Printing apparatus

Abstract

To provide a printing apparatus capable of completing the curing of the entire image while suppressing the complexity of controlling the light irradiation section. [Solution] A printing apparatus comprising a sub-scanning movement mechanism that performs a sub-scanning operation to move a mounting table in the sub-scanning direction, a main scanning movement mechanism that performs a main scanning operation to move at least one of a head and a light irradiation unit in the main scanning direction, and a control unit, wherein the control unit controls a normal mode in which a main scanning operation and a sub-scanning operation are alternately performed, in which a main scanning operation is performed in which a first region of the light irradiation unit, which is downstream of the upstream end of the nozzle row in the sub-scanning direction, is lit and irradiated with light, and after the last sub-scanning operation of the normal mode is completed, the sub-scanning movement mechanism is made to perform a pull-back operation to pull the mounting table back to the upstream side in the sub-scanning direction, and the sub-scanning movement mechanism is made to perform a main scanning operation for irradiation in which a region of the light irradiation unit, including a second region upstream of the first region in the sub-scanning direction, is lit and irradiated with light.

Description

Technical Field

[0001] The present invention relates to a printing apparatus.

Background Art

[0002] Patent Document 1 discloses a printing apparatus that alternately performs a pass of irradiating light by lighting an unprinted area irradiation unit on the downstream side in the conveyance direction from the downstream end of a nozzle row while discharging a photocurable ink while moving a head in the scanning direction, and an operation of conveying a long medium such as a roll paper in the conveyance direction. In this printing method, an irradiation shortage area occurs after all dots are formed on the medium. Therefore, it is disclosed that, without conveying the medium, the lighting range is changed upstream by the conveyance length of the medium for one pass from the area lit in the immediately preceding pass, and the irradiation shortage area is irradiated with light.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to Patent Document 1, it is possible to complete the curing of the entire image without excessively conveying the long medium downstream in the conveyance direction. However, if the lighting range is changed every relatively short distance such as the conveyance length of the medium for one pass, the control of the light irradiation unit becomes complicated.

[0005] An object of the present invention is to provide a printing apparatus capable of completing the curing of the entire image while suppressing the complication of the control of the light irradiation unit.

Means for Solving the Problems

[0006] The main invention for achieving the above object is a mounting table for mounting a medium, A head having a nozzle row in which multiple nozzles that eject ink toward the media are arranged in the sub-scanning direction, A light-emitting section that emits light, A sub-scanning movement mechanism that performs a sub-scanning operation to move the aforementioned base from the upstream side to the downstream side in the sub-scanning direction, A main scanning movement mechanism that performs a main scanning operation to move at least one of the head and the light irradiation unit in a main scanning direction intersecting the sub-scanning direction, It comprises a control unit and, The control unit, A normal mode is controlled that alternately performs the main scanning operation, which illuminates the first region of the light irradiation unit downstream of the upstream end of the nozzle row in the sub-scanning direction, and the sub-scanning operation, thereby irradiating light. After the last sub-scan operation in the normal mode has finished, The sub-scanning movement mechanism is made to perform a pull-back operation to pull the aforementioned base back to the upstream side in the sub-scanning direction. The printing apparatus is characterized by performing a main scanning operation for illumination, which involves illuminating the area of ​​the light-irradiating section, including a second area upstream of the first area in the sub-scanning direction, and irradiating it with light. Other features of the present invention will be revealed by the description herein. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a printing apparatus that can complete the curing of the entire image while suppressing the complexity of controlling the light irradiation section. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram of the configuration of the printing device 1. [Figure 2] This is a block diagram of the printing system 80. [Figure 3] This is an explanatory diagram of the arrangement of the head 20 and the light irradiation unit 50. [Figure 4] Figures 4A to 4C are explanatory diagrams of the main scanning operation and the sub-scanning operation. [Figure 5] It is an explanatory diagram of the initial mode in the printing method. [Figure 6] Figures 6A and 6B are explanatory diagrams of the normal mode. [Figure 7] Figure 7A is an explanatory diagram of the normal mode, and Figure 7B is an explanatory diagram when the mounting table 2 is located at the limit position Pd. [Figure 8] It is an explanatory diagram when the mounting table 2 is located at the limit position Pd. [Figure 9] It is an explanatory diagram of the upstream irradiation mode. [Figure 10] It is an explanatory diagram of the upstream irradiation mode. [Figure 11] Figure 11A is a diagram showing the movement range of the head 20 and the light irradiation unit 50 in the main scanning operation, and Figure 11B is a diagram showing the start timing of the retraction operation. [Figure 12] Figures 12A and 12B are explanatory diagrams of a modified example of the upstream irradiation mode. [Figure 13] It is an explanatory diagram about the second method example. [Figure 14] It is an explanatory diagram about the second method example. [Figure 15] Figures 15A and 15B are explanatory diagrams about the third method example. [Figure 16] Figures 16A and 16B are explanatory diagrams of the printing apparatus 100 according to the second embodiment. [Figure 17] Figures 17A and 17B are explanatory diagrams of the printing apparatus 100 according to the second embodiment. [Figure 18] Figures 18A and 18B are explanatory diagrams of the printing apparatus 200 according to the third embodiment. [Figure 19] It is an explanatory diagram of the printing apparatus 200 according to the third embodiment.

Embodiments for Carrying Out the Invention

[0009] ===First Embodiment=== <<Basic Configuration of the Printing System 80>> Figure 1 is an explanatory diagram of the configuration of the printing device 1. Figure 2 is a block diagram of the printing system 80. Figure 3 is an explanatory diagram of the arrangement of the head 20 and the light irradiation unit 50.

[0010] In the following explanation, the direction of movement of the carriage 31 may be referred to as the "main scanning direction." The direction of movement of the media M may be referred to as the "sub-scanning direction" or "carrying direction." The main scanning direction and the sub-scanning direction are intersecting directions (in this case, orthogonal directions).

[0011] The printing system 80 comprises a printing device 1 and a computer 70. The computer 70 is a general-purpose computer on which a device for controlling the printing device 1, such as a print control program, is installed. The computer 70 generates command codes for controlling the printing device 1 and transmits these command codes to the printing device 1. However, the printing system 80 may consist of the printing device alone, as the printing device 1 may perform the functions that the computer 70 would otherwise perform.

[0012] The printing apparatus 1 is a device that ejects ink onto media M. As shown in Figure 2, the printing apparatus 1 includes a mounting table 2 on which the media M is placed, a head 20, a carriage unit 30, a mounting table drive unit 40, a light irradiation unit 50, and a control unit 60. The media M is placed on the mounting table 2. The type of media M is not particularly limited and examples include cut paper, film, cloth, etc.

[0013] As shown in Figure 3, the head 20 has one or more nozzle rows 22 (eight rows in Figure 3) in which multiple nozzles 21 that eject ink toward the media M are arranged in the sub-scanning direction. Note that the drawings in this specification show the nozzle rows 22 as viewed from above the head 20. The head 20 is located on the carriage 31 and is movable in the main scanning direction together with the carriage 31.

[0014] The ink ejected from nozzle 21 is an ink that hardens when exposed to light. Examples of light-curing inks include ultraviolet-curing inks, but inks that harden when exposed to light of other wavelengths may also be used. Examples of inks include color inks (e.g., cyan ink, magenta ink, yellow ink, black ink) and special inks (e.g., clear ink, white ink, silver ink) for printing images on media M. Clear inks include gloss inks for controlling the gloss of the image and primer inks (undercoat adjustment inks) for adjusting the undercoat of media M.

[0015] The carriage unit 30 includes a carriage 31 and a carriage drive motor 32 for moving the carriage 31 in the main scanning direction. The carriage 31 is mounted on a head 20 and a light irradiation unit 50, and the carriage 31 moves in the main scanning direction guided by a guide rail 33.

