IMAGE RECORDING APPARATUS, IMAGE RECORDING METHOD, AND IMAGE RECORDING PROGRAM

Abstract

To provide an image recording device, image recording method, and image recording program which can suppress ultraviolet-curable ink in a nozzle from being cured during or after irradiation of ultraviolet rays.SOLUTION: An image recording device includes a discharge head which moves in a main scanning direction and discharges ultraviolet-curable ink on a printed medium, a light source which irradiates with ultraviolet rays to cure the ultraviolet-curable ink, a movement mechanism which relatively moves the printed medium in a sub scanning direction orthogonal to the main scanning direction with respect to the discharge head, and a controller. The controller executes stirring processing in which the ink in the discharge head is not discharged but is stirred at least during irradiation of the ultraviolet rays by the light source.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an image recording apparatus such as an inkjet printer, an image recording method using the image recording apparatus, and an image recording program executed by a computer in the image recording apparatus. [Background technology]

[0002] For example, Patent Document 1 discloses a problem in which the ultraviolet-curable ink adhering to the nozzles of a discharge head is irradiated with scattered light from an ultraviolet light source and reflected light from a print medium, causing the ultraviolet-curable ink adhering to the nozzles to harden. In addition, the document discloses that in an image recording device that irradiates ultraviolet light to harden ink, an integrated value obtained by accumulating measured values ​​of the amount of ultraviolet light is compared with a threshold value, and if the integrated value exceeds the threshold value, maintenance work is performed on the discharge head. Examples of the maintenance include blank discharge of ink. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-174900 A Summary of the Invention [Problem to be solved by the invention]

[0004] When performing the blank discharge, it is necessary to move the discharge head to a maintenance position where the blank discharge is performed. However, if the reflected ultraviolet light is irradiated onto the nozzle while the discharge head is moving, there is a problem that the hardening of the ink in the nozzle proceeds. In addition, if it takes a long time to move the discharge head to the maintenance position, the hardening of the ink in the nozzle proceeds easily, and it may become difficult to remove the hardened ink even if the blank discharge is performed for the nozzle.

[0005] Therefore, an object of the present invention is to provide an image recording device, an image recording method, and an image recording program that can prevent ultraviolet-curable ink in a nozzle from curing during or after irradiation with ultraviolet rays. [Means for solving the problem]

[0006] The image recording device of the present invention comprises an ejection head that moves in a main scanning direction and has nozzles that eject ultraviolet-curable ink onto a print medium, a light source that radiates ultraviolet light to harden the ultraviolet-curable ink, a movement mechanism that moves the print medium relative to the ejection head in a sub-scanning direction perpendicular to the main scanning direction, and a controller, wherein the controller executes a stirring process that stirs the ink in the ejection head without ejecting it, at least when ultraviolet light is irradiated by the light source.

[0007] According to the present invention, a stirring process is executed in which the ultraviolet-curable ink in the ejection head is stirred without being ejected at least when the ultraviolet light is irradiated by the light source. As a result, even if the ultraviolet-curable ink in the nozzle is irradiated with scattered light from the ultraviolet light source and reflected light from the print medium, the stirring process can prevent the ink in the nozzle from being hardened during or after irradiation with ultraviolet light. Effect of the Invention

[0008] According to the present invention, it is possible to provide an image recording device, an image recording method, and an image recording program that can prevent ultraviolet-curable ink in a nozzle from curing during or after irradiation with ultraviolet rays. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view showing an image recording apparatus according to an embodiment of the present invention; [Diagram 2] 2 is a plan view showing an ink ejection device provided in the image recording apparatus of FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view showing a configuration of a discharge head. [Figure 4] FIG. 2 is a diagram showing a light-emitting diode chip in an ultraviolet irradiation device. [Diagram 5] FIG. 2 is a block diagram showing components of the image recording device of FIG. 1. [Figure 6] FIG. 1A is a diagram showing that the distance between the platen and the nozzle is a high gap, and FIG. 1B is a diagram showing that the distance is a low gap. [Figure 7] 13A and 13B are diagrams for explaining the ink ejection state when non-ejection flushing is not performed. [Figure 8] 11 is a graph showing a simulation result illustrating a relationship between the distance between the platen and the nozzles and the illuminance of light reflected onto the nozzles. [Figure 9] 4 is a flowchart simply illustrating an image recording method according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An image recording device according to an embodiment of the present invention will be described below with reference to the drawings. The image recording device described below is merely one embodiment of the present invention. Therefore, the present invention is not limited to the following embodiment, and additions, deletions, and modifications are possible without departing from the spirit of the present invention.

