JPH06127729A - Cleaning device for speed detecting roll for endless belt of image forming device - Google Patents

Abstract

PURPOSE:To prevent the variation of the outside diameter of a speed detecting roll by removing the foreign material adhering on the speed detecting roll. CONSTITUTION:When the foreign material 31 such as toner adheres on an encoding roll 28, during the use of an image forming device, the foreign material 31 is shifted to a cleaning brush 33, accompanied with the revolution of the encoding roll 28. The foreign material 31 is scraped off from the encoding roll 28 by the cleaning brush 33, and collected in a foreign material collecting part 34a. Since the foreign material 31 adhering on the encoding roll 28 is surely scraped by the cleaning brush 33, the outside diameter of the encoding roll 28 is prevented from being varied. Accordingly, the encoding roll 28 can correctly detect the revolution speed of a copying belt 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an image forming apparatus such as an electrophotographic copying machine or a printer, and an endless transfer belt for transferring a transfer material or an endless toner image formed by a developing device. The present invention relates to an endless belt of an image forming apparatus including an endless belt such as a photosensitive belt, and more particularly to a cleaning device for an endless belt of an image forming apparatus that cleans the surface of a speed detection roll that detects the rotation speed of the endless belt.

[0002]

2. Description of the Related Art Conventionally, an endless belt conveying device of an image forming apparatus such as an electrophotographic copying machine or a printer is used to transfer a toner image formed on a photosensitive drum onto a transfer material such as a transfer paper, a paper tray or the like. The transfer material supplied from the transfer material accommodating means is carried by an endless conveyor belt and conveyed to the transfer position of the photosensitive drum. Then, after the toner is transferred from the photosensitive drum to the transfer material, the transfer material is further transported to the fixing device by the transport belt in order to fix the toner image transferred on the transfer material.

By the way, in this endless belt conveying device, in order to accurately transfer the toner image of the photosensitive member onto the transfer material, the rotation of the photosensitive drum and the rotation of the conveying belt must be accurately synchronized. Therefore, it is necessary to accurately detect the rotation speed of the conveyor belt. As a method of accurately detecting the rotation speed of the conveyor belt, conventionally, a speed detection roll having a predetermined radius of rotation is brought into contact with the conveyor belt, and the speed detection roll is rotated in synchronization with the rotation of the conveyor belt. The rotation speed of the conveyor belt is detected by detecting the rotation speed of the roll.

[0004]

However, in the detection of the rotational speed of the endless belt by such a conventional speed detecting roll, foreign matter such as toner and dust adheres to the surface of the speed detecting roll over time. become. When foreign matter adheres to the surface of the speed detection roll in this way, the outer diameter of the speed detection roll changes. For this reason, the rotation speed detected by the speed detection roll is different from the actual rotation speed of the endless belt, and the speed detection roll cannot accurately detect the rotation speed of the endless belt. In particular, if foreign matter partially adheres to the surface of the speed detecting roll, the outer diameter of the speed detecting roll will change partially. Therefore, the speed detection roll cannot stably and accurately detect the rotation speed of the endless belt.

The present invention has been made in view of the above problems, and an object thereof is to prevent the outer diameter of the speed detecting roll from changing by removing foreign matters adhering to the speed detecting roll. A cleaning device for a speed detection roll in an endless belt of an image forming apparatus is provided.

[0006]

In order to solve the above-mentioned problems, the invention of claim 1 is provided with a speed detecting roll for detecting the rotation speed of the endless belt. The speed detection roll detects the rotation speed of the endless belt by rotating in association with the rotation of the endless belt. Further, a cleaning member for the speed detection roll is provided, and this cleaning member contacts the surface of the speed detection roll to clean the surface. Since the cleaning member removes foreign matters such as toner adhering to the surface of the speed detecting roll, the outer diameter of the speed detecting roll does not change. As a result, the speed detection roll can accurately detect the rotation speed of the endless belt for a long time.

According to the invention of claim 2, the cleaning member comprises a cleaning brush, and in the invention of claim 3, the cleaning brush is formed of a conductive material.

