JP2012161992A - Positioning mechanism of liquid droplet ejection head, liquid droplet ejection apparatus, image forming apparatus, and method for positioning and replacing liquid droplet ejection head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positioning mechanism of a liquid droplet ejection head, which is capable of ensuring nozzle arrangement with high accuracy.SOLUTION: The positioning mechanism has: an ejection head 17 with a reference plane 19 arranged at an orthogonal side; a head mounting member 15 with an abutment part 25 of the reference plane 19; and a head pressing-sliding jig 21 for pressing the reference plane 19 to the abutment part side. The head pressing-sliding jig 21 has a conical part 26, and by screwing in the head pressing-sliding jig 21, the liquid droplet ejection head 17 is fixed to the head mounting member 15, while being sandwiched between the conical part 26 and the abutment part 25.

Description

  The present invention relates to a droplet discharge head positioning mechanism, a droplet discharge device, an image forming apparatus, a droplet discharge head positioning method, and an exchange method.

  2. Description of the Related Art 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 an image to which ink droplet ejection means of the ink jet recording head is input A printing apparatus (image forming apparatus) that forms a dot pattern image by ejecting ink from an ink-jet recording head by driving based on a signal and attaching the ejected ink onto a recording sheet.

  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. There is known a line type that performs printing using an ink-jet recording head equipped with the above.

  In order to increase the printing speed, a line type that does not require scanning of the ink-jet recording head is advantageous. In a line-type inkjet 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 printing width for one line. However, it is difficult to manufacture such a long ink-jet recording head with high accuracy and the yield is poor, which increases the manufacturing cost and is not realistic.

  For this reason, in a line-type ink jet printer, a plurality of small recording head units are arranged in the width direction (main scanning direction) of the recording paper to form a line-type head for the printing width, which is arranged in the conveyance direction of the recording paper ( In the sub-scanning direction), for example, necessary colors such as magenta, cyan, blue, and black are arranged side by side.

As a method for manufacturing such a line-type head, for example, a method described in JP-A-10-951144 (Patent Document 1) 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 divided ink nozzle row 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 plate, and are screwed to the base plate at two locations respectively. The mounting position accuracy of each individual ink jet recording head to the base plate is very important as a factor for determining the landing position accuracy, and high accuracy is required. Here, if the alignment of the ink-jet recording head is not accurate, problems such as streaks may occur in the printed matter.

  Therefore, in order to fix the ink jet recording head to a desired position with high accuracy, when assembling the ink jet recording head to the support base plate, for example, as disclosed in Japanese Patent Application Laid-Open No. 2004-322606 (Patent Document 2), glass is used. A marker indicating the position of the nozzle hole is formed on the resulting alignment plate by sputtering of chromium. There has been proposed a method for realizing highly accurate alignment by aligning the marker and the nozzle hole opposite to the marker on the image.

  Japanese Patent Application Laid-Open No. 2008-296518 (Patent Document 3) discloses an alignment plate having a V-shaped notch or the like for the purpose of shortening the working time when replacing the head and achieving high alignment accuracy. A configuration attached to the head is disclosed.

  Furthermore, Japanese Patent No. 3894000 (Patent Document 4) discloses a method of assembling a line-type head, and Japanese Patent Application Laid-Open No. 2007-76176 (Patent Document 5) discloses a method related to a method of adjusting the position of the line-type head. .

  However, since the head assembling method shown in Patent Document 2 is equipped with facilities at the time of shipment from the factory, it is possible to arrange and assemble the inkjet recording head with high accuracy. There is not enough equipment when replacing the head due to failure, etc., so it takes a lot of time to assemble the head when replacing it, and the inkjet printer cannot be operated during that time, affecting the printing work. was there.

  In order to avoid such a situation, in the case of a line type head array having a plurality of recording heads, in order to increase the nozzle arrangement accuracy, the positioning accuracy and pin outer diameter accuracy of the positioning pins attached to the head plate side and the head side accuracy are improved. The 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 head base plate is 500 mm or more. Therefore, increasing the processing accuracy of the hole position results in poor yield, leading to an increase in cost. . In particular, it becomes more prominent when the number of recording heads increases.

  In addition, since the head is replaced when the head fails, there is a problem that an increase in the cost of parts due to the high accuracy requirement of the single head to be replaced also increases the running cost.

  The patent document 3 has an advantage that the alignment of the ink-jet recording head can be performed with a small number of man-hours. However, the mechanism is complicated, and it is difficult to arrange a plurality of heads adjacent to each other in a small space with a certain rule due to the mounting of the positioning mechanism. . Further, it has not been possible to solve the problem that the position reproducibility is lowered due to a shift when the head is fixed with a screw or the like when replacing the head.

  Patent Document 4 describes an assembling method using an assembling jig in order to assemble a head array with high accuracy. The positioning of this method is a pin alignment method in which the other side is a hole alignment with the assembly jig side pin, but this method requires a tight gap between the pin diameter and hole diameter when performing high-accuracy alignment. However, in this case, there is a problem in operability such as galling during assembly.

  In Patent Document 5, a taper-shaped adjusting screw is used for adjusting the longitudinal direction of the head array and adjusting the rotational direction, and does not press the head against the positioning pins.

  An object of the present invention is to solve the drawbacks of the prior art and to secure a highly accurate nozzle arrangement, a droplet discharge head positioning mechanism, a droplet discharge device, an image forming apparatus, a droplet discharge head positioning method, and It is to provide an exchange method.

