JPH0882977A - Electrophotographic recorder - Google Patents

Abstract

PURPOSE: To prevent dust from sticking concentratedly on one spot by reciprocating a charge bruch in a direction parallel with the center axis of a photoreceptor. CONSTITUTION: A charging brush 1 is held by a holder 10 so that it may be parallel with the center shaft of the photoreceptor drum 2. Brush guide members 9 functioning as a rail for allowing the charging brush 1 to reciprocate are fixed at both ends of the drum 2. The brush guide member 9 is a cylindrical member whose inside diameter is larger than the external size of the drum 2, and a groove 91 whose depth is consecutively changed in a wavy state, is formed along the inner peripheral surface of the drum. Both end parts of the brush 1 are put into the groove 91 between the outer periphery of the drum 2 and the guide member 9. When the drum 2 is rotated, both ends of the brush 1 reciprocate in the direction parallel with the center shaft of the drum while coming into contact with the bottom of the groove 91.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic recording device such as a printer or a facsimile having a charging brush.

[0002]

2. Description of the Related Art Generally, in an electrophotographic recording apparatus using a brush charging system, first, an electric charge is applied to a charging brush so that the surface of the photosensitive member is uniformly charged by contacting the surface of the photosensitive member and exposed by a light beam emitted from a laser unit. By doing so, an electrostatic latent image is formed on the surface of the photoconductor. Printing is completed by applying developing toner to the latent image to form an image, transferring the toner image from the surface of the photoconductor to recording paper, and fixing the toner image on the recording paper by a fixing device.

However, not all the toner is transferred from the surface of the photoconductor to the recording paper, and a part of the toner remains on the surface of the photoconductor. As a method for removing this residual toner, there is a method in which the tip of a blade made of rubber, synthetic resin, or the like is pressed against the surface of the photoconductor to scrape off the toner as the photoconductor rotates. Since dust such as toner and paper dust coming out from the recording paper is accumulated and accumulated on the blade tip, the pressure contact state of the blade tip with respect to the photoconductor surface partially becomes defective, and the cleaning function by the blade becomes extremely large. As a result, the dust remaining on the surface of the photoconductor adheres to the charging brush.

[0004]

Most of the conventional charging brushes are fixed, and when dust adheres,
Dust is concentrated on one portion of the brush, and that portion becomes defectively charged, which adversely affects printing.

An object of the present invention is to provide an electrophotographic recording apparatus having a charging brush which prevents dust from concentrating on one place.

[0006]

The electrophotographic recording apparatus of the present invention reciprocates a charging brush in a direction parallel to the center axis of the photoconductor. This makes it difficult for dust to adhere, and even if it adheres, since the charging brush is constantly moving, dust is not collected in one place, so that the amount of partial adhesion can be minimized.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view of an electrophotographic recording apparatus according to an embodiment of the present invention. In the figure, the tips of the bristles 1a of the charging brush 1 come into contact with the surface of the photoconductor drum 2 to uniformly charge the drum surface. The laser unit 3 generates laser light having intensity depending on the image signal, and irradiates the charged surface of the photosensitive drum 2 with the laser light. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 2.

The developing device 4 stores toner therein, and the developing roller 4a causes the toner to adhere to the surface of the photosensitive drum 2 according to the electrostatic latent image to form a toner image. On the other hand, the recording paper 6 is fed from the hopper 20, and the toner image is transferred to the recording paper 6 by the transfer device 5. After the transfer, the fixing device 7 fixes the toner image on the recording paper and finishes the printing.

Since residual toner remains on the surface of the photosensitive drum 2 even after the transfer, it is removed by the cleaning blade 8 and stored in the holder 10.

The feature of this embodiment is that when the charging brush 1 charges the surface of the photosensitive drum 2, it reciprocates in a direction parallel to the drum central axis while contacting the surface of the photosensitive drum 1. . Due to this reciprocating movement, dust on the surface of the photoconductor drum is prevented from concentrating on one location of the charging brush 1, and the drum surface can be uniformly charged. The means for reciprocating the charging brush 1 in the direction parallel to the drum center axis is the structure of the charging brush 1, the holder 10 and the photosensitive drum 1.

