JP2002006705A - Image forming device - Google Patents

Abstract

(57) [Problem] To use a small and inexpensive electrophotography method, which is capable of obtaining a clean image excellent in cleaning performance of residual toner on a photoconductor and extending the life of the photoconductor. It is an object of the present invention to provide an image forming apparatus. An image forming apparatus according to the present invention is an image forming apparatus using an electrophotographic method, wherein an electrostatic latent image is formed by an exposure unit and a toner adhered to a roller-shaped or belt-shaped photoconductor is transferred to a transfer material. Cleaning blade 2 that scrapes off toner remaining on the photoreceptor after transfer to
3, and a charge eliminator connected to the cleaning blade 23 for removing charges remaining on the photoconductor.

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 for forming an image using an electrophotographic system.

[0002]

2. Description of the Related Art In recent years, in an image forming apparatus employing an electrophotographic system, an electrophotographic photosensitive member as an image carrier is charged by a charger, and the photosensitive member is irradiated with light according to image information to form a latent image. An image is formed, and the latent image is developed by a developing device, and the visualized toner image is transferred to a sheet material or the like to form an image.

On the other hand, a plurality of image carriers on which such a series of image forming processes are developed in accordance with colorization of an image are provided, and each color image of a cyan image, a magenta image, a yellow image, and preferably a black image is provided. Is formed on each image carrier, and a full-color image is formed by superimposing and transferring each color image on a sheet material at a transfer position of each image carrier. This tandem-type image forming apparatus is said to be advantageous for speeding up since it has an image forming unit for each color, and many proposals have been made.

Hereinafter, a conventional tandem type color image forming apparatus will be described with reference to the drawings.

FIG. 3 is a structural view of a conventional image forming apparatus, and FIG. 4 is a sectional view of a main part of a conventional image forming unit.

In FIG. 3, reference numeral 1 denotes an image forming apparatus main body for forming a full-color image on paper using a laser, and 2 denotes an image signal to output yellow (Y), magenta (M),
The exposure unit irradiates light according to an image signal to the image forming units 3, 4, 5, and 6 for forming toner images of cyan (C) and black (K), respectively. Arrows shown from the exposure device 2 toward the image forming units 3, 4, 5, and 6 indicate light emitted from the exposure device 2 in accordance with an image signal. In the yellow image forming unit 3, reference numeral 3 a denotes a photosensitive drum having an optical semiconductor layer formed on a surface on which an electrostatic latent image is formed by light irradiated by the exposure device 2, and 3 b is in close contact with the photosensitive drum 3 a and is exposed to light. Body drum 3
The charging roller 3c is a developing roller that adheres tightly to the photosensitive drum 3a and attaches a toner image to the electrostatic latent image formed on the photosensitive drum 3a. Silicon rubber having a conductivity of about 10 ⁴ to 10 ⁶ Ω · cm is formed in a roll shape. Reference numeral 3d denotes a cleaner for cleaning by scraping off the toner image remaining on the photosensitive drum 3a after the transfer. Photoconductor drum 3
a, charging roller 3b, developing roller 3c, cleaner 3d
Are provided in the magenta, cyan, and black image forming units 4, 5, and 6, respectively. 7 is an image forming unit 3, 4,
An intermediate transfer belt formed between the transfer rollers 5 and 6 and the transfer roller 12 so as to run in a closed loop, and 8 is an intermediate transfer belt in which a toner image attached to an electrostatic latent image on the photosensitive drum 3a is in close contact with the photosensitive drum 3a. A transfer device for positively charging the intermediate transfer belt for transferring the image to the paper 7; a paper cassette 9 for storing the paper P; a pickup roller 10 for taking out the paper P one by one from the paper cassette 8; It is a paper feed roller that transports the taken out paper P. Reference numeral 12 denotes a transfer roller which is in close contact with the intermediate transfer belt 7, and a sheet P conveyed by the sheet feed roller 11.
Is transported between the intermediate transfer belt 7 and the transfer roller 12. 13 is a fixing device having a roller provided with a heating device,
Reference numeral 14 denotes a paper discharge roller for discharging the paper P on which the toner image has been formed to the storage tray 15.