In order to achieve the above object, the first means of the present invention is as follows:
Positioning of a droplet discharge head having a nozzle for discharging a droplet, and having a first side surface and a reference surface for defining the position of the nozzle on a second side surface orthogonal to the first side surface Mechanism,
A head mounting member such as a base frame to be described later, for example, to fix the liquid droplet ejection head positioned on the head mounting surface by providing an abutting portion that abuts the reference surface of the liquid droplet ejection head;
A head pressing-sliding jig that presses the reference surface of the droplet discharge head to the abutting portion side of the head mounting member such as a positioning pin described later,
The head pressing-sliding jig has a conical portion that gradually decreases in diameter toward the head mounting surface side in a state of standing on the head mounting surface of the head mounting member,
By screwing the head pressing-sliding jig toward the head mounting surface side, the tapered peripheral surface of the conical portion is brought into contact with a part of the droplet discharge head, and the head pressing-sliding jig is further screwed. The droplet discharge head is pressed and slid to the abutting portion side of the head mounting member for positioning, and a droplet is ejected between the cone portion of the head pressing-sliding jig and the abutting portion of the head mounting member. The liquid droplet ejection head is fixed to the head mounting member in a state where the head is sandwiched.

According to a second means of the present invention, in the first means,
A positioning hole is formed at a position of the head attachment member where the head pressing-sliding jig is installed, and the head pressing-sliding jig is detachably installed in the positioning hole. It is characterized by.

A third means of the present invention is the first or second means,
The head pressing-a pressure receiving member is detachably mounted on the liquid droplet discharging head at a portion of the liquid droplet discharging head that comes into contact with the conical portion of the slide jig, and the head pressing- The droplet discharge head is pressed and slid by a slide jig.

According to a fourth means of the present invention, in the first means,
A first reference surface is provided on a first side surface of the droplet discharge head, and a second reference surface and a third reference surface are provided on the second side surface at a predetermined interval;
A first abutment portion, a second abutment portion, and a third abutment portion that respectively abut the first reference surface, the second side surface, and the third reference surface on the head mounting member are provided. ,
The head pressing-sliding jig includes a shaft body having the conical portion in the middle of the axial direction, and the shaft body is installed at a position facing the first abutting portion via the droplet discharge head. A first shaft body, a second shaft body installed at a position facing the second abutting portion via the droplet discharge head, and the third shaft body via the droplet discharge head. Consists of a third shaft body installed at a position facing the abutting part,
By screwing the first shaft body, the second shaft body, and the third shaft body toward the head mounting surface side, the droplet discharge head is moved by the conical portion of each shaft body. It is characterized by being pressed and slid toward the contact portion, the second contact portion, and the third contact portion.

According to a fifth means of the present invention, in the fourth means,
A first positioning hole is opposed to the second abutting portion via the droplet ejection head at a position facing the first abutting portion via the droplet ejection head of the head mounting member. A second positioning hole is provided at a position, and a third positioning hole is provided at a position facing the third abutting portion via the droplet discharge head,
The head pressing-sliding jig includes a member holding frame having a holding portion that rotatably holds the first shaft body, the second shaft body, and the third shaft body at predetermined positions, respectively.
A shaft portion that is inserted through each positioning hole formed in each of the head mounting members is provided at the lower portion by the conical portion of each shaft body,
A screw part that is screwed into the screw hole of the holding part is provided at the upper part by the conical part of each shaft body,
A member holding frame holding the first shaft body, the second shaft body, and the third shaft body is detachably mounted on the head mounting member.

A sixth means of the present invention is the fourth means,
A first positioning screw hole is provided at a position facing the first abutting portion via the droplet discharge head of the head mounting member, and is opposed to the second abutting portion via the droplet ejection head. A second positioning screw hole is provided at a position where the third positioning screw hole is provided, and a third positioning screw hole is provided at a position facing the third abutting portion via the droplet discharge head,
A screw portion is provided at a lower portion by the conical portion of each shaft body, and each shaft body is detachably mounted in the positioning screw hole.

A seventh means of the present invention is the fourth to sixth means,
An operation portion for screwing the shaft body is provided at the head of the shaft body.

The eighth means of the present invention is the fourth to sixth means,
The angle between the axis of the shaft and the tapered peripheral surface of the conical portion is θt, the contact point between the upper end of the positioning pin and the droplet discharge head is P, and the pressing point of the droplet discharge head by the conical portion is Q When an angle between a line passing through the contact point P and a horizontal line with respect to the head mounting surface and a straight line connecting the contact point P and the pressing point Q is θh,
The relationship between the angle θt and the angle θh is such that θh <θt.

A ninth means of the present invention is the fourth to sixth means,
The contact point between the upper end of the positioning pin and the droplet discharge head is P, the pressing point of the droplet discharge head by the conical portion is Q, the vertical distance from the head mounting surface to the contact point P is L, the head When the vertical distance from the mounting surface to the pressing point Q is Lt,
The distance L and the distance Lt are configured such that L> Lt.

A tenth means of the present invention is a droplet discharge device,
The droplet discharge head is positioned and solidified on the head mounting member by using the droplet discharge head positioning mechanism of the first to ninth means.

