JPH04159911A - Belt conveyor - Google Patents

Abstract

PURPOSE:To prevent the damage of the end edge of a belt by bringing an edge guide into contact with one side end edge of the belt via the exiting force of a spring, detecting the exiting force of the spring, and adjusting the alignment of a steering roll to keep the exciting force constant. CONSTITUTION:An edge guide 60 is brought into contact with one side edge of a conveyance belt 37 via the exiting force of a coil spring 62, an optical displacement sensor 63 is fitted to a frame 50, and the relative distance between the edge guide 60 and the frame 50 is measured. When the belt 37 is moved in the direction A from the reference position, the edge guide 60 is also moved in the same direction, and the displacement sensor 63 detects the displacement and inputs it to a driving circuit 65. The driving circuit 65 drives a motor 53 to adjust the alignment of a steering roll 32 based on the detection signal so that the conveyance belt 37 is moved in the opposite direction to the direction A and returned to the reference position.

Description

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

[Conventional technology]

Conventionally, this type of belt conveying device has been used, for example, in so-called tandem color printers (for example, in Japanese Patent Application Laid-Open No. 1983-1999).
74036, JP-A-62-165676)
.

This type of color printer has, for example, four sets of image forming units that form toner images of cyan, magenta, yellow, and black threads, and a recording sheet is sequentially conveyed toward the image transfer site of each image forming unit. It consists of a sheet conveyance system. As the sheet conveyance system, a plurality of roll groups including at least a drive roll and a steering roll for alignment adjustment are arranged in parallel, an endless belt is stretched around these roll groups, and a recording sheet is placed on this endless belt. The recording sheet is conveyed by holding the recording sheet.

By the way, in this type of tandem color printer, toner images of multiple systems are transferred multiple times to a single recording sheet being conveyed, so it is possible to produce high-quality color images without color shift. To achieve this, it is necessary for the recording sheet to be conveyed accurately along a predetermined path, and it is important to design a belt that conveys the recording sheet to effectively prevent it from meandering in the width direction. This has become a major issue.

However, considering imperfections in the forming of the belt and each roll, the parallelism of the rolls that stretch the belt, etc., it is virtually impossible to completely prevent the belt from meandering in the width direction. In this case, a means is provided to prevent the belt from meandering in the width direction.

As a meandering prevention means for this type of belt, a so-called L L is used, in which a large number of elastic support fins that can be elastically displaced along the axial direction of the roll are protruded from the outer periphery of at least one roll.
In addition to forming an F (Low Lateral force) roll, a flange-shaped edge guide is fixedly formed at one end of this roll, and the acting force (Edge Force) from the edge guide generated on the belt is reduced by the elastic support fins and edge guide. It has been proposed to forcibly restrict movement of the belt in the width direction (see Japanese Patent Laid-Open No. 58-17781).

[Problem to be solved by the invention]

However, in the above-mentioned types, it is virtually impossible to form the edge shape of the belt into a perfectly straight line, so when the edge of the belt comes into contact with the fixed edge guide during roll rotation, On the contrary, the edge guide presses the belt and changes its position in the width direction, which may cause a technical problem in that the positional deviation of the toner images of each color thread in multiple transfer becomes more noticeable. .

In addition, in the above-mentioned type, when the edge of the belt comes into contact with the fixed edge guide, the edge force changes depending on the shape of the edge of the belt, but the range of variation in the edge force is large. If this happens, the edge of the belt will be damaged, so it is necessary to suppress the fluctuation range of the edge force as much as possible, or in other words, to keep the edge force constant.

At this time, the edge force mentioned above is determined according to the accuracy of the parts and assembly, so in order to keep the edge force constant, it is necessary to improve the linearity of the edge shape of the belt and the smoothness of the contact surface of the edge guide. In order to improve the molding accuracy of parts, it is necessary to accurately adjust the edge force after assembly (for example, measure the edge force and manually adjust the steering roll for alignment adjustment). A technical problem arises in that part molding work and edge force adjustment work become troublesome.

This invention was made to solve the above technical problem, and the edge force acting on the edge of the belt can be kept constant very easily, and damage to the edge of the belt can be effectively avoided. The present invention provides a belt conveying device as described above.