In FIG. 4, reference numeral 16 denotes a toner obtained by coating a magnetic material powder with a yellow synthetic resin and solidifies it;
A developer container 18 for housing the toner container 6 is a toner stirring member made of a synthetic resin rotatably supported at both ends by the developer container 17 to prevent aggregation of the toner 16 and to convey the toner 16. Reference numeral 19 denotes a toner replenishing roller for replenishing the toner 16 conveyed by the toner agitating member 18 to the developing roller 3c, and the metal core has a volume resistivity of 10 ⁷ Ω · cm.
A urethane foam sponge having a degree of conductivity is bonded in a roll shape. Both ends of the toner supply roller 19 and the developing roller 3c are held by the developing container 17 so as to be rotatable in the arrow direction. Reference numeral 20 denotes a doctor blade provided with urethane rubber at one end of a leaf spring material such as stainless steel or phosphor bronze to be in contact with the developing roller 3c.
The thickness of the toner 16 attached on the surface c is made uniform and a charge is applied to the toner 16. Reference numeral 21 denotes a cleaning blade provided at one end with an elastic body such as a urethane sheet which abuts over the entire width of the photosensitive drum 3a;
A static eliminator for exposing and removing the residual electrostatic latent image remaining on the photosensitive drum 3a.

First, the operation of the image forming apparatus configured as described above will be described.

The surface of the yellow photosensitive drum 3a is uniformly negatively charged by a charging roller 3b connected to a high voltage power supply. Thereafter, based on the image information transmitted from the host computer (not shown) to the exposure device 2, the exposure device 2 irradiates the photosensitive drum 3a with laser light,
In the irradiated portion, negative charges disappear due to the action of the optical semiconductor formed on the surface of the photosensitive drum 3a, and an electrostatic latent image of a yellow component color is formed. When the negatively charged yellow toner is brought close to the photosensitive drum 3a on which the electrostatic latent image is formed by using the developing roller 3c, the electrostatic latent image portion (the portion where the electric charge is lost) on the photosensitive drum 3a 3), the yellow toner adheres to only (1), and is visualized as a yellow toner image. Since the portion other than the electrostatic latent image on the photosensitive drum 3a is negatively charged, the negatively charged toner does not repel and adhere. A positive transfer voltage is applied to the transfer device 8 from the inner surface of the intermediate transfer belt 7 which is in contact with the photosensitive drum 3a and runs in the direction of arrow A, with respect to the yellow toner image thus visualized. Thereby, the image is transferred onto the intermediate transfer belt 7.

In the same manner, a magenta component latent image is formed in the magenta image forming unit 4, and a magenta toner image by magenta toner is visualized. This magenta toner image is transferred to the intermediate transfer belt 7 on which the transfer of the yellow toner image has been completed, so as to overlap the yellow toner image. The yellow toner remaining on the photosensitive drum 3a when transferred to the intermediate transfer belt 7 is removed from the yellow toner image on the photosensitive drum 3a.
d, the photosensitive drum 3a prepares for formation of a new electrostatic latent image, and one cycle of yellow image formation ends. Thereafter, image formation is performed in the same manner for the cyan toner image and the black toner image, and the superposition of the four color toner images on the intermediate transfer belt 7 is completed.

The four color toner images formed on the intermediate transfer belt 7 are transferred from a paper cassette 9 to a pickup roller 10,
After being transferred by the transfer roller 12 onto the paper P conveyed by the paper feed roller 11, the toner is fixed on the paper P by passing through a fixing device 13 having a heating roller, and the paper P is discharged from a paper discharge roller. The sheet is guided in the direction of arrow B by 14 and is discharged to the storage tray 15.

Next, the operation of the image forming unit in the image forming apparatus will be described in some detail.

The toner 16 stirred by the toner stirring member 18 is conveyed to the surface of a toner supply roller 19.
The transported toner 16 is transported by a sponge toner supply roller 19 to a nip portion with the developing roller 3c. The toner 16 carried to the nip portion is the developing roller 3c.
And the toner replenishing roller 19 is slid to be negatively charged by frictional force, and electrostatically adheres to the surface of the developing roller 3c.
The toner 16 adhering to the surface of the developing roller 3c is transported to the doctor blade 20, is uniformly thinned, and is further charged by frictional force to increase the charge amount. The charged toner 16 is transferred and adhered to the photosensitive drum 3a from the developing roller 3c due to a potential difference between the bias applied to the developing roller 3c and the grounded photosensitive drum 3a, and the toner 16 is applied to the surface of the photosensitive drum 3a by the toner 16. A visual image is formed.