[0011] Fig. 1 is a perspective view showing an image recording device 1 according to an embodiment of the present invention. In Fig. 1, directions perpendicular to each other are the up-down direction, the left-right direction, and the front-rear direction. The left-right direction is the main scanning direction Ds, which will be described later, and the front-rear direction is the sub-scanning direction Df, which will be described later. This image recording device 1 not only prints on a print medium W such as printing paper, but also performs goods printing, which prints on a print medium W such as resin, for example, for printing on various goods.

[0012] 1, the image recording device 1 of this embodiment includes a housing 2, operation keys 4, a display unit 5, a platen 6 on which the ejection receiving medium W is placed, and an upper cover 7. The image recording device 1 also includes an ink ejection device 1a (FIG. 2) and a controller 19 (FIG. 5), which will be described later.

[0013] The housing 2 is formed in a box shape. The housing 2 has an opening 2a on the front side and an opening (not shown) on the back side. Operation keys 4 are provided at a position on the front right side of the housing 2. Furthermore, a display unit 5 is provided at a position behind the operation keys 4. The operation keys 4 accept operation inputs by a user. The display unit 5 is formed, for example, of a touch panel, and displays predetermined information. Part of the display unit 5 also functions as an operation key at a predetermined timing. The controller 19 realizes a printing function based on input from the operation keys 4 or external input via a communication interface (not shown), and controls the display of the display unit 5.

[0014] The platen 6 corresponds to a moving mechanism and is configured to be able to place the print medium W on it. The platen 6 has a predetermined thickness and is configured, for example, of a rectangular plate material with the sub-scanning direction Df as the longitudinal direction. The platen 6 is removably supported by a platen support base (not shown). The platen support base is configured to be movable in the sub-scanning direction Df between a printing position where printing is performed on the print medium W and a mounting / detaching position where the print medium W is detached from the platen 6 by driving a transport motor 33 (FIG. 5). As a result, the platen 6 moves the print medium W relative to the discharge head 10 in the sub-scanning direction Df. The printing position is a position where the platen 6 faces the discharge head 10 described below, and the mounting / detaching position is a position where the platen support base is disposed outside the housing 2 and where the print medium W can be placed on the platen 6. During printing, the platen 6 moves in the sub-scanning direction Df, so that the print medium W placed on the platen 6 is transported in the sub-scanning direction Df.

[0015] The upper cover 7 is configured so that it rotates upward when the front part thereof is lifted, thereby exposing the inside of the housing 2.

[0016] 2, the ink ejection device 1a includes a storage tank 62, a carriage 3 on which two ejection heads 10 (10A, 10B) and two ultraviolet ray irradiation devices 40 (40A, 40B) are mounted, and a pair of guide rails 67. As the ejection head 10, for example, an inkjet head that ejects ultraviolet ray curable ink can be used.

[0017] The carriage 3 is supported by a pair of guide rails 67 extending in the main scanning direction Ds, and reciprocates in the main scanning direction Ds along the guide rails 67. This allows the two ejection heads 10 (10A, 10B) and the two ultraviolet irradiation devices 40 (40A, 40B) to reciprocate in the main scanning direction Ds. The ejection heads 10 are connected to a storage tank 62 via a tube 62a.

[0018] In this embodiment, for example, the ejection head 10A ejects ink of each color, yellow (Y), magenta (M), cyan (C), and black (K), which may be collectively referred to as color ink. The above four colors of ink are ejected onto the print medium W, thereby printing a color image on the print medium W. On the other hand, the ejection head 10B ejects white (W) ink and clear (Cr) ink. When printing a color image on the print medium W, for example, fabric, white ink is ejected first as a base ink to reduce the influence on the color and material of the fabric, and color inks are ejected on the white ink. Clear ink is also ejected when providing gloss or protecting the printed portion.

[0019] Ink is stored in the storage tanks 62. A storage tank 62 is provided for each type of ink. For example, six storage tanks 62 are provided, each storing black, yellow, cyan, magenta, white, and clear ink.

[0020] 2, the ink ejection device 1a further includes a purge unit 50 and a wiper unit 54. The purge unit 50 and the wiper unit 54 are disposed on one end side of the pair of guide rails 67 in the main scanning direction Ds so as to overlap with the movement area of ​​the carriage 3.

[0021] The purge unit 50 has a cap 51, a suction pump 52, and a lifting mechanism 53. The suction pump 52 is connected to the cap 51. The lifting mechanism 53 lifts and lowers the cap 51 between a suction position and a standby position. At the standby position, the ejection surface NM (FIG. 3) is separated from the cap 51. On the other hand, at the suction position, the ejection surface NM is covered by the cap 51, forming a sealed space. When the cap 51 is at the suction position, if the suction pump 52 is driven, the sealed space is sucked and ink is discharged from a nozzle hole 121a (FIG. 3) described later. In this manner, a purge process is performed to forcibly discharge ink from the nozzle 121. The purge process may be performed after a stirring process described later.