An eleventh means of the present invention is an image forming apparatus,
The droplet discharge head is positioned and fixed to the head mounting member using the droplet discharge head positioning mechanism of the first to ninth means.

The twelfth means of the present invention is the eleventh means,
A plurality of droplet discharge heads are arranged in the recording paper conveyance direction to secure a printing area for one line.

A thirteenth means of the present invention is a method for positioning a droplet discharge head,
A droplet discharge head having a nozzle for discharging a droplet, and provided with a first side surface and a reference surface for defining the position of the nozzle on a second side surface orthogonal to the first side surface; A droplet discharge head mounting step of mounting on a head mounting surface of a head mounting member provided with an abutting portion that abuts a reference surface of the droplet discharge head;
A head pressing-sliding jig having a conical portion whose diameter gradually decreases toward the head mounting surface in a state of standing on the head mounting surface. A head pressing-sliding jig installation step standing on the side facing the part,
By screwing the head pressing-sliding jig toward the head mounting surface side, the tapered peripheral surface of the conical portion is brought into contact with a part of the droplet discharge head, and the head pressing-sliding jig is further screwed. A head positioning step for positioning the liquid droplet ejection head by pressing and sliding on the abutting portion side of the head mounting member;
A head fixing step of fixing the droplet discharge head to the head mounting member in a state where the droplet discharge head is sandwiched between the conical portion of the head pressing-sliding jig and the abutting portion of the head mounting member;
A head pressing-sliding jig removing step of removing the head pressing-sliding jig from the head mounting member is provided.

A fourteenth means of the present invention is a method for replacing a droplet discharge head,
A head removing step of removing the droplet discharge head to be replaced from the head mounting member;
A new droplet discharge head having a nozzle for discharging droplets and provided with a reference surface for defining the position of the nozzle on a first side surface and a second side surface orthogonal to the first side surface A droplet discharge head mounting step of mounting on the head mounting surface of the head mounting member provided with an abutting portion that abuts the reference surface of the droplet discharge head,
A head pressing-sliding jig having a conical portion whose diameter gradually decreases toward the head mounting surface in a state of standing on the head mounting surface. A head pressing-sliding jig installation step standing on the side facing the part,
By screwing the head pressing-sliding jig toward the head mounting surface side, the tapered peripheral surface of the conical portion is brought into contact with a part of the droplet discharge head, and the head pressing-sliding jig is further screwed. A head positioning step for positioning the liquid droplet ejection head by pressing and sliding on the abutting portion side of the head mounting member;
A head fixing step of fixing the droplet discharge head to the head mounting member in a state where the droplet discharge head is sandwiched between the conical portion of the head pressing-sliding jig and the abutting portion of the head mounting member;
A head pressing-sliding jig removing step of removing the head pressing-sliding jig from the head mounting member is provided.

  The present invention is configured as described above, and provides a droplet discharge head positioning mechanism, a droplet discharge device, an image forming apparatus, a droplet discharge head positioning method, and a replacement method that enable highly accurate nozzle arrangement. be able to.

FIG. 3 is an exploded perspective view for explaining a recording head positioning mechanism according to an embodiment of the invention. In embodiment of this invention, it is a figure which shows the initial setting state of a head press-slide jig in the front view which made a part the cross section when mounting a head press-slide jig in a head frame. In embodiment of this invention, it is a figure which shows the state in the middle of the positioning by a head press-slide jig in the front view which made a part the cross section when mounting a head press-slide jig in a head frame. In the embodiment of the present invention, it is a diagram for explaining the positional relationship between the conical portion of the taper member, the pressure receiving member of the recording head, and the height of the positioning pin with respect to the head frame. In another embodiment of this invention, it is the front view which made a part the cross section when mounting a head press-sliding jig in a head frame. FIG. 10 is a diagram for explaining a recording head replacement procedure in the embodiment of the present invention. It is a figure which shows the state which the recording head moved by tightening of a screw. FIG. 10 is a plan view of the ink-jet recording head unit according to the embodiment of the present invention when viewed from the Z direction in FIG. 9. 1 is a schematic configuration diagram of an inkjet printer according to an embodiment of the present invention.

Next, embodiments of the present invention will be described with reference to the drawings.
(Description of the entire printer)
FIG. 9 is a schematic configuration diagram of the ink jet printer according to the embodiment of the present invention.

  As shown in the figure, the ink jet printer includes a sheet feeding / conveying unit 2, one or a plurality of (one in this embodiment) image forming unit 3, and a sheet discharging / conveying unit along the recording sheet (web) 1 conveying direction. Units 4 are arranged and combined to form one ink jet printer.

  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 meandering correction mechanism, a static elimination mechanism, and a cleaning mechanism for the recording paper 1.

  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 at the bottom of the ink cassette 8. ) An ink jet recording head unit 9, a plurality of platen rollers 10 for conveying and guiding the recording paper 1 so as to pass through the vicinity of the lower surface of the ink jet recording head unit 9, an ink receiver 11 for ink trial hitting, An ink supply path (not shown) for supplying the ink in the ink cassette 8 to the ink-jet 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.

(Description of ink-jet recording head unit)
Next, the configuration of the ink jet recording head unit 9 will be described. FIG. 8 is a plan view of the ink-jet recording head unit 9 as viewed from the Z direction in FIG.
The ink-jet recording head unit 9 has a recording head 17 in which a plurality of nozzle holes 16 for ejecting ink are arranged in a flat base frame 15 in two rows in the conveyance direction of the recording paper 1 (see the arrow in the figure). As a whole, seven units are fixed by fixing screws 18a and 18b (see FIG. 1). The plurality of recording heads 17 are arranged in a staggered manner on the base frame 15.

