JP2018094868A - Inkjet printer and method for cleaning ink head in inkjet printer - Google Patents

Abstract

An object of the present invention is to prevent a mixed state caused by different types of ink inside an inkjet nozzle. In the ink jet printer that performs the cleaning process by releasing the sealing of the opening by the cap member after the ink is sucked from the ink jet nozzle by the suction pump, the suction is performed in the cleaning process. After the ink is sucked by the pump, there is pump control means for feeding the ink to the ink head by the liquid feed pump so that the pressure in the ink jet nozzle is equal to or higher than atmospheric pressure. [Selection] Figure 7

Description

  The present invention relates to an inkjet printer and an ink head cleaning method in an inkjet printer. More specifically, the present invention relates to an ink jet printer that cleans an ink head having a plurality of ink jet nozzles that eject ink toward a medium by an ink jet method, and a method for cleaning the ink head in the ink jet printer.

  In this specification, the term “media” refers to various recording media such as plain paper and various recording media such as resin materials such as PVC and polyester, and materials such as aluminum, iron, and wood. Is included.

  Further, in the present specification, the “inkjet method” means various conventionally known methods, including various continuous methods such as a binary deflection method or a continuous deflection method, and various on-demand methods such as a thermal method or a piezoelectric element method. This means a printing method using an inkjet technique according to the above method.

  Furthermore, the atmospheric pressure reference (standard atmospheric pressure 1 atm = 0 kPa (G)) is used for the pressure notation in this specification. Therefore, a pressure higher than “standard atmospheric pressure 1 atm = 0 kPa (G)” is a positive pressure, and a pressure lower than “standard atmospheric pressure 1 atm = 0 kPa (G)” is a negative pressure.

  Conventionally, a plurality of different colors are applied to an ink head having a plurality of ink jet nozzles that respectively eject a plurality of different colors of ink by an ink jet method on a surface facing a recording paper as a medium, which is controlled by a microcomputer. Ink is supplied to each of the recording papers, and a plurality of supplied inks of different colors are ejected onto the recording paper from ink jet nozzles set to correspond to the inks of the respective colors, and color printing is performed on the recording paper. Inkjet printers are known that perform.

  In the ink head of such an ink jet printer, when bubbles are mixed in the ink jet nozzle or the ink is aggregated in the ink jet nozzle, the ink jet nozzle is clogged and the ink discharge is defective.

  When ink ejection failure occurs in the ink jet nozzles of the ink head, a cleaning process for cleaning the ink jet nozzles of the ink head described below has been performed.

  This cleaning process means that the following processes are sequentially performed. That is, first, the surface on which the ink jet nozzle of the ink head is formed by the cap member of the cap device (in this specification, the “surface on which the ink jet nozzle of the ink head is formed” is appropriately referred to as “ink jet nozzle surface”. .) Is capped (sealed). Next, in this state, the suction pump is operated to make the capped inkjet nozzle surface have a negative pressure. As a result, the ink in the ink head is forcibly sucked from the ink jet nozzle toward the cap member, thereby eliminating bubbles and ink aggregation in the ink jet nozzle. Thereafter, the capping of the ink head by the cap member is released, the ink head is moved from the cap device to the wiper device, and the inkjet nozzle surface is wiped by the wiper blade of the wiper device.

  Incidentally, for example, an inkjet printer disclosed in Japanese Patent No. 5980390 discloses an ink cartridge that stores ink, an ink head that includes an inkjet nozzle that discharges ink, and an ink cartridge that sends ink from the ink cartridge toward the ink head. A pressure control valve for supplying liquid, a pressure control valve provided in an ink path communicating with the ink cartridge and the pressure pump, and maintaining the ink in the ink jet nozzle of the ink head in a negative pressure state; It has a microcomputer that controls the operation and stop of the pressure pump. The pressure control valve is not electrically controlled, and closes the ink path when the pressurizing pump is stopped under the control of the microcomputer.

  In the ink jet printer having the above-described configuration, the pressure inside the ink jet nozzle of the ink head is always maintained when the ink is not ejected from the ink jet nozzle of the ink head by the cooperation of the pressure control valve and the pressure pump. The negative pressure is maintained. In such an ink jet printer, when ink is not ejected from the ink jet nozzles of the ink head, the inside of the ink jet nozzles of the ink head is always maintained in a negative pressure state, so that ink is sucked from the ink head in the cleaning process. Until the wiping with the wiper blade was performed later, a back flow phenomenon occurred in which the ink adhered to the ink jet nozzle surface flowed back into the ink jet nozzle.

  When the above-described reverse flow phenomenon occurs in an ink head in which an inkjet nozzle is configured to eject different types of ink, such as ink of various colors or clear ink, it is different from the type of ink ejected by the inkjet nozzle. It has occurred that various types of ink flow back into the inkjet nozzle. When ink of a different type from the type ejected by the ink jet nozzle flows back into the ink jet nozzle, mixing with different types of ink occurs inside the ink jet nozzle of the ink head. Deteriorates.

  For this reason, in the conventional ink jet printer, in order to prevent the deterioration of the print quality due to the mixing of different types of ink inside the ink jet nozzle described above, after the cleaning process, the ink is ejected from the ink jet nozzle before starting the printing. A considerable amount of flushing was performed to eliminate the mixed state of different types of ink inside the inkjet nozzle.

