JPH0527581A - Developing device - Google Patents

Abstract

PURPOSE:To obtain images having high image quality by subjecting the surface of a developer carrying member to a spherical blasting treatment, then coating the surface with a hard surface treated layer, thereby stabilizing the transporting property of a developer, providing durability, lessening the change in image density with lapse of time, reducing the layer thickness of the developer and stably and thinly maintaining the developer layer. CONSTITUTION:The surface of the developer carrying member (developing sleeve) 2 is subjected to the spherical blasting treatment and thereafter, the surface thereof is coated with the hard surface treated layer 21. The surface of the developing sleeve 2 is first coated with the hard rugged surface which is smoother than the sand blasted surface. Namely, work hardening is generated in the surface of the developing sleeve 2 by the spherical blasting treatment and this surface is eventually coated with the hard surface having the fine ruggedness. The surface is then eventually coated with, for example, a hard anodized aluminum treated layer which is the hard surface treated layer if the material is an aluminum alloy and with, for example, a hard nickel chrome plating layer if the material is brass.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device applied to the development of a latent image on an image carrier used in an electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus for developing a latent image formed on an image bearing member such as a photosensitive member by a contact or non-contact developing method using a one-component or two-component developer, In order to obtain a good image, it is necessary that the layer thickness of the developer on the developing sleeve (hereinafter referred to as the developing sleeve), which is the developer carrier, be thin and uniform. As shown in FIG. 7, the developing sleeve faces the image carrier 1, which is a photoconductor, with a slight gap. Then, as shown in FIGS. 7A, 7B, and 7C, a thin layer forming body (hereinafter referred to as a thin layer forming body), which is a developer amount regulating body for regulating the layer thickness on the developing sleeve, is pressed. is doing.

FIG. 7A shows a thin layer forming body made of a magnetic material.
In the figure, a method of pressing 31 against the developing sleeve 2 by the magnetic force of a magnet body provided in the developing sleeve 2 is shown.

FIG. 7B shows a system in which the pressing force of the elastic member 4 is applied to the thin layer forming body 31 in addition to the system of FIG. 7A.

FIG. 7C shows a system in which the thin layer forming body 31 is made of a rubber plate or a metal spring plate and is pressed against the developing sleeve 2 by its elasticity.

Since the thin layer forming body is pressed against the developing sleeve in this way, the surface of the developing sleeve rubs against the thin layer forming body, and the two are abraded.

The surface of the developing sleeve 2 is formed with fine irregularities by an irregular blasting process such as a sand blasting process in order to improve the carrying property of the developer, which is a carrying property. As is well known, the sandblast treatment is to spray irregularly shaped sand particles at high speed to make fine irregularities on the metal surface. The developing sleeve is usually made of a non-magnetic, relatively soft metallic material such as aluminum alloy or brass. Therefore, the surface of the developing sleeve 2 that has been sandblasted is rough and fluffy as shown in FIG.

Since the surface of the developing sleeve thus sandblasted is rough and has a fluffy surface state, the transportability of the developer is improved, but on the other hand, the following problems occur. As a result, spherical blasting has come to be considered.

This spherical blasting process is a process using small still balls or glass beads instead of irregularly shaped sand particles. The surface of the developing sleeve 2 by this treatment is
When this is magnified and seen, the surface is uneven as shown in FIG. 9, but it is much smoother than the sandblasted surface. Moreover, since a small still ball or glass ball is made to collide with the surface of the developing sleeve at a high speed, the effect of work-hardening the surface of the developing sleeve is greater than that of sandblasting in which irregular-shaped sand particles having sharp edges are collided.

Then, the development sleeve subjected to the sand blast treatment and the development sleeve subjected to the spherical blast treatment,
The graph shown in FIG. 10 shows how the developer transport amount changes with the use time of the developing sleeve. In this graph, B shows the case of sandblasting, and A shows the case of spherical blasting.

As can be easily seen from this graph, in the case of sandblasting with irregular particles, the amount of developer conveyed is large at first, but the amount of developer conveyed decreases rapidly with the lapse of use time. Is shown.

On the other hand, in the case of the spherical blast treatment, it is shown that the developer carrying amount is not large from the beginning, but the developer carrying amount does not change much even after the use time elapses.

