JP2011168012A - Liquid droplet discharge head unit, liquid droplet discharge apparatus, image forming apparatus, assembling method of liquid droplet discharge head unit, and changing method, position adjustment method and jig of liquid droplet discharge head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet discharge head unit which can secure a high precision nozzle arrangement, and is inexpensive. <P>SOLUTION: A head and sub-plate assembly 22 is constituted by mounting a liquid droplet discharge head 17 on a sub-plate 20, and the liquid droplet discharge head unit is constituted by mounting the head and sub-plate assembly 22 on a base frame 15. Positioning parts 26a to 26c, and 19a to 19c to come into contact with a common positioning jig for assembling which performs mutual positioning between the sub-plate 20 and the liquid droplet discharge head 17 are provided in the sub-plate 20 and the liquid droplet discharge head 17, respectively. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a droplet discharge head such as an inkjet recording head used in, for example, an inkjet image forming apparatus (inkjet printer), and more particularly to the droplet discharge head unit.

  As is widely known, an ink jet printer supplies ink to an ink jet recording head having ink droplet ejection means for ejecting ink droplets from nozzles, and drives the ink droplet ejection means based on an input image signal. Thus, the printing apparatus forms a dot pattern image by ejecting ink from an ink jet recording head and attaching the ejected ink onto recording paper.

  As such an ink jet printer, a serial type printer that performs printing while reciprocating an ink jet recording head mounted on a carriage in a direction orthogonal to the conveyance direction of the recording paper, and a printing area for one line of printing. A line type is known in which printing is performed using an ink jet recording head provided.

  In order to increase the printing speed, a line type that does not need to scan the ink jet recording head is advantageous. In a line-type ink jet printer, a long line ink jet recording head having a structure in which a large number of ink nozzles are arranged at a fine pitch is necessary to cover the print width of one line. However, it is difficult to manufacture such a long inkjet recording head with high accuracy, and the yield is poor, which increases the manufacturing cost and is not realistic.

  Therefore, in a line-type ink jet printer, a plurality of small ink jet recording heads are arranged side by side in the width direction of the recording paper (main scanning direction) to form a line head corresponding to the printing width, and this is arranged in the recording paper transport direction (secondary direction). In the scanning direction, for example, Y, M, C, K, and the like are arranged side by side for the necessary colors.

  As a method for manufacturing such a line type ink jet recording head, for example, a method described in Patent Document 1 (Japanese Patent Laid-Open No. 10-951144) is known. In this ink jet recording head unit, an ink nozzle row used for printing of one line is divided into a plurality of divided ink nozzle rows in the line direction, and each of the divided ink nozzle rows constitutes an ink jet recording head.

  Further, the plurality of ink jet recording heads configured in this manner are arranged in a staggered manner on the base frame, and are respectively screwed to the base frame at two locations. The mounting position accuracy of each individual ink jet recording head to the base frame is very important as a factor that determines the ink droplet landing position accuracy, and high accuracy is required. Here, if the alignment of the ink jet recording head is not accurate, there may be problems such as streaks on the printed matter.

  Therefore, in order to fix the ink jet recording head to a desired position with high accuracy, an alignment plate made of glass is used when the head is assembled to the base frame as in, for example, Japanese Patent Application Laid-Open No. 2004-322606. A marker indicating the position of the nozzle hole is formed by sputtering of chromium. And the method of implement | achieving highly accurate position alignment by matching the marker which shows the position of the nozzle hole on the alignment plate of glass, and the nozzle hole which opposes it on the image is proposed.

  Further, in Patent Document 3 (Japanese Patent Laid-Open No. 2008-12747), assembly accuracy is ensured by attaching to the head side by a protruding piece for positioning that is simultaneously ground and simultaneously polished on a base frame that supports an ink jet recording head. A method has been proposed.

  However, since the head assembling method shown in Patent Document 2 is equipped with an equipment at the time of factory shipment of the ink jet printer, it is possible to assemble the head arrangement accuracy with high accuracy. However, since there is not enough equipment to replace the head due to head failure after delivery of the user, it takes a lot of time to assemble the head when replacing it, and the inkjet printer cannot be operated during that time. Therefore, there has been a problem of affecting the productivity improvement.

  In order to avoid this, in the case of a line head array having a plurality of ink jet recording heads as shown in Patent Document 3, in order to increase the nozzle arrangement accuracy, the positioning accuracy of positioning pins attached to the head plate side and Pin outer diameter accuracy, head side nozzle position and positioning point (surface) are manufactured with high accuracy, and positioning is performed with machine accuracy.

  However, when the inkjet printer is a high-speed continuous book machine, the apparatus becomes large and the base frame is 500 mm or more. Therefore, increasing the processing accuracy of the hole position deteriorates the yield, leading to an increase in cost. . This is particularly noticeable when the number of ink jet recording heads is large.

  Further, the impact of the ink droplet landing position due to the elongation of the material due to heat is large, and the elongation needs to be suppressed as much as possible. As a countermeasure, a material having a small thermal expansion may be selected. However, a vicious circle in which necessary accuracy cannot be ensured due to a problem of workability is caused.

