JP4259484B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus applied to a facsimile machine, a copying machine, a printer, and the like.

  Usually, in an electrophotographic image forming apparatus, a charger, an exposure device, a developing device, and a transfer roller are arranged in order along the rotational direction of the photosensitive drum on or above the peripheral surface of the photosensitive drum as a photosensitive member. Has been placed. During the printing operation, the outer peripheral surface of the rotating photosensitive drum is uniformly charged by the charger, and an electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum by the exposure device.

  The electrostatic latent image on the photosensitive drum is supplied with toner by a developing unit to form a toner image, and the toner image is transferred onto a sheet by a transfer roller.

  In such an image forming apparatus, after the toner image is transferred onto the paper, the residual toner remaining on the surface of the photosensitive drum is disturbed by the static eliminating brush and uniformly distributed on the surface of the photosensitive drum. Thereafter, the residual toner dispersed is collected from the photosensitive drum to the developing device by electrostatic attraction. Further, the static elimination brush neutralizes the surface of the photosensitive drum by making contact with the surface.

Patent Document 1 discloses a neutralizing brush that includes such a neutralizing brush and prevents the toner dispersion capability of the neutralizing brush from being lowered.
JP-A-11-3020

  Hereinafter, a neutralizing brush that neutralizes the surface of the photosensitive drum and disturbs residual toner will be described with reference to the drawings. In the following description, an arrow written on the photosensitive drum in the drawing indicates the rotation direction of the photosensitive drum.

  In the conventional image forming apparatus, as shown in FIG. 4, the neutralizing brush 12 has a base 21 fixed to a housing 32 of the apparatus main body, and the brush 20 is brought into contact with the photosensitive drum 10. At this time, if the neutralizing brush 12 is not in contact with the photosensitive drum 10 and a part of the neutralizing brush 12 is lifted, the residual toner cannot be sufficiently disturbed and neutralized. For the purpose of preventing such floating, initial setting of the pressing force of the static elimination brush 12 is performed. If an excessive pressing force is applied during the initial setting, the neutralizing brush 12 may damage the surface of the photosensitive drum 10. In addition, although the pressing force is sufficient at the time of initial setting, the pressing force may change due to distortion of the housing 32, a reduction in brush length due to wear, or deformation of the brush. Such a change in pressing force may cause development failure or damage to the photosensitive drum 10.

  In order to solve the above problems, the present invention uses the following means.

An image forming apparatus having an image forming section for recording an image on the paper, the image forming section, the discharging brush which neutralizes the photosensitive member on which an electrostatic latent image is recorded by exposure machine, the surface of the photosensitive member And the static elimination brush is fixed to the resin casing of the apparatus main body of the image forming apparatus via an elastic member, and the elastic member has a substantially cylindrical cross section, It is movable in two axial directions excluding the axial direction of the photoreceptor. The elastic member is a metal, rubber, or synthetic resin product.

According to the image forming apparatus of the present invention, the neutralizing brush for neutralizing the surface of the photosensitive member is fixed to the apparatus main body via the elastic member, so that the brush length is reduced due to distortion or wear of the casing. By doing so, even when the pressing force changes, the pressure that the elastic member bears flexibly is adjusted, so that development failure or damage to the photosensitive drum is not caused. Furthermore, the elastic member has a substantially cylindrical shape. The neutralizing brush attached in this way can flexibly cope with deformation such as distortion of the resin casing. In addition, since the elastic member is not displaced by the pressing force applied in the same direction as the rotation axis direction of the photosensitive drum, the movement and swinging of the static elimination brush are restricted, and the positional deviation with respect to the width direction of the photosensitive drum. There is nothing to do.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the image forming apparatus 1 includes an apparatus main body 2 serving as a casing. A paper feed cassette 3 is provided below the image forming apparatus 1. A flapper 4 on which a sheet of a predetermined size is placed is provided inside the paper feed cassette 3. A pickup roller 5 is disposed above the paper feed cassette 3 mounted on the apparatus body 2. The flapper 4 is urged upward by a spring member 6 so that the uppermost surface of the loaded paper is in contact with the pickup roller 5. In this state, when the pickup roller 5 is rotationally driven, the paper is conveyed to the conveyance path 7 by a frictional force.

Further, a press roller 8 that is a transport roller for transporting paper and a feed roller 9 are provided in a transport path 7 on the downstream side in the paper transport direction of the pickup roller 5 (hereinafter referred to as “downstream”). The press roller 8 and the feed roller 9 convey the sheet downstream in the conveyance path 7. Further, an image forming unit is provided downstream of the press roller 8 and the feed roller 9, and a photosensitive drum 10 as a photosensitive member and a transfer roller 11 are arranged in the image forming unit. Further, along the peripheral surface of the photosensitive drum 10, a static elimination brush 12 for performing static elimination and toner disturbance on the surface of the photosensitive drum 10 after transfer, and charging for uniformly charging the surface of the photosensitive drum 10. The containers 13 are respectively arranged. An exposure head 15 that forms an electrostatic latent image on the surface of the photosensitive drum 10 in accordance with a signal is disposed near the developing unit 14. Further, in the vicinity of the photosensitive drum 10, a developing device 14 is arranged that moves the toner to an electrostatic latent image to make a visible image. The transfer roller 11 is provided at a position facing the photosensitive drum 10 with the conveyance path 7 interposed therebetween, and a toner image formed on the transfer roller 11 is transferred to the surface of the paper.

