JPH07128998A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To simplify the cleaning of the transfer device and to perform the periodical maintenance in a short time by constituting the transfer means with a discharging wire and the shielding case for shielding the both side of the discharging wire and opening above and below. CONSTITUTION:The device is provided with the transfer means 7 for transferring a visual image from the photoreceptor drum 11 to the transfer paper, and the desticization means 8 for eliminating the electric charge of the transfer paper rear side transferred by the transfer means 7. The shielding case 7a of the transfer means 7 and the shielding 8a of the destaticizer 8 are provided with the discharging wire 7b and 8b inside, and the port is formed corresponding to the photoreceptor drum 11, at the same time the port is also formed corresponding to the tray 30. In this way, the shielding case 7a of the transfer means 7 and the shielding case 8a of the destaticization means 8 are constituted so as to be opened in the vertical direction without forming the bottom surface, hence, the toner 13 falls in the tray 30, without staying in the transferring means 7 and the destaticization means 8, and the discharging wire 7b and 8b are not adversely affected, therefore, the clear printing can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus such as a printer or a copying machine using electrophotographic technology.

[0002]

2. Description of the Related Art Generally, in an electrophotographic apparatus, in order to develop an electrostatic latent image, a developer layer, that is, a toner powder is uniformly adhered to a surface of a developing sleeve to form a toner layer. A toner layer is selectively made to adhere to the surface of the photosensitive drum to bring the electrostatic latent image into a visible image by bringing the toner layer into contact with or close to the surface of the photosensitive drum as an image bearing member on which the electrostatic latent image is formed. Is. The thickness of the toner layer is usually about 0.5 to several mm, which is relatively thick. For this reason, the toner particles in the toner layer may separate from the sleeve surface due to the centrifugal force due to the rotation of the developing sleeve, the charging characteristics and magnetic characteristics of the toner, or may not be able to adhere to the drum surface during the transfer to the photosensitive drum surface. As a result, the toner particles fall near the paper guide below the developing device or the transfer device. Then, there is a problem that the dropped particles stain the back surfaces of the paper guide and the transfer paper.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 2-57908, in an electrophotographic apparatus, a conductive member is provided below the developing device so that toner particles scattered from the developing sleeve are electrically connected to the conductive member. Some of them prevent the scattered toner from dropping near the paper guide and the transfer device by being adhered selectively.

However, even if a conductive member is provided as in the above-mentioned known technique, the toner particles are very small and light,
The toner particles on the sleeve surface scatter from the developing roller due to vibration and contact with the photosensitive drum due to the centrifugal force due to the rotation of the developing sleeve, the charging property and the magnetic property of the toner, and the toner does not scatter even if a conductive member is provided. The reality is that it happens.

[0005]

Conventionally, the transfer device as the transfer means is provided below the photosensitive member, and the wire is stretched inside the shield case having only the upper surface opened for facilitating discharge. The scattered toner dropped into the transfer device and was deposited on the bottom surface.

To perform clear printing, the toner adhering to the discharge wire must be removed, but even if the toner adhering to the discharge wire is removed, the toner accumulated on the bottom surface must be removed, and when the toner rises, the discharge There is a problem in that it reattaches to the wire and uniform discharge cannot be performed and clear printing cannot be performed.

Therefore, in order to remove the toner accumulated in the transfer device, the user of the device has performed a complicated work of wiping off the scattered toner with a cotton swab or a cloth soaked with alcohol.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electrophotographic apparatus which simplifies cleaning of a transfer device and enables periodic maintenance in a short time. And

[0009]

The electrophotographic apparatus of the present invention comprises an image carrier, image forming means for forming an electrostatic latent image on the image carrier, and the image carrier formed by the image forming means. A developing means for developing the electrostatic latent image with a powder developer and a transfer means positioned below the developing means and facing the image carrier from below, and discharging the transfer means. It is characterized in that it is configured by a wire and a shield case which is provided along the discharge wire and shields both sides of the discharge wire and opens the upper and lower sides.

