JP2001242701A - Developing blade device and developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the adhesion of toner to a blade and to contribute to excellent image forming in a developing blade device used to form a toner thin layer on a developing roller in cooperation with the developing roller. SOLUTION: This blade device is provided with a supply member 32 supplying lubricant 36 for preventing the adhesion of the toner to the contact surface 34 of the blade 30 arranged near the peripheral surface of the developing roller 16. For example, a lubricant impregnated member is attached to an attaching surface 38 connected to the contact surface 34, and the lubricant 36 oozed out from the impregnated member is supplied to the contact surface 34. It is conceivable to provide the impregnated member at a place opposed to the roller 16 instead.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used for an image forming apparatus using an electrophotographic process, such as a printer and a facsimile.

[0002]

2. Description of the Related Art An image forming apparatus used in an electrophotographic process such as a printer or a facsimile is formed, for example, as shown in FIG. In FIG. 1, a photosensitive drum 4 charged by a charging roller 2 has an L level depending on an image to be printed.
The light is selectively exposed to light from the ED array 6 (or modulated light from a laser (not shown)), and a potential difference is generated between the light and the non-exposed portion, thereby forming an electrostatic latent image. On the other hand, the granular toner 12 poured from the toner cartridge 8 into the toner storage chamber 10 rotates the transport roller 14 disposed in the toner storage chamber 10, contacts the transport roller 14 and the photosensitive drum 4, and contacts the transport roller 14. By the rotation of the developing roller 16 rotating in the same direction, the developing roller 16 is supplied to the photosensitive drum 4 by an electrostatic force applied as described later, and is selectively adhered to the electrostatic latent image to perform development. ,
A toner image is formed on the photosensitive drum 4. Thereafter, the toner image on the photosensitive drum 4 is transferred to the recording paper 20 at a position facing the transfer roller 18. After that, the charging roller 2 is cleaned by the cleaning roller 22 again.
It is charged at a position facing.

As described above, the toner 12 is transported not only by the rotation of the transport roller 14 and the developing roller 16 but also by electrostatic force (Coulomb force). That is, the toner 12 is negatively charged by friction between the transport roller 14 and the developing roller 16, and
A first negative voltage, for example, -480 V is applied to (the shaft), and a negative voltage having a value smaller than the first negative voltage, for example, -240 V, is applied to (the shaft of) the developing roller 16. Then, a potential difference is generated between the surfaces of these two rollers, and the toner 12 adheres to the developing roller 16 by electrostatic force.

At this time, the toner on the developing roller 16 is made uniform (thinned) by a developing blade (doctor blade) 24 before reaching the contact portion with the photosensitive drum 4. That is, the layer of the toner 12 placed on the developing roller 16 as described above is non-uniform and has an excessive thickness. Therefore, the developing blade 24 is pressed from above the developing roller 16 to make the thickness of the layer of the toner 12 an appropriate constant value. Since the toner 12 is negatively charged, in order to prevent the toner 12 from being attracted to the developing blade 24 by an electrostatic force due to a potential difference between the developing roller 16 and the developing blade 24, the developing blade 24 is attached to the shaft of the developing roller 16. Apply the same voltage.

[0005]

As described above, even if a voltage is applied to the developing blade 24, the toner 12 slightly adheres to and accumulates on the developing blade 24, and the amount of accumulation increases as the development is repeated. Further, since a friction is generated between the toner 12, the developing roller 16 and the developing blade 24, a filming phenomenon in which the form of the toner 12 collapses (granules are crushed into a film shape) and adheres to the surface of the developing blade 24 is observed. Will be able to In the developing blade 24 in which the filming phenomenon has occurred, the surface becomes uneven, so that the developing roller 1
Since it is not possible to form a uniform toner layer on the photosensitive drum 6, the adhesion to the photosensitive drum 4 becomes uneven, and the developed image becomes defective. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a developing blade device capable of suppressing toner adhesion and filming.

