JP2012016873A - Liquid droplet discharge head unit, and assembling method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head exchanger which ensures a position reproducibility when heads are exchanged in head exchange in a printer, can decrease exchange work man-hours, and can be manufactured simply at a low cost.SOLUTION: The liquid droplet discharge head unit is comprised of a liquid droplet discharge head, having a nozzle surface with many nozzle holes for discharging liquid droplets and equipped with a reference plane for specifying a nozzle position at two points on one of two planes perpendicular to the nozzle surface and a nozzle position at one point on the other plane, and a liquid droplet discharge head holding member, having a position reference butting member for fixing the liquid droplet discharge head by specifying the nozzle position by butting the reference plane of the liquid droplet discharge head at three points, wherein the liquid droplet discharge head is butted to the position reference butting member of the liquid droplet discharge head holding member by applying a load simultaneously to opposed two planes by a load applying member which contacts to the opposed two planes each opposed to the reference plane, whereby the liquid droplet discharge head is positioned and fixed to the discharge head holding member.

Description

  The present invention relates to a droplet discharge head unit and an assembly method thereof.

  In a line-type ink jet printer that prints by arranging a plurality of ink jet recording heads (hereinafter abbreviated as heads) in the main scanning direction, the head is aligned on a flat frame and then fixed with screws. wear. If this alignment is not accurate, problems such as streaks appear in the printed image. Also, if a problem occurs in the head, the head to be replaced is similarly positioned and assembled by fixing with screws.

  In particular, a high-speed continuous entry machine is required to have a technology that can be assembled with high alignment accuracy. In addition, a technique for shortening the replacement time is also required in order to minimize the downtime of the machine due to the replacement. Currently, several techniques for positioning the head with high accuracy are already known.

  However, the head alignment technology used in conventional line-type ink jet printers is capable of aligning the head with high accuracy when assembled at the factory and when the head is replaced due to a failure. Often complex. In addition, when fixing the head after alignment, for example, in the case of screw fixing, there is a problem of poor position reproducibility, such as deviation from the aligned state due to the rotational action by screw tightening. When the head alignment accuracy and the position reproducibility after fixing the head are low, the landing position of the ink is displaced, resulting in a problem in image quality. At this time, it is necessary to adjust the position of the head again, resulting in an increase in work man-hours and downtime.

  In line-type ink jet printers, a plurality of heads are arranged adjacent to each other with a rule (such as a staggered pattern), so the space for mounting the positioning mechanism is small, and the mechanism has sufficient functions. It is difficult to have. Furthermore, since a line type ink jet printer has a plurality of heads, the number of mechanisms required is the same as the number of heads, which greatly affects the cost.

  Patent Document 1 discloses a configuration in which an alignment plate provided with a V-shaped notch or the like is attached to the head for the purpose of both shortening the work time when replacing the head and achieving high alignment accuracy. Certainly, it is excellent in that the alignment is performed with a small number of man-hours. However, as described above, the problem that the mechanism is complicated and the mounting space is increased, and the problem that the position reproducibility is lowered due to the displacement when the head is fixed cannot be solved.

  Patent Document 2 discloses a configuration in which the head mount is adjusted with two tapered screws. In adjusting the position of the head mount, a pressing force is generated by rotating a taper-shaped screw and used. However, a screw tightening operation is always generated for each taper-shaped screw. Therefore, there is a problem that the work takes time as many as the number of tapered screws.

  The object of the present invention is to solve the above problems in head replacement in a line type ink jet printer, while ensuring position reproducibility at the time of head replacement, reducing the number of replacement work, and being small, simple and low cost. It is an object of the present invention to provide a head exchange mechanism that can be manufactured.

  The liquid droplet ejection head unit of the present invention has a nozzle surface having a large number of nozzle holes for ejecting liquid droplets, two on one surface of two planes perpendicular to the nozzle surface, and on the other surface. A droplet discharge head provided with a reference surface for defining one nozzle position and a position for fixing the droplet discharge head by abutting the reference surfaces of the three droplet discharge heads to define the nozzle position A droplet discharge head unit composed of a droplet discharge head holding member provided with a reference abutting member, wherein the load is applied to the opposite two planes simultaneously by a load applying member that abuts the opposite two planes respectively facing the reference plane. Is provided, the droplet discharge head is abutted against the position reference abutting member of the droplet discharge head holding member, and the droplet discharge head is positioned and fixed to the discharge head holding member.

