JP2013248850A - Liquid discharging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent liquid near the discharging ports from being dried so as to suppress liquid discharging for flushing or the like that is performed to prevent the liquid from being dried.SOLUTION: A printer includes: a head 10 that discharges an ink; a capping mechanism 40; a humidifying mechanism 50; and a control unit. The humidifying mechanism 50 has an opposite member 51 equipped with a cylindrical member 61, in which through-holes opposed to discharging ports are formed. The control unit controls the humidifying mechanism 50 so that the humidifying mechanism 50 performs humidifying operation, in which humidifying air is supplied from the through-holes toward the discharging ports, when the capping mechanism 40 is in an open state and a paper sheet P is not opposed to the discharging ports.

Description

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

  In Patent Document 1, when the head is not used (when the head is at rest), the space (discharge space) facing the discharge port is isolated from the external space (surrounding space) (after capping), and the space is humidified. A liquid ejection device is described. This humidification maintenance is performed by discharging air in the discharge space from the air discharge port and supplying humidified air from the air supply port to the discharge space.

JP 2011-207091 A

  By the way, when the head is not capped, the discharge port is exposed to the external space. For this reason, the liquid at the discharge port is dried. Even when the head is in use (when recording an image on a recording medium), for the ejection port where ink is not ejected, the liquid in the ejection port is dried according to the time since the head was uncapped. To do. For the purpose of suppressing drying of these discharge ports, a technique for performing flushing for discharging ink from the discharge ports is known. However, when such flushing is performed, there is a problem that the amount of liquid consumption increases.

  Accordingly, an object of the present invention is to provide a liquid ejection device capable of suppressing the drying of the liquid near the ejection port.

  The liquid ejection apparatus according to the present invention includes a head having an ejection port for ejecting liquid, a transport mechanism for transporting a recording medium to a position facing the ejection port, and an ejection space facing the ejection port around the ejection space. A cap mechanism capable of taking a partitioned state partitioned with respect to the space and an open state in which the discharge space is opened with respect to the surrounding space; and a counter member facing the discharge port, on the surface of the counter member A humidifying mechanism that performs humidifying operation for supplying humidified air to the discharge port from the formed opening, and the cap mechanism takes the open state, and the humidifying operation is performed when the recording medium is not opposed to the discharge port. And a control means for controlling the humidifying mechanism.

  According to this, the opening facing the discharge port is formed in the facing member. When the recording medium is in an open state and does not face the ejection port, humidified air is supplied from the opening toward the ejection port. For this reason, drying of the liquid in the vicinity of the discharge port is suppressed. As a result, liquid discharge due to flushing or the like performed to suppress drying can be suppressed.

  In the present invention, it is preferable that the facing member supports the recording medium conveyed to a position facing the ejection port on the surface. This eliminates the need to provide a support member for supporting the recording medium separately from the opposing member.

  In the present invention, the humidification mechanism includes supply means for performing the humidification operation, and suction means for performing a suction operation for sucking air in the discharge space from the opening. The control unit controls the supply unit to perform the humidifying operation when the recording medium is not facing the ejection port, and when the recording medium is opposed to the ejection port, It is preferable to control the suction means so as to perform a suction operation. Thereby, when the recording medium faces the ejection port, the recording medium can be reliably supported on the surface of the facing member. For this reason, the gap (gap) between the recording medium and the ejection port is stabilized, and the quality of the image formed on the recording medium can be maintained.

  Further, in the present invention, a plurality of the openings are formed on the surface of the facing member, and the supply means supplies humid air from a part of the openings, and the suction The means sucks air from the openings other than the part, and the control means performs the humidifying operation and the sucking operation when the recording medium faces the ejection port. It is preferable to control the suction means. Accordingly, when the recording medium faces the ejection port, the recording medium can be reliably supported by the surface of the facing member, and humidified air can be supplied to the back surface of the recording medium. Become. For this reason, curling of the recording medium can be suppressed while maintaining the image quality.

  In the present invention, the supply unit and the suction unit are configured by a common mechanism. The control means performs only the suction operation when the recording medium faces the ejection port so that only the humidification operation is performed when the recording medium does not face the ejection port. Preferably, the supply means and the suction means are controlled so as to be performed. This simplifies the configuration of the humidifying mechanism.

  In the present invention, it is preferable that the control unit controls the humidification mechanism so that the humidification operation is performed even when a recording medium faces the ejection port. This makes it possible to supply humidified air to the back surface of the recording medium. For this reason, the difference in moisture between the front surface and the back surface of the recording medium is reduced, and the recording medium is less likely to curl.

  In the present invention, the control means may supply a supply amount of humidified air toward the recording medium as the amount of liquid discharged to the recording medium increases from a predetermined amount based on the received recording command. It is preferable to control the humidification mechanism so as to increase. Thereby, curling of the recording medium can be effectively suppressed.

  In the present invention, the facing member includes a cylindrical member whose axis extends in a direction perpendicular to the conveyance direction of the recording medium and is rotatably supported, and the opening is formed on a side surface of the cylindrical member. It is preferable that Thereby, the conveyance load of the recording medium is reduced.

  Moreover, in this invention, it is preferable that the said opposing member further contains the receiving part arrange | positioned in the position which pinches | interposes the said cylindrical member between the said discharge ports. As a result, it is possible to receive the moisture that has dropped from the cylindrical member on the side opposite to the head by the receiving portion, and the moisture does not leak into the apparatus.

  Further, in the present invention, a concave portion in which the cylindrical member is disposed is formed in a plane facing the discharge port of the receiving portion, and a portion closest to the discharge port of the cylindrical member is the receiving portion. It is preferable to arrange at the same height level as the plane. As a result, the recording medium can be supported by the cylindrical member and the receiving portion. For this reason, the gap between the recording medium and the ejection port becomes more stable.

