JP2014184595A - Droplet discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet discharge device capable of preventing show-through to a recording medium.SOLUTION: A droplet discharge device includes: a base material conveying part for conveying a base material; an image forming unit having a discharge head for discharging ultraviolet curable ink as a droplet from a nozzle, and an ultraviolet irradiation part for radiating ultraviolet rays; a main scanning operation in which the image forming unit is relatively moved in a main scanning direction with respect to the base material; and a sub-scanning operation in which the base material is conveyed in a sub-scanning direction by the conveying part. When an image forming operation for forming an image on the base material by repeating the main scanning operation and the sub-scanning operation is interrupted, non-discharge irradiation scanning in which ultraviolet rays are radiated from the ultraviolet irradiation part, in a state where droplets are not discharged from the discharge head, with respect to an uncured region on the base material where the ultraviolet curable ink in an uncured state is applied is performed being interlocked with the main scanning operation.

Description

  The present invention relates to a droplet discharge device.

  Conventionally, for example, while transporting a work in a roll-to-roll system, ultraviolet curable ink is ejected toward the work, and the applied ultraviolet irradiation ink is irradiated with ultraviolet light to form an image on the work. A droplet discharge device is known (see, for example, Patent Document 1).

JP 2011-245778 A

  However, in the above apparatus, for example, when an error occurs due to ejection failure of the nozzle of the ejection head, if the ultraviolet curable ink already applied to the work is wound up in an uncured state, There has been a problem that the ultraviolet curable ink is transferred to the workpiece due to the applied pressure, and ink stains occur.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A droplet discharge apparatus according to this application example includes a substrate transport unit that transports a substrate, a discharge head that ejects ultraviolet curable ink as droplets from a nozzle, and an ultraviolet irradiation unit that irradiates ultraviolet rays. An image forming unit including: a main scanning operation for moving the image forming unit relative to the base material in a main scanning direction; and a sub-scanning operation for transporting the base material in the sub-scanning direction by the transport unit; When the image forming operation for forming an image on the base material is interrupted by repeating the main scanning operation and the sub-scanning operation, the uncured ultraviolet curable ink is applied on the base material. A non-ejection irradiation scan for irradiating ultraviolet rays from the ultraviolet irradiation section in a state in which droplets are not ejected from the ejection head to an uncured region that has been performed is performed in conjunction with the main scanning operation.

  Application Example 2 The droplet discharge device according to the application example includes an inspection unit that inspects whether or not the nozzle is defective, and when the inspection result by the inspection unit is determined to be unacceptable, The image forming operation is interrupted.

  According to this configuration, an image can be efficiently formed on the substrate by scanning the image forming unit having the ejection head and the ultraviolet irradiation unit with respect to the substrate and irradiating the ultraviolet rays while discharging the droplets. Is possible. In such a droplet discharge device, when a discharge failure such as clogging or discharge bending of the nozzle of the discharge head occurs, it becomes impossible to discharge a droplet from the nozzle, or discharge bending occurs. An image quality defect will occur. For this reason, an inspection unit for inspecting the presence or absence of nozzle ejection defects is provided. And it becomes possible to perform an appropriate treatment with respect to the ejection head based on the inspection result of the presence or absence of ejection failure of the nozzle. Here, if the inspection result of the nozzle ejection failure is acceptable, image formation may be performed by continuing droplet ejection and ultraviolet irradiation, but the nozzle ejection failure inspection result is unacceptable. If so, the image formation cannot be continued. At this time, the treatment of the uncured ultraviolet curable ink already applied on the substrate becomes a problem. Therefore, when it is determined that the inspection result of the nozzle ejection failure is unacceptable, the ejection head is not ejected in the non-ejection state (non-driving state) with respect to the uncured area to which the ultraviolet curable ink has already been applied. The irradiation unit is driven to irradiate the applied ultraviolet curable ink with ultraviolet rays. And a base material is conveyed (material removal) in the state which the ultraviolet curable ink of the non-hardened area | region hardened | cured. As a result, the base material is transported in a state where the applied ultraviolet curable ink is cured. For example, in the case where the transport of the base material is performed by winding, the pressure is applied to the base material at the time of winding the base material. Even if it is applied, the transfer of the ultraviolet curable ink to the substrate can be prevented. In addition, since it is not necessary to install an ultraviolet irradiation unit that irradiates ultraviolet rays to the uncured region separately, the apparatus configuration can be simplified.

