JP5549114B2 - Head unit assembling apparatus and head unit assembling method - Google Patents

Description

  The present invention relates to a head unit assembling apparatus and a head unit assembling method.

  2. Description of the Related Art Conventionally, as an inkjet recording apparatus that records a desired image by ejecting ink droplets from an inkjet head, a line head type in which a plurality of inkjet heads are arranged in a head unit is known for shortening the recording time. ing.

  In this line head type ink jet recording apparatus, the positional relationship between the ink jet heads arranged on the base plate of the head unit greatly affects the image quality. In particular, in industrial applications where a fine wiring pattern or the like is formed, high ink droplet ejection accuracy is required, so that each inkjet head needs to be positioned with high accuracy with respect to the base plate.

  Therefore, the camera includes an image recognition camera for the inkjet head and the carriage (base plate), and an arm for holding the inkjet head by engaging a pin provided at the tip with the hole of the inkjet head. Based on the results, there has been proposed a head unit assembling apparatus capable of accurately positioning the ink jet head with respect to the base plate by rotating the base end of the arm to perform the positioning operation of the ink jet head (for example, patents). Reference 1).

JP 2003-127392 A

  However, in the apparatus described in Patent Document 1, since the base end of the arm is rotated when positioning the inkjet head, the center of rotation is a position separated from the inkjet head that is the positioning target. As a result, even if, for example, it is desired to rotate the inkjet head only at that position, translational movement must be accompanied, which complicates the positioning operation and requires a long time. In addition, the ink jet head cannot be rotated precisely, and positioning with higher accuracy becomes difficult.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a head unit assembling apparatus and a head unit assembling method capable of positioning an inkjet head with high accuracy in a short time as compared with the prior art.

In order to solve the above-mentioned problem, the invention according to claim 1
A head unit assembly device for positioning and fixing an inkjet head to a base plate,
Recognition means for recognizing a plurality of reference portions of the inkjet head and a plurality of reference marks of the base plate;
Translational movement means for relatively translating the inkjet head and the base plate;
A head rotating means for rotating the inkjet head around a substantially center of the inkjet head;
Fixing means for fixing the inkjet head to the base plate;
Based on the recognition result by the recognizing means, the translation moving means and the head rotating means are controlled to position the inkjet head on the base plate, and the fixing means is controlled to position the positioned inkjet head. Control means for fixing to the base plate;
With
The head rotating means is provided with a gripping portion for gripping a pair of diagonal portions of the inkjet head formed in a square plate shape ,
The fixing means is characterized in that among the corner portions of the inkjet head, another set of diagonal portions that are not gripped by the grip portion are screwed to the base plate .

The invention according to claim 2 is the head unit assembling apparatus according to claim 1,
The inkjet head has at least two nozzles that eject ink droplets and have a midpoint positioned substantially in the center of the inkjet head.
The plurality of reference portions are the two nozzles.

The invention according to claim 3 is the head unit assembly apparatus according to claim 1,
The inkjet head has two fiducial marks whose midpoint is located approximately at the center of the inkjet head,
The plurality of reference portions are the two reference marks.

Invention of Claim 4 is a head unit assembly apparatus as described in any one of Claims 1-3 ,
Before being positioned on the base plate, the inkjet head is temporarily fixed to such an extent that it can move relative to the base plate.

The invention described in claim 5
A head unit assembly method for positioning and fixing an inkjet head to a base plate,
Using the inkjet head having a plurality of reference parts,
Using the base plate having a plurality of reference marks,
Recognizing the plurality of reference portions and the plurality of reference marks;
Based on the recognition result in the recognition step, the inkjet head and the base plate are relatively translated, and the inkjet head is rotated by rotating the inkjet head around the substantially center of the inkjet head. A positioning step of positioning on the base plate;
A fixing step of fixing the inkjet head to the base plate;
With
In the positioning step and the fixing step, a pair of diagonal portions of the inkjet head formed in a square plate shape is gripped ,
In the fixing step, among the corner portions of the inkjet head, another pair of diagonal portions that are not gripped are screwed to the base plate .

The invention according to claim 6 is the head unit assembly method according to claim 5 ,
As the inkjet head, one that has at least two nozzles that eject ink droplets and whose midpoint is located at the approximate center of the inkjet head is used.
The plurality of reference portions are the two nozzles.

The invention according to claim 7 is the head unit assembly method according to claim 5 ,
As the ink jet head, one having two reference marks whose midpoint is located at substantially the center of the ink jet head is used.
The plurality of reference portions are the two reference marks.

