JP2017087480A - Liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce negative pressure by sucking an empty discharge receiver with simple, inexpensive constitution through a short suction path without causing any fixation of ink.SOLUTION: An empty discharge receiver 5 is provided nearby an outer periphery of a conveyor drum 1. The empty discharge receiver 5 is provided extending along the axis of the conveyor drum 1, and a one-side end thereof (an end on the side of a suction duct 6) is opened to be open to an end of the conveyor drum 1. An arcuate suction duct 6 is provided outside a one-side end face of the conveyor drum 1. The suction duct 6 and the axial end opening of the empty discharge receiver 5 face each other across a very small gap. Then a suction fan 7 is driven to produce negative pressure in the suction duct 6, and ink discharged to the empty discharge receiver 5 is sucked into and collected in the suction duct 6.SELECTED DRAWING: Figure 2

Description

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

  2. Description of the Related Art Image forming apparatuses such as ink jet recording apparatuses are known as liquid ejecting apparatuses for ejecting liquid droplets from recording heads (hereinafter sometimes simply referred to as heads or recording heads) to form recordings. Yes. The “liquid ejecting apparatus” means an apparatus that ejects liquid droplets / liquid from an ejection head, and is not limited to an apparatus that performs image formation / image recording.

  In the image forming apparatus of the above-described droplet discharge recording method, since ink droplets are discharged from fine discharge ports, the nozzles are clogged due to thickening or sticking of ink due to drying or bubbles generated in the ink. May occur, resulting in ejection failure. Therefore, it is known to perform idle ejection in order to prevent such ejection failure.

  In addition, there is a droplet discharge recording type image forming apparatus that uses a transport drum as a transport unit that transports paper (including an OHP sheet or the like, also called a recording medium, a recording paper, or a recording material). For example, Japanese Unexamined Patent Application Publication No. 2010-5997 (Patent Document 1) discloses a single-wafer type impression cylinder conveyance type inkjet recording apparatus.

  Patent Document 1 discloses that purging is performed in order to prevent ink scattering around an impression cylinder where a single-wafer impression cylinder conveyance type inkjet head is arranged and to ensure ejection stability of the inkjet head. It is. In order to realize this, an opening having a shape corresponding to the ink ejection width of the head is provided at the non-holding position where the recording medium is not held on the peripheral surface of the transfer cylinder provided at the position facing the inkjet head, A path communicating with the opening is provided integrally with the opening inside the impression cylinder. The ink purged through the suction flow path (empty ejection) and the ink mist generated by image recording are collected from the opening into the pressure cylinder.

  In a conventional image forming apparatus that forms an image by ejecting ink by an ink jet head onto a sheet conveyed by a rotating drum, an empty discharge receiver that receives the ink discharged in an area other than the image forming area on the outer periphery of the drum is provided. Yes. Then, mist or the like is sucked out of the idle discharge receptacle and sucked so as not to contaminate the inside of the machine or the paper to form a negative pressure, thereby performing idle discharge.

  However, in order to suck the empty discharge receiver of the rotating drum, it is necessary to provide a suction fan inside the rotating drum, or to provide a suction fan outside by configuring a suction path from the empty discharge receiver to the outside of the drum. When a fan is provided inside the drum, problems of electrical connection and processing of ink accumulated by suction become a problem. In addition, when the suction path is configured to the outside, the drum shaft is hollow and fixed, the drum is rotated and supported by a large bearing, and suction is performed from the hollow portion of the fixed rotating shaft. In addition, since the suction path is long, the ink is fixed in the middle of the path, and in the worst case, the suction cannot be performed. In particular, recently, highly dry ink has been used to speed up the fixing of the ink in order to increase the printing speed, and there is a tendency that a problem of sticking tends to occur.

  In the above-mentioned Patent Document 1, an opening 504 is provided at a non-holding position where a recording medium is not held, and ink discharged in an idle manner by suction through a suction channel (506) communicating with the opening is provided. The mist is collected, and the problem that the rotation support portion of the drum is large and expensive, or the suction path becomes long and the ink is fixed and cannot be sucked, cannot be solved.