  According to the present invention, it is possible to perform head replacement with high positioning accuracy in a short time, and with the simple mechanism, it is possible to perform at low cost.

FIG. 2 is a detailed configuration diagram around an ink jet recording head according to an embodiment of the present invention. It is a figure of the alignment operation description (the 1) which concerns on embodiment of this invention. It is a figure of the alignment operation description (the 2) which concerns on embodiment of this invention. It is a figure of the alignment operation description (the 3) which concerns on embodiment of this invention. It is a figure of the alignment operation description (the 4) which concerns on embodiment of this invention. It is a figure of the alignment operation description (the 5) which concerns on embodiment of this invention. It is a figure of the alignment operation description (the 6) which concerns on embodiment of this invention. It is a figure of the alignment operation description (the 7) which concerns on embodiment of this invention. It is a figure of the alignment operation description (the 8) which concerns on embodiment of this invention. It is a figure of alignment operation description (the 9) which concerns on embodiment of this invention. It is a figure of the alignment operation description (the 10) which concerns on embodiment of this invention. 1 is a schematic configuration diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. 1 is an overall view of an ink jet recording head unit according to an embodiment of the present invention.

  An embodiment of the present invention will be described. The present invention has the following features when positioning and assembling at the time of head replacement. That is, a plurality of positioning pins that determine positions in the main scanning and sub-scanning directions of the ink jet recording head and a member that applies a load for pressing the ink jet recording head to each positioning pin are provided. Further, in the above unit, the load applying member is configured to press the recording head simultaneously in two directions against a plurality of positioning pins in the main scanning direction and the sub-scanning direction.

  Further, the load applying member is configured to be removable from the unit. The shape of the load applying member is L-shaped. In addition, the load applying member has a protruding portion in which the shape of the recording head pressing portion is a convex shape. Further, the direction in which the recording head is pressed to the positioning pins in the main scanning and sub-scanning directions via the load applying member is one direction, and the position to apply the load is the recording head and the main scanning, and It is a surface facing the surface where each positioning pin in the sub-scanning direction contacts.

  Moreover, it is using the member provided with the taper part for operation of said load provision member. Further, the height of the load applying member is lower than the height of the positioning pin. Further, the pressing position of the recording head pressed by the load applying member has a convex or concave shape. These features of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 shows a state in which the base frame 7 and the head 1 are separated in the ink jet recording head unit 109 (see FIG. 12) when the ink jet recording head 1 (hereinafter, head 1) is replaced. The base frame 7 to which the head 1 is fixed has one abutment pin 3a that determines the position in the main scanning direction (head long side direction) and two abutments that determine the position in the sub-scanning direction (head short side direction). Pins 3b and 3c are press-fitted.

  For alignment of the head 1, an L-shaped jig 8 (hereinafter referred to as “L-shaped jig 8”) and a screw 5 with a tapered portion are used as means for applying a load to the L-shaped jig 8. By rotating the screw 5 with the taper portion, the taper portion can move along a direction perpendicular to the main surface of the base frame 7. At the time of alignment, the taper portion screw 5 is rotated so as to move downward. When the tapered portion is lowered, the L-shaped jig 8 comes into contact, and the L-shaped jig 8 receives a load from the screw 5 with the tapered portion at the contact portion. The L-shaped jig 8 contacts the head 1 at two points and applies a load. The head 1 is pressed against the abutting pins 3a, 3b, and 3c by this load, and is in an aligned state.

  After alignment, the head 1 is fixed to the base frame 7 by the head fixing screws 2a and 2b. At the time of fixing the screw, the head 1 tries to rotate and move from the correctly aligned state by the frictional force received from the screw seating surface, but is restrained by the L-shaped jig 8 in a state where a load is applied by the screw 5 with the taper portion. Therefore, this rotational movement can be prevented.

  Since the screw 5 with the taper portion for applying a load to the L-shaped jig 8 is caused to move up and down by the rotation of the screw, the state where the load is applied is maintained unless the screw is rotated. As a result, the work of fixing the screw with the other hand while the head is in contact can be eliminated, so that the work efficiency can be expected to be improved and the replacement can be performed in a short time.

  The means for applying a load to the L-shaped jig 8 may be other than the taper portion screw 5 as long as the above-described load can be maintained. In addition, since the L-shaped jig 8 and the taper-attached screw 5 are used only at the time of head replacement, even if there are a plurality of heads, a significant cost increase can be avoided.

