JP2015217593A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that it is necessary to periodically clean an ink jet head encapsulation cap which easily becomes dirty, that it is necessary to adequately remove deposits from the cap, and that a cap on which deposits exist is regarded as having encapsulation failure.SOLUTION: A carriage includes a mechanism for attaching/detaching a roller. When cleaning a cap, the carriage is moved to a storage part of the roller so that the roller is fitted to the carriage by using the attaching/detaching mechanism. By reciprocating scanning of the carriage on the cap, the cap is cleaned by the fitted roller. Foreign substances adhering to the cap are removed. After the cleaning, the roller is returned to the storage part and normal recording is restarted.

Description

  The present invention relates to an inkjet printer that records an image by ejecting ink.

  2. Related Art Inkjet printers that record images by ejecting ink from an inkjet head onto a recording medium such as paper or resin film are known. Inkjet printers are required to improve performance such as high image quality, durability, and reliability. If foreign matter adheres to the nozzle surface of the inkjet head, ejection failure such as ink not being ejected may occur due to the influence. For this reason, in a general ink jet printer, the ink adhering to the nozzle surface of the ink jet head is periodically wiped with an elastic wipe blade to remove the adhering matter. Further, the nozzle surface is sealed with a cap, and the inside of the cap is sucked to forcibly remove the thickened ink in the ink jet head and remove foreign substances clogged in the nozzle.

  The contact portion of the cap with the nozzle surface must be regularly cleaned so that there is no foreign matter. For example, the foreign matter is a solidified ink, a recording medium thread or paper dust. If such a foreign substance exists in the contact portion, the sealing cannot be completed completely, and there is a possibility that suction is not performed sufficiently.

  For example, as disclosed in Japanese Patent Application Laid-Open No. 2001-71519, a mechanism for cleaning the cap by wiping the contact surface of the cap with a blade has been considered.

Japanese Patent Laid-Open No. 2001-71519

  In the conventional technique, the cap is wiped with a blade made of an elastic body such as rubber, urethane, or a porous body. However, a flexible material is used for sealing the contact surface of the cap with the inkjet head. For this reason, there is a problem that the contact surface of the portion where the foreign matter is attached is deformed only by wiping with the blade, and the foreign matter remains without being sufficiently wiped off. Some types of ink are easy to solidify, and if the cap is dry, it may solidify on the spot. Moreover, since the cap surface is simply wiped off with a blade, the cap is liable to dry.

  In order to solve such a problem, the present invention provides an ink jet printer that can sufficiently remove foreign matter adhering to the cap and keep the contact surface of the cap with the ink jet head moist.

  The ink jet printer of the present invention includes an ink jet head that records an image by discharging ink onto a recording medium, a platen that supports the recording medium, and the ink jet head mounted on the recording medium supported by the platen. A carriage that reciprocally scans, a detection unit that detects the position of the carriage, a cap that seals the ink jet head and sucks ink from the ink jet head, and moves the cap in the contact / separation direction with respect to the ink jet head Maintenance means for moving the inkjet head to a position corresponding to the cap, lifting the cap by the lifting means, sealing the cap on the inkjet head, and sucking ink from the inkjet head Have means In addition, the inkjet printer further includes a roller that presses against the cap and cleans the cap, a gripping means that is mounted on the carriage and grips the roller rotatably, and a table on which the roller is placed. The cap is arranged at a predetermined height by the elevating means, the roller placed on the table is gripped by the gripping means, and the carriage is moved while the roller is gripped by the gripping means. The cap is cleaned by reciprocating while the roller is in contact with the cap.

  According to the present invention, the foreign matter adhering to the cap can be sufficiently removed and the contact surface of the cap with the inkjet head can be kept moist, so that the sealing performance with the inkjet head is excellent, and the ink in the inkjet head is suitable. Inkjet printers that can be sucked in can be provided.

FIG. 1 is a schematic view of an ink jet printer. FIG. 2 is a schematic view of a cap cleaning mechanism. FIG. 3 is a diagram illustrating the cleaning roller. FIG. 4 is a block diagram of the ink jet printer. FIG. 5 is a flowchart for explaining the operation of cleaning the cap.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view of an ink jet printer. As shown in FIG. 1, the inkjet printer 1 according to the present embodiment arranges the recording medium 18 horizontally, conveys the recording medium 18 from the back of the drawing in FIG. 1, ejects ink from the inkjet head 3, and records the recording medium 18. Images, characters, etc. corresponding to the recording data are recorded on the surface of the. The recording medium 18 is paper, a resin film, or the like. This paper conveyance direction is called the sub-scanning direction.