Thereafter, the visible image is transferred onto the intermediate transfer belt 7 by the transfer device 8, but the toner remaining on the photosensitive drum 3a without being transferred to the intermediate transfer belt 7 is cleaned to obtain a clear image. It is scraped off by the blade 21. Furthermore, the photosensitive drum 3
The remaining electrostatic latent image on a is exposed and neutralized, and the next image forming process is repeated.

[0015]

However, the above-mentioned conventional image forming apparatus has the following problems.

(1) The toner remaining on the photoreceptor after the toner image on the photoreceptor is transferred to the transfer material is mechanically scraped off by a cleaning blade pressed against the photoreceptor. When the cleaning pressure is increased, the cleaning performance is improved, but there is a problem that the surface layer on the photoconductor is peeled off due to squealing, turning over, and the life of the photoconductor is shortened, and when the pressing force is reduced, toner remains and a clean printed surface cannot be obtained. Was.

(2) There is a need for a place for installing a static eliminator for restoring the residual latent image on the photoreceptor to an initial state, so that the size of the image forming unit and the image forming apparatus becomes large.

(3) It is necessary to provide the static eliminator as a single unit, and there is a problem that a control member and control means are required.

The present invention solves the above-mentioned conventional problems, and can obtain a clean image excellent in the cleaning performance of the residual toner on the photoreceptor, can prolong the life of the photoreceptor, and can further reduce the size of the photoreceptor. It is an object of the present invention to provide an inexpensive electrophotographic image forming apparatus.

[0020]

In order to solve the above-mentioned conventional problems, an image forming apparatus according to the present invention is an image forming apparatus using an electrophotographic system, wherein an electrostatic latent image is formed by an exposing means on a roller or A conductive cleaning blade that scrapes off the toner remaining on the photoconductor after transferring the toner attached to the belt-shaped photoconductor to a transfer material;
A static eliminator connected to the cleaning blade for removing electric charges remaining on the photoconductor.

According to this configuration, it is possible to obtain a clean image excellent in the cleaning performance of the residual toner on the photosensitive member, to extend the life of the photosensitive member, and to use a small and inexpensive electrophotographic method. A forming device can be provided.

[0022]

DETAILED DESCRIPTION OF THE INVENTION An image forming apparatus according to a first aspect of the present invention is an image forming apparatus using an electrophotographic method, wherein an electrostatic latent image is formed by an exposing means, and a roller-shaped or belt-shaped photoreceptor is provided. A conductive cleaning blade for scraping off the toner remaining on the photoreceptor after transferring the toner adhered to the transfer material, and a static eliminator connected to the cleaning blade for removing electric charges remaining on the photoreceptor; , Is provided.

This configuration has the following operation.

(1) By applying a voltage by a static eliminator connected to the cleaning blade, the charge holding force between the photosensitive member and the residual toner can be removed, and the residual toner can be easily scraped off from the photosensitive member. Therefore, the pressing force of the cleaning blade against the photoconductor can be reduced, and the life of the photoconductor can be extended.

(2) Since the space in which the static eliminator is provided becomes unnecessary, the size of the image forming apparatus can be reduced and the manufacturing cost can be reduced.

(3) There is no need to provide a static eliminator as a single unit, and members such as control means for static elimination are not required.

Since the cleaning blade needs to remove the toner adhering to the photoreceptor without damaging the photoreceptor, an elastic synthetic resin or rubber is used.

As the charge removing means, for example, a power supply for generating a voltage is used. The voltage applied to the cleaning blade by the charge removing means is selected from DC, AC, DC, and AC that provide the optimum charge removing effect.

According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the cleaning blade comprises: a conductive elastic member; a conductive support member for supporting the elastic member; And a terminal provided on the support member and connected to the static elimination means.

With this configuration, in addition to the function of claim 1,
It has the following functions.

(1) Since the cleaning blade has an elastic body having conductivity, the residual toner can be removed without damaging the photosensitive body with which the elastic body contacts.

