, wherein an ink ribbon and a printing paper are overlapped and conveyed between the thermal head and the platen roller, and the thermal head heats the ink ribbon to transfer ink, thereby forming an image on the printing paper, wherein the ink ribbon is formed by continuously arranging a plurality of sets of 1 set of ink layers comprising a yellow layer, a magenta layer and a cyan layer arranged in a surface sequence,

the thermal transfer printing apparatus is characterized by comprising:

a sensor that detects an ink content of the ink layer; and

and a control unit that controls energy applied to the thermal head when an image is formed, based on a detection result of the sensor.

2. The thermal transfer printing apparatus of claim 1,

the sensor includes a light emitting portion that irradiates the ink ribbon with light, and a light receiving portion that receives the light transmitted through the ink ribbon.

3. The thermal transfer printing apparatus of claim 1 or 2,

the sensor is provided between an ink ribbon supply portion that supplies the ink ribbon and the thermal head.

4. The thermal transfer printing apparatus of claim 1 or 2,

the sensor is provided between the thermal head and a ribbon recovery unit that recovers a used ink ribbon.

5. The thermal transfer printing apparatus of claim 4,

the sensor detects an ink content of a printing area used when an image is formed on the printing paper and an ink content of an unprinted area not used when an image is formed.

6. The thermal transfer printing apparatus of claim 5,

the ink ribbon is provided with a yellow layer, a magenta layer, a cyan layer and a protective layer in the order of surface,

the thermal head transfers the protective layer onto an image formed on the printing paper,

the sensor includes a light emitting portion that irradiates light to the ink ribbon, and a light receiving portion that receives light transmitted through the ink ribbon, and measures transmitted light intensities of the printing region, the unprinted region, and the protective layer forming region of the yellow layer, the magenta layer, or the cyan layer.

7, A thermal transfer printing method, comprising the following steps:

drawing out the printing paper from the printing paper roll;

forming an image by transferring yellow, magenta and cyan onto printing paper by a thermal head using 1 set of ink layers in an ink ribbon formed by successively arranging a plurality of sets of 1 set of ink layers including a yellow layer, a magenta layer and a cyan layer arranged in a surface order;

detecting an ink content of the ink layer;

the energy applied to the thermal head at the time of forming an image is controlled based on the detected ink content.

8. The thermal transfer printing method of claim 7,

the ink content of the ink layer is detected before forming an image.

9. The thermal transfer printing method of claim 8,

after forming an image, an ink content of a printing area used when forming an image on the printing paper and an ink content of an unprinted area not used when forming an image in the ink layer are detected.

Technical Field

The present invention relates to a thermal transfer printing apparatus and a thermal transfer printing method.

Background

At present, the following thermal transfer printers are known: an ink ribbon and a printing paper are sandwiched between a thermal head and a platen roller, and the ink ribbon is heated from the thermal head to transfer ink of the ink ribbon to the printing paper in a pattern corresponding to an image.

In the ink ribbon, 1 dye layer set with a yellow layer, a magenta layer and a cyan layer in surface order is provided with a plurality of groups continuously. The ink ribbon drawn from the ink ribbon supply roller wound with the ink ribbon is collected by the thermal head to the ink ribbon collection roller.

The ink ribbon may have different ink contents (ink coating amounts) depending on a manufacturing factory and a manufacturing time. Even if the same printing energy is applied to the thermal head, the density of an image formed on the printing paper differs between the case of using an ink ribbon with a large ink content and the case of using an ink ribbon with a small ink content, and the image quality differs.

Even in the case of ink ribbons having the same ink content, the density and the like of an image formed on a printing paper vary depending on the ambient environment (temperature and humidity) until the ink ribbon is mounted on a thermal transfer printer or the installation environment of the thermal transfer printer, and thus the image quality varies.

Patent document 1: japanese laid-open patent publication No. 2009-83207

Disclosure of Invention

The present invention has been made in view of the above-described conventional circumstances, and an object of the present invention is to provide types of thermal transfer printing apparatuses and thermal transfer printing methods capable of stabilizing the image quality of a printed image.

