JPH06345284A - Belt conveyor and intermediate transfer type ink jet recording apparatus using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] A belt conveying device prevents a meandering force by removing the belt's meandering force, and obtains a high-quality recording or highly accurate conveying device. [Structure] A separation plate 6 is provided coaxially with a driven roller 5 of a belt conveying device, and the belt 1 and the driven roller 5 are disengaged from each other while the separation plate 6 is rotating to prevent the belt from meandering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt conveyor which rotates and circulates, and a belt conveyor having a belt meandering preventing means, and an intermediate transfer type ink jet recording apparatus having the belt meandering preventing means mounted thereon. The present invention relates to an intermediate transfer type inkjet recording device.

[0002]

2. Description of the Related Art In a conveying device for an endless belt (hereinafter referred to as a belt) stretched between a plurality of rollers, belt meandering prevention is an important issue, and many meandering preventing devices have been considered. As a general conventional technique for preventing such belt meandering, there is a device shown in FIG.

FIG. 9A shows a method in which the driving roller is formed into a crown shape and the belt is moved to the center of the driving roller, and FIG.
Is a method in which a hole is provided near the end surface of the belt and a sprocket wheel is provided on the drive roller side to engage the hole to eliminate meandering. In FIG. , There is a method of preventing meandering by providing a groove engaging with the groove on the drive roller side.

A problem with the above-mentioned device is that the belt is wrinkled near the center (FIG. 9 (a)), and the material of the belt is stretchable (FIG. 9 (a)). The accuracy of time is not good (Figs. 9 (a), 9 (b), and 9 (c)), and the running guide rib is not durable due to repeated rib compression / expansion (Fig. 9 (c)). Problems occur, and in practical use, there are limitations on materials used and technical problems.

Further, in recent years, as a field of application of the belt conveying device, it is widely used in devices such as laser printers, color printers, and copying machines, and running accuracy is required for a photosensitive belt, a recording paper conveying belt, and the like. It is used in the place. The belt material of belt conveyors used for such applications includes plastic films, metal foils, etc., which are often thin, have low elongation, and have high strength. Since it is difficult to deform, it is not possible to absorb dimensional errors of related parts, roller member mounting errors, belt tension imbalance, uneven belt circumference, etc. by the deformation of the belt itself. Sometimes there is a problem that it is easy to meander. As measures against this, Japanese Patent Publication No. 4-51451 and Japanese Unexamined Patent Publication No. 4-1
As disclosed in Japanese Patent No. 48746, there has been proposed a device that detects a deviation of a belt and corrects meandering in a mechanical structure.

On the other hand, the above-mentioned intermediate transfer type ink jet recording apparatus is a printer having a feature that ink jet clogging caused by unintentional contact between recording paper or paper dust and a recording head does not occur and high reliability is obtained. . As such an intermediate transfer type inkjet recording device,
US Pat. No. 4,538,156, US Pat. No. 509
The structures described in Japanese Patent No. 9256 and Japanese Patent Laid-Open No. 62-92849 are known. This apparatus is provided with an ink jet recording head (hereinafter, referred to as a recording head) having a plurality of nozzles with a gap formed in a cylindrical transfer medium. When an ink image is formed on the transfer medium by this recording head. The recording head moves in the direction parallel to the nozzles in synchronization with the rotation of the cylindrical transfer medium to form an ink image on the cylinder. Then, the recording medium is brought into contact with the transfer medium and pressed from the back of the recording medium to transfer the ink image onto the recording medium, and the recording medium is conveyed in the paper discharge direction.

[0007]

[Problems to be Solved by the Invention] However, Japanese Patent Publication No. 4
In the configurations disclosed in Japanese Patent Laid-Open No. 51451 and Japanese Patent Laid-Open No. 4-148746, it is premised that the belt is meandering, and a method of detecting the deviation amount of the belt and electrically or mechanically correcting the method. When the belt transport mechanism having these configurations is used as a transfer medium (in the present invention, an endless belt-shaped belt is used) of the intermediate type inkjet recording apparatus, the belt has a meandering, At the time of writing, the recording head ejects ink while writing an ink image while moving at a constant pitch, whereas the belt causes a deviation due to meandering, resulting in a pitch deviation between ink dots, and The image becomes an image with a high density of dots and the quality is degraded.