  According to the liquid ejection apparatus of the present invention, the facing member is formed with an opening facing the ejection port. When the recording medium is in an open state and does not face the ejection port, humidified air is supplied from the opening toward the ejection port. For this reason, drying of the liquid in the vicinity of the discharge port is suppressed. As a result, liquid discharge due to flushing or the like performed to suppress drying can be suppressed.

1 is a schematic side view showing an internal structure of an ink jet printer according to an embodiment of a liquid ejection apparatus of the present invention. It is a top view which shows the head main body of the head contained in the printer of FIG. (A) is the enlarged view which shows the area | region IIIa enclosed with the dashed-dotted line of FIG. 2, (b) is a fragmentary sectional view along the IIIb-IIIb line | wire of FIG. 3 (a), (c) is a figure. It is an enlarged view which shows the area | region IIIc enclosed with the dashed-dotted line of 3 (b). It is the schematic which shows the cap mechanism contained in the printer of FIG. It is the schematic which shows the humidification mechanism contained in the printer of FIG. It is a perspective view of the opposing member shown in FIG. (A) is a perspective view of the cylindrical member shown in FIG. 6, (b) is a perspective view of the inner cylinder of a cylindrical member. (A) is the fragmentary sectional view which followed the VIIIa-VIIIa line of FIG. 6, (b) is the fragmentary sectional view which followed the VIIIb-VIIIb line of FIG.7 (b). It is a functional block diagram of the control apparatus shown in FIG. In the printer shown in FIG. 1, the operation state of the humidifying mechanism when the image recording operation is being executed is shown, (a) is a diagram showing a state in which humidified air is supplied toward the discharge surface, FIG. 6B is a diagram illustrating a state where the paper P is sucked and humidified air is supplied.

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

  First, an overall configuration of an ink jet printer 101 which is an embodiment of the liquid ejection apparatus of the present invention will be described with reference to FIG.

  The printer 101 has a rectangular parallelepiped housing 101a. A paper discharge unit 31 is provided on the top plate of the housing 101a. The internal space of the housing 101a can be divided into spaces A, B, and C in order from the top. In the spaces A and B, a paper transport path from the paper feed unit 101c to the paper discharge unit 31 is formed. In the space A, image recording on the paper P and conveyance of the paper P to the paper discharge unit 31 are performed. In the space B, the paper P is fed to the conveyance path. From the space C, ink is supplied to the inkjet head 10 in the space A (hereinafter referred to as the head 10).

  In the space A, a head 10 for discharging black ink, a paper sensor 32, a transport mechanism 8, a cap mechanism 40, a humidifying mechanism 50 used for a humidifying operation and a suction operation, a control device 100, and the like are arranged.

  The head 10 has a long, substantially rectangular parallelepiped shape with the main scanning direction as the longitudinal direction (see FIG. 2). The head 10 is supported by the housing 101a via a support frame (not shown). The support frame holds the head 10 so that a predetermined gap suitable for recording is formed between the lower surface of the head 10 and a facing member 51 (described later). The head 10 is a laminated body in which a reservoir unit, a flexible printed circuit board (FPC), a circuit board, and the like are laminated in addition to the head body 3 (see FIG. 2). An upstream ink flow path (both not shown) including a reservoir is formed in the reservoir unit as the upstream flow path member, and ink is supplied from the cartridge 4.

  The flow path unit 9 as a downstream flow path member constitutes the head body 3 together with the actuator unit 121, and ink of the reservoir unit is supplied from the ink supply port 105b on the upper surface. The lower surface of the flow path unit 9 is a discharge surface 10a, and a plurality of discharge ports 108 are formed. Ink is ejected from the ejection port 108 by driving the actuator unit 121.

  The circuit board adjusts a signal from the control device 100. The output signal is converted into a drive signal by a driver IC on the FPC, and further output to the actuator unit 121 of the head body 3. When the drive signal is supplied, the actuator unit 121 is deformed and applies pressure to the ink in the flow path unit 9. The head 10 will be described in detail later.

  The transport mechanism 8 includes two guide portions 9a and 9b that guide the paper P. The two guide portions 9a and 9b are arranged with the opposing member 51 interposed therebetween. The guide portion 9a on the upstream side in the transport direction includes three guides 18a and three feed roller pairs 22 to 24, and connects the paper feed portion 101c and the opposing member 51. Then, the guide portion 9 a conveys the image recording paper P toward the facing member 51. The guide portion 9 b on the downstream side in the transport direction has three guides 18 b and four feed roller pairs 25 to 28, and connects the facing member 51 and the paper discharge portion 31. The paper P after image recording is conveyed toward the paper discharge unit 31.

  The paper sensor 32 is arranged on the upstream side in the transport direction of the pair of feed rollers 24 and detects the front end and the rear end of the transported paper P. A detection signal output when the front edge and the rear edge of the paper P are detected is used for the start and end timings of a suction operation described later. The detection signal output when the front edge of the paper P is detected is also used to drive the synchronized head 10 and the transport mechanism 8, and an image is recorded on the paper P at a desired resolution and speed.

  In the space B, the paper feeding unit 101c is arranged. The paper feed unit 101 c includes a paper feed tray 20 and a paper feed roller 21. Among these, the paper feed tray 20 is detachable from the housing 101a. The paper feed tray 20 is a box that opens upward, and stores a plurality of papers P. The paper feed roller 21 sends out the uppermost paper P in the paper feed tray 20.

