JPH0540399A - Developing device - Google Patents

Abstract

PURPOSE:To obtain images having high image quality by sufficiently electrifying a developer to prevent the degradation in image density and the deterioration in the performance of the developer, thereby allowing the formation of a uniform thin layer of the developer on a developing sleeve even if the pressing force of a thin layer forming body pressed to the developing sleeve is not increased. CONSTITUTION:The thin layer forming body 31 is constituted by providing parallel grooves on an end face, winding a wire around a developing sleeve, providing spiral grooves or parallel grooves parallel with the transporting direction of the developer on the developing sleeve or, in the case of a spring sheet material, by providing the parallel grooves parallel with the transporting direction of the developer on the pressing surface to the developing sleeve. This forming body is brought into pressurized contact with the developing sleeve 2 by prescribed pressing force. The pitch of the grooves or the depth of the grooves and the size of the wire are set at nearly 0.1 to 20 times, more preferably 1.5 to 20 times the grain size of the developer.

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 developer carrying member (developing sleeve) is thin and uniform. As shown in FIG. 10, the developing sleeve 2 faces the image carrier 1, which is a photoconductor, with a slight gap. Then, as shown in (a), (b), and (c) of FIG.
A developer amount regulator 31 that regulates the layer thickness of the developing sleeve.
(Thin layer forming body) is pressed.

FIG. 10A shows a system in which a thin layer forming body 31 of a round bar made of a magnetic material is pressed against the developing sleeve 2 by the magnetic force of a magnet provided inside the developing sleeve 2.

FIG. 10 (b) 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. 10 (a).

FIG. 10C shows a system in which the thin layer forming body 31 is made of a spring plate material such as a rubber plate or a metal spring plate, and is pressed against the developing sleeve 2 by its elasticity.

In order to improve the carrying property of the developer D, which is the transportability of the developer D, the surface of the developing sleeve 2 is formed with fine irregularities by an irregular blasting process such as a sand blasting process. As is well known, the sandblast treatment is to spray irregularly shaped sand particles at high speed to form fine irregularities on the metal surface. By making the surface of the developing sleeve 2 in such a surface state and by the electric force and magnetic force described later, the developer D is attached to the surface of the developing sleeve 2 and conveyed, and is formed in a narrow gap portion facing the image carrier 1. Image carrier 1 in the developed area
The latent image formed on is developed.

In order to develop the latent image formed on the image carrier 1, it is necessary to charge the developer D. To this end, in the case of a two-component developer, the developer D is stirred by a developer stirring device (not shown) provided in the developer tank 5, and the developer is charged by friction between the developers. It is like this. In order to obtain a good image on the developing sleeve 2, the thin layer forming body 31 is pressed as described above so that the layer thickness of the developer is thin and uniform, but in the case of a one-component developer, it is thin. The developer is charged by friction when the developer passes between the layer forming body 31 and the developing sleeve 2.

[0008]

As described above, in order to make the developer layer on the surface of the developing sleeve thin and uniform, and in the case of a one-component developer, the thin layer forming body is applied to the developing sleeve in order to charge the developer. Although pressed, the thin layer forming body was strongly pressed against the developing sleeve in order to obtain a sufficient charge amount of the developer. The developing sleeve is usually made of a non-magnetic, relatively soft metallic material such as aluminum alloy or brass. As described above, the surface of the developing sleeve is subjected to a blasting process such as a sandblasting process in order to improve the transportability of the developer, and the surface has fine irregularities. Therefore, if the thin layer forming body is strongly pressed against the surface of the developing sleeve, the surface of the developing sleeve is subject to abrasion. For this reason, the developer transport property on the surface of the developing sleeve is deteriorated, the developer transport amount is reduced, and the image density is reduced.

Further, since the thin layer forming body is strongly pressed against the developing sleeve as described above, the gap between the developing sleeve and the thin layer forming body becomes very small, and the developer passing through this gap is not the developer. Since it is a powder, the surface of each powder will be damaged, and the performance of the developer as a result of, for example, the additive applied to improve the fluidity of the surface of the powder will come off. There was a situation where it deteriorated.

