inkjet printer

Abstract

This invention provides an inkjet printer that reduces printing time in multi-layer printing. [Solution] The printer 1 comprises a platen 3 that supports the printing medium, a first white nozzle row 31, a primer nozzle row 32 aligned in the main scanning direction of the first white nozzle row 31, a second white nozzle row 33 positioned offset in the sub-scanning direction of the first white nozzle row 31, a clear nozzle row 34 aligned in the main scanning direction of the second white nozzle row 33, a color nozzle row 35 positioned offset in the sub-scanning direction of the first white nozzle row 31 and the second white nozzle row 33, an ultraviolet irradiation device 15, a carriage 11 on which the first white nozzle row 31, primer nozzle row 32, second white nozzle row 33, clear nozzle row 34, color nozzle row 35, and light irradiation device 15 are mounted, a main scanning motor 61 that moves the carriage 11 in the main scanning direction, and a sub-scanning motor 62 that moves the platen 3 in the sub-scanning direction.

Description

Technical Field

[0001] The present disclosure relates to an inkjet printer.

Background Art

[0002] For example, an inkjet printer described in Patent Document 1 is known. The inkjet printer described in Patent Document 1 includes a first head, a second head, a third head, a fourth head, an ultraviolet irradiation device, a carriage, and a platen. The carriage mounts the first head, the second head, the third head, the fourth head, and the ultraviolet irradiation device. The carriage is movable in the main scanning direction. The platen can support a recording medium. The platen is movable in the sub-scanning direction orthogonal to the main scanning direction.

[0003] The first head has a first nozzle row. The first nozzle row is a row in which a plurality of first nozzles that eject color ink are arranged in the sub-scanning direction. The second head is positioned at an interval from the first head in the main scanning direction. The second head has a second nozzle row. The second nozzle row is a row in which a plurality of second nozzles that eject primer ink are arranged in the sub-scanning direction. The third head is positioned further in the sub-scanning direction than the first head and the second head. The third head has a third nozzle row. The third nozzle row is a row in which a plurality of third nozzles that eject gloss ink are arranged in the sub-scanning direction. The fourth head is positioned at an interval from the third head in the main scanning direction. The fourth head has a fourth nozzle row. The fourth nozzle row is a row in which a plurality of fourth nozzles that eject white ink are arranged in the sub-scanning direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the inkjet printer described above, the first and second heads and the third and fourth heads are arranged in two rows in the sub-scanning direction. Therefore, depending on the printing pattern applied to the printing medium, it is likely that the platen will move to one side in the sub-scanning direction and then to the other side. For example, if a first ink layer made of primer ink is laminated onto the printing medium, and then a white base layer made of white ink is laminated on top of the white base layer, then a second ink layer made of color ink is laminated on top of the white base layer, then when printing such a pattern, it is necessary to move the platen to one side in the sub-scanning direction and then to the other side. As a result, the distance the platen travels from the start to the end of printing becomes longer. Consequently, printing takes longer.

[0006] The purpose of this disclosure is to provide an inkjet printer that shortens printing time in printing that involves stacking multiple layers. [Means for solving the problem]

[0007] (1) This disclosure relates to an inkjet printer. The inkjet printer includes a platen that supports a printing medium, a first nozzle row in which a plurality of first nozzles for ejecting liquid onto the printing medium on the platen are arranged in a sub-scanning direction perpendicular to the main scanning direction, a second nozzle row in which a plurality of second nozzles for ejecting liquid onto the printing medium on the platen are arranged in the sub-scanning direction and are aligned with the first nozzle row in the main scanning direction, a third nozzle row in which a plurality of third nozzles for ejecting liquid onto the printing medium on the platen are arranged in the sub-scanning direction and are offset from the first nozzle row in the sub-scanning direction, a fourth nozzle row in which a plurality of fourth nozzles for ejecting liquid onto the printing medium on the platen are arranged in the sub-scanning direction and are aligned with the third nozzle row in the main scanning direction, and the first nozzle row and the third nozzle row are offset from the sub-scanning direction. The device comprises: a fifth nozzle row in which a plurality of fifth nozzles for discharging liquid onto the printing medium on the platen are arranged in the sub-scanning direction; a light irradiation device positioned offset from the first nozzle row, second nozzle row, third nozzle row, fourth nozzle row, and fifth nozzle row in the main scanning direction, which irradiates light toward the platen; a carriage on which the first nozzle row, second nozzle row, third nozzle row, fourth nozzle row, fifth nozzle row, and light irradiation device are mounted; a first relative movement mechanism for moving one of the carriage and the printing medium on the platen relative to the other in the main scanning direction; and a second relative movement mechanism for moving the other of the carriage and the printing medium on the platen relative to the one in the sub-scanning direction. The first nozzles discharge white ink. The second nozzles discharge a first liquid different from the white ink. The third nozzles discharge the white ink. The fourth nozzle dispenses a second liquid that is different from the white ink and the first liquid. The fifth nozzle dispenses a third liquid that is different from the white ink, the first liquid and the second liquid, and contains a colorant.

[0008] The first, second, third, fourth, and fifth nozzle rows are capable of dispensing liquid over a wide area in the sub-scanning direction on the printing medium while moving in the other direction of the main scanning direction. When the carriage moves in the main scanning direction, light from the light irradiation device is irradiated onto the liquid dispensed from the first or second nozzle row onto the printing medium. Similarly, light from the light irradiation device is irradiated onto the liquid dispensed from the third or fourth nozzle row onto the printing medium. Similarly, light from the light irradiation device is irradiated onto the liquid dispensed from the fifth nozzle row onto the printing medium. Therefore, simply by moving the carriage in the other direction of the main scanning direction, the layer consisting of white ink, the layer consisting of the first liquid, the layer consisting of the second liquid, or the layer consisting of the third liquid can be cured on the printing medium. Furthermore, since the first and second nozzle rows, the third and fourth nozzle rows, and the fifth nozzle row are offset in three rows in the sub-scanning direction, the movement of the platen to the other side in the sub-scanning direction is reduced in printing that involves stacking multiple layers. For example, this is the case when a layer consisting of the first liquid is stacked on the printing medium, a layer consisting of white ink is stacked on top of the layer consisting of the first liquid, and a layer consisting of the third liquid is stacked on top of the layer consisting of the white ink. Another example is when a layer consisting of the first liquid is stacked on the printing medium, a layer consisting of the third liquid is stacked on top of the layer consisting of the first liquid, and a layer consisting of the second liquid is stacked on top of the layer consisting of the third liquid. As a result, compared to a configuration in which the head is arranged in two rows in the sub-scanning direction, the distance the platen moves from the start to the end of printing tends to be shorter in various printing patterns. Consequently, the printing time is reduced. Furthermore, the fifth nozzle row that ejects the third liquid is adjacent to the first or third nozzle row that ejects white ink in the sub-scanning direction. Therefore, in a printing pattern that includes a process of laminating a layer of the third liquid on top of a layer of white ink, or laminating a layer of white ink on top of a layer of the third liquid, the distance the platen travels from the start to the end of printing tends to be shorter. Conversely, if the fifth nozzle row that ejects the third liquid is not adjacent to the first or third nozzle row that ejects white ink in the sub-scanning direction, the platen needs to be moved a large distance in the sub-scanning direction when stacking a layer of the third liquid on top of a layer of white ink, or stacking a layer of white ink on top of a layer of the third liquid. As a result, the distance the platen moves from the start to the end of printing tends to be long. The case in which the fifth nozzle row that ejects the third liquid is not adjacent to the first or third nozzle row that ejects white ink in the sub-scanning direction is, for example, when the second and fourth nozzle rows are located between the first and third nozzle rows and the fifth nozzle row in the sub-scanning direction.

[0009] (2) The third nozzle row and the fourth nozzle row may be located between the first nozzle row and the second nozzle row and the fifth nozzle row in the sub-scanning direction.