  Application Example 3 The liquid droplet ejection apparatus according to the application example described above is characterized in that the non-ejection irradiation scanning and the sub-scanning operation are repeated.

  According to this configuration, since the ultraviolet rays are irradiated while transporting the base material, it is possible to improve the production processing capacity as compared with the case of transporting the base material after irradiating the ultraviolet rays with the transport of the base material stopped. it can.

  Application Example 4 The droplet discharge device according to the application example includes a cleaning unit that cleans the discharge head, and when it is determined that the inspection result is unacceptable based on the inspection result, The non-ejection irradiation scanning is performed after the ejection head is cleaned.

  According to this configuration, by irradiating ultraviolet rays after cleaning the ejection head, a droplet ejection operation can be performed after ultraviolet irradiation or during ultraviolet irradiation, and productivity can be improved.

  Application Example 5 In the liquid droplet ejection apparatus according to the application example, the ultraviolet curable ink is formed in a portion of the ejection head corresponding to an unimaged region where the ultraviolet irradiation ink is not applied. It is characterized by discharging.

  According to this configuration, in the ejection head, different control is performed on the part corresponding to the uncured area and the part corresponding to the unimaged area. That is, in the portion corresponding to the uncured region, only the ultraviolet irradiation unit is driven in a non-ejection state, and the ultraviolet curable ink in the uncured region is cured. On the other hand, ultraviolet curable ink is ejected at a portion corresponding to the non-image forming area (new area) of the base material to form an image. Thereby, productivity can be improved.

Schematic which shows the structure of a droplet discharge apparatus. Sectional drawing which shows the structure of an ejection head. The block diagram which shows the structure of the control part of a droplet discharge apparatus. 6 is a flowchart showing a method for controlling the droplet discharge device. FIG. 6 is a schematic diagram showing the operation of the droplet discharge device. FIG. 6 is a schematic diagram showing the operation of the droplet discharge device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each member or the like is shown differently from the actual scale so as to make each member or the like recognizable.

  First, the configuration of the droplet discharge device will be described. FIG. 1 shows a configuration of a droplet discharge device, FIG. 1A is a schematic plan view showing the entire droplet discharge device, and FIG. 1B is a schematic view showing a configuration of an image forming unit. . Note that the droplet discharge device of the present embodiment discharges, for example, ultraviolet curable ink (UV ink) as a functional liquid as droplets onto a substrate conveyed by a so-called roll-to-roll method. The apparatus configuration forms a desired image or the like on the substrate.

  As shown in FIGS. 1A and 1B, a droplet discharge device 1 includes a substrate transport unit 10 that transports a substrate W, and a discharge head 40 that discharges ultraviolet curable ink as droplets from a nozzle. The image forming unit 30 includes an ultraviolet irradiation unit 50 that irradiates ultraviolet rays, an inspection unit 60 that inspects whether there is a nozzle ejection failure, a control unit 90 that controls these members, and the like. The material of the substrate W is, for example, a polystyrene-based, olefin-based, urethane-based, ester-based, or amide-based elastomer such as polyethylene terephthalate, polyamide, or polyurethane. In the following description, the conveyance direction of the substrate W (longitudinal direction of the substrate) is the X-axis direction, and the direction orthogonal to the X-axis direction (the moving direction of the image forming unit 30) is the Y-axis direction.

  As shown in FIG. 1A, the droplet discharge device 1 includes a base material transport unit 10 that transports the base material W. Specifically, the substrate transport unit 10 includes a feeding unit 10a that feeds a long substrate W wound in a roll shape toward the stage 12 (X-axis direction), and a substrate on which an image is formed. A winding portion 10b for winding (removing material) W is provided. A motor is disposed in each of the feeding unit 10a and the winding unit 10b, and by driving the motor, the feeding unit 10a and the winding unit 10b rotate about the Y axis, and the substrate W is conveyed.