Invention of Claim 8 is a head unit assembly method as described in any one of Claims 5-7 ,
As the ink jet head, one that is temporarily fixed to the extent that it can move relative to the base plate is used before the positioning step.

  According to the present invention, since the inkjet head is rotated and positioned on the base plate around the substantially center of the inkjet head, that is, unlike the conventional case, the rotation center is not separated from the inkjet head to be positioned. The positioning operation is simplified as compared with the prior art, and positioning in a short time is possible. In addition, the ink-jet head can be rotated precisely, and highly accurate positioning can be performed. Therefore, the inkjet head can be positioned with high accuracy in a short time as compared with the prior art.

It is a perspective view of the head unit assembly apparatus concerning the present invention. It is a top view of a head unit. FIG. 3 is a top view of the recording head. It is a disassembled perspective view of a head rotation part and a clamper. It is a block diagram which shows the control structure of a head unit assembly apparatus. 3 is a flowchart of a head unit assembling method according to the present invention. (A) It is a figure which shows an example of the image recognized with the 1st camera and the 2nd camera, (b) It is a figure which shows another example. It is a figure which shows the other another example of the image recognized with the 1st camera and the 2nd camera.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a head unit assembling apparatus 1 according to the present invention, and FIG. 2 is a top view of a head unit 100 assembled by the head unit assembling apparatus 1.
As shown in FIG. 1, the head unit assembling apparatus 1 includes a base plate support unit 2, a camera holding unit 3, and a head position adjustment unit 4 disposed on a bottom plate 11. As will be described later, the head unit assembling apparatus 1 is an apparatus for assembling the head unit 100 by positioning and fixing a plurality of recording heads 102 to the base plate 101.

  The base plate support unit 2 includes a support bed 21 that fixes and supports the base plate 101 of the head unit 100. The support bed 21 includes an X-direction movement mechanism 22, a Y-direction movement mechanism 23, and a rotation mechanism 24 (see FIG. 5). The X-direction movement mechanism 22, the Y-direction movement mechanism 23, and the rotation mechanism 24 cause an arrow to move. Translational movement in the X direction (hereinafter referred to as the X direction) and the direction of the arrow Y orthogonal to the X direction (hereinafter referred to as the Y direction) is possible, and rotation in the horizontal plane (XY plane) is possible. It has become.

  The base plate 101 supported by the base plate support portion 2 is a substantially rectangular flat plate disposed so as to extend in the X direction. As shown in FIG. 2, two cross-shaped base plate reference marks 101a and 101a are formed at both ends of the base plate 101 in the X direction. The two base plate reference marks 101a and 101a are provided in a predetermined positional relationship with respect to the respective positions of the plurality of recording heads 102 fixed to the base plate 101.

  Further, before the head unit 100 is assembled, a plurality of recording heads 102 formed in a rectangular plate shape are temporarily fixed to the base plate 101 to such an extent that they can be moved relative to the base plate 101. . More specifically, the bar-shaped ink flow path members 103,... (See FIG. 4) fixed to the respective recording heads 102 are inserted into insertion holes (not shown) of the base plate 101, so that the ink flow path members 103,. The recording heads 102,... Can be moved relative to the base plate 101 within the range of the clearance from the insertion hole. The recording heads 102,... Are arranged on the upper surface of the base plate 101 in a plurality of rows in the X direction and in two rows in the Y direction so as to form a staggered arrangement.

FIG. 3 is a top view of the recording head 102.
As shown in this figure, the recording head 102 includes a nozzle holding plate 104 formed in a square plate shape, and a rectangular plate shape that is slightly smaller than the nozzle holding plate 104 on the upper surface of the nozzle holding plate 104. The nozzle plate 105 formed in the above is affixed. On the upper surface of the nozzle plate 105, a plurality of nozzles 106 for ejecting ink droplets are arranged in the X direction and arranged in two rows in the Y direction so as to be staggered.

  Further, at both ends in the X direction of the nozzle plate 105, two cross-shaped head reference marks 105a and 105a are formed so that the midpoint is located at the approximate center of the nozzle holding plate 104 (recording head 102). The two head reference marks 105a and 105a are separated from each other by a predetermined distance, and are provided so as to have a predetermined positional relationship with respect to the positions of the nozzles 106,.

