JP2019162867A - Liquid discharge unit and liquid discharge device - Google Patents

Abstract

To provide a liquid discharge unit and a liquid discharge device which control a relative position of a recorded medium and a head array, and can obtain high positioning accuracy even in recovery operation.SOLUTION: A liquid discharge unit includes: a head array 3 in which a plurality of liquid discharge heads 2 are arranged in a width direction orthogonal to a conveying direction of a recorded medium 6 on which an image is recorded; a support body 7; and contact/separation means 4 which contacts/separates the head array 3 to/from an adjacent position and a separation position with respect to a recording area of the recorded medium 6; head array fixing means 16 which fixes the head array 3 in the adjacent position. The head array fixing means 16 includes: a held member 8 arranged one of the head array 3 or the support body 7; and holding members 9A, 9B which are arranged on the other of the head array 3 or the support body 7, and hold the held member 8 and position in the conveying direction and the width direction of the held member 8. The holding members 9A, 9B can adjust a held position of the held member 8 in at least one direction out of the conveying direction and the width direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid discharge unit and a liquid discharge apparatus.

  In an image forming apparatus such as a printer or a facsimile that employs an ink jet system, landing accuracy of ink droplets on a recording medium is important in order to improve the quality of an output image. For this reason, there is known a technique for suppressing a relative position variation between a recording medium on which ink droplets land and a head array having a plurality of liquid ejection heads each having a nozzle for ejecting ink droplets.

  As an example of such a technique, a head array that is two-dimensionally arranged is urged by an urging unit in the nozzle arrangement direction, and the spring constant of the urging unit is set according to the conveyance speed of the recording medium and the adjacent nozzle. A technique is known in which a spatial frequency that depends on the conveyance direction pitch and the relative vibration period between the nozzle and the recording medium is avoided (see, for example, “Patent Document 1”).

However, in the above-described technique, there is no means for fixing the head array in the direction perpendicular to the nozzle arrangement direction and the up-and-down direction at the time of the head array up-and-down operation accompanying the recovery operation of the head array. The positioning repeatability of the relative position between the medium and the head array is poor, and there is a problem that a certain amount of positional deviation occurs after the lifting and lowering operation.
The present invention solves the above-described problems, and provides a liquid ejection unit and a liquid ejection apparatus capable of controlling the relative position between a recording medium and a head array and obtaining high repeated positioning accuracy even during a recovery operation. With the goal.

  According to a first aspect of the present invention, there is provided a head array in which a plurality of liquid ejection heads for ejecting liquid are arranged in a width direction orthogonal to a conveyance direction of a recording medium on which an image is recorded, a support, and the recording target Contact and separation means for contacting and separating the head array at a proximity position close to and away from a recording area of the medium; and a head array fixing means for fixing the head array at the proximity position; The array fixing means is provided on one of the head array or the support and is provided on a gripped member extending in the contact / separation direction of the head array and on the other of the head array or the support. A gripping member that grips the gripped member and positions the gripped member in the transport direction and the width direction, and the gripping member has a small amount in the transport direction and the width direction. Characterized in that said at Kutomo one direction can adjust the gripping position of the gripping member.

  According to the present invention, when the head array occupies the close position again after being separated from the recording area in the recovery operation or the like, the position of each liquid ejection head is positioned by the head array fixing means, so that high recording accuracy is maintained. can do.

It is a schematic block diagram at the time of head array separation of the liquid discharge unit which employ | adopted one Embodiment of this invention. FIG. 2 is a schematic configuration diagram of a liquid ejection unit that employs an embodiment of the present invention when close to a head array. It is a schematic perspective view of the holding member used for one embodiment of the present invention. It is the schematic explaining the holding member used for one Embodiment of this invention. It is a schematic perspective view explaining the holding member used for one Embodiment of this invention. It is a schematic block diagram at the time of head array separation of the liquid discharge unit in the modification of one embodiment of the present invention. It is a schematic block diagram at the time of head array proximity | contact of the liquid discharge unit in the modification of one Embodiment of this invention. It is a schematic front view of the liquid discharge apparatus which can mount the liquid discharge unit of this invention.