A thermal transfer printing apparatus according to the present invention is a thermal transfer printing apparatus including a thermal head and a platen roller, in which a printing paper and an ink ribbon in which a plurality of sets of 1 set of ink layers including a yellow layer, a magenta layer, and a cyan layer are successively provided in this order are stacked, the printing paper is conveyed between the thermal head and the platen roller, the thermal head heats the ink ribbon to transfer ink, and an image is formed on the printing paper, the thermal transfer printing apparatus including: a sensor that detects an ink content of the ink layer; and a control unit that controls energy applied to the thermal head when an image is formed, based on a detection result of the sensor.

In the thermal transfer printing apparatus of the present invention, the sensor has a light emitting portion that irradiates light onto the ink ribbon and a light receiving portion that receives light transmitted through the ink ribbon.

In the thermal transfer printing apparatuses according to the present invention, the sensor is provided between an ink ribbon supply portion that supplies the ink ribbon and the thermal head.

In the thermal transfer printing apparatuses according to the present invention, the sensor is provided between the thermal head and an ink ribbon recovery unit that recovers a used ink ribbon.

In the mode thermal transfer printing apparatus of the present invention, the sensor detects the ink content in a printing area used when the printing paper forms an image and the ink content in an unprinted area not used when forming an image.

In the thermal transfer printing apparatus of the present invention, the ink ribbon is provided with a yellow layer, a magenta layer, a cyan layer, and a protective layer in this order on a surface, the thermal head transfers the protective layer onto an image formed on the printing paper, the sensor has a light emitting portion that irradiates the ink ribbon with light and a light receiving portion that receives light transmitted through the ink ribbon, and the sensor measures the transmitted light intensity of the printing region of the yellow layer, the magenta layer, or the cyan layer, the transmitted light intensity of the unprinted region, and the transmitted light intensity of the protective layer forming region.

The thermal transfer printing method of the present invention is characterized by comprising the steps of: drawing out the printing paper from the printing paper roll; forming an image by transferring yellow, magenta and cyan onto a printing paper by a thermal head using 1 set of ink layers in an ink ribbon in which 1 set of ink layers including a yellow layer, a magenta layer and a cyan layer are successively provided in a plurality of sets in a surface order; detecting an ink content of the ink layer; controlling energy applied to the thermal head when forming an image according to the detected ink content.

In the thermal transfer printing method of the modes of the invention, the ink content of the ink layer was detected before the image was formed.

In the thermal transfer printing method of the present invention, after an image is formed, the ink content of a print area used when the print paper forms an image and the ink content of an unprinted area not used when an image is formed in the ink layer are detected.

Effects of the invention

According to the present invention, the quality of printed images can be stabilized regardless of the ink content of the ink ribbon and the surrounding environment.

Drawings

Fig. 1 is a schematic configuration diagram of a thermal transfer printing apparatus according to embodiment 1 of the present invention.

Fig. 2 is a plan view of the ink ribbon.

Fig. 3 is a flowchart illustrating the thermal transfer printing method according to embodiment 1.

Fig. 4 is a flowchart illustrating the thermal transfer printing method according to embodiment 2.

Fig. 5 is a schematic configuration diagram of the thermal transfer printing apparatus according to embodiment 3.

Fig. 6 is a plan view showing an example of a print area and an unprinted area of the ink ribbon.

Fig. 7 is a flowchart illustrating the thermal transfer printing method according to embodiment 3.

Fig. 8 is a flowchart illustrating a thermal transfer printing method according to embodiment 4.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

[ embodiment 1 ]

Fig. 1 is a schematic configuration diagram of a thermal transfer printing apparatus according to embodiment 1 of the present invention, and fig. 2 is a plan view of an ink ribbon used in the thermal transfer printing apparatus. The thermal transfer printing apparatus prints an image by sublimation transfer of yellow, magenta, and cyan onto a printing sheet (printing paper or image receiving paper).