[0010] The first and second nozzle rows, the third and fourth nozzle rows, and the fifth nozzle row are arranged sequentially in one direction in the sub-scanning direction. Therefore, for example, when stacking a layer of white ink on top of a layer of first liquid, and then stacking a layer of third liquid on top of the white ink layer, the platen only needs to move in one direction in the sub-scanning direction. In other words, when stacking a layer of white ink on top of a layer of first liquid, and then stacking a layer of third liquid on top of the white ink layer, it is unnecessary to move the platen in the other direction in the sub-scanning direction. As a result, the distance the platen travels from the start to the end of printing is shortened.

[0011] (3) The inkjet printer according to claim 1, wherein the fifth nozzle row is located between the first nozzle row and the second nozzle row and the third nozzle row and the fourth nozzle row in the sub-scanning direction.

[0012] The first and second nozzle rows, the fifth nozzle row, and the third and fourth nozzle rows are arranged sequentially in one direction in the sub-scanning direction. Therefore, for example, when stacking a layer of the third liquid on top of a layer of white ink, and then stacking a layer of the second liquid on top of the third liquid, the platen only needs to move in one direction in the sub-scanning direction. In other words, when stacking a layer of the third liquid on top of a layer of white ink, and then stacking a layer of the second liquid on top of the third liquid, it is unnecessary to move the platen in the other direction in the sub-scanning direction. As a result, the distance the platen travels from the start to the end of printing is shortened.

[0013] (4) The third nozzle row and the fourth nozzle row may be located in one of the sub-scanning directions of the first nozzle row, the second nozzle row, and the fifth nozzle row. The light irradiation device comprises a main irradiation unit and a sub-irradiation unit located in one of the sub-scanning directions from the main irradiation unit, and located in one of the sub-scanning directions from the first end of the third nozzle row in one of the sub-scanning directions and the second end of the fourth nozzle row in one of the sub-scanning directions.

[0014] For example, light can be irradiated from a secondary irradiation unit onto a layer of a second liquid that is laminated on top of a layer of a third liquid. Therefore, compared to the case where light is irradiated from a primary irradiation unit onto the layer of a second liquid that is laminated on top of the layer of a third liquid, the time between the lamination of the second liquid layer on top of the third liquid layer and the irradiation of the second liquid layer with light can be increased. Consequently, the surface irregularities of the second liquid layer are reduced. As a result, the glossiness of the second liquid layer increases. On the other hand, in order to lengthen the time between the layer of the second liquid being laminated on top of the layer of the third liquid and the second liquid being irradiated with light, if the main irradiator attempts to irradiate the second liquid layer laminated on top of the third liquid layer with light, the platen will move to the other side in the sub-scanning direction. As a result, the distance the platen travels from the start to the end of printing becomes longer. In the above configuration, the time between the layer of the second liquid being laminated on top of the layer of the third liquid and the second liquid being irradiated with light can be lengthened simply by moving the platen to one side in the sub-scanning direction. As a result, the distance the platen travels from the start to the end of printing becomes shorter.

[0015] (5) The resolution of the white ink ejected from the first nozzle row and the third nozzle row may be lower than the resolution of the third liquid ejected from the fifth nozzle row.

[0016] For example, when laminating a layer of white ink on top of a layer of a third liquid, the time required to laminate the white ink layer is reduced. The white ink layer is often used, for example, to conceal a layer of color ink. Therefore, the white ink layer does not require the same resolution as the color ink layer. Consequently, when laminating a white ink layer on top of a layer of a third liquid, the printing time can be shortened while maintaining image quality.

[0017] (6) The interval in the main scanning direction between the white ink ejected onto the printing medium from the first nozzle and the third nozzle may be longer than the interval in the main scanning direction between the third liquid ejected onto the printing medium from the fifth nozzle.

[0018] For example, in a case where a layer made of white ink is laminated on a layer made of a third liquid, the time for laminating the layer made of white ink is shortened. The layer made of white ink is often used, for example, for the purpose of hiding a layer made of color ink. For this reason, the layer made of white ink is not required to have the same image quality as the layer made of color ink. As a result, the printing time can be shortened while ensuring the image quality. Effects of the Invention

[0019] According to the present disclosure, printing time is reduced in printing where a plurality of layers are laminated. Brief Description of the Drawings

[0020] [Figure 1] Figure 1 is a schematic view of the internal structure of the printer 1 as viewed obliquely from above. [Figure 2] Figure 2 is a schematic view of the internal structure of the printer 1 as viewed from above. [Figure 3] Figure 3 is a schematic diagram showing a head arrangement pattern. [Figure 4] Figure 4 is a block diagram showing the electrical configuration of the printer 1. [Figure 5] Figure 5 is a flowchart of a printing process. [Figure 6] Figure 6 is a schematic diagram showing a printing pattern. [Figure 7] Figure 7 is a schematic diagram showing a printing pattern. [Figure 8] Figure 8 is a simplified flowchart of the printing process. [Figure 9] Figure 9 is a schematic diagram showing a head arrangement pattern in which the color nozzle row 35 is not adjacent to the first white nozzle row 31 and the second white nozzle row 33 in the front-rear direction. [Figure 10] Figure 10 is a flowchart showing a printing process when printing the printing pattern of Figure 6 using the head arrangement pattern of Figure 9. [Figure 11]Figure 11 is a simplified flowchart of the printing process when printing the print pattern in Figure 7 using the head placement pattern in Figure 9. [Figure 12] Figure 12 is a schematic diagram showing the head arrangement pattern. [Figure 13] Figure 13 is a schematic diagram showing the printing pattern. [Figure 14] Figure 14 is a schematic diagram showing the printing pattern. [Figure 15] Figure 15 is a flowchart showing the printing process when printing the print pattern in Figure 13 using the head placement pattern in Figure 12. [Figure 16] Figure 16 is a flowchart showing the printing process when printing the print pattern in Figure 14 using the head placement pattern in Figure 12. [Figure 17] Figure 17 is a schematic diagram showing the printing pattern. [Figure 18] Figure 18 is a flowchart showing the printing process when printing the print pattern in Figure 17 using the head placement pattern in Figure 12. [Figure 19] Figure 19 is a flowchart showing the printing process when printing the print pattern in Figure 14 using the head placement pattern in Figure 9. [Figure 20] Figure 20 is a flowchart showing the printing process when printing the print pattern in Figure 17 using the head placement pattern in Figure 9. [Figure 21] Figure 21 is a schematic diagram showing a recording unit 4 in which an ultraviolet irradiation device 15 having a secondary irradiation unit 15D is mounted on a carriage 11. [Figure 22] Figure 22 is a flowchart showing the printing process when printing the print pattern in Figure 13 using the head placement pattern in Figure 21. [Modes for carrying out the invention]

[0021] Embodiments of this disclosure will be described below with reference to the drawings as appropriate. It should be noted that the embodiments described below are merely examples of this disclosure, and the embodiments of this disclosure can be modified as appropriate without altering the gist of this disclosure. In the following description, the left-right, front-back, and up-down directions, indicated by arrows in the figures, will be used. The left-right, front-back, and up-down directions are orthogonal to each other.

[0022] Printer 1 performs printing using an inkjet method. Printer 1 ejects liquid onto printing medium A. Examples of printing medium A include fabric, paper, and plastic film. An example of fabric is a T-shirt. Printer 1 is an example of an inkjet printer.

[0023] As shown in Figures 1 and 2, the printer 1 comprises a frame 2, a platen 3, a recording unit 4, and a maintenance mechanism 5. The frame 2 is constructed in a cubic shape by a plurality of front and rear support columns 2A extending in the front-to-back direction, a plurality of left and right support columns 2B extending in the left-to-right direction, and a plurality of up and down support columns 2C extending in the up and down direction. The front end of the frame 2 has an opening 2D. The opening 2D penetrates the center of the frame 2 in the left-to-right direction in the front-to-back direction.

