JP5162209B2 - Inkjet printing apparatus and program for cleaning print head - Google Patents

Description

  The present invention relates to an inkjet printing apparatus, a print head cleaning method program, and a print head cleaning method, and more particularly, to an inkjet printing apparatus that wet wipes a print head, a print head leaning method program, and a print head cleaning method.

  There is an ink jet printing apparatus that performs printing while reciprocating a carriage on which a print head is mounted. In general, the ink jet printing apparatus ejects ink while scanning a print head having a plurality of nozzles for ejecting ink in a line direction orthogonal to the paper feeding direction, and performs printing while intermittently feeding the paper. It is configured.

  By the way, when cleaning the print head of an inkjet printing apparatus, if the print head is wiped with a wipe blade containing a cleaning liquid, ink droplets attached to the nozzle plate of the print head are effectively removed. It is known that it can be removed.

By the way, when performing the wet wipe as in Patent Document 1, the wiper blade wipes the Nols plate. For this reason, ink, cleaning liquid and air are pushed into the nozzle, and it is troublesome to remove this well. Met.
JP 2007-50590 A

  As described above, when performing wet wipe of the print head, the nozzle plate is wiped with a wipe blade, but for this reason, ink, cleaning liquid and air are pushed into the nozzle, and this can be successfully removed. It was quite difficult.

  Therefore, there is a demand for an ink jet printing apparatus that can remove ink, cleaning liquid, and air in the nozzle after cleaning with wet wipes, and can finish so that ink droplets, cleaning liquid, and dry mist do not remain on the nozzle plate. It was. That is, it has been desired to improve the cleaning property, ensure the printing stability, and improve the maintenance property when wiping the print head with a wiping blade having high ink detergency.

  The present invention has been made in view of such circumstances, and an object of the present invention is to effectively remove ink, cleaning liquid, and air that are pushed into a nozzle during wet wipe, and after cleaning, a nozzle plate An ink jet printing apparatus and a print head cleaning method that can be finished so that no ink droplets or the like remain on the surface, can improve the cleaning property and the printing stability, and can recover the meniscus of the nozzle. It is to provide a program and a print head cleaning method.

The present invention has been made to solve the above problems, and an ink jet printing apparatus according to the present invention includes a print head having nozzles for ejecting ink, and a carriage on which the print head is mounted is orthogonal to the paper transport direction. performs printing ink while scanning direction by causing dot jetting, the print head an ink jet printing apparatus that forms a meniscus in said nozzle of the print head after cleaning by wet wipes, nozzles of the print head and wet wiping unit for wet wipes by wiping blade on the surface of the plate using a washing liquid, mounted on said printed on the carriage and wet wipes the home position and the wet wipe unit is a cleaning position of the print head Key to move the head A ridge controller, and a cap of concave shape to form a cap space between said nozzle plate at the home position to the surface of the nozzle plate of the print head is brought into close contact with the peripheral edge portion of the print head, the applying a cap controller for separating adhesion or the peripheral end portion of the cap to the nozzle plate, the negative pressure in the cap space, the ink from the nozzle, the nozzle plate and the cap space, air, wherein a suction pump for sucking the cleaning liquid and mixtures thereof, oN of the suction pump, OFF, and and the suction pump control unit that controls the suction force of the suction pump, in the cap space, the external air upon opening An atmosphere release valve to be circulated, an atmosphere release valve control unit for controlling opening and closing of the atmosphere release valve, and the printing head. A head driving unit for a driven at a desired frequency to eject ink droplets of a desired number, the after performing the cleaning of the print head sends a command signal to the control unit, the said nozzles of said print head provided with a print head cleaning control unit for forming a meniscus, the print head cleaning control unit, the print head is moved to the wet wipe position by the carriage control unit, on the surface of the nozzle plate of the print head a wiping controller for the wet wipe by moving the wipe blade, wherein after the wet wipe of the printhead by wiping controller, moving the print head to the home position by the carriage control unit, and the cap the control unit forms the cap space The state, the closing the atmosphere release valve by the air release valve controller, the ink pushed into the nozzle during the wet wipe, the air, in order to eliminate the washing liquid and the mixed solution thereof A small amount suction control unit in the cap that controls the suction pump by the suction pump control unit so that the required predetermined negative pressure is applied to the cap space for a predetermined time in a short time and a high negative pressure; the ink according to trace suction control section, the air, after suction of the cleaning liquid and their said mixture, said print head by said head driver in order to form the meniscus on the nozzle of the print head at a desired frequency A spit control unit that is driven to eject a desired number of ink droplets. The ridge controller is controlled to move the print head to the home position, the cap controller is controlled to bring the peripheral end into close contact with the nozzle plate, and the atmosphere release valve controller is controlled to control the atmosphere. closing the open valve, the control suction pump control unit is rotated at a high speed the suction pump, by applying negative pressure for a predetermined time in the cap space sucking the ink from the nozzle, the said peripheral edge nozzle The negative pressure in the cap space is reduced by allowing the first standby time to elapse while being in close contact with the plate, and the air release valve control unit is controlled while the peripheral end portion is in close contact with the nozzle plate to An open valve is opened, the suction pump control unit is controlled to rotate the suction pump at a lower speed slower than the high speed rotation to discharge the ink in the cap, and Controls the loop control unit releases the nozzle plate from the peripheral end portion, the controls the wiping controller the nozzle plate and the wet wipes, the peripheral edge portion by controlling the cap trace suction control unit The suction pump is rotated at a preset speed while being in close contact with the nozzle plate , and a high negative pressure is applied to the cap space in a short time, so that the peripheral end portion is in close contact with the nozzle plate. The negative pressure in the cap space is reduced by allowing the second waiting time to elapse, and the atmospheric release valve control unit is controlled to open the atmospheric release valve while keeping the peripheral end in close contact with the nozzle plate. The suction pump control unit is controlled so that the peripheral end portion is in close contact with the nozzle plate so that the suction pump does not vibrate the ink in the nozzle. The ink in the cap is discharged at a slower speed than the low-speed rotation, and the spit controller is controlled to discharge a predetermined number of ink droplets from the print head while keeping the peripheral edge in close contact with the nozzle plate . It is characterized by that.

