JPH11133731A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide constitution by which a uniform toner thin layer having specified thickness is stably formed on a toner carrier over a long term and to provide a developing device the maintainability of which is improved at the handling time of the developing device with simple constitution. SOLUTION: In the case of positioning a developing case so that the toner carrier 31 and a toner layer thickness regulating member 34 may be at the lower part of the developing case, the toner carrier 31 and the member 34 form a recessed part with respect to the developing device. Thus, the constitution by which the uniform toner thin layer having the specified thickness is stably formed on the toner carrier 31 over a long term is provided. The developing device capable of realizing easy maintenance, where the toner carrier 31 and the member 34 are not damaged and cleaning work for the device is facilitated, is made small in size and light in weight and inexpensive with the simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing method for visualizing an electrostatic latent image on a photoreceptor by using a toner supplied on a toner carrier as a developer layer having a predetermined thickness by a toner layer thickness regulating member. Related to the device.

[0002]

2. Description of the Related Art In a conventional apparatus, generally, a toner carrier is rotatably supported on a housing of a developing device, and a toner layer thickness regulating member is attached to a holding member of a toner layer thickness regulating member attached to the housing. A developing device is known in which a thickness regulating member is opposed to a toner carrier, and a thin toner layer is formed on the toner carrier by the toner layer thickness regulating member.

The toner layer thickness regulating member is provided with a friction regulating material such as a rubber plate attached to the tip of a plate-like rubber retaining plate, and the rubber retaining plate is attached to the holding member of the toner layer thickness regulating member. The holding member of the toner layer thickness regulating member is screwed and attached to the screw hole of the housing so that the contact member comes into contact with the toner carrier.

Further, as disclosed in JP-A-1-309080, there is disclosed a structure in which a toner carrier is rotatably supported on a housing by a support shaft, and a toner layer thickness regulating member is positioned on the basis of the support shaft. I have. Further, as disclosed in Japanese Patent Application Laid-Open No. 55-89869, there is disclosed a structure in which means for connecting and supporting the toner carrier and the developer layer thickness regulating means are provided, and their linear expansion coefficients are defined to improve positioning accuracy. Have been.

[0005]

In the above prior art, various measures have been devised for the purpose of accurately positioning the toner carrier and the toner layer thickness regulating member so as to form a thin layer uniformly, and to prevent the toner layer from being removed from the developing device case. Various measures have been taken against toner leakage, but in recent years, further uniformity of image quality has been required for higher image quality and higher definition. for that purpose,
It is required to further improve the performance of the toner carrier and the toner layer thickness regulating member and further improve against toner leakage.

In the prior art, a toner carrier and a toner layer thickness regulating member are fixed to a housing by providing a support plate or the like to form a final form.

In such a case, since the toner carrier and the toner layer thickness regulating member are fixed to the housing by providing a support plate or the like, they form an opening. Since it can be easily touched from the outside, the toner carrying member and the toner layer thickness regulating member are often damaged depending on the handling failure. SUMMARY OF THE INVENTION An object of the present invention is to provide a configuration capable of forming a uniform thin toner layer with a predetermined thickness on a toner carrier stably over a long period of time, and to improve maintainability with a simple configuration when handling a developing device. It is another object of the present invention to provide a developing device.

[0008]

In order to achieve the above object, a toner as a fine colored powder, a toner carrier and a toner carrier are pressed against the toner carrier to frictionally charge the toner, and the toner is placed on the toner carrier. Rotating the toner layer thickness regulating member forming the thin layer and the toner carrier on which the toner thin layer is formed,
In a developing device that transports the thin toner layer to a position opposite to the latent image holding unit on which the electrostatic latent image is formed, and visualizes the electrostatic latent image, a toner carrier and the toner layer thickness regulating member include: When the developing case is positioned below the developing case, the toner carrier and the toner layer thickness regulating member are configured to be recessed with respect to the developing device.

