JP2002123126A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a brush fiber from being largely tilted and coming into contact with an electrifying roller even when space between the electrifying roller and the brush fiber is small by arranging a bristle tilt preventing member at the end on the downstream side of a memory removing brush for removing toner memory remaining on a photoreceptor drum. SOLUTION: The bristle tilt preventing member 28 constituted of an elastic body having insulating property is arranged at the end on the downstream side of the supporting body 26 of the memory removing brush 25 in a device provided with the photoreceptor 21, the brush type electrifying roller 22 and the memory removing brush 25 as one unit. Then, the edge part of the brush fiber 27 is held so as not to come into contact with the roller 22 by preventing the fiber 27 from being largely tilted by using the member 28 when the fiber 27 comes into contact with the drum 21 and is tilted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a memory removing brush which is disposed on a photoreceptor of an image forming apparatus, removes a memory of an image remaining on the surface of the photoreceptor after transferring a toner image to paper or the like. .

[0002]

2. Description of the Related Art In an image forming apparatus configured as a facsimile machine, an electrophotographic copying machine, or a multifunction machine having a plurality of functions, an image forming means using an electrophotographic system is provided to form a toner image formed on a photosensitive member. Is transferred to paper as a recording medium and fixed to create a copy. In the image forming apparatus, a charging device, an exposure unit, a developing device, a transfer device, and a cleaning device are arranged on a photosensitive member. Then, after uniformly charging the photosensitive member by a charging unit, the exposure unit irradiates image light to form an electrostatic latent image, and toner is supplied to the electrostatic latent image from a developing device. The toner image is made visible as a toner image, and the toner image is transferred to paper. After the transfer of the toner image onto the sheet, the toner image memory remaining on the photoreceptor is removed by a cleaning device and used for forming the next image.

As the charging member provided in the image forming apparatus, a charging corotron is generally used in many cases.
When a member that performs high-pressure discharge such as the corotron is used, there is a problem that ozone is generated. Therefore, as a measure against the ozone in the discharge member, a member that uses a roller or a brush roller having conductivity and has a function of directly contacting the photoreceptor to perform charging is used. In addition, without using a cleaning device for the photoconductor, an image using a cleanerless mechanism in which a toner or the like remaining after transferring a toner image onto paper is collected and reused by a developing device. A forming apparatus may be used.

In the cleaner-less type apparatus, a toner brush remaining on a photosensitive member and a conductive brush or brush roller as a memory removing member are removed.
The one to which a positive voltage is applied is brought into contact. Then, an action of disturbing the toner memory remaining after being attached to the photoconductor and an action of weakening the adhesion of the toner to the photoconductor by applying a positive bias voltage and uniformly dispersing the toner on the photoconductor are provided. After that, a function of uniformly charging the surface of the photoreceptor by a brush roller type charger is applied, a latent image is formed by a writing device in an exposure unit, and then a toner supplied from a developing unit is adhered to the toner. Form an image. At the same time as the formation of the toner image, the residual toner dispersed on the photoconductor was collected by a developing roller of a developing device, mixed with newly supplied toner, and mixed again to form a toner image. It is configured to supply toner. In addition, the brush roller-shaped charger uses a brush roller made of conductive fiber, and its shaft is connected to a negative voltage applying means, and the bristles of the brush rub against the surface of the photoreceptor. Thus, the surface of the photoreceptor can be uniformly charged.

[0005]

In the cleanerless image forming apparatus, a photosensitive member, a charging member and a memory removing member are combined to constitute one photosensitive member unit, and a developing unit is provided for the photosensitive member unit. Units are combined and arranged in an image forming unit. In the photoconductor unit, a photoconductor and a charger,
The life of the memory removing member is substantially the same, and when the life of the photoconductor unit is reached, the photoconductor unit is replaced. In the photoreceptor unit, the life of the photoreceptor is configured to have a performance of about 10,000 to 15,000 sheets, but the life of the photoreceptor tends to be longer. In accordance with the life of the photoconductor, a brush-shaped member such as a memory removing member has a longer life than the photoconductor.

