JP2013136221A - Liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deterioration of a discharge property while suppressing the damage of a wiper.SOLUTION: When maintenance operation starts, a maintenance control part 72 controls a purge pump 69 so that liquid is purged from a discharge port of a head 10, and controls a wiper movement motor 63 so that a discharge surface is wiped by the wiper. When the number of counts by a maintenance number counter 73a for counting the number of times of purge operation and wipe operation reaches 10,000 or more and the number of counts by a print number counter 73b for counting the number of prints reaches 350,000, a cleaning control part 74 controls the wiper movement motor 63 so that cleaning operation in which the wiper is in slide-contact with a cleaning member is executed following the maintenance operation. When the cleaning operation is completed, the respective numbers of counts are reset.

Description

  The present invention relates to a liquid ejection device that ejects liquid from ejection ports.

  Impurities such as ink mist and paper dust may float inside the printer and adhere to the ink ejection surface. In this case, the ejection characteristics are likely to deteriorate due to nozzle clogging or the like. In order to prevent such nozzle clogging, it is preferable to wipe the ink discharge surface with a wiper. In this regard, a technique for cleaning the wiper every time the ink ejection surface is wiped is known in order to prevent the impurities removed from the ink ejection surface from adhering to the wiper and reducing the wiping performance (see, for example, Patent Documents). 1).

JP 2007-216426 A

  However, if the wiper is cleaned each time it is wiped, wear (damage) of the wiper is promoted, and conversely, the wiping performance may deteriorate.

  An object of the present invention is to provide a liquid ejection apparatus capable of suppressing a decrease in ejection characteristics while suppressing damage to a wiper.

  The liquid ejection apparatus of the present invention includes a liquid ejection head having an ejection surface on which an ejection port for ejecting liquid is disposed, a forced ejection mechanism for forcibly ejecting liquid from the ejection port, a wiper, and the ejection surface being wiped off. A wiper moving mechanism that moves the wiper so as to move, a cleaning member that cleans the wiper by contact with the wiper, and a control unit that controls the liquid discharge head, the forced discharge mechanism, and the wiper moving mechanism. The control means includes a maintenance control means for controlling the forced discharge mechanism and the wiper moving mechanism so that a maintenance operation for sequentially performing the forced discharge and the wiping is performed, and the maintenance operation is performed. Maintenance frequency counter that counts Liquid is discharged to two or more recording media, and the count value of the maintenance frequency counter is one or a plurality of threshold values (when the minimum value is two or more and there are a plurality of threshold values, they are adjacent to each other). Cleaning control means for controlling the wiper moving mechanism so that the cleaning is performed only when the difference between the matching threshold values is 2 or more).

  According to the present invention, since the liquid is discharged to two or more recording media since the wiper was last cleaned, and the wiper is cleaned only when the maintenance operation is performed more than once. Compared with the case where the wiper is cleaned every time the maintenance operation is performed, it is possible to suppress the discharge characteristics from being deteriorated while suppressing damage to the wiper.

  In the present invention, it is preferable that the cleaning control unit controls the wiper moving mechanism such that the moving speed of the wiper during the cleaning is slower than the moving speed of the wiper during the wiping. Thereby, the wiper can be efficiently cleaned.

  In the present invention, it is preferable that an impurity tray is disposed below the cleaning member. Thereby, the impurities scraped off from the wiper by the cleaning member can be reliably recovered.

  Further, in the present invention, the maintenance control unit is configured so that the liquid discharge amount related to the forced discharge immediately before the cleaning is performed is larger than the liquid discharge amount related to the other forced discharges. It is preferable to control the discharge mechanism. As a result, more liquid can be adhered to the wiper, and the wiper can be cleaned efficiently.

  In addition, in the present invention, it is preferable that the cleaning member and the ejection surface are arranged on the same straight line. According to this, since the wiper can easily reach the cleaning member, the structure of the wiper moving mechanism can be simplified.

  In the present invention, the elevating mechanism for elevating and lowering the liquid ejection head in the direction orthogonal to the ejection surface, an annular lip member that includes the elastic member and surrounds the liquid ejection head, and the lip member includes the elastic member And a cap member having a diaphragm connecting the liquid discharge head, and the elevating mechanism has the liquid discharge head at a retracted position where the wiper and the cap member are separated from each other in a direction perpendicular to the discharge surface. The cleaning control means controls the elevating mechanism when the wiper passes below the cap member when the wiping of the discharge surface is completed, so that the liquid discharge head is retracted. It has the 1st arrangement | positioning change means arrange | positioned to a position. According to this, since the wiper does not come into contact with the cap member when the dirty wiper passes below the cap member, it is possible to prevent the dirt attached to the wiper from attaching to the cap member.

  At this time, between a facing member that faces the discharge surface across a discharge space that faces the discharge surface, a contact position where the lip member contacts the facing member, and a spaced position that is separated from the facing member, A lip moving mechanism for moving the lip member, wherein the elevating mechanism elevates and lowers the liquid ejection head integrally with the cleaning member, and moves the liquid ejection head and the cleaning member to the retracted position. The recording position where an image is formed on the recording medium in the direction perpendicular to the ejection surface, and the wiping position below the recording position where the wiper contacts and wipes the ejection surface. The maintenance control means can be arranged in a state where the lip member is moved to the separation position by the lip moving mechanism. An wiper moving mechanism and an elevating mechanism are controlled so that the liquid ejection head is disposed at the wiping position, and the ejection surface is wiped by the wiper, and the cleaning control means controls the elevating mechanism, Second arrangement changing means for arranging the liquid ejection head at the wiping position; and rubbing control means for controlling the wiper moving mechanism to rub the wiper that has passed under the lip member against the cleaning member. It is more preferable to have it. This simplifies the configuration in which the wiper is rubbed against the cleaning member.