[0006]

According to a first aspect of the present invention, there is provided a developing blade device which is used to cooperate with a developing roller to make a thickness of a toner layer on the developing roller uniform. A blade that is disposed near the peripheral surface of the developing roller and has a contact surface that contacts the toner on the peripheral surface of the developing roller; and a lubricant that prevents the toner from adhering to the contact surface on the contact surface. And a supply member for supplying. The blade may further include an attachment surface connected to the contact surface, and the supply member may include an impregnation member attached to the attachment surface of the blade and impregnated with a lubricant.

[0007] The developing blade device of the second invention of the present application comprises:
In a developing blade device used in cooperation with a developing roller to uniform the thickness of a toner layer on the developing roller, the developing blade device is disposed near a peripheral surface of the developing roller, and a toner on the peripheral surface of the developing roller is disposed. The contact portion for contacting the toner is formed of an impregnated member impregnated with a lubricant for preventing toner from adhering. The image forming apparatus further includes a blade disposed near the peripheral surface of the developing roller and having a facing surface facing the toner on the peripheral surface of the developing roller, wherein the impregnating member is attached to the facing surface. good. It is arranged near the peripheral surface of the developing roller, between the developing roller,
A blade having a substantially constant gap for determining the thickness of the toner layer may be provided, and the impregnating member may also serve as the blade.

A developing device according to a third aspect of the present invention is a developing blade device used to cooperate with a developing roller to make a thickness of a toner layer on the developing roller uniform, and a peripheral surface of the developing roller. A blade having a contact surface that contacts the toner on the peripheral surface of the developing roller, and a supply member that supplies a lubricant for preventing the toner from adhering to the contact surface on the contact surface. A developing device, further comprising: a mounting surface in which the blade is connected to the contact surface, wherein the supply member is mounted on the mounting surface of the blade, and includes an impregnating member impregnated with a lubricant. Wherein the mounting surface is located above the contact surface and the mounting surface is mounted so as to be close to the developing roller.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a side view showing the developing blade device according to the first embodiment of the present invention.
The overall configuration of the image forming apparatus to which the blade device is attached is, for example, as shown in FIG. In FIG. 1, FIG.
Only the transport roller 14, the developing roller 16 and the developing blade device 24 are shown. Transport roller 14
Is formed by forming a tubular body of foamed rubber on the outer periphery of a metal shaft. The reason why the foamed rubber is used is to improve the toner transport characteristics. The developing roller 16 is formed by forming a cylindrical body of semiconductive elastic rubber on the outer periphery of a metal shaft. As shown in FIG. 4, the developing blade device 24 is attached to a housing 26 of the image forming apparatus via an attaching member 28.

The developing blade device 24 has a metal blade 30 and a lubricant supply member 32. Blade 3
Reference numeral 0 denotes a substantially rectangular shape, the width of which (the direction in which the axis of the developing roller 16 extends, that is, the dimension in the direction perpendicular to the plane of FIG. 1) is substantially equal to the length of the developing roller 16; And a bent portion 30c extending from a lower end 30b of the flat plate portion 30a in a direction substantially perpendicular to the flat plate portion 30a and away from the peripheral surface of the developing roller 16.
And The surface of the flat plate portion 30a on the side of the developing roller 16 forms the flat surface 31, the portion near the lower end forms the contact surface 34, and the upper portion forms the mounting surface 38.
The contact surface 34 is disposed near the peripheral surface of the developing roller 16 and contacts the toner 12 on the peripheral surface of the developing roller 16.

The lubricant supply member 32 is mounted on the mounting surface 38. The lubricant supply member 32 includes the contact surface 3
4, a lubricant 36 for preventing the toner 12 from adhering to the contact surface 34 is supplied, and is formed of an impregnated member impregnated with a lubricant. As the impregnating member, for example, sponge rubber is used. This sponge rubber is
It is a strip extending in the width direction of the blade 30 and desirably extends over the entire width of the blade 30.
For example, a fluorine-modified silicone oil is used as the lubricant because it is necessary that the lubricant does not lower the fluidity of the toner when mixed with the toner. Furthermore, since a high molecular weight material tends to lower the fluidity of the toner, a fluorine-modified silicone oil having an average molecular weight of 50 (for example, FL50 manufactured by Shin-Etsu Silicone Co., Ltd.) is used. The addition amount is, for example, 5 to 30 parts by weight per 100 parts by weight of sponge rubber.

