JP3015601B2 - Developing device for electrophotographic equipment - Google Patents

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 apparatus provided in an electrophotographic apparatus, there is an apparatus employing a one-component developing method. The developing device of this system is a system in which a non-magnetic one-component toner is pressed against the surface of a toner carrier by a thin-layer forming member to form a thin layer of toner, and the toner is frictionally charged to charge static electricity. FIG. 9 shows an example of a conventional developing device employing this method.

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

The toner supply roller 3 has substantially the same length as the length of the photosensitive drum 41, is formed of conductive rubber, and is fixed around a metal roller shaft 3a. The toner supply roller 3 is disposed 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. I have. The developing roller 4 is a photosensitive drum 4
1 and is formed of conductive rubber, and is fixed around a roller shaft 4a made of metal.

The developing roller 4 is disposed adjacent to and parallel to the toner supply roller 3, and both ends of a roller shaft 4a are rotatably supported by bearings (not shown) provided on the side wall 1a of the case 1. I have. 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 brought into contact with a holding member 6 made of a rigid square bar having substantially the same length as the developing roller 4 and made of an elastic material along its length. The body 7 is bonded and fixed. Thin layer forming member 5
Is arranged above and parallel to the developing roller 4. Note that the contact body 7 is located on the lower side.

The thin layer forming member 5 is supported as follows. In the figure, reference numeral 8 denotes 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 fixedly fastened by a screw 9 at the center in the length direction. Both ends of the support member 8 are rotatably supported on the case 1 by a pivot 10. A downward force is applied 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 the 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 adhered to the peripheral surface of the developing roller 4 by the toner supply roller 3 and further pressed against the peripheral surface of the developing roller 4 by the contact member 7 of the thin layer forming member 5. As a result, a thin layer of the toner T is formed on the peripheral surface of the developing roller 4. At the same time, the toner T is rubbed and charged. Due to 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 formed sufficiently thin, the charge amount of the toner decreases, and as a result, the background portion on the electrostatic latent image is developed. A so-called fogging phenomenon occurs. For this reason, it is of the utmost importance in terms of image quality to form a sufficiently thin and uniform toner thin layer of the developing roller. Therefore, it is necessary to bring the thin layer forming member into uniform and stable contact with the developing roller. For this reason, a 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, a configuration using a support bar 6A made of a round bar as shown in FIG. 11 instead of the support bar 6 made of a square bar is also considered. 11, the same parts as those in FIG. 10 are denoted 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 the supporting member 8 supporting the thin layer forming member 5 is rotatably supported at both ends by the case 1, it is easy for the longitudinal direction to oscillate, and the precision of the parallelism with respect to the developing roller 4 is improved. It is hard to put out. For this reason, it is difficult to secure good parallelism between the contact member 7 of the thin layer forming member 5 supported by the support member 8 and the developing roller 4. As a result, the contact member 7 and the developing roller 4 cannot contact each other in parallel, which causes an image defect. This is more remarkable as the distance between both ends of the support member 8 increases. Further, the support member 8 is connected to the pivot 10
Is troublesome to assemble and rotatably support the case 1. The thin layer forming member 5 having the configuration shown in FIG. 11 and the structure supporting the thin layer forming member 5 have the following problems in addition to the above problems.

That is, when the contact member 7 is brought into contact with the developing roller 4, a rotation force in the direction of arrow B is applied to the support rod 6A by the rotation of the developing roller 4 in the direction of arrow A. Since the support bar 6A is a round bar and has no surface that restricts rotation in the direction of arrow B about the center axis thereof, the rotation is restricted only by tightening the screw 9. For this reason, when the support rod 6A receives a rotational force, the screw 9 receives the rotational force and is deformed to generate vibration, thereby causing abnormal noise and image deterioration. In order to cope with such a phenomenon, it is necessary to make the support member 8 firmly, which causes an increase in cost.

The present invention has been made in view of the above circumstances, and has high positional accuracy of the thin layer forming member with respect to the developing roller, can stably support the thin layer forming member, and further supports the thin layer forming member. An object of the present invention is to provide a developing device of an electrophotographic apparatus that is easy to operate.

[0015]

In order to achieve the above object, a developing device of an electrophotographic apparatus according to the present invention has a case having a space for accommodating a developer and a pair of side walls located at intervals. A developer carrier disposed between the pair of side walls of the case and supported by the pair of side walls; and a developer carrier arranged along the length direction of the developer carrier between the pair of side walls of the case. A round bar-shaped holding body made of a rigid body, and a contact body that is held by the holding body and that contacts the surface of the developer carrier to form a thin layer of developer and frictionally charges the developer , At the end of the holder, the developer
In the holding body that has received the rotational force accompanying the rotation of the carrier
A thin layer forming member having a detent portion for preventing rotation, and a pair of side walls of the case are formed with straight grooves along a direction approaching and separating from the developer carrier, respectively. It is characterized in that both ends of the holding body are supported in the groove so as to be freely inserted and removed and to be movable.

