JP6221946B2 - RECOVERY SYSTEM OF PRINT HEAD, INKJET RECORDING DEVICE EQUIPPED WITH THE SAME, AND RECOVERY METHOD OF RECORD HEAD - Google Patents

Description

  The present invention relates to an ink jet recording apparatus that performs recording by ejecting ink onto a recording medium such as paper, and in particular, recording in which ink adhering to an ink ejection surface is wiped with a wiper after forcibly ejecting ink from a nozzle of a recording head. It relates to a head recovery system.

  Recording devices such as facsimiles, copiers, and printers are configured to record an image on a recording medium such as paper or an OHP sheet. Depending on the recording method, ink jet, wire dot, thermal, etc. Can be classified. The ink jet recording method can be classified into a serial type in which recording is performed while the recording head scans a recording medium, and a line head type in which recording is performed by a recording head fixed to the apparatus main body.

  For example, a line head type ink jet recording apparatus uses a line head type ink jet head (recording head) for each color in which ejection nozzles are arranged at predetermined intervals over the entire width of the print area orthogonal to the conveyance direction of the recording medium. I have. The entire recording medium can be printed by discharging ink from the discharge nozzle corresponding to the printing position in accordance with the conveyance of the recording medium.

  In such an ink jet recording apparatus, there is a case where the straight performance of the ink is deteriorated (flying bending), non-ejection, etc., and the printing performance of the recording head is deteriorated. This may be caused by foreign matter such as paper dust, dust, and dust generated during paper transport, minute ink droplets (hereinafter referred to as mist) ejected together with ink droplets for image recording, and ink droplets. It is conceivable that the bounce mist generated when adhering to the medium adheres to the ink ejection surface of the recording head, resulting in meniscus abnormality. Further, it is conceivable that the sealing performance is lowered when the cap is attached due to the mist adhering to the place where the cap is attached and drying, and the viscosity of the ink in the nozzle is increased accordingly.

  Therefore, in order to prevent the ink from drying in the ink discharge nozzle provided with an opening on the ink discharge surface of the recording head and clogging of the nozzle due to the thickening of the ink in the ink discharge nozzle, the ink is forced from the nozzle. After the ink is pushed out (purged), the ink adhering to the ink ejection surface (nozzle surface) is wiped with a blade-like wiper to perform a recovery process of the recording head. However, it has been difficult to remove ink with increased viscosity and dried mist only by a simple purging operation and a wiping operation. In particular, as the solid component contained in the ink increases, the viscosity of the ink tends to increase, and wiping with a wiper becomes more difficult.

  Therefore, various methods for efficiently removing ink on the ink ejection surface have been proposed. For example, Patent Document 1 discloses an ink repellent surface, a depression with respect to the ink repellent surface, and an ink contact angle that is greater than that of the ink repellent surface. An inkjet head cleaning device including a suction nozzle having a small parent ink surface and a plurality of suction ports formed on the parent ink surface is disclosed.

  Further, Patent Document 2 includes a receiving portion that receives the ink discharged from the ink discharging means, and includes a coating member that applies ink to the ink discharging surface by moving the receiving portion in contact with the ink discharging surface. Ink jet for performing ink adhering to receiving part of application member, applying ink adhering to receiving part to ink ejection surface, and wiping ink ejection surface coated with ink with wiping member An image forming apparatus of the type is disclosed.

  Furthermore, in Patent Document 3, by wiping the nozzle surface after applying an ink overflow around the nozzle by applying a driving voltage such that ink droplets are not ejected from the nozzle and the ink overflows the nozzle surface, An ink jet recording apparatus that prevents the nozzle surface from being damaged is disclosed.

JP 2012-91419 A JP 2011-11498 A JP 2006-218747 A

  However, in the method of holding the purged ink and sucking the waste ink as in Patent Document 1, it is difficult to completely remove the ink from the ink ejection surface having reduced water repellency. Further, as in Patent Document 2, when an application member having a receiving portion for holding ink is used, there is a problem in that the apparatus is increased in size as compared with a case where a wiper blade is used alone.

  On the other hand, the method of Patent Document 3 has an effect of preventing the nozzle surface from being damaged by the ink overflow formed around the nozzle and redispersing the dried mist adhering to the vicinity of the nozzle by the ink overflow. However, since the mist adhering to the position away from the ink overflow cannot be sufficiently redispersed, it is difficult to surely wipe off the mist adhering to the entire nozzle surface.

  SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a recording head recovery system capable of effectively removing mist and foreign matter adhering to the ink ejection surface with a simple configuration, an ink jet recording apparatus including the same, and a recording head recovery method. The purpose is to provide.

  In order to achieve the above object, a first configuration of the present invention is a recording head recovery system provided with a nozzle region in which a discharge nozzle for discharging ink is opened on a recording medium, and includes a wiper, a drive mechanism, And a control unit. The wiper is pressed against the wiping start position outside the nozzle region. The drive mechanism reciprocates the wiper along the ink discharge surface. The control unit controls the ejection and ejection of ink from the ejection nozzle and the operation of the drive mechanism. The control unit forcibly pushes the ink from the ejection nozzles to attach the purge ink to the nozzle area, and wipes the purge ink by moving the wiper along the ink ejection surface from the wiping start position. A discharge wipe operation that spreads ink on the ink discharge surface by sequentially discharging ink from the discharge nozzle in accordance with the timing when the ink passes, and the ink discharge surface is spread by moving the wiper along the ink discharge surface. The recovery operation of the recording head that sequentially performs the ink wiping operation for wiping the discharged ink can be performed.

  According to the first configuration of the present invention, after the purge ink adhering operation, the wiper is moved to the edge of the ink discharge surface while the wiper is pressed against the ink discharge surface, and in accordance with the timing when the wiper passes. By performing a discharge wipe operation that sequentially discharges ink from the discharge nozzle, the ink is spread over the entire area of the ink discharge surface, so that even if the ink discharge surface is formed of a highly water-repellent material, the ink can be removed. It is possible to spread the coating, and foreign matters such as mist and paper dust that have adhered to and dried on portions other than the nozzle region can be redispersed in the ink immediately after ejection. Accordingly, it is possible to effectively suppress ejection defects such as deterioration in straightness of ink and non-ejection caused by foreign matters attached to the ink ejection surface of the recording head.

