Head maintenance system, printing system, and head maintenance method

Abstract

Provided are a head maintenance system, a printing system, and a head maintenance method, which make it possible to realize preferable cleaning of a nozzle surface and prevent damage to the nozzle surface. The present invention comprises: a wiping device (3) that includes a wiping sheet (10) for wiping a nozzle surface (52) of an ink-jet head (50); relative motion devices (2, 3) that relatively move the ink-jet head and the wiping sheet; and a pressing device (18, 56) that presses the wiping sheet onto the nozzle surface. The wiping device includes the wiping sheet, which has a compression linearity value of 0.3 or more and less than 0.6, as measured by use of a compression testing machine.

Description

[Technical Field]

[0001] The present invention relates to a head maintenance system, a printing system, and a head maintenance method. [Background technology]

[0002] In an inkjet printing apparatus, ink mist and the like may adhere to a nozzle surface on which nozzle openings of an inkjet head are formed, and ejection abnormalities may occur in the inkjet head due to the adhesion of ink mist and the like to the nozzle surface.

[0003] Patent Document 1 describes an inkjet printing device that applies a cleaning liquid to the nozzle surface and wipes off any deposits that have adhered to the nozzle surface using an absorbing member that absorbs the deposits. When wiping the nozzle surface with the absorbing member, the device described in this document applies a load of 8 grams per centimeter or more and 150 grams per centimeter or less to press the absorbing member against the nozzle surface. This achieves excellent nozzle surface cleaning performance.

[0004] Patent Document 2 describes a range of 50 to 500 grams of pressure of the absorbing member against the nozzle surface in a device similar to that described in Patent Document 1. The same document also describes a preferred range of pressure of 75 to 300 grams of pressure.

[0005] Patent document 3 describes an inkjet printing device that performs maintenance on an inkjet head by spraying cleaning liquid from a spray nozzle toward the nozzle surface to apply the cleaning liquid to the nozzle surface, and then pressing a fiber cloth against the nozzle surface to absorb the cleaning liquid. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-195934 [Patent Document 2] European Patent Application Publication No. 2738004A1 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-003491 Summary of the Invention [Problem to be solved by the invention]

[0007] However, wiping the nozzle surface too forcefully may damage the water-repellent film formed on the nozzle surface, while wiping the nozzle surface too lightly to avoid damaging the water-repellent film may not adequately remove ink mist and other particles adhering to the nozzle surface.

[0008] Patent Document 1 describes the magnitude of the force per unit length as the pressing force of the absorbing member against the nozzle face. Similarly, Patent Document 2 describes the magnitude of the force as the pressing force of the absorbing member against the nozzle face. However, the susceptibility of the nozzle face to damage varies depending on the type of absorbent used to wipe the nozzle face. For example, even when a specified pressing force is applied, there is a concern that the nozzle face may be damaged if an absorbing member that is prone to damaging the nozzle face is used.

[0009] Patent Document 3 does not describe the characteristics of the fiber cloth used to wipe the nozzle surface. When absorbing cleaning liquid applied to the nozzle surface, the characteristics of absorbing cleaning liquid vary depending on the type of fiber cloth, and the susceptibility to scratching the nozzle surface also varies depending on the type of fiber cloth. The invention described in Patent Document 3 has difficulty achieving both good absorption of cleaning liquid and prevention of scratching of the nozzle surface.

[0010] The present invention has been made in consideration of these circumstances, and aims to provide a head maintenance system, a printing system, and a head maintenance method that can achieve desirable cleaning of the nozzle surface and prevent damage to the nozzle surface. [Means for solving the problem]

[0011] The head maintenance system according to the present disclosure comprises a wiping device having a wiping sheet that wipes the nozzle surface of an inkjet head, a relative movement device that moves the inkjet head and the wiping sheet relative to each other, and a pressing device that presses the wiping sheet against the nozzle surface, wherein the wiping device is a head maintenance system having a wiping sheet whose compression linearity value measured using a compression tester is in the range of 0.3 or more and less than 0.6.

[0012] In the head maintenance system according to the present disclosure, the wiping sheet used to wipe the nozzle surface has a compression linearity value measured using a compression tester in the range of 0.3 to less than 0.6, thereby achieving favorable cleaning of the nozzle surface and suppressing damage to the nozzle surface when wiping it.

[0013] The nozzle surface of the inkjet head may include a configuration in which a water-repellent film that is liquid-repellent to ink is formed.

[0014] The wiping sheet is made of ink-absorbent paper, cloth, or the like.

[0015] In another aspect of the head maintenance system, the wiping device is provided with a wiping sheet that satisfies dT / T0≦−1.1×LC+0.7, where T0 is the uncompressed thickness when a specified pressure is not applied, dT is the compressed thickness when a specified pressure is applied, and LC is the compression linearity.

[0016] According to this aspect, it is possible to achieve both the ability to wipe the nozzle surface and the prevention of scratches on the nozzle surface.

[0017] In a head maintenance system according to another aspect, the wiping device includes a wiping sheet in which the uncompressed thickness T0, the compressed thickness dT, and the compression linearity LC satisfy 0.4≦dT / T0≦−1.1×LC+0.7.

[0018] According to this aspect, the precision of the mechanical mechanism for pressing the wiping sheet against the nozzle surface can be relaxed.

[0019] In a head maintenance system according to another aspect, the wiping device includes a wiping sheet in which the uncompressed thickness T0, the compressed thickness dT, and the compression linearity LC satisfy -1.2×LC+0.7≦dT / T0≦-1.1×LC+0.7.

[0020] According to this aspect, it is possible to achieve more preferable wiping performance.

[0021] A head maintenance system according to another aspect includes a cleaning liquid applying device that applies cleaning liquid to at least one of the nozzle surface and the wiping sheet.

[0022] According to this aspect, ink adhering to the nozzle surface can be dissolved using the cleaning liquid.

[0023] A head maintenance system according to another embodiment includes one or more processors, and the processor defines the compression work of the wiping sheet measured using a compression tester as WC, and when the compression work WC is equal to or greater than 0.03 gram-force per centimeter and equal to or less than 0.59 gram-force per centimeter, controls the cleaning liquid application device so that the amount of cleaning liquid applied from the cleaning liquid application device is in the range of equal to or greater than 0.41 × WC + 0.01 milliliters per square centimeter and equal to or less than 0.76 × WC + 0.02 milliliters per square centimeter.

[0024] According to this aspect, it is possible to prevent ejection abnormalities in the inkjet head caused by an excess or deficiency of the cleaning liquid.

[0025] A head maintenance system according to another aspect includes a cleaning liquid wiping device that uses a dry wiping sheet to wipe off cleaning liquid adhering to the nozzle surface.

[0026] According to this aspect, it is possible to prevent problems from occurring in the inkjet head due to cleaning liquid remaining on the nozzle surface.

[0027] In a head maintenance system according to another aspect, the pressing device applies a pressure of 5 kilopascals or more and 20 kilopascals or less to the nozzle surface.

[0028] According to this aspect, when wiping the nozzle surface, a pressure within an appropriate range is applied to the nozzle surface.

[0029] A printing system according to the present disclosure includes an inkjet head and a maintenance device for the inkjet head. The maintenance device includes a wiping sheet that wipes the nozzle surface of the inkjet head, a relative movement device that moves the inkjet head and the wiping sheet relative to each other, and a pressing device that presses the wiping sheet against the nozzle surface. The wiping sheet has a compression linearity value in the range of 0.3 or more and less than 0.6 when measured with a compression tester.

[0030] The printing system according to the present disclosure can achieve the same effects as the head maintenance system according to the present disclosure. The components of the head maintenance system according to other aspects can be applied to the printing system according to other aspects.

[0031] In a printing system according to another aspect, the inkjet head has a water-repellent film formed on the nozzle surface, which is water-repellent to the ink ejected from the inkjet head.

[0032] According to this aspect, it is possible to suppress adhesion of ink to the nozzle surface of the inkjet head.

[0033] The head maintenance method according to the present disclosure is a head maintenance method in which a wiping sheet for wiping the nozzle surface is pressed against the nozzle surface of an inkjet head, the inkjet head and the wiping sheet are moved relative to each other, and the nozzle surface is wiped using the wiping sheet, and the head maintenance method applies a wiping sheet whose compression linearity value, measured using a compression tester, is in the range of 0.3 or more and less than 0.6.

[0034] According to the head maintenance method of the present disclosure, it is possible to obtain the same effects as those of the head maintenance system of the present disclosure. The constituent elements of the head maintenance system of other aspects can be applied to the constituent elements of the head maintenance method of other aspects. [Effects of the Invention]

[0035] According to the present invention, the wiping sheet used to wipe the nozzle surface has a compression linearity value measured using a compression tester in the range of 0.3 to less than 0.6, thereby achieving favorable cleaning of the nozzle surface and suppressing damage to the nozzle surface when wiping it. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a diagram showing the overall configuration of a head maintenance system according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram showing the electrical configuration of the head maintenance system shown in FIG. [Figure 3] FIG. 3 is an explanatory diagram of the compression linearity of the web applied to the head maintenance system shown in FIG. [Figure 4] FIG. 4 is a graph showing compression linearity for each web. [Figure 5] FIG. 5 is a graph showing the results of the evaluation experiment. [Figure 6] FIG. 6 is a graph showing the results of an evaluation experiment on the change over time of the nozzle surface. [Figure 7] FIG. 7 is a graph showing the relationship between compression linearity and web push-in amount. [Figure 8] FIG. 8 is a graph showing the evaluation results of the compression work load of the web and the amount of applied cleaning liquid. [Figure 9] FIG. 9 is a diagram showing the overall configuration of a printing system according to an embodiment. [Figure 10] FIG. 10 is a front view showing an example of the configuration of a maintenance device applied to the printing system shown in FIG. [Figure 11]FIG. 11 is a plan view of the maintenance device shown in FIG. [Figure 12] FIG. 12 is a perspective view showing a schematic configuration of an inkjet head applied to the printing system shown in FIG. [Figure 13] FIG. 13 is a plan view showing a schematic configuration of the nozzle surface of the inkjet head shown in FIG. [Figure 14] FIG. 14 is an enlarged plan view of the nozzle surface of one head module, which is a part of the nozzle surface. [Figure 15] FIG. 15 is a functional block diagram showing the electrical configuration of the printing system shown in FIG. [Figure 16] FIG. 16 is a flowchart showing the steps of a head maintenance method according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0037] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In this specification, the same components are designated by the same reference numerals, and redundant explanations will be omitted where appropriate.