(2) Since the supporting member for supporting the elastic body is provided, when the elastic body is pressed against the photosensitive member, the pressing force can be applied uniformly to the elastic body.

Here, the elastic material is silicone rubber, urethane rubber, ethylene propylene rubber, chloroprene rubber,
Conductivity is achieved by kneading a conductive rubber material such as natural rubber, isoprene rubber, nitrile rubber, styrene butadiene rubber, or butyl rubber with an electronic conductive material such as carbon black, carbon fiber, or graphite, or an ionic conductive material. What is provided is suitably used.

Further, it is preferable that the elastic body and the supporting member are bonded with a conductive adhesive. This is because the contact area between the elastic member and the support member increases, so that the contact resistance between the elastic member and the support member can be reduced, and the volume resistivity of the cleaning blade can be reduced.

According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect, wherein the volume resistivity of the cleaning blade is 1 × 10 ⁴ to 1 × 10 ⁷ Ω · c.
m.

With this configuration, the following operation is obtained in addition to the operation of the first or second aspect.

(1) The charge remaining on the photoconductor can be quickly removed, and the toner remaining on the photoconductor can be quickly removed.

(2) The photosensitive drum is not damaged and the image is not deteriorated.

Here, the volume resistivity of the cleaning blade is 1 × 10 ⁴ to 1 × 10 ⁷ Ω · cm, preferably 1 × 10 ⁴ Ω · cm.
It is assumed to be 10 ⁵ to 1 × 10 ⁶ Ω · cm. If the volume resistivity is higher than 1 × 10 ⁶ Ω · cm, it tends to be impossible to remove the electric charge remaining on the photoreceptor even when a voltage is applied to the cleaning blade, and 1 × 10 ⁵ Ω · c
If it is smaller than m, a leak is likely to occur between the photoconductor drum and the cleaning blade, and damage to the photoconductor drum is increased or an image tends to deteriorate, which is not preferable. Further, if it is larger than 1 × 10 ⁷ Ω · cm or smaller than 1 × 10 ⁴ Ω · cm, the tendency becomes remarkable, and neither is preferable.

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

(Embodiment) FIG. 1 is a perspective view of a cleaning blade according to an embodiment of the present invention, and FIG. 2 is a sectional view of a main part of an image forming unit according to the embodiment of the present invention. In the image forming apparatus according to the embodiment of the present invention, the configuration other than the cleaner provided in the image forming unit is the same as that of the conventional electrophotographic apparatus, and thus the same reference numerals are given and the description is omitted.

In FIG. 1, reference numeral 23 denotes a cleaning blade in the image forming unit according to the embodiment of the present invention; 23a, an elastic body obtained by kneading carbon black with urethane rubber to impart conductivity;
Abuts over the entire width of the Reference numeral 23b denotes a support member made of a rigid sheet metal, and reference numeral 23c denotes a terminal provided on the support member 23b and connected to a power supply as a static eliminator for applying a voltage to the cleaning blade 23.

Here, the elastic body 23a and the support member 23b are adhered by a conductive adhesive. The volume resistivity of the cleaning blade 23 is 1 × 10 ⁴ to 1
× 10 ⁷ Ω · cm. Furthermore, the voltage applied to the cleaning blade by the power supply as the static elimination means is:
A direct current, an alternating current, a direct current, and an alternating current that obtain an optimal static elimination effect are selected.

The operation of the image forming apparatus according to the present embodiment configured as described above will be described below.

When a visible image formed by the toner adhered to the photosensitive drum 3a is transferred onto the intermediate transfer belt 7, about 5% of the visible image toner remains on the photosensitive drum 3a. When a DC, AC, or DC and AC voltage is applied to the cleaning blade 23 by a power supply (not shown) serving as a charge removing unit, the charge remaining on the photosensitive drum 3a contacted with the cleaning blade 23 is canceled. Therefore, the adhesive force between the photosensitive drum 3a and the toner can be reduced. Then, the support member 23
The toner remaining on the photosensitive drum 3a can be easily scraped off by the elastic body 23a of the cleaning blade 23, which is supported by the entire width of the photosensitive drum 3a and is uniformly pressed against the photosensitive drum 3a.

As described above, the image forming apparatus according to the present embodiment has the following functions.