  In the inkjet printing apparatus of the present invention having the above configuration, after wiping so that ink droplets and the like do not remain on the nozzle plate by wet wiping, the print head is moved to the home position and pushed into the nozzle by the wet wiping. Ink, air, cleaning liquid and a mixture thereof are sucked into the cap space, and then the ink and the like in the cap space are sucked and discarded. Furthermore, a meniscus in the nozzle is formed at the end of cleaning.

  Thereby, in the inkjet printing apparatus equipped with the wet wipe unit, it is possible to improve the cleaning stability and the printing stability. Further, the meniscus of the nozzle can be recovered. Therefore, wet wiping can be performed effectively, and the maintainability is improved.

  In the inkjet printing apparatus of the present invention, the wiping control unit is configured to determine the moving speed of the wipe blade and the number of wiping operations based on parameters including ink viscosity, ink temperature, or ambient environment temperature. It is characterized by that.

  In the ink jet printing apparatus of the present invention configured as described above, the wiping speed of the wiping blade and the number of wiping operations are determined based on parameters including ink viscosity, ink temperature, or ambient environment temperature.

  As a result, the optimum wet wipe can always be performed, and the stability of the cleaning can be improved.

  In the ink jet printing apparatus of the present invention, the spit control unit lowers the driving frequency of the piezoelectric element in the print head to be lower than the head driving frequency during printing when the meniscus is formed.

  In the inkjet printing apparatus of the present invention having the above-described configuration, the drive frequency of the piezoelectric element in the print head is set lower than the drive frequency of the print head during printing when the meniscus is formed after cleaning. For example, the frequency is about 10 kHz during normal printing, and about 5 kHz during meniscus formation.

  Thereby, a meniscus can be appropriately formed without causing ink mist in the cap space.

The program of the cleaning method of the print head of the present invention comprises a print head having nozzles for ink ejection, a printing said ink while scanning in a direction perpendicular to the print head to the sheet conveying direction by causing dot injection An inkjet printing apparatus that performs a wet wipe unit that wipes the surface of the nozzle plate of the print head with a wipe blade using a cleaning liquid, a home position that is a cleaning position of the print head, and the wet wipe unit. A carriage that moves the print head to a wet wipe position, and a concave cap for forming a cap space between the nozzle plate and a peripheral end in close contact with a surface of the nozzle plate at the home position; Negative in the cap space Was applied, comprises the ink from the cap space, and a suction pump for sucking air, the washing liquid and mixtures thereof, the cap space, and a air release valve for circulating the external air upon opening A program for cleaning a print head in an inkjet printing apparatus, comprising: a control procedure for moving the print head to the home position by a computer in the inkjet printing apparatus; and a control for bringing the peripheral edge into close contact with the nozzle plate and procedures, to close the air release valve, the suction pump is rotated at a high speed, a control procedure for sucking the ink from the nozzle a negative pressure in the cap space by applying a predetermined time, the nozzle plate the peripheral edge The negative pressure in the cap space is reduced by allowing the first waiting time to elapse while being in close contact with A control procedure for reducing the pressure, a control procedure for opening the atmosphere release valve while keeping the peripheral end in close contact with the nozzle plate, and rotating the suction pump at a lower speed slower than the high speed rotation. a control procedure for discharging ink, the control procedure of separating the nozzle plate from the peripheral edge portion, in a state of moving the print head to the wet wipe position by the carriage, on the surface of the nozzle plate of the print head wiping control procedure of the wet wipe by moving the wipe blade in, after the wet wipe of the print head by the wiping control procedure, moving the print head to the home position by the carriage, and by the cap In the state where the cap space is formed, the atmosphere is opened. Closes the Houben, the ink pushed into the nozzle during the wet wipe, the air, rotated at pre Me set speed in order to eliminate the washing liquid and the mixed solution thereof wherein wherein the cap trace suction control procedure for controlling the suction pump, the ink by the cap trace suction control procedure, the air, the cleaning solution and the mixing thereof to apply a short time and high negative pressure in the cap space After suction of the liquid, a control procedure for reducing the negative pressure in the cap space by allowing the second waiting time to elapse while keeping the peripheral end in close contact with the nozzle plate, and the peripheral end in close contact with the nozzle plate the nozzle and the control procedure, the suction pump while the peripheral edge is brought into close contact with the nozzle plate to the air release valve while it is in the open state The nozzle of the control procedure for discharging the ink in the cap the ink is slow rotated from the low speed so as not to vibrate, the peripheral end portion of the print head while it is in close contact with the nozzle plate a spit control procedure drives the print head to eject a predetermined number of ink droplets to form the meniscus is characterized by being performed in.

  A print head cleaning method according to the present invention including the above-described procedure is executed by a computer in the inkjet printing apparatus so that the ink head is wet wiped so that no ink droplets or the like remain on the nozzle plate, and then the print head Is moved to the home position, and the liquid mixture and air of the cleaning liquid and ink pushed into the nozzle by the wet wipe are sucked into the cap space, and then the ink in the cap space is sucked and discarded. Furthermore, a meniscus in the nozzle is formed at the end of cleaning.

  Thereby, in the inkjet printing apparatus equipped with the wet wipe unit, it is possible to improve the cleaning stability and the printing stability. Further, the meniscus of the nozzle can be recovered. Therefore, wet wiping can be performed effectively, and the maintainability is improved.