[0022] The wiping unit 54 has two wipers 55, 56, and a moving mechanism 57. The two wipers 55, 56 are supported by the moving mechanism 57. The moving mechanism 57 moves in the sub-scanning direction Df with the ejection surface NM positioned opposite these wipers 55, 56. As a result, the two wipers 61, 62 perform a wiping operation (i.e., wipe the ejection surface NM) while moving in the sub-scanning direction Df.

[0023] Next, as shown in FIG. 3, the ejection head 10 has a plurality of nozzles 121 that eject droplets using ink from the storage tank 62. The ejection head 10 has a laminate of a flow path forming body and a volume changing section. An ink flow path is formed inside the flow path forming body, and a plurality of nozzle holes 121a are opened in the ejection surface NM, which is the lower surface of the flow path forming body. The volume changing section is driven to change the volume of the ink flow path. At this time, the meniscus vibrates in the nozzle holes 121a and ink is ejected. The configuration of the ejection head 10 will be described in detail below.

[0024] The above-mentioned flow path forming body of the ejection head 10 is a laminate of multiple plates, and the volume changing portion includes a vibration plate 155 and an actuator (piezoelectric element) 160. An insulating film 156 is connected to the top of the vibration plate 155, and a common electrode 161 (described later) is connected to the top of the insulating film 156.

[0025] The multiple plates are stacked including, from bottom to top, a nozzle plate 146, a spacer plate 147, a first flow path plate 148, a second flow path plate 149, a third flow path plate 150, a fourth flow path plate 151, a fifth flow path plate 152, a sixth flow path plate 153, and a seventh flow path plate 154.

[0026] Holes and grooves of various sizes are formed in each plate. Inside the flow path forming body where the plates are stacked, the holes and grooves are combined to form a plurality of nozzles 121, a plurality of individual flow paths 164, and a manifold 122 as ink flow paths.

[0027] The nozzles 121 are formed to penetrate the nozzle plate 146 in the stacking direction. In the ejection surface NM of the nozzle plate 146, a plurality of nozzle holes 121a, which are the tips of the nozzles 121, are aligned in the sub-scanning direction Df to form a nozzle row.

[0028] The manifold 122 supplies ink to the pressure chambers 128 to which an ink ejection pressure is applied. The manifold 122 extends in the sub-scanning direction Df, and is connected to one end of each of the individual flow paths 164. That is, the manifold 122 functions as a common flow path for the ink. The manifold 122 is formed by through-holes that penetrate the first flow path plate 148 to the fourth flow path plate 151 in the stacking direction and recesses that are recessed from the lower surface of the fifth flow path plate 152, which are overlapped in the stacking direction.

[0029] Nozzle plate 146 is disposed below spacer plate 147. Spacer plate 147 is formed of, for example, stainless steel. Spacer plate 147 has recess 145 in which a thin portion constituting damper portion 147a and damper space 147b are formed by being recessed in the thickness direction of spacer plate 147 from the surface on the nozzle plate 146 side by, for example, half etching. With this configuration, damper space 147b is formed as a buffer space between manifold 122 and nozzle plate 146.

[0030] A supply port 122a communicates with the manifold 122. The supply port 122a is formed, for example, in a cylindrical shape and is provided at one end in the sub-scanning direction Df. The manifold 122 and the supply port 122a are connected by a flow path (not shown).

[0031] The multiple individual flow paths 164 are each connected to the manifold 122. The upstream end of each individual flow path 164 is connected to the manifold 122, and the downstream end is connected to the base end of the nozzle 121. Each individual flow path 164 is composed of a first communication hole 125, a supply throttle path 126 which is an individual throttle path, a second communication hole 127, a pressure chamber 128, and a descender 129, and these components are arranged in this order.

[0032] The lower end of the first communication hole 125 is connected to the upper end of the manifold 122, extends upward in the stacking direction from the manifold 122, and penetrates an upper portion of the fifth flow path plate 152 in the stacking direction.

[0033] An upstream end of the supply throttle path 126 is connected to an upper end of the first communication hole 125. The supply throttle path 126 is formed by, for example, half etching, and is configured as a groove recessed from the lower surface of the sixth flow path plate 153. In addition, the upstream end of the second communication hole 127 is connected to the downstream end of the supply throttle path 126, extends upward in the stacking direction from the supply throttle path 126, and is formed so as to penetrate the sixth flow path plate 153 in the stacking direction.