  FIG. 1 shows a liquid discharge unit 1 that employs an embodiment of the present invention. In the figure, the liquid discharge unit 1 has a plurality of recording heads 2 which are liquid discharge heads. The plurality of recording heads 2 are arranged in the head array body 3a so as to be staggered from each other for manufacturing reasons such as yield and processing limit, and the head array 3 is formed so that an arbitrary recording area is formed. Is configured.

  The recording head 2 needs to be close to the recording area through which the recording medium passes so that the ejected droplets land with high accuracy, while maintaining and recovering capping and wiping to maintain and recover the liquid ejection capability. In order to perform the operation, it is necessary to move away from the recording area. The liquid ejection unit 1 performs the above-described approaching / separating operation by moving the head array 3 in the vertical direction in FIG. The liquid ejection unit 1 occupies the state shown in FIG. 1 when separated from the recording area, and the state shown in FIG. 2 when close to the recording area.

The moving mechanism 4 serving as a contacting / separating means for moving the head array 3 in and out of the recording area is configured to allow reciprocating motion in one direction such as a ball screw. An approaching / separating operation is performed with respect to a recording area of a transfer sheet 6 which is a recording medium passing through a conveying unit 5 included in the apparatus. In FIGS. 1 and 2, the paper direction (the front side and the back side) is the conveyance direction of the transfer sheet 6, and the left-right direction is the width direction.
The moving mechanism 4 is fixed so as not to move relative to a support frame 7 as a support of the liquid discharge unit 1. A rigid body may be interposed between the support frame 7 and the moving mechanism 4.

  In the proximity shown in FIG. 2, the transfer sheet 6 is transported by the transport unit 5 and passes near the lower portion of the head array 3. At this time, vibration is generated with the transport operation of the transport unit 5. On the other hand, the head array 3 has a weight that cannot be ignored due to its configuration. For this reason, when the head array 3 is moved up and down during the recovery operation and the recording operation, the relative position between the head array 3 and the transfer sheet 6 is shifted, and the recording accuracy is deteriorated. The present invention prevents the occurrence of this problem.

  As shown in FIGS. 1 and 2, positioning pins 8 as members to be gripped are formed on both side surfaces of the head array main body 3a so as to extend in the contact / separation direction of the head array 3 which is the vertical direction in the drawing. It has been. The positioning pin 8 having a cylindrical shape is fixed to the head array body 3a by means such as welding, bonding, and screwing. 1 and 2, the configuration in which the positioning pins 8 are directly fixed to the head array body 3a is shown, but they may be fixed via a holding member such as a bracket.

  Grip members 9 </ b> A and 9 </ b> B that hold the positioning pins 8 are attached to the support frame 7. As shown in FIGS. 3 and 4, each gripping member 9 </ b> A, 9 </ b> B includes a fixing portion 9 a fixed to the support frame 7 and gripping portions 9 b, 9 c attached to each fixing portion 9 a in an adjustable manner. Yes. A block-shaped fixing portion 9a made of a rigid body having a certain thickness is common to the gripping members 9A and 9B, and is fixed to the support frame 7 directly or via a bracket. Two taps 9f (see FIG. 5) for attaching the grip portions 9b and 9c are formed on the upper surface of the fixed portion 9a.

The gripping member 9A has a gripping portion 9b shown in FIG. 4A, and the gripping member 9B has a gripping portion 9c shown in FIG. 4B. The holding part 9b has three bearings 10 which are rotating members inside, and each bearing 10 has support shafts 11a and 11b arranged so that the respective shaft centers are perpendicular to each other, and a support shaft 11a. The shaft 11c is rotatably supported by a support shaft 11c arranged so that the shaft center is parallel to the shaft center.
Each of the support shafts 11b and 11c is fixed to the grip portion 9b, and only the support shaft 11a is provided so as to be movable in the vertical direction in the figure. A biasing force of a biasing member (not shown) is applied to the support shaft 11a, and the support shaft 11a is always biased upward in the drawing.