The developing sleeve is usually made of a non-magnetic and relatively soft metallic material such as aluminum alloy or brass as described above. Therefore, in order to improve the corrosion resistance and the surface hardness, the surface is subjected to a surface treatment such as a hard alumite treatment in the case of an aluminum alloy and a hard nickel / chrome plating treatment in the case of a brass.

[0014]

The surface of the developing sleeve which has been sandblasted as described above has a rough and fluffy surface state as shown in FIG. 8, and the thin layer forming body is pressed against this surface. As a result, the surface of the developing sleeve is rapidly abraded. The sandblast treatment on the surface of the developing sleeve is originally performed to improve the transportability of the developer. Therefore, the change in the amount of developer conveyed is large when the developing sleeve is new and when it is used a little, and as described above, the situation is as shown by the curve in FIG. 10B. This change in the transport amount of the developer naturally results in a high image density and poor image quality because the developer layer on the surface of the developing sleeve becomes thick when the transport amount is large. Also,
When the transport amount of the developer is small, the layer thickness of the developer layer on the surface of the developing sleeve becomes thin, so that the image quality tends to be improved, but the image density becomes small.

Further, if the pressing force of the thin layer forming body against the developing sleeve is weakened to reduce abrasion, the change with time can be reduced. However, since the pressing force of the thin layer forming body against the developing sleeve becomes weaker, the developer layer of the developing sleeve becomes thicker and the thickness of the developer layer becomes unstable and non-uniform, resulting in deterioration of image quality.

The present invention has been made to solve the above problems. That is, the developer transportability of the developing sleeve is stabilized to provide durability, the temporal change of the image density is reduced, the developer layer thickness of the developing sleeve is made thin, and it can be stably kept thin. It is an object of the present invention to provide a developing device capable of obtaining a high quality image.

[0017]

SUMMARY OF THE INVENTION The above object is to provide a developer carrier having rigidity for carrying a developer on the surface thereof for developing a latent image formed on the image carrier, and the developer carrier. In a developing device provided with a developer amount regulating body that presses against the body and regulates the amount of the developer carried on the developer carrying body, after the surface of the developer carrying body is subjected to spherical blast treatment, It is achieved by a developing device characterized by being covered with a hard surface treatment layer.

Further, the above-mentioned object is a developing apparatus characterized in that the surface of the developer carrying member is spherically blasted, then covered with a hard surface treatment layer, and further spherically blasted.

Further, the developing device is characterized in that the surface of the developer carrying member is subjected to an amorphous blast treatment, then covered with a hard surface treatment layer, and further subjected to a spherical blast treatment.

Further, it is achieved by a developing device characterized in that the surface of the developer carrying member is covered with a hard surface treatment layer and then spherical blast treatment is carried out.

The above object is also achieved by a developing device characterized in that the hardness of the hard surface treatment layer is higher than the surface hardness of the developer carrying member.

Further, the above object is achieved by a developing device characterized in that the developer amount regulating body is a magnetic body and is pressed against the developer carrying body by a magnetic force.

[0023]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 5 is a sectional view of a developing device using a one-component developer.

Inside the housing 51 of the developing device 50, the developing sleeve 2 as a developer carrying member and the magnet roller 5 are provided.
3, a vibrating plate 54 for preventing development toner coagulation, a toner remaining amount detecting means 55, and the like are provided. The developing sleeve 2 is a non-magnetic cylindrical body that is driven and rotated counterclockwise in the drawing, and has a magnet roller 53 fixed therein so as not to rotate, and a part of the longitudinal surface of the developing sleeve 2 is It is exposed from the opening of the housing 51, and is arranged in parallel with and in close proximity to the image carrier 1.

A toner replenishing container 56 is removably attached to the upper portion of the lid member 58 that closes the upper opening of the housing 51.

In the inner concave portion of the lid member 58, a thin layer forming body 31 such as a stainless steel rod having rigidity and magnetism that regulates the layer thickness of the developer, and a holder 61 holding the thin layer forming body 31. And a developer amount regulating means including an elastic member 4 and the like for pressing the thin layer forming body 31.

