JP2001100513A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constitution that a uniform and thin toner layer can be stably formed in specified thickness on a toner carrier over a long term and to provide a developing device capable of maintaining stable image quality by uniformly keeping dimensional relation and contact force between the toner carrier and a photosensitive belt. SOLUTION: The developing device according to this invention is constituted to absorb the shake of the driving shaft of the developing device at the time of turning by providing a 2nd bearing to bear the driving shaft of the developing device in a frame positioned between the developing device and a developing device driving unit in order to uniformly keep the dimensional relation and the contact force between the toner carrier and the photosensitive belt. Thus, uniform image-forming is performed without influencing the toner carrier even when the driving shaft of the developing device is shaken at the time of developing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a developing 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.
Recently, the overall configuration of a developing device has been disclosed in Japanese Patent Application Laid-Open No. H11-133371, for example.

[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 this purpose, it is required to improve the performance of the toner carrier and the toner layer thickness regulating member and to further improve the toner leakage.

In order to develop the toner on the photosensitive belt with uniform image quality, important precision is also required for the dimensional positional relationship between the developing device and the photosensitive belt during development.

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, at the time of development, it is necessary that the toner carrier is rotated while the toner carrier and the photosensitive belt are in contact with a uniform force to develop the toner on the photosensitive belt.

In order to rotate the toner carrier, a rotational power is received from the developing device drive unit. The toner carrier is attached to the toner carrier support shaft via a gear attached to the developing device drive shaft. Receiving rotational power from the gears
The toner carrier is rotated.

At this time, the developing device drive shaft generally has a bearing for supporting it, but it is structurally in a cantilever state, and the developing device and the developing device drive unit are in an assembled state. If the gears are not properly engaged due to differences or dimensional differences, or if the drive shaft of the developing device oscillates, the same effect is exerted on the support shaft of the toner carrier that receives rotational power. The carrier rotates. Therefore, for example, when the toner carrier swings and rotates during development, the dimensional relationship with the photosensitive belt does not become uniform, and the contact force also changes, thereby causing a problem that the image quality cannot be kept uniform. .

An object of the present invention is 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 provide a dimensional relationship between the toner carrier and a photosensitive belt. An object of the present invention is to provide a developing device capable of maintaining a uniform contact force and maintaining stable image quality.

[0013]

In order to achieve the above object, the present invention provides a drive unit for generating rotational power,
A first engagement member mechanically connected to the drive unit; and a second engagement member mechanically connected to the toner carrier on the drive unit side. The rotation is transmitted to the first engagement member by the shaft, and the rotational power of the drive unit is transmitted to the toner carrier by engaging the first engagement member and the second engagement member to rotate the toner carrier. And the drive shaft on the drive unit side is supported at at least two places.

Alternatively, a toner which is a fine colored powder, a toner carrier, and a toner layer thickness regulating member which presses against the toner carrier to frictionally charge the toner and form a thin toner layer on the toner carrier, A developing device for rotating the toner carrier on which the thin toner layer is formed, transporting the thin toner layer to a position opposed to the latent image holding unit on which the electrostatic latent image is formed, and visualizing the electrostatic latent image A second bearing for receiving a developing device drive shaft on a frame positioned between the developing device and the developing device drive unit in order to maintain uniform dimensional positional relationship and contact force between the toner carrier and the photosensitive belt. To absorb the vibration of the drive shaft of the developing device during rotation. As a result, even when the drive shaft of the developing device swings during development, there is no effect on the toner carrier and uniform image formation can be performed.

[0015]

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

FIG. 6 is a sectional view of a compact 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 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. .

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).

Then, 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 transfer of the toner image from the photosensitive belt 2 to the transfer drum 6 is performed by the potential difference.

After passing through the first transfer position 22a, the photosensitive belt 2 is erased of 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.

Thereafter, the remaining toner on the photosensitive belt 2 which has not been transferred in 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. .

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 transport 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

With 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 it is easy to open the transport path, so that a paper jam can be easily handled.

In addition, discharging the printing surface downward at the time of discharging has the 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 shape 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 to be longer in the vertical direction, the space occupied by the photosensitive belt having the same circumference can be reduced, so that the main 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 the arrow 21c, and the photosensitive belt 2 rotates in the direction of the 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 driven with respect to the photosensitive belt 2 so that a configuration with less color shift can be achieved. 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 the direction of the arrow 21b (a method in which the photosensitive belt 2 rotates upward from below in the direction of the photosensitive belt). It is possible to obtain a configuration that is good and has few problems such as vibration.

FIGS. 1, 2, 3, 7, 8, and 9 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 in contact with the photosensitive belt 2 or while maintaining a gap of about 0.1 to 0.3, and is driven as indicated by an arrow 21b.

