JP2001179951A - Ink jet imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet imaging apparatus in which a highly accurate positional relation can be kept between a print head and a recording medium. SOLUTION: The position for securing a head holder 60 to a slide base 40 is made adjustable using three eccentric dowels 201, 202, 203.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet type image forming apparatus for forming an image on a recording medium while reciprocating a print head for discharging ink in a predetermined direction.

[0002]

2. Description of the Related Art As one of output devices of computers and workstations, there is known an image forming apparatus of an ink jet system which forms an image on a recording medium such as recording paper by discharging ink. The inkjet type image forming apparatus includes, for example, a print head in which a plurality of ink ejection ports for ejecting ink are formed, a carriage on which the print head is mounted and which reciprocates in a predetermined direction, and which is orthogonal to the predetermined direction. And a transport device for transporting the recording paper in the direction.

When an image is formed on a recording sheet, generally, the recording sheet being conveyed by the conveying device is temporarily stopped, and the image signal carrying the image information is moved while the carriage is reciprocated in the predetermined direction. The ink is ejected from the ink ejection port on the basis of the above, and an image for one band is formed on a portion of the recording paper located in the image forming area facing the ink ejection port. After that, the recording paper is conveyed by one band and stopped.
Again, while the carriage reciprocates in the above-described predetermined direction, ink is ejected from the ink ejection ports based on the image signal, and an image is formed on a portion of the recording paper that is newly located in the image forming area. By repeating such an operation, an image is formed on the recording paper.

In the above-described ink jet type image forming apparatus, a guide rail extending in the above-described predetermined direction is generally formed, and a carriage is fixed to the guide rail so as to be able to reciprocate. However, there are various shapes of the print head mounted on the carriage, and it is necessary to re-create the carriage according to the shape of the print head mounted. For this reason, the cost of remanufacturing the carriage is increased, and the cost of the mold for manufacturing the carriage is also increased, thereby increasing the cost of the entire apparatus. In particular,
In the case of a large carriage, the cost of the mold increases, and the cost of the entire apparatus further increases.

Therefore, a carriage unit in which a carriage is divided into a head holder on which a print head is mounted and a slide base to which the head holder is detachably fixed is sometimes used. In this carriage unit,
The slide base is fixed to the guide rail and reciprocates in a predetermined direction. When using a carriage unit divided into a head holder and a slide base in this way,
Each component becomes smaller. Therefore, even if the head holder is re-manufactured according to the shape of the print head, the cost is lower than the cost of re-manufacturing the integral carriage.

[0006]

In order to form an accurate image and maintain high image quality, it is desirable that the distance between the print head and the recording paper be exactly constant.
However, the accuracy of various components such as the above-described carriage unit and guide rail often has some errors. If errors occur in a plurality of components and these accumulate, the distance or angle between the print head and the recording paper may change.
In particular, in the above-described divided carriage unit, an error may occur in both the head holder and the slide base, and the distance and the angle between the print head and the recording paper are likely to change.
For this reason, it is difficult to form an accurate image, and it may not be possible to maintain high image quality.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide an ink jet type image forming apparatus capable of maintaining a high positional relationship between a print head and a recording medium.

[0008]

In order to achieve the above-mentioned object, the present invention provides a print head for reciprocating in a predetermined direction a slide base to which a head holder mounted with a print head for ejecting ink is detachably fixed. An ink jet type image forming apparatus which forms an image on a portion of a recording medium located in the image forming area in front of the print head by ejecting ink from the printer, (1) fixing the head holder to the slide base An adjustment mechanism for adjusting the position is provided.

Here, (2) the adjusting mechanism may adjust the fixed position by moving the head holder.

(3) The head holder has at least three first abutting portions which move in a first direction orthogonal to the predetermined direction and abut, and at least one second abutting member which moves in the predetermined direction and abuts. An abutting portion, and at least two third abutting portions that move and abut in a third direction orthogonal to both the first direction and the predetermined direction. (4) The slide base is A fourth abutting portion that abuts the first abutting portion, a fifth abutting portion that abuts the second abutting portion, and a sixth abutting portion that abuts the third abutting portion, (5) The adjusting mechanism is configured to be connected to the first
At least one of the abutting portion and the sixth abutting portion may be moved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an ink jet type image forming apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a schematic configuration of a plotter which is an example of an ink jet type image forming apparatus of the present invention.