[0016] The mounting platform drive unit 40 has a mounting platform drive motor 41 and is a unit for moving the mounting platform 2 in the transport direction. The driving force of the mounting platform drive motor 41 is transmitted to the mounting platform 2 via a transmission mechanism (not shown: for example, a feed screw mechanism), and the mounting platform 2 moves in the transport direction.

[0017] The light irradiation unit 50 is a device that irradiates light to cure the photocurable ink that has been ejected from the nozzle 21 and landed on the media M. For example, an LED lamp that emits ultraviolet light can be used. As shown in Figure 3, the light irradiation unit 50 has a length in the transport direction and is positioned further downstream in the transport direction than the nozzle row 22. The light irradiation unit 50 is also divided into three regions 51 to 53 from the upstream side in the transport direction, and these are called the upstream irradiation region 51, the intermediate irradiation region 52, and the downstream irradiation region 53, respectively. The three regions 51 to 53 are configured to be individually controlled to be turned on or off, and the intensity of the light irradiation can be adjusted. Note that the number of regions (regions that can be controlled on or off) that divide the light irradiation unit 50 is not limited to three.

[0018] In Figure 3, the upstream end of the light irradiation unit 50 is shifted downstream from the upstream end of the nozzle row 22, but the upstream end of the light irradiation unit 50 and the upstream end of the nozzle row 22 may coincide. Furthermore, the light irradiation unit 50 is not limited to being provided on only one side of the head 20 in the main scanning direction; it may be provided on both sides of the head 20.

[0019] The control unit 60 of the printing device 1 controls each part of the printing device 1 based on command codes from the computer 70. The control unit 60 includes, for example, an arithmetic processing unit and a memory device (not shown), and the arithmetic processing unit executes a program stored in the memory device.

[0020] <<Main scanning operation and sub-scanning operation>> Figures 4A to 4C are explanatory diagrams of the main scanning operation and the sub-scanning operation. The aforementioned mounting table drive unit 40 (sub-scanning movement mechanism) performs a sub-scanning operation to move the mounting table 2 from the upstream side to the downstream side in the transport direction. The carriage unit 30 (main scanning movement mechanism) performs a main scanning operation to move the head 20 and the light irradiation unit 50 in the main scanning direction. In the following description, the sub-scanning operation will also be called the transport operation, and the main scanning operation will also be called a pass, and the passes may be numbered sequentially (pass 1, pass 2, ...). The control unit 60 of the printing apparatus 1 controls the mounting table drive unit 40 to perform the transport operation and controls the carriage unit 30 to perform passes.

[0021] In this embodiment, we illustrate a case where an image P1 is formed by ink in four passes, and the amount of movement of the mounting platform 2 in one transport operation is 1 / 4 the length of the nozzle row 22 (L1). However, the method of forming the image P1 by ink (number of passes, etc.) is not particularly limited.

[0022] Specifically, as shown in Figure 4A, in the first pass 1, the head 20 moves to one side of the main scanning direction (right side in the drawing) and ejects ink toward the opposing media M. Next, as shown in Figure 4B, during the transport operation, the mounting table 2 moves to the downstream side in the transport direction. Next, as shown in Figure 4C, in pass 2, the head 20 moves to the other side of the main scanning direction (left side in the drawing) and ejects ink toward the opposing media M. In the area where ink was ejected in pass 1, ink is ejected from a nozzle further downstream in pass 2. In this way, the main scanning operation and the transport operation are repeated alternately, so that a predetermined area of ​​the media M (for example, the area where ink was ejected in pass 1) is subjected to ink ejection toward the head 20 over four passes, and a part of the image P1 is formed by the ink. Note that the above is not limited to this; printing may also be performed in which the head 20 ejects ink only when moving to one side of the main scanning direction (unidirectional printing).

[0023] <<Printing method: 1st method example>> Figure 5 is an explanatory diagram of the initial mode in the printing method. The diagram shows the positional relationship between the head 20 and the light irradiation unit 50 and the mounting table 2 in the transport direction in each pass. In the following diagrams, the width of the mounting table 2 may be shown as half.

[0024] The control unit 60 of the printing apparatus 1 controls the initial mode at the start of the printing method. In this embodiment, the ink on the media M is cured using the downstream irradiation area 53 of the light irradiation unit 50, which is downstream of the nozzle row 22 in the transport direction. In the pass immediately after the start of printing, the downstream irradiation area 53 does not face the ink on the media M. Therefore, in the initial mode, the pass is performed with all areas of the light irradiation unit 50, including the downstream irradiation area 53, turned off.

[0025] As the passes (Figures 4A and 4C) and transport operations (Figure 4B) are repeated alternately, an image P1 is formed on the media M using ink. The amount of movement L1 of the mounting platform 2 during the transport operation in the initial mode is constant (here, 1 / 4 the length of the nozzle row 22). As shown in Figure 5, the initial mode is executed up to pass 9, just before the area where ink was ejected in pass 1 faces the downstream irradiation area 53 of the light irradiation unit 50.

[0026] Figures 6A, 6B, and 7A are explanatory diagrams for the normal mode. Figures 7B and 8 are explanatory diagrams for when the mounting table 2 is at the limit position Pd. Figure 8 illustrates the case where the limit position Pd is located downstream of the printing apparatus 1 in this embodiment. The control unit 60 of the printing apparatus 1 performs control for the normal mode after the initial mode. In the normal mode 60, the control unit 60 alternately performs a pass that illuminates the downstream illumination area 53 and irradiates light, and a transport operation. The amount of movement L1 of the mounting table 2 during the transport operation is the same as and constant as in the initial mode.

[0027] In this embodiment, the curing of the ink (photocurable ink) that constitutes image P1 is completed in four passes. Therefore, a predetermined area of ​​the media M (for example, the area where the ink was ejected in pass 1) is irradiated with light facing the downstream irradiation area 53 over four passes, and curing is completed. However, the number of passes in which the ink is irradiated with light in normal mode is not limited to four. Also, the initial mode may be omitted, and the downstream irradiation area 53 may be turned on before the ink on the media M comes into contact with the downstream irradiation area 53.

[0028] In the following explanation, the portion of image P1 that has not yet come into contact with the downstream irradiation area 53 and is not yet irradiated with light (the portion with diagonal lines in the drawing) may be referred to as the "unirradiated area P1," the portion of image P2 that has come into contact with the downstream irradiation area 53 three times or less and is not sufficiently irradiated with light (the portion with halftone dots) may be referred to as the "insufficiently irradiated area P2," and the portion of image P3 that has come into contact with the downstream irradiation area 53 over four passes and is fully cured (the portion that is blacked out) may be referred to as the "cured area P3."

[0029] As shown in Figure 6A, even after the start of normal mode, if the upstream region of the media M faces the head 20 (nozzle row 22) and an image is to be formed, the control unit 60 causes a pass to be performed in which ink is ejected from the nozzles 21 and the downstream illumination area 53 is lit to illuminate the ink on the media M. Such passes are repeated alternately with the transport operation until the pass in which the ejection of ink to the media M is completed (pass 20 in Figure 6B).

[0030] Incidentally, in the printing device 1, the movable range of the mounting table 2 in the transport direction is set according to the size of the housing. In the following explanation, the position of the downstream end of the movable range of the mounting table 2, that is, the position of the downstream end 2D of the mounting table 2 when it is in its furthest downstream position, is sometimes referred to as the "limit position Pd".