  Furthermore, since the head is replaced when the head is broken, there is a problem that an increase in parts cost due to a high accuracy requirement of a single head to be replaced also causes an increase in running cost.

  SUMMARY OF THE INVENTION The main object of the present invention is to provide a highly accurate nozzle arrangement accuracy and an inexpensive droplet discharge head unit, droplet discharge device, image forming apparatus, droplet discharge head unit assembly method, droplet discharge head Are provided, a droplet discharge head position adjustment method, and a droplet discharge head position adjustment jig.

In order to achieve the above object, the first means of the present invention is:
A head / subplate assembly is configured by attaching a droplet discharge head on which a number of nozzle holes for discharging droplets are arranged on the subplate, and the head / subplate assembly is mounted on the base frame. A droplet discharge head unit configured as follows:
Positioning portions for making contact with a common assembly positioning jig for positioning the subplate and the droplet discharge head are provided on the subplate and the droplet discharge head, respectively. It is characterized by.

According to a second means of the present invention, in the first means,
The positioning portion provided on the sub plate is a hole portion through which the positioning protrusion provided on the assembly positioning jig passes, and the positioning portion provided on the droplet discharge head extends from the hole portion of the sub plate. The positioning surface is in contact with the protruding positioning protrusion.

A third means of the present invention is the first or second means,
The droplet discharge head includes a positioning unit that determines a position of the droplet discharge head in the main scanning direction and a positioning unit that determines a position of the droplet discharge head in the sub-scanning direction. Is.

According to a fourth means of the present invention, in the third means,
The droplet discharge head is characterized in that a plurality of positioning portions for determining the position of the droplet discharge head in the sub-scanning direction are provided at a predetermined interval.

The fifth means of the present invention is:
For example, a liquid storage unit such as a cassette or a tank that stores liquid to be discharged, a liquid droplet discharge head unit that discharges the liquid stored in the liquid storage unit as droplets on the adherend, and the liquid storage unit In the liquid droplet ejection apparatus having a liquid supply path for supplying the stored liquid to the liquid droplet ejection head unit,
The droplet discharge head unit is a droplet discharge head unit of the first to fourth means.

The sixth means of the present invention includes
A paper feeding / conveying section for conveying and supplying recording paper, an image forming section for forming an image by ejecting ink droplets onto the recording paper supplied from the paper feeding / conveying section, and the image forming section for forming an image In an image forming apparatus provided with a paper discharge conveyance unit that conveys and discharges recording paper,
In the image forming unit, the droplet discharge device of the fifth means is used.

The seventh means of the present invention is the sixth means,
The droplet discharge device is characterized in that, for example, a plurality of droplet discharge head units that discharge ink droplets of different colors such as Y, M, C, and K are arranged along the conveyance direction of the recording paper. To do.

The eighth means of the present invention is:
In a method for assembling a droplet discharge head unit in which a droplet discharge head in which a large number of nozzle holes for discharging droplets are arranged is mounted on a base frame,
A sub plate is placed on the assembly positioning jig, and a plurality of positioning projections provided on the assembly positioning jig are passed through a plurality of holes formed in the sub plate, A sub-plate positioning step for positioning the sub-plate on the assembly positioning jig by contact between the positioning protrusion and the hole;
The droplet discharge head is placed on the sub plate, and is provided on the droplet discharge head at a plurality of positioning protrusions of the assembly positioning jig protruding upward from the hole of the sub plate. A droplet discharge head positioning step for positioning the droplet discharge head on the sub-plate by contacting a plurality of positioning surfaces;
An assembly configuration step of connecting the subplate and the droplet discharge head on the assembly positioning jig to form a head / subplate assembly;
The head / sub-plate assembly is removed from the assembly positioning jig and placed on the base frame, and a predetermined position on the base frame is observed while observing the position of the nozzle hole of the droplet discharge head. And an assembly attaching step for fixing the head / sub-plate assembly.

According to a ninth means of the present invention, in the eighth means,
A plurality of positioning protrusions provided on the assembly positioning jig and a plurality of positioning surfaces provided on the droplet discharge head are:
It functions as a main scanning direction positioning means for determining the position of the droplet discharge head in the main scanning direction and a sub-scanning direction positioning means for determining the position of the droplet discharge head in the sub-scanning direction.

The tenth means of the present invention includes
A droplet discharge head in which a large number of nozzle holes for discharging droplets are arranged is positioned on a sub plate, and the droplet discharge head and the sub plate are connected to form a head / sub plate assembly.
In the method of replacing the droplet discharge head of the droplet discharge head unit in which the head / sub-plate assembly is mounted on the base frame,
Droplet discharge head replacement step of removing a droplet discharge head to be replaced from the sub-plate fixed on the base frame and placing a replacement droplet discharge head on the sub-plate;
Insert a plurality of positioning protrusions provided in the replacement positioning jig into a plurality of positioning holes formed in the base frame through a plurality of holes formed in the sub-plate. A jig positioning step for positioning the replacement positioning jig on the base frame by contact between the positioning protrusion and the positioning hole;
By bringing a plurality of positioning surfaces provided on the replacement liquid droplet ejection head into contact with a plurality of positioning projections of the replacement positioning jig protruding upward from the hole of the subplate, the subplate A droplet discharge head positioning step for positioning the replacement droplet discharge head above;
A step of detaching the replacement positioning jig from the base frame and the sub-plate, and connecting the replacement droplet-discharging head to the sub-plate.