  2 to 11 are diagrams for explaining one of the embodiments of the head alignment mechanism in the ink jet recording head unit 109 (see FIG. 12). When the head 1 is replaced, the head 1 and the L-shaped jig 8 are arranged with respect to the three abutting pins 3a, 3b, 3c as shown in FIG. At this time, the head 1 is not in contact with the L-shaped jig 8 and the three abutting pins 3a, 3b, 3c, and is not aligned. Further, the L-shaped jig 8 is in a state where no load is applied from the screw 5 with the tapered portion.

  From the state of FIG. 2, the taper portion 5 b of the screw 5 with the taper portion is rotated so as to move downward along a direction perpendicular to the main surface of the base frame 7. At this time, a load is applied in a direction orthogonal to the contact surface 18 of the tapered portion 5b and the L-shaped jig 8. Due to this load, the L-shaped jig 8 is translated in the main scanning direction as shown in FIG. 3 and is in contact with the surface 15 d formed by the protruding portion 9 a provided on the L-shaped jig 8 and the short side of the head 1. It becomes the state of 3.

  Further, when a load is continuously applied to the L-shaped jig 8, the head 1 is placed on the L-shaped jig around the contact point of the surface 15d formed by the protruding portion 9a provided on the L-shaped jig 8 and the short side of the head 1 described above. The other protruding portion 9b provided in 8 rotates and moves until it comes into contact with the surface 15c formed by the long side of the head 1, and the state shown in FIG.

  When a load is further applied to the L-shaped jig 8 from the state of FIG. 4, the head 1 is applied with a load from the surfaces 15d and 15c of the head 1 that come into contact with the protruding portions 9a and 9b provided on the L-shaped jig 8. 7 Move on. The head 1 moves until it comes into contact with the abutting pins 3a, 3b, 3c, and the head alignment is completed.

  As shown in FIG. 5 or FIG. 6, it is desirable that the convex portion 12 or the concave portion 13 is provided on the surface 15 c that contacts the protruding portion 9 b provided on the L-shaped jig 8. This is because the L-shaped jig 8 slides on the surfaces 15c and 15d when the coefficient of friction on the surfaces 15c and 15d where the protrusions 9a and 9b contact the head 1 is small, and the L-shaped jig 8 is as shown in FIG. It is because it will come off.

  Further, when the convex portion 12 or the concave portion 13 is provided, the load application position to the L-shaped jig 8 is a straight line passing through the contact point between the protruding portion 9a and the surface 15d and parallel to the surface 15c, as shown in FIGS. It is desirable to take between A and the straight line B which passes the contact point of the convex part 12 or the recessed part 13, and the L-shaped jig 8, and is parallel to the surface 15c. If the load application position is out of this range, the L-shaped jig 8 moves away from the head 1 around the contact point between the protruding portion 9a and the surface 15d or the contact point between the L-shaped jig 8 and the convex portion 12 or the concave portion 13. This is because it rotates.

  Further, when a load is applied to the head 1 by the L-shaped jig 8, it is desirable that the height L2 of the L-shaped jig 8 is lower than the height L1 of the abutting pins 3a, 3b, 3c as shown in FIG. This is because when the contact point between the L-shaped jig 8 and the head 1 when applying a load is higher than the contact point between the abutting pins 3a, 3b and 3c, a moment for lifting the head 1 in the counterclockwise direction is generated. This is because it adversely affects the alignment. By making the height L2 of the L-shaped jig 8 lower than the height L1 of the abutting pins 3a, 3b, 3c, it is possible to improve the alignment accuracy and the position reproducibility.

  As described above, the head alignment work can be applied to the head 1 with a load necessary to press the positioning pin in the two directions of main scanning and sub-scanning only by operating the screw 5 with the tapered portion. Because the working time can be done in a short time, the machine downtime can be greatly reduced. Furthermore, since the number of components is small and the jig is removable, the cost increase can be minimized.

  FIG. 12 is a schematic configuration diagram showing the overall configuration of the image forming apparatus according to the embodiment of the present invention. The image forming apparatus according to this embodiment is an apparatus that forms an image by an inkjet method. As shown in FIG. 12, the image forming apparatus is provided with a sheet feeding / conveying unit 102, one or a plurality (one in this embodiment) of image forming units 103, and a sheet discharging / conveying unit 104. Are combined along the conveyance direction of the recording paper (web) 101 to constitute an image forming apparatus.