  In addition, a main scanning unit 20 that is bridged in the Y-axis direction so as to straddle the stage 12 and an image forming unit 30 that is movably mounted on the main scanning unit 20 are provided. The main scanning unit 20 includes an arch-shaped base frame 23 that extends across the stage 12 in the Y-axis direction, and a pair of Y-axis guide rails that are disposed on the base frame 23 and extend in the Y-axis direction. 24a and 24b, and a motor-driven Y-axis slider 26 that is installed in the image forming unit 30 and supports the image forming unit 30 slidably in the Y-axis direction. The main scanning movement axis is composed of a pair of Y-axis guide rails 24 a and 24 b and a Y-axis slider 26. In this case, the drive system can be constituted by a linear motor, a motor and a lead screw mechanism, or the like.

  Next, the configuration of the image forming unit 30 will be described. As shown in FIG. 1B, the image forming unit 30 includes an ejection head 40 and an ultraviolet irradiation unit 50.

  Here, first, the configuration of the ejection head 40 will be described. FIG. 2 is a cross-sectional view showing the configuration of the ejection head. As shown in FIG. 2, the ejection head 40 includes a nozzle plate 49. A plurality of nozzles 41 are formed on the nozzle plate 49. A cavity 42 communicating with the nozzle 41 is formed at a position above the nozzle plate 49 and facing the nozzle 41. The cavity 42 of the ejection head 40 is configured so that the ultraviolet curable ink I is supplied from an ink reservoir (not shown).

  Above the cavity 42, a vibration plate 44 that vibrates in the vertical direction (Z direction) (longitudinal vibration) and expands and contracts the volume in the cavity 42, and a pressurization that expands and contracts in the vertical direction to vibrate the vibration plate 44. A piezoelectric element 45 as means is provided. When the piezoelectric element 45 receives the drive signal, the piezoelectric element 45 expands, and the diaphragm 44 reduces the volume in the cavity 42. As a result, the UV curable ink I corresponding to the reduced volume is ejected as droplets D from the nozzles 41 of the ejection head 40. In this embodiment, the longitudinal vibration type piezoelectric element 45 is used as the pressurizing means. However, the piezoelectric element 45 is not particularly limited to this, for example, a bending deformation in which a lower electrode, a piezoelectric layer, and an upper electrode are laminated. A type of piezoelectric element may be used. Further, as the pressure generating means, a so-called electrostatic actuator that generates static electricity between the diaphragm and the electrode, deforms the diaphragm by electrostatic force, and discharges a droplet from the nozzle may be used. Furthermore, an ejection head having a configuration in which bubbles are generated in the nozzle using a heating element and ink is ejected as droplets by the bubbles may be used.

  The ultraviolet irradiation unit 50 includes an ultraviolet light source, and emits ultraviolet light from the ultraviolet light source. As the ultraviolet light source, for example, an LED, a high-pressure mercury lamp, a metal halide lamp, or the like can be appropriately applied. In the present embodiment, as shown in FIG. 1B, the ultraviolet irradiation unit 50 is provided on each of both sides of the ejection head 40 in the Y-axis direction. Then, while moving the image forming unit 30 in the Y-axis direction on the substrate W, the ultraviolet curable ink is discharged from the discharge head 40 toward the substrate W, and ultraviolet rays are irradiated from the two ultraviolet irradiation units 50. The UV curable ink applied to the substrate W can be cured. Thereby, an image can be efficiently formed on the substrate W.

  The inspection unit 60 inspects whether there is a discharge failure of the nozzle 41 of the discharge head 40. In the present embodiment, an attachment unit 61 for attaching (recording) the droplet D ejected from the ejection head 40 and a scanner 62 are provided. The adhesion part 61 is provided with the resin film etc., for example. The inspection unit 60 is disposed in a region that is out of the image forming region where the stage 12 and the main scanning unit 20 intersect in the Y-axis direction. When the nozzle 41 is inspected, the ejection head 40 is moved to a position facing the attachment portion 61, the droplet is ejected toward the attachment portion 61, and the droplet dot is attached to the attachment portion 61. Then, the droplet dot is scanned in the X-axis direction by the scanner 62. As a result, the attached droplet dots are captured as image information. Then, the positional relationship between the droplet dots and the corresponding nozzles 41 is calculated. Thereby, for example, since a droplet is not ejected from the nozzle 41 that has failed to eject the eyes and a droplet dot is not formed, the presence or absence of ejection failure of the nozzle 41 can be determined.