The gap between the developing sleeve 2 and the image bearing member (photosensitive drum) 1 is provided coaxially with the axial end of the developing sleeve 2 and rollers (not shown) are provided at both ends of the peripheral surface of the image bearing member 1. By abutting the outside of the image forming area in the vicinity, it is always held at a constant gap.

Here, 59 is a developing region formed in the gap between the image carrier 1 and the developing sleeve 2, and 65 is an AC bias power source in which a DC voltage and an AC voltage are superposed.

The new toner replenished from the toner replenishing container 56 is contained in the housing 51, is agitated by the vibration of the vibrating plate 54, and is layered on the peripheral surface of the developing sleeve 2 which is driven and rotated counterclockwise in the drawing. The thin layer forming body 31 passes through the pressing position of the thin layer forming body 31 to form a predetermined thin layer.

FIG. 6 is a vertical sectional view of the developer amount regulating means. A plurality of elastic members 4 are attached to a part of the inner wall of the groove 51A of the lid member 58. The thin layer forming body 31 is dropped into the concave portion formed by the elastic member 4 and the groove portion 51A. Then, the tip portions of the protrusions 61A of the holder 61 are loosely fitted and inserted into the center holes 60A at both ends of the thin layer forming body 31.

The holder 61 is fixed to both side surfaces of the lid member 58 with machine screws. In this way, the thin layer forming body 31
Does not fall off or come off the holder 61. Of course, the fitting state of the projection 61A and the center hole 60A is loose so that there is a margin such that it does not come off.

The magnetic thin layer forming body 31 has a magnetism opposite to the magnetism of the magnet roller 53 which faces it, and the attraction force of the magnetism and the elastic force of the elastic member 4 cooperate to the developing sleeve 2. The pressing force is obtained.
The developer D carried on the developing sleeve 2 lifts the thin layer forming body 31 against the pressing force of the magnetic thin layer forming body 31 and the elastic member 4, and passes through the gap formed at the pressure contact position. By doing so, a uniform developer layer set thickness can be obtained. Then, in correspondence with the set gap in the developing area between the image carrier 1 and the developing sleeve 2, optimum developing can be performed.

After the development is completed, the residual developer D on the developing sleeve 2 is returned to the housing 51 of the developing device 50 and is sprayed again on the developing sleeve 2 to continuously develop.

Next, the core of the present invention will be described with reference to FIGS. 1 to 4.

First, FIG. 1 shows, as a first embodiment, an enlarged view of a state in which the surface of the developing sleeve 2 is spherically blasted and then covered with a hard surface treatment layer 21. When such a treatment is performed, the surface of the developing sleeve 2 is first covered with a surface having a hard and uneven surface which is smoother than the surface of the sandblast treatment. That is, since the surface of the developing sleeve 2 is spherically blasted, work hardening occurs and the surface is covered with a hard surface having fine irregularities. Then, when the material is an aluminum alloy, the surface is covered with a hard surface-treated layer, for example, a hard alumite treatment layer, and when the material is brass, for example, a hard nickel chrome plating layer.

FIG. 2 shows, as a second embodiment, an enlarged view of a state where the hard surface treatment layer 21 of FIG. 1 is further subjected to spherical blast treatment. That is, by further performing the spherical blasting treatment on the hard surface treatment layer 21, the surface of the hard surface treatment layer 21 is further processed into an uneven surface, and is covered with the hard surface that has been further work hardened.

As a third embodiment, FIG. 3 is an enlarged view of a state in which the surface of the developing sleeve 2 is sandblasted and then covered with a hard surface treatment layer 21, and the treatment layer is further spherically blasted. Is shown. Therefore, the completed surface state is very similar to the state shown in FIG. 2 and the surface hardness is also about the same, but since the surface of the developing sleeve 2 is first sandblasted, compared to FIG. The finished surface state is slightly uneven.

FIG. 4 shows, as a fourth embodiment, an enlarged view of a state in which the surface of the developing sleeve 2 is covered with a hard surface treatment layer 21 and a spherical blast treatment is performed on it. Therefore, the surface of the hard surface treatment layer 21 is covered with the hard surface by work hardening together with the unevenness due to the spherical blast treatment.