[0024] The platen 3 is positioned to pass through the opening 2D along the front-to-back direction. The platen 3 has a flat plate shape that extends in the front-to-back and left-to-right directions. In plan view, the platen 3 is a rectangle that is long in the front-to-back direction. The platen 3 is supported by a support shaft 6 that extends in the front-to-back direction. The support shaft 6 is fixed to the frame 2 in the opening 2D. The platen 3 is movable in the front-to-back direction along the support shaft 6. The front-to-back direction is an example of a sub-scanning direction.

[0025] The platen 3 is movable in the front-rear direction between the placement position and the printing position. The placement position is the position where the platen 3 protrudes forward from the opening. The placement position is the position where the printing medium A is placed on the platen 3. The placement position is shown by a solid line in Figures 1 and 2. The printing position is where the platen 3 is located behind the placement position. The printing position is the position where liquid is discharged from the recording unit 4 onto the printing medium A placed on the platen 3. The printing position is shown by a dashed line in Figure 2.

[0026] The recording unit 4 includes a carriage 11, a rear head 12, a middle head 13, a front head 14, and an ultraviolet irradiation device 15. The carriage 11 has a flat plate shape that extends in the front-rear and left-right directions. In a plan view, the carriage 11 is a long rectangle in the front-rear direction. The carriage 11 is supported by a front guide rail 16 and a rear guide rail 17.

[0027] The front guide rail 16 and the rear guide rail 17 are fixed to the upper end of the frame 2. The front guide rail 16 is located at the front end of the frame 2. The front guide rail 16 extends horizontally from the left end to the right end of the frame 2. The rear guide rail 17 is located behind the front guide rail 16 at a distance. The rear guide rail 17 is located in the center of the frame 2 in the front-to-back direction. The rear guide rail 17 extends horizontally from the left end to the right end of the frame 2. The carriage 11 is movable horizontally along the front guide rail 16 and the rear guide rail 17.

[0028] The carriage 11 is movable in the left-right direction between the standby position, the maintenance position, and the ejection position. The standby position is located to the right of the center of the frame 2 in the left-right direction. The carriage 11 in the standby position is located at the right end of the carriage 11's range of movement. In Figures 1 and 2, the carriage 11 in the standby position is shown by a solid line. The maintenance position is located to the left of the center of the frame 2 in the left-right direction. The carriage 11 in the maintenance position is located at the left end of the carriage 11's range of movement. The ejection position is located between the standby position and the maintenance position in the left-right direction of the frame 2. The ejection position is the position where, during printing, the three heads eject liquid and the ultraviolet irradiation device 15 irradiates with ultraviolet light. The left-right direction is an example of the main scanning direction.

[0029] As shown in Figures 2 and 3, the rear head 12, middle head 13, and front head 14 are mounted on the carriage 11. The rear head 12, middle head 13, and front head 14 are spaced apart in the front-to-back direction. The rear head 12, middle head 13, and front head 14 are aligned in this order towards the front. The front is one example of the sub-scanning direction. The rear head 12, middle head 13, and front head 14 are located in the same position in the left-to-right direction. The rear head 12, middle head 13, and front head 14 are rectangular when viewed from above. The lower surfaces of the rear head 12, middle head 13, and front head 14 are nozzle surfaces 21 from which multiple nozzles open. The nozzle surfaces 21 are exposed below the carriage 11. The nozzle surfaces 21 are located above the platen 3.

[0030] The rear head 12 has a first white nozzle row 31 and a primer nozzle row 32. The first white nozzle row 31 is located to the left of the center in the left-right direction of the nozzle surface 21. The first white nozzle row 31 is a row of multiple first white nozzles 31A arranged in the front-back direction. In this embodiment, two first white nozzle rows 31 are arranged with a gap between them in the left-right direction. Note that only one first white nozzle row 31 may be arranged. Multiple first white nozzles 31A eject white ink. The first white nozzle row 31 is an example of a first nozzle row. Multiple first white nozzles 31A are an example of multiple first nozzles.

[0031] White ink is used to form a base layer before image formation or to conceal an image. White ink is photocurable. White ink is a photocurable ink that hardens when exposed to light. Examples of light include ultraviolet light. When the white ink hardens, a white layer W is formed.

[0032] The primer nozzle row 32 is located to the right of the center in the left-right direction of the nozzle surface 21. The primer nozzle row 32 is arranged to the right of the first white nozzle row 31. The primer nozzle row 32 is a row in which multiple primer nozzles 32A are arranged in the front-back direction. In this embodiment, two primer nozzle rows 32 are arranged with a gap between them in the left-right direction. Note that only one primer nozzle row 32 may be arranged. Multiple primer nozzles 32A dispense primer ink. The primer nozzle row 32 is an example of a second nozzle row. Multiple primer nozzles 32A is an example of multiple second nozzles.

[0033] Primer ink is an ink used to form a base layer before image formation. Primer ink is tacky and photocurable. Primer ink is a photocurable ink that hardens when exposed to light. Examples of light include ultraviolet light. When the primer ink hardens, a primer layer Pr is formed. Primer ink is an example of a first liquid.

[0034] The central head 13 has a second white nozzle row 33 and a clear nozzle row 34. The second white nozzle row 33 is located to the left of the center in the left-right direction of the nozzle surface 21. The second white nozzle row 33 is a row of multiple second white nozzles 33A arranged in the front-back direction. In this embodiment, two second white nozzle rows 33 are arranged with a gap between them in the left-right direction. Note that only one second white nozzle row 33 may be arranged. Multiple second white nozzles 33A eject white ink. The second white nozzle row 33 is an example of a third nozzle row. Multiple second white nozzles 33A are an example of multiple third nozzles.

[0035] The clear nozzle row 34 is located to the right of the center in the left-right direction of the nozzle surface 21. The clear nozzle row 34 is aligned to the right of the second white nozzle row 33. The clear nozzle row 34 is a row of multiple clear nozzles 34A arranged in the front-to-back direction. In this embodiment, two clear nozzle rows 34 are arranged with a gap between them in the left-to-right direction. Note that only one clear nozzle row 34 may be arranged. Multiple clear nozzles 34A eject clear ink. The clear nozzle row 34 is an example of a fourth nozzle row. Multiple clear nozzles 34A are an example of multiple fourth nozzles.

[0036] Clear ink is an ink used for surface finishing after image formation. Clear ink is photocurable. Clear ink is a photocurable ink that hardens when exposed to light. Examples of light include ultraviolet light. When the clear ink hardens, a clear layer Va is formed. Clear ink is an example of a second liquid.

[0037] The front head 14 has a row of color nozzles 35. The row of color nozzles 35 is a row of multiple color nozzles 35A arranged in the front-to-back direction. The multiple color nozzles 35A eject color ink. Color ink is different from white ink. Hereinafter, color ink will be used as a general term for, for example, black ink, yellow ink, magenta ink, and cyan ink. Color ink is ink used to form an image. The row of color nozzles 35 is an example of a fifth nozzle row. The multiple color nozzles 35A are an example of multiple fifth nozzles.

[0038] In this embodiment, four color nozzle rows 35 are arranged with spacing between them in the left-right direction. Multiple color nozzles 35A in the rightmost color nozzle row 35 eject black ink. Multiple color nozzles 35A in the second color nozzle row 35 from the right eject yellow ink. Multiple color nozzles 35A in the third color nozzle row 35 from the right eject magenta ink. Multiple color nozzles 35A in the leftmost color nozzle row 35 eject cyan ink.

[0039] The color ink is photocurable. The color ink is a photocurable ink that hardens when exposed to light. Examples of light include ultraviolet light. The hardening of the color ink forms the printed layer CL. The color ink is an example of a third liquid.

