JPH0683175A - Developing device for electrophotographic device - Google Patents

Abstract

PURPOSE:To obtain the developing device where the position precision of a thin film forming member to a developing roller is high, the thin film forming member is stably supported and the assembly work supporting the thin film forming member is facilitated. CONSTITUTION:The device is provided with a case 1 for storing toner, the developing roller 4, a holding body 22 disposed along the length direction of the developing roller 4 and consisting of a rigid body and the thin film layer forming member 21 provided in the retaining body 22 and having a contact body 23 triboelectifying the toner while forming toner thin film on a surface of a toner carrier by bringing the member 21 into contact with the surface of the toner carrier. Both edges of the holding body 22 of the thin film forming member 21 are supported to be movable in a straight line in the direction brought close to or separated from the toner carrier.

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 an electrophotographic apparatus.

[0002]

2. Description of the Related Art As a developing device provided in an electrophotographic apparatus, there is one that employs a one-component developing method. In this type of developing device, a thin layer forming member presses non-magnetic one-component toner against the surface of a toner carrier to form a thin layer of toner, and at the same time rubs the toner to electrostatically charge it. FIG. 9 shows an example of a conventional developing device adopting this method.

This developing device is arranged parallel to the photosensitive drum 41. This developing device includes a case 1, an agitator 2, a toner supply roller 3, a developing roller 4 which is a toner (developer) carrier, and a thin layer forming member 5. The case 1 has a length substantially the same as the length of the photoconductor drum 41, has a space portion for accommodating the one-component toner T supplied from the toner pack 12, and has a side facing the photoconductor drum 41. An opening 1a is formed in the portion. A pair of side walls 1a (only one side wall is shown in FIG. 9) on the side of the case 1 that faces the photosensitive drum 41 from the opening 1a.
Are formed at intervals. The case 1 is arranged in parallel with the photosensitive drum 41.

The toner supply roller 3 has a length substantially the same as the length of the photosensitive drum 41, is made of conductive rubber, and is fixed around the metal roller shaft 3a. The toner supply roller 3 is arranged between the side walls 1a of the case 1 in parallel with the photosensitive drum 41, and both ends of the roller shaft 3a are rotatably supported by bearings (not shown) provided on the side wall 1a of the case 1. There is. The developing roller 4 is the photosensitive drum 4.
It has substantially the same length as 1, and is formed of conductive rubber and is fixed around the roller shaft 4a made of metal.

The developing roller 4 is disposed adjacent to and parallel to the toner supplying roller 3, and both ends of the roller shaft 4a are rotatably supported by bearings (not shown) provided on the side wall 1a of the case 1. There is. The developing roller 4 is brought into contact with or close to the peripheral surface of the photosensitive drum 41.

As shown in FIG. 10, the thin layer forming member 5 is in contact with a holder 6 made of a rigid rectangular bar having substantially the same length as the developing roller 4 and made of an elastic material along the length direction thereof. The body 7 is bonded and fixed. Thin layer forming member 5
Is arranged above the developing roller 4 in parallel therewith. The contact body 7 is located on the lower side.

The thin layer forming member 5 is supported as follows. In the figure, 8 is a support member, which has the same length as the thin layer forming member. The thin layer forming member 5 is fitted to the supporting member 8 and is fastened and fixed by the screw 9 at the center portion in the length direction. Both ends of the support member 8 are rotatably supported on the case 1 by pivots 10. A force is applied downward to the support member 8 by a compression coil spring 11 provided in the case 1. As a result, the support member 8 is rotated downward about the pivot 10, and the contact body 7 contacts the peripheral surface of the developing roller 4.

The operation of this developing device is as follows. The toner T in the toner reservoir of the case 1 is conveyed to the toner supply roller 3 by the rotation of the agitator 2. The toner supply roller 3 and the developing roller 4 are rotated by a rotation driving device (not shown). The toner T is attached to the peripheral surface of the developing roller 4 by the toner supply roller 3, and is further pressed against the peripheral surface of the developing roller 4 by the contact body 7 of the thin layer forming member 5. As a result, a thin layer of toner T is formed on the peripheral surface of the developing roller 4. At the same time, the toner T is rubbed and charged. By this charging, the toner T is attracted to the peripheral surface of the photosensitive drum 41 and adheres to the electrostatic latent image formed on the peripheral surface of the photosensitive drum 41 to form a toner image.

