JPH1134347A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink jet recorder in which the print quality is enhanced while reducing the size by adjusting the head gap. SOLUTION: The ink jet recorder comprises a carriage 14 arranged movably along a shaft 15, a print head 12 mounted on the carriage 14, a cap 21 covering the forward end of the print head 12, a cap holder 22 for holding the cap 21, means for generating a negative pressure in the cap 21, a head gap adjusting mechanism, and a drive source coupled with the negative pressure generating means and the gap adjusting mechanism through a rotation transmitting means. Since the drive source can be shared by the gap adjusting mechanism and the negative pressure generating means, a drive motor dedicated for adjustment of the head gap is not required and the size of the ink jet recorder can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet recording apparatus.

[0002]

2. Description of the Related Art Conventionally, in an ink jet recording apparatus, printing is performed by ejecting ink droplets from nozzles formed at the tip of a print head and attaching the ink droplets to printing paper. By the way, when printing is performed by the inkjet recording apparatus, as printing conditions for improving print quality, ink droplets ejected from nozzles are attached to accurate positions on printing paper, and when they are attached. It is necessary to increase the roundness of the dots formed on the printing paper and to reduce the number of satellite droplets generated separately from the ink droplets.

In order to satisfy the printing conditions,
It is necessary to make the distance between the leading end of the print head mounted on the carriage and the printing paper, that is, the head gap constant in accordance with the thickness of the printing paper. Therefore, both ends of the shaft for guiding the carriage are eccentric, and a lever attached to the eccentric portion is manually operated to adjust the head gap by rotating the shaft.

[0004]

However, in the above-described conventional ink jet recording apparatus, it is necessary to manually operate the lever. Therefore, when the printing paper is thick due to an operator's operation error, the head gap may be narrowed. When the printing paper is thin, the head gap may be widened. In this case, since the head gap cannot be made to correspond to the thickness of the printing paper, the printing quality cannot be improved.

A dedicated drive motor can be provided to adjust the head gap, and the head gap can be adjusted by driving the drive motor. The device becomes large. The present invention solves the problems of the conventional ink jet recording apparatus, and provides an ink jet recording apparatus capable of adjusting a head gap, improving print quality, and reducing the size. With the goal.

[0006]

For this purpose, in an ink jet recording apparatus of the present invention, a carriage movably disposed along a shaft, a print head mounted on the carriage, and a tip of the print head And a cap holder for holding the cap,
Negative pressure generating means connected to the inside of the cap for negative pressure inside the cap, a gap adjusting mechanism for adjusting a head gap, and connected to the negative pressure generating means and the gap adjusting mechanism via a rotation transmitting means. And a driving source.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a first state diagram of the ink jet recording apparatus according to the embodiment of the present invention, FIG. 2 is a second state diagram of the ink jet recording apparatus according to the embodiment of the present invention, and FIG. FIG. 4 is a third state diagram of the inkjet recording apparatus.
1 is a side view of an inkjet recording apparatus according to an embodiment of the present invention.

In the drawing, reference numeral 11 denotes an ink tank;
A print head 12 is attached to a front end (lower end in the figure) of the ink tank 11, and a nozzle group 13 including a plurality of nozzles for ejecting ink droplets supplied from the ink tank 11 is provided at the front end of the print head 12. It is formed. The print head 12 is mounted on a carriage 14,
The carriage 14 is moved in the directions of arrows A and B along a shaft 15 provided on a frame 16 of the ink jet recording apparatus. Therefore, the carriage 14
, A drive belt (not shown) is fixed, and the drive belt is driven by driving a carriage drive motor (not shown).

The shaft 15 has eccentric cams 17 at both ends.
And is supported by the frame 16 via the eccentric cam 17. And one of the eccentric cams 17 has
A gear 18 is disposed adjacent to the inner surface of the frame 16. Reference numeral 21 denotes a cap formed of rubber or the like and provided with an upper end opening toward the print head 12 side. The cap 21 is supported by a cap holder 22 and an ink absorber 23 is provided therein. Is done. A hole is formed in the bottom of the cap 21 and the cap holder 22, and an ink tube 24 is attached through the hole.