  For this reason, the conventional ink jet printer has a problem in that the amount of ink consumed by flushing that ejects ink from the ink jet nozzles before starting printing increases.

Japanese Patent No. 5980390

  The present invention has been made in view of the above-described problems in the prior art, and an object of the present invention is to prevent the occurrence of a mixed state due to different types of ink inside the inkjet nozzle, and to perform such mixing. The present invention provides an ink jet printer and an ink head cleaning method in an ink jet printer that can reduce the amount of ink consumed to eliminate the state.

  In order to achieve the above object, according to the present invention, in the cleaning process, in order to suck ink from the ink jet nozzles of the ink head, the ink jet nozzle surface on which the ink jet nozzles of the ink head are formed has a negative pressure. After the suction of the ink from the ink jet nozzle is completed by setting the ink jet nozzle surface to a negative pressure, the pressure in the ink jet nozzle of the ink head is once set to atmospheric pressure or positive pressure. In addition, in the case of a positive pressure, it is preferable to set it as a slight positive pressure. This prevents ink adhering to the ink jet nozzle surface from flowing back into the ink jet nozzle and prevents the mixed state of different types of ink inside the ink jet nozzle of the ink head.

  According to the present invention, since the mixed state due to different types of inks inside the inkjet nozzle is prevented, the mixed state described above is performed by flushing the ink from the inkjet nozzle before starting printing after the cleaning process. There is no need to eliminate the ink consumption, and it is possible to reduce the ink consumption due to the flushing before the start of printing.

  That is, an ink jet printer according to the present invention seals an ink head in which a plurality of ink jet nozzles for discharging different types of ink, a liquid feed pump for feeding the ink to the ink head, and an opening of the ink jet nozzle. A cap member that stops, a suction pump that sucks the ink from the inkjet nozzle, and a wiper device that cleans the inkjet nozzle surface on which the opening of the inkjet nozzle is located with a wiper blade. In the ink jet printer that performs the cleaning process by releasing the sealing of the opening by the cap member after the ink is sucked from the ink jet nozzle, the ink is discharged by the suction pump in the cleaning process. After suction, by the liquid feeding pump to feeding the ink to the ink head, in which to have a pump control means for the inside the ink jet nozzle and above atmospheric pressure.

  The ink jet printer according to the present invention is the ink jet printer according to the present invention described above, wherein the pressure above the atmospheric pressure is 0 to 1 kPa (G).

  The ink jet printer according to the present invention is the ink jet printer according to the present invention described above, wherein the different types of inks are inks having different colors.

  The ink head cleaning method in the ink jet printer according to the present invention includes an ink head having a plurality of ink jet nozzles for discharging different types of ink, a liquid feed pump for feeding the ink to the ink head, and the ink jet. Inkjet having cap member for sealing nozzle opening, suction pump for sucking ink from inkjet nozzle, and wiper device for cleaning inkjet nozzle surface on which inkjet nozzle opening is located with wiper blade A method for cleaning an ink head in a printer, wherein after the ink is sucked from the inkjet nozzle by the suction pump, the sealing of the opening by the cap member is released, and the cleaning is performed. In the cleaning method of an ink jet printer that performs a cleaning process, after the ink is sucked by the suction pump in the cleaning process, the ink is fed to the ink head by the liquid feed pump, and the inside of the ink jet nozzle is at atmospheric pressure or higher. The pressure is set as follows.

  The ink head cleaning method in the ink jet printer according to the present invention is the ink head cleaning method in the ink jet printer according to the present invention, wherein the pressure above the atmospheric pressure is 0 to 1 kPa (G). .

  The ink head cleaning method in the ink jet printer according to the present invention is the ink head cleaning method in the ink jet printer according to the present invention, wherein the different types of ink are inks of different colors.

  Since the present invention is configured as described above, it is possible to prevent the occurrence of a mixed state due to different types of ink inside the inkjet nozzle, and to reduce the amount of ink consumed to eliminate such a mixed state. It has an excellent effect that it can be reduced.

FIG. 1 is a schematic configuration perspective view showing an example of an embodiment of an ink jet printer according to the present invention. FIG. 2 is an explanatory diagram schematically showing an ink path from the ink cartridge to the waste tank ink in the ink jet printer shown in FIG. FIG. 3 is a configuration explanatory diagram illustrating an example of a configuration of a pressurizing pump (liquid feeding pump) in the ink jet printer illustrated in FIG. 1. FIG. 4 is an explanatory diagram illustrating an example of a configuration of a suction pump in the ink jet printer illustrated in FIG. 1. FIG. 5 is an explanatory diagram schematically showing the positional relationship between the ink jet nozzle surface on which the ink jet nozzles of the ink head are formed and the cap member. 5A shows the capping position, FIG. 5B shows the standby position, and FIG. 5C shows the in-cap flushing position. FIG. 6 is a block configuration explanatory diagram showing a functional configuration related to the implementation of the present invention of the microcomputer in the ink jet printer shown in FIG. FIG. 7 is a flowchart showing a cleaning processing routine executed by the ink jet printer according to the example of the embodiment of the present invention. FIGS. 8A and 8B are configuration explanatory views schematically showing ink paths of the ink jet printer according to the second embodiment of the present invention. 8A shows a state in which the bypass path valve valve is opened, and FIG. 8B shows a state in which the bypass path valve valve is closed.