A rectangular hole 9d is formed in the center of the gripping portion 9b so that the peripheral surface of each bearing 10 is exposed on one side thereof. The side of the hole 9d that is not exposed to each bearing 10 is the side of the positioning pin 8. It is formed in an arc shape so as to have a similar shape to the peripheral surface.
A contact piece 12 that comes into contact with the support shaft 11a is disposed inside the grip portion 9b. The contact piece 12 is configured to be movable in the vertical direction in the figure, and the tip of a positioning screw 13 screwed to the grip portion 9b is in contact with the upper surface thereof. With this configuration, the position of the support shaft 11a can be adjusted with respect to the conveying direction of the transfer sheet 6 by the positioning screw 13, so that the positioning pin 8 is gripped by at least the bearings 10 supported by the support shafts 11a and 11b. be able to.
In addition, the grip portion 9b is formed with a long hole 9e that can be positioned in the width direction of the transfer sheet 6 when being fixed to the fixing portion 9a. The holding part 9b is fixed to the fixing part 9a by two fixing screws 14.

As shown in FIG. 5, on the upper surface of the fixing portion 9a on which the tap 9f is formed, two positioning pins 9g that are formed to project upward are respectively planted at positions inside the respective taps 9f. Has been. Each positioning pin 9g is fixed to the fixing portion 9a by a method such as screwing or welding.
Each positioning pin 9g can be inserted into the bottom surface of the gripping portion 9b, and two elongated holes 9h are formed that can be positioned in the conveyance direction of the transfer sheet 6 when being fixed to the fixing portion 9a. Has been. Since each gripping portion 9b can be moved in the conveying direction of the transfer sheet 6 by each positioning pin 9g and each long hole 9h, each long hole 9e described above is provided in each tap 9f by the movable area. On the other hand, the fixing screw 14 is sufficiently large with respect to the elongated hole 9e.

Next, the grip 9c will be described, but the same components as those of the grip 9b are designated by the same reference numerals, and detailed description thereof is omitted. The grip portion 9c has three bearings 10 therein, and the bearings 10 are arranged so that the shafts are perpendicular to the shafts 11a and 11c and the shaft center of the shaft 11a. The support shaft 11d is rotatably supported. The support shaft 11d is provided so as to be movable in the left-right direction in the drawing, and the support shaft 11a is always urged to the right in the drawing by the urging force of the urging member 15 having one end in contact with the right side thereof. . The other ends of the urging member 15 are in contact with the tips of two positioning screws 18 screwed into the grip portion 9c. With this configuration, the position of the support shaft 11 d can be adjusted with respect to the width direction of the transfer sheet 6 by each positioning screw 18.
The above-described positioning pins 8 and the gripping members 9A and 9B constitute a head array fixing means 16.

With the above-described configuration, the holding portions 9b and 9c are temporarily fixed to the fixing portions 9a by the fixing screws 14, and then the head array 3 is lowered to hold the positioning pins 8 by the holding members 9A and 9B. At this time, adjustment by the long holes 9e and 9h and adjustment by the positioning screws 13 and 18 are performed so that the positioning pins 8 are gripped by the bearings 10.
By performing the recording operation after the adjustment, the head array 3 occupying the close position is gripped by the gripping members 9A and 9B, so that the position of each recording head 2 at the time of the recording operation. Is positioned by the head array fixing means 16, and high recording accuracy can be maintained. Further, when the head array 3 occupies the close position even after the head array 3 is separated from the recording area in the recovery operation or the like, since the position of each recording head 2 is positioned by the head array fixing means 16, high recording accuracy is similarly maintained. be able to.

  In the above-described embodiment, the cylindrical positioning pin 8 is used as the member to be gripped. However, as long as the member to be gripped can be gripped by the gripping members 9A and 9B, such as a prismatic or polygonal columnar positioning pin, any method can be used. Any shape may be used. Further, although the gripping members 9A and 9B having the bearings 10 which are three rotating members are shown as the gripping members, gripping members having a configuration having four or more bearings 10 may be used.

Next, a modified example of the above-described embodiment will be described. In this modification, as shown in FIGS. 6 and 7, as compared with the above-described embodiment, the gripping members 9A and 9B are attached to the head array body 3a side as the head array fixing means 16, and the positioning pins 8 are attached to the support frame 7. It differs only in the point attached to the side, and another structure is the same.
FIG. 6 shows the separated state and FIG. 7 shows the approached state, and each positioning pin 8 is fixed to the support frame 7 via the mounting bracket 19.
Even with this configuration, it is possible to obtain the same effects as those of the above-described embodiment. Further, since the positioning pin 8 and the gripping members 9A and 9B can be arranged on either the upper or lower side, the degree of freedom in design can be improved.