  The present invention has been made in view of the above-described problems in the conventional liquid ejection device, and has a simple and inexpensive configuration, a short suction path, and no ink sticking. It is an object of the present invention to provide a liquid ejection device capable of forming the liquid.

  In order to solve the above problems, the present invention conveys a recording material along the outer periphery of a rotating drum, and discharges the liquid from an ejection head disposed in a circumferential direction so as to face the drum circumferential surface. In the liquid discharge apparatus for forming a recorded matter on a recording material, the liquid discharge apparatus includes at least one empty discharge receiver disposed near the outer periphery of the drum and extending in the drum axial direction, and receiving liquid from the discharge head. The discharge receiver has an opening that is opened on at least one end surface of the drum, and negative pressure forming means that is disposed opposite to the opening via a gap is fixedly provided separately from the drum. It is characterized by that.

  According to the liquid ejection apparatus of the present invention, it is possible to eliminate problems such as ink sticking that occurs in a configuration having a long suction path as in the conventional configuration, and further, a configuration in which the drum rotation shaft is a fixed hollow shaft and is rotatably supported by a large bearing Without any restriction, it is possible to form a negative pressure by sucking the empty discharge receptacle with a simple configuration at low cost.

1 is a diagram illustrating a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention. It is a front view which shows a conveyance drum part in detail. It is a top view of the conveyance drum in the position which the empty discharge receptacle has rotated to the upper part. It is A sectional view taken on the line of FIG. It is a 3rd page figure which shows the structure of 2nd Example. It is a 3rd page figure showing the composition of the 3rd example. It is a front view which shows the arrangement | positioning angle of the circumferential direction of a suction duct. It is a front view which shows the ink absorber arrange | positioned at the bottom part of the idle discharge receptacle.

  FIG. 1 is a diagram showing a schematic configuration of an ink jet recording apparatus which is an example of a liquid ejection apparatus according to the present invention. The ink jet recording apparatus shown in this figure is of a type that transports a recording medium using a transport drum, and includes a transport drum 1, a paper feed unit 2, an ink jet head (discharge head) 4, and the like.

  At least one paper gripper 3 is provided on the outer periphery of the transport drum 1, grips the leading edge of the paper P sent from the paper feed unit 2 from the left side of the transport drum 1, and rotates the transport drum 1 counterclockwise in the figure. Then, the sheet is wound around the conveying drum 1 to convey the sheet, and an image is discharged onto the sheet P conveyed by the drum by ejecting ink from a plurality of circumferentially (radially) ink jet heads (ejection heads) arranged on the upper part of the conveying drum. The paper gripper 3 is opened to the paper discharge unit on the right side of the transport drum, and the paper on which the image is formed is discharged.

  FIG. 2 is a front view showing the conveyance drum unit in detail. FIG. 3 is a top view of the transport drum at a position where the idle discharge receiver has been rotated upward. 4 is a cross-sectional view taken along the line A in FIG.

  An empty discharge receiver 5 is provided at an end face of at least one drum in an area where the sheet of the conveyance drum 1 is not conveyed. At least one idle discharge receiver 5 is provided. As shown in FIGS. 3 and 4, the idle discharge receiver 5 is provided so as to extend in the axial direction of the transport drum 1, and one end portion thereof (an end portion on the negative pressure forming means 8 side described later) is provided. It is open (opens at the end face of the transport drum 1). The idle discharge receptacle 5 may be open at both ends (also on the side opposite to the negative pressure forming means 8).