[0031] As shown in Figure 7A, the control unit 60 compares the distance L2 in the transport direction from the downstream end 2D of the mounting table 2 to the limit position Pd in ​​the pass 20 in which ink ejection is completed with the amount of movement L1 of the mounting table 2 in the transport operation in normal mode. If the distance L2 is greater than or equal to the amount of movement L1 (L2≧L1), the control unit 60 performs a sub-scan operation even after the pass in which ink ejection is completed, moving the mounting table 2 further downstream. After that, the control unit 60 performs a pass 21 in which the downstream illumination area 53 is lit and light is irradiated without ejecting ink from the nozzle 21.

[0032] Thus, in this first method example, if the mounting table 2 can move in the transport direction even after ink ejection is complete, the normal mode continues, which alternates between a sub-scan operation of a certain amount of movement (L1) and a pass. In other words, the normal mode continues until the mounting table 2 reaches the limit position Pd or a position close to it.

[0033] However, if the housing of the printing device 1 is relatively small and the light irradiation unit 50 is located near the limit position Pd in ​​the transport direction, an unirradiated area P1 will remain on the media M even after the downstream irradiation area 53 has irradiated light in the last pass 21 of the normal mode. Even if an unirradiated area P1 remains, the mounting table 2 cannot move downstream (it cannot move a length greater than the movement amount L1 in the normal mode), and the unirradiated area P1 cannot face the downstream irradiation area 53.

[0034] Specifically, when the configuration of the printing apparatus 1 is as shown in Figure 7B, an un-illuminated area P1 remains. This occurs when, in the transport direction, the upstream end Pp of the printable area on the mounting table 2 (in this case, the media M on the mounting table 2) when the mounting table 2 is at its furthest downstream position (limit position Pd) is located upstream of the upstream end PL of the illumination range of the light irradiation unit 50 in normal mode (in this case, the downstream illumination area 53). In other words, this occurs when the transport distance D1 between the upstream end PL of the illumination range of the light irradiation unit 50 in normal mode and the limit position Pd is shorter than the transport distance D2 between the upstream end Pp of the printable area when the mounting table 2 is at its furthest downstream position and the limit position Pd (D1 <D2)。 Therefore, the control unit 60 switches from the normal mode to the upstream irradiation mode.

[0035] Here, the size of media M matches, but is not limited to, the size of the printable area on the mounting platform 2. The "printable area on the mounting platform 2" is the largest area on the mounting platform 2 that can be covered with ink. If it is possible to cover the entire surface of the mounting platform 2 with ink, the "printable area on the mounting platform 2" is the same as the entire mounting surface of the mounting platform 2. If it is possible to cover an area up to a predetermined distance inward from the edge of the mounting platform 2, the "printable area on the mounting platform 2" is the area up to a predetermined distance inward from the edge of the mounting platform 2. Media M just needs to be placed within the "printable area on the mounting platform 2".

[0036] It should be noted that this embodiment is not limited to cases where the area of ​​the light irradiation unit 50 downstream of the nozzle row 22 is illuminated. For example, there are printing devices configured to perform normal mode by using the upstream half of the nozzle row to eject ink and illuminating the area of ​​the light irradiation unit that overlaps with the downstream half of the nozzle row in the transport direction. In that case, if the mounting table has reached the limit position or a position close to it in a pass where ink ejection using the upstream half of the nozzle row is completed, an unilluminated area will remain.

[0037] Furthermore, in the normal mode described above (Figure 7A), after the ink ejection pass 20 is completed, a transport operation is performed, and a pass 21 is performed in which the downstream illumination area 53 is irradiated with light without ejecting ink, but this is not limited to this. Although not shown, the position of the mounting platform 2 in the ink ejection pass 20 may be at or near the limit position Pd. In that case, the pass in which the downstream illumination area 53 is irradiated with light without ejecting ink is not performed, and the system transitions to the upstream illumination mode.

[0038] Furthermore, even if the above distance D1 is greater than or equal to the distance D2 (D1 ≥ D2), in the following case (see Figure 8), an under-irradiated area P2 will remain even if the normal mode is continued until the mounting platform 2 reaches the limit position Pd. This is when, in the transport direction, the upstream end Pp of the printable range when the mounting platform 2 is at its furthest downstream position is compared with point PL2, which is upstream from the downstream end of the downstream irradiation area 53 by the travel distance L1 of the mounting platform 2 during the transport operation in normal mode, and Pp is located further upstream. In other words, this is when the transport direction distance D3 between point PL2 and the limit position Pd is shorter than the transport direction distance D2 between the upstream end Pp of the printable range when the mounting platform 2 is at its furthest downstream position and the limit position Pd (D3 <D2)。

[0039] Figures 9 and 10 are explanatory diagrams of the upstream irradiation mode. Figure 11A shows the movement range of the head 20 and the light irradiation unit 50 during the main scanning operation, and Figure 11B shows the start timing of the pull-back operation. Figures 12A and 12B are explanatory diagrams of modified examples of the upstream irradiation mode. Figure 12A illustrates the case where the limit position Pd is located downstream of the printing apparatus 1 of this embodiment.

[0040] In the following explanation, we will illustrate the case where, as shown in Figure 9, when the mounting platform 2 reaches the limit position Pd or a position close to it and the normal mode ends, an unirradiated area P1 and an under-irradiated area P2 remain. Also, as shown in Figure 10, the upstream irradiation mode paths after the pull-back operation will be referred to sequentially as path 1a, path 2a, and so on.

[0041] In the upstream irradiation mode, the control unit 60 causes the mounting base drive unit 40 to perform a "pull-back operation" to pull the mounting base 2 back to the upstream side in the transport direction, as shown in Figure 9. Furthermore, the control unit 60 causes the area of ​​the light irradiation unit 50 that includes the area upstream of the downstream irradiation area 53 in the transport direction to be lit and irradiated with light to perform a pass (main scanning operation for irradiation). In the first method example, the intermediate irradiation area 52 and the downstream irradiation area 53 are turned off, and the upstream irradiation area 51 is lit and the pass is performed. Note that if the head 20 and the light irradiation unit 50 can be moved individually in the main scanning direction, in the upstream irradiation mode, the head 20 may not be moved, and only the light irradiation unit 50 may be moved.

[0042] In the pull-back operation, the mounting platform 2 is pulled back to the upstream side in the transport direction until the under-irradiated area P2 faces the upstream irradiation area 51. In the first method example, the mounting platform 2 is pulled back so that the downstream end of the area in the under-irradiated area P2 where curing will be completed in one more pass (the area where curing has been completed in three passes) coincides with the downstream end of the upstream irradiation area 51.

[0043] Furthermore, it is desirable that the control unit 60 perform the pull-back operation such that the time interval from the end of the pass immediately preceding the pull-back operation (the last pass 21 in the normal mode in Figure 9) to the start of the pass immediately following the pull-back operation (pass 1a in Figure 10) is the same as the time interval between passes in the normal mode (the time interval from the end of a certain pass n to the start of the next pass n+1). The time interval between passes in the normal mode is approximately the time required for one transport operation.

[0044] To this end, the control unit 60 starts the pull-back operation at the latest immediately after the light irradiation unit 50 has passed over the mounting table 2 in the pass immediately preceding the pull-back operation (pass 21 in Figure 9). As shown in Figure 11A, in one pass, the light irradiation unit 50 moves from a position Pa located on one side of the mounting table 2 in the main scanning direction to a position Pb located on the other side of the mounting table 2 in the main scanning direction. The pull-back operation may be performed after the light irradiation unit 50 has moved from position Pa to position Pb. However, as shown in Figure 11B, it is preferable to perform the pull-back operation at the timing when the light irradiation unit 50 moves from position Pc on the other end of the mounting table 2 to the other side in the main scanning direction.