[0034] The upstream end of the pressure chamber 128 is connected to the downstream end of the second communication hole 127. The pressure chamber 128 is formed to penetrate the seventh flow path plate 154 in the stacking direction.

[0035] The descender 129 is formed penetrating the spacer plate 147, the first flow path plate 148, the second flow path plate 149, the third flow path plate 150, the fourth flow path plate 151, the fifth flow path plate 152, and the sixth flow path plate 153 in the stacking direction. The descender 129 has an upstream end connected to the downstream end of the pressure chamber 128 and a downstream end connected to the base end of the nozzle 121. The nozzle 121 overlaps the descender 129 in the stacking direction, for example, and is disposed in the center of the descender 129 in the width direction.

[0036] The vibration plate 155 is laminated on the seventh flow path plate 154 and covers the upper openings of the pressure chambers 128 .

[0037] The actuator 160 includes a common electrode 161, a piezoelectric layer 162, and an individual electrode 163, which are arranged in this order. The common electrode 161 covers the entire surface of the vibration plate 155 via an insulating film 156. The piezoelectric layer 162 is provided for each pressure chamber 128, and is arranged on the common electrode 161 so as to overlap the pressure chamber 128. The individual electrode 163 is provided for each pressure chamber 128, and is arranged on the piezoelectric layer 162. One individual electrode 163, the common electrode 161, and a portion of the piezoelectric layer 162 sandwiched between the two electrodes constitute one actuator 160.

[0038] The individual electrodes 163 are electrically connected to a driver IC. This driver IC receives a control signal from a control unit (not shown) to generate a drive signal (voltage signal) and apply it to the individual electrodes 163. In contrast, the common electrode 161 is always held at ground potential. In this configuration, the active portion of the piezoelectric layer 162 expands and contracts in the planar direction together with the two electrodes 161, 163 in response to the drive signal. In response, the vibration plate 155 deforms in cooperation with the electrode 162, changing in a direction to increase or decrease the volume of the pressure chamber 128. As a result, an ejection pressure that ejects ink from the nozzle 121 is applied to the pressure chamber 128.

[0039] In the ejection head 10 as described above, when ink flows into the manifold 122 via the supply port 122a, it flows from the manifold 122 into the supply throttle passage 126 via the first communication hole 125, and then flows from the supply throttle passage 126 into the pressure chamber 128 via the second communication hole 127. The ink then flows through the descender 129 and into the nozzle 121. When an ejection pressure is applied to the pressure chamber 128 by the actuator 160, the ink is ejected from the nozzle hole 121a.

[0040] Next, Fig. 4 is a diagram showing the light-emitting diode chips DT in the ultraviolet irradiation device. As shown in Fig. 4, the ultraviolet irradiation device 40 has a support substrate 41 and a plurality of light-emitting diode chips DT arranged on the support substrate 41 and emitting ultraviolet light. The ultraviolet irradiation device 40 or the light-emitting diode chips DT corresponds to a light source, and irradiates ultraviolet light for curing the ink discharged by the discharge head 10. The light-emitting diode chips DT are semiconductor elements that generate ultraviolet light. The light-emitting diode chips DT are regularly arranged at predetermined intervals in the main scanning direction Ds and the sub-scanning direction Df, for example. The light-emitting diode chips DT are arranged in a matrix, for example.

[0041] Next, each component of the image recording device 1 of this embodiment will be described with reference to a block diagram. As shown in Fig. 5, the image recording device 1 of this embodiment includes, in addition to the above-mentioned components, a controller 19, a reading device 26, motor driver ICs 30 and 31, head driver ICs 32 and 35, a conveying motor 33, a carriage motor 34, irradiation device driver ICs 36 and 37, a purge driver IC 38, and a wipe driver IC 39.

[0042] The controller 19 has a CPU 20, a storage unit (ROM 21, RAM 22, EEPROM 23, HDD 24), and an ASIC 25. The CPU 20 is a control unit of the image recording device 1, and is connected to the storage unit and controls the driver ICs 30-32, 35-39 and the display unit 5.

[0043] The CPU 20 executes various functions by executing the image recording program of this embodiment stored in the ROM 21. The CPU 20 may be implemented as one processor in the controller 19, or may be implemented as multiple processors that cooperate with each other. The image recording program is read by the reading device 26 from a computer-readable recording medium KB such as a magneto-optical disk or a USB flash memory, and stored in the ROM 21. The ROM 21 also stores a threshold value for the distance h between the platen 6 and the ejection surface NM of the nozzle 121. The RAM 22 stores the calculation results of the CPU 20. The EEPROM 23 stores various initial setting information input by the user. The HDD 24 stores specific information and the like.

