Transfer sheet forming apparatus and printing apparatus

Abstract

The present invention provides a transfer sheet forming apparatus that can suppress adverse effects caused by the separation or precipitation of components in the ink. [Solution] The transfer sheet forming apparatus forms a direct-to-film (DTF) transfer sheet including a printing medium M1 on which an image is printed and a transfer medium attached to the printing medium M1. The transfer sheet forming apparatus comprises a printing apparatus 100 that prints an image on the printing medium M1 with ultraviolet-curable ink Q, and a laminating apparatus that attaches the transfer medium to the printing medium M1 on which the image is printed. The printing apparatus 100 includes an ink storage unit 10 for storing ultraviolet-curable ink Q, a head 32 for ejecting ultraviolet-curable ink Q in an inkjet manner, and a circulation mechanism 40 for circulating ultraviolet-curable ink Q in an ink tank 31a provided upstream of the head 32.

Description

Technical Field

[0001] The present invention relates to a transfer sheet forming apparatus and a printing apparatus.

Background Art

[0002] Conventionally, printing apparatuses that perform printing by a transfer method are known. For example, Patent Document 1 discloses transferring an image printed on a transfer medium using ultraviolet curable ink by a printing apparatus to a transfer-receiving medium. This makes it possible to represent images on transfer-receiving media of various materials.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] Such printing apparatuses require complicated processes such as applying powder and heating to impart adhesiveness to the transfer medium on which an image has been printed. In addition, to omit such processes, a so-called UV-DTF method, in which an adhesive layer is previously provided on a transfer medium and an image is printed thereon, has also been attempted. In this case, since a base layer is provided on the adhesive layer and then a color image layer is printed on the base layer, missing nozzles or color unevenness occurring in the base layer become conspicuous. In particular, when the base layer is printed with a pigment-based ultraviolet curable ink containing titanium oxide as a color material, separation and sedimentation of components easily occur in the ink, so missing nozzles and color unevenness tend to occur.

[0005] In view of the above, an object of the present invention is to provide a transfer sheet forming apparatus capable of suppressing adverse effects caused by separation or sedimentation of components in ink.

Means for Solving the Problems

[0006] A transfer sheet forming apparatus according to a first aspect of the present invention is A transfer sheet forming apparatus for forming a direct-to-film (DTF) transfer sheet, comprising a printing medium on which an image is printed and a transfer medium attached to the printing medium, A printing apparatus for printing the image onto the printing medium using ultraviolet-curable ink, A laminating device that attaches the transfer medium to the printing medium on which the aforementioned image has been printed, Equipped with, The aforementioned printing apparatus, An ink storage unit for storing the aforementioned UV-curable ink, A head that ejects the aforementioned UV-curable ink using an inkjet method, The invention is characterized by including a circulation mechanism that circulates the ultraviolet-curable ink within the head or circulates the ultraviolet-curable ink in an ink tank provided upstream of the head.

[0007] With the above configuration, precipitation or separation of the ink before it is ejected from the print head is suppressed, thereby reducing the adverse effects caused by the separation or precipitation of components in the ink.

[0008] The aforementioned printing apparatus, A supply valve that controls the supply of the ultraviolet-curable ink from the ink storage unit, A supply channel for supplying the ultraviolet-curable ink, which is supplied from the ink storage unit via the supply valve, to the head, A control unit that controls the opening and closing of the supply valve and the circulation operation of the circulation mechanism, Furthermore, The circulation mechanism may also perform a circulation operation that returns the ultraviolet-curable ink in the head or the ultraviolet-curable ink in the ink tank provided in the supply channel to the upstream of the supply channel.

[0009] With the above configuration, precipitation or separation of ink before it is ejected from the head, particularly precipitation or separation of ink in the supply channel, is suppressed, thereby reducing adverse effects caused by the separation or precipitation of components in the ink.

[0010] The aforementioned circulation mechanism is A circulation channel connecting the head or the ink tank to the upstream portion of the supply channel, A circulation valve is located in the circulation channel and opens and closes the circulation channel, A filter is located downstream of the circulation valve in the circulation channel and filters the ultraviolet-curable ink flowing through the circulation channel, A circulation pump is located downstream of the filter in the circulation channel and moves the ultraviolet-curable ink from the head or the ink tank to the upstream of the supply channel via the circulation channel. Includes, The control unit may also control the circulation valve to remain open while the circulation mechanism is operating.

[0011] With the above configuration, precipitation or separation of ink before it is ejected from the head, particularly precipitation or separation of ink in the supply channel, is suppressed, thereby reducing adverse effects caused by the separation or precipitation of components in the ink.

[0012] The printing apparatus further includes a damper that absorbs pressure fluctuations of the ultraviolet-curable ink supplied to the head, The ink tank may also be the ink chamber of the damper.

[0013] With the above configuration, precipitation or separation of ink before it is ejected from the head, particularly precipitation or separation of ink within the damper, is suppressed, thereby reducing adverse effects caused by the separation or precipitation of components in the ink.

[0014] The printing apparatus may further include another circulation mechanism for circulating the ultraviolet-curable ink within the ink storage section.

[0015] With the above configuration, precipitation or separation of ink in the ink storage section is suppressed, thereby preventing adverse effects caused by the separation or precipitation of components in the ink.

[0016] The ink storage unit includes: a storage unit main body including a slot which is an insertion port provided with an ink supply port and an ink circulation port; a cartridge that stores the ultraviolet curable ink, and is configured such that when inserted into the slot, the ultraviolet curable ink can be supplied to the outside from the ink supply port and the ultraviolet curable ink can be supplied into the cartridge from the ink circulation port; and The another circulation mechanism may circulate the ultraviolet curable ink from the ink supply port to the ink circulation port.

[0017] According to the above configuration, precipitation or separation of the ink in the ink storage unit, particularly in the cartridge, is suppressed, so that adverse effects caused by separation or precipitation of components in the ink can be suppressed.