[0045] This allows the pull-back operation to begin earlier than the time it takes for the pass to completely finish. Therefore, even if the pull-back operation takes longer than the time it takes for one transport operation in normal mode (even if the amount of pull-back is greater than the amount the mounting platform 2 moves during the transport operation), the time interval between the passes before and after the pull-back operation can be made the same as or close to the time interval between passes in normal mode. As long as the light irradiation unit 50 has passed over the mounting platform 2, the irradiation of the ink on the mounting platform 2 with light has finished, so there is no problem even if the mounting platform 2 is moved before the end of the pass. In addition to adjusting the timing of the pull-back operation, the speed of the pull-back operation may also be adjusted.

[0046] By making the time interval between passes before and after the pull-back operation the same as or close to the time interval between passes in normal mode, the illumination conditions of the area illuminated immediately after the pull-back operation can be made the same as or close to the illumination conditions in normal mode. These illumination conditions include the time interval between light irradiation and the time from when the ink lands on media M until light is irradiated. This makes it possible to make the dot wetting spread more uniform and to make the overall image quality more uniform.

[0047] Subsequently, the control unit 60 alternately performs a pass that illuminates the upstream irradiation area 51 and irradiates it with light, as shown in Figure 10, and a transport operation. The amount of movement of the mounting table 2 during the transport operation in the upstream irradiation mode is the same as the amount of movement L1 of the mounting table 2 during the transport operation in the normal mode, and is constant. As a result, curing is completed for each region corresponding to the length of the mounting table 2's movement L1.

[0048] Furthermore, as shown in Figure 7B, point Pu2, located upstream of the downstream end of the upstream irradiation area 51 by the amount L1 of movement of the mounting platform 2 during the transport operation, coincides with or is located upstream of the upstream end Pp of the printable range when the mounting platform 2 is at the limit position Pd. Therefore, even in the upstream irradiation mode, just like in the normal mode, the curing of the entire image can be completed by alternately repeating the light irradiation path and the transport operation with a movement amount L1. In other words, it is possible to prevent the mounting platform 2 from reaching the limit position Pd or a position close to it during the upstream irradiation mode.

[0049] Furthermore, if the limit position Pd is located further downstream, as in the modified example in Figure 12A, the intermediate irradiation area 52 may be illuminated in the upstream irradiation mode. In this case as well, the point Pu3 located upstream of the downstream end of the intermediate irradiation area 52 by a movement amount L1 should coincide with or be located upstream of the upstream end Pp of the printable range when the mounting table 2 is located at the limit position Pd. By doing so, even in the upstream irradiation mode, the entire image can be cured by alternately repeating the light irradiation path and the transport operation of movement amount L1, just as in the normal mode.

[0050] Furthermore, the light irradiation unit 50 not only controls the on / off state of each divided irradiation area, but also controls the irradiation intensity of each irradiation area (unit: mW / cm²). 2 In some cases, it may be possible to adjust the following. Specifically, the output (irradiation intensity) of the lamp can be adjusted by changing the duty cycle of the PWM control. In that case, the control unit 60 may make the irradiation intensity per unit area of ​​the illumination range of the light irradiation unit 50 (e.g., the opening area where the lamp is exposed on the lower surface of the light irradiation unit 50) the same or different between the normal mode and the upstream irradiation mode.

[0051] For example, the control unit 60 may control the irradiation intensity per unit area of ​​the upstream irradiation region 51 in the upstream irradiation mode to be weaker than the irradiation intensity per unit area of ​​the downstream irradiation region 53 in the normal mode. The applicant's research has shown that if the time interval between the irradiation of light in the previous pass and the irradiation of light in the next pass is long, and the irradiation intensity is increased in the next pass to cure the material, the boundary between the area irradiated by light in the previous pass and the area irradiated by light in the next pass becomes noticeable, and streaks are likely to appear on the image. Therefore, it has been found that by weakening the irradiation intensity in the upstream irradiation mode as described above, the boundary between the area cured in the normal mode and the area cured in the upstream irradiation mode becomes less noticeable. The reason for this is not entirely clear, but one possible reason is that the dots in the area cured in the upstream irradiation mode spread out and blend in with the dots in the area cured in the normal mode, making the boundary less noticeable.

[0052] Furthermore, in the upstream irradiation mode, after a predetermined number of passes have been performed, the control unit 60 returns the irradiation intensity of the upstream irradiation region 51 to the irradiation intensity of the downstream irradiation region 53 in the normal mode. For example, as shown in Figure 10, it is preferable to return the irradiation intensity after irradiation to the under-irradiated region P2 at the end of the normal mode is completed. In Figure 10, the downstream end E1 and upstream end E2 of the under-irradiated region P2 at the end of the normal mode are shown by thick lines. Irradiation of the region that was under-irradiated by 3 passes at the end of the normal mode is completed in pass 3a. In this case, it is preferable to return the irradiation intensity from pass 4a.

[0053] This allows for a weaker irradiation intensity at the boundary between the area irradiated in normal mode and the area irradiated in upstream irradiation mode, making it less likely for streaks to appear on the image. On the other hand, the area upstream of the boundary (the unirradiated area P1 at the end of normal mode) can be cured with the same irradiation intensity as normal mode. Therefore, the overall image quality (how the ink is cured) can be made more uniform, improving print quality.

[0054] In the above case, the under-irradiated area P2 (the area between E1 and E2) at the end of normal mode will be cured in the same 4 passes as in normal mode, but the irradiation intensity after the pull-back operation will be weaker. However, the light from the light irradiation unit 50 irradiates not only the area on the media M facing the illuminated area, but also the surrounding area. Therefore, even after shifting downstream from the position facing the upstream irradiation area 51, light is still emitted, although the amount of light decreases. As a result, the curing of the ink can be completed even in the under-irradiated area P2 at the end of normal mode.

[0055] Furthermore, as shown in the modified example in Figure 12B, in the upstream irradiation mode, the intermediate irradiation area 52 may be illuminated in addition to the upstream irradiation area 51. By doing so, the number of passes (8 passes) in which a predetermined area of ​​the media M faces the illumination range of the light irradiation unit 50 can be increased compared to the number of passes (4 passes) in the normal mode. Therefore, even if the irradiation intensity for the under-irradiated area P2 at the end of the normal mode is weak in some passes, the curing of the ink can be completed more reliably.

[0056] Furthermore, not limited to the above, the irradiation intensity may be weaker than in the normal mode for the entire duration of the upstream irradiation mode. Conversely, the irradiation intensity of the upstream irradiation area 51 in the upstream irradiation mode may be stronger than the irradiation intensity of the downstream irradiation area 53 in the normal mode. In that case, the number of passes that irradiate the upstream edge of the image with light may be reduced (for example, the upstream irradiation mode may be terminated in any of passes 5a to 7a in Figure 10). Even in that case, strong light is irradiated to the upstream edge of the image, so the curing of the ink can be completed while shortening the time of the upstream irradiation mode, thereby shortening the overall printing processing time.

[0057] One of the above irradiation intensity settings in the upstream irradiation mode may be fixedly set in the printing device 1, or the control unit 60 may change the above irradiation intensity setting as appropriate (for example, according to the printing mode). For example, when the high-quality mode is set, the irradiation intensity may be weakened, or when the high-speed printing mode is set, the irradiation intensity may be strengthened.

[0058] <<Printing method: 2nd method example>> Figures 13 and 14 are explanatory diagrams for the second method example. In the second method example, during the pull-back operation, the mounting platform 2 is pulled back further upstream than in the first method example (Figure 9). Specifically, the mounting platform 2 is pulled back so that the downstream end of the region (P2) that was under-irradiated by one pass at the end of the normal mode (before the pull-back operation) coincides with a position shifted downstream by the amount of movement L1 of the transport operation from the upstream side of the upstream irradiation region 51.