  The recording head 17 has three reference surfaces 19a, 19b, and 19c provided thereon, the main scanning direction (direction orthogonal to the conveyance direction of the recording paper 1) X of the recording head 17 on the base frame 15, and The position in the sub-scanning direction (conveying direction of the recording paper 1) Y is determined.

  In this embodiment, the ink-jet recording head unit 9 includes four types of ink-jet recording head units 9a for four colors of different colors, for example, yellow (Y), magenta (M), cyan (C), and black (K). 9b, 9c, 9d are arranged along the conveyance direction of the recording paper 1, and are fixed to a frame (not shown) with screws. The recording heads 17 can be further arranged in the main scanning direction X according to the width size of the recording paper 1.

(Description of head positioning mechanism)
The ink-jet recording head unit 9 needs to incorporate the recording head 17 on the base frame 15 with high positional accuracy, and in particular, the arrangement accuracy in the main scanning direction (direction perpendicular to the conveyance direction of the recording paper 1) X is high. In a bad case, the pitch interval of the nozzle holes 16 is shifted between the adjacent recording heads 17, streaks are generated as a printing result, and the printing quality is deteriorated.

FIG. 1 is an exploded perspective view for explaining a recording head positioning mechanism according to an embodiment of the present invention.
As shown in FIG. 1, the recording head 17 in which a plurality of nozzle holes 16 for ejecting ink droplets are arranged in line has three reference surfaces 19a, 19b, and 19c on the end surfaces (side surfaces). One in Y (reference surface 19a) and two in the main scanning direction X (reference surfaces 19b and 19c) perpendicular to the Y are provided vertically. The reference surfaces 19a, 19b, and 19c are formed with high accuracy while observing the position of the nozzle hole 16 with an optical microscope or the like, and serve as a reference surface for defining the position of the nozzle hole 16 on the base frame 15. ing.

  The base frame 15 has positioning pins 25a, 25b, and 25c for determining the position of the recording head 17 at one location in the sub-scanning direction Y (positioning pins 25a) so as to correspond to the reference surfaces 19a, 19b, and 19c. In addition, two positions (positioning pins 25b and 25c) in the main scanning direction X perpendicular to the vertical direction are vertically provided with respect to the head mounting surface 32 which is the upper surface of the base frame 15.

  In FIG. 1, the shape and positional relationship of the reference surfaces 19 a, 19 b, 19 c and the positioning pins 25 a, 25 b, 25 c are clearly shown, so that the arrangement shown in FIG.

  The recording head 17 has screws 18a in a state in which the alignment positions of the nozzle holes 16 are secured by abutting the reference surfaces 19a, 19b, 19c provided on the recording head 17 against the positioning pins 25a, 25b, 25c of the base frame 15. , 18b to be fixed to the base frame 15. As described above, the recording head 17 is supported at three points during positioning.

  When the recording head 17 is brought into contact with the positioning pins 25a, 25b, and 25c, the head pressing / sliding jig 21 is used to prevent the recording head 17 from moving, and then the recording head 17 is moved to the base frame 15. Are fixed with screws 18a and 18b.

Next, a specific configuration of the head positioning mechanism will be described with reference to FIGS.
As shown in FIG. 1, the head pressing / sliding jig 21 includes three taper members 22a, 22b, and 22c, and a member holding frame 23 having a substantially U-shaped planar shape in which the taper members 22 are rotatably suspended. Has been.

For example, as shown in FIG. 3, the taper member 22 abuts against the recording head 17 and moves the recording head 17 in the horizontal direction on the head mounting surface 32 of the base frame 15, and a lower part of the conical portion 26. A shaft portion 27 for determining the position of the taper member 22, a screw portion 28 for moving the taper member 22 in the vertical direction provided on an upper portion of the conical portion 26, and an upper portion of the screw portion 28. It is comprised by the integral from the groove-shaped or + -shaped operation part 29 which is provided in this and rotates the taper member 22 with a driver etc. FIG.
The diameter of the conical portion 26 gradually decreases toward the lower side, and a tapered tapered peripheral surface 26a is formed on the outer periphery.

  As shown in FIGS. 1 to 3, a taper member holding portion 34 projects from the inside of the member holding frame 23, and a screw portion 28 of the taper member 22 is screwed into a screw 34 a of the taper member holding portion 34. Has been. Accordingly, the three taper members 22a, 22b, and 22c are respectively held at predetermined positions by the member holding frame 23 and are handled as one jig.

  As shown in FIG. 1, the head frame 15 is provided with straight positioning holes 30a, 30b, 30c through which the shaft portions 28 of the taper members 22a, 22b, 22c are inserted. The positioning hole 30a is provided at a position corresponding to the positioning pin 25a, the positioning hole 30b is provided with the positioning pin 25b, and the positioning hole 30c is provided with the positioning pin 25c.

  As shown in FIGS. 2 and 3, a step portion 33 is formed at a corner portion of the recording head 17 facing the taper member 22, and the step portion 33 is a component when the recording head 17 is positioned. In order to prevent the wear, a pressure receiving member 31 made of a small diameter cylindrical or spherical wear-resistant material (metal, hard synthetic resin, etc.) is placed.