  Further, an arcuate suction duct 6 is provided outside the end surface on one side of the transport drum 1 in an angular region where the inkjet head 4 is disposed when viewed from the axial direction as shown in FIG. As shown in FIG. 4, the suction duct 6 and the axial end opening 5b of the idle discharge receptacle 5 are provided so as to face each other through a minute gap. The minute gap is preferably greater than 0 mm and 1 mm or less. A suction fan 7 is attached to the suction duct 6. By driving the suction fan 7, a negative pressure can be formed in the suction duct 6. The suction duct 6 and the suction fan 7 constitute negative pressure forming means 8. The negative pressure forming means 8 (suction duct 6 and suction fan 7) is provided separately from the transport drum 1 and fixed to the apparatus main body. Note that the suction duct 6 has a surface facing the transport drum 1 and a portion corresponding to the suction fan 7 open, and the other portions are closed.

  When the transport drum 1 is rotated 90 degrees counterclockwise from the state of FIG. 2, the idle discharge receiver 5 is rotated to the upper part of the drum as shown in FIGS. As a result, the opening 5a of the idle ejection receiver 5 (the opening that receives the idlely ejected ink) faces the inkjet head 4 (FIG. 3). In FIG. 3, the ink jet head 4, paper, and the like are omitted. Further, the end opening 5b of the idle discharge receiver 5 is opposed to the suction duct 6 (FIG. 4).

  In such a configuration, idle ejection is performed in a state where the opening 5 a of the idle ejection receiver 5 is opposed to each inkjet head 4. When performing the idle discharge, the suction fan 7 is driven to operate the negative pressure forming means 8. As a result, when the idle discharge from the inkjet head 4 is discharged to the idle discharge receiver 5, a negative pressure is formed by the negative pressure forming means 8 provided in the end opening 5 b of the idle discharge receiver 5 through a minute gap. As a result, the ink discharged to the idle discharge receiver 5 can be sucked into the suction duct 6 and collected.

  In this configuration, the suction path for sucking the ink that has been ejected idle is only a minute gap between the end opening 5b of the idle ejection receptacle 5 and the suction duct 6 (negative pressure forming means 8). Further, it is not necessary that the drum rotation shaft be a hollow shaft. Therefore, it is possible to eliminate problems such as ink sticking caused by a configuration having a long suction path as in the conventional configuration, and further, there is no restriction on the configuration in which the drum rotation shaft is supported by a large-sized bearing as a fixed hollow shaft, and the configuration is simple. The object can be achieved at low cost with the configuration.

  FIG. 5 is a view showing an embodiment (second embodiment) in which a circumferential rib is provided on the drum end face to enhance the negative pressure forming effect in the negative pressure forming means 8. 5 (a) is a front view, FIG. 5 (b) is a top view at a position where the idle discharge receiver has been rotated upward, and FIG. 5 (c) is a cross-sectional view taken along line A in FIG. 5 (b).

  As described above, the suction duct 6 of the negative pressure forming means is provided at a minute distance from the end surface of the transport drum 1 (the end opening 5b of the idle discharge receiver 5). As can be seen from FIGS. 2 and 5A, the suction duct 6 has an arcuate side shape when viewed from the drum axial direction. Circumferential ribs 9 and 10 are provided on both the outer peripheral side and the inner peripheral side of the arc side so as to be close to the arc side of the suction duct 6. As shown in FIG. 5C, the outer peripheral side rib 9 and the inner peripheral side rib 10 are both projected from the end surface of the transport drum 1, and the outer peripheral side arc side and the inner peripheral side arc side of the suction duct 6. Further, they are provided so as to face each other through a minute gap.

  In this embodiment, by providing a circumferential rib on the arc side of the suction duct 6 via a minute gap, a minute gap other than the end opening 5b of the idle discharge receiver 5 in the negative pressure forming means 8 is provided. The path (suction path) becomes longer, suction from other than the idle discharge receiver 5 is suppressed, and the suction efficiency of the idle discharge receiver is improved. Thereby, the ink ejected to the idle ejection receptacle 5 can be efficiently sucked and collected. The minute gap between the suction duct 6 and the end face of the transport drum 1 and the minute gap between the suction duct 6 and the ribs 9 and 10 are preferably larger than 0 mm and smaller than 1 mm.