The present invention has been made to solve the above problems. That is, the developer is sufficiently charged without increasing the pressing force of the thin layer forming body pressed against the developing sleeve, thus reducing the abrasion of the developing sleeve,
This prevents a decrease in image density due to a decrease in the amount of developer conveyed, and further, the strong pressing force of the thin layer forming body prevents the performance of the developer due to the forced passage of the developer between the thin layer forming body and the developing sleeve. It is an object of the present invention to provide a developing device which is capable of preventing and forming a uniform thin layer of the developer on the developing sleeve to obtain a high quality image by these effects.

[0011]

SUMMARY OF THE INVENTION The above-mentioned object is to develop a latent image formed on an image bearing member, a developer bearing member carrying a developer on the surface, and a pressing force applied to the developer bearing member. Then, in a developing device provided with a developer amount regulating body for regulating the amount of the developer carried on the developer carrying body, an end surface of the developer amount regulating body which is in pressure contact with the developer carrying body. The developing device is characterized in that a parallel groove is provided in a direction substantially parallel to the direction in which the developer is conveyed, and further, the pitch of the parallel groove provided on the end face of the developer amount regulating body is The developing device is characterized in that the particle diameter of the developer is approximately 0.1 to 20 times, and the depth of the groove is approximately 0.1 to 20 times the particle diameter of the developer.

Further, the above-mentioned object is a developing device characterized in that the developer amount regulating member is made of a rod having a circular cross section, and a wire is wound on the surface so as to have the same diameter. Further, the thickness of the wire wound around the surface of the developer amount regulating member is approximately 0.1 to 20 times the particle diameter of the developer, which is achieved by the developing device.

Further, the above-mentioned object is that the developer amount regulating member is made of a rod having a circular cross section, and the surface thereof has a spiral groove having a pitch of about 0.1 to 20 times the particle diameter of the developer, or a developing member. The particle size of the developer is approximately 0.1 in the direction parallel to the conveying direction of the developer.
This is achieved by a developing device characterized in that parallel grooves having a pitch of 20 to 20 times are provided.

In the case where the developer amount regulating member is a rotatable developer amount regulating member, it is achieved by a developing device characterized in that it is driven to rotate by the developer carrying member or driven and rotated by power. ..

Further, for the above-mentioned purpose, the developer amount regulating body is made of a plate material having a spring property and is capable of pressing the developer carrying body. This is achieved by a developing device characterized in that parallel grooves having a pitch of approximately 0.1 to 20 times the diameter are provided in a direction substantially parallel to the direction in which the developer is conveyed.

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.

[0017]

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

FIG. 8 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. 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 close 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 developer amount regulating body (thin layer forming body) 31 such as a stainless steel rod having rigidity and magnetism for regulating the layer thickness of the developer, and the thin layer forming A holder 61 for holding the body 31 and a developer amount regulating means including an elastic member 4 for pressing the thin layer forming body 31 are provided.

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 area formed in a 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 accommodated 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 is conveyed by being adhered to the sheet, and passes through the pressing position of the thin layer forming body 31 to form a predetermined thin layer.

FIG. 9 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 ends 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 sides 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, and there is a margin to prevent it from coming off.

The magnetic thin layer forming body 31 has a magnetism opposite to the magnetism of the magnet roller 53 which faces the magnetism. 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, the developer D remaining on the developing sleeve 2 is returned to the inside of the housing 51 of the developing device 50 and scattered again on the developing sleeve 2 to continuously develop it.

Next, the core of the present invention will be described with reference to FIGS. 1 to 7.

FIG. 1 shows the first embodiment of the present invention. The thin layer forming body 31 which is a developer amount regulating body is made of a plate material having a certain thickness, and is a thin layer which comes into pressure contact with the developing sleeve 2. As shown in the figure, trapezoidal grooves having a depth dp are provided on the end surface of the forming body 31 at intervals of a pitch P in a direction substantially parallel to the conveying direction of the multiplicity of developers, and are in pressure contact with the developing sleeve 2. Is shown.

FIG. 5 is an enlarged view of a state in which the thin layer forming body 31 having such a shape is pressed against the developing sleeve 2.

