JPH04133927A - Endless belt carrying device - Google Patents

Abstract

PURPOSE:To keep the movement in a cross direction of a belt within a fixed carrying course by slide-rotatably attaching a supporting arm to a U-shaped roll suspendedly holding member, and sliding the supporting arm on a belt cross-directional displacement signal. CONSTITUTION:An endless belt 1 is extendingly engaged between a driving roll 2 and a steering roll 4. The steering roll 4 is rotatably beared by both the ends of the U-shaped holding member 31 of a roll suspending means 3, and the holding member 31 is movably beared by a supporting arm 32 through a connecting point 33. The supporting arm 32 can slide in the axial direction of the roll 4, and the arm length of the holding member 31 on the right and left sides of the connecting point 33 can be properly changed. When a detecting means 5 detects the deviation of a belt 1, a driving means 6 slides the supporting arm 32 according to the quantity of deviation, and the length of the holding member 31 on its both sides therefore changes to displace the roll 4 for preventing the deviation of the belt 1. Thus the carrying course of the belt 1 can be fixedly maintained.

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 bell 1. .

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

Specifically, a plurality of rolls 21, 22 . ...and endless belt 1
(hereinafter referred to as Bell 1~), four sets of visible images (visible images) corresponding to cyan, magenta, yellow, and black are formed using an electrophotographic process. Image forming units 1-9, 9, . . . are arranged at appropriate intervals on one side of the endless belt 1. Each of the visual image forming units 1 to 9, 9, . A charger 92, a latent image adjusting means 93, a developing device 94, and a creep 95 are arranged around an electrostatic latent image carrier 91 such as a photoreceptor drum, and one henna image is produced according to image information of each color. is formed on the electrostatic latent image carrier 91, and the tonneau image is pressure-transferred onto the recording sheet 8 conveyed by the belt 1.

Therefore, the recording sheet 8 carried out from the supply tray 8a 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 8 on which the toner image has been transferred is peeled off from the belt 1 and sent out onto the discharge tray 8b via the fixing device 10, thereby completing the formation of the color recorded image.

In FIG. 4, reference numeral 81 denotes a tacking roll that attracts the recording sheet 8 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; 82 is a cleaner for removing dirt from the surface of the belt 1; and 7 is a tension adjustment roll for applying a constant tension to the belt 1. It is.

In this image forming method in which multiple toner images are transferred onto a recording sheet, the premise of forming a high-quality recorded image without any misalignment is that the recording sheet is accurately conveyed along a predetermined path. This is very 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 1 and each roll, the parallelism of the rolls that stretch the belt, etc. be.

Therefore, conventionally, in this type of image forming apparatus, the movement of the belt in the width direction on the roll (hereinafter referred to as belt walk)
A mechanism is provided to prevent the bell from meandering.

Specific example 7: As an i-mechanism, for example, as shown in FIG. 5, a cylindrical rigid roll a has flange-shaped kite portions 1/l-b fixed at both ends, or as shown in FIG. A guide roll C that rotates freely on both ends of the outer peripheral surface of roll a.
It has been proposed that the In these mechanisms, the end surface of the belt d (hereinafter referred to as belt edge) is brought into contact with the guide surface of the guide portion 4Δb or the outer circumferential surface C1 of the guide roll C. Since the belts 1 to d are conveyed while
is held in place relative to the belt, preventing belt walking.

In addition, in FIG. 5 and FIG. 6, the code|symbol e is a frame which supports the rotating shaft a1 of the roll a.

Separately from this, a so-called active steering method has also been proposed in which the belt is actively moved in the width direction, the belt walk that has occurred is corrected, and the amount of t-slip is suppressed within a predetermined tolerance.

Specifically, the negative roll is a steering roll whose alignment can be changed with respect to the other rolls, and by giving this roll 4 an angle according to the amount of correction of the belt 1, the belt 1 is guided to a predetermined conveyance path. This is how it works.

[Problems to be Solved by the Invention] However, in the former method, the belt is held in a predetermined conveyance path against the force that tends to cause belt wow-off (hereinafter referred to as shearing force), so the belt edge A reaction force will act against the above biasing force. .

Therefore, the belt is subjected to a compressive force in the width direction, which causes wrinkles on the belt surface, and the belt edges that come into contact with the guide members are susceptible to damage such as buckling and breakage. do.

In addition, in the latter active steering method, since the roll alignment is changed mechanically, unreasonable tension may be applied to the belt, and there is a problem that it is not possible to smoothly correct belt tow. do.

The present invention has been made in view of these problems, and its object is to provide an endless belt conveying device that can prevent belt walking without damaging belt edges.

