JPH0862948A - Contact type electrifying device - Google Patents

Abstract

PURPOSE: To remove toner or a foreign matter adhering to the surface of an electrifying roller over a long term without damaging the electrifying roller by using a cleaning roller whose outer peripheral part coming in contact with the electrifying roller is made of porous sponge. CONSTITUTION: A cleaning roller 103 cleaning the electrifying roller 102 is made of the porous sponge member and driven to be rotated in a direction rotating with the roller 102. Since the cleaning roller 103 is made of the porous sponge member, aggresivity against the roller 102 is low so as to prevent a failure that the roller 102 is damaged. The cleaning roller 103 is formed in a roller shape, so that area to scavenge the adhering foreign matter is widened. Therefore, the life of the cleaning roller 103 is prolonged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type charging device for uniformly charging a photosensitive member by bringing a charging roller into contact therewith, and more particularly to removing toner or foreign matter adhering to the surface of the charging roller. The present invention relates to a contact type charging device having a cleaning member.

[0002]

2. Description of the Related Art In a conventional contact type charging device, charging is performed by bringing a charging roller into contact with a photosensitive member with a predetermined pressing force. There was the inconvenience that it adhered foreign substances and was easily soiled. Therefore, as a solution to this problem, cleaning is disclosed as disclosed in "Charging device" of Japanese Patent Application Laid-Open No. 3-101768 and "Contact charging device and image forming apparatus" of Japanese Patent Application Laid-Open No. 4-60660. An apparatus has been proposed in which a member removes toner or foreign matter adhering to the surface of the charging roller.

The "charging device" of Japanese Patent Laid-Open No. 3-101768 has a construction in which a cleaning member is a sponge member and the sponge member is fixed to a support plate. Therefore, the foreign matter adhering to the charging roller can be removed reliably at low cost. Further, the cleaning member is arranged so that the perpendicular line from the rotation center of the charging roller to the mounting support plate of the cleaning member and the contact surface between the charging roller and the cleaning member are coincident or have an appropriate gap. Therefore, even if the cleaning member is pressed against the charging roller for a long time and is repeatedly used, it is possible to prevent the cleaning member from being peeled off or torn from the mounting support surface.

The "contact charging device and the image forming apparatus" disclosed in Japanese Patent Laid-Open No. 4-60660 uses a brush roller as a cleaning member and attaches the material to the charging roller in a charging series with the charging roller. The foreign matter on the charging roller is removed by bringing the brush roller and the charging roller into contact with each other, and having a polarity opposite to the polarity of the foreign matter.

[0005]

However, according to the "charging device" of Japanese Patent Laid-Open No. 3-101768 mentioned above,
Since the contact area between the sponge member used as the cleaning member and the charging roller is small, the area for collecting the adhering foreign matter on the sponge member is small, and the sponge member is easily soiled, which shortens the life of cleaning performance. there were.

Further, according to the "contact charging device and the image forming apparatus" disclosed in Japanese Patent Laid-Open No. 4-60660, the brush roller, which is a cleaning member, rubs the surface of the charging roller with a peripheral speed difference. There is a problem that the surface of the charging roller is damaged by the brush of the brush roller.

The present invention has been made in view of the above, and it is an object of the present invention to remove the toner or foreign matter adhered to the surface of the charging roller for a long period of time without damaging the charging roller.

[0008]

In order to achieve the above object, the present invention provides a contact type charging device according to claim 1, wherein a contact type charging roller for charging a photosensitive member and a surface of the charging roller are provided. In the contact type charging device having a cleaning member for removing the adhered toner or foreign matter, the cleaning member is a cleaning roller having an outer peripheral portion in contact with the charging roller formed of a porous sponge layer.

Further, in the contact type charging device according to a second aspect of the invention, the cleaning roller is arranged such that the amount (t) of biting into the charging roller is in the range of 0 <t <0.5. It is a thing.

Further, the contact type charging device according to claim 3 is
The cleaning roller is rotationally driven in a direction in which the cleaning roller rotates together with the charging roller.

Further, the contact type charging device according to claim 4 is
When the charging roller and the cleaning roller are independently driven, and the peripheral speed of the charging roller is V1 and the peripheral speed of the cleaning roller is V2, V2 = V1 × (1 to 1) .4).

[0012]

According to the contact type charging device of the present invention (claim 1), the toner or the foreign matter adhering to the surface of the charging roller is removed by the cleaning roller having the outer peripheral portion in contact with the charging roller made of a porous sponge member. To do.

Further, in the contact type charging device of the present invention (claim 2), the cleaning roller is attached so that the biting amount (t) of the cleaning roller into the charging roller is 0 <t <0.5. To reduce the load on the charging roller.

Further, in the contact type charging device of the present invention (claim 3), the cleaning roller is rotationally driven in the direction in which the cleaning roller is rotated together with the charging roller, so that the occurrence of slip between the cleaning roller and the charging roller is prevented. It

In the contact type charging device of the present invention (claim 4), the peripheral speed of the charging roller is V1, the peripheral speed of the cleaning roller is V2, and V1 and V2 are V2 = V1 * (1
By maintaining the relationship of 1.4), the contact area of the cleaning roller with the charging roller is increased, and the cleaning performance is improved. Further, the occurrence of slip between the cleaning roller and the charging roller is prevented.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where the contact type charging device of the present invention is applied to a copying machine will be described in detail as an embodiment with reference to the drawings.