One end of the ink tube 24 faces the inside of the cap 21 and the other end is connected to the negative pressure generating means 3.
1 and a discharge ink receiving portion 32 is connected further ahead of the negative pressure generating means 31. By the way, the cap holder 22 moves to the retracted position shown by the solid line in FIG. 1, the cap closed position shown by the solid line in FIG. 2, and the gap adjustment position shown in FIG. In the retracted position, the cap 21
Moves away from the tip of the print head 12, and in the cap closed position, the cap 21 covers the tip of the print head 12,
The nozzle group 13 is sealed.

For this purpose, the cap holder 22 is
The cap frame (not shown) is movably supported in the directions of arrows C and D, and is urged in the direction of arrow D. The carriage 1 is provided at one end of the cap holder 22 at the cap closing position and the gap adjusting position.
The ribs 22a to be brought into contact with 4 are integrally formed. Reference numeral 20 denotes a motor gear rotatably supported on the frame 16. The motor gear 20 includes a large gear 20 a and a small gear 20 b integrally formed, and serves as a drive source fixed to the frame 16. Drive motor 29
Is driven to rotate. Further, a change gear 19 as a rotation transmitting means is removably disposed between the gear 18 and the motor gear 20, and the change gear 19 includes the change gear 19, the gear 18 and the large gear as shown in FIG. The gear 20a meshes with and meshes with the drive motor 29 and the negative pressure generating means 31 and the gap adjusting mechanism, and the change gear 19, the gear 18, and the large gear 20a as shown in FIGS. And a release position at which the engagement with is released.

Therefore, the change gear 19 is mounted on the post 1
9b rotatably supports the frame 16 and is urged by a spring 19a toward a side away from the gear 18 and the large gear 20a. The drive motor 29 and the negative pressure generating means 31 are connected to the small gear 20b and the idle gear 30 as a rotation transmitting means.
a through 30c, and drives the drive motor 29 in the forward or reverse direction to operate the negative pressure generating means 31. The negative pressure generating means 31
To a negative pressure.

In the present embodiment, the cap holder 2
When the cap 2 is placed at the cap closing position, the cap holder 22 is detected by a sensor (not shown). Then, when receiving a detection signal from the sensor, the control unit (not shown) drives the drive motor 29 for a predetermined time and activates the negative pressure generating means 31 for a predetermined time. It should be noted that the drive motor 29 can always be driven regardless of whether the cap holder 22 is in the retracted position, the cap closed position, or the gap adjustment position.

Further, the drive motor 29 can be selectively driven in a forward direction and a reverse direction. Next, the operation of the ink jet recording apparatus will be described. First, the carriage driving motor is driven by an instruction of the control unit, and the carriage 14 is moved in the direction of arrow A from the left in FIG. 1. When the carriage 14 reaches the home position _SHG , the right side of the carriage 14 is The carriage 14 and the rib 22a are locked on the end face. Thereafter, when the carriage 14 is further moved in the direction of the arrow A, the cap holder 22 is moved in conjunction with the carriage 14 and gradually approaches the carriage 14 side by the cap frame. In this manner, the cap holder 22 is moved in the direction of arrow C, and is placed in the cap closed position as shown in FIG. 2, the tip of the print head 12 is covered by the cap 21, and the nozzle group 13 is sealed. You.

In this state, the drive motor 29
Is driven in the positive direction, and a negative pressure is generated by the negative pressure generating means 31, the inside of the cap 21 connected via the ink tube 24 becomes a negative pressure. Therefore, ink is sucked from the nozzle group 13 and ink residue, minute dust, and the like are removed from each nozzle. The sucked ink is discharged to the discharged ink receiving section 32 via the ink tube 24.

