JPH07295352A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate need for specially providing an image forming device with an electrostatic charger, a discharge toner recovery box and the like, to miniaturize the whole of the device and to reduce the manufacturing cost thereof. CONSTITUTION:When a photoreceptive drum 12 is rotated in a direction shown by the arrow, the surface thereof is electrostatically charged to have positive polarity by a bias voltage impressed on a cleaning blade 30 and toner 24 is triboelectrically charged to have negative polarity by an elastic blade 26. Besides, a toner thin layer 42 is formed on the surface of the drum 12 by the blade 26. The toner 24 left on the surface of the drum 12 after an exposure process and a transfer process are finished is carried to the toner box 22 of a developing device 14 and scraped by the blade 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus,
In particular, the present invention relates to an image forming apparatus applied to a printer, a copying machine, a facsimile, or the like.

[0002]

2. Description of the Related Art A conventional image forming apparatus 1 shown in FIG. 5 includes a photosensitive drum 2 which is rotated by a motor (not shown). A discharge lamp 3, a charger 4, and an exposure lamp are provided around the photosensitive drum 2. 5, toner box 6a and developing roller 6
A developing device 6, a transfer device 7, a cleaning device 8 and the like having the same b are sequentially provided. When the surface of the photoconductor drum 2 uniformly charged by the charger 4 is irradiated with the light image from the exposure lamp 5, an electrostatic latent image is formed on the surface of the photoconductor drum 2 according to its photoconductive property. To be done. The electrostatic latent image is developed with toner by the developing device 6. And
The toner image formed on the surface of the photoconductor drum 2 is transferred by the transfer device 7 to the recording material 9 conveyed between the photoconductor drum 2 and the transfer device 7. The toner and charges remaining on the surface of the photoconductor drum 2 after the transfer is removed by the cleaning device 8 and the charge eliminating lamp 3.

[0003]

In the prior art, many components such as the static elimination lamp 3, the charging device 4, the exposure lamp 5, the developing device 6, the transfer device 7 and the cleaning device 8 were required. There is a problem that the whole is large and the manufacturing cost is high. Therefore, a main object of the present invention is to provide an image forming apparatus capable of downsizing the entire apparatus and reducing the manufacturing cost.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a photosensitive member, a developer container in which a developer is stored, a developer is triboelectrically charged, and a thin layer of the developer is formed on the surface of the photosensitive member. Means, exposure means for exposing the surface of the photoconductor to form an electrostatic latent image, transfer means for transferring the developer on the electrostatic latent image to a recording material, and cleaning provided in association with the developer accommodating container An image forming apparatus including a device, wherein the cleaning device has a cleaning blade for scraping off the developer remaining on the surface of the photoreceptor, and the developer scraped off by the cleaning blade is directly collected in the developer container. And an image forming apparatus.

[0005]

A cleaning device is provided in association with the developer accommodating container so that the developer remaining on the surface of the photoconductor is directly recovered in the developer accommodating container, so that the scraped developer is recovered. There is no need to provide a separate container. If a bias voltage is applied to one or both electrodes of the cleaning device and the thin layer forming means to charge the photoconductor, it is not necessary to separately provide a charger.

[0006]

According to the present invention, since the number of parts can be reduced, the entire apparatus can be downsized and the manufacturing cost can be reduced. The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.

[0007]

EXAMPLE An image forming apparatus 10 of this example shown in FIG.
Is applied to a printer, a copying machine, a facsimile, or the like, and includes the photosensitive drum 12. The photosensitive drum 12 includes a transparent cylinder 12a, and a transparent conductive layer 12b and a photoconductive layer 12c are provided on the outer peripheral surface of the transparent cylinder 12a.
Are formed in this order. The photosensitive drum 12 is rotated in the arrow direction by a motor (not shown). A developing device 14 and a transfer device 16 are arranged around the photosensitive drum 12 in this order from the upstream side in the rotation direction of the photosensitive drum 12, and an exposure device 18 is arranged inside the photosensitive drum 12. It

The developing device 14 includes a toner box 22 having an opening 20 in the lower part thereof, and a developer 24 such as an insulating toner (hereinafter simply referred to as "toner") 24 is accommodated in the toner box 22. . At the downstream side of the opening edge of the toner box 22 in the rotation direction of the photoconductor drum 12, the abdomen near the free end of the photoconductor drum 1 is provided.
Elastic blade 2 so as to contact the surface of 2 with a predetermined pressure.
6 is attached.