  Here, the sub-scanning direction is a direction parallel to the transport direction D (direction of arrow D in FIG. 1) in which the paper P is transported by the feed roller pairs 23 to 25, and the main scanning direction is parallel to the horizontal plane and This is a direction orthogonal to the sub-scanning direction.

  In the space C, a cartridge 4 that stores black ink is detachably attached to the housing 101a. The cartridge 4 is connected to the head 10 via a tube (not shown), and supplies ink to the head 10.

  Next, the control device 100 will be described. The control device 100 controls the operation of each part of the printer and controls the operation of the entire printer 101. For example, the control device 100 controls an image recording operation, a maintenance operation, and the like. The image recording operation is performed based on a recording command (image data or the like) supplied from an external device (such as a PC connected to the printer 101). When the recording command is input, the control device 100 drives the paper feeding unit 101c, the guide units 9a and 9b (conveying mechanism 8), and the humidifying mechanism 50. The paper P sent out from the paper feed tray 20 is guided by the upstream guide portion 9 a and sent onto the facing member 51. As will be described later, the sheet P is transported in the transport direction D while being sucked by the facing member 51 and passes directly below the head 10. At this time, ink is ejected from the ejection surface 10 a by the control of the control device 100, and a desired image is recorded on the paper P. Further, the paper P on which the image is formed is guided by the downstream guide portion 9b and discharged from the upper portion of the housing 101a to the paper discharge portion 31.

  In addition, as the maintenance operation, an ink discharging operation (purge operation and flushing operation), a capping and uncapping operation, a humidifying operation, and the like are performed periodically or in response to a user request. Both are aimed at maintaining / recovering the ink ejection characteristics of the head 10.

  For example, in the ink discharging operation, the thickened ink is discharged from the ejection port 108. In the purge operation, pressure is applied by driving the pump without driving the actuator, and ink is forcibly discharged from the head 10. After the forced discharge, the discharge surface 10a is cleaned. In the flushing operation, the actuator is driven and a predetermined amount of ink droplets are ejected from the head 10. Actuator driving is based on flushing data (data different from image data).

  In the capping operation, as shown in FIG. 4B, the cap member 41 of the cap mechanism 40 sets the discharge space (the space facing the discharge surface 10a) S1 from the surrounding space S2. Thereby, drying of the ink in the ejection port 108 is suppressed. In the uncapping operation, as shown in FIG. 4A, the cap member 41 opens the discharge space S1 with respect to the surrounding space S2. As a result, the recording on the paper P is enabled. The capping operation is performed, for example, when the image recording operation is paused or when the printer 101 is turned off. The uncapping operation is performed, for example, when a recording command is received.

  There are first and second humidifying operations in the humidifying operation. In the first humidification operation, when the head 10 is in an open state, humidified air is supplied to the discharge space S1. In the second humidification operation, when the head 10 is in the partitioned state, humidified air is supplied to the ejection space S1 for a predetermined time. As a result, it is possible to suppress drying of the ink in the vicinity of the ejection port 108.

  Next, the head body 3 of the head 10 will be described in detail with reference to FIGS. In FIG. 3A, for convenience of explanation, the pressure chamber 110 and the discharge port 108 that are to be drawn with broken lines below the actuator unit 121 are drawn with solid lines.

  As shown in FIG. 2, the head body 3 is a laminated body in which four actuator units 121 are fixed to the upper surface 9 a of the flow path unit 9. On the upper surface 9a, as shown in FIG. 3A, a plurality of pressure chambers 110 are opened and arranged in a matrix. As shown in FIG. 3C, each actuator unit 121 seals these openings and constitutes a side wall of the pressure chamber 110.

  As shown in FIG. 3B, the flow path unit 9 is a laminated body in which nine stainless plates 122 to 130 are laminated. An ink flow path is formed inside the flow path unit 9. As shown in FIG. 2 and FIG. 3, the ink flow path has one end of the ink supply port 105b on the upper surface 9a and a pressure from the manifold flow path 105 branched to the sub-manifold flow path 105a and the outlet of the sub-manifold flow path 105a. An individual ink flow path 132 that reaches the discharge port 108 on the lower surface through the chamber 110 is included. On the discharge surface 10 a, a plurality of discharge ports 108 are arranged in a matrix corresponding to the pressure chambers 110. The ejection ports 108 are arranged at intervals of 600 dpi, which is the resolution in this direction, with respect to the main scanning direction.

  Next, the actuator unit 121 will be described. As shown in FIG. 2, the four actuator units 121 each have a trapezoidal planar shape. These four actuator units 121 are arranged in a staggered pattern along the main scanning direction so as to avoid the ink supply port 105b.

  The actuator unit 121 is a ferroelectric lead zirconate titanate (PZT) ceramic, and is composed of three piezoelectric layers 141 to 143 as shown in FIG. The uppermost piezoelectric layer 141 has a plurality of individual electrodes 135 formed on its upper surface and is polarized in the thickness direction. As for the piezoelectric layer 142, the common electrode 134 is formed in the upper surface entirely. A portion sandwiched between the individual electrode 135 and the pressure chamber 110 functions as an individual unimorph actuator. When an electric field in the polarization direction is generated between the individual electrode 135 and the common electrode 134, the actuator portion protrudes toward the pressure chamber 110 (unimorph deformation). At this time, the ink in the pressure chamber is pressurized and ink droplets are ejected from the ejection port 108. Here, the common electrode 134 is always at the ground potential. Further, the drive signal is selectively supplied to the individual electrode 135.

  In the present embodiment, a striking method is employed when ink is ejected. The individual electrode 135 is at a predetermined potential in advance, and the actuator is unimorph deformed. When the drive signal is supplied, the individual electrode 135 once has the same potential as the common electrode 134 and returns to the predetermined potential after a predetermined time. At the same potential, the actuator eliminates unimorph deformation and ink is sucked into the pressure chamber 110. At the return timing of the potential, the actuator is deformed again by unimorph, and an ink droplet is ejected from the ejection port 108.