[0044] The ASIC 25 is connected to the motor driver ICs 30 and 31, the head driver ICs 32 and 35, the irradiation device driver ICs 36 and 37, the purge driver IC 38, and the wipe driver 39. When the CPU 20 accepts a print job from a user, it outputs an image recording command to the ASIC 25 based on the image recording program. The ASIC 25 drives the driver ICs 30 to 32, 35 to 39 based on the image recording command. The CPU 20 drives the conveyance motor 33 by the motor driver IC 30 to move the platen 6 in the sub-scanning direction Df. The CPU 20 drives the carriage motor 34 by the motor driver IC 31 to move the carriage 3 in the main scanning direction Ds. The CPU 20 ejects ink from the ejection head 10 by the head driver ICs 32 and 35. The CPU 20 ejects ultraviolet light from the light-emitting diode chips DT of the ultraviolet light irradiation devices 40A and 40B by the irradiation device driver ICs 36 and 37. The CPU 20 drives the suction pump 52 and the lifting mechanism 53 of the purge unit 50 via the purge driver IC 38. The CPU 20 drives the moving mechanism 57 of the wiping unit 54 via the wipe driver IC 39.

[0045] FIG. 6 is a diagram for explaining the distance h between the platen 6 and the ejection surface NM of the nozzle 121. As shown in FIG. 6(a), in this embodiment, the distance when the distance h between the platen 6 and the ejection surface NM is the largest is the high gap GH. Also, as shown in FIG. 6(b), the distance when the distance h between the platen 6 and the ejection surface NM is the smallest is the low gap GL. The high gap GH is, for example, 18 mm. The low gap GL is, for example, 2 mm. A print mode in which the distance h is the high gap GH is called a high gap print mode, and a print mode in which the distance h is the low gap GL is called a low gap print mode. A print job includes information instructing the high gap print mode in which printing is performed at the high gap GH and the low gap print mode in which printing is performed at the low gap GL.

[0046] Here, in this embodiment, the controller 19 executes an agitation process (called non-ejection flushing) for agitating the ink in the ejection head 10 without ejecting it at least when the light-emitting diode chip DT is irradiated with ultraviolet light. In detail, the controller 19 agitates the ink in the nozzle 121, the ink in the pressure chamber 128, and the ink in the descender 129 by providing the actuator 160 with a drive signal different from that used when ejecting the ink at least when the light is irradiated with ultraviolet light. In this case, the drive signal is a signal that prevents droplets from being ejected even if the ink meniscus is in a downwardly convex state. The non-ejection flushing in this embodiment will be described in detail below.

[0047] Fig. 7 is a diagram for explaining the ink ejection state when non-ejection flushing is not performed. Using Fig. 7, the ejection state with and without non-ejection flushing according to each illuminance of reflected light to the nozzle 121 will be explained. Note that the reflected light is light emitted from the light-emitting diode chip DT and reflected by at least one of the light-emitting diode chip DT, the platen 6, and the print medium W.

[0048] As shown in FIG. 7, the illuminance of the reflected light to the nozzle 121 is 0 mW / cm 2 and 5mW / cm 2 When the illuminance of the reflected light is 5 mW / cm 2 , the ejection state is good regardless of the presence or absence of non-ejection flushing. 2 When the illuminance of the reflected light to the nozzle 121 is 10 mW / cm or less, it is understood that there is no nozzle 121 that is not ejecting. 2 When non-ejection flushing is performed, a good ejection state can be ensured, but if non-ejection flushing is not performed, there will be areas (areas circled in the figure) that do not achieve a good ejection state (i.e., there will be nozzles 121 that do not eject). From the above, the threshold value of the illuminance of the reflected light is set to 5 mW / cm 2 Let us assume that.

[0049] Next, Fig. 8 is a graph showing the relationship between the distance h between the platen 6 and the ejection surface NM of the nozzle 121 and the illuminance of the reflected light to the nozzle 121. Fig. 8 shows the relationship between the distance h and the illuminance of the reflected light from the platen 6 to the nozzle 121 (hereinafter referred to as platen reflected light), the relationship between the distance h and the illuminance of the reflected light from the print medium W made of ceramic material to the nozzle 121 (hereinafter referred to as ceramic material reflected light), and the relationship between the distance h and the illuminance of the reflected light from the print medium W made of stainless steel material to the nozzle 121 (hereinafter referred to as stainless steel material reflected light).