(Recording head positioning procedure)
FIGS. 2 and 3 are front views, partly in section, when the head pressing-sliding jig 21 is mounted on the head frame 15, and FIG. 2 is a diagram showing an initial setting state of the head pressing-sliding jig 21. FIG. 3 is a diagram showing a state in the middle of positioning by the head pressing / sliding jig 21.

  First, as shown in FIG. 2, the recording head 17 is placed near the positioning pin 25 on the head frame 15, and the fixing screws 18a and 18b are loosely tightened so that the position of the recording head 17 can be adjusted. Keep it.

  The lower end of the shaft portion 27 of each taper member 22a, 22b, 22c held by the member holding frame 23 is inserted into each positioning hole 30a, 30b, 30c formed in the head frame 15, and each taper member 22a, 22b. 22c are held vertically, and in this state, the member holding frame 23 is fixed to the head frame 15 with screws 42a, 24b.

  The same state as this is shown in FIG. 6, and the recording head 17 is arranged inside the member holding frame 23 whose planar shape is substantially U-shaped. The taper member 22a is positioned with the positioning pin 25a via the recording head 17 (reference surface 19a), the taper member 22b is positioned with the positioning pin 25b via the recording head 17 (reference surface 19b), and the taper member 22c is the recording head. It faces the positioning pin 25c through 17 (reference surface 19c).

  Further, the pressure receiving member 31 is placed and set on the step portion 33 provided in the recording head 17. The pressure receiving member 31 protrudes slightly toward the taper member 22 from the side surface of the recording head 17, and the recording head 17 is always pressed by the taper member 22 through the wear-resistant pressure receiving member 31. Yes.

  By rotating the taper member 22 in this state, the taper member 22 gradually falls downward, the taper circumferential surface 26a of the conical portion 26 abuts against the pressure receiving member 31, and further rotating the taper member 22 causes the pressure receiving member to rotate. A pressing force (load) acts on the member 31 and the recording head 17 starts to slide in the horizontal direction along the head mounting surface 32 of the head frame 15.

  The taper member 22 continues to rotate, and when the recording head 17 (reference surface 19) hits the positioning pin 25, the position of the recording head 17 is determined and the position is held. FIG. 3 shows a state in which the recording head 17 (reference surface 19) contacts the positioning pin 25 and is positioned. This positioning is performed by the cooperation of the respective taper members 22a, 22b, and 22c and the positioning pins 25a, 25b, and 25c, and the recording head 17 is secured at appropriate positions in the main scanning direction X and the sub-scanning direction Y.

  The same state as this is shown in FIG. 6, in which the pressing directions by the taper members 22a, 22b, and 22c are indicated by arrows, and each point toward the positioning pins 25a, 25b, and 25c.

  Here, the positional relationship of the height of the conical portion 26 of the taper member 22, the pressure receiving member 31 of the recording head 17, and the positioning pin 25 with respect to the head frame 15 will be described with reference to FIG.

  As shown in FIG. 4, the angle formed by the axis of the taper member 22 and the tapered peripheral surface 26a of the conical portion 26 is θt, the contact point between the upper end of the positioning pin 25 and the recording head 17 is P, and the pressure receiving member 31 and the cone When the contact point of the shape portion 26 (tapered peripheral surface 26a) (that is, the pressing point of the recording head 17 by the conical shape portion 26) is Q, a line that passes through the contact point P and is parallel to the head mounting surface 32 is shown. When the angle between the contact point P and the straight line connecting the contact point Q is θh, the relationship between the angle θt and the angle θh is set to a positional relationship (configuration) such that θh <θt.

  In this positional relationship, the load at which the conical portion 26 (tapered circumferential surface 26a) pushes the pressure receiving member 31 at the position of the contact point Q is in the direction F perpendicular to the taper 26a of the conical portion 26. The force is a load F2 in the direction in which the contact point P is pressed and a load F1 in a direction perpendicular to the downward direction in the figure with respect to the straight line connecting the contact point P and the contact point Q. Moment works in the direction with the load and direction of F1.

  Therefore, by adopting the configuration in which the above-described positional relationship is maintained, when the recording head 17 is pressed by the taper member 22, the moment around the contact point P acts on the head mounting surface side. The positional deviation caused by the phenomenon that the image is lifted is resolved, and the recording head 17 can be positioned with high accuracy.

FIG. 5 is a diagram for explaining another embodiment of the present invention.
In this embodiment, as in FIG. 4, the contact point between the upper end of the positioning pin 25 and the recording head 17 is P, and the contact point between the pressure receiving member 31 and the conical portion 26 (taper 26a) (ie, by the conical portion 26). Let Q be the pressing point of the recording head 17. Further, if the vertical distance from the head mounting surface 32 to the contact point P is L and the vertical distance from the head mounting surface 32 to the contact point Q is Lt, the relationship between the distance L and the distance Lt is L> Lt. The positional relationship is as follows.

  In this positional relationship, the load at which the conical portion 26 (tapered circumferential surface 26a) pushes the pressure receiving member 31 at the position of the contact point Q is in the direction F perpendicular to the tapered circumferential surface 26a of the conical portion 26, and the load F Is a load F2 in the direction in which the contact point P is pressed and a load F1 in the direction perpendicular to the downward direction in the figure with respect to the straight line connecting the contact point P and the contact point Q. A moment acts in the direction with the load and direction of F1 around P.