[0040] The ultraviolet irradiation device 15 is mounted on the carriage 11. The ultraviolet irradiation device 15 is positioned to the right of the rear head 12, the middle head 13, and the front head 14, with a gap between them. Specifically, the ultraviolet irradiation device 15 has a rear irradiation section 15A, a middle irradiation section 15B, and a front irradiation section 15C.

[0041] The rear illumination unit 15A is positioned to the right of the rear head 12, with a gap between them. The rear illumination unit 15A is positioned to coincide with the rear head 12 in the front-to-back direction. The rear illumination unit 15A has a rear light source row 51. The rear light source row 51 is a row of multiple rear light sources 51A arranged in the front-to-back direction. The multiple rear light sources 51A irradiate ultraviolet light onto the white ink ejected from the multiple first white nozzles 31A onto the printing medium A as the carriage 11 moves to the left. The multiple rear light sources 51A irradiate ultraviolet light onto the primer ink ejected from the multiple primer nozzles 32A onto the printing medium A as the carriage 11 moves to the left. Examples of the multiple rear light sources 51A include LEDs.

[0042] The central irradiation unit 15B is positioned at a distance in front of the rear irradiation unit 15A. The central irradiation unit 15B is positioned at a distance to the right of the central head 13. The central irradiation unit 15B is positioned to coincide with the central head 13 in the front-to-back direction. The central irradiation unit 15B has a central light source array 52. ​​The central light source array 52 is a row of multiple central light sources 52A arranged in the front-to-back direction. The multiple central light sources 52A irradiate ultraviolet light onto the white ink ejected onto the printing medium A from multiple second white nozzles 33A as the carriage 11 moves to the left. The multiple central light sources 52A irradiate ultraviolet light onto the clear ink ejected onto the printing medium A from multiple clear nozzles 34A as the carriage 11 moves to the left. Examples of the multiple central light sources 52A include LEDs.

[0043] The front irradiation unit 15C is positioned at a distance forward from the middle irradiation unit 15B. The front irradiation unit 15C is positioned at a distance to the right of the front head 14. The front irradiation unit 15C is positioned to coincide with the front head 14 in the front-rear direction. The front irradiation unit 15C has a front light source row 53. The front light source row 53 is a row of multiple front light sources 53A arranged in the front-rear direction. The multiple front light sources 53A irradiate ultraviolet light onto the color ink ejected from the multiple color nozzles 35A as the carriage 11 moves to the left. Examples of the multiple front light sources 53A include LEDs. The ultraviolet irradiation device 15 is an example of a light irradiation device.

[0044] As shown in Figures 1 and 2, the maintenance mechanism 5 is a mechanism for maintaining the rear head 12, the middle head 13, and the front head 14. The maintenance mechanism 5 is located to the left of the center in the left-right direction of the frame 2. Specifically, the maintenance mechanism 5 has three caps 5A.

[0045] The three caps 5A are positioned spaced apart in the front-to-back direction. The front-to-back positions of the three caps 5A correspond to the front-to-back positions of the rear head 12, middle head 13, and front head 14. The three caps 5A are positioned at coincident locations in the left-to-right direction. The three caps 5A have a rectangular parallelepiped shape that opens upward. The three caps 5A are elastic. The three caps 5A are supported from below by a support plate 41. The support plate 41 has a flat plate shape that extends in the front-to-back and left-to-right directions.

[0046] The support plate 41 is movable vertically between a retracted position and a capping position. The retracted position is the position where the three caps 5A are located below the nozzle surface 21 in the vertical direction. The capping position is the position where the support plate 41 is located above the retracted position. The capping position is the position where the three caps 5A have risen to the point where they are in close contact with the nozzle surfaces 21 of the rear head 12, middle head 13, and front head 14 in the vertical direction. When the carriage 11 is in the maintenance position, the three caps 5A rise to the capping position and come into close contact with the nozzle surface 21.

[0047] The rearmost cap 5A, when in close contact with the nozzle surface 21 of the rear head 12, covers the multiple first white nozzles 31A and multiple primer nozzles 32A from below. The middle cap 5A, when in close contact with the nozzle surface 21 of the middle head 13, covers the multiple second white nozzles 33A and multiple clear nozzles 34A from below. The frontmost cap 5A, when in close contact with the nozzle surface 21 of the front head 14, covers the multiple color nozzles 35A from below. The three caps 5A remain in close contact with the nozzle surfaces 21 of the rear head 12, middle head 13, and front head 14 when printing is not in progress. This suppresses drying on the nozzle surfaces 21 of the rear head 12, middle head 13, and front head 14.

[0048] The maintenance mechanism 5 may further include a wiper for wiping the nozzle surface 21. Furthermore, the maintenance mechanism 5 may further include a flushing box for receiving the liquid discharged from the rear head 12, middle head 13, and front head 14 during flushing.

[0049] As shown in Figure 4, printer 1 includes a controller 130 that controls various operations of printer 1. Controller 130 includes a CPU 131 and an ASIC 135. CPU 131 is connected to memory 140 by an internal bus 137. Memory 140 includes ROM 132, RAM 133, and EEPROM 134. CPU 131, ASIC 135, ROM 132, RAM 133, and EEPROM 134 are connected by an internal bus 137.

[0050] ROM132 stores programs that the CPU131 uses to control various operations. RAM133 is used as a temporary storage area for data and signals used by the CPU131 when executing the above programs, or as a working area for data processing. EEPROM134 stores settings and flags that should be retained even after the power is turned off.

[0051] The ASIC135 is electrically connected to a main scanning motor 61, a sub-scanning motor 62, a head driver 63, an ultraviolet irradiation device 15, a cap motor 64, and an operating unit 65. The main scanning motor 61, sub-scanning motor 62, head driver 63, ultraviolet irradiation device 15, and cap motor 64 are driven by control from the ASIC135.

[0052] The main scanning motor 61 moves the carriage 11 in the left-right direction relative to the printing medium A on the platen 3. The main scanning motor 61 is an example of a first relative movement mechanism. The sub-scanning motor 62 moves the platen 3 in the front-back direction relative to the carriage 11. In other words, the sub-scanning motor 62 moves the printing medium A on the platen 3 in the front-back direction relative to the carriage 11. The sub-scanning motor 62 is an example of a second relative movement mechanism. The head driver 63 is electrically connected to a plurality of piezoelectric elements 66 provided on the rear head 12, the middle head 13, and the front head 14. The head driver 63 can selectively apply voltage to the plurality of piezoelectric elements 66. Among the plurality of piezoelectric elements 66, the piezoelectric element 66 to which voltage is applied discharges liquid from the corresponding nozzle. The ultraviolet irradiation device 15 can selectively irradiate ultraviolet light from the rear irradiation section 15A, the middle irradiation section 15B, and the front irradiation section 15C. The cap motor 64 moves the support plate 41 in the up-down direction. The control unit 65 is a touch panel or the like. The control unit 65 outputs information to the ASIC 135 in response to user operations.

[0053] When ASIC135 ejects white ink from multiple first white nozzles 31A, it moves the carriage 11 to the left faster than when ejecting color ink from multiple color nozzles 35A. As a result, the resolution produced by the white ink is lower than that produced by the color ink. In other words, the lateral spacing of the white ink ejected from the multiple first white nozzles 31A is longer than the lateral spacing of the color ink ejected from the multiple color nozzles 35A.

[0054] When ASIC135 ejects white ink from multiple second white nozzles 33A, it moves the carriage 11 to the left faster than when ejecting color ink from multiple color nozzles 35A. As a result, the resolution produced by the white ink is lower than that produced by the color ink. In other words, the lateral spacing of the white ink ejected from multiple first white nozzles 31A is longer than the lateral spacing of the color ink ejected from multiple color nozzles 35A.

[0055] [Printing Process] Next, the printing process by the controller 130 will be explained with reference to Figure 5. Initially, the platen 3 is in the mounting position. The printing medium A is placed on the platen 3. The carriage 11 is in the standby position. The following describes the case where the printing pattern shown in Figure 6 is laminated. Figure 6 is a printing pattern in which a primer layer Pr, a white layer W, and a printing layer CL are laminated on the printing medium A.