On the ink ribbon 5, a Y layer 51 including a yellow dye, an M layer 52 including a magenta dye, a C layer 53 including a cyan dye, and a protective (OP) layer 54 are provided in this order. The ink ribbon 5 may be provided with a black (Bk) melting layer. The thermal transfer printing apparatus includes a thermal head 1, and the thermal head 1 prints an image by sublimation transfer Y, M, C on a print sheet 7 (printing paper) using an ink ribbon 5, and forms a protective layer on the image.

A ribbon supply section 3 in which an ink ribbon 5 is wound is provided on the downstream side of the thermal head 1, and a ribbon recovery section 4 is provided on the upstream side of the thermal head 1. The ink ribbon 5 drawn out from the ribbon supply unit 3 is collected by the thermal head 1 into the ribbon collection unit 4.

A platen roller 2 is rotatably provided below the thermal head 1. The printing unit 40 including the thermal head 1 and the platen roller 2 heats the ink ribbon 5 with the print sheet 7 and the ink ribbon 5 interposed therebetween to thermally transfer ink on the print sheet 7, thereby forming an image.

In addition, the printing section 40 heats the OP layer 54 to laminate a protective layer on the image. When the lamination energy (printing energy supplied from the printing unit 40) is increased when forming the protective layer, the protective layer surface becomes a matte tone with low glossiness, and when the lamination energy is decreased, the protective layer surface becomes a glossy tone with high glossiness.

A feed roller 9a which is rotatably driven for carrying the print sheet 7 and a pinch roller 9b for pressing the print sheet 7 against the feed roller 9a are formed on the upstream side of the thermal head 1.

The ink ribbon 5 has a Y layer 51, an M layer 52, a C layer 53, and an OP layer 54 formed on the surface of the base material layer on the side of in this order from the ribbon recovery section 4 side, in other words, 1 set ( screen sizes) of the ink layers 50 including the Y layer 51, the M layer 52, the C layer 53, and the OP layer 54 is provided in series, and the dimensions of the Y layer 51, the M layer 52, and the C layer 53 are slightly larger than the dimensions of screen size images formed on the print sheet 7.

As the Y layer 51, the M layer 52, and the C layer 53, a material in which a sublimation dye is melted or dispersed on a binder resin is preferably used. As the OP layer 54, a material which is transparent and has adhesiveness, light resistance, and the like is preferably used.

The base material layer is a layer for supporting the ink layer 50, and a conventionally known layer having a certain degree of heat resistance and strength can be used. For example, a polyethylene terephthalate film, a polyethylene naphthalate film, a polystyrene film, a polypropylene film, a polycarbonate film, or the like may be mentioned.

The thermal head 1 heats the ink ribbon 5 from the back layer side, the back layer improves heat resistance to prevent the deformation of the ink ribbon 5 due to heat during heat transfer, and improves the traveling property of the thermal head 1 during heat transfer to suppress adhesion and the like, and in the case of , a material to which a slip agent, a surfactant, inorganic particles, organic particles, a pigment and the like are added is applied to a binder resin and dried to form a back layer.

The printing sheet 7 is wound around the printing roller 6 and is drawn out from the printing roller 6. As the print sheet 7, a known print sheet can be used. The print sheet 7 is drawn out (conveyed forward) and wound up (conveyed backward) by a drive unit 30 including a print roller 6, a feed roller 9a, and a pinch roller 9 b.

The printing sheet 7 on which the image formation and the resist delamination are performed by the printing unit 40 is cut into printing sheets 7a by the paper cutting unit 8 on the downstream side. The printing sheet 7a is discharged from a discharge port not shown.

A sensor 20 for detecting the ink content of a Y layer 51, an M layer 52 and a C layer 53 of an ink ribbon 5 drawn from the ink ribbon supply unit 3 is provided between the thermal head 1 and the ink ribbon supply unit 3. for example, the sensor 20 has a light emitting unit 21 for emitting light to the ink ribbon 5 (the Y layer 51, the M layer 52 and the C layer 53) and a light receiving unit 22 for receiving transmitted light transmitted through the ink ribbon 5. the light receiving intensity in the light receiving unit 22 is weaker as the ink content of the ink ribbon 5 is larger, and the light receiving intensity in the light receiving unit 22 is larger as the ink content of the ink ribbon 5 is smaller, and is larger as the ink content of the ink ribbon 5 is smaller.