  The ink jet printer 1 includes a transport unit that transports the recording medium 18. In addition, the inkjet head 3 and the cleaning liquid dropping means 4 are mounted, and the carriage 2 that reciprocates in the direction intersecting the conveyance direction of the recording medium 18, here the orthogonal direction, and the wipe unit 10 that wipes the inkjet head 3. A capping unit 8 that caps the inkjet head 3, and a spit unit 11 that receives ink discharged from the inkjet head 3. The moving direction of the reciprocating scanning is called a main scanning direction. The ink jet printer 1 includes control means for controlling the entire apparatus including reception of recording data and control of recording operation.

  The conveying means includes a plurality of conveying roller pairs 16 driven by a motor on a substantially flat platen 17 extended in the depth direction of the paper surface of FIG. The transport roller pair 16 includes a grid roller having a parallel rotation axis and a pinch roller that is energized by the grid roller. The recording medium 18 is conveyed while being sandwiched between the grid roller and the pinch roller. As the grid roller rotates, the recording medium 18 is conveyed from the depth direction to the near side.

  The carriage 2 is provided so as to be movable along a carriage rail 13 extending in a direction perpendicular to the conveyance direction of the recording medium 18 above the conveyance means, the wipe unit 10, the spit unit 11, and the capping unit 8. Yes. In addition, a motor 15 that reciprocates the carriage 2 on the carriage rail 13 so as to be capable of position control and speed control is provided. The motor 15 is connected to the endless belt 12 to which the carriage 2 is fixed, and drives the endless belt 12. A linear scale 14 is provided in parallel with the carriage rail 13. A linear sensor for detecting the scale of the linear scale 14 is provided in the carriage 2. The position of the carriage 2 can be detected, and the positions of the plurality of ink jet heads 3 and the dropping means 4 fixed to the carriage 2 can be calculated accordingly, and the control means can acquire them.

In the present embodiment, four inkjet heads 3 are provided corresponding to four color inks of black, yellow, magenta, and cyan for performing color recording.
Although details of the inkjet head 3 are not shown, a plurality of nozzles that eject ink are arranged in a row, and the supplied ink is ejected by an ejection mechanism such as a piezoelectric element. The ink jet printer 1 causes the spit unit 11 to eject ink from the nozzles outside the image forming range, and ejects thickened ink or ejects to adjust the meniscus.

  Position control and speed control of the motor 15 that drives the carriage 2 are performed in accordance with control signals from the control means. During the recording operation, the motor 15 is controlled so that the inkjet head 3 reciprocates over the recording medium 18 at a predetermined speed. Further, the motor 15 moves the inkjet head 3 to a predetermined wiping position of the wipe unit 10 during the cleaning operation. Further, when capping, it is moved onto the capping unit 8, and when spitting, it is moved onto the spit unit 11.

  The wipe unit 10 wipes and cleans the nozzle surface of the inkjet head 3 by moving the wipe blade relative to the nozzle surface of the inkjet head 3 with the inkjet head 3 moved above the wipe unit 10. To do. The capping unit 8 discharges foreign matter and thickened ink from the inkjet head 3 by sucking ink from the inkjet head 3 from the nozzles to the outside. Also, the ink is prevented from drying by capping when not in use. The schematic configuration of the capping unit 8 includes a cap, lifting means for moving the cap up and down, a suction unit for sucking the inside of the cap, and a waste ink bottle 9 for storing the sucked ink. A cap is provided for each inkjet head 3. The lifting / lowering means performs a vertical movement for selectively switching the position of the cap in the vertical direction, and includes, for example, appropriate mechanical / electromagnetic / fluid lifting / lowering means.

  The carriage 2 includes gripping means 5 for gripping a cleaning roller 6 that cleans the cap. The cleaning roller 6 that is not in use is placed on a table 7 having a recess in which the rotation shaft of the cleaning roller 6 can be placed.

  FIG. 2 is a schematic view of a cap cleaning mechanism. In the capping unit 8, a cap 24 that seals the ink jet head 3 is disposed corresponding to the ink jet head 3. The cap 24 is disposed so that a contact portion 25 that contacts the nozzle surface of the inkjet head 3 surrounds the nozzle row. The cap 24 is provided with a spring 26 and biases the cap 24 in the direction of the nozzle surface. The carriage 2 is provided with gripping means 5 on the outer side on the dropping means 4 side. The holding means 5 is provided with a receiving portion 34 having an elliptical opening for receiving the rotation shaft 33 of the cleaning roller 6. The receiving portion 34 is moved from the outer side to the inner side of the rotating shaft 33 with respect to the rotating shaft 33 provided so as to protrude from both ends of the cleaning roller 6, and the rotating shaft 33 is inserted into the receiving portion 34 so as to be rotatable. Grasped.

