JP2001228705A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a more maintenance-free and highly durable developing device which obtains uniform charging with a uniform thin layer, prevents toner from being fixed over time, and has a high durability. SOLUTION: A first regulating member 30 for controlling the amount of toner by a thin metal spring 42 is provided on the upstream side in the rotation direction of an image roller 16 for contacting a photosensitive drum to visualize a latent image, and a rubber elastic member is provided on a downstream side. The second regulating member 34 for forming the toner thin layer 37 on the body 50 is provided, and the toner amount control and the thin layer formation are performed by different regulating members.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device mounted on an electrophotographic apparatus such as a copying machine or a printer, an electrostatic recording apparatus, and the like, and more particularly, to a method in which toner is applied onto a developing roller by a blade-like regulating member. The present invention relates to a non-magnetic one-component developing device provided with a toner thin layer forming means for thinning and charging and carrying the toner.

[0002]

2. Description of the Related Art In recent years, in the field of electrophotographic apparatuses such as copiers, printers, and facsimile machines, especially in the field of small machines, maintenance has been simplified, and a dry type one-component non-magnetic toner developing method has been put into practical use. I have. On the other hand, in an electrophotographic apparatus using the above-described developing method, compared with a developing apparatus using a magnetic two-component toner, toner adheres to a developing roller or a regulating member, causing thin layer unevenness or a variation in charge amount. Has been pointed out that the durability is poor.

To solve these problems, Japanese Patent Application Laid-Open No. 9-809
No. 00 and Japanese Patent Application Laid-Open No. 11-202618, Japanese Patent Application Laid-Open Nos. 8-254892 and 9-62096 disclose improvements in the contact angle and shape when using only silicone rubber or urethane rubber for the regulating member. Improvement of the shape when a stainless steel or phosphor bronze metal sheet is used double or solely as a regulating member, and Japanese Patent Laid-Open No. 6-348119.
And JP-A-8-62974 propose various improvements, such as laminating silicon rubber or urethane rubber to a thin metal plate of stainless steel or phosphor bronze as a regulating member, and disclose a certain effect. .

However, since the elastic blade made of only urethane rubber, silicon rubber, or the like as a restricting member is always in pressure contact with the developing roller, it is plastically deformed over time and has a problem in long-term stability. It has also been reported that when the contact angle is close to 90 °, the toner charge tends to fluctuate, which is insufficient to substantially uniformly adhere the toner.

Further, since the hardness of the regulating member of the thin metal spring is significantly higher than that of rubber, the charge amount of the toner on the developing roller is apt to vary, and when the development is repeated, the contact between the thin metal spring and the developing roller is caused. At the contact portion, so-called filming occurs in which the toner is fused by frictional heat to form a film.
For this reason, it is difficult to make it substantially uniform in a single layer, which causes density unevenness and fog.

Therefore, the developing device is unitized or made into a cartridge, and the toner in the container is consumed, and at the same time, the unit and the cartridge are replaced to stabilize the image quality. However, in recent years, due to increasing interest in environmental issues, demands for longer life of components and units have increased.

[0007]

For this reason, when the developing roller and the regulating member are coated with a fluororesin or a paint for improving the releasability, or when a metal material is used, the surface properties are stabilized. However, these treatments have not been sufficient, and replacement of parts and units has been forced several times before the machine life.

Further, in recent years, the colorization of the electrophotographic apparatus has been rapidly progressing, and in order to achieve a uniform thin layer and uniform charging of the toner due to a demand for higher image quality, the developing roller has a high precision of the initial size of the regulating member. It is becoming necessary to improve the appearance and appearance quality. To this end, surface grinding of the developing roller and high-precision cutting of the regulating member are performed, leading to an increase in the cost of parts.

In view of the various problems, the present invention initially separates the regulating member for controlling the toner amount and the regulating member for forming the thin toner layer into a more uniform thinner. An object of the present invention is to provide a developing device which is more maintenance-free and highly durable, obtains uniform charging in a layer, prevents toner from being fixed over time, and has a higher durability.

[0010]

In order to achieve the above object, a developing device according to the present invention contacts an image carrier in order to visualize an electrostatic latent image on the image carrier into a toner image. Alternatively, in a developing apparatus including a developing roller disposed in close proximity to the developing roller and a toner thin layer forming unit configured to form a thin toner layer on the rotating developing roller, the toner thin layer forming unit may be arranged on the developing roller. First regulating means for contacting a thin metal spring with a developing roller to regulate the amount of toner carried on the developing roller; and a rubber elastic body abutting at a position downstream in the rotation direction from the contact position of the thin metal spring. And a second regulating means for reducing the thickness of the carried toner.