  Furthermore, at this time, it is still more preferable that the front end of the cleaning member on which the wiper is rubbed with respect to the direction orthogonal to the discharge surface is positioned below the discharge surface. According to this, since the wiper is rubbed in a strongly curved state, dirt adhering to the wiper can be cleaned over a wide range, and the number of cleanings of the wiper can be reduced.

  In the present invention, the liquid discharge head that discharges ink onto a recording medium, and the liquid discharge head that discharges ink while discharging a pretreatment liquid that acts on the ink to aggregate or deposit components in the ink. And a liquid discharge head provided upstream in the conveyance direction of the recording medium.

  According to the present invention, since the liquid is discharged to two or more recording media since the wiper was last cleaned, and the wiper is cleaned only when the maintenance operation is performed more than once. Compared with the case where the wiper is cleaned every time the maintenance operation is performed, it is possible to suppress the discharge characteristics from being deteriorated while suppressing damage to the wiper.

1 is a schematic side view showing an internal structure of an ink jet printer according to an embodiment of the present invention. It is a top view which shows the flow-path unit and actuator unit of the inkjet head contained in the printer of FIG. FIG. 3 is an enlarged view showing a region III surrounded by an alternate long and short dash line in FIG. 2. FIG. 4 is a partial cross-sectional view taken along line IV-IV in FIG. 3. It is the schematic which shows the head holder and humidification mechanism which are included in the printer of FIG. FIG. 6 is a partial cross-sectional view showing a region VI surrounded by an alternate long and short dash line in FIG. 5. It is the schematic which shows the connection form of all the heads contained in the printer of FIG. 1, and a humidification mechanism. FIG. 2A is a schematic top view of a wiper moving mechanism included in the printer of FIG. FIG. 2B is a schematic side view of a wiper moving mechanism included in the printer of FIG. FIG. 2 is a functional block diagram of a controller included in the printer of FIG. 1. It is a figure for demonstrating the function of the maintenance control part shown in FIG. It is a figure for demonstrating the function of the cleaning control part shown in FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  An overall configuration of an ink jet printer 1 according to an embodiment of the present invention will be described.

  As shown in FIG. 1, the printer 1 has a rectangular parallelepiped housing 1a. A paper discharge unit 31 is provided on the top of the casing 1a. The internal space of the housing 1a can be divided into spaces A, B, and C in order from the top. In the spaces A and B, a paper conveyance path that is continuous with the paper discharge unit 31 is formed. In the space C, a cartridge 39 as a liquid supply source for the head 10 is accommodated.

  In the space A, two heads 10, a transport unit 21 for transporting the paper P, a guide unit for guiding the paper P, a humidifying mechanism 50 (see FIG. 5) used for the humidifying operation, and a wiper moving mechanism 60 (see FIG. 8). Etc. are arranged. In the upper part of the space A, a controller 1p that controls the operation of each part of the printer 1 and controls the operation of the entire printer 1 is disposed.

  Based on the image data supplied from the external device, the controller 1p performs the sheet P conveyance operation by each part of the printer 1, the ink discharge operation synchronized with the sheet P conveyance, the maintenance operation related to the recovery / maintenance of the discharge performance, and the wiper 61. A cleaning operation for cleaning (see FIG. 8) is controlled. The maintenance operation includes a flushing operation, a purge operation, a wiping operation, a humidifying operation, and the like. The flushing operation is an ink discharging operation performed on all or part of the ejection ports 14a, and the actuator of the head 10 is driven. A predetermined number of ink droplets are discharged from the discharge port 14a. The driving of the actuator is based on flashing data different from the image data. The purge operation is an ink discharge operation performed for all of the ejection ports 14a, and the purge pump 69 (see FIG. 9) is driven. The ink in the head 10 is pressurized by the pump 69, and a predetermined amount of ink is discharged from each discharge port 14a. The wiping operation is a cleaning operation of the discharge surface 10 a performed after the flushing operation or the purge operation, and the discharge surface 10 a is wiped by the wiper 61. The humidifying operation is a water replenishing operation to the discharge port 14a, and humidified air is supplied into the discharge space S1 (see FIG. 5) facing the discharge surface 14a.

The transport unit 21 includes a platen 9 and a pair of transport nip rollers 5 and 6. The conveyance nip roller pairs 5 and 6 are arranged on both sides in the conveyance direction with the platen 9 interposed therebetween. Each of them is composed of a pair of roller members, and sandwiches the paper P up and down to transport the paper P in the transport direction. The conveyance nip roller pair 5 supplies the paper P onto the platen 9. The conveyance nip roller pair 6 sends the paper P from the platen 9 toward the paper discharge unit 31.
As shown in FIG. 1, the platen 9 together with the glass table 8 and the reversing mechanism 7 constitutes a means (opposing member switching means) for switching a facing member that faces the ejection surface 14 a. When the reversing mechanism 7 is operated, the platen 9 is disposed opposite to the ejection surface 14a during printing, and the glass table 8 is disposed during maintenance operation. Note that the switching of the facing member is performed by once moving the facing member switching means downward.