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 unit 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 between the pressing plates 37.

Further, on both sides of the holding member 36, support portions 36b of the toner carrier 31 are provided. An opening 36c of the support portion 36b is provided with a toner support shaft 31a and a bearing A31b.
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 constituted by one component, and may be attached by separate pieces. However, by using one component, errors during assembly can be reduced. I can do it. 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.

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 and the like of the housing 39.

By inserting the toner carrier unit 38 in the direction of arrow R shown in FIG. 8 and rotating in the direction of arrow S,
As shown in FIG.
9 can be attached.

FIG. 9 is a perspective view showing details of the assembly and configuration of the toner carrier unit 38.

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 fixed to the toner carrier support shaft 31a by a bearing A.
31b, the supporting portions 36 on both sides of the holding member 36
b, the toner carrier unit 38
Is configured.

As shown in FIG. 8, the toner carrier unit 38 is inserted in the direction of the arrow R with the flat portion of the bearing 31b aligned with the opening 39b of the housing 39, and rotated in the direction of the arrow S, whereby the housing 39 is rotated. Supporting part 3
The cylindrical portion 9a and the cylindrical portion of the bearing A31b are engaged with each other, and are finally fixed by fastening the toner carrier unit 31 with screws.

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 formed of an elastic member such as a foamed sponge or a rubber plate, or a sheet-like thin plate.

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 rotatably contacting the side of the toner carrier 31 is disposed on the toner carrier 31, and the toner T adhered to the toner supply roller 32 adheres to the toner carrier 31 to supply the toner. Is done.

A friction regulating member 34 of the toner layer thickness regulating member 34 pressed to a constant pressure by a pressing 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.

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 high, the toner carrier and the toner layer thickness regulating member are regulated. Accurate positioning of the members becomes possible, stable and uniform formation of a thin toner layer becomes possible, image uniformity is 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 or the like due to mounting errors during assembly is small.

Next, the operation of the embodiment of the present invention will be described with reference to FIGS.

The support shaft 31a formed integrally with the toner carrier 31 is engaged with the holding member 36 via a bearing A31b. Also, a toner carrier support shaft
A gear A53 is attached near the end of 31a, which constitutes the developing device 30 as a whole. The developing device drive unit 58 has a bearing B51 on the flange 57 and supports the developing device drive shaft 55. Further, the developing device drive shaft 55
A gear 54 is attached near the end of the. In addition, a frame A50 is located between the developing device 30 and the developing device drive unit 58.

Here, the toner carrier 31 of the developing device 30
Will be described. 4 and 5 show a conventional example. When assembling the small color image forming apparatus shown in FIG.
8 in the direction of the arrow V67, and the gear B54 attached to the developing device drive shaft 55 is shifted to the gear attachment passage hole B66 having a diameter larger than the outer diameter of the gear B54.
The developing device drive unit 58 is attached to the frame A50 via a flange 57 using screws (not shown) or the like, and the gear A attached to the toner carrier support shaft 31a.

In this case, the developing device drive shaft 55 is
Since the developing device drive shaft 55 is rotated, the developing device drive shaft 55 swings, and the meshing of the gears is not uniform, and the toner carrier 31 is moved in the directions A60 and B61. Phenomena occur. For this reason, the contact force between the photosensitive belt 2 and the toner carrier 31 or
The gap interval became non-uniform, which had a bad effect on image quality.

FIG. 1, FIG. 2, and FIG. 3 show one embodiment of the present invention, and a part of the inner periphery of the gear mounting passage hole A56 provided in the frame 50 is apparent from the arrow P59. Thus, the bearing C52 is located. The gear mounting passage hole A56 has a diameter larger than the outer diameter of the gear B54.

The inner diameter of the bearing C 52 is equal to the developing device drive shaft 55.
And the cross-sectional shape is substantially half or less of the circular shape.

Here, when assembling the small color image forming apparatus shown in FIG. 6, first, the developing device driving unit 58 is advanced in the direction of arrow Q62, and the gear B54 attached to the developing device driving shaft 55 Toner support shaft 31a
The developing device drive unit 58 is moved in the direction of the arrow U63 when the developing device drive unit 58 is located at a position where it can be engaged with the gear A53 attached to the developing device. At this time, when the gear A53 and the gear B54 mesh at an appropriate position, the outer periphery of the developing device drive shaft 55 comes into contact with the inner peripheral portion 64 of the bearing C. During rotation, the developing device drive shaft 55 is moved to the bearing C end 65.
, The bearing C52 has a half-moon shape. After the gear A53 and the gear B54 mesh at an appropriate position, the developing device drive unit 58 is attached to the frame A50 via the flange 57 using screws (not shown) or the like.