A plurality of light emitting sections 21 are provided for emitting light having wavelengths suitable for the colors of the Y layer 51, the M layer 52, and the C layer 53.

The storage unit 12 is a hard disk device, a flash memory, or the like, and stores a table in which energy to be applied by the thermal head 1 is specified in order to print an image of a desired density. This table is prepared for each ink content of the ink ribbon 5, and Y, M, C constitutes a set.

The control unit 10 controls driving of each unit of the thermal transfer printing apparatus to perform an image forming process. The control unit 10 obtains the light reception intensity from the light receiving unit 22, and takes out a table corresponding to the light reception intensity (the ink content of the ink ribbon 5) from the storage unit 12. The control unit 10 controls the energy applied to the thermal head 1 during image formation by referring to the extracted table.

The thermal transfer printing method according to the present embodiment will be described with reference to a flowchart shown in fig. 3. The thermal transfer printer is powered on (step S1), and when a new ink ribbon 5 is attached (step S2), the thermal transfer printer performs an initial operation. In this initial operation, the ink ribbon 5 is wound up and rewound.

At this time, the sensor 20 irradiates light to the Y layer 51, the M layer 52, and the C layer 53 of the th group of ink layers 50 to measure the ink content (step S3).

For example, the control unit 10 calculates an average of the received light intensities of the transmitted light of the Y layer 51, the M layer 52, and the C layer 53. If the calculation result is 1 st predetermined value a or more and 2 nd predetermined value b or less (yes at step S4), table 1 is selected from storage unit 12 (step S6).

If the calculation result is less than the 1 st predetermined value a (no at step S4, yes at step S5), the controller 10 selects the 2 nd table from the storage unit 12 (step S7).

If the calculation result is greater than the 2 nd predetermined value b (no at step S4, no at step S5), the controller 10 selects the 3 rd table from the storage unit 12 (step S8).

After the table is selected, the printing process is performed (step S9). In the printing process, first, the print sheet 7 and the Y layer 51 are aligned, and the thermal head 1 is brought into contact with the platen roller 2 via the print sheet 7 and the ink ribbon 5. Then, the feed roller 9a and the ink ribbon recovery unit 4 are rotationally driven to feed the print sheet 7 and the ink ribbon 5 to the rear side. During this time, the areas of the Y layer 51 are selectively heated in sequence by the thermal head 1 according to the image data, and Y is sublimation-transferred from the ink ribbon 5 onto the print sheet 7.

After sublimation transfer Y, the thermal head 1 ascends to be separated from the platen roller 2. Next, the print sheet 7 and the M layer 52 are aligned. In this case, the print sheet 7 is moved forward by a distance corresponding to the print size, and the ink ribbon 5 is moved backward by a distance corresponding to the edge between the Y layer 51 and the M layer 52.

Similarly to the sublimation transfer method Y, the images M and C are sequentially sublimation transferred onto the print sheet 7 based on the image data, and the images are formed on the print sheet 7. The controller 10 controls the energy applied to the thermal head 1 at the time of Y, M, C transfer with reference to the table selected in steps S6 to S8. The print processing is performed with reference to the same table until the power of the thermal transfer printing apparatus is turned off.

After the image is formed, the OP layer 54 is transferred on the entire image by the thermal head 1 and a protective layer is formed. Thereafter, the printing sheet 7 is cut into printing sheets 7a on the downstream side by the cutter 8.

In this way, in the present embodiment, the ink content of the ink ribbon 5 loaded in the thermal transfer printing apparatus is measured, and sublimation transfer of the Y layer 51, the M layer 52, and the C layer 53 is performed in accordance with the application energy corresponding to the measurement result to print an image. Therefore, regardless of the ink content of the ink ribbon 5, the quality of the printed image can be stabilized.