[0038] [Overall configuration of the head maintenance system] 1 is a diagram showing the overall configuration of a head maintenance system according to an embodiment of the present invention. The head maintenance system 1 shown in the drawing includes a head moving device 2, a cleaning device 3, and a cleaning liquid applying device 4.

[0039] The head moving device 2 supports the inkjet head 50 and moves the inkjet head 50 in the head movement direction. Fig. 1 illustrates an example of the configuration of the head moving device 2, which includes a ball screw 60, a carriage 62, and a head moving motor 64. The head moving device 2 described in the embodiment is an example of a component of a relative moving device.

[0040] The carriage 62 is movably attached to the ball screw 60. The inkjet head 50 is connected to the carriage 62. The rotation shaft of the head movement motor 64 is connected to the ball screw 60.

[0041] The ball screw 60 rotates in response to the driving of the head movement motor 64, and the carriage 62 moves along the ball screw 60 in response to the rotation of the ball screw 60. As a result, the inkjet head 50 connected to the carriage 62 can move along the head movement direction when wiping the nozzle surface 52.

[0042] 1 moves from right to left in the figure when wiping the nozzle surface 52. The arrow line shown near the inkjet head 50 indicates the direction of head movement when wiping the nozzle surface 52.

[0043] 1 shows a line-type inkjet head 50. The movement direction of the inkjet head 50 shown in the figure is along the longitudinal direction of the inkjet head 50. Note that the head maintenance system 1 may also be applied to a serial-type inkjet head.

[0044] The cleaning device 3 brings the web 10 into contact with the nozzle surface 52 of the inkjet head 50 moving in the head movement direction, and presses the web 10 against the nozzle surface 52 to wipe the nozzle surface 52 .

[0045] The cleaning device 3 includes a web 10, a case 12, a supply shaft 14, a winding shaft 16, a pressure roller 18, a front guide section 20, a rear guide section 22, and a feed roller 24. The cleaning device 3 also includes a supply shaft rotation drive motor 32, a winding shaft rotation drive motor 34, a feed roller rotation drive motor 36, and a control circuit 38. The cleaning device 3 described in the embodiment is an example of a wiping device.

[0046] An absorbent strip-shaped sheet material is used as the web 10. The web 10 can be manufactured using fiber cloth, woven fabric, knitted fabric, or nonwoven fabric. The web 10 can be made of polyester, nylon, or cellulose-based fiber.

[0047] The fibers applied to the web 10 may have a diameter smaller than the diameter of the nozzles provided in the inkjet head 50. Examples of the diameter of the fibers applied to the web 10 include a range of 1.0 micrometers or more and 5.0 micrometers or less.

[0048] The width of the web 10 corresponds to the width in the short-side direction of the nozzle surface 52 of the inkjet head 50. For example, the width of the web 10 may be the same as the width of the nozzle surface 52 in the short-side direction. Alternatively, the width of the web 10 may be larger than the width of the nozzle surface 52 in the short-side direction.

[0049] The term "same width" does not necessarily mean that they are exactly the same, but may include a tolerance range within which they can be considered to be substantially the same width. The width in the short direction of the nozzle surface 52 of the inkjet head 50 is the width in the direction perpendicular to the longitudinal direction of the inkjet head 50, which is the direction of movement of the inkjet head 50 on the nozzle surface 52. The width of the web 10 is not limited to the above example. The web 10 described in the embodiment is an example of a wiping sheet.

[0050] The case 12 is a housing that houses the web 10. The case 12 is provided with a bearing that supports the supply shaft 14 and a bearing that supports the winding shaft 16, etc. The bearings provided in the case 12 are not shown in the drawing.

[0051] The supply shaft 14 is rotatably supported by a bearing provided in the case 12. A reel is detachably attached to the supply shaft 14. The web 10 is wound around the reel in a roll and attached to the supply shaft 14. The supply shaft 14 is connected to the rotating shaft of a supply shaft rotation drive motor 32 and rotates in response to the drive of the supply shaft rotation drive motor 32.

[0052] The winding shaft 16 is rotatably supported by a bearing provided in the case 12. A reel is detachably attached to the winding shaft 16. The winding shaft 16 is connected to the rotating shaft of a winding shaft rotation drive motor 34, and rotates in response to the drive of the winding shaft rotation drive motor 34. The web 10 is wound into a roll on the reel attached to the winding shaft 16. The reels provided on the supply shaft 14 and the winding shaft 16 are not shown in the drawings.

[0053] The pressure roller 18 is a roller that brings the web 10 into contact with the nozzle surface 52 and presses the nozzle surface 52. The pressure roller 18 is supported by a shaft support member provided in the case 12 so as to be rotatable and movable up and down. The shaft support member is not shown in the drawing.

[0054] 1, the pressure roller 18 is supported by a shaft support member in a state where it is biased in a direction to press the nozzle surface 52. A spring 56 biases the pressure roller 18 upward.

[0055] A travel path is set for the web 10 so that the web 10 is wrapped around the upper peripheral surface of the pressure roller 18. The pressure roller 18 causes the web 10 to come into contact with the nozzle surface 52 of the inkjet head 50 and press against the nozzle surface 52. In other words, the pressure roller 18 and the spring 56 function as a pressing device that applies pressure to the web 10.

[0056] The front guide section 20 guides the running of the web 10 between the supply shaft 14 and the pressure roller 18. The front guide section 20 includes guide rollers 20A, 20B, and 20C as guide members.

[0057] The guide rollers 20A, 20B, and 20C are each disposed at a predetermined position in the case 12. The guide rollers 20A, 20B, and 20C are rotatably supported by bearings provided in the case 12.

[0058] The web 10 is wound around guide rollers 20A, 20B, and 20C, and runs between the supply shaft 14 and the pressure roller 18. Bearings that support the guide roller 20A and the like are not shown. An arrow near the web 10 indicates the running direction of the web 10. The running direction of the web 10 is opposite to the movement direction of the inkjet head 50 in the region where the nozzle surface 52 and the web 10 contact each other.

[0059] The rear guide section 22 guides the travel of the web 10 at a position between the pressure roller 18 and the feed roller 24. The rear guide section 22 includes guide rollers 22A and 22B as guide members. The guide rollers 22A and 22B are each disposed at a specified position in the case 12. The guide rollers 22A and 22B are rotatably supported by bearings provided in the case 12. Note that the bearings supporting the guide rollers 22A and the like are not shown in the drawing.

[0060] The number and positions of the guide rollers provided in the front guide section 20 and the rear guide section 22 are adjusted appropriately depending on the positions of the supply shaft 14, winding shaft 16, pressure roller 18, etc.

[0061] The feed roller 24 feeds the web 10. The feed roller 24 is rotatably supported by a bearing provided in the case 12. The feed roller 24 is connected to the rotary shaft of the feed roller rotation drive motor 36, and rotates in response to the drive of the feed roller rotation drive motor 36. This feeds the web 10 wound around the feed roller 24. A nip roller is disposed opposite the feed roller 24. The nip roller is not shown in the drawing.

[0062] The supply shaft rotation drive motor 32 is a power source that rotates the supply shaft 14. The supply shaft rotation drive motor 32 may be attached to the case 12 or may be disposed outside the case 12.

[0063] The supply shaft 14 rotates in response to the drive of the supply shaft rotation drive motor 32. Furthermore, the rotation of the supply shaft 14 is stopped in response to the stopping of the drive of the supply shaft rotation drive motor 32. This stops the unwinding of the web 10. In other words, the supply shaft rotation drive motor 32 has a function of braking the web 10, and brakes the running of the web 10 on the upstream side of the pressure roller 18. The arrow line shown on the web 10 wound around the supply shaft 14 indicates the rotation direction of the supply shaft 14.

[0064] The winding shaft rotation drive motor 34 is a power source that rotates the winding shaft 16. The winding shaft rotation drive motor 34 may be attached to the case 12 or may be disposed outside the case 12. The arrow line shown on the web 10 wound around the winding shaft 16 indicates the rotation direction of the winding shaft 16.

[0065] Feed roller rotation drive motor 36 is a power source that rotates feed roller 24. Feed roller rotation drive motor 36 may be attached to case 12 or may be disposed outside case 12. The arrow line illustrated on feed roller 24 indicates the rotation direction of feed roller 24.

[0066] The control circuit 38 controls the driving of the supply shaft rotation drive motor 32, the take-up shaft rotation drive motor 34, and the feed roller rotation drive motor 36, and controls the running of the web 10. Note that the mechanisms for running the web 10, such as the supply shaft 14, the supply shaft rotation drive motor 32, and the pressure roller 18 described in the embodiment, are examples of components of a head moving device that moves the inkjet head and the wiping sheet relative to each other.

[0067] The head maintenance system 1 includes a cleaning liquid deposition device 4. The cleaning liquid deposition device 4 includes a cleaning liquid tank 70, a cleaning liquid flow path 72, a cleaning liquid pump 74, and a cleaning liquid spray nozzle. The cleaning liquid spray nozzle is not shown.

[0068] The cleaning liquid application device 4 drives the cleaning liquid pump 74 to draw up the cleaning liquid from the cleaning liquid tank 70, and applies the cleaning liquid to the web 10 via the cleaning liquid flow path 72 and the cleaning liquid spray nozzle. In the present embodiment, an example has been given in which the cleaning liquid is applied to the nozzle surface 52 via the web 10, but the cleaning liquid may also be applied directly from the cleaning liquid application device 4 to the nozzle surface 52.