[Means for Solving the Problems] In order to achieve the above object, the endless belt conveying device of the present invention is an endless belt conveying device that stretches and conveys an endless belt using a plurality of rolls. One roll of the roll group is arranged in stages on a holding member having a shape, and a support arm is connected to the holding member so as to be slidable and rotatable along the roll axis direction,
The holding member and the support arm constitute a balance-shaped roll suspension means, and a drive means is provided for sliding the support arm by a predetermined amount in the axial direction based on a belt width direction displacement signal outputted by the detection means. It is characterized by this.

In such a technical means, the roll suspension means may be configured like a balance with the connection position to the support arm (A) as a fulcrum and perform the following operations. You can change the design of the specific configuration as appropriate.In other words, when the support arm slides and moves from its connecting position, the belt stretched around the roll is designed to balance the moment around the connecting position as the center of rotation. This is an operation in which the holding member is tilted at a predetermined angle depending on the tension distribution.

Further, as the supporting arm, if it is connected to the holding member so as to be slidable in the axial direction, and the angle created between the holding member and the arm can be freely changed around the connecting position, the specifics of the connection may be used. The design structure etc. may be changed as appropriate. Further, the connecting arm does not necessarily have to be a rigid body, and may be an elastic member such as a spring.

Furthermore, the configuration of the detection means may be changed as appropriate, such as one that detects displacement of the belt end surface or one that reads displacement of a position detection mark provided on the belt surface. However, in the former case, the straightness of the belt end surface has a large effect on the detected value, so from the viewpoint of controlling the belt more accurately, it is preferable to use the latter detection means.

Further, as the driving means, as long as the support arm can be moved along the axial direction in accordance with the belt displacement signal outputted from the detection means, the structure thereof may be changed in design as appropriate, for example, A ball screw that converts rotational motion into linear motion can be used, and a stepping motor or a nervo motor can be used as the driving source.

The endless belt may be made of any material and manufactured by any company.

Examples include a semiconductive electrostatic attraction belt that conveys a recording sheet such as paper, an ink recording medium in a transfer recording device, and a belt-shaped photoreceptor in an electrophotographic recording device.

[Work] The above technical means works as follows.

By sliding the support arm a predetermined amount along the roll axis direction, the rotational moment i~ acting on the holding member constituting the scale-shaped roll suspension means changes, so that the holding member rotates around the connection position of the support arm. Causes rotation. When the holding member rotates, the tension distribution in the width direction of the belt stretched across the rolls changes and the angle at which the rolls are arranged changes, causing belt torsion. Then, when a predetermined amount of Peltor torsion occurs, the rotational moment acting on the holding member regains its equilibrium, so the rotation of the holding member stops.
Belt walking also stops. Therefore, by sliding the support arm by a predetermined distance by the drive means based on the displacement of the belt in the width direction detected by the detection means, the belt 1 to 4 is rotated by an arbitrary distance in an arbitrary direction.
The movement of the belt in the width direction can be controlled.

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

1 and 2 show a schematic configuration of an endless belt conveying device of the present invention, which can be applied to the recording sheet conveying mechanism of the color image forming apparatus shown in FIG. 8.

Specifically, a drive roll 2 is connected to a motor H and rotates in the arrow direction, a steering roll 4 is installed astride a scale-shaped roll suspension means 3 and corrects displacement of the belt 1 in the width direction; a detecting means 5 for detecting displacement of the belt 1 in the width direction; a driving means 6 for controlling the movement of the steering roll 4 by driving the roll suspension means 3 based on a control signal outputted by the detecting means 5; 1-1
The endless belt is composed of driven rolls 21 and 22 that rotate as the sheet is transported, and a tension horn adjustment [1-lua] that applies a constant tension to the bell j~1, and that carries and transports the recording sheet by the roll group. 1 is strung up.

The belt 1 is an annular body that holds and conveys the recording sheet by electrostatic attraction, and has a two-layer structure consisting of an insulating inner layer 11 and a semiconductive outer layer 12, as shown in FIG. , 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 each electrode 13 can be energized by connecting a plurality of brush power feeders (not shown) to the exposed portion 14. 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.

Next, there is a roll suspension means 3 on which the steering roll 4 is straddled.
and a support arm 32 which is pivotally attached to and supports this holding member 31, and is formed into a substantially scale-like shape with the connection point 33 between the holding portion vj31 and the support arm 32 as the center of rotation. Further, the support arm 32 is connected to the holding member 31 so as to be freely slidable along the axial direction of the roll 4, so that the length of the arm of the holding member 31 on the left and right sides of the connection point 33 can be changed as appropriate. It has become.