In the above embodiment, the example in which the table in the storage unit 12 is selected based on the average value of the received light intensities of the transmitted lights of the Y layer 51, the M layer 52, and the C layer 53 has been described, but when the table of each color is prepared for each received light intensity, the table of each color may be selected based on the received light intensity of the transmitted light of each of the Y layer 51, the M layer 52, and the C layer 53.

The reception intensities of transmitted light of any colors or two colors of the Y layer 51, the M layer 52, and the C layer 53 are measured, and a table constituting the YMC set is selected based on the measurement results.

In the above embodiment, the measurement of the ink content and the selection of the table were performed when a new ink ribbon 5 was attached after the power supply was turned on, but the measurement of the ink content and the selection of the table may be performed every hours, for example, the measurement of the ink content and the selection of the table may be performed every days, times, and at predetermined times.

[ 2 nd embodiment ]

In the ink ribbon 5 provided with a plurality of ink layers 50 in the above-described embodiment 1, the ink content of the ink layer 50 of the th group (leading end) is measured to select a table, and the same table is applied to the subsequent ink layer 50, but the ink content of the ink layer 50 of each group may be measured to select a table, and the selected table may be applied to the printing process using the ink layer 50 of the next group.

If there is a selected table (yes at step S11), the process proceeds to step S13. if there is no selected table (no at step S11), that is, if the th group of ink layers 50 are used, a standard table in which the print image density and the standard application energy are specified is selected (step S12).

The conveyance of the ink ribbon 5 is started, the ink ribbon 5 is drawn out by the ribbon supply unit 3, and the ink ribbon 5 is wound by the ribbon recovery unit 4 (step S13).

Before the print sheet 7 and the Y layer 51 are sandwiched between the thermal head 1 and the platen roller 2, the sensor 20 irradiates light to the Y layer 51 to measure the received light intensity (step S14). The thermal head 1 controls the application of energy according to the selected table to heat the Y layer 51 and sublimation-transfer Y from the ink ribbon 5 onto the print sheet 7 (step S15).

Before the print sheet 7 and the M layer 52 are sandwiched between the thermal head 1 and the platen roller 2, the sensor 20 irradiates light to the M layer 52 to measure the received light intensity (step S16). The thermal head 1 controls the application of energy according to the selected table to heat the M layer 52, and sublimation-transfers M from the ink ribbon 5 onto the print sheet 7 (step S17).

Before the print sheet 7 and the C layer 53 are sandwiched between the thermal head 1 and the platen roller 2, the sensor 20 irradiates light to the C layer 53 to measure the received light intensity (step S18). The thermal head 1 controls the application of energy according to the selected table to heat the C layer 53 and sublimation-transfer C from the ink ribbon 5 onto the print sheet 7 (step S19).

The OP layer 54 is transferred onto the image formed on the print sheet 7 (step S20). Thereafter, the printing sheet 7 is cut into printing sheets 7a on the downstream side by the cutter 8.

The control unit 10 calculates the average of the received light intensities of the transmitted light of the Y layer 51, the M layer 52, and the C layer 53 measured in steps S14, S16, and S18. If the calculation result is 1 st predetermined value a or more and 2 nd predetermined value b or less (yes at step S21), table 1 is selected from storage unit 12 (step S23).

If the calculation result is less than the 1 st predetermined value a (no at step S21, yes at step S22), the controller 10 selects the 2 nd table from the storage unit 12 (step S24).

If the calculation result is greater than the 2 nd predetermined value b (no at step S21, no at step S22), the controller 10 selects the 3 rd table from the storage unit 12 (step S25).

When there are printed images (step S26 — yes), the application of energy is controlled in accordance with the table selected in steps S23 to S25 to perform the printing process.

In this way, even when the table is selected from the measurement results of the ink content of the ink layer 50 before 1 set and the application energy in the printing process is controlled, the image quality of the printed image is stabilized regardless of the ink content of the ink ribbon 5.

In the present embodiment, the table of each color may be selected based on the received light intensity of each of the transmitted light beams of the Y layer 51, the M layer 52, and the C layer 53, and the received light intensity of any colors or two colors of the transmitted light beams of the Y layer 51, the M layer 52, and the C layer 53 may be measured, and the table constituting the YMC set may be selected based on the measurement result.