[0059] In this case, the region that was under-irradiated by one pass (P2) will be irradiated by four passes in the upstream irradiation mode, receiving three more passes of light than the other regions. Similarly, the region that was under-irradiated by two passes will receive two more passes of light than the other regions, and the region that was under-irradiated by three passes will receive one more pass of light than the other regions. The region that was unirradiated at the end of the normal mode (P1) will be irradiated by the same number of passes (4 passes) as the irradiation pass count in the normal mode.

[0060] In other words, in the second example method, the number of light passes irradiating the region that was an under-irradiated region P2 at the end of the normal mode can be increased. Also, the number of light passes irradiating the region that was an un-irradiated region P1 at the end of the normal mode can be kept the same as in the normal mode.

[0061] Therefore, as shown in Figure 14, even if the irradiation intensity in the upstream irradiation mode is reduced for the area that was under-irradiated P2 at the end of the normal mode, the number of light passes increases, ensuring that the ink is properly cured. In addition, since the irradiation intensity can be reduced at the boundary between the area irradiated in the normal mode and the area irradiated in the upstream irradiation mode, streaks are less likely to appear on the image. On the other hand, by irradiating the area that was un-irradiated P1 at the end of the normal mode with the same irradiation intensity as the normal mode, the overall image quality (how the ink is cured) can be made more uniform, improving print quality. In Figure 14, the irradiation intensity is switched at the timing when the three passes of irradiation are completed for the area that was under-irradiated by three passes. However, the timing of switching the irradiation intensity is not limited to the above; for example, it may be at the timing when irradiation of the area that was un-irradiated P1 begins.

[0062] <<Printing method: 3rd method example>> Figures 15A and 15B are explanatory diagrams of the third method example. In the third method example, the amount of movement of the mounting platform 2 in a single pull-back operation is reduced compared to the first method example. To this end, the control unit 60 lights up the intermediate illumination area 52, which is upstream of the illumination range in normal mode (downstream illumination area 53) and downstream of the uppermost region (upstream illumination area 51) among the multiple (in this case, three) regions into which the light irradiation unit 50 is divided (Figure 15A). Therefore, the control unit 60 performs a pull-back operation so that the downstream end of the region that was an under-illuminated region P2 at the end of normal mode (in pass 21) coincides with the downstream end of the intermediate illumination area 52. The control unit 60 then alternates between a pass that lights up the intermediate illumination area 52 and irradiates light, and a transport operation.

[0063] Subsequently, when the mounting platform 2 reaches the limit position Pd or a position close to it again, if there are still under-irradiated areas P2 or un-irradiated areas P1 remaining, the control unit 60 will perform the pull-back operation again. The control unit 60 will also illuminate the upstream irradiation area 51, which is upstream of the intermediate irradiation area 52 that was illuminated immediately before the second pull-back operation, and turn off the intermediate irradiation area 52. Therefore, the control unit 60 will perform the second pull-back operation so that the downstream end of the area that was under-irradiated area P2 immediately before the second pull-back operation coincides with the downstream end of the upstream irradiation area 51. The control unit 60 will then alternate between illuminating the upstream irradiation area 51 and performing the transport operation. This will complete the curing of the entire image.

[0064] According to the third method example, the amount of movement of the mounting platform 2 in a single pull-back operation can be reduced compared to the first method example. Therefore, the time required for one pull-back operation can be brought closer to the time required for one transport operation, and the time interval between passes before and after the pull-back operation can be brought closer to the time interval between passes in normal mode. Thus, the boundary between the area cured in normal mode and the area cured in upstream irradiation mode can be made less noticeable. However, in the first method example, since there is only one pull-back operation, the number of boundary areas (areas where streaks may occur) between the area cured before the pull-back operation and the area cured after the pull-back operation can be reduced.

[0065] ===Second Embodiment=== Figures 16A, 16B, 17A, and 17B are explanatory diagrams of the printing apparatus 100 of the second embodiment. In the printing apparatus 100 of the second embodiment, during transport operation, the head 120 and the light irradiation unit 150 move from the upstream side to the downstream side in the transport direction, rather than the mounting table 102. The main scanning operation is the same as in the first embodiment, with the head 120 and the light irradiation unit 150 moving in the main scanning direction while ejecting ink and irradiating light. In addition, the light irradiation unit 150 can be controlled to turn on and off for each of the three divided regions in the transport direction (downstream irradiation region 151, intermediate irradiation region 152, and upstream irradiation region 153).

[0066] In the case of the printing apparatus 100 of the second embodiment, the movable range of the head 120 and the light irradiation unit 150 in the transport direction is set according to the size of the housing of the printing apparatus 100. The limit position Pd, which is the position of the downstream end 120D of the movable range of the head 120, is illustrated in Figures 16B and 17A. Therefore, in the normal mode, in which the main scanning operation, which illuminates the area of ​​the light irradiation unit 150 upstream of the downstream end of the nozzle row in the transport direction (in this case, the upstream irradiation area 153), and the transport operation of the head 120 and the light irradiation unit 150 are performed alternately, the same problems as in the first embodiment occur. That is, when the head 120 and the light irradiation unit 150 move to the limit position Pd or a position close to it, an unirradiated area P1 remains as shown in Figure 16B, or an under-irradiated area P2 remains as shown in Figure 17A, because the normal mode cannot be completed.

[0067] Therefore, as shown in Figure 17B, after the final transport operation in normal mode is completed, the control unit 60 performs a "pull-back operation" to pull the head 120 and light irradiation unit 150 back to the upstream side in the transport direction. Note that Figure 17B shows the pull-back operation when the limit position Pd of the head 120 and light irradiation unit 150 is as shown in Figure 16B. In addition, a pass (main scanning operation for irradiation) is performed to illuminate the area of ​​the light irradiation unit 150 that includes the area downstream in the transport direction from the upstream irradiation area 153 (here, the downstream irradiation area 151) and irradiate light. By doing so, the hardening of the entire image can be completed by alternately repeating the pass that illuminates the downstream irradiation area 151 and irradiates light, and the transport operation of the head 120 and light irradiation unit 150.

[0068] ===Third Embodiment=== Figures 18A, 18B, and 19 are explanatory diagrams of the printing apparatus 200 of the third embodiment. In the printing apparatus 200 of the third embodiment, during the transport operation, the media M moves from the upstream side to the downstream side in the transport direction. Figure 18A illustrates a printing apparatus 200 in which a long medium M is transported in the transport direction while being fed out from a roll body by a pair of transport rollers 201, and is supported from below by a platen 202 in the printing area. Note that the media M is not limited to a long shape, but may also be short (cut paper, etc.). The main scanning operation is the same as in the first embodiment, with the head 220 and light irradiation unit 250 moving in the main scanning direction, ejecting ink and irradiating light. In addition, the light irradiation unit 250 can be controlled to turn on and off for each of the three regions divided in the transport direction (upstream irradiation region 251, intermediate irradiation region 252, downstream irradiation region 253).

[0069] In the case of the printing apparatus 200 of the third embodiment, unlike the printing apparatus 1 of the first embodiment, there are no restrictions on the movement of the mounting table, etc., in the transport direction, as the media M is transported. However, as shown in Figure 18B, when the normal mode is performed, in which the main scanning operation, which illuminates the area of ​​the light irradiation unit 250 downstream of the upstream end of the nozzle row 222 in the transport direction (here, the downstream irradiation area 253), and the media M transport operation are performed alternately, the following problems arise. In other words, when the ejection of ink toward the media M (dot formation) is completed, unirradiated areas P1 and under-irradiated areas P2 remain.

[0070] Therefore, after the final transport operation in normal mode is completed (after the dot formation is complete), as shown in Figure 19, the control unit performs a "pull-back operation" to pull the media M back to the upstream side in the transport direction. It also performs a pass (main scanning operation for irradiation) to illuminate the area of ​​the light irradiation unit 250 that includes the area upstream of the downstream irradiation area 253 in the transport direction (in this case, the upstream irradiation area 251) and irradiate it with light. In this way, without transporting the media M further downstream in the transport direction, the curing of the entire image can be completed by alternately repeating the pass that illuminates the upstream irradiation area 251 and irradiates it with light, and the transport operation of the media M.