[0069] [Electrical configuration of the head maintenance system] Fig. 2 is a functional block diagram showing the electrical configuration of the head maintenance system shown in Fig. 1. The head maintenance system 1 includes a processor 100 and a memory 102. The processor 100 executes various programs stored in the memory 102 to realize various functions in the head maintenance system 1. The term "program" is synonymous with the term "software."

[0070] The head maintenance system 1 includes a communication interface 104. The communication interface 104 performs data communication with an external device under the control of the processor 100. The communication interface 104 may use various standards such as USB (Universal Serial Bus). The communication form of the communication interface 104 may be either wired communication or wireless communication.

[0071] The head maintenance system 1 includes an operation device 106. The operation device 106 may be a keyboard, a mouse, or the like. A user can input various pieces of information using the operation device 106. The operation device 106 transmits signals representing the various pieces of information input by the user to the processor 100. The processor 100 realizes various functions of the head maintenance system 1 based on the acquired signals.

[0072] The head maintenance system 1 includes a display device 108. The display device 108 displays various types of information in the head maintenance system 1. A touch panel system may be applied to the display device 108, and the operation device 106 and the display device 108 may be integrated into one unit.

[0073] The processor 100 includes a system control unit 120, a travel control unit 122, a head movement control unit 124, and a cleaning liquid application control unit 126. The units included in the processor 100 correspond to various functions of the head maintenance system 1.

[0074] The system control unit 120 performs overall control of each unit included in the head maintenance system 1. That is, the system control unit 120 transmits command signals to the various control units included in the processor 100. The various control units control each unit based on the received command signals.

[0075] The travel control unit 122 operates the web travel device 128 based on a command signal sent from the system control unit 120, and controls the travel of the web 10. The web travel device 128 shown in Fig. 2 includes the front guide unit 20, rear guide unit 22, feed roller 24, supply shaft rotation drive motor 32, take-up shaft rotation drive motor 34, and feed roller rotation drive motor 36 provided in the cleaning device 3 shown in Fig. 1. The web travel device 128 may also include a pressure roller 18.

[0076] The head movement control unit 124 operates the head moving device 2 based on a command signal sent from the system control unit 120, and controls the movement of the inkjet head 50. The head movement control unit 124 includes the control circuit 38 shown in FIG.

[0077] The cleaning liquid deposition control unit 126 operates the cleaning liquid deposition device 4 based on a command signal sent from the system control unit 120, and performs cleaning liquid deposition control, such as controlling the amount of cleaning liquid deposited per unit area on the nozzle surface.

[0078] The memory 102 includes a program memory 140, a parameter memory 142, and a data memory 144. The program memory 140 stores instructions that constitute various programs executed by the processor 100. The various programs correspond to various functions of the head maintenance system 1.

[0079] Various parameters corresponding to various programs are stored in parameter memory 142. When executing various programs, processor 100 reads parameters to be applied to the programs from parameter memory 142 and executes the programs by applying the parameters.

[0080] The data memory 144 stores various data applied to the head maintenance system 1. The memory 102 includes an arithmetic area used when the processor 100 executes various calculations.

[0081] The memory 102 may be implemented using semiconductor elements such as a read-only memory (ROM) and a random access memory (RAM). The memory 102 may also be implemented using a magnetic storage medium such as a hard disk. The memory 102 may also include multiple types of storage elements.

[0082] Examples of the hardware structure of the processor 100 include a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a PLD (Programmable Logic Device), and an ASIC (Application Specific Integrated Circuit). A CPU is a general-purpose processor that executes programs and functions as various functional units. A GPU is a processor specialized for image processing.

[0083] A PLD is a processor whose electrical circuit configuration can be changed after the device is manufactured. An example of a PLD is an FPGA (Field Programmable Gate Array). An ASIC is a processor with dedicated electrical circuitry designed specifically to perform a specific task.

[0084] A processing unit may be configured with one of these various processors, or may be configured with two or more processors of the same or different types. Examples of combinations of various processors include a combination of one or more FPGAs and one or more CPUs, and a combination of one or more FPGAs and one or more GPUs. Another example of a combination of various processors is a combination of one or more CPUs and one or more GPUs.

[0085] A single processor may be used to configure multiple functional units. An example of using a single processor to configure multiple functional units is a configuration in which a single processor is configured by applying a combination of one or more CPUs and software, such as an SoC (System On Chip), which is typified by a computer such as a client or server, and this processor operates as multiple functional units.

[0086] Another example of using one processor to configure multiple functional units is to use a processor that uses one IC chip to realize the functions of an entire system including multiple functional units. Note that IC is an abbreviation for Integrated Circuit.

[0087] In this way, the various functional units are configured as hardware structures using one or more of the various processors described above.More specifically, the hardware structures of the various processors described above are electric circuits (circuitry) that combine circuit elements such as semiconductor elements.

[0088] [Detailed explanation of wiping the nozzle surface] In the head maintenance system 1 according to the embodiment, the physical properties of the web 10 that wipes the nozzle surface 52 and the pressure with which the web 10 presses against the nozzle surface 52 are specified, and cleaning is performed by bringing the web 10 into contact with the nozzle surface 52. In addition, the head maintenance system 1 specifies the amount of cleaning liquid to be applied per unit area of ​​the nozzle surface, and performs non-contact cleaning of the nozzle surface using a cleaning liquid film formed on the nozzle surface 52.

[0089] This allows for the maintenance of favorable wiping performance when wiping the nozzle surface, and also for the realization of wiping of the nozzle surface 52 that suppresses damage to the nozzle surface 52. Note that favorable wiping performance when wiping the nozzle surface means wiping performance of the nozzle surface that suppresses the occurrence of ejection abnormalities in the inkjet head 50 due to deposits on the nozzle surface 52. Furthermore, if a water-repellent film is formed on the nozzle surface 52, scratches on the nozzle surface 52 are synonymous with scratches on the water-repellent film.

[0090] [Web Compression Linearity] Compression linearity LC measured using a compression tester is defined as a physical property of the web 10. An example of the compression tester is the compression tester KES-FB3-A manufactured by Kato Tech Co., Ltd.

[0091] The compression linearity LC is an index representing the softness of the web 10. A web 10 with a relatively small compression linearity LC is relatively soft, and dried ink mist adhering to the nozzle surface 52 tends to be difficult to remove.

[0092] On the other hand, a web 10 with a relatively large compression linearity LC is relatively hard and tends to easily scratch the nozzle surface 52. Therefore, in the head maintenance system 1 according to this embodiment, the value of the compression linearity LC of the web 10 is specified to be in the range of 0.3 to 0.6. This enables wiping of the nozzle surface 52 that maintains favorable wiping performance of the nozzle surface 52 while suppressing scratches on the nozzle surface 52.

[0093] Fig. 3 is an explanatory diagram of the compression linearity of the web applied to the head maintenance system shown in Fig. 1. Fig. 3 shows a graph showing the relationship between the amount of depression of the web 10 and the load per unit area applied to the web 10.

[0094] 3 represents the trajectory of the amount of depression of the web 10 when the load per unit area applied to the web 10 is increased from the minimum load value to the maximum load value. Curve 182 represents the trajectory of the amount of depression of the web 10 when the load per unit area applied to the web 10 is decreased from the maximum load value to the minimum load value.

[0095] The compression linearity LC is calculated by adding the area of ​​the area surrounded by curve 180 and curve 182 to the area of ​​the area surrounded by curve 182, line BC, and line AC, and dividing the sum by the area of ​​the area surrounded by line AB, line BC, and line AC.

[0096] [Evaluation of compression linearity] An evaluation experiment was conducted to verify the compressed linear LC applied to the web 10. The evaluation items in the evaluation experiment were the wiping performance of the nozzle surface 52 and damage to the nozzle surface 52. The wiping performance of the nozzle surface 52 was evaluated from the viewpoint of maintaining the ejection performance and removing solidified ink. The conditions, method, and results of the evaluation experiment are as follows.

[0097] <Conditions for evaluation experiments> The inkjet head 50 is a line-type inkjet head using a piezoelectric ejection method. Piezoelectric inkjet heads have a piezoelectric element as an ejection force generating element, and eject ink from nozzle openings by utilizing the flexural deformation of a thick element. The inkjet head 50 has a structure in which multiple nozzle openings are arranged in a matrix. Each of the multiple nozzle openings is connected to a liquid chamber equipped with a piezoelectric element.

[0098] Seven types of webs having different values ​​of compression linearity LC were applied to the web 10. For each of the seven types of webs, three webs, web N1, web N2 and web N3, were applied to the web 10.

[0099] Figure 4 is a graph showing the compression linearity for each web. Three webs each, web 191 to web 197, were prepared, and the compression linearity LC value was calculated by changing the upper limit load. Here, the term "web" without a reference symbol refers to any one of web 10 and webs 191 to 197 shown in Figure 1, or to web 10 and webs 191 to 197 collectively.

[0100] The upper limit loads applied to webs 191, 192, and 193 were 100 gf, 200 gf, 300 gf, and 400 gf, respectively. The upper limit load applied to webs 194, 195, 196, and 197 was 100 gf. The values ​​shown in the graph are the average values ​​of the compression linearity LC for the three webs for each upper limit load.

[0101] The average value of the compression linearity LC of web 191 is in the range of 0.46 to 0.58, the average value of the compression linearity LC of web 192 is in the range of 0.36 to 0.40, and the average value of the compression linearity LC of web 193 is in the range of 0.33 to 0.44.

[0102] Meanwhile, the average value of the compression linearity LC of web 194 is 0.60, the average value of the compression linearity LC of web 195 is 0.71, the average value of the compression linearity LC of web 196 is 0.27, and the average value of the compression linearity LC of web 197 is 0.28.