  A recess 27 on which the rotary shaft 33 is placed is provided on the upper portion of the table 7. The recess 27 is made of a plate-like metal or plastic and has a horizontal portion 28 and a slope portion 29. The recess 27 is a recess provided in a part of the horizontal portion 28. The table 7 is provided with a cleaning roller detection sensor 30 that detects whether or not the cleaning roller 6 is placed. In FIG. 2, the rotation shaft 61 of the cleaning roller 60 drawn by a broken line is placed in the recess 27.

  Since the receiving part 34 holds the rotating shaft 33 by the elliptical opening, the rotating shaft 33 can move up and down along the ellipse. The lower limit 31 and the upper limit 32 of the movement range drawn with a broken line are the range of the opening of the receiving part 34, and the rotating shaft 33 moves up and down within this range. The depth of the recess 27 is within this movement range. Even if the rotary shaft 33 is placed in the recess 27, the rotary shaft 33 can move up and down, so that the carriage 2 can be moved after the gripping means 5 grips the rotary shaft 33. Further, the slope portion 29 is provided so that the carriage 2 and the base 7 do not come into contact with each other.

  The cleaning roller 6 is a porous resin roller. The cleaning roller 6 rotates while contacting the cap 24 by moving the carriage 2. Since the rotating shaft 33 moves while contacting the upper side of the elliptical opening of the receiving portion 34, the rotating shaft 33 can be rotated while pressing the cleaning roller 6 against the cap 24. The contact portion 25 of the cap 24 is a portion that contacts the nozzle surface while being deformed, and is made of a flexible resin. The cleaning roller 6 can clean the upper surface of the cap 24 including the contact portion 25. The capping unit 8 includes a cam 19 that is rotated by a cam shaft 20. In FIG. 2, the capping unit 8 is located at the lowermost part. As the cam shaft 20 and the cam 19 rotate, the capping unit 8 moves upward and can come into contact with the nozzle surface. When the cap 24 is cleaned by the cleaning roller 6, the cam 19 is rotated to fix the capping unit 8 at a predetermined position. For example, it is located at the bottom.

  Further, when cleaning the cap 24, ink or cleaning liquid may ooze out, and the tray 21 is disposed below the cap 24, receives spilled ink, etc., and passes through the tube 51 to the waste ink bottle 9. Pour. Ink or the like flows into the tube 51 due to the inclined surface provided on the tray 21. A suction pump 23 that sucks ink from each cap 24 is connected via a tube 22. The suction pump 23 causes the sucked ink to flow into the waste ink bottle 9.

  FIG. 3 is a diagram illustrating the cleaning roller. The case where the cleaning roller 6 is mounted on the carriage 2 by the gripping means 5 is drawn by a solid line. The cleaning roller 65 drawn with a dotted line shows a state in which the rotating shaft 66 drawn with a dotted line is placed in the concave portion 27 of the base 7. The carriage 62 and the gripping part 64 drawn with dotted lines show a state where they have moved to a place where the receiving part 63 drawn with dotted lines is located outside the rotation shaft 66. In this state, the gripping portion 64 moves so that the rotation shaft 66 is inserted into the receiving portion 63, whereby the cleaning roller 65 can be gripped.

  The positional relationship when viewed from above the cap 24 and the cleaning roller 6 is such that the width of the cleaning roller 6 is wider than the length of the cap 24 in the longitudinal direction. The entire upper surface of the cap 24 can be cleaned by the cleaning roller 6.

  The carriage 2 is provided with an inkjet head 3 and dropping means 4. The contact portion 25 of the cap 24 is disposed so as to surround the periphery of the nozzle row 35 of the inkjet head 3 when contacting the nozzle surface of the inkjet head 3. The inside of the contact portion 25 of the cap 24 is recessed. Moreover, the dent bottom part 37 at the bottom of the dent is flat. A suction hole 39 connected to the suction pump 23 is provided on one side of the hollow bottom portion 37 in the longitudinal direction. In addition, a porous resin cap sheet 38 is disposed in the recess bottom 37. This is to prevent ink from scattering when ink is ejected from the inkjet head 3 into the cap 24. The cleaning liquid discharge port 36 of the dripping means 4 is disposed at a position corresponding to the other side in the longitudinal direction of the recess bottom portion 37. The position of the droplet when the cleaning liquid is dropped into the cap 24 is the dropping range 40.