  Each head 10 is a line head having a substantially rectangular parallelepiped shape elongated in the main scanning direction. The lower surface of each head 10 is a discharge surface 10a in which a large number of discharge ports 14a (see FIGS. 3 and 4) are opened. The head 10 (P) is disposed on the upstream side in the transport direction, and the head (K) is disposed on the downstream side.

  At the time of printing, precoat droplets are ejected from the head 10 (P) onto the image forming area of the paper P, and ink droplets from the head 10 (K) are superimposed on this. As the precoat liquid, a liquid containing a cationic polymer, a polyvalent metal salt such as a magnesium salt, or the like is used, and an insoluble or hardly soluble metal complex is generated from the colorant of the ink. In pigment ink, aggregation of pigment pigments occurs. In dye inks, precipitation of dye pigments occurs. Thereby, ink bleeding is suppressed. Further, the ink is less likely to penetrate into the paper P, and the fixing on the surface is improved. As a result, the image quality is improved.

  The two heads 10 are supported by the housing 1 a via the head holder 3. At this time, the discharge surface 10a faces the platen 9 or the glass table 8 through a predetermined gap. The head holder 3 is provided with an annular cap 40, a pair of joints 51, and a cleaning member 65 for each head 10. Here, the sub-scanning direction is a direction parallel to the paper transport direction of the paper P by the transport unit 21, and the main scanning direction is a direction parallel to the horizontal plane and perpendicular to the sub-scanning direction.

  The head holder 3 is moved up and down by a holder lifting mechanism using a holder lifting motor 68 (see FIG. 9) as a power source. The head holder 3 can be arranged at three positions (printing position, wiping position, and retracted position in order from the bottom). The printing position is a position where the head 10 ejects droplets onto the paper P. The wiping position is a position where the wiper 61 wipes the ejection surface 10a. The retracted position is a position where the wiper 61 does not contact the ejection surface 10a.

  The guide unit includes an upstream guide portion and a downstream guide portion disposed with the transport unit 21 interposed therebetween. The upstream guide portion has two guides 27 a and 27 b and a pair of feed rollers 26. The guide unit connects the paper feeding unit 1 b and the transport unit 21. The downstream guide portion has two guides 29 a and 29 b and two pairs of feed rollers 28. The guide unit connects the transport unit 21 and the paper discharge unit 31.

  In the space B, the paper feeding unit 1b is arranged. The paper feed unit 1b includes a paper feed tray 23 and a paper feed roller 25, and the paper feed tray 23 can be attached to and detached from the housing 1a. The paper feed tray 23 is a box that opens upward, and can accommodate a plurality of types of paper P. The paper feed roller 25 feeds the uppermost paper P in the paper feed tray 23 and supplies it to the upstream guide unit.

  As described above, in the spaces A and B, the paper transport path from the paper feed unit 1b to the paper discharge unit 31 via the transport unit 21 is formed. Based on the print command received from the external device, the controller 1p includes a paper feed motor (not shown) for the paper feed roller 25, a feed motor (not shown) for the feed roller of each guide unit, a transport motor, and the like. To drive. The paper P sent out from the paper feed tray 23 is supplied to the transport unit 21 by the feed roller 26. When the paper P passes directly below each head 10 in the sub-scanning direction, the precoat liquid and the ink are sequentially ejected, and an image is formed on the paper P. Thereafter, the paper P is conveyed upward by the two feed rollers 28. Further, the paper P is discharged from the upper opening 30 to the paper discharge unit 31.

  In the space C, the ink unit 1c is detachably arranged with respect to the housing 1a. The ink unit 1c includes a cartridge tray 35, two cartridges 39 accommodated in the tray 35, and a water tank 54 (not shown) (see FIG. 5). Each cartridge 39 supplies a precoat liquid or ink to the corresponding head 10 via a tube (not shown).

  Next, the configuration of the head 10 will be described with reference to FIGS. 2 to 4 and 7. In FIG. 3, the pressure chamber 16 and the aperture 15 which are located below the actuator unit 17 and should be indicated by dotted lines are indicated by solid lines.

  As shown in FIGS. 2 to 4, the head 10 is a laminated body in which a flow path unit 12 with an actuator unit 17, a reservoir unit 11, a circuit board, and the like are laminated in order from the bottom. Eight actuator units 17 are fixed to the upper surface of the flow path unit 12. The FPC on which the driver IC is mounted connects the actuator unit 17 and the circuit board.

  As shown in FIG. 4, the flow path unit 12 is a laminated body in which nine metal plates 12 a to 12 i are sequentially laminated, and has a rectangular shape in plan view. With the opening 12y on the upper surface 12x as one end, inside the manifold channel 13, the sub-manifold channel 13a branched from the manifold channel 13, and the individual from the outlet of the sub-manifold channel 13a to the discharge port 14a via the pressure chamber 16 An ink flow path 14 is formed. The individual ink flow path 14 is formed for each ejection port 14 a and includes an aperture (throttle for adjusting the flow resistance) 15. A pressure chamber 16 opens in the adhesion region of the actuator unit 17 on the upper surface 12x. Discharge ports 14a are arranged in a matrix in a region facing the bonding region of the discharge surface 10a.