  Of the description of the recording head 102 and the nozzle 106 described above, the direction-related items describe the direction of each part in a state where the recording head 102 is correctly positioned on the base plate 101.

  As shown in FIG. 1, the camera holding unit 3 is supported by a portal-type support member 31 fixed on the bottom plate 11 and is disposed above the base plate support unit 2. The camera holding unit 3 is provided with a first camera 32 and a second camera 33 capable of photographing the lower side in parallel in the X direction. When the first camera 32 and the second camera 33 position the recording heads 102,... On the base plate 101, the head reference marks 105a, 105a of each recording head 102 and the base plate reference marks 101a, 101a for image recognition. Each of the first camera 32 and the second camera 33 includes a focus adjustment mechanism 34 (see FIG. 5). Further, the second camera 33 is provided with a second camera moving mechanism 35 (see FIG. 5), and is configured to be movable in the X direction and the Y direction by the second camera moving mechanism 35.

  The head position adjustment unit 4 includes a support plate 42 that is cantilevered by a support base 41. The support plate 42 is supported by the support base 41 via a Z-direction moving mechanism 43 (see FIG. 5), and is configured to be movable in the Z direction (vertical direction) by the Z-direction moving mechanism 43. The distal end portion of the support plate 42 is located below the camera holding portion 3, and a through hole 42 a is formed in a portion located below the first camera 32 and the second camera 33. A laminated disk-like head rotating unit 44 is supported on the lower surface of the front end portion of the support plate 42 so as to be rotatable in the XY plane, and a clamper for holding the recording head 102 is disposed on the lower surface of the head rotating unit 44. 45 is arranged.

FIG. 4 is an exploded perspective view of the head rotating unit 44 and the clamper 45. In FIG. 4, for ease of explanation, the clamper 45 in a state where the recording head 102 is held is illustrated.
As shown in this figure, the clamper 45 is configured to grip a pair of diagonal portions of the recording head 102 (nozzle holding plate 104) toward the diagonal center of the recording head 102. The recording head 102 is fixed to the lower surface of the head rotating portion 44 so that the center of the recording head 102 substantially coincides with the rotation center of the head rotating portion 44. With such a structure, the head rotating unit 44 can rotate the recording head 102 around the approximate center of the recording head 102.

  A through hole 44a having the same inner diameter as the through hole 42a of the support plate 42 and concentrically communicating with the through hole 42a is formed at the center of the head rotating portion 44. Each of the through hole 42a and the through hole 44a has an inner diameter larger than the distance between the two head reference marks 105a and 105a. Therefore, the first camera 32 and the second camera 33 arranged above the through hole 42a of the support plate 42 are connected to the 2 on the recording head 102 held by the clamper 45 through the through hole 42a and the through hole 44a. The two head reference marks 105a and 105a can be photographed and recognized.

  The head position adjusting unit 4 is provided with a head fixing unit 5 (see FIG. 5) that fixes the recording head 102 to the base plate 101. The head fixing portion 5 is configured so that the corners of the four corners of the recording head 102 are screwed to the base plate 101 with respect to the recording head 102 positioned on the base plate 101.

Next, the control configuration of the head unit assembly apparatus 1 will be described with reference to FIG.
FIG. 5 is a block diagram showing a control configuration of the head unit assembling apparatus 1.
As shown in this figure, the head unit assembling apparatus 1 includes a control unit 10.

  The control unit 10 is connected to the X-direction movement mechanism 22, the Y-direction movement mechanism 23, and the rotation mechanism 24 of the base plate support unit 2, and translates the support bed 21 in the X-direction and the Y-direction, and in the XY plane. It is configured to be able to control the rotation at. The control unit 10 is connected to the first camera 32 and the second camera 33 of the camera holding unit 3, and is configured to control each focus adjustment mechanism 34 so that the respective focus adjustments can be made. The mechanism 35 is configured to control the movement of the second camera 33 in the X direction and the Y direction, and image information from the first camera 32 and the second camera 33 is input. ing.

  The control unit 10 is connected to the Z-direction moving mechanism 43 of the head position adjusting unit 4 so as to be able to control the movement of the support plate 42 in the Z direction, and is connected to the head rotating unit 44 to be connected to the head rotating unit. The rotation of 44 in the XY plane is controllable, and connected to the clamper 45 so that the gripping / release of the recording head 102 by the clamper 45 can be controlled. The control unit 10 is connected to the head fixing unit 5, and is configured to be able to control the head fixing unit 5 to fix the recording head 102 to the base plate 101.

