JP2000112313A - Cleaning device and digital electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cleaning device capable of perfectly cleaning an image carrier by preventing a cleaning roller from rotating together with the image carrier. SOLUTION: This cleaning device is a cleaning device for an image forming device where a developed image is formed on a photoreceptor drum (image carrier) moved endlessly and the photoreceptor drum is reused by cleaning the photoreceptor drum after transferring the developed image. In this case, in the cleaning device 3 equipped with a cleaning blade 4 abutting on the surface of the photoreceptor drum and a cleaning roller 5 positioned on an upstream side in the moving direction of the photoreceptor drum from the abutting position of the blade 4 and rotating in the same direction as the moving direction of the photoreceptor drum and at a lower circumferential speed than that of the photoreceptor drum 1, a rotational load larger than a torque with which the roller 5 is rotated, is applied to the roller 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for cleaning the surface of an image carrier after image transfer with a cleaning blade, and a digital electrophotographic apparatus having the same.

[0002]

2. Description of the Related Art In a conventional image forming apparatus, a cleaning device for cleaning an image carrier such as an electrophotographic photosensitive member is provided with a cleaning blade and an image carrier parallel to the image carrier upstream of the cleaning blade in the image carrier rotation direction. A cleaning roller such as a sponge roller, a brush roller, or a magnetic brush roller (magnet roller) is used as a cleaning auxiliary member provided.

The function of the cleaning roller is to wipe off the transfer residual toner on the image carrier by rubbing with the image carrier, and to supply the toner to the cleaning blade by applying an appropriate amount of toner to the image carrier. No. The toner supplied to the cleaning blade suppresses the sliding force between the cleaning blade and the image carrier, reduces the load acting on the cleaning blade, and acts so that the contact of the cleaning blade is always kept uniform.

As a method of inputting a drive to a cleaning roller, a method of directly inputting a drive from an image carrier using a timing belt or the like has been adopted.

[0005]

However, when a drive is directly input from the image carrier to the cleaning roller, especially in the case of a digital image, the image carrier is used to write an image on a line with a laser on the image carrier. In addition, various vibrations are transmitted, and pitch unevenness is likely to occur in an image.

When a drive from the paper transport motor is input to the cleaning roller, when the cleaning roller is rotated in the forward direction with respect to the image carrier and slower than the image carrier, the cleaning roller moves by the amount of gear backlash. There was a problem of turning around.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a cleaning device capable of preventing the cleaning roller from rotating around the image carrier and completely cleaning the image carrier. An object of the present invention is to provide a digital electrophotographic apparatus provided with the above.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a developed image is formed on an endlessly moving image carrier, and the surface of the image carrier after transfer of the developed image is cleaned. A cleaning blade for contacting the surface of the image carrier, and an image cleaning device that is located upstream of a contact position of the cleaning blade in a moving direction of the image carrier. In a cleaning device provided with a cleaning roller that rotates in the same direction as the carrier moving direction and at a peripheral speed lower than the peripheral speed of the image carrier, a rotational load larger than the torque that the cleaning roller rotates together is applied to the cleaning roller. It is characterized by the following.

According to a second aspect of the present invention, in the first aspect of the present invention, a rotational load is applied to the cleaning roller by a torque limiter.

According to a third aspect of the present invention, in the first aspect of the present invention, a rotational load is applied to the cleaning roller by clamping a shaft of the cleaning roller with a friction plate.

According to a fourth aspect of the present invention, in the first aspect, a rotational load is applied to the cleaning roller by a flywheel provided on a shaft of the cleaning roller.

According to a fifth aspect of the present invention, in the first aspect of the invention, the image carrier is formed of a photosensitive drum or an intermediate transfer member.