The eleventh means of the present invention is the tenth means,
A plurality of positioning projections provided on the replacement positioning jig and a plurality of positioning surfaces provided on the replacement droplet discharge head are:
It functions as a main scanning direction positioning means for determining the position of the droplet discharge head in the main scanning direction and a sub-scanning direction positioning means for determining the position of the droplet discharge head in the sub-scanning direction.

The twelfth means of the present invention is the tenth means,
For adjusting the clearance in the sub-scanning direction between the positioning hole and the positioning projection of the replacement positioning jig inserted into the positioning hole in the vicinity of the positioning hole of the base frame, for example, an alignment frame described later This clearance adjustment member is provided.

The thirteenth means of the present invention is
A droplet discharge head in which a large number of nozzle holes for discharging droplets are arranged is positioned on a sub plate, and the droplet discharge head and the sub plate are connected to form a head / sub plate assembly.
In the method of adjusting the position of the droplet discharge head on the droplet discharge head unit in which the head / subplate assembly is mounted on the base frame,
A plurality of positioning projections for positioning in the sub-scanning direction provided in the positioning jig for position adjustment are passed through the head / subplate assembly provided with the droplet discharge head for position adjustment, and therebelow A jig positioning step for positioning the positioning jig for positioning on the base frame by inserting into a plurality of positioning holes formed in the base frame;
The head / sub-plate assembly is fixed so that the head / sub-plate assembly can be moved by loosening the connection force of the head / sub-plate assembly with the droplet discharge head for adjusting the position to the base frame. Release process;
Position adjustment in a state where a plurality of positioning surfaces provided on the droplet discharge head are in contact with a plurality of positioning projections of the positioning jig for positioning that protrudes upward from the positioning hole of the base frame. A position adjusting step for adjusting the position of the head / sub-plate assembly in the sub-scanning direction by means;
And a head / subplate assembly fixing step of fixing the head / subplate assembly to the base frame after adjustment.

The fourteenth means of the present invention includes
In a droplet discharge head position adjusting jig of a droplet discharge head unit in which a droplet discharge head in which a large number of nozzle holes for discharging droplets are arranged is mounted on a base frame via a sub-plate,
A main scanning direction positioning projection for determining the position of the droplet discharge head in the main scanning direction on one side of a holder provided in the intermediate portion of the position adjusting jig, and the sub-scanning direction of the droplet discharge head A sub-scanning direction positioning projection for determining the position of
A sub-scanning direction positioning projection for determining the position of the droplet discharge head in the sub-scanning direction is provided on the other side of the holder.

  The present invention has the above-described configuration, and it is possible to ensure high-precision nozzle arrangement accuracy, and an inexpensive droplet discharge head unit, droplet discharge device, image forming apparatus, and method for assembling the droplet discharge head unit In addition, it is possible to provide a method for replacing the droplet discharge head, a method for adjusting the position of the droplet discharge head, and a position adjusting jig for the droplet discharge head.

FIG. 2 is an exploded perspective view for explaining an ink jet recording head mounting structure according to an embodiment of the present invention. It is a top view for demonstrating the structure of the alignment plate which concerns on embodiment of this invention, and its function. It is a perspective view for demonstrating the assembly of the inkjet recording head and subplate which concern on embodiment of this invention. It is a perspective view for demonstrating the replacement | exchange method of the inkjet recording head which concerns on embodiment of this invention. It is a perspective view for explaining an adjustment method of an ink jet recording head concerning an embodiment of the present invention. FIG. 8 is a plan view of a state in which a plurality of ink jet recording heads are arranged in a staggered manner as viewed from the Z direction in FIG. 7 in the embodiment of the present invention. 1 is a schematic configuration diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention.

  Hereinafter, an assembly of an ink jet recording head in an ink jet image forming apparatus to which a line head array system according to an embodiment of the present invention is applied, a replacement system thereof, and the like will be described with reference to the drawings.

  FIG. 7 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 ink jet recording method.

  As shown in the figure, the image forming apparatus is provided with a paper feeding / conveying unit 2, one or a plurality (one in this embodiment) of image forming units 3, and a paper discharging / conveying unit 4. The image forming apparatus is configured by combining along the conveyance direction of the paper (web) 1.

  The sheet feeding / conveying unit 2 includes a nip roller 5, an infeed roller 6, a plurality of guide rollers 7, a motor (not shown) for driving the infeed roller 6, and the like. The paper feeding / conveying unit 2 has various functional units such as a web meandering correction mechanism and a web neutralization or cleaning mechanism, but these are not shown because they are not directly related to the present invention.