[Means to solve the problem]

That is, the inventor of the present application has devised the following three inventions to solve the above technical problems.

In the first invention, as shown in FIG. 1(a), a plurality of roll groups 1 including at least a drive roll 1a and a steering roll 1b for alignment adjustment are arranged in parallel,
A belt conveying device is assumed in which an endless belt 2 is stretched around these roll groups 1, and the endless belt 2 is brought into contact with one edge of the belt 2 and is elastically biased toward the belt 2 side by a spring member 4. an edge guide 3; a biasing force change detection means 5 for detecting a biasing force change of the spring member 4;
The present invention is characterized by comprising alignment control means 6 for adjusting the alignment of the steering roll 1b so that the urging force of the spring member 4 is constant based on the urging force change information from the urging force change detection means 5. It is something.

Further, the second invention is based on a belt conveying device having a roll group 1 and an endless belt 2 similar to the first invention, as shown in FIG. 1(b), and one side end of the belt 2 is an edge guide 3 that abuts the edge and is elastically biased toward the belt 2 side by a spring member 4; a displacement detecting means 7 that detects the displacement of one edge position of the belt 2 from a reference position; It is characterized by comprising an alignment control means 8 which adjusts the alignment of the steering roll 1b so that the position of one edge of the belt 2 moves toward the reference position based on the displacement information from the displacement detection means 7. be.

Furthermore, the third invention is based on a belt conveying device having a roll group 1 and an endless belt 2 similar to the first invention, as shown in FIG. An edge guide 9 that is fixedly disposed on the side and comes into contact with one edge of the belt 2, an acting force detecting means lO for detecting the acting force of the belt 2 on the edge guide 9, and an acting force detecting means 10 from the acting force detecting means 10. The present invention is characterized by comprising an alignment control means 11 that adjusts the alignment of the steering roll 1b so that the acting force becomes constant based on acting force information.

In such technical means, the endless belt 2 may include a sheet conveyance belt that conveys a recording sheet (such as a sheet conveyance belt with an electrostatic adsorption belt gripper), a latent image bearing belt that carries an electrostatic latent image, Examples include an intermediate transfer body conveyance belt.

Also, movable edge guide 3. The fixed edge guide 9 may be provided at least on one side edge of the endless belt 2, but may be provided on both side edges of the endless belt 2. In this case, from the viewpoint of effectively preventing buckling deformation of the belt 2, the edge guides 3 and 9 should be arranged at arcuate locations on the belt 2 (locations with high surface rigidity). Specifically, the edge of the roll l or a location near the edge is preferable. Also, regarding the location where the belt 2 is regulated by the edge guide 3, the belt 2
Although it is sufficient to provide at least one location in the conveyance direction of the belt 2, from the viewpoint of further strengthening the meandering prevention function in the width direction of the belt 10, it is preferable to provide it in multiple locations in the conveyance direction of the belt 2.

The spring member 4 may be any material that can elastically support the edge guide 3 and has at least enough elasticity to prevent the edge force acting from the edge guide 3 to the belt 2 from becoming extremely large. The structure may be appropriately selected from coil springs, plate springs, elastic pads, etc.

Furthermore, the biasing force change detecting means 5 may detect a change in the biasing force itself, as well as a parameter that leads to a change in the biasing force (for example, displacement of the spring member 4, etc.).
There is no problem even if it is designed to detect.

Furthermore, the displacement detecting means 7 may be appropriately selected from an optical type, mechanical type, electric type, etc. as long as it can detect the position of one edge of the belt 2.

Further, as the acting force detecting means 10, any suitable device including a strain gauge can be selected as long as it detects the acting force on the fixed edge guide 9.

Further, as the alignment control means 6, 8.11, the respective urging force change detection means 5. Steering roll 1 based on information from displacement detection means 71 acting force detection means 10
As long as the alignment control of b can be realized, the design may be changed as appropriate. In this case, from the viewpoint of stabilizing the alignment control of the steering roll 1b, it is preferable to cut the high frequency components of the belt 2 using a low-pass filter.

[Effect]

In the above-mentioned technical means, according to the first invention, when the endless belt 2 starts to be displaced from the reference position in the width direction, the spring member 4 starts to be displaced via the edge guide 3.