In general, since the size of an image forming apparatus tends to be reduced, there is generally a demand for the photoreceptor drum and a photoreceptor unit incorporating the same. However, when the photoconductor drum is configured to have a small diameter, the distance between the charging roller disposed with respect to the photoconductor drum and the brush as the memory removing member is reduced, and the end of the brush fiber of the memory removing brush is reduced. When the object is rubbed against the photosensitive drum and falls down, a state in which the object comes into contact with the charging roller easily occurs. A positive bias is applied to the charging roller, and a negative bias is applied to the memory removing brush, so that the hair of the memory removing brush falls on the charging roller, and it is avoided that both members come into contact. There must be. However, it is an indispensable requirement that the tip of the bristles of the memory removing brush be in contact with the surface of the photosensitive drum for a predetermined length to achieve the effect of removing the memory. Therefore, it is required to set the length of the bristles (fibers) of the brush of the memory removal brush as a predetermined value, and the brush fibers fall down,
The phenomenon that the hairs at the ends approach the charging roller is inevitable, and the danger of the two members coming into direct contact is increasing.

The present invention avoids the problem that the fibers (hairs) of the brush-like memory removing member come into contact with the charging roller to which a reverse bias is applied. It is an object of the present invention to provide a device that can prevent the brush fibers from falling significantly toward the charging roller by disposing them.

[0008]

According to the present invention, there is provided a photoconductor, a charging member for charging the photoconductor, an exposure unit for forming an electrostatic latent image on the charged photoconductor surface, and a photoconductor on the photoconductor surface. The present invention relates to an image forming apparatus including a developing device for developing an electrostatic latent image, a transfer member for transferring a toner image developed on a photoconductor to a recording medium, and a memory removing member for removing a memory of the toner image on the photoconductor. . The invention according to claim 1 of the present invention is characterized in that the memory removing member is configured as a brush member, and a hair fall prevention member is provided on the charging member side of the memory removing member. The invention according to claim 2 is characterized in that the hair fall prevention member is a sheet-like member made of an insulating material.
The invention according to claim 3 is characterized in that the hair fall prevention member is attached to a sheet metal portion of a base of the memory removing brush.

With the above-described structure, even if the bristles (fibers) of the memory removing brush are rubbed against the photosensitive drum and fall to the side of the charging roller as the charging member, the end of the memory removing brush can be obtained. The hair fall prevention member provided on the charging member side of the portion can prevent the fibers from being greatly collapsed and can prevent the fibers from approaching the charging roller as the charging member. Therefore, in the case where the photosensitive drum has a small diameter, even if the charging roller and the memory removing brush are arranged close to each other, the fibers of the memory removing brush can be prevented from contacting the charging roller. Even if bias voltages of opposite polarities are applied, it is possible to prevent inconvenience caused by contact between the two members.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the apparatus of the present invention will be described with reference to the illustrated example. In the example shown in FIG. 1, the developing device and the photosensitive drum are each configured as a unit, and
1 shows a case where an image recording apparatus of an image forming apparatus is configured by combining three units, and the image recording apparatus is provided in an image recording apparatus such as a facsimile apparatus and a copying machine. The apparatus shown in FIG. 1 is mounted as a combination of two units, a developing unit 10 and a photoreceptor unit 20, on the main body of the image recording apparatus. ing. In the developing unit 10, the toner is sent out by rotating the agitator 12 provided in the toner container 11 containing the toner in the clockwise direction (the direction of the arrow in the figure). The toner sent from the toner container 11 by the agitator 12 through the communication port 11 a is exposed at a position facing the photosensitive drum 21 via the supply roller 13 and the developing roller 14.

In the developing unit 10, the toner sent from the toner container 11 toward the supply roller 13 is supplied between the two rollers by rotating the supply roller 13 and the developing roller 14 in the same direction. And is electrostatically attached to the surface of the developing roller 14. The toner adhered to the developing roller 14 is formed as a thin layer having a predetermined thickness by the layer thickness regulating member 15 and is exposed at a position corresponding to the photosensitive drum 21 to form the photosensitive drum 21. The toner image is attached to the electrostatic latent image, and a toner image is formed on the surface of the photoconductor.

