JPS6132075A - Non-magnetic one component developing device - Google Patents

Abstract

PURPOSE:To develop the solid black part of a wide area, too, without varying a density by setting the roughness of the surface of a developer supplying member to a roughness having a prescribed value or above. CONSTITUTION:A developer 3 is brought to a squeezing friction member 2, and a charge is given, and the developer is formed to a thin layer shape by an image forming member 4, carried to a holding body 6, and converts a latent image 5 to a visible image. Between the holding body 6 and the carrying body 1, a bias voltage is applied by a voltage source 7 and the developing efficiency is raised. Subsequently, EPDM rubber of the surface of the developer feeding member 2 is formed to a rough surface by using a sand paper of #60, and an average surface roughness (Ra) of its center line is set to a roughness of >=5mu. In this way, the development of the solid black part of a wide area can be executed without varying a density, but when the average surface roughness is set to >=5mu, a problem is settled as shown in the chart.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to the field of electrophotographic copying machines, and more specifically:
This invention relates to an improvement in a developing device using a non-magnetic one-component developer.

Conventional technology and its problems When developing a latent image using a non-magnetic one-component developer in an electrophotographic copying machine, the developer is generally placed between a developer supply member and a developer supplying member that are in pressure contact with each other while rotating. The developer is sequentially supplied from the developer supply member to the developer carrier while being rubbed with the carrier and given a predetermined electric charge. The developer supplied to the developer carrier is formed into a thin layer by a suitable image forming member, and is attracted by electrostatic force to an electrostatic latent image carrier rotating adjacent to the image forming member. to visualize the latent image.

Conventional non-magnetic one-component developing devices in such electrophotographic copying machines, when developing a solid black area over a wide area, develop the density of the image on the carrier (specifically, the density of the image on the carrier (specifically, the There was a problem in that the density of the image corresponding to the part became lighter.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a non-magnetic one-component developing device that can solve these problems and provide a good visible image with uniform density even when developing a solid black area over a wide area. This is the purpose.

Means for Solving the Problems and Their Effects The present invention has been made based on repeated examinations of the factors governing image density in the non-magnetic single-component developing device as described above. We have found that the above problem is solved by coarsening on the value edge. Thus, according to the present invention, there is provided a developer supply member and a developer carrier that are in pressure contact with each other while rotating, and further includes an electrostatic latent image holder that rotates adjacent to the developer carrier, A non-magnetic one-component developer is rubbed between the developer supply member and the developer carrier, is supplied from the developer supply member to the developer carrier while being given a predetermined charge, and is further charged with the electrostatic charge. A non-magnetic one-component developing device that is sent to a latent image holding member and develops the latent image into a visible image, wherein the surface roughness (center line average surface roughness) of the developer supplying member is 5 μm or more. A developing device is provided.

According to the developing device of the present invention, the surface of the developer supplying member is rough, so that when the supplying member comes into pressure contact with the developer carrier, image density is maintained in order to provide sufficient charge and amount of developer. It is considered possible to do so.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the features of the present invention, the present invention will be described below with reference to embodiments shown in the drawings.

Embodiment FIG. 1 shows a typical example of a non-magnetic one-component developing device to which the present invention is applied. As shown in the figure, the developer carrying member 1 and the developer supplying member 2 are in pressure contact with each other while rotating.
Developer material 3 is supplied from a suitable hopper (not shown).

The developer 3 is rubbed and charged at the pressure contact portion between the carrier 1 and the supply member 2, and a part of the developer 3 rotates while being held on the surface of the supply member as the supply member rotates. , and returns to the original pressure-welding position while being formed in layers by a suitable member 8. In this way, the charged developer is sequentially sent from the supply member 2 to the carrier 1. The developer supplied to the carrier is formed into a thin layer by the image forming member 4 and is conveyed to the holder 6 which holds the electrostatic latent image 5, thereby converting the latent image 5 into a visible image. Holder 6 and carrier 1
During this time, a bias power source is applied by a voltage source 7 to improve the developing efficiency.

Development was carried out under the following conditions using the developing device having the above configuration. The carrier 1 is a cylindrical member made of SUS with a diameter of 13 mm, a thickness of 1 mm, and a specific resistance of 106.
A material coated with a phenolic resin of Ω cm was used, and as the supply member 2, a SUS cylindrical member with a diameter of 6 ml'Il was coated with an EPDM rubber layer with a wall thickness of 2 mm and a specific resistance of 103 Ω cm. Further, as the developer 3, one obtained by dispersing carbon black in a styrene acrylic resin and having a particle size of 10/jm was used. The holder 6 was a cylindrical member with a diameter of 61I11 on which a Se-based photoreceptor was deposited, and an electrostatic latent image 5 with a surface potential of 950V was formed thereon. The layer forming member 4 is made of SUS 0, 1
Made of mm plate spring material, 50g/cm ~ 500g/
It was brought into pressure contact with the carrier 1 within a range of cm. The layer forming member 8 is
It was made of a 0.1 mm SUS plate spring material and was brought into pressure contact with the developer supply member 2. The gap between the electrostatic latent image holder 6 and the developer carrier 1 was 150 μm.

While rotating the holder 6 at a circumferential speed of 85 rnm/sec, and applying a superimposed DC voltage of 500 Vi, AC voltage of 800 V, P, 300 V as a developing bias voltage, the developer carrier 1 and the developer supply member are The peripheral speed is 127 by pressing the
．． Rotated 5 mm in 7 seconds.

In this way, the EPDM rubber on the surface of the developer supply member 2 is
By roughening the surface using No. 60 sandpaper, the center line average surface roughness (Ra) is 1 μm to 10 μm.
When an image consisting of a solid black area was developed under the above-mentioned conditions while changing the value of m within the range, the results shown in FIG. 2 were obtained. Note that in order to roughen the surface of the supply member 2, in addition to using sandpaper, means such as polishing with a lathe may be used. In the figure, L is a length corresponding to the circumferential length of the developer carrier 1.

As can be understood from FIG. 2, when the surface roughness of the developer supplying member is low, when a wide area of solid black area is developed, the density of the image corresponding to the area longer than the circumference of the carrier 1 is reduced. Although it is thinner, such a problem will be resolved if the surface roughness becomes 5 μm or more.

Effects of the Invention As described above, the developing device of the present invention provides good performance with no change in image density even when developing a wide solid black area using a non-magnetic component developer. It can give a visible image.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a typical example of a non-magnetic one-component developing device to which the present invention is applied, and FIG. 7 is a graph showing that the image density changes depending on the surface roughness Ra of the developer supplying member.

Claims (1)

[Claims] A developer supplying member and a developer carrier that are in pressure contact with each other while rotating, and an electrostatic latent image holder that rotates adjacent to the developer carrier, and a non-magnetic one-component developer, The developer is rubbed between the developer supply member and the developer carrier and is supplied with a predetermined charge from the developer supply member to the developer carrier, and further sent to the electrostatic latent image carrier. A non-magnetic one-component developing device that develops the latent image into a visible image,
Surface roughness of the developer supply member (center line average surface roughness)
A developing device characterized in that the diameter is 5 μm or more.