First, the operation of the image forming system of the copying machine will be described with reference to FIG. FIG. 1 is an explanatory diagram showing a part of the configuration of an image forming system in a copying machine of the present embodiment, in which a photoconductor 1 as an image carrier for forming an electrostatic latent image and a toner image.
01, a contact type charging roller 102 for charging the photoconductor 101, and a cleaning roller 103 for removing toner or foreign matter adhering to the surface of the charging roller 102.
A developing unit 104 for visualizing the electrostatic latent image formed on the photoconductor 101, and a toner image for transferring the toner image formed on the photoconductor 101 to recording paper (not shown). The transfer portion 105a and the recording paper after the transfer processing are attached to the photosensitive member 101.
And a cleaning blade 106 for removing the residual toner on the surface of the photoconductor 101 after the separation process, and a discharge lamp 107 for discharging the residual potential of the photoconductor 101.

The reference numeral 104a designates a developing roller for guiding the toner to the photosensitive member 101 in the developing unit 104.

Now, referring to FIG. 2, the charging roller 10
2 will be described. The charging roller 102 has a structure in which a conductive elastic member is wound around a metal cored bar,
As shown in FIG. 2, bearings 202 are fitted on both ends of the cored bar 201, and the bearings are pressed against the photoconductor 101 by the pressing member 203 with an appropriate pressing force.
Alternatively, it is driven by using driving means. Then, a voltage is applied to the cored bar portion 201 of the charging roller 102 to apply the photosensitive member 101.
Charge the surface.

The operation of the image forming system having the above configuration will be described. First, the charge removal lamp 107
1, the surface potential of the photoconductor 101 is 0 to -1.
The reference potential is 50V. Next, a charge is applied to the photoconductor 101 by the charging roller 102, and the photoconductor 101 is charged.
Has a surface potential of around -1100V. The photoreceptor 101 charged to -1100V is irradiated with laser light emitted from a laser diode (not shown).

Here, the laser light will be described.
First, digital recording image information sent from an image processing unit (not shown), which is a known technique, is received by a line driver circuit (not shown) and amplified by a laser driver circuit (not shown). . The digital recording image information is a 1-bit (recording / non-recording) binary signal per pixel,
A laser driver circuit activates a laser diode (not shown) to emit light in response to the binarized signal. The laser light emitted from the laser diode is, as described above, the photosensitive member 1
The image is irradiated onto 01.

On the surface of the photosensitive member 101, the surface potential of a portion (image portion: hereinafter referred to as an image portion) irradiated with light (laser light) is 0 to -290 V, which is a non-image portion not irradiated with light. Part (background) surface potential is -1100
V remains, and an electrostatic latent image is formed on the surface of the photoconductor 101. The electrostatic latent image is toner-developed by the developing unit 104, and a toner image is formed on the surface of the photoconductor 101.

In the developing unit 104, since the developing roller 104a is biased at about -800V, the toner in the developing unit 104 adheres to the image portion (surface potential 0 to -290V), and the non-image portion. It does not adhere to (surface potential-1100V).

Along with the formation of the toner image on the surface of the photosensitive member 101, the recording paper is conveyed from a paper supply unit (not shown). The recording paper is conveyed at a timing when the image leading end of the toner image and the leading end of the recording paper coincide with each other at the position of the transfer unit 105a. The toner image formed on the surface of the photoconductor 101 is transferred onto the conveyed recording paper by the transfer unit 105a, and the recording paper after the transfer processing is separated from the photoconductor 101 by the separation unit 105b. The recording paper separated from the photoconductor 101 is sent to a fixing unit (not shown), and the transferred toner image is fused to the recording paper by heat and pressure and discharged as a copy to the outside of the apparatus.

On the other hand, the residual toner remaining on the photoconductor 101 is scraped off from the photoconductor 101 by a cleaning blade 106 in a cleaning unit (not shown), so that the photoconductor 101 is in a toner-free state and a copying operation is performed. Simultaneously with the end, the drive source on the main body side operates in reverse and stops. After that, the process moves to the next imaging process again.

Next, the operation of the cleaning roller 103, which is a feature of the present invention, will be described. Charging roller 102
The roller-shaped cleaning roller 103 for cleaning the roller is made of a porous sponge member and is configured to be rotationally driven in the direction in which the charging roller 102 is rotated. Since the cleaning roller 103 is made of a porous sponge member, it is less aggressive to the charging roller 102 and can prevent the charging roller 102 from being damaged. Also, the cleaning roller 103
Since the roller has a roller shape, the area for collecting the adhering foreign matter can be increased, so that the cleaning roller 1
The life of 03 can be extended.