[0050] In Fig. 8, the threshold of the illuminance of reflected light is set to 5 mW / cm as mentioned above. 2 When the distance h is the minimum value (12 mm) among the light reflected from the platen, the light reflected from the ceramic material, and the light reflected from the stainless steel material, it is the light reflected from the stainless steel material that reaches the threshold value. From this, it is estimated that there is a nozzle 121 that does not eject when the print medium W is made of stainless steel and the distance h is 12 mm or more. In view of this, the controller 19 executes non-ejection flushing as an agitation process when ultraviolet light is irradiated and the distance h is greater than a pre-stored threshold value (10 mm in this embodiment). The above threshold value is stored in the ROM 21.

[0051] Alternatively, instead of or in combination with the above-described judgment of whether or not non-ejection flushing is performed using a threshold value, the following may be performed. That is, the controller 19 performs non-ejection flushing as a stirring process when the printing mode is the high gap printing mode out of the low gap printing mode and the high gap printing mode. The reason why non-ejection flushing is performed in the high gap printing mode in this manner is that the greater the distance h, the greater the spread of the emitted light from the light-emitting diode chip DT, and therefore the greater the illuminance of the reflected light. Note that, when there is a middle gap as one or more distances where the distance h is greater than the low gap GL and smaller than the high gap GH, non-ejection flushing may be performed in the high gap printing mode and the middle gap printing mode.

[0052] Next, the operation of the discharge head 10 and the operation of the light-emitting diode chip DT in this embodiment will be described. In this embodiment, the discharge head 10 performs unidirectional printing, and the light-emitting diode chip DT irradiates ultraviolet light when moving in both directions in the main scanning direction Ds. A detailed description will be given below.

[0053] During one pass in the printing process, the carriage 3 moves to the right in the main scanning direction Ds (FIG. 1). As a result, the ejection head 10 and the ultraviolet ray irradiation device 40 move to the right during the printing process. In this case, the ejection head 10 does not eject ink onto the print medium W while moving to the right in the main scanning direction Ds, and the light-emitting diode chip DT irradiates ultraviolet rays toward the print medium W while moving to the right in the main scanning direction Ds. At this time, the controller 19 executes non-ejection flushing for all the nozzles 121. Note that the reason why the light-emitting diode chip DT irradiates ultraviolet rays in this manner without ejecting ink is to increase the integrated amount of ultraviolet light and sufficiently harden the ink.

[0054] As described above, when one pass of the printing process is completed, the carriage 3 moves leftward in the main scanning direction Ds for the second pass. This causes the ejection head 10 and the ultraviolet ray irradiation device 40 to move leftward in the main scanning direction Ds. In this case, the ejection head 10 ejects ink onto the print medium W while moving leftward in the main scanning direction Ds, and the light-emitting diode chip DT irradiates the ejected ink with ultraviolet rays while moving leftward in the main scanning direction Ds. At this time, the controller 19 executes non-ejection flushing as an agitation process only for the nozzles 121 that do not eject ink.

[0055] As described above, when the light-emitting diode chip DT irradiates ultraviolet light, all the nozzles 121 perform either ink ejection or non-ejection flushing. This causes the ink in the nozzles 121 to be agitated, and the ink is not cured by the ultraviolet light.

[0056] Next, the image recording method in this embodiment will be described using a flowchart. Since the contents are the same as those described above, the description will be simplified in the flowchart. In FIG. 9, when the distance h between the platen 6 and the ejection surface NM of the nozzle 121 is greater than a pre-stored threshold value and when printing is performed in the high gap printing mode, non-ejection flushing is performed as an agitation process (step S1). The non-ejection flushing for each pass is as described above. After the agitation process, the purge process is performed by the purge unit 50 (step S2).

[0057] As described above, according to the image recording device 1 of this embodiment, at least during irradiation of ultraviolet rays by the light-emitting diode chip DT, an agitation process is executed in which the ultraviolet-curable ink in the ejection head 10 is agitated without being ejected. As a result, even if the ultraviolet-curable ink in the nozzle 121 is irradiated with scattered light from the light-emitting diode chip DT and reflected light from the print medium W, the above-mentioned agitation process can prevent the ink in the nozzle 121 from curing during or after irradiation of ultraviolet rays.

[0058] Furthermore, in this embodiment, after non-ejection flushing is performed as an agitation process, a purging process is performed to forcibly discharge ink from the nozzles 121. This makes it possible to discharge the ink before polymerization of the ink in the nozzles 121 progresses.

[0059] In addition, in this embodiment, when ultraviolet light is irradiated and the distance h is greater than a pre-stored threshold value (for example, 10 mm), non-ejection flushing is executed as the stirring process. This makes it possible to avoid unnecessary execution of non-ejection flushing even when the spread of the emitted light from the light-emitting diode chip DT is not so large due to the small distance h.