The figure which shows schematic structure of the inkjet recording device which concerns on one Embodiment of this invention. The figure which looked at the 1st conveyance unit and recording part of the ink-jet recording device shown in Drawing 1 from the upper part View of the recording unit from diagonally above Side view of the recording head constituting the line head of the recording unit View of the recording head viewed from the ink ejection surface Diagram showing the configuration of the dot formation part of the recording head The figure which shows the ink flow path from the ink tank of the inkjet recording device of this embodiment to a recording head. A view of the wiping mechanism mounted on the maintenance unit from above. The figure which looked at the carriage which constitutes the wiping mechanism from diagonally above A view of the support frame constituting the wiping mechanism as seen from above. The figure which shows the state which removed the wiping mechanism from the unit housing | casing of the maintenance unit It is a perspective view of the raising / lowering mechanism arrange | positioned at a unit housing | casing, and is a figure which shows the state which has a lift member in a horizontal state It is a perspective view of the raising / lowering mechanism arrange | positioned at a unit housing | casing, and is a figure which shows the state which the lift member stood up from the state of FIG. Diagram of lift members that constitute the lifting mechanism The figure which shows the state which has arrange | positioned the maintenance unit under the recording part The figure which shows the carriage, wiper, support frame, raising / lowering mechanism in the maintenance unit in the state of FIG. FIG. 16 is a diagram illustrating a state in which the support frame and the carriage are lifted by the lifting mechanism from the state of FIG. 16 and the wiper is disposed at a predetermined interval from the ink discharge surface. The figure which shows the state which pushed the ink from the recording head in the state which made the wiper oppose the edge part vicinity of the nozzle area | region R. A view of the ink ejected from the recording head viewed from the ink ejection surface side with the wiper facing the end of the nozzle area. Diagram around the ink ejection nozzle while the wiper is passing in the recovery operation of the print head FIG. 20 is a diagram illustrating a state in which ink is ejected from the ink ejection nozzle through which the wiper passes. The figure which shows the state which moved the wiper to the downstream edge of the 1st direction of the recording head. FIG. 5 is a diagram of a state in which the wiper is moved to the downstream side edge in the first direction of the recording head as viewed from the ink ejection surface side. The figure which shows the state which moves a wiper to a 2nd direction from the state of FIG. 22, and wipes off the ink of an ink discharge surface. The figure which shows the state which a support frame and a carriage descend | fall by the raising / lowering mechanism, and the wiper was spaced apart from the ink discharge surface.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an ink jet recording apparatus 100 according to an embodiment of the present invention. FIG. 2 shows the first transport unit 5 and the recording unit 9 of the ink jet recording apparatus 100 shown in FIG. FIG. 3 is a diagram of the recording unit 9 as viewed obliquely from above, FIG. 4 is a diagram of the recording heads 17a to 17c constituting the line heads 11C to 11K of the recording unit 9, and FIG. 5 is the recording head 17a. To 17c as viewed from the ink ejection surface F side, and FIG. 6 is a diagram illustrating the configuration of the dot forming portions of the recording heads 17a to 17c. 3 shows a state in which the recording unit 9 is viewed from the back side in FIG. 1 (upper side in FIG. 2), and the arrangement of the line heads 11C to 11K is opposite to that in FIGS. Further, since the recording heads 17a to 17c have the same shape and configuration, the recording heads 17a to 17c are shown in one drawing in FIGS.

  As shown in FIG. 1, a paper feed tray 2 that accommodates paper S is provided on the left side of the inkjet recording apparatus 100, and the paper S that is accommodated at one end of the paper feed tray 2 is placed at the uppermost position. A sheet feeding roller 3 for conveying and feeding one sheet at a time from the sheet S to a first conveying unit 5 to be described later, and a driven roller 4 that is pressed against the sheet feeding roller 3 and driven to rotate are provided.

  A first transport unit 5 and a recording unit 9 are disposed on the downstream side (right side in FIG. 1) of the paper feed roller 3 and the driven roller 4 with respect to the paper transport direction (arrow X direction). The first transport unit 5 includes a first drive roller 6 disposed on the downstream side in the paper transport direction, a first driven roller 7 disposed on the upstream side, the first drive roller 6 and the first driven roller 7. The first conveyance belt 8 is configured to include the first conveyance belt 8 that is stretched, and the first driving roller 6 is rotated in the clockwise direction by a control signal from the control unit 110 of the inkjet recording apparatus 100. 8 is transported in the direction of arrow X.

  Here, since the first drive roller 6 is disposed on the downstream side in the paper conveyance direction, the conveyance surface of the first conveyance belt 8 (upper side surface in FIG. 1) comes to be pulled by the first drive roller 6. The tension on the conveying surface of the first conveying belt 8 can be increased, and the sheet S can be conveyed stably. In addition, a sheet made of dielectric resin is used for the first transport belt 8, and a (seamless) belt mainly having no seam is used.

  The recording unit 9 includes a head housing 10 and line heads 11C, 11M, 11Y, and 11K held by the head housing 10. These line heads 11C to 11K are supported at such a height that a predetermined interval (for example, 1 mm) is formed with respect to the conveying surface of the first conveying belt 8, and as shown in FIG. A plurality (three in this case) of recording heads 17a to 17c are arranged in a zigzag pattern along the orthogonal paper width direction (vertical direction in FIG. 2). The line heads 11 </ b> C to 11 </ b> K have a recording area that is equal to or larger than the maximum width of the sheet S to be transported, and the ink ejection nozzles 18 corresponding to the printing position with respect to the sheet S transported on the first transport belt 8. Ink can be ejected from.