The blade 30 is pressed against the developing roller 16 with a predetermined pressing force, and forms a substantially constant gap between the blade 30 and the developing roller 16 for determining the thickness of the toner layer. It has great rigidity.

With such a configuration, when the developing device is used, the lubricant impregnated in the sponge rubber gradually seeps out, reaches the contact surface 34 along the flat surface 31 of the blade 30, and the lubricant film 40 is formed. Form. As a result, the toner 12
Is less likely to directly contact the blade 30, the toner 12 is less likely to adhere to the blade 30, and the toner 12 once adhered is easily peeled off. Therefore, sticking or accumulation of the toner 12 hardly occurs. Further, the friction between the blade 30 and the toner 12 is reduced, and the frictional heat is suppressed, so that the toner is prevented from being melted or deformed by the frictional heat. As a result, the occurrence of the filming phenomenon of the toner 12 in the developing blade device can be prevented or suppressed.

Further, as described above, since the impregnating member 32 is mounted on the mounting surface 38 provided at a position different from the contact surface 34, there are few restrictions on the dimensions of the impregnating member 32, and a large amount of lubricant can be used. The lubricant can be impregnated, so that the supply of the lubricant can be continued for a long period of time, and the adhesion of the toner and the occurrence of the filming phenomenon can be prevented or suppressed. Further, since the impregnating member 32 is mounted on the mounting surface 38 provided at a position different from the contact surface 34, there is little restriction on the hardness or flexibility of the impregnating member 32, and the most suitable material is mainly used for the impregnation characteristics. You can choose.

Further, as shown in FIG. 1, the lubricant can be reliably supplied to the contact surface by disposing the developing blade device such that the mounting surface of the impregnating member is located above the contact surface. A developing device can be obtained.

The illustrated blade has a flat plate portion 30a and a bent portion 30c, but may have a curved shape instead. Also, other shapes may be used. However, the contact surface and the mounting surface need to be connected, and it is desirable that they are continuous.

Embodiment 2 FIG. FIG. 2 is a side view showing the developing blade device according to the second embodiment of the present invention. The overall configuration of the image forming apparatus to which the blade device is attached is, for example, as shown in FIG. Like FIG. 1, FIG.
4, only the transport roller 14, the developing roller 16, and the developing blade device 44 are shown. The transport roller 14 and the developing roller 16 are configured in the same manner as described with reference to FIG. As shown in FIG. 4, the developing blade device 44 of this embodiment also has a housing 26 of the image forming apparatus.
Is mounted via a mounting member 28.

In the developing blade device 44 of the second embodiment, a portion of the flat surface 31 of the blade 30 similar to the blade 30 of FIG. 1 facing the developing roller 16 constitutes a mounting surface. 46 is attached,
The surface 48 of the lubricant supply member 46 forms a contact surface. The lubricant supply member 46 is formed of an impregnated member impregnated with a lubricant, as in the case of FIG. As the impregnating member, it is preferable to use silicone rubber excellent in the chargeability of the toner, but urethane rubber may be used.

Hereinafter, a method for manufacturing the above impregnated member will be described. First, a semiconductive rubber stock is prepared by mixing a conductive agent such as carbon black into a main raw material rubber such as silicone or urethane. Next, 5 to 30 parts by weight of a lubricant is added to 100 parts by weight of rubber, for example, together with additives such as a cross-linking agent, kneaded, molded into a plate shape, and subjected to pressure and heat treatment. The obtained plate-like rubber is cut into a desired shape and then adhered to a developing blade.

As the lubricant, for example, a fluorine-modified silicone oil having an average molecular weight of 50 (eg, FL50, manufactured by Shin-Etsu Silicone Co., Ltd.) can be used as in the first embodiment. Here, as a comparative example, a fluorine-modified silicone oil having an average molecular weight of 100 (FL100)
When oil was used, oil did not easily exude from the impregnated member, and the effect of the present invention was not sufficiently obtained. From this, it is considered that the oil is retained between the rubber molecules at the beginning of molding, and then gradually leaks to the surface through the space between the rubber molecules. Therefore, if the molecular size (molecular weight) of the oil is larger than the distance between the rubber molecules, the oil does not exude from the rubber, so that the oil used has an average molecular weight of 50 or less. Is desirable. Since there is no difference between the solid rubber and the foamed rubber, the rubber used for the impregnated member may be either solid rubber or foamed rubber. When foamed rubber is used, the foaming agent is added together with the crosslinking agent before kneading.