  Hereinafter, an example of an embodiment of an ink jet printer and an ink head cleaning method in the ink jet printer according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a schematic configuration showing an example of an embodiment of an ink jet printer according to the present invention.

  The ink jet printer 10 includes a fixed base member 14 that is supported by a base member 12 and is disposed extending in the main scanning direction. Side members 16L and 16R are disposed on the left and right ends of the base member 14, and a side unit 18 is disposed on the side member 16R side.

  The inkjet printer 10 includes a central wall 20 that connects the left and right side members 16L and 16R, and a guide rail 22 is disposed on the wall surface of the central wall 20 so as to extend in the main scanning direction.

  Reference numeral 24 is a wire arranged in parallel with the wall surface of the central wall 20 so as to be movable in the main scanning direction. The carriage 26 is fixedly disposed on the wire 24 and is slidably mounted on the guide rail 22. An ink head 30 is mounted on the carriage 26 so as to face a recording paper 28 that is a medium positioned on the base member 14, and a damper device 32 connected to the ink head 30 is mounted. The ink head 30 is formed with a plurality of inkjet nozzles (not shown) that respectively eject a plurality of different colors of ink.

  The overall operation of the ink jet printer 10 is controlled by the microcomputer 34.

  In the inkjet printer 10, the recording paper 28 is used as the medium as described above. The recording paper 28 is supplied onto the base member 14 by a paper feeding device (not shown), has a predetermined length in the main scanning direction as the width direction, and is a direction orthogonal to the main scanning direction, that is, recording. It is conveyed in the longitudinal direction of the paper 28. The direction orthogonal to the main scanning direction, that is, the conveyance direction of the recording paper 28 and the longitudinal direction of the recording paper 28 are referred to as “sub-scanning direction”.

  In the inkjet printer 10, printing is performed on the recording paper 28 under the control of the microcomputer 34.

  That is, when the wire 24 is moved by winding the wire 24 according to the control of the microcomputer 34, the carriage 26 reciprocates in the forward direction in the main scanning direction and the return direction (return direction) as the wire 24 moves. Moving. As a result, the damper device 32 and the ink head 30 mounted on the carriage 26 travel in the main scanning direction (outward path) and return direction (return path) on the recording paper 28 supplied onto the base member 14 by the paper feeder. And reciprocally move together to print on the recording paper 28.

  In the inkjet printer 10, a waste liquid tank 42 is disposed on the base member 14, and an ink path 100 is formed from the ink cartridge 36 detachably disposed on the side unit 18 to the waste liquid tank ink 42. (See FIG. 2). In addition, as the ink cartridge 36, a plurality of ink cartridges 36 each storing ink of different colors are disposed.

  The ink jet printer 10 is provided with a cap device 38 for capping the ink jet nozzle opening provided on the ink jet nozzle surface 30 a of the ink head 30. Further, the ink jet printer 10 is provided with a wiper device 39 that wipes the ink jet nozzle surface 30a of the ink head 30 with a wiper blade (not shown).

  Reference numeral 40 denotes an operation panel provided with an operator for the operator to control the operation of the ink jet printer 10. The operation panel 40 is provided with a display device 40 a for displaying the operation state of the inkjet printer 10.

  Here, FIG. 2 is an explanatory diagram schematically showing an ink path 100 from the ink cartridge 36 to the waste liquid tank ink 42 in the inkjet printer 10 shown in FIG. In FIG. 2, in order to simplify the explanation and facilitate understanding of the present invention, the path from the upstream ink cartridge 36 to the inkjet nozzle of the downstream ink head 30 is one color. Fig. 4 shows an ink path for ink. When a plurality of colors of ink are used, a path from the upstream ink cartridge 36 to the inkjet nozzles of the downstream ink head 30 is provided for each color.

  The ink path 100 shown in FIG. 2 is connected to one end 102a so as to communicate with the ink cartridge 36, and connected to the other end 102b so that one end 104a of the connector 104 communicates. A flexible ink supply tube 102 is provided. The end 102b of the ink supply tube 102 and the end 104a of the connector 104 are detachably connected.

  The ink cartridge 36 stores ink to be supplied to the ink head 30, and a sensor (not shown) that detects the amount of ink stored in the ink cartridge 36 is provided.

  The connector 104 has a hollow pipe shape having a bendable bellows-like portion, and a damper device 32 is connected to the other end 104b.

  The damper device 32 is mounted on the carriage 26 together with the ink head 30 and includes a storage chamber (not shown) that temporarily stores the ink that has passed through the connector 104. The damper device 32 absorbs pressure fluctuations of the ink in the ink path 100 when the carriage 26 reciprocates with respect to the recording paper 28. The damper device 32 includes an ink storage amount detection device that detects the amount of ink stored in the damper device 32.

  The ink storage amount detection device of the damper device 32 detects, for example, whether or not the amount of ink stored in the storage chamber of the damper device 32 is a predetermined amount or less. Here, if the amount of ink that can be stored in the storage chamber of the damper device 32 is 6 cc, for example, the predetermined amount is 3 to 4 cc, for example. When the ink storage amount detection device of the damper device 32 detects that the amount of ink stored in the storage chamber has become a predetermined amount or less, the pressurization pump 101 (described later) is operated by automatic control of the microcomputer 34. Then, a predetermined amount of ink is pressurized from the pressurizing pump 101 to the storage chamber of the damper device 32 and fed.