  As shown in FIGS. 4 and 5, a nozzle region R in which a large number of ink discharge nozzles 18 are arranged is provided on the ink discharge surfaces F of the recording heads 17a to 17c. As shown in FIGS. 2 and 3, the three recording heads 17 a to 17 c constituting the same line heads 11 </ b> C to 11 </ b> K include a part of the ink discharge nozzles 18 provided in the respective recording heads 17 a to 17 c. The end portions are arranged so as to overlap in the paper transport direction.

  As shown in FIG. 6, on the ink ejection surfaces F of the recording heads 17 a to 17 c, ejection ports 18 a having a minute diameter that are openings of the ink ejection nozzles 18 are arranged in the longitudinal direction (main scanning direction) of the ink ejection surface F. Are provided over at least the maximum width of the print area.

  The recording heads 17a to 17c each have a water repellent film 73 that covers a portion of the ink ejection surface F other than the ejection port 18a, a pressurization chamber 75 that is provided for each ejection port 18a, and a pressurization chamber 75. And a nozzle channel 76 that communicates with the ink discharge nozzles 18, and a common channel 77 that supplies ink to the plurality of pressure chambers 75 from the ink tank 20 (see FIG. 7) that stores ink. The pressurizing chamber 75 and the common flow channel 77 communicate with each other through a supply hole 79, and ink is supplied from the common flow channel 77 to the pressurizing chamber 75 through the supply hole 79. The ink discharge nozzle 18 is continuous from the inside of the pressurizing chamber 75 to the discharge port 18a through the nozzle flow path 76. Of the walls of the pressurizing chamber 75, the wall on the opposite side to the ink discharge surface F is constituted by a diaphragm 80. The diaphragm 80 is continuously formed over the plurality of pressurizing chambers 75, and the common electrode 81 formed continuously over the plurality of pressurizing chambers 75 is similarly laminated on the diaphragm 80. Yes. A separate piezoelectric element 71 is provided for each pressurizing chamber 75 on the common electrode 81, and a separate individual electrode 83 is provided for each pressurizing chamber 75 so as to sandwich the piezoelectric element 71 together with the common electrode 81. .

  Each piezoelectric element 71 is individually driven by applying a drive pulse generated by a drive pulse generator (not shown) of the head driver to the individual electrode 83. The deformation of the piezoelectric element 71 due to this driving is transmitted to the diaphragm 80, and the pressurizing chamber 75 is compressed by the deformation of the diaphragm 80. As a result, pressure is applied to the ink in the pressurizing chamber 75, and the ink that has passed through the nozzle flow path 76 and the ink discharge nozzle 18 is discharged onto the paper as ink droplets from the discharge port 18a (image forming operation). It should be noted that ink is contained in the ink ejection nozzle 18 even while no ink droplet is ejected, and the ink forms a meniscus surface M in the ink ejection nozzle 18.

  In the recording heads 17a to 17c constituting the line heads 11C to 11K, inks of four colors (cyan, magenta, yellow, and black) stored in the ink tank 20 (see FIG. 7) are respectively stored in the line heads 11C to 11K. Supplied for each color.

  Each of the recording heads 17a to 17c is a sheet that is sucked and held on the transport surface of the first transport belt 8 in accordance with image data received from an external computer or the like by a control signal from the control unit 110 (see FIG. 1). Ink is ejected from the ink ejection nozzle 18 toward S. As a result, a color image in which four colors of cyan, magenta, yellow, and black are superimposed is formed on the sheet S on the first conveying belt 8.

  Further, in order to prevent ink ejection failure due to drying or clogging of the recording heads 17a to 17c, a purge operation for pushing out ink from the ink ejection nozzles 18 of all the recording heads 17a to 17c at the start of printing after being stopped for a long time. In addition, during the printing operation, the ink ejection amount of the recording heads 17a to 17c with the ink ejection amount equal to or less than the specified value is discharged from the ink ejection nozzles 18 to discharge the ink having a high viscosity in the nozzles. Prepare for printing.

  In addition, as a method for ejecting ink from the recording heads 17a to 17c, for example, a piezo method in which ink is ejected using a piezo element (not shown), or a thermal ink jet in which bubbles are generated by a heating element and ink is ejected by applying pressure. Various methods such as a method can be applied.

  Returning to FIG. 1, the second transport unit 12 is arranged on the downstream side (right side in FIG. 1) of the first transport unit 5 with respect to the paper transport direction. The second transport unit 12 includes a second drive roller 13 disposed on the downstream side in the paper transport direction, a second driven roller 14 disposed on the upstream side, and the second drive roller 13 and the second driven roller 14. And the second transport belt 15 is stretched, and the second driving roller 13 is driven to rotate in the clockwise direction, whereby the paper S held on the second transport belt 15 is transported in the arrow X direction. Is done.

  The paper S on which the ink image is recorded by the recording unit 9 is sent from the first transport unit 8 to the second transport unit 12, and the ink ejected on the surface of the paper S while passing through the second transport unit 12 is dried. Is done. A maintenance unit 19 and a cap unit 90 are disposed below the second transport unit 12. The maintenance unit 19 moves below the recording unit 9 when performing the above-described purge, wipes the ink pushed out from the ink discharge nozzles 18 of the recording heads 17a to 17c, and collects the wiped ink. The cap unit 90 horizontally moves below the recording unit 9 when capping the ink ejection surfaces F (see FIG. 4) of the recording heads 17a to 17c, and further moves upward to be attached to the lower surfaces of the recording heads 17a to 17c. Is done. The detailed configuration of the maintenance unit 19 will be described later.

  Further, on the downstream side of the second transport unit 12 with respect to the paper transport direction, a discharge roller pair 16 that discharges the paper S on which an image is recorded to the outside of the apparatus main body is provided. Is provided with a discharge tray (not shown) on which the sheets S discharged outside the apparatus main body are stacked.

  Next, ink supply from the ink tank 20 to the recording heads 17a to 17c during printing and ink ejection from the recording heads 17a to 17c during purging will be described. FIG. 7 is a diagram showing ink flow paths from the ink tank 20 to the recording heads 17a to 17c of the ink jet recording apparatus 100 of the present invention. 7 is provided between the ink tank 20 of each color and the recording heads 17a to 17c. Here, an ink flow path for an arbitrary color will be described.

