阅读说明：本技术 织物印刷方法和织物印刷设备 (Fabric printing method and fabric printing apparatus ) 是由 一之濑孝一 土肥克己 于 2018-06-20 设计创作，主要内容包括：提供了一种织物印刷方法和织物印刷设备,利用该设备,当通过点印刷将设计或背景印刷在织物的前表面上时,能够从后表面看到印刷在织物前表面上的字符、图画或背景,并且前表面不太可能显示颗粒感。该织物印刷方法包括：多个第一油墨罐53,多种印刷色的油墨分别填充在其中；至少一个第二油墨罐54,通过混合不同印刷色的油墨而获得的至少一种专色油墨填充在其中。在待印刷的织物上进行印刷,该待印刷的织物被划分成建立在第一表面上的多个印刷区域,其包括一个或多个第一印刷区域R1和一个或多个第二印刷区域R2,在第一印刷区域中,用从第一油墨罐中的至少一个引入的油墨印刷点,在第二印刷区域中,用从第二油墨罐中的至少一个引入的油墨印刷点。(Provided are a fabric printing method and a fabric printing apparatus with which, when a design or background is printed on a front surface of a fabric by dot printing, characters, drawings, or the background printed on the front surface of the fabric can be seen from a rear surface, and the front surface is less likely to show a grainy feeling. The fabric printing method comprises the following steps: a plurality of first ink tanks 53 in which a plurality of printing color inks are filled, respectively; at least one second ink tank 54 in which at least one spot color ink obtained by mixing inks of different process colors is filled. Printing is performed on a fabric to be printed, which is divided into a plurality of printing areas established on the first surface, including one or more first printing areas R1 in which dots are printed with ink introduced from at least one of the first ink tanks, and one or more second printing areas R2 in which dots are printed with ink introduced from at least one of the second ink tanks.)

1. A method of fabric printing comprising:

a plurality of first ink tanks filled with inks of a plurality of printing colors, respectively; and

at least one second ink tank filled with at least one spot color ink obtained by mixing inks of different process colors,

the method includes performing printing on a fabric to be printed by dividing a plurality of printing areas provided on a first side of the fabric into one or more first printing areas in which dots are printed with ink introduced from at least one of the first ink tanks and one or more second printing areas in which dots are printed with ink introduced from the at least one second ink tank.

2. The fabric printing method according to claim 1, wherein an area ratio per unit area of the dots formed by the spot color ink is not less than 80% and not more than 100%.

3. The fabric printing method according to claim 1 or 2, wherein a design pattern having at least one of a drawing and a character is printed as dots in the first printing area using the ink introduced from the first ink tank, and a background of the design pattern is printed as dots in the second printing area using the ink introduced from the second ink tank.

4. A fabric printing apparatus as claimed in claim 1 or 3, wherein the fabric to be printed is a fabric for an item of apparel.

5. A fabric printing apparatus comprising:

a plurality of first ink tanks filled with inks of a plurality of printing colors, respectively;

at least one second ink tank filled with at least one spot color ink obtained by mixing inks of different process colors;

a plurality of first printing heads which are respectively connected to the plurality of first ink tanks and perform printing of dots in one or more first printing regions provided on a first side of the fabric to be printed with the ink of the printing color; and

at least one second print head connected to the at least one second ink tank and performing printing of dots in one or more second print areas disposed on the first side of the fabric to be printed with spot color ink.

6. The fabric printing apparatus of claim 5, further comprising a deployment device, the deployment device comprising: an ink storage tank that stores inks of a plurality of printing colors, respectively; and a mixing tank that is connected to the ink storage tank and mixes the inks of the different process colors stored in the ink storage tank,

wherein the mixing tank is connected to the at least one second ink tank.

Technical Field

The present invention relates to a fabric printing method and a fabric printing apparatus, and more particularly, to a fabric printing method and a fabric printing apparatus that perform printing with a printing color ink and perform printing with a spot color ink.

Background

In recent years, printing using a combination of printing colors such as CMYK (cyan, magenta, yellow, and black) has been performed. This type of printing is called "process color printing". For example, an inkjet printing apparatus disclosed in patent document 1 has been proposed. In the inkjet printing apparatus, transfer rollers are provided upstream and downstream, and a transfer belt for transferring a fabric is wound around the transfer rollers. The fabric is conveyed by a conveyor belt and printing is performed with printing color ink supplied from a printing head.