  With the above configuration, when a head unit assembly command is input from a user via a control PC (not shown), the control unit 10 performs a predetermined control operation on each unit and assembles the head unit 100 as will be described later. It has become.

Next, a head unit assembling method for positioning and fixing the recording heads 102,... To the base plate 101 by the head unit assembling apparatus 1 will be described with reference to FIG.
FIG. 6 is a flowchart of the head unit assembling method.

  As shown in this figure, first, the base plate 101 is placed and fixed on the support bed 21 of the base plate support portion 2 (step S1). At this time, a plurality of recording heads 102,... Are temporarily fixed to the base plate 101 to the extent that they can be moved relative to the base plate 101. At this time, since the alignment of the base plate 101 with respect to the head unit assembling apparatus 1 has not yet been adjusted, the arrangement direction of the recording heads 102 in the base plate 101 is the moving direction (X Direction).

  When the user inputs a head unit assembly command to the control unit 10, the control unit 10 adjusts the focus of the first camera 32 and the second camera 33 (step S2). In this step, the control unit 10 adjusts the focus of the first camera 32 and the second camera 33 to the upper surface of the base plate 101.

  Next, the controller 10 recognizes images of the base plate reference marks 101a and 101a of the base plate 101 (step S3). In this step, the control unit 10 controls the X-direction moving mechanism 22 and the Y-direction moving mechanism 23 so that the base plate 101 fixed to the support bed 21 is positioned below the first camera 32 with the base plate reference mark 101a. Move until Then, the first camera 32 is made to recognize the base plate reference mark 101a, and its coordinate information is acquired. The control unit 10 sequentially executes these movement control and coordinate acquisition control for the two base plate reference marks 101a and 101a.

  Next, the controller 10 adjusts the alignment of the base plate 101 with respect to the head unit assembly apparatus 1 (step S4). In this step, the control unit 10 controls the rotation mechanism 24 based on the coordinate information of the two base plate reference marks 101a, 101a acquired in step S3, and in each row of the recording heads 102,. The base plate 101 is rotated so that the arrangement direction of the support plate 21 and the movement direction (X direction) of the support bed 21 coincide. In the present embodiment, the control unit 10 rotates the base plate 101 so that the two base plate reference marks 101a and 101a are aligned in the X direction. Then, the control unit 10 resets the coordinate system on the base plate 101 to that after alignment adjustment.

  Next, the control unit 10 adjusts the position of the second camera 33 (step S5). In this step, the control unit 10 controls the X direction moving mechanism 22 to move the base plate 101 in the X direction, and moves one base plate reference mark 101 a from below the first camera 32 to below the second camera 33. The recording head 102 is moved by the distance between the two head reference marks 105a and 105a. Then, the second camera moving mechanism 35 is controlled to move the second camera 33 in the X direction and the Y direction, and the second base plate reference mark 101a is moved until the second camera 33 can be recognized similarly to the first camera 32. The position of the camera 33 is finely adjusted. As a result, the first camera 32 and the second camera 33 are adjusted so that positions separated from each other in the X direction by the distance between the two head reference marks 105a and 105a can be recognized.

  Next, the control unit 10 adjusts the focus of the first camera 32 and the second camera 33 again (step S6). In this step, the control unit 10 adjusts the focus of the first camera 32 and the second camera 33 to the upper surface of the nozzle plate 105 of the recording head 102.

  Next, the control unit 10 positions the recording head 102 on the base plate 101 (step S7). In this step, the control unit 10 determines the recording head 102 to be positioned according to a preset positioning sequence, and then controls the X direction moving mechanism 22 and the Y direction moving mechanism 23 to be temporarily fixed to the base plate 101. The recording head 102 is moved to below the clamper 45. Then, by controlling the Z-direction moving mechanism 43 and moving the support plate 42 downward, the clamper 45 is lowered to a position where the recording head 102 can be gripped, and the clamper 45 is controlled to set one set of the recording head 102. Is held toward the center of the recording head 102 on the diagonal line.

  At this time, the recording head 102 and the base plate 101 are roughly adjusted in position within the gap between the ink flow path members 103,... And the insertion holes of the base plate 101, and the first camera 32 and the first plate The positional relationship with the two cameras 33 is equal to the positional relationship between the two head reference marks 105a and 105a when the recording head 102 is correctly positioned by adjusting the position of the second camera 33 in step S5. The first camera 32 and the second camera 33 can simultaneously recognize images of the two head reference marks 105a and 105a at corresponding positions.