Next, an ink jet recording apparatus as a liquid discharge apparatus equipped with the above-described liquid discharge unit 1 will be described with reference to FIG.
An ink jet recording apparatus 54 as a liquid ejecting apparatus has a head array 3 that can move in the main scanning direction and mount each recording head 2 inside the apparatus main body. Further, inside the apparatus main body, a liquid discharge unit 1 and the like configured by each recording head 2 and an ink tank 17 for supplying ink to each recording head 2 are stored. A sheet feeding cassette (or a sheet feeding tray) 59 on which a large number of transfer sheets 6 as recording media can be stacked is detachably mounted on the lower part of the apparatus main body from the front side. Further, the apparatus main body is provided with a manual feed tray 60 that is opened when the transfer sheet 6 is manually fed. The ink jet recording apparatus 54 takes in the transfer sheet 6 fed from the paper feed cassette 59 or the manual feed tray 60, records a desired image by the liquid discharge unit 1, and then arranges the transfer sheet 6 after image formation on the rear surface side. The paper is discharged to the paper discharge tray 61 provided.

  The head array 3 is provided with recording heads 2 that discharge ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk). In addition, each ink tank 17 that supplies each color ink to each recording head 2 is replaceably mounted on the head array 3. Each ink tank 17 has an air port that communicates with the air at the top and a supply port that supplies ink to each recording head 2 at the bottom. A porous body filled with ink is provided inside the ink tank 17, and the ink supplied to the recording head 2 is maintained at a slight negative pressure by the capillary force of the porous body.

The head array 3 is supported by the above-described moving mechanism 4 so as to be movable up and down in FIG. The head array 3 selectively occupies the separation position shown in FIG. 1 and the proximity position shown in FIG. 2 by a driving force from a driving means (not shown) included in the moving mechanism 4.
On the other hand, in order to convey the transfer sheet 6 set in the paper feed cassette 59 to the lower side of the recording head 2, a paper feed roller 68 and a friction pad 69 for separating and feeding the transfer sheet 6 from the paper feed cassette 59 are provided. ing. Further, a guide member 70 for guiding the transfer sheet 6 and a conveyance roller 71 for inverting and conveying the fed transfer sheet 6 are disposed. Further, a conveyance roller 72 pressed against the circumferential surface of the conveyance roller 71 and a leading end roller 73 for defining a feeding angle of the transfer sheet 6 from the conveyance roller 71 are provided. The transport roller 71 is rotationally driven through a gear train by a sub scanning motor (not shown).
Thus, the conveying means 5 is configured.

  In order to guide the transfer sheet 6 fed from the conveyance roller 71 at a position below each recording head 2, a printing receiving member 74, which is a sheet guide member, is provided. A conveyance roller 75 and a spur 76 that are rotationally driven to send the transfer sheet 6 in the paper discharge direction are provided on the downstream side of the printing receiving member 74 in the sheet conveyance direction. Further, a discharge roller 77 and a spur 78 for sending the transfer sheet 6 to the discharge tray 61, and guide members 79 and 80 for forming a discharge path are provided.

  In the ink jet recording apparatus 54 described above, each recording head 2 is driven in accordance with an image signal during recording. Thus, ink is ejected onto the stopped transfer sheet 6 to record one line, and after that, the transfer sheet 58 is conveyed by a predetermined amount, and then the next line is recorded. Upon receiving a recording end signal or a signal that the rear end of the transfer sheet 6 reaches the recording area, the inkjet recording apparatus 54 ends the recording operation and discharges the transfer sheet 6.

  A recovery device (not shown) for recovering the ejection failure of each recording head 2 is disposed at a position outside the recording area. The recovery device has a suction cap, a pump, and a wiping device. Each recording head 2 is capped with a suction cap during printing standby to keep the nozzles in a wet state, thereby preventing ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the nozzles is made constant and a stable ejection state is maintained.