  In addition, the droplet discharge device 1 includes a cleaning unit 70. The cleaning unit 70, for example, cleans the ejection head 40 in which ejection failure or the like of the nozzle 41 has occurred and restores the ejection function. The cleaning unit 70 includes a suction unit that forcibly discharges ink from the ejection head 40, a wiping unit that wipes the surface of the nozzle plate 49 after ink suction. The cleaning unit 70 is disposed in a region that is out of the image forming region where the stage 12 and the main scanning unit 20 intersect in the Y-axis direction. In the present embodiment, the stage 12 is disposed at a position opposite to the position where the inspection unit 60 is disposed. When cleaning the ejection head 40, the ejection head 40 is moved to a position where the cleaning unit 70 is disposed.

  Next, the configuration of the control unit will be described. FIG. 3 is a block diagram illustrating a configuration of a control unit of the droplet discharge device. As shown in FIG. 3, the control unit 90 includes a command unit 100 and a drive unit 110. The command unit 100 includes a CPU (Central Processing Unit) 101 for executing various programs, a RAM (Random Access Memory) 102 for temporarily storing data and programs, various data, various programs, and the like in advance. A ROM (Read Only Memory) 103 and an interface 104 are provided. Then, the CPU 101 processes various signals input via the interface 104 based on the data in the RAM 102 and the ROM 103, and outputs a control signal to the drive unit 110 via the interface 104.

  The drive unit 110 includes various drivers, and is connected to the ejection head 40, the ultraviolet irradiation unit 50, the base material transport unit 10, the main scanning unit 20, the inspection unit 60, the cleaning unit 70, and the like. And based on the control signal of the instruction | command part 100, each member, an apparatus, etc. are controlled. For example, the presence or absence of ejection failure of the nozzle 41 of the ejection head 40 is inspected based on a predetermined driving program, and when it is determined that the inspection result is unacceptable based on the inspection result, The substrate W is irradiated with ultraviolet rays in a non-ejection state in which droplets are not ejected onto the uncured area where the uncured ultraviolet curable ink is applied, and the ultraviolet curable ink in the uncured area is cured. Can be transported.

  Next, a method for controlling the droplet discharge device will be described. FIG. 4 is a flowchart illustrating a method for controlling the droplet discharge device, and FIGS. 5 and 6 are schematic diagrams illustrating operations of the droplet discharge device. In the present embodiment, a method of controlling the droplet discharge device when performing a discharge defect inspection of the nozzle 41 during image formation will be described. In the present embodiment, a case where an image is formed by causing the ejection head 40 to scan six times (six passes) in the Y-axis direction will be described.

  First, in step S11, an image is formed on the substrate W. Specifically, as shown in FIGS. 5 and 6A, the image forming unit 30 is reciprocated in the Y-axis direction while the substrate W is conveyed in the X-axis direction. Then, ultraviolet curable ink is ejected as droplets from the nozzle 41 of the ejection head 40 of the image forming unit 30. Further, at the same time, the ultraviolet irradiating unit 50 irradiates the ultraviolet curable ink coated with ultraviolet rays. Thereby, the curing of the ink dots Pa of the ultraviolet curable ink applied on the substrate W is promoted, and the images P (P1 ′ to P5 ′) are formed.

  Here, a process until one image P is formed will be described in detail. As shown in FIG. 6A, in the present embodiment, the ejection head 40 is completed by droplet ejection of six scans (six passes) in the Y-axis direction while moving the substrate W in the X-axis direction. Two images P are formed.

  More specifically, in the first pass (first pass), droplets are ejected from the nozzle group 41a corresponding to the Ra_1 pass among the plurality of nozzles 41 of the ejection head 40, and ultraviolet rays are irradiated. As a result, an incomplete image P1 'is formed.