FIG. 5 (a) shows a case where the pressing force of the thin layer forming body 31 against the developing sleeve 2 is relatively weak, and a small amount of developer enters between the thin layer forming body 31 and the developing sleeve 2. , A gap c is formed and the developing sleeve 2 is pressed. In such a state, since the pressing force is small, the developer as powder is not so much damaged, that is, deteriorated. In the trapezoidal gap DC portion shown, the developer passes while being sandwiched between the thin layer forming body 31 and the developing sleeve 2. Therefore, the developer passes without being damaged, that is, deteriorated, and immediately after passing, the developer spreads on the developing sleeve 2 in a flow similar to a fluid, even if it is a powder, and spreads on the developing sleeve 2 to form a uniform thin layer. Then, the latent image is developed by being transferred to the developing area.

FIG. 5B shows a case where the pressing force of the thin layer forming body 31 against the developing sleeve 2 is strong, and the thin layer forming body 31 is in contact with and pressing the developing sleeve 2. In such a state, the developer hardly enters between the trapezoidal groove tip of the thin layer forming body 31 and the developing sleeve 2, and only the trapezoidal gap DC portion shown in FIG. ), So that the developer passes through without being solidified and damaged, that is, without being deteriorated. Immediately after passing, the developer spreads on the developing sleeve 2 to form a uniform thin layer. It is the same as in the case of FIG. 5 (a) described above that the latent image is developed by being transferred to the developing area as a developer layer thickness.

In this way, the case of FIG.
Also in the case of (b), the developer passes between the thin layer forming body 31 and the developing sleeve 2, but at this time, the thin layer forming body 31.
Since an inclined surface is also added to the pressing contact surface with the developing sleeve 2, the surface area is greatly increased. Such a large surface area means that the contact area with the developer increases, so that the developer at this point is more rubbed between the thin layer forming body 31 and the developing sleeve 2. As a result, it is more charged.

As described above, by providing a trapezoidal cutout groove on the pressing contact surface of the thin layer forming body to the developing sleeve in a direction substantially parallel to the conveying direction of a large number of developers, the developer is transferred onto the developing sleeve. It facilitates formation of a uniform thin layer, prevents deterioration of the developer, and charges the developer more.

The values of the depth dp and the pitch P of the trapezoidal grooves provided in the thin layer forming body 31 are determined by the performance of the developer and the thinness in order to obtain the required layer thickness of the developer layer on the developing sleeve. It will change depending on the pressing force of the layer forming body against the developing sleeve and other developing conditions.

The values of the groove depth dp and the pitch P are approximately 0.1 to 20 times the particle diameter of the developer, and more preferably the value.
Good results were obtained experimentally when a value of 1.5 to 20 times was adopted.

FIG. 2 is a second embodiment of the present invention and shows that the thin layer forming body which is the developer amount regulating body is a round bar material in which a wire material is tightly wound. ..

As shown in the figure, the thin layer forming body 31 is formed by tightly winding a wire rod 312 of a direct line d on a round bar 311, that is, at a pitch P = d. Thin layer forming body having such a structure
FIG. 6 is an enlarged view of the state where 31 is pressed against the developing sleeve 2.

FIG. 6A shows a case where the pressing force of the thin layer forming body 31 against the developing sleeve 2 is comparatively weak, and a slight amount of development occurs between the wire 312 of the thin layer forming body 31 and the developing sleeve 2. The state is shown in which the agent has entered and a gap c has been formed to press the developing sleeve 2. And in the present invention, the thin layer forming body 31
Is driven to rotate by a frictional force with the developing sleeve 2 or driven to rotate by another power. In such a state, the developer enters between the wire 312 and the developing sleeve 2 to form a gap c, but the pressing force is small, so that the developer as a powder does not suffer such damage, that is, deterioration. In the triangular gap TC portion shown in the figure, the wire rod 312 is wound around the round bar member 311.
The surface of 312 has a spiral shape, and since the thin layer forming body 31 also rotates, the developer also receives a force between the wire 312 and the developing sleeve 2 in a direction parallel to the rotation axis of the thin layer forming body 31, so that the developer hardens. Without passing, the wire 312 passes between the wire 312 and the developing sleeve 2. Therefore, the developer passes without being damaged, that is, deteriorated, and immediately after passing, the developer spreads on the developing sleeve 2 in a flow similar to a fluid, even if it is a powder, and spreads on the developing sleeve 2 to form a uniform thin layer. Then, the latent image is developed by being transferred to the developing area.

