JP2543351B2 - Electrostatic brush cleaning device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for an electrophotographic copying machine, and more specifically, to a surface of a photoconductor using an electrostatic attraction force using a conductive fiber planting brush. The present invention relates to an electrostatic brush cleaning device for cleaning.

2. Description of the Related Art An electrostatic brush cleaning device is configured as shown in FIG. 1, and a conductive brush 17 is provided in a housing 15 so as to rub against an image carrier (hereinafter referred to as a photoconductor) 1. While bringing the toner collecting roll 19 into contact with the conductive brush 17, the scraper 21 is brought into contact with the toner collecting roll 19, a voltage is applied to the conductive brush 17, and the toner collecting roll 19 has the same polarity and a higher voltage. While applying
A pre-cleaning corotron 13 and a pre-cleaning lamp 13 'are provided in front of the housing 15 in the rotating direction, and a DC voltage is first applied to the remaining toner image (hereinafter referred to as residual toner) transferred from the photoconductor 1 onto the sheet. The pre-cleaning corotron 13 is charged to a single polarity. In this conventional example, (-) is charged.

Next, the conductive brush 17 to which a DC voltage having a polarity opposite to that of the pre-cleaning corotron 13 is rubbed against the photoconductor 1 to clean the residual toner on the photoconductor 1.

The cleaned residual toner is transferred from the conductive brush 17 to the toner collecting roll 19, separated by the scraper 21, dropped on the hopper, and conveyed to the outside of the housing 15 by the scraper conveyor 22.

Problems to be Solved by the Invention As can be understood from the above-described configuration of the electrostatic brush cleaning device, the cleaning device electrostatically collects toner from the conductive brush 17 in the toner recovery roll.
Since the toner is conveyed to 19, the toner is easily separated from the conductive brush 17, and the separated toner adheres to the inner wall of the cleaner device.
As a result, the toner drops onto the photoconductor 1, and the toner further enters and accumulates in the conductive brush 17, and the toner drops onto the photoconductor 1 to stain the photoconductor 1 and cause a copy image. It was a trouble that had an adverse effect.

Conventionally, in order to prevent this trouble, the housing is forced
For example, a method of collecting the toner by sucking the air of 15 or by artificially providing a protrusion inside the housing 15 and making an air flow by using the rotation of the conductive brush 17 is used. It was

However, in order to forcibly perform air suction, a suction device is required, and there are problems of space, cost, and noise. Further, in the air flow created by using the rotation of the conductive brush 17 by providing the protrusion, there is a limit to the suction force no matter how high the rotation speed of the brush 17 is increased, and it is difficult to reduce the degree of dirt. It was

Means and Actions for Solving the Problems The present invention has been conceived in view of the above, and the toner accumulated on the inner wall of the cleaning device or the toner accumulated in the conductive brush without any other auxiliary means. It is intended to provide an electrostatic brush cleaning device capable of reducing the amount of toner, preventing toner from falling onto the photoconductor, and eliminating adverse effects on copy images.
The structure is the same as in the electrostatic brush cleaning device of the electrophotographic copying machine for cleaning the surface of the photoconductor 1 by rubbing the conductive brush 17 on the surface of the photoconductor 1.
17 is provided inside the housing 15 which is disposed above the photoconductor 1 and whose lower side is opened, and a toner recovery roll 19 is provided so as to contact the conductive brush 17, and the conductive brush 17 is provided.
A bias voltage of the same polarity is applied to the toner recovery roll 19 so that the voltage value applied to the toner recovery roll 19 is higher than the voltage value applied to the conductive brush 17, The rotation speed of the tip of the conductive fiber is 40 to 200 mm / s, and the residual toner is removed by the conductive brush 17 that rotates while rubbing against the surface of the photoconductor 1. The toner adsorbed on the conductive brush 17 is transferred to the toner recovery roll 19 and then scraped off by the scraper 21.

EXAMPLE An example of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 2 shows a schematic overall structure of an electrophotographic copying machine in which the present invention can be suitably implemented. In this figure, 1 is an endless winding wound around a tension roll 2, a peeling roll 3 and a driving roll 4. It is a belt-shaped photosensitive member (image bearing member) that is rotated in the direction of the arrow by the drive roll 4.