[0018] The another circulation mechanism includes: a circulation flow path that supplies the ultraviolet curable ink from the ink supply port to the ink circulation port; a filter that is disposed in the circulation flow path and filters the ultraviolet curable ink flowing through the circulation flow path; a circulation pump that is disposed on the downstream side of the filter in the circulation flow path, and moves the ultraviolet curable ink from the ink supply port to the ink circulation port via the circulation flow path; and may include these.

[0019] According to the above configuration, precipitation or separation of the ink in the ink storage unit, particularly in the cartridge, is suppressed, so that adverse effects caused by separation or precipitation of components in the ink can be suppressed.

[0020] The printing medium is supplied to the printing apparatus from a roll of the printing medium, The printing medium on which an image has been printed by the printing apparatus is sent to the laminating apparatus, The laminating apparatus receives the transfer medium from the transfer medium roll, The DTF transfer sheet, which is composed of the printing medium and the transfer medium laminated together by the laminating device, may be bundled into a roll.

[0021] With the above configuration, precipitation or separation of ink before it is ejected from the head is suppressed, thereby reducing the adverse effects caused by the separation or precipitation of components in the ink. This is particularly beneficial when printing at relatively high speeds using a roll-to-roll system while supplying printing and transfer media, as nozzle clogging and color unevenness tend to become more pronounced in such cases.

[0022] A printing apparatus according to a second aspect of the present invention is: A printing apparatus for printing an image onto a printing medium with ultraviolet-curable ink in order to form a direct-to-film (DTF) transfer sheet comprising a printing medium on which an image is printed and a transfer medium attached to the printing medium, An ink storage unit for storing the aforementioned UV-curable ink, A head that ejects the aforementioned UV-curable ink using an inkjet method, A circulation mechanism for circulating the UV-curable ink within the head or in an ink tank located upstream of the head, It is characterized by including.

[0023] With the above configuration, precipitation or separation of the ink before it is ejected from the print head is suppressed, thereby reducing the adverse effects caused by the separation or precipitation of components in the ink.

[0024] The aforementioned printing apparatus, A supply valve that controls the supply of the ultraviolet-curable ink from the ink storage unit, A supply channel for supplying the ultraviolet-curable ink, which is supplied from the ink storage unit via the supply valve, to the head, A control unit that controls the opening and closing of the supply valve and the circulation operation of the circulation mechanism, Furthermore, The circulation mechanism may also perform a circulation operation that returns the ultraviolet-curable ink in the head or the ultraviolet-curable ink in the ink tank provided in the supply channel to the upstream of the supply channel.

[0025] With the above configuration, precipitation or separation of ink before it is ejected from the head, particularly precipitation or separation of ink in the supply channel, is suppressed, thereby reducing adverse effects caused by the separation or precipitation of components in the ink.

[0026] The aforementioned circulation mechanism is A circulation channel connecting the head or the ink tank to the upstream portion of the supply channel, A circulation valve is located in the circulation channel and opens and closes the circulation channel, A filter is located downstream of the circulation valve in the circulation channel and filters the ultraviolet-curable ink flowing through the circulation channel, A circulation pump is located downstream of the filter in the circulation channel and moves the ultraviolet-curable ink from the head or the ink tank to the upstream of the supply channel via the circulation channel. Includes, The control unit may also control the circulation valve to remain open while the circulation mechanism is operating.

[0027] With the above configuration, precipitation or separation of ink before it is ejected from the head, particularly precipitation or separation of ink in the supply channel, is suppressed, thereby reducing adverse effects caused by the separation or precipitation of components in the ink.

[0028] The printing apparatus further includes a damper that absorbs pressure fluctuations of the ultraviolet-curable ink supplied to the head, The ink tank may also be the ink chamber of the damper.

[0029] With the above configuration, precipitation or separation of ink before it is ejected from the head, particularly precipitation or separation of ink within the damper, is suppressed, thereby reducing adverse effects caused by the separation or precipitation of components in the ink.

[0030] The printing apparatus may further include another circulation mechanism for circulating the ultraviolet-curable ink within the ink storage section.

[0031] With the above configuration, precipitation or separation of ink in the ink storage section is suppressed, thereby preventing adverse effects caused by the separation or precipitation of components in the ink.

[0032] The aforementioned ink storage unit is The storage unit body includes a slot which is an insertion port provided with an ink supply port and an ink circulation port, A cartridge for containing the aforementioned ultraviolet-curable ink, configured such that when inserted into the slot, the ultraviolet-curable ink can be supplied to the outside from the ink supply port and the ultraviolet-curable ink can be supplied to the inside of the cartridge from the ink circulation port, Includes, The aforementioned alternative circulation mechanism may involve circulating the ultraviolet-curable ink from the ink supply port to the ink circulation port.

[0033] With the above configuration, precipitation or separation of ink in the ink storage section, particularly in the ink within the cartridge, is suppressed, thereby preventing adverse effects caused by the separation or precipitation of components in the ink.

[0034] The aforementioned other circulation mechanism is, A circulation channel for supplying the ultraviolet-curable ink from the ink supply port to the ink circulation port, A filter is placed in the aforementioned circulation channel and filters the ultraviolet-curable ink flowing through the circulation channel, A circulation pump is located downstream of the filter in the circulation channel and moves the ultraviolet-curable ink from the ink supply port to the ink circulation port via the circulation channel. It may also include

[0035] With the above configuration, precipitation or separation of ink in the ink storage section, particularly in the ink within the cartridge, is suppressed, thereby preventing adverse effects caused by the separation or precipitation of components in the ink.

[0036] The printing apparatus receives the printing medium from the printing medium roll, The printed medium on which the image has been printed by the printing device is sent to a laminating device. The laminating apparatus receives the transfer medium from the transfer medium roll, The DTF transfer sheet, which is composed of the printing medium and the transfer medium laminated together by the laminating device, may be bundled into a roll.