[0056] The controller 130 controls the sub-scanning motor 62 to move the platen 3 backward from the mounting position to the printing position (step S1). The controller 130 controls the main scanning motor 61 to move the carriage 11 to the left from the standby position to the ejection position (step S2). The controller 130 controls the head driver 63 to eject primer ink from multiple primer nozzles 32A at the ejection position (step S3). As a result, primer ink adheres to the printing medium A. At the same time, the controller 130 irradiates ultraviolet light from the back-irradiation section 15A of the ultraviolet irradiation device 15 (step S3). This irradiates the primer ink on the printing medium A with ultraviolet light. As a result, the primer ink hardens and a primer layer Pr is formed on the printing medium A.

[0057] The controller 130 controls the main scanning motor 61 to return the carriage 11 to the standby position (step S4). The controller 130 controls the sub-scanning motor 62 to move the platen 3 forward by one head length (step S5). One head length is the length along the front-to-back direction between the center of one head in the front-to-back direction and the center of the other head in the front-to-back direction between two adjacent heads in the front-to-back direction. The controller 130 controls the main scanning motor 61 to move the carriage 11 to the left from the standby position toward the discharge position (step S6).

[0058] The controller 130 controls the head driver 63 to eject white ink from multiple second white nozzles 33A at the ejection position (step S7). As a result, white ink is ejected onto the primer layer Pr. Simultaneously, the controller 130 irradiates ultraviolet light from the central irradiation section 15B of the ultraviolet irradiation device 15 (step S7). This irradiates the white ink on the primer layer Pr with ultraviolet light. As a result, the white ink hardens, and a white layer W is formed on the primer layer Pr.

[0059] The controller 130 controls the main scanning motor 61 to return the carriage 11 to the standby position (step S8). The controller 130 controls the sub-scanning motor 62 to move the platen 3 forward by one head length (step S9). The controller 130 controls the main scanning motor 61 to move the carriage 11 to the left from the standby position toward the discharge position (step S10).

[0060] The controller 130 controls the head driver 63 to eject color ink from multiple color nozzles 35A at the ejection position (step S11). As a result, color ink is ejected onto the white layer W. Simultaneously, the controller 130 irradiates ultraviolet light from the pre-irradiation section 15C of the ultraviolet irradiation device 15 (step S11). This irradiates the color ink on the white layer W with ultraviolet light. As a result, the color ink hardens, and a printed layer CL is formed on the white layer W.

[0061] The controller 130 controls the main scanning motor 61 to move the carriage 11 to the maintenance position (step S12). The controller 130 controls the capping motor 64 to move the support plate 41 from the retracted position to the capping position (step S13). As a result, the three caps 5A come into close contact with the nozzle surfaces 21 of the rear head 12, middle head 13, and front head 14. The controller 130 controls the sub-scanning motor 62 to move the platen 3 forward from the printing position to the mounting position (step S14). This allows the user to remove the printed material printed on the printing medium A from the platen 3. The controller 130 terminates the printing process.

[0062] In the above embodiment, the first white nozzle row 31, primer nozzle row 32, second white nozzle row 33, clear nozzle row 34, and color nozzle row 35 are capable of dispensing liquid over a wide area in the front-to-back direction on the printing medium A as the carriage 11 moves to the left. When the carriage 11 moves to the left, ultraviolet light is irradiated from the back-irradiation unit 15A onto the liquid dispensed onto the printing medium A from the first white nozzle row 31 or primer nozzle row 32. Similarly, ultraviolet light is irradiated from the middle-irradiation unit 15B onto the liquid dispensed onto the printing medium A from the second white nozzle row 33 or clear nozzle row 34. Similarly, light is irradiated from the front-irradiation unit 15C onto the liquid dispensed onto the printing medium A from the color nozzle row 35. Therefore, simply by moving the carriage 11 to the left, the white layer W, primer layer Pr, clear layer Va, or printing layer CL hardens on the printing medium A.

[0063] In the above embodiment, the first white nozzle row 31 and primer nozzle row 32, the second white nozzle row 33 and clear nozzle row 34, and the color nozzle row 35 are arranged in three rows offset from each other in the front-to-back direction. Therefore, in printing that laminates multiple layers, the movement of the platen 3 backward is reduced. For example, in the printing pattern shown in Figure 6, no movement of the platen 3 backward occurs between the start of printing when the platen 3 moves to the printing position and the end of printing when the platen 3 moves to the mounting position.

[0064] On the other hand, in a head arrangement pattern where the heads are arranged in only two rows in the front-to-back direction, when printing three layers on the printing medium A, the platen 3 is likely to move backward. As a result, the distance the platen 3 travels from the start to the end of printing tends to be long. For example, this is the case when only two heads are arranged, namely the rear head 12 and the middle head 13. The rear head 12 has, for example, a primer nozzle row 32 and a color nozzle row 35. The middle head 13 has, for example, a first white nozzle row 31 and a clear nozzle row 34. In such a head arrangement pattern with only two heads, when printing the printing pattern shown in Figure 6, the platen 3 is moved backward when the printing layer CL is stacked on the white layer W. As a result, compared to a configuration where the heads are arranged in only two rows in the front-to-back direction, the distance the platen 3 travels from the start to the end of printing tends to be shorter in many printing patterns. As a result, the printing time is shortened.

[0065] In the above embodiment, the first white nozzle row 31 and the second white nozzle row 33 are arranged separately on two heads. Therefore, the color nozzle row 35 is adjacent to the first white nozzle row 31 or the second white nozzle row 32 in the front-to-back direction. In the above embodiment, the color nozzle row 35 is adjacent to the second white nozzle row 33 in the front-to-back direction. Therefore, in printing that includes the process of laminating a printing layer CL on a white layer W, or laminating a white layer W on a printing layer CL, the distance that the platen 3 moves tends to be shorter. For example, the printing patterns shown in Figure 6 and Figure 7 can be cited. Figure 7 shows a printing pattern in which a white layer W is laminated on a printing medium A, a printing layer CL is laminated on the white layer W, and a clear layer Va is laminated on the printing layer CL.

[0066] In the printing pattern shown in Figure 6, as shown in Figure 5, the platen 3 only needs to move forward by two head lengths between the time the primer layer Pr is laminated in step S3 and the time the printing layer CL is laminated in step S11. Specifically, the platen 3 moves forward by one head length in step S5 and by another head length in step S9.

[0067] In the printing pattern shown in Figure 7, the platen 3 only needs to move two head lengths in total—one head length forward and one head length backward—between the lamination of the white layer W on the printing medium A and the lamination of the clear layer Va on the printing layer CL. Figure 8 shows the process for laminating the printing pattern shown in Figure 7.

[0068] As shown in Figure 8, first, in step S21, the second row of white nozzles 33 of the middle head 13 deposits a white layer W onto the printing medium A. Next, in step S22, the platen 3 is moved forward by one head length. Then, in step S23, the color nozzle row 35 of the front head 14 deposits a print layer CL onto the white layer W. Then, in step S24, the platen 3 is moved backward by one head length. Then, in step S25, the clear layer Va is deposited onto the print layer CL by the clear nozzle row 34 of the middle head 13.

[0069] Thus, in step S22, the platen 3 moves forward by one head length, and in step S24, it moves backward by one head length. In other words, the platen 3 moves forward by one head length and backward by one head length, for a total of two head lengths.

[0070] On the other hand, Figure 9 shows a head arrangement pattern when the color nozzle row 35 is not adjacent to the second white nozzle row 33 and the first white nozzle row 31 in the front-to-back direction. Specifically, the rear head 12 has the first white nozzle row 31 and the second white nozzle row 33 that eject white ink. The middle head 13 has the primer nozzle row 32 that ejects primer ink and the clear nozzle row 34 that ejects clear ink. The front head 14 has the color nozzle row 35 that ejects color ink.