In the vicinity of the photoconductor 1, reflected light from the charger 5 for charging the photoconductor 1 and the original 7 to be copied placed on the original table 6 is imaged to form an image of the photosensitive body 1. An optical system 8 for forming an electrostatic latent image on the surface, a developing device 9 for developing the electrostatic latent image formed on the surface of the photoconductor 1 into a visible image (toner image),
A transfer device 12 for transferring the visible image on the surface of the photoconductor 1 onto the paper 11 fed from the paper feeding device 10, a fixing device 30 for permanently fixing the toner transferred onto the paper 11 after the transfer step, A sheet 32 that guides the paper 11 that progresses after fixing to the catch tray 31, a preclean lamp 13 'that uniformly discharges the surface of the photoconductor 1, and a preclean corotron 13 that charges untransferred toner to a uniform polarity. An electrostatic brush cleaning device 14 that removes untransferred toner remaining on the surface of the photoconductor 1 after the pretreatment process for cleaning is installed in the above order along the rotation direction of the photoconductor 1.

On the other hand, the electrostatic brush cleaning device 14 has two housings 15 and 16 as shown in FIG. One of the housings 15 of the housings 15 and 16 is a photosensitive member 1.
Is installed above the photoconductor 1 so as to be close to the photoconductor 1, and the surface facing the photoconductor 1 is opened, that is, the lower side is open, and the inside is electrically conductive so that the tip slides on the surface of the photoconductor 1. A sex brush 17 is housed. The conductive brush 17 has a large number of conductive fibers 17b laid on the surface of a cylindrical core 17a. The conductive brush 17 is rotated in the direction of the arrow by a drive system (not shown) to remove untransferred toner remaining on the surface of the photoconductor 1. It is supposed to be removed.

The material of the bristle of the conductive brush 17 is REC (trade name: Unitika) in which carbon is dispersed in rayon, SA-7 (Toray) in which carbon is contained in acrylic, or Bertlon (made by Kanebo). The conductive fibers containing carbon whose resistance value is easily changed and the conductive fibers containing metals such as copper and nickel are used.

A bias voltage of, for example, +200 V is applied to the conductive brush 17 and the housing 15 from a DC bias power source 18. In addition, an opening portion 15a that opens into the housing 16 is provided at the top of the housing 15 and the opening portion 15a
Toner collection roll in contact with the conductive brush 17
19 are provided. The toner recovery roll 19 is rotated in the direction of the arrow by a drive system (not shown), and a bias voltage of + 500V, for example, is applied by the toner recovery bias power source 20 in the same manner as the conductive brush 17, and The toner adsorbed to the conductive brush 17 from the surface is further adsorbed and removed from the conductive brush 17.

The toner adsorbed on the toner collecting roll 19 is scraped off by a scraper 21 made of metal such as a stainless plate provided so as to be in contact with the toner collecting roll 19, and then is transferred to the housing 16 by a conveying means 22 such as a screw conveyor. As well as being carried out from the inside,
The housing 16 is grounded to one side of the DC bias power supply 18.

The electrostatic brush cleaning device 14 configured as described above removes the untransferred toner remaining on the surface of the photoconductor 1 after the toner image is transferred onto the paper 11 by the normal copying process as follows. To do.

That is, the untransferred toner remaining on the surface of the photoreceptor 1 after the transfer step is uniformly charged by the preclean corotron 13, and at the same time, the photoreceptor is illuminated by the preclean lamp 13 'from the transparent support side of the photoreceptor 1. After the binding force with the surface of No. 1 is weakened, it reaches the conductive brush 17 provided in the brush cleaning device 14. A bias voltage having a polarity opposite to that of the toner is applied to the conductive brush 17 by the DC bias power source 18, and the residual toner is removed from the surface of the photoconductor 1 by the conductive brush 17 which rotates while slidingly contacting the surface of the photoconductor 1. To be done.

At this time, set the brush speed of the conductive brush 17 to 40 to 20.
By setting it to 0 mm / s, it becomes possible to reduce the amount of toner in the brush 17 and the amount of toner attached to and deposited on the inner wall of the housing 15 of the cleaning device body 14 to 1/2 to 1/3.