  As shown in FIG. 7, a syringe pump 21 is disposed between the ink tank 20 and the recording heads 17a to 17c. The ink tank 20 and the syringe pump 21 are connected by a first supply path 23 made of a tube member, and the syringe pump 21 and the common flow path 77 (see FIG. 6) in the recording heads 17a to 17c are the second made of a tube member. They are connected by a supply path 25.

  The first supply path 23 is provided with an inflow side valve 27, and the second supply path 25 is provided with an outflow side valve 29. By opening and closing the inflow side valve 27, the movement of ink in the first supply path 23 is permitted or restricted, and by opening and closing the outflow side valve 29, the movement of ink in the second supply path 25 is permitted or restricted. .

  The syringe pump 21 includes a cylinder 21a and a piston 21b. The cylinder 21 a is connected to the first supply path 23 and the second supply path 25, and the ink 22 in the ink tank 20 flows into the cylinder 21 a through the first supply path 23. Further, ink is discharged from the cylinder 21 a through the second supply path 25, and the discharged ink is supplied to the recording heads 17 a to 17 c and is disposed in the nozzle region R of the ink discharge surface F through the ink discharge nozzle 18. The ink is discharged from the discharge port 18a.

  The piston 21b can be moved up and down by a drive device (not shown). A packing (not shown) such as an O-ring is mounted on the outer periphery of the piston 21b to prevent ink leakage from the cylinder 21a, and the piston 21b can slide smoothly along the inner peripheral surface of the cylinder 21a. It is like that.

  At normal time (printing time), as shown in FIG. 7, the inflow side valve 27 and the outflow side valve 29 are both open, and the piston 21b is stopped at a preset position so that the inside of the cylinder 21a. Is filled with a substantially constant amount of ink. The ink 22 is supplied from the cylinder 21a to the recording heads 17a to 17c by the surface tension (meniscus) between the cylinder 21a and the recording heads 17a to 17c.

  FIG. 8 is a diagram showing the wiping mechanism 30 mounted on the maintenance unit 19. The wiping mechanism 30 includes a substantially rectangular carriage 31 to which a plurality of wipers 35 a to 35 c (see FIG. 9) are fixed, and a support frame 40 that supports the carriage 31. Rail portions 41a and 41b are formed at opposing edges of the upper surface of the support frame 40. The sliding rollers 36 provided at the four corners of the carriage 31 abut against the rail portions 41a and 41b. The support frame 40 is slidably supported in the direction of the arrow AA ′.

  FIG. 9 is a view of the carriage 31 constituting the wiping mechanism 30 shown in FIG. 8, and FIG. 10 is a view of the support frame 40 constituting the wiping mechanism 30 shown in FIG. As shown in FIG. 9, the carriage 31 includes first stays 32 a and 32 b that are slidably engaged with rail portions 41 a and 41 b of the support frame 40 via a slide roller 36, and first stays 32 a and 32 b. The second stays 33a, 33b, and 33c fixed in a bridging manner are formed in a frame shape.

  Rack teeth 38 that mesh with the input gear 43 (see FIG. 8) held by the support frame 40 are formed on the first stay 32a. When the input gear 43 rotates in the forward and reverse directions, the carriage 31 reciprocates in the horizontal direction (the direction of the arrow AA ′ in FIG. 8) along the support frame 40.

  The wipers 35a to 35c are members for wiping off the ink pushed out from the ink discharge nozzles 18 of the recording heads 17a to 17c. The wipers 35 a to 35 c are pressed from a substantially vertical direction to a wiping start position outside the nozzle region R (see FIG. 5) where the nozzle surface of the ink discharge nozzle 18 is exposed, and the ink discharge including the nozzle region R by the movement of the carriage 31. The surface F is wiped off in a predetermined direction (the direction of arrow A in FIG. 8).

  Four wipers 35a are fixed to the second stay 33a at substantially equal intervals. Similarly, four wipers 35b are substantially fixed to the second stay 33b, and four wipers 35c are substantially omitted to the second stay 33c. Fixed at regular intervals. The wipers 35a and 35c are disposed at positions corresponding to the left and right recording heads 17a and 17c (see FIG. 3) constituting the line heads 11C to 11K, respectively. The wiper 35b is disposed at a position corresponding to the central recording head 17b (see FIG. 3) constituting each of the line heads 11C to 11K, and the movement direction of the carriage 31 (see FIG. 8) with respect to the wipers 35a and 35c. Arranged by a predetermined distance in a direction orthogonal to the direction of arrow AA ′.

  Gap rollers 37 are provided at four locations on the upper surfaces of the second stays 33a and 33c. The gap roller 37 contacts the head housing 10 of the recording unit 9 when the wiping mechanism 30 is raised to the recording unit 9 side in order to perform the wiping operation of the ink discharge surfaces F of the recording heads 17a to 17c by the wipers 35a to 35c. The contact state between the wipers 35a to 35c and the ink discharge surface F is kept constant by contact.

  As shown in FIG. 10, an ink collection tray 44 for collecting waste ink wiped off from the ink ejection surface F by the wipers 35 a to 35 c is disposed on the upper surface of the support frame 40. A groove portion 44a is formed in a substantially central portion of the ink collection tray 44 along the extending direction of the second stays 33a to 33c. The tray surfaces 44b and 44c on both sides of the groove portion 44a face the groove portion 44a. The slope is descending. An ink discharge hole 44d is provided in the groove 44a, and the bottom surface of the groove 44a is inclined downward toward the ink discharge hole 44d.

  Waste ink that has been wiped off from the ink discharge surface F by the wipers 35a to 35c and dropped onto the tray surfaces 44b and 44c is collected in the groove 44a and further flows in the groove 44a toward the ink discharge hole 44d. Thereafter, the waste ink is collected in a waste ink collection tank (not shown) through an ink collection path (not shown) connected to the ink discharge hole 44d.

