JPS6128977A - Non-magnetic one component developing device - Google Patents

Abstract

PURPOSE:To constitute a titled device so that a carrying quantity of a developer carried toward a holding body of an electrostatic latent image is contant at all times, and to execute a uniform and stable development by setting a surface roughness of a developer carrying surface to within a specified range. CONSTITUTION:When moving onto an outside peripheral surface 6c of a carrying body roll 6 from a carrying roll 5, a developer 2 is brought to triboelectrification by a slide-contact of both the rolls 5, 6, and a sufficient charge is given. Also, the developer 2 on the carrying body roll 6 reaches a contact position of the second blade 4 by a rotation of its roll 6, it is formed to a developer layer of a prescribed thickness by this blade 4, and also, a sufficient charge is given to its developer layer by a slide-contact of the blade 4 and the roll 6. In this case, a surface roughness of the outside peripheral surface 6c of the carrying body roll 6 is set to a range of 0.1-0.5mum by a center line average surface roughness (Ra), therefore, a carrying quantity of the developer 2 by the carrying body roll 6 is constant even if it is used continuously for many hours. That is to say, the layer thickness of the developer layer formed by the blade 4 is constant.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a developing device used in an electrophotographic device or the like, and more specifically, to developing a developer supplied on a carrier to a predetermined thickness using a layer forming member. The present invention relates to a nonmagnetic one-component developing device that has a developer layer and conveys this developer layer to an electrostatic latent image to develop the electrostatic latent image into a visible image.

(Prior Art) In a conventional developing device of this type, developer stored in a hopper is conveyed to the carrier by a conveyance roll that contacts the carrier and rotates in the same direction as the carrier, and then conveys the developer to the carrier. The developer conveyed onto the carrier is formed into a developer layer of a predetermined thickness by a layer forming member that is in line contact with the carrier with uniform pressure, and this developer layer is transferred to the static developer held on the carrier. It is known that the electrostatic latent image is supplied to an electrostatic latent image to develop the electrostatic latent image into a visible image.

In such a developing device, the center of gravity surface roughness R of the carrier is
It is known that when a) is 10 μm or more, the developer adheres to the surface of the carrier and is no longer attracted to the electrostatic latent image. The surface roughness (Ra) is said to be less than 10 μm.

(Problem to be solved by the invention) However, the surface roughness of the carrier is 10 μm as described above.
Even when the value is less than m, the thickness of the developer layer formed on the carrier becomes thinner during long-term operation, that is,
There was a problem in that the amount of developer transported was reduced.

(Means for Solving the Problems) - In order to solve the problems, the present invention provides an electrostatic charge held on a carrier by a developer layer formed on the carrier by a layer forming member. A non-magnetic one-component developing device for developing a latent image into a visible image, characterized in that the surface roughness of the carrier is in the range of 0.1 to 0.5 μm in terms of center line average surface roughness (Ra). It is something.

(Example) Examples of the present invention will be described below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention.

In the figure, 1 is a hopper that stores developer 2;
At both ends of the opening 1a of the hopper 1, first
and a second blade 3.4 is fixed. Below the hopper 1, a conveyor roll 5 is moved around the material shaft 5a by an arrow 5b.
It is arranged so that it can rotate in the direction. The free end side of the first blade 3 is in contact with the outer peripheral surface 5c of the transport roll 5 with a predetermined pressure. 6 is a carrier roll, and the material shaft 6a
It is rotatable in the direction of arrow 6b centering on the transport roll 5.
Its position is set so that it comes into contact with the outer circumferential surface 5c of , with a predetermined pressure. The outer peripheral surface 6 of this carrier roll 6
The free end side of the second blade 4 is in contact with c at a predetermined pressure. On the other hand, at a position facing the carrier roll 6,
A holder roll 8 that holds the electrostatic latent image 7 is mounted so as to be rotatable in the direction of an arrow 8a. In addition, a bias power source in which an AC voltage is superimposed on a DC voltage is applied to the carrier roll 6 by a bias power source 9.
It is.

