JP2545459Y2 - Position adjustment structure of developing device in image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a position adjusting structure of a developing device in an image forming apparatus such as a copying machine, and more particularly, to a position adjusting structure of a magnetic pole in a developing sleeve.

(Prior Art) In an image forming apparatus such as a copying machine or a printer, an electrostatic latent image formed on a photoreceptor is processed into a visible image by a two-component developer in which a toner and a carrier are mixed. Then, the visible image is transferred onto copy paper and then fixed to obtain a copy.

One type of image forming apparatus is a color copying machine that obtains a color image by superimposing images of different colors on the same copy paper. The schematic configuration will be described with reference to FIG.

This color copier includes a scanner unit 21 for reading a document, an image processing unit 22 for electrically processing an image signal output as a digital signal from the scanner unit 21, and an image recording unit for each color from the image processing unit 22. A printer 23 for forming an image on copy paper based on the information.

The scanner unit 21 includes a lamp 25 that illuminates the document placed on the document table 24 while moving the document in the scanning direction, and a lamp 25.
The optical system includes mirrors 26, 27, and 28 for setting the optical path of the reflected light from the document illuminated by 25, and an imaging lens 29 that is arranged in the optical path and forms an image on the dichroic prism 31. In the scanner unit 21, in the dichroic prism 31, for example, image light as reflected light from a document separated into three types of red R, green G, and blue B receives colors of respective wavelengths. Red light receiver CC
D31R, Green CCD Receiver 31G, Blue Receiver CCD31B
And are converted into digital signals in the photodetector.

The digital signal is output to the image forming processing unit 22, where the processing necessary for image forming exposure described later is performed in the processing unit 22, and the recording information of each color, for example, black (hereinafter, Bk
, Cyan (same, C), magenta (same,
M) and yellow (same as Y) are converted into recording forming signals.

FIG. 3 shows a case where the four colors Bk, C, M and Y are formed, but the number of colors is not limited to this.

The signal from the image processing unit 22 is input to the printer unit 23, and is used for operation control of the image exposure laser light emitting devices 32Bk, 32C, 32M, and 32Y corresponding to each color.

The printer unit 23 exposes the image light from the document onto each photoconductor, processes the electrostatic latent image formed by this exposure with a developer into a visible image, and transfers and fixes it on copy paper.

The printer unit 23 has four recording devices 33Bk, 33C, 33M,
33Y are provided side by side.

Since each recording device has the same configuration, the recording device for C (cyan) will be described for simplicity of description, and the description of the other colors will be omitted. Note that components having the same function for each color are given the same reference numerals, and to distinguish the configuration of each color, reference numerals are added to the reference numerals indicating the colors.

The recording device 33C for cyan has a drum-shaped photosensitive member 34C arranged in the optical path from the laser light emitting device 32C,
Around the photoreceptor 34C, a charging device 35C, a developing device 36C, and a transfer device for performing an image forming process along the rotation direction
37C and the like are arranged similarly to a known copying machine.

The photosensitive member 34C uniformly charged by the charging device 35C forms a latent image of a cyan image by exposure by the laser beam emitting device 32C, and the latent image is processed into a visible image by the developing device 36C.

In the printer unit 23, a copy paper feed unit is provided in two upper and lower stages, and from this feed unit, a feed roller 38
For example, a copy sheet of which one of two sizes is selected is fed, and this copy sheet has its leading end positioned at a registration roller.
After being aligned with the leading end of the image on the photoconductor by 40, the photoconductor is conveyed to the conveyance belt 41 passing through the transfer position of the photoconductor 34C.

The copy paper carried on the conveyor belt 41 and conveyed to the transfer position of the photoconductor 34C is sequentially conveyed toward the photoconductors 34Bk, 34C, 34M, and 34Y, each of which has been subjected to visible image processing, and faces each photoconductor. After the visible images of the respective colors are electrostatically transferred by the operation of the transfer device 37 provided, the transfer belt 37 conveys the visible images to the fixing roller 42, undergoes the fixing process, and discharges the paper.
It is discharged outside the aircraft by 43. The transfer belt 41 is configured to convey the copy paper carried thereon at a moving speed of the belt without displacement by electrostatically adsorbing the copy paper.

In the above-described developing device, for example, when a two-component developer in which a resin toner and a magnetic carrier such as iron powder are mixed is used, a magnetic brush is mounted on a rotatable developing sleeve having a built-in magnet for forming a magnetic brush. It carries the toner and transfers the toner in the brush by electrostatic attraction from the electrostatic latent image on the photoreceptor. Such a developing device has a structure shown in FIG. is there.