  Therefore, by adopting the configuration in which the above positional relationship is maintained, the moment around the contact point P acts on the head mounting surface 32 side when the recording head 17 is pressed by the taper member 22 as in FIG. The positional deviation caused by the phenomenon that the recording head 17 is lifted from 32 can be solved, and the recording head 17 can be positioned with high accuracy.

  When the recording head 17 is sandwiched and positioned between the positioning pins 25a, 25b, and 25c and the taper members 22a, 22b, and 22c in this way, the fixing screws 18a and 18b are tightened, and the recording head 17 is moved to the head of the base frame 15. Fix on the mounting surface 32. After fixing the recording head 17, the member holding frame 23 holding the taper members 22 a, 22 b, and 22 c is removed from the base frame 15, and the press receiving member 31 is removed from the recording head 17, thereby positioning the recording head 17. The work is finished.

  The removed head pressing-sliding jig 21 and the pressure receiving member 31 are used for positioning of the next recording head 17.

  What is necessary in the two embodiments is that a moment in the clockwise direction acts on the recording head 17 toward the paper surface in FIGS. 4 and 5 so that the recording head 17 does not float around the point P (see FIG. 4). The angle may be defined as a means for satisfying it, or may be defined by a distance.

  In the case of FIG. 4, by reducing the height of the positioning pin 25 as much as possible, an error in the abutting position due to the positioning pin 25 tilting with respect to the base frame 15 is reduced, and high positioning accuracy can be obtained. On the other hand, in the case of FIG. 5, since the angle θh can be made relatively gentle, the force for sliding the recording head 17 in the lateral direction is small, and the positioning operability of the recording head 17 is good.

(Recording head replacement procedure)
Next, a procedure for replacing the recording head 17 will be described with reference to FIG. This figure is a plan view showing a state in which a plurality of recording heads 17 are arranged on the base frame 15.

  If there is a recording head 17 that has failed due to some inconvenience, it is identified, and the fixing screws 18 a and 18 b of the recording head 17 are loosened and removed from the base frame 15.

  Then, a new recording head 17 is temporarily fixed to the base frame 15 with fixing screws 18a and 18b. Next, the head pressing-sliding jig 21 is placed near the temporarily fixed new recording head 17, and the lower end portions of the taper members 22 a, 22 b, 22 c held by the head pressing-sliding jig 21. Is inserted into the positioning holes 30a, 30b, 30c formed in the base frame 15, the head pressing-sliding jig 21 is fixed on the base frame 15 with fixing screws 24a, 24b, and the step of the new recording head 17 is fixed. The pressure receiving member 31 is set on the portion 33. This state is the same as in FIG.

  Next, the taper members 22a, 22b, and 22c are rotated using a screwdriver or the like, and are rotated to a point where they do not rotate. As a result, the new recording head 17 hits the three positioning pins 25a, 25b, and 25c, and the positioning in the main scanning direction X and the sub-scanning direction Y is simultaneously performed. This state is the same as in FIG.

  The rotation order of the three taper members 22a, 22b, and 22c is not particularly defined. Further, if the screw torque is managed as the rotation end state of the taper member 22, it is possible to prevent the taper peripheral surface 26 a of the taper member 22 and the surface damage of the press receiving member 31.

  When the positioning of the recording head 17 is completed in this way, the fixing screws 18a and 18b are finally tightened, the head pressing-sliding jig 21 is removed from the base frame 15, and the pressure receiving member 31 is detached from the recording head 17 to perform recording. The replacement operation of the head 17 is finished.

  A problem when replacing the recording head 17 is the position reproducibility of the nozzle holes 16 in the recording head 17. In the case of a line-type head, the arrangement accuracy between the recording heads is assembled with high accuracy of about several μm to several tens of μm, sufficiently pressing the positioning pins 25a, 25b, and 25c, and screw tightening It is necessary to maintain that state later. In particular, in the case of fixing with screws, the recording head 17 moves as shown by a chain line in FIG. 7 by tightening the screws, so that there is a problem that the position reproducibility of the nozzle holes 16 cannot be ensured.

  In addition, the work time and the difficulty of work when the recording head 17 is exchanged have a problem that it affects an increase in printer downtime and an increase in CPP.

  With respect to these problems, in the present invention, when the recording head 17 is fixed with the screw 18, the entire recording head 17 is clamped (temporarily fixed) by the taper members 22a, 22b, 22c and the positioning pins 25a, 25b, 25c. Accordingly, the position reproducibility of the nozzle hole 16 can be ensured without moving as shown by the chain line in FIG. Further, since the recording head 17 can be easily replaced, there is no increase in printer downtime or CPP.

  As described above, according to the present invention, since the recording head can be replaced with high accuracy by a simple procedure, the recording head can be replaced not only by a service person who maintains and manages the printer but also by a general operator.

  In the above-described embodiment, the positioning pins 25a, 25b, and 25c are provided to abut the reference surfaces 19a, 19b, and 19c of the recording head 17, but the present invention is not limited to this. An abutting portion having another shape such as a stepped or projecting abutting portion provided integrally may be used.