  In the print head cleaning method of the present invention including the above-described procedure, the print head is moved to the home position by the first wiping process after the wet wiping process so that no ink droplets or the like remain on the nozzle plate. In the cap space, the cleaning liquid and ink mixture liquid and air pushed into the nozzle by the wet wipe are sucked into the cap space, and then the ink in the cap space is sucked and discarded in the second suction process. To do. Further, the meniscus in the nozzle is formed at the end of cleaning by the process of forming the meniscus on the nozzle.

  Thereby, in the inkjet printing apparatus equipped with the wet wipe unit, it is possible to improve the cleaning stability and the printing stability. Further, the meniscus of the nozzle can be recovered. Therefore, wet wiping can be performed effectively, and the maintainability is improved.

  Further, in the inkjet printing apparatus of the present invention, it is possible to mount a wet wipe unit that performs wet wipe, thereby improving the cleaning property and the printing stability. In addition, maintainability is improved and the number of head cleanings can be reduced, so that the amount of waste ink can be reduced.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, a schematic configuration of the entire inkjet printing apparatus of the present invention will be described.
FIG. 3 is a diagram illustrating a configuration example of an inkjet printing apparatus including a wet wipe mechanism. The ink jet printing apparatus shown in FIG. 3 is an example of a business-use ink jet printing apparatus for 6-color printing in a wide format with a long print width, for example, 50 inches or more.

  In the ink jet printing apparatus shown in FIG. 3, the print head 21 is in a standby position, that is, a home position. The print head 21 includes color heads 21 a corresponding to the six colors of ink, and ink is supplied to the print head 21 from the ink cartridge 25 through the ink tube 26. The print head 21 is cooled by a head cooling fan 29.

  A cap and a suction pump 35 are provided corresponding to each color head 21 a of each color of the print head 21, and waste ink sucked by the suction pump 35 is stored in a waste liquid tank 37.

  The print head 21 is mounted on the carriage 28, driven by a motor 52, and driven in the direction of arrow A along the carriage reel 51. Further, the print head 21 is moved to the position of the wet wipe unit 41 to wipe off ink liquid, dry mist, and the like remaining on the nozzle plate of the print head 21.

  In this wet wipe unit 41, a rubber wipe blade 42 abuts against the nozzle plate of the print head 21, and the wipe blade 42 is driven to rotate in a plane perpendicular to the paper surface in the drawing to wipe off the ink liquid. It is configured.

  A pinch roller 54 that is rotationally driven by a motor 56 is a roller for feeding a print sheet, and the print sheet is nipped and conveyed by the pinch roller 54 and the grid roller 55. Printing is performed by ejecting ink from the print head 21 while moving the carriage 28 in the direction of arrow A on the printing paper on the platen 53.

  FIG. 4 is a diagram illustrating a configuration example of the print head and the cap unit. The example shown in FIG. 4 shows a state where the print head 21 is located at the home position, and shows an example of a cap unit corresponding to one color in the print head 21. As shown in FIG. 4, the print head 21 includes a plurality of nozzles 22 for one color arranged in the main scanning direction and a nozzle plate 23.

  The cap unit includes a flexible cap 31 made of rubber or the like having a concave peripheral end portion 31a formed around the cap unit, and moves in the direction of arrow A to adhere to the nozzle plate 23. The cap 31 includes a tube 32 that communicates with the suction pump 35 and a tube 33 that communicates with the air release valve 34.

  When cleaning the print head 21, the peripheral end portion 31 a around the cap 31 is brought into close contact with the nozzle plate 23. Thereby, a cap space 31b which is a closed space formed by the cap 31 and the nozzle plate 23 is formed. The suction pump 35 is driven by the motor 36 with the atmosphere release valve 34 closed. Thereby, a negative pressure is applied in the cap space 31b, and the ink, air, cleaning liquid, and the like pushed into the nozzle 22 are sucked, and ink, a cleaning agent, and the like in the cap space 31b are sucked.

  The sucked ink or the like is stored in the waste liquid tank 37 through the tube 32 and the suction pump 35. The suction pump motor control device 38 is a motor control device for controlling the start, stop, and rotation speed of the motor 36. In addition, a wet wipe unit 41 including a wipe blade 42 is disposed at a position different from the cap 31. The print head 21 moves between the wet wipe unit 41 and the cap 31 by moving the carriage, and maintenance is performed at each location.

  Next, a configuration example of the print head cleaning control unit in the inkjet printing apparatus of the present invention will be described.

  FIG. 1 is a diagram illustrating a configuration example of an ink jet printing apparatus according to an embodiment of the present invention. The example shown in FIG. 1 shows only the portions directly related to the present invention, and the portions not directly related to the present invention such as a print image generation unit, a paper feed mechanism and a control unit of the print paper are omitted. Show.

  In FIG. 1, a print head cleaning control unit 1 is composed of a computer system including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory) and the like, and can be used in the ink jet printing apparatus of the present invention. A control unit that supervises print head cleaning control processing. The print head cleaning control unit 1 includes a wiping control unit 2, a suction pump control unit 4, an air release valve control unit 5, a cap control unit 6, an ink suction control unit 7, a spit control unit 14, a carriage And a control unit 15.

  A program is stored in the ROM, and in accordance with the program, the RAM is used as a primary storage and work area, and the CPU calculates and executes various processes. The print head cleaning control unit 1 can also be configured by an electronic circuit.

  In a state where the print head 21 is moved to the position of the wet wipe unit 41, the wiping control unit 2 presses the wipe blade 42 with the cleaning agent against the nozzle plate 23 of the print head 21, and moves the wipe blade 42. Thus, control for wiping off the surface of the nozzle plate 23 is performed.

  The wiping control unit 2 sends a command signal to the wipe motor control device 44, rotationally drives the motor 43 by the wipe motor control device 44, and moves the wipe blade 42 connected to the motor 43 by a gear or the like.