According to a sixth aspect of the present invention, there is provided a cleaning blade in contact with the surface of an image carrier, the cleaning blade being located upstream of the contact position of the cleaning blade in the image carrier moving direction and in the same direction as the image carrier moving direction. In a digital electrophotographic apparatus provided with a cleaning device having a cleaning roller rotating at a peripheral speed lower than the peripheral speed of the image carrier, a rotational load larger than the torque that the cleaning roller rotates with the cleaning roller of the cleaning device is provided. It is characterized by the following.

Therefore, according to the present invention, the cleaning roller is provided with a rotational load larger than the torque that the cleaning roller rotates, so that the cleaning roller is prevented from rotating around the image carrier, and the cleaning roller is stabilized. Is ensured, the stable supply of the re-coated toner to the surface of the image carrier becomes possible, and the image carrier can be completely cleaned.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a sectional view of a main part of an image forming apparatus provided with a cleaning device according to the present invention. In FIG. 1, reference numeral 1 denotes a photosensitive drum as an amorphous silicon photosensitive member serving as an image carrier, and around the photosensitive drum 1, a pre-exposure 2, a primary charger 10, an image exposure 1
1, a developing device 12, a post charger 14, a transfer separation charger 13, and a cleaning device 3 according to the present invention are provided. Further, a fixing device 7 having a conveyance belt 15, a fixing roller 8 and a pressure roller 9 is disposed downstream of the photosensitive drum 1 in the transfer material conveyance direction.

Incidentally, a high-voltage power supply (not shown) is connected to the primary charger 10, the developing sleeve 17 of the developing device 12, and the transfer separation charger 13, respectively. The photosensitive drum 1, the developing sleeve 17, and the fixing roller 8 are each provided with a drive motor (not shown), and these can be driven independently.

The maximum image width of the image forming apparatus according to the present embodiment is about 290 mm on the side of A4, and the process speed is 500 mm / sec. In the developing device 12, a developing sleeve 17, which is formed by forming a coating layer of a mixture of phenol resin, graphite and carbon on the surface of an aluminum cylinder having a diameter of 20 mm,
Is driven in the forward direction at a relative speed of 150%, and the distance between the developing sleeve 17 and the photosensitive drum 1 is set to 230 μm. Further, the coating of the toner on the developing sleeve 17 is as follows.
The distance between the developing sleeve and the magnetic blade was set to 280 μm using a magnetic blade, and the frequency
700 Hz, peak-to-peak voltage 1400 V, duty ratio 5
This is performed by applying a superposition of a 0% sine wave and a direct current.

The toner has a negatively charged average particle size of about 9 μm, a main binder of styrene acrylic, a magnetic substance of about 80 parts by weight, a glass containing 4% of strontium titanate and 0.5% of silica as external additives. Transition point about 6
A one-component magnetic toner at 0 ° C. is used, and the tribo of the toner on the developing sleeve 17 is −3 to −12 (μC / g);
The coating amount is 0.6 to 1.3 mg / cm ³ .

As the photosensitive drum 1, an amorphous silicon photosensitive layer having a thickness of about 30 μm formed by glow discharge or the like on an aluminum cylinder having a diameter of 108 mm and a thickness of about 5 mm was used.

The fixing device 7 has a surface layer of about 20 μm fluororesin (PT) on a silicon rubber layer having a thickness of 0.25 mm.
A fixing roller 8 coated with FE) by baking or the like, a 1000 W rated halogen heater 8 a provided inside the fixing roller 8, and a 100 μm-thick fluororesin (PFA) tube on silicon rubber having a diameter of 60 mm and a thickness of 5 mm And a pressure roller 9 covered with the pressure roller.

Further, a planar heating heater 16 of about 80 W is provided inside the photosensitive drum 1 for one round, and the electric power is controlled so that the temperature of the aluminum cylinder becomes 42 ° C.

FIG. 2 is a schematic sectional view of the cleaning device 3, and FIG. 3 is an enlarged detailed view of the cleaning device 3.

