JPH03276177A - Method for collecting developer in image forming device - Google Patents

Abstract

PURPOSE:To surely collect developer in a simple method by displacing a necessary main pole in the magnet for forming a magnetic brush of a developing sleeve to a position where the main pole is not opposed to a photosensitive body at the time of collecting the developer and turning the developing sleeve at a necessary rotating speed so that the developer may be collected by centrifugal force. CONSTITUTION:In the case of collecting the developer, the magnet group 6 for bristling the developer on the developing sleeve 2 is turned and moved and the developing main pole 6B opposed to the photosensitive body 5 is displaced to a position where it is not opposed to the photosensitive body 5. By turning the sleeve 2 at such a turning speed that the centrifugal force becomes equal to or exceeds developer adhering force in a state where the effect of magnetic force from a magnetic pole 6B is not received, the developer is surely collected in the simple method.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for collecting developer in an image forming apparatus such as a copying machine.

(Prior Art) As is well known, in image forming apparatuses such as copying machines and printers, an electrostatic latent image formed on a photoconductor is processed using a two-component developer containing a mixture of toner and carrier, for example. A copy is obtained by processing a visible image using a photocopy process, transferring the visible image onto copy paper, and then fixing it.

One of the above-mentioned image forming apparatuses is a color copying machine that obtains a color image by superimposing images of different colors on the same copy paper, and the schematic configuration thereof will now be explained with reference to FIG. 4 as follows. .

That is, this color copying machine includes a scanner section 21 for reading originals, an image processing section 22 that electrically processes image signals output from the scanner section 21 as digital signals, and one image processing section 22. a printer section 2 that forms an image on copy paper based on the image recording information of each color;
3.

The scanner part 21 described above includes a lamp 2 that illuminates the original placed on the original placing table 24 while moving in the scanning direction.
5, mirrors 26, 27, 28 for setting the optical path of the reflected light from the original illuminated by the lamp 25, and an imaging lens 29 disposed in this optical path for forming an image on the dichroic prism 30. It includes a light receiver 31 that separates the reflected light from the document into colors and receives the light for each wavelength. In the above-mentioned scanner part 21, the dichroic prism 30 separates the reflected light from the document into three colors, for example, red R, green G, and blue B, that is, the image light, and separates the colors of each wavelength. The light enters the light receivers that receive the light, that is, the red DCD:oR, the green CCD 31G, and the blue CCD 31B, and is converted into a digital signal within the light receiver.

The digital signal described above is output to the image processing section 22,
The processing unit 22 performs the processing necessary for image forming exposure, which will be described later, to record information of each color, for example, black (hereinafter abbreviated as Bk), yellow (hereinafter referred to as y), magenta (hereinafter referred to as M), The signals are converted into signals for recording each color of cyan (C).

Although FIG. 4 shows the case where the four colors of Bk, Y, M, and C mentioned above are formed, the number of one color is of course not limited to this.

On the other hand, the signal from the image processing section 22 is input to the printer section 23, and is used to control the operation of the 32C532M and 32Y in the image exposure laser light emitting device 328 corresponding to each color.

The printer section 23 described above is a section that exposes image light from a document onto a photoreceptor, processes the electrostatic latent image formed by this exposure into a visible image using a developer, and then transfers it onto copy paper. It is.

That is, in the illustrated case, the printer section 23 is provided with four sets of recording devices @ 338k, 33C, 33M, and 33Y arranged side by side.

Since each of the above-mentioned printing apparatuses has the same configuration, in order to simplify the explanation, the printing apparatus for C (cyan) will now be explained, and explanations for other colors will be omitted. Note that components having the same function in each color layer are given the same reference numerals, and in order to distinguish the configuration of each color, a subscript indicating each color is attached to the reference numeral.

That is, the recording device 33c for C (cyan) includes the photoreceptor 3 on the drum in the optical path from the laser beam emitting device 32C.
4C, and around the photoreceptor 34C there is a charging device l for performing image forming processing along one rotation direction.
35C, a developing device 36C, a transfer device 37C, etc. are provided in the same manner as in a known copying machine.