[0037] With the above configuration, precipitation or separation of ink before it is ejected from the head is suppressed, thereby reducing the adverse effects caused by the separation or precipitation of components in the ink. This is particularly beneficial when printing at relatively high speeds using a roll-to-roll system while supplying printing and transfer media, as nozzle clogging and color unevenness tend to become more pronounced in such cases. [Effects of the Invention]

[0038] According to the present invention, a transfer sheet forming apparatus can be provided that can suppress adverse effects caused by the separation or precipitation of components in the ink. [Brief explanation of the drawing]

[0039] [Figure 1] A schematic side view of a transfer sheet forming apparatus according to one embodiment of the present invention. [Figure 2] A block diagram of a transfer sheet forming apparatus according to one embodiment of the present invention. [Figure 3] A schematic bottom view of the ink ejection section of a transfer sheet forming apparatus according to one embodiment of the present invention. [Modes for carrying out the invention]

[0040] (First embodiment) A transfer sheet forming apparatus 1 according to the first embodiment of the present invention will now be described. The transfer sheet forming apparatus 1 prints an image on the printed surface of a printing medium M1, which has an adhesive layer, using ultraviolet-curable ink, and then adheres a transfer medium M2 to this printed surface to form a DTF (Direct-to-Film) transfer sheet T. When performing a DTF transfer using this transfer sheet T, first, the printing medium M1 is peeled off the transfer sheet T. Then, the side of the transfer sheet T from which the printing medium M1 was peeled off is adhered to the surface to be transferred and pressed, for example, by heat pressing. Finally, when the transfer medium M2 is peeled off the surface to be transferred, the image is transferred to the surface to be transferred.

[0041] (Configuration of the transfer sheet forming apparatus 1) As shown in Figure 1, the transfer sheet forming apparatus 1 comprises a printing apparatus 100 and a laminating apparatus 200. The printing apparatus 100 is supplied with printing medium M1 from a roll of printing medium M1, and the printing medium M1 on which the image has been printed is then sent to the laminating apparatus 200. The laminating apparatus 200 is also supplied with transfer medium M2 from a roll of transfer medium M2, and the transfer sheet T, which is composed of the printing medium M1 and transfer medium M2 laminated together in the laminating apparatus 200, is then rolled up, for example, by an electric winding machine (not shown).

[0042] Printing medium 1 is a film made of polyethylene terephthalate (PET), polypropylene (PP), polycarbonate (PC), polyvinyl chloride (PVC), polyester (PE), etc., for example, a PET film, and has an adhesive layer on the printing surface. Printing medium 1 may also be provided with a release layer to facilitate peeling from the transfer sheet T. Transfer medium M2 is made of polyethylene terephthalate (PET), polypropylene (PP), polycarbonate (PC), polyvinyl chloride (PVC) The transfer medium M2 may be a film such as glycol-modified polyethylene terephthalate (PETG), for example, a PET film. A release layer may be provided on the transfer medium M2 to facilitate the transfer of the image to the transfer surface.

[0043] (Printing device 100) As shown in Figures 1 and 2, the printing apparatus 100 comprises a transport unit R, an ink storage unit 10, an ink supply system 20, an ink ejection unit 30, circulation mechanisms 40 and 50, a control unit 60, a storage unit 70, and a human-machine interface (MMI) 80. The printing apparatus 100 is an inkjet type printing apparatus that prints an image on a printing medium M1 delivered by the transport unit R using ultraviolet-curable ink Q stored in the ink storage unit 10. The details of the components of the printing apparatus 100 will be described below.

[0044] (Ink storage section 10) As shown in Figure 2, the ink storage unit 10 houses ink Q, which is an ultraviolet-curable inkjet ink, and supplies ink Q to the outside. Ink Q is, for example, an ink in which components precipitate or separate over time, and is, for example, an ink containing colorants with relatively large particle sizes. An example of such an ink is a white ink containing titanium dioxide particles as a colorant. The ink storage unit 10 comprises a storage unit body 11 and at least one cartridge 12. The storage unit body 11 is provided with a slot 11a, which is an insertion opening with an ink supply port 11b and an ink circulation port 11c. For example, the ink supply port 11b is configured to connect to the bottom of the cartridge 12 which is lower along the direction of gravity, and the ink circulation port 11c is configured to connect to the top of the cartridge 12 which is higher along the direction of gravity. A cartridge 12 containing ink Q is removably inserted into the slot 11a.

[0045] Cartridge 12 contains a sealed container of ink Q. Cartridge 12 is the ink supply source that supplies ink Q. When inserted into slot 11a, cartridge 12 can supply ink Q to the outside through the ink supply port 11b and can supply ink Q to the inside through the ink circulation port 11c.

[0046] (Ink supply system 20) The ink supply system 20 includes a supply valve 21 and a supply channel 22. As shown in Figure 2, the supply valve 21 is connected to the cartridge 12. The supply of ink Q from the cartridge 12 to the outside is controlled by opening and closing the supply valve 21. The opening and closing of the supply valve 21 is controlled by the control unit 60. The supply valve 21 may be enclosed within the ink storage unit 10.

[0047] The supply channel 22 is a channel for ink Q that is piped to supply ink Q from the cartridge 12 to the ink ejection section 30 via the supply valve 21.

[0048] (Ink ejection section 30) As shown in Figures 2 and 3, the ink ejection unit 30 includes a damper 31, a head 32, and an ultraviolet irradiation device 33. The damper 31 supplies ink Q, which is supplied from the ink storage unit 10 via the ink supply system 20, to the head 32 and absorbs pressure fluctuations of the ink supplied to the head 32. In the supply channel 22, for example, due to the difference in water head between the ink storage unit 10 and the damper 31, ink Q flows in the supply direction D1 from the ink storage unit 10 toward the damper 31. The supply channel 22 may have a piping structure in which it branches into multiple channels at the connection point with the damper 31 and connects to the damper 31.

