JPS62208058A - Recording device preventing developer carrier from floating - Google Patents

Abstract

PURPOSE:To stably hold a photosensitive body and a developer carrier at a constant interval by arranging the intermediate part of an abutting roller below the center of the image carrier. CONSTITUTION:An abutting roller 40 is provided rotatably at both end parts of the shaft 13a of a developing roller 13 and pressed against the photosensitive drum 10 by the pressing member 42 of an attaching/detaching device 41 fitted to a machine frame 39, so that the developing roller 13 is arranged nearby the photosensitive drum 10 in parallel at a constant interval. The center of the abutting roller 40, i.e., the center 01 of the shaft 13a of the developing roller 13 is arranged a little bit below the center 02 of the photosensitive drum 10. The distance l between both centers 01 and 02 is several mm. Consequently, even if a force floating the developing roller 13 operates owing to the driving force of a driving gear, the upward movement of the developing roller 13 is controlled by the abutting rollers 40 which abut the photosensitive drum 10, so the gap between the photosensitive drum 10 and developing roller 13 never becomes unstable.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a recording device such as an electrophotographic copying machine.

[Background of the invention]

2. Description of the Related Art In a recording device, for example, an electrophotographic copying machine, a developing device is disposed on the machine body adjacent to a photosensitive drum. This developing device includes a developing roller, which transports developer to a developing area, and develops an electrostatic latent image formed on a photoreceptor drum to form a toner image. An abutting roller is provided on the shaft of the developing roller, and the abutting roller abuts against the photoreceptor drum, thereby keeping the gap between the photoreceptor drum and the developing roller constant.

[Problem that the invention seeks to solve]

-The center of the photoreceptor drum and the center of the abutting roller that contacts the photoreceptor drum are arranged at the same height. Therefore, when a force that lifts the developing roller is applied due to the driving force of the driving gear of the developing roller, the upward movement of the developing roller is not restricted by the abutment roller, and as a result, the relationship between the developing roller and the photoreceptor drum increases. The gap may become unstable.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a recording apparatus in which the gap between the image carrier and the developer carrier does not become unstable.

[Means for solving problems]

In order to achieve the above object, the present invention has a structure in which a developing device is provided in the vicinity of the image carrier, and a butt is attached to the shaft of the developer carrier. In a recording device in which the abutment roller is in contact with the image carrier to maintain a constant gap between the image carrier and the developer carrier, the center of the abutment roller is set to be lower than the center of the image carrier. It is characterized by being placed in a lower position.

[Effect]

Even if a force to lift the developer carrier acts on the developer carrier due to the driving force of the drive gear of B special holiday, etc.
Since the upward movement is regulated by the abutment roller that is in contact with the image carrier, the developer carrier does not move and the gap between the image carrier and the developer carrier is kept constant.

〔Example〕

FIG. 1 is a schematic sectional view of an electrophotographic copying machine which is an example of a recording device.

Transparent manuscript li at the top edge! The document 2 placed on the table 1 is held down by the document holding cover 3, and when the copy key is pressed, the exposure lamp 5 of the light projecting unit 4 lights up and illuminates the document 2 while moving it along with the reflecting mirror unit 6 in the direction of the arrow. move in the direction. The light irradiated onto the original 2 is transmitted through the reflection mirror 7 of the light projection unit 4, the reflection mirror unit 6, the imaging lens 8, and the reflection mirror 9, as shown by the dotted line.
is guided to the photoreceptor drum lO, which is an image carrier, through
An electrostatic latent image is formed on the photoreceptor drum IO charged by the charging electrode 11. This electrostatic latent image is then developed into a toner image by a developing roller 13, which is a developer carrying member of a developing device 12, which is disposed close to the photosensitive drum IO. After the electric charge on the photoreceptor/drum 10 is removed by the pre-transfer charge removal lamp 14, the toner image is transferred by the transfer 8 to the copy paper 17 conveyed by the conveyance roller 16 from the paper feed cassette 15. be done. The copy paper 17 after transfer is transferred to the photosensitive drum 10 by the separation pole 19.
After being separated from the fixing device 2 by the conveyor belt 20
1, and the toner image is fixed on copy paper 17 by heating roller 22 and pressing roller 23. After the fixing, the copy paper 17 is discharged onto a paper discharge tray 25 by a paper discharge roller 24. On the other hand, copy paper! Photoreceptor drum l from which 7 is separated
O, the residual charge is removed by the removal electrode 2G, the toner remaining on the photoreceptor drum IO is cleaned by the cleaning device f27, the residual charge on the photoreceptor drum IO is removed by the pre-charging charge removal lamp 28, and then the remaining charge is removed from the photoreceptor drum IO by the charge removal lamp 28. Provided for copying.