Further, in the invention of claim 4, a cleaning brush is planted on at least a part of the surface of the roll.
The roll can be selectively set in a rotatable state and a fixed state, and is rotated by a motor.
Further, the motor drive control device controls the drive of the motor so that the motor rotates at a predetermined angle at a predetermined interval. As a result, the cleaning brush implanted in the roll has no unused portion, and the entire brush is used uniformly. Therefore, the speed detection roll is cleaned more effectively by the cleaning brush.

Further, according to the invention of claim 5, the cleaning brush driving means selectively sets the cleaning brush to the contact state or the separated state with respect to the speed detection roll. As a result, the cleaning brush can be separated from the speed detection roll when the image forming apparatus is not in use, so that it is possible to prevent the cleaning brush from being in constant contact with the speed detection roll and causing deterioration such as early setback. .

Further, in the sixth aspect of the invention, the cleaning brush control means sets the cleaning brush in a separated state from the speed detection roll during the image forming operation of the image forming apparatus, and during the non-image forming operation of the image forming apparatus. The cleaning brush is set in contact with the speed detection roll. As a result, during the image forming operation of the image forming apparatus, the cleaning brush is held in a state of being separated from the speed detecting roll, so that the cleaning work of the speed detecting roll is not performed.

Therefore, during the image forming operation of the image forming apparatus, the speed detecting roll is not affected by the load of the cleaning brush, so that the speed detecting roll can rotate more accurately. Therefore, the image forming apparatus can perform image formation with high accuracy.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. As an example of an image forming apparatus to which the present invention is applied, FIG. 1 is a diagram schematically showing a developing device, a transfer device, a fixing device, and paper feeding, transporting, and discharging devices in a tandem digital color copying machine. Is.

As shown in FIG. 1, in this digital color copying machine 1, four photoconductor drums 2Y, 2M, 2 corresponding to each color of yellow Y, magenta M, cyan C, and black K are provided.
C and 2K are respectively arranged in this order from the right side in the drawing, that is, at a predetermined distance from the paper supply side. In the vicinity of the outer circumference of these photosensitive drums 2Y, 2M, 2C, 2K,
Primary chargers 3Y, 3M, 3C and 3K are arranged respectively. These primary chargers 3Y, 3M, 3C, 3K are provided on the surfaces of the corresponding photoconductor drums 2Y, 2M, 2C, 2K, for example, -500-8.
It is uniformly charged to 00V.

Further, exposure devices 4Y and 4 such as a laser beam exposure device are provided downstream of the primary chargers 3Y, 3M, 3C and 3K near the outer circumferences of the photosensitive drums 2Y, 2M, 2C and 2K in the rotational direction.
M, 4C, 4K are disposed, further developing devices 5Y, 5M, on the downstream side in the rotational direction of the exposure devices 4Y, 4M, 4C, 4K near the outer periphery of each photoconductor drum 2Y, 2M, 2C, 2K, respectively. 5C and 5K are arranged.
The exposure devices 4Y, 4M, 4C, 4K irradiate a color-separated light image or a light image corresponding thereto to form an electrostatic latent image on the photoconductor drums 2Y, 2M, 2C, 2K, and a developing device. 5Y, 5M, 5C, and 5K develop the electrostatic latent image on the photoconductor drums 2Y, 2M, 2C, and 2K formed in this way with toner to form a visible image.

A transfer device 6 is arranged under each of the photosensitive drums 2Y, 2M, 2C and 2K. The transfer device 6 is arranged in contact with each of the photoconductor drums 2Y, 2M, 2C, and 2K, and has an endless transfer belt 7 of a predetermined length that conveys a transfer material, and each photoconductor drum.
It is composed of transfer chargers 8Y, 8M, 8C and 8K, which are arranged to face each other at the lowermost transfer points of 2Y, 2M, 2C and 2K.

The transfer belt 7 is formed by integrally forming a transfer material carrying sheet made of a dielectric material and a conveying sheet made of an insulating material or a high resistance material, for example, polyethylene terephthalate (PET) or polyvinylidene fluoride resin film. It is composed of a transport sheet made of a dielectric material. Further, the transfer belt 7 is a driven roller 10 which is a driven roller arranged on the opposite side of a drive roller 9 connected to a dedicated motor (not shown) having excellent constant speed.
A fixed tension is applied between the two and to stretch them, and the drive roller 9 rotates them in the direction of arrow A, that is, in the counterclockwise direction. Further, the transfer belt 7 is also stretched over the peeling roller 12 and the idler roller 13 of the transfer material peeling means 11 provided at the transfer material peeling position.