Then, the biasing force change detection means 5 detects a change in the biasing force of the spring member 4, and the alignment control means 6 controls the biasing force of the spring member 4 to be constant based on the information from the biasing force change detection means 5. steering roll 1b
The alignment of the belt 2 is adjusted and the displacement of the belt 2 in the width direction is corrected.

Further, according to the second invention, when the endless belt 2 starts to displace from the reference position in the width direction, the displacement detection means 7 detects the amount of displacement of the belt 2, and the alignment control means 8 detects the amount of displacement of the belt 2. Based on the information from the steering roll 1b, the steering roll 1b
The alignment of the belt 2 is adjusted and the displacement of the belt 2 in the width direction is corrected.

Furthermore, according to the third invention, when the endless belt 2 starts to displace from the reference position in the width direction, the displacement movement of the belt 2 is blocked by the fixed edge guide 9, but at this time, the acting force is detected. The means 10 detects changes in the force acting on the edge guide 9, and the alignment control means 11 aligns the steering roll 1b so that the force acting on the edge guide 9 is constant based on information from the force detecting means IO. adjustment to correct the displacement of the belt 2 in the width direction.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

◎Embodiment 1 Fig. 2 shows a so-called tandem type color printer to which the present invention is applied.

In the figure, reference numerals 10a to 10d (the whole is indicated by 10) are image forming units that respectively form cyan, magenta, yellow, and black toner images by an electrophotographic process. Unit 10 is
A photosensitive drum 21 (specifically, 21a to 21d) and a charging corotron 22 that charges the surface of the photosensitive drum 21 in advance.
(specifically 22a to 22d), a semiconductor laser 23 (specifically 23a to 23d) that writes an electrostatic latent image on the charged photosensitive drum 21, cyan, magenta, yellow,
The developing device 24 (
24a to 24d) and a cleaner 25 (specifically 24a to 24d) for removing residual toner on the photosensitive drum 21.
5a to 25d).

Further, reference numeral 30 denotes a sheet conveyance system for conveying the recording sheet 39, which includes a drive roll 31 that is rotationally driven by a drive motor (not shown), and an alignment adjustment mechanism (not shown) that is arranged parallel to the drive roll 31. A steering roll 32 whose alignment is adjusted, a drive roll 31 . An appropriate number of driven rolls 33 to 36 arranged parallel to the steering roll 32 and a group 3 of these rolls.
1 to 36, and an endless conveyor belt 37 that electrostatically holds and conveys the recording sheet 39. In this embodiment, the steering roll 32 and the driven rolls 33 to 36 are so-called LLF (Low La
(teral force) roll is adopted (see Japanese Patent Application Laid-Open No. 177811/1983).

A sheet feeding cassette 3 is attached to the conveyor belt 37.
A tacking roll 40 for tacking the recording sheets 39 from 8 to 8 is provided, and an electrostatic transfer roll 26 (specifically 26a to 26d) is provided on the back side of the conveyor belt 37 corresponding to all the image forming units 10. ) is arranged,
The toner images formed on the photosensitive drums 21 of each image forming unit 10 are electrostatically transferred onto a recording sheet 39 on a conveyor belt 37, and the recording sheet 39 on the conveyor belt 37 is transferred to a steering roll 32. The recording sheet 39 is separated from the conveyor belt 37 at a corner corresponding to the recording sheet 39 , and the separated recording sheet 39 is discharged to the discharge tray 41 via the fixing device 27 .

Furthermore, in this embodiment, the conveyor belt 3
A tension adjustment roll 42 is placed under pressure at the conveyor belt 7 to apply appropriate tension, and a cleaner 43 is attached to the conveyor belt 37 to clean paper dust etc. adhering to the conveyor belt 37.
is provided.

Further, a meandering prevention device for the conveyor belt 37 in this embodiment is shown in FIG.

In the figure, one end side support part of the steering roll 32 is rotatably supported by a frame 50 via a radial bearing 51, and the other end side support part of the steering roll 32 is rotatably supported by a radial bearing 52. This radial bearing 52 is placed on an eccentric cam 54 that is eccentrically rotated by a motor 53, and is moved up and down as appropriate according to the eccentric position of the eccentric cam 54, thereby adjusting the alignment of the steering roll 32. It is about to be done.

