JPH04144850A - Endless belt carrying device - Google Patents

Abstract

PURPOSE:To minimize the changing quantity of the alignment of a steering roll and miniaturize the endless belt carrying device by providing an auxiliary roll which curves the belt carrying path between the steering roll and the roll next to the steering roll in the opposite side of the belt near the steering roll. CONSTITUTION:An auxiliary roll 5 is rotatably supported by a device frame supporting driven rolls 31 and 32 and drive roll 2 and is brought into contact with the outer peripheral surface of a belt 1 between the roll 31 and a steering roll 4 and is arranged so as to curve the belt carrying path between the rolls. In addition, the belt 1 is moved in the width direction by the change of the alignment of the roll 4 at the speed according to the quantity of the change. Since the auxiliary roll 5 is thus arranged, the winding angle of the belt 1 to the roll 4 can be set largely as a result, the belt 1 can react quicker and more smooth against the change of the alignment of the roll 4. Even the small changing quantity of alignment, therefore, makes it possible to properly control the width directional movement of the belt 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a conveying device for rotating an endless belt, and more particularly to an improvement in a conveying device having means for preventing meandering of the belt.

[Prior Art] FIG. 7 shows an example of a color electrophotographic copying machine that uses an endless belt to convey recording sheets.

Specifically, a driving roll 2 and a plurality of rolls 31, 32, . While the endless belt 1 (hereinafter referred to as the belt) is stretched between ..., four sets of visible images are formed to form toner images (visible images) corresponding to each color of cyan, magenta, yellow, and black using an electrophotographic process. Forming unit 9,9. ... are arranged on one side of the endless belt 1 at appropriate intervals. Each visible image forming unit 9,9. ... is a charger 92 and a latent image writing means 93 around an electrostatic latent image carrier 91 such as a photoreceptor drum.
, a developing device 94 and a cleaner 95 are arranged,
A toner image corresponding to the image information of each color is formed on the electrostatic latent image carrier 91, and the toner image is pressure-transferred onto the recording sheet 7 conveyed by the belt 1.

Therefore, the recording seed door carried out from the supply tray 7a is held by the belt 1 at a predetermined timing, and then as the belt 1 advances, each visible image forming unit 9, 9...・・・
・The toner image of each color is transferred sequentially from ・ to a full-color toner image. Then, the recording sheet 7 on which the toner image has been transferred is peeled off from the belt 1 and sent out onto the discharge tray 7b via the fixing device 8, thereby completing the formation of the color recorded image.

In FIG. 7, reference numeral 71 denotes a tacking roll that attracts the recording sheet 7 to the belt 1 at a predetermined timing;
6 is a pressure roll for nipping the recording sheet onto the electrostatic latent image carrier 91; 72 is a cleaner for removing dirt from the surface of the belt 1; and 10 is a tension adjustment roll for applying a constant tension to the belt. be.

In this image forming method in which multiple toner images are multiple-transferred onto a recording sheet, the premise of forming a high-quality recorded image without color shift is that the recording sheet is conveyed accurately along a predetermined path. is important. Therefore, it is necessary for the belt that conveys the recording sheet to not move in the width direction when rotating.

However, it is virtually impossible to completely prevent movement of the belt in the width direction due to imperfections in the forming of the belt and each roll, the parallelism of the rolls on which the belt is stretched, and the like.

Therefore, conventional belt conveying devices are provided with a control mechanism that corrects the generated movement of the belt in the width direction and suppresses the amount of movement within a predetermined tolerance.

As an example, an active steering system is known in which the alignment of rolls supporting the belt is appropriately changed and the belt is actively moved in the width direction to correct belt meandering.

Specifically, the − roll (for example, roll 4 in FIG. 7) is a steering roll whose alignment can be changed, and as shown in FIG. 5(A)→FIG. 5(B), one end of roll 4 is By giving the roll 4 an angle θ corresponding to the amount of correction of the belt 1 using the fulcrum as the fulcrum, or as shown in FIG.
A) → As shown in FIG. 5(C), the belt 1 is guided to a predetermined conveyance path by giving an angle θ using the center of the roll as a fulcrum.

[Problem to be solved by the invention] By the way, in an endless belt conveying device using such an active steering method, it is important to minimize changes in steering roll alignment in order to downsize the device. In this case as well, the belt must react sensitively to this and move smoothly on the roll.

Also, reducing the amount of change in alignment is important from the perspective of suppressing twisting of the belt and ensuring flatness of the belt between rolls. When an image is transferred to a recording sheet that has been used, this condition is absolutely required from the viewpoint of improving the image quality.