Further, inside the toner box 22, a cleaning device 28 for directly collecting the residual toner 24 in the toner box 22 is provided. The cleaning device 28 includes a cleaning blade 30 which is made of a conductive material such as conductive urethane rubber and is brought into contact with the surface of the photosensitive drum 12 at a predetermined pressure. The cleaning blade 30 is provided with a support member 32 for supporting the cleaning blade 30, and a bias power source 34 is connected to the cleaning blade 30. In addition to the DC bias voltage, a bias voltage obtained by superimposing AC on DC may be applied to the cleaning blade 30.

The transfer device 16 includes a transfer roller 36,
A bias power source 38 is connected to the transfer roller 36.
However, as the transfer device 16, a device using a corona discharger whose transfer voltage is controlled by a grid electrode may be used. The exposure device 18 includes an LED head array 40.
And the like, the light image from the LED head array 40 is applied to the photoconductive layer 12c of the photoconductor drum 12. An exposure point A is a point on which the light image is irradiated.

In operation, when the photosensitive drum 12 is rotated in the direction of the arrow by a motor (not shown), the surface of the photosensitive drum 12 is positively charged by the electric field effect of the bias voltage applied to the cleaning blade 30. In addition, the toner 24 supplied to the photosensitive drum 12 through the opening 20 of the toner box 22 causes the elastic blade 2 to move.
6 is negatively charged by friction. The charging polarity of the toner 24 is determined by the materials of the toner 24 and the elastic blade 26.

In this way, the surface of the photosensitive drum 12 is uniformly charged to the positive polarity, and at the same time, the photosensitive drum 12 is charged.
A thin toner layer 42 uniformly charged with a negative polarity is formed on the surface of the toner, and the thin toner layer 42 is conveyed to the exposure point A (FIG. 1). When the surface (exposure point A) of the photoconductor drum 12 is exposed by the exposure device 18, only the surface potential V _L of the exposed portion becomes low potential, and as shown in FIG. 2, the well type potential of the electrostatic latent image is changed. It is formed.

In the transfer step, the toner 24 on the electrostatic latent image is transferred onto the recording paper 44 supplied from the paper feeding means (not shown). The bias voltage V _T applied from the bias power source 38 to the transfer roller 36 is | V _S |> | V when the potential of the non-exposed portion of the photosensitive drum 12 is V _S and the potential of the exposed portion is V _L. It is set to satisfy _T |> | _VL | (Fig. 2). Therefore, as shown in FIG. 2, the toner 24 in the non-exposed portion is subjected to the Coulomb force F _D toward the photosensitive drum 12, and the toner 24 in the exposed portion is subjected to the Coulomb force F _P toward the recording paper 44 side. , Only the toner 24 in the exposed portion is selectively transferred to the recording paper 44. The recording paper 44 to which the image is transferred is discharged to the outside after the image is fixed through a fixing device (not shown).

After completion of the transfer process, the photosensitive drum 1
The toner 24 remaining on the surface of No. 2 is conveyed into the toner box 22 of the developing device 14, and the cleaning blade 3
It is scraped off by 0. According to this embodiment, since the cleaning device 28 is provided in the toner box 22 and the bias voltage is applied to the cleaning blade 30 to charge the photosensitive drum 12, the charging device, the waste toner collecting container, and the like are installed. There is no need to provide it separately. Therefore, the exposure apparatus 18 is provided inside the photoconductor drum 12, and the entire apparatus can be downsized, and the manufacturing cost can be reduced.