The present invention solves this problem, and an object thereof is to provide a belt meandering preventing device with a simple structure.

[0009]

According to the belt conveying device of the present invention, an endless belt is stretched by a driving roller axially supported by a frame and a driven roller movably supported in the belt stretching direction. The driven roller is axially movably supported, and is interposed between the endless belt-shaped belt and the driven roller to release the engagement between the endless belt-shaped belt and the driven roller, and the driven roller. And a means for moving to a predetermined position.

Further, the means for releasing the engagement between the endless belt and the driven roller is operated by a drive signal.

Further, the means for releasing the engagement between the endless belt and the driven roller is operated by axial movement of the driven roller.

Further, the driven roller is a roller separate from the tension roller.

Further, the driven roller is the same roller as the tension roller.

Further, in an intermediate transfer type ink jet recording apparatus for transferring to a recording medium to obtain an ink image, a recording head for selectively ejecting ink droplets to form an ink image on the transfer medium, and a gap between the recording head and the recording head. Confront through
A transfer image forming unit having an endless belt-shaped transfer medium rotatably supported by a plurality of rollers; a heating unit located around the transfer medium for heating and forming an ink image on the transfer medium; A paper feeding unit located downstream of the recording head for feeding the recording medium; a transfer roller located downstream of the heating unit for transferring the ink image on the transfer medium onto the recording medium fed from the paper feeding unit; And a transfer unit configured to discharge the recorded recording medium, wherein the transfer image forming unit is configured by the belt conveying device according to claim 1.

Further, the transfer image forming section is characterized in that the means for releasing the engagement between the endless belt and the driven roller is operated at a time other than the image recording step and the transfer step.

[0016]

According to the above construction, meandering of the belt can be prevented,
If the above mechanism is mounted on an intermediate transfer type ink jet recording device, a high-quality image without image distortion at the time of writing an ink image can be obtained.

[0017]

The present invention will be described in detail below with reference to examples.

FIG. 1 is a plan view of the first embodiment of the belt conveying device, and FIG. 2 is a side view showing the belt and the roller portion viewed from the P arrow direction in FIG. The belt 1 is rotatably stretched by a drive roller 2 rotatably supported by a frame 20, a tension roller 13 movably supported in a belt tension direction, and a driven roller 5, and the driven roller 5 is Is rotatably supported in the axial direction. A spring 14 tensions the belt 1 via a tensioning roller 13.

A flange 2a and a gear 2b for restricting the width direction of the belt 1 are fixedly provided at both ends of the drive roller 2, and the gear 2a is engaged with the motor 3 via a gear 4. A separation plate 6 is rotatably supported on the same axis of the driven roller 5, and the radius of the rotating portion 6b of the separation plate 6 is larger than the radius of the driven roller 5. A gear 6a is fixedly provided at both ends of the separation plate 6, and is connected to a motor 11 via a gear 9 and a motor gear 10.

FIGS. 3A and 3B are detailed sectional views of the driven roller section taken in the direction of arrow P in FIG.

The elastic lever 7 and sensor 8 are
It is fixed to the frame 20 and is in a position where it comes into contact with the sensor 8 when one end 7a of the lever 7 is bent. Lever 1
Reference numeral 2 is rotatably attached to a shaft fulcrum 12a fixed to the frame 20. A convex cam 9 is provided on the side surface of the gear 9.
a is fixed, and abuts on one end of the lever 12 by rotating.