However, in conventional devices where the belt is simply stretched around the steering roll, the belt has poor responsiveness and followability to changes in the alignment of the steering roll, and the belt cannot be adjusted to the specified position without changing the alignment more than necessary. It was not possible to quickly and smoothly guide the conveyance route.

The present invention was made in view of these problems, and its purpose is to provide an endless belt conveyor that can minimize the amount of change in the seven alignments of the steering roll and achieve miniaturization of the device. The goal is to provide equipment.

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present application have conducted extensive studies and experiments, and have found that when the winding angle of the belt around the steering roll is increased, the belt changes in response to changes in the alignment of the roll. It was found that the reaction was quick and smooth. By utilizing this phenomenon, they were able to solve the above problem.

That is, the endless belt conveying device of the present invention includes a plurality of rolls arranged in parallel, and a steering roll whose arrangement angle can be changed as appropriate with respect to these rolls,
In an endless belt conveying device that conveys an endless belt stretched across a group of rolls while controlling the movement of the belt in the width direction, there is a steering wheel located near the steering roll on the opposite side of the steering roll with the belt in between. It is characterized by the provision of an auxiliary roll that bends the belt conveyance path between the roll and another roll adjacent thereto.

Such technical means can be applied to various types of endless belt conveying devices, and the belts used may be made of various materials and have various structures. For example, a semiconductive electrostatic adsorption belt that conveys recording sheets such as paper,
It can be applied to ink recording media in transfer recording devices, belt-shaped photoreceptors used in electrophotographic processes, and the like.

In addition, as for the above-mentioned auxiliary roll, if the winding angle of the belt around the steering roll in the state where the roll is arranged is larger than the winding angle when the roll is removed, the arrangement with respect to the steering roll can be appropriately designed. You can change it.

[Function] By arranging the auxiliary roll according to the above technical means and bending the belt conveyance path between the steering roll and other rolls adjacent thereto, the winding angle of the belt around the steering roll is increased, Immediate response and followability of the belt when changing alignment are improved.

Furthermore, since the angle at which the belt wraps around the steering roll becomes larger, the torque transmission limit between the belt and the roll becomes higher, and slippage between the two is prevented.

[Example] Hereinafter, the endless belt conveying device of the present invention will be explained in detail based on the accompanying drawings.

FIG. 1 shows a schematic configuration of a first embodiment of the present invention, which can be applied to the recording sheet conveying mechanism of the color image forming apparatus shown in FIG.

Specifically, a drive roll 2 to which a motor H is connected;
Driven rolls 31 and 32 that rotate freely following the belt 1
, a steering roll 4 whose alignment can be adjusted appropriately with respect to these rolls, and this steering roll 4
and the auxiliary roll 5 disposed between the driven roll 31 and the driven roll 31.
The endless belt 1 is conveyed under tension by a group of these rolls.

The belt 1 is an annular body that holds and conveys the recording sheet by electrostatic attraction, and as shown in FIG. 2, it has a two-layer structure consisting of an insulating inner layer 11 and a semiconductive outer layer 12. , a plurality of electrodes 13 are embedded in parallel at regular intervals between each layer 11, 12. Further, the electrodes 13 are exposed on the inner layer 11 at the ends in the width direction of the belt, and a plurality of brush power feeders (not shown) can be brought into sliding contact with the exposed portions 14 to energize each electrode 13. It has become. Therefore, by alternately applying a low voltage and a high voltage to the arranged brush power feeders, an electric field is formed between the electrodes 13, 13, etc., and the recording sheet can be electrostatically attracted to the surface of the outer layer 12. It is possible.

Between the steering roll 4 and the driving roll 2 is a sheet conveyance area where the recording sheet is attracted to the belt 1 and conveyed, and in this area, movement of the stretched belt 1 in the width direction is detected. A sensor (not shown) is provided. In addition, the steering roll 4 is provided with an angle adjustment means (not shown) that changes the alignment of the rotating shaft according to the detected value of the sensor, and close-loop control is used to adjust the angle between the steering roll 4 and the drive roll 2. The amount of movement of the stretched belt 1 in the width direction is controlled within a predetermined tolerance.

Note that numerals 33 and 34 indicate the belt 1 in the sheet conveyance area.
This is a support roll for ensuring the flatness of the belt 1, and prevents twisting of the belt 1 caused by changes in the alignment of the steering roll 4 from propagating to the sheet conveying area.