  The actuator units 17 are arranged in a zigzag pattern in two rows, avoiding the openings 12y. The actuator unit 17 has a piezoelectric actuator for each discharge port 14 a and covers each pressure chamber 16. The actuator is a unimorph type, and is composed of a plurality of stacked piezoelectric layers, an individual electrode facing the pressure chamber 16 on the outermost layer surface, and an individual electrode and a common electrode sandwiching one piezoelectric layer (outermost layer). .

  The reservoir unit 11 has an ink flow path including a reservoir formed therein. Ink from the cartridge 39 is temporarily stored. Irregularities are formed on the lower surface. One end of the ink flow path is open to the convex portion and communicates with the opening 12 y of the flow path unit 12. The recesses face the upper surface 12x and form a gap on the upper surface 12x. The actuator unit 17 is accommodated in the gap, and a slight gap remains between the recess.

  In the circuit board, various drive signals from the controller 1p are adjusted and transmitted to each actuator via the driver IC. When the drive signal is output, the actuator changes the volume of the pressure chamber 16 and the droplet is discharged from the corresponding discharge port 14a.

  Next, the configuration surrounding the head holder 3 will be described with reference to FIGS. 2, 5, and 6.

  The head holder 3 is a frame made of metal or the like, and supports the ejection surface 10a in a predetermined positional relationship with respect to the opposing member. Maintenance-related members are also supported for each head 10. For example, a part of the humidifying mechanism 50, the cap 40, the cleaning member 65, and the like. As a part of the humidifying mechanism 50, a supply port and a discharge port (a pair of joints 51) for humidified air correspond. The cap 40 is an annular member that covers the outer periphery of the discharge surface 10a. The cleaning member 65 is a rubbing member against the wiper 61.

  The pair of joints 51 are disposed close to both ends of the head 10 in the main scanning direction. In the humidification operation, as shown in FIG. 5, the right joint 51 supplies humidified air to the discharge space S1. The opening 51b on the lower surface is a supply port for humidified air. The left joint 51 collects air from the discharge space S1. The opening 51a on the lower surface is a discharge port. As shown in FIG. 6, the joint 51 includes a base end portion 51x and a cylindrical portion 51y. The hollow space 51z penetrates both the parts 51x and 51y up and down. The tip of the cylindrical part 51y has a tapered shape. The cylindrical portion 51y is inserted through the through hole 3a of the head holder 3, and the tube 55 is connected to the exposed tip portion. There is a slight gap between the cylindrical portion 51y and the through hole 3a, but it is filled with a sealing material or the like.

  The cap 40 includes an elastic body 41 and a movable body 42 that can be raised and lowered. The elastic body 41 is made of an elastic material such as rubber and includes four parts (a base part 41x, a protruding part 41a, a fixing part 41c, and a connecting part 41d) as shown in FIG.

  Among these, the fixing | fixed part 41c has a cross-sectional view T-shape. The flat upper end surface is bonded to the head holder 3 and surrounds the head 10 (discharge surface 10a) over the entire circumference. In the vicinity of the through hole 3a, a part of the fixed portion 41c is sandwiched between the head holder 3 and the joint 51 (base end portion 51x). The connecting portion 41d connects the lower end of the fixed portion 41c on the inner side and the lower end of the base portion 41x on the outer side. During this time, the connecting portion 41d extends while being curved. The bending of the connecting portion 41d enables the movable portion 42 of the base portion 41x to move up and down. The projecting portion (lip) 41a projects from the bottom surface of the base portion 41x in a tapered manner and has a triangular cross section. A concave portion 41b is formed on the upper surface of the base portion 41x, and the lower end of the movable portion 42 is fitted therein.

  The movable portion 42 is an annular metal member and can move in the vertical direction with respect to the head holder 3. The movable part 42 is connected to a lip lifting / lowering motor 44 (see FIG. 9) via a plurality of gears 43. When the lip lifting / lowering motor 44 is driven under the control of the controller 1p, the movable member 42 moves up / down with the base 51x. As the movable body 42 moves up and down, the protrusion 41a selects a contact position (see FIG. 5) where the tip 41a1 contacts the glass table 8 (surface 8a) and a separation position (see FIG. 6) separated from the surface 8a. Take it. For example, if the head 10 is in the printing position, the tip 41a1 contacts the surface 8a at the contact position, and the discharge space S1 is isolated from the external space S2. At this time, the discharge space S1 is in a sealed state. At the separation position, the discharge space S1 is opened to the external space S2 and is in an unsealed state.

  Further, the head holder 3 supports the head 10 and the cleaning member 65 on the same line in the main scanning direction. The cleaning member 65 sandwiches the end portion of the cap 40 adjacent to the head 10. The cleaning member 65 hangs down from the head holder 3, and the lower end of the protrusion 65a is located below the ejection surface 10a. The width of the lower end is larger than that of the wiper 61 in the sub scanning direction. In the cleaning member 65, the protrusion 65 a is rubbed against the wiper 61, and the wiping area of the wiper 61 is scraped off.