  When a discharge failure occurs, the nozzle of the recording head is sealed with a suction cap, and bubbles and the like are sucked out of the nozzle together with the ink through a waste ink passage. Then, ink or dust attached to the nozzle surface is removed by a wiping brush, thereby recovering the ejection failure. The sucked ink is discharged to a waste liquid tank provided at the lower part of the main body and absorbed and held by an ink absorber provided inside the waste liquid tank.

Since the above-described ink jet recording apparatus 54 is equipped with the liquid ejection unit 1 of the present invention, the position of each recording head 2 during the recording operation is positioned by the head array fixing means 16 and high recording accuracy can be maintained. it can. Further, when the head array 3 occupies the close position even after the head array 3 is separated from the recording area in the recovery operation or the like, since the position of each recording head 2 is positioned by the head array fixing means 16, high recording accuracy is similarly maintained. be able to.
In the above description, the liquid ejecting unit 1 ejects ink. However, the liquid to which the present invention can be applied is not limited to ink. For example, the liquid ejecting unit 1 may be used in an apparatus for ejecting a liquid resist for patterning. May be applied. Furthermore, the liquid discharge unit 1 may be applied to an apparatus for discharging a gene analysis sample.

  In the above-described embodiment and each modified example, an example using a color printer as a liquid ejecting apparatus has been described. . In this embodiment and the modification, the transfer sheet 6 is used as a recording medium on which an image is formed. However, the transfer sheet 6 is not limited to the recording paper, and is a thick paper, a postcard, an envelope, a normal It includes paper, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheet, OHP film, resin film, etc. It may be used.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to such specific embodiments, and unless specifically limited by the above description, the present invention described in the claims is not limited. Various modifications and changes are possible within the scope of the gist.
For example, in the embodiment and the modification described above, the mechanism for adjusting the position of the support shaft 11 a in the conveying direction of the transfer sheet 6 by the positioning screw 13 and the position of the support shaft 11 d in the width direction of the transfer sheet 6 by the positioning screws 18. Although the configuration including both the adjusting mechanisms is shown, a configuration having only one of the mechanisms may be used.
In the above-described embodiment, the configuration in which the support frame 7 provided with the gripping members 9A and 9B supports the head array 3 is shown. However, the frame provided with the gripping members 9A and 9B and the head array 3 are supported. The frame may be configured separately. Further, instead of the support frame 7 as a frame, a block-shaped or arm-shaped support may be used.
The effects described in the embodiments of the present invention are merely examples of the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

1 Liquid discharge unit 2 Liquid discharge head (recording head)
3 Head array 4 Contact / separation means (movement mechanism)
6 Recording medium (transfer sheet)
7 Support (support frame)
8 Grip member (positioning pin)
9A, 9B Grip member 10 Rotating member (bearing)
16 Head array fixing means 54 Liquid ejection device (inkjet recording device)

Japanese Patent No. 5436382

Claims (6)

A head array in which a plurality of liquid ejection heads for ejecting liquid are arranged in a width direction orthogonal to a conveyance direction of a recording medium on which an image is recorded;
A support;
Contact / separation means for contacting / separating the head array between a proximity position adjacent to a recording area of the recording medium and a separation position separating from the recording area;
A head array fixing means for fixing the head array at the proximity position;
The head array fixing means is provided on either the head array or the support and is provided on a gripped member extending in the contact / separation direction of the head array and on the other of the head array or the support. A gripping member that grips the gripped member and positions the gripped member in the transport direction and the width direction;
The liquid ejection unit, wherein the gripping member is capable of adjusting a gripping position of the gripped member in at least one of the transport direction and the width direction. The liquid discharge unit according to claim 1, wherein
The liquid ejection unit, wherein the gripping member is capable of adjusting a gripping position of the gripped member in the transport direction and the width direction. The liquid discharge unit according to claim 1 or 2,
The liquid discharge unit according to claim 1, wherein the support is a frame that supports the head array. In the liquid discharge unit according to any one of claims 1 to 3,
The liquid discharge unit, wherein the gripped member is a pin. In the liquid discharge unit according to any one of claims 1 to 4,
The liquid ejection unit, wherein the gripping member has at least three rotating members that hold the gripped member.   A liquid ejection apparatus comprising the liquid ejection unit according to claim 1.

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