Next, the operation will be described. 1 and 2, the drive roller 2 is rotated by the power of the drive motor 3 via the gear 4 and the gear 2b, and the belt 1 is rotated in the arrow a direction. At this time, the belt 1 cannot absorb the dimensional error of each related component, the mounting error of the roller member, the imbalance of the belt tension, the nonuniformity of the belt circumferential length, etc. by the deformation of the belt itself. A force F that tends to be biased in the direction perpendicular to the traveling direction is generated. (The direction of the force F may be the opposite direction, but for the sake of convenience, the direction of the arrow F in the figure)
The movement of the belt 1 in the width direction is restricted by the flange end portion 2a provided on the drive roller 2, and the deviation of the belt on the drive roller 2 does not occur.

On the other hand, the force F that the belt 1 is biased is transmitted to the driven roller 5 via the belt 1. Here, a reaction force in the direction opposite to the force F acts on the driven roller 5, but since the driven roller 5 is axially supported so as to be movable in the axial direction, the driven roller 5 moves in the axial direction of arrow b while rotating.

FIG. 3 shows a state in which the driven roller 5 moves. In FIG. 3A, the driven roller 5 in the predetermined position moves in the direction of the arrow b as shown in FIG. 3B, and the tip portion 5b of the driven roller 5 pushes the lever 7 and the lever 12. When one end of the lever 7 comes into contact with the detector 8, an input signal is input to a control circuit (not shown), and the amount of movement of the driven roller 5 is detected.

Next, referring to FIG. 2, when the motor 11 is driven by the drive signal output from the control circuit, the separating plate 6 is passed through the gear 10, the gear 9 and the gear 6a.
Rotates in the direction of arrow c.

Although the peripheral speed of the belt 1 and the speed of the rotating portion 6b of the separating plate 6 are kept at substantially the same speed, they are rotated. However, since the radius of the rotating portion 6b is larger than the radius of the driven roller 5, the separating plate 6 is gradually moved. When the belt 1 is rotated while being separated from the driven roller 5, and the rotating portion 6b passes the position of the rotating portion 6c shown by the substantially broken line, the engagement between the belt 1 and the driven roller 5 is released, and the driven roller 5 is The force F generated in 1 is released. Further, the separating plate 6 rotates and returns to the original position. During this time, the belt tension roller 13 is axially supported so as to be movable in the belt tension direction, absorbs the fluctuation of the belt circumferential length by the separating plate 6 during rotation, and is shown by a broken line against the spring force of the spring 13. Move to the position and return to the original position.

On the other hand, as shown in FIG. 3 (b), the lever 12 pushed and rotated by the shaft of the driven roller 5 comes into contact with the convex cam 9a by the rotation of the gear 9 and is pushed back to rotate in the direction of arrow d. Then, the driven roller 5 is pushed back to a predetermined position (see FIG. 3).
(State of (a)).

As described above, the separation plate 6 operated by the drive signal from the control circuit releases the engagement between the belt 1 and the driven roller 5 to eliminate the biasing force F generated on the belt 1 to cause the meandering. To prevent.

The second embodiment of the present invention will be described with reference to FIG. FIGS. 6A and 6B are detailed cross-sectional views of the driven roller 5, the separation plate 6 and the drive section thereof.

The configuration and operation will be described. A bevel gear 5a is fixed to both ends of the driven roller 5. A convex cam 9a is provided on the side surface of the rotatable gear 9 supported by the frame 20 and a bevel gear 9b is provided on the other surface.
Further, the gear 9 is a gear 6a provided at both ends of the separation plate 6.
Always rotatably engaged with.

When the reaction force of the force F of the belt 1 is generated as in the first embodiment, the driven roller 5 is rotated and moved in the direction of arrow b as shown in FIG. 6 (b). At this time, the bevel gear 5a and the bevel gear 9b are engaged with each other, and the separating plate 6 is rotated via the gear 9 by the rotational force of the driven roller 5 transmitted by the belt.