In a photoconductor unit 20 disposed with respect to the developing unit 10, a writing device 23 and a charging roller 2 as a charging member are provided for a photoconductor drum 21.
2. The memory removing member 25 composed of a brush and the transfer roller 24 are arranged. Then, with the photoconductor unit 20 mounted on the image recording unit, the photoconductor drum 2
1 is positioned with respect to the transfer roller 24 disposed at a fixed position of the main body frame and the developing roller 14 of the developing device 10. The illustrated photoconductor unit 20
In this example, unlike a general image recording apparatus, the apparatus is configured as a cleaner-less apparatus without a cleaning apparatus. In this type of apparatus, the toner image formed on the photosensitive drum is transferred to paper, and then the toner remaining on the drum surface is disturbed by the biased memory removing member 24, and the disturbed toner is transferred to the developing device. It is returned, mixed with the newly supplied toner, and used again.

In the photoconductor unit 20, a charging roller 22 for uniformly charging the photoconductor drum 21 is disposed downstream of the memory removing brush 25. The charging roller 22 includes a brush roller. The charging roller 22 is also rotated clockwise in conjunction with the operation of rotating the photosensitive drum 21 clockwise in FIG. Charging roller 2 for peripheral speed of 21
The peripheral speed of 2 is set to about 2 to 3 times. And
The operation of the brush of the charging roller 22 sliding at a high speed on the surface of the photosensitive drum 21 and the action of applying a predetermined voltage to the charging roller 22 uniformly charge the surface of the photosensitive drum 21 to expose For the formation of an electrostatic latent image in the image forming section. The transfer unit is located on the upstream side of the memory removing brush 25 with respect to the rotation direction of the photosensitive drum 21, and the exposure unit by the charging roller 22 and the writing device 23 is located on the downstream side of the memory removing brush 25. You.

FIGS. 2 and 3 show a charging roller 22 disposed on a photosensitive drum 21 and the charging roller 22.
The relationship between the memory removal brush 25 disposed on the upstream side in the rotation direction of the photosensitive drum 21 and the configuration of the memory removal brush 25 will be described. Memory removal brush 25 for removing memory remaining on photoconductor drum 21
As shown in the figure, a brush fiber 27 in which long hair fibers are planted is provided on a support 26 attached to a photoreceptor unit frame. As the brush fiber 27, for example, a soft fiber such as conductive rayon is used, and the brush fiber is made of the same material as that used for a conventional memory removing brush or roller. In the memory removal brush 25 made of the conductive fiber, the positive bias voltage is applied to the support 26 made of a conductive member such as a metal to adhere to the photosensitive drum 21. The effect of weakening the adhesion of the remaining toner is exerted.

In the memory removing brush 25 in which the brush fibers 27 are provided on the support 26, a hair fall prevention member 28 is provided on the downstream side of the support 26, and the hair fall prevention member 28 is provided.
Are made of a member having insulating elasticity. As the hair fall prevention member 28, for example, a sheet-like member formed of PET (polyethylene terephthalate) resin or the like can be used.
Is attached to the downstream side of the support 26. The tip of the hair fall prevention member 28 has a brush fiber 27
The length of the brush fiber 27 is larger than the length of the brush fiber 27. The length of the brush fiber 27 is larger than the length of the brush fiber 27. Be able to stop falling.

As described above, in the memory removing brush 25 in which the hair fall prevention member 28 is disposed downstream of the support 26, the photosensitive drum 21 is rotated clockwise as shown in FIG. The distal end of the brush fiber 27 in contact with the body drum 21 is slid so as to fall down, and the memory removing operation is performed. At this time, the brush fibers 27 that fall along the surface of the photoconductor drum 21 try to cause the distal end of the brush fiber 27 to fall in the rotation direction of the photoconductor drum. So
It is prevented from protruding largely toward the charging roller 22 side.
Since the hair fall prevention member 28 is made of an elastic body, it is pushed by the brush fibers 27 that fall down, and a slight bending force is applied to the charging roller 22 side. However, as compared with the case where the hair fall prevention member 28 is not provided, the amount by which the brush fibers 27 and the hair fall prevention member 28 fall is relatively small. Can be prevented from occurring.