Further, an edge guide 60 is movably supported on one end side support portion of the steering roll 32 via a thrust bearing 61, and between this edge guide 60 and the frame 50 is a coil spring 62 (for example, Spring constant: 0.05-0.5 kg f/
mm) is interposed. An edge guide 50 is provided in the portion of the frame 50 that faces the edge guide 50.
(equivalent to the amount of displacement of the coil spring 62)
An optical displacement sensor 63 is attached to detect the .

The displacement information from the displacement sensor 63 is transmitted to the conveyor belt 37.
The signal is inputted to the drive circuit 65 via a low-pass filter 64 in which frequency components higher than one cycle of are cut. A drive control signal corresponding to the displacement information is sent from the drive circuit 64, and this drive control signal is input to the motor 53 to control the eccentric cam 54 so that the amount of displacement of the coil spring 62 is constant. The alignment of the steering roll 32 is adjusted through the steering roll 32.

Next, the operation of the meandering prevention device according to this embodiment will be explained.

Now, if the conveyor belt 37 starts to displace from the reference position shown by the solid line in FIG. 3 in the direction of arrow A, the edge guide 60
is displaced accordingly.

At this time, the displacement sensor 63 detects the displacement of the edge guide 60, and the displacement data of the displacement sensor 63 is inputted to the drive circuit 65 via the low-pass filter 64.

Then, a drive control signal is sent from the drive circuit 65, the motor 53 is rotated as appropriate, and the alignment of the steering roll 32 is adjusted via the eccentric cam 54.

At this stage, the displacement amount of the displacement sensor 63 is controlled to be constant (so that the biasing force of the coil spring 62 is constant), and the movement of the conveyor belt 37 in the width direction is immediately returned to the reference position. It will be done.

In this embodiment, the displacement of the coil spring 62 is directly detected, but for example, as shown in FIG. A similar device can be configured by using this displacement data.

◎Example 2 As shown in FIG. 5, the conveyor belt meandering prevention device according to this example differs from Example 1 in that a plate-shaped edge guide 80 that can be elastically deformed is provided at one end of the steering roll 32. This edge guide 80 is installed using one piece 8.
1 to the frame 50, for example, a strain gauge 82 is attached to a part of the edge guide 50, and the gauge output from the strain gauge 82 is passed through a low-pass filter 83.
The motor 53 is appropriately driven based on the drive control signal from the drive circuit 84, the alignment of the steering roll 32 is appropriately adjusted by the eccentric cam 54, and the gauge output of the strain gate 82 is input to the drive circuit 84 via the drive circuit 84. is kept at a constant level.

Therefore, according to this embodiment, when the conveyor belt 37 begins to displace from the reference position indicated by the solid line in FIG. 3 in the direction indicated by the arrow, the edge guide 80 warps and deforms.

At this time, the gauge output of the strain gauge 82 changes according to the warping deformation of the edge guide 80, and the low-pass filter 8
3 to the drive circuit 84.

Then, a drive control signal is sent from the drive circuit 84, the motor 53 is rotated as appropriate, and the alignment of the steering roll 32 is adjusted via the eccentric cam 54.

At this stage, the gauge output of the strain gauge 82 (corresponding to the force acting on the edge guide 80) is controlled to be constant, and the movement of the conveyor belt 37 in the width direction is immediately returned to the reference position.

◎Modifications In each of the above embodiments, the alignment of only one steering roll 32 is adjusted, but the alignment is not limited to this. For example, as shown in FIG. In addition, for example, the driven roll 33 (
Furthermore, by configuring the other driven rolls (other driven rolls) as steering rolls and adjusting the alignment of the plurality of steering rolls 32 and 33, the meandering of the conveyor belt 37 in the width direction can be corrected at multiple points. 37 can be returned to the reference position more quickly.