  FIG. 4 is a block diagram of the ink jet printer. The control unit 50 is a control unit including a CPU that executes processing operations such as calculation, control, determination, and setting. The control means 50 operates according to a control program stored in the ROM 41. The RAM 42 is used as a work area for temporary storage of data and processing by the control means 50. The carriage movement motor drive circuit 43 operates under the control of the control means 50 and drives the motor 15 that moves the carriage 2.

  The carriage position detection sensor 44 is a linear sensor that detects the scale of the linear scale 14. It is mounted on the carriage 2. Based on this sensor output, the position of the carriage 2 is calculated and acquired. The head drive circuit 45 is controlled by the control means 50. The inkjet head 3 is operated via the head drive circuit 45. When a plurality of inkjet heads 3 are mounted, the control unit 50 and the head driving circuit 45 can drive each inkjet head 3 individually. The head drive circuit 45 generates ink ejection timing or non-ejection timing for each inkjet head 3 based on information input from the control unit 50, and drives the inkjet head 3. When ink ejection is performed, an ON waveform is generated. When ink ejection is not performed, an OFF waveform is generated and transferred to each inkjet head 3. The ejection timing is calculated according to the position of the carriage 2.

  The cleaning roller gripping means driving circuit 46 operates under the control of the control means 50 and controls the operation of the gripping means 5 gripping or releasing the rotating shaft 33. The gripping means 5 includes a mechanism for moving a portion including the receiving portion 34 by, for example, a solenoid. The cleaning roller gripping means driving circuit 46 is a circuit for driving a solenoid. Further, in the case of a mechanism that moves a portion including the receiving portion 34 by a cam, it becomes a motor drive circuit that rotates the cam.

  The cleaning droplet lower motor drive circuit 47 operates under the control of the control means 50. The dropping means 4 drives a motor for dropping the cleaning liquid. The dropping means 4 is provided with a tube pump and drives a motor that drives the tube pump. When the motor is rotated forward, the cleaning liquid is discharged, and when stopped, it stops.

  The suction pump drive circuit 48 operates under the control of the control means 50. The motor for driving the suction pump 23 is driven. The suction pump 23 operates by driving a motor and sucks ink in the cap 24.

  The cleaning roller detection means 49 includes a cleaning roller detection sensor 30, and outputs information on whether or not the cleaning roller 6 is placed on the table 7 to the control means 50 by the cleaning roller detection sensor 30. The control means 50 can determine whether or not the cleaning roller 6 is placed on the table 7 based on the output of the cleaning roller detection sensor 30 if the cleaning roller 6 is not gripped. Further, if the cleaning roller 6 is being gripped, the carriage 2 is moved to the recess 27, and it can be determined whether or not the cleaning roller 6 is gripped by the output of the cleaning roller detection sensor 30 in that state.

FIG. 5 is a flowchart for explaining the operation of cleaning the cap. Each function of the inkjet printer 1 is controlled and operated by the control of the control means 50.
First, in step S <b> 1, the carriage 2 is moved over the cap 24. The cleaning liquid is dropped into the cap 24 by the dropping means 4. The cleaning liquid soaks into the cap sheet 38.

  Next, in step S <b> 2, the carriage 2 is moved to a position where the gripping means 5 grips the cleaning roller 6 placed on the table 7. Next, the cleaning roller 6 is gripped by the gripping means 5 in step S3.

  Next, in step S4, the carriage 2 is moved and cleaned on the cap 24 of the capping unit 8 while the cleaning roller 6 is held by the holding means 5. By this movement, the primary cleaning of the cap 24 is performed using the cleaning roller 6. The cleaning liquid dropped into the cap 24, that is, the cleaning liquid that has soaked into the cap sheet 38 presses while the cleaning roller 6 rotates, so that it spreads widely in the cap 24. Further, the cleaning liquid adhering to the cleaning roller 6 cleans not only the inside of the cap 24 but also the upper surface of the cap 24 including the contact portion 25 and its periphery. Preferably, the carriage 2 is reciprocated at least once so that the cleaning roller 6 cleans the cap 24 on the forward path and the backward path. Thereby, the cleaning liquid in the cap 24 can be sufficiently spread and spread over the upper surfaces of the cleaning roller 6 and the cap 24. Further, the cleaning roller 6 can be moved while being pressed while rotating on the upper surface of the cap 24 by the elasticity of the spring 26 and the elasticity and deformation of the contact portion 25. Since the contact portion 25 is deformed, the root of the contact portion 25 and the like can be cleaned. Although the rotary shaft 33 cannot move above the upper end of the elliptical opening of the receiving portion 34, the cap 24 can move downward due to the spring 26, and the cap 24 is pressed against the cleaning roller 6. While being cleaned.