FIG. 2 is a view of the photosensitive drum 2 and the charging brush 1 when viewed from the side of FIG. 1, FIG. 3 is a perspective view of the charging brush 1, and FIG. 4 is a perspective view showing an end portion of the photosensitive drum 2. , And FIG. 5 are perspective views showing the charging brush 1 and the holder 10, both of which are embodiments of claim 2.

As shown in FIG. 2, the charging brush 1 is arranged so that the holder 10 is parallel to the drum center axis of the photosensitive drum 2.
Held in. This holding state is not completely fixed,
The charging brush 1 is in a state of being freely movable in the length direction thereof, that is, in the direction parallel to the drum central axis. Brush guide members 9 serving as rails that generate the above-described reciprocating motion of the charging brush 1 are fixed to both ends of the photosensitive drum 2. The brush guide member 9 is a cylindrical member having an inner diameter larger than the outer diameter of the photosensitive drum 2, and a groove 91 whose depth continuously changes in a wavy shape is formed along the circumferential surface of the drum. Both ends of the charging brush 1 enter a groove 91 between the outer periphery of the photosensitive drum 2 and the brush guide member 9. As shown in FIG. 3, bearings are provided at both ends of the charging brush 1, and the bearings come into contact with the bottom of the groove 91 inside the brush driving member 9. The depth of the bottom of the groove 91 changes in a wave shape, and the number of the waves determines the number of reciprocations of the charging brush 1.

That is, when the photosensitive drum 2 rotates,
Both ends of the charging brush 1 reciprocate in a direction parallel to the drum central axis while contacting the bottom of the groove 91. Assuming that the wave forming the bottom of the groove 91 has four cycles, the charging brush 1 reciprocates four times in the drum central axis direction every one rotation of the photosensitive drum 2.

As shown in FIG. 5, the relationship between the charging brush 1 and the holder 10 is such that the charging brush 1 can be freely moved in the longitudinal direction within the guide 11 of the holder 10. The charging brush 1 freely moves in the length direction on the rail 12 of the guide 11.

As described above, the charging brush 1 according to this embodiment is used.
Although the guide 11 of the holder 10 and the brush guide member 9 are used as the means for reciprocating in the direction parallel to the drum center axis, the present invention is not limited to this. For example,
A mechanism may be provided in which the guide 11 is separated from the holder 10 and the charging brush 1 is fixed to the guide 11 to reciprocate together with the guide 11 in a direction parallel to the drum central axis. In this case, while a drive source for reciprocating motion is required,
In the case of the embodiments of FIGS. 1 to 5 described above, the driving source for the reciprocating motion is the rotational force of the photosensitive drum, so there is an advantage that it is not necessary to separately provide a driving source, which contributes to reduction of power consumption. To do.

[0017]

As described above, according to the present invention, the charging brush is moved in a direction parallel to the drum center axis to prevent the adhesion of dust such as residual toner to be concentrated in one place, thereby preventing the charging failure and the accompanying charge. This has the effect of eliminating the occurrence of printing defects.

[Brief description of drawings]

FIG. 1 is a sectional view showing an electrophotographic recording apparatus according to an embodiment of the present invention.

2 is a front view of a photosensitive drum and a charging brush of the electrophotographic recording apparatus of FIG.

3 is a perspective view of a charging brush used in the electrophotographic recording apparatus of FIG. 1. FIG.

4 is a perspective view showing one end of a photosensitive drum used in the electrophotographic recording apparatus of FIG.

5 is a perspective view showing a holding state of the charging brush shown in FIG. 3 in a holder.

[Explanation of symbols]

 1 Charging Brush 2 Photosensitive Drum 3 Laser Unit 4 Developing Device 5 Transfer Device 6 Recording Paper 7 Fixing Device 8 Cleaning Blade 9 Brush Guide Member

Claims (2)

[Claims] 1. An electrophotographic recording apparatus using a method of uniformly charging the surface of a photosensitive drum by contacting the charging brush with a means for reciprocating the charging brush in a direction parallel to the central axis of the photosensitive drum. An electrophotographic recording apparatus comprising: 2. The reciprocating means is fixed to both ends of the photosensitive drum and a holder for holding the charging brush so that the charging brush can reciprocate, and a position where both ends of the charging brush come into contact with the drum central axis. And a brush guide member that changes into a wavy shape in a parallel direction, and both ends of the charging brush generate the reciprocating motion while being in contact with the brush guide member as the photosensitive drum rotates. The electrophotographic recording apparatus according to claim 1.