[0071] ===Summary=== The printing apparatus of the first embodiment comprises a mounting table 2, a head 20, a light irradiation unit 50, a mounting table drive unit 40 (sub-scanning movement mechanism) that performs a sub-scanning operation (transport operation) to move the mounting table 2 from the upstream side to the downstream side in the sub-scanning direction (transport direction), a carriage unit 30 (main scanning movement mechanism) that performs a main scanning operation (pass) to move at least one of the head 20 and the light irradiation unit 50 in the main scanning direction, and a control unit (60). The control unit 60 controls a normal mode in which the main scanning operation, which illuminates a first region of the light irradiation unit 50 (e.g., the downstream irradiation region 53 in Figure 7A) that is downstream of the upstream end of the nozzle row in the sub-scanning direction, and irradiates light, and the sub-scanning operation are performed alternately. Then, after the last sub-scan operation in normal mode is completed, the control unit 60 causes the sub-scanning movement mechanism (e.g., the mounting base drive unit 40) to perform a pull-back operation (e.g., Figure 9) to pull the mounting base 2 back to the upstream side in the sub-scanning direction, and causes the control unit 60 to perform a main scanning operation for illumination (e.g., a pass in upstream illumination mode) to illuminate the area of ​​the light irradiation unit 50 that includes the second area (e.g., the upstream irradiation area 51 in Figure 9) which is upstream of the first area in the sub-scanning direction.

[0072] This allows for the completion of the entire image curing even when there are limitations on the movement of the mounting table 2 in the sub-scanning direction, in printing methods where light irradiation is completed in the main scanning operation after the completion of dot formation. Furthermore, because the mounting table 2 is pulled back to the upstream side, the control of the light irradiation unit 50 does not become complicated (for example, the illumination range of the light irradiation unit 50 does not need to be changed upstream at short distances), and light can be irradiated in the same way as in normal mode. Therefore, the irradiation conditions after the pull-back operation can be made closer to the irradiation conditions of normal mode (irradiation time interval and number of irradiations). In addition, since there is no need to extend the movable range of the mounting table 2 downstream, the printing device 1 can be made smaller.

[0073] The printing apparatus 100 of the second embodiment includes a mounting table 102 on which media M is placed, a head 120 having a nozzle row 122 in which a plurality of nozzles for ejecting ink toward the media M are arranged in the sub-scanning direction (transport direction), a light irradiation unit 150 for irradiating light, a sub-scanning movement mechanism (not shown) that performs a sub-scanning operation (transport operation) to move the head 120 and the light irradiation unit 150 from the upstream side to the downstream side in the transport direction, a main scanning movement mechanism (not shown) that performs a main scanning operation to move at least one of the head 120 and the light irradiation unit 150 in the main scanning direction, and a control unit (not shown). The control unit controls a normal mode in which a main scanning operation and a sub-scanning operation are alternately performed, in which a main scanning operation is performed in which a first region of the light irradiation unit 50 (e.g., the upstream irradiation region 153 in Figure 16B) located upstream of the downstream end of the nozzle row 122 in the sub-scanning direction is lit to irradiate light. Then, after the final sub-scan operation in normal mode is completed, the control unit causes the sub-scanning movement mechanism to perform a pull-back operation to pull the head 120 and the light irradiation unit 150 back to the upstream side in the sub-scanning direction (e.g., Figure 17B), and then performs a main scanning operation for irradiation, which involves lighting up the area of ​​the light irradiation unit 150 that includes the second region downstream of the first region in the sub-scanning direction (e.g., the downstream irradiation region 151 in Figure 17B) and irradiating light.

[0074] This allows for the completion of the entire image curing even when there are limitations on the movement of the head 120 and the light irradiation unit 150 in the sub-scanning direction, in printing methods where light irradiation is completed in the main scanning operation after the completion of dot formation. Furthermore, because the head 120 and the light irradiation unit 150 are pulled back to the upstream side, light can be irradiated in the same way as in normal mode without complicating the control of the light irradiation unit 150 (for example, without changing the illumination range of the light irradiation unit 150 downstream at short distance intervals). Therefore, the irradiation conditions after the pull-back operation can be made closer to the irradiation conditions of normal mode (irradiation time interval and number of irradiations). In addition, since it is not necessary to extend the movable range of the head 120 and the light irradiation unit 150 downstream, the printing device 100 can be made smaller.

[0075] The printing apparatus 200 of the third embodiment includes a head 220 having a nozzle row 222 in which a plurality of nozzles for ejecting ink toward media M are arranged in the sub-scanning direction (transport direction), a light irradiation unit 250 for irradiating light, a sub-scanning movement mechanism (not shown) that performs a sub-scanning operation (transport operation) to move media M from the upstream side to the downstream side in the transport direction, a main scanning movement mechanism (not shown) that performs a main scanning operation to move at least one of the head 220 and the light irradiation unit 250 in the main scanning direction, and a control unit (not shown). The control unit controls a normal mode in which a main scanning operation is performed by illuminating a first region of the light irradiation unit 250 (e.g., the downstream irradiation region 253 in Figure 18B) that is downstream of the upstream end of the nozzle row 222 in the sub-scanning direction, and a sub-scanning operation are performed alternately. Then, after the last sub-scan operation in normal mode is completed, the control unit causes the sub-scanning movement mechanism to perform a pull-back operation to pull the media M back to the upstream side in the sub-scanning direction (e.g., Figure 19), and then performs a main scanning operation for illumination, which involves lighting up the area of ​​the light irradiation unit 250 that includes the second area (e.g., the upstream irradiation area 251 in Figure 19) which is upstream of the first area in the sub-scanning direction, and irradiating it with light.

[0076] This allows for the completion of the entire image curing without transporting the media M further downstream in the transport direction, even when using a printing method where light irradiation is completed during the main scanning operation after dot formation is complete (i.e., even when unirradiated areas P1 or under-irradiated areas P2 remain after all dots to be ejected onto the media M have been ejected, as shown in Figure 18B). Furthermore, because the media M is pulled back to the upstream side, the control of the light irradiation unit 250 does not become complicated (for example, the illumination range of the light irradiation unit 250 does not need to be changed upstream at short distance intervals), and light can be irradiated in the same way as in normal mode. Therefore, the irradiation conditions after the pull-back operation can be made closer to the irradiation conditions of normal mode (irradiation time interval and number of irradiations).

[0077] The order of the pull-back operation and the operation to change the illumination range of the light-emitting units 50, 150, and 250 is not particularly limited. Furthermore, in the printing apparatus 1 of the first embodiment and the printing apparatus 100 of the second embodiment, the normal mode is not limited to continuing until the mounting table 2, or the head 120 and light-emitting unit 150, reach the limit position Pd in ​​the sub-scanning direction or a position close to it. The pull-back operation may be performed earlier (for example, after ejecting all the dots to be ejected onto the media M). Conversely, in the printing apparatus 200 of the third embodiment, even after dot formation, the pull-back operation may be performed after one or more passes in which light is irradiated without ejecting ink from the nozzle.

[0078] The control unit 60 of the first embodiment of the printing apparatus 1 alternately performs a main scanning operation for irradiation (for example, the upstream irradiation mode pass in Figure 10) and a sub-scanning operation (transport operation of the mounting table 2) after the pull-back operation. The control units of the printing apparatus 100 of the second embodiment and the printing apparatus 200 of the third embodiment may be similar.