For example, a convex portion is provided on one end or both ends of the toner carrier, and the convex portion is protruded from the developing case, or the developing device is formed integrally or separately from the developing case.

As described above, for example, when the developing case is set up so that the toner carrying member and the toner layer thickness regulating member are located below the developing case, the toner carrying member and the toner layer thickness regulating member are flat. Never touch. In addition, during handling, the projections come in contact with the toner carrier and the toner layer thickness regulating member earlier, so that they are not damaged.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a sectional view of a small color image forming apparatus according to the present invention.

This color image forming apparatus is a machine frame (outer frame).
A photosensitive belt 2 serving as a latent image holding means is installed vertically long in a main body constituted by 1, and a transfer drum 6 serving as an intermediate transfer member, a transfer device 12, A medium supply device 10 and a fixing device 14 are arranged, and developing devices 30Y, 30M, 30C, and 30K filled with toners of four different colors are arranged on the right side in the drawing. An exposure device 4 for forming a latent image on the photosensitive belt 2 is disposed below the developing device 30Y, and a paper feed cassette 9 for storing a recording medium is disposed below the exposure device 4.

A transfer device 12, a recording medium peeling device 13, and an intermediate transfer member cleaning device 16 are arranged around the transfer drum 6, and a charging device 3, an afterimage removing device 7, and a photosensitive member cleaning device 8 are arranged around the photosensitive belt 2. Be placed.

The photosensitive belt 2 serving as a latent image holding means is driven in a direction of an arrow 21a by a driving device (not shown).

First, the photosensitive layer on the surface of the driven photosensitive belt 2 is uniformly charged by the charging device 3.

Next, the exposure device 4 exposes the image and character information by a personal computer, an image scanner or the like in dot units, and forms an electrostatic latent image on the photosensitive belt 2. Thereafter, the electrostatic latent images on the photosensitive belt 2 are transferred to the developing devices 30Y and 30Y.
0M, 30C, and 30K, the toner image is visualized as a toner image, and the first transfer position 22
sent to a.

The photosensitive belt 2 is supplied with a potential by a power supply (not shown), and the transfer drum 6 is connected to the ground. Therefore, at the first transfer position 22a, the toner image is transferred from the photosensitive belt 2 to the transfer drum 6 by the potential difference.

After passing through the first transfer position 22a, the photosensitive belt 2 is erased from the electrostatic latent image by light irradiation by the afterimage eraser 7, and the surface potential of the photosensitive belt 2 is reduced to a certain level or less.

After that, the remaining toner on the photosensitive belt 2 which is not transferred by the first transfer is removed by the photosensitive member cleaning device 8, and the next toner image can be formed.

The operation of one cycle described above is performed in synchronization with the timing of one rotation of the transfer drum 6 by the developing devices 30Y and 30Y.
By sequentially performing the processes on M, 30C, and 30K, a multicolor toner image in which a single color toner image is superimposed on the transfer drum 6 is formed.

On the other hand, a recording medium such as a sheet, an OHP sheet, etc.
b, and a single or multiple color toner image formed on the transfer drum 6 is transferred to a recording medium by the operation of the transfer device 12.

After the transfer of the toner image to the recording medium, the recording medium is peeled off from the transfer drum 6 by the recording medium peeling device 13, the toner is fused and fixed by the fixing device 14, and the paper is discharged onto the upper surface of the main body by the paper discharging device 15. You.

On the other hand, after the transfer to the recording medium is completed, the residual toner remaining on the transfer drum 6 without being transferred is cleaned by the intermediate transfer body cleaning device 16 so that the next toner image can be superimposed.

By simplifying the transport path from the supply of the recording medium to the discharge of the recording medium as much as possible and by increasing the radius of curvature of the transport path, paper jams during transport can be prevented and reliability can be improved. .

Further, the processing at the time of paper jam can be easily performed. Further, it can correspond to various types of recording media such as cardboard.