[0103] <Evaluation experiment method> 10,000 dummy jets are performed from each of all the nozzles of the inkjet head 50 to deposit ink onto the nozzle surface 52 of the inkjet head 50.

[0104] The web to be evaluated is pressed against the nozzle surface 52. The pressure applied to press the nozzle surface 52 is 16 kilopascals. The web is run, and the inkjet head 50 is moved, using the web to wipe the nozzle surface 52. The inkjet head 50 is moved at a number of speeds ranging from 8 millimeters per second to 80 millimeters per second. The web is run at a speed of 3.2 millimeters per second. Note that the term "speed" can also mean a speed expressed using an absolute value of the speed.

[0105] It has been confirmed that similar results can be obtained within the above-mentioned range of moving speed of the inkjet head 50. Figure 5 shows the evaluation results when the moving speed of the inkjet head 50 is 40 millimeters per second.

[0106] Immediately after wiping of the nozzle surface 52 is completed, measurement of the deflection of the ejection of each nozzle is performed and confirmation of removal of the stuck ink on the nozzle surface 52 is carried out. Sticky ink is hardened or semi-hardened ink, and refers to ink that does not fall naturally from the nozzle surface 52.

[0107] Furthermore, immediately after the first wiping of the nozzle surface 52 and immediately after the final wiping of the nozzle surface 52, the nozzle surface 52 is checked for damage. A known method is used to measure the deflection of the ejection. Visual inspection is used to check for removal of solidified ink on the nozzle surface 52 and for damage to the nozzle surface 52. Visual inspection here includes observing the nozzle surface 52 by enlarging it using a microscope or the like.

[0108] One set of processing consists of the dummy jet, the wiping of the nozzle surface 52, and the evaluation immediately after wiping the nozzle surface 52, and one set of processing is performed 1,000 times. The evaluation immediately after wiping the nozzle surface 52 covers all nozzles provided in the inkjet head 50.

[0109] <Results of evaluation experiment> Figure 5 is a graph showing the results of the evaluation experiment. In the evaluation of deflected ejection, ++ indicates that the number of nozzles where deflected ejection beyond the specified limit occurred is 0, meaning that deflected ejection did not occur. In the evaluation of deflected ejection, + indicates that the number of nozzles where deflected ejection beyond the specified limit occurred is 1. In the evaluation of deflected ejection, - indicates that the number of nozzles where deflected ejection beyond the specified limit occurred is 2 or more. The standard for determining deflected ejection is 70 percent of the distance between dots corresponding to the printing resolution.

[0110] In the evaluation of fixed ink removal, ++ indicates that the diameter of the fixed ink adhering to the nozzle surface 52 is 25 percent or less of the diameter of the smallest size dot. In the evaluation of fixed ink removal, + indicates that the diameter of the fixed ink adhering to the nozzle surface 52 is more than 25 percent but not more than 50 percent of the diameter of the smallest size dot.

[0111] In the evaluation of solidified ink removal, a "-" indicates that the diameter of the solidified ink adhering to the nozzle surface 52 exceeds 50 percent of the diameter of the smallest dot. Note that if there are multiple solidified inks, the size of the solidified ink may be a representative value of the multiple solidified inks. The representative value may be the maximum value, average value, or the like.

[0112] In the evaluation of scratches on the nozzle surface, ++ indicates that no scratches were visible around each nozzle. In the evaluation of scratches on the nozzle surface, - indicates that scratches were visible around one or more nozzles. The periphery of the nozzle was defined as the area from the edge of the nozzle opening to a distance corresponding to 10 percent of the diameter of the nozzle opening.

[0113] For webs 196 and 197 with a compression linearity LC value of less than 0.33, the nozzle surface damage evaluation was ++, but the ejection deflection evaluation and the solidified ink removal evaluation were -. For webs 196 and 197 with a compression linearity LC value of less than 0.33, it is difficult to obtain the required wiping performance of nozzle surface 52.

[0114] Compression linearity LC value is 0.33 or more and 0.44 less thanFor webs 192 and 193 having a value of compression linearity LC of 0.33 or more and less than 0.44, the webs 192 and 193 are able to ensure the wiping performance of the nozzle surface 52 while suppressing scratches on the nozzle surface.

[0115] For the web 191 with a compression linearity LC value of 0.44 or more and less than 0.60, the evaluation of ejection deflection is ++, the evaluation of solidified ink removal is +, and the evaluation of nozzle surface damage is ++. Top 0 A web 191 with a diameter of less than 0.60 can ensure wiping performance of the nozzle surface 52 while preventing scratches on the nozzle surface.

[0116] Webs 194 and 195 with a compression linearity LC value of 0.60 or greater are rated as + for ejection deflection and ++ for solidified ink removal, but are rated as - for nozzle surface damage. For webs 194 and 195 with a compression linearity LC value of less than 0.60, it is difficult to prevent nozzle surface damage.

[0117] That is, the value of the compression linearity LC of the web 10 that ensures the wiping performance of the nozzle surface 52 and suppresses scratches on the nozzle surface is in the range of 0.33 or more and less than 0.60. Here, taking into consideration calculation errors when deriving the compression linearity LC, the value of the compression linearity LC can be set to the range of 0.3 or more and less than 0.60 by rounding the lower limit value of the compression linearity LC to one decimal place.

[0118] [Evaluation of changes over time on the nozzle surface] An evaluation experiment was conducted to verify the deterioration over time of the nozzle surface 52. The deterioration over time of the nozzle surface 52 refers to the change in the ejection characteristics of the inkjet head 50 and the presence or absence of scratches on the nozzle surface 52 when wiping processes are performed 3,000 times or more. The conditions for the evaluation experiment of the deterioration over time of the nozzle surface were the same as those for the evaluation experiment of the compressed linear LC described above.

[0119] Webs 191, 192, and 193, whose compression linearity LC value is in the range of 0.3 or more and less than 0.60, are the evaluation targets. Of webs 191, 192, and 193, web 191, which has the highest compression linearity and is most severe in terms of the change over time of the nozzle surface 52, was used in the evaluation experiment. The evaluation of the change over time of the nozzle surface is as follows: fruit The experimental method and results of the evaluation experiment are shown.

[0120] <Evaluation experiment method> 10,000 dummy jets are performed from each of all the nozzles of the inkjet head 50 to deposit ink onto the nozzle surface 52 of the inkjet head 50.

[0121] The web 10 is pressed against the nozzle surface 52. The web 10 is run, the inkjet head 50 is moved, and the web 10 is used to wipe the nozzle surface 52. Pressures of 5 kilopascals and 20 kilopascals are applied when pressing the web 10 against the nozzle surface 52. The moving speed of the inkjet head 50 is 40 millimeters per second. The running speed of the web 10 is 3.2 millimeters per second.

[0122] The dummy jet and the wiping of the nozzle surface 52 are counted as one set of processes, and one set of processes is performed 6,000 times. An evaluation of the change in the landing position is performed every 1,000 processes of one set. The evaluation of the change in the landing position covers all nozzles equipped in the inkjet head 50.

[0123] The standard deviation σ of the landing position errors for all nozzles is calculated. The deterioration rate is calculated for each wiping count, with the deterioration rate being set at 50 percent when the value of σ deteriorates by 1.5 times as the number of wiping counts increases. Here, the deterioration rate represents the degree of deterioration in the ejection performance of the inkjet head 50.

[0124] <Results of evaluation experiment> Figure 6 is a graph showing the results of an experiment to evaluate the deterioration of the nozzle surface over time. The graph also shows a regression line that graphically represents the progression of the deterioration rate. The horizontal axis of the graph in this figure is the number of wipes. The vertical axis of the graph in this figure is the deterioration rate.

[0125] In the figure, line 200 shows the change in the deterioration rate with respect to the number of wipes when the pressure applied to the web is 20 kPa, and line 202 shows the change in the deterioration rate with respect to the number of wipes when the pressure applied to the web is 5 kPa.

[0126] The lines 200 and 202 indicate that the deterioration rate increases as the number of wipes increases. The lines 200 and 202 also indicate that the increase in the deterioration rate is accelerated when the pressure applied to the web is relatively large.

[0127] For example, when the pressure applied to the web, represented by the straight line 200, is 20 kilopascals or less, the deterioration rate can be kept to 80 percent or less when the nozzle face 52 is wiped 6,000 times or less.

[0128] Furthermore, when the pressure applied to the web, represented by the straight line 202, is 5 kilopascals or less, the deterioration rate when wiping the nozzle surface 52 6,000 times or less can be kept to 20 percent or less. This makes it possible to ensure the ejection performance of the inkjet head 50 even when wiping the nozzle surface 52 6,000 times or less.

[0129] [Evaluation of the effect of wiping strength on landing position] An evaluation experiment was conducted to verify the effect of wiping strength on the landing position. Wiping strength represents the degree of deformation of the web when it presses against the nozzle face 52. As an index value for wiping strength, dT / T0 is used, which represents the ratio of the web's pressing amount dT when an arbitrary pressure is applied to the web, to the web's thickness T0 when no pressure is applied.

[0130] The main viewpoint of the experiment to evaluate the effect of wiping strength on the landing position is to prevent damage to the nozzle surface 52. fruit The experimental method and results of the evaluation experiment are shown.

[0131] <Evaluation experiment method> For each of webs 191 and 192 shown in Figure 4, the web compression amount dT when the pressure applied to the web is 5 kilopascals is derived, and the index value dT / T0 is calculated. A plot corresponding to the index value dT / T0 for web 191 and a plot corresponding to the index value dT / T0 for web 192 are obtained. Linear interpolation is performed between the two points to derive a line representing the relationship between the index value dT / T0 and the compression linearity LC when the pressure applied to the web is 5 kilopascals.

[0132] Similarly, for each of webs 191 and 192, the web compression amount dT when the pressure applied to the web is 20 kilopascals is derived, and the index value dT / T0 is calculated. A plot corresponding to the index value dT / T0 for web 191 and a plot corresponding to the index value dT / T0 for web 192 are obtained. Linear interpolation is performed between the two points to derive a straight line representing the relationship between the index value dT / T0 and the compression linearity LC when the pressure applied to the web is 20 kilopascals.