  The image forming unit 3 includes four (for Y, M, C, K) ink cassettes 8 at the top of the unit and four (for Y, M, C, K) mounted below the ink cassette 8. A plurality of platen rollers 10 for conveying and guiding the web 1 so as to pass through the vicinity of the lower surface of the inkjet recording head unit 9, an ink receiver 11 for trial printing, and an ink cassette 8. An ink supply path (not shown) for supplying ink to the inkjet recording head unit 9 is provided inside.

  The paper discharge transport unit 4 includes an outfeed roller 12, a nip roller 13, a plurality of guide rollers 14, a motor (not shown) for driving the outfeed roller 12, and the like.

  The present invention is characterized by the structure of the ink jet recording head unit 9 in the image forming apparatus. Next, the structure of the ink jet recording head unit 9 will be described.

FIG. 6 is a plan view of a state in which a plurality of ink jet recording heads are arranged in a staggered manner as viewed from the Z direction (nozzle surface) in FIG. 7 in the embodiment of the present invention.
An inkjet recording head 17 in which a large number of nozzle holes 16 from which ink droplets are ejected is formed in a row is formed on a flat base frame 15 in two rows in a direction perpendicular to the conveyance direction of the recording paper (web) 1 in total. Seven of them are arranged in a zigzag shape, and both end portions of each ink jet recording head 17 are fixed with screws 18a and 18b to constitute the ink jet recording head unit 9.

  The ink jet recording heads 17 can be further arranged in the main scanning direction X according to the width size of the recording paper 1 to be used.

  The ink jet recording head 17 has three positioning surfaces 19a, 19b, and 19c (shown as black circles in the figure) X in the main scanning direction (perpendicular to the recording paper transport direction) X and the sub scanning direction (recording paper transport). (Direction) The position of Y is determined.

  In this embodiment, as shown in FIG. 6, inkjet recording head units 9 a, 9 b, 9 c, 9 d for four different colors, for example, Y, M, C, K, are arranged along the conveyance direction of the recording paper 1. These are fixed to a main body frame (not shown) with screws.

  Such an ink jet recording head unit 9 needs to incorporate the ink jet recording head 17 into the base frame 15 with high positional accuracy, and when the alignment accuracy in the main scanning direction X is poor, the nozzle holes 16 are formed between the adjacent ink jet recording heads 17. When the pitch interval is shifted, streaks are generated as a result of printing, resulting in a decrease in print quality.

FIG. 1 is an exploded perspective view for explaining an ink jet recording head mounting structure according to an embodiment of the present invention.
On the end surface (side surface) of the inkjet recording head 17 having a large number of nozzle holes 16 for ejecting ink droplets, three positioning surfaces 19a, 19b, and 19c with ensured accuracy are perpendicular to the main scanning direction (X direction). Are provided vertically in the sub-scanning direction (Y direction). As shown in the figure, the positioning surface 19a is formed on the short side surface of the ink jet recording head 17 so as to be along the sub-scanning direction (Y direction), while the positioning surfaces 19b and 19c are the ink jet recording head 17. Are formed along the main scanning direction (X direction) at a predetermined interval on the longer side surface.
The positional accuracy of the positioning surfaces 19a, 19b, 19c and the nozzle hole 16 is ensured with high accuracy when the ink jet recording head 17 is assembled.

  The ink jet recording head 17 in which the nozzle hole 16 and the positioning surfaces 19a, 19b, and 19c are assembled with high accuracy is fixed to the head sub plate 20 with screws 21a and 21b, and a head sub kumi (head sub plate assembly) 22 is formed. The Note that the method for fixing the inkjet recording head 17 to the head sub-plate 20 is not limited to the screws 21a and 21b. For example, the method may be a method in which the ink-jet recording head 17 is pressed and fixed via an elastic member, but in this embodiment, the screw screws 21a and 21b are used. The fixing means by is adopted.

  The head sub-comb 22 equipped with the ink jet recording head 17 observes the position of the nozzle hole 16 with the optical microscope 23 and arranges the ink jet recording head 17 so as to be at a predetermined position, and then attaches to the base frame 15 with screws 21c and 21d. Finally, as shown in FIG. 6, an ink jet recording head unit 9 is configured in which seven ink jet recording heads 17 are arranged in a staggered manner on one base frame 15.

  Here, a method for assembling the plurality of head sub-combs 22 will be described. FIG. 3 is a view showing the assembly of the ink jet recording head 17 and the sub plate 20. For positioning the inkjet recording head 17 and the head sub-plate 20, an assembly positioning jig 24 as shown in the figure is used.

  The positioning jig 24 for assembly is mounted at positions where positioning pins 25a, 25b, and 25c processed with high precision are similarly processed with high precision. It protrudes in parallel from the upper surface of 24. Holes 26a, 26b, and 26c are formed with high accuracy at positions of the head sub-plate 20 corresponding to the positioning pins 25a, 25b, and 25c.

  By placing the head sub-plate 20 on the assembly positioning jig 24, the positioning pins 25a, 25b, 25c of the assembly positioning jig 24 pass through the holes 26a, 26b, 26c of the head sub-plate 20, It protrudes above the head sub-plate 20 so that the positional relationship between the head sub-plate 20 and the assembly positioning jig 24 is properly maintained.