[0079] This allows transport operations to continue between passes even after the pull-back operation, bringing the time interval between passes closer to that of normal mode. In particular, by making the amount of movement in the transport operation the same in both normal mode and after the pull-back operation, the time interval between passes can be made the same. Therefore, the time interval of light irradiation (how the dots wet) can be made closer in both normal mode and after the pull-back operation, and the overall image quality can be made more uniform.

[0080] In the first embodiment, the control unit 60 performs a pull-back operation (Figure 9) in the sub-scanning direction after the distance L3 from the downstream end 2D of the mounting table 2 to the downstream end Pd of the movable range of the mounting table 2, when a certain sub-scanning operation in normal mode (the transport operation following path 20 in Figure 7A) is completed, becomes less than the movement distance L1 of the mounting table 2 in the sub-scanning operation in normal mode. In the second embodiment, the control unit may also perform a pull-back operation (Figure 17B) in the sub-scanning direction after the distance from the downstream end 120D of the head 120 (or light irradiation unit 150) to the downstream end Pd of the movable range of the head 120 (or light irradiation unit 150) has become less than the travel distance of the head 120 and light irradiation unit 150 during the sub-scanning operation in normal mode.

[0081] As a result, the main scanning operation in normal mode and the sub-scanning operation are performed alternately until the movement of the mounting table 2, head 120, and light irradiation unit 150 in the sub-scanning direction is restricted (until the next sub-scanning operation can no longer be performed). Therefore, the ink can be cured under the same irradiation conditions over a wide area of ​​the image, and the overall quality of the image can be made more uniform.

[0082] In the first embodiment, the control unit 60 reduces the illumination intensity per unit area of ​​the illumination range of the light irradiation unit 150 during the main scanning operation for irradiation (e.g., the upstream irradiation area 51 in Figure 9) to a lower level than the illumination intensity per unit area of ​​the illumination range of the light irradiation unit 150 in normal mode (e.g., the downstream irradiation area 53 in Figure 7A). The control units of the printing apparatus 100 in the second embodiment and the printing apparatus 200 in the third embodiment may be similar.

[0083] This makes the boundary between the image hardened in normal mode and the image hardened after the pull-back operation less noticeable. As a result, streaks are less likely to appear in the image, and print quality is improved.

[0084] In the first embodiment, the control unit 60, after the pull-back operation, alternates between a main scanning operation for irradiation and a sub-scanning operation, and after performing a predetermined number of main scanning operations for irradiation (for example, after 3 passes in Figure 10), returns the irradiation intensity of the illumination range of the light irradiation unit 150 to the irradiation intensity of the normal mode. The control units of the printing apparatus 100 in the second embodiment and the printing apparatus 200 in the third embodiment may be similar.

[0085] This allows the ink in the area upstream of the boundary between the image area cured in normal mode and the image area cured after the pull-back operation to be cured with the same irradiation intensity as in normal mode. Therefore, streaks are less likely to appear on the image, and the overall image quality can be made more uniform.

[0086] In the first embodiment, the control unit 60 causes the sub-scanning movement mechanism to perform the retraction operation such that the time interval between the main scanning operation immediately before the retraction operation (e.g., path 21 in Figure 7A) and the main scanning operation for illumination immediately after the retraction operation (e.g., path 1a in Figure 10) is the same as the time interval of the main scanning operation in normal mode. The control units of the printing apparatus 100 in the second embodiment and the printing apparatus 200 in the third embodiment may be configured similarly.

[0087] This makes the boundary between the image cured in normal mode and the image cured after the pull-back operation less noticeable. In other words, by keeping the time interval the same, the way the dots spread at the boundary can be made closer to how they spread in normal mode. As a result, streaks are less likely to appear in the image, and print quality is improved.

[0088] In the first embodiment, the control unit 60 starts the retraction operation at the latest immediately after the light irradiation unit 50 passes over the mounting table 2 during the main scanning operation immediately preceding the retraction operation (Figure 11B). The same applies to the printing apparatus 100 of the second embodiment. In the third embodiment, the control unit of the printing apparatus 200 should start the retraction operation at the latest immediately after the light irradiation unit passes over the media M.

[0089] This makes it possible to bring the time interval of the main scanning operation immediately before and after the pull-back operation closer to or the same as the time interval of the main scanning operation in normal mode. Furthermore, the pull-back operation may be started not only immediately after the light irradiation unit passes the mounting table 2, but also immediately after the light irradiation units 50, 150, 250 pass over the media M, or immediately after they pass over the area of ​​the media M where the ink has landed. By doing so, the ink on the media M can be cured reliably while the pull-back operation can be started earlier.

[0090] In the first embodiment, the control unit 60 of the printing apparatus 1 turns off the first region (downstream irradiation region 53 in Figure 7A) during the main scanning operation for irradiation. The same applies to the printing apparatus 100 of the second embodiment and the printing apparatus 200 of the third embodiment.

[0091] This suppresses light reflection within the housing of the printing devices 1,100,200, and prevents the hardening of ink adhering to surfaces such as the nozzles of the heads 20,120,220. Furthermore, because a pull-back operation is performed, the first region is more likely to face areas where hardening is complete during the main scanning operation for illumination, and the hardening of the entire image can be completed even if the first region is turned off.

[0092] The first region of the printing apparatus 1 in the first embodiment (downstream irradiation region 53 in Figure 7A) and the first region of the printing apparatus 200 in the third embodiment (downstream irradiation region 253 in Figure 18B) are located downstream of the nozzle rows 22 and 222 in the sub-scanning direction. The first region of the printing apparatus 100 in the second embodiment (upstream irradiation region 153 in Figure 16B) is located upstream of the nozzle row 122 in the sub-scanning direction.

[0093] As a result, in normal mode, the path by which the ink lands on a predetermined area of ​​media M is different from the path by which light is shone on the ink in that predetermined area. Therefore, between the time the ink lands on media M and the time the light is shone, the ink dots can spread out, forming a smooth image. In particular, when forming an image by overlaying a clear ink (gloss ink) image on top of an image made with black and white ink or color ink, the clear ink dots spread out and become smoother, resulting in the formation of a more glossy image.

[0094] In the printing apparatus 1 of the first embodiment, in the sub-scanning direction, the upstream end Pp (Figure 7B) of the printable range when the mounting table 2 is located furthest downstream is located upstream of the upstream end PL of the first region (downstream irradiation region 53). In the second embodiment of the printing apparatus 100, in the sub-scanning direction, the downstream end Ppd (Figure 16B) of the printable range is preferably located downstream of the downstream end PLd of the first region (upstream irradiation region 153) when the head 120 and the light irradiation unit 150 are located at their furthest downstream position (D4 <D3であるとよい)。

[0095] This allows the movable range in the sub-scanning direction of the mounting table 2 in the first embodiment and the head 120 and light irradiation unit 150 in the second embodiment to be kept small, enabling miniaturization of the printing apparatus 1,100. In addition, when the mounting table 2 in the first embodiment and the head 120 and light irradiation unit 150 in the second embodiment reach the downstream limit position Pd or a position close to it, an unirradiated area P1 may remain, but the entire image can be cured by the pull-back operation and the main scanning operation for irradiation. Furthermore, light can be irradiated in the same way as in normal mode even after the pull-back operation.