On the other hand, the driving means 6 includes a stepping motor 61 that excites a rotational movement of a predetermined angle based on the belt displacement signal outputted from the detection means 5, and a stepping motor 61 that converts the rotational movement of this motor 61 into a linear movement to convert the supporting arm into a linear movement. 32 and a ball screw 62 that drives the roll 4 along the axial direction.

Further, the detection means 5 is disposed on one side of the belt 1 to measure the distance to the belt edge, and calculates and outputs the displacement amount of the belt 1 in the width direction based on the measured data. In order to eliminate measurement errors due to poor straightness of the belt edge, measurements are taken only at - or multiple specific points on the belt edge, and the amount of displacement of the belt 1 is determined by comparing the previous measurement data and the current measurement data at the relevant points. I am trying to calculate.

In the apparatus of this embodiment configured as described above, the support arm 32 of the roll suspension means 3 is moved in the axial direction by the drive means 6 based on the width direction displacement of the belt 1 detected by the detection means 5. By sliding the steering roll 4 by a predetermined amount, the alignment of the steering roll 4 is changed and belt walking occurs, and the displacement of the belt 1 in the width direction can be arbitrarily controlled.

Hereinafter, the operation for correcting belt displacement will be explained using the attached FIGS. 3(A) to 3(C).

First, FIG. 3(A) shows a state in which the support arm 32 is connected to the axial center of the holding portion +A31.

In this state, a -like tension T is acting on the belt 1 stretched across the roll 4 in the width direction, and the support arm 32
Since the lengths of the holding member 31 on the left and right sides are both p, the rotation moments acting on the holding member 31 with the connection point 33 of the support arm 32 as the center of rotation are in a balanced state.

Here, as shown in FIG. 3(B), if the support arm 32 is slid and the lengths of the holding members 31 on the left and right sides of the connecting point 33 are set to p1 and f12, respectively, the balance of the rotation moment will be lost, so the holding member 31 and the steering roll 4 are rotated in the direction of the arrow Δ.

As the holding member 31 rotates about the connecting point 33 in this way, the alignment of the steering roll 4 changes, so that the belt 1 causes a pert tow in the direction of the arrow X, and the tension distribution of the belt 1 changes. Larger A2 on A1 side
It gets smaller on the side. Then, as the tension distribution of the belt 1 changes, the rotation moment acting on the holding member 31 is balanced again, and the rotation of the holding member 31 and the belt walking are stopped.

Therefore, according to this embodiment, by sliding the support arm 32 by a predetermined amount using the drive means 6, the belt 1 can be displaced by an arbitrary amount in the width direction, so that the belts 1 to 1 can be moved without damaging the belt edges. It is possible to maintain a predetermined transport path.

Further, since the alignment changes depending on the balance of the rotating wheels acting on the steering roll 4, no unreasonable tension is applied to the belt, and the belt can be smoothly corrected to a predetermined conveyance path.

In addition, in the endless belt conveying device of this embodiment that has been explained above, only the minimum necessary configuration has been explained to simplify the explanation, but if necessary, auxiliary equipment such as a cleaner may be provided around the belt. Of course, there is no problem.

[Effects of the Invention] As explained above, according to the endless belt conveying device of the present invention, the support arm constituting the roll suspension means is slid by a predetermined distance based on the displacement of the belt in the width direction that has occurred. Since the movement of the belt in the width direction is controlled, it is possible to smoothly maintain the belt on a predetermined conveyance path without damaging the belt edges.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a first embodiment of the endless belt conveying device of the present invention, FIG. 2 is a front view showing a schematic configuration of the first embodiment, and FIGS. An explanatory diagram showing the operation of the device according to the embodiment, FIG. 4 is a perspective view showing the endless belt according to the first embodiment, and FIGS. 5 and 6 are conventional means for preventing belt sagging. FIG. 7 is a schematic diagram showing an example of a color image forming apparatus to which the present invention is applicable. [Description of symbols] 1: Endless belt 3: Roll suspension means 4 Steering roll 5: Detection means 6: Drive means 31: Holding member 32: Support arm

Claims (1)

[Scope of Claims] An endless belt conveying device that stretches and conveys an endless belt using a plurality of rolls, wherein one roll of the group of rolls is mounted on a substantially U-shaped holding member; A support arm is connected to the holding member so as to be slidable and rotatable along the roll axis direction, and the holding member and the support arm constitute a balance-shaped roll suspension means. An endless belt conveyance device, comprising a drive means for sliding the support arm by a predetermined amount in the axial direction based on a width direction displacement signal.