Although a bias voltage is applied to the conductive cleaning blade 30 in this embodiment, the supporting member 32 for supporting the cleaning blade 30 is made of a conductive material and is attached to the supporting member 32. A bias voltage may be applied. In this case, the cleaning blade 30 may be made of an insulating material.

Further, the cleaning blade 30 is provided at an arbitrary position between the inlet 46 of the toner box 22 and the elastic blade 26 so that the scraped toner 24 can be directly collected in the toner box 22. For example, as shown in FIG. 3, the toner box 22
It may be attached to the upstream side portion in the rotation direction of the photoconductor drum 12 at the opening edge.

Further, in the above embodiment, the photosensitive drum 1
2 is positively charged and the toner 24 is negatively charged. On the contrary, the photosensitive drum 12 is negatively charged and the toner 24 is positively charged. You may However, even in this case, the transfer bias voltage V _T is | V _S |> | V _T |> | V _L |
Must be set to satisfy (Fig. 3).

Then, the toner 24 in the non-exposed area is transferred to the transfer material 4
4, the charge polarity of the photoconductor drum 12 and the charge polarity of the toner 24 become the same, so that the elastic blade 26 contacts at least the photoconductor drum 12 as shown in FIG. 4, for example. A part or the vicinity thereof may be formed of a conductive material, and a bias power supply 46 may be connected to the part to apply a bias voltage. In this case, the charging potential of the photosensitive drum 12 can be further stabilized by the bias voltage applied from the two bias power sources 34 and 48.

Further, in this embodiment, the exposure device 18 is arranged inside the photosensitive drum 12, but
The exposure device 18 may be arranged outside the photoconductor drum 12. Further, instead of the photosensitive drum 12, a photosensitive belt or the like may be used.

[Brief description of drawings]

FIG. 1 is an illustrative view showing one embodiment of the present invention.

FIG. 2 is an illustrative view showing a well type potential of an electrostatic latent image in an exposed portion.

FIG. 3 is an illustrative view showing another embodiment of the present invention.

FIG. 4 is an illustrative view showing a state in which a bias power source is connected to the elastic blade in the embodiment of FIG.

FIG. 5 is an illustrative view showing a conventional technique.

[Explanation of symbols]

 10 ... Image forming device 12 ... Photosensitive drum 14 ... Developing device 16 ... Transfer device 18 ... Exposure device 22 ... Toner box 24 ... Toner 26 ... Elastic blade 28 ... Cleaning device 30 ... Cleaning blade 32 ... Support members 34, 38 ... Bias Power supply 36 ... Transfer roller

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G03G 15/08 504 A 507 B 15/24 21/10 G03G 21/00 326

Claims (4)

[Claims] 1. A photoreceptor, a developer accommodating container accommodating a developer, a thin layer forming means for frictionally charging the developer and forming a thin layer of the developer on the surface of the photoreceptor, and the photoreceptor. Exposure means for exposing the surface of to form an electrostatic latent image,
An image forming apparatus comprising: a transfer device that transfers the developer on the electrostatic latent image to a recording material; and a cleaning device provided in association with the developer accommodating container, wherein the cleaning device is the photoconductor. An image forming apparatus having a cleaning blade for scraping off the developer remaining on the surface thereof, and directly collecting the developer scraped off by the cleaning blade into the developer accommodating container. 2. The photosensitive member is displaced toward the thin layer forming means through the inside of the developer accommodating container, and from the inlet portion of the developer accommodating container for receiving the photosensitive member to the thin layer forming means. The image forming apparatus according to claim 1, wherein the cleaning blade is provided in the. 3. The cleaning device according to claim 1, wherein the cleaning device has a first electrode to which a first bias voltage is applied, and the photoconductor is charged by the first bias voltage. Image forming apparatus. 4. The thin layer forming means has a second electrode to which a second bias voltage is applied, and the photoconductor is charged by the second bias voltage.
4. The image forming apparatus according to any one of 3 to 3.