In this embodiment, the recording medium conveyance path is arranged in a substantially arc shape, and the transfer drum 6, the photosensitive belt 2, the developing device 30
By arranging the Y, 30M, 30C, 30K, the exposure device 4 and the like inside the recording medium transport path, the space is effectively used, the body is reduced in size, the transport path is simplified, and the printing surface faces downward when the recording medium is discharged. To discharge to

By adopting the above arrangement, the transport path can be simplified, and most of the units are disposed inside the main body relative to the transport path.
, And the transport route is easily opened, so that a paper jam can be easily handled. In addition, discharging the printing surface downward at the time of discharging has an advantage that the printing surface is discharged in a printing order from the printing surface side.

By forming the photoreceptor in a belt-like configuration, the developing devices 30 of a plurality of colors can be arranged in substantially the same shape on the same plane of the photosensitive belt, and the developing devices can be replaced according to the color to be developed. There is no need to change the structure of the developing device for each color or the like, and the size and the price can be reduced.

Further, by arranging the photosensitive belt 2 vertically long, the space occupied by the photosensitive belt having the same circumference can be reduced, so that the size of the main body can be reduced.

When the recording medium is conveyed from the lower part to the upper part of the main body, the transfer drum 6 rotates in the direction of arrow 21c, and the photosensitive belt 2 rotates in the direction of arrow 21a to operate in the forward direction at each contact point. As a result, it is possible to obtain a configuration with good development efficiency and less problems such as vibration.

Further, the transfer drum 6 can be made to follow the photosensitive belt 2 so that the color shift can be reduced. At this time, the toner carrier 3 which is a toner carrier
1 is a reversal developing method in which the photosensitive belt 2 and the toner carrier 31 are rotated in a direction indicated by an arrow 21b (a method in which the photosensitive belt 2 is rotated upward from the lower side) so that the developing efficiency can be reduced. It is possible to obtain a configuration that is good and has few problems such as vibration.

FIGS. 1, 2, 3, 5, and 6 show an embodiment of the developing device 30 according to the present invention.

The photosensitive belt 2 is driven upward from below in the direction of arrow 21b. Toner carrier 31 of developing device 30
Is driven in the direction indicated by an arrow 31b while in contact with the photosensitive belt 2 or maintaining a gap of about 0.1 to 0.3.

The material of the toner carrier 31 is made of a conductive material such as aluminum or stainless steel or a conductive rubber material.
A toner supply roller 32 and a toner layer thickness regulating member 34 are arranged around the toner carrier 31.

The toner layer thickness regulating member 34 includes a pressing means 35
Thus, the toner carrier 31 is pressed by an appropriate pressing force. The structure of the pressing means 35 is constituted by a leaf spring made of a thin plate such as stainless steel or phosphor bronze.

The friction regulating member 34 of the toner layer thickness regulating member 34
a is a sheet spring material of the pressurizing means 35,
Alternatively, a rubber plate (urethane rubber, silicon rubber, or the like) as a may be attached, or the plate spring material of the pressing means 35 may be stretched to directly contact the toner carrier 31.

The toner layer thickness regulating member 34 is fixed to the holding portion 36a of the holding member 36 by being sandwiched by a pressing plate 37.

Further, support portions 36b of the toner carrier 31 are provided on both sides of the holding member 36. An opening 36c of the supporting portion 36b has a bearing 31b
Is engaged through. The toner carrier 31 and the toner layer thickness regulating member 34 are integrated by a holding member 36 to form a toner carrier unit 38.

Here, the holding member 36 and the supporting portion 36b of the toner carrier 31 are preferably formed as one part, and may be mounted as separate pieces. However, by using one part, errors during assembly can be reduced. . Further, the material is desirably made of a metal plate having a minimum difference in order to prevent deformation due to a difference in linear expansion coefficient from the material of the pressing means 35 of the toner layer thickness regulating member 34.

The housing 39 of the developing device 30 is provided with an opening 39b which is detachable from the support portion 39a of the bearing 31b of the toner carrier unit 38.