The developer 2 stored in the hopper 1 is a non-magnetic 1
It is a component-based developer, in which pigments such as carbon and polarity control agents such as metal-containing azo dyes are dispersed in various thermoplastic resins such as styrene resins and acrylic resins, and then pulverized and classified to produce
The size is 20μ. In some cases, in order to improve fluidity, 0.5
Hydrophobic silica may be added in a range of .about.20 weight percent. Next, the first blade 3 is made of a stainless steel plate with a predetermined thickness, and contacts the outer circumferential surface 5c of the transport roll 5 with a linear pressure that prevents the developer 2 from spilling from between the blade 3 and the transport roll 5. are doing. The second blade 4 is also made of a stainless steel plate, and functions as a layer forming member that forms a developer layer of a predetermined thickness on the outer circumferential surface 6c of the carrier 6.

Next, the surface roughness of the outer peripheral surface 6c of the carrier roll 6 is 0.1 μm to 0.5 μm in terms of center line surface roughness (Ra).
It is processed so that it falls within the range of m.

That is, the inventor investigated the amount of developer carried by the carrier by varying the centerline surface roughness (Ra ) of the carrier surface, and found that the centerline surface roughness (Ra ) was 0.1 μm to 0.5 μm. It has been found that within this range, the amount of developer conveyed toward the electrostatic latent image can be maintained constant even during long-term use. Figure 2 shows that the center line average surface roughness is 0.05 μm.
, 0.3 μm and 0.7 μm, curves A and B show the experimental results, respectively.

This is indicated by C. As is clear from the figure, when the surface roughness is 0.3 μm (curve B), the amount of developer conveyed by the carrier remains almost constant even during long-term continuous operation; It does not gradually decrease as in

The operation of this embodiment configured as described above will be described.

First, the developer 2 in the hopper 1 falls from the opening 1a due to its own weight and is supplied onto the outer peripheral surface 5C of the transport roll 5. The developer 2 thus supplied is conveyed toward the carrier roll 6 by the conveyance roll 5 . At the abutment between the two rolls 5 , 6 the developer is transferred from the transport roll 5 onto the outer circumferential surface 60 of the carrier roll 6 . During this movement, the developer is triboelectrically charged due to the friction between both rolls 5.6, and a sufficient electric charge is imparted to the developer. The developer on the carrier roll 6 reaches a contact position with the second blade (layer forming member) 4 due to the rotation of the roll 6, and is formed into a developer layer of a predetermined thickness by the blade 4.

Furthermore, the friction between the blade 4 and the roll 6 imparts a sufficient charge to the developer layer.

Here, in this embodiment, as described above, the surface roughness of the outer circumferential surface 6C of the carrier roll 6 is set in the range of 0.1 to 0.5 μm in terms of center line average surface roughness (Ra). Even after continuous use for a long time, the amount of developer conveyed by the carrier roll 6 remains constant.

That is, the thickness of the developer layer formed by the blade 4 is constant.

In this way, the carrier roll 6 after passing through the blade 4
A developer layer having a constant layer thickness is formed on the outer circumferential surface 6C. As the roll 6 rotates, this developer layer reaches a position facing the holder 8. The holder 8 is rotating in the direction of the arrow 8a, and when the electrostatic latent image 7 held on its outer peripheral surface reaches this opposing position, the carrier roll 6 is rotating while being applied with a bias voltage. Due to the electric field between the electrostatic latent image 7 and the carrier roll 6, the developer on the carrier roll 6 is attracted to the electrostatic latent image 7 and adheres to the latent image 7. In this way, the latent image 7 is developed.

(Effects of the Invention) As explained above, according to the present invention, the surface roughness of the developer carrying surface, which is the surface of the carrier, is reduced to the center line average surface roughness R.
Since the thickness was set within the range of 0.1 to 0.5 μm in a), the electrostatic latent image is conveyed toward the holder holding the electrostatic latent image. The amount of developer conveyed is always constant, and uniform and stable development can be performed.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic curve diagram showing changes in the amount of developer conveyed due to differences in surface roughness of the carrier. 2... Developer, 4... Second blade (layer forming member), 6... Carrier roll, 6C... Outer peripheral surface, 7... Electrostatic latent image. Patent applicant Fuji Xerox Co., Ltd. Figure 2 (Time →

Claims (1)

[Claims] In a non-magnetic one-component developing device that develops an electrostatic latent image held on a support body into a visible image by a developer layer formed on the support body by a layer forming member, the surface roughness of the support body The center line average surface roughness (Ra) is 0.1 to 0.5
A non-magnetic one-component developing device characterized in that it is in the μm range.