Further, the toner adsorbed on the conductive brush 17 is transferred to the toner collecting roll 19, then scraped off from the surface of the toner collecting roll 19 by the scraper 21, and further carried out by the carrying means 22 from the inside of the housing 16 and collected.

It should be noted that, in the above-described embodiment, even if the speed of the toner recovery roll 19 is increased, it is considered that the toner recovery rate from the conductive brush 17 is increased and the same effect can be obtained. However, the speed of the toner recovery roll 19 is increased, for example, 1000 mm / s
Surface of the toner recovery roll 19 and the scraper 21
Abrasion of the toner collection roll 19 and the scraper
The life of 21 will be shortened. As for the cleaning property, if the brush speed is greater than 40 mm / s, it will not adversely affect the next process.

FIG. 3 shows the relationship between the brush speed of the conductive brush 17, that is, the rotation speed at the tip of the fiber of the brush 17 and the cleaning capacity (output toner concentration). The brush speed may be 40 mm / s or more. I understand. If this is less than 40 mm / s, the cleaning effect cannot be obtained.

On the other hand, FIG. 4 shows the relationship between the amount of toner adhering to the inner wall of the housing 15 of the cleaning device 14 and the brush speed. If the brush speed is about 200 mm / s or less, it is within the allowable range, and if it is more than that, the inner wall is shown. Toner amount has increased.

FIG. 5 shows the relationship between the toner amount in the brush of the conductive brush 17 and the brush speed. When the brush speed was 200 mm / s or less, the toner amount in the brush was at an allowable level.

Regarding each of the above brush speeds, conventionally, as shown in each figure, a brush speed of considerably higher than 200 mm / s is used, and in the present invention, the brush speed does not exceed 200 mm.

In the above embodiment, the endless belt-shaped one is used as the photoconductor 1, but the photoconductor 1 may be a roll-shaped one used in a general electrophotographic copying machine.

EFFECTS OF THE INVENTION According to the present invention, toner is electrostatically collected by the toner collecting roll to prevent the generation of a toner cloud, and the adhesion of the toner to the inner wall of the cleaning device or the toner is performed without other auxiliary means. It is possible to reduce the amount of toner accumulated in the conductive brush to which a predetermined bias voltage for transporting the toner to the collecting roll is applied. The adverse effect can be eliminated. As an additional effect, by slowing the brush speed, the mechanical load on the photoconductor 1 is reduced and the life of the photoconductor 1 can be extended.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic structure of an electrostatic brush cleaning device, FIG. 2 is a schematic structure explanatory view of an electrophotographic copying machine, and FIG. 3 is a diagram showing a relationship of cleaning ability with respect to brush speed. FIG. 4 is a diagram showing the relationship between the brush speed and the toner amount on the inner wall of the cleaning device, and FIG. 5 is a diagram showing the relationship between the brush speed and the toner amount in the conductive brush. 17 is a conductive brush.

Front page continuation (72) Inventor Kazuhiro Iwaoka 2274 Hongo, Ebina City Fuji Zerox Co., Ltd. at Ebina Works (56) References JP 58-76871 (JP, A) JP 58-62680 (JP, A) JP-A-57-66464 (JP, A) JP-A-62-187377 (JP, A) JP-A-60-181774 (JP, A) JP-A-60-101576 (JP, A) JP-A-60-101575 (JP, A) JP 58-111077 (JP, A) JP 60-97380 (JP, A) JP 55-127587 (JP, A) Actual development JP 59-168767 (JP, U)

Claims (1)

(57) [Claims] 1. An electrostatic brush cleaning device for an electrophotographic copying machine, wherein an electroconductive brush 17 is rubbed against the surface of a photoconductor to clean the surface of the photoconductor.
17 is provided inside the housing 15 which is disposed above the photoconductor 1 and whose lower side is opened, and a toner recovery roll 19 is provided so as to contact the conductive brush 17, and the conductive brush 17 is provided.
A bias voltage of the same polarity is applied to the toner recovery roll 19 so that the voltage value applied to the toner recovery roll 19 is higher than the voltage value applied to the conductive brush 17, The electrostatic brush cleaning device is characterized in that the rotation speed at the tip of the conductive fiber is 40 to 200 mm / s.