JPH04285978A - Developing device for electrophotographic system - Google Patents

Abstract

PURPOSE:To obtain a compact developing device of a two component developing system with inclination resistibility when the electrophotographic device main body is installed. CONSTITUTION:The developing device 23 is of a compact constitution with a space restricting member 19 installed inside the device. A developer circulating path 24 is formed with this and a frame body 18 provided with a doctor blade part 18a. A toner replenishing device 20 constituted from a toner hopper shaft 21 and a toner cartridge 22 is installed inside the before mentioned space restricting member 19. Therefore, even when the main body is installed inclined, the compact developing device where a superior image quality without any thinning in paper edge part is provided.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a developing device in an electrophotographic two-component developing system that uses toner and carrier mixed and stirred, and particularly relates to (1) improvement of image quality when the main body is installed tilted, (2) developing device This is related to the compactness of the .

0002

2. Description of the Related Art An electrophotographic two-component developing system uses a particle mixture of magnetic carrier and insulating toner, and therefore requires a structure that can uniformly mix and stir the particle mixture. A conventional example will be explained using a cross-sectional view (FIG. 2) of a conventional developing device.

[0003] A rotating sleeve 1 constituting the developer carrying and conveying means is made of a non-magnetic material and houses a fixed mag roll 2 therein. The mag roll 2 is a magnet consisting of multiple magnetic poles. A doctor blade 4 is arranged above the sleeve 1 to regulate the developer 3 on the sleeve 1 to a predetermined thickness. A snake screw (1) that mixes, stirs, and conveys the carrier 3a of the developer 3 and the toner 3b near the bottom of the sleeve 1
5. Snake screws (2) 6 are arranged behind the snake screws (1) 5, respectively. In the gap between the sleeve 1 and the snake screw (1) 5, a substantially U-shaped shielding plate 7 is arranged. The regulated amount of the developer 3 regulated by the doctor blade 4 is placed above the sleeve 1 near the doctor blade 4 using a snake screw (2) 6.
A separator 8 is provided that leads to the side. At the rear of the snake screw (2) 6, a carrier 3a carries the replenishing toner 3b.
There is a toner stirring shaft 9 for quickly mixing the toner.

[0004] The bottom plate 10 is made of a non-magnetic material and contains the developer 3.
It is something that accumulates. Further, a lid 11 is attached to the doctor blade 4.

A toner replenisher 13 for replenishing toner 3b is attached to the developing device 12. The toner replenisher 13 has a hopper shaft 14 made of a foamed elastic material having porous holes for dropping the toner 3b in a fixed amount onto the toner stirring shaft 9 of the developing device 12. A toner cartridge 15 sealed on both sides contains toner 3b, and a toner supply device 1
3, the toner is discharged from the toner discharge port 15a by the toner delivery shaft 16.

In such a developing device 17, if the main body of the electrophotographic apparatus is set to be inclined, the developer 3, which is a particle mixture, will be biased in the direction of inclination. Especially sleeve 1
If the sleeve 1 is tilted in the axial direction, the conveyance capacity of the snake screws (1) 5 and (2) 6 will be unbalanced due to this deviation, and the thickness of the developer 3 in the sleeve 1 will become uneven. Due to the angle, the sheet is not conveyed on the edge side of the sleeve 1, causing problems such as a decrease in image quality such as a magnetic brush not being formed and the edge side of the sheet becoming blurred, and an increase in toner scattering.

[0007] As a technical example regarding the conventional developing device,
JP-A No. 57-108872 "Magnetic brush developing device",
There is Utility Model Application Publication No. 63-100753 ``Developing device''.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device that can reduce toner scattering without degrading image quality due to unevenness of the developer that occurs when the main body of an electrophotographic device is installed at an angle.

Another object of the present invention is to provide a compact developing device for downsizing the main body of an electrophotographic apparatus capable of color printing.

0010

[Means for Solving the Problems] The deviation of the developer that occurs when the main body of an electrophotographic apparatus is installed at an angle is determined by the capacity of the space in which the developer can freely move within the developing device. Therefore, Figure 2
In order to minimize the free movement space above, below, and behind the separator 8, the separator is replaced with a closed space regulating member, and the doctor blade and lid are integrated to form a top plate member. A developer circulation path with a predetermined gap is formed above the space regulating member. In order to make the developing device more compact, a toner supply device consisting of a hopper shaft, toner cartridge, etc. is placed inside the space regulating member, and the doctor blade, lid, and bottom plate are integrally formed by pultrusion molding of aluminum.

[0011]

[Operation] By using the space regulating member and the top plate member for reducing the free movement space of the developer in the developing device, it is possible to significantly reduce the deviation of the developer that occurs when the main body of the electrophotographic apparatus is installed at an inclined angle. As a result, the thickness of the developer at the end of the sleeve does not become thinner or it does not stick to the developer, and a stable magnetic brush can be formed in the axial direction of the sleeve, thereby eliminating deterioration in image quality such as blurring at the end of the paper. Furthermore, toner powder smoke caused by the toner mixing and stirring operation by a snake screw or the like at the rear of the sleeve is no longer discharged outside the developing device from the missing part of the magnetic brush on the sleeve, and toner scattering is also reduced. Since the toner replenishing device is disposed inside the space regulating member, the developing device becomes compact. Furthermore, since the doctor blade, lid, and bottom plate are integrally formed, the number of parts can be reduced, and the number of man-hours such as assembly and adjustment can be reduced.

0012

[Embodiment] An embodiment of the present invention will be explained below with reference to FIG. FIG. 1 shows a cross-sectional view of a developing device embodying the present invention, and the same components as those in the conventional developing device of FIG. 2 are denoted by the same reference numerals.