  Next, the cap mechanism 40 will be described with reference to FIG. The cap mechanism 40 includes a cap member 41, a cap lifting mechanism 47, and a counter member 51. The cap member 41 includes a lip member 42, a diaphragm 43 and a mounting portion 44 that are integrally formed, and a holder 45. The lip member 42, the diaphragm 43, and the attachment portion 44 are made of an elastic material such as rubber (for example, butyl rubber). The diaphragm 43 and the attachment portion 44 block between the lip member 42 and the flow path unit 9.

  The lip member 42 is formed in an annular shape and surrounds the periphery of the flow path unit 9. The lip member 42 has a cross-sectional shape that tapers downward. The attachment portion 44 is also formed in an annular shape, and surrounds the flow path unit 9 over the entire circumference. As shown in FIG. 4, the attachment portion 44 is fixed to the upper end of the side surface of the flow path unit 9.

  The diaphragm 43 is formed in an annular shape, and is stretched between the lip member 42 and the flow path unit 9. More specifically, the diaphragm 43 is a thin film member having flexibility, the outer peripheral end is connected to the inner peripheral surface of the lip member 42, and the inner peripheral end is connected to the lower surface of the mounting portion 44. . As a result, the gap between the lip member 42 and the flow path unit 9 is closed. The holder 45 is made of an annular rigid material (for example, stainless steel) and is fixed to the upper surface of the lip member 42.

  The facing member 51 includes a support portion 52 having a rectangular parallelepiped shape. The upper surface 52a of the support portion 52 is a plane parallel to the ejection surface 10a, and the plane size is slightly larger than the cap member 41. For this reason, when the lip member 42 is disposed at a contact position (described later), the lip member 42 contacts the peripheral edge portion of the upper surface 52a. Details of the facing member 51 will be described later.

  The cap lifting mechanism 47 has a plurality of gears 48 and a lifting motor 49 (see FIG. 9). The plurality of gears 48 are connected to the holder 45. When the lift motor 49 is driven under the control of the control device 100, the gear 48 rotates and the holder 45 moves up and down. At this time, the lip member 42 also moves up and down. Thereby, the relative position of the front-end | tip of the lip member 42 and the discharge surface 10a changes to a perpendicular direction.

  The tip of the lip member 42 is brought into contact with the upper surface 52a of the support portion 52 as the holder 45 is moved up and down (the position shown in FIG. 4B), and is separated from the upper surface 52a (see FIG. The position shown in a) is selectively taken. The contact position is a position where the lip member 42 can contact the support portion 52. When the lip member 42 comes into contact with the upper surface 52a, the discharge space S1 is partitioned from the surrounding space S2 by the cap member 41, the discharge surface 10a, and the facing member 51. Further, at the separation position, the discharge space S1 is opened from the surrounding space S2.

  Next, the structure of the humidification mechanism 50 is demonstrated below, referring FIGS. As shown in FIG. 5, the humidifying mechanism 50 includes a facing member 51, pipes 54 to 56, a supply pump 57, a suction pump 58, a tank 59, and the like. As shown in FIG. 6, the facing member 51 includes a support part (receiving part) 52 and a cylindrical member 61. A concave portion 52b extending in the main scanning direction is formed at the center of the support portion 52. The recessed part 52b is opened facing the discharge surface 10a and accommodates the cylindrical member 61 in a rotatable manner. The upper end surface of the cylindrical member 61 is at the same height level as the upper surface 52a of the support portion 52 in the vertical direction.

  As shown in FIG. 7A and FIG. 8A, the cylindrical member 61 is a double cylindrical body in which an inner cylinder 62 and an outer cylinder 63 are coaxial. Among them, both end portions of the inner cylinder 62 extend from the outer cylinder 63 on both sides in the longitudinal direction and are supported by the support portion 52. The outer cylinder 63 rotates integrally with the inner cylinder 62. As shown in FIG. 6, with respect to the main scanning direction, the inner cylinder 62 has the same length as the support portion 52, and the outer cylinder 63 is slightly shorter than the recess 52b.

  The inner cylinder 62 is a dispersion member for humidified air, and humidified air is supplied from the outside. As shown in FIG. 7B, the inner cylinder 62 includes a cylinder body 64 that is open at one end and closed at the other end, a ring 65, and a lid body 66. As shown in FIGS. 7B and 8, the cylindrical body 64 has a plurality of protruding portions 64 a formed on the outer peripheral side surface. These projecting portions 64a project from the outer peripheral side surface in the radial direction, and constitute four projecting portion rows side by side in the main scanning direction. Each protrusion part row | line | column is arrange | positioned at equal intervals in the circumferential direction. A through hole 64 b is formed in the projecting portion 64 a and communicates with the internal space of the inner cylinder 62. As shown in FIG. 7B, each protrusion 64a is long in the main scanning direction, and the through hole 64b is the same.

  The cross-section of the ring 65 has the same shape and the same size as the cylindrical body 64, and is rotatably supported by the cylindrical body 64 at one end of the cylindrical body 64. As shown in FIG. 8B, a communication pipe 65 a is arranged on the ring 65. One end of a pipe 55 is connected to the communication pipe 65a, and the inner cylinder 62 and the pipe 55 communicate with each other. The lid 66 is fixed to the ring 65 and closes the opening of the ring 65 on the side opposite to the cylindrical body 64. Thus, the humidified air is supplied from the pipe 55 to the internal space of the inner cylinder 62 through the communication pipe 65a, and is uniformly distributed from the through hole 64b to the outside.