  Next, the elevating mechanism 50 for elevating the wiping mechanism 30 of this embodiment will be described. 11 is a view showing a state in which the wiping mechanism 30 is removed from the unit housing 45 of the maintenance unit 19 (located below the carriage 31 shown in FIG. 8). FIGS. It is a figure of the raising / lowering mechanism 50 arrange | positioned. On the bottom surface 45a of the unit housing 45, an elevating mechanism 50 in which two lift members 50a are fixed to both ends of the shaft 50b has side surfaces 45b facing the moving direction of the carriage 31 (arrow AA ′ direction in FIG. 8), A pair is arranged along 45c. That is, the elevating mechanism 50 is disposed at a position facing both ends in the width direction of the head housing 10 of the recording unit 9 (upper and lower ends in FIG. 2). In FIG. 11, the lifting mechanism 50 on the side surface 45c is not shown. The side surface 45d adjacent to the side surfaces 45b and 45c of the unit housing 45 is provided with a motor 47 and a drive transmission shaft 48 that transmits the rotational driving force of the motor 47 to the shaft 50b.

  FIG. 14 is a perspective view of a lift member 50 a that constitutes the lifting mechanism 50. A lower end portion of the lift member 50a is fixed to the shaft 50b, and a push-up roller 53 is rotatably attached to the upper end portion of the lift member 50a. The push-up roller 53 is rotatable along a guide portion (not shown) formed at the lower end portion of the support frame 40. Accordingly, since the friction between the support frame 40 and the lift member 50a when operating the lifting mechanism 50 is reduced by the rotation of the push-up roller 53, a smooth lifting operation can be performed. Further, the push-up roller 53 is urged by a coil spring 55 in a direction away from the shaft 50b (upward in FIG. 14).

  When the shaft 50b of the right elevating mechanism 50 is rotated in the clockwise direction and the shaft 50b of the left elevating mechanism 50 is rotated in the counterclockwise direction from the state of FIG. 12, the lift member 50a that has fallen into the inside of the unit housing 45 is removed. It rises in the outer direction (arrow B direction), and the push-up roller 53 moves to one end side of the guide portion. Thereby, the lift member 50a is switched from the horizontal state to the standing state (the state shown in FIG. 13), and the carriage 31 is raised together with the support frame 40.

  On the other hand, when the shaft 50b of the right elevating mechanism 50 is rotated in the counterclockwise direction and the shaft 50b of the left elevating mechanism 50 is rotated in the clockwise direction from the state shown in FIG. It falls in the direction of the arrow B ′, and the push-up roller 53 moves to the other end side of the guide portion. As a result, the lift member 50 a is switched from the standing state to the horizontal state (the state shown in FIG. 12), and the carriage 31 is lowered together with the support frame 40.

  Next, the recovery operation of the recording heads 17a to 17c using the wiping mechanism 30 in the inkjet recording apparatus 100 of the present embodiment will be described. FIG. 15 is a diagram illustrating a state in which the maintenance unit 19 is disposed below the recording unit 9, and FIG. 16 is a diagram illustrating a positional relationship between the recording heads 17a to 17c and the wipers 35a to 35c at the start of the wiping operation. 16 and FIGS. 17, 18, and 23 to 25, which will be described later, show a state in which the recording unit 9 and the maintenance unit 19 are viewed from the downstream side in the sheet conveyance direction (left side in FIG. 15). Further, the support frame 40 is simplified and described in a plate shape, and the unit housing 45 describes only the bottom surface 45a. Further, the recovery operation of the recording heads 17a to 17c described below is to control the operations of the recording heads 17a to 17c, the wiping mechanism 30, and the lifting mechanism 50 based on a control signal from the control unit 110 (see FIG. 1). Executed by.

  When the recovery operation of the recording heads 17a to 17c is performed, first, the first transport unit 5 located below the recording unit 9 is lowered as shown in FIG. Then, the maintenance unit 19 disposed below the second transport unit 12 is moved horizontally and disposed between the recording unit 9 and the first transport unit 5. In this state, as shown in FIG. 16, the lift member 50a of the lifting mechanism 50 is in a horizontal state, and the wipers 35a to 35c fixed to the carriage 31 are separated from the ink ejection surfaces F of the recording heads 17a to 17c. .

(Purge ink adhesion operation)
Prior to the wiping operation, the wipers 35a to 35c are brought into contact with a stop position P (wiping start position) near the end of the nozzle region R of the ink ejection surface F of the recording heads 17a to 17c with a predetermined pressure. Specifically, as shown in FIG. 17, the support frame 40 and the carriage 31 are lifted by rotating the shaft 50 b of the elevating mechanism 50 to raise the lift member 50 a in the arrow B direction. At this time, the gap roller 37 provided on the carriage 31 is pressed against the lower surface of the head housing 10 by the biasing force of the coil spring 55 (see FIG. 14) of the lift member 50a, so that the wipers 35a to 35c are moved against the ink discharge surface F. It is always possible to press contact with a constant pressure.

  Next, the inflow valve 27 (see FIG. 7) is closed, and the syringe pump 21 (see FIG. 7) is pressurized (the piston 21b is pushed down from the state shown in FIG. 7), whereby the ink 22 in the cylinder 21a is supplied second. The recording heads 17a to 17c are supplied through the path 25. The supplied ink 22 is forcibly pushed out from the ink discharge nozzle 18 (purge operation). By this purging operation, the thickened ink, foreign matter and bubbles in the ink discharge nozzle 18 are discharged, and the recording heads 17a to 17c can be recovered.

  18 and 19 are a side view and a plan view of the recording heads 17a to 17c showing a state in which the ink 22 is pushed out from the ink ejection nozzle 18 with the wipers 35a to 35c facing the vicinity of the end of the nozzle region R, respectively. It is. As shown in FIG. 18, the wipers 35 a to 35 c are pressed into contact with the vicinity of the end of the purge ink 22 a pushed out from the ink discharge nozzle 18 (the left end in FIGS. 18 and 19) with the tip bent. Further, as shown in FIG. 19, the purge ink 22 a is pushed out to the ink discharge surface F along the shape of the nozzle region R where the ink discharge nozzle 18 exists.