[0060] In addition, in this embodiment, when the printing mode is the high gap printing mode, non-ejection flushing is executed as the stirring process, which makes it possible to avoid unnecessary execution of non-ejection flushing even when the spread of the emitted light from the light-emitting diode chip DT is not so large due to the small distance h in the low gap printing mode.

[0061] Furthermore, in this embodiment, when the light-emitting diode chip DT irradiates ultraviolet rays, non-ejection flushing is performed as an agitation process for the nozzles 121 that do not eject ink. As a result, even if the nozzles 121 do not eject ink, the ink in the nozzles 121 is agitated and the ink is not cured by ultraviolet rays.

[0062] (Modification) The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention. For example, the following modifications are possible.

[0063] In the above embodiment, a piezoelectric element is used as the actuator 160, but the present invention is not limited to this, and other actuators such as a thermal actuator may be used.

[0064] In the above embodiment, the print medium W is moved relative to the ejection head 10 in the sub-scanning direction Df by conveying the print medium W in the sub-scanning direction Df by the platen 6, but the present invention is not limited to this. It is also possible to realize a configuration in which the print medium W is moved relative to the ejection head 10 in the sub-scanning direction Df by moving the ejection head 10 in the sub-scanning direction Df relative to the print medium W.

[0065] In the above embodiment, the high gap GH is 18 mm and the low gap GL is 2 mm, but the high gap GH and the low gap GL are not limited to the above values, and the low gap GL may be smaller than the high gap GH. For example, the high gap GH is 7 mm or more, and the difference between the high gap GH and the low gap GL is 5 mm or more.

[0066] Furthermore, in the above embodiment, the carriage 3 is equipped with two ejection heads 10 (10A, 10B) and two ultraviolet irradiation devices 40 (40A, 40B), but this is not limited thereto, and only one ejection head 10 and one ultraviolet irradiation device 40 may be equipped thereon. [Explanation of symbols]

[0067] 1 Image recording device 3 Carriage 6 Platen 10, 10A, 10B Discharge head 19 Controller 40,40A,40B UV irradiation equipment 121 Nozzle Df Sub-scanning direction Ds Main scanning direction DT Light Emitting Diode Chip W Printing medium

Claims

1. An ejection head that moves in a main scanning direction and has nozzles that eject ultraviolet-curable ink onto a print medium; a light source that irradiates ultraviolet light to cure the ultraviolet-curable ink; a movement mechanism that moves the print medium relative to the ejection head in a sub-scanning direction perpendicular to the main scanning direction; A controller, the moving mechanism includes a platen on which the printing medium is placed, the controller executes an agitation process for agitating the ink in the ejection head without ejecting the ink at least when the ink is irradiated with ultraviolet light by the light source; The controller executes the stirring process when the ultraviolet light is irradiated and the distance between the platen and the nozzle is greater than a pre-stored threshold value.

2. An ejection head that moves in a main scanning direction and has nozzles that eject ultraviolet-curable ink onto a print medium; a light source that irradiates ultraviolet light to cure the ultraviolet-curable ink; a movement mechanism that moves the print medium relative to the ejection head in a sub-scanning direction perpendicular to the main scanning direction; A controller, the moving mechanism includes a platen on which the printing medium is placed, the controller executes an agitation process for agitating the ink in the ejection head without ejecting the ink at least when the ink is irradiated with ultraviolet light by the light source; The controller performs the stirring process when the printing mode is a high gap printing mode out of a low gap printing mode in which the distance between the nozzle and the platen is a low gap and a high gap printing mode in which the distance is a high gap greater than the low gap.

3. An ejection head that moves in a main scanning direction and has nozzles that eject ultraviolet-curable ink onto a print medium; a light source that irradiates ultraviolet light to cure the ultraviolet-curable ink; a movement mechanism that moves the print medium relative to the ejection head in a sub-scanning direction perpendicular to the main scanning direction; A controller, The controller of the image recording device performs an agitation process to agitate the ink in the ejection head without ejecting it when it receives a print job including information indicating a high gap printing mode in which printing is performed at a high gap higher than a low gap in a direction perpendicular to both the main scanning direction and the sub-scanning direction, at least when ultraviolet light is irradiated by the light source.

4. 4. The image recording apparatus according to claim 1, wherein the controller executes a purging process to forcibly discharge the ink from the nozzles after the stirring process.

5. The image recording apparatus according to claim 1 , wherein the controller executes the stirring process for the nozzles that do not eject the ink when irradiated with the ultraviolet light.