  The protrusion 41a is separated from the ejection surface 10a over the entire circumference of the ejection surface 10a (the lower surface of the head 10 shown in FIG. 2) in plan view.

  Next, the configuration of the humidifying mechanism 50 will be described with reference to FIGS. 5 and 7.

  The humidification mechanism 50 includes a joint 51, tubes 55, 56, and 57, a pump 53, and a tank 54 as shown in FIG. Two joints 51 are provided for each head 10, but the pump 53 and the tank 54 are shared by each head 10, as shown in FIG. Each of the tubes 55 and 57 includes main portions 55a and 57a common to each head 10, and two branch portions 55b and 57b branched from the main portions 55a and 57a and extending to the joint 51.

  The tube 55 has one end (the tip of each branch portion 55 b) fitted to one (left side in FIG. 5) the joint 51 and the other end (the end opposite to the branch portion 55 b of the main portion 55 a) to the pump 53. It is connected. The tube 56 connects the pump 53 and the tank 54. One end of the tube 57 (the tip of each branch portion 57b) is fitted into the joint 51 on the other side (the right side in FIG. 5), and the other end (the end portion of the main portion 57a opposite to the branch portion 57b) is connected to the tank 54. It is connected.

  The tank 54 stores water in the lower space and stores humid air in the upper space. The tube 56 is connected to a lower side (lower space) than the water surface in the tank 54, and the tube 57 is connected to an upper side (upper space) than the water surface in the tank 54. The tube 56 is provided with a check valve (not shown) so that air flows only in the direction of the arrow in FIG.

  Next, the wiper moving mechanism 60 will be described with reference to FIG. As shown in FIG. 8, the wiper moving mechanism 60 is provided for each head 10, and includes a wiper 61, a wiper holder 60a, a pair of guides 60b, and a wiper moving motor 63 (see FIG. 9). The wiper holder 60a supports the wiper 61 and is movable along the guide 60b. The guide 60b extends in the main scanning direction with the head 10 sandwiched in the sub scanning direction. The wiper 61 is a plate-like member made of an elastic material, and is arranged in the sub-scanning direction in the longitudinal direction. When the wiper moving motor 63 is driven, the wiper holder 60a reciprocates along the guide 60b. If the wiping operation and the cleaning operation are not performed, the wiper 61 is disposed at the standby position. As shown in FIG. 8A, the standby position is a position near the left end of the head 10 and faces the cleaning member 65 with the head 10 interposed therebetween.

  Next, the controller 1p will be described. The controller 1p includes a CPU (Central Processing Unit), a program executed by the CPU and a non-volatile memory that stores data used for these programs in a rewritable manner, and a RAM (Random Access) that temporarily stores data when the program is executed. Memory). Each functional unit constituting the controller 1p is constructed by cooperation of these hardware and software in the nonvolatile memory. As shown in FIG. 9, the controller 1p includes a head control unit 71, a maintenance control unit 72, a maintenance number counter 73a, a print number counter 73b, and a cleaning control unit 74.

  The head controller 71 controls the actuator unit 17 by an image forming operation and a flushing operation. In the image forming operation, corresponding to the transport of the paper P by the transport unit 21, each droplet based on the image data is ejected at a predetermined timing. In the flushing operation, each droplet (ink droplet and precoat droplet) is ejected based on the flushing data.

  The maintenance control unit 72 moves the head 10, the purge pump 69, and the wiper via the holder lifting / lowering motor 68 and the head control unit 71 so that the flushing operation, the purge operation, the wiping operation, and the humidification operation included in the maintenance operation are performed, respectively. The motor 63, the lip lift motor 44, the pump 53 of the humidifying mechanism 50, and the reversing mechanism 7 are controlled. Hereinafter, each operation will be described.

  The flushing operation is started immediately before the start of printing and at regular intervals after the start of printing. When the flushing operation is started, the maintenance control unit 72 drives the actuator unit 17 of the head 10 to forcibly discharge each droplet from the discharge port 14a in a desired discharge pattern.

  The purge operation is started immediately before the start of printing. When the purge operation is started, the maintenance control unit 72 controls the holder lifting / lowering motor 68 to place the head 10 on the placement and controls the reversing mechanism 7 so that the glass table 8 faces the discharge surface 10a. Thereafter, the maintenance control unit 72 controls the purge pump 69 to pressure-feed liquid (ink or precoat liquid) to the head 10 to forcibly discharge the liquid from all the ejection ports 14a. The drainage liquid is accommodated in a waste liquid tank (not shown) via the crow table 8. The maintenance control unit 72 determines whether or not the cleaning operation is performed after the purging operation and the subsequent wiping operation are completed. When it is determined that the cleaning operation is performed, the cleaning operation is performed. The drive of the purge pump 69 is controlled so that the discharge amount becomes larger than when it is determined that there is no. Whether or not the cleaning operation is performed is determined by determining whether or not the count number of the maintenance counter 73a is 10,000 or more and the count of the print number counter 73b is 350,000 or more.