FIG. 6B shows the case where the pressing force of the thin layer forming body 31 against the developing sleeve 2 is strong, and the wire 312 of the thin layer forming body 31 is in contact with and pressing the developing sleeve 2. ing. In such a state, the developer hardly enters between the wire rod 312 and the developing sleeve 2, and the developer passes only the triangular gap TC portion shown in the same manner as in the case of FIG. 6A, Therefore, the developer passes through without hardening, that is, without deterioration, that is, without deterioration, and immediately after passing, the developer spreads on the developing sleeve 2 to form a uniform thin layer having a predetermined developer layer thickness and a developing area. Transferring to and developing the latent image is similar to the case of FIG. 6A described above.

In this way, also in the case of FIG.
Also in the case of (b), the developer passes between the thin layer forming body 31 and the developing sleeve 2, but at this time, the thin layer forming body 31.
Since the wire rod 312 is closely wound on the surface of, the surface area is increased by about 1.6 times. Such a large surface area means an increased contact area with the developer, so that the developer at this point is more rubbed between the thin layer forming body 31 and the developing sleeve 2. As a result, it is more charged.

By thus forming the thin layer forming body in a structure in which the wire is wound around the round bar, the uniform thin layer of the developer can be easily formed on the developing sleeve, and the deterioration of the developer can be prevented. It was supposed to charge the developer more.

The layer thickness of the developer on the developing sleeve 2 can be controlled also by the thickness d and the pitch P of the wire rod 312 wound around the round rod 311 of the thin layer forming body 31.

FIG. 7A shows a wire rod 312 having a thickness d and a pitch P.
1> d shows the state of being wound around the round bar 311. In such a state, the triangular clearance TC1 is
Since it can be formed between the wire rod 312 and the round bar 311, the amount of the developer passing between the wire 312 and the developing sleeve 2 is increased, and the layer thickness on the developing sleeve 2 is increased.

FIG. 7B shows a state in which the wire rod 312 having the thickness d1 <d is wound around the round bar 311 at the pitch P2 = d1. In such a state, the triangular clearance TC2
Is smaller than the triangular clearance TC in FIG. 6, the amount of developer passing between the wire 312 and the developing sleeve 2 is reduced, and the layer thickness on the developing sleeve 2 is thin.

As described above, the layer thickness of the developer layer on the developing sleeve 2 can be controlled by the thickness d and the pitch P of the wire rod 312 wound around the round rod 311 of the thin layer forming body 31. The value of the pitch P is basically determined by the thickness d of the wire 312. Ie wire rod 312
If the thickness d is small, the pitch P is necessarily small, and if the thickness d is large, the pitch P is also large. Further, the value of the pitch P starts from dense winding P = d and becomes spaced P> d to obtain a necessary layer thickness of the developer layer on the developing sleeve. It will change depending on the pressing force of the layer forming body against the developing sleeve and other developing conditions.

The thickness d of the wire 312 is approximately 0.1 to 20 times the particle diameter of the developer, and more preferably 1.5 to 20 times.
Good results were obtained experimentally when 20 times the value was adopted.

FIG. 3 shows a third embodiment of the present invention in which a thin layer forming body which is a developer amount regulating body is a round bar material provided with spiral grooves having a pitch P.

Since the operation and effect in this case are almost the same as those shown in FIG. 1, description thereof will be omitted. Also,
Instead of the spiral groove, a parallel groove in a direction parallel to the developer conveying direction may be used.

FIG. 4 shows a fourth embodiment of the present invention, in which the thin layer forming body is made of a spring plate material such as a metal spring plate, and the pressing surface to the developing sleeve is substantially parallel to the direction in which the developer is conveyed. A parallel groove having a pitch P is provided in the direction. In this case, it is considered that the diameter of the round bar in FIG. 3 became extremely large and became close to a plane. However, although the round bar in FIG. 3 rotates, in this case it does not rotate and is fixed. However, the operation and effect thereof are almost the same as in the case of FIG.