The transfer chargers 8Y, 8M, 8C and 8K are corona chargers, and different voltages are applied in the range of, for example, +4.2 KV to +12.0 KV, and the transfer current is +50 μA to +2000 μA. To be done. By this transfer current, the toner on the photoconductor drums 2Y, 2M, 2C, K is transferred onto the transfer paper 1
7 is electrostatically adsorbed.

In the vicinity of the driving roller 9 of the transfer belt 7,
The transfer charging device 14 is arranged to face the transfer charging device 14 with the transfer charging device 14 sandwiching the transfer belt 7 between the transfer charging device 14 and the transfer charging device 14.
And a suction roller 15 which is a guide member for guiding the sheet to the transfer belt 7. Then, the transfer paper 17 such as the paper stored in the paper supply tray 16 is fed onto the transfer belt 7 by the feed roller 18 at a predetermined timing, and is attracted to the transfer belt 7 by the attraction charger 14 and the attraction roller 15. To be done.

On the other hand, the transfer material peeling means 11 includes a charge removing member 20 for weakening the electrostatic attraction force of the transfer belt 7 and the transfer paper 1.
A peeling claw 26 for peeling 7 from the transfer belt 7 is provided. Further, a fixing device 21 is provided on the downstream side of the transfer material peeling means 11, and the toner image transferred onto the transfer paper 17 is fixed by the fixing device 21. The transfer paper 17 that has been fixed is stored in the paper discharge tray 22.

Further, inside and outside the transfer belt 7, there are provided an inner charge-eliminating charger 23 and an outer charge-eliminating charger 24, which constitute a charge-eliminating means for eliminating charge from the transfer belt 7, facing each other. Further, a transfer belt cleaning means 25 for cleaning the transfer belt 7 is disposed downstream of the drive roller 9.

Hereinafter, in the full-color image forming process by the digital color copying machine of the present embodiment thus constructed, the visible image forming process and the transfer belt 7 by the developing devices 5Y, 5M, 5C and 5K are performed. The steps of adsorbing the transfer paper 17 onto the sheet and transferring the sheet will be described.

The transfer paper 17 attracted to the transfer belt 7 by the attraction charger 14 and the attraction roller 15 is transferred to the transfer belt 7.
When it reaches the transfer point of the yellow Y photoconductor drum 2Y, the Y toner image is first transferred from the photoconductor drum 2Y to the transfer paper 17. Next, transfer paper 1
7 is conveyed by the transfer belt 7, and the toner image of magenta M is transferred from the photosensitive drum 2M onto the toner image of Y on the transfer paper 17 in an overlapping manner. Thereafter, the cyan C toner image and the black K toner image are sequentially transferred so as to be superimposed on the transfer toner image on the transfer paper 17. In this way, four-color full-color multiple transfer is performed.

When the full-color multiple transfer of four colors is completed, the transfer paper 17 is discharged by the charge removing member 20 of the transfer material peeling means 11, and the transfer paper 17 is removed by the peeling roller 12 by utilizing the rigidity of the transfer paper 17. The transfer paper 17 is forcibly separated, and the transfer paper 17 is separated from the transfer belt 7 by the separation claw 26.

By the way, as shown in FIG. 1, in this endless belt device, a rotational speed detecting means 27 for detecting the rotational speed of the transfer belt 7 and the rotational speed detecting means 27 are provided.
A cleaning device 28 for cleaning each is provided.

As shown in FIG. 2, the rotation speed detecting means 27
Is an encoding roll (E / R) 28 that is in constant contact with the transfer belt 7, and the encoding roll 28
And a pinch roll 30 that pinches the transfer belt 7 by the spring force of the spring 29. Although not shown, an encoder (not shown) that generates a pulse having a frequency corresponding to the rotation speed of the encoding roll 28 is provided at the end of the rotation shaft of the encoding roll 28. Further, the pinch roll 28 is arranged at a position where the transfer paper on the transfer belt 7 cannot pass.