The plotter 10 has a platen 14 on which the recording paper 12 conveyed in the direction of arrow A is placed. Above the platen 14, two guide rails 16 are extended in parallel with the platen 14. A slide base 40 is fixed to the guide rail 16 so as to freely reciprocate in directions indicated by arrows B and B '(a direction orthogonal to the direction of arrow A) by a motor (not shown) and a belt (not shown). . The slide base 40 has a print head 20 having an ink ejection port (not shown) for ejecting ink.
Is mounted detachably. The carriage unit 30 is constituted by the slide base 40 and the head holder 60.

An image forming area 18 on which an image is formed is located in front of the ink discharge port of the print head 20 mounted on the head holder 60. Ink is ejected from the ejection port to form an image. FIG. 1 shows a schematic configuration of the print head 20, the slide base 40, and the head holder 60. Further, in FIG. 1, the print heads 20 are represented as one print head 20. However, in actuality, as shown in FIG.
C (cyan), 20M (magenta) and 20Y (yellow).

In forming an image on the recording paper 12,
The recording paper 12 is placed on the platen 14, and the recording paper is transported to a conveying roller 22 having a part of the outer peripheral surface exposed from an opening (not shown) formed in the platen 14, and both ends in the width direction of the recording paper 12. The portion is nipped by a pinch roller 24 that presses from above, and is transported by rotating a transport roller 22 by a motor (not shown). The slide base 40 is reciprocated in the directions of arrows B and B ′ above the recording paper 12, and ink is ejected based on an image signal carrying image information transmitted from the control device 26 to the print head 20, and the recording paper is discharged. Out of 12,
An image is formed on a portion located in the image forming area 18.

The carriage unit 30 will be described with reference to FIGS.

FIG. 2 is a perspective view showing the carriage unit of FIG. 1, and FIG. 3 is a perspective view showing a slide base of the carriage unit of FIG. FIG. 4 is a perspective view showing a head holder on which a print head is mounted. Also,
FIG. 5 is a side view showing a part of the carriage unit cut away, and FIG. 6 is a plan view of the carriage unit.

As described above, the carriage unit 30 includes the slide base 40 which freely reciprocates in the directions of arrows B and B ', and the head holder 60 which is detachably fixed to the slide base 40. The slide base 40 and the head holder 60 are respectively formed with opposing surfaces 42 and 62 which oppose each other when both are fixed. The facing surface 42 of the slide base 40 has an arrow A
A U-shaped convex surface 42a protruding in the direction (an example of a first direction according to the present invention) and a concave surface 42b formed at a position recessed in the direction of the arrow A 'are formed. , 42b is formed with a step.

As shown in FIG. 4, a first abutting portion 64 protruding in the direction of arrow A 'is formed above the opposing surface 62 of the head holder 60. As shown in FIG. 3, the first eccentric piece 201 (the fourth eccentric piece 201 according to the present invention) is provided on the convex surface 42 a on the upper surface of the opposing surface 42 of the slide base 40 as the one that abuts on the distal end surface 64 a of the first abutting portion 64. (Which is an example of the abutting portion) is fixed. This first eccentric piece 201
Has a columnar shape with an elliptical cross section, and a part thereof is exposed.

Further, as shown in FIG.
In the lower portion of the opposing surface 62, two first abutting portions 6 each having an inverted L shape are also provided at both ends in the directions of arrows B and B '.
6, 68 are formed. These two first butting parts 6
6, 68 inner surface 66a (see FIG. 5), 68a (surface 68).
As shown in FIG. 5, a protrusion 50 on one side surface 46 of the slide base 40 has a second eccentric top 202 (an example of a fourth abutment portion according to the present invention). Is fixed.) This second eccentric top 20
Numeral 2 is a column having an elliptical cross section, and a part thereof is exposed. Also, the other side surface 48 of the slide base 40
As shown in FIG. 6, a columnar convex portion 52 (which is an example of a fourth abutment portion in the present invention) is formed on the first portion. Here, the second eccentric piece 202 and the outer peripheral surface 52a of the convex portion 52
9 (see FIG. 9) abut against the inner side surfaces 66a, 68a of the first abutting portions 66, 68, respectively.