[0133] Here, the amount of web depression dT may be derived by calculation using a function that represents the relationship between the pressure applied to the web and the amount of depression in the web, or by measurement using the web.

[0134] FIG. 7 is a graph showing the relationship between compression linearity and web indentation amount. The horizontal axis of the graph shown in this figure is compression linearity LC, and the vertical axis is index value dT / T0. Line 210 represents the case where the pressure applied to the web is 20 kilopascals. Line 21 2 represents the case where the pressure applied to the web is 5 kilopascals.

[0135] A line 210 including plots 211 and 213 is expressed as dT / T0 = -1.1 x LC + 0.7. A line 212 including plots 215 and 217 is expressed as dT / T0 = -1.2 x LC + 0.7. A line 214 represents dT / T0 = 0.04.

[0136] When the value of compression linearity LC is in the range of 0.30 or more and less than 0.60, if dT / T0 > -1.1 x LC + 0.7, it is difficult to prevent damage to the nozzle surface 52. On the other hand, when the value of compression linearity LC is in the range of 0.30 or more and less than 0.60, if dT / T0 ≦ -1.1 x LC + 0.7, it is possible to prevent damage to the nozzle surface 52. Furthermore, when the index value dT / T0 is -1. 2 ×LC+0.7≦dT / T≦-1. 1 In the case of ×LC+0.7, it is possible to further suppress damage to the nozzle surface 52.

[0137] Here, if the web thickness T0 when not pressed is 0.3 millimeters, and the index value dT / T0 is about 0.04, it becomes necessary to control the web pressing amount dT with an accuracy of about 0.01 millimeters. This makes it difficult to ensure the stability of the mechanism that supports the web 10 when wiping the nozzle surface 52. Therefore, the index value dT / T0 of the web 10 shown in FIG. 1 is preferably 0.04 or greater.

[0138] The web thickness T0 in the case of no pressure described in the embodiment is an example of the uncompressed thickness T0 in the case of no specified pressure being applied. The web compression amount dT in the case of pressing the web by applying any specified pressure described in the embodiment is an example of the compressed thickness dT in the case of applying a specified pressure.

[0139] [Web compression workload] 1, the compression work load WC measured using a compression tester is specified as a physical property of the web 10. The compression work load WC is an index value of the web 10, indicating that the larger the value, the more easily the web 10 is compressed.

[0140] The larger the value of the compression work load WC, the better the cleaning liquid absorption, and the larger the amount of cleaning liquid held by the web 10 per unit area when a specified amount of cleaning liquid is applied to the nozzle surface 52. In order for the specified amount of cleaning liquid to be held by the nozzle surface 52, the amount of cleaning liquid applied to the web 10 is adjusted according to the value of the compression work load WC of the web 10.

[0141] If less than the specified amount of cleaning liquid is retained on the nozzle surface 52, the situation will be similar to wiping the nozzle surface 52 with the dry web 10, which may damage the nozzle surface 52. There is also concern that the meniscus surface may be disturbed due to ink being drawn out of the nozzle openings.

[0142] On the other hand, if more than a specified amount of cleaning liquid is retained on the nozzle surface 52, there is a concern that ejection abnormalities may occur due to the cleaning liquid remaining on the nozzle surface 52 after the nozzle surface 52 has been wiped.

[0143] The compression work WC is calculated by adding the area of ​​the region surrounded by curve 180 and curve 182 shown in Figure 3 to the area of ​​the region surrounded by curve 182, line BC, and line AC. Specifically, the compression work WC can be calculated by multiplying the pressure applied to the web 10 by the pressing amount dT of the web 10. The unit of the compression work WC is gram-force per centimeter.

[0144] Below, an evaluation experiment is conducted to verify the compression work WC of the web 10 and the amount of cleaning liquid applied, with a view to evaluating the image quality in printing performed after wiping the nozzle surface 52. The amount of cleaning liquid applied is the volume per unit area, and its unit is milliliters per square centimeter.

[0145] [Evaluation of Web Compression Work and Amount of Cleaning Liquid Applied] The conditions for the evaluation experiment of the web compression work load and the amount of cleaning liquid applied are as follows.

[0146] <Conditions for evaluation experiments> The paper used was OK Topcoat+ (product name) manufactured by Oji Paper Co., Ltd., with a basis weight of 157 gsm and a size of 750 mm x 530 mm. Note that gsm is an abbreviation for grams per square meter. Other conditions for the evaluation experiment, such as the type of web, were the same as those for the compression linearity LC evaluation experiment.

[0147] <Evaluation experiment method> The printing sequence is as follows: The nozzle surface 52 is wiped. A pressure of 16 kilopascals is applied to the nozzle surface 52. Then, 10,000 dummy jets are performed on all nozzles to deposit ink on the nozzle surface 52. After the dummy jets are completed, the inkjet head 50 is deactivated. The inkjet head 50 is deactivated for one hour.

[0148] After the non-operating period of the inkjet head 50 has ended, the nozzle surface 52 is wiped. The wiping conditions are the same as those used before the dummy jet. After wiping the nozzle surface 52, 500 solid images are printed using a 4C100 percent printing condition.

[0149] Here, the 4C100 percent printing condition means that in the CMYK display, the coverage of C, the coverage of M, the coverage of Y, and the coverage of K are each 100 percent. C, M, Y, and K represent cyan, magenta, yellow, and black, respectively.

[0150] The printing sequence described above was performed on three types of webs with compression work WC values ​​of 0.03 gram-force per centimeter, 0.21 gram-force per centimeter, and 0.59 gram-force per centimeter. The amount of cleaning liquid applied was gradually changed within the range of 0 milliliters per square centimeter to 0.45 milliliters per square centimeter, and printing sequences were performed for each web with different compression work WC.

[0151] The printed solid image is visually inspected for the presence or absence of streaks. Note that visual inspection may include magnifying and observing the solid image using a microscope or the like.

[0152] <Results of evaluation experiment> If streaks are visible in one or less of the 500 solid images, the image is judged as good. On the other hand, if streaks are visible in two or more of the 500 solid images, the image is judged as bad.

[0153] Figure 8 is a graph showing the evaluation results of the web compression work load and the amount of cleaning liquid applied. The figure shows the relationship between the compression work load WC and the amount of cleaning liquid applied. The horizontal axis of the graph shown in the figure is the compression work load WC, and the vertical axis is the amount of cleaning liquid applied.

[0154] A straight line 220 is derived by linearly interpolating between three points: plot 223, plot 224, and plot 225. Plot 223 represents the upper limit of the amount of cleaning liquid applied when the value of compression work WC is 0.03 gram-force per centimeter.

[0155] Similarly, plot 224 represents the upper limit of the amount of cleaning liquid applied when the value of compression work WC is 0.21 gram-force per centimeter. Plot 225 represents the upper limit of the amount of cleaning liquid applied when the value of compression work WC is 0.59 gram-force per centimeter. When the amount of cleaning liquid applied is V, line 220 is expressed as V = 0.76 × WC + 0.02.

[0156] A straight line 222 is derived by linearly interpolating between three points: plot 226, plot 227, and plot 228. Plot 226 represents the lower limit of the amount of cleaning liquid applied when the value of compression work WC is 0.03 gram-force per centimeter.

[0157] Similarly, plot 227 represents the lower limit of the amount of cleaning liquid applied when the value of the compression work WC is 0.21 gram-force per centimeter. 8represents the lower limit of the amount of cleaning liquid applied when the value of the compression work WC is 0.59 gram-force per centimeter. Line 222 is expressed as V=0.41×WC+0.01.

[0158] That is, when a web having a compression work rate WC of 0.03 gram-force per centimeter or more and 0.59 gram-force per centimeter or less is used, the application rate V of cleaning liquid is in the range of 0.41 × WC + 0.01 milliliters per square centimeter or more and 0.76 × WC + 0.02 milliliters per square centimeter or less. This makes it possible to prevent ejection abnormalities in the inkjet head 50 caused by an excess or deficiency of cleaning liquid when wiping the nozzle surface 52 to which the cleaning liquid is applied.

[0159] [Functions and Effects of the Head Maintenance System According to the Embodiment] The head maintenance system 1 according to the embodiment can achieve the following effects.

[0160] [1] When wiping the nozzle surface 52 of the inkjet head 50, the web 10 is applied, the value of which compression linearity LC measured using a compression tester is 0.3 or more and less than 0.6. This makes it possible to perform wiping of the nozzle surface 52 while realizing wiping performance of the nozzle surface 52 and suppressing scratches on the nozzle surface 52.

[0161] [2] The pressure applied to press the web 10 against the nozzle surface 52 is in the range of 5 kPa to 20 kPa. This suppresses deterioration of the nozzle surface 52 over a long period in which the nozzle surface 52 is wiped approximately 6,000 times.

[0162] [3] The thickness of the web 10 when no pressure is applied is T0, and the amount of depression of the web 10 when a given pressure is applied to the web 10 is dT. dT / T0 is used as an index value of wiping strength. The value of the compression linearity LC of the web 10 is 0.3 or more and 0.6 or less. less thanIn this range, the wiping strength index value dT / T0 satisfies dT / T0≦−1.1×LC+0.7. This makes it possible to prevent the nozzle surface 52 from being damaged, even when wiping of the nozzle surface 52 is performed repeatedly.

[0163] [4] The index value dT / T0 of the wiping strength satisfies 0.04≦dT / T0≦−1.1×LC+0.7, thereby ensuring the stability of the mechanism that supports the web when wiping the nozzle surface 52.

[0164] [5] The index value dT / T0 of the wiping strength satisfies −1.2×LC+0.7≦dT / T0≦−1.1×LC+0.7, which significantly reduces the effect of preventing the nozzle surface 52 from being damaged.