(Discharge wipe operation)
18 and 19, the input gear 43 (see FIG. 8) is rotated forward to move the carriage 31 in the direction of arrow A in FIG. 17, so that the wipers 35 a to 35 c supported by the carriage 31 also eject ink. It moves along the surface F in the direction of the nozzle region R (from left to right in FIGS. 18 and 19, hereinafter referred to as the first direction). Since an upward force is applied to the support frame 40 by the lifting mechanism 50, the carriage 31 moves in the arrow A direction while maintaining the state where the gap roller 37 is pressed against the head housing 10.

  At this time, the wipers 35a to 35c sequentially pass through the ink discharge nozzle 18 (nozzle region R), but the wipers 35a to 35c discharge ink from the passing ink discharge nozzles 18. The wipers 35a to 35c are moved to the edge of the ink ejection surface F (the right edge in FIGS. 18 and 19) while sequentially ejecting ink in accordance with the timing when the wipers 35a to 35c pass.

  FIG. 20 is a view around the ink discharge nozzle 18 through which the wipers 35a to 35c pass, and FIG. 21 illustrates a state in which ink discharge is performed from the ink discharge nozzle 18 through which the wipers 35a to 35c pass in FIG. FIG. As shown in FIG. 20, the wipers 35a to 35c pressed against the ink discharge surface F are wiped with the edge portion 60 on the downstream side in the moving direction while wiping the purge ink 22a pushed out to the ink discharge surface F in the first direction (arrow). Direction).

  Then, as shown in FIG. 21, ink is discharged from the ink discharge nozzle 18 at the timing when the wipers 35 a to 35 c pass through the ink discharge nozzle 18 (more specifically, immediately after the edge portion 60 passes through the ink discharge nozzle 18). Do. As a result, the ink reservoir 22b is formed in the gap between the upper end surface 61 of the wipers 35a to 35c and the ink ejection surface F.

  In the state of FIG. 21, the wipers 35 a to 35 c move along the ink discharge surface F, so that the ink reservoir 22 b is stretched. Therefore, the wipers 35 a to 35 c are connected to the end of the ink discharge surface F as shown in FIGS. 22 and 23. When moving to the edge (the right edge in FIGS. 22 and 23), the ink 22 is uniformly spread over the entire area of the ink ejection surface F including the nozzle region R.

(Ink wiping operation)
Thereafter, a wiping operation for wiping off the ink 22 spread on the ink discharge surface F is performed. Specifically, the input gear 43 (see FIG. 8) is reversely rotated from the states of FIGS. 22 and 23 to move the carriage 31 in the direction opposite to the arrow A in FIG. 17 (the direction of the arrow A ′ in FIG. 8). Accordingly, as shown in FIG. 24, the wipers 35a to 35c supported by the carriage 31 are also in pressure contact with the ink discharge surface F in the direction of the nozzle region R along the ink discharge surface F (from right to left in FIG. 24). Direction, hereinafter referred to as the second direction). As a result, the ink 22 spread over the entire area of the ink ejection surface F is wiped off. Waste ink wiped off by the wipers 35a to 35c is collected in the ink collection tray 44 (see FIG. 10).

  After the wipers 35a to 35c move to the edge (left edge in FIG. 24) of the ink ejection surface F of the recording heads 17a to 17c, as shown in FIG. 25, the shaft 50b of the lifting mechanism 50 is rotated and lifted. By causing the member 50a to fall in the direction of the arrow B ', the wipers 35a to 35c are retracted downward from the ink ejection surfaces F of the recording heads 17a to 17c to return the maintenance unit 19 to the state shown in FIG. Finally, the maintenance unit 19 disposed between the recording unit 9 and the first transport unit 5 is moved horizontally and disposed below the second transport unit 12 to raise the first transport unit 5 to a predetermined position. Thus, the recovery operation of the recording heads 17a to 17c is completed.

  When the cap unit 90 is attached to the recording heads 17a to 17c, first, as shown in FIG. 15, the first belt conveyance unit 5 disposed to face the lower surface of the recording unit 9 is lowered. Then, the cap unit 90 disposed below the second belt conveyance unit 12 is horizontally moved between the recording unit 9 and the first belt conveyance unit 5 and disposed at a position facing the recording unit 9.

  Next, the cap unit 90 is pushed up by raising the first belt conveyance unit 5. Then, when the cap unit 90 comes into close contact with the recording heads 17a to 17c, the ascent of the first belt conveyance unit 5 is stopped to complete the mounting of the cap unit 90 to the recording heads 17a to 17c.

  In the configuration of the present embodiment, after the purge ink attaching operation, the wipers 35a to 35c are moved to the edge of the ink discharge surface F while the wipers 35a to 35c are pressed against the ink discharge surface F, and the wipers 35a to 35c are moved. The ink 22 is spread over the entire area of the ink ejection surface F by executing the ejection wipe operation that sequentially ejects ink from the ink ejection nozzle 18 in accordance with the timing at which the ink passes. Therefore, even when the ink discharge surface F is formed of a highly water-repellent material, the ink 22 can be spread on the ink discharge surface F, and the mist adhered to the portion other than the nozzle region R and dried Foreign matter such as paper dust can be redispersed in the ink 22 immediately after ejection.

  Furthermore, since the wiper operation and the ink wiping operation can be performed simply by reciprocating the wipers 35a to 35c in the first direction and the second direction along the ink discharge surface F, There is no need to separately provide an application member for spreading ink and a drive mechanism for the application member. Accordingly, foreign matters such as mist and paper dust attached to the ink ejection surface F can be effectively removed without complicating the configuration of the wiping mechanism 30.

  In the ejection wiping operation, the ink reservoir 22b formed in the gap between the wipers 35a to 35c and the ink ejection surface F is brought into contact with the ink ejection surface F for as long as possible, so that mist or paper dust adhered to the ink ejection surface F, etc. Can be sufficiently redispersed in the ink 22. For this reason, it is preferable to increase the ink discharge amount when forming the ink reservoir 22b or to reduce the moving speed of the wipers 35a to 35c in the discharge wipe operation.