  Since such an ink storage amount detection device is a known technique disclosed in, for example, Japanese Patent No. 5980390, the detailed configuration and description of the operation are omitted.

  An ink head 30 having an inkjet nozzle that communicates with a storage chamber of the damper device 32 is connected to the damper device 32, and the ink stored in the ink cartridge 36 is supplied to the ink head 30 via the damper device 32. Is done. The ink supplied to the ink head 30 is ejected from an ink head nozzle having an opening formed on the inkjet nozzle surface 30a. As will be described in detail later, the ink jet nozzle 30 of the ink head 30 is always at a negative pressure when the ink is not being discharged by the cooperation of the pressure control valve 108 (described later) and the pressure pump 101. It is maintained to be in a state.

  In the ink supply tube 102, a valve valve 106 is provided between one end portion 102a and the pressure control valve 108. The valve valve 106 is constituted by a solenoid valve, for example. The valve valve 106 opens the valve valve 106 to allow the ink supply from the ink cartridge 36 to the ink head 30, or closes the valve valve 106 to stop the ink supply from the ink cartridge 36 to the ink head 30. Can be selectively controlled.

  In the ink supply tube 102, the pressure control valve 108 and the pressurizing pump 101 are disposed between the valve valve 106 and the damper device 32. The pressure control valve 108 is disposed on the upstream side, and the pressurizing pump 101 is disposed on the downstream side.

  The pressure control valve 108 maintains the ink in the ink jet nozzles of the ink head 30 in a negative pressure state. The pressure control valve 108 is not electrically controlled. When the pressure pump 101 is stopped by the control of the microcomputer 34, the ink supply tube 102 is closed and the ink path 100 is closed.

  When the pressurization pump 101 is operated by the automatic control of the microcomputer 34, the ink is pressurized and sent from the ink cartridge 36 toward the damper device 32, and when the operation is stopped by the automatic control of the microcomputer 34, the ink cartridge 36 is stopped. From the ink to the damper device 32 is stopped.

  By providing the ink supply tube 102 with the pressure control valve 108 and the supply pump 101, when the pressure pump 101 is stopped, the ink supply tube 102 is closed by the pressure control valve 108 and the ink path 100 is closed. . Thereby, when the ink jet nozzle of the ink head 30 is not ejecting ink, the pressure inside the ink jet nozzle of the ink head 30 is always maintained to be in a negative pressure state. Therefore, when the ink jet printer 10 is not used, ink leakage from the ink head 30 can be accurately prevented. In addition, the ink cartridge 36 can be disposed at a position higher than the ink head 30, and the degree of freedom in design (layout) in the height direction can be increased. Further, in this configuration, when the ink jet printer 10 is not used, it is not necessary to continue crushing a part of the ink supply tube 102, and ink can be stably supplied to the ink head 30 when the ink jet printer 10 is used.

  Since the pressure control valve 108 and the pressurizing pump 101 described above are conventionally known techniques disclosed in, for example, Japanese Patent No. 5980390, the detailed configuration and description of the operation are omitted.

  In the present embodiment, as the pressurizing pump 101, a conventionally known tube pump that crushes a tube by rotating a roller and pressurizes and feeds ink is used. FIG. 3 is a configuration explanatory diagram illustrating an example of the configuration of the pressurizing pump 101. The pressurizing pump 101 is provided between the valve valve 106 and the connector 104 in the ink supply tube 102. Since the tube pump itself is a conventionally known technique, a detailed description of the pressurizing pump 101 is omitted, but the pressurizing pump 101 has a circular pedestal that rotates in the direction of arrow A around the center C1. 101a and rollers 101b and 101c respectively disposed on the circumference of the circular pedestal 101a. The rollers 101b and 101c are arranged at point symmetry positions with the central portion C1 as a symmetric point. In the pressurization pump 101, the rollers 101b and 101c rotate and move in the direction of the arrow A on the circumference of the circular pedestal 101a by rotating in the direction of the arrow A around the center portion C1 of the circular pedestal 101a. As a result, the pressing state of the internal tube 101d is changed, and ink is fed from the valve valve 106 side to the connector 104 side. In the pressurizing pump 101, rotation of the circular pedestal 101a with a rotation angle of 45 degrees around the center portion C1 is set as one unit of rotation amount (operation amount), that is, unit rotation amount (unit operation amount). ing.

  The pressurizing pump 101 can switch the rotation speed of the rollers 101b and 101c by rotating the circular pedestal 101a around the center C1, and the rotation angle of the rollers can be set to an arbitrary angle. it can.

  Further, as described above, the ink jet printer is provided with the cap device 38 for capping around the ink jet nozzles formed on the ink jet nozzle surface 30a of the ink head 30.

  The cap device 38 includes a cap member 112 that seals an ink jet nozzle opening formed on the ink jet nozzle surface 30a of the ink head 30, and a suction pump 114 that can suck ink in the ink path 100. Has been. The suction pump 114 supplies negative pressure to the cap member 112 that seals the ink jet nozzle opening formed on the ink jet nozzle surface 30 a of the ink head 30, and sucks ink in the ink supply path 100.