[0165] [6] wash When wiping the nozzle surface 52 on which the cleaning liquid film is formed, the amount of cleaning liquid applied per unit area, V, satisfies 0.41×WC+0.01≦V≦0.76×WC+0.02 when the compression work WC of the web 10 is in the range of 0.03 gram-force per centimeter or more and 0.59 gram-force per centimeter or less. This makes it possible to suppress ejection abnormalities in the inkjet head 50 caused by an excess or deficiency of cleaning liquid.

[0166] [Example of application to printing systems] Next, an example of application of the head maintenance system 1 described using Figures 1 to 8 to a printing system will be described. The printing system 300 shown below prints color images using cyan, magenta, yellow, and black inks.

[0167] [Overall structure] Figure 9 is a diagram showing the overall configuration of a printing system according to an embodiment. The printing system 300 shown in the figure includes a paper feeder 302, a jetting device 304, a drying device 306, and a paper discharge device 308. The printing system 300 uses roll paper as the continuous sheet of paper 320, and performs continuous printing on the roll paper. The two-dot chain line in Figure 1 indicates the transport path of the paper 320.

[0168] The printing system 300 also includes a maintenance device that performs maintenance on the inkjet heads provided in the jetting device 304. The maintenance device is not shown in Figure 9. The maintenance device is shown in Figure 10 using the reference numeral 310.

[0169] The paper feeder 302 accommodates a feed roll 322 around which paper 320 is wound. The paper 320 sent out from the feed roll 322 is transported to the jetting device 304. The arrows shown on the paper feeder 302 indicate the transport direction of the paper 320.

[0170] In the present embodiment, the printing system 300 is exemplified as being applied to the continuous sheet of paper 320, but sheet-fed paper may also be applied to the printing system 300. In an aspect in which sheet-fed paper is applied, the paper feeder 302 includes a paper feed tray that stores the sheet-fed paper.

[0171] Jetting device 304 includes inkjet head 330C, inkjet head 330M, inkjet head 330Y, and inkjet head 330K. Jetting device 304 includes a print drum 332.

[0172] Inkjet head 330C, inkjet head 330M, inkjet head 330Y, and inkjet head 330K shown in FIG. 9 correspond to inkjet head 50 shown in FIG.

[0173] The inkjet head 330C, the inkjet head 330M, the inkjet head 330Y, and the inkjet head 330K eject cyan ink, magenta ink, yellow ink, and black ink, respectively.

[0174] Jetting device 304 prints a color image on paper 320 supported by suction on outer peripheral surface 332A of print drum 332 using inkjet head 330C, inkjet head 330M, inkjet head 330Y, and inkjet head 330K.

[0175] The jetting device 304 may include an inkjet head that ejects white ink. The inkjet head that ejects white ink is located downstream of the inkjet head 330K in the paper transport direction, and forms a base for a color image to be printed on the transparent paper 320.

[0176] The inkjet head that ejects white ink can be located downstream of the inkjet head 330K in the paper transport direction and upstream of the in-line sensor 334.

[0177] The jetting device 304 includes an in-line sensor 334. The in-line sensor 334 reads the image printed on the paper 320 and outputs the read data. The printing system 300 determines whether or not there is an ejection abnormality in the inkjet head 330 based on the read data.

[0178] 9 illustrates an example in which the print drum 332 is used to transport the paper 320, but the transport of the paper 320 is not limited to an example in which the print drum 332 is used. For example, an example in which a transport belt is used may also be used.

[0179] The drying device 306 includes a paper transport unit 340 and a drying unit 342. The paper transport unit 340 supports the paper 320 delivered from the print drum 332 and transports the paper 320.

[0180] 9 shows an example of a configuration of paper transport unit 340 that includes a transport belt. Paper transport unit 340 may also include a chain gripper or a nip roller. Paper transport unit 340 may also include a combination of multiple types of transport members, such as a combination of a transport belt and a chain gripper.

[0181] The drying unit 342 performs a drying process on the paper 320 transported by the paper transport unit 340. The paper transport unit 340 may be configured to blow out hot air or radiate heat. The paper transport unit 340 may use a combination of multiple types of methods.

[0182] The paper discharge device 308 accommodates a take-up roll 350 on which printed paper 320 is wound. The paper discharge device 308 may include a cutting device that cuts the paper 320 to a specified length and a stacking device that stacks the paper 320 cut to the specified length. The paper discharge device 308 may also include a stamping device that stamps any printed matter that is found to have a defect based on the inspection results of the printed matter.

[0183] [Maintenance device] Fig. 10 is a front view showing an example of the configuration of a maintenance device applied to the printing system shown in Fig. 9. Fig. 11 is a plan view of the maintenance device shown in Fig. 10.

[0184] The maintenance device 310 includes a head moving device 360, a cleaning device 380, and a capping device 390. The head moving device 360 ​​moves the inkjet head 330C, the inkjet head 330M, the inkjet head 330Y, and the inkjet head 330K all at once.

[0185] The head moving device 360 ​​includes a horizontal movement mechanism 362. The horizontal movement mechanism 362 includes a guide rail 364, a ball screw 366, a nut 368, a motor 370, and a pair of frames 372. The head moving device 360 ​​includes an elevation mechanism. The elevation mechanism raises and lowers the inkjet head 330C and other components together. The elevation mechanism is not shown in the figures.

[0186] The horizontal movement mechanism 362 reciprocates the inkjet heads 330C and other heads between the printing position and the capping position within a plane parallel to the horizontal plane along the horizontal direction. The printing position is directly above the print drum 332, and is the position of the inkjet heads 330C and other heads when printing on the paper 320. The capping position is directly above the cap device 390, and is the position of the inkjet heads 330C and other heads when capping.

[0187] The inkjet head 330C and other components are integrally supported by a frame 372. The frame 372 is connected to a nut 368. The motor 370 is operated to rotate the ball screw 366. The frame 372 connected to the nut 368 moves horizontally, and the inkjet head 330C and other components move horizontally in a plane parallel to the horizontal plane. A controllable motor, such as a stepping motor or servo motor, whose rotation and stopping can be controlled using a command signal, is used as the motor 370. The head moving device 360 ​​described in the embodiment is an example of a component of a relative moving device.

[0188] The cleaning device 380 includes a cyan head cleaning unit 382C, a magenta head cleaning unit 382M, a yellow head cleaning unit 382Y, and a black head cleaning unit 382K. Reference numeral 382 shown in Fig. 10 represents a generic term for the cyan head cleaning unit 382C, etc., or any one of these. Reference numeral 384 represents a generic term for a web 384C, etc., or any one of these.

[0189] The cyan head cleaning unit 382C uses a web 384C to wipe the nozzle surface 331C of the inkjet head 330C, and the magenta head cleaning unit 382M uses a web 384M to wipe the nozzle surface of the inkjet head 330M.

[0190] The yellow head cleaning unit 382Y uses a web 384Y to wipe the nozzle surface of the inkjet head 330Y, and the black head cleaning unit 382K uses a web 384K to wipe the nozzle surface of the inkjet head 330K.

[0191] The cleaning device 3 shown in FIG. 1 is applied to the cyan head cleaning unit 382C, the magenta head cleaning unit 382M, the yellow head cleaning unit 382Y, and the black head cleaning unit 382K.

[0192] 1 is applied to webs 384C, 384M, 384Y, and 384K shown in Fig. 10. The cleaning unit 382 described in the embodiment is an example of a component of the relative movement device. The web 384 described in the embodiment is an example of a wiping sheet.

[0193] The cap device 390 includes caps 392C, 392M, 392Y, and 392K. The cap 392C caps the inkjet head 330C. The caps 392M, 392Y, and 392K cap the inkjet head 330M, the inkjet head 330Y, and the inkjet head 330K, respectively.

[0194] The frame 372 and inkjet head 330C shown by dashed lines in FIG. 10 show the inkjet head 330C and the like in a state where they are capped with a cap 392C.

[0195] The maintenance device 310 is a cleaning liquid wiper that applies a dry web to wipe off the cleaning liquid from the nozzle surface 331. Tori The cleaning liquid wiping device may have a similar configuration to the cleaning unit 382. The maintenance device 310 described in the embodiment is an example of a head maintenance system. The dry web described in the embodiment is an example of a dry wiping sheet.

[0196] [Example of inkjet head configuration] Figure 12 is a perspective view showing a schematic configuration of an inkjet head applied to the printing system shown in Figure 9. The inkjet head 330C, inkjet head 330M, inkjet head 330Y, and inkjet head 330K shown in Figure 9 have the same configuration. In the following description, inkjet head 330C and the like will be collectively referred to as inkjet head 330.

[0197] The inkjet head 330 shown in Fig. 12 is a line-type inkjet head. A single bar-shaped inkjet head 330 is configured by connecting a plurality of head modules 400. The head modules 400 are attached to and integrated with a bar frame 402. The head modules 400 can be replaced individually.

[0198] Fig. 13 is a plan view showing a schematic configuration of the nozzle surface of the inkjet head shown in Fig. 12. The nozzle surface 331 of the inkjet head 330 has a generally rectangular shape overall, with a nozzle arrangement region 331A formed in the central portion in a direction perpendicular to the longitudinal direction. Nozzles, which are ejection ports for ejecting ink droplets, are provided in the nozzle arrangement region 331A.

[0199] Figure 14 is an enlarged plan view of the nozzle surface of one head module, which is a part of the nozzle surface. The direction indicated by the symbol X in Figure 14 is the longitudinal direction of the inkjet head 330. The X direction is called the head longitudinal direction. The head longitudinal direction corresponds to the main scanning direction.

[0200] The direction indicated by the symbol Y in FIG. 14 is the direction along the transport direction of the paper 320. The Y direction is called the paper transport direction. The paper transport direction corresponds to the sub-scanning direction. The X direction shown in FIG. 14 is the running direction of the web 10, and the Y direction shown in FIG. 14 is the width direction of the web 10.