  The wiping control unit 2 includes a table 3 that associates ink temperature or ambient environment temperature, ink viscosity, wiping speed that is the moving speed of the wiping blade 42, and the number of wiping operations. The wiping control unit 2 controls the moving speed of the wiping blade 42 and the number of wiping operations with reference to the table 3 based on the ink temperature or ambient environment temperature information received from the temperature sensor 45. The table 3 is experimentally determined according to the shape of the head and the structure of the wiping mechanism, using the ink viscosity, the ink temperature, the ambient environment temperature, or the like as parameters.

  The suction pump control unit 4 receives a command signal such as a rotational speed, an ON / OFF command from the ink suction control unit 7, and sends a control command signal to the suction pump motor control device 38 based on the command signal. The suction pump motor control device 38 controls the rotation speed of the motor 36 according to the control command signal received from the suction pump control unit 4, and drives the suction pump 35 by the rotation of the motor 36. The suction pump control unit 4 controls the suction force of the suction pump 35 based on the number of rotations of the motor 36 based on a value corresponding to a preset condition. As another example of changing the suction force, it can be changed by switching pumps of different sizes or switching the number of pumps.

  The atmosphere release valve control unit 5 receives a command signal for opening and closing the atmosphere release valve from the ink suction control unit 7, and sends a control command signal to the atmosphere release valve drive unit 40 based on this command signal. The atmosphere release valve drive unit 40 is constituted by, for example, a solenoid, and opens and closes the atmosphere release valve 34 according to a control command signal received from the atmosphere release valve control unit 5. The atmosphere release valve 34 is moved in the direction of arrow B in the figure.

  The cap control unit 6 receives a command signal from the ink suction control unit 7 and sends a control command signal to the cap drive unit 39 based on the command signal. The cap drive unit 39 is configured by, for example, a solenoid, and moves the cap 31 in the direction of arrow A in accordance with a control command signal received from the cap control unit 6, so that the peripheral end 31 a of the cap is in close contact with the nozzle plate 23. Control whether to separate. When the cap 31 is brought into close contact with the nozzle plate 23, the nozzle plate 23 is covered with the cap 31, and a cap space 31 b is formed by the nozzle plate 23 and the cap 31.

  The carriage control unit 15 receives a movement command signal for the carriage 28 from the print head cleaning control unit 1 and causes the carriage 28 to travel based on the command signal.

  The ink suction control unit 7 includes an in-nozzle ink suction control unit 8, a first standby time control unit 9, an in-cap ink suction control unit 10, an in-cap minute amount suction control unit 11, and a second standby time. A control unit 12 and an after-suction ink suction control unit 13 are provided. Note that each processing unit in the ink suction control unit 7 is a processing unit that sequentially performs processing in accordance with the progress of the cleaning process. Therefore, in accordance with the description of the cleaning process in the inkjet printing apparatus of the present invention, Each processing unit in the suction control unit 7 will be described.

  With the above configuration, the print head cleaning control unit 1 controls each processing unit to execute a cleaning process and a meniscus forming process.

  In this case, the print head cleaning control unit 1 controls the carriage control unit 15 to move the print head 21 to the home position, detects that the print head 21 is at the home position, and the cap control unit 6 causes the cap space 31b. After forming the cleaning process, the cleaning process is started.

  The ink suction control unit 7 first controls the air release valve 34 and the suction pump 35 to apply a negative pressure to the cap 31 and perform suction processing in response to a cleaning start command signal from the print head cleaning control unit 1. Do. In this step, the in-nozzle ink suction control unit 8 in the ink suction control unit 7 sends a command signal for closing the atmosphere release valve 34 to the atmosphere release valve control unit 5 to close the atmosphere release valve 34. The in-nozzle ink suction control unit 8 turns on the suction pump 35 and sends a command signal for rotating the suction pump 35 at a high speed to the suction pump control unit 4 in a state where the air release valve 34 is closed. As described above, the ink suction control unit 8 in the nozzle controls the suction pump 35 so as to suck the ink, air, and the mixed liquid thereof in the nozzle 22 of the print head 21, thereby negative pressure in the cap space 31 b. Is applied for a predetermined time. In this case, since a large amount of ink is sucked, the suction pump 35 is rotated at a high speed.

  Subsequent to the above-described step of sucking ink, air, and the like from the nozzle 22 by the ink suction control unit 8 in the nozzle, the print head cleaning control unit 1 controls the ink suction control unit 7 to perform a first waiting time step. Execute. In the first waiting time step, a step of waiting for a predetermined time in a state where the air release valve 34 is closed and the suction pump 35 is stopped is executed.

  In this standby process, the first standby time control unit 9 in the ink suction control unit 7 counts a predetermined time and instructs the atmospheric release valve control unit 5 to close the atmospheric release valve 34 during this predetermined time. A signal is sent and the atmosphere release valve 34 is closed. The first standby time control unit 9 sends a command signal for turning off the suction pump 35 to the suction pump control unit 4 to turn off the suction pump 35.

  In this way, after the ink suction control unit 8 in the nozzle completes the suction of ink or the like, a process of waiting for a predetermined time is performed while the air release valve 34 is closed and the suction pump 35 is stopped. During this waiting time, the negative pressure in the cap space 31b is made as much as possible to prevent air from being mixed when the air release valve 34 is opened.

  Subsequent to the standby process by the first standby time control unit 9 described above, the print head cleaning control unit 1 controls the ink suction control unit 7 to suck the ink sucked from the nozzles 22 and staying in the cap space 31b.・ Execute the disposal process.