  The ink discharge amount and the moving speed of the wipers 35a to 35c may be set as appropriate according to the physical properties of the ink 22, the wipers 35a to 35c and the ink discharge surface F to be used, and the frequency of the recovery operation of the recording head 17. When the ejection amount is increased, the amount of ink used other than image recording increases, and the maintenance cost of the inkjet recording apparatus 100 increases. Therefore, it is more preferable to slow down the moving speed of the wipers 35a to 35c in the discharge wiping operation. For example, it is preferable that the moving speed of the wipers 35a to 35c in the ejection wiping operation is slower than the moving speed of the wipers 35a to 35c in the ink wiping operation.

  Further, when the flow rate of the ink 22 to be pushed out when performing the purge ink attaching operation is slow, the ink 22 is pushed out only from the ink ejection nozzle 18 that is easily ejected (no clogging with thickened ink) in the nozzle region R. The ink 22 may not be pushed out from all the ink discharge nozzles 18 in the nozzle region R. Therefore, it is preferable to eject the ink 22 at a flow rate (for example, 0.15 cc / sec or more, preferably 0.20 cc / sec or more) at which the ink 22 is uniformly pushed out from the entire nozzle region R.

  In addition, when a large amount of foreign matter such as mist or paper dust adheres to the ink ejection surface F, after performing the ejection wiping operation a plurality of times, the ink wiping operation is performed, or the ejection wiping operation and the ink wiping are performed. By performing the ejection wiping operation and the ink wiping operation for two or more cycles, assuming that the operation is performed once, the redispersion time of the foreign matter can be secured, and a higher foreign matter removal effect can be expected.

  In addition, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the wipers 35a to 35c are reciprocated in the first direction and the second direction to perform the ejection wipe operation and the ink wiping operation. After wiping the wipers 35a to 35c from the ejection surface F and moving the carriage 31 in the direction of arrow A ', the wipers 35a to 35c are moved again in the first direction while being pressed against the stop position P, and the ink is wiped off. May be executed.

  As the drive mechanism of the carriage 31 including the rack teeth 38, the input gear 43, and the lifting mechanism 50, other conventionally known drive mechanisms can be used. The number of the ink discharge nozzles 18 of the recording heads 17a to 17c, the nozzle interval, and the like can be appropriately set according to the specifications of the inkjet recording apparatus 100. Further, the number of recording heads is not particularly limited. For example, one, two, or four or more recording heads 17 can be arranged for each of the line heads 11C to 11K.

  Further, the present invention can also be applied to an inkjet recording apparatus for monochrome printing that includes only one of the line heads 11C to 11K. In that case, since the recording heads 17a to 17c are provided one by one, the wipers 35a to 35c corresponding to the recording heads 17a to 17c may be fixed to the carriage 31 one by one. Hereinafter, the effects of the present invention will be described in more detail with reference to examples.

  When performing the recovery operation of the recording heads 17a to 17c of the present embodiment, the linear velocity (moving speed) of the wipers 35a to 35c in the ejection wipe operation and the ink ejection amount from the ink ejection nozzle 18 through which the wipers 35a to 35c are passing. We investigated the difference in the stretching effect of the ink when changing the. First, the carriage 31 moves reciprocally along the ink ejection surface F of the recording heads 17a to 17c and moves in a direction approaching or separating from the ink ejection surface F. The wipers 35a to 35c have a width of 30 mm and a height (projection amount). ) A test machine equipped with a rubber blade of 7 mm and a thickness of 1.5 mm made of EPDM (Asker hardness 60, rebound resilience about 60%) was produced.

The dot forming portions of the recording heads 17a to 17c have the structure shown in FIG. 6. The area of the pressurizing chamber 75 is 0.2 mm ² , the width is 200 μm, the depth is 100 μm, and the diameter of the nozzle flow path 76 is 200 μm. The diameter of the supply hole 79 is 30 μm, the length is 40 μm, the length of the ink discharge nozzle 18 is 30 μm, and the shape of the discharge port 18a is a circle having a radius of 10 μm. A recording head was prepared in which 166 dot forming portions having the above-described configuration were arranged on the ink ejection surface F in one row and 664 in a whole (four rows). The pitch of the ink ejection nozzles 18 in the same row was 150 dpi, and the adjacent rows were shifted by ¼ pitch to make 600 dpi as a whole.

  The ink 22 to be used was a water-based ink having the composition shown in Table 1, and after sufficiently stirring each component, the ink 22 was subjected to pressure filtration with a filter having a pore diameter of 5 μm to obtain ink 22.

  Then, the amount of overlap between the wipers 35a to 35c and the ink discharge surface F is set to 1 mm, the pressure is in contact with the highly water-repellent ink discharge surface F, the linear velocity of the wipers 35a to 35c, and the ink discharge while the wipers 35a to 35c are passing. The effect of stretching the ink 22 at the rear ends of the wipers 35a to 35c when the discharge wipe operation was executed while changing the ink discharge amount from the nozzle 18 was visually observed. The results are shown in Table 2. In Table 2, the case where stretching of the ink 22 occurred at the rear ends of the wipers 35a to 35c was marked as ◯, and the case where stretching of the ink 22 did not occur was marked as x.

As is apparent from Table 2, when the linear speeds of the wipers 35a to 35c are 10 mm / sec and 20 mm / sec, the ink discharge amount per ink discharge nozzle is 7.0 × 10 ⁻⁴ cc or more and the stretching effect is obtained. Was recognized. Further, when the linear speeds of the wipers 35a to 35c are 30 mm / sec and 50 mm / sec, the expansion effect is recognized when the ink discharge amount per ink discharge nozzle is 10.0 × 10 ⁻⁴ cc or more, and the wiper 35a When the linear velocity of .about.35c was 100 mm / sec, the stretching effect was recognized when the ink discharge amount per ink discharge nozzle was 20.0.times.10.sup.- ⁴ cc. That is, it can be seen that the effect of stretching the ink 22 increases as the linear velocity of the wipers 35a to 35c in the ejection wipe operation decreases and the amount of ejection of the ink 22 increases.