[0201] A plurality of nozzle openings 410 are arranged in a matrix on the nozzle surface 331 of the inkjet head 330. For example, on the nozzle surface 331, the nozzle openings 410 are arranged at a constant pitch along a straight line X1 that is inclined at an angle γ with respect to the X direction, and the nozzle openings 410 are arranged at a constant pitch along a straight line Y1 that is inclined at an angle α with respect to the Y direction.

[0202] By arranging the nozzle openings 410 in this manner, the effective interval between the nozzle openings 410 projected to be aligned in the main scanning direction can be narrowed, and the nozzle openings 410 can be arranged at a high density. In this case, the effective arrangement direction of the nozzle openings 410 is the X direction. In other words, the nozzle openings 410 are arranged substantially along the longitudinal direction of the inkjet head 330.

[0203] A water-repellent film that is water-repellent to ink is formed on the nozzle arrangement region 331A of the nozzle surface 331. This prevents dirt from adhering to the periphery of the nozzle openings 410. A fluororesin film can be used as the water-repellent film.

[0204] Although the present embodiment illustrates an inkjet head 330 including a plurality of head modules 400, the inkjet head 330 may include one or more head modules 400. Furthermore, the arrangement of the plurality of head modules 400 is not limited to a single row, and a zigzag arrangement or the like may also be used.

[0205] The inkjet head 330 may be configured to use a piezoelectric method in which the deflection of a piezoelectric element is used to eject liquid contained in a liquid chamber provided with the piezoelectric element from the nozzle opening 410. The inkjet head 330 may also be configured to use a thermal method in which ink is heated using a heater and film boiling of the ink is utilized.

[0206] [Electrical configuration of the printing system] Fig. 15 is a functional block diagram showing the electrical configuration of the printing system shown in Fig. 9. The printing system 300 includes one or more processors 420 and one or more memories 422. The processor 420 reads out various programs stored in the memory 422 and executes the read out programs to realize various functions of the printing system 300. In other words, various control units included in the processor 420 correspond to various functions of the printing system 300.

[0207] The printing system 300 includes a communication interface 424. The communication interface 424 acquires data transmitted from an external device. The communication interface 424 also transmits data to the external device. Examples of the external device include computers such as a server device and a terminal device. Another example of the external device is a storage device such as a storage device.

[0208] The communication interface 424 may use various communication standards, such as USB (Universal Serial Bus). The printing system 300 may include multiple communication interfaces 424 that correspond to multiple communication standards. The communication form of the communication interface 424 may be either wired communication or wireless communication.

[0209] The printing system 300 includes an operation device 426 and a display device 428. The operation device 426 may be a keyboard, a mouse, or the like. The operation device 426 transmits an information signal representing information corresponding to a user's operation to the processor 420. The processor 420 controls the printing system 300 based on the information signal transmitted from the operation device 426.

[0210] The display device 428 displays various types of information in the printing system 300 based on a display signal sent from the processor 420. The display device 428 may be configured as a touch panel and integrated with the operation device 426.

[0211] The printing system 300 includes a sensor 430. The sensor 430 transmits a detection signal to the processor 420. The processor 420 controls the printing system 300 based on the detection signal transmitted from the sensor 430.

[0212] The processor 420 includes a system controller 440. The system controller 440 transmits command signals to each unit of the printing system 300 and controls the printing system 300 in an overall manner.

[0213] The processor 420 includes a transport control unit 442. The transport control unit 442 controls a transport device 444 based on a command signal sent from the system controller 440. The transport device 444 transports the paper 320 along a paper transport path from the paper feed device 302 to the paper discharge device 308 shown in FIG. 9. The transport device 444 、 It includes a mechanism for rotating the payout roll 322, a mechanism for rotating the print drum 332, a paper transport unit 340, and a mechanism for rotating the take-up roll 350.

[0214] The processor 420 includes a jetting control unit 446. The jetting control unit 446 controls the jetting device 304 based on a command signal sent from the processor 420.

[0215] That is, the jetting control unit 446 controls the ejection timing and ink ejection amount of the inkjet head 330. The jetting control unit 446 performs a correction process for the inkjet head 330.

[0216] The jetting control unit 446 includes an image processing unit, a drive voltage generation unit, and a drive voltage output unit. The image processing unit performs color separation processing, color conversion processing, correction processing, and halftone processing on input image data to generate halftone images for each ink color.

[0217] The drive voltage generating unit generates a drive voltage to be supplied to the inkjet head 330 corresponding to each color based on the halftone image for each color. , increase It is provided with a width circuit and an output circuit, and outputs a drive voltage to a pressure generating element provided in the inkjet head 330 corresponding to each color.

[0218] The processor 420 includes a maintenance control unit 448. The maintenance control unit 448 controls the maintenance device 310 based on a command signal transmitted from the system controller 440. The maintenance control unit 448 shown in FIG. 15 includes components corresponding to the system control unit 120, the travel control unit 122, the head movement control unit 124, and the cleaning liquid deposition control unit 126 shown in FIG. 2. The system controller 440 shown in FIG. 15 has functions corresponding to the system control unit 120 shown in FIG. 2.

[0219] The drying control unit 450 controls the drying device 306 based on a command signal transmitted from the system controller 440. That is, the drying control unit 450 controls the temperature and airflow of the drying unit 342.

[0220] The hardware structure of the processor 420 shown in FIG. 15 is the same as that of the processor 100 shown in FIG.

[0221] The memory 422 includes a program memory 460. The program memory 460 stores programs containing instructions to be executed by the processor 420. The program memory 460 stores instructions included in programs corresponding to the paper transport function, the jetting function, the maintenance function, and the drying function.

[0222] The memory 422 includes a parameter memory 462. The parameter memory 462 stores various parameters that the processor 420 refers to when executing various programs.

[0223] The memory 422 includes a data memory 464. The data memory 464 stores various data acquired using the communication interface 424. The processor 420 reads the data stored in the data memory 464 and performs various calculations using the read data. The memory 422 shown in FIG. 15 includes the memory 102 shown in FIG. 2. The memory 422 shown in FIG. 15 uses the same hardware as the memory 102 shown in FIG. 2.

[0224] [Head maintenance procedure] 16 is a flowchart showing the steps of a head maintenance method according to an embodiment. In a maintenance start command acquisition step S10, the maintenance control unit 448 shown in FIG. 15 acquires a maintenance start command. After the maintenance start command acquisition step S10, the process proceeds to a head movement start step S12.

[0225] In the head movement start step S12, the maintenance control unit 448 starts the movement of the inkjet head 330. For example, the maintenance control unit 448 moves the inkjet head 330 from the capping position to the printing position.

[0226] In the cleaning liquid application step S14, the maintenance control unit 448 applies specified cleaning liquid application conditions to apply cleaning liquid to the web 384. The cleaning liquid application conditions include the amount of cleaning liquid to be applied per unit area.

[0227] In the web running start step S16, the maintenance control unit 448 applies the specified web running conditions to start running of the web 384 shown in Fig. 10. The web running conditions include the web running speed.

[0228] In the pressing step S18, the maintenance control unit 448 presses the web 384 provided in the cleaning unit 382 against the nozzle surface 331 of the inkjet head 330. Specified pressing conditions are applied to the pressing of the web 384 against the nozzle surface 331. The specified pressing conditions include the pressure applied to the nozzle surface 331.

[0229] That is, in the pressing step S18, the maintenance control unit 448 raises the cleaning device 380 from the standby position to the wiping position, and applies a specified pressure to press the traveling web 384 against the nozzle surface 331 of the inkjet head 330 that is passing the wiping position. As a result, the web 384 applies cleaning liquid to the nozzle surface 331 and wipes the nozzle surface 331.

[0230] The order of the steps from the head movement start step S12 to the pressing step S18 can be changed as shown in Fig. 16. Furthermore, the processing periods of the steps from the head movement start step S12 to the pressing step S18 may overlap.

[0231] A maintenance end command acquisition determination step S20 is performed during the wiping process of the nozzle surface 331 of the inkjet head 330. In the maintenance end command acquisition determination step S20, the maintenance control unit 448 determines whether or not a maintenance end command has been acquired.

[0232] In the maintenance end command acquisition determination step S20, if the maintenance control unit 448 determines that a maintenance end command has not been acquired, the determination is No. If the determination is No, the maintenance end command acquisition determination step S20 continues until the determination is Yes in the maintenance end command acquisition determination step S20.

[0233] On the other hand, if the maintenance control unit 448 determines that it has received a maintenance end command in the maintenance end command acquisition determination step S20, a "Yes" determination is made. If the determination is "Yes," the process proceeds to the pressure release step S22, the cleaning liquid application stop step S24, and the web running stop step S26.

[0234] In the pressure release step S22, the maintenance control unit 448 separates the web 384 from the nozzle surface 331. Specifically, the maintenance control unit 448 moves the cleaning unit 382 to the standby position.

[0235] In the cleaning liquid application stopping step S24, the maintenance control unit 448 stops the application of cleaning liquid to the web 384. In the web running stopping step S26, the maintenance control unit 448 stops the running of the web 384.

[0236] 16, the order of the pressure release step S22, the cleaning liquid application stop step S24, and the web running stop step S26 may be reversed, or the periods during which each step is performed may overlap, as with the cleaning liquid application step S14, etc. After the web 384 is separated from the nozzle surface 331, the process proceeds to the head movement stop step S28.

[0237] In the head movement stopping step S28, the maintenance control unit 448 monitors whether the inkjet head 330 has reached the printing position, and stops the movement of the inkjet head 330 when the inkjet head 330 has reached the printing position.

[0238] 16 may include a cleaning liquid wiping step of applying a wet web 384 to wipe the nozzle surface 331, and then applying a dry web to wipe the cleaning liquid from the nozzle surface 331. The head maintenance method shown in Fig. 16 may also be performed after a purging process has been performed on the inkjet head 330 using the cap device 390 shown in Fig. 11.