Thus, the integrated toner carrier unit 38 is configured to be detachable from the housing 39.

Further, the toner carrier unit 38 is configured to be detachable without disassembling the lid or the like of the housing 39.

By inserting the toner carrier unit 38 in the direction of arrow R shown in FIG. 3 and rotating in the direction of arrow S,
As shown in FIG. 2, the toner carrier unit 38 can be mounted on the housing 39.

FIG. 1 is a perspective view showing the details of the assembly and configuration of the toner carrier unit 38. As shown in FIG.

As described above, the toner layer thickness regulating member 34
Is a holding portion 36 of the toner layer thickness regulating member 34 of the holding member 36.
The toner carrier 31 is sandwiched between the holding plate 37 and fixed by screws.
1b, supporting portions 36b on both sides of the holding member 36
, The toner carrier unit 38 is formed.

As shown in FIG. 3, the toner carrier unit 38 is inserted in the direction indicated by the arrow R with the flat portion of the bearing 31b aligned with the opening 39b of the housing 39.
The support 39 of the housing 39
a and the cylindrical portion of the bearing 31b are engaged with each other, and are finally fixed by fastening the toner carrier unit 31 with screws, so that the developing device 30 is in the final form.

A toner seal member 40 is provided on the housing 39 of the developing device 30 at a position corresponding to the back surface of the toner layer thickness regulating member 34 when the toner carrier unit 38 is attached. The material of the toner seal member 40 is an elastic member such as a foamed sponge or a rubber plate, or a thin sheet.

Further, a toner scraping member 41 is provided to prevent toner stagnation around the toner layer thickness regulating member 34.

The operation of the developing device 30 having the above configuration is as follows.
A toner supply roller 32 that is rotatably contacted to the side of the toner carrier 31 is connected to the toner carrier 31, and the toner T attached to the toner supply roller 32 adheres to the toner carrier 31 to supply toner. Is done. A pressure unit 3 for applying a contact pressure to the toner carrier 31 on the downstream side thereof
5, a toner thin layer is formed by the friction regulating member 34a of the toner layer thickness regulating member 34 pressed to a constant pressure.

Here, the surplus toner T (supply surplus) remaining after the layer thickness is regulated by the toner layer thickness regulating member 34 falls below the layer thickness regulating member 34a.

Thereafter, the excessively supplied toner T is scraped out by the rotatable toner scraping member 41 and no excess toner T is accumulated around the toner layer thickness regulating member 34, so that a stable toner thin layer is always formed. , And proper charging of the toner.

In a printing test of 10,000 sheets using the developing device 30, a long-term stability of a toner layer thickness of 0.42 ± 0.03 mg / cm ² and a toner charge amount of 20 to 30 μC / g could be achieved.

Further, since the toner carrier 31 and the toner layer thickness regulating member 34 are integrated by the holding member 36, if the precision of the components of the holding member 36 is controlled to be higher, the toner carrier and the toner layer thickness regulating member are regulated. Accurate positioning of members becomes possible, and stable and uniform thin toner layer formation becomes possible.
The uniformity of the image can be improved, and high image quality and high definition can be realized.

Further, by integrating the toner carrier 31 and the toner layer thickness regulating member 34 with the holding member 36,
The positioning of the toner carrier 31 and the toner layer thickness regulating member 34 is determined by the holding member 36, so that high precision is not required for the housing 39 for positioning, and the occurrence of torsion and the like due to mounting errors during assembly is small.

In the prior art, the toner carrier and the toner layer thickness regulating member are positioned by the housing.
Since high precision is required for the housing, an expensive resin that can be molded with high precision must be used, and accurate positioning has been performed using a jig or the like during assembly.

However, in the present embodiment, the necessary and sufficient accuracy can be obtained by using a general resin material, and the assembling time can be shortened because the holding member 36 need only be controlled with high precision as a single component. It was able to achieve a low price.