[0049] The damper 31 has an ink chamber 31a that stores the ink Q supplied from the supply channel 22. The damper 31 supplies the ink Q stored in the ink chamber 31a to the head 32. More specifically, the damper 31 supplies the ink Q to the head 32 while adjusting the internal pressure of the head 32 to a predetermined slight negative pressure that is slightly lower than atmospheric pressure. The damper 31 forms a meniscus surface Qa of ink Q at the tip of the nozzle 32a of the head 32, such that it is a curved surface that is convex upward (concave toward the printing medium M1).

[0050] The print head 32 has multiple nozzles 32a that eject ink Q using an inkjet method. The print head 32 is provided to be movable in the main scanning direction (left and right directions perpendicular to the front-to-back and up-and-down directions in Figure 1). The operation of the print head 32 is controlled by the control unit 60.

[0051] As shown in Figure 3, at least two ultraviolet irradiation devices 33 are provided so as to sandwich the head 32 along the main scanning direction. The ultraviolet irradiation devices irradiate the ink Q that has been ejected from the nozzle 32a of the head 32 and landed on the printing medium M1 with ultraviolet light, thereby curing the ink Q. The operation of the ultraviolet irradiation devices 33 is controlled by the control unit 60.

[0052] (Circulation mechanism 40) The circulation mechanism 40 circulates the ink Q supplied to the damper 31 of the ink discharge section 30 back to the supply channel 22 downstream of the supply valve 21 and upstream of the supply channel 22. As shown in Figure 2, the circulation mechanism 40 comprises a circulation channel 41, a circulation valve 42, a filter 43, and a circulation pump 44. The circulation channel 41 connects the ink chamber 31a of the damper 31 to the upstream portion (confluence point 22a) of the supply channel 22. The ink Q stored in the ink chamber 31a can flow into the circulation channel 41. The circulation channel 41 may be configured as a piping structure in which multiple channels are connected to the ink chamber 31a and merge into one.

[0053] The circulation valve 42 is located in the circulation channel 41 and opens and closes the circulation channel 41. When the circulation valve 42 is open, ink Q can flow through the circulation channel 41, and when the circulation valve 42 is closed, ink Q cannot flow through the circulation channel 41. The opening and closing of the circulation valve 42 is controlled by the control unit 60. If the circulation channel 41 connected to the damper 31 has a structure in which it branches into multiple channels, it is desirable to provide a circulation valve 42 in each of the branched channels.

[0054] The filter 43 is positioned downstream of the circulation valve 42 in the circulation channel 41. The filter 43 filters the ink Q flowing through the circulation channel 41 to remove foreign matter from the ink Q.

[0055] The circulation pump 44 is located downstream of the circulation valve 42 in the circulation passage 41. The circulation pump 44 is located further downstream of the filter 43, which is located downstream of the circulation valve 42 in the circulation passage 41. The circulation pump 44 generates a pressure difference, thereby moving ink Q from the damper 31 side to the upstream of the supply passage 22 via the circulation passage 41.

[0056] By operating the circulation pump 44 with the circulation valve 42 open, ink Q flows from the damper 31 into the circulation channel 41, and the incoming ink Q flows through the circulation channel 41 along the circulation direction D2. The ink Q flows through the circulation valve 42, filter 43, and circulation pump 44 to the downstream side of the supply valve 21 in the supply channel 22, i.e., to the confluence point 22a. In this way, the ink Q circulates through the supply channel 22 and the circulation channel 51 from the confluence point 22a to the ink discharge section 30. If this circulation is performed periodically at appropriate intervals, sedimentation and separation of the ink Q in the supply channel 22 can be prevented.

[0057] (Circulation mechanism 50) The circulation mechanism 50 performs a circulation operation to circulate ink within the cartridge 12. As shown in Figure 2, the circulation mechanism 50 comprises a circulation channel 51, a filter 52, and a circulation pump 53. The circulation channel 51 connects the ink circulation port 11c to a portion of the supply channel 22 upstream of the supply valve 21 (confluence point 22b). The ink Q stored in the ink storage unit 10 can flow into the circulation channel 51. Multiple circulation channels 51 may be connected to the ink storage unit 10 and merge into one. Furthermore, the connection of the circulation channel 51 is arbitrary as long as ink Q can be supplied from the ink supply port 11b to the ink circulation port 11c, and instead of connecting to the confluence point 22b, it may be connected to the cartridge 12 via an ink supply port provided in the ink storage unit 10 separately from the ink supply port 11b.

[0058] The filter 52 is located in the circulation channel 51 and filters the ink Q flowing through the circulation channel 51 to remove foreign matter from the ink Q.

[0059] The circulation pump 53 is installed downstream of the filter 52 in the circulation passage 51. The circulation pump 53 generates a pressure difference, thereby moving the ink Q from the ink supply port 11b to the ink circulation port 11c via the circulation passage 51.

[0060] Regardless of whether the supply valve 21 is open or closed, for example, by operating the circulation pump 53 with the supply valve 21 closed, ink Q flows from the ink supply port 11b through the confluence point 22b into the circulation channel 51, and the incoming ink Q flows through the circulation channel 51 along the circulation direction D3. The ink Q flows through the filter 52 and the circulation pump 53 into the ink circulation port 11c. In this way, the ink Q circulates through a part of the supply channel 22, the circulation channel 51, and within the cartridge 12. If this circulation is performed regularly at appropriate intervals, sedimentation and separation of the ink Q within the cartridge 12 are prevented.

[0061] Furthermore, each of the above-mentioned supply valve 21, damper 31, circulation valve 42, circulation pump 44, and circulation pump 53 is equipped with a check valve (not shown). These check valves prevent the ink Q from flowing back in the intended direction of flow.