  In the embodiment, for example, as shown in FIG. 2, the shaft portion 27 of the taper member 22 is inserted into a straight positioning hole 30 provided in the base frame 15, while the screw portion 28 of the taper member 22 is held by the taper member. Although the structure in which the screw hole 34a of the portion 34 is screwed is shown, the present invention is not limited to this. For example, the screw hole portion is formed on the positioning hole 30 of the base frame 15 and the shaft portion 27 of the taper member 22, respectively. It is also possible to screw the taper member 22 into the base frame 15. At this time, the upper portion of the conical portion 26 of the taper member 22 may be a straight shaft portion, and the shaft portion may be inserted into a through hole provided in the taper member holding portion 34.

  In the above-described embodiment, the indirect mounting structure in which the three taper members 22a, 22b, and 22c are held on the member holding frame 23 and the member holding frame 23 is attached to the base frame 15 has been described, but the present invention is limited to this. It is also possible to attach the three taper members 22 a, 22 b, 22 c directly to the base frame 15 without using the member holding frame 23. At this time, as described above, it is possible to provide a structure in which screw portions are provided in the positioning hole 30 of the base frame 15 and the shaft portion 27 of the taper member 22 and the taper member 22 is screwed into the base frame 15.

  In the 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, and for example, a three-dimensional modeling apparatus that manufactures a three-dimensional modeled object The present invention can also be applied to other technical fields.

1: Recording paper (web),
2: Paper feed unit,
3: Image creation unit,
4: Discharge transport unit,
8: Ink cassette,
9, 9a to 9d: Inkjet head unit,
15: Base frame,
16: Nozzle hole,
17: recording head,
18a, 18b: fixing screws,
19a, 19b, 19c: reference plane,
20a, 20b: fixing screws,
21: Head pressing-sliding jig,
22a, 22b, 22c: taper member,
23: member holding frame,
24: fixing screw,
25a, 25b, 25c: positioning pins,
26: conical part,
26a: taper circumferential surface,
27: shaft part,
28: Screw part,
29: Operation unit,
30a, 30b, 30c: positioning holes,
31: a pressure receiving member,
32: Head mounting surface
33: Stepped portion,
34: taper member holding member,
34a: screw hole,
X: main scanning direction,
Y: Sub-scanning direction.

JP-A-10-951144 JP 2004-322606 A JP 2008-296518 A Japanese Patent No. 3894000 JP 2007-76176 A

Claims (14)