When the transfer belt 7 is pressed against the encoding roll 28 by the pinch roll 30, the encoding roll 28 rotates in synchronization with the rotation of the transfer belt 7 without slipping. Thereby, the encoding roll 28 can accurately detect the rotation speed of the transfer belt 7. That is, the encoding roll 28 constitutes a speed detection roll.

Further, as shown in FIG. 2, the cleaning device 32 removes foreign matter 31 such as toner adhering to the surface of the encoding roll 28. This cleaning device 32
A cleaning brush 33, which is a cleaning member that constantly contacts the surface of the encoding roll 28 to clean the surface.
And an L-shaped support member 34 that supports the cleaning brush 33.

The material of the cleaning brush 33 is optimally made of soft and highly flexible fiber such as polypropylene. The reason is that by softening the cleaning brush 33, even if the cleaning brush 33 constantly contacts the encoding roll 28, the cleaning brush 33 does not become a load that resists the rotation of the encoding roll 28.

Further, as the material of the cleaning brush 33, for example, conductive fibers such as Bertron, SA-7 or the like or a blended fiber of these conductive fibers and polypropylene is used to optimize the conductivity of the cleaning brush 33. Is desirable. By doing so, frictional electrification between the encoding roll and the cleaning brush can be suppressed, so that the amount of floating toner or foreign matter attached to the encoding roll can be reduced.

On the other hand, on the horizontal portion of the L-shaped support member 34, the foreign matter 31 scraped off by the cleaning brush 33 is provided.
A foreign material storage portion 34a is formed for storing the foreign matter.

In this embodiment thus constructed, when the transfer belt 7 rotates to the left in FIG. 2, the encoding roll 28 encodes counterclockwise in FIG. 2 in association with the rotation of the transfer belt 7. The roll 28 rotates without slipping. Then, due to the rotation of the encoding roll 28, the encoder generates a pulse corresponding to the rotation speed, and thus the rotation speed of the transfer belt 7 is detected by detecting this pulse.

When a foreign material 31 such as toner adheres to the encoding roll 28 by using the digital color copying machine, the foreign material 31 moves toward the cleaning brush 33 as the encoding roll 28 rotates. Then, the foreign matter 31 is scraped off from the encoding roll 28 by the cleaning brush 33 and accumulated in the foreign matter reservoir 34a.

In this way, the foreign matter 31 adhering to the encoding roll 28 will be
Since the cleaning brush 33, which is always in contact with the brush 8, is scraped off reliably, the outer diameter of the encoding roll 28 does not change. Therefore, the encoding roll 28 can accurately detect the rotation speed of the transfer belt 7.

FIG. 3 is a view showing another embodiment of the cleaning device 28 of the present invention. In the above-described embodiment, the cleaning brush 33 is provided in a state of being fixed to the support member 34. However, in the present embodiment, the cleaning brush 33 is rotatable with respect to the support member 34 as shown in FIG. It is planted on the surface of the roll 33a that can be selectively set in a fixed state. Also in this embodiment, the cleaning brush 33 is always in contact with the encoding roll 28 as in the above-described embodiments.

The rotary shaft of the roll 34 is connected to a motor 35, and the motor 35 is connected to a controller 36 which is a motor drive controller. The control device 36 controls the motor 35 so that the motor 35 rotates at a predetermined interval at a predetermined angle. By controlling the motor 35 in this way, the cleaning brush 33 can be used uniformly over the entire circumference of the roll 33a. As a result, the foreign matter 31 attached to the encoding roll 28 can be removed more effectively.

FIG. 4 is a diagram showing still another embodiment of the present invention. This embodiment is an embodiment in which the pinch roll 30 is not provided in the embodiment shown in FIG. In the case where the pinch roll 30 is not provided, the encoding belt 28 and the encoding roller 28 rotate without slipping in conjunction with the rotation of the transfer belt 7.
The frictional force between and cannot be obtained. Therefore, in this embodiment, as shown in FIG.
Is provided at the bent portion of the transfer belt 7.