  Then, as shown in FIGS. 7A, 7 </ b> B, and 8, the control unit 10 sets two head reference marks 105 a and 105 a in the image A of the first camera 32 and the image B of the second camera 33. Based on the recognition result, the X direction moving mechanism 22, the Y direction moving mechanism 23, and the head rotating unit 44 are controlled so that the recording head 102 and the base plate 101 are relatively translated and recorded. By rotating the recording head 102 about the approximate center of the head 102, the recording head 102 is positioned on the base plate 101.

  Specifically, each of the images A and B of the first camera 32 and the second camera 33 shows an allowable circle S indicating a positioning allowable range. In the images A and B, the two head reference marks 105a and 105a are simultaneously within the allowable circle S, and the line connecting the two head reference marks 105a and 105a on the images A and B and the X direction are formed. The X direction moving mechanism 22, the Y direction moving mechanism 23, and the head rotating unit 44 are appropriately controlled so that the angle θ is equal to or less than a predetermined value.

  For example, as shown in FIG. 7A, when the head reference mark 105a is out of the allowable circle S in either of the images A and B, or as shown in FIG. If the angle θ exceeds a predetermined value even if the head reference mark 105a is within the allowable circle S, the X-direction moving mechanism 22, the Y-direction moving mechanism 23, and the head rotating unit 44 are appropriately controlled. Then, as shown in FIG. 8, in the images A and B, the base plate 101 and the recording are performed so that the two head reference marks 105a and 105a are simultaneously within the allowable circle S and the angle θ is equal to or less than a predetermined value. The head 102 is relatively moved.

  Next, the control unit 10 fixes the recording head 102 positioned in step S7 to the base plate 101 (step S8). In this step, the control unit 10 controls the head fixing unit 5, and with respect to the recording head 102 that has been positioned on the base plate 101, the other one of the corners of the recording head 102 that is not gripped by the clamper 45. The diagonal portions of the set are screwed to the base plate 101. Thereafter, the control unit 10 controls the clamper 45 to release the recording head 102, controls the Z-direction moving mechanism 43 to retract the clamper 45 upward, and then controls the head fixing unit 5 again to control the clamper 45. A pair of diagonal portions gripped by the base plate 101 are screwed to the base plate 101.

  Next, the control unit 10 determines whether or not all the recording heads 102 are fixed to the base plate 101 (step S9), and if it is determined that they are not fixed (step S9; No), The process proceeds to step S7. If it is determined that all the recording heads 102 are fixed (step S9; Yes), the assembly of the head unit 100 is finished.

  Thus, by repeating steps S7 to S9, all the recording heads 102 are sequentially positioned and fixed to the base plate 101, and the head unit 100 is assembled.

  As described above, according to the head unit assembling method of the present embodiment, the recording head 102 is rotated and positioned on the base plate 101 around the approximate center of the recording head 102. Is not separated from the recording head 102 to be positioned, the positioning operation is simplified as compared with the conventional one, positioning in a short time is possible, and the recording head 102 can be precisely rotated to achieve high accuracy. Positioning can be performed. Therefore, the recording head 102 can be positioned with high accuracy in a short time as compared with the conventional case.

  Further, the clamper 45 holds a pair of diagonal portions of the recording head 102 toward the center on the diagonal line of the recording head 102 when the recording head 102 is positioned. Unlike the case where the recording head is held by engagement with the portion, it is possible to eliminate positioning error factors such as backlash due to biasing force when biasing the pin and backlash between the pin and the hole. Therefore, the recording head 102 can be positioned with higher accuracy.

  Further, since the two head reference marks 105a and 105a of the recording head 102 are simultaneously recognized by the two first cameras 32 and the second camera 33, the recording head 102 is positioned, so that one camera is moved. Compared with the case where positioning is performed while recognizing the two head reference marks, it is possible to prevent time loss and movement error associated with the movement of the camera, and positioning the recording head 102 in a shorter time with higher accuracy. can do.

  It should be noted that the present invention should not be construed as being limited to the above-described embodiment, and of course can be modified or improved as appropriate.

  For example, in the above embodiment, the base plate 101 is translated when the recording head 102 is positioned. However, the recording head 102 and the base plate 101 only need to be relatively translated, and the base plate 101 is stopped. Thus, the recording head 102 may be moved in translation.