  Similarly, in the first pass (first pass), droplets are ejected from the nozzle group 41b corresponding to the Ra_2 pass among the plurality of nozzles 41 of the ejection head 40 and irradiated with ultraviolet rays. Thereby, an unfinished image P2 'is formed.

  Similarly, in the first pass (first pass), among the plurality of nozzles 41 of the ejection head 40, the nozzle group 41c corresponding to the Ra_3 pass, the nozzle group 41d corresponding to the Ra_4 pass, and the Ra_6 pass Droplets are ejected from the corresponding nozzle group 41e and irradiated with ultraviolet rays. As a result, unfinished images P3 ', P4', and P5 'are formed.

Similarly, in the first pass (first pass), among the plurality of nozzles 41 of the ejection head 40, droplets are ejected from the nozzle group 41f corresponding to the Ra_6 pass and ultraviolet rays are irradiated. Thereby, a completed image P6 is formed.
Next, the substrate W is transported for one pass in the X-axis direction, and the second round (second pass) is performed. FIG. 6B shows a state in which the substrate W is moved in the X-axis direction by one pass from the state of FIG. Further, FIG. 6B shows a state before the image forming unit 30 is scanned. As shown in FIG. 6B, since the substrate W is moved in the X-axis direction by one pass, the nozzle group 41b corresponds to the uncured region Ra_1 pass, and the nozzle group 41c corresponds to the uncured region Ra_2 pass. Correspondingly, the nozzle group 41d corresponds to the uncured region Ra_3 pass, the nozzle group 41e corresponds to the uncured region Ra4 pass, and the nozzle group 41f corresponds to the uncured region Ra_5 pass. The nozzle group 41a corresponds to a part (Na_01) of the non-image forming area Na.
FIG. 6C shows a state in which the image forming unit 30 has been scanned once (one pass) (a state in which one pass has been processed). As a result, the uncured region Ra_5th pass in FIG. 6B is ejected with droplets from the nozzle group 41f and irradiated with ultraviolet rays for a total of 6 passes to form a completed image P6.

  In other words, while the image P is completed, the ultraviolet rays are irradiated for six passes along with the droplet discharge. Then, the ultraviolet curable ink irradiated with ultraviolet rays for 6 passes is sufficiently cured. Accordingly, as shown in FIGS. 6A to 6C, the image P formed by executing six passes becomes a completed region Fa, and this completed region Fa can be taken up by the winding unit 10b. Do not transcribe. On the other hand, from the Ra_1 pass to the Ra_5 pass, which is the uncured region Ra, the applied UV curable ink is irradiated only once to 5 times, so the UV curable ink is in an uncured state. It is. Therefore, for example, during the scanning of the ejection head 40, the presence or absence of ejection failure of the nozzle 41 is inspected, and when it is determined to be unacceptable, the ultraviolet curable ink is wound up in the unwinding state in the winding unit 10b. The ultraviolet curable ink may be transferred to other parts of the substrate W. As shown in FIGS. 6A to 6C, the region upstream of the uncured region Ra in the transport direction of the base material W is an unimaged region where no image is formed. Na. Hereinafter, a specific control method will be described.

  Next, in step S12, it is determined whether or not to check whether there is a nozzle ejection failure. The frequency of the inspection for the presence or absence of ejection failure of the nozzles can be set as appropriate depending on, for example, the number of scans of the ejection head 40 and the type of ink to be ejected. If the inspection for the presence or absence of nozzle ejection failure is performed (YES), the process proceeds to step S12. If the inspection for the presence or absence of nozzle ejection failure is not performed (NO), the process proceeds to step S11.

  Next, in step S13, an inspection for the presence or absence of defective nozzle ejection is performed. Specifically, the ejection head 40 is moved to a position where the inspection unit 60 is disposed, and droplets are ejected toward the attachment unit 61 to apply the droplets to the attachment unit 61. Thereafter, the applied droplets are read by the scanner 62, and the presence / absence of missing dots and the ejection bend, that is, the ejection failure of the nozzle 41 is inspected.