  Reference numeral 116 denotes a waste liquid tube. One end 116 a is connected to the cap member 112 and the other end 116 b is connected to the waste liquid tank 118. The suction pump 114 is provided between one end 116a and the other end 116b of the waste liquid tube 116.

  As the suction pump 114, it is possible to use various types of conventionally known structures. For example, a tube pump or a trochoid pump can be used, and the ink suction speed can be varied.

  Here, the tube pump and the trochoid pump stop the movement of the roller in the pump at a predetermined position and the state where the suction force is generated by moving the roller in the pump or rotating the gear. When the suction force is released and the air is released to the outside air, the roller movement in the pump is stopped at a predetermined position, or the gear rotation is stopped and the suction force is released to the outside air. The pump can selectively control the closed state.

  Specifically, as the suction pump 114, as shown in FIG. 4, for example, a tube pump having the same configuration as the tube pump disclosed in Japanese Patent No. 4857798 can be used.

  The suction pump 114 shown in FIG. 4 has a circular pedestal 114a that rotates in the direction of arrow B around the center C2 and rollers 114b and 114c that are respectively disposed on the circumference of the circular pedestal 114a. doing. The rollers 114b and 114c are arranged at point-symmetric positions with the center portion C2 as a symmetric point. In the suction pump 114, the rollers 114b and 114c rotate and move in the direction of the arrow B on the circumference of the circular pedestal 114a by rotating in the direction of the arrow B around the central portion C2 of the circular pedestal 114a. The state in which the inner tube 114d is pressed is changed, negative pressure is supplied to the cap member 112 to generate a suction force, and the movement of the rollers 114b and 114c is stopped at a predetermined position to release the suction force. Thus, it is possible to select a state in which the air is released to the outside air and a state in which the movement of the rollers 114b and 114c is stopped at a predetermined position to release the suction force and the air is closed to the outside air. In the suction pump 114, ink suction is performed by changing the moving speed of the rollers 114b and 114c by changing the rotation speed of the rollers 114b and 114c by rotating the circular pedestal 114a around the center portion C2. The speed can be changed.

  In this embodiment, the suction pump 114 sucks 0.05 cc of ink per second when the suction speed is low, and sucks 0.075 cc of ink per second when the suction speed is medium. At high speed, 0.1 cc of ink is sucked per second. The suction speed at which 0.1 cc of ink is sucked per second is the maximum suction speed at which the suction pump 114 operates properly.

  5A, 5B, and 5C schematically show the positional relationship between the ink jet nozzle surface 30a on which the ink jet nozzles of the ink head 30 are formed and the cap member 112. FIG.

  FIG. 5A shows a capping position where the ink head 30 is capping the inkjet surface 30 a by the cap member 112 of the cap device 38. FIG. 5B shows a standby position where the ink head 30 and the cap member 112 are separated by a predetermined distance. FIG. 5C shows the in-cap flushing position (in-CAP FL position) where the cap member 112 is separated from the ink head 30 with a slight gap G (for example, 0.5 mm).

  Next, FIG. 6 is a block diagram illustrating a functional configuration related to the implementation of the present invention of the microcomputer 34 in the inkjet printer 10.

  The microcomputer 34 includes a control unit 202, a storage unit 204, and a pressure pump control unit 206.

  The control unit 202 controls the entire process including the execution of various processes such as a printing process executed by the inkjet printer 10 and a cleaning process described later (see FIG. 7).

  The storage unit 204 stores various information used in various processes such as a printing process and a cleaning process.

  The pressurization pump control unit 206 controls the operation and stop of the pressurization pump 101 during the cleaning process. That is, when the pressurization pump 101 detects by the microcomputer 34 (the control unit 202) that the ink storage amount detection device of the damper device 32 detects that the amount of ink stored in the storage chamber is equal to or less than a predetermined amount, It is automatically controlled to pressurize and feed a set amount of ink to the storage chamber of the damper device 32. In the cleaning process, the pressurization pump control unit 206 stops automatic control of the pressurization pump 101 by the microcomputer 34 (control unit 202), and the pressurization pump 101 is operated under a preset condition while the automatic control is stopped. Operate. When this operation is completed, automatic control by the microcomputer 34 (control unit 202) is resumed.

  In the above configuration, under the control of the microcomputer 34, the ink is supplied from the ink head jet nozzle of the ink head 30 to the recording paper 28 while the valve valve 106 is opened and ink is supplied from the ink cartridge 36 to the ink supply tube 102. The ink is discharged and printed on the storage paper 28.

  Here, ink is ejected from the 30 jet head nozzles of the ink head, and the ink is discharged from the damper device 32 to the ink head 30 along with this. The ink storage amount detection device of the damper device 32 detects the amount of ink stored in the damper device 32.

  When the ink storage amount detection device detects that the amount of ink stored in the damper device 32 is equal to or less than a preset amount, the control unit 202 of the microcomputer 34 operates the pressurizing pump 101 and presets it. The amount of ink thus supplied is sent to the storage chamber of the damper device 32.

  Next, the operation of the inkjet printer 10 will be described with reference to a flowchart of a cleaning process routine executed by the inkjet printer 10 shown in FIG.

  When the ink head 30 is at the capping position (position shown in FIG. 5A) where the ink jet surface 30a is capped by the cap member 112 of the cap device 38, the cleaning process is executed by the operation of the operation panel 40 by the user. When instructed, the cleaning process routine shown in FIG. 7 is started.