[0062] (Control unit 60) As shown in Figure 2, the control unit 60 controls the operation of the entire printing apparatus 100. For example, the control unit 60 controls the supply operation by opening and closing the supply valve 21 and the circulation operation of the circulation mechanisms 40 and 50. The control unit 60 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The CPU is also called a central processing unit, central computing unit, processor, microprocessor, microcomputer, DSP (Digital Signal Processor), etc., and functions as a central computing unit that performs processing and calculations related to the control of the printing apparatus 100. In the control unit 60, the CPU reads programs and data stored in ROM and uses RAM as a work area to comprehensively control the printing apparatus 100.

[0063] (Storage unit 70) As shown in Figure 2, the storage unit 70 is equipped with non-volatile semiconductor memory such as flash memory, EPROM (Erasable Programmable ROM), and EEPROM (Electrically Erasable Programmable ROM), and plays the role of a so-called secondary storage device or auxiliary storage device. The storage unit 70 stores programs and data used by the control unit 60 to execute various processes. The storage unit 70 also stores data generated or acquired by the control unit 60 as a result of executing various processes.

[0064] (Human-machine interface 80) As shown in Figure 2, the man-machine interface (MMI) 80 displays various images according to the control of the control unit 60. The MMI 80 includes, for example, a touchscreen, a liquid crystal display, etc., as image display means. The MMI 80 receives various operations from the user and supplies information indicating the content of the received operations to the control unit 60. For this purpose, the MMI 80 includes, for example, a touchscreen, buttons, levers, etc., as input means.

[0065] (Functions of the control unit 60) Next, the main functions of the control unit 60 will be described in detail. As shown in Figure 2, the control unit 60 functionally comprises a print operation control unit 61, a supply operation control unit 62, and circulation operation control units 63 and 64. Each of these functions is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the ROM or storage unit 70. The CPU then realizes each of these functions by executing the programs stored in the ROM or storage unit 70.

[0066] (Print operation control unit) As shown in Figure 2, the printing operation control unit 61 outputs a control signal S1 to the head 32 to control the operation of the head 32. The printing operation control unit 61 also outputs a control signal S2 to the transport unit R to control the operation of the transport unit R that transports the printing medium M1. Furthermore, the printing operation control unit 61 outputs a control signal S3 to the ultraviolet irradiation device 33 to control the operation of the ultraviolet irradiation device 33. The printing operation control unit 61 controls the printing operation by the head 32, the ultraviolet irradiation device 33, and the transport unit R based on the output of control signals S1, S2, and S3.

[0067] The printing operation control unit 61 receives image data to be printed from a higher-level device (not shown). The printing operation control unit 61 forms a dot pattern of ink Q corresponding to the input image data. When the MMI 80 inputs a print start command, the printing operation control unit 61 outputs control signals S1 and S2 to move the head 32 in the main scanning direction, while relatively moving the transport unit R on which the printing medium M1 is placed in a sub-scanning direction (front-back direction in Figure 1) perpendicular to the main scanning direction, so that the dot pattern is formed on the printing medium M1, and ejects ink Q from the nozzle 32a. In addition, the printing operation control unit 61 outputs a control signal S3 to cure the ink Q that has landed on the printing medium M1, and irradiates ultraviolet light from the ultraviolet irradiation device 33 as one of the ultraviolet irradiation devices 33 passes over the ink Q that has landed on the printing medium M1. For example, when the head 32 moves in one direction along the main scanning direction (to the right in Figure 3), the print operation control unit 61 irradiates ultraviolet light from the ultraviolet irradiation device 33 located behind the head 32 (to the left in Figure 3) when viewed from that direction. When the head 32 moves in the opposite direction along the main scanning direction (to the left in Figure 3), the print operation control unit 61 irradiates ultraviolet light from the ultraviolet irradiation device 33 located behind the head 32 (to the right in Figure 3) when viewed from that direction. This allows printing to be performed on the printing medium M1. When printing is not being performed, the print operation control unit 61 places the head 32 in a predetermined standby position.

[0068] (Supply operation control unit) As shown in Figure 1, the supply operation control unit 62 outputs a control signal S4 to control the opening and closing operation of the supply valve 21. Based on the output of the control signal S4, the supply operation control unit 62 controls the supply operation of ink Q from the cartridge 12 to the head 32. When supplying ink Q from the cartridge 12 to the head 32, the supply operation control unit 62 opens the supply valve 21. When stopping this supply, for example, when the amount of ink Q in the cartridge 12 becomes zero or close to zero, the supply operation control unit 62 closes the supply valve 21.

[0069] The supply operation can be performed whether or not a printing operation is in progress. In other words, the supply operation and the printing operation are performed simultaneously and asynchronously.

[0070] (Circulation operation control unit 63) The circulation operation by the circulation mechanism 40 is performed to prevent the components of ink Q from settling in the supply channel 22, ink chamber 31a, etc., and to prevent uneven concentration of ink Q. In other words, the circulation operation is one of the maintenance operations of the printing apparatus 100. The circulation operation control unit 63 causes the circulation mechanism 50 to perform the circulation operation at regular intervals. Specifically, the circulation operation control unit 63 opens the circulation valve 42 and then drives the circulation pump 44 to perform the circulation operation.

[0071] As shown in Figure 2, the circulation control unit 63 outputs a control signal S5 to the circulation valve 42 to control the opening and closing operation of the circulation valve 42. The circulation control unit 63 controls the opening and closing operation of the circulation valve 42 based on the control signal S5. The circulation control unit 63 outputs a control signal S6 to the circulation pump 44 to control the operation of the circulation pump 44. The circulation control unit 63 controls the operation of the circulation pump 44 based on the control signal S6. In other words, the circulation control unit 63 controls the circulation operation by opening and closing the circulation valve 42 and operating the circulation pump 44 based on the control signals S5 and S6.