  Next, in step S14, it is determined whether or not the inspection result is acceptable. If it is acceptable (YES), the process proceeds to step S11. If it is unacceptable (NO), the process proceeds to step S15.

  Next, in step S15, the ejection head 40 is cleaned. Specifically, the ejection head 40 is moved to the position where the cleaning unit 70 is disposed, and the ejection failure of the nozzle 41 is recovered. For example, after the ultraviolet curable ink is forcibly discharged from the ejection head 40, the surface of the nozzle plate 49 is wiped.

  Next, in step S <b> 16, processing of the uncured area Ra in which the ultraviolet curable ink is applied to the substrate W is executed. Further, the undrawn formation area Na where the ultraviolet curable ink is not applied is processed. As the treatment of the uncured region Ra, the uncured region Ra on which the uncured ultraviolet curable ink is applied on the substrate W is irradiated with ultraviolet rays in a non-ejection state in which droplets are not ejected, and uncured. The substrate W is transported in a state where the ultraviolet curable ink in the region Ra is cured. At this time, the image forming unit 30 is scanned, and the ultraviolet curable ink in the uncured region Ra is irradiated with ultraviolet rays while the substrate W is conveyed by one pass in the X-axis direction.

  On the other hand, as the processing of the non-image forming Na, the portion corresponding to the uncured area Ra in the ejection head 40 is set in the non-ejection state, and the non-image forming area Na of the substrate W to which the ultraviolet irradiation ink is not applied. UV curable ink is ejected at the corresponding part.

  This will be described more specifically with reference to FIGS. 6B and 6C. FIG. 6B shows a state in which the substrate W is moved in the X-axis direction by one pass from the state of FIG. Further, FIG. 6B shows a state before the image forming unit 30 is scanned. As shown in FIG. 6B, since the substrate W is moved in the X-axis direction by one pass, the nozzle group 41b corresponds to the uncured region Ra_1 pass, and the nozzle group 41c corresponds to the uncured region Ra_2 pass. Correspondingly, the nozzle group 41d corresponds to the uncured region Ra_3 pass, the nozzle group 41e corresponds to the uncured region Ra4 pass, and the nozzle group 41f corresponds to the uncured region Ra_5 pass. The nozzle group 41a corresponds to a part of the non-image forming area Na.

  FIG. 6C shows a state in which the image forming unit 30 has been scanned once (one pass) (a state in which one pass has been processed). At this time, unlike the case of normal image formation, the image forming unit 30 is scanned with the ejection drive of the nozzle groups 41b to 41f corresponding to the uncured region Ra stopped, and only the ultraviolet irradiation unit 50 is driven, Irradiate with ultraviolet rays. Thus, in order to process one pass, the region that was the uncured region Ra_5th pass in FIG. 6B was irradiated with a total of six passes of ultraviolet rays, and the UV curable ink that was in the uncured state was sufficiently cured. Is done. For this reason, the transfer of the ultraviolet curable ink can be prevented when the substrate W is conveyed in the X-axis direction and taken up by the take-up unit 10b.

  Further, as shown in FIG. 6C, droplets are ejected from the nozzle group 41a corresponding to a part (Na_01) of the non-image forming area Na and ultraviolet rays are irradiated. As a result, an incomplete image P ′ is formed in a part of the undrawn area Na.

  Thereafter, the above processing is executed until the uncured region Ra is processed.

  As mentioned above, according to the said embodiment, the following effects can be acquired.

  (1) When it is determined that the inspection result of the nozzle 41 for ejection failure is unacceptable, the ejection head 40 is in a non-ejection state (non-driving) with respect to the uncured area Ra to which the ultraviolet curable ink has already been applied. In the state), the ultraviolet irradiation unit 50 is driven to irradiate the applied ultraviolet curable ink with ultraviolet rays. And the base material W is conveyed (material removal) in the state which the ultraviolet curable ink of uncured area | region Ra hardened | cured. As a result, the substrate W is conveyed in a state where the applied ultraviolet curable ink is cured, so that the transfer of the ultraviolet curable ink can be prevented in the winding portion 10b.