  In the present embodiment, the outer cylinder 63 is an outside air suction member and also serves as a humidifying air scattering member. As shown in FIG. 7A and FIG. 8A, the outer cylinder 63 includes a cylindrical body 68 that is open at both ends and two rings 67. The cylindrical body 68 has a plurality of through holes (openings) 63a and 63b formed on the outer peripheral side surface. The numbers are equal to each other. On the outer peripheral side surface, four through-hole rows 63A and 63B are arranged side by side in the main scanning direction. The through-hole rows 63A and 63B are arranged alternately and at equal intervals in the circumferential direction. The through hole 63a communicates with a gap (between the inner cylinder 62 and the outer cylinder 63) formed by both the cylinders 64 and 68, and the through hole 63b communicates with the internal space of the inner cylinder 62 through the through hole 64b. ing. At this time, the front end surface of the projecting portion 64 a is fixed to the inner surface of the cylindrical body 68 at the connection portion between the through hole 63 b and the through hole 64 b.

  The two rings 67 are rotatably arranged at both ends of the cylinder body 68 (outer cylinder 63) and the cylinder body 64 (inner cylinder 62) to close the gap. The ring 67 does not hinder the integral rotation of the inner cylinder 62 and the outer cylinder 63. An L-shaped joint is attached to the ring 67 on the ring 65 side of the inner cylinder 62. One end side of the joint is connected to a through-hole penetrating the ring 67 in the main scanning direction, and the other end side is connected to a pipe 56. The through hole opens in the gap. Thereby, if the piping 56 is sucked, outside air (air in the discharge space S1) flows from the through hole 63a toward the joint. Outside air is drawn almost evenly into each through-hole 63a.

  The pipes 54 and 55 constitute a supply system (supply means) of humidified air together with the supply pump 57 and the tank 59 in addition to the cylindrical member 61. As shown in FIG. 5, the pipe 54 has one end connected to the tank 59 and the other end open to the atmosphere. The pipe 55 connects the inner cylinder 62 and the tank 59. A supply pump 57 is provided in the middle of the pipe 55. The tank 59 stores humidification water in the lower space, and stores humidified air in the upper space. The pipe 54 communicates with the lower space (underwater) of the tank 59, and the pipe 55 communicates with the upper space of the tank 59. Note that a check valve (not shown) is attached to the pipe 54 so that water in the tank 59 does not flow into the pipe 54, and air flows only in the direction of the white arrow in FIG. In addition to the cylindrical member 61, the pipe 56 constitutes an outside air suction system (suction means) together with the suction pump 58. One end of the pipe 56 is connected to the ring 67. A suction pump 58 is provided in the middle of the pipe 56, and the other end is open to the atmosphere.

  In this configuration, when the supply pump 57 is driven under the control of the control device 100, air flows in the direction of the white arrow in FIG. That is, a negative pressure is generated in the upper space of the tank 59 by the supply pump 57, and air is drawn into the lower space of the tank 59 from the pipe 54. When this air passes through the water, humid air is generated in the upper space. The humid air in the upper space flows into the inner cylinder 62 through the pipe 55 and is discharged from the through hole 63b. The discharged humidified air is directed to the discharge port 108 (discharge surface 10a) if there is no paper P on the cylindrical member 61. Water is supplied to the ink in the vicinity of the ejection port 108. If the paper P is on the cylindrical member 61, the back surface of the paper P is humidified. When an image is formed on the surface of the paper P, the curling phenomenon of the paper P is suppressed.

  When the suction pump 58 is driven under the control of the control device 100, air flows in the direction of the thick black arrow in FIG. That is, air is discharged from the other end of the pipe 56 by the suction pump 58, and a negative pressure is generated in the gap between the inner cylinder 62 and the outer cylinder 63. According to the negative pressure, outside air is sucked into the gap from the through hole 63a. At this time, if there is a sheet P on the cylindrical member 61, the sheet P is attracted to the opposing member 51 side, and the floating phenomenon during conveyance is suppressed.

  Next, the control device 100 will be described with reference to FIG. The control device 100 includes a CPU (Central Processing Unit), a program executed by the CPU and a ROM (Read Only Memory) that stores data used in these programs in a rewritable manner, and temporarily stores data when the program is executed. RAM (Random Access Memory). Each functional unit constituting the control device 100 is constructed by cooperation of these hardware and software in the ROM. As illustrated in FIG. 9, the control device 100 includes a conveyance control unit 151, an image data storage unit 152, a head control unit 153, and a maintenance control unit 154.

  The conveyance control unit 151 is configured so that the paper P is conveyed at a predetermined speed along the conveyance direction based on the recording command received from the external device, and the suction pump 58. Control each operation. The image data storage unit 152 stores image data included in a recording command from an external device. The head controller 153 controls the head 10 so that an image is recorded on the paper P based on the image data.

  The maintenance control unit 154 controls driving of the lifting motor 49 when performing capping and uncapping operations. The maintenance control unit 154 controls driving of the supply pump 57 when performing the first humidification operation. At this time, the maintenance control unit 154 increases the supply amount of humidified air per unit time from the reference amount as the amount of ink ejected onto the paper P based on the current image data increases from a predetermined amount. The rotation speed of the supply pump 57 is increased so as to increase. When the amount of ink ejected onto the paper P is less than a predetermined amount, a reference amount of humidified air is supplied. The maintenance control unit 154 controls driving of the supply pump 57 when performing the second humidification operation. At this time, the maintenance control unit 154 drives the supply pump 57 for a predetermined time, with the supply amount of humidified air per unit time being a reference amount.