  Then, the ink jet recording head 17 is placed on the head sub-plate 20, and the three positioning surfaces 19a, 19b, 19c provided on the ink jet recording head 17 are positioned on the positioning pins 25a, 25b, It abuts on the peripheral surface of 25c. As a result, the ink jet recording head 17 is positioned on the head sub-plate 20, and in this state, the ink jet recording head 17 is fixed to the head sub-plate 20 with screws 21a and 21b. By doing so, the ink jet recording head 17 is incorporated at an appropriate position with respect to the head sub plate 20, and the head sub cum 22 is obtained.

  The assembly positioning jig 24 is used as a factory assembly jig and is not incorporated into a mass-produced ink jet printer. Therefore, it is not necessary to consider the mass productivity of the assembly positioning jig 24. In addition, since the cost increase of parts is not reflected in the device price, stable high-precision products can be manufactured, and processing errors can be suppressed.

  The head sub-comb 22 thus assembled with high accuracy is aligned by the above-described optical microscope 23 (see FIG. 1) and then fixed to the base frame 15 with screws 21c and 21d.

  As will be described in detail later, the replacement / adjustment positioning jig 27 shown in FIG. 1 is used when replacing the inkjet recording head 17 at the user's site. Positioning is performed by inserting the positioning pins 28a, 28b of the replacement / adjustment positioning jig 27 into the positioning holes 26a, 26b of the head sub-kumi 22 and the positioning holes 30a, 30b of the base frame 15, and the positioning holes 30a, It is also necessary that the position 30b is highly accurate.

  However, since the base frame 15 is longer by 500 mm or more in the main scanning direction X, depending on the size of the recording paper to be used, finishing the processing accuracy at the positions of the holes 30a and 30b with high accuracy causes an increase in cost. In addition, when a material having a small thermal expansion is selected in order to suppress the elongation in the longitudinal direction of the material due to heat, workability deteriorates, and it becomes difficult to ensure the necessary accuracy.

Therefore, in this embodiment, the alignment plate 29 is used to reduce the clearance between the positioning pins 28a and 28b and the holes 30a and 30b.
As shown in FIGS. 1 and 2, elongated holes 30a and 30b are formed at positions where the positioning pins 28a and 28b of the replacement / adjustment positioning jig 27 of the base frame 15 are inserted. , 30b, alignment plates 29a, 29b are arranged. The alignment plates 29a and 29b are movable in the Y direction (sub-scanning direction) so as to be close to the holes 30a and 30b, and are finally fixed with screws 31.

  As shown in FIG. 2, the positioning pins 28a and 28b of the replacement / adjustment positioning jig 27 are inserted into the elongated holes 30a and 30b of the base frame 15, and the positioning pins in the sub-scanning direction (Y direction) which is the recording paper conveyance direction. The alignment plates 29a and 29b are moved in the Y direction so as to reduce the clearance δ between the 28a and 28b and the long holes 30a and 30b, and the alignment plates 29a and 29b are fixed with screws 31 at appropriate values. The proper clearance δ here is confirmed to be in the range of 1 to 5 μm according to the experiment results of the present inventors.

  When the clearance δ exceeds 5 μm, the nozzle position accuracy error is affected when the head is replaced, and there is a problem of image deterioration due to the deviation of the ink landing position. On the other hand, if the clearance δ is less than 1 μm, there is a problem that the pin and the hole are gnawed at the time of inserting the pin and the workability is deteriorated. For this reason, it is necessary to regulate the clearance δ within the range of 1 to 5 μm, and it is effective to use the alignment plate 29 as a means for keeping the clearance δ between the positioning pin 28 and the elongated hole 30 within the aforementioned range. is there.

  By adopting such a configuration, it is possible to suppress an increase in cost due to improvement in processing accuracy of the head plate 15.

  Next, a method for replacing the inkjet recording head 17 at the user site will be described with reference to FIGS. 4 and 5 are exploded perspective views for explaining a method of replacing and adjusting the ink jet recording head 17.

  The replacement unit of the inkjet recording head 17 is limited to the minimum unit as much as possible in order to reduce the running cost, and is performed in units of the inkjet recording head 17 and the head sub-plate 20 is not replaced. The basic idea of exchanging the ink jet recording head 17 is that the head sub-plate 20 and the base frame 15 are already positioned with high accuracy at the time of shipment from the factory. As a position reproduction method, it is possible to use a positioning jig 27 for replacement / adjustment manufactured with high accuracy.

  For example, as shown in FIG. 4, positioning pins 28a, 28a, 27b are provided on both upper and lower sides of the plate-like holder 32 so that the replacement / adjustment positioning jig 27 can be used both when the ink jet recording head is replaced and when the position adjustment described later is performed. 28b and 28c are provided. More specifically, three positioning pins 28a, 28b, and 28c are provided on one side (lower side in the figure) of the holder 32 so that positions in the main scanning direction (X direction) and the sub-scanning direction (Y direction) are determined. Two positioning pins 28a and 28b are provided on the opposite side (upper side in the figure) of the holder 32 so as to determine the position only in the sub-scanning direction (Y direction).