The impregnating member is a belt-like member extending in the width direction of the developing blade (axial direction of the developing roller 16) as in the case of FIG. 1, and extends over the entire width of the developing blade. desirable. As the developing blade, for example, a metal blade can be used.

With such a configuration, the lubricant impregnated in the solid rubber gradually exudes when the developing device is used. This seepage is promoted by the solid rubber being gradually scraped off by friction with the developing roller. As a result, the lubricant film 50 is formed on the surface 48 of the solid rubber. Therefore, the blade 3 of the toner 12
0 and the lubricant supply member 46 are prevented from adhering, and the toner 12 once adhered is easily peeled off. Therefore, toner 1
2 hardly sticks or accumulates. Also, blade 3
The friction between the toner and the toner 12 is reduced, the frictional heat is suppressed, and the toner is prevented from being melted or deformed by the frictional heat. Also, since the contact part is rubber,
It is softer than a metal blade and has less force applied to the toner from the blade. As a result, the occurrence of the filming phenomenon of the toner 12 in the developing blade device can be prevented or suppressed.

Further, since the lubricant supply member 46 is attached to the portion facing the developing roller 16 as described above, the lubricant that seeps out of the lubricant supply member is effectively used without waste.

Note that a curved blade may be used instead of the blade having the flat plate portion as shown in FIG.

Embodiment 3 FIG. 3 is a side view showing the developing blade device 54 according to the third embodiment of the present invention. The overall configuration of the image forming apparatus to which the blade device 54 is attached is, for example, as shown in FIG. In FIG. 1, FIG.
Of these devices, only the transport roller 14, the developing roller 16, and the developing blade device 54 are shown. Transport roller 14
The developing roller 16 has the same configuration as that of FIG. The developing blade 54 device of this embodiment is also shown in FIG.
As shown in FIG.
8 is attached.

The blade device 54 of the third embodiment has a blade 56, and the blade 56 itself also serves as a lubricant supply member. That is, the blade 56 is formed of an impregnated member impregnated with a lubricant, similarly to the lubricant supply member of FIG. As the impregnating member, for example, as in the second embodiment, it is preferable to use silicone rubber excellent in the chargeability of the toner, but urethane rubber may be used. The blade 56 is pressed against the developing roller 16 with a predetermined pressing force, and forms a substantially constant gap for determining the thickness of the toner layer between the blade 56 and the developing roller 16. It has. As the lubricant, for example, a fluorine-modified silicone oil (for example, manufactured by Shin-Etsu Silicone Co., trade name: F
L50) is used, for example, it is desirable to impregnate 5 to 30 parts by weight with respect to 100 parts by weight of rubber.

With this structure, the lubricant impregnated in the rubber gradually exudes when the developing device is used. This seepage is promoted by the rubber being gradually scraped off by friction with the developing roller. As a result of the lubricant seeping out, a lubricant film 60 is formed on the rubber surface 58. Therefore, the adhesion of the toner 12 to the blade 56 is prevented, and the toner 12 once adhered is easily peeled off. Therefore, sticking or accumulation of the toner 12 hardly occurs. Further, the friction between the blade 56 and the toner 12 is reduced, the frictional heat is suppressed, and the toner is prevented from being melted or deformed by the frictional heat. As a result, the occurrence of the filming phenomenon of the toner 12 in the developing blade device can be prevented or suppressed.

Further, similarly to the second embodiment, the blade 5
Since the lubricant is exuded from 6 itself, the exuded lubricant is effectively used without waste. Further, since the blade also serves as the lubricant impregnated member, the number of parts can be reduced, and failures can be reduced. Further, since the entire blade is formed of the impregnating member, a large amount of the lubricant can be impregnated, and the effect of preventing the toner from adhering can be exhibited for a long period of time.