  FIG. 6 is a view showing an embodiment (third embodiment) in which a fitting groove for fitting with the circumferential ribs 9 and 10 in the embodiment of FIG. 5 is provided. 6 (a) is a front view, FIG. 6 (b) is a top view at a position where the idle discharge receiver has been rotated upward, and FIG. 6 (c) is a cross-sectional view taken along line A in FIG. 6 (b).

  As shown in FIG. 6, an “L” -shaped member is formed on the outer peripheral side of the arc side of the suction duct 6. Further, an “L” -shaped member that forms a fitting groove 12 that fits with the inner peripheral rib 10 is protruded on the inner peripheral side of the arc side of the suction duct 6. The circumferential ribs 9 and 10 are the same as in the embodiment of FIG. The circumferential ribs 9 and 10 and the fitting grooves 11 and 12 (members) are fitted (fitted together) through a minute gap, thereby the ribs 9 and 10 and the fitting groove 11. , 12 (members forming) is formed with a labyrinth seal (non-contact sealing seal). Thereby, the suction from other than the idle discharge receiver 5 is further suppressed, and the suction efficiency of the idle discharge receiver is further improved. Thereby, the ink ejected to the idle ejection receptacle 5 can be sucked and collected more efficiently. A minute gap between the suction duct 6 and the end surface of the transport drum 1, a minute gap between the suction duct 6 and the ribs 9 and 10, and the ribs 9 and 10 and the fitting grooves 11 and 12 (are formed. The minute gap between the member and the member is preferably greater than 0 mm and 1 mm or less.

  Incidentally, as shown in FIG. 7, the suction duct 6 is provided such that the circumferential arrangement angle α is equal to or larger than the circumferential arrangement angle β of the plurality of inkjet heads 4 arranged. As a result, the suction duct 6 is disposed to the front of the ink jet head 4 in the paper transport direction (counterclockwise direction in FIG. 7). For this reason, when the idle discharge receiver 5 is rotated in the counterclockwise direction in FIG. 7, the idle discharge receiver 5 is moved by the negative pressure forming means 8 from a position before the discharge direction from the inkjet head 4 in the transport direction. Sucked. That is, since the air flow sucked from the inside of the empty discharge receiver 5 is generated before the empty discharge, the ink discharged in the air is efficiently sucked and collected on the air flow. Here, the first embodiment of FIG. 2 has been described, but the same applies to the second and third embodiments.

  Also, as shown in FIG. 8, it is preferable to arrange an absorber 13 that absorbs ink at the bottom of the idle discharge receiver 5 (in the central direction of the transport drum 1). In this example, it is assumed that the absorber 13 is replaceable. Ink that cannot be sucked by the negative pressure forming means 8, such as large droplets of ink ejected from the ink jet head 4 can be absorbed and held by the absorber 13, so that the ink is discharged from the gap between the transport drum 1 and the suction duct 6 when waiting for the machine. It is possible to prevent the ink from dripping or being sucked well during the operation of the machine and causing ink to spill from the gap and soiling the paper and equipment. Here, the first embodiment of FIG. 2 has been described, but the same applies to the second and third embodiments.

  As described so far, in the present invention, there is provided at least one empty discharge receiver that is disposed near the outer periphery of the transport drum and extends in the drum axial direction, and receives liquid from the discharge head. Has an opening that is opened on at least one end face of the drum, and negative pressure forming means that is disposed opposite to the opening via a gap is fixedly provided separately from the drum. Therefore, it is possible to eliminate problems such as ink sticking caused by a configuration having a long suction path as in the conventional configuration, and further, there is no restriction on the configuration in which the drum rotation shaft is supported by a large-sized bearing as a fixed hollow shaft, and simple. The negative pressure can be formed by sucking the empty discharge receptacle at a low cost with the configuration.

  In addition, a rib is provided on the end surface of the drum, and the suction path other than the opening of the idle discharge receiver in the negative pressure forming means is extended, so that the suction efficiency is improved and negative pressure can be increased. Ink can be reliably collected.