In this case, when rotating, the developing device drive shaft 55
Is supported by the bearings B51 and C52 to form a double-supported beam, so that the developing device drive shaft 55 does not run out. Therefore, an appropriate rotating force from the developing device driving unit 58 is supplied to the developing device driving shaft 55, the gear B54, and the gear A.
53, the toner carrier 31 is transmitted to the toner carrier 31 via the toner carrier shaft 31a, so that the toner carrier 31 does not swing in the directions A60 and B61, and the photosensitive belt 2 and the toner carrier The contact force of the body 31 or
The gap interval can be kept uniform and uniform image quality can be provided.

[0070]

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 provide a configuration in which the toner carrier and the photosensitive belt are dimensioned. It is possible to provide a developing device capable of maintaining a uniform relationship and contact force and maintaining stable image quality.

[Brief description of the drawings]

FIG. 1 is an essential part cross-sectional view showing a state in which a developing device and a developing device drive unit according to an embodiment of the present invention are appropriately positioned and combined.

FIG. 2 is an essential part cross-sectional view showing an operation for combining the developing device and the developing device driving unit in an appropriate state according to one embodiment of the present invention.

FIG. 3 is a plan view of a main part of the frame.

FIG. 4 is an essential part cross-sectional view showing a state where a conventional developing device and a developing device drive unit are combined.

FIG. 5 is an essential part cross-sectional view showing an operation for combining a conventional developing device and a developing device drive unit.

FIG. 6 is a longitudinal sectional view of a color image forming apparatus according to one embodiment of the present invention.

FIG. 7 is a sectional view of a main part of a developing device according to an embodiment of the present invention.

FIG. 8 is a vertical sectional view of a toner carrier unit and a housing of the developing device according to one embodiment of the present invention.

FIG. 9 is a perspective view showing an assembly and configuration of a toner carrier unit and a housing of the developing device according to one 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 A, 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: frame A, 51: bearing B, 5
2 ... Bearing C, 53 ... Gear A, 54 ... Gear B, 55 ... Developing device drive shaft, 56 ... Gear mounting passage hole A, 57 ... Flange, 58 ... Developing device drive unit, 59 ... Arrow P, 6
0 ... direction A, 61 ... direction B, 62 ... arrow Q, 63 ... arrow U, 64 ... bearing C inner peripheral part, 65 ... bearing C end part, 66 ... gear mounting passage hole B, 67 ... arrow V.

Continuing from the front page (72) Inventor Kazuhiro Wakamatsu 1-1-1 Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Office Information Equipment Division, Hitachi, Ltd. No. 1 Hitachi, Ltd. Office Information Equipment Division (72) Inventor Shoji Takeya 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Office Information Equipment Division (72) Inventor Miyasaka Tohru 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Research Laboratory, Hitachi Ltd. F-term (reference) 2H077 AC04 AD06 AD13 AD17 AD23 BA03 BA08 CA02 FA22 GA13

Claims (6)

[Claims] 1. A toner carrier on which toner is supplied to a surface, a toner layer thickness regulating member for forming a toner layer on the toner carrier, and a toner carrier on which the thin toner layer is formed is rotated. In the developing device, a driving unit that generates rotational power, a first engagement member mechanically connected to the driving unit, and a second engagement member mechanically connected to the toner carrier on the driving unit side. A rotational force of the drive unit is transmitted to the first engaging member by a rotating shaft, and the driving force is generated by engaging the first engaging member and the second engaging member. A developing device for transmitting rotation power of a unit to the toner carrier to rotate the toner carrier, wherein the rotating shaft is supported at at least two places. 2. A developing device according to claim 1, wherein said support at said two places is provided by two bearings. 3. The developing device according to claim 2, wherein at least one of said bearings is provided on a frame. 4. A toner carrier on which toner is supplied to a surface, a toner layer thickness regulating member for forming a toner layer on the toner carrier, and a toner carrier on which the thin toner layer is formed is rotated. In the developing device, a first bearing is provided on a drive shaft on a drive unit side used for rotating a toner carrier of the developing device, and a driving shaft is provided on a frame located between the drive unit and the developing device. A developing device provided with a second bearing for receiving a drive shaft on a unit side. 5. The developing device according to claim 4, wherein a cross-sectional shape of said second bearing is substantially half of a circular shape. 6. The second bearing according to claim 5, wherein the gear mounted on the toner carrier support shaft of the developing device and the gear mounted on the drive shaft engage with each other at an appropriate position. A developing device, wherein an outer periphery of a drive shaft on a drive unit side is in contact with an inner peripheral portion.