  Accordingly, it is not necessary to prepare a plurality of types of positioning jigs, and it is possible to deal with replacement and position adjustment of the inkjet recording head 17 with one positioning jig 27.

First, referring to FIG. 4, the case where the positioning in the main scanning direction (X direction) and the sub-scanning direction (Y direction) is performed with the three positioning pins 28a, 28b, 28c will be described.
As described above, the head sub-plate 20 is positioned and fixed with high precision by the screws 21c and 21d on the base frame 15 at the time of shipment from the factory, and only the inkjet recording head 17 that needs to be replaced is replaced.

  First, the screws 21 a and 21 b are removed, the old ink jet recording head 17 is removed from the head sub plate 20, and the new ink jet recording head 17 is placed on the head sub plate 20. Next, the positioning pins 28a, 28b, 28c of the replacement / adjustment positioning jig 27 are formed in the positioning holes 30a, 30b of the base frame 15 and the base frame 15 through the positioning holes 26a, 26b, 26c of the head sub-plate 20. Is inserted into the opening 39 (see FIG. 5).

  In this state, the ink jet recording head 17 is slightly slid on the head sub-plate 20, and the positioning surfaces 19a, 19b, 19c of the ink jet recording head 17 are rotated around the positioning pins 28a, 28b, 28c of the positioning jig 27 for replacement / adjustment. Press against the surface. By this pressing, the ink jet recording head 17 is positioned on the head sub plate 20 in the main scanning direction (X direction) and the sub scanning direction (Y direction) at the same time, and the ink jet recording head 17 is attached to the head sub plate 20 by screws 21a and 28b. Secure on top.

  At this time, the positioning restricts the angle of the ink jet recording head 17 at two points in the sub-scanning direction, and determines the position in the main scanning direction at one point in the main scanning direction. As a result, the position of the inkjet recording head 17 is determined with high accuracy with respect to the positioning pins 28a, 28b, 28c of the replacement / adjustment positioning jig 27 without play. Therefore, since it is only necessary to press the ink jet recording head 17, the position can be aligned in a very short time.

  Again, by using the positioning jig 27, the cost of parts of the inkjet recording head 17 and the head plate 20 is not increased more than necessary, and the positioning jig 27 is not mounted on the inkjet printer, so that mass production is possible. Therefore, it is possible to manufacture a stable and highly accurate product, and processing errors can be suppressed.

  On the other hand, as an ink ejection characteristic of an ink jet printer, bending (ink is ejected basically vertically from the nozzle hole 16 to the recording paper 1, but depending on the processing state of the nozzle hole 16, it is curved and ejected). Ink landing position deviation may occur due to. In this case, even if the arrangement accuracy of the nozzle holes 16 is mechanically ensured, there may be a case where a positional deviation occurs in the final image on the recording paper 1 due to the bending described above.

Next, a method for avoiding this problem will be described.
As described with reference to FIG. 4, after the replacement of the new ink jet recording head 17 is completed at the user, test printing is performed based on the test pattern in which the landing position deviation can be confirmed. When it is determined that the ink droplet landing position of the replaced inkjet recording head 17 is deviated from the above-described test results, as the positional deviation correction method, the ink of the inkjet recording head 17 is used in the sub-scanning direction (Y direction). Although correction is possible by changing the droplet ejection timing, it is necessary to mechanically adjust the position of the inkjet recording head 17 in the main scanning direction (X direction).

Next, a method for adjusting the position of the ink jet recording head 17 in the main scanning direction will be described with reference to FIG.
As shown in FIG. 5, the positioning jig 27 uses the side where there are two positioning pins 28a and 28b for determining the position in the sub-scanning direction. That is, the positioning jig 27 is used opposite to that shown in FIG. With the positioning pins 28a, 28b of the replacement / adjustment positioning jig 27 facing down, they are inserted into the positioning holes 26a, 26b provided in the head sub plate 20 of the head sub kumi 22 to the positioning holes 30a, 30b of the base frame 15. To penetrate.

  After the positioning pins 28a and 28b are inserted, the screws 21c and 21d fixing the head sub-comb 22 are loosened. In this state, the eccentric cam 33 is used to finely adjust the position of the head sub-comb 22 in the X direction in the figure.

  As shown in FIG. 5, the eccentric cam 33 has a columnar shape or a disk shape, and has an appropriate eccentricity amount e with respect to the shaft 36 provided at the lower portion thereof. In addition, a drive-side shaft 38 having an engagement groove 37 with which a tip portion of a driver or the like is engaged is integrally provided on the eccentric cam 33.

  On the other hand, a square hole 34 is formed in the head sub kumi 22 (bed sub plate 20), and an eccentric cam insertion hole 35 is formed at a position corresponding to the square hole 34 of the base frame 15. For example, as shown in FIG. 1, the square hole 34 has a substantially square planar shape, and one side of the square hole 34 is designed to be substantially the same as the diameter of the eccentric cam 33. The inner diameter of 35 is designed to be approximately the same as the outer diameter of the shaft 36.

  The shaft 36 is inserted into the eccentric cam insertion hole 35 of the base frame 15 from the square hole 34 of the head sub-comb 22 (bed sub-plate 20), and accordingly the eccentric cam 33 is inserted into the square hole of the head sub-comb 22 (bed sub-plate 20). 34 is fitted.