In such a developing device, if the toner thin layer on the surface of the developing roller 4 is not sufficiently thin, the charge amount of the toner is reduced, and as a result, the background portion on the electrostatic latent image is developed. A so-called fog phenomenon occurs. For this reason, it is of the utmost importance for the image quality to form the toner thin layer of the developing roller sufficiently thin and uniform. Therefore, it is necessary to bring the thin-layer forming member into uniform and stable contact with the developing roller. Therefore, the structure for supporting the thin-layer forming member is important.

Conventionally, the above-mentioned thin layer forming member 5 is used as the thin layer forming member. Further, instead of the support rod 6 made of a square rod, a configuration using a support rod 6A made of a round rod as shown in FIG. 11 is also considered. 11, the same parts as those in FIG. 10 are designated by the same reference numerals.

[0011]

However, the thin layer forming member 5 having the structure shown in FIGS. 10 and 11 and the structure for supporting the same have the following problems.

That is, since both ends of the supporting member 8 for supporting the thin layer forming member 5 are rotatably supported by the case 1, a shake in the longitudinal direction is likely to occur, and the accuracy of parallelism with the developing roller 4 is high. It's hard to put out. For this reason, it is difficult to secure good parallelism between the contact body 7 of the thin layer forming member 5 supported by the supporting member 8 and the developing roller 4. As a result, the contact body 7 and the developing roller 4 cannot contact each other in parallel, which causes a defective image. This becomes more remarkable as the distance between both ends of the support member 8 increases. Further, the support member 8 is attached to the pivot 10
Assembling work for rotatably supporting the case 1 using the is complicated. The thin layer forming member 5 having the structure shown in FIG. 12 and the structure for supporting the thin layer forming member 5 have the following problems in addition to the above problems.

That is, when the contact body 7 is brought into contact with the developing roller 4, rotation of the developing roller 4 in the direction of arrow A in the figure applies a rotational force in the direction of arrow B in the figure to the support rod 6A. Since the support bar 6A is a round bar and has no surface that restricts rotation in the direction of the arrow B around the center axis thereof, rotation is restricted only by tightening the screw 9. Therefore, when the support rod 6A receives a rotational force, the screw 9 receives the rotational force and is deformed to generate vibration, which causes abnormal noise and image deterioration. It is necessary to make the support member 8 strong by coping with such a phenomenon, which causes an increase in cost.

The present invention has been made in view of the above circumstances, and the positional accuracy of the thin layer forming member with respect to the developing roller is high, the thin layer forming member can be stably supported, and the assembly for supporting the thin layer forming member is further provided. It is an object of the present invention to provide a developing device for an electrophotographic device that is easy to work.

[0015]

In order to achieve the above object, a developing device of an electrophotographic apparatus of the present invention comprises a case for accommodating a developer, a developer carrier, and a longitudinal direction of the developer carrier. A thin holder having a rigid body and a contact body held by the rigid body and contacting the surface of the developer carrier to form a thin layer of the developer and frictionally charging the developer. A layer forming member is provided, and both ends of the holding body are supported so as to be linearly movable in a direction of approaching and separating from the developer carrying body.

[0016]

Since both ends of the holder of the thin layer forming member are supported so as to be linearly movable in the direction of approaching and separating from the developer carrying member, the holding member is less likely to be shaken in the lengthwise direction, and the thin member is thin. It is easy to ensure good parallelism between the contact body of the layer forming member and the developer carrying body. As a result, it is possible to prevent the contact between the contact member and the developer carrying member in parallel with each other and the occurrence of an image defect. Further, the assembling work for supporting the thin layer forming member is easy. Furthermore, even if the holder for the thin layer forming member is a round bar, its rotation can be prevented easily with a simple structure.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention shown in the drawings will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention.
The description will be made with reference to FIG.

FIG. 1 shows the entire developing device and its periphery, and FIG. 2 shows the thin layer forming member and its periphery.
1 and 2, the same parts as those in FIG. 9 are designated by the same reference numerals. That is, 1 is a case, 2 is an agitator, 3 is a toner supply roller, 4 is a developing roller, and 12 is a toner pack. Reference numeral 21 in the figure denotes a thin layer forming member. The thin layer forming member 21 includes a holding body 22 and a contact body 2.
3 and 3.