  Further, a fixing roller 16 and a press roller 17 are disposed in the conveyance path 7 downstream of the photosensitive drum 10, and the toner image transferred onto the sheet is transferred to the surface of the sheet by the fixing roller 16 and the press roller 17. Fixed to.

  Further, a pair of paper discharge rollers 18 is arranged in the conveyance path 7 downstream of the fixing roller 16, and the conveyed paper is discharged to the discharge tray 19 by the pair of paper discharge rollers 18.

  Here, as shown in FIG. 2, the static elimination brush 12 is attached so as to contact the surface of the photosensitive drum 10.

  The neutralizing brush 12 includes a conductive brush 20 that contacts the photosensitive drum 10 and neutralizes the surface thereof, and a base 21 to which the brush 20 is fixed. The neutralizing brush 12 is connected to the device via an elastic member 22. It is attached to the housing 32 of the main body. The elastic member 22 is a rubber or synthetic resin product formed in a sponge shape, and is deformed when the same force is applied as compared with a plate material made of a rubber or synthetic resin product formed in a plate shape. The amount is getting bigger.

  As described above, when the static elimination brush 12 is attached to the housing 32 of the apparatus main body via the elastic member 22, the sponge-like elastic member 22 is pressed and brought into contact with the photosensitive drum with internal stress. ing. By attaching in this way, for example, when the brush 20 is worn out by long-term use and the decrease in the length is reduced, a gap is generated at the contact portion between the brush 20 and the photosensitive drum 10. Since the static elimination brush 12 is pressed toward the photosensitive drum 10 by the internal stress, there is no gap between them. Further, the housing 32 of the apparatus main body molded with resin may be distorted by the internal stress, and the housing 32 may be deformed. Even when the distance between the photosensitive drum 10 and the housing 32 is reduced due to such deformation, the elastic member 22 is flexibly adjusted to adjust the pressing force, which may cause development failure or damage to the photosensitive drum. Absent.

  Next, a second embodiment of the present invention shown in FIG. 3 will be described.

  Here, only the configuration peculiar to this embodiment will be described below, and the same configuration as that of the first embodiment described above is denoted by the same reference numeral, and description thereof is omitted.

  In this embodiment, the neutralizing brush 12 includes a conductive brush 20 that contacts the photosensitive drum 10 and neutralizes the surface thereof, and a base 21 to which the brush 20 is fixed. The neutralizing brush 12 has a cross section. It is attached to the housing 32 of the apparatus main body via a cylindrical elastic member 23 formed in a substantially cylindrical shape. The cylindrical elastic member 23 is a metal, rubber, or synthetic resin product formed in a substantially cylindrical shape, and swings in the vertical and horizontal directions with respect to the paper surface of FIG. However, movement and swinging in the same direction as the axial direction of the photosensitive drum 10 (direction perpendicular to the paper surface of FIG. 3) are restricted.

  In the image forming apparatus of the present embodiment, the pressing force is flexibly adjusted by the elastic deformation of the cylindrical elastic member 23. Further, since the movement and swinging of the photosensitive drum 10 in the same direction as the rotation axis direction are restricted, the static elimination brush 12 is not displaced with respect to the width direction of the photosensitive drum 10. Therefore, development failure or damage to the photosensitive drum 10 is not caused.

  The configuration of the image forming apparatus shown in the present embodiment is merely an example, and it is needless to say that the design can be changed as appropriate without departing from the gist of the present invention.

1 is a diagram illustrating a schematic cross section of an image forming apparatus 1 provided with a charge eliminating brush 12. FIG. It is a figure which shows the static elimination brush 12 and elastic member 22 of 1st embodiment of this invention. It is a figure which shows the static elimination brush 12 and the cylindrical elastic member 23 of 2nd embodiment of this invention. It is a figure which shows the attachment state of the static elimination brush.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Paper feed cassette 10 Photosensitive drum 12 Static elimination brush 20 Brush 21 Base 22 Elastic member

Claims (2)

An image forming apparatus having an image forming unit for recording an image on paper,
The image forming unit includes a photoconductor on which an electrostatic latent image is recorded by an exposure machine, and a static elimination brush that neutralizes the surface of the photoconductor.
The static elimination brush is fixed to the resin casing of the apparatus main body of the image forming apparatus via an elastic member ,
The image forming apparatus , wherein the elastic member has a substantially cylindrical cross section and is movable in two axial directions excluding the axial direction of the photosensitive member . The image forming apparatus according to claim 1, wherein the elastic member is a metal, rubber, or synthetic resin product.

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