JPH11133732A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve maintenance by a simple structure in the handling of a developing device by providing a bearing portion, which fixes a toner supply means for supplying toner to a toner carrier, with oil-containing felt. SOLUTION: A shaft 54 is attached, via a bearing 52 and the oil-containing felt 57, to a toner-scrape-out-member bearing portion 51 which has a part of the developing device 30. Here, when a toner-scrape-out member 41 rotates, toner 50 tends to easily enter the empty space 58 of the toner-scrape-out-member bearing portion 51 due to the provision of an empty space 59. However, on the other hand, it tends to be easily discharged from the empty space 58 of the toner-scrape-out-member bearing portion 51. Also, because the toner-scrape- out-member bearing portion 51 is provided with the oil-containing felt 57, wear due to load is less during rotation, toner 50 is prevented from being fixed firmly due to heat generation, and the phenomenon in which a shaft 54 is locked is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device 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. About.

[0002]

2. Description of the Related Art In a conventional apparatus, 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. There has been known a developing device in which a 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.

[0003] 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 to regulate the friction. A holding member of the toner layer thickness regulating member is fixed to a screw hole of the housing with a screw so that the material contacts 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, means for connecting and supporting the toner carrier and the developer layer thickness regulating means is provided, and their linear expansion coefficients are defined to improve the positioning accuracy. An arrangement is disclosed.

[0006]

In the above prior art, various devices have been devised for the purpose of accurately positioning the toner carrier and the toner layer thickness regulating member and uniformly forming a thin layer.
Various measures have been taken to prevent toner leakage from the developing device case. In recent years, further uniformity of image quality has been demanded for high image quality and high definition.

To this end, the performance of the toner carrier and the toner layer thickness regulating member is improved, and further improvement against toner leakage is achieved.
It is required to improve the reliability of the developing device.

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, a toner supply roller and a toner scraping member are used as a means for supplying the toner to the toner carrier and the toner layer thickness regulating member. A sponge seal is provided to prevent toner from entering the bearing portion.

However, when the toner that has entered the sponge seal portion rotates, the sponge seal wears due to a load during rotation, and the heat generated by the sponge seal causes the toner to be fixed, thereby locking the bearing portion holding the toner supply roller and the toner scraping member. Many phenomena occurred.

An object of the present invention is to provide a structure capable of stably forming a uniform thin toner layer with a predetermined thickness on a toner carrier over a long period of time. Another object of the present invention is to provide a developing device with improved image quality.

[0012]

A feature of the present invention is that a toner, which is 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 carrier is placed on the toner carrier. The toner layer thickness regulating member for forming the toner thin layer and the toner carrier on which the toner thin layer is formed are rotated to move the toner thin layer to a position facing the latent image holding unit on which the electrostatic latent image is formed. In the developing device for conveying and visualizing the electrostatic latent image, an oil-impregnated felt is provided in a bearing for fixing a toner supply unit that supplies toner to the toner carrier.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to FIG.

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 body, a transfer device 12, and a recording medium are provided on the left side of the drawing with respect to the photosensitive belt 2. A medium supply device 10 and a fixing device 14 are provided.

On the right side of the drawing, there are arranged developing devices 30Y, 30M, 30C and 30K filled with toners of four different colors.

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 indicated by 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 to form an electrostatic latent image on the photosensitive belt 2.

Thereafter, the electrostatic latent image on the photosensitive belt 2 is visualized as a toner image by being developed by any of the developing devices 30Y, 30M, 30C and 30K, and is sent to the first transfer position 22a. .

The photosensitive belt 2 is supplied with a potential by a power source (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 residual image removing device 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 has not been transferred by the first transfer is removed by the photosensitive member cleaning device 8, and the next toner image can be formed.

The above-described one-cycle operation is performed by the transfer drum 6
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 melted 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 feeding 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 arranging the above, the transport path can be simplified, and since most of the units are disposed inside the main body relative to the transport path, the transport path is closer to the machine frame (outer frame) and the transport path is opened. Therefore, processing for paper jam can be easily performed.

In addition, discharging the printing surface downward at the time of discharging has an advantage that the printing surface is discharged in the 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 body can be downsized.

When the recording medium is conveyed from the lower portion to the upper portion 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, thereby operating 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 photosensitive belt 2 and the toner carrier are rotated by using a reverse rotation developing system (a system in which the toner carrier 31 rotates in the direction of arrow 21b from the lower side to the upper side on the photosensitive belt side). 31 can be operated in the forward direction, and a configuration with good development efficiency and less problems such as vibration can be obtained.

FIGS. 1, 2, 3, 5, 6, 7, and 8 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. The toner carrier 31 of the developing device 30 contacts the photosensitive belt 2 or maintains a gap of about 0.1 to 0.3 and is driven as indicated by an arrow 31b.