  Then, by inserting the tip portion of a driver or the like into the engagement groove 37 and rotating the drive side shaft 38, the eccentric cam 33 rotates with the eccentric amount e around the shaft 36. Can be finely adjusted in the X direction in the figure. When the head sub-comb 22 is slid, the positioning surfaces 19b and 19c of the head sub-comb 22 move along the positioning pins 28a and 28b of the replacement / adjustment positioning jig 27 installed in advance. The position does not change.

  After the adjustment, the screws 21c and 21d are tightened to fix the head sub-kumi 22 on the base frame 15, and a test pattern for detecting the landing position deviation is printed again, and it is confirmed that the fine adjustment of the head sub-kumi 22 has been completed. finish.

  In the above-described embodiment, the positioning jigs 24 and 27 having the positioning pins 25a to 25c and 28a to 28c are used. However, instead of the positioning pins 25a to 25c and 28a to 28c, other positioning pins or protrusions are used. It is also possible to use a shaped positioning protrusion.

  In the above embodiment, the square hole 34 is formed inside the head sub-plate 20. Instead of the square hole 34, for example, a cut portion cut in the Y direction from the end of the head sub-plate 20 is formed, and the cut is made. It is also possible to fit the eccentric cam 33 to the insertion portion.

  In the above-described embodiment, the cam mechanism is used as the position adjusting means. However, it is also possible to use position adjusting means of other mechanisms such as moving the head sub-comb 22 by rotating a screw.

  In the above embodiment, the case where the present invention is applied to an ink jet printer (image forming apparatus) has been described. However, the present invention is not limited to this, for example, a three-dimensional modeling apparatus for manufacturing a three-dimensional modeled object. The present invention can also be applied to other technical fields.

  1: recording paper, 2: paper feed conveyance unit, 3: image forming unit, 4: paper discharge conveyance unit, 9, 9a to 9d: ink jet recording head unit, 15: base frame, 16: nozzle hole, 17: ink jet recording Head, 19a to 19c: positioning surface, 20: sub plate, 22: head sub kumi (head / sub plate assembly), 24: positioning jig for assembly, 25a to 25c: positioning pin, 26a to 26c: hole, 27: exchange Adjustment positioning jig, 28a to 28c: positioning pin, 29: alignment plate, 30a, 30b: positioning hole, 32: holder, 33: eccentric cam, 34: square hole, 35: eccentric cam insertion hole, 36 : Shaft, 37: engagement groove, 38: driving shaft, X: main scanning direction, Y: sub main scanning direction.

JP-A-10-951144 JP 2004-322606 A JP 2008-12747 A

Claims (14)