The auxiliary roll 5 is rotatably supported by a device frame (not shown) that supports the driven rolls 31 and 32 and the drive roll 2, and a belt is connected between the driven roll 31 and the steering roll 4. 1, and is arranged so as to bend the belt conveyance path between these rolls.

In the endless belt conveying device of this embodiment configured in this way, as in the conventional active steering system in which the driver is seated, by changing the alignment of the steering roll 4, the belt 1 is adjusted according to the amount of change in alignment. It moves in the width direction on the roll 4 at high speed.

FIG. 6 shows the relationship between the amount of change in the alignment of the steering roll 4 and the moving speed of the belt 1 for the endless belt conveying device of this embodiment provided with the auxiliary roll 5 and a conventional device without the auxiliary roll 5 (conventional example). This shows the results of an investigation. As is clear from this figure, the moving speed of the belt in this embodiment is improved compared to the conventional example.

The winding angle of the belt around the steering roll is 165° in this embodiment and 138° in the conventional example.

As described above, in this embodiment, by arranging the auxiliary roll 5 as described above, the winding angle of the belt 1 around the steering roll 4 can be set large, and the belt 1 can be adjusted accordingly when the alignment of the steering roll 4 is changed. The reaction becomes quick and smooth.

Therefore, even if the amount of alignment change is small, the belt 1
It is possible to properly control the movement in the width direction.

FIG. 3 shows the main part of a second embodiment of the present invention.

In this embodiment, the rotation shaft of the auxiliary roll 5 is connected to the rotation shaft of the steering roll 4 by a connecting member 6. Therefore, the auxiliary roll 5 moves together with the steering roll 4 as the alignment changes, and the parallelism between the two rolls 4 and 5 is always maintained.

In the device of the present invention, even when the support form of the auxiliary roll 5 is changed in this way, the reaction of the belt 1 to the change in the alignment of the steering roll 4 is quick and as in the first embodiment. It becomes smooth.

FIG. 4 shows a third embodiment of the present invention, in which a steering roll 4 is arranged between a pair of driven rolls 31, 32.

In this way, when the steering roll 4 is arranged on a straight portion of the belt conveyance path to control the meandering of the belt 1, the winding angle of the belt 1 with respect to the steering roll 4 becomes small, so that the belt 1 is The reaction is bound to be slow.

Therefore, in the third embodiment, the auxiliary rolls 5 are arranged on both sides of the steering roll 4 so that the winding angle of the belt 1 is sufficiently large.

In FIGS. 3 and 4, the same members as those in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted.

In addition, when using the apparatus shown in the first to third embodiments, for example, as shown in FIG. Although it is necessary to provide various auxiliary equipment around the belt depending on the manner of use, such as the provision of adjustment rolls, only the minimum necessary configuration has been described here for the sake of simplification.

[Effects of the Invention] As explained above, according to the endless belt conveying device of the present invention, the winding angle of the belt around the steering roll is increased, and the immediate response and followability of the belt when changing the alignment of the steering roll are improved. Therefore, the belt can be efficiently corrected even if the amount of change in alignment is small, and the apparatus can be made smaller.

In addition, the angle at which the belt wraps around the steering roll increases, preventing slippage between the two.
In this respect as well, it is possible to efficiently correct the belt.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing a first embodiment of the endless belt conveying device of the present invention, FIG. 2 is a sectional view showing the endless belt according to the first embodiment, and FIG. 3 is a second embodiment of the present invention. 4 is a diagram showing the outline of the third embodiment of the present invention, FIGS. 5(A) to 5(C) are diagrams explaining the operation of the active steering system, and FIG. 6 is a diagram showing the outline of the third embodiment of the present invention. FIG. 7 is a graph showing the relationship between the roll alignment change amount and the belt tossing speed, and FIG. 7 is a diagram schematically showing a color image forming apparatus to which the present invention can be applied. [Description of symbols] 1: Endless belt 2 Drive roll 4 Steering roll 5: Auxiliary roll 6: Connecting member H: Motor

Claims (1)

[Claims] It is equipped with a plurality of rolls arranged in parallel and a steering roll whose arrangement angle can be changed as appropriate with respect to these rolls, and the endless belt stretched across these rolls is controlled to move in the width direction. In the endless belt conveyance device that conveys the above-mentioned steering roll, there is an auxiliary member located on the opposite side of the steering roll with the belt in between, which bends the belt conveyance path between the steering roll and another roll adjacent thereto. An endless belt conveyance device characterized by being equipped with rolls.