In this type of inkjet printing apparatus, printing is typically performed by dot printing. The dot printing creates dots, and adjusts the interval between dots, the size of the corresponding dots, and the overlapping state of the dots of the respective colors, thereby expressing the variation and density of colors. This printing method enables reproduction of various colors.

For example, as shown in fig. 7(a) to 7(C), the dot printing expresses various degrees of color density by adjusting the dot area per unit area (area ratio). The color density increases with increasing dot density. Fig. 7(C) shows an example in which the dot area ratio is 10%, in which the color to be expressed is a light color. Fig. 7(a) shows an example in which the dot area ratio is 100%, in which the color to be expressed is a dark color. Fig. 7(B) shows an example in which the dot area ratio is 50%, in which the density of colors to be expressed is in the middle of fig. 7(a) and 7 (C). It follows that the higher the dot area ratio, the darker the color to be expressed.

Reference list

Patent document

Patent document 1: japanese patent No.5116542

Disclosure of Invention

Technical problem

For example, when printing is performed on a fabric such as chiffon or twill to be used for clothing such as a scarf, it is preferable that ink penetrate to the back side of the fabric (this phenomenon may also be referred to as "penetration") so that characters, drawings, and a background printed on the surface can be seen from the back side of the fabric. This is because, when articles of apparel such as scarves are used, they are recognized not only from the surface but also from the back.

However, when a light color is printed on a fabric by dot printing, the dot area ratio becomes small, and the area where no dot is printed is large. Thus, if the ink in the front surface does not sufficiently penetrate to the back surface, the original color (e.g., white) of the fabric will be recognized as the color of the back surface. For example, when yellow is printed on the surface of a white fabric with a small dot area ratio, as shown in fig. 8(a), although yellowish printing is visible on the fabric surface, the ink for printing dots does not penetrate to the back surface, and thus the back surface is recognized substantially as white, as shown in fig. 8 (B).

Further, when dot printing is performed using inks of a plurality of printing colors, dots may protrude on the surface according to the area ratio of the dots of the respective colors, thus resulting in a problematic grainy appearance as shown in fig. 9.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a fabric printing method and a fabric printing apparatus, which are capable of performing printing while ensuring that characters, drawings, and backgrounds printed on a fabric surface are visible from the back side of the fabric and reducing the appearance of grainy appearance on the fabric surface when a design pattern and a background are printed on the fabric surface by dot printing.

Solution to the problem

A method of printing a fabric according to some embodiments of the present invention comprises: a plurality of first ink tanks filled with inks of a plurality of printing colors, respectively; and at least one second ink tank filled with at least one spot color ink obtained by mixing inks of different printing colors, the method including performing printing on the fabric by dividing a plurality of printing areas provided on a first face of the fabric to be printed into one or more first printing areas in which dots are printed with the ink introduced from at least one of the first ink tanks and one or more second printing areas in which dots are printed with the ink introduced from at least one of the second ink tanks.

With this structure, since printing is performed in the second printing region using spot color ink obtained by mixing a plurality of printing color inks, the dot area ratio is increased to be larger than the case of using the printing color inks while performing printing. Thus, the ink in the first side (i.e., surface) penetrates into the second side (i.e., back) of the fabric, allowing characters, drawings, and background printed on the surface of the fabric to be viewed from the back. In addition, since the dot area is large, a grainy appearance is not easily seen.

Further, in the first printing region, so-called "printing color printing" using a printing color ink or a combination of a plurality of printing color inks is performed. This makes it possible to express and refine designs of various colors.

In a preferred embodiment, the area ratio per unit area of the dots formed by the spot color ink is not less than 80% and not more than 100%.

With this structure, since the area of dots per unit area is relatively large when printed on the fabric surface, the ink on the fabric surface penetrates to the back surface, allowing characters, pictures and backgrounds printed on the fabric surface to be seen from the back surface and reducing the occurrence of grainy appearance on the surface.

The area ratio is preferably not less than 90% and not more than 100%, and more preferably 100%.

In a preferred embodiment, in the first printing region, a design pattern having at least one of a drawing and a character is printed as dots with ink introduced from the first ink tank, and in the second printing region, a background of the design pattern is printed as dots with ink introduced from the second ink tank.