The developing device 11 shown in FIG. 4 includes a developing tank 12 in which the developing sleeve 1 is disposed at a lower portion, and a replenishing tank 13 containing replenishing toner. The toner contained in the toner supply layer 13 is rubbed against the surface of the supply roller 15 located near the developing sleeve 1 by the supply roller 14 located at the outlet of the toner supply tank 13, and is carried on the surface of the supply roller 15. It is transported toward the developing sleeve 1. A supply bias circuit 17 for the supply toner is connected to the supply roller 14, the supply roller 15, and the blade 16 for contacting the surface of the supply roller 15 to make the supply toner thinner. 2, the charge amount of the replenishment toner is corrected in accordance with the density change of the reference density pattern i formed thereon.

Multiple magnets, including the magnets that make up the main developing pole,
The main developing pole is attached to the support plate 5 inside the developing sleeve 1, and is provided at a position facing the photoconductor 2 so that the magnetic brush contacts the electrostatic latent image on the photoconductor 2.

The position of the magnet in the developing sleeve, particularly the main developing pole, is extremely important for the visible image processing of the electrostatic latent image on the photoreceptor. There is a possibility that an appropriate contact state cannot be obtained.

Therefore, at the time of assembling the developing device, or after collecting and replacing the toner by rotating the main developing pole for collecting and replacing the toner, the position of the magnet is visually checked while the magnet is being moved. Positioning is performed.

(Problems to be Solved by the Invention) However, at the time of assembling the above-described developing device or after the toner is collected and replaced by rotating the main developing pole, the worker may check the position of the magnet one by one. There is a problem in that the necessity of the necessity increases the assembling time, or it is difficult to accurately determine the position of the magnet due to visual work.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a position adjusting structure capable of accurately positioning a magnet by a simple operation in view of a problem in a conventional developing device assembly.

(Means for Solving the Problems) In order to achieve this object, the present invention provides a magnet body having a plurality of magnetic poles including a developing main pole provided in a developing sleeve of a developing device used in an image forming apparatus. The positioning structure of the above, wherein a rotating shaft having a flat portion formed on a part of its peripheral surface is provided on the magnet body, and the shaft having the flat portion of the rotating shaft is inserted. A boss member formed with a support hole configured to integrate the rotation support shaft in the rotation direction and an arc-shaped long hole centered on the support hole is rotatably provided at an immovable portion. In a part of the direction, a fixing screw insertion portion having a larger hole diameter than the other long hole portion is formed at a position where the state where the developing main pole can face the photoconductor for image formation is formed, and the boss member is rotated. The fixed screw insertion part was facing the screw hole of the fixed part Then, the boss member is fastened and fixed by the fixing screw.

According to the present invention, when the boss member is rotated to fasten the boss member with the fixing screw when the fixing screw insertion portion in the arc-shaped long hole corresponds to the screw hole formed in the immovable portion. The main developing pole of the magnet is fixed at a position facing the photoconductor.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG.

FIG. 1 is an exploded perspective view of a position adjusting structure of a developing device showing an embodiment of the present invention.

In FIG. 1, a developing main pole 3 and a magnetic brush transport magnetic pole 4 which are opposed to a photoreceptor 2 when a developing device is installed in a copying machine are provided in a developing sleeve 1.

Each of the magnets 3 and 4 extends in the axial direction of the developing sleeve 1, and a magnet body is formed by supporting both ends in the longitudinal direction of the developing sleeve 1 with a support plate 5.

At the center of the support plate 5, a base end of a rotation support shaft 6 parallel to the longitudinal direction of the magnet is fixed, and the rotation support shaft 6 forms a flat portion 6A on a part of a peripheral surface on a distal end side thereof. It is. The rotation support shaft 6 is supported by a boss member 7.

The boss member 7 is formed with a hole 7A for inserting and integrating a shaft portion having a plane portion 6A of the rotation support shaft 6, and by inserting the rotation support shaft 6 into the hole 7A, the boss member 7 The rotation support shaft 6 is fixedly supported in the rotation direction.

The boss member 7 is a side plate as an immovable portion of a developing device (not shown) (the immovable portion is not limited to the side plate, and a case or the like is well known. FIG. 1 shows a screw hole 9 provided in the immovable portion, which will be described later). ) Is rotatably inserted into the boss receiving hole provided in the developing sleeve 1, so that the developing sleeve 1 is rotatably supported by the immovable portion via the boss member 7.