Next, a series of flow of the image recording operation of the printer 101 will be described.
When the printer 101 receives the recording command, the image data is stored in the image data storage unit 152. At this time, the maintenance control unit 154 starts the first humidification operation. First, the maintenance control unit 154 calculates an ink amount necessary for image formation from the image data. Furthermore, since the supply amount of humidified air corresponding to the ink amount (drive rotation speed of the supply pump 57) is set, the maintenance control unit 154 starts driving the supply pump 57 at the set rotation speed. From each through hole 63b, a desired amount of humidified air is supplied toward the discharge surface 10a (that is, the discharge space S1). If the through hole 63b faces the discharge surface 10a, the humidified air goes directly to the discharge surface 10a across the discharge space S1. If the through hole 63b faces the wall surface of the recess 52b, the humidified air once hits the wall surface. As shown in FIG. 10A, the recess 52b has a U-shaped cross section and the opening faces the discharge surface 10a. Therefore, the humidified air flows along the wall surface and smoothly moves toward the discharge surface 10a.

  At this time, the conveyance control unit 151 drives the sheet feeding unit 101c, the guide units 9a and 9b, and the suction pump 58. Thereby, the conveyance of the paper P starts. The leading edge and the trailing edge of the sheet P are detected by the sheet sensor 32 during the conveyance. Based on the front and rear end detection signals, the transport control unit 151 controls the driving of the suction pump 58. When the conveyance control unit 151 receives the leading edge detection signal, the conveyance control unit 151 starts the suction pump 58 after a predetermined time depending on the positional relationship between the paper sensor 32 and the cylindrical member 61. At this time, the leading end of the paper P faces the cylindrical member 61. Further, when receiving the trailing edge detection signal, the conveyance control unit 151 stops the suction pump 58 after a predetermined time. At this time, the rear end portion of the paper P faces the cylindrical member 61. Thus, only when the paper P faces the cylindrical member 61 (when facing the ejection port 108), external air is sucked from the four rows of through holes 63a (suction operation). In the suction ON / OFF control, at least the suction force at the start of suction may be made stronger than at other times. As a result, the sheet P entering the image forming area can be surely copied to the upper surface 52 a of the support portion 52. It is effective for jam prevention.

  When the suction operation is executed, the paper P is sucked toward the cylindrical member 61 as shown in FIG. At this time, the region facing the ejection surface 10 a of the paper P is supported on the outer peripheral side surface of the cylindrical member 61 following the upper surface 52 a of the support portion 52. The gap (gap) between the paper P and the ejection surface 10a is constant. As a result, ink landing accuracy is improved and image quality can be maintained. In addition, even if the paper P is adsorbed by the cylindrical member 61, the conveyance of the paper P is not hindered. Since the paper P is easily separated from the cylindrical member 61 by the rotation of the cylindrical member 61, the conveyance load and its fluctuation are small. Jam is also prevented.

  When the paper P is at a position facing the cylindrical member 61, humidified air is supplied to the back surface of the paper P. The curl phenomenon is caused by a difference in water supply amount between the front and back sides of the paper P. Humidification (moisture supply) on the back side reduces this difference. In this embodiment, since the supply amount of humidified air is adjusted according to the ink discharge amount at the time of image formation, moisture can be supplied to the back surface without excess or deficiency. As a result, curling can be effectively suppressed. At this time, the suction force with respect to the paper P by the through hole 63a is set so that the paper P does not float from the upper surface 52a to the ejection surface 10a side by the supply of humidified air.

  The head controller 153 forms an image in synchronization with the conveyance of the paper P based on the leading edge detection signal from the paper sensor 32. Then, the paper P on which the image is formed is guided by the downstream guide portion 9 b and discharged to the paper discharge portion 31.

  Thereafter, the control of the control device 100 stops the driving of the paper feeding unit 101c, the guide units 9a and 9b, and the supply pump 57. The driving of the suction pump 58 is stopped at the timing when the rear end of the paper P faces the cylindrical member 61. Thus, the image recording operation of the printer 101 is completed.

  Next, a series of flows of the capping operation and the second humidification operation of the printer 101 will be described. When the printer 101 pauses the image recording operation or turns off the printer 101, the printer 101 performs a second humidification operation in addition to the capping operation.

  When the capping operation is performed, the maintenance control unit 154 controls the lift motor 49 to set the contact position where the lip member 42 contacts the support unit 52 as shown in FIG. Thereby, the cap member 41 partitions the discharge space S1 from the surrounding space S2.

  Thereafter, the maintenance control unit 154 drives the supply pump 57 for a predetermined time. Thereby, humid air is supplied from the through-hole 63b to the partitioned discharge space S1. For this reason, the humidity in the ejection space S1 increases, and it becomes possible to suppress drying of the ink near the ejection port 108.

  The printer 101 first performs an uncapping operation when the image recording operation is paused, that is, when a recording command is received in the partitioned state. That is, the maintenance control unit 154 controls the elevating motor 49 so that the lip member 42 is at the separation position as shown in FIG. Accordingly, the cap member 41 opens the discharge space S1 to the surrounding space S2. Thereafter, as described above, the image recording operation is executed.

  As described above, according to the present embodiment, the cylindrical member 61 of the facing member 51 is formed with the through-hole (opening) 63 b facing the discharge port 108. From the through hole 63b, humidified air is supplied when an image recording operation is executed. That is, humidified air is supplied from the through hole 63b toward the discharge port 108 when the discharge space S1 is in an open state and the paper P and the discharge port 108 do not face each other. The ejection port 108 is humidified even during a period when ink is not ejected onto the paper P. For this reason, drying of the ink in the vicinity of the ejection port is suppressed. As a result, ink discharge due to flushing or the like performed to suppress drying can be suppressed.