Then, the photoreceptor 3 is uniformly charged by the charging device 35C.
4C, a cyan latent image is formed by exposure by a laser beam emitting device 32C, and the latent image is processed into a visible image by a developing device 36C.

On the other hand, the printer section 23 is provided with a paper feed section for copy paper, and from this paper feed section, the paper is fed by a paper feed roller 38.

For example, copy paper selected from two sizes is fed, and the leading edge of this copy paper is aligned with the leading edge of the image by the registration rollers 40, and then the transfer position of the photoreceptor 34C is determined. The direction of the conveyor belt 41 passing through is conveyed.

The copy paper carried on the conveyor belt 41 and conveyed to the transfer position of the photoreceptor 34C is sequentially conveyed to the photoreceptors 348k, 34C134M, and 34Y, which have been subjected to visible image processing, and is transferred to each photoreceptor. After the visible images of each color are electrostatically transferred by the action of the transfer device 37 provided opposite to each other, the visible images are conveyed from the conveyor belt 41 to the fixing roller 42, where they are fixed, and then transferred to the outside of the machine by the discharge roller 43. It is discharged. The above-mentioned transfer belt 1-41 electrostatically attracts the copy paper it carries, so that the copy paper is conveyed at the moving speed of the belt without misalignment.

In the above-mentioned developing device, for example, when a two-component developer is used, which is a mixture of resin toner and a magnetic carrier such as iron powder, a rotatable developing sleeve containing a built-in magnet for forming magnetic brushes has a magnetic field. It carries a brush, and the toner in the brush is transferred by electrostatic attraction from the electrostatic latent image on the photoreceptor.

The developer carried and transported by the above-mentioned developing sleeve is discharged from the developing sleeve for replacement when its own charging characteristics deteriorate or when its magnetic characteristics reach the end of its lifespan. ing.

Conventionally, the structure for removing developer has been such that a blade is brought into contact with the surface of the developing sleeve to scrape off the developer, or a developer collection section has been attached opposite the position of minimum magnetic force. There is a structure (for example, JP-A-61.-
67877, Japanese Unexamined Patent Publication No. 63-33764).

(Problem to be Solved by the Invention) However, in the above-mentioned developer recovery structure, a special structure for scraping or a discharge part can only be installed at a position where the magnetic force is minimal, which makes the structure complicated. There was a risk of inviting

SUMMARY OF THE INVENTION In view of the above-mentioned problems with the developer recovery structure, an object of the present invention is to provide a method for recovering developer that can be easily and reliably recovered.

(Means for Solving the Problems) In order to achieve this object, the present invention provides an image forming method that performs visible image processing of an electrostatic latent image on a photoconductor using a developing sleeve equipped with a magnetic brush forming magnet inside. A developer recovery method in an apparatus, which comprises:
When collecting the developer, the main developing pole facing the photoreceptor is moved to a position where it does not face the photoreceptor, thereby minimizing the influence of magnetic force on the photoreceptor, and the developing sleeve is able to generate a centrifugal force greater than the adhesion force of the developer. It is characterized by rotating at a speed that is

(Function) According to the present invention, when collecting the developer, the influence of the magnetic force by the main developing pole is minimized by displacing the main developing pole to a position where it does not face the photoreceptor, and the centrifugal force of the developing sleeve Peel off the developer.

(Embodiment) Hereinafter, details of an embodiment of the present invention will be explained with reference to FIGS. 1 to 3.

FIG. 1 is a sectional view showing the overall structure of a developing device for carrying out a developer recovery method according to an embodiment of the present invention.

That is, in FIG. 1, a developing device 1 includes a developing tank 3 having a developing sleeve 2 therein, and a replenishing tank 4 containing replenishing toner.

The developer tank 3 described above has an opening at a position facing the photoreceptor 5, and a portion of the circumferential surface of the developing sleeve 2 is exposed from this opening. The rotation direction of the developing sleeve 2 is set so that it can move in the same tangential direction as the photoreceptor 5, and a magnet including a main developing pole provided inside the developing sleeve 2 is provided at a position facing the photoreceptor 5. A magnetic brush is formed on the surface of the group 6, and the magnetic brush is made to correspond to the photoreceptor 5.

