JPH0797247B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention relates to an image forming apparatus for forming an image by arranging an image exposure unit and a developing device in opposition to each other with a photoconductor interposed therebetween, and a recording electrode provided on a sleeve of the developing device. The edge portion of the recording electrode is provided with an insulating coating so that spark discharge does not occur between the sleeve and the sleeve.

[Industrial application field]

The present invention relates to an image forming method in which a toner image is formed on a bright portion on a photoconductor that is irradiated with image light and is transferred to a display or recording paper.

Current copiers or high-speed, high-print quality printers generally use an electrophotographic recording system. This system is a so-called Carlson process in which recording is performed in the steps of uniform charging, image exposure, development, transfer, fixing, charge removal, and cleaning.

In the Carlson process, a corona discharger is used for uniform charging, transfer and static elimination. Since the corona discharger is configured to apply a high voltage of several KV to the corona wire, it requires a voltage power supply and is easily affected by humidity, dust, etc.
It has a drawback of low reliability. Further, ozone generated in a corona discharger produces an odor, and in recent years, ozone is harmful to humans.

Further, since the above-mentioned seven steps are required, there is a drawback that the device becomes complicated and the size becomes large.

In view of the above-mentioned problems, an image forming method has recently been proposed in which a corona discharger is unnecessary and the device is downsized.

[Conventional technology]

 FIG. 4 shows a schematic diagram of the prior art.

In the figure, the photosensitive member 1 is composed of a transparent substrate 1a, a transparent conductive layer 1b, and a photoconductive layer 1c, and the transparent conductive layer 1b is grounded. The magnetic brush developing machine 2 provided on the photoconductive layer 1c side of the photoconductor 1 comprises a magnet roller 2a and a sleeve 2b,
The magnet 2b is free to rotate. Further, a strip-shaped recording electrode 4 insulated from the sleeve 2b by an insulating film 3 is provided on the surface of the sleeve 2b. The photoconductive layer 1c is formed on the recording electrode 4.
Voltage 6 which is opposite to the carrier polarity (positive polarity in the figure) of
Is applied, and a voltage 7 having a polarity opposite to that of the recording electrode 4 is applied to the sleeve 2b. The developing device 2 is filled with a one-component developer or a two-component developer, and the developer 5 is conveyed in the direction of the arrow in the figure.

An image exposure unit 8 is arranged on the transparent substrate 1a side of the photoconductor 1. Examples of the image exposure means 8 include an optical system using an LED array, an optical system using a liquid crystal shutter, an optical system using electroluminescence, and an optical system using a laser. The image exposure means 8 is arranged so that the optical axis of the exposure light intersects the recording electrode 4.

Next, the principle of image formation will be described.

When the photoconductive layer 1c is imagewise exposed in the portion A of the apparatus having the above-described structure, photocarriers are generated in the photoconductive layer 1c. Among the photocarriers, carriers having a polarity opposite to the applied voltage 6 of the recording electrode 4 move to the vicinity of the surface of the photoconductive layer 1c and become latent image charges 9. In this way, in the exposed portion, the electrostatic capacity of the photoconductive layer 1c apparently increases, so that the amount of adhered toner increases, and a toner image with a certain degree of contrast is formed between the exposed portion and the non-exposed portion.

Next, in the portion B, the reverse voltage 7 is applied to the sleeve 2b and the developer is accumulated, so that the excess toner in the non-exposed portion is collected in the developing device 2 by electrostatic force and magnetic force. At this time, the toner in the exposed portion is also slightly collected, but the latent image charge 9
Due to the electrostatic restraint force of the toner charge, most of the toner remains on the photoconductor 1 and the toner image 10 is formed.

[Problems to be solved by the invention]

In the conventional image forming apparatus, spark discharge is often generated between the recording electrode 4 and the sleeve 2b. At that time, the recording electrode 4, the insulating film 3, and the sleeve 2b were damaged by the spark discharge. In addition, the recording electrode 4 and the sleeve 2b
Since the voltages 6 and 7 applied to the battery leak, the image may not be formed in some cases.

In view of the problems of the above-mentioned conventional device, the purpose of the present invention is to
An object of the present invention is to provide an image forming apparatus in which spark discharge does not occur between the recording electrode and the sleeve.

[Means for solving problems]

FIG. 1 is an explanatory view of the principle of the image forming apparatus according to the present invention, and FIG. 1B is an enlarged view of the vicinity of the recording electrode in FIG.

As shown in FIG. 1, the characteristic constitution of the present invention is that the recording electrode 4 is used.
This is the point where the insulating coating 11 is applied to the edge portions 4a and 4b.

The other parts of the configuration are the same as those shown in FIG. 4, and the same reference numerals are given and the description thereof is omitted.

[Action]

In the image forming apparatus shown in FIG. 4, it has been found that spark discharge is likely to occur between the edge portions 4a and 4b of the recording electrode 4 and the sleeve 2b. Therefore, the edge portions 4a, 4 of the recording electrode 4 are
By applying the insulating coating 11 to b, the spark discharge could be reduced.

〔Example〕

FIG. 2 shows a schematic diagram of an image recording apparatus embodying the present invention.

