JPH01134380A - Developing device - Google Patents

Abstract

PURPOSE:To obtain stable pressure by pressing a blade for triboelectrification not with only the elastic force of a support member, but by further using a spring when a thin film of a single-component developer is formed on the surface of a developing roll and the blade is pressed against the thin film to develop an electrostatic latent image formed in the thin film. CONSTITUTION:A developing device 2 is arranged nearby the photosensitive body 1 of a copying machine, etc., a housing 2a which contains the single- component developer is provided in the device 2, and the developing roll 3 which is near the photosensitive body 1 is arranged in the housing and rotated in the same direction as the photosensitive body 1 rotates. The blade 4 for triboelectrification which is formed of soft resin, etc., is provided nearby the roll 3 and its reverse surface is pressed by the elastic support member 5 such as a leaf spring fixed to a fixture 8, but a lever 9 is fitted to the fixture 8 through a prismatic fitting member 7 and its end part is tensed by a tension spring 10 fitted to a bracket 2b. Consequently, even if the blade 4 wears off, a decrease in pressing force is evaded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device for developing an electrostatic latent image using a one-component developer.

[Conventional technology]

2. Description of the Related Art Copying machines, printing machines, printers, etc. that conventionally utilize electrophotography include those that employ a developing device that uses a one-component developer.

Further, in the above-mentioned developing device, a triboelectric charging blade a as shown in FIG. There is one in which an electrostatic latent image formed on the surface of a photoreceptor d is developed.

[Problem that the invention seeks to solve]

In the developing device using the frictional charging blade a, as shown in Fig. 3, when the blade a is not worn out, the blade a and the developing roll b are in line contact, and moderate pressing is good because a force is obtained. However, as shown in Fig. 4, when the blade a wears out, the blade a and the developing roll b come into surface contact and the pressing force decreases, resulting in variations in copy density. There were problems such as deterioration in concentration maintenance.

[Means and effects for solving the problems] This invention was made for the purpose of improving the above-mentioned problems, and a one-component developer is applied to the surface of the developing roll by a triboelectric charging blade that is pressed against the circumferential surface of the developing roll. In a developing device that forms a thin layer of and develops an electrostatic latent image formed on the surface of a photoreceptor using this thin layer, the frictional charging blade is brought into pressure contact with the developing roll by a biasing means. An object of the present invention is to provide a developing device in which a blade is always pressed against a developing roll with constant pressure regardless of the friction of the blade.

〔Example〕

An embodiment of the present invention will be described in detail with reference to the drawings. In the drawing, 1 is a photoreceptor of a copying machine, etc., and 2 is a developing device main body installed near the photoreceptor, and a housing 2 containing a one-component developer.
a, and the photoreceptor 1 is placed inside this housing 2a.
A developing roll 3 is provided adjacent to and rotatable in the direction of the arrow.

A frictional charging blade 4 is placed near the developing roll 3.
is provided so as to be in contact with the circumferential surface of the developing roll 3.

The blade 4 is made of soft resin, etc., and is fixed to the lower end side of a blade support member 5 made of an elastic body such as a leaf spring, and the upper end side is shaped like an arc in the opposite direction to the developing roll 3. The prismatic mounting, which is curved and whose upper end is rotatably supported by the blade support shaft 6, is fixed to the member 7 with a fastener 8 such as a screw.

In addition, one end of the lever 9 is fixed to the surface of the member 7 opposite to the mounting part of the blade support member 5 by a fixing tool 8, and the other end of the lever 9 is protruded diagonally upward. A biasing means 10 such as a tension spring is stretched between the tip of the lever 9 and a bracket 2b provided on the housing 2a to bias the blade 4 in a direction to press the blade 4 against the developing roll 3.

Incidentally, the biasing means 10 may be a spiral spring as shown in FIG.

〔Effect of the invention〕

As described in detail above, in this invention, the frictional charging blade 4 that forms a thin layer of developer on the circumferential surface of the developing roll 3 is pressed against the circumferential surface of the developing roll 3 using the urging means 10. Therefore, even if the blade 4 wears out, the pressing is less affected by the force compared to the conventional blade 4 which is pressed by the elastic force of the blade support member, so the blade 4 is always pressed against the developing roll 3 with a stable pressure. You will be able to press it to

As a result, a constant amount of developer can be supplied to the surface of the developing roll 3, so copies with stable density can be obtained over a long period of time, and a biasing means 10 for pressing the blade 4 against the developing roll 3 is added. It can be implemented easily and inexpensively.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, FIG. 2 is an explanatory diagram showing another embodiment, and FIGS. 3 and 4 are explanatory diagrams of a conventional system. 1 is a photoreceptor, 3 is a developing roll, 4 is a frictional charging blade, and 10 is a biasing means. Applicant Fuji Xerox Co., Ltd. Agent Patent Attorney Masaaki Yonehara

Claims (1)

[Claims] Frictional charging plate 4 pressed against the circumferential surface of the developing roll 3
In a developing device that forms a thin layer of one-component developer on the surface of the developing roll 3 and develops an electrostatic latent image formed on the surface of the photoreceptor 1 with this thin layer, the above-mentioned triboelectric charging blade 4 is attached. A developing device which is brought into pressure contact with a developing roll 3 by a force means 10.