The sleeve 1, which is a rotary member constituting the developer carrying and conveying means, houses a mag roll 2 which is a fixed member made of a non-magnetic material. The mag roll 2 is a magnet consisting of multiple magnetic poles. A frame 1 having a doctor blade portion 18a above the sleeve 1 for regulating the thickness of the developer 3 on the sleeve 1 to a constant level.
8, and the frame body 18 is approximately U-shaped. A snake screw (1) 5 for mixing, stirring, and conveying the carrier 3a of the developer 3 and the toner 3b, and a snake screw (2) 6 located behind the snake screw (1) 5 are arranged near the bottom of the sleeve 1, respectively. has been done. sleeve 1
A substantially V-shaped shielding plate 7 is disposed in the gap between the snake screw (1) and the snake screw (1) 5. Above the sleeve 1 and near the doctor blade part 18a, the doctor blade part 18a is
There is a space regulating member 19 that guides the regulated developer 3 toward the toner stirring shaft 9 side. A toner replenishing device 20 is disposed within the space regulating member 19. The toner replenishing device 20 includes a hopper shaft 21 made of a foamed elastic material having porous holes for dropping a fixed amount of toner 3b onto the toner stirring shaft 9.
There is. The toner cartridge 22 sealed at both ends contains toner 3b, and when inserted into the toner replenishing device 20, the toner cartridge 22 is scraped out from a toner discharge port 22a by a toner scraping wing 22b.

In the developing device 23 having such a configuration,
An electrostatic latent image formed on the surface of a photoreceptor drum (not shown) by an electrophotographic printing process is formed by a toner 3b of a developer 3 consisting of a carrier 3a and a toner 3b carried and conveyed by a sleeve 1. Be visualized. In this embodiment, the operation will be described in detail using a configuration of the With development system in which the photosensitive drum and the sleeve 1 rotate in the same direction as indicated by the arrows. The snake screws (1) 5 and (2) 6, the hopper shaft 21, and the toner scraping blade 22b rotate counterclockwise in the same direction as the sleeve 1, and the toner stirring shaft 9 rotates clockwise. Snake screw (1) 5 and (2
) 6 are wound in opposite directions, so the developer is transported in opposite directions.

The toner 3b in the toner cartridge 22 is discharged from the toner discharge port 22a by a toner scraping blade 22b. The rotation of the hopper shaft 21 is driven and stopped by a drive motor (not shown) which is turned on and off according to commands from a microcomputer (not shown) in the main body of the electrophotographic apparatus. Through this operation, a fixed amount of toner is dropped and replenished only when requested by the microcomputer, mixed and stirred with the carrier 3a of the developer 3 by the toner stirring shaft 9, and further screwed by the snake screw (
2) Stirred at 6 and (1) 5. A part of the developer 3 conveyed from the snake screw (2) 6 to the snake screw (1) 5 is attracted to the magnetic pole S2 of the sleeve 1, and a predetermined thickness of the developer is obtained by the rotational movement of the sleeve 1 and the regulation of the doctor blade 18a. A magnetic brush formed by the layer is formed by the main magnetic pole N1, and when the developing process is completed, the rotation of the sleeve 1 causes the developer 3 to separate from the sleeve 1 due to the arrangement effect of the same magnetic poles S2 and S3 near the snake screw (1) 5, and the snake The screw (1) 5 performs remixing, stirring, and conveyance.

The developer 3 regulated by the doctor blade portion 18a is guided to the toner stirring shaft 9 through a circulation path 24 formed by the space regulating member 19 and the frame 18.

According to this embodiment, even if the main body of the electrophotographic apparatus is installed at an inclination, there is little space in which the developer can move, so that the developer is prevented from shifting in the direction of inclination. Therefore, there are no factors inhibiting the formation of magnetic brushes in the axial direction of the sleeve, and stable development is always performed, resulting in good image quality. Furthermore, since the magnetic brush formation on the sleeve is stable, toner powder smoke is not blown out of the developing device during toner mixing, stirring, and conveying operations, so that it is possible to provide a developing device with extremely little toner scattering.

Furthermore, since the toner replenishing device is housed within the space regulating member, the developing device can be made extremely compact.

[0019]

According to the present invention, even if the main body of the electrophotographic apparatus is installed at an angle, there is only a small space in which the developer can move. Since the brush is stably formed, there is very little toner scattering, and excellent image quality without blurring at the edges of the paper can be obtained, which is effective.

Furthermore, by housing the toner replenishing device within the space regulating member, the developing device can be made extremely compact, making it possible to downsize the main body of the electrophotographic device, especially for color systems consisting of multiple developing devices. This has a remarkable effect on downsizing electrophotographic devices.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a developing device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional developing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Sleeve, 3... Developer, 18... Frame body, 18a... Doctor blade part, 19... Space regulating member, 20... Toner supply device, 21... Toner popper shaft, 22... Toner cartridge, 24... Circulation path.

Claims (3)

[Claims] 1. In an electrophotographic developing device using a two-component developer consisting of a magnetic carrier and an insulating toner, a closed space regulating member is provided behind a sleeve in the developing device;
and a frame integrated with a doctor blade portion that regulates the developer in the sleeve to a predetermined thickness, and the frame and the space regulating member form a developer circulation path at a predetermined interval. An electrophotographic developing device. 2. The electrophotographic developing device according to claim 1, further comprising a toner replenishing device comprising a toner cartridge, a toner hopper shaft, etc., arranged inside the closed space regulating member. 3. An electrophotographic developing device according to claim 1, wherein the doctor blade part, the top plate part, and the bottom plate part storing developer are integrally formed to form a frame.