  In the cleaning processing routine described below, an operation of changing the positional relationship between the ink head 30, the cap member 112, and the wiper device 39 is performed. Regarding the operation for changing the positional relationship, it is only necessary that the positional relationship between the ink head 30 and the cap member 112 and the wiper device 39 is changed relatively. Either one of the ink head 30 and the cap member 112 is used. Alternatively, both or one or both of the ink head 30 and the wiper device 39 may be moved. Since such a technique for relatively changing the positional relationship between the ink head 30, the cap member 112, and the wiper device 39 is a conventionally known technique, a detailed description of its configuration and operation is omitted.

  In the following description, in order to simplify the description and facilitate understanding of the present invention, the positional relationship between the ink head 30, the cap member 112, and the wiper device 39 is changed by moving the ink head 30. It is assumed that it changes.

  When the cleaning processing routine is started, the ink head 30 is moved at a low speed (for example, 1 cm / sec), the capping by the cap member 112 is released, and the cap member 112 is released (step S702). The ink head 30 is moved to a standby position (a position shown in FIG. 7B) that is separated from the head 112 by a predetermined distance (step S704).

  When the process of step S704 is completed, the process proceeds to the process of step S706. Under the control of the control unit 202 of the microcomputer 34, the suction pump 114 is rotated forward at high speed for 0.914 seconds (“forward rotation” is a suction pump. 114, and the positions of the rollers 114b and 114c of the suction pump 114 are moved to the suction start position.

  When the process of step S706 is completed, the process proceeds to the process of step S708, the ink head 30 is moved to the capping position at a low speed, and the ink jet surface 30a is capped by the cap member 112.

  When the process of step S708 is completed, the process proceeds to the process of step S710. Under the control of the suction pump control unit 208 of the microcomputer 34, the suction pump 114 is rotated forward at a medium speed for 13.7 seconds, and the ink jet nozzle of the ink head 30 is reached. Ink the ink from. The suction amount by which the suction pump 114 is rotated forward at a medium speed for 13.7 seconds and the ink is sucked is determined by the ink storage amount detection device of the damper device 32 and the amount of ink stored in the storage chamber of the damper device 32 is a predetermined amount. The amount of suction that can be detected as follows.

  When the process of step S710 ends, the process proceeds to step S712, and the process is paused for 11 seconds. The pause time is a time for waiting for the ink in the upstream portion of the ink head 30 to flow below the cap member 112 and the negative pressure on the ink head 30 and the negative pressure on the ink head 30 to become uniform. The negative pressure here is about -0.5 to -1.7 kPa (G).

  When the process of step S712 is completed, the process proceeds to the process of step S714, and the control of the pressurizing pump control unit 206 stops the automatic control of the pressurizing pump 101 by the control unit 202. As a result, the operation of the pressure pump 101 is stopped, and the pressure control valve 108 closes the ink supply tube 102 and closes the ink path 100.

  When the process of step S714 is completed, the process proceeds to the process of step S716, and the pressure pump 101 is rotated forward at a medium speed and at a rotation angle of 180 °. This is the rotational direction in which the liquid is pressurized to 30 and fed.) As a result, the pressure in the ink jet nozzles of the ink head 30 is set to atmospheric pressure (0 kPa (G)) or a positive pressure from atmospheric pressure. In addition, it is preferable to set it as a some positive pressure in the case of a positive pressure from atmospheric pressure, for example, it is preferable to set it as the pressure of 0-1 kPa (G). The pressure varies depending on the viscosity of the ink used.

  The process in step S716 is a process for temporarily reducing the pressure in the ink jet nozzles of the ink head 30 to atmospheric pressure or positive pressure after the suction of the ink from the ink jet nozzles is finished by setting the ink jet nozzle surface 30a of the ink head 30 to a negative pressure. . This prevents ink adhering to the ink jet nozzle surface 30a from flowing back into the ink jet nozzle before wiping by the wiper blade of the wiper device 39, and the ink head 30 has different colors inside the ink jet nozzle. Occurrence of a mixed state (mixed color state) due to ink is prevented.

  When the process of step S716 ends, the process proceeds to the process of step S718, and the control of the pressurizing pump control unit 206 starts the automatic control of the pressurizing pump 101 by the control unit 202. As a result, the pressure pump 101 can be operated. When the pressure pump 101 is operated, the pressure control valve 108 opens the ink supply tube 102 and opens the ink path 100.

  When the process of step S718 is completed, the ink head 30 is moved at a low speed, the capping by the cap member 112 is released and the cap member 112 is released (step S720), and the cap member 112 is slightly spaced from the ink head 30 by the gap G. The ink head 30 is moved to the flushing position in the cap (the FL position in the CAP) (the position shown in FIG. 5C) spaced apart (for example, 0.5 mm) (step S722).

  Since the processing of step S720 and step S722 is performed in a state where ink is accumulated in the cap member 112, it is performed by a slow operation so as not to spill ink from the cap member 112 to the outside.

  When the process of step S722 is completed, the process proceeds to the process of step S724, and the suction pump 114 is driven to perform empty suction for sucking the ink accumulated in the cap member 112 to the waste liquid tank.