The background of the design pattern typically has a larger print area than the pattern. Therefore, when the process color printing is used for the background printing, the back surface is recognized as white, and the grainy appearance exists in the surface. The white and grainy appearance of the back surface is undesirably prominent. In the present invention, in the first printing region, the patterns of the respective colors are expressed by printing color, and the background of the patterns is printed in the second printing region using spot color ink. Therefore, the whiteness of the back surface or the grainy appearance of the surface is not prominent.

In a preferred embodiment, the fabric to be printed is a fabric for an article of apparel.

The fabric for the clothing accessories is, for example, a fabric for a scarf, a handkerchief, a shawl, or the like, in which characters, pictures, and backgrounds printed on the surface of the fabric are preferably visible from the back side.

A fabric printing apparatus according to some embodiments of the present invention comprises: a plurality of first ink tanks filled with inks of a plurality of printing colors, respectively; at least one second ink tank filled with at least one spot color ink obtained by mixing inks of different process colors; a plurality of first printing heads which are respectively connected to the plurality of first ink tanks and perform printing of dots in one or more first printing regions provided on a first side of the fabric to be printed with the ink of the printing color; and at least one second printing head connected to the at least one second ink tank and performing printing of dots in one or more second printing areas provided on the first side of the fabric to be printed with spot color ink.

Spot color ink is supplied from a second ink tank to a second print head, and dots are printed by the first print head in a first print zone on a first side (i.e., surface) of the web. In the second printing area, printing is performed using spot color ink obtained by mixing a plurality of printing color inks while increasing the dot area ratio to be larger than the case of using the printing color inks. Therefore, the ink in the surface penetrates to the second side (i.e., the back side) of the fabric, thereby allowing characters, drawings, and backgrounds printed on the surface of the fabric to be visible from the back side, and a grainy appearance is not easily seen.

Further, printing ink is supplied from a first ink tank to the first print head, and dots are printed in the first print area by the first print head. In the first printing area, so-called "print color printing" using a print color ink or a combination of a plurality of print color inks is performed. This makes it possible to express and design various colors.

One embodiment of the present invention also includes a blending device, comprising: an ink storage tank that stores inks of a plurality of printing colors, respectively; and a mixed ink storage container that is connected to the ink storage tank and stores mixed ink obtained by mixing inks of different process colors introduced from the ink storage tank. The mixed ink storage container is connected to at least one second ink tank.

With this structure, since the spot color ink is prepared by color blending by the blending device and is introduced into the second ink tank, it is possible to easily prepare a desired spot color ink by color blending and supply the ink into the second ink tank.

Advantageous effects of the invention

The present invention enables the back side of the fabric to be penetrated with ink in the surface, allowing characters, drawings and background printed on the fabric surface to be seen from the back side.

Drawings

Fig. 1 is a schematic view showing the overall structure of a fabric printing apparatus according to one embodiment of the present invention.

Fig. 2 is an explanatory diagram showing an ink flow supplied to the first print head.

Fig. 3 is an explanatory diagram showing an ink flow supplied to the second print head.

Fig. 4 is a schematic diagram showing the structure of the deployment apparatus.

Fig. 5 is an explanatory view showing an example of printing on the fabric surface.

Fig. 6 is an explanatory view showing the second print area. (A) Showing the surface of the second printed area in the fabric and (B) showing the back side thereof.

Fig. 7 is an explanatory diagram showing dot printing. (A) An example in which the dot area per unit area is 10% is shown, (B) an example in which the dot area per unit area is 50% is shown, and (C) an example in which the dot area per unit area is 100% is shown.

Fig. 8 shows the (a) surface and (B) backside of the fabric when printed at a low dot area ratio.

Fig. 9 shows a state of printing in which a grainy appearance exists.

Detailed Description

Hereinafter, embodiments of the present invention are described by referring to the drawings.

Fig. 1 is an explanatory diagram showing the overall structure of a fabric printing apparatus 10 according to an embodiment of the present invention, and fig. 2 is an explanatory diagram showing an ink flow when ink is supplied to a first print head 51. Fig. 3 is an explanatory diagram showing an ink flow when ink is supplied to the second printing head 52.