  In the step of sucking and discarding the ink or the like staying in the cap, the ink suction control unit 10 in the ink suction control unit 7 sends a command signal to the atmosphere release valve control unit 5 to open the atmosphere release valve 34. The air release valve 34 is opened. Further, the in-cap ink suction control unit 10 sends a command signal for turning on the suction pump 35 to the suction pump control unit 4 to turn on the suction pump 35 for a predetermined time. As described above, the ink suction control unit 10 in the cap opens the air release valve 34 after the standby time by the first standby time control unit 9 elapses, and controls the suction pump 35 to suck ink or the like in the cap. To dispose of it. Note that suctioning with the air release valve 34 opened is also referred to as “empty suction”. In this empty suction, the ink or the like accumulated in the cap is discarded, and the suction pump 35 is rotated at a low speed in order to suck ink while preventing the ink from scattering. For example, the rotation speed is lower than the rotation speed of the suction pump driven by the ink suction control unit 8 in the nozzle.

  Then, the print head cleaning control unit 1 controls to pull the cap 31 away from the nozzle plate 23 while the suction pump 35 is OFF and the air release valve 34 is open, thereby releasing the cap space 31b.

  Subsequent to the above-described suction process by the in-cap ink suction control unit 10, the print head cleaning control unit 1 controls the carriage control unit 15 to move the print head 21 to the position of the wet wipe unit 41. In this state, the print head cleaning control unit 1 controls the wiping control unit 2 to perform the wet wipe of the print head 21. After the wet wipe, the print head cleaning control unit 1 controls the carriage control unit 15 to move the print head 21 to the home position. Further, the print head cleaning control unit 1 controls the cap 31 to be in close contact with the nozzle plate 23 to form a cap space 31b.

  After the above-described wet wiping process by the wiping control unit 2, the print head cleaning control unit 1 controls the ink suction control unit 7, and the ink and air pushed into the nozzle 22 by the wipe blade 42 during the wet wiping. In order to eliminate the cleaning liquid and the mixed liquid thereof, a step of applying a necessary negative pressure to the cap space 31b for a required time and sucking a small amount of ink, air, cleaning liquid and the like is executed.

  In this trace suction step, the in-cap trace suction controller 11 in the ink suction controller 7 sends a command signal for closing the atmosphere release valve 34 to the atmosphere release valve controller 5 to close the atmosphere release valve 34. . Further, the in-cap trace suction control unit 11 sends a command signal for turning on the suction pump 35 for a short time to the suction pump control unit 4 in a state where the air release valve 34 is closed. In this way, the in-cap micro-aspiration control unit 11 eliminates the ink, air, cleaning liquid and mixed liquid thereof pushed into the nozzle 22 by the wipe blade 42 during the wet wipe, only for a necessary time. A process of applying a necessary negative pressure into the cap space 31b is performed. This micro-aspiration is, for example, a very short time of 0.2 seconds and a high negative pressure. This minute suction is performed to suck ink, air, cleaning liquid, etc. pushed into the nozzle. At this time, the ink liquid accumulated in the cap contacts the nozzle plate between the cap sheet and the nozzle plate. A small amount of ink is sucked to prevent ink columns from being generated. If ink columns are formed, there is no possibility that ink drops will not remain on the nozzle plate even if the subsequent empty suction is devised.

  In addition, the amount of suction by the in-nozzle ink suction control unit 8 is such that at least the amount of ink staying in the print head 21 is exchanged in order to remove dust and air in the nozzle 22. The nozzle plate 23 may be immersed in the ink that has entered the cap space 31b. However, the amount to be sucked by the in-cap minute amount suction control unit 11 removes the pushed object, so that it is not necessary to replace all the ink staying in the print head 21. Further, it is necessary that the ink is stored in the cap space 31b and the suction is performed so that the nozzle plate 23 is not immersed by the stored ink. Therefore, it is preferable to set the suction amount by the in-cap minute amount suction control unit 11 to be smaller than the suction amount by the ink suction control unit 8 in the nozzle.

  Subsequent to the above-described minute suction step, the print head cleaning control unit 1 controls the ink suction control unit 7 to execute the second standby time step. In the second waiting time step, a step of waiting for a predetermined time in a state where the air release valve 34 is closed and the suction pump 35 is stopped is executed.

  In this standby process, the second standby time control unit 9 in the ink suction control unit 7 counts a predetermined time and instructs the atmospheric release valve control unit 5 to close the atmospheric release valve 34 during this predetermined time. A signal is sent and the atmosphere release valve 34 is closed. The second standby time control unit 9 sends a command signal for turning off the suction pump 35 to the suction pump control unit 4 to turn off the suction pump 35. In this way, after completion of ink suction by the in-cap micro-suction control unit 11, a process of waiting for a predetermined time is performed while the air release valve 34 is closed and the suction pump 35 is stopped. During this waiting time, the negative pressure in the cap space 31b is made as much as possible to prevent air from being mixed when the air release valve 34 is opened.

  Following the standby process by the second standby time control unit 9 described above, the print head cleaning control unit 1 controls the ink suction control unit 7 so that a small amount of ink is sucked from the nozzles 22 and stays in the cap space 31b. The process of sucking and discarding etc. is executed.

  In the step of sucking and discarding the ink staying in the cap after the minute suction, the ink suction control unit 13 after the minute suction in the ink suction control unit 7 opens the atmosphere release valve 34 in the atmosphere release valve control unit 5. A command signal is sent to open the atmosphere release valve 34. Further, the ink suction control unit 13 after micro-suction sends a command signal for turning on the suction pump 35 to the suction pump control unit 4 to turn on the suction pump 35 for a predetermined time. As described above, the ink suction control unit 13 after micro-suction accumulates in the cap space 31b after the second waiting time has elapsed after the micro-suction by the micro-suction control unit 11 in the cap and the air release valve 34 is opened. A process of sucking and discarding the ink etc. that is being discharged is performed. In this empty suction, the suction pump 35 is operated at a low speed in order not to scatter the ink, but also to prevent the ink in the nozzle 22 from being affected by vibration or the like and to discard the ink and the like accumulated in the cap. Rotate. For example, the rotation speed is lower than the rotation speed of the suction pump driven by the ink suction controller 10 in the cap.