When the encoding roll 28 is provided at the bent portion of the transfer belt 7 as described above, the encoding roll 28 is pressed against the transfer belt 7 by an actuator (not shown) so that tension is applied to the transfer belt 7. To As a result, a predetermined frictional force can be obtained between the transfer belt 7 and the encoding roll 28, and the encoding roll 28 rotates without slipping in association with the rotation of the transfer belt 7.

Moreover, since the encoding roll 28 is arranged at the bent portion of the transfer belt 7, the contact area between the transfer belt 7 and the encoding roll 28 becomes extremely large. This also provides a large frictional force between the transfer belt 7 and the encoding roll 28,
The encoding roll 28 is interlocked with the transfer belt 7 to rotate without further slipping.

FIG. 5 is a diagram showing still another embodiment of the present invention. In each of the above-described embodiments, the cleaning brush 33 is always in contact with the encoding roll 28. However, in this embodiment, the cleaning brush 33 is used when necessary.
And the cleaning brush 33 is separated from the encoding roll 28 when unnecessary.

That is, as shown in FIG. 5, the roll 33b in which the cleaning brush 33 is planted is attached to the drive shaft 37a of the solenoid 37 which is the cleaning brush drive means so that it can be selectively set in a rotatable state and a fixed state. Has been. When the solenoid 37 is not excited, the drive shaft 37a is retracted, and when the solenoid 37 is excited, the drive shaft 37a is protruded. Therefore, when the solenoid 37 is de-energized, the cleaning brush 33 is set to the retracted position shown by the chain double-dashed line and separated from the encoding roll 28. When the solenoid 37 is excited, the cleaning brush 33 is moved to the use position shown by the solid line. It is set and brought into contact with the encoding roll 28.

The solenoid 37 is connected to a control device 36 which is a cleaning brush control means, and the drive of the solenoid 37 is controlled by the control device 36. In that case, when the power source of the color copying machine is OFF, the control device 36 controls so that the solenoid 37 is not excited so that the cleaning brush 33 is separated from the encoding roll 28 when the power source of the color copying machine is not turned on. By doing so, the cleaning brush 33 is prevented from being deteriorated such as being settled at an early stage.

Further, a transfer operation detecting means 38 is connected to the control device 36. The transfer operation detecting means 38 is
When the color copying machine is performing the transfer operation, the transfer operation is detected and the detection signal is output to the control device 36. Then, the control device 36 is configured to release the excitation of the solenoid 37 by this detection signal from the transfer operation detection means 38. Thus, during the transfer operation of the color copying machine, the cleaning brush 33 is kept in a state of being separated from the encoding roll 28 so that the cleaning work of the encoding roll 28 is not performed.
As a result, during the transfer operation of the color copying machine, the encoding roll 28 is not affected by the load of the cleaning brush 33, and thus rotates more accurately. Therefore, the color copying machine can perform transfer with high accuracy.

Further, in this embodiment, when the cleaning brush 33 is in contact with the encoding roll 28, the rotation of the encoding roll 28 is not detected, and when the cleaning brush 33 is not in contact with the encoding roll 28. It is also possible to detect the rotation of the encoding roll 28. By doing so, the cleaning brush 33 does not become a load that resists the rotation of the encoding roll 28 at the time of detecting the rotation, so that the rotation speed of the transfer belt 7 can be detected more accurately and the cleaning brush can be detected. It becomes possible to form 33 from a relatively hard material as well as a soft material.

Furthermore, in this embodiment, in addition to the cleaning brush 33 embedded in the roll 33a, for example, the cleaning brush 33 of the embodiment shown in FIG. 2 can be used.

In each of the above-described embodiments, the case where the present invention is applied to the transfer belt of the tandem type digital color copying machine is explained, but the present invention is not limited to this and, for example, It can also be applied to other endless belts such as a photosensitive belt, an intermediate transfer belt, a fixing paper conveying belt, and continuous paper.

In addition to the tandem type digital color copying machine described above, the present invention can be applied to any image forming apparatus provided with at least an endless belt and a speed detection roll for detecting the rotation speed of the endless belt. It can also be applied to an image forming apparatus.

[0047]

As is apparent from the above description, according to the present invention, the cleaning member removes foreign matter such as toner adhering to the surface of the speed detecting roll so that the outer diameter of the speed detecting roll does not change. Therefore, the rotation speed of the endless belt can be accurately detected for a long time by the speed detection roll.