Although the blade shown in FIG. 3 is curved, it may have a flat plate portion as shown in FIGS.

[0030]

According to the first aspect of the present invention, since the member for supplying the lubricant is provided, the adhesion of the toner to the contact surface can be suppressed, and the image can be formed satisfactorily.

According to the second aspect of the present invention, since the impregnating member is provided at a position different from the contact surface, there are few restrictions on the dimensions of the impregnating member. Therefore, for example, the impregnating member impregnated with a large amount of lubricant is provided. And good adhesion prevention property or peelability can be secured for a long period of time. In addition, since there are few restrictions on the hardness or flexibility of the impregnating member, an optimum material can be selected mainly on the impregnation characteristics.

According to the third aspect of the present invention, since the lubricant exudes from the portion itself in contact with the toner, the exuded lubricant is effectively used.

According to the fourth aspect of the present invention, the blade and the impregnating member can be formed of different materials, respectively, so that an optimum material can be selected according to the respective roles.

According to the fifth aspect of the present invention, the number of components constituting the developing blade device can be reduced, and accordingly, the number of failures can be reduced. Further, since the entire blade is constituted by the impregnating member, a large amount of lubricant can be impregnated, and the effect of preventing the adhesion of the toner can be exhibited for a long period of time.

According to the sixth aspect of the present invention, the lubricant from the lubricant supply member mounted on the mounting surface is reliably supplied to the contact surface.

[Brief description of the drawings]

FIG. 1 is a side view illustrating a developing blade device according to a first embodiment of the present invention, together with a developing roller and a transport roller.

FIG. 2 is a side view illustrating a developing blade device according to a second embodiment of the present invention, together with a developing roller and a transport roller.

FIG. 3 is a side view showing a developing blade device according to a third embodiment of the present invention together with a developing roller and a transport roller.

FIG. 4 is a schematic diagram showing the inside of an image forming apparatus using the developing blade device of the present invention.

[Explanation of symbols]

12 toner, 16 developing roller, 30, 56 blade, 32, 46 lubricant supply member, 34 contact surface, 38 mounting surface.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takao Mizutani 4-11-11 Shibaura, Minato-ku, Tokyo Inside the offshore company data (72) Inventor Masayuki Suzuki 4-11-22 Shibaura, Minato-ku, Tokyo Shares F-term (reference) in company offshore data 2H077 AC04 AD06 AD13 AD17 EA15 GA03

Claims (6)

[Claims] 1. A developing blade device used in cooperation with a developing roller to uniform the thickness of a toner layer on the developing roller, wherein the developing blade device is disposed near a peripheral surface of the developing roller. A developing blade comprising: a blade having a contact surface in contact with a toner on a peripheral surface; and a supply member for supplying a lubricant for preventing the toner from adhering to the contact surface on the contact surface. apparatus. 2. The method according to claim 1, wherein the blade further has an attachment surface connected to the contact surface, and the supply member has an impregnating member attached to the attachment surface of the blade and impregnated with a lubricant. The developing blade device according to claim 1. 3. A developing blade device used for cooperating with a developing roller to uniform the thickness of a toner layer on the developing roller, wherein the developing blade device is disposed near a peripheral surface of the developing roller. The developing blade device, wherein a contact portion of the peripheral surface that contacts the toner is formed of an impregnating member impregnated with a lubricant for preventing toner from adhering. 4. An image forming apparatus, which is arranged near a peripheral surface of the developing roller,
The developing blade device according to claim 3, further comprising a blade having an opposing surface facing the toner on the peripheral surface of the developing roller, wherein the impregnating member is attached to the opposing surface. 5. A blade disposed near the peripheral surface of the developing roller and forming a substantially constant gap for determining the thickness of the toner layer between the developing roller and the developing roller. 4. The developing blade device according to claim 3, wherein the developing blade device also serves as the developing blade device. 6. A blade device according to claim 2, further comprising a developing roller, wherein the mounting surface is located above the contact surface, and the contact surface is mounted so as to be close to the developing roller. Developing device.