Further, the thin metal spring has a thickness of 0.1 mm.
The rubber elastic body has a thickness of not less than 0.5 mm and not more than 5.0 mm, wherein one side in the longitudinal direction is in contact with the developing roller over the entire length of the developing roller. , Its rubber hardness is more than 30 degrees and 9
It is preferable that the developing roller has a configuration of not more than 0 degree (JIS A) and abutting over the entire length of the developing roller by abutting one edge of the developing roller in the longitudinal direction.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a non-magnetic developing device according to an embodiment of the present invention. FIG. 1 is a schematic view for explaining an embodiment of a one-component non-magnetic developing device using a thin toner layer forming means according to the present invention. The electrostatic latent image formed above is developed into a toner image. A conductive developing roller 16 is rotatably supported in a toner container 14 which is opened opposite to the photosensitive drum 12 by an arrow b.
It is driven to rotate in the direction. Reference numeral 18 denotes a supply roller, which is formed by forming a sponge 20 covered with a rubber skin layer around a metal shaft 22.

The replenishing roller 18 rotating in the direction of arrow c
Is in contact with the surface of the developing roller 16, and the toner 24 in the toner container 14 is uniformly stirred by the toner stirring member 28 supported by the toner container 14 to be pulverized. To the vicinity of the developing roller 16.
The toner 24 carried on the supply roller 18 is rubbed and rubbed at a contact portion between the supply roller 18 and the developing roller 16, receives a triboelectric charge, and adheres to the surface of the developing roller 16 (see FIG. 2).

The developing roller 16 is pivotally supported near the opening of the toner container 14, and the right side in FIG.
4, the photosensitive drum 12 is in contact with the remaining left portion exposed to the outside of the toner container 14. Developing roller 16
Is made of a metal material, or a conductive rubber roller is used.

The toner thin layer forming means for carrying the toner layer on the developing roller 16 is constructed as follows. As shown in a somewhat exaggerated and enlarged manner in FIG.
First, the first restricting means 30 including the thin metal spring 42 is disposed downstream of the replenishing roller 18 in the rotation direction of FIG. The first restricting means 30 presses the longitudinal side surface 32 of the thin metal spring 42 against the developing roller 16 by surface contact and presses the contact portion 3.
3, the tip of the thin metal spring 42 is directed to the upstream side (counter direction) of the developing roller 16 in the rotation direction.
The toner 24 supplied onto the developing roller 16 is controlled to a constant amount.

Next, a second regulating member 34 of a rubber elastic body 50 is disposed downstream of the first regulating member 30 along the rotation direction of the developing roller 16. The free end 35 of the second regulating member 34 is brought into contact with the longitudinal ridge 36 of the strip-shaped rubber elastic body 50 toward the downstream side (trading direction) in the rotation direction of the developing roller 16 so that the toner 24 is The layer is uniformly thinned and triboelectrically charged.

The toner 24 adhering to the developing roller 16 is rubbed by the nip when passing through the regulating members 30 and 34 provided at two places with the rotation of the developing roller 16, and is sufficiently charged by friction. Receive. The single toner layer 37 on the developing roller 16 formed by the nip of the rubber elastic body 50 through the second regulating member 34 is conveyed to the developing section facing the photosensitive drum 12.

Reference numeral 40 denotes a developing bias means. This bias means applies an intermediate bias voltage between the charged potential of the photosensitive drum 12 and the residual potential after optical writing by an exposure unit (not shown). In accordance with the developing electric field between the photosensitive drum potential and the intermediate bias, the charged toner 24 formed in the thin layer 37 on the developing roller 16
The toner image is selectively transferred and adhered to the electrostatic latent image of No. 2 to form a visualized toner image on the photosensitive drum 12. Since this process is known, a detailed description is omitted.