Further, according to the present invention, the cleaning brush, which is a cleaning member, is selectively set in the contact state and the separated state with respect to the speed detection roll. Therefore, the cleaning brush can be used when the image forming apparatus is not used. It can be separated from the speed detection roll. As a result, it is possible to prevent the cleaning brush from contacting the speed detection roll at all times and causing early deterioration such as sag.

Further, according to the present invention, the cleaning brush is held in a state of being separated from the speed detecting roll during the image forming operation of the image forming apparatus. Therefore, during the image forming operation of the image forming apparatus, the speed detecting roll is held. Is not affected by the load of the cleaning brush and can rotate more accurately. As a result, the image forming apparatus can perform image formation with high accuracy.

[Brief description of drawings]

FIG. 1 schematically illustrates a developing device, a transfer device, a fixing device, and a paper feeding, transporting, and discharging device in a tandem digital color copying machine as an example of an image forming apparatus to which the present invention is applied. It is a figure.

FIG. 2 is a diagram schematically showing a speed detection roll and a cleaning device therefor according to one embodiment of the present invention.

FIG. 3 is a view similar to FIG. 2, showing another embodiment of the present invention.

FIG. 4 is a view similar to FIG. 2 showing still another embodiment of the present invention.

FIG. 5 is a view similar to FIG. 2 showing still another embodiment of the present invention.

[Explanation of symbols]

1 ... Digital color copying machine, 2Y ... Yellow photosensitive drum, 2M ... Magenta photosensitive drum, 2C ... Cyan photosensitive drum, 2K ... Black photosensitive drum, 6 ... Transfer device, 7 ... Transfer belt (endless Belt), 9 ... drive roller,
10 ... Following roller, 17 ... Transfer paper, 21 ... Fixing device, 2
7 ... Speed detection means, 28 ... Encoding roll (E
/ R), 29 ... pinch roll, 30 ... pinch roll, 3
1 ... foreign matter, 32 ... cleaning device, 33 ... cleaning brush, 33a ... roll in which cleaning brush is planted,
34 ... Supporting member, 34a ... Foreign matter reservoir, 35 ... Motor,
36 ... Control device, 37 ... Solenoid, 37a ... Drive shaft,
38 ... Transfer operation detecting means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03G 21/00 118 // B65G 45/18

Claims (6)

[Claims] 1. A predetermined number of rolls that are rotatably supported by a frame, an endless belt that is stretched around the predetermined number of rolls, and a surface that abuts against the endless belt and that rotates the endless belt. In an endless belt of an image forming apparatus, which is provided with at least a speed detection roll for detecting the rotation speed of the endless belt by rotating in conjunction, the surface of the speed detection roll is brought into contact with and cleaned. A cleaning device for a speed detection roll in an endless belt of an image forming apparatus, characterized in that a cleaning member is provided. 2. The cleaning device for a speed detecting roll in an endless belt of an image forming apparatus according to claim 1, wherein the cleaning member is a cleaning brush. 3. The cleaning device for a speed detecting roll in an endless belt of an image forming apparatus according to claim 2, wherein the cleaning brush is made of a conductive material. 4. A roll which can be selectively set in a rotatable state and a fixed state and has the cleaning brush implanted in at least a part of the surface thereof, a motor for rotating the roll, and a motor for rotating the roll. 4. A cleaning device for cleaning a speed detecting roll in an endless belt of an image forming apparatus according to claim 2, further comprising a motor drive control device for driving and controlling the motor so as to rotate at a predetermined interval for a predetermined angle. . 5. The cleaning brush driving means for selectively setting the cleaning brush in a contact state or a separated state with respect to the speed detection roll is provided. A cleaning device for a speed detection roll in an endless belt of the image forming apparatus described in 1. 6. The cleaning brush driving means is controlled so as to set the cleaning brush in the separated state during an image forming operation of the image forming apparatus, and the cleaning brush is moved during a non-image forming operation of the image forming apparatus. The cleaning device for a speed detection roll in an endless belt of an image forming apparatus according to claim 5, further comprising a cleaning brush control unit that controls the cleaning brush driving unit so as to set the contact state.