As shown in FIG. 2, the cleaning device 3
Has a cleaning blade 4 made of urethane and having a thickness of 2 mm, a cleaning roller 5 having a diameter of 18 mm and eight magnetic poles each having a magnetic flux density of 500 gauss, and a regulating roller 6 having a diameter of 8 mm. The cleaning roller 5
The regulating roller 6 is driven to rotate by the drive from the photosensitive drum 1, and as shown in FIG.
Rotates at a peripheral speed of 10% of the photosensitive drum 1 in the forward direction with respect to the traveling direction of the photosensitive drum 1, and the regulating roller 6 rotates 5% of the cleaning roller 5 in the counter direction with respect to the rotating direction of the cleaning roller 5. It rotates at peripheral speed. The gap between the cleaning roller 5 and the photosensitive drum 1 and the gap between the cleaning roller 5 and the regulating roller 6 are 1.5 mm, respectively.
It is set to 1.9 mm.

The cleaning roller 5 is coated with the untransferred toner regulated by the regulating roller 6. The toner contacts the photosensitive drum 1 while rubbing, so that the toner is coated on the photosensitive drum 1. Is done. And
Thereafter, the cleaning blade 4 installed downstream is
As a result, the surface of the photosensitive drum 1 is cleaned by scraping the toner from above the photosensitive drum 1.

On the other hand, the toner dropped from the cleaning roller 5 into the cleaning casing is
2 and 3 are collected in a waste toner container (not shown).

Next, the drive input will be described with reference to the drive system diagram of FIG.

As described above, the developing sleeve 17, the photosensitive drum 1 and the fixing roller 8 have different driving motors, respectively, and the cleaning roller 5, the regulating roller 6 and the screw 18 in the cleaning device 3 have the transport motor 2 of the main body.
From 0, the rotation is decelerated by a gear train and the drive is input. Because of such a drive input relationship, if the cleaning roller 5 is rotated while the rotation of the photosensitive drum 1 is stopped, the toner on the cleaning roller 5 is scraped off by the photosensitive drum 1 and conveyed. The toner drops on the road. Therefore, the sequence is incorporated in a configuration in which the photosensitive drum 1 rotates when the cleaning roller 5 rotates. Further, even if a serviceman reversely rotates the photosensitive drum 1 by hand, the same thing occurs. Therefore, a one-way rotating clutch is arranged in the drive train of the gear of the photosensitive drum 1 so that the photosensitive drum 1 is It can be rotated only in the direction.

In order to input the rotation to the cleaning roller 5 in the drive train as shown in FIG. 4, the rotation speed is reduced through a number of gears having a backlash (about 0.15 in the case of the module 1). Then, it is necessary to input a drive to the cleaning roller 5.

As shown in FIG. 3, the cleaning roller 5 rotates at a peripheral speed of 10% of the photosensitive drum 1 in a forward direction with respect to the traveling direction of the photosensitive drum 1, and the photosensitive roller 1 and the cleaning roller 5 are rotated. When a small amount of toner accumulates below the cleaning roller 5, the cleaning roller 5 normally rotates at a peripheral speed of 10% of that of the photosensitive drum 1, but the frictional force between the photosensitive drum 1 and the cleaning roller 5 increases. When the cleaning roller 5 rises due to the toner interposed therebetween, the cleaning roller 5 rotates with the backlash of the gear train at the peripheral speed of the photosensitive drum 1, and then the cleaning roller 5
Stops for a moment and stable rotation cannot be guaranteed.

Further, in order to measure the rotating force,
The rotation of the cleaning roller 5 is stopped, and the photosensitive drum 1 is stopped.
As a result of measuring the entrainment force of the cleaning roller 5 when rotating only the cleaning roller 5, the cleaning roller 5 was entrained with a torque of 300 g · cm.

Therefore, in the present embodiment, a torque limiter 22 capable of generating a load (450 g · cm) larger than the frictional force (torque) is mounted on the gear 21 of the cleaning roller 5 as shown in FIG. By directly meshing, the cleaning roller 5 is prevented from rotating together with the photosensitive drum 1. As a result, stable rotation of the cleaning roller 5 is guaranteed, stable supply of the re-coated toner to the surface of the photosensitive drum 1 is possible, and complete cleaning of the photosensitive drum 1 is realized.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG.