[0010]

By forming an opening on the bottom surface of the shield case of the transfer device, it is possible to prevent toner scattered from the developing means from accumulating in the shield case and adhering to the discharge wire, thereby enabling clear printing. it can.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electrophotographic apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of an electrophotographic apparatus. In a housing 2 of a main body 1, a photoconductor unit 3, an exposure unit 4 as image forming means, a developing unit 5 as developing means, and a paper feeding means. A sheet feeding unit 6, a transfer unit 7, a charge eliminating unit 8, a fixing unit 9 and a sheet discharging unit 10 are provided.

The photoconductor unit 3 is provided with a photoconductor drum 11 as an image carrier that rotates in the direction of the arrow, and the surface of the photoconductor drum 11 is provided with the information light 4 from the exposure unit 4.
By exposing with a, an electrostatic latent image is formed on the surface of the photosensitive drum 11. Further, the photoconductor unit 3 includes a charger 12 that uniformly charges the surface of the photoconductor drum 11, a cleaning blade 14a of a drum cleaner 14 that removes toner 13 which is a powder developer remaining on the surface of the photoconductor drum 11, The removed toner 13 that prevents the removed toner 13 from falling onto the charge removal unit 8 and that is deposited on the drum cleaner 14 is sent to the inside of the photoconductor unit 3. A discharge lamp (not shown) for discharging charges remaining on the surfaces of the feed roller 16 and the photosensitive drum 11 is integrally provided.

The exposure unit 4 is, for example, a polygon mirror 1 for scanning a laser beam in the longitudinal direction of the photosensitive drum 11.
7 and an optical system (lens, mirror, etc.) for irradiating the surface of the photosensitive drum 11 with the laser light from the polygon mirror 17.
And 17a.

On the other hand, the developing unit 5 includes the photosensitive drum 1
The electrostatic latent image formed on the surface of No. 1 is developed into a visible image with toner, and as shown in FIG. 1, it has a developing sleeve 18 for adhering the toner 13 to the photosensitive drum 11. The developing unit 5 is provided with a stirring device 19 that stirs the toner 13.

The paper feeding unit 6 is a cassette 20.
A transfer sheet P (not shown), which is a transfer material stored in, is supplied to the transfer means 7, and is composed of a paper feed roller 21 and a transport roller 22. The fixing unit 9 is for fixing a visible image. A transfer material transport path 23 is formed between the cassette 20 and the transfer means 7 through the fixing means 9 by arranging a plurality of guide portions 23a as shown in FIG. A sheet feeding roller 21 and a conveying roller 22 are provided, and a pair of sheet discharging rollers 24 and 25 are provided at both ends of the sheet discharging unit 10 from the rear end of the transfer material conveying path 23 to the upper surface of the housing 2. . The paper discharge unit 10 is for discharging the transfer paper, which has passed through the fixing means 9, from the transfer material discharge port 26 to the outside of the main body 1.

The guide portion 23a is, as shown in FIG.
In order to reduce the resistance to the transfer paper P and to carry the sheet smoothly, a plurality of triangular convex portions 27 are formed at equal intervals, and the concave portions 2 are formed.
8 is formed with a slit 29 serving as a space for guiding the scattered toner, paper dust and dust from the outside of the main body 1 to the bottom of the housing 2.

The transfer means 7 transfers the transfer paper P onto the photosensitive drum 1
1 is transferred, the charge removing unit 8 removes the charges on the back surface of the transfer paper P transferred by the transfer unit 7, and the shield case 7a of the transfer unit 7 and the shield case 8a of the charge removing unit 8 are The discharge wires 7b and 8b are provided inside, and an opening is formed in the photosensitive drum 11 and an opening is also formed in a tray 30 described later. A plate-shaped conductive member 31 is provided between the developing means 5 and the transfer means 7. A bias voltage is applied to the conductive member 31, and the toner 13 scattered from the developing sleeve 18 is electrically attached to the conductive member 31.

From the portion of the developing sleeve 18 to be attached to the photosensitive drum 11, the waste toner 13 is placed in the drum cleaner 14.
To collect the toner 13 scattered in the process of collecting a, or the paper powder and dust from the outside of the main body 1,
The box-shaped tray 3 is provided below the developing unit 5 to the fixing unit 9.
Prepare 0. As shown in FIG. 2, the tray 30 is configured to be detachable from a side surface 32 of the main body 1 by a drawer portion 33 formed in the tray 30.

