JPH05165385A - Endless belt drive - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to an endless belt driving device, and an object thereof is to prevent meandering of a conveyor belt and to make the conveyor speed uniform at both ends in the width direction of the conveyor belt. A meandering detection means (60) detects a widthwise displacement of the conveyor belt due to meandering. Roller moving means (4
0) is provided on any one of the plurality of rollers, and moves the roller in the rotation axis direction. The meandering prevention control means (61) controls the movement of the roller of the roller movement means (40) so as to cancel the displacement of the conveyor belt detected by the meandering detection means (60).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt driving device, and more particularly to a device for driving an endless belt of an image recording device such as an electrophotographic device.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a general 4-drum type electrophotographic image device. In the figure, reference numeral 10 denotes a yellow image forming portion, which includes a photosensitive drum 11, a charging device 12, an exposing device 13, a developing device 14, a transfer device 15, and a cleaner 16. The image forming units 17, 18, and 19 for magenta, cyan, and black, which have the same configuration as the image forming unit 10, are arranged in a line.

The recording paper 24 sent by the feeding rollers 22 and 23 is conveyed to the rollers 25, 26 and 27 by the conveyor belt 2.
The endless belt driving device wound around 8 sends the color toner images to the image forming units 10 and 17 to 19 in order of yellow, magenta, cyan, and black. After that, the recording paper 24 is sent to the fixing device 30, and the color toner image is fixed to the recording paper 24 by heat.

If the conveyor belt meanders when the recording paper 24 is fed by the above-mentioned endless belt device, a color superposition position shift occurs when the color toner images are superposed and transferred.

In order to prevent this, the conventional endless belt driving device prevents the meandering by swinging the rotating shaft of the roller 26 in accordance with the meandering of the conveyor belt 28, as described in JP-A-60-171906. is doing.

[0006]

However, when the rotation shaft of the roller 26 is swung, the conveying speed is different at both ends of the width and direction of the conveying belt 28, and when the color toner image is transferred, the conveying speed is high. There is a problem in that the color toner image transferred on the end side is slower than the end side and the image is distorted.

The present invention has been made in view of the above points,
An object of the present invention is to provide an endless belt drive device which prevents meandering of the conveyor belt and has the same conveyor speed at both ends in the width direction of the conveyor belt.

[0008]

SUMMARY OF THE INVENTION An endless belt drive device of the present invention is an endless belt drive device for driving a loop-shaped conveyor belt wound around a plurality of rollers by rotating a drive roller among the plurality of rollers. A meandering detecting means for detecting a displacement in the width direction due to the meandering of the conveyor belt, a roller moving means provided on any one of the plurality of rollers, and moving the roller in the rotation axis direction, and a meandering detecting means. And a meandering prevention control means for controlling the movement of the roller of the roller movement means so as to cancel the displacement of the conveyor belt detected in.

[0009]

According to the present invention, the widthwise displacement due to the meandering of the conveyor belt is detected, and the roller around which the conveyor belt is wound is moved in the direction of the rotation axis of the roller so as to cancel the displacement, so that the meandering can be prevented. Further, since the rollers are moved in the rotation axis direction, the conveyance speed is the same at both ends of the conveyance belt in the width direction.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a block diagram of an embodiment of the device of the present invention. In the figure, those parts which are the same as those corresponding parts in FIG. 4 are designated by the same reference numerals, and a description thereof will be omitted.

In FIG. 1, the conveyor belt 28 is a roller 2
It is wound around 6, 27 and 40. The roller 26 is rotationally driven by the belt driving motor 41, and the conveyor belt 2
8 is carried. The roller 27 applies tension so that the conveyor belt 28 does not sag.

The roller 40 guides the conveyor belt 27, and its detailed cross section is shown in FIG. In FIG. 2A, a screw thread is formed on the peripheral surface of the rotary shaft 45 of the roller 40, and the rotary shaft 45 is rotationally driven by a ball screw driving motor 46. The rotary shaft 45 has a collar portion 47 at both ends.
A ball screw mechanism is configured by being threadedly inserted into a cylindrical female screw portion 49 to which 48 is fixed. The flange portions 47 and 48 are fixed to the substrate 52 by the guide members 50 and 51, and
5 is regulated so as not to rotate due to rotation. Bearings 53 and 54 are provided on the outer peripheries of both ends of the female threaded portion 49, and a cylindrical rotating member 55 as shown in FIG. It is wound around the outer periphery of the rotating member 55.

Therefore, when the ball screw driving motor 46 is driven to rotate the rotary shaft 45 in the clockwise direction (or counterclockwise direction), the female screw portion 49 and the rotary member 55 move in the arrow a direction (b direction). .