An end plate portion 7B having a diameter larger than the boss diameter is formed at an end of the boss member 7 opposite to the side where the rotation support shaft 6 is inserted in the axial direction. Around the hole 7A of the end plate 7B,
An arc-shaped long hole 7C centering on the hole 7A is formed, and at one end thereof, a fixed bolt insertion opening 7D having a larger diameter than other portions is provided. The elongated hole 7C is formed in the boss member 7 by its shape.
The rotation of the end plate portion 7B can be performed only by loosening the fixing bolt 8 without removing it.

The fixing bolt 8 is inserted into the fixing bolt insertion opening 7D and screwed into the screw hole 9 formed in the immovable portion, thereby fastening and fixing the boss member 7 to the immovable portion side. The fixing bolt insertion opening 7D is not limited to a large diameter, but is formed with a countersunk hole. When the fixing bolt 8 inserted into the countersunk hole is provided with a countersunk portion and the fixing bolt 8 is inserted, Automatic alignment may be performed.

The screw hole 9 is provided at a position where a state in which the rotary main shaft 6 is rotated to allow the developing main pole 3 inside the developing sleeve to face the photoconductor 2 is obtained. In this case, the fixing bolt 8 can be inserted, and by setting this correspondence, a state in which the position of the main developing pole 3 in the developing sleeve 1 is opposed to the photosensitive member 2 can be obtained.

When assembling the developing device, particularly when determining the position of the magnet in the developing sleeve 1, for example, if the position of the main developing pole 3 is not facing the photoreceptor 2, it is shown in FIG. As described above, since the fixing bolt insertion hole 7D does not face the screw hole 9 on the immobile portion side, the fixing bolt 8 cannot be tightened.

Then, when the boss member 7 is rotated so that the arc-shaped long hole 7D faces the screw hole 9, the fixing bolt 8 can be inserted and tightened as shown in FIG. 2 (B).
A state in which the main developing pole in the developing sleeve faces the photoconductor 2 is obtained.

(Effects of the Invention) As described above, according to the present invention, a plurality of magnets including a developing main pole are mounted on a support plate, a rotation support shaft is provided at the center of the support plate, and the rotation support shaft is inserted. In the boss member that can rotate integrally with the boss member, an insertion hole for a fixing bolt that can be tightened unless the main developing pole is opposed to the photoconductor is formed, so that the position of the main developing pole is Even if the position is shifted from the position corresponding to the body, the position shift can be corrected only by judging the corresponding relationship between the fixing bolt insertion hole in the boss member and the screw hole on the immovable portion side, so that the assembly work time is reduced. In addition, positioning accuracy can be ensured.

[Brief description of the drawings]

FIG. 1 is a partial perspective view for explaining a position adjusting structure of a developing device according to an embodiment of the present invention, and FIG. 2 is a symbol II in FIG. 1 for explaining an embodiment of the structure shown in FIG. -I
FIG. 3 is a layout view showing an example of the image forming apparatus, and FIG. 4 is a schematic cross section showing the structure of a developing device used in the image forming apparatus shown in FIG. FIG. 1 ... Developing sleeve, 2 ... Photoconductor, 3 ... Developing main electrode
4 ... Magnetic brush transport magnetic pole, 5 ... Support plate, 6 ... Rotating support shaft, 6A ... Flat portion, 7 ... Boss member, 7A ... Rotating support shaft insertion hole, 7B ... End plate portion, 7C: arc-shaped long hole, 7D: fixing bolt insertion hole, 8: fixing bolt, 9: screw hole on the fixed part side.

Claims (1)

(57) [Scope of request for utility model registration] 1. A positioning structure for a magnet body having a plurality of magnetic poles including a developing main pole provided in a developing sleeve of a developing device used in an image forming apparatus, wherein a part of a peripheral surface thereof is flat. A support shaft having a portion formed in the magnet body, and a support hole having a shape for integrating the rotation support shaft in the rotation direction by inserting a shaft portion having the flat portion of the rotation support shaft. And a boss member formed with an arc-shaped long hole centered on the support hole is rotatably provided at an immovable portion, and the developing main electrode is formed in a part of the long hole in the longitudinal direction. A fixing screw insertion portion having a larger hole diameter than other long hole portions is formed at a position where a state facing the body can be set, and the boss member is rotated so that the fixing screw insertion portion faces the screw hole of the immovable portion. At this time, the fastening of the boss member by the fixing screw is performed. Position adjusting structure of the developing device in the image forming apparatus characterized by was Unishi.