  In addition, two head reference marks 105 a and 105 a are used as a plurality of reference portions for positioning the recording head 102. As the plurality of reference portions, the middle point of the plurality of nozzles 106 is the recording head 102. You may use the two nozzles 106 and 106 located in the approximate center. In the present embodiment, it is preferable that the two nozzles 106 and 106 that are farthest apart in the X direction have different columns in the Y direction (see FIG. 3).

  Further, two base plate reference marks 101a and two head reference marks 105a are formed, but two or more may be formed.

  Further, when the recording heads 102 are positioned and fixed, the plurality of recording heads 102 are sequentially positioned and fixed in accordance with a preset positioning order. For example, a different serial number is assigned to each recording head 102 in advance. May be set, and only the recording head 102 having the reference number designated by the user may be positioned and fixed.

  In addition, the first camera 32 and the second camera 33 are each adjusted in focus by a focus adjustment mechanism 34 provided therein, but instead of the focus adjustment mechanism 34, the first camera 32 and the second camera 33 are mounted on the support bed 21 of the base plate support unit 2. A lift actuator may be provided, and the focus adjustment may be performed by moving the base plate 101 and the recording head 102 on the support bed 21 in the Z direction by the lift actuator.

1 Head unit assembly device 5 Head fixing part (fixing means)
10 Control unit (control means)
22 X-direction moving mechanism (translation means)
23 Y-direction moving mechanism (translation moving means)
32 1st camera (recognition means)
33 Second camera (recognition means)
44 Head rotating part (head rotating means)
45 Clamper (gripping part)
100 Head unit 101 Base plate 101a Base plate reference mark 102 Recording head (inkjet head)
105a Head reference mark 106 Nozzle

Claims (8)

A head unit assembly device for positioning and fixing an inkjet head to a base plate,
Recognition means for recognizing a plurality of reference portions of the inkjet head and a plurality of reference marks of the base plate;
Translational movement means for relatively translating the inkjet head and the base plate;
A head rotating means for rotating the inkjet head around a substantially center of the inkjet head;
Fixing means for fixing the inkjet head to the base plate;
Based on the recognition result by the recognizing means, the translation moving means and the head rotating means are controlled to position the inkjet head on the base plate, and the fixing means is controlled to position the positioned inkjet head. Control means for fixing to the base plate;
With
The head rotating means is provided with a gripping portion for gripping a pair of diagonal portions of the inkjet head formed in a square plate shape ,
2. The head unit assembling apparatus according to claim 1, wherein the fixing means screw-fastens another set of diagonal portions not gripped by the grip portion among the corner portions of the inkjet head to the base plate . The inkjet head has at least two nozzles that eject ink droplets and have a midpoint positioned substantially in the center of the inkjet head.
The head unit assembling apparatus according to claim 1, wherein the plurality of reference portions are the two nozzles. The inkjet head has two fiducial marks whose midpoint is located approximately at the center of the inkjet head,
The head unit assembling apparatus according to claim 1, wherein the plurality of reference portions are the two reference marks. The ink-jet head is temporarily fixed to the base plate so as to be movable relative to the base plate before being positioned on the base plate. Head unit assembly device. A head unit assembly method for positioning and fixing an inkjet head to a base plate,
Using the inkjet head having a plurality of reference parts,
Using the base plate having a plurality of reference marks,
Recognizing the plurality of reference portions and the plurality of reference marks;
Based on the recognition result in the recognition step, the inkjet head and the base plate are relatively translated, and the inkjet head is rotated by rotating the inkjet head around the substantially center of the inkjet head. A positioning step of positioning on the base plate;
A fixing step of fixing the inkjet head to the base plate;
With
In the positioning step and the fixing step, a pair of diagonal portions of the inkjet head formed in a square plate shape is gripped,
In the fixing step, among the corner portions of the inkjet head, another set of diagonal portions that are not gripped are screw-fastened to the base plate. As the inkjet head, one that has at least two nozzles that eject ink droplets and whose midpoint is located at the approximate center of the inkjet head is used.
6. The head unit assembling method according to claim 5, wherein the plurality of reference portions are the two nozzles . As the ink jet head, one having two reference marks whose midpoint is located at substantially the center of the ink jet head is used.
The head unit assembling method according to claim 5 , wherein the plurality of reference portions are the two reference marks . As the ink-jet head, wherein prior to the positioning step, according to any one of claims 5-7 you characterized by using what is temporarily fixed to the extent movable relative to the base plate Head unit assembly method.

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