[0072] The circulation control unit 63 periodically causes the circulation mechanism 40 to perform a circulation operation. The circulation operation is performed simultaneously and asynchronously with the printing operation. That is, the circulation control unit 63 can cause the circulation mechanism 40 to perform a circulation operation regardless of whether the printing operation control unit 61 is performing a printing operation or not.

[0073] The circulating operation is performed simultaneously and in coordination with the supply operation. That is, the circulating operation control unit 63 and the supply operation control unit 62 are capable of performing the circulating operation and the supply operation simultaneously, and both operations are performed in coordination between the circulating operation control unit 63 and the supply operation control unit 62. This coordinated operation can be executed simultaneously and asynchronously with the printing operation. That is, the coordinated operation of the circulating operation control unit 63 and the supply operation control unit 62 can be performed whether or not printing is in progress.

[0074] (Circulation control unit 64) The circulation operation by the circulation mechanism 50 is performed to prevent the components of ink Q from settling in the supply channel 22, cartridge 12, etc., and to prevent uneven concentration of ink Q. In other words, the circulation operation is one of the maintenance operations of the printing device 100. The circulation operation control unit 64 causes the circulation mechanism 50 to perform the circulation operation at regular intervals. Specifically, the circulation operation control unit 64 drives the circulation pump 53 to perform the circulation operation.

[0075] As shown in Figure 2, the circulation control unit 64 outputs a control signal S7 to the circulation pump 53 to control the operation of the circulation pump 53. The circulation control unit 64 controls the operation of the circulation pump 53 based on the control signal S7. In other words, the circulation control unit 64 controls the circulation operation by operating the circulation pump 53 in accordance with the control signal S7.

[0076] The circulation control unit 64 periodically causes the circulation mechanism 50 to perform a circulation operation. The circulation operation is performed simultaneously and asynchronously with the printing operation. That is, the circulation control unit 64 can cause the circulation mechanism 50 to perform a circulation operation regardless of whether the printing operation control unit 61 is performing a printing operation or not.

[0077] The circulating operation is performed simultaneously and in coordination with the supply operation. That is, the circulating operation control unit 64 and the supply operation control unit 62 are capable of performing the circulating operation and the supply operation simultaneously, and both operations are performed in coordination between the circulating operation control unit 64 and the supply operation control unit 62. This coordinated operation can be executed simultaneously and asynchronously with the printing operation. That is, the coordinated operation of the circulating operation control unit 64 and the supply operation control unit 62 can be performed whether or not printing is in progress.

[0078] The circulating operation by the circulating mechanism 40 and the circulating operation by the circulating mechanism 50 can be performed simultaneously and asynchronously. The circulating operation by either the circulating mechanism 40 or 50 can be performed regardless of whether the circulating operation by the other is being performed.

[0079] (Laminating machine 200) As shown in Figure 1, the laminating device 200 laminates the transfer medium M2, supplied from a roll of transfer medium M2, onto the printing medium M1, supplied from the printing device 100, which has an image printed on its surface, for example, by cold lamination or hot lamination. The transfer sheet T, consisting of the printing medium M1 and transfer medium M2 laminated by the laminating device 200, is rolled up by a winding machine (not shown). The lamination operation by the laminating device 200 may be performed simultaneously and in coordination with the printing operation. For this purpose, the laminating device 200 may be electronically controlled and controlled by a control unit 60.

[0080] (Effects of the present invention) In conventional UV-DTF printing, a base layer is applied on top of the adhesive layer, and then the color image layer is printed on top of that base layer. As a result, nozzle cutouts and color unevenness in the base layer are noticeable. In particular, when the base layer is printed with a pigment-based UV-curing ink that uses titanium dioxide as a colorant, the components are prone to separation and precipitation in the ink, which can easily lead to nozzle cutouts and color unevenness.

[0081] According to the above embodiment, the circulation mechanism 40 circulates the ink Q in the ink chamber 31a of the damper 31, and the circulation mechanism 50 circulates the ink Q in the cartridge 12, thereby suppressing the separation or precipitation of components in the ink Q. This suppresses adverse effects caused by the separation or precipitation of components in the ink Q, such as nozzle clogging or color unevenness.

[0082] (modified version) The configuration of the transfer sheet forming apparatus 1 is arbitrary, except that it includes at least one of the circulation mechanisms 40 and 50, as long as it can form a DTF transfer sheet T which includes a printing medium M1 on which an image is printed and a transfer medium M2 attached thereon.

[0083] For example, in the above embodiment, a printing medium M1 with an adhesive layer already provided is used, but instead, a printing medium M1 without an adhesive layer may be used. In this case, the transfer sheet forming apparatus 1 is provided with an adhesive layer application device that applies the adhesive layer to the printing surface of the printing medium M1 before the printing device 100 prints the image onto the printing medium M1. Alternatively, instead of an adhesive layer application device, the printing device 100 may be configured to print the adhesive layer using adhesive ink, and the printing device 100 may apply the adhesive layer to the entire printing surface of the printing medium M1, or at least to the area where the image is to be printed, before the printing device 100 prints the image.

[0084] The printing device 100 can be configured in the same way as a conventional ultraviolet inkjet printer, except that it includes at least one of the circulation mechanisms 40 and 50, to print an image with ultraviolet-curable ink and cure the ink with an ultraviolet irradiation device. For example, in the ink storage unit 10, a different type of replaceable or fixed ink storage container, such as a replaceable or fixed bottle, may be used instead of the cartridge 12. The printing device 100 may also be configured to print an image using multiple types, in particular, multiple colors of ultraviolet-curable ink. In this case, among the cartridges 12 or ink storage containers that store various inks, one or both of the circulation mechanisms 40 and 50 may be provided only in the cartridge 12 or ink storage container that stores ink that is highly likely to settle or separate, for example, only in the cartridge 12 or ink storage container that stores white ink.