(1) By applying a voltage by means of a static eliminator connected to the cleaning blade, the charge holding force between the photosensitive drum and the residual toner can be removed, and the residual toner can be easily scraped from the photosensitive drum. Since the cleaning blade can be dropped, the pressing force of the cleaning blade against the photoconductor can be reduced, and the life of the photoconductor can be extended.

(2) Since the space in which the static eliminator is provided becomes unnecessary, the size of the image forming apparatus can be reduced and the manufacturing cost can be reduced.

(3) It is not necessary to provide a static eliminator as a single unit, and members such as control means for static elimination are not required.

[0050]

As described above, according to the image forming apparatus of the present invention, the following advantageous effects can be obtained.

According to the first aspect of the present invention, (1) the charge holding force between the photoreceptor and the residual toner can be removed by applying a voltage by the static elimination means connected to the cleaning blade; Since the residual toner can be easily scraped off from the photoconductor, the pressing force of the cleaning blade against the photoconductor can be reduced, and the life of the photoconductor can be extended. An excellent image forming apparatus can be provided.

(2) Since the space in which the static eliminator is provided becomes unnecessary, it is possible to provide a high-value-added image forming apparatus capable of reducing the size and the manufacturing cost.

(3) It is not necessary to provide a static eliminator as a single unit, and members such as control means for static elimination are not required. Therefore, an image forming apparatus with high added value that can be reduced in size and reduced in manufacturing cost is provided. be able to.

According to the invention described in claim 2, according to claim 1
(1) Since the cleaning blade is provided with an elastic body having conductivity, it is possible to remove the residual toner without damaging the photosensitive body contacted by the elastic body. And an image forming apparatus having excellent image quality can be provided.

(2) Since the supporting member for supporting the elastic body is provided, when the elastic body is pressed against the photosensitive member, the pressing force can be applied uniformly to the elastic body, and the toner is removed over the entire width. An image forming apparatus having high performance and excellent image quality can be provided.

According to the invention described in claim 3, according to claim 1
Or in addition to the effects of (2), (1) the charge remaining on the photoreceptor can be quickly removed,
It is possible to provide an image forming apparatus with excellent image quality that can quickly remove toner remaining on the photoconductor.

(2) It is possible to provide an image forming apparatus which does not damage the photosensitive drum and does not deteriorate the image and has excellent durability.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cleaning blade according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the image forming unit according to the embodiment of the invention.

FIG. 3 is a configuration diagram of a conventional image forming apparatus.

FIG. 4 is a sectional view of a main part of a conventional image forming unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Exposure device 3, 4, 5, 6 Image forming unit 3a Photoreceptor drum 3b Charging roller 3c Developing roller 3d Cleaner 7 Intermediate transfer belt 8 Transfer device 9 Paper cassette 10 Pickup roller 11 Paper feed roller 12 Transfer roller 13 Fixing device 14 Discharge roller 15 Storage tray 16 Toner 17 Developing container 18 Toner stirring member 19 Toner supply roller 20 Doctor blade 21 Cleaning blade 22 Static eliminator 23 Cleaning blade 23a Elastic body 23b Support member 23c Terminal P paper

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsuyoshi Homan 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Kazuhiro Seguchi 1006 Odaka Kadoma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. F term (reference) 2H034 BF03 BF04 BF11 2H035 AA14 AA24 AB03 AZ03 2H078 AA13 AA21 AA29 BB01 CC10 DD42 DD65 DD68

Claims (3)

[Claims] An image forming apparatus using an electrophotographic method, wherein an electrostatic latent image is formed by exposure means and toner adhered on a roller-shaped or belt-shaped photoconductor is transferred to a transfer material, and then the photoconductor is transferred to the transfer member. An image forming apparatus comprising: a cleaning blade having a conductive property for scraping off toner remaining thereon; and a charge removing unit connected to the cleaning blade for removing a charge remaining on the photoconductor. . 2. The cleaning blade according to claim 1, further comprising: a conductive elastic member; a conductive support member for supporting the elastic member; and a terminal provided on the support member and connected to the static eliminator. 2. The method according to claim 1, wherein
An image forming apparatus according to claim 1. 3. The image forming apparatus according to claim 1, wherein the volume resistivity of the cleaning blade is 1 × 10 ⁴ to 1 × 10 ⁷ Ω · cm.