The pitch P in the case of FIGS. 3 and 4 is as shown in FIG.
It is considered that the properties of both the thickness d and the pitch P of the wire rod 312 in the case of are included, and therefore the wire rod 312 in the case of the pitch P of FIG.
Since the same effect as the thickness d of the developer is exhibited, the pitch P is preferably set to be 0.1 to 20 times, more preferably 1.5 to 20 times the particle diameter of the developer as in the case of FIG.

[0053]

According to the present invention, the developer is sufficiently charged without increasing the pressing force of the thin layer forming body which is pressed against the developing sleeve, and therefore, the wear of the developing sleeve is reduced, thereby reducing the wear of the developing sleeve. Prevents the decrease in image density due to the reduction in the amount of developer conveyed, and the strong pressing force of the thin layer former prevents the deterioration of the performance of the developer due to the forced passage of the developer between the thin layer former and the developing sleeve. However, it is possible to form a uniform thin layer of the developer on the developing sleeve, and it is possible to provide a developing device capable of obtaining a high-quality image by these effects.

[Brief description of drawings]

FIG. 1 is an enlarged view of the vicinity of a developer amount regulating body (thin layer forming body) according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of the vicinity of a developer amount regulating body (thin layer forming body) according to a second embodiment of the present invention.

FIG. 3 is an enlarged view of the vicinity of a developer amount regulating body (thin layer forming body) according to a third embodiment of the present invention.

FIG. 4 is an enlarged view of the vicinity of a developer amount regulating body (thin layer forming body) according to a fourth embodiment of the present invention.

5A and 5B are partially enlarged views of a developer amount regulating body (thin layer forming body) of the first embodiment.

6A and 6B are partially enlarged views of a developer amount regulating body (thin layer forming body) of the second embodiment.

7A and 7B are another partially enlarged views of the developer amount regulating body (thin layer forming body) of the second embodiment.

FIG. 8 is an overall configuration diagram of a developing device based on the present invention.

FIG. 9 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. 10 is a diagram of a main part of a conventional developing device, and FIG. 10A 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. FIG. 6C is a diagram when the developer amount regulating body (thin layer forming body) is a plate-shaped elastic material.

[Explanation of symbols]

 1 image carrier 2 developer carrier (developing sleeve) 31 developer amount regulator (thin layer forming body) 311 round bar material 312 wire rod 4 elastic member 50 developing device c gap dp groove depth d, d1 thick wire rod P, P1, P2 Pitch of wire rod or groove DC Trapezoidal clearance TC, TC1, TC2 Triangular clearance

Claims (8)

[Claims] 1. A developer carrying body for carrying a developer on a surface for developing a latent image formed on an image carrying body, and pressing the developer carrying body to the developer carrying body. In a developing device provided with a developer amount regulating body for regulating the amount of the carried developer, the developer is conveyed to an end surface of the developer amount regulating body which is in pressure contact with the developer carrying body. A developing device having parallel grooves provided in a direction substantially parallel to the direction. 2. The pitch of the parallel grooves provided on the end surface of the developer amount regulating member is approximately 0.1 to 20 times the particle diameter of the developer,
The depth of the groove is approximately 0.1 to 20 times the particle size of the developer.
2. The developing device according to claim 1, wherein the developing device is doubled. 3. The developing device according to claim 1, wherein the developer amount regulator is made of a rod having a circular cross section, and a wire is wound around the surface of the rod so as to have the same diameter. 4. The developing device according to claim 3, wherein the thickness of the wire wound around the surface of the developer amount regulator is approximately 0.1 to 20 times the particle diameter of the developer. 5. The developer amount control body is made of a rod having a circular cross section, and the surface thereof has a particle size of approximately 0.1 to 2 times the particle size of the developer.
A spiral groove having a pitch of 0 times, or a parallel groove having a pitch of approximately 0.1 to 20 times the particle diameter of the developer is provided in a direction parallel to the direction in which the developer is conveyed. 1. The developing device according to 1. 6. The developing device according to claim 3, wherein the developer amount regulator is driven to rotate by the developer carrier or driven to rotate by power. 7. The developer amount regulating body is made of a plate material having a spring property and is capable of pressing the developer carrying body, and the surface of the developer carrying body that is pressed has substantially the same particle size as the developer. 0.1
The developing device according to claim 1, wherein parallel grooves having a pitch of double to 20 times are provided in a direction substantially parallel to a direction in which the developer is conveyed. 8. 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.