  When performing the recovery operation of the recording heads 17a to 17c of the present embodiment, the linear velocity (moving speed) of the wipers 35a to 35c in the ejection wipe operation and the ink ejection amount from the ink ejection nozzle 18 through which the wipers 35a to 35c are passing. We investigated the difference in mist removal effect when changing the mist. The configurations of the recording heads 17a to 17c and the wipers 35a to 35c and the composition of the ink 22 were the same as those in Example 1.

  As a test method, after the mist is attached to the highly water-repellent ink discharge surface F in advance and dried, the linear velocity of the wipers 35a to 35c and the amount of ink discharged from the ink discharge nozzle 18 through which the wipers 35a to 35c are passing. The degree of wiping of the mist adhering to the ink ejection surface F when the ejection wiping operation and the ink wiping operation were executed while changing the above was observed. In the evaluation method, the case where the ejection wiping operation and the ink wiping operation are performed once is defined as one cycle, ◯ when the mist is wiped in one cycle, △ when the mist is wiped in two cycles, and mist The residual case which required 3 cycles or more for wiping was set as x. The results are shown in Table 3.

As is apparent from Table 3, when the linear speeds of the wipers 35a to 35c are 10 mm / sec and 20 mm / sec, the ink discharge amount per ink discharge nozzle is 7.0 × 10 ⁻⁴ cc or more and mist is generated. Wiped in 1 cycle. Further, when the linear speed of the wipers 35a to 35c is 30 mm / sec, 50 mm / sec, the ink discharge amount per ink discharge nozzle is 10.0 × 10 ⁻⁴ cc or more, and the mist is wiped in one cycle. When the linear speed of the wipers 35a to 35c was 100 mm / sec, the ink discharge amount per ink discharge nozzle was 20.0 × 10 ⁻⁴ cc, and the mist was wiped in one cycle. That is, it can be seen that the mist wiping effect increases as the linear velocity of the wipers 35a to 35c in the discharge wipe operation decreases and the discharge amount of the ink 22 increases.

  From the above results, in order to obtain a stable mist removing effect while suppressing the ink consumption as much as possible, it was confirmed that it is preferable to reduce the linear speed of the wipers 35a to 35c in the discharge wipe operation as much as possible.

  The present invention is applicable to an ink jet recording apparatus that performs recording by ejecting ink from a recording head. By using the present invention, foreign matters such as mist and paper dust that have adhered to the ink ejection surface of the recording head and dried can be reliably removed, and it is effective for defective ejection of ink and a decrease in sealing performance when the cap is mounted. Thus, an ink jet recording apparatus having a recording head recovery system that can be suppressed to a low level is obtained.

DESCRIPTION OF SYMBOLS 9 Recording part 10 Head housing 11C-11K Line head 17a-17c Recording head 18 Ink discharge nozzle 19 Maintenance unit 22 Ink 22a Purge ink 22b Ink reservoir 30 Wiping mechanism 31 Carriage 35a-35c Wiper 38 Rack tooth (drive mechanism)
40 Support frame 43 Input gear (drive mechanism)
50 Lifting mechanism (drive mechanism)
60 Edge portion 61 Upper end surface 90 Cap unit 100 Inkjet recording apparatus 110 Control unit F Ink ejection surface R Nozzle region P Stop position

Claims (7)

A recording head recovery system provided with a nozzle region in which a discharge nozzle for discharging ink is opened on a recording medium,
A wiper pressed against the wiping start position outside the nozzle region;
A drive mechanism for reciprocating the wiper along an ink ejection surface including the nozzle region;
A controller that controls the ejection and ejection of ink from the ejection nozzle and the operation of the drive mechanism;
With
The controller is configured to forcibly push out ink from the ejection nozzle and to attach purge ink to the nozzle region; and
The wiper is moved along the ink discharge surface from the wiping start position to wipe purge ink, and ink is sequentially discharged from the discharge nozzles in accordance with the timing at which the wiper passes, whereby ink is applied to the ink discharge surface. Dispensing wipe operation to spread
An ink wiping operation for wiping the discharged ink spread on the ink discharge surface by moving the wiper along the ink discharge surface;
Recording head recovery system that sequentially performs   2. The recording head recovery system according to claim 1, wherein a movement speed of the wiper in the ejection wiping operation is slower than a movement speed of the wiper in the ink wiping operation.   3. The recording head recovery system according to claim 1, wherein the ink wiping operation is executed after the ejection wiping operation is repeatedly executed a plurality of times. 4.   3. The discharge wiping operation and the ink wiping operation are executed as one cycle when the discharge wiping operation and the ink wiping operation are executed once each, and the discharge wiping operation and the ink wiping operation are executed two or more cycles. The recording head recovery system described in 1. The discharge wiping operation is performed by moving the wiper in a first direction from the wiping start position toward the nozzle region, and the ink wiping operation is performed after the discharge wiping operation is performed. recovery system of the recording head according to any one of claims 1 to 4, characterized in that it is performed by moving the wiper in a second direction which is opposite to the direction.   An ink jet recording apparatus comprising the recording head recovery system according to claim 1. A method for recovering a recording head provided with a nozzle region in which a discharge nozzle for discharging ink is opened on a recording medium,
A purge ink adhering step for forcibly extruding ink from the ejection nozzle and adhering purge ink to the nozzle region;
After execution of the purge ink adhering step, the wiper is moved along the ink ejection surface including the nozzle area while the wiper is in contact with the wiping start position outside the nozzle area, and the wiper passes through the wiper. A discharge wiping step of spreading ink on the ink discharge surface by sequentially discharging ink from the discharge nozzle in accordance with the timing to perform,
An ink wiping step of wiping off the discharged ink spread on the ink discharge surface by moving the wiper along the ink discharge surface after the discharge wiping step is performed.