  The amount of ink and cleaning liquid that is pushed in varies depending on the number of nozzles, and the appropriate suction force and number of times vary depending on the capacity of the cap space 31b and changes in ink characteristics depending on the environment. Further, as a further improved example, these conditions are obtained in advance by experiments, and the suction force and the number of times required for the minute suction and the empty suction can be implemented according to these conditions. As a result, it is possible to completely eliminate ink, cleaning liquid and the like pushed into the nozzle.

  The cleaning step is completed by performing the idle suction by the ink suction control unit 13 after the minute suction described above.

  Thereafter, the print head cleaning control unit 1 sends a command signal for forming a meniscus to the nozzle 22 to the spit control unit 14, and the spit control unit 14 sends a print drive 21 to the head drive unit 24 at a desired drive frequency. A control command signal for ejecting a desired number of ink droplets is transmitted. The head drive unit 24 drives the print head 21 in accordance with the control command signal received from the spit control unit 14 to eject ink droplets. Thereby, a meniscus is formed in the nozzle 22 of the print head.

  In this way, the head 21 is cleaned to form a meniscus by completely removing air and dust in the ink flow path and forming a well-formed meniscus, thereby enabling long-time printing. Become.

  In forming the meniscus, “head driving frequency during printing <head driving frequency during spit” is set. For example, if the head drive frequency during printing is 10 kHz, the head drive frequency during spit is preferably about 5 kHz.

  Further, the number of ink droplets to be ejected is larger in the case of the wet wipe of the present invention than the number of ink droplets in a spit that is formed when a meniscus is formed after cleaning without dry wiping or wiping. For example, in the case of dry wipe, several hundreds of ink droplets are ejected, whereas in the case of the wet wipe of the present invention, it is preferable that the number is 10 times or more, for example, 6000 or more. Note that if the number exceeds a predetermined number, for example, if the number of shots is 10,000 or more, the nozzle plate becomes dirty due to mist flying in the cap space 31b.

  With the above-described configuration of the inkjet printing apparatus of the present invention, the nozzle plate of the print head is wet wiped, and the ink, air, cleaning liquid, and the like pushed into the nozzle by the wet wipe are discharged to perform cleaning and prepare the meniscus. To.

  Thereby, in the inkjet printing apparatus of the present invention, the wet wipe unit can be mounted and the print head can be effectively cleaned, so that the cleaning property can be improved. This is because the ink easily adheres to the nozzle plate in the case of dry wipe, and the ink may dry and harden. Once solidified, it cannot be removed by dry wipe, but can be removed in the case of wet wipe. Thus, since the nozzle plate can be cleaned cleanly, the number of head cleanings can be reduced, and the amount of ink waste liquid can be reduced.

  Further, it becomes possible to mount a wet wipe unit, and the nozzle plate and the nozzle are difficult to dry, so that the printing stability is improved. Further, since the nozzle plate is moist, capping defects are reduced, and the cleaning property can be improved.

  FIG. 2 is a sequence diagram showing a print head cleaning process in the ink jet printing apparatus of the present invention. Hereinafter, the processing steps will be described with reference to the sequence diagram of FIG.

(Step of sucking ink and air from inside the nozzle)
First, air and dust are sucked from the nozzle. For this purpose, the print head 21 is moved to the home position, and the cap 31 is closed. That is, the peripheral end portion 31a of the cap 31 is brought into contact with the nozzle plate 23, and the cap 31 is placed on the nozzle plate 23 of the print head 21 to form the cap space 31b (step S1).

  Next, the ink release controller 8 in the nozzle closes the air release valve (step S2), turns on the suction pump, and sucks ink and air from the nozzle (step S3). In this case, since a large amount of ink is sucked, the pump is rotated quickly.

  After that, the first standby time control unit 9 turns off the suction pump 35 (step S4), provides a first standby time, and reduces negative pressure to prevent air from being mixed when the atmospheric release valve 34 is opened. (Step S5).

(Suction / disposal of ink in the cap space)
Subsequently, the ink in the cap 31 sucks and discards the ink existing in the cap space 31b.

  In this case, the air release valve 34 is opened (step S6), the suction pump 35 is turned on (step S7), and ink (including air bubbles) existing in the cap space is sucked and discarded. Thereafter, the suction pump 35 is turned off (step S8), the air release valve 34 is kept open (step S9), and the cap 31 is opened (step S10).

(Process to execute wiping)
Subsequently, the wipe control unit 2 executes wet wipe. In this case, the print head 21 is moved to the position of the wet wipe unit 41 (step S11), and wet wipe is performed (step S12).

  In this wet wipe, finishing is performed so that ink droplets and cleaning droplets do not remain on the nozzle plate 23. This is the final finished state. In this wet wipe, if the wiping speed is not set to an appropriate value on the basis of the viscosity of the ink and the water repellency of the nozzle plate, the wet wipe cannot be cleaned many times.

  Therefore, the wiping speed is determined using the ink viscosity, the ink temperature, the ambient environment temperature, or the like as parameters. For example, it is determined experimentally according to the shape of the head and the structure of the wiping mechanism, and a table having parameters such as ink viscosity, ink temperature, or ambient environment temperature is provided. The number of wet wipes is also determined based on parameters such as the model, ink viscosity, ink temperature, or ambient environment temperature.

(Small amount suction process)
When the wet wipe is completed, the print head 21 is moved to the cap unit (step S13), and the cap 31 is closed (step S14).

  Then, the atmosphere opening valve 34 is closed by the in-cap microsuction control unit 11 (step S15), the suction pump 35 is turned on, and microsuction is performed from the cap space 31b (step S16). This micro-aspiration is, for example, a very short time of 0.2 seconds and a high negative pressure.