Returning to FIG. 1, the conveyor belt 28 will be described.
The laser discrimination sensor 6 at a position corresponding to one end in the width direction of the
0 is provided. The laser discrimination sensor 60 is the generation unit 6
The laser beam emitted from 0a is irradiated to the end portion of the conveyor belt 28 and is received by the light receiving portion 60b facing the light emitting portion 60a. When the conveyor belt 28 meanders, the conveyor belt 28
The light-shielding amount of the laser light at the end of the changes the output voltage of the light receiving unit 60b. For example, the output voltage is 5 V when the light blocking rate by the transport belt 28 is 0%, the output voltage is 3 V when the light blocking rate is 50%, and the output voltage is 1 V when the light blocking rate is 100%. The light receiving section 60 of the laser discrimination sensor 60
The output signal of b is supplied to the meandering prevention control circuit 61. As shown in FIG. 3, the meandering prevention control circuit 61 includes an AD converter 63, a microprocessor (MPV) 64, and a drive circuit 65. The output signal of the light receiving unit 60b is supplied from the terminal 62 to the AD converter 63, where it is digitized and supplied to the MPU 64.

The MPU 64, as shown in FIG.
When the output voltage of the light receiving unit 60b is higher than (or lower than) 3V at 1, the conveyor belt 28 moves in the direction of the arrow b (or the direction of a) and only the amount corresponding to the difference between the output voltage and 3V. When it is determined that the vehicle is displaced and meandering, a command value for canceling the meandering is calculated and supplied to the drive circuit 65 in step S2, and the drive circuit 6 is operated according to the command value in step S3.
Reference numeral 5 drives the ball screw driving motor 46 to rotate.
As a result, the rotating member 55 of the roller 40 moves the conveyor belt 2
According to the meandering of No. 8, the meandering of the conveyor belt 28 is canceled by moving in the arrow a direction or the b direction.

In this case, since the roller 40 moves in the width direction orthogonal to the conveyance direction of the conveyor belt 28, the conveyance speed is the same at both ends in the width direction of the conveyor belt 28, and when the color toner image is transferred, the image is transferred. There is no distortion.

By the way, the apparatus of the present invention is not limited to the four-drum type electrophotographic image apparatus, but may be suitably applied to a one-drum type electrophotographic image apparatus as shown in FIG.

In FIG. 5, 71 to 74 are Y, M, C,
BK developing devices, 75 exposure devices, 76 photosensitive drums,
77 and 78 are cleaners, and the color toner images transferred onto the photosensitive drum 76 are transferred onto the intermediate belt 80 in an overlapping manner.
The recording sheet 81 is transferred from the intermediate belt 80 to the recording sheet 81, and the recording sheet 81 is fixed by the fixing device 82. In this embodiment, for example, the roller 83 of the intermediate belt 80 is provided with a ball screw mechanism as shown in FIG. 2, the meandering of the intermediate belt 80 is detected, and the roller 83 is moved in its axial direction to prevent the intermediate belt 80 from meandering.

As described above, the widthwise displacement due to the meandering of the conveyor belt 28 is detected, and the roller 40 around which the conveyor belt 28 is wound is moved in the direction of the rotation axis of the roller so as to cancel the above displacement. This can be prevented, and since the roller 40 is moved in the rotation axis direction, the conveying speed at the widthwise ends of the conveying belt 28 is the same.

In the present embodiment, an example in which a discrimination sensor using laser light is used for detecting meandering has been described, but the present invention is not limited to this, and changes in electrostatic capacity and magnetic field may be detected. The detection may be performed by utilizing, and various known detection methods can be used.

[0021]

As described above, according to the endless belt driving device of the present invention, meandering of the conveyor belt is prevented, and the conveyor speed is the same at both ends in the width direction of the conveyor belt, so that the image recording apparatus such as an electrophotographic apparatus. When used for, it is possible to prevent distortion of the image and obtain a high quality image, which is extremely useful in practice.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a device of the present invention.

FIG. 2 is a detailed configuration diagram of a ball screw mechanism.

FIG. 3 is a block diagram of a meandering prevention control circuit.

FIG. 4 is a processing flowchart executed by a meandering prevention control circuit.

FIG. 5 is a configuration diagram of an electrophotographic image recording apparatus.

FIG. 6 is a configuration diagram of an electrophotographic image recording apparatus.

[Explanation of symbols]

 26, 27, 40 roller 28 conveyor belt 60 laser discrimination sensor 61 meandering prevention control circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Kato 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (1)

[Claims] 1. An endless belt driving device for driving a loop-shaped conveyor belt wound around a plurality of rollers by rotating a driving roller of the plurality of rollers, wherein the conveyor belt is displaced in the width direction due to meandering. And a meandering detection means (60) for detecting, and provided on any one of the plurality of rollers,
Roller moving means (40) for moving the roller in its rotation axis direction, and meandering means for controlling the movement of the roller of the roller moving means (40) so as to cancel the displacement of the conveyor belt detected by the meandering detecting means (60). An endless belt driving device, comprising: prevention control means (61).