  The wiping operation is performed following the flushing operation or the purge operation. Immediately before the wiping operation, as shown in FIG. 10A, the head 10 is in the printing position. In accordance with the wiping operation command, the maintenance control unit 72 controls the holder lifting / lowering motor 68 to place the head 10 at the retracted position shown in FIG. 10B, and controls the lip lifting / lowering motor 44 to move the protruding portion 41a. Place in a separate position. In this state, the wiper moving mechanism 60 is driven, and the wiper 61 moves to a position immediately before the ejection surface 10a through just below the protrusion 41a. Here, the maintenance control unit 72 lowers the head 10 and arranges it at the wiping position in FIG. In this state, the wiper moving mechanism 60 is driven, and the wiper 61 moves while being in contact with the discharge surface 10a. The wiping direction is rightward from the left standby position, as shown in FIG.

  Subsequently, the maintenance control unit 72 selects the next operation according to the necessity of the cleaning operation. If the cleaning operation is necessary, it stands by as it is. If the cleaning operation is not necessary, the maintenance control unit 72 temporarily places the head 10 in the retracted position and returns the wiper 61 to the standby position. Thereafter, the maintenance control unit 72 returns the head 10 to the printing position and completes the wiping operation.

  The humidifying operation is an operation for humidifying the inside of the ejection space S1 in the cap state (sealed state), and is started after printing is completed. During the following series of operations during the humidifying operation, the head 10 is disposed at the printing position. Further, the glass table 8 faces the discharge surface 10 a by the reversing mechanism 7.

  When the humidification operation is started, the maintenance control unit 72 first moves the movable body 42 downward by the rotation of the gear 43. The protrusion 41a moves from the separation position during printing (see FIG. 6) to the contact position (see FIG. 5). Thereby, the protrusion part 41a contact | abuts to the glass table 8, and makes discharge space S1 a sealing state. Note that the maintenance control unit 72 moves the protruding portion 41a to the contact position in the standby state or the resting state other than during printing, thereby setting the cap state.

  The maintenance control unit 72 drives the pump 53 to circulate humid air. When the pump 53 is driven into the discharge space S1, air is collected from the opening 51a, and humidified air is supplied from the opening 51b. At this time, the collected air reaches the lower space of the tank 54 via the tubes 55 and 56. The air is humidified by the water in the lower space and accumulates in the upper space. The humidified air that is stored has a humidity of almost 100%. The humid air in the upper space further reaches the opening 51b through the tube 57. The maintenance control unit 72 stops the pump 53 when a predetermined time has elapsed. By supplying the humidified air, the ink in the cap 40 is humidified, and ink thickening at the ejection port 14a is suppressed.

  In FIG. 5, black arrows indicate the air flow before humidification, and white arrows indicate the air flow after humidification. The maintenance control unit 72 controls the switching valves and the like (not shown) provided in the respective branch portions 55b and 57b shown in FIG. 7 together with the driving of the pump 53, whereby the air in the branch portions 55b and 57b is controlled. Selectively adjust the flow.

  As shown in FIG. 9, the maintenance frequency counter 73a counts and stores the number of times the purge operation and the subsequent wiping operation (maintenance operation) have been performed since the last cleaning operation. Further, the print number counter 73b counts and stores the number of prints (the number of pages if printing is performed in units of pages) since the last cleaning operation was performed. The counts stored in the maintenance counter 73a and the printed sheet counter 73b are reset to 0 when the cleaning operation is performed.

  The cleaning operation is started when the count number of the maintenance frequency counter 73a is 10,000 or more and the count number of the print number counter 73b is 350,000 or more. When the cleaning operation is started, as shown in FIG. 10C, the head 10 is disposed at the wiping position, and the wiper 61 is on the downstream side of the discharge surface 10a with respect to the wiping direction. It is arranged at a position immediately before 41a.

  As shown in FIG. 9, the cleaning control unit 74 includes a head position adjustment unit 74 a that controls the holder lifting motor 68 and a wiper movement control unit 74 b that controls the wiper movement motor 63. When the cleaning operation is started, first, the head position adjusting unit 74a controls the holder lifting / lowering motor 68 to raise the head 10 to the retracted position as shown in FIG. Subsequently, the wiper movement control unit 74b controls the wiper movement motor 63 to move the wiper 61 to just before the cleaning member 65 through the lower part of the protruding part 41a. During this time, since the head 10 is at the upper retracted position, contact between the wiper 61 and the cap 40 is prevented in advance. Next, the head position adjusting unit 74a lowers the head 10 to the wiping position. Thereafter, the wiper movement control unit 74 b moves the wiper 61 to the downstream side in the wiping direction with respect to the cleaning member 65. During this time, the wiper 61 rubs against the protrusion 65a of the cleaning member 65, and the wiper 61 is cleaned. The rubbing range of the wiper 61 is wider than the range of contact with the discharge surface 10a due to the protruding portion 65a protruding downward from the discharge surface 10a. Further, the moving speed of the wiper 61 at this time is slower than the moving speed of the wiper 61 in the wiping operation. By reducing the moving speed of the wiper 61, the wiper 61 can be efficiently cleaned and damage can be suppressed.

  After the wiper 61 passes through the cleaning member, the head 10 is arranged at the retracted position by the head position adjusting unit 74a. Thereafter, the wiper movement control unit 74b returns the wiper 61 to the standby position. The head position adjustment unit 74a waits for this and returns the head 10 to the printing position. This completes the cleaning operation.