  This minute suction is performed to suck the air, cleaning liquid, and the like pushed into the nozzle 22 by the wet wipe, and at this time, in order to prevent an ink column from being formed between the cap sheet and the nozzle plate. Aspirate a small amount. If ink columns are formed, there is no possibility that ink drops will not remain on the nozzle plate even if the subsequent empty suction is devised.

(Suction / disposal process of ink liquid after micro suction)
After a minute amount of suction, the second standby time control unit 12 turns off the suction pump (step S17) and enters a standby state (step S18). In this standby state, negative pressure is eliminated as much as possible in order to prevent air from entering when the air release valve is opened.

  Thereafter, the air suction valve 34 is opened by the ink suction control unit 13 after a small amount of suction (step S19), and the suction pump 35 is turned on and empty suction is performed (step S20). In this empty suction, the suction pump 35 is rotated at a low speed in order to discard the ink accumulated in the cap space 31b. For example, the rotational speed is set lower than that in step S7.

  Furthermore, the amount of the ink that is pushed into the nozzles and the amount of the cleaning liquid that is pushed into the nozzles when wet wiping is interrelated with the capacity of the cap space 31b. There are cases where ink or cleaning liquid that has been satisfactorily pushed in by suction cannot be fully discharged. The required suction force and the number of times of suction are obtained by experiments according to the environment and use conditions to be sucked in advance, and the suction force and the number of suctions are controlled according to the environment and use conditions. The number of suctions can be controlled by repeating steps 16 to 20 for a necessary number of times determined in advance.

(Spit process)
Subsequently, a spit is performed by the spit control unit 14 (step S21). In this spit, the print head 21 is driven to eject ink droplets so that the shape (meniscus) of the ink liquid surface at the outlet of the nozzle 22 is uniform at each nozzle 22. Therefore, a meniscus is formed by ejecting ink droplets at a lower drive frequency for ejecting ink droplets. In this case, the head drive frequency is “frequency during printing <frequency during meniscus formation”. When the frequency is 10 kHz or more during printing, it is preferably 5 kHz or less during meniscus formation. Further, the number of ink droplets at the time of meniscus formation is larger than that in the case of dry wipe. For example, if the number of dry wipes is several hundred, the number of wet wipes is several thousand, which is about ten times that. On the other hand, if the amount is too large, the nozzle plate becomes dirty due to mist in the cap space.

  The head wiping, cleaning, and meniscus formation are performed by the processes from step S1 to step S21 described above, and the process ends (step S22).

  As described above, in the ink jet printing apparatus of the present invention, the wet wipe unit can be mounted and the print head can be effectively cleaned, so that the cleaning property can be improved. Further, since the maintenance labor can be reduced, the number of head cleanings can be reduced, and the amount of ink waste liquid can be reduced.

  Further, it becomes possible to mount a wet wipe unit, and the nozzle plate and the nozzle are difficult to dry, so that the printing stability is improved. Further, since the nozzle plate is moist, capping defects are reduced, and the cleaning property can be improved.

  Although the embodiments of the present invention have been described above, the ink jet printing apparatus of the present invention is not limited to the illustrated examples described above, and various modifications can be made without departing from the scope of the present invention. Of course.

It is a figure which shows the structural example of the inkjet printing apparatus concerning embodiment of this invention. It is a sequence diagram which shows the cleaning process of the print head in the inkjet printing apparatus of this invention. It is a figure which shows the example of an inkjet printing apparatus provided with a wet wipe unit. It is a figure which shows the structural example of a print head and a cap unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Print head cleaning control part 2 Wiping control part 3 Table 4 Suction pump control part 5 Atmospheric release valve control part 6 Cap control part 7 Ink suction control part 8 Ink suction control part 9 in nozzle 1 First waiting time control part 10 In cap Ink cap control unit 11 Intra-cap microsuction control unit 12 Second waiting time control unit 13 Ink suction control unit 14 after microsuction 14 Spit control unit 15 Carriage control unit 21 Print head 22 Nozzle 23 Nozzle plate 24 Head drive unit 25 Ink cartridge 26 Ink tube 28 Carriage 29 Head cooling fan 31 Cap 31a Circumferential end 31b Cap space 32, 33 Tube 34 Air release valve 35 Suction pump 36 Motor 37 Waste liquid tank 38 Suction pump motor controller 39 Cap drive unit 40 Air release valve drive unit 41 C Tsu DOO wiping unit 42 wipes the blade 43 motor 44 Waipumota controller 45 temperature sensor 46 motor

Claims (4)