  Next, in step S5, the suction pump 23 is driven. By driving the suction pump 23, the cleaning liquid immersed in the cap 24 and the cap sheet 38 is sucked. Since the upper surface of the cap 24 is released, it is not possible to suck all of the cap 24, but the cleaning liquid that has soaked into the cap sheet 38 is sucked and discharged.

  Next, in step S <b> 6, the top of the cap 24 is cleaned by the cleaning roller 6 while being sucked by the suction pump 23. Thereby, a further excess cleaning liquid can be discharged. Further, excess cleaning liquid adhering to the cleaning roller 6 can be discharged. Preferably, the cleaning roller 6 is reciprocated on the cap 24 at least once.

  Since a cleaning liquid or ink is mixed in the cap 24, bubbles may be generated, but can be cleaned by the cleaning roller 6. That is, bubbles such as bubbles can be crushed by bringing the cleaning roller 6 into contact with rotation, and residuals can be reduced by suction. Even when the normal nozzle surface is capped, the inside of the cap 24 is in a clean state, so that problems are less likely to occur. Further, the contact portion 25 of the cap 24 can be cleaned and wetted with a cleaning liquid. For example, when the main solvent is water ink, it is easy to dry. Therefore, if the contact portion 25 is dry, the ink adhering to it may be dried quickly and firmly fixed. However, since the upper surface of the cap 24 including the contact portion 25 can be moisturized to some extent by using a cleaning liquid that is harder to dry than ink, such a problem can be prevented.

  The present invention can be used for a printer having a cap for sealing an inkjet head.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Carriage 3 Inkjet head 4 Dropping means 5 Grip means 6 Cleaning roller 7 Unit 8 Capping unit 10 Wipe unit 11 Spit unit 12 Endless belt 13 Carriage rail 14 Linear scale 15 Motor 16 Conveying roller pair 17 Platen 18 Recording medium 24 Cap 25 Contact portion 26 Spring 27 Recess 33 Rotating shaft

Claims (8)

An inkjet head that records an image by ejecting ink onto a recording medium;
A platen for supporting the recording medium;
A carriage mounted with the inkjet head and reciprocally scanning the recording medium supported by the platen;
Detecting means for detecting the position of the carriage;
A cap for sealing the inkjet head and sucking ink from the inkjet head;
Elevating means for moving the cap in the contact / separation direction with respect to the inkjet head;
Inkjet having maintenance means for moving the inkjet head to a position corresponding to the cap, raising the cap by elevating means, sealing the cap on the inkjet head, and sucking ink from the inkjet head In the printer
A roller that presses against the cap and cleans the cap;
A gripping means mounted on the carriage and rotatably gripping the roller;
A table on which the roller is placed;
Further comprising
The cap is arranged at a predetermined height by the elevating means, the roller placed on the table is gripped by the gripping means, and the carriage is moved while the roller is gripped by the gripping means, An ink jet printer, wherein the cap is cleaned by reciprocating while the roller is in contact with the cap. The roller has an axis at the center of rotation, and the axis includes protrusions protruding from both side surfaces of the roller;
The base has a hollow portion on which a part of the protruding portion is placed, and movement of the shaft on the stand is restricted by placing the shaft in the hollow portion.
The gripping means includes a recess covering the tip of the protrusion, and the protrusion is operated by moving the recess from the tip end direction of the shaft toward the root direction in a state where the roller is placed on the table. The inkjet printer according to claim 1, wherein the roller is gripped by covering the recess with the concave portion.   The inkjet printer according to claim 1, further comprising a dropping unit that is mounted on the carriage and drops a cleaning liquid onto the cap. A suction pump connected to the cap and sucking ink from the inkjet head;
The cap and the suction pump are connected by a tube,
An absorbing member that absorbs the ink is disposed at the bottom of the cap;
The cap has an opening connected to the tube at a position corresponding to one end of the cap in the longitudinal direction of the absorbing member,
4. The cleaning liquid dropped from the means is dropped at a position closer to the other side in the direction opposite to the one side in the longitudinal direction than the central portion of the absorbing member. The inkjet printer of any one.   After dripping the cleaning liquid onto the cap, the roller is moved at least once with respect to the cap, and then the roller is moved at least once with respect to the cap while the suction pump is driven. The ink-jet printer according to claim 4, wherein the cap is cleaned.   The ink jet printer according to claim 4, wherein the roller contacts the absorbing member disposed on the cap when the roller is moved onto the cap.   The inkjet printer according to any one of claims 1 to 6, further comprising a tray that receives the spilled cleaning liquid under the cap.   8. The ink jet printer according to claim 1, wherein a main solvent of the ink is water, and the cleaning liquid is less likely to evaporate than the ink.

Images