Thereafter, the separating plate 6 is operated similarly to the operation of the first embodiment.
Thus, the engagement between the belt 1 and the driven roller 5 is released, the biasing force F generated in the belt 1 is eliminated, and the meandering is prevented. On the other hand, the lever 12 is the shaft tip 5b of the driven roller 5.
While the separation plate 6 is being operated, the convex cam 9a on the side surface of the gear 9 engages with the other end of the lever 12 by the rotation of the gear 9 during the operation of the separating plate 6, and the lever 12 rotates in the direction of arrow c to move the driven roller 5 Push it back in place. The rotational force of the separation plate 6 is obtained through the gear 9 by the rotational force of the driven roller 5 at the start of rotation, and when the separation plate 6 releases the engagement between the belt 1 and the driven roller 5, It is rotated by a friction transmission force of 1.

A third embodiment of the present invention will be described with reference to FIG.

Inclined portions 5c are fixedly provided at both ends of the driven roller 5. A convex cam 9a is provided on the side surface of the rotatable gear 9 supported by the frame 20 and an inclined portion 9c is provided on the other surface.
Is provided. The gear 9 is always rotatably engaged with the gears 6a provided at both ends of the separation plate 6.

Similarly to the second embodiment, the driven roller 5 rotates and moves in the direction of the arrow b, and the slant surface portion 5c and the slant surface portion 9c.
Contact with each other, and further, the gear 9 is rotated by the frictional force due to the pressing of the driven roller 5, and the separation plate 6 is rotated via the gear 9 and the gear 6a.

The subsequent structure and operation are the same as those in the second embodiment, and the description thereof will be omitted.

The second and third embodiments are examples in which the operation of the separation plate 6 can be activated only by the movement of the driven roller 5 in the axial direction.

The configuration and operation of the fourth embodiment of the present invention will be described with reference to FIGS.

In FIG. 4, a belt 1 is stretched around a frame 20 by a spring 22 with a driving roller 2 axially supported and a driven roller 5 axially supported so as to be movable in the stretching direction of the belt. The driven roller 5 is axially supported so as to be movable in the axial direction. A separation plate 6 is rotatably supported on the same axis of the driven roller 5. On the same axis as the driven roller 5,
The separation plate 6 is rotatably supported.

In the case of this embodiment, the driven roller and the tension roller are integrated as compared with the first embodiment, but the operation is the same as in the first or second embodiment.
The separation plate 6 releases the engagement between the belt 1 and the driven roller 5, eliminates the biasing force F generated in the belt 1 and prevents the meandering, and therefore detailed description thereof will be omitted.

FIG. 8 is a side view showing an embodiment of an intermediate transfer type ink jet recording apparatus equipped with the mechanism according to the present invention.

The configuration and operation will be described. The main configuration of this apparatus is that a recording head 33 that selectively ejects ink droplets to form an ink image on a transfer medium faces a recording head 33 with a gap and is rotated by a plurality of rollers. A transfer image forming portion 32 having an endless belt-shaped transfer medium 1 (hereinafter referred to as a belt) which is rotatably supported, and a heating portion which is located around the belt 1 and heat-film-forms an ink image on the belt 1. 34, and a paper feed unit 3 located downstream of the recording head 33 and for feeding the recording medium 30 (hereinafter referred to as recording paper)
1, a transfer roller 35 located further downstream, which presses and transfers the ink image on the belt 1 onto the recording paper 30 fed from the paper supply unit 31, and a discharge unit 36 which discharges the transferred recording paper 30. And an ink supply unit 37 that supplies ink to the recording head 1.

In the recording process for forming an image, first, the belt 1 as a transfer medium is rotated in the direction of arrow a by driving a motor (not shown). The recording head 33 writes an ink image for one page on the belt 1 while moving in a direction parallel to the axis of the driving roller 2 by a predetermined amount in synchronization with the rotation of the belt 1. In this embodiment, the belt rotates 1 times with 16 rotations.
Write the page image. Further, during the writing, the ink droplets of the image formed on the belt 1 are heated by the heating unit 34 while being dried and formed into a film to improve the transferability. Next, in the transfer step, after the image for one page is written, the recording paper 30 sent from the paper feeding unit 31 to a predetermined position in synchronization with the image position is transferred from the back side while being pressed by the transfer roller 35. The recording paper 30 moves in the belt traveling direction and is discharged by the paper discharge unit 36.