  As described above, according to the printer 1 according to the present embodiment, when the count number of the maintenance number counter 73a is 10,000 or more and the count number of the print number counter 73b is 350,000 or more, Since the cleaning operation of the wiper 61 is started, it is possible to suppress the deterioration of the discharge characteristics due to the wiping operation while suppressing the damage to the wiper 61 as compared with the case where the cleaning of the wiper is performed every time the maintenance operation is performed. it can.

  Further, since the moving speed of the wiper 61 in the cleaning operation is slower than the moving speed of the wiper 61 in the wiping operation, the wiper 61 can be efficiently cleaned. Further, the wiper 61 can be further prevented from being damaged.

  Further, since the impurities scraped off by the cleaning member 65 are collected by the impurity tray 66 disposed below the cleaning member 65, the impurities scraped off from the wiper 61 can be reliably collected. Can do.

  In addition, since the discharge amount related to the purge operation when the cleaning operation is performed next is larger than the discharge amount related to the purge operation when the cleaning operation is not performed next, more liquid is supplied to the wiper in the cleaning operation. Can be easily scraped off of the impurities from the wiper 61.

  Further, since the cleaning member 65 and the ejection surface 10a of the adjacent head 10 are arranged on the same straight line when viewed from above, the wiper 61 can easily reach the cleaning member 65, and the wiper moving mechanism 60 The structure can be simplified. The time required for cleaning the wiper 61 can be shortened.

  Further, in the cleaning operation, the cleaning control unit 74 moves the head 10 to the retracted position when the wiper 61 passes directly below the protruding portion 41a. For this reason, when the wiper 61 soiled by the last wiping operation passes below the cap 40, the wiper 61 does not come into contact with the cap 40, so that the dirt on the wiper 61 does not move to the cap 40.

  In the cleaning operation, the head position adjustment unit 74a moves the head 10 to the retracted position, and the wiper movement control unit 74b wipes the wiper 61 until just before the wiper movement control unit 74b passes below the protrusion 41a and is positioned below the cleaning member 65. Then, the head position adjustment unit 74a moves the head 10 to the wiping position, and the wiper movement control unit 74b moves the wiper 61 in the wiping direction until it passes under the cleaning member 65. This simplifies the configuration for sliding the wiper 61 against the cleaning member 65.

  Further, when the head 10 is disposed at the wiping position, the lower end of the protruding portion 65a of the cleaning member 65 is positioned below the discharge surface 10a. Dirt that is rubbed and adhered to the wiper 61 can be cleaned extensively. As a result, the number of cleaning operations can be reduced.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims.

  For example, in the above-described embodiment, the cleaning operation of the wiper 61 is started when the count number of the maintenance frequency counter 73a is 10,000 or more and the count number of the print number counter 73b is 350,000 or more. However, each threshold for determining whether or not to start the cleaning operation may be an arbitrary value as long as it is a number of 2 or more. In addition, the count number of the maintenance count counter 73a and the print count counter 73b is reset every time the cleaning operation is started, but at least one of the count count of the maintenance count counter 73a and the print count counter 73b is set to zero. A configuration that does not reset may be used. In this case, it is only necessary to have a plurality of threshold values for determining whether or not to start the cleaning operation. As for this threshold value, the minimum value may be 2 or more, and the difference between adjacent threshold values may be 2 or more.

  In the above-described embodiment, the movement speed of the wiper 61 in the cleaning operation is slower than the movement speed of the wiper 61 in the wiping operation. However, the movement speed of the wiper 61 in the cleaning operation is the same as that in the wiping operation. It may be higher than the moving speed of the wiper 61.

  Furthermore, in the above-described embodiment, the impurity scraped off by the cleaning member 65 is collected by the impurity tray 66 disposed below the cleaning member 65. However, any means for collecting the scraped impurity can be used. May be. For example, a suction mechanism for sucking impurities may be disposed in the vicinity of the cleaning member 65.

  In addition, in the above-described embodiment, the discharge amount related to the purge operation when the cleaning operation is performed next is larger than the discharge amount related to the purge operation when the cleaning operation is not performed next. The discharge amount related to the purge operation when the cleaning operation is performed next may be equal to or less than the discharge amount related to the purge operation when the cleaning operation is not performed next.

  In the above embodiment, the cleaning member 65 and the ejection surface 10a of the head 10 adjacent to the cleaning member 65 are arranged on the same straight line as viewed from above, but the ejection surface 10a of the head 10 adjacent to the cleaning member 65 and The positional relationship may be arbitrary.

  Further, in the above-described embodiment, in the cleaning operation, the wiper 61 is positioned below the cleaning member 65 by passing below the protruding portion 41a with the cleaning control unit 74 moving the head 10 to the retracted position. After moving in the wiping direction until just before, the head 10 is moved again to the wiping position, and then the wiper 61 is moved so that the wiper 61 is cleaned by the cleaning member 65. The wiper 61 is moved in the wiping direction. In the process of moving, the position of the head 10 may not be moved. In this case, it is preferable that the wiper 61 does not come into contact with the cap, or the printer has a means for cleaning the cap.

  Further, when the head 10 is disposed at the wiping position, the lower end of the protrusion 65a of the cleaning member 65 is positioned below the discharge surface 10a in the direction orthogonal to the discharge surface 10a. As long as 61 is in a range that can contact the cleaning member 65, the lower end of the protrusion 65 a of the cleaning member 65 may be above the discharge surface 10 a or may be at the same position as the discharge surface 10 a.