An image forming apparatus in which the developing unit 10 is combined with a photosensitive unit 20 is incorporated in the image forming apparatus as shown in FIG. Can be transferred to In the image forming section of the image forming apparatus 1 shown in FIG. 4, a sheet feeding section from a sheet feeding tray 2 is provided at a lower portion of the apparatus, and an image forming section using an electrophotographic method is arranged at an upper portion. In the paper feed section, paper is fed one by one by a paper feed roller 3 disposed on a paper feed tray 2, and the paper is conveyed by conveyance roller devices 5 and 6 along a paper conveyance path 4 to transfer a toner image. I send it to the department. Then, the toner image formed on the photosensitive drum 21 is transferred to a sheet, and the fixing device 7 including a heat roller 7a and a pressure roller 7b is transferred.
And is discharged toward the discharge tray by the discharge roller device 8. In the image forming apparatus,
The paper transport device can use a conventionally known configuration, and is intended for an image forming unit in which the developing unit 10 and the photoconductor unit 20 are arranged in combination.

In the embodiment of the memory removing brush, the brush fiber constituting the memory removing brush can be made of the same material as that of a conventional brush provided in an image forming apparatus. Can be formed according to the voltage applied to the memory removal brush. Further, conditions such as an arrangement interval between the memory removing brush and the charging roller can be arbitrarily set according to the size diameter of the photosensitive drum, the size of the photosensitive unit, and the like. further,
As the hair fall prevention member provided in the memory removal brush, a sheet-like material using any conventionally known plastic material is used as long as it has insulation and elasticity and can withstand long-time use. be able to.

[0019]

The apparatus according to the present invention is constructed as described above. Therefore, even if the hair (fiber) of the memory removing brush is rubbed against the photoreceptor drum and falls down to the charging roller side, the memory can be used. The bristle fall prevention member provided on the charging roller side at the end of the removing brush prevents the fibers from being greatly collapsed, and can prevent the fibers from approaching the charging roller. Therefore, even when the charging roller and the memory removing brush are arranged close to each other when the photosensitive drum is made to have a small diameter,
Since the fibers of the memory removing brush can be prevented from coming into contact with the charging roller, it is possible to prevent the occurrence of inconvenience due to the contact between the two members even if the two members are applied with bias voltages of opposite polarities.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example in which an image forming unit is configured by combining two units.

FIG. 2 is an explanatory diagram of a memory removing brush arranged on a photosensitive drum.

FIG. 3 is an explanatory diagram of an operation state of a memory removal brush.

FIG. 4 is an explanatory diagram illustrating a configuration of an image forming apparatus to which the unit in FIG. 1 can be applied;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 image forming apparatus, 7 fixing device, 10 developing unit, 11 toner container, 14 developing roller, 20 photoconductor unit, 21 photoconductor drum, 22 charging roller, 23 writing device,
24 transfer roller, 25 memory removal brush,
26 support, 27 brush fiber, 28 hair fall prevention member.

Claims (3)

[Claims] A photoconductor, a charging member for charging the photoconductor, an exposure unit for forming an electrostatic latent image on the charged photoconductor surface, and a developing device for developing the electrostatic latent image on the photoconductor surface An image forming apparatus comprising: a transfer member that transfers a toner image developed on a photoconductor to a recording medium; and a memory removal member that removes a memory of the toner image on the photoconductor. An image forming apparatus, wherein a hair fall prevention member is provided on the charging member side of the memory removing member. 2. The image forming apparatus according to claim 1, wherein the hair fall prevention member is a sheet member made of an insulating material. 3. The image forming apparatus according to claim 1, wherein the hair fall prevention member is attached to a sheet metal portion of a base of the memory removing brush.