JPS58118677A - Developing device - Google Patents

Abstract

PURPOSE:To realize a uniform developing agent layer and tribocharging so as to obtain good developed pictures, by applying the developing agent uniformly with a fibrous brush contacted with the upper part of the conductive roller, and by impressing a developing bias upon the upper part of the roller. CONSTITUTION:A fibrous brush 6 fixed to a hopper 4 is contacted with the surface of the upper part of a conductive roller 3, and an AC voltage is applied across the roller 3 and a photosensitive body 1 by a power source 7. A developing agent layer 5' is applied on the surface of the roller 3 with a brush 6. In the course of applying the developing agent on the roller 3, the brush fiber makes fine vibrations and sufficiently loose the developing agent and uniform applying of the developing agent is realized by eliminating applying unevenness. Moreover, the developing agent which remains on the roller 3 and reaches the brush 6 is also disturbed and vanished. At the same time, tribocharging is performed by the vibration of the brush fiber. The developing agent on the roller 3 make reciprocative flying motions between the roller and the photosensitive body 1 by a developing bias. Therefore, the developing agent is uniformly applied, and the uniformly applied developing agent together with the effect of the tribocharging results in good pictures.

Description

[Detailed description of the invention] This invention relates to a developing device K using component developers.

A one-component developer is used, a minute gap is provided between the developer carrier and the latent image support, and an alternating electric field is applied to this minute gap to transfer the developer between the developer carrier and the latent image support. fly back and forth and leave developer in the latent image area.
The illusionary device is short and short. In such an fA excavator, the agent layer on the developer-carrying means is thin, and the developer is not disturbed between the latent image support and the mechanical abrasion support in the viewing area. If the developer layer is not uniformly applied to the developer carrier, density unevenness will occur in the obtained developed AM image. However, it is difficult to uniformly apply a developer layer, and it is particularly difficult to uniformly apply a non-magnetic one-component developer.

Conventionally, as a method of applying a non-magnetic component developer to a carrier while controlling the layer thickness, there is a method in which an elastic plate made of rubber or the like is brought into contact with the carrier. However, with this method, even though it is possible to regulate the developer's IT, streaks are likely to occur on the paper.

The purpose of the present invention is to provide a device with a simple structure that can solve the above-mentioned disadvantages.

The invention will now be described in detail with reference to the following aspects.

In the figure, it is an electrophotographic photoreceptor provided on the conductive support drum 20 times and rotates in the direction of the arrow.

As the photoreceptor 1 rotates, an image area (consisting of an image area to which electrostatic latent mC visual agent is to be applied and a non-1111 image ff1sL to which no developer should be attached) is first formed by known means as it rotates. This latent image is the present gI Tojin, which will be described later.
The device is developed with an insulating non-magnetic component developer. The obtained developer gI is then transferred to paper by known means, and first, it is rolled onto paper by known means. On the other hand, the photoreceptor after the transfer is cleaned by known means.

Next to the developing device, reference numeral 6 denotes a conductive roller made of stainless steel, aluminum, etc., which rotates in the direction of arrow I:I. The direction of rotation of the row 23 is arbitrary, but it is preferable to rotate the row 23 once in the rotation direction opposite to the rotation direction of the photoreceptor 1 at approximately the same speed as the circumferential speed of the photoreceptor 1, as shown in the figure. From the viewpoint of the quality of the developed image obtained, it is preferable that there be no relative speed difference between the roller 6 and the photoreceptor 1 in the developing section that applies the developer to the photoreceptor.

A minute gap is provided between the roller 6 and the photoreceptor 1 in the developing section. This gap is larger than the thickness of the developer layer 5' carried by the roller 6 on its surface and conveyed to the developing section. Therefore, this interval 111, for example, 100μ to 5
00μ, preferably 150μ to 600μ. If this distance is too large, the electrostatic force exerted by the electrostatic latent image on the photoreceptor 1 on the developer 1 & agent 5' applied on the surface of the developer support row 23 will become hooked, resulting in a decrease in image quality, especially in fine detail. It is difficult to visualize the rock by developing it. If this distance is too narrow, the developer coated on the surface of the developer support roller 3 will be compressed between the developer support roller 3 and the photoreceptor 1, and the thickness of the developer layer 5' will be approximately 50 μm. This is related to the fact that preferably about 80 μm or more is required.