When the carriage 14 is further moved in the direction of arrow A, the change gear 19
When the cap holder 22 is placed at the gap adjustment position shown in FIG. 3 against the urging force of FIG. 20a are engaged with each other. Therefore, when the drive motor 29 is driven in the forward direction in this state, the rotation of the drive motor 29 is transmitted to the gear 18 via the large gear 20a and the change gear 19.

When the carriage 14 is moved in the direction of arrow B and the cap holder 22 is moved from the gap adjusting position to the cap closing position, the change gear 1 is moved.
9 is located at the release position, and the meshing of the change gear 19 with the gear 18 and the large gear 20a is released. Therefore, the rotation from the drive motor 29 is not transmitted to the gear 18.

Then, the carriage 14 is further moved in the direction of arrow B, and the cap holder 22 is moved in the state where the carriage 14 and the rib 22a are locked.
When the cap holder 22 is moved from the cap closed position to the retracted position in conjunction with the cap frame, the cap holder 22 is slightly separated from the carriage 14 by the cap frame during this time. Thus, the cap holder 22 is moved in the direction of arrow D. Then, the carriage 14
Is further moved in the direction of arrow B, the carriage 14
After that, the lock between the carriage 14 and the rib 22a is released, only the carriage 14 is moved in the direction of arrow B, and the cap holder 22 is stopped at the retracted position.

Next, a gap adjusting mechanism for adjusting the head gap will be described. FIG. 5 is a diagram showing a gap adjusting mechanism according to the embodiment of the present invention.
In the figure, 11 is an ink tank, 12 is a print head,
13 is a nozzle group, 14 is a carriage, 15 is a shaft,
17 is an eccentric cam, 18 is a gear, and 35 is a printing paper.
L is a head gap. The shaft 15 and the eccentric cam 17 constitute a gap adjusting mechanism.

In the gap adjusting mechanism having the above-described structure, the carriage 14 is moved by an arrow A in accordance with an instruction from a control unit (not shown).
When a sensor (not shown) detects that the cap holder 22 has reached the gap adjustment position in the direction (FIG. 1), the control unit drives the drive motor 29 in the forward direction, and moves the motor gear 20 in the direction shown in FIG. Rotate counterclockwise at 4. At this time, the rotation of the drive motor 29 is transmitted to the gear 18 via the change gear 19,
8 and the eccentric cam 17 are rotated in the direction of arrow E. Here, since the shaft 15 is eccentric with respect to the center of the eccentric cam 17, the rotation of the eccentric cam 17 in the direction of the arrow E moves the shaft 15 to a position a shown by a broken line. Therefore, the carriage 14 supported by the shaft 15 and the print head 12 and the ink tank 11 mounted on the carriage 14 are moved in the direction of arrow G. As a result, the head gap L can be reduced.

When the control unit drives the drive motor 29 in the reverse direction and rotates the motor gear 20 clockwise in FIG. 4, the rotation of the drive motor 29 is changed by the change gear 1.
9, the gear 18 and the eccentric cam 17 are rotated in the direction of arrow F. Then, by the rotation of the eccentric cam 17 in the direction of the arrow F, the shaft 15 is moved to a position b indicated by a broken line. Therefore, the carriage 14 supported by the shaft 15 and the print head 12 and the ink tank 11 mounted on the carriage 14 are moved in the direction of arrow H. as a result,
The head gap L can be increased.

In this case, the control section sets the number of revolutions or the number of pulses of the drive motor 29. By changing the setting of the number of revolutions or the number of pulses, the position of the shaft 15 is adjusted. And printing paper 35
The head gap L can be adjusted according to the thickness of the head. Then, in order to change the setting of the number of revolutions or the number of pulses, a higher-level device (not shown), for example, a host computer, gives instructions to the inkjet recording apparatus by changing a menu of a printer driver, or operates buttons on an operation panel. Can be given to the ink jet recording apparatus by operating the operator.