  In the above-described embodiment, the cleaning member 65 is configured to have the protruding portion 65a protruding downward, and the protruding portion has a hanging portion that hangs downward, and a horizontal portion that protrudes upstream from the hanging portion in the wiping direction. , May be configured. The upstream end of the horizontal portion rubs against the wiper 61, and the scraped foreign matter accumulates on the upper surface of the horizontal portion. If the horizontal portion is disposed below the discharge surface 10a, the wiper 61 can be cleaned in a wide range. Further, it is not necessary to provide a tray or the like for storing the scraped foreign matter, which contributes to downsizing of the apparatus.

  The present invention can be applied to both a line type and a serial type, and is not limited to a printer, and can also be applied to a facsimile, a copier, and the like. Furthermore, liquids other than ink may be ejected.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 1p Controller 3 Head holder 7 Reverse mechanism 8 Glass table 8a Surface 9 Platen 10 Head 10a Discharge surface 14a Discharge port 40 Cap 41a Protrusion part 42 Movable body 44 Lip raising / lowering motor 50 Humidification mechanism 53 Pump 60 Wiper movement mechanism 61 Wiper 63 Wiper moving motor 65 Cleaning member 65a Protruding portion 66 Impurity tray 68 Holder raising / lowering motor 69 Purge pump 71 Head control unit 72 Maintenance control unit 73a Maintenance frequency counter 73b Print number counter 74 Cleaning control unit 74a Head position adjustment unit 74b Wiper movement control unit

Claims (9)

A liquid ejection head having an ejection surface on which ejection ports for ejecting liquid are disposed;
A forced discharge mechanism for forcibly discharging liquid from the discharge port;
With wiper,
A wiper moving mechanism for moving the wiper so that the discharge surface is wiped away;
A cleaning member that cleans the wiper by contacting the wiper;
Control means for controlling the liquid discharge head, the forced discharge mechanism and the wiper moving mechanism,
The control means includes
Maintenance control means for controlling the forced discharge mechanism and the wiper moving mechanism so that a maintenance operation for sequentially performing the forced discharge and the wiping is performed;
A maintenance frequency counter for counting the number of times the maintenance operation has been performed;
Liquid has been discharged to two or more recording media since the wiper was finally cleaned, and the count value of the maintenance counter is one or more thresholds (minimum value is 2 or more and the threshold is And a cleaning control means for controlling the wiper moving mechanism so that the cleaning is performed only when the difference between the threshold values adjacent to each other is 2 or more). Liquid ejecting device.   The said cleaning control means controls the said wiper moving mechanism so that the moving speed of the said wiper at the time of the said cleaning may become slower than the moving speed of the said wiper at the time of the said wiping. Liquid discharge device.   The liquid ejection apparatus according to claim 1, wherein an impurity tray is disposed below the cleaning member.   The maintenance control means controls the forced discharge mechanism so that a liquid discharge amount related to the forced discharge immediately before the cleaning is performed is larger than a liquid discharge amount related to the other forced discharge. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus.   The liquid ejection apparatus according to claim 1, wherein the cleaning member and the ejection surface are arranged on the same straight line. An elevating mechanism for elevating and lowering the liquid ejection head in a direction orthogonal to the ejection surface;
An annular lip member made of an elastic member and surrounding the liquid discharge head; and a cap member made of an elastic member and having a diaphragm connecting the lip member and the liquid discharge head.
The elevating mechanism can arrange the liquid discharge head at a retracted position where the wiper and the cap member are separated from each other in a direction orthogonal to the discharge surface.
The cleaning control unit controls the lifting mechanism to dispose the liquid discharge head at the retracted position when the wiper passes below the cap member after wiping of the discharge surface is completed. 6. The liquid ejection apparatus according to claim 1, further comprising an arrangement changing unit. A facing member facing the discharge surface across a discharge space facing the discharge surface;
A lip moving mechanism that moves the lip member between a contact position where the lip member contacts the opposing member and a separation position separated from the opposing member;
The elevating mechanism raises and lowers the liquid ejection head integrally with the cleaning member, and forms an image on the recording medium with respect to the retreat position and a direction perpendicular to the ejection surface. It can be arranged at any of the recording position and the wiping position below the recording position and the wiper abuts to wipe the discharge surface,
The maintenance control means controls the wiper moving mechanism and the elevating mechanism in a state where the lip member is moved to the separation position by the lip moving mechanism, and arranges the liquid discharge head at the wiping position. , Wipe the discharge surface with the wiper,
The cleaning control means controls the elevating mechanism to control the second arrangement changing means for arranging the liquid ejection head at the wiping position, and the wiper moving mechanism to pass the lower part of the lip member. The liquid ejecting apparatus according to claim 6, further comprising a rubbing control unit that rubs the wiper against the cleaning member.   The liquid ejection apparatus according to claim 7, wherein a leading end of the cleaning member on which the wiper is rubbed with respect to a direction orthogonal to the ejection surface is positioned below the ejection surface. The liquid discharge head for discharging ink onto a recording medium;
A pretreatment liquid that acts on the ink to agglomerate or deposit components in the ink, and includes the liquid discharge head provided upstream in the transport direction of the recording medium from the liquid discharge head that discharges the ink. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus.

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