  When the process of step S724 is completed, the process proceeds to the process of step S726, the ink head 30 is moved at a low speed, and the inkjet nozzle surface 30a is capped by the cap member 112. As a result, the ink head 30 and the cap member 112 are in the capping position.

  When the process of step S726 is completed, the process proceeds to the process of step S728, and the ink jet nozzle surface 30a is wiped by the wiper blade of the wiper device 39, and the suction pump 114 is driven to remove the ink accumulated in the cap member 112 from the waste liquid tank 42. Perform empty suction to suck in. In the process of step S728, various processes such as releasing the capping of the cap member 112 and driving the wiper blade are sequentially performed at the time of wiping. Therefore, the detailed description of the configuration and operation is omitted.

  When the process of step S728 ends, the process proceeds to step S730, the ink head 30 is moved at a low speed, and the inkjet nozzle surface 30a is capped by the cap member 112. As a result, the ink head 30 and the cap member 112 are in the capping position. When the process of step S730 is finished, this cleaning process routine is finished.

  As described above, according to the ink jet printer 10, in the cleaning process, the ink jet nozzle surface 30a of the ink head 30 is set to a negative pressure in order to suck ink from the ink jet nozzle of the ink head 30. After the suction of the ink from the ink jet nozzle is completed by setting the ink jet nozzle surface 30a to a negative pressure, the pressure in the ink jet nozzle of the ink head 30 is temporarily set to atmospheric pressure or positive pressure by the process of step S716. This prevents the ink adhering to the ink jet nozzle surface 30a of the ink head 30 from flowing back into the ink jet nozzle, and the mixed body (mixed state) of inks of different colors inside the ink jet nozzle of the ink head 30 is prevented. Occurrence is prevented.

  Therefore, according to the inkjet printer 10, since the mixed state (mixed color state) due to the inks of different colors inside the inkjet nozzle after the cleaning process is prevented, the flushing that discharges ink from the inkjet nozzle before starting printing is performed. Therefore, it is not necessary to eliminate the mixed state (color mixture state) described above, and the ink consumption due to the flushing before the start of printing described above can be reduced.

  The above-described embodiments are merely examples, and the present invention can be implemented in various other forms. That is, the present invention is not limited to the above-described embodiment, and various omissions, replacements, and changes can be made without departing from the gist of the present invention.

  For example, the above-described embodiment may be modified as shown in the following (1) to (5).

  (1) The ink jet printer according to the present invention may be configured as shown in FIGS. FIGS. 8A and 8B are structural explanatory views schematically showing ink paths of the ink jet printer according to the second embodiment of the present invention. FIG. 8A shows a state where the bypass path valve valve is opened, and FIG. 8B shows a state where the bypass path valve valve is closed. 2 that are the same as or correspond to those shown in FIG. 2 are denoted by the same reference numerals as those used in FIG. 2, and detailed description of the configuration and operation is omitted.

  According to the second embodiment of the present invention, in the ink path 300 of the ink jet printer, when the pressure pump 101 pressurizes and feeds the ink, the pressure fluctuation applied to the ink is alleviated. For this purpose, a bypass path 302 that constitutes a bypass that bypasses the pressurizing pump 101 is provided. The bypass path 302 is connected by a connecting portion 306a so that one end portion 304a communicates between the pressure control valve 108 of the ink supply tube 102 and the pressurizing pump 101, and the other end portion 304b is ink. A bypass tube 304 connected by a connecting portion 306 b is provided so as to communicate between the pressurizing pump 101 of the supply tube 102 and the damper device 32.

  Here, the connecting portion 306a is located on the suction port for sucking ink of the pressurizing pump 101, and the connecting portion 306b is located on the discharge port side for ejecting ink of the pressurizing pump 101. That is, one end 304 a of the bypass tube 304 is connected to the suction port side of the pressure pump 101 in the ink supply tube 102, and the other end 304 b of the bypass tube 304 is connected to the pressure pump 101 of the ink supply tube 102. Are connected at the discharge port. Thus, an ink path is formed from the ink cartridge 36 that bypasses without passing through the pressure pump 101 to the waste liquid tank 42.

  A bypass passage valve valve 308 is provided between one end 304 a and the other end 304 b of the bypass tube 304. The bypass path valve valve 308 is constituted by, for example, a solenoid valve. The bypass path valve valve 308 is controlled by the microcomputer 34 to open the bypass path valve valve 308 to allow ink flow in the bypass path 302, and to close the bypass path valve valve 308 in the bypass path 302. The closed state in which the distribution of the ink is prohibited can be selected.

  Here, in the ink path 100 without the bypass path shown in FIG. 2, the inside of the ink path 100 is in a constant negative pressure state only by the suction force of the suction pump 114. In such a case, since the negative pressure in the damper device 32 is small, a large amount of ink is consumed to obtain a large negative pressure state.

  On the other hand, in the ink path 300 provided with the bypass path 302, before the ink is sucked by the suction pump, the bypass path valve valve 308 of the bypass path 302 is opened so that a negative pressure is not consumed without consuming much ink. Can be bigger. Specifically, the negative pressure can be increased without consuming much ink by performing the processing procedure described below.

