JPH0460563A - Developing device - Google Patents

Abstract

PURPOSE:To prevent interference from occurring and to eliminate the cause of retention by making the thickness of a sealing member facing to the side of the developing area of a developing sleeve thin so that a gap between the sealing member and the surface of the developing sleeve becomes large. CONSTITUTION:The sealing member K1 is divided to an entrance sealing part K1A covering the developing area and a side sealing part K1B covering the side of the developing area. The thickness (alpha) of the sealing part K1A is made thick to some extent so that the part K1A is deflected and deformed when it is closely brought into contact with a photosensitive body. Besides, by closely bringing it into contact with the photosensitive body, developer is prevented from being splashed toward the photosensitive body. On the other hand, with respect to the sealing part K1A, the thickness of the side sealing part K1B is set to be the same thickness (alpha) as the sealing part K1A within a range that it is extended by the same length as the tip of the sealing part K1A and the thickness (beta) of the range from a position corresponding to the tip of the sealing part K1A to the tip of the sealing part K1B is thinned. Then, the gap between the sealing member K1 and the surface of the developing sleeve B at the side sealing part K1B is made large. Thus, the developer is not retained at the gap of the sealing member K1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a developing device used in a copying machine or the like, and more particularly to a structure for preventing scattering of developer in the developing device.

(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 an image processing section 22 that electrically processes image signals output from the scanner section 21 as digital signals. 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, and 28 that set the optical path of the reflected light from the document illuminated by this lamp 25, and an imaging lens 29 that is disposed in this optical path and forms an image on the dichroic prism 3o. 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 converts the reflected light from the document into three colors, for example, red R, green G, and blue B, that is, the image light, into colors of each wavelength. The light enters the light receivers, that is, the red CCD 31R, the green CCD 31G, and the blue CCD 31B, and is converted into digital signals within the light receivers.

The digital signal described above is output to the image processing section 22,
The processing unit 22 performs the processing necessary for exposure for image formation, which will be described later, to produce recorded information for each color, such as blank (hereinafter abbreviated as Bk), yellow (hereinafter referred to as Bk), magenta (
The signal is converted into a signal for forming recordings of each color, ie, M) and cyan (C).

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

On the other hand, signals from the image processing section 22 are input to the printer section 23 and are used to control the operation of the image exposure laser light emitting devices 328k, 32C132M, and 32Y according to the respective colors.

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 case shown in the figure, the printer section 23 is provided with four sets of recording devices 338k, 33C133M, and 33Y arranged side by side.

Since each of the above-mentioned recording apparatuses has the same configuration, in order to simplify the explanation, only the C (cyan) recording apparatus will be described, and the explanations for the 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 34 on the drum in the optical path from the laser light emitting device 32C.
A charging device 35 is arranged around the photoconductor 34C to perform image forming processing along the rotation direction.
C, 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.
Copy paper having one of the various sizes selected is fed, and the leading edge of the copy paper is aligned with the leading edge of the image by the registration rollers 40, and then placed on the photoreceptor 3.
The direction of the conveyor belt 4I passing through the transfer position C 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. After the visible image of each color is electrostatically transferred by the action of the transfer device 37 provided opposite to the image forming apparatus, the visible image is conveyed from the conveyor belt 41 to the fixing roller 42 where it is fixed, and then transferred to the outside of the machine by the discharge roller 43. is discharged. The above-mentioned transfer belt 41 electrostatically attracts the copy paper it carries, so that the copy paper is transported at the speed of the belt without positional deviation.

The above-mentioned developing device may use, for example, a two-component developer in which a resin toner is mixed with a magnetic carrier such as iron powder. A magnetic brush is supported on a rotatable developing sleeve, and the toner in the brush is transferred by the electrostatic attraction force from the electrostatic latent image on the photoreceptor. has the structure shown in FIG.

That is, the developing device A shown in FIG.
The replenishment toner is supplied to the replenishment roller F located near the developing sleeve B by the supply roller E located at the outlet of the replenishment tank. It is rubbed onto the surface, carried on the surface of the supply roller F, and conveyed toward the developing sleeve B. A replenishment bias circuit H for the replenishment toner is connected to the supply roller E, the replenishment roller F, and the blade G that contacts the surfaces of the replenishment roller F to thin the replenishment toner. The charge amount of the replenishment toner is corrected in accordance with the density change of the reference density pattern i formed on the photoconductor (2).

Inside the above-mentioned developing sleeve B, a plurality of magnets including the magnet constituting the main developing pole are attached to a support plate, and the main developing pole is set at a position facing the photoreceptor (■) and is magnetically The brush is brought into contact with the electrostatic latent image on the photoreceptor.