When the drive motor 29 is driven in the forward direction, the print head 12 and the ink tank 11
When moved in the same direction, the cap holder 22 is stopped at the same gap adjustment position,
There is a possibility that the cap 21 covering the tip of the print head 12 is deformed and the inside of the cap 21 becomes a positive pressure. However, in this case, since the drive motor 29 is driven in the positive direction, the negative pressure generating means 31 is operated and the cap 2
A minute negative pressure is generated inside the unit 1. As a result, the positive pressure due to the deformation of the cap 21 is offset by the negative pressure, so that the generation of the positive pressure can be prevented.

When the drive motor 29 is driven in the reverse direction and the print head 12 and the ink tank 11 are moved in the direction of arrow H, the negative pressure generating means 31 is actuated and the inside of the cap 21 is moved. A small negative pressure is generated. As described above, in the present embodiment, the common drive motor 29 can be used as a drive source of the gap adjustment mechanism for adjusting the head gap L and as a drive source of the negative pressure generating means 31. Therefore, there is no need to provide a dedicated drive motor for adjusting the head gap. Therefore, the size of the ink jet recording apparatus can be reduced.

Further, since it is not necessary to operate a lever (not shown) or the like to adjust the head gap L, if the printing paper 35 is thick due to an operator's operation error, the head gap L can be reduced or the printing paper 35 can be reduced. Is small, the head gap L is not increased.
Therefore, since the head gap L can be made to correspond to the thickness of the printing paper 35, the printing quality can be improved.

The present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0027]

As described above in detail, according to the present invention, in an ink jet recording apparatus, a carriage movably disposed along a shaft, a print head mounted on the carriage, A cap for covering the tip of the print head, a cap holder for holding the cap, a negative pressure generating means connected to the inside of the cap for generating a negative pressure inside the cap, and a gap adjusting mechanism for adjusting the head gap And a drive source connected to the negative pressure generating means and the gap adjusting mechanism via a rotation transmitting means.

In this case, the drive source of the gap adjusting mechanism for adjusting the head gap and the drive source of the negative pressure generating means can be used in common, so that a dedicated drive motor is used for adjusting the head gap. Need to be installed. Therefore, the size of the ink jet recording apparatus can be reduced. In addition, since it is not necessary to operate a lever or the like to adjust the head gap, the operator may reduce the head gap when the printing paper is thick or increase the head gap when the printing paper is thin due to an operation error of the operator. No more. Therefore, since the head gap can be made to correspond to the thickness of the printing paper, the printing quality can be improved.

[Brief description of the drawings]

FIG. 1 is a first state diagram of an ink jet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a second state diagram of the inkjet recording apparatus according to the embodiment of the present invention.

FIG. 3 is a third state diagram of the ink jet recording apparatus according to the embodiment of the present invention.

FIG. 4 is a side view of the ink jet recording apparatus according to the embodiment of the present invention.

FIG. 5 is a diagram showing a gap adjusting mechanism according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 12 print head 14 carriage 15 shaft 17 eccentric cam 19 change gear 21 cap 22 cap holder 29 drive motor 30a-30c idle gear 31 negative pressure generating means

Claims (2)

[Claims] (A) a carriage movably disposed along a shaft; (b) a print head mounted on the carriage; and (c) a cap for covering a tip of the print head. (D) a cap holder for holding the cap, (e) negative pressure generating means connected to the inside of the cap and for generating a negative pressure inside the cap, and (f) a gap adjusting mechanism for adjusting the head gap. (G) An ink jet recording apparatus comprising: a driving source connected to the negative pressure generating means and the gap adjusting mechanism via a rotation transmitting means. (A) the cap holder selectively takes a retreat position, a cap closing position, and a gap adjusting position with movement of a carriage, and (b) when the cap holder is placed at the cap closing position. (C) when the cap holder is placed at the gap adjusting position, the driving source is connected to the negative pressure generating means and the gap adjusting mechanism. The ink jet recording apparatus according to claim 1.