The holder 22 is a round bar made of a rigid material such as iron or stainless steel, and has a length substantially the same as that of the developing roller 4 in the axial direction. The contact body 23 is made of a synthetic resin having elasticity and has a length substantially the same as that of the holding body 22. The contact member 23 is formed with a protrusion that contacts the peripheral surface of the developing roller 4. The contact body 23 is adhered and fixed to the peripheral surface of the holding body 22 along the length direction.

The thin layer forming member 21 is arranged on the upper side of the developing roller 4 along the lengthwise direction thereof, and is supported by the structure described later. The contact body 23 is located on the lower side.

D-shaped portions 22a having a D-shaped cross section are formed at both ends of the holder 22 of the thin layer forming member 21 so as to project along the length direction. In the figure, 24 is a pair of holders,
Each holder 24 is formed with a D-shaped hole 24a into which the D-shaped portion 22a of the holder 22 can be fitted. Further, in each holder 24, a protrusion 24b is formed on the end surface opposite to the end surface on which the D-shaped hole 24a opens, along the diameter direction of the D-shaped hole 24a.
Are formed respectively. Then, each holder 24 is arranged at both ends of the holding body 22, and 22a of the holding body 22 is fitted into each D-shaped hole 24a. The protrusions 24b of each holder 24 are located along the vertical direction.

Further, on the inner surface of each side wall 1a of the case 1, a linear groove 25 extending in the up-down direction is formed so as to face the portion located above the developing roller 4. The upper and lower ends of each groove 25 are open. The protrusions 24b of the holders 24 fitted to both ends of the holder 22 are inserted into the grooves 25 of the side walls 1a of the case 1 from the upper side and engageable with each other so as to be freely inserted and removed. As a result, both ends of the holder 22 are supported by the case 1 via the holders 24 so as to be linearly movable in the vertical direction, that is, in the direction toward and away from the developing roller 4. The grooves 25 of the case 1 are integrally formed with high precision when the case 1 is molded with synthetic resin.

A downward force is applied to the holder 22 of the thin layer forming member 21 by a compression coil spring 26 arranged on the upper side thereof. The spring 26 is supported by a projecting piece 27 formed on the case 1. As a result, the holder 22
Is applied to the developing roller 4 so that the protrusion of the contact body 23 is pressed against the peripheral surface of the developing roller 4. The thin layer forming member 21 supported in this manner functions to form a thin layer of the toner T on the peripheral surface of the developing roller 4 as described above.

According to the structure of this embodiment, both ends of the holder 22 of the thin layer forming member 21 are supported so as to be linearly movable only in the direction of approaching and separating from the developing roller 4.
The position of the holder 22 is accurately regulated. Therefore, the holding body 22 is less likely to shake in the length direction, and the thin layer forming member 2
It is easy to ensure good parallelism between the first contact body 23 and the developing roller 4. As a result, it is possible to prevent the contact member 23 and the developing roller 4 from contacting in parallel with each other and causing an image defect.

In order to secure the positional accuracy between the contact member 23 and the developing roller 4, the member for movably supporting the holding member 22 is the same as the member for supporting the developing roller 4. In this embodiment, since the developing roller 4 is supported by the case 1, the holder 22 is also supported by the case 1. Further, the work of supporting the thin layer forming member 21 is very simple because the protrusion 24b of each holder 24 is simply inserted into each groove 25 of the case 1.

Further, by fitting the D-shaped portions 22a of the holder 22 and the D-shaped holes 24a of the holder 24, the holder 21 made of a round bar can be easily prevented from rotating with a simple structure. be able to.

The use of the holder 21 made of a round bar has the following advantages. The holder 21 made of a round bar is usually manufactured by a drawing process, but since the internal stress is uniformly applied during the drawing process, the processing accuracy is excellent, and therefore secondary processing such as warpage correction is unnecessary. Further, in the vicinity of the contact portion between the thin layer forming member 21 and the developing roller 4, a wedge-shaped space portion (see FIG. 9) unlike the case of the holding member made of a square bar does not occur, and the conveyance resistance of the toner T is relaxed. Does not cause toner clogging.