In addition, in FIG. 5, the reference numeral J indicates a protrusion stretched on the side to form a flat surface for fixing the lid that closes the replenishment port.

On the other hand, the developer carried on the surface of the above-mentioned developing sleeve B is exposed from the opening C1 of the developing tank C, which is formed with a magnetic brush and is formed at a position facing the photoreceptor T, and is exposed above the photoreceptor. By coming into contact with the electrostatic latent image, the toner is electrostatically attracted to the electrostatic latent image.

By the way, in the opening C1 of the developer tank C mentioned above,
As shown in FIG. 6, a doctor blade C2 is provided on the upstream side of the developing sleeve B in the rotational direction, and has a doctor blade C2 that protrudes a part of the developing tank C toward the developing sleeve B. The amount of developer supplied is set by regulating the amount of developer supplied.

(Problem to be Solved by the Invention) However, in the structure of the developing device described above, since the amount of developer on the developing sleeve B is regulated, some developer is removed from the surface of the developing sleeve 8. However, this developer scatters around the opening and leaks from the opening to the outside, that is, to the photoreceptor side, causing background stains on the photoreceptor.

Therefore, as shown in FIG. A sealing member K that can cover the area between the non-development area and the non-development area where
It is conceivable to arrange the developing sleeve B with a part of it in contact with the photoreceptor, with a constant gap between the developing sleeve B and the inner surface of the developing tank facing the developing sleeve B.

However, when such a seal member K is arranged,
While it is advantageous to make the gap between the developing sleeve and the opposing inner surface of the developing tank as narrow as possible in order to prevent toner from scattering due to leakage, it is possible to make this gap as narrow as possible to support the developer in the axial direction of the developing sleeve. If you set it across all areas,
In areas where developer can be held other than the development area, it is difficult to extend the magnet due to the presence of structural parts such as bearings, and this also makes it difficult for magnetic force to reach the area, which makes it difficult for the developer to be used for development. The developer that was not present may move as it is on the developing sleeve and stay between the above-mentioned sealing member and the developing sleeve.

Therefore, the developer that remains in areas other than the development area described above tends to accumulate due to the small influence of the conveying magnetic force on the development sleeve side as described above, and as a result, the accumulated developer, In particular, solidification of the toner may impede the rotation of the developing sleeve or damage the sealing member, causing the toner to scatter.

SUMMARY OF THE INVENTION In view of the problems with the above-mentioned developing device, particularly the toner scattering prevention structure, an object of the present invention is to prevent toner scattering and damage to the sealing member by preventing retention of developer that has not been used for development. An object of the present invention is to obtain a developing device having a structure capable of preventing such problems.

(Means for Solving the Problems) In order to achieve this object, the present invention provides a developing device for processing an electrostatic latent image formed on a photoreceptor into a visible image, which is equipped in the developing device. a developing tank which accommodates a developing sleeve therein and has an opening formed at a position where the developing sleeve faces the photoreceptor; placed,
In addition, in the development area in the axial direction of the development sleeve, the tip is extended to the extent that the developer can be exposed, and in an area to the side of the development area where the developer can be supported, an opening is formed. a sealing member whose distal end is formed in a length capable of covering the entire area of the opposing developing sleeve and extending along the axial direction of the developing sleeve, the sealing member being arranged on the side of the developing area. The structure is characterized in that the thickness of the region that can support developer located at is thinner than that of the region facing the development region.

(Function) According to the present invention, when the developer moving on the side of the development area in the development sleeve reaches the gap between the surface of the development sleeve and the sealing member, the gap is moved in the direction of movement of the developer. Since it is larger than the development area, it moves without interfering with the sealing member.

(Embodiment) Hereinafter, details of an embodiment of the present invention will be explained with reference to FIGS. 1 to 3. Note that in FIGS. 1 to 3, the reference numerals used in FIG. 6 will be used as they are for the components of the developing device.

FIG. 1 is a schematic sectional view for explaining the main parts of a developing device according to an embodiment of the present invention.

That is, in FIG. 1, the developing tank C housing the developing sleeve B is provided with an opening CI at a position where the developing sleeve B and the photoreceptor ■ face each other, and on the inner surface of this opening CI, 1 is disposed on the upstream side in the rotational direction of the developing sleeve B, in other words, on a sealing member whose base end is attached to the rear of the doctor blade C2.