Now, this is a hopper that accommodates the 4#i insulating, non-magnetic one-component developer 5 and supplies it to &m of the row 26. and 6
A fiber brush serves as a developer application means, and is fixed to the hopper 4 and brought into contact with the surface of the roller 3. The brush 6 applies the developer layer 5' to the surface of the roller 6 while controlling the layer thickness. At this time, since the brush fibers vibrate minutely due to sliding contact with the surface of the roller 3, the developer is sufficiently loosened and uniformly applied to the surface of the row 26 without streaks or the like. Further, the second developer layer pattern (negative image pattern of developed image im*) remaining on the surface j of the row 23 after passing through the developing section is also disturbed by the brush 6 and eliminated. Further, the vibration described above imparts a triboelectric charge to the developer. Therefore, it is preferable to select a brush fiber material that can sufficiently impart a frictional charge of polarity opposite to the t-position of the image area to the developer.

As the brush 6, a material obtained by electrostatically flocking polymeric synthetic fat fibers onto rubber, sponge, or the like can be suitably used. The brush fiber has a thickness of 10 denier or less, preferably 2 denier or less, and a length of 10 mm or less, preferably #i2 m.
m or less is appropriate. The flocking density is 60,000/ctA.
Above, preferably 100,000 pieces/C- or more is appropriate.

The surface of the roller 6 may be smooth, but the surface of the roller 6 may be smooth.
3 Increase the thickness of the iJ4 image agent layer applied to the surface, and
In order to increase [lf, the surface of the developer carrying row 23 may be roughened so that the developer 5 is caught by the movement of the developer carrying row 23 in the direction of the arrow.

Even if the surface roughness of the developer carrying roller 3 is smaller than the size of the developer particles, this effect is sufficiently obtained.

For example, for a developer particle size of 7 microns on average, an unevenness of 1 micron to 2 microns is sufficiently effective. These irregularities can be easily created, for example, by rubbing the surface of the cylindrical developer carrying roller 6 made of stainless steel in the longitudinal direction with 600 mm sandpaper.

A 7ti developing bias basket source is connected to the roller 6.

Power supply 7 voltage A, C, voltage source or A, C, '-voltage to developer strip 1! It is also possible to use a voltage source with a polarity opposite to the polarity, C, and voltage of 1 tatami. The latter is better because it can further prevent fogging and reproduce halftones more faithfully. In any case, this is 1! When an alternating electric field is formed in the developing device 4A by the L source 7, the developer layer 5' flies from the surface of the roller 6 onto the photoreceptor 1 and adheres to both the image 1 area and the non-m image area, and then the electric field When the direction changes, the developer layer roller 3 attached to the outer image gJI section erodes by 4% and returns to normal. l[Ij The developer attached to the image area leaves the dust image area as it rotates while remaining attached to the photoreceptor 1. Even in a developing device in which the developer is applied to the photoconductor by flying the developer in the developing section, according to the present invention, since the developer layer conveyed to the developing section is uniform, a uniform dl can be obtained.

In addition, in order to even out the developer layer 51 applied to the roller 6 by the brush 6, at a position between the brush 6 and the developing section,
A blade 8 made of a flexible elastic material such as rubber or other synthetic resin may be brought into contact with the roller 6 as shown by the broken line with a light pressure that does not restrict the amount of developer. Since this blade 8 also imparts a jI triboelectric charge to the developer, it is preferable to select a material that sufficiently imparts a triboelectric charge having a polarity opposite to the potential of the image area to the developer.

In order to allow the developer to pass through without being blocked, the blade 8tj is preferably oriented in a direction where it is dragged by the rotation of the roller 3 as shown in the figure, and furthermore, it is preferably provided so that its belly is in contact with the roller 3.

In any case, according to the present invention, a sufficiently uniform developer layer can be obtained and sufficient triboelectric charge can be applied to the developer, so that a good 1IiiiIII image can be obtained.

[Brief explanation of drawings]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a detailed explanation of the present invention, reference numeral 1 denotes an electrophotographic photoreceptor, 6 a developer co-carrying roller, 4 a disciplinary agent supply hopper, 5 a one-component non-magnetic developer, and 6 a brush. Applicant Canon Co., Ltd.

Claims (1)

[Claims] m A movable developer carrier having a smooth or rough surface that supports a monocomponent developer and is disposed opposite to the image support with a small gap therebetween, and a supply supplying the monocomponent developer onto the surface of the movable developer carrier. a fiber brush for applying the developer supplied by the supplying means in a layered manner onto the surface of the movable developer carrier; and a development bias applying means for forming an alternating electric field in the minute rise. .