FIG. 3 shows an embodiment of the first regulating member 30 according to the present invention. The thin metal spring 42 used for the first regulating member 30 is a stainless steel material (for example, SUS430) having a thickness of 0.15 mm and cut into a predetermined rectangular shape whose longitudinal side is longer than the developing roller 16. It is fixed to a holder 44 formed of a metal material with a plurality of small screws 46. Then, as shown in FIG. 2, the main body of the non-magnetic developing device 10 is such that the long side surface 32 of the strip is parallel to the tangent line T of the developing roller 16 and the bite amount d1 is 2 mm in the direction of the center C of the developing roller 16. Incorporated in

Reference numeral 56 in FIG. 2 denotes a screw for fixing the holder 44 of the first regulating member 30 to the main body of the non-magnetic developing device 10.
Reference numeral 48 denotes a spacer for adjusting the bite amount. In the case where the machine direction is cut longitudinally from the roll stock and the flat plate of the thin metal spring 42 is waving in the longitudinal direction, when the free end is bent or bent, the contact portion 33 is linearized in the longitudinal direction. It becomes flat, and a sufficiently long nip width can be secured together with shape stabilization by work hardening.

The greater the thickness of the thin metal spring 42 and the greater the bite amount d1, the higher the contact pressure against the developing roller 16 and the greater the control amount of the toner 24. on the other hand,
Since the load on the toner 24 increases, the toner 24
Adhesion is promoted, and the durability performance is hindered.

However, in the non-magnetic developing device 10 according to the present invention, since the second control member 34 of the rubber elastic body 50 disposed downstream has the function of actually forming the thin toner layer, the thin metal plate is formed. By setting the thickness of the first regulating member 30 of the spring 42 to 0.1 to 0.3 mm and the bite amount d1 to about 1 to 3 mm, the range of the amount of bending can be adjusted to the fatigue strength of the elastic member according to the JIS standard. 33kgf / mm ² , 10 ⁸
It can be set to be less than times. Thereby, it is possible to prevent the crimping force from lowering the pressing force and gradually deteriorating the image quality, and to ensure long-term use.

The material of the thin metal spring 42 is preferably stainless steel, which is a corrosion-resistant material having a high spring constant, a low coefficient of friction, and good workability. However, a zinc steel plate or a spring steel material may be used. If necessary, a high surface release treatment using a fluorine resin or the like can be performed.

Next, the second regulating member 34 made of the rubber elastic body 50 will be described. 2mm thick rubber elastic body 50
The urethane elastomer is cut into a predetermined strip shape, and is fixed to a holder 52 formed of a thermosetting hard resin material using a hot-met material or a double-sided tape (not shown). The non-magnetic developing device 1 has a depth d2 of 2 mm in the direction of the center C of 2 mm.
0 Assemble in the body. Reference numeral 58 in FIG.
4 is a screw for fixing the holder 52 to the main body of the non-magnetic developing device 10. Numeral 54 is a spacer for adjusting the bite amount d2.

The rubber elastic body 5 constituting the regulating member 34
The harder the hardness of 0 and the greater the thickness, the more the thin layer and the triboelectric charging function are improved. However, similarly to the first restricting member 30, the load on the toner 24 is increased, which hinders the durability performance. For this reason, the rubber hardness is 50 to 70 degrees, preferably 30 to 90 degrees according to the JIS A hardness meter, and the thickness is 1 to 3 mm.

Further, the amount of bite d into the developing roller 16
With respect to 2, the function of forming a thin layer and the triboelectric charging function are improved as the size increases, but the permanent deformation of the rubber elastic body 50 is promoted and hinders the durability performance.
3 mm. The properties required for the material of the rubber elastic body 50 include the releasability, abrasion resistance, and
It is necessary to apply a uniform constant amount of charge to the toner 24.

A typical material that satisfies these requirements is urethane elastomer. As a material having good releasability, a rubber-free ethylene-propylene trimer (EPDM) containing no silicone rubber or a plasticizer is used. Is preferred. Since the second restricting member 34 only levels the toner 24 to a single layer, it does not require a pressing force enough to cause abrasion during the service life.

According to the experience so far, the regulating member 34 of the rubber elastic body 50 is advantageous for forming a thin layer of the toner 24, but is disadvantageous for fixing the toner 24, so that several thousand sheets On paper, the image quality is hindered by the adhesion of the toner 24. On the other hand, the regulating member 30 of a thin metal spring is advantageous for fixing the toner 24, but disadvantageous for forming a thin layer because the elasticity cannot be maintained unless the thin plate is formed.