  The sheet feeding / conveying unit 102 includes a nip roller 105, an infeed roller 106, a plurality of guide rollers 107, a motor (not shown) for driving the infeed roller 106, and the like. The paper feeding / conveying unit 102 has various functional units such as a web meandering correction mechanism and a web static elimination or cleaning mechanism, but these are not shown because they are not directly related to the present invention.

  The image forming unit 103 includes four (for Y, M, C, and K) ink cassettes 108 at the top of the unit, and four (for Y, M, C, and K) mounted at the bottom of the ink cassette 108. Ink jet recording head unit 109, a plurality of platen rollers 110 for conveying and guiding the web 101 so as to pass through the vicinity of the lower surface of the ink jet recording head unit 109, an ink receiver 111 for ink trial hitting, and ink in the ink cassette 108 An ink supply path (not shown) for supplying the ink to the ink jet recording head unit 109 is provided inside.

  The paper discharge conveyance unit 104 includes an outfeed roller 112, a nip roller 113, a plurality of guide rollers 114, a motor (not shown) for driving the outfeed roller 112, and the like.

  FIG. 13 is a diagram for explaining the ink jet recording head unit 109. In the embodiment of the present invention, a plurality (five in this embodiment) of inkjet recording heads 1 (hereinafter abbreviated as heads 1) are arranged in a staggered manner on the flat base frame 7 in the inkjet recording head unit 109. ing. The number of heads 1 may be increased or decreased according to the width of the web and the number of colors used.

  As an effect of the present invention, in a line type ink jet printer, head replacement can be performed for a short time with high alignment accuracy (reduction of downtime). Further, by using a simple mechanism, high alignment accuracy can be achieved at low cost. The reason for this is that when the head is aligned by contacting the abutting pin that determines the position in the main scanning direction and the abutting pin that determines the position in the sub-scanning direction, the contact between the head and the abutting pin This is because the process of applying a load to the head necessary for the process can be performed using a simple jig.

DESCRIPTION OF SYMBOLS 1 Inkjet recording head 2a Head fixing screw 2b Head fixing screw 3a Butting pin 3b Butting pin 3c Butting pin 5 Screw with taper part 7 Base frame 8 L-shaped jig 9a Protruding part 9b Protruding part 101 Recording paper (web)
DESCRIPTION OF SYMBOLS 102 Paper feed conveyance unit 103 Image forming unit 104 Paper discharge conveyance unit 105 Nip roller 106 Infeed roller 107 Several guide rollers 108 Ink cassette 109 Inkjet recording head unit 110 Platen roller 111 Ink receiving 112 Outfeed roller

JP 2008-296518 A Japanese Patent Laid-Open No. 2007-076176

Claims (8)

It has a nozzle surface having a large number of nozzle holes for discharging droplets, and defines two nozzle positions on one surface of two planes perpendicular to the nozzle surface and one nozzle position on the other surface. A droplet discharge head provided with a reference surface;
A droplet discharge head holding member provided with a position reference abutting member for abutting the reference surfaces of the three droplet discharge heads to define a nozzle position and fixing the droplet discharge head;
In the droplet discharge head unit composed of
A position reference abutting member of the droplet discharge head holding member is provided by simultaneously applying a load to the two opposite planes by a load applying member that abuts against the opposite two planes respectively facing the reference plane. A droplet discharge head unit, wherein the droplet discharge head is positioned and fixed to the discharge head holding member. In the droplet discharge head unit according to claim 1,
The shape of the load applying member is L-shaped. The droplet discharge head unit according to claim 1 or 2,
A droplet discharge head unit, wherein the load applying member is provided with a plurality of protrusions. In the liquid droplet ejection head unit according to any one of claims 1 to 3,
The liquid droplet ejection head unit is characterized in that a load direction applied to the load applying member is one direction. In the liquid droplet ejection head unit according to any one of claims 1 to 4,
A droplet discharge head unit characterized in that a cylindrical member provided with a tapered portion is moved in a direction substantially perpendicular to the pressing direction for the pressing operation of the load applying member. In the liquid droplet ejection head unit according to any one of claims 1 to 5,
The height of the load applying member that abuts against the two opposing planes and applies a load in a direction parallel to the droplet discharging direction is lower than the height of the position reference abutting member. Head unit. In the droplet discharge head unit according to any one of claims 1 to 6,
A droplet discharge head unit, wherein a pressing position of the droplet discharge head pressed by the load applying member is convex or concave. 2. The method of assembling a droplet discharge head unit according to claim 1, further comprising the step of using the load applying member as a detachable jig and fixing the load applying member to the discharge head holding member. Assembly method.

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