[0071] In the head arrangement pattern shown in Figure 9, when the printing pattern shown in Figure 6 is laminated, the platen 3 moves 3 head lengths in the front-to-back direction between the time the primer layer Pr is laminated on the printing medium A and the time the printing layer CL is laminated on the white layer W. Thus, in the head arrangement pattern of Figure 9, the distance the platen 3 moves from the start to the end of printing tends to be long.

[0072] Specifically, as shown in Figure 10, first, in step S31, a primer layer Pr is deposited on the printing medium A by the first white nozzle row 31 of the middle head 13. Next, in step S32, the platen 3 is moved backward by one head length. Then, in step S33, a white layer W is deposited on the primer layer Pr by the first white nozzle row 31 of the rear head 12. Then, in step S34, the platen 3 is moved forward by two head lengths. Finally, in step S35, a print layer CL is deposited on the white layer W by the color nozzle row 35 of the front head 14.

[0073] Thus, the platen 3 moves one head length backward in step S32 and two head lengths forward in step S34, for a total of three head lengths.

[0074] In the head arrangement pattern shown in Figure 9, when stacking the print pattern shown in Figure 7, the platen 3 moves 3 head lengths in the front-to-back direction between the time the white layer W is stacked on the printing medium A and the time the clear layer Va is stacked on the print layer CL.

[0075] Specifically, as shown in Figure 11, first, in step S41, a white layer W is deposited on the printing medium A by the first white nozzle row 31 of the rear head 12. Then, in step S42, the platen 3 is moved forward by two head lengths. After that, in step S43, a printing layer CL is deposited on the white layer W by the color nozzle row 35 of the front head 14. Then, in step S44, the platen 3 is moved backward by one head length. After that, in step S45, a clear layer Va is deposited on the printing layer CL by the clear nozzle row 34 of the middle head 13.

[0076] Thus, in the head arrangement pattern of Figure 9, when stacking the printing pattern of Figure 7, the platen 3 moves forward by 2 head lengths in step S42 and backward by 1 head length in step S44, for a total of 3 head lengths. In contrast, in the head arrangement pattern of Figure 3 of the above embodiment, the platen 3 only moves 2 head lengths in the front-rear direction. Therefore, in the above embodiment, the distance the platen 3 moves in the front-rear direction is 1 head length shorter compared to the head arrangement pattern shown in Figure 9.

[0077] In the above embodiment, the first white nozzle row 31 and primer nozzle row 32, the second white nozzle row 33 and clear nozzle row 34, and the color nozzle row 35 are arranged in this order facing forward. Therefore, when stacking the print pattern shown in Figure 6, the platen 3 only needs to move forward towards the placement position from the start to the end of printing. In other words, when stacking the print pattern shown in Figure 6, there is no need to move the platen 3 backward away from the placement position. Therefore, the distance the platen 3 moves from the start to the end of printing is short. The start of printing is when the platen 3 moves to the printing position in step S1. The end of printing is when the platen 3 moves to the placement position in step S14.

[0078] In the above embodiment, when the ASIC 135 ejects white ink from multiple second white nozzles 33A, it moves the carriage 11 to the left faster than when ejecting color ink from multiple color nozzles 35A. As a result, the time required to laminate the white layer W is shortened. In other words, the resolution provided by the white ink is lower than that provided by the color ink. For example, when laminating a white layer W on a printing layer CL, the white layer W may be used to conceal the printing layer CL. Therefore, the white layer W does not require the same resolution as the printing layer CL. Consequently, for example, when laminating a white layer W on a printing layer CL, the printing time can be shortened while ensuring the image quality of the printing layer CL.

[0079] In the above embodiment, when the ASIC 135 ejects white ink from the multiple second white nozzles 33A, it moves the carriage 11 to the left faster than when it ejects color ink from the multiple color nozzles 35A. Therefore, the left-right distance at which the multiple second white nozzles 33A eject white ink onto the printing medium A is longer than the left-right distance at which the multiple color nozzles 35A eject color ink onto the printing medium A. Consequently, for example, when laminating a white layer W on a printing layer CL, the printing time can be shortened while ensuring the image quality of the printing layer CL.

[0080] [Differentiation] In the above embodiment, as shown in Figure 3, the first white nozzle row 31 and primer nozzle row 32, the second white nozzle row 33 and clear nozzle row 34, and the color nozzle row 35 are arranged in this order facing forward. However, the color nozzle row 35 only needs to be adjacent to the first white nozzle row 31 or the second white nozzle row 33 in the front-to-back direction. For example, as shown in Figure 12, the middle head 13 may have a color nozzle row 35. The front head 14 may have a second white nozzle row 33 and a clear nozzle row 34.

[0081] In the head arrangement pattern shown in Figure 12, the color nozzle row 35 is adjacent to the first white nozzle row 31 and the second white nozzle row 33 in the front-to-back direction. Therefore, in many printing patterns, the movement of the platen 3 backward from the start to the end of printing tends to be reduced. In other words, in many printing patterns, the distance the platen 3 moves from the start to the end of printing tends to be short. For example, the printing patterns shown in Figure 13 and Figure 14.

[0082] Figure 13 shows a printing pattern in which a primer layer Pr is laminated on printing medium A, a printing layer CL is laminated on the primer layer Pr, and a clear layer Va is laminated on the printing layer CL. The case in which the printing pattern shown in Figure 13 is laminated in the head arrangement pattern shown in Figure 12 will be explained.

[0083] As shown in Figure 15, first, in step S51, a primer layer Pr is deposited onto the printing medium A by the primer nozzle row 32. Next, in step S52, the platen 3 is moved forward by one head length. Then, in step S53, the print layer CL is deposited on top of the primer layer Pr by the color nozzle row 35 of the middle head 13. Then, in step S54, the platen 3 is moved forward by one head length. Finally, in step S55, the clear layer Va is deposited on top of the print layer CL by the clear nozzle row 34.

[0084] Next, the case in which the print pattern shown in Figure 14 is laminated in the head arrangement pattern shown in Figure 12 will be explained. Figure 14 shows a print pattern in which a primer layer Pr is laminated on the printing medium A, a print layer CL is laminated on the primer layer Pr, and a white layer W is laminated on the print layer CL.

[0085] As shown in Figure 16, first, in step S61, a primer layer Pr is deposited on the printing medium A by the primer nozzle row 32. Next, in step S62, the platen 3 is moved forward by one head length. Then, in step S63, the printing layer CL is deposited on the primer layer Pr by the color nozzle row 35 of the middle head 13. Then, in step S64, the platen 3 is moved forward by one head length. Then, in step S65, the white layer W is deposited on the printing layer CL by the second white nozzle row 33. Finally, in step S66, the platen 3 is moved forward toward the mounting position.

[0086] Thus, in the head arrangement pattern shown in Figure 12, for example, in many printing patterns such as those in Figures 13 and 14, the platen 3 does not move backward from the start to the end of printing.

[0087] In the head arrangement pattern shown in Figure 12, the first white nozzle row 31 and the second white nozzle row 33 are arranged on two separate heads. Therefore, the color nozzle row 35 is adjacent to either the first white nozzle row 31 or the second white nozzle row 32 in the front-to-back direction. In the head arrangement pattern shown in Figure 12, the color nozzle row 35 is adjacent to both the first white nozzle row 31 and the second white nozzle row 33 in the front-to-back direction. In other words, the color nozzle row 35 is located between the first white nozzle row 31 and the second white nozzle row 33 in the front-to-back direction. Therefore, in a printing pattern that includes the process of laminating a printing layer CL on a white layer W or laminating a white layer W on a printing layer CL, the distance the platen 3 moves from the start to the end of printing tends to be shorter compared to the head arrangement pattern in Figure 9. The head arrangement pattern in Figure 9 is the case where the color nozzle row 35 is not adjacent to the first white nozzle row 31 and the second white nozzle row 33 in the front-to-back direction. For example, when the printing patterns shown in Figure 14 and Figure 17 are stacked, the travel distance of the platen 3 tends to be shorter.