The developing sleeves shown in FIGS. 1 to 4 are summarized as follows.

By the spherical blasting treatment, the surface of the developing sleeve becomes a relatively smooth uneven surface, which is not a rough fluffy surface as in the sandblasting treatment, and the surface is subjected to a hard surface treatment, so that abrasion resistance is caused. When the spherical blast treatment is performed on this surface, the spherical blast treatment is used to process the surface further into an uneven surface, and the surface of the hard surface treatment layer is further processed and hardened to increase abrasion resistance and to convey the developer. The change over time in the amount was reduced and the durability was improved. Further, due to the surface condition of the developing sleeve, a thin layer of the developer can be formed, so that the thin layer forming body can be pressed against the developing sleeve with a weak force. Due to the combined effect of both of them, the developing sleeve has much more excellent durability than the conventional one, and stable thin layer formation can be performed, so that it is possible to form a high quality image with little change with time. ..

Further, according to the present invention, the surface of the developing sleeve is free of sharp protrusions as in the sandblasting process. Therefore, even if an AC bias voltage is applied to the developing sleeve in order to improve developability, the AC bias voltage leaks. Since this is less likely to occur, there is an advantage that the developability is improved.

[0043]

According to the present invention, the developer carrying property of the developing sleeve is stabilized to provide durability, the change of the image density with time is reduced, and the developing sleeve layer thickness is made thin and stable. Thus, a developing device is provided which is capable of holding a thin image and is capable of obtaining a high quality image.

[Brief description of drawings]

FIG. 1 is an enlarged view of the surface of a developer carrying member (developing sleeve) according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of the surface of a developer carrying member (developing sleeve) according to a second embodiment of the present invention.

FIG. 3 is an enlarged view of the surface of a developer carrying member (developing sleeve) according to a third embodiment of the present invention.

FIG. 4 is an enlarged view of the surface of a developer carrying member (developing sleeve) according to a fourth embodiment of the present invention.

FIG. 5 is an overall configuration diagram of a developing device based on the present invention.

FIG. 6 is a longitudinal sectional view of the vicinity of a developer amount regulating body (thin layer forming body) of a developing device according to the present invention.

FIG. 7A is a diagram of a main part of a conventional developing device, and FIG. 7A is a diagram showing a state in which a developer amount regulating body (thin layer forming body) is pressed against a developing sleeve by a magnetic force. FIG. 9B is a diagram showing a situation in which the pressing force of the elastic member is further applied to FIG.
(C) is a figure in case a developer amount regulation body (thin layer formation body) is a tabular elastic material.

FIG. 8 is an enlarged view of the surface of a developer carrying member (developing sleeve) that has been sandblasted.

FIG. 9 is an enlarged view of the surface of a developer carrying member (developing sleeve) that has been spherically blasted.

FIG. 10 is a graph showing changes over time in the amount of developer conveyed in spherical blasting and sandblasting.

[Explanation of symbols] 1 Image carrier 2 Developer support (development sleeve) 21 Hard surface treatment layer 31 Developer amount regulator (thin layer former) 50 Development device

Claims (6)

[Claims] 1. A developer carrier having rigidity for carrying a developer on a surface for developing a latent image formed on an image carrier, and the developer being pressed against the developer carrier. In a developing device provided with a developer amount regulating body that regulates the amount of the developer carried on a carrier, the surface of the developer carrier is covered with a hard surface treatment layer after spherical blasting. Developing device. 2. The developing device according to claim 1, wherein the surface of the developer carrying member is spherically blasted, then covered with a hard surface treatment layer, and further spherically blasted. 3. The developing device according to claim 1, wherein the surface of the developer carrying member is subjected to an amorphous blast treatment, then covered with a hard surface treatment layer, and further subjected to a spherical blast treatment. 4. The developing device according to claim 1, wherein the surface of the developer carrier is covered with a hard surface treatment layer and then spherical blast treatment is performed. 5. The developing device according to claim 1, wherein the hardness of the hard surface treatment layer is higher than the surface hardness of the developer carrier. 6. The developing device according to claim 1, wherein the developer amount regulating body is a magnetic body and is pressed against the developer carrying body by a magnetic force.