In this embodiment, as shown in FIG. 3, the amount (t) of the cleaning roller 103 biting into the charging roller 102 is set to 0 <t <0.5. Here, when the bite amount (t) is t = 0, there is almost no cleaning effect, and when t ≧ 0.5, the bite amount is too large and the film is rubbed too easily, and filming easily occurs, and charging is performed. Roller 10
The load on 2 increases. Therefore, by setting the bite amount (t) to 0 <t <0.5, good cleaning performance can be obtained.

Further, the cleaning roller 103 is configured to be driven in a direction in which the cleaning roller 103 is rotated together with the charging roller 102 by using a driving means (not shown). As a result, it is possible to prevent the cleaning roller 103 from becoming non-rotating due to slippage or the like. Therefore, the following problems can be prevented. That is, the cleaning roller 10
3 becomes non-rotating, the cleaning roller 10
It is possible to prevent the problem that the charging roller 102 cannot be sufficiently cleaned (cleaning failure) because there is only one contact point of the charging roller 102 with the charging roller 102.

Further, in the structure in which the charging roller 102 and the cleaning roller 103 are driven respectively, the peripheral speed of the charging roller 102 is V1, and the cleaning roller 10
The peripheral speed of 3 is V2, and V1 and V2 are V2 = V1 × (1
To 1.4) are maintained, a peripheral speed difference is provided between the charging roller 102 and the cleaning roller 103, the contact area between the charging roller 102 and the cleaning roller 103 is increased, and cleaning performance is improved. Can be made. The relationship between V1 and V2 is V2
When ≧ V1 × 1.5, the driving torque to the charging roller 102 and the cleaning roller 103 increases, and the drive transmission means such as gears causes tooth jumps and the like.

FIG. 4 shows an embodiment of a method for driving the charging roller 102 and the cleaning roller 103. The bearing 202 is used in which the distance between the charging roller 102 and the cleaning roller 103 is controlled so that the biting amount between the charging roller 102 and the cleaning roller 103 is 0 <t <0.5.
The peripheral speed (V1) of the charging roller 102 and the peripheral speed (V2) of the cleaning roller 103 are V2 = V1 × (1-1.
The cleaning roller drive gear 204 and the cleaning roller driven gear 2 set to maintain the relationship of 4).
05, and the bearing 202 to the pressing member 203
To press the charging roller 102 against the photoconductor 101.

The charging roller 102 includes a charging roller driving gear 206 mounted on the photosensitive member 101 and a charging roller driven gear 20 mounted on the charging roller 102.
It is configured to be driven at the same speed by 7.

[0032]

As described above, according to the contact type charging device of the present invention (Claim 1), the surface of the charging roller is formed by the cleaning roller in which the material of the outer peripheral portion in contact with the charging roller is a porous sponge member. To remove the toner or foreign matter adhering to the surface, without damaging the charging roller,
In addition, it is possible to remove the toner or foreign matter attached to the surface of the charging roller for a long period of time.

Further, in the contact type charging device of the present invention (claim 2), the cleaning roller is attached so that the biting amount (t) of the cleaning roller into the charging roller is 0 <t <0.5. The load on the charging roller can be reduced and good cleaning performance can be obtained.

Further, in the contact type charging device of the present invention (claim 3), the cleaning roller is rotationally driven in the direction in which the cleaning roller is rotated together with the charging roller, so that the occurrence of slip between the cleaning roller and the charging roller is prevented. ， Can prevent cleaning failure of the charging roller.

In the contact type charging device of the present invention (claim 4), the peripheral speed of the charging roller is V1, the peripheral speed of the cleaning roller is V2, and V1 and V2 are V2 = V1 * (1
By maintaining the relationship of 1.4), the contact area of the cleaning roller with the charging roller is increased, and the cleaning performance is improved. Further, the occurrence of slip between the cleaning roller and the charging roller can be prevented, and cleaning failure of the charging roller can be prevented.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a part of the configuration of an image forming system in a copying machine of this embodiment.

FIG. 2 is an explanatory diagram showing a configuration of a peripheral portion of a charging roller.

FIG. 3 is an explanatory diagram showing a relationship between biting amounts of a charging roller and a cleaning roller.

FIG. 4 is an explanatory diagram showing a configuration of drive systems of a photoconductor, a charging roller, and a cleaning roller.

[Explanation of symbols]

102 charging roller 103 cleaning roller

Claims (4)

[Claims] 1. A contact type charging device having a contact type charging roller for charging a photoconductor and a cleaning member for removing toner or foreign matter adhering to the surface of the charging roller, wherein the cleaning member is the charging unit. A contact-type charging device, which is a cleaning roller having an outer peripheral portion in contact with the roller formed of a porous sponge layer. 2. The contact according to claim 1, wherein the cleaning roller is arranged so that a biting amount (t) into the charging roller is in a range of 0 <t <0.5. Charging device. 3. The contact type charging device according to claim 1, wherein the cleaning roller is rotationally driven in a direction in which the cleaning roller rotates together with the charging roller. 4. The charging roller and the cleaning roller are independently driven, and V2 = V1 where V1 is the peripheral speed of the charging roller and V2 is the peripheral speed of the cleaning roller. 4. The contact type charging device according to claim 1, wherein the relationship is x (1 to 1.4).