The detailed operation for preventing the meandering of the transfer image forming portion 32 including the belt 1 in this embodiment is the same as that in the first to fourth embodiments, and therefore will be omitted. If the separation plate 6 for releasing the engagement between the belt 1 of the separation plate 6 and the driven roller 6 is operated at a time other than the image recording process and the transfer process, the belt traveling by the rotation of the separation plate 6 is performed. Direction, there is no adverse effect such as fluctuation of belt tension, and since an ink image can be written in a state where the belt does not meander, a high-quality image with no image distortion can be obtained.

[0045]

As described above, according to the present invention, as a belt conveying device, belt meandering can be prevented, and recording paper can be accurately conveyed. In addition, since there is no need to make any mechanical or electrical adjustments to the force that tries to meander in the belt width direction, it is difficult to make initial assembly adjustments.
No need for maintenance. Further, in the intermediate transfer type ink jet recording apparatus equipped with the mechanism of claim 1, a high-quality image with less image distortion can be obtained due to the improvement of the positional accuracy of the belt as the transfer medium, and the structure is simple and simple. It is possible to provide a high-performance inkjet recording apparatus that can be made compact and compact, and can be made small in size as a whole main unit.

[Brief description of drawings]

FIG. 1 is a diagram showing a plan view of a belt conveying device according to a first embodiment of the present invention.

FIG. 2 is a side view of the belt conveying device according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a driven roller 5 according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a plan view of a fourth embodiment.

FIG. 5 is a diagram showing a side view of a fourth embodiment.

FIG. 6 is a diagram showing a second embodiment.

FIG. 7 is a diagram showing a third embodiment.

FIG. 8 is a diagram showing a schematic view of an intermediate transfer type inkjet recording apparatus according to the present invention.

FIG. 9 is a diagram showing a conventional example.

[Explanation of symbols]

 1: Belt 2: Drive roller 3: Motors 2b, 4, 6a, 9, 10: Gear 5: Driven roller 6: Separation plate 13: Tension roller 20: Frame 30: Recording paper 31: Paper feed section 32: Belt transport Device 33: Recording head 34: Heating unit 35: Transfer roller 36: Paper ejection unit 37: Ink supply unit 38: Fan

Claims (7)

[Claims] 1. An endless belt is stretched by a drive roller axially supported by a frame and a driven roller movably supported in a belt tensioning direction, and the driven roller is axially movably supported in the belt. And means for interposing the endless belt-shaped belt and the driven roller to release the engagement between the endless belt-shaped belt and the driven roller, and means for moving the driven roller to a predetermined position. A belt transport device characterized in that 2. The belt conveyor according to claim 1, wherein the means for releasing the engagement between the endless belt and the driven roller is activated by a drive signal. 3. The belt conveying device according to claim 1, wherein the means for releasing the engagement between the endless belt and the driven roller is operated by axial movement of the driven roller. 4. The belt conveying device according to claim 1, wherein the driven roller is a roller separate from the tension roller. 5. The belt conveyor according to claim 1, wherein the driven roller is the same roller as the tension roller. 6. An intermediate transfer type ink jet recording apparatus for transferring an ink image onto a recording medium to selectively eject ink droplets to form an ink image on the transfer medium, and a gap between the recording head and the recording head. A transfer image forming portion having an endless belt-shaped transfer medium that is rotatably supported by a plurality of rollers, and an ink image on the transfer medium that is located around the transfer medium. A heating unit, a paper feeding unit located downstream of the recording head for feeding the recording medium, and a printing unit located downstream of the heating unit for feeding the ink image on the transfer medium onto the recording medium fed from the paper feeding unit. An intermediate transfer type ink jet recording apparatus, comprising: a transfer roller that discharges the transferred recording medium; and a discharge unit that discharges the transferred recording medium. 7. The timing for activating the means for releasing the engagement between the endless belt and the driven roller in the transfer image forming section is operated at a time other than the image recording step and the transfer step. 7. The intermediate transfer type inkjet recording device described in 7.