As shown in the second diagram, the sealing member 1 is provided along the axial direction of the developing sleeve B, and the range corresponding to the developing area in the axial direction (for convenience, this range is referred to as the entrance part) is The length of the tip of the magnetic brush formed on the developing sleeve B is set so that it can be exposed toward the photoreceptor 1, and the length of the magnetic brush is set to the side of the developing area (for convenience, this range is the side area). ) has its tip length set so as to cover the circumferential surface of the developing sleeve B facing the opening C1. Therefore, the seal member 1 is divided into an inner seal part KIA that covers the developing area and a side seal part KIB that covers the sides of the developing area.

In the seal member 1, the thickness of the entrance seal part KIA and the thickness of the side seal part KIB are different.

That is, as shown in Figure 3, the thickness α of 1A at the entrance seal portion is set to a certain extent so that it can bend and deform when it comes into close contact with the photoreceptor, and prevents the developer from scattering toward the photoreceptor. This can be prevented by coming into close contact with the photoreceptor.

On the other hand, the side seal part KIB has the same length as the tip of the entrance seal part KIA and has the same thickness α as the entrance seal part KIA, and the side seal part KIB has the same thickness α as the entrance seal part KIA. The thickness β in the range from the position corresponding to the tip of the side seal portion KIA to the tip of the side seal portion KIB is reduced, and the developing sleeve 1 at the side seal portion KIB is made thinner.
8 The distance from the surface has been increased. In other words, the gap between the seal member Kl and the surface of the developing sleeve 18 is wider in the side seal portion KIB than in the area facing the entrance lower seal portion KIA.

Since this embodiment has the above-described structure, after the developer supported on the developing sleeve B passes through the doctor blade C2 in the developing tank C, it is electrostatically charged against the photoconductor (2) in the developing area. It is adsorbed.

On the other hand, on the developing sleeve B facing the above-mentioned side seal part KIB, the developer that did not contribute to development is carried on the developing sleeve B as it is and moves to interfere with the side seal part KIB.

However, since the distance between the side seal portion KIB and the surface of the developing sleeve is wider than the developing area, the developer moves to the seal member 1 without being hindered from moving by the inner surface.

Therefore, the developer supported on the developing sleeve B in the area facing the side seal portion KIB is collected as is without being retained between the developer sleeve B and the seal member Kl.

(Effects of the Invention) As described above, according to the present invention, the sealing member facing the side of the developing area of the developing sleeve on which developer that does not contribute to development is carried is arranged such that the distance between the sealing member and the surface of the developing sleeve is smaller than that of the developing area. Since the thickness is made thinner so that it is larger than that, it is possible to prevent interference between the sealing member and the large amount of residual developer held on the developing sleeve and eliminate the cause of retention. can. Therefore, it is possible to prevent the accumulated developer from being assimilated, thereby preventing rotation of the developing sleeve, damage to the surface of the photoreceptor, or damage to the sealing member.

[Brief explanation of the drawing]

FIG. 1 is a sectional view for explaining the main structure of a developing device according to an embodiment of the present invention, FIG. 2 is a perspective view schematically showing the arrangement of a part of the structure shown in FIG. 1, and FIG. 3 is a perspective view showing a part of the structure shown in FIG. 1, FIG. 4 is a layout diagram for explaining an example of an image forming apparatus, and FIG. FIG. 6 is a schematic cross-sectional view showing the structure of the developing device. FIG. 6 is a cross-sectional view for explaining a part of the structure of the developing device shown in FIG. A: Developing device, B: Developing sleeve, C: Developing tank, CI: Opening, C2: Doctor blade, K1: Seal member, KIA: Opposed to the developing area KIB...Side seal part facing the side of the development area, α...Thickness of the inlet seal part, β...Thickness of the side seal part. (1 other person) Fig. 11 Fig. 3 A Fig. 2 f5 Fig. Fig.

Claims (1)

[Scope of Claims] A developing device for processing an electrostatic latent image formed on a photoreceptor into a visible image, the developing device having a developing sleeve equipped therein, and a developing sleeve equipped with the developing device. a developer tank having an opening formed at a position facing the photoconductor, and a base end attached to the upstream side in the rotational direction of the developing sleeve on the inner surface of the opening,
In addition, in the development area in the axial direction of the development sleeve, the tip is extended to a length that allows the developer to be exposed, and in the area on the side of the development area where the developer can be supported. a sealing member whose distal end is extended to a length capable of covering the entire area of the developing sleeve facing the opening, and the sealing member is arranged to extend over each of these areas, the sealing member being arranged to the side of the developing area. A developing device characterized in that the thickness of a region capable of supporting developer is made thinner than the thickness of a region facing a developing region.