  The cylindrical member 61 supports the paper P that has been transported to a position facing the ejection surface 10 a with the upper surface 52 a of the support portion 52. This eliminates the need to provide a support member that supports the paper P separately from the facing member 51.

  Since the opposing member 51 has the support portion 52, even if moisture adhering to the supply of humidified air hangs down from the cylindrical member 61 to the side opposite to the head 10, it can be received by the support portion 52. Become. For this reason, moisture does not leak into the apparatus.

  Further, the upper end of the cylindrical member 61 and the upper surface 52a of the support portion 52 are disposed at the same height level. For this reason, the paper P can be supported by the cylindrical member 61 and the upper surface 52a. For this reason, the gap between the paper P and the ejection port 108 (ejection surface 10a) is more stable.

  As a first modification, the suction pump 58 and the pipe 56 are not provided, and the suction operation may not be performed in the image recording operation. Even in this case, when the paper P and the ejection port 108 are opposed to each other, the humid air is supplied to the back surface of the paper P, so that curling of the paper P can be suppressed.

  As a second modification, a pump capable of forward and reverse rotation may be employed as the supply pump 57 to supply humidified air and suck air from the through hole 63b. In this case, since the supply pump 57, the pipe 55, and the like serve as a common mechanism for the supply means for supplying the humidified air and the suction means for sucking the air, it is necessary to provide the suction pump 58, the pipe 56, and the like. Disappear. As a result, the configuration of the humidifying mechanism is simplified.

  In the second modification, as shown by a two-dot chain line in FIG. 5, the tank 59 is provided with an atmosphere opening portion 59 a that communicates with the upper space. A check valve (not shown) is attached to the atmosphere opening portion 59a, and air does not flow from the outside to the upper space. In this configuration, when the supply pump 57 is driven to rotate in the forward direction under the control of the control device 100, air flows in the direction of the white arrow in FIG. That is, humidified air is supplied from the through hole 63b. At this time, the outside air does not flow into the upper space by the check valve of the atmosphere opening portion 59a. For this reason, air flows into the tank 59 from the pipe 54, humid air is generated in the tank 59, and the humid air is supplied to the discharge space S1. On the other hand, when the supply pump 57 is driven to rotate in the reverse direction, air flows in the direction of the white arrow indicated by the broken line in FIG. That is, air is sucked from the through hole 63b, and the sucked air is discharged to the outside through the pipe 55, the upper space of the tank 59, and the atmosphere opening portion 59a.

  In this modification, when the paper P faces the ejection port 108, the humidified air is not supplied, so the supply amount of the humidified air per unit time is not adjusted. In addition, the other operations (capping and uncapping operation, second humidifying operation) are controlled in the same manner as in the above-described embodiment, and thus description thereof is omitted.

A series of flow of the image recording operation of the printer in this modification will be described.
When the printer receives the recording command, the image data is stored in the image data storage unit 152. At this time, the maintenance control unit 154 rotates the supply pump 57 in the forward direction to supply humidified air from the through hole 63b to the discharge space S1 (first humidifying operation). The humidified air is directed to the discharge surface 10a as in the above-described embodiment. In the present modification, the supply of humidified air and the suction of air are performed through the same through hole 63b, so that there is no need for the outer cylinder 63 and air can be distributed on the outer peripheral side surface of the inner cylinder 62. If the opening is formed, the protrusion 64a may not be particularly required.

  At this time, the conveyance control unit 151 controls the sheet feeding unit 101c, the guide units 9a and 9b, and the supply pump 57. The paper feeding unit 101c and the guide units 9a and 9b are driven almost simultaneously with the driving of the supply pump 57 by the maintenance control unit 154. As a result, the paper P is transported from the paper feed tray 20 between the ejection surface 10a and the facing member 51.

  The head controller 153 forms an image in synchronization with the conveyance of the paper P based on the leading edge detection signal from the paper sensor 32. As a result, ink is ejected from the ejection port 108 of the head 10, and a desired image is formed on the paper P. Then, the paper P on which the image is formed is guided by the downstream guide portion 9 b and discharged to the paper discharge portion 31.

  Based on the leading edge detection signal of the paper P, the maintenance control unit 154 supplies at the timing when the leading edge of the paper P faces the ejection surface 10a (more specifically, the timing immediately before the leading edge of the paper P reaches the recess 52b). The pump 57 is stopped. Based on the trailing edge detection signal of the paper P, the maintenance control unit 154 determines the timing at which the trailing edge of the paper P passes through the region facing the ejection surface 10a (more specifically, the trailing edge of the paper P is a concave portion). The driving of the forward rotation of the supply pump 57 is resumed at the timing immediately before crossing 52b. On the other hand, the driving of the supply pump 57 by the transport control unit 151 is also controlled based on the detection signal by the paper sensor 32. That is, the conveyance control unit 151 drives the supply pump 57 to rotate in the reverse direction at the timing when the leading edge of the paper P faces the cylindrical member 61 based on the leading edge detection signal of the paper P. Then, based on the trailing edge detection signal of the sheet P, the conveyance control unit 151 stops driving the supply pump 57 at a timing when the trailing edge of the sheet P faces the cylindrical member 61. Thereby, when the paper P is not opposed to the ejection surface 10a, humidified air is supplied from the through hole 63b, and when the paper P is opposed to the cylindrical member 61 (when opposed to the ejection port 108). In addition, external air is sucked through the through hole 63b (suction operation).

  When the suction operation is executed, the gap (gap) between the paper P and the ejection surface 10a becomes constant, so that the ink landing accuracy is improved and the image quality can be maintained. Further, while the image recording operation is being performed (in an open state), when the paper P and the discharge surface 10a (discharge port 108) are not opposed to each other, humidified air is supplied and the discharge port 108 is humidified. Is done. Since drying of the ink in the vicinity of the ejection port is suppressed, ink discharge due to flushing or the like can be suppressed.