A leaf spring 54 for urging the head holder 60 in the direction of arrow A (in the direction away from the slide base 40) is fixed below the opposed surface 42b of the slide base 40. As shown in FIG. 5, this leaf spring 54
The head holder 60 is pushed in the direction of arrow A. However, since the inner side surfaces 66a and 68a of the first abutting portions 66 and 68 abut against the second eccentric top 202 and the outer peripheral surface 52a of the convex portion 52, the movement in the directions of the arrows A and A 'is prohibited. These stopping positions are determined.

The opposite surface 42b of the slide base 40
A coil spring 72 is stretched between an inverted L-shaped projection 56 formed at the center of the head holder 60 and a projection 70 formed at the center of the facing surface 62 of the head holder 60. The coil spring 72 is provided between the slide base 40 and the head holder 6.
It works to draw (close) 0 to each other. As shown in FIG. 5, the opposing surface 42a of the slide base 40 and the opposing surface 62 of the head holder 60 are moved by the coil spring 72.
Are attracted to each other. However, since the first abutting portion 64 abuts on the first eccentric piece 201, the movement in the directions of the arrows A and A 'is prohibited, and the positions where these stop are determined.

As shown in FIG. 3, a leaf spring 58 for pressing the head holder 60 in the direction of arrow B 'is fixed to the side surface 46 of the slide base 40. On the other hand, the head holder 60
On the side surface of the first abutting portion 68, a second abutting portion 74 projecting in the direction of arrow B 'is formed. As shown in FIG. 6, the second abutting portion 74 is formed by the leaf spring 58 so that the second abutting portion 74 is a side surface 48 of the slide base 40 (here, an example of a fifth abutting portion).
Attracted to. However, since they abut each other, movement in the directions of these arrows B and B 'is prohibited,
These stopping positions are determined. As described above, the head holder 60 is moved by the arrow B and the arrow B by one second abutting portion 74, one fifth abutting portion (side surface 48), and the leaf spring 58.
Moving in the direction B 'is prohibited.

The head holder 60 is pulled in the direction of arrow C 'by the coil spring 72 described above. But the first
The inner surfaces 66b, 68b of the abutments 66, 68 are the fourth abutments 5
0 and the third eccentric piece 203.
This prohibits the head holder 60 from moving in the directions of arrows C and C ′. Therefore, here, the first butting portion 6
6, 68 are the third butting portions (66b, 68) according to the present invention.
The fourth abutting portions 50 and 52 also serve as the sixth abutting portions (50b) according to the present invention. The third eccentric piece 203 is fixed to the fourth abutting portion 52 with a part thereof being exposed, and the third eccentric piece 203 is an example of the sixth abutting portion according to the present invention.

As described above, the first to sixth abutting portions 64, 201 (first eccentric pieces), 66a, 68a, 2
02 (second eccentric top), 52a, 66b, 68b, 50
b, 203 (third eccentric top), 74, 48, leaf spring 5
4, 58 and the coil spring 72, the arrow A,
Since the head holder 60 is prohibited from moving in directions perpendicular to each other indicated by A ', B, B', C, and C ', the positioning between the head holder 60 and the slide base 40 can be accurately performed. The directions of the arrows B and B 'are examples of the second direction according to the present invention. The directions of arrows C and C ′ are examples of the third direction according to the present invention. Further, the three eccentric pieces 201, 202, and 203 constitute an example of the adjusting mechanism according to the present invention.

The adjustment of the fixed position where the head holder is fixed to the slide base will be described with reference to FIGS.

FIG. 7 is a plan view showing the first eccentric coma viewed from the direction of arrow C '. FIG. 8 is a plan view showing the second eccentric top viewed from the direction of arrow B. FIG. 9 is a plan view showing the third eccentric coma viewed from the direction of arrow B ′. FIG.
It is a perspective view which shows the joining position of a 1st contact part and a convex part. FIG.
FIG. 1 is a plan view of the joint state of the first contact portion, the convex portion, and the third eccentric piece viewed from the direction of arrow B.

As shown in FIG. 7, the first eccentric piece 201
Is fixed to the slide base 40 so that it can freely rotate (rotate) in the direction of arrow D, and a part thereof is
It is exposed from. The rotation center of the first eccentric piece 201 is the first eccentric piece 201 itself. An eccentric surface 201a is formed on a portion of the outer peripheral surface of the first eccentric piece 201 that is exposed from the surface 42a with a radius smaller than that of the outer peripheral surface of the first eccentric piece 201 within a range of a central angle of about 90 °. ing. The eccentric surface 201a is eccentric with respect to the rotation center of the first eccentric piece 201. The top surface (top surface) of the first eccentric piece 201 is formed with a driver long hole 201b into which the tip of a driver (not shown) is inserted.