On the other hand, a supply roller 7 is located at the outlet of the supply toner in the supply tank 4, and this supply roller 7 is connected to the developing sleeve 2.
The replenishment roller 8 is in contact with the replenishment roller 8, which is close to the replenishment roller 8. and,
A blade 9 is brought into contact with the replenishment roller 8 along with the supply roller 7 , and the replenishment toner rubbed and supplied by the supply roller 7 is made into a thin layer by the blade 9 and carried on the surface, and then transferred to the developing sleeve 2 . The direction is designed to be transported.

Further, this replenishment roller 8 is equipped with a clutch 10 that is driven via a control section (not shown), and by turning on the clutch 10 when replenishing toner, it is possible to replenish toner toward the developing sleeve 2. It can be rotated in any direction. In FIG. 1, reference numeral 11 indicates a developer recovery screw, reference numeral 12 indicates a supply screw for applying the recovered developer onto the developing sleeve 2 again, and reference numeral 13 indicates a seal plate. ing.

The magnet group 6 located inside the developing sleeve 2 described above is
It can be rotated around the shaft 6A by a parking mechanism (not shown), and during development, the main developing pole 6B is placed in a position facing the photoreceptor 5, and when collecting the developer, the main developing pole 6B is displaced to a position where it does not face the photoreceptor 5.

The rotation speed of the above-mentioned developing sleeve 2 is controlled by the above-mentioned control section, and during development, it cooperates with the photoreceptor 5 to ensure that sufficient toner is supplied to the electrostatic latent image. On the other hand, when collecting the developer, the main developing pole 6B is displaced to a position where it does not face the photoreceptor 5, and the adhesion force of the developer attached to the surface of the developing sleeve 2 is increased. The speed is set at such a speed that the centrifugal force above is obtained.

Therefore, when the developer is collected, it is not affected by the magnetic force from the main developing pole 6B, and in this state, it is easily scattered from the surface of the developing sleeve 2 by centrifugal force.

Since this embodiment has the above-described structure, when collecting the developer, the magnet group 6 rotates the main developing pole 6B around the shaft 6A to a position where it does not face the photoreceptor 5, and the developing sleeve Since the rotational speed No. 2 is set to a speed at which a centrifugal force greater than the adhesion force of the developer is obtained, the developer adhering to the surface of the developing sleeve 2 is peeled off. For example, if the opening of the developer tank 3 is turned downward, the developer can be dropped and collected more easily.6 (Advantageous Effects of the Invention) As described above, according to the present invention, magnetic brush formation is possible. When collecting the developer, the magnet placed inside the developing sleeve, especially the main developing pole facing the photoreceptor, is moved to a position where it does not face the photoreceptor, and the rotational speed of the developing sleeve is reduced. By setting the speed to a speed at which a centrifugal force greater than the adhesion force of the developer is obtained, recovery of the developer can be realized using only the existing developing sleeve and magnet group.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing the overall configuration of a developing device according to an embodiment of the present invention, FIG. 2 is a partial cross-sectional view for explaining one aspect of the developing device shown in FIG. 1, and FIG. FIG. 2 is a partial sectional view corresponding to FIG. 2 for explaining another aspect of the developing device shown in FIG. 1, and FIG. 4 is a layout diagram showing an example of the image forming apparatus. DESCRIPTION OF SYMBOLS 1...Developing device, 2...Developing sleeve, 3...Developing tank, 4...Replenishment tank, 5...Photoconductor, 6...Magnet group, 6A...Rotating shaft, 6B・・・Development main pole, (and 1 other
name) 1vA Fig. 2jI3 Fig.

Claims (1)

[Scope of Claims] A developer recovery method in an image forming apparatus that performs visible image processing of an electrostatic latent image on a photoreceptor using a developing sleeve equipped with a magnet for forming a magnetic brush therein, the method comprising: forming a magnetic brush; When collecting the developer, the main developing pole facing the photoreceptor is moved to a position where it does not face the photoreceptor to minimize the influence of magnetic force on the photoreceptor, and the developing sleeve is held at a position that is higher than the adhesion force of the developer. A method for recovering a developer in an image forming apparatus, characterized by rotating the developer at a speed that provides a centrifugal force of .