6. An image recording method using an image recording device including an ejection head that moves in a main scanning direction and has nozzles that eject ultraviolet-curable ink onto a print medium, a light source that cures the ultraviolet-curable ink, and a movement mechanism that includes a platen on which the print medium is placed and that moves the print medium relatively to the ejection head in a sub-scanning direction perpendicular to the main scanning direction, a stirring step of stirring the ink in the ejection head without ejecting the ink at least when the ink is irradiated with ultraviolet light by the light source, The stirring step is performed when the ultraviolet light is irradiated and the distance between the platen and the nozzle is greater than a pre-stored threshold value.

7. An image recording method using an image recording device including an ejection head that moves in a main scanning direction and has nozzles that eject ultraviolet-curable ink onto a print medium, a light source that cures the ultraviolet-curable ink, and a movement mechanism that includes a platen on which the print medium is placed and that moves the print medium relatively to the ejection head in a sub-scanning direction perpendicular to the main scanning direction, a stirring step of stirring the ink in the ejection head without ejecting the ink at least when the ink is irradiated with ultraviolet light by the light source, The image recording method, wherein the stirring process is performed when the printing mode is a high gap printing mode, one of a low gap printing mode in which the distance between the nozzle and the platen is a low gap, and a high gap printing mode in which the distance is a high gap larger than the low gap.

8. An image recording method using an image recording device including an ejection head that moves in a main scanning direction and has nozzles that eject ultraviolet-curable ink onto a print medium, a light source that irradiates ultraviolet light to cure the ultraviolet-curable ink, and a movement mechanism that moves the print medium relative to the ejection head in a sub-scanning direction perpendicular to the main scanning direction, An image recording method, in which, when a print job is received that includes information instructing a high gap printing mode in which printing is performed at a high gap that is higher than a low gap in a direction perpendicular to both the main scanning direction and the sub-scanning direction, at least when ultraviolet light is irradiated by the light source, a stirring process is performed to stir the ink in the ejection head without ejecting it.

9. 9. The image recording method according to claim 6, further comprising a purging step of performing a purging process to forcibly discharge the ink from the nozzles after the stirring step.

10. The image recording method according to claim 6 , wherein the stirring step is performed for the nozzles that do not eject the ink when irradiated with the ultraviolet light.

11. An image recording program to be executed by a computer in an image recording device including an ejection head that moves in a main scanning direction and has nozzles that eject ultraviolet-curable ink onto a print medium, a light source that cures the ultraviolet-curable ink, and a movement mechanism that includes a platen on which the print medium is placed and that moves the print medium relatively in a sub-scanning direction perpendicular to the main scanning direction with respect to the ejection head, causing the computer to function as an agitation unit that agitates the ink in the ejection head without ejecting the ink at least when the ink is irradiated with ultraviolet light by the light source; an image recording program that causes the stirring means to execute the stirring when the ultraviolet light is irradiated and the distance between the platen and the nozzle is greater than a pre-stored threshold value;

12. An image recording program to be executed by a computer in an image recording device including an ejection head that moves in a main scanning direction and has nozzles that eject ultraviolet-curable ink onto a print medium, a light source that cures the ultraviolet-curable ink, and a movement mechanism that includes a platen on which the print medium is placed and that moves the print medium relatively in a sub-scanning direction perpendicular to the main scanning direction with respect to the ejection head, causing the computer to function as an agitation unit that agitates the ink in the ejection head without ejecting the ink at least when the ink is irradiated with ultraviolet light by the light source; An image recording program that causes the stirring means to perform the stirring when the printing mode is a high gap printing mode out of a low gap printing mode in which the distance between the nozzle and the platen is a low gap and a high gap printing mode in which the distance is a high gap larger than the low gap.

13. An image recording program to be executed by a computer in an image recording device including an ejection head having nozzles that move in a main scanning direction and eject ultraviolet-curable ink onto a print medium, a light source that irradiates ultraviolet light to cure the ultraviolet-curable ink, and a movement mechanism that moves the print medium relative to the ejection head in a sub-scanning direction perpendicular to the main scanning direction, An image recording program that causes the computer to function as a stirring means that performs a stirring process that stirs the ink in the ejection head without ejecting it, when the computer receives a print job that includes information instructing a high gap printing mode in which printing is performed at a high gap that is higher than a low gap in a direction perpendicular to both the main scanning direction and the sub-scanning direction, at least when ultraviolet light is irradiated by the light source.

14. 14. The image recording program according to claim 11, further comprising: a program for causing the computer to function as a purging unit that executes a purging process for forcibly discharging the ink from the nozzles after the stirring.

15. 15. The image recording program according to claim 11, further comprising causing the stirring unit to execute the stirring for the nozzles that do not eject the ink when irradiated with the ultraviolet light.

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