The fabric printing apparatus 10 includes a printing apparatus main body 20, an ink supply device 30, an ink formulating device 40, and a control device (not shown). The printing apparatus main body 20 includes a support 21, a conveying belt 22 for conveying the fabric C, and a driven roller 23A (upstream) and a driving roller 23B (downstream) attached to the support 21 for running the conveying belt 22. Above the upstream driven roller 23A, a bonding device 24 for bonding the fabric C to the conveying belt 22 with an adhesive or the like is provided, and below the downstream driving roller 23B, a belt washing device 25 for washing off the pulp or ink remaining on the conveying belt 22 is provided.

The print head carrying unit 50 is disposed above the conveyor belt 22 between the drive roller 23B and the driven roller 23A.

The print head carrying unit 50 is supported by a unit supporting mechanism 26 attached to the upper surface of the support 21. A unit moving mechanism (not shown) reciprocally moves the print head carrying unit 50 in a direction perpendicular to the conveying direction of the fabric C.

The print head carrying unit 50 includes a plurality of first print heads 51, a first negative pressure ink tank 53 in the same number as the first print heads 51, at least one second print head 52, a second negative pressure ink tank 54 in the same number as the second print head 52, and a degassing module 55 in the same number as the total number of the first print heads 51 and the second print heads 52.

Each first print head 51 is connected to each first negative-pressure ink tank 53 through each degassing module 55 with a pipe. The first negative-pressure ink tanks 53 are filled with inks of a plurality of printing colors, respectively, and the inks in the respective first negative-pressure ink tanks 53 are supplied to the respective first print heads 51, respectively. Each first print head 51 has nozzles. The nozzles discharge the printing color ink toward the fabric C and print dots in one or more first printing regions R1 (see fig. 5) provided on the first side (i.e., surface) of the fabric C to be printed. The degassing module 55 is used to remove gas contained in the ink.

At least one second print head 52 is piped through each degassing module 55 to at least one second negative pressure ink tank 54. The at least one second negative-pressure ink tank 54 is filled with at least one spot color ink obtained by mixing inks of different process colors. The ink in at least one second negative pressure ink tank 54 is supplied to at least one second print head 52. The second print head 52 has nozzles. The nozzles discharge ink of the printing color toward the fabric C and print dots in one or more second printing areas R2 (see fig. 5) provided on the surface of the fabric C to be printed.

In this embodiment, twelve first print heads 51, twelve second print heads 52, twelve first negative pressure ink tanks 53 and 54, and twenty-four degassing modules 55 are provided; however, the number of these components is not limited to these numbers.

It is also possible to fill some of the plurality of first negative-pressure ink tanks 53 with a penetrant instead of ink, and to cause the penetrant to be discharged while printing dots on the fabric C.

In the printing apparatus main body 20 of fig. 1, only one first printing head 51, one second printing head 52, two degassing modules 55, one first negative-pressure ink tank 53, and one second negative-pressure ink tank 54 are shown. The remaining first print head 51, second print head 52, degassing module 55, and first and second negative- pressure ink tanks 53 and 54 are omitted in fig. 1. The tubes for connecting the corresponding structures are also omitted in fig. 1. Furthermore, fig. 2 shows the ink flow supplied to a first print head 51, and fig. 3 shows the ink flow supplied to a second print head 52. The configuration of supplying ink to the other first print heads 51 and the other second print heads 52 is the same as that shown in fig. 2 and 3, and illustration and explanation thereof are omitted.

In the present specification, "printing color" refers to the color of the ink supplied to the first print head 51.

Further, "spot color" refers to the color of ink supplied to the second print head 52 obtained by mixing inks of different process colors.

As shown in fig. 1, the ink supply device 30 includes, in a housing 301, a first main ink tank 31 and a second main ink tank 32, a first ink sub-tank 33 and a second ink sub-tank 34, a first ink supply pump 35 and a second ink supply pump 36, and a vacuum pump 37. In this embodiment, the number of the first and second main ink tanks 31 and 32, the first and second ink sub tanks 33 and 34, and the first and second ink supply pumps 35 and 36 is the same as the number of the first and second negative- pressure ink tanks 53 and 54, that is, 12. In the ink supply device 30 of fig. 1, only one each of the first and second main ink tanks 31 and 32, only one each of the first and second ink sub-tanks 33 and 34, and only one each of the first and second ink supply pumps 35 and 36 are shown, and other structures are omitted. In addition, the tube for connecting structure, the ink collecting tube 39, the ink supplying tube 38, and the degassing module tube 56 are also omitted in the drawing.