In the present embodiment, the applied energy during the printing process is controlled by selecting the table from the measurement results of the ink content of the ink layer 50 before 1 set, but the table selected from the measurement results of the ink content of the ink layer 50 may be directly applied to the printing process using the same set of ink layers 50.

[ embodiment 3 ]

Fig. 5 is a schematic configuration diagram of the thermal transfer printing apparatus according to embodiment 3, and in this embodiment, there is a difference at point in that the sensor 20 is provided between the thermal head 1 and the ribbon recovery unit 4, as compared with embodiment 1 shown in fig. 1, and the same configuration as that of embodiment 1 will not be described.

In the present embodiment, the sensor 20 detects the ink content of the Y layer 51, the M layer 52, and the C layer 53 of the used ink ribbon 5 wound around the ribbon recovery unit 4 after the printing process is performed in the printing unit 40.

As described above, the Y layer 51, the M layer 52, and the C layer 53 are slightly larger in size than the size of the screen-sized images formed on the printing sheet 7, and therefore, the peripheral portions of the Y layer 51, the M layer 52, and the C layer 53 after the printing process become unprinted areas that are not used in the printing process, and ink remains unused, and indicates that ink is shifted to the printing sheet 7 side in the image printing process in a printing area located on the inner side of the unprinted areas and an amount of ink corresponding to the printing density remains.

The sensor 20 irradiates light to the printed area and the unprinted area, and measures the ink content (residual amount). The difference between the light reception intensity when the unprinted area is irradiated with light and the light reception intensity when the printed area is irradiated with light corresponds to the amount of ink (ink transfer amount) actually transferred to the printing sheet 7.

The amount of ink transferred to the printing sheet 7 varies depending on the storage environment until the ink ribbon 5 is mounted on the thermal transfer printing apparatus and the installation environment (temperature and humidity) of the thermal transfer printing apparatus, and thus a difference occurs in the image quality of an image. In the present embodiment, the ink transfer amount is determined from the difference in the ink remaining amount between the print area and the unprinted area, and a table in which an image of a desired image quality can be printed with a desired ink transfer amount is selected.

The storage unit 12 stores difference prediction value information in which the difference between the energy at the time of image printing and the light reception intensity predicted when printing is performed using the energy is correlated with each other. The difference prediction value information is prepared for each color Y, M, C. The difference prediction value information may be prepared for each received light intensity when the unprinted area is irradiated with light. The control unit 10 compares the difference of the measured light reception intensities (actually measured value of difference) with the difference of the light reception intensities (predicted value of difference) based on the predicted value information of difference, and selects a table based on the comparison result.

The thermal transfer printing method according to the present embodiment will be described with reference to a flowchart shown in fig. 7.

If there is a selected table (yes at step S101), the flow proceeds to step S103. if there is no selected table (no at step S101), that is, if the ink layer 50 of group is used, a standard table specifying the print image density and the standard application energy is selected (step S102).

The conveyance of the ink ribbon 5 is started, the ink ribbon 5 is drawn out by the ribbon supply unit 3, and the ink ribbon 5 is wound by the ribbon recovery unit 4 (step S103).

The thermal head 1 controls the application of energy according to the selected table to heat the Y layer 51, thereby sublimation-transferring Y from the ink ribbon 5 onto the print sheet 7 (step S104).

The sensor 20 irradiates light to the unprinted area of the Y layer 51 after the printing process to measure the received light intensity (step S105). The sensor 20 irradiates light to the print area of the Y layer 51 after the print processing to measure the received light intensity (step S106). The average of the light reception intensity may be obtained by irradiating light to a plurality of positions in the print area, or the entire print area may be irradiated with light. Further, the light may be irradiated to a portion to which a predetermined energy is applied during the printing process.

The thermal head 1 controls the application of energy according to the selected table to heat the M layer 52, sublimation-transfer M from the ink ribbon 5 onto the print sheet 7 (step S107).