  First, the automatic control of the pressurizing pump 101 is stopped, and the pressurizing pump 101 is closed. Next, the bypass path valve valve 308 of the bypass path 302 is once opened and closed after a preset time has elapsed. Thereafter, the suction pump 114 sucks ink from the ink jet nozzles of the ink head 30 to increase the negative pressure in the ink path 300. After suction for a preset time by the suction pump 114, the pressure pump 101 is returned to the automatic control state. Then, the inkjet nozzle surface 30 a is prepared by the wiping operation of the wiper device 39.

  By performing the processing procedure described above, the negative pressure can be increased without consuming a large amount of ink, and the amount of ink consumed and the required time can be reduced.

  (2) In the above-described embodiment, in order to facilitate understanding of the present invention, specific numerical values (for example, the rotation speed and rotation angle of the pressure pump 101, the suction speed and suction time of the suction pump 114, etc.) are used. There is.) These specific numerical values in this specification are merely examples for facilitating the understanding of the present invention, and the present invention is not limited to these numerical values, and is appropriately determined according to design conditions and the like. Of course, it may be changed to.

  (3) In the above-described embodiment, the case where inks having different colors are used as different types of ink has been described. However, the present invention is not limited to this. Different types of inks are different in color as well as inks such as clear ink and white ink, and those with the same color but different brightness and viscosity. It shall mean different types of ink.

  (4) In the above-described embodiment, the ink head 30 is moved when the positional relationship between the ink jet nozzle surface 30a of the ink head 30 and the cap member 112 is relatively changed. Of course, it is not possible. For example, the positional relationship between the inkjet nozzle surface 30a of the ink head 30 and the cap member 112 may be relatively changed by moving the cap member 112. Alternatively, the positional relationship between the ink jet nozzle surface 30a of the ink head 30 and the cap member 112 may be relatively changed by moving both the ink head 30 and the cap member 112.

  (5) You may make it combine suitably the embodiment shown above and the modification shown in said (1) thru | or (4).

  The present invention is suitable for use in an ink jet printer that performs predetermined printing by discharging ink from an ink head by an ink jet method.

  DESCRIPTION OF SYMBOLS 10 Inkjet printer, 12 base member, 14 base member, 16L side member, 16R side member, 18 side unit, 20 center wall, 22 guide rail, 24 wire, 26 carriage, 28 recording paper, 30 ink head, 30a Inkjet nozzle surface, 32 Damper device, 34 Microcomputer, 36 Ink cartridge, 38 Cap device, 39 Wiper device, 40 Operation panel, 40a Display device, 42 Waste liquid tank, 100 Ink path, 101 Pressure pump (liquid feed pump) , C1 center part, 101a circular pedestal part, 101b roller, 101c roller, 101d tube, 102 ink supply tube, 102a end part, 102b end part, 104 connector, 104a end part, 104b end part, 106 valve Valve, 108 Pressure control valve, 112 Cap member, 114 Suction pump, C2 center part, 114a Circular pedestal part, 114b Roller, 114c Roller, 114d tube, 116 Waste liquid tube, 116a end part, 116b end part, 202 Control part, 204 Storage unit, 206 Pressure pump control unit (pump control means), 300 Ink path, 302 Bypass path, 304 Bypass tube, 304a end, 304b end, 306a connection, 306b connection, 308 Bypass path valve valve

Claims (6)

An ink head formed with a plurality of inkjet nozzles for discharging different types of ink;
A liquid feed pump for feeding the ink to the ink head;
A cap member for sealing the opening of the inkjet nozzle;
A suction pump for sucking the ink from the inkjet nozzle;
A wiper device that cleans an inkjet nozzle surface on which the opening of the inkjet nozzle is located with a wiper blade, and after the ink is sucked from the inkjet nozzle by the suction pump, the cap member opens the opening In an inkjet printer that releases the sealing and performs the cleaning process,
Pump control means for causing the ink to be fed to the ink head by the liquid feed pump after the ink is sucked by the suction pump in the cleaning process, and for causing the inside of the inkjet nozzle to have a pressure higher than atmospheric pressure. Inkjet printer characterized by. The inkjet printer according to claim 1, wherein
The pressure above the atmospheric pressure is 0 to 1 kPa (G). The inkjet printer according to claim 1 or 2,
An ink jet printer, wherein the different types of inks are inks having different colors. An ink head formed with a plurality of inkjet nozzles for discharging different types of ink;
A liquid feed pump for feeding the ink to the ink head;
A cap member for sealing the opening of the inkjet nozzle;
A suction pump for sucking the ink from the inkjet nozzle;
A method for cleaning an ink head in an ink jet printer, comprising: a wiper device that cleans an ink jet nozzle surface in which an opening of the ink jet nozzle is located with a wiper blade.
In the ink jet printer cleaning method of performing the cleaning process by releasing the sealing of the opening by the cap member after the ink is sucked from the ink jet nozzle by the suction pump.
After the ink is sucked by the suction pump in the cleaning process, the ink is fed to the ink head by the liquid feeding pump, and the pressure inside the ink jet nozzle is set to a pressure higher than atmospheric pressure. Ink head cleaning method. The method of cleaning an ink head in an ink jet printer according to claim 4,
The pressure above the atmospheric pressure is 0 to 1 kPa (G). A method of cleaning an ink head in an ink jet printer. The method for cleaning an ink head in an ink jet printer according to claim 4,
The method of cleaning an ink head in an ink jet printer, wherein the different types of ink are inks having different colors.

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