The tip of the driver is inserted into the long slot 201 for the driver.
b, when the first eccentric piece 201 is rotated in the direction of arrow D, the height of the head holder 60 with respect to the distal end surface 64a of the first abutting portion 64 changes, and the shaft ( The head holder 60 rotates around the (virtual axis) as a central axis. Thereby, the position around the above-mentioned center axis among the fixed positions where the head holder 60 is fixed to the slide base 40 can be adjusted. Therefore, the parallelism between the portion of the recording paper located in the image forming area and the ink ejection surface of the print head 20 (see FIG. 1) can be adjusted, and variations in ink droplet landing in the band can be suppressed.

As shown in FIG. 8, the second eccentric piece 202
Is fixed to the convex portion 50 of the slide base 40 so as to freely rotate (rotate) in the direction of the arrow E, and a part thereof is exposed from the surface 50a. The rotation center of the second eccentric top 202 is the second eccentric top 202 itself. An eccentric surface 202a is formed in a portion of the outer peripheral surface of the second eccentric top 202 that is exposed from the surface 50a with a radius smaller than that of the outer peripheral surface of the second eccentric top 202 within a range of a central angle of about 90 °. ing. The eccentric surface 202a is eccentric with respect to the rotation center of the second eccentric piece 202. The top surface (top surface) of the second eccentric piece 202 is formed with a driver long hole 202b into which the tip of a driver (not shown) is inserted.

The tip of the driver is inserted into the long hole 202 for the driver.
b, and when the second eccentric piece 202 is rotated in the direction of arrow E, the head holder 6 with respect to the first abutting portion 66a is rotated.
The height of 0 changes, and the head holder 60 rotates around an axis (virtual axis) extending in the directions of arrows C and C ′. Thereby, among the fixed positions where the head holder 60 is fixed to the slide base 40, the position around the central axis extending in the directions of arrows C and C 'can be adjusted. Accordingly, it is possible to adjust the inclination of the ink ejection row of the print head 20 (see FIG. 1) with respect to the recording paper transport direction, and to eliminate the printing deviation in the direction of the vertical line (the straight line extending in the directions of arrows A and A ') of the band matching portion. Let

As shown in FIGS. 9 and 10, the third eccentric piece 203 is fixed to the convex portion 52 of the slide base 40 so that it can freely rotate (rotate) in the direction of arrow F. Are exposed from the surface 52a. The rotation center of the third eccentric piece 203 is the third eccentric piece 203 itself.
The portion of the outer peripheral surface of the third eccentric piece 203 that is exposed from the surface 52a has an eccentric surface 203 having a radius smaller than the outer peripheral surface of the third eccentric piece 203 within a range of a central angle of about 90 °.
a is formed. The eccentric surface 203a is eccentric with respect to the rotation center of the third eccentric piece 203. The top surface (top surface) of the third eccentric piece 203 is formed with a driver long hole 203b into which the tip of a driver (not shown) is inserted.

The tip of the driver is inserted into the long hole 203 for the driver.
b, and the third eccentric piece 203 is rotated in the direction of arrow F, so that the head holder 6 with respect to the third abutting portion 66b is rotated.
The height of 0 changes, and the head holder 60 rotates around an axis (virtual axis) extending in the directions of arrows A and A '. Thereby, among the fixed positions where the head holder 60 is fixed to the slide base 40, the position around the central axis extending in the directions of arrows A and A 'can be adjusted. Therefore, the distance from the portion (image forming portion) of the recording paper located in the image forming area to the ink ejection port of the print head is adjusted. By this adjustment, the four print heads 2 from the image forming portion
The difference between the distances to 0K, 20C, 20M, and 20Y (see FIG. 2) can be minimized. As a result, variations in the landing of ink droplets in the four print heads 20K, 20C, 20M, and 20Y can be suppressed.

The three eccentric pieces 201, 202, 2
03 is fixed by bonding to the slide base 40 after the fixing position where the head holder 60 is fixed to the slide base 40 is adjusted.