[0016]

The detents provided at the ends of the holder of the thin layer forming member are supported by grooves formed in a pair of side walls of the case so as to be linearly movable in a direction approaching and separating from the developer carrier. As a result, the contact in the length direction of the holding member is not easily shaken, and good parallelism between the contact member of the thin layer forming member and the developer carrying member is easily secured. As a result, it is possible to prevent the occurrence of an image defect due to the contact body and the developer carrier being in parallel contact. Further, the assembling work for supporting the thin layer forming member is easy. Furthermore, even in the holding body is a round rod-like thin layer forming member, it can be performed without any difficulty the detent with a simple structure, a round bar of coercive by detent by the detent portions
Can stably support the holding body.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIG. 1 shows an embodiment of the present invention.
This will be described 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 denoted 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. In the drawing, reference numeral 21 denotes a thin layer forming member. The thin layer forming member 21 includes the holding body 22 and the contact body 2
3 is comprised.

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 formed of an elastic synthetic resin and has substantially the same length as the holding body 22. The contact body 23 is formed with a protrusion that contacts the peripheral surface of the developing roller 4. The contact body 23 is bonded and fixed to the peripheral surface of the holding body 22 along the length direction.

The thin layer forming member 21 is disposed above the developing roller 4 along the length direction thereof, and is supported by a configuration described later. Note that the contact body 23 is located on the lower side.

At both ends of the holder 22 of the thin layer forming member 21, a D-shaped portion 22a having a D-shaped cross section is formed so as to protrude along the length direction. 24 in the figure 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. Each holder 24 has a protrusion 24b on the end face opposite to the end face on which the D-shaped hole 24a is opened, along the diametrical direction of the D-shaped hole 24a.
Are formed respectively. Each of the holders 24 is disposed at both ends of the holder 22, and the respective D-shaped holes 24a are fitted with the holders 22a. Note that the projections 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 straight groove 25 along the vertical direction (direction of approaching and separating from the developing roller 4) faces a portion located above the developing roller 4. Each is formed. The upper and lower ends of each groove 25 are open. The thin layer forming member 21 is the case 1
Of the thin layer forming member 21
The protrusions 24b of the respective holders 24 fitted to both ends of the holding body 22 provided in the case 1 are inserted into the grooves 25 of the respective side walls 1a of the case 1 from the upper side and engaged with the insertion / removal. As a result, both ends of the holder 22 are supported by the case 1 via the respective holders 24 so as to be linearly movable in the vertical direction, that is, in the direction approaching and separating from the developing roller 4, and the protrusions 2 of the respective holders 24.
4b is combined with the groove 25 of each side wall 1a,
Prevent rotation about its axis.
That is, each holder 24 is provided at an end of the holder 22.
Holder 22 which has received a rotational force associated with the rotation of developing roller 4
It is a detent part that prevents rotation at. Each groove 25 of the case 1 is formed when the case 1 is molded with a synthetic resin.
It is formed with high precision as an integral part.

Further, a downward force is applied to the holding body 22 of the thin layer forming member 21 by a compression coil spring 26 disposed above the holding body 22. The spring 26 is supported by a protruding piece 27 formed on the case 1. Thereby, 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 thus supported acts 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, the detent portions at 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 away from the contact point with respect to the developing roller 4. The position of the holding body 22 is accurately regulated.
For this reason, the holder 22 is unlikely to oscillate in the length direction, and it is easy to secure good parallelism between the contact member 23 of the thin layer forming member 21 and the developing roller 4. Also, the rotation of the developing roller 4
Even if the holding body 22 receives the rotational force from the developing roller 4,
The holding member 22 made of a round bar is rotated by the rotation preventing portion so that
To prevent rotation and stably support the holder 22.
I can have. As a result, it is possible to prevent the occurrence of an image defect due to the contact body 23 and the developing roller 4 contacting in parallel.

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. That is, since the developing roller 4 is supported by the case 1, the holder 22 is also supported by the groove 25 formed in the case 1. In addition, the operation of supporting the thin layer forming member 21 is very simple because only the protrusions 24b of the holders 24 are inserted into the grooves 25 of the case 1.

Further, by fitting each D-shaped portion 22a of the holder 22 and each D-shaped hole 24a of each holder 24, the rotation of the holder 21 made of a round bar can be easily performed 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 drawing, but since the internal stress is uniformly applied at the time of drawing, 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 (see FIG. 9) unlike the case of the holder made of a square bar is not generated, and the transport resistance of the toner T is reduced. Toner clogging does not occur.