A head / subplate assembly is configured by attaching a droplet discharge head on which a number of nozzle holes for discharging droplets are arranged on the subplate, and the head / subplate assembly is mounted on the base frame. A droplet discharge head unit configured as follows:
Positioning portions for making contact with a common assembly positioning jig for positioning the subplate and the droplet discharge head are provided on the subplate and the droplet discharge head, respectively. A droplet discharge head unit characterized by   2. The droplet discharge head unit according to claim 1, wherein the positioning portion provided on the sub-plate is a hole through which a positioning protrusion provided on the assembly positioning jig passes, The droplet discharge head unit according to claim 1, wherein the positioning portion provided is a positioning surface that contacts a positioning protrusion protruding from the hole of the sub-plate.   3. The droplet discharge head unit according to claim 1, wherein the droplet discharge head includes a positioning unit that determines a position of the droplet discharge head in the main scanning direction, and a sub-scanning direction of the droplet discharge head. A droplet discharge head unit comprising a positioning portion for determining a position.   4. The liquid droplet ejection head unit according to claim 3, wherein the liquid droplet ejection head is provided with a plurality of positioning portions that determine the position of the liquid droplet ejection head in the sub-scanning direction at a predetermined interval. A droplet discharge head unit characterized by A liquid storage part for storing the liquid to be discharged, a liquid droplet discharge head unit for discharging the liquid stored in the liquid storage part as droplets on the adherend, and the liquid stored in the liquid storage part In the liquid droplet ejection apparatus having a liquid supply path for supplying the liquid droplet ejection head unit,
5. A droplet discharge apparatus, wherein the droplet discharge head unit is the droplet discharge head unit according to any one of claims 1 to 4. A paper feeding / conveying section for conveying and supplying recording paper, an image forming section for forming an image by ejecting ink droplets onto the recording paper supplied from the paper feeding / conveying section, and the image forming section for forming an image In an image forming apparatus provided with a paper discharge conveyance unit that conveys and discharges recording paper,
An image forming apparatus using the droplet discharge device according to claim 5 in the image forming unit. The image forming apparatus according to claim 6.
An image forming apparatus, wherein the droplet discharge device includes a plurality of droplet discharge head units that discharge ink droplets of different colors along a conveyance direction of the recording paper. In a method for assembling a droplet discharge head unit in which a droplet discharge head in which a large number of nozzle holes for discharging droplets are arranged is mounted on a base frame,
A sub plate is placed on the assembly positioning jig, and a plurality of positioning projections provided on the assembly positioning jig are passed through a plurality of holes formed in the sub plate, A sub-plate positioning step for positioning the sub-plate on the assembly positioning jig by contact between the positioning protrusion and the hole;
The droplet discharge head is placed on the sub plate, and is provided on the droplet discharge head at a plurality of positioning protrusions of the assembly positioning jig protruding upward from the hole of the sub plate. A droplet discharge head positioning step for positioning the droplet discharge head on the sub-plate by contacting a plurality of positioning surfaces;
An assembly configuration step of connecting the subplate and the droplet discharge head on the assembly positioning jig to form a head / subplate assembly;
The head / sub-plate assembly is removed from the assembly positioning jig and placed on the base frame, and a predetermined position on the base frame is observed while observing the position of the nozzle hole of the droplet discharge head. An assembly mounting step of fixing the head / subplate assembly to a liquid droplet discharge head unit assembly method. In the assembly method of the droplet discharge head unit according to claim 8,
A plurality of positioning protrusions provided on the assembly positioning jig and a plurality of positioning surfaces provided on the droplet discharge head are:
A droplet discharge head that functions as a main scanning direction positioning unit that determines a position of the droplet discharge head in the main scanning direction and a sub-scanning direction positioning unit that determines a position of the droplet discharge head in the sub-scanning direction. How to assemble the unit. A droplet discharge head in which a large number of nozzle holes for discharging droplets are arranged is positioned on a sub plate, and the droplet discharge head and the sub plate are connected to form a head / sub plate assembly.
In the method of replacing the droplet discharge head of the droplet discharge head unit in which the head / sub-plate assembly is mounted on the base frame,
Droplet discharge head replacement step of removing a droplet discharge head to be replaced from the sub-plate fixed on the base frame and placing a replacement droplet discharge head on the sub-plate;
Insert a plurality of positioning protrusions provided in the replacement positioning jig into a plurality of positioning holes formed in the base frame through a plurality of holes formed in the sub-plate. A jig positioning step for positioning the replacement positioning jig on the base frame by contact between the positioning protrusion and the positioning hole;
By bringing a plurality of positioning surfaces provided on the replacement liquid droplet ejection head into contact with a plurality of positioning projections of the replacement positioning jig protruding upward from the hole of the subplate, the subplate A droplet discharge head positioning step for positioning the replacement droplet discharge head above;
A droplet discharge head connecting step of removing the replacement positioning jig from the base frame and the sub plate and connecting the replacement droplet discharge head to the sub plate. method of exchange. The method of replacing a droplet discharge head according to claim 10,
A plurality of positioning projections provided on the replacement positioning jig and a plurality of positioning surfaces provided on the replacement droplet discharge head are:
A droplet discharge head that functions as a main scanning direction positioning unit that determines a position of the droplet discharge head in the main scanning direction and a sub-scanning direction positioning unit that determines a position of the droplet discharge head in the sub-scanning direction. Exchange method. The method of replacing a droplet discharge head according to claim 10,
Provided in the vicinity of the positioning hole of the base frame is a clearance adjustment member for adjusting the clearance in the sub-scanning direction between the positioning hole and the positioning protrusion of the replacement positioning jig inserted into the positioning hole. A method for replacing a droplet discharge head. A droplet discharge head in which a large number of nozzle holes for discharging droplets are arranged is positioned on a sub plate, and the droplet discharge head and the sub plate are connected to form a head / sub plate assembly.
In the method of adjusting the position of the droplet discharge head on the droplet discharge head unit in which the head / subplate assembly is mounted on the base frame,
A plurality of positioning projections for positioning in the sub-scanning direction provided in the positioning jig for position adjustment are passed through the head / subplate assembly provided with the droplet discharge head for position adjustment, and therebelow A jig positioning step for positioning the positioning jig for positioning on the base frame by inserting into a plurality of positioning holes formed in the base frame;
The head / sub-plate assembly is fixed so that the head / sub-plate assembly can be moved by loosening the connection force of the head / sub-plate assembly with the droplet discharge head for adjusting the position to the base frame. Release process;
Position adjustment in a state where a plurality of positioning surfaces provided on the droplet discharge head are in contact with a plurality of positioning projections of the positioning jig for positioning that protrudes upward from the positioning hole of the base frame. A position adjusting step for adjusting the position of the head / sub-plate assembly in the sub-scanning direction by means;
And a head / subplate assembly fixing step of fixing the head / subplate assembly to the base frame after adjustment. In a droplet discharge head position adjusting jig of a droplet discharge head unit in which a droplet discharge head in which a large number of nozzle holes for discharging droplets are arranged is mounted on a base frame via a sub-plate,
A main scanning direction positioning projection for determining the position of the droplet discharge head in the main scanning direction on one side of a holder provided in the intermediate portion of the position adjusting jig, and the sub-scanning direction of the droplet discharge head A sub-scanning direction positioning projection for determining the position of
A sub-scanning direction positioning projection for determining a sub-scanning direction position of the droplet discharge head is provided on the other side of the holder.

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