[0088] The case in which the print pattern shown in Figure 17 is stacked in the head arrangement pattern shown in Figure 12 will be explained. Note that the case in which the print pattern shown in Figure 14 is stacked in the head arrangement pattern shown in Figure 12 is as described above. Figure 17 shows a print pattern in which a print layer CL is stacked on a printing medium A, a white layer W is stacked on the print layer CL, and a print layer CL is stacked on the white layer W.

[0089] As shown in Figure 18, first, in step S71, the printing layer CL is deposited on the printing medium A by the color nozzle row 35 of the central head 13. Next, in step S72, the platen 3 is moved forward by one head length. Then, in step S73, the white layer W is deposited on the printing layer CL by the second white nozzle row 33. Then, in step S74, the platen 3 is moved backward by one head length. Then, in step S75, the printing layer CL is deposited on the white layer W by the color nozzle row 35 of the central head 13. Finally, in step S76, the platen 3 is moved forward toward the mounting position.

[0090] On the other hand, in the head arrangement pattern shown in Figure 9, for example, when stacking the printing patterns shown in Figures 14 and 17, the travel distance of the platen 3 becomes longer compared to the head arrangement pattern shown in Figure 12. First, the case in which the printing patterns shown in Figure 14 are stacked in the head arrangement pattern shown in Figure 9 will be explained.

[0091] As shown in Figure 19, first, in step S81, the primer layer Pr is deposited onto the printing medium A by the primer nozzle row 32 of the middle head 13. Then, in step S82, the platen 3 is moved forward by one head length. After that, in step S83, the printing layer CL is deposited on top of the primer layer Pr by the color nozzle row 35 of the front head 14. Then, in step S84, the platen 3 is moved backward by two head lengths. After that, in step S85, the white layer W is deposited on top of the printing layer CL by the first white nozzle row 31. Finally, in step S86, the platen 3 is moved forward toward the mounting position.

[0092] Thus, in step S82, the platen 3 moves forward by one head length, in step S84, it moves backward by two head lengths, and in step S86, it moves forward towards the mounting position. Therefore, when stacking the print pattern in Figure 14 with the head arrangement pattern in Figure 9, the distance the platen 3 moves from the start to the end of printing is three head lengths longer compared to when stacking the print pattern in Figure 14 with the head arrangement pattern in Figure 12.

[0093] Next, the case in which the print pattern shown in Figure 17 is stacked in the head arrangement pattern shown in Figure 9 will be explained.

[0094] As shown in Figure 20, first, in step S91, the printing layer CL is laminated onto the printing medium A by the color nozzle row 35 of the front head 14. Then, in step S92, the platen is moved backward by two head lengths. After that, in step S93, the white layer W is laminated on top of the printing layer CL. Then, in step S94, the platen is moved forward by two head lengths. After that, in step S95, the printing layer CL is laminated on top of the white layer W. Finally, in step S96, the platen 3 is moved forward toward the mounting position.

[0095] Thus, in step S92, the platen 3 moves two head lengths backward, in step S94, it moves two head lengths forward, and in step S96, it moves forward towards the mounting position. For this reason, when stacking the print pattern in Figure 17 with the head arrangement pattern in Figure 9, the distance the platen 3 moves from the start to the end of printing is one head length longer compared to when stacking the print pattern in Figure 17 with the head arrangement pattern in Figure 12.

[0096] In the head arrangement pattern shown in Figure 12, the ultraviolet irradiation device 15 may further have a sub-irradiation unit 15D, as shown in Figure 21. The sub-irradiation unit 15D is positioned in front of the front irradiation unit 15C at a distance. The sub-irradiation unit 15D is positioned in front of the front end 33B of the second white nozzle row 33 and the front end 34B of the clear nozzle row 34. The front end 33B is an example of a first end. The front end 34B is an example of a second end. The sub-irradiation unit 15D has a sub-light source row 54. The sub-light source row 54 is a row of multiple sub-light sources 54A arranged in the front-to-back direction. The multiple sub-light sources 54A irradiate ultraviolet light. The rear irradiation unit 15A, the middle irradiation unit 15B, and the front irradiation unit 15C are examples of main irradiation units.

[0097] In the modified example shown in Figure 21, for example, when the printed pattern shown in Figure 13 is laminated, ultraviolet light can be irradiated from the sub-irradiation unit 15D onto the clear layer Va laminated on the printed layer CL.

[0098] Specifically, as shown in Figure 22, in step S55, clear ink is ejected onto the printing layer CL by the clear nozzle row 34. At this time, ultraviolet light is not irradiated from the pre-irradiation unit 15C. Steps S51 to S54 are the same as in Figure 15. Then, in step S56, the platen 3 is moved forward by one head length. After that, in step S57, ultraviolet light is irradiated onto the clear ink from the sub-irradiation unit 15D. As a result, the clear ink hardens and becomes the clear layer Va. In this way, compared to the case where ultraviolet light is irradiated from the pre-irradiation unit 15C onto the clear layer Va laminated on the printing layer CL, the time from when the clear layer Va is laminated on the printing layer CL until the clear layer Va is irradiated with ultraviolet light can be increased. Therefore, compared to the case where the time from when the clear layer Va is laminated on the printing layer CL until the clear layer Va is irradiated with ultraviolet light is short, the droplets of clear ink become smoother, resulting in less unevenness on the clear layer Va. As a result, the glossiness of the clear layer Va is high.

[0099] On the other hand, in order to increase the time between the lamination of the clear layer Va on the printed layer CL and the irradiation of the clear layer Va with ultraviolet light, if ultraviolet light is irradiated onto the clear layer Va from the central irradiation unit 15B, the platen 3 will move backward away from its mounting position. As a result, the distance the platen 3 moves from the start to the end of printing becomes longer.

[0100] In contrast, in the modified example shown in Figure 21, in order to lengthen the time from when the clear layer Va is laminated on the printing layer CL until ultraviolet light is irradiated onto the clear layer Va, in step S56, the platen 3 moves forward by one head length towards the mounting position. In other words, there is no movement of the platen 3 backward away from the mounting position. Therefore, the distance the platen 3 travels from the start to the end of printing is short.

[0101] In the above embodiment, the primer nozzle row 32 dispenses primer ink. However, the primer nozzle row 32 may dispense a liquid different from the white ink.

[0102] In the above embodiment, the clear nozzle row 34 dispenses clear ink. However, the clear nozzle row 34 may dispense a different liquid from the white ink and primer ink.

[0103] In the above embodiment, the color nozzle row 35 dispenses color ink. However, the color nozzle row 35 may dispense a liquid different from the white ink, primer ink, and clear ink, which contains a colorant.

[0104] In the above embodiment, the printing medium A moves in the forward and backward direction as the platen 3 moves in the forward and backward direction. However, the printing medium A may also move in the forward and backward direction on the platen 3, for example, by rollers. In this case, the sub-scanning motor 62 is a motor that drives the rollers.

[0105] In the above embodiment, the carriage 11 moves in the left-right direction relative to the printing medium A on the platen 3. However, the carriage 11 may also move in the front-rear direction relative to the printing medium A on the platen 3. In this case, the sub-scanning motor 62 moves the carriage 11 in the front-rear direction relative to the printing medium A on the platen 3. The main scanning motor 61 moves the printing medium A on the platen 3 in the left-right direction relative to the carriage 11. The rear head 12, middle head 13, and front head 14 are positioned offset from each other in the left-right direction. The ultraviolet irradiation device 15 is positioned offset to one side in the front-rear direction relative to the rear head 12, middle head 13, and front head 14.