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 is pressed against the toner carrier 31 by an appropriate pressing force by a pressing means 35. 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 leaf spring material of the pressing means 35 and a toner layer thickness regulating material 34a.
Alternatively, a rubber plate (urethane rubber, silicon rubber, or the like) 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 36 a of the holding member 36 by being sandwiched by a pressing plate 37.

Further, on both sides of the holding member 36, support portions 36b of the toner carrier 31 are provided. The toner support shaft 31a is engaged with the opening 36c of the support portion 36b via a bearing 31b. 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 support portion 36b of the toner carrier 31 are preferably formed as one component, and may be mounted as separate pieces. However, by using one component, errors during assembly can be reduced. .

Further, the material is desirably made of a metal plate having as small a difference as possible to prevent deformation due to the 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.

Accordingly, 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.
As shown in FIG. 2, the toner carrier unit 38 can be mounted on the housing 39.

FIG. 5 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 sandwiched by the holding plate 37 in the holding portion 36a of the toner layer thickness regulating member 34 of the holding member 36 and fixed by the screw, and the toner carrier 31 is fixed to the toner carrier support shaft 31a. Of the holding member 3 via the bearing 31b.
6, by being engaged with the support portions 36b on both sides.
A toner carrier unit 38 is configured.

As shown in FIG. 3, the toner carrier unit 38 is inserted in the direction of 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 such that a toner supply roller 32 which is rotatably contacted to the side of the toner carrier 31 with respect to the toner carrier 31 is disposed.
The toner T adhered to the toner supply roller 32 adheres to the toner carrier 31 and is supplied.

The friction regulating member 34 of the toner layer thickness regulating member 34, which is pressurized to a constant pressure by a pressurizing means 35 for applying a contact pressure to the toner carrier 31 on the downstream side thereof.
a to form a thin toner layer.

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 off by the rotatable toner scraping member 41, and no excess toner T is accumulated around the toner layer thickness regulating member 34. Appropriate charging of the toner becomes possible.

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 charge amount of the toner of 20 to 30 μC / g could be achieved.

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 with high precision, the toner carrier and the toner layer thickness regulating member can be controlled. Accurate positioning, and stable and uniform formation of a thin toner layer.
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 housing 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 managed with high precision as a single component. And a low price was realized.

FIGS. 7 and 8 show a conventional example. The rotational force from the gear A53 is transmitted to the toner scraping member 41 via a member receiver 55 provided on the shaft A54. Further, the shaft A54 is connected to the developing device 3
0 bearing portion 51 for toner scraping member
Are mounted via a bearing A52 and a sponge seal (1) 61.

A sponge seal (2) 62 is provided between the member receiver 55 and the inner wall 60 of the developing device so as to be in contact with the inner wall 60 of the developing device.

Here, when the toner scraping member 41 rotates, the toner 50 enters the gap (3) 63 from between the inner wall 60 of the developing device and the sponge seal (2) 62, and further the sponge seal (1) 61 Get into it.

When the toner that has entered the sponge seal (1) 61 rotates, the sponge seal (1) is rotated by a load.
As a result, the toner 50 adheres due to the heat generated, and the shaft A54 is locked.

Similarly, the toner supply roller 32 is
The rotational force from the gear B53 is transmitted via the shaft B74.

The shaft B74 is mounted on a toner supply roller bearing 70 having a part of the developing device 30 via a bearing B72 and a sponge seal (3) 78. A sponge seal (4) 79 is provided between the toner supply roller 32 and the developing device inner wall 60 so as to be in contact with the developing device inner wall 60.

Here, when the toner supply roller 32 rotates, the toner 50 enters the gap (6) 80 from between the inner wall 60 of the developing device and the sponge seal (4) 79, and further enters the sponge seal (3) 78. Get into it.

When the toner that has entered the sponge seal (3) 78 rotates, the sponge seal (3) is rotated by a load.
As a result, the toner 50 adheres due to the heat generated, and the shaft B74 is locked.

FIG. 1 and FIG. 6 show an embodiment of the present invention. The toner scraping member 41 includes a shaft A5
Rotational force from the gear A53 is transmitted through the member receiver 55 provided on the fourth member 4.

The shaft A54 is attached to a bearing 51 for a toner scraping member having a part of the developing device 30 via a bearing A52 and an oil-impregnated felt A. A spacer A56 is provided between the member receiver 55 and the inner wall 60 of the developing device, and forms a gap (2) 59.

Here, when the toner scraping member 41 rotates, the toner 50 is provided with the gap (2) 59 so that the gap (1) 58 of the bearing 51 for the toner scraping member is provided.
On the other hand, on the contrary, it is more easily discharged from the gap (1) 58 of the bearing 51 for the toner scraping member.