In the figure, a protrusion A5 is attached to a bearing 31b attached to a toner carrier shaft 31a of the toner carrier 31.
1, a projection B52 was provided. As another example, as shown in FIG. 6, a protrusion C53 and a protrusion D54 are provided on both sides of the housing 39.

Accordingly, when the developing device 30 is set up so that the toner carrier 31 and the toner layer thickness regulating member 34 are located below the developing device 30, the protrusions A51,
Since the convex portion B52, or the convex portions C53 and D54 contact the surface first, the toner carrier 31 and the toner layer thickness regulating member 34 are not damaged.

[0060]

According to the present invention, it is possible to provide a structure capable of stably forming a uniform thin toner layer having a predetermined thickness on a toner carrier for a long period of time. A developing device that does not damage the layer thickness regulating member, facilitates the cleaning work of the device, and enables easy maintenance can be realized with a simple configuration, small size, light weight and low price.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an assembly and configuration of a toner carrier unit and a housing of a developing device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the developing device according to the embodiment of the present invention.

FIG. 3 is a vertical sectional view of a toner carrier unit and a housing of the developing device according to the embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a color image forming apparatus according to one embodiment of the present invention.

FIG. 5 is a plan view of a main part of the developing device according to the embodiment of the present invention.

FIG. 6 is a plan view of a main part of a developing device illustrating another embodiment according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Machine frame, 2 ... Photosensitive belt, 3 ... Charging device, 4 ... Exposure device, 6 ... Transfer drum, 7 ... Afterimage removing device, 8 ... Photoconductor cleaning device, 9 ... Paper cassette, 10 ... Paper feeding device , 12 ...
Transfer device, 13: recording medium peeling device, 14: fixing device, 1
5 paper discharge device, 16 intermediate transfer body cleaning device, 21a, 2
1b, 21c: arrow, 22a: first transfer position, 30, 3
0Y, 30M, 30C, 30K: developing device, 31: toner carrier, 31a: toner carrier support shaft, 31b: bearing
32: toner supply roller, 34: toner layer thickness regulating member,
34a: friction regulating material, 36: holding member, 36a, 36b
.. Supporting part, 36c opening, 37 pressing plate, 38 toner carrier unit, 39 housing, 39a supporting part, 39b opening, 40 toner seal member, 41
Toner scraping member, 51: convex portion A, 52: convex portion B, 5
3 ... convex part C, 54 ... convex part D.

Continuing on the front page (72) Tadashi Okano 1-1-1 Higashitaga-cho, Hitachi City, Ibaraki Pref.

Claims (6)

[Claims] 1. A toner layer having a fine color powder, a toner carrier, and a toner layer thickness regulation for pressing the toner carrier and frictionally charging the toner and forming a thin toner layer on the toner carrier. The member and the toner carrier on which the toner thin layer is formed are rotated, the toner carrier and the toner layer thickness regulating member are held in a developing case, and a latent image holding unit on which an electrostatic latent image is formed is provided. In a developing device for transporting a thin toner layer to an opposing position to visualize the electrostatic latent image, the developing case is positioned such that the toner carrier and the toner layer thickness regulating member are located below the developing case. In this case, the toner carrier and the toner layer thickness regulating member are configured so as to be recessed with respect to the developing device. 2. The toner carrier and the toner layer thickness regulating member according to claim 1, wherein the developing case is set up so that the toner carrier and the toner layer thickness regulating member are located below the developing case. A developing device provided with a concave portion so as not to contact a substantially flat surface. 3. The developing device according to claim 1, wherein a convex portion is provided on said toner carrier, and said convex portion protrudes from said developing case. 4. The developing device according to claim 3, wherein said convex portion is provided at one end or both ends of said toner carrier. 5. The developing device according to claim 1, wherein a convex portion is provided on the developing case, and the developing case is formed integrally or separately from the developing case. 6. The developing device according to claim 5, wherein the protrusion provided on the developing case is provided at one end or both ends of the developing case.