As shown in fig. 2, the first main ink tank 31 is connected to the first ink subtank 33 through a pipe, and the first ink subtank 33 is connected to the first negative-pressure ink tank 53 through the ink supply pipe 38. A first ink supply pump 35 is provided in the middle of the ink supply pipe 38 to adjust the supply amount of the printing color ink.

Each first print head 51 is connected to each first ink subtank 33 by an ink collection tube 39. Ink is collected from the first print head 51 into the first ink subtank 33 by opening a pinch valve (not shown) provided in the ink collection tube 39 when cleaning the first print head 51.

As shown in fig. 3, the second main ink tank 32 is connected to the second ink subtank 34 through a pipe, and the second ink subtank 34 is connected to the second negative pressure ink tank 54 through an ink supply pipe 38. A second ink supply pump 36 is provided in the middle of the ink supply pipe 38 to adjust the supply amount of the spot color ink.

Each second print head 52 is connected to each second ink subtank 34 by an ink collection tube 39. Ink is collected from the second print head 52 to the second ink subtank 34 by opening a pinch valve (not shown) provided in the ink collection tube 39 when cleaning the second print head 52.

The vacuum pump 37 is provided in the ink supply device 30, and is connected to each of the degassing modules 55 separately provided in the first print head 51 and the second print head 52 through a degassing module pipe 56. A vacuum pump 37 may alternatively be provided for each degassing module 55.

For example, as shown in fig. 4, the ink formulating device 40 includes a plurality of storage tanks 41 that individually store inks of a plurality of process colors, and a mixed ink storage container (mixing tank) 42 in which the inks introduced from the storage tanks 41 through pipes are stored and mixed by stirring.

A first metering pump (not shown) is provided in an outlet of each storage tank 41, and the ink measured by the first metering pump is introduced into the mixed ink storage container 42. The mixed ink storage container 42 includes mixing means therein, such as rotating blades.

The mixed ink storage container 42 is connected to each of the second ink main tanks 32 of the ink supply device 30 through a pipe (not shown). A second metering pump (not shown) is provided in the outlet of the mixed ink storage container 42, and the mixed ink measured by the second metering pump is introduced into the second main ink tank 32. The operation of the first and second metering pumps is controlled by a control device (not shown).

The ink dispensing device 40 may include a cleaning mechanism for cleaning the mixed ink storage container 42 and tubes.

The structure of the ink preparing device 40 is not limited to the above structure. The ink formulating device 40 may have any structure as long as it can produce mixed ink of a predetermined spot color by mixing the printing color inks stored in the plurality of storage tanks 41. For example, the ink formulating device 40 may be configured such that the same number of mixed ink storage containers 42 as the second main ink tanks 32 are provided and connected to each other by pipes, and such that all the mixed ink storage containers 42 are connected to all the storage tanks 41. A predetermined amount of process color ink stored in each storage tank 41 is introduced into each mixed ink storage container 42 to generate mixed ink of a predetermined spot color, which is then introduced into each second main ink tank 32. Alternatively, the ink formulating device 40 may be configured such that the mixed ink storage container 42 also serves as the second main ink tank 32, and such that the mixed ink storage container 42 is directly connected to the ink subtank.

The ink formulating device 40 may also be configured such that the mixed ink storage container 42 is made removable from a support supporting the mixed ink storage container 42, instead of connecting the mixed ink storage container 42 to each of the second ink main tanks 32 with a pipe, and an operator carries the mixed ink storage container 42 to the vicinity of the printing apparatus main body 20 and pours the mixed ink into each of the second ink main tanks 32.

Further, the fabric printing apparatus 10 may not be provided with the ink formulating device 40. In this case, it may also be arranged such that each of the second main ink tanks 32 of the ink supply device 30 is removable from the support, and when the amount of ink stored in the second main ink tank 32 becomes small, the second main ink tank 32 is replaced with a new second main ink tank 32. In addition, the operator may pour spot color ink into each of the second main ink tanks 32.