Holder 2 made of round bar of thin layer forming member 21
The structure for performing the rotation stop 2 is not limited to the above-described embodiment. FIG. 3 shows another example of the detent. That is, the pins 28 projecting in the diameter direction are provided on the peripheral surfaces at both ends of the holding body 22. The holder 29 includes the holder 22
Is formed with a round hole 29a in which the end of the hole is fitted, and a slit 29b in which the pin 28 is engaged. For this reason, the end of the holder 22 is fitted into the round hole 29 a of the holder 29, the pin 28 is engaged with the slit 29 b, and the holder 22 is prevented from rotating by the holder 29. The holder 29 has a projection 29c 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 holder 22 is the holder 30
Is inserted into the round hole 30a of the
0 is engaged with the slit 30b. Note that reference numeral 30c denotes a protrusion formed on the holder 30. In this example, there is no need to perform special processing on the holder 22, and the manufacturing cost is low. Also. In this example, the holding body 22 and the contact body 23 can be integrally formed of a synthetic resin having excellent slidability.

In all of the embodiments described above, the holder is used to support the holder 22 in the case 1. However, the holder 22 may be directly supported in 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 member 23 is engaged with the groove 31b. An example is shown. FIG. 6 shows an example in which a flat portion 32 is formed to project from an end of the holder 22 and the flat portion 32 is engaged with the groove 25 of the case 1.

The same parts as in FIG. 2 in FIGS. 7 and 8 are shown by the same reference numerals. The example shown in FIG.
An example is shown in which the end of a holder 42 made of a square bar is supported by the case 1 using a square holder 33. Holder 3
The end of the holder 42 is fitted in the square hole 33 a formed in the holder 3, and the protrusion 33 b formed in the holder 33 is engaged with the groove 25 of the case 1. In the example shown in FIG. 8, an end of a holder 42 formed of a square bar is directly engaged with a groove 34 formed on the inner surface of the side wall 1 of the case 1 and is 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 holder of the thin layer forming member are provided in the grooves formed in the pair of side walls of the case. Since it is supported so as to be able to move linearly in the direction approaching and moving away from the holder, it is difficult for the holder to oscillate in the longitudinal direction, and good parallelism between the contact member of the thin layer forming member and the developer carrying member is achieved. As a result, it is possible to prevent the occurrence of image defects due to the contact between the contact body and the developer carrier in parallel. Further, the assembling work for supporting the thin layer forming member is easy, and even if the holder of the thin layer forming member is a round bar, the rotation can be easily prevented with a simple structure. That is, thin
The rotation of the developer carrying member is applied to the end of the holding member constituting the layer forming member.
Prevents rotation of the holder that has received the rotational force associated with rolling
A detent is provided so that a pair of side walls of the case
Both ends of the holder can be freely inserted into and removed from the formed groove
To support the developer carrier as it rotates
Good to stably support thin layer forming members by preventing body rotation
A good image can be formed.

[Brief description of the 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 a 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 a 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 sectional view showing another example of a conventional thin-layer forming member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Case, 4 ... Developing roller, 21 ... Thin layer forming member, 2
2. Holder, 23 Contact, 24 Holder, 25 Groove.

──────────────────────────────────────────────────続 き Continued on the front page (72) Takashi Ishikawa, 3-1-1 Asahigaoka, Hino-shi, Tokyo Inside Toshiba Hino Plant Co., Ltd. (72) Inventor Tetsuya Nakamura 3-1-1, Asahigaoka, Hino-shi, Tokyo Toshiba Hino Factory Co., Ltd. (56) References JP-A-47-12642 (JP, A) JP-A-59-214056 (JP, A) JP-A-3-73980 (JP, A) JP-A-3-140980 (JP, A) Japanese Utility Model 4-40247 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 15/08

Claims (1)

(57) [Claims] 1. A case having a space for accommodating a developer and having a pair of side walls located at intervals.
A developer carrier disposed between the pair of side walls of the case and supported by the pair of side walls; and a rigidity disposed along the length direction of the developer carrier between the pair of side walls of the case. A round bar-shaped holding body made of a body and a contact body that is held by the holding body and contacts the surface of the developer carrier to form a thin layer of the developer while frictionally charging the developer ;
Rotation of the developer carrier at the end of the holder with rotation
Detent for preventing rotation of the holder under force
And a thin layer forming member having a portion, and a pair of side walls of the case are formed with straight grooves along a direction approaching and separating from the developer carrier, respectively. A developing device for an electrophotographic apparatus, wherein both ends are supported so as to be freely inserted and removed and to be movable.