In this embodiment, as in the first embodiment, the rotational force of the cleaning roller caused by the frictional force between the photosensitive drum and the cleaning roller due to the toner remaining between the photosensitive drum and the cleaning roller is smaller than the rotational force of the cleaning roller. As shown in FIG. 6, friction plates 22a and 22b are arranged on the outer periphery of a shaft 24 of the cleaning roller so that a large load is applied, and the outside of these friction plates 22a and 22b is sandwiched between leaf springs 23 and rotated by the cleaning roller. I try to give a load. As a result, the rotation of the cleaning roller is prevented, and the same effects as those of the above embodiment can be obtained in this embodiment.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG.

In the present embodiment, as shown in the drive system diagram of FIG. 7, a flywheel 25 is provided on the shaft 24 of the cleaning roller 5 to apply a rotational load to the cleaning roller 5 to move the cleaning roller 5. In this embodiment, the same effects as in the first embodiment can be obtained.

[0037]

As is clear from the above description, according to the present invention, the cleaning roller is provided with a rotational load larger than the torque that the cleaning roller rotates, so that the cleaning roller rotates with the image carrier. As a result, stable rotation of the cleaning roller is assured, stable supply of the re-coated toner to the surface of the image carrier becomes possible, and the effect of completely cleaning the image carrier is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an image forming apparatus including a cleaning device according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of the cleaning device according to the first embodiment of the present invention.

FIG. 3 is an enlarged detailed view of the cleaning device according to the first embodiment of the present invention.

FIG. 4 is a drive system diagram of the image forming apparatus including the cleaning device according to the first embodiment of the present invention.

FIG. 5 is a front view of the cleaning device according to the first embodiment of the present invention.

FIG. 6 is a front view of a cleaning device according to a second embodiment of the present invention.

FIG. 7 is a drive system diagram of an image forming apparatus including a cleaning device according to Embodiment 3 of the present invention.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum (image carrier) 3 cleaning device 4 cleaning blade 5 cleaning roller 20 torque limiter 22a, 22b friction plate 23 leaf spring 24 cleaning roller shaft 25 flywheel

Claims (6)

[Claims] 1. A cleaning device for an image forming apparatus, wherein a developed image is formed on an image carrier that moves endlessly, the surface of the image carrier after transfer of the developed image is cleaned, and the image carrier is reused. A cleaning blade that contacts the surface of the image carrier, and a peripheral speed that is located upstream of the contact position of the cleaning blade in the image carrier movement direction, is in the same direction as the image carrier movement direction, and is slower than the peripheral speed of the image carrier. A cleaning device, comprising: a cleaning roller that rotates with a cleaning roller, wherein a rotation load larger than a torque that the cleaning roller rotates is applied to the cleaning roller. 2. The cleaning device according to claim 1, wherein a rotational load is applied to the cleaning roller by a torque limiter. 3. The cleaning roller according to claim 1, wherein a rotation load is applied to the cleaning roller by sandwiching a shaft of the cleaning roller with a friction plate.
A cleaning device as described. 4. The cleaning roller according to claim 1, wherein a rotational load is applied to the cleaning roller by a flywheel provided on a shaft of the cleaning roller.
A cleaning device as described. 5. The cleaning device according to claim 1, wherein the image carrier is a photosensitive drum or an intermediate transfer member. 6. A cleaning blade in contact with a surface of an image carrier, and a cleaning blade positioned upstream of the abutment position of the cleaning blade in the image carrier movement direction and in the same direction as the image carrier movement direction and around the image carrier. A digital electrophotographic apparatus including a cleaning device having a cleaning roller that rotates at a peripheral speed lower than a speed, wherein a rotational load greater than a torque that the cleaning roller of the cleaning device entrains is applied to the digital electrophotographic device. Electrophotographic equipment.