A printing head having nozzles for ejecting ink is provided, printing is performed by ejecting dots of ink while scanning a carriage on which the printing head is mounted in a direction orthogonal to the paper transport direction, and the print head is cleaned by wet wipe. an inkjet printing device for forming a meniscus in said nozzle of the printing head after,
A wet wipe unit that wipes the surface of the nozzle plate of the print head with a wipe blade using a cleaning liquid;
A carriage controller for moving the print head mounted on the carriage and wet wipes the home position and the wet wipe unit is a cleaning position of said print head,
A cap concave shape to form a cap space between said nozzle plate at the home position to the surface of the nozzle plate of the print head is brought into close contact with the peripheral edge portion of the print head,
A cap controller for adhesion or separating the peripheral edge of the cap to the nozzle plate,
Wherein applying a negative pressure to the cap space, and the nozzle, the ink from the nozzle plate and the cap space, air, suction pump for sucking the cleaning liquid and mixtures thereof,
A suction pump control unit for controlling the ON of the suction pump, OFF, and the suction force of the suction pump,
In the cap space, an air release valve that circulates external air when opened,
An atmosphere release valve controller for controlling opening and closing of the atmosphere release valve;
A head drive unit that drives the print head at a desired frequency to eject a desired number of ink droplets;
Wherein after performing the cleaning of the print head sends a command signal to the control unit, and a print head cleaning controller for forming the meniscus to the nozzle of the print head,
With
The print head cleaning control unit
The print head is moved to the wet wipe position by the carriage control unit, and a wiping controller for the wet wipe by moving the wipe blade on the surface of the nozzle plate of the print head,
After the wet wipes of the print head by said wiping controller, wherein the carriage control unit moves the print head to the home position, and the state of forming the cap space by the cap control unit, the air release valve closing said air release valve by the control unit, the ink pushed into the nozzle during the wet wipe, the air, given a predetermined negative pressure required to eliminate the washing liquid and the mixed solution thereof A minute amount suction control unit in the cap that controls the suction pump by the suction pump control unit so as to apply a high negative pressure to the cap space in a short time for the time of ,
The ink according to the cap trace suction control section, the air, after suction of the cleaning liquid and their said mixture, optionally said print head by said head driver in order to form the meniscus on the nozzle of the print head A spit controller that is driven at a frequency of 5 to eject a desired number of ink droplets;
The print head cleaning control unit comprises:
Controlling the carriage control unit to move the print head to the home position;
Control the cap control unit to bring the peripheral end into close contact with the nozzle plate,
Closing said air release valve to control the air release valve controller, is rotated at high speed the suction pump by controlling the suction pump control unit, said from the nozzle a negative pressure in the cap space by applying a predetermined time Suck ink,
The negative pressure in the cap space is reduced by allowing the first waiting time to elapse while the peripheral edge portion is in close contact with the nozzle plate,
The atmosphere release valve is opened by controlling the atmosphere release valve controller while keeping the peripheral end in close contact with the nozzle plate,
Controlling the suction pump control unit to rotate the suction pump at a lower speed than the high speed rotation to discharge the ink in the cap;
Control the cap control unit to separate the nozzle plate from the peripheral end,
By controlling the wiping controller and the wet wipe the nozzle plate,
The suction pump is rotated at a preset speed while controlling the minute amount suction controller in the cap so that the peripheral end is in close contact with the nozzle plate , and a high negative pressure is generated in the cap space in a short time. Apply
Reducing the negative pressure in the cap space by allowing the second waiting time to elapse while keeping the peripheral end in close contact with the nozzle plate,
The atmosphere release valve is opened by controlling the atmosphere release valve controller while keeping the peripheral end in close contact with the nozzle plate,
The suction pump control unit is controlled while the peripheral end is in close contact with the nozzle plate, and the suction pump is rotated slower than the low-speed rotation so as not to vibrate the ink in the nozzle . Of the ink,
An inkjet printing apparatus, wherein the spit controller is controlled to eject a predetermined number of ink droplets from the print head while the peripheral edge is in close contact with the nozzle plate . The wiping control unit
The viscosity of the ink, based on parameters including ink temperature or ambient temperature, moving speed of the wiping blade, and configured it to determine the number of wiping,
The inkjet printing apparatus according to claim 1. The spit controller is
When forming the meniscus that, the driving frequency of the piezoelectric element in the print head, which is configured to be lower than the head drive frequency during printing,
The inkjet printing apparatus according to claim 1, wherein Comprising a print head having nozzles for ink ejection, an ink jet printing apparatus that performs printing the ink while scanning in a direction perpendicular to the print head to the sheet conveying direction by causing dot ejection, the nozzle plate of the print head A wet wipe unit that wipes the surface of the print head with a wipe blade using a cleaning blade, a carriage that moves the print head to a home position that is a cleaning position of the print head, and a wet wipe position of the wet wipe unit; A cap having a concave shape for forming a cap space between the nozzle plate and a peripheral end closely contacting the surface of the nozzle plate at the home position, and applying a negative pressure in the cap space, the cap space wherein the inner ink, air, the washing A suction pump for sucking the liquid and mixtures thereof, the cap space, a program of the method of cleaning the print head in the ink jet printing apparatus and a air release valve for circulating the external air when opened,
By a computer in the inkjet printing apparatus,
A control procedure for moving the print head to the home position;
A control procedure for bringing the peripheral end into close contact with the nozzle plate;
Closing said air release valve, a control procedure the suction pump is rotated at a high speed to suck the ink from the nozzle a negative pressure in the cap space by applying a predetermined time,
A control procedure for reducing the negative pressure in the cap space by allowing the first waiting time to pass while the peripheral edge portion is in close contact with the nozzle plate;
A control procedure for opening the atmosphere release valve while keeping the peripheral end in close contact with the nozzle plate;
A control procedure for discharging the ink in the cap by rotating the suction pump at a lower speed than the high speed rotation;
A control procedure for separating the nozzle plate from the peripheral end;
In the state of moving the print head to the wet wipe position by said carriage, and a wiping control procedure of the wet wipe by moving the wipe blade on the surface of the nozzle plate of the print head,
After the wet wipes of the print head by the wiping control procedure by the carriage to move the print head to the home position, and the state of forming the cap space by the cap, it closes the atmosphere release valve, the ink pushed into the nozzle during the wet wipe, the air, the washing liquid and and in a short time the cap space is rotated at a predetermined speed in order to eliminate them of the mixture A micro-suction control procedure in the cap for controlling the suction pump to apply a high negative pressure;
The ink according to the cap trace suction control procedure, the air, the washing liquid and the cap after suction of those of the mixed solution, the peripheral edge portion by causing elapsed the second standby time while it is touching the nozzle plate A control procedure to reduce the negative pressure in the space;
A control procedure for opening the atmosphere release valve while keeping the peripheral end in close contact with the nozzle plate;
A control procedure for discharging the ink in the cap by rotating the suction pump slower than the low-speed rotation so as not to vibrate the ink in the nozzle while keeping the peripheral end in close contact with the nozzle plate ; ,
A spit control procedure for discharging a predetermined number of ink droplets by driving the print head to form the meniscus of the peripheral end portion to the nozzle of the print head while it is in close contact with the nozzle plate,
A program of a print head cleaning method, wherein:

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