Holder 2 made of a round bar of thin layer forming member 21
The configuration for performing the detent 2 is not limited to the above-described embodiment. FIG. 3 shows another example of the detent. That is, the pins 28 protruding in the diametrical direction are provided on the peripheral surfaces of both ends of the holding body 22. The holder 29 has a holder 22.
Is formed with a round hole 29a into which the end of is fitted and a slit 29b with which the pin 28 is engaged. Therefore, the end of the holder 22 is fitted in the round hole 29a of the holder 29, the pin 28 is engaged with the slit 29b, and the holder 22 is prevented from rotating by the holder 29. It should be noted that the holder 29 is formed with a protrusion 29 c that is engaged with the groove 25 of the case 1.

FIG. 4 shows another example of the detent. That is, the holder 30 has the round hole 30a and the slit 3
0b is formed. The end of the holding body 22 is the holder 30.
Is fitted into the round hole 30a of the holder 3 and the end of the contact body 23 is
It is engaged with the 0 slit 30b. Incidentally, 30c is a protrusion formed on the holder 30. In this example, the holder 22 does not need to be specially processed, and the manufacturing cost is low. Also. In this example, the holding body 22 and the contact body 23 may be integrally formed of synthetic resin having excellent slidability.

Further, in all of the above-described embodiments, the holder is used to support the holder 22 on the case 1, but the holder 22 may be directly supported on the groove 25 of the case 1.

In FIG. 5, a recess 31a and a groove 31ba are formed on the inner surface of the side wall 1a of the case 1, the end of the holder 22 is engaged with the recess 31a, and the contact body 23 is engaged with the groove 31b. An example is shown. FIG. 6 shows an example in which the flat portion 32 is projectingly formed at the end of the holding body 22, and the flat portion 32 is engaged with the groove 25 of the case 1.

The holder for the thin layer forming member is not limited to a round bar, but may be a square bar as shown in FIGS. 7 and 8.
7 and 8, the same parts as those in FIG. 2 are denoted by the same reference numerals. In the example shown in FIG. 7, the end portion of the holding body 42 made of a square rod is formed into a case 1 using a square holder 33.
The example supported by is shown. The end of the holder 42 is fitted in the square hole 33a formed in the holder 33, and the protrusion 33b formed in the holder 33 is engaged with the groove 25 of the case 1. The example shown in FIG. 8 is a holder 42 made of a square rod.
Of the groove 34 formed on the inner surface of the side wall 1a of the case 1
Is directly engaged with and supported so as to be freely inserted and removed.

[0033]

As described above, according to the developing device of the electrophotographic apparatus of the present invention, both ends of the holding member of the thin layer forming member are linearly movable in the direction of approaching and separating from the developer carrying member. Since it is supported, it is difficult for the holding body to shake in the lengthwise direction, and it is easy to ensure good parallelism between the contact body of the thin layer forming member and the developer carrying body. It is possible to prevent the occurrence of image defects due to parallel contact with the carrier. In addition, the assembling work for supporting the thin layer forming member is easy, and even if the holding body of the thin layer forming member is a round bar, its rotation can be prevented without difficulty with a simple structure.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a thin layer forming member of the embodiment.

FIG. 3 is a perspective view showing another example of a thin layer forming member.

FIG. 4 is a perspective view showing another example of the thin layer forming member.

FIG. 5 is a perspective view showing another example of the thin layer forming member.

FIG. 6 is a perspective view showing another example of the thin layer forming member.

FIG. 7 is a perspective view showing another example of the thin layer forming member.

FIG. 8 is a perspective view showing another example of the thin layer forming member.

FIG. 9 is a sectional view showing a conventional developing device.

FIG. 10 is an exploded perspective view showing the conventional thin layer forming member.

FIG. 11 is a cross-sectional view showing another example of a conventional thin layer forming member.

[Explanation of symbols]

1 ... Case, 4 ... Developing roller, 21 ... Thin layer forming member, 2
2 ... holding body, 23 ... contact body, 24 ... holder, 25 ... groove.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Nakamura 1-share company, Toshiba Corporation Hino Factory, 3-1, Asahigaoka, Hino City, Tokyo

Claims (1)

[Claims] 1. A case for accommodating a developer, a developer carrying body, a holding body made of a rigid body arranged along a length direction of the developer carrying body, and the developer carrying body held by the holding body. A thin layer forming member having a contact body for frictionally charging the developer while forming a thin layer of the developer on the surface of the body, and both ends of the holding body with respect to the developer carrying body. A developing device of an electrophotographic apparatus, which is supported so as to be linearly movable in a direction of approaching and separating.