[0239] The head maintenance method shown in Fig. 16 is also applied to the head maintenance system 1 shown in Fig. 1. In the head maintenance method applied to the head maintenance system 1, the running control unit 122 and the like provided in the processor 100 shown in Fig. 2 are applied instead of the maintenance control unit 448 shown in Fig. 15.

[0240] [ink] The inkjet head 50 shown in Figure 1 uses aqueous ink. The ink contains inorganic pigments such as carbon black for black ink and titanium oxide for white ink. The concentration of the inorganic pigments can be in the range of 8 to 16 mass percent.

[0241] The ink contains one or more types of polymer particles, which provide a certain level of abrasion resistance to the printed image. Examples of polymer particles include thermoplastic, thermosetting, or modified acrylic, epoxy, polyurethane, polyether, polyamide, unsaturated polyester, phenol, silicone, or fluorine-based resins; polyvinyl resins such as vinyl chloride, vinyl acetate, polyvinyl alcohol, or polyvinyl butyral; polyester resins such as alkyd resins and phthalic acid resins; melamine resins, melamine formaldehyde resins, aminoalkyd co-condensation resins, and urea resins. Fat etc. Examples of suitable resin particles include those having anionic groups, such as amino-based materials, copolymers or mixtures thereof.

[0242] Of these, anionic acrylic resins can be obtained, for example, by polymerizing an acrylic monomer having an anionic group and, if necessary, other monomers copolymerizable with the anionic group-containing acrylic monomer in a solvent.

[0243] Examples of anionic group-containing acrylic monomers include acrylic monomers having one or more groups selected from the group consisting of a carboxyl group, a sulfonic acid group, and a phosphonic acid group. Among these, acrylic monomers having a carboxyl group, such as acrylic acid, methacrylic acid, crotonic acid, ethacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid, and fumaric acid, are preferred, with acrylic acid or methacrylic acid being particularly preferred.

[0244] Polymer particles are used in terms of ejection stability and liquid stability when pigments are used. perspective In particular, from the viewpoint of dispersion stability, self-dispersing polymer particles are preferred, and self-dispersing polymer particles having a carboxyl group are more preferred.

[0245] The self-dispersing polymer particles refer to particles of a water-insoluble polymer that can be dispersed in an aqueous medium in the absence of other surfactants by virtue of functional groups, particularly acidic groups or salts thereof, that the polymer itself has, and that does not contain a free emulsifier.

[0246] The ink contains water. From the viewpoint of ensuring stability and ejection reliability, the amount of water added to all ink compositions is preferably in the range of 10% by mass to 99% by mass. The amount of water added to all ink compositions is more preferably 30% by mass to 80% by mass. The amount of water added to all ink compositions is even more preferably 50% by mass to 70% by mass.

[0247] The ink contains a solvent. The solvent may be the same as that used in the cleaning liquid. The ink may contain one type of solvent or two or more types of solvents. The solvent content is preferably in the range of 1% by mass to 60% by mass. A more preferred solvent content is in the range of 5% by mass to 40% by mass, and an even more preferred solvent content is in the range of 5% by mass to 30% by mass.

[0248] In addition to the above essential components, the ink may contain other components, such as additives such as surfactants, ultraviolet absorbers, anti-fading agents, anti-fungal agents, pH adjusters, rust inhibitors, antioxidants, emulsion stabilizers, preservatives, antifoaming agents, viscosity adjusters, dispersion stabilizers, and chelating agents.

[0249] [Cleaning solution] The cleaning liquid contains a solvent that has a certain degree of solubility for the solidified ink adhering to the nozzle surface 331. This maintains a certain degree of wiping performance when wiping the nozzle surface 331. The cleaning liquid may contain one type of solvent, or two or more types of solvents.

[0250] Examples of compounds that can be used as solvents include diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, and dipropylene glycol monomethyl ether. Ru Examples include:

[0251] The above-described embodiments of the present invention may be modified, added, or deleted as appropriate within the scope of the spirit of the present invention. The present invention is not limited to the above-described embodiments, and many modifications may be made by a person skilled in the art within the technical concept of the present invention. Furthermore, the embodiments, modifications, and applications may be implemented in appropriate combinations. [Explanation of symbols]

[0252] 1 Head Maintenance System 2. Head moving device 3 Cleaning device 4. Cleaning liquid application device 10. Web 12 cases 14 Supply shaft 16 Winding shaft 18 Pressure roller 20 Front guide section 20A guide roller 20B guide roller 20C guide roller 22 Rear guide section 22A Guide Roller 22B guide roller 24 Feed roller 32 Supply shaft rotation drive motor 34 Winding shaft rotation drive motor 36 Feed roller rotation drive motor 38 Control circuit 50 Inkjet head 52 Nozzle surface 56 Spring 60 ball screw 62 Carriage 64 Head movement motor 70 Cleaning solution tank 72 Cleaning fluid flow path 74 Cleaning fluid pump 100 processors 102 memory 104 Communication Interface 106 Operating device 108 Display device 120 System control unit 122 Travel control unit 124 Head movement control unit 126 Cleaning liquid application control unit 128 Web running device 140 program memory 142 parameter memory 144 data memory 180 curve 182 Curve 191 Web 192 Web 193 Web 194 Web 195 Web 196 Web 197 Web 200 straight line 202 straight line 210 straight line 211 Plot 212 straight line 213 Plot 214 straight line 215 plots 217 Plot 220 straight line 222 straight line 223 Plot 224 plots 225 plots 226 Plot 227 Plot 228 plots 300 Printing System 302 Paper feeder 304 Jetting Device 306 Drying equipment 308 Paper ejection device 310 Maintenance Equipment 320 Paper 322 Payout roll 330 Inkjet head 330C inkjet head 330K inkjet head 330M inkjet head 330Y inkjet head 331 Nozzle surface 331C Nozzle surface 332 Printing drum 332A Outer surface 334 Inline Sensor 340 Paper transport unit 342 Drying Unit 350 winding roll 360 Head Moving Device 362 Horizontal movement mechanism 364 Guide Rail 366 Ball Screw 368 Nut 370 Motor 372 frames 380 Cleaning Device 382 Cleaning Unit 382C Cyan Head Cleaning Unit 382K Black Head Cleaning Unit 382M Magenta Head Cleaning Unit 382Y Yellow Head Cleaning Unit 384 Web 384C Web 384K Web 384M Web 384Y Web 390 Capping device 392C Cap 392K Cap 392M Cap 392Y Cap 400 Head Module 402 Bar Frame 410 Nozzle opening 420 processor 422 memory 424 Communication Interface 426 Operating device 428 Display Device 430 Sensors 440 System Controller 442 Transport control unit 444 Transport Equipment 446 Jetting control section 448 Maintenance Control Unit 450 Drying control unit 460 program memory 462 parameter memory 464 data memory S10~S28 Head maintenance steps

Claims

1. a wiping device including a wiping sheet for wiping the nozzle surface of the inkjet head; a relative movement device that moves the inkjet head and the wiping sheet relative to each other; a pressing device that presses the wiping sheet against the nozzle surface; Equipped with The wiping device is a head maintenance system including the wiping sheet, the value of which compression linearity measured using a compression tester is in the range of 0.3 or more and less than 0.

6.

2. The head maintenance system of claim 1, wherein the wiping device is provided with a wiping sheet that satisfies dT / T0≦−1.1×LC+0.7, where T0 is the uncompressed thickness when a specified pressure is not applied, dT is the compressed thickness when the specified pressure is applied, and LC is the compression linearity.

3. The head maintenance system of claim 2, wherein the wiping device is provided with a wiping sheet in which the uncompressed thickness T0, the compressed thickness dT, and the compression linearity LC satisfy 0.4≦dT / T0≦−1.1×LC+0.

7.

4. The head maintenance system of claim 2 or 3, wherein the wiping device is provided with a wiping sheet in which the uncompressed thickness T0, the compressed thickness dT, and the compression linearity LC satisfy -1.2 x LC + 0.7 ≦ dT / T0 ≦ -1.1 x LC + 0.

7.

5. The head maintenance system according to claim 1 , further comprising a cleaning liquid applying device that applies cleaning liquid to at least one of the nozzle surface and the wiping sheet.

6. one or more processors, 6. The head maintenance system according to claim 5, wherein the processor controls the cleaning liquid application device so that the amount of cleaning liquid applied from the cleaning liquid application device is in the range of 0.41 × WC + 0.01 milliliters per square centimeter or more and 0.76 × WC + 0.02 milliliters per square centimeter or less, when the compression work WC of the wiping sheet measured using the compression tester is WC and the compression work WC is 0.03 gram-force per centimeter or more and 0.59 gram-force per centimeter or less.

7. 7. The head maintenance system according to claim 5, further comprising a cleaning liquid wiping device that uses a dry wiping sheet to wipe off cleaning liquid adhering to the nozzle surface.

8. The head maintenance system according to claim 1 , wherein the pressing device applies a pressure of 5 kilopascals or more and 20 kilopascals or less to the nozzle surface.

9. An inkjet head; a maintenance device for the inkjet head; Equipped with The maintenance device includes: a wiping sheet for wiping the nozzle surface of the inkjet head; a relative movement device that moves the inkjet head and the wiping sheet relative to each other; a pressing device that presses the wiping sheet against the nozzle surface; Equipped with A printing system in which the wiping sheet has a compression linearity value measured using a compression tester in the range of 0.3 or more and less than 0.

6.

10. The printing system according to claim 9 , wherein the inkjet head has a water-repellent film formed on the nozzle surface, the water-repellent film having water repellency against the ink ejected from the inkjet head.

11. pressing a wiping sheet onto a nozzle surface of the inkjet head to wipe the nozzle surface; moving the inkjet head and the wiping sheet relative to each other; a head maintenance method for wiping the nozzle surface using the wiping sheet, A head maintenance method using the wiping sheet, wherein the value of compression linearity measured using a compression tester is in the range of 0.3 or more and less than 0.6.

Images