Further, the bearing 51 for the toner scraping member is provided with the oil-impregnated felt A57, so that when rotating, there is little wear due to the load, the toner 50 does not adhere due to heat generation, and the shaft A54 is locked. This phenomenon can be resolved.

Similarly, the rotational force from the gear B73 is transmitted to the toner supply roller 32 via the shaft B74. Further, a shaft B74 is attached to a toner supply roller bearing 70 having a part of the developing device 30 by a bearing B7.
2. Attached via an oil-impregnated felt B71. A spacer B75 is provided between the toner supply roller 32 and the inner wall 60 of the developing device, and forms a gap (5) 77.

Here, when the toner supply roller 32 rotates, the toner 50 can easily enter the clearance (4) 76 of the toner supply roller bearing 70 by providing the clearance (5) 77. Clearance of part 70 (4)
76, it becomes easier to discharge.

The toner supply roller bearing 70 has
Since the oil-impregnated felt B71 is provided, it is possible to eliminate the phenomenon that the toner 50 is not fixed due to heat generation due to a small amount of wear during rotation and the shaft B74 is locked.

[0082]

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 over a long period of time, and to improve the performance of the toner carrier in a developing device. As a result, the developing device can have a long service life, can be easily cleaned, and can be easily maintained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a bearing portion of a toner scraping member of a developing device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a toner carrier unit and a housing of the developing device according to the embodiment of the present invention.

FIG. 3 is a plan view of a main part 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 perspective view showing an assembly and configuration of a toner carrier unit and a housing of the developing device according to the embodiment of the present invention.

FIG. 6 is a sectional view showing a bearing portion of a toner supply roller of the developing device according to one embodiment of the present invention.

FIG. 7 is a sectional view showing a bearing portion of a toner scraping member of a developing device in a conventional example.

FIG. 8 is a sectional view showing a bearing portion of a toner supply roller of a developing device in a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Machine frame, 2 ... Photosensitive belt, 3 ... Charging device, 4 ... Exposure device, 6 ... Transfer drum, 7 ... After-image removal 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: holding portion, 36b, 39a: supporting portion, 36c, 39b: opening, 37: holding plate, 38: toner carrier unit, 3
9 housing, 40 toner seal member, 41 toner scraping member, 50 toner, 51 bearing portion for toner scraping member, 52 bearing A, 53 gear A, 54
Shaft A, 55: Member receiver, 56: Spacer A, 5
7 ... oil-impregnated felt A, 58 ... gap (1), 59 ... gap (2), 60 ... developing device inner wall, 61 ... sponge seal (1), 62 ... sponge seal (2), 63 ... gap (3), 70 ... Toner supply roller bearing 71, oil-impregnated felt B, 72 bearing B, 73 gear B, 74 shaft B, 75 spacer B, 76 gap (4), 77 gap (5), 78 sponge Seals (3), 79: sponge seal (4), 80: gap (6).

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tadashi Okano 1-1-1 Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Taga Headquarters, Hitachi, Ltd.Electrical Equipment Division (72) Inventor Akira Sasaki Higashitaga, Hitachi City, Ibaraki Prefecture 1-1-1, Machi, Hitachi, Ltd.Electrical Equipment Division, Taga Headquarters (72) Inventor Tetsuro Akasaki 1-1-1, Higashitagacho, Hitachi City, Ibaraki Prefecture, Hitachi, Ltd.Electrical Equipment Division Taga Division (72) Inventor Masafumi Suzaki 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Taga Headquarters, Electrification Equipment Division, Hitachi, Ltd. (72) Inventor Masaharu Takeya 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture (72) Inventor Nobuo Suzuki 1-1-1 Higashitaga-cho, Hitachi City, Ibaraki Pref. Formula company Hitachi electrical appliances Division Taga within headquarters

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 thin toner layer is formed are rotated, and the thin toner layer is transported to a position facing the latent image holding unit on which the electrostatic latent image is formed, and the electrostatic latent image is transferred. A developing device for visualizing, wherein an oil-impregnated felt is provided on a bearing for fixing a toner supply unit for supplying toner to the toner carrier. 2. The developing device according to claim 1, wherein said oil-impregnated felt is provided on a bearing for holding a toner scraping member. 3. The developing device according to claim 2, wherein a gap is formed by providing a spacer between the toner scraping member and an inner wall of the developing device. 4. The developing device according to claim 1, wherein said oil-impregnated felt is provided on a bearing for holding a toner supply roller. 5. The developing device according to claim 4, wherein a gap is formed by providing a spacer between the toner supply roller and an inner wall of the developing device. 6. A developing device according to claim 1, wherein a spacer is provided between said toner supply means and an inner wall of said developing device, and a gap is provided between said inner wall of said developing device and said toner supply means. apparatus.