[0106] In the above embodiment, the ultraviolet irradiation device 15 is positioned to the right of the rear head 12, middle head 13, and front head 14. However, the ultraviolet irradiation device 15 may be positioned to the left of the rear head 12, middle head 13, and front head 14. In this case, the carriage 11 moves to the right to form the white layer W, primer layer Pr, clear layer Va, or print layer CL.

[0107] In the above embodiment, the ultraviolet irradiation device 15 has a rear irradiation section 15A, a middle irradiation section 15B, and a front irradiation section 15C, which are spaced apart in the front-to-back direction. However, the ultraviolet irradiation device 15 may also be a single unit in which the rear irradiation section 15A, the middle irradiation section 15B, and the front irradiation section 15C are continuous in the front-to-back direction. Furthermore, in the modified example shown in Figure 21, the rear irradiation section 15A, the middle irradiation section 15B, the front irradiation section 15C, and the sub-irradiation section 15D may also be a single unit in which they are continuous in the front-to-back direction.

[0108] In the above embodiment, the rear head 12, middle head 13, and front head 14 are positioned with a gap between them in the front-rear direction. However, the rear head 12, middle head 13, and front head 14 may be a continuous, integrated unit in the front-rear direction. In this case, the first white nozzle row 31 and primer nozzle row 32, the second white nozzle row 33 and clear nozzle row 34, and the color nozzle row 35 may be offset in the front-rear direction. For example, a portion of the first white nozzle row 31 and primer nozzle row 32 may coincide with a portion of the second white nozzle row 33 and clear nozzle row 34 in the front-rear direction. Alternatively, a portion of the second white nozzle row 33 and clear nozzle row 34 may coincide with a portion of the color nozzle row 35 in the front-rear direction.

[0109] In the above embodiment, three heads are arranged in the front-to-back direction. However, four or more heads may be arranged in the front-to-back direction. In this case, for example, a row of special color nozzles, in which multiple special color nozzles for ejecting special color inks are arranged in the front-to-back direction, may be positioned in front of the row of color nozzles 35. The special color ink is a colored ink other than the color ink and white ink.

[0110] In the above embodiment, when the ASIC 135 ejects white ink from the multiple first white nozzles 31A and the multiple second white nozzles 33A, it moves the carriage 11 to the left faster than when it ejects color ink from the multiple color nozzles 35A. In other words, the resolution provided by the white ink is lower than the resolution provided by the color ink.

[0111] However, the resolution achieved by the white ink may be the same as that achieved by the color ink. In this case, for example, the movement speed of the carriage 11 when the white layer W is laminated may be the same as the movement speed of the carriage 11 when the printed layer CL is laminated. Note that the movement speed of the carriage 11 when the white layer W is laminated may be slower than the movement speed of the carriage 11 when the printed layer CL is laminated. As a result, the resolution achieved by the white ink may be higher than that achieved by the color ink.

[0112] In the above embodiment, the spacing of the white ink particles ejected onto the printing medium A in the front-to-back direction is longer than the spacing of the color ink particles ejected onto the printing medium A. However, the spacing of the white ink particles ejected onto the printing medium A in the front-to-back direction may be the same as the spacing of the color ink particles ejected onto the printing medium A. In this case, for example, the movement speed of the carriage 11 when the white layer W is laminated may be the same as the movement speed of the carriage 11 when the printing layer CL is laminated. Note that the movement speed of the carriage 11 when the white layer W is laminated may be slower than the movement speed of the carriage 11 when the printing layer CL is laminated. As a result, the spacing of the white ink particles ejected onto the printing medium A in the front-to-back direction may be shorter than the spacing of the color ink particles ejected onto the printing medium A. [Explanation of symbols]

[0113] 1. Printer (an example of an inkjet printer) 3. Platen 11. Carriage 15. Ultraviolet irradiation device (an example of a light irradiation device) 15D...Sub-irradiation section 31...First white nozzle row (an example of the first nozzle row) 31A...First white nozzle (an example of the first nozzle) 32. Primer nozzle row (an example of the second nozzle row) 32A... Primer nozzle (an example of a second nozzle) 33...Second white nozzle row (an example of the third nozzle row) 33A...Second white nozzle (an example of a third nozzle) 33B...Front end (an example of the first end) 34. Clear nozzle row (an example of the 4th nozzle row) 34A... Clear nozzle (an example of the 4th nozzle) 34B...Front end (an example of the second end) 35. Color nozzle row (an example of the 5th nozzle row) 35A...Color nozzle (an example of the 5th nozzle) A...Print media

Claims

1. A platen that supports the printing medium, A first nozzle row is formed in which a plurality of first nozzles that discharge liquid onto the printing medium on the platen are arranged in a sub-scanning direction perpendicular to the main scanning direction, The above-mentioned first nozzle row is aligned with the above-mentioned main scanning direction, and a second nozzle row is arranged in the above-mentioned sub-scanning direction, wherein a plurality of second nozzles that discharge liquid onto the printing medium on the platen are arranged. A third nozzle row is positioned offset from the first nozzle row in the sub-scanning direction, and consists of a plurality of third nozzles that discharge liquid onto the printing medium on the platen, arranged in the sub-scanning direction. The above-mentioned third nozzle row is aligned with the above-mentioned main scanning direction, and a fourth nozzle row is arranged in the above-mentioned sub-scanning direction, in which a plurality of fourth nozzles that discharge liquid onto the printing medium on the platen are aligned, A fifth nozzle row is positioned offset from the first nozzle row and the third nozzle row in the sub-scanning direction, and consists of a plurality of fifth nozzles that discharge liquid onto the printing medium on the platen, arranged in the sub-scanning direction. A light irradiation device is positioned offset in the main scanning direction of the first, second, third, fourth, and fifth nozzle rows, and irradiates light toward the platen. A carriage on which the above-mentioned first nozzle row, second nozzle row, third nozzle row, fourth nozzle row, fifth nozzle row, and light irradiation device are mounted, A first relative movement mechanism that moves one of the carriage and the printing medium on the platen relative to the other in the main scanning direction, It comprises a second relative movement mechanism that moves the other of the carriage and the printing medium on the platen relative to the other in the sub-scanning direction, The first nozzle described above ejects white ink. The second nozzle described above dispenses a first liquid different from the white ink described above. The above third nozzle ejects the above white ink, The fourth nozzle dispenses a second liquid different from the white ink and the first liquid. The fifth nozzle described above is an inkjet printer that ejects a third liquid which is different from the white ink, the first liquid, and the second liquid, and which contains a colorant.

2. The inkjet printer according to claim 1, wherein the third nozzle row and the fourth nozzle row are located between the first nozzle row and the second nozzle row and the fifth nozzle row in the sub-scanning direction.

3. The inkjet printer according to claim 1, wherein the fifth nozzle row is located between the first nozzle row and the second nozzle row and the third nozzle row and the fourth nozzle row in the sub-scanning direction.

4. The third nozzle row and the fourth nozzle row are located in one of the sub-scanning directions of the first nozzle row, the second nozzle row, and the fifth nozzle row. The above-mentioned light irradiation device is The main irradiation section, The inkjet printer according to claim 3, further comprising: a sub-irradiation unit located in one of the sub-scanning directions from the main irradiation unit, and located in one of the sub-scanning directions from the first end of the third nozzle row in one of the sub-scanning directions and the second end of the fourth nozzle row in one of the sub-scanning directions.

5. The inkjet printer according to claim 1, wherein the resolution of the white ink ejected from the first nozzle row and the third nozzle row is lower than the resolution of the third liquid ejected from the fifth nozzle row.

6. The inkjet printer according to claim 1, wherein the spacing in the main scanning direction of the white ink ejected onto the printing medium from the first nozzle and the third nozzle is longer than the spacing in the main scanning direction of the third liquid ejected onto the printing medium from the fifth nozzle.

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