[0096] In the first embodiment of the printing apparatus 1 (Figure 8), in the sub-scanning direction, the upstream end Pp of the printable range when the mounting table 2 is in its furthest downstream position is located upstream of point PL2, which is an amount of the movement distance (L1) of the mounting table 2 during the sub-scanning operation in normal mode from the downstream end of the first region (downstream irradiation region 53). In the second embodiment of the printing apparatus 100, in the sub-scanning direction, the downstream end Ppd (Figure 17A) of the printable range is preferably located downstream of point PLd2, which is downstream by the travel distance L5 of the head 120 and light irradiation unit 150 during the sub-scanning operation in normal mode from the upstream end of the first region (upstream irradiation region 153) when the head 120 and light irradiation unit 150 are in their furthest downstream position (D4 <D5であるとよい)。

[0097] As a result, the movable range in the sub-scanning direction of the mounting table 2 in the first embodiment and the head 120 and light irradiation unit 150 in the second embodiment can be kept small, allowing the printing apparatus 1,100 to be miniaturized. Furthermore, even if the normal mode is continued until the mounting table 2 in the first embodiment and the head 120 and light irradiation unit 150 in the second embodiment reach the downstream limit position Pd or a position close to it, an under-irradiated area P2 may remain. However, the entire image can be cured by the pull-back operation and the main scanning operation for irradiation. In addition, light can be irradiated in the same way as in the normal mode even after the pull-back operation.

[0098] ===Other Embodiments=== The above embodiments are presented as examples and do not limit the scope of the invention. The above configurations can be combined as appropriate, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The above embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0099] 1 printing device, 2 mounting platforms, 20 heads (heads), 21 nozzles, 22 nozzle rows, 30. Carriage unit (main scanning movement mechanism), 31 carriage, 32 carriage drive motor, 33 Guide rails, 40 Mounting platform drive unit (sub-scanning movement mechanism), 41 Mounting platform drive motor, 50 Light-irradiating section, 51 Upstream irradiation area (second area), 52 intermediate irradiation area, 53 Downstream irradiation area (first area), 60 Control unit, 70 Computers, 80 printing systems, 100 printing equipment, 102 Mounting platform, 120 heads, 122 nozzle rows, 150 Light irradiation section, 151 Downstream irradiation area (second area), 152 intermediate irradiation area, 153 Upstream irradiation area (first area), 200 printing equipment; 201 Conveyor roller, 202 Platen, 220 heads, 222 nozzle rows, 250 light irradiation section, 251 Upstream irradiation area (second area), 252 intermediate irradiation area, 253 Downstream irradiation area (first area),

Claims

1. A mounting platform for placing media, A head having a nozzle row in which multiple nozzles that eject ink toward the media are arranged in the sub-scanning direction, A light-emitting section that emits light, A sub-scanning movement mechanism that performs a sub-scanning operation to move the aforementioned base from the upstream side to the downstream side in the sub-scanning direction, A main scanning movement mechanism that performs a main scanning operation to move at least one of the head and the light irradiation unit in a main scanning direction intersecting the sub-scanning direction, It comprises a control unit and, The control unit, A normal mode is controlled that alternately performs the main scanning operation, which illuminates the first region of the light irradiation unit downstream of the upstream end of the nozzle row in the sub-scanning direction, and the sub-scanning operation, thereby irradiating light. After the last sub-scan operation in the normal mode has finished, The sub-scanning movement mechanism is made to perform a pull-back operation to pull the aforementioned base back to the upstream side in the sub-scanning direction. A printing apparatus characterized by performing a main scanning operation for illumination, which involves illuminating the area of ​​the light-irradiating section, including a second area upstream of the first area in the sub-scanning direction, to emit light.

2. A printing apparatus according to claim 1, The printing apparatus is characterized in that the control unit causes the main scanning operation for irradiation and the sub-scanning operation to be performed alternately after the pull-back operation.

3. A printing apparatus according to claim 1 or 2, The printing apparatus is characterized in that, in the sub-scanning direction, the control unit causes the pull-back operation to be performed after the distance from the downstream end of the aforementioned base to the downstream end of the movable range of the aforementioned base becomes less than the distance the aforementioned base moves during the sub-scanning operation in the normal mode.

4. A printing apparatus according to claim 1 or 2, The printing apparatus is characterized in that the control unit makes the irradiation intensity per unit area of ​​the illumination range of the light irradiation unit weaker than the irradiation intensity per unit area of ​​the illumination range of the light irradiation unit in the normal mode.

5. A printing apparatus according to claim 4, The control unit, After the aforementioned pull-back operation, The main scanning operation for irradiation and the sub-scanning operation are performed alternately. A printing apparatus characterized by performing the main scanning operation for irradiation a predetermined number of times, and then returning the irradiation intensity of the lit area of ​​the light irradiation unit to the irradiation intensity of the normal mode.

6. A printing apparatus according to claim 1 or 2, The printing apparatus is characterized in that the control unit causes the sub-scanning movement mechanism to perform the pull-back operation such that the time interval between the main scanning operation immediately before the pull-back operation and the main scanning operation for irradiation immediately after the pull-back operation is the same as the time interval of the main scanning operation in the normal mode.

7. A printing apparatus according to claim 1 or 2, The printing apparatus is characterized in that the control unit initiates the pull-back operation at the latest immediately after the light irradiation unit passes over the aforementioned base during the main scanning operation immediately preceding the pull-back operation.

8. A printing apparatus according to claim 1 or 2, The printing apparatus is characterized in that the control unit turns off the first region during the main scanning operation for irradiation.

9. A printing apparatus according to claim 1 or 2, A printing apparatus characterized in that the first region is located downstream of the nozzle row in the sub-scanning direction.

10. A printing apparatus according to claim 1 or 2, A printing apparatus characterized in that, in the sub-scanning direction, the upstream end of the printable range when the aforementioned mounting stand is in the most downstream position is located upstream of the upstream end of the first region.

11. A printing apparatus according to claim 1 or 2, A printing apparatus characterized in that, in the sub-scanning direction, the upstream end of the printable range when the aforementioned base is in its most downstream position is located upstream of a point that is an amount upstream from the downstream end of the first region by the distance the aforementioned base moves in the sub-scanning operation in the normal mode.

12. A mounting platform for placing media, A head having a nozzle row in which multiple nozzles that eject ink toward the media are arranged in the sub-scanning direction, A light-emitting section that emits light, A sub-scanning movement mechanism that performs a sub-scanning operation to move the head and the light irradiation unit from the upstream side to the downstream side in the sub-scanning direction, A main scanning movement mechanism that performs a main scanning operation to move at least one of the head and the light irradiation unit in a main scanning direction intersecting the sub-scanning direction, It comprises a control unit and, The control unit, A normal mode is controlled that alternately performs the main scanning operation, which illuminates the first region of the light irradiation unit that is upstream of the downstream end of the nozzle row in the sub-scanning direction, and the sub-scanning operation, thereby irradiating light. After the last sub-scan operation in the normal mode has finished, The sub-scanning movement mechanism is made to perform a pull-back operation to pull the head and the light irradiation unit back to the upstream side in the sub-scanning direction. A printing apparatus characterized by performing a main scanning operation for illumination, which involves illuminating the area of ​​the light-irradiating section, including a second area downstream of the first area in the sub-scanning direction, to emit light.

13. A head having a nozzle row in which multiple nozzles that eject ink toward the media are arranged in the sub-scanning direction, A light-emitting section that emits light, A sub-scanning movement mechanism that performs a sub-scanning operation to move the media from the upstream side to the downstream side in the sub-scanning direction, A main scanning movement mechanism that performs a main scanning operation to move at least one of the head and the light irradiation unit in a main scanning direction intersecting the sub-scanning direction, It comprises a control unit and, The control unit, A normal mode is controlled that alternately performs the main scanning operation, which illuminates the first region of the light irradiation unit downstream of the upstream end of the nozzle row in the sub-scanning direction, and the sub-scanning operation, thereby irradiating light. After the last sub-scan operation in the normal mode has finished, The sub-scanning movement mechanism is made to perform a pull-back operation to pull the media back to the upstream side in the sub-scanning direction. A printing apparatus characterized by performing a main scanning operation for illumination, which involves illuminating the area of ​​the light-irradiating section, including a second area upstream of the first area in the sub-scanning direction, to emit light.

Images