The control device comprises a control unit, a storage unit and an interface unit. The control unit is composed of, for example, a CPU, a memory serving as a work area, and the like. The control unit executes a program stored in the storage unit to control the operations of the printing apparatus main body 20, the ink supply device 30, and the ink formulating device 40. The storage unit is composed of, for example, a storage device such as a flash memory or a nonvolatile memory, and stores a program to be executed by the control unit. The memory unit stores data of the color separation print pattern to be printed on the fabric C, including design and background. The interface unit includes an input port for receiving a signal, an output port for transmitting a signal, an analog-to-digital conversion circuit, and the like. The interface unit transmits/receives signals to/from the printing apparatus main body 20, the ink supply device 30, and the ink formulating device 40. The control device sends drive signals to the first and second print heads 51 and 52 and the unit moving mechanism to move the print head carrying unit 50 in a direction perpendicular to the conveyance direction of the fabric C while ejecting the printing color ink and the spot color ink from the nozzles of the first and second print heads 51 and 52. Further, the control means sends drive signals to drive the vacuum pump 37, the first ink supply pump 35 and the second ink supply pump 36 to fill the first print head 51 and the second print head 52 with ink, while driving the downstream drive roller 23B, the joining means 24 and the belt washing means 25 to convey the fabric C. Further, the control device drives the first metering pump of the ink formulating device 40 to measure a predetermined amount of printing ink, causes the mixing means to mix the inks extracted into the mixed ink storage container 42 to thereby generate mixed inks of predetermined colors, and controls the second metering pumps such that the generated mixed inks are introduced into each of the second ink main tanks 32.

Next, referring to fig. 2, the ink flow when each of the first print heads 51 is filled with printing ink is explained.

The ink stored in advance in the first main ink tank 31 is introduced into the first ink subtank 33, and then introduced into the first negative-pressure ink tank 53 through the ink supply pipe 38 by the first ink supply pump 35. The ink introduced from the first negative-pressure ink tank 53 is deaerated by the deaeration module 55 and supplied to the first print head 51 for printing of a dot in the first printing region R1.

Next, referring to fig. 3, the ink flow when each second printing head 52 is filled with spot color ink is explained. The mixed ink (spot color ink) is introduced from the ink formulating device 40 into the second main ink tank 32. Ink is introduced into the second ink subtank 34 and is introduced into the second negative pressure ink tank 54 by the second ink supply pump 36 through the ink supply tube 38. Ink introduced from the second negative pressure ink tank 54 is deaerated by the deaeration module 55 and supplied to the second printing head 52 for printing of dots in the second printing region R2.

A fabric printing method using the fabric printing apparatus 10 is described below.

The fabric C to be printed is also referred to as a textile or fabric, and includes woven fabrics, dyed fabrics, knitted fabrics, and non-woven fabrics. In this embodiment, the fabric C is a fabric for scarves, handkerchiefs, shawl, or the like, which preferably allows the printing on its first face (i.e., surface) to penetrate to its second face (i.e., back). Examples of such fabrics include chiffon and twill. The fabric C is produced by a fabric production method including a step of performing printing on the fabric C by the following fabric printing method.

Fig. 5 shows an example of printing on the surface of the fabric C. A plurality of printing regions are provided on the surface of the fabric C, and the printing regions are divided into a plurality of first printing regions R1 and second printing regions R2. A single first printing region R1 and a plurality of second printing regions R2 may also be provided.

The first printing region R1 is a region where dots are printed by the first printing head 51 using one or more process color inks introduced from the first negative pressure ink tank 53. The area ratio of dots per unit area and the overlapping state of dots of respective colors are adjusted to express the variation and density of colors. The designed pattern is printed in the first printing region R1. The pattern includes a picture with a pattern, and characters such as chinese characters, hiragana, katakana, letters, numbers, symbols, and pictograms. In the example shown in fig. 5, a plurality of floral patterns are printed. The first printed region R1 does not always have a printed pattern and may be unprinted. The dot area ratio is determined according to the design to be expressed; the design may be printed with only one process color ink or with a combination of multiple process color inks. In the first printing region R1, when the dot area ratio is high (for example, not less than 80% and not more than 100%), the ink penetrates to the back side, and the picture and the character printed on the surface can be easily seen from the back side. Further, when the dot area ratio is low (for example, not less than 0% and not more than 30%), the ink cannot sufficiently penetrate to the back surface, and the back surface is recognized as white or the original color of the fabric in some cases; however, since the print area of the first print region R1 is smaller than that of the second print region R2, even if the rear surface of the first print region R1 is recognized as white, it does not stand out significantly.