[0085] The circulation mechanism 40 may be made independent of the supply channel 22. For example, the downstream end of the circulation channel 41 of the circulation mechanism 40 may be connected to the ink chamber 31a of the damper 31 instead of the confluence point 22a of the supply channel 22. In this case, an additional circulation mechanism may be provided to circulate the ink Q in the supply channel 22, or the circulation mechanism 50 may be configured to circulate the ink Q in the supply channel 22.

[0086] The circulation mechanism 40 circulates the ink Q in the ink chamber 31a of the damper 31. Alternatively, the circulation mechanism 40 may be configured to circulate the ink Q in another type of ink tank (a so-called sub-tank) located upstream of the head 32, particularly directly before it, in order to supply ink Q to the head 32. In addition to the circulation mechanism 40 that circulates the ink Q in the ink chamber 31a of the damper 31, a circulation mechanism 40 for circulating the ink Q in such another type of ink tank may also be provided. The other type of ink tank may be located in the middle of the supply channel 22, or in the middle of another channel located between the ink storage unit 10 and the head 32. If the other type of ink tank is located in the middle of this other channel, the downstream end of the circulation channel 41 of the circulation mechanism 40 may be connected to this channel between the ink storage unit 10 and the other type of ink tank, or to the ink tank, instead of the confluence point 22a of the supply channel 22.

[0087] Furthermore, while the circulation mechanism 40 circulates the ink Q in the ink chamber 31a of the damper 31, the circulation mechanism 40 may instead be configured to circulate the ink Q in the head 32, for example, the ink Q in the ink storage section of the head 32. In addition to the circulation mechanism 40 that circulates the ink Q in the ink chamber 31a of the damper 31, a circulation mechanism 40 that circulates the ink Q in the head 32 may also be provided. Both the upstream and downstream ends of the circulation channel 41 of such a circulation mechanism 40 may be connected to the head 32, for example, to the ink storage section of the head 32, or only the upstream end of the circulation channel 41 may be connected to the head 32, and the downstream end of the circulation channel 41 may be connected to any channel that supplies ink Q from the ink storage section 10 to the head 32, for example, the junction 22a of the supply channel 22.

[0088] The configuration of the circulation mechanisms 40 and 50 is arbitrary as long as the ink Q can be circulated within the main circulation area, such as the ink tank located upstream of the head 32 (for example, the ink chamber 31a of the damper 31, or other types of ink tanks located directly in front of the head 32), the head 32 (for example, the ink storage section of the head 32), or the ink storage section 10 (for example, the cartridge 12 or other ink storage container). In particular, the configuration of the flow path for circulating the ink Q is not limited to those described in the above embodiments and modifications.

[0089] If the circulation mechanism 50 is omitted, the cartridge 12 or other replaceable ink storage container may be shaken well before being installed in the ink storage unit 10. To encourage the user to take this action, the image display means of the MMI 80 may display a message indicating that the cartridge 12 or other replaceable ink storage container should be shaken well before being installed in the ink storage unit 10 when it is necessary to install it in the ink storage unit 10. For example, this message may be displayed when the cartridge 12 or other replaceable ink storage container is removed from the ink storage unit 10.

[0090] The distance between the lower surface or nozzle surface of the head 32 and the printing medium M1 on the transport unit R, in particular the shortest distance, and consequently the distance between the lower surface or nozzle surface of the head 32 and the transport unit R, in particular the shortest distance, should be such that the adhesive layer of the printing medium M1 does not adhere to the lower surface or nozzle surface of the head 32. For example, the distance between the lower surface or nozzle surface of the head 32 and the printing medium M1 should be in the range of 2 to 3 mm.

[0091] The features described in the above embodiments and modifications can be combined in any way, as long as they do not contradict each other. [Explanation of Symbols]

[0092] 100 Printing equipment 10 Ink storage section 11 Storage Unit 11a slot 11b Ink supply port 11c Ink circulation port 12 cartridges 20. Ink supply system 21 Supply valve 22 Supply channel 30 Ink ejection section 31 Damper 31a Ink chamber 32 heads 32a Nozzle 40, 50 Circulation mechanism 41, 51 Circulation channels 42 Circulation valve 43, 52 filters 44, 53 Circulation pumps 60 Control Unit 61 Printing Operation Control Unit 62 Supply Operation Control Unit 63, 64 Circulation Operation Control Unit 70 Memory section 80. Human-Machine Interface M1 print media M2 transfer medium Q Ink Qa Meniscus R Conveyor Unit S1, S2, S3, S4, S5, S6, S7 control signal T Transfer Sheet

Claims

1. A transfer sheet forming apparatus for forming a direct-to-film (DTF) transfer sheet, comprising a printing medium on which an image is printed and a transfer medium attached to the printing medium, A printing apparatus for printing the image onto the printing medium using ultraviolet-curable ink, A laminating device that attaches the transfer medium to the printing medium on which the aforementioned image has been printed, Equipped with, The aforementioned printing apparatus, An ink storage unit for storing the aforementioned UV-curable ink, A head that ejects the aforementioned UV-curable ink using an inkjet method, A circulation mechanism for circulating the UV-curable ink within the head or in an ink tank located upstream of the head, including, Transfer sheet forming apparatus.

2. The aforementioned printing apparatus, A supply valve that controls the supply of the ultraviolet-curable ink from the ink storage unit, A supply channel for supplying the ultraviolet-curable ink, which is supplied from the ink storage unit via the supply valve, to the head, A control unit that controls the opening and closing of the supply valve and the circulation operation of the circulation mechanism, Furthermore, The circulation mechanism performs a circulation operation to return the ultraviolet-curable ink in the head or the ultraviolet-curable ink in the ink tank provided in the supply channel to the upstream of the supply channel. The transfer sheet forming apparatus according to claim 1.