Positioning of a droplet discharge head having a nozzle for discharging a droplet, and having a first side surface and a reference surface for defining the position of the nozzle on a second side surface orthogonal to the first side surface Mechanism,
A head mounting member for fixing the liquid droplet ejection head positioned on the head mounting surface, each provided with an abutting portion that abuts the reference surface of the liquid droplet ejection head;
A head pressing-sliding jig that presses the reference surface of the droplet discharge head to the abutting portion side of the head mounting member;
The head pressing-sliding jig has a conical portion that gradually decreases in diameter toward the head mounting surface side in a state of standing on the head mounting surface of the head mounting member,
By screwing the head pressing-sliding jig toward the head mounting surface side, the tapered peripheral surface of the conical portion is brought into contact with a part of the droplet discharge head, and the head pressing-sliding jig is further screwed. The droplet discharge head is pressed and slid to the abutting portion side of the head mounting member for positioning, and a droplet is ejected between the cone portion of the head pressing-sliding jig and the abutting portion of the head mounting member. A droplet discharge head positioning mechanism characterized in that the droplet discharge head is fixed to a head mounting member while the head is sandwiched. In the positioning mechanism of the droplet discharge head according to claim 1,
A positioning hole is formed at a position of the head attachment member where the head pressing-sliding jig is installed, and the head pressing-sliding jig is detachably installed in the positioning hole. A positioning mechanism for a droplet discharge head. In the positioning mechanism of the droplet discharge head according to claim 1 or 2,
The head pressing-a pressure receiving member is detachably mounted on the liquid droplet discharging head at a portion of the liquid droplet discharging head that comes into contact with the conical portion of the slide jig, and the head pressing- A droplet discharge head positioning mechanism characterized in that the droplet discharge head is pressed and slid by a slide jig. In the positioning mechanism of the droplet discharge head according to claim 1,
A first reference surface is provided on a first side surface of the droplet discharge head, and a second reference surface and a third reference surface are provided on the second side surface at a predetermined interval;
A first abutment portion, a second abutment portion, and a third abutment portion that respectively abut the first reference surface, the second side surface, and the third reference surface on the head mounting member are provided. ,
The head pressing-sliding jig includes a shaft body having the conical portion in the middle of the axial direction, and the shaft body is installed at a position facing the first abutting portion via the droplet discharge head. A first shaft body, a second shaft body installed at a position facing the second abutting portion via the droplet discharge head, and the third shaft body via the droplet discharge head. Consists of a third shaft body installed at a position facing the abutting part,
By screwing the first shaft body, the second shaft body, and the third shaft body toward the head mounting surface side, the droplet discharge head is moved by the conical portion of each shaft body. A positioning mechanism for a droplet discharge head, wherein the positioning is performed by pressing and sliding toward the abutment portion, the second abutment portion, and the third abutment portion. In the positioning mechanism of the droplet discharge head according to claim 4,
A first positioning hole is opposed to the second abutting portion via the droplet ejection head at a position facing the first abutting portion via the droplet ejection head of the head mounting member. A second positioning hole is provided at a position, and a third positioning hole is provided at a position facing the third abutting portion via the droplet discharge head,
The head pressing-sliding jig includes a member holding frame having a holding portion that rotatably holds the first shaft body, the second shaft body, and the third shaft body at predetermined positions, respectively.
A shaft portion that is inserted through each positioning hole formed in each of the head mounting members is provided at the lower portion by the conical portion of each shaft body,
A screw part that is screwed into the screw hole of the holding part is provided at the upper part by the conical part of each shaft body,
A droplet discharge head having a structure in which a member holding frame holding the first shaft body, the second shaft body, and the third shaft body is detachably mounted on the head mounting member. Positioning mechanism. In the positioning mechanism of the droplet discharge head according to claim 4,
A first positioning screw hole is provided at a position facing the first abutting portion via the droplet discharge head of the head mounting member, and is opposed to the second abutting portion via the droplet ejection head. A second positioning screw hole is provided at a position where the third positioning screw hole is provided, and a third positioning screw hole is provided at a position facing the third abutting portion via the droplet discharge head,
A positioning mechanism for a droplet discharge head, wherein a screw portion is provided at a lower portion by a conical portion of each shaft body, and each shaft body is detachably attached to the positioning screw hole. In the positioning mechanism of the droplet discharge head according to any one of claims 4 to 6,
A positioning mechanism for a droplet discharge head, wherein an operation portion for screwing the shaft body is provided at a head of the shaft body. In the positioning mechanism of the droplet discharge head according to any one of claims 4 to 6,
The angle between the axis of the shaft and the tapered peripheral surface of the conical portion is θt, the contact point between the upper end of the positioning pin and the droplet discharge head is P, and the pressing point of the droplet discharge head by the conical portion is Q When an angle between a line passing through the contact point P and a horizontal line with respect to the head mounting surface and a straight line connecting the contact point P and the pressing point Q is θh,
A droplet discharge head positioning mechanism, wherein the relationship between the angle θt and the angle θh is such that θh <θt. In the positioning mechanism of the droplet discharge head according to any one of claims 4 to 6,
The contact point between the upper end of the positioning pin and the droplet discharge head is P, the pressing point of the droplet discharge head by the conical portion is Q, the vertical distance from the head mounting surface to the contact point P is L, the head When the vertical distance from the mounting surface to the pressing point Q is Lt,
A droplet discharge head positioning mechanism, wherein the relationship between the distance L and the distance Lt is L> Lt.   10. A liquid droplet ejection apparatus, wherein the liquid droplet ejection head is positioned and solidified on the head mounting member by using the liquid droplet ejection head positioning mechanism according to claim 1.   An image forming apparatus, wherein the droplet discharge head is positioned and fixed to the head mounting member using the droplet discharge head positioning mechanism according to claim 1.   12. The image forming apparatus according to claim 11, wherein a plurality of the liquid droplet ejection heads are arranged in a recording sheet conveyance direction to secure a printing area for one line. A droplet discharge head having a nozzle for discharging a droplet, and provided with a first side surface and a reference surface for defining the position of the nozzle on a second side surface orthogonal to the first side surface; A droplet discharge head mounting step of mounting on a head mounting surface of a head mounting member provided with an abutting portion that abuts a reference surface of the droplet discharge head;
A head pressing-sliding jig having a conical portion whose diameter gradually decreases toward the head mounting surface in a state of standing on the head mounting surface. A head pressing-sliding jig installation step standing on the side facing the part,
By screwing the head pressing-sliding jig toward the head mounting surface side, the tapered peripheral surface of the conical portion is brought into contact with a part of the droplet discharge head, and the head pressing-sliding jig is further screwed. A head positioning step for positioning the liquid droplet ejection head by pressing and sliding on the abutting portion side of the head mounting member;
A head fixing step of fixing the droplet discharge head to the head mounting member in a state where the droplet discharge head is sandwiched between the conical portion of the head pressing-sliding jig and the abutting portion of the head mounting member;
A method of positioning a droplet discharge head, comprising: a head pressing / sliding jig removing step of removing the head pressing / sliding jig from the head mounting member. A head removing step of removing the droplet discharge head to be replaced from the head mounting member;
A new droplet discharge head having a nozzle for discharging droplets and provided with a reference surface for defining the position of the nozzle on a first side surface and a second side surface orthogonal to the first side surface A droplet discharge head mounting step of mounting on the head mounting surface of the head mounting member provided with an abutting portion that abuts the reference surface of the droplet discharge head,
A head pressing-sliding jig having a conical portion whose diameter gradually decreases toward the head mounting surface in a state of standing on the head mounting surface. A head pressing-sliding jig installation step standing on the side facing the part,
By screwing the head pressing-sliding jig toward the head mounting surface side, the tapered peripheral surface of the conical portion is brought into contact with a part of the droplet discharge head, and the head pressing-sliding jig is further screwed. A head positioning step for positioning the liquid droplet ejection head by pressing and sliding on the abutting portion side of the head mounting member;
A head fixing step of fixing the droplet discharge head to the head mounting member in a state where the droplet discharge head is sandwiched between the conical portion of the head pressing-sliding jig and the abutting portion of the head mounting member;
A method of replacing a droplet discharge head, comprising: a head pressing / sliding jig removing step of removing the head pressing / sliding jig from the head mounting member.

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