The process colors include cyan, magenta, yellow, and black, which are the basic colors of printing. In this embodiment, the total of 12 or more colors are selected from light cyan, light magenta, light black, blue, red, orange, navy, fluorescent magenta, fluorescent yellow, and the like. These colors are selected in this embodiment because the inks of these colors are readily available from commercial suppliers. The colors used as the printing colors are not limited to the above colors, and any colors may be used as long as they are contained in the first negative-pressure ink tank 53.

The second printing region R2 is a region where dots are printed by the second print head 52 using spot color ink introduced from at least one second negative pressure ink tank 54. In the second printing region R2, printing was performed by using a single spot color ink having a dot area per unit area (dot area ratio) of 100%. Fig. 6 shows an example of printing in the second printing region R2. Fig. 6(a) shows a part of the surface of the fabric C. Since the printing was performed at a dot area ratio of 100%, no grainy appearance existed on the surface. Fig. 6(B) shows a portion of the back side of fabric C, to which ink in the surface has penetrated, and the background color is visible. In fig. 6(B), the color is recognized to be slightly lighter than the color of the surface according to the degree of penetration of the ink. The dot area ratio is not limited to 100%, and may be, for example, not less than 80% and not more than 100%, preferably not less than 90% and not more than 100%, as long as there is no granular appearance on the surface of the fabric C and the printed ink in the surface penetrates to the back side so that the characters, drawings, and background printed on the surface are visible from the back side. In the example shown in fig. 5, the second printing region R2 is printed as a background of the design pattern printed in the first printing region R1. The design pattern may also be printed in the second printing region R2.

Spot colors include colors that are not selected as process colors. The "spot color" is the color of an ink obtained by mixing inks of a plurality of process colors or by mixing a diluent with the inks of the process colors. This example uses, as spot color inks, 12 color inks obtained by mixing color inks selected from cyan, magenta, yellow, black, light cyan, light magenta, light black, blue, red, orange, navy color, fluorescent magenta, fluorescent yellow, and the like as process colors. As the spot color, if the hue is the same, a color having higher lightness than the printing color, more specifically, a light color, may be selected. This is because, although the dot area ratio becomes small when printing a light color with the printing color ink, the dot area ratio can be set to 100% by performing printing using the spot color ink, thereby allowing the ink to more easily penetrate to the back surface. Spot colors can be selected to express colors that are difficult to express or tend to result in non-uniformity through process color printing. For example, for spot colors, if the hue is the same, a color with a higher chroma than the process color may be selected. For example, a color having a hue of red, green or blue and a chroma significantly higher than the chroma of the process color may be selected as a spot color because such a color cannot be expressed by the process color printing. Further, for some specific colors, such as brown or dark green, when the printing color printing is performed by reciprocally moving the first printing head 51 in a direction perpendicular to the conveying direction of the web C, the color printed at the time of forward movement and the color printed at the time of backward movement are slightly different, thereby easily causing color unevenness. Therefore, spot colors are selected to express these colors.

According to the above-described embodiment, since printing in the second printing region R2 is performed using a spot color ink obtained by mixing a plurality of printing color inks, the dot area ratio can be increased to be larger than that in the case where a spot color is expressed using a printing color ink. Therefore, the ink in the surface penetrates to the back of the fabric C, allowing characters, drawings, and backgrounds printed on the surface of the fabric C to be seen from the back, and a grainy appearance is not easily seen. Further, since the process color printing is performed in the first printing region R1, various colors and designs can be expressed.

The present invention is not limited to the above-described examples, and various modifications can be made within a scope of keeping the gist of the present invention.

Reference numerals

10 Fabric printing apparatus

20 printing apparatus main body

30 ink supply device

40 ink blending device

41 storage tank

42 mixed ink storage container

50 print head carrying unit

51 first print head

52 second print head

53 first negative pressure ink tank

54 second negative pressure ink tank

C, fabric

R1 first printing area

R2 second printing area