  In addition, a fitting groove that fits into the rib provided on the end surface of the drum is provided in the duct member that constitutes the negative pressure forming means, and a non-contact sealing structure further suppresses suction from other than the idle discharge receptacle. Thus, the suction efficiency of the empty discharge receiver is further improved. As a result, the ink discharged to the idle discharge receiver can be sucked and collected more efficiently.

  Further, a plurality of discharge heads are arranged in the circumferential direction of the transport drum, and the arrangement angle in the drum circumferential direction of the duct member constituting the negative pressure forming means is set to be greater than the arrangement angle of the plurality of discharge heads. An air flow is generated by suction in the empty discharge receptacle before empty discharge, and ink can be collected efficiently by empty discharge in that state, and mist etc. flying in the empty discharge receiver after empty discharge It can be reliably recovered.

  In addition, by arranging a replaceable liquid absorber at the bottom of the empty discharge receiver, ink such as large droplets that have not been sucked by the negative pressure forming means can be held by the absorber, contaminating equipment and paper. Can solve the problem.

  As mentioned above, although this invention was demonstrated by the example of illustration, this invention is not limited to this. The “liquid” is not limited to recording liquid and ink, and is not particularly limited as long as it becomes a fluid when ejected. The “liquid ejecting apparatus” means an apparatus that ejects liquid from a liquid ejecting head, and is not limited to an apparatus that performs image formation / image recording like an image forming apparatus. Further, the configuration of the ejection head is arbitrary. Any method can be adopted as the discharge method. Further, the liquid discharge direction can be set in an appropriate direction. In the image forming apparatus, the number of ink colors is not limited to four, and can be configured with any number of colors. As the configuration of each part of the image forming apparatus, an appropriate configuration can be adopted as long as the present invention can be implemented, and the present invention can be applied to both a serial type image forming apparatus and a line type image forming apparatus.

DESCRIPTION OF SYMBOLS 1 Conveyance drum 2 Paper feed unit 3 Paper gripper 4 Inkjet head (discharge head)
5 Empty discharge receiver 5a Opening (opening for receiving empty discharged ink)
5b Axial end opening 6 Suction duct 7 Suction fan 8 Negative pressure forming means 9 Outer peripheral side rib 10 Inner peripheral side rib 11 Outer peripheral side fitting groove 12 Inner peripheral side fitting groove 13 Absorber

JP 2010-5997 A

Claims (6)

In a liquid ejecting apparatus that forms a recorded matter on the recording material by conveying the recording material along the outer periphery of the rotating drum and ejecting liquid from an ejection head disposed in a circumferential direction facing the drum circumferential surface ,
The drum is disposed near the outer periphery of the drum and extends in the drum axial direction, and has at least one empty discharge receiver for receiving liquid from the discharge head;
The idle discharge receiver has an opening opened on at least one end surface of the drum, and negative pressure forming means disposed opposite to the opening via a gap is provided separately from the drum. A liquid discharge apparatus characterized by that.   The liquid ejection apparatus according to claim 1, wherein a rib is provided on an end surface of the drum, and a suction path of the negative pressure forming unit is extended from a portion other than the opening of the idle ejection receptacle.   The liquid ejection device according to claim 2, wherein a fitting groove that fits into the rib is provided in a duct member that constitutes the negative pressure forming unit to form a non-contact sealing structure. A plurality of the discharge heads are arranged in the circumferential direction of the drum,
4. The arrangement according to claim 1, wherein an arrangement angle of the duct member constituting the negative pressure forming unit in the circumferential direction of the drum is set to be greater than an arrangement angle of the plurality of ejection heads. The liquid discharge apparatus according to 1.   The liquid discharge apparatus according to claim 1, wherein a replaceable liquid absorber is disposed at a bottom portion of the empty discharge receiver. The liquid discharging apparatus according to claim 1, wherein the negative pressure forming unit is fixed to the apparatus main body.

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