The developing device 12 will be explained in detail with reference to FIG.

The developing device 12 is located adjacent to the photoreceptor drum 1O in a body 29.
It is placed on the horizontal wall 30 of. This developing device 12 includes a developer tank 31 and a toner supply tank 32, which are partitioned by a partition wall 34 provided in a casing 33, and a communication hole 35 is formed in the bottom so that only the bottom can communicate with each other. 36 is a toner remaining amount detector. The toner in the toner replenishing tank 32 is supplied into the developer tank 31 by a toner replenishing roller 37 provided in the communication hole 35 at the bottom, and the developer consisting of toner and carrier is mixed between the first II stirring member 38 and the second stirring member 38.
The toner is conveyed to the developing roller 13 while being sequentially agitated by the agitating member 39 . Abutment rollers 40 (see FIG. 3) are rotatably provided at both ends of the shaft 13a of the developing roller 13, and the abutment rollers 40
By being pressed against the photoreceptor drum IO by the pressing member 42 of the attachment/detachment device 41 attached to the developing roller 13, the developing roller 13 is disposed parallel to the photoreceptor drum 10 and close to the photoreceptor drum 10 with a constant gap maintained therebetween. The portion of the casing 33 where the developing roller 10 and the developing roller 13 face each other is an opening 43.
It will be done. Then, the center of the abutting roller 40, that is, the center O1 of the shaft 13a of the developing roller 13, is arranged at a position slightly lower than the center 02 of the photoreceptor drum.
The distance l between 1 and 02 is, for example, several cranes. By doing this, the developing roller 1 is
Even if a force that lifts up the photosensitive drum 10 is applied, the photosensitive drum 10
The upward movement of the photosensitive drum 10 and the developing roller 1 is regulated by the abutment roller 40 in contact with the photosensitive drum 10 and the developing roller 1.
The developing roller 13 does not have an unstable gap with the developing roller 13.
is equipped with a rotary sleeve 46 made of a hollow, non-magnetic material on the outer periphery of a magnet roller 45 in which a plurality of magnets 44 are arranged in the circumferential direction, and the rotary sleeve 46 is attracted to the circumferential surface of the rotary sleeve 46 by the magnet roller 45. The developer is conveyed to the development area A by the rotating sleeve 46 while the spike length is regulated by the spike cutting member 47 . Then, the electrostatic latent image on the photoreceptor drum 10 is developed in the development area A to form a toner image. Note that 48 is a paper feed guide member, and 14 is a static elimination lamp before transfer.

〔Effect of the invention〕

As explained above, according to the present invention, by arranging the center of the abutment roller of the developing device at a position lower than the center of the image carrier, a force that lifts the developer carrier acts on the developer carrier. However, the upward movement is restricted by the abutment roller that is in contact with the image carrier.
The gap between the photosensitive drum and the developer carrier does not become unstable and is maintained constant.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a schematic sectional view of an electrophotographic copying machine, FIG. 2 is a schematic sectional view of a developing device installed in the machine body, and FIG. 3 is a plan view showing the abutting roller portion. It is a diagram. 2 is a document, 10 is a photosensitive drum, 12 is a developing device, 13
is a developing roller, 17 is copy paper, 21 is a fixing device, 27 is a cleaning device, 29 is a machine body, 31 is a developer tank, 32
33 is a toner supply tank, 33 is a casing, 40 is an abutment roller, 41 is an attachment/detachment device, and 42 is a pressing member.

Claims (1)

[Claims] A developer carrier of a developing device is disposed close to the image carrier, and an abutment roller attached to the shaft of the developer carrier contacts the image carrier, thereby causing the image carrier and the developer to contact each other. 1. A recording apparatus in which a constant gap is maintained between the abutment roller and the image carrier, characterized in that the center of the abutment roller is located below the center of the image carrier.