3. The aforementioned circulation mechanism is A circulation channel connecting the head or the ink tank to the upstream portion of the supply channel, A circulation valve is located in the circulation channel and opens and closes the circulation channel, A filter is located downstream of the circulation valve in the circulation channel and filters the ultraviolet-curable ink flowing through the circulation channel, A circulation pump is located downstream of the filter in the circulation channel and moves the ultraviolet-curable ink from the head or the ink tank to the upstream of the supply channel via the circulation channel. Includes, The control unit controls the circulation valve to remain open while the circulation mechanism is operating. The transfer sheet forming apparatus according to claim 2.

4. The printing apparatus further includes a damper that absorbs pressure fluctuations of the ultraviolet-curable ink supplied to the head, The ink tank is the ink chamber of the damper. A transfer sheet forming apparatus according to any one of claims 1 to 3.

5. The transfer sheet forming apparatus according to claim 1 or 2, further comprising another circulation mechanism for circulating the ultraviolet-curable ink within the ink storage section of the printing apparatus.

6. The aforementioned ink storage unit is The storage unit body includes a slot which is an insertion port provided with an ink supply port and an ink circulation port, A cartridge for containing the aforementioned ultraviolet-curable ink, configured such that when inserted into the slot, the ultraviolet-curable ink can be supplied to the outside from the ink supply port and the ultraviolet-curable ink can be supplied to the inside of the cartridge from the ink circulation port, Includes, The aforementioned alternative circulation mechanism circulates the ultraviolet-curable ink from the ink supply port to the ink circulation port. The transfer sheet forming apparatus according to claim 5.

7. The aforementioned other circulation mechanism is, A circulation channel for supplying the ultraviolet-curable ink from the ink supply port to the ink circulation port, A filter is placed in the aforementioned circulation channel and filters the ultraviolet-curable ink flowing through the circulation channel, A circulation pump is located downstream of the filter in the circulation channel and moves the ultraviolet-curable ink from the ink supply port to the ink circulation port via the circulation channel. including, The transfer sheet forming apparatus according to claim 6.

8. The printing apparatus receives the printing medium from the printing medium roll, The printing medium on which the image has been printed by the printing device is sent to the laminating device. The laminating apparatus receives the transfer medium from the transfer medium roll, The DTF transfer sheet, which is composed of the printing medium and the transfer medium laminated together by the laminating device, is bundled into a roll. The transfer sheet forming apparatus according to claim 1.

9. A printing apparatus for printing an image onto a printing medium with ultraviolet-curable ink in order to form a direct-to-film (DTF) transfer sheet comprising a printing medium on which an image is printed and a transfer medium attached to the printing medium, An ink storage unit for storing the aforementioned UV-curable ink, A head that ejects the aforementioned UV-curable ink using an inkjet method, A circulation mechanism for circulating the UV-curable ink within the head or in an ink tank located upstream of the head, including, Printing device.

10. The aforementioned printing apparatus, A supply valve that controls the supply of the ultraviolet-curable ink from the ink storage unit, A supply channel for supplying the ultraviolet-curable ink, which is supplied from the ink storage unit via the supply valve, to the head, A control unit that controls the opening and closing of the supply valve and the circulation operation of the circulation mechanism, Furthermore, The circulation mechanism performs a circulation operation to return the ultraviolet-curable ink in the head or the ultraviolet-curable ink in the ink tank provided in the supply channel to the upstream of the supply channel. The printing apparatus according to claim 9.

11. The aforementioned circulation mechanism is A circulation channel connecting the head or the ink tank to the upstream portion of the supply channel, A circulation valve is located in the circulation channel and opens and closes the circulation channel, A filter is located downstream of the circulation valve in the circulation channel and filters the ultraviolet-curable ink flowing through the circulation channel, A circulation pump is located downstream of the filter in the circulation channel and moves the ultraviolet-curable ink from the head or the ink tank to the upstream of the supply channel via the circulation channel. Includes, The control unit controls the circulation valve to remain open while the circulation mechanism is operating. The printing apparatus according to claim 10.

12. The printing apparatus further includes a damper that absorbs pressure fluctuations of the ultraviolet-curable ink supplied to the head, The ink tank is the ink chamber of the damper. A printing apparatus according to any one of claims 9 to 11.

13. The printing apparatus according to claim 9 or 11, further comprising another circulation mechanism for circulating the ultraviolet-curable ink within the ink storage section.

14. The aforementioned ink storage unit is The storage unit body includes a slot which is an insertion port provided with an ink supply port and an ink circulation port, A cartridge for containing the aforementioned ultraviolet-curable ink, configured such that when inserted into the slot, the ultraviolet-curable ink can be supplied to the outside from the ink supply port and the ultraviolet-curable ink can be supplied to the inside of the cartridge from the ink circulation port, Includes, The aforementioned alternative circulation mechanism circulates the ultraviolet-curable ink from the ink supply port to the ink circulation port. The printing apparatus according to claim 13.

15. The aforementioned other circulation mechanism is, A circulation channel for supplying the ultraviolet-curable ink from the ink supply port to the ink circulation port, A filter is placed in the aforementioned circulation channel and filters the ultraviolet-curable ink flowing through the circulation channel, A circulation pump is located downstream of the filter in the circulation channel and moves the ultraviolet-curable ink from the ink supply port to the ink circulation port via the circulation channel. including, The printing apparatus according to claim 14.

16. The printing apparatus receives the printing medium from the printing medium roll, The printed medium on which the image has been printed by the printing device is sent to a laminating device. The laminating apparatus receives the transfer medium from the transfer medium roll, The DTF transfer sheet, which is composed of the printing medium and the transfer medium laminated together by the laminating device, is bundled into a roll. The printing apparatus according to claim 9.

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