In such a structure, the photosensitive drum 11
Is charged by the charger 12 in the process of being rotated, and a laser beam is scanned from the exposure unit 4 on the charged portion to form an electrostatic latent image. The electrostatic latent image is developed by the developing unit 5, and the developed image Is transferred by the transfer means 7 to the transfer paper P conveyed from the cassette 20. The transfer paper P on which the image has been transferred is fixed by the fixing means 9, is sent to the paper discharge unit 10, and is transferred from the transfer material discharge port 26 to the housing 2
Is discharged to the upper surface of. In addition, even if transferred, the photosensitive drum 11
The toner 13 attached and left on the cleaning blade 14
It is wiped off by a and accumulated inside the drum cleaner 14.

At this time, the scraped off toner 13 is accumulated by the insulating member 15 so as not to be outside the drum cleaner 14. However, there is a gap between the insulating member 15 and the photosensitive drum 11 such that the toner 13 on the photosensitive drum 11 slips through. This gap is the insulating member 15
This is to prevent the toner 13 on the photosensitive drum 11 from being scraped off. Therefore, the toner 13 scraped off by the cleaning blade 14a may pass through this gap and fall on the transfer unit 7 and the charge eliminating unit 8.

Further, during the rotation of the photosensitive drum 11, the toner 13 may drop from the photosensitive drum 11, and the toner 13 may drop on the transfer means 7 and the charge eliminating means 8.

However, in the electrophotographic apparatus constructed as described above, as shown in FIG. 1, the shield case 7a of the transfer means 7 and the shield case 8a of the static elimination means 8 are open vertically without forming a bottom surface. Therefore, the toner 13 drops into the tray 30, and the toner is not accumulated in the transfer unit 7 and the charge removing unit 8 and the discharge wires 7b and 8 are not collected.
Since there is no adverse effect on b, clear printing can be performed.

Therefore, good transfer and charge removal can be performed simply by cleaning the discharge wire 7b of the transfer unit 7 and the discharge wire 8b of the charge removal unit 8 with a cotton swab or a cloth soaked with alcohol.

Further, as shown in FIG.
By forming the slit 29 in the concave portion 28 of the guide portion 23a which is 3, the scattered toner 13, dust and paper dust from the outside of the main body 1 pass through the slit 29, and the tray 3
It is accumulated at 0.

The toner 13, dust and paper dust accumulated in the tray 30 can be easily cleaned by pulling it out from the side surface 32 of the main body 1 by the pull-out portion 33 of the tray 30 and discarding it.

In the embodiment, the tray is widely provided under the transfer material conveying path, but it goes without saying that the tray may be provided under the transfer means and the charge removing means, respectively.

[0028]

As described above, according to the present invention, since the transfer means is constituted by the shield case in which both sides of the discharge wire are shielded and the upper side is opened, the toner is not accumulated in the transfer means and the transfer process is performed. It is possible to provide an electrophotographic apparatus in which the cleaning can be performed well and cleaning of the transfer unit is easy.

[Brief description of drawings]

FIG. 1 is a schematic view of an electrophotographic apparatus of the present invention.

FIG. 2 is a side view of the electrophotographic apparatus of the present invention.

[Explanation of symbols]

 1 Main Body 2 Housing 4 Exposure Unit (Image Forming Means) 5 Developing Unit (Developing Means) 7 Transfer Means 8 Electrification Means 7a, 8a Shield Case 7b, 8a Discharge Wire 11 Photosensitive Drum (Image Carrier) 13 Toner (Powder Transfer Agent) ) P transfer paper

Claims (1)

[Claims] 1. An image carrier, image forming means for forming an electrostatic latent image on the image carrier, and an electrostatic latent image formed on the image carrier by the image forming means with a powder developer. A developing means for developing using the transfer means, and a transfer means located below the image carrier and facing the image carrier from below, the transfer means being a discharge wire and a discharge provided along the discharge wire. An electrophotographic apparatus comprising a shield case in which both sides of a wire are shielded and upper and lower sides are opened.