The sensor 20 irradiates light to the unprinted area of the M layer 52 after the printing process to measure the received light intensity (step S108). The sensor 20 irradiates light to the print area of the M layer 52 after the print processing to measure the received light intensity (step S109).

The thermal head 1 controls the application of energy according to the selected table to heat the C layer 53, and sublimation transfers C from the ink ribbon 5 onto the print sheet 7 (step S110).

The sensor 20 irradiates light to the unprinted area of the C layer 53 after the printing process to measure the received light intensity (step S111). The sensor 20 irradiates light to the print area of the C layer 53 after the print processing to measure the received light intensity (step S112).

The OP layer 54 is transferred onto the image formed on the print sheet 7 (step S113). Thereafter, the printing sheet 7 is cut into printing sheets 7a on the downstream side by the cutter 8.

The control unit 10 calculates the difference between the light reception intensities measured in steps S105 and S106 (step S114). This difference corresponds to the ink transfer amount of Y. Similarly, the control unit 10 calculates the difference between the light reception intensities measured in steps S108 and S109. The difference corresponds to the ink transfer amount of M. Further, the control unit 10 calculates the difference between the light reception intensities measured in steps S111 and S112. This difference corresponds to the ink transfer amount of C.

The control unit 10 obtains Y, M, C predicted values of the difference in light reception intensity from the difference predicted value information stored in the storage unit 12 and the image data at the time of the printing process (step S115).

The control unit 10 compares the actually measured value of the difference in light reception intensity calculated in step S114 with the predicted value of the difference in light reception intensity obtained in step S115 for Y, M, C, and selects a table based on the comparison result (for example, the degree of divergence between the actually measured value and the predicted value) (step S116).

If there are printed images (yes at step S117), the application of energy is controlled in accordance with the table selected at step S116, and the printing process is performed.

In this way, by selecting a table from the measurement results of the ink transfer amounts of the ink layers 50 before 1 set and controlling the energy applied during the printing process, the image quality of the printed image can be stabilized regardless of the storage environment of the ink ribbon 5 and the installation environment of the thermal transfer printing apparatus.

In this embodiment, the difference in received light intensity of any colors or two colors of the Y layer 51, the M layer 52, and the C layer 53 is measured, and a table set is selected based on the measurement result.

[ 4 th embodiment ]

In embodiment 3 described above, the difference in received light intensity between the print area and the unprinted area of the Y layer 51, the M layer 52, and the C layer 53 after the printing process is obtained, but the table may be selected according to the received light intensity ratio.

In the case where the difference in light reception intensity between the printed area and the unprinted area is obtained, the component of the attenuation caused by the back layer is excluded, and in other , the light reception intensity ratio is determined to be a more accurate value by taking into account the influence of the attenuation caused by the back layer.

Therefore, in the present embodiment, light is also irradiated to the transparent OP layer 54, and the light attenuation amount x by the back layer is calculated from the light intensity received. Then, the ratio (y-x)/(z-x) between the value obtained by subtracting the light attenuation amount x from the received light intensity y when the unprinted area is irradiated and the value obtained by subtracting the light attenuation amount x from the received light intensity z when the printed area is irradiated is calculated as the received light intensity ratio.

The thermal transfer printing method according to the present embodiment will be described with reference to a flowchart shown in fig. 8. Steps S201 to S213 are the same as steps S101 to S113 of the flowchart shown in fig. 7, and therefore, the description thereof is omitted.

After the transfer of the OP layer 54, the sensor 20 irradiates light to the region (protective layer forming region) where the OP layer 54 of the ink ribbon 5 is formed and measures the received light intensity (step S214).

The control unit 10 calculates the amount x of light attenuation by the back layer from the measurement result of the protective layer forming region. Then, the control unit 10 calculates a ratio of the light attenuation amount x subtracted from the received light intensity measured in steps S205 and S206 (step S214). This ratio corresponds to the ink transfer amount of Y. Similarly, the control unit 10 calculates a ratio of the light attenuation amount x subtracted from the received light intensity measured in steps S208 and S209. This ratio corresponds to the ink transfer amount of M. Further, the control unit 10 calculates a ratio of a value obtained by subtracting the light attenuation amount x from the received light intensity measured in steps S211 and S212. This ratio corresponds to the ink transfer amount of C.