Therefore, as the regulating member for controlling the amount of the toner 24, a metal member which is poor in compatibility with the toner 24 and has little adhesion since the toner 24 is conveyed in a large amount is suitable. On the other hand, as the regulating member 34 for forming a thin layer of the toner 24, a rubber elastic body 50 having higher elasticity is used to level the thin layer of the toner 24 in order to maintain the close contact with the developing roller 16. It is suitable for. Further, since the longitudinal side ridge line 36 is sequentially contacted in the rotation direction of the developing roller 16, the occurrence of abrasion which is related to the deterioration of the image quality during the service life is not recognized.

As a conventional technique, as described above, either one of the first and second regulating members 30, 34 is used alone. Therefore, a comparative example in which the regulating members of the present invention are individually used will be described.

[Comparative Example 1] A regulating member 30 of a thin metal spring
When used alone, the regulating member 30 is attached to the developing roller 16 by applying a uniform thin layer of the toner 24 and having a uniform triboelectric charging function by applying the longitudinal side surface of the thin metal spring 42 to the abdomen. Since the toner 24 needs to be bitten excessively and the toner 24 sticks to deteriorate the durability performance, the replacement is required several to ten or more times for the service life.

Further, since a more uniform thinning is required, strict linearity is required for the side flank portion, which causes a reduction in manufacturing process capability, a large load in appearance and dimensional inspection, and in some cases, It is also necessary to perform a surface treatment for uniform charging, leading to an increase in cost.

[Comparative Example 2] Regulation member 3 of rubber elastic body 50
When the toner 4 is used alone, the amount of toner 24 that has been excessively conveyed is controlled by abutting the longitudinal ridge 54 of the rubber elastic body 50, and a uniform thin layer is formed and a uniform triboelectric charging function is achieved. The toner 24 having a large particle diameter slips through and the toner 2 having a small charge amount
4 was conveyed, and as a result, the cause of the occurrence of abnormal images such as reduced dot reproducibility and background contamination.

In general, the components of the toner 24 have good compatibility with the rubber elastic body 50, so that the toner 24 easily adheres to the regulating member 34, thereby lowering the durability. Had to be replaced several times.

[0035]

As is apparent from the above description, according to the non-magnetic developing device of the present invention, the functions of controlling the amount of toner and forming the thin layer are separated into two regulating members, so that the uniform thin layer can be formed. In addition, uniform triboelectric charging is easy, dot reproducibility is good, and a high-quality image state without background smear can be maintained.

Further, the load on the toner and the developing roller can be reduced, and the deterioration of the durability performance due to creep, abrasion and sticking of the toner can be prevented, so that a longer life and less maintenance can be achieved. In addition, the requirements for the required precision and appearance quality of the parts are reduced, the capability of the manufacturing process can be improved, the efficiency of the inspection can be increased, and the cost of the parts can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of a non-magnetic developing device according to the present invention.

FIG. 2 is an explanatory diagram showing an enlarged view of a portion of a regulating member in the non-magnetic developing device according to the present invention.

FIG. 3 is a schematic plan view showing a first regulating member in the non-magnetic developing device according to the present invention.

FIG. 4 is a schematic plan view showing a second regulating member in the non-magnetic developing device according to the present invention.

DESCRIPTION OF SYMBOLS 10 Non-magnetic developing device 12 Photoreceptor drum 14 Toner container 16 Developing roller 18 Replenishment roller 24 Toner 28 Toner stirring member 30 First regulating member 34 Second regulating member 36 Longitudinal ridge line (of rubber elastic body) 40 Intermediate bias voltage 42 Thin metal spring 50 Rubber elastic

Claims (3)

[Claims] A developing roller disposed in contact with or close to the image carrier for visualizing the electrostatic latent image on the image carrier into a toner image; A toner thin layer forming means for forming a layer, wherein the toner thin layer forming means contacts a developing metal roller with a thin metal spring to regulate the amount of toner carried on the developing roller. First restricting means, and second restricting means for contacting the rubber elastic body at a downstream position in the rotation direction from the contact position of the metal thin plate spring to reduce the thickness of the carried toner. A developing device. 2. The thin metal spring has a thickness of 0.05 m.
2. The developing device according to claim 1, wherein the length of the developing roller is not less than m and not more than 0.5 mm, and one side surface in a longitudinal direction is in contact with the developing roller over the entire length of the developing roller. 3. The rubber elastic body has a thickness of 0.5 mm or more and 5.0 mm or less and a rubber hardness of 30 degrees or more and 9 degrees or more.
2. The developing device according to claim 1, wherein the developing device is at an angle of 0 degree or less (JIS A) and abuts on one edge of the developing roller in the longitudinal direction to contact the developing roller over its entire length.