  Thereafter, the control of the control device 100 stops the driving of the paper feeding unit 101c, the guide units 9a and 9b, and the supply pump 57. Thus, the image recording operation of the printer 101 is completed.

  As described above, in the printer of the second modified example, in the open state, it is possible to suppress drying of the ink in the vicinity of the ejection port in the open state. Moreover, the same effect can be acquired about the structure similar to the above-mentioned embodiment.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. For example, the opposing member may not have the cylindrical member 61. That is, an opening may be formed in a region facing the discharge port 108 of the support portion 52, and humidified air may be supplied from the opening to the discharge space S1. Further, the opening for supplying the humidified air to the discharge space S1 may not face the discharge port 108 as long as it is formed in the facing member. Moreover, the opposing member may be comprised only from the cylindrical member. In addition, when the paper P has a stub that the tip of the paper P conveyed by the feed roller pair 24 is held horizontally between the feed roller pairs 24 and 25, the opposing member 51 P may not be supported. Further, when the paper P is supported by the cylindrical member 61, the paper P may not be supported by the upper surface (front surface) 52 a of the support portion 52. Further, a driving mechanism for rotating the cylindrical member 61 may be provided, and the cylindrical member 61 may be positively rotated when the humidifying operation and the suction operation are performed. In this case, the rotation direction of the cylindrical member 61 is preferably rotated in the conveyance direction of the paper P.

  In addition, as a cap mechanism that can take the discharge space S1 in a partitioned state and an open state, a cap having a bottom portion facing the discharge surface 10a and an annular portion standing on the periphery of the bottom portion, and a tip end of the annular portion being the discharge surface It may be configured to include a moving mechanism that moves the cap to a position in contact with 10a and a position separated from the discharge surface 10a. In this case, humidified air may be supplied only when the cap is in the open state.

  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 machine, a copier, and the like. Further, recording is performed by discharging a liquid other than ink. The present invention can also be applied to a liquid ejection apparatus that performs the above. The recording medium is not limited to the paper P, and may be various recording media. Furthermore, the present invention can be applied regardless of the ink ejection method. For example, although a piezoelectric element is used in this embodiment, a resistance heating method or a capacitance method may be used.

DESCRIPTION OF SYMBOLS 8 Conveyance mechanism 10 Head 10a Discharge surface 40 Cap mechanism 50 Humidification mechanism 51 Opposing member 52 Support part 52a Upper surface (plane)
52b Recess 61 Cylindrical member 63a, 63b Through hole (opening)
100 Control device (control means)
101 Inkjet printer (liquid ejection device)
108 Discharge port S1 Discharge space S2 Surrounding space

Claims (10)

A head having a discharge port for discharging liquid;
A transport mechanism for transporting the recording medium to a position facing the ejection port;
A cap mechanism capable of taking a partition state in which the discharge space facing the discharge port is partitioned from the surrounding space of the discharge space, and an open state in which the discharge space is open to the surrounding space;
A humidifying mechanism having a facing member facing the discharge port and performing a humidifying operation for supplying humidified air to the discharge port from an opening formed on a surface of the facing member;
And a control means for controlling the humidifying mechanism so as to perform the humidifying operation when the cap mechanism is in the open state and the recording medium is not opposed to the ejection port. Discharge device.   The liquid ejecting apparatus according to claim 1, wherein the facing member supports, on the surface, a recording medium conveyed to a position facing the ejection port. The humidification mechanism includes a supply unit that performs the humidification operation, and a suction unit that performs a suction operation of sucking air in the discharge space from the opening,
The control unit controls the supply unit to perform the humidifying operation when the recording medium is not opposed to the ejection port, and the suction operation is performed when the recording medium is opposed to the ejection port. The liquid ejecting apparatus according to claim 2, wherein the suction unit is controlled to perform the operation. A plurality of the openings are formed on the surface of the facing member,
The supply means supplies humid air from a part of the openings of the plurality of openings,
The suction means sucks air from the openings other than the part,
4. The control unit according to claim 3, wherein the control unit controls the supply unit and the suction unit to perform the humidification operation and the suction operation when a recording medium faces the ejection port. 5. Liquid discharge device. The supply means and the suction means are composed of a common mechanism,
The control means performs only the suction operation when the recording medium faces the ejection port so that only the humidification operation is performed when the recording medium does not face the ejection port. The liquid ejecting apparatus according to claim 3, wherein the supply unit and the suction unit are controlled as described above.   2. The liquid ejection apparatus according to claim 1, wherein the control unit controls the humidification mechanism to perform the humidification operation even when a recording medium faces the ejection port. 3.   The control means is configured to increase the supply amount of humidified air supplied to the recording medium as the amount of liquid ejected to the recording medium based on the received recording command increases from a predetermined amount. The liquid ejecting apparatus according to claim 4, wherein the humidifying mechanism is controlled. The opposing member includes a cylindrical member whose axis extends in a direction orthogonal to the conveyance direction of the recording medium and is rotatably supported.
The liquid ejection device according to claim 1, wherein the opening is formed on a side surface of the cylindrical member.   The liquid ejecting apparatus according to claim 8, wherein the facing member further includes a receiving portion disposed at a position sandwiching the cylindrical member between the facing member and the ejection port. A concave portion in which the cylindrical member is disposed is formed on a plane facing the discharge port of the receiving portion,
The liquid discharge apparatus according to claim 9, wherein a portion of the cylindrical member that is closest to the discharge port is disposed at the same height level as the flat surface of the receiving portion.

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