The control unit 10 calculates Y, M, C an average value of the ratio of the received light intensities. If the calculation result is not less than the 5 th predetermined value e but not more than the 6 th predetermined value f (step S216 — yes), the 1 st table is selected from the storage unit 12 (step S218).

If the calculation result is less than the 5 th predetermined value e (no at step S216, yes at step S217), the control unit 10 selects the 2 nd table from the storage unit 12 (step S219).

If the calculation result is greater than the 6 th predetermined value f (no at step S216, no at step S217), the control unit 10 selects the 3 rd table from the storage unit 12 (step S220).

If there are printed images (step S221 — yes), the application of energy is controlled based on the table selected in steps S218 to S220, and the printing process is performed.

In this way, even when the table is selected based on the light receiving intensity ratio indicating the ink transfer amount of the ink layer 50 before 1 set and the application energy in the printing process is controlled, the image quality of the printed image can be stabilized regardless of the storage environment of the ink ribbon 5 or the installation environment of the thermal transfer printing apparatus.

In the present embodiment, the table of each color is selected based on the ratio of the received light intensities of the printed area and the unprinted area of each of the Y layer 51, the M layer 52, and the C layer 53, and the ratio of the received light intensities of any colors or two colors of the Y layer 51, the M layer 52, and the C layer 53 is measured, and the table constituting the YMC set is selected based on the measurement result.

In the above embodiment, an example was described in which any tables among 3 types of tables are selected from the measurement results of the received light intensity, but any tables among 4 or more types of tables may be selected by increasing the boundary value.

In the case where a plurality of types of ink ribbons 5 can be mounted in the thermal transfer printing apparatus, the storage unit 12 can store the boundary values (the 1 st to 6 th predetermined values a to f) and the table for each type of ink ribbon 5. A barcode or the like for identifying the type is added to the ink ribbon 5, and the thermal transfer printer reads the barcode to identify the type of the ink ribbon 5 installed, and uses the corresponding boundary value and table.

In the above embodiment, the configuration in which the light emitting portion 21 and the light receiving portion 22 that measures the received light intensity of the transmitted light are provided as the sensor 20 that detects the ink content of the ink ribbon 5 has been described, but the configuration of the sensor 20 is not limited to this. For example, the sensor 20 may have imaging means such as a digital camera, and image-captures the Y layer 51, the M layer 52, and the C layer 53, and detects the degree of ink contained from the captured image.

The sensors 20 may be provided between the ribbon supply unit 3 and the thermal head 1 and between the thermal head 1 and the ribbon recovery unit 4.

The sensor 20 can be used for counting the number of printed pictures, or for starting the ink ribbon 5.

In the above-described embodiments 1 to 3, the ink ribbon 5 in which the OP layer 54 is omitted may be used. In this case, the protective layer may be formed on the image using the picture protective tape provided with the OP layer 54 alone. For example, a protective layer forming section in which a supply roller for supplying the screen protective tape, a recovery roller for recovering the screen protective tape, a thermal head for thermally transferring a protective layer on an image, and the like are formed is provided on the downstream side of the printing section 40 (which may be the downstream side of the paper cutting section 8).

The present invention is not limited to the above-described embodiments, and constituent elements may be modified and embodied in the implementation stage within a range not departing from the gist thereof. Further, a plurality of constituent elements disclosed in the above embodiments may be appropriately combined to form various inventions. For example, several constituent elements may be deleted from all the constituent elements shown in the embodiments. Further, the constituent elements in the different embodiments may be appropriately combined.

The present application is applied based on japanese patent application 2017-129282, applied on 30/6/2017, the entire contents of which are incorporated herein by reference.

Description of the symbols

1 thermal head

2 embossing roll

3 ink ribbon supply part

4 ribbon recovery part

5 ink ribbon

7 printing sheet

10 control part

12 storage part

20 sensor

40 printing part

50 ink layer