Further, the configuration of the edge guide 60 (80) is not limited to that shown in each of the above embodiments. For example, as shown in FIG. By forming this, when the conveyor belt 37 is displaced outward in the width direction, a force is generated from the edge guide 60 (80) to the conveyor belt 37 in the direction of returning the displacement, and the meandering of the conveyor belt 37 is effectively prevented. Can be regulated. Furthermore, if the edge guide 50 (80) is rotatably supported by a radial bearing 91,
One edge of the conveyor belt 37 and the edge guide 5
0 (80) can be effectively avoided.

〔Effect of the invention〕

As described above, according to the invention described in claims 1 to 3, in a type in which movement of the belt in the width direction is corrected by an edge guide, information corresponding to the edge force by the edge guide is detected, and based on this detected information, Since the steering roll alignment is adjusted to keep the edge force caused by the edge guide constant, it is possible to effectively avoid damage to the belt edge caused by the edge force that occurs in the fixed edge guide system.

Further, according to the present invention, when assembling the device or parts (belt,
Even if the load acting on the edge guide (equivalent to edge force) changes when replacing rolls, the edge force is automatically kept constant, which improves the forming accuracy of parts by keeping the edge force constant. , there is no need to perform edge force adjustment work, and device assembly work and parts replacement work can be simplified accordingly.

Furthermore, even in the case of a type in which the edge guide is supported by a spring member, as in the invention described in claims 1 and 2, the edge force can be automatically kept constant, so setting the initial load of the spring member is omitted. be able to.

[Brief explanation of the drawing]

1(a), (b), and (c) are explanatory diagrams showing a schematic configuration of a belt conveying device according to the present invention; FIG. 2 is an explanatory diagram showing a first embodiment of a color printer to which the present invention is applied; FIG. 3 is an explanatory diagram showing the conveyor belt meandering prevention device used in the first embodiment, FIG. 4 is an explanatory diagram showing a modification thereof, and FIG. 5 is an explanatory diagram showing the conveyor belt meandering prevention device according to the second embodiment. 6 are explanatory diagrams showing a modification of the conveyor belt meandering prevention device, and FIG. 7 is an explanatory diagram showing a modification of the edge guide. [Explanation of symbols] 1...Roll 1a...Drive roll 1b...Steering roll 2...Belt 3...Edge guide 4...Spring member 5...Biasing force change detection means 6...・Alignment control means 7...Displacement detection means 8...Alignment control means 9...Edge guide lO...Action force detection means 11...Alignment control means Patent applicant Fuji Xerox Co., Ltd. Agent
Patent Attorney Tomohiro Nakamura (2 others) Figure 1 (a) Figure 1 (b) Figure 1 (c) Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1) A plurality of roll groups (1) including at least a drive roll (1a) and a steering roll (1b) for alignment adjustment are arranged in parallel, and an endless belt ( In the belt conveying device in which the belt (2) is stretched over the edge guide ( 3), a biasing force change detecting means (5) for detecting a change in the biasing force of the spring member (4), and a biasing force change detecting means (5) for detecting a change in the biasing force of the spring member (4) based on the biasing force change information from the biasing force change detecting means (5). A belt conveying device comprising: alignment control means (6) for adjusting the alignment of the steering roll (1b) so that the urging force of the steering roll (1b) is constant. 2) A plurality of roll groups (1) including at least a drive roll (1a) and a steering roll for alignment adjustment (1b) are arranged in parallel, and an endless belt (2) is stretched around these roll groups (1). An edge guide (3) that abuts one edge of the belt (2) and is elastically biased toward the belt (2) by a spring member (4); (2) displacement detecting means (7) for detecting the displacement of the one side edge position from the reference position; and the one side edge position of the belt (2) based on the displacement information from the displacement detecting means (7). A belt conveying device comprising: alignment control means (8) for adjusting the alignment of the steering roll (1b) so that the steering roll (1b) is directed toward a reference position. 3) A plurality of roll groups (1) including at least a drive roll (1a) and a steering roll for alignment adjustment (1b) are arranged in parallel, and an endless belt (2) is stretched around these roll groups (1). An edge guide (9) fixedly arranged on one side in the width direction of the belt (2) and abutting on one side edge of the belt (2); An acting force detection means (10) detects the acting force on the edge guide (9), and the steering roll ( 1b) alignment control means (11) for adjusting the alignment of the belt conveying device.