  (2) The discharge head 40 is controlled differently in a portion corresponding to the uncured region Ra and a portion corresponding to the unimaged region Na. That is, in the portion corresponding to the uncured region Ra, only the ultraviolet irradiation unit 50 is driven in a non-ejection state, and the ultraviolet curable ink in the uncured region Ra is cured. On the other hand, ultraviolet curable ink is ejected at a portion corresponding to the non-image forming area Na of the substrate W to perform image formation. Thereby, productivity can be improved.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be added to the above-described embodiment. A modification will be described below.

  (Modification 1) In the above-described embodiment, the roll-to-roll system configuration has been described as an example of the conveyance of the base material W. However, the present invention is not limited to this configuration. For example, a configuration in which an image is formed on a rectangular sheet-like substrate and the sheet substrate is conveyed may be employed. Even if it does in this way, when a sheet base material is piled up, transfer of ultraviolet curing type ink to other sheet base materials can be prevented.

  (Modification 2) In the above-described embodiment, the uncured region processing (ultraviolet irradiation with respect to the uncured region Ra) and the unimaged region processing (unfinished image in a part of the unimaged region Na) in step S16. P ′ formation) is performed, but processing of an unimaged area is not necessarily required, and only processing of an uncured area may be performed.

  (Modification 3) In the above-described embodiment, UV irradiation on the uncured region Ra and substrate transport for transporting the substrate W in the X-axis direction are repeated while scanning the image forming unit 30 as processing of the uncured region in step S16. However, it is not always necessary to carry the substrate, and only the irradiation with the ultraviolet rays to the uncured region Ra may be performed as many times as necessary (in the above embodiment, five times or more) while scanning the image forming unit 30.

  (Modification 4) In the above embodiment, an example of the inspection result of the presence or absence of ejection failure of the nozzle is given as a trigger for interrupting image formation and performing step S16. The present invention is not limited, and the present invention can be applied in the same manner to other apparatus errors or when the user makes an emergency stop.

  DESCRIPTION OF SYMBOLS 1 ... Droplet discharge apparatus, 10 ... Base material conveyance part, 10a ... Feeding part, 10b ... Winding part, 12 ... Stage, 20 ... Main scanning part, 30 ... Image forming unit, 40 ... Discharge head, 41 ... Nozzle, 41a to 41f ... Nozzle group, 49 ... Nozzle plate, 50 ... Ultraviolet irradiation part, 60 ... Inspection part, 61 ... Adhering part, 62 ... Scanner, 70 ... Cleaning part, 90 ... Control part.

Claims (5)

A base material transport unit for transporting the base material;
An image forming unit having an ejection head that ejects ultraviolet curable ink as droplets from a nozzle, and an ultraviolet irradiation unit that irradiates ultraviolet rays;
A main scanning operation for moving the image forming unit relative to the substrate in a main scanning direction;
A sub-scanning operation for transporting the base material in the sub-scanning direction by the transport unit,
When interrupting an image forming operation for forming an image on the substrate by repeating the main scanning operation and the sub-scanning operation,
Non-ejection irradiation scanning for irradiating ultraviolet rays from the ultraviolet irradiation unit in a state where droplets are not ejected from the ejection head to an uncured region where the ultraviolet curable ink in an uncured state is applied on the substrate. , A droplet discharge device, which is performed in conjunction with the main scanning operation. The droplet discharge device according to claim 1,
An inspection unit for inspecting whether or not there is a discharge failure of the nozzle;
The liquid droplet ejection apparatus, wherein the image forming operation is interrupted when it is determined that the inspection result by the inspection unit is unacceptable. The droplet discharge device according to claim 1,
A liquid droplet ejection apparatus, wherein the non-ejection irradiation scanning and the sub-scanning operation are repeated. In the droplet discharge device according to claim 2 or 3,
A cleaning unit for cleaning the ejection head;
A droplet discharge apparatus, wherein, based on the inspection result, if it is determined that the inspection result is unacceptable, the non-ejection irradiation scan is performed after cleaning the ejection head. In the droplet discharge device according to any one of claims 1 to 4,
The droplet discharge device, wherein the ultraviolet curable ink is discharged from a portion of the discharge head corresponding to an unimaged region where the ultraviolet irradiation ink is not applied.

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