In the above-described embodiment, the fixing position where the head holder 60 is fixed to the slide base 40 is adjusted by adjusting the heights of the three abutting portions. However, the number of adjustment positions may be reduced. On the contrary, when fine adjustment is performed, the number of adjustment portions may be increased. In the above-described embodiment, the fixed position is adjusted using the three eccentric pieces 201, 202, and 203. However, the height is not limited to the eccentric piece as long as the height of the abutting portion can be adjusted, and a screw or the like may be used. . Further, a component for adjusting the height of the abutting portion may be adjusted to be relatively large in advance, and may be deleted and adjusted as necessary.

In the above embodiment, the slide base 40 is provided with an adjusting mechanism (three eccentric pieces 201, 202, 2).
Although 03) is provided, a part or all of the adjusting mechanism may be provided on the head holder 60, and the same effect can be obtained in this case as well. Further, in the present invention, it is assumed that the fixing position is adjusted when assembling the inkjet type image forming apparatus. However, the adjustment of the second eccentric top 202 which is easy to determine by viewing the output image (the image formed on the recording medium). For the above (adjustment of vertical line shift), a lever or the like may be provided so that the user can make adjustments.

[0037]

As described above, in the ink jet type image forming apparatus of the present invention, an error occurs in the accuracy of parts such as the head holder and the slide base, and the position of the print head with respect to the image forming area is caused by the error. Even if it shifts,
Since the fixing position can be adjusted by the adjusting mechanism, the position of the print head with respect to the image forming area can be adjusted. Therefore, the positional relationship between the print head and the recording medium can be maintained with high accuracy, and a high-quality image can be obtained.

Here, when the adjusting mechanism adjusts the fixed position by moving the head holder, the fixed position can be adjusted simply by moving the head holder, so that the fixed position can be easily adjusted. .

The head holder includes a first abutment, a second abutment, and a third abutment, and the slide base includes a fourth abutment and a fifth abutment. And a sixth abutting portion, wherein the adjusting mechanism moves at least one of the first abutting portion to the sixth abutting portion. Since the fixed position can be adjusted only by moving at least one of the first to sixth abutting portions, the fixed position can be more easily adjusted.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a plotter which is an example of an inkjet type image forming apparatus of the present invention.

FIG. 2 is a perspective view showing the carriage unit of FIG. 1;

FIG. 3 is a perspective view showing a slide base of the carriage unit of FIG. 2;

FIG. 4 is a perspective view showing a head holder on which a print head is mounted.

FIG. 5 is a side view showing a part of the carriage unit in a cutaway manner.

FIG. 6 is a plan view of the carriage unit.

FIG. 7 is a plan view showing a first eccentric coma viewed from the direction of arrow C ′.

FIG. 8 is a plan view showing a second eccentric coma viewed from the direction of arrow B.

FIG. 9 is a plan view showing a third eccentric coma viewed from the direction of arrow B ′.

FIG. 10 is a perspective view showing a joint position between a first contact portion and a convex portion.

FIG. 11 is a plan view showing a state in which the first contact portion, the convex portion, and the third eccentric piece are joined together as viewed from the direction of arrow B;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Plotter 20K, 20C, 20M, 20Y Print head 30 Carriage unit 40 Slide base 48 Fifth abutment part 60 Head holder 64, 66, 68 First abutment part 74 Second abutment part 201 First eccentric piece 202 Second Eccentric top 203 Third eccentric top

Claims (3)

[Claims] An ink is ejected from the print head while reciprocating in a predetermined direction a slide base to which a print head for ejecting an ink is mounted, the head holder being removably fixed, and a print head of the print medium is formed. An ink jet image forming apparatus for forming an image on a portion located in a front image forming area, comprising: an adjusting mechanism for adjusting a fixing position at which the head holder is fixed to the slide base. Forming equipment. 2. The inkjet image forming apparatus according to claim 1, wherein the adjustment mechanism adjusts the fixed position by moving the head holder. 3. The head holder comprises: at least three first abutting portions that move and abut in a first direction orthogonal to the predetermined direction; and at least one second abutting portion that abuts by moving in the predetermined direction. And the first
And at least two third abutting portions that move and abut in a third direction orthogonal to both the first direction and the predetermined direction, wherein the slide base abuts the first abutting portion. And a fifth abutment part abutting on the second abutment part, and a sixth abutment part abutting on the third abutment part, wherein the adjusting mechanism comprises: the first abutment part. The image forming apparatus according to claim 1, wherein at least one of the first to sixth abutting portions is moved.