In the figure, 21 is an endless photoconductor film, which is a transparent conductive layer of iTO (indium oxide) vapor deposition film provided on a transparent substrate of polyethylene terephthalate with a thickness of 100 μm, and a CGL (charge generation layer) as a photoconductive layer. ) And a CTL (charge transport layer), an organic material having a thickness of about 10 μm is provided. Photoreceptor film 21 as above
The transparent conductive layer is connected to the ground, and the photoconductor film 21 itself is connected to the supporting roller 36 by a power system.
It rotates in the direction of the arrow in the figure.

Reference numeral 22 is a magnetic brush developing machine, and the magnet roller 22a provided inside the sleeve 22b rotates to convey the developer.

On the surface of the sleeve 22b, as shown in FIG. 3, a recording electrode 24 of a copper foil, which is insulated from the sleeve 22b by a polyimide film 23, is attached. Further, the edge portion of the recording electrode 24 is insulation-coated with a polyimide film 25 so that the recording electrode 24 and the sleeve 22b are not discharged. The insulating film 23 has a thickness of 25 μm, and the recording electrode 24 has a thickness of 35 μm.
m, the insulating coating 25 was 25 μm, and each was composed of a flexible printed board adhered with an adhesive. Further, the effective width of the recording electrode 24 is 5 mm or less, preferably 1 to 3 mm, and the width of the insulating film 25 is 10 mm or less, 3 to 5 mm. Reference numeral 26 is a lead pattern connected to a terminal for applying a voltage to the recording electrode 24. Magnetic brush developer as above
22 is a conductive magnetic toner with a toner resistance of 10 ² to 10 ⁸ Ωcm 29
And toner is conveyed in the direction of the arrow in the figure.

In this embodiment, since the hole transfer type photoconductive layer is used, a negative voltage is applied to the recording electrode 24 by the first power source 27.
This voltage is −100 to −500V, preferably −150 to −350V
Is appropriate. A positive voltage is applied to the sleeve by the second power source 28. This voltage is 0 to 50V, preferably +10 to + 30V.

Then, an LED optical system 29 including an LED array and a SELFOC lens array is installed as an image exposing means at a position facing the recording electrode 24 across the photoconductor film 21.

In the image forming unit described above, the charged toner image 30 held by the electrostatic force of the latent image charge is formed on the surface of the photoconductor film 21 by the procedure described in the section of the related art.

Next, the toner image 30 is electrostatically transferred onto the recording paper 32 using the transfer conductive rubber roller 31 to which a voltage is applied. The transferred toner image is fixed on the recording paper 32 by the thermal fixing device 33,
A semi-permanent recorded image 34 is obtained.

On the other hand, after the transfer, the residual toner remaining on the photoconductor film 21 is discharged by using the discharging brush 35. The toner that has been destaticized and has lost the electrostatic restraint force is collected by the magnetic brush developing device 22 and reused.

According to this embodiment, the insulating coating 25 is formed on the edge portion of the recording electrode 24.
The spark discharge between the recording electrode 24 and the sleeve 22b could be extremely reduced by applying the above. As a result, damage to the recording electrode 24, the insulating film 23, and the sleeve 22b was reduced, and the service life of this portion was extended. In addition, the recording voltage 27,2
Since there was no leak of 8, the recorded image 34 did not have faintness or missing print, and a clear recorded image was obtained.

Further, since the recording electrode 24 is composed of the flexible printed board, the total thickness of the insulating film 23, the recording electrode 24, and the insulating coating 25 can be reduced, and the attachment to the sleeve 22b is simplified.

〔The invention's effect〕

According to the present invention, by providing the insulating coating on the edge portion of the recording electrode, the spark discharge between the recording voltage and the sleeve can be extremely reduced. As a result, the recording electrode, the insulating film and the sleeve were not damaged, and the life of the image forming portion was extended. Further, since there is no recording voltage leak, the toner image formed on the photoconductor is a clear toner image without blurring or print missing.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of the present invention, FIG. 2 is a schematic diagram in which the present invention is applied to an image recording apparatus, FIG. 3 is a perspective view of a developing machine according to the present invention, and FIG. Indicates. In the figure, 1 is a photoconductor, 2 is a magnetic brush developing machine, 2b is a sleeve, 3 is an insulating film, 4 is a recording electrode, 5 is a developer, 6 is a first voltage applying means, and 7 is a second voltage applying. Means, 8 is an image exposing means, 9 is a latent image charge, 10 is a toner image, and 11 is an insulating coating.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G03G 15/08 502 F 15/09 Z B41J 3/21 Z

Claims (1)

[Claims] 1. A photoconductor (1) comprising at least a transparent conductive layer (1b) and a photoconductive layer (1c), and a photoconductive layer (1c) side of the photoconductor (1), A magnetic brush developing machine (2) having at least a sleeve (2b) for carrying a developer, a recording electrode (4) provided on the sleeve (2b) so as to be insulated from the sleeve (2b), and the recording electrode. First voltage applying means (6) for applying a voltage between (4) and the conductive layer (1b), and a voltage having a polarity opposite to that of the first applying means (6) with the sleeve (2b). Second voltage applying means (7) applied between the electroconductive layer (1b) and the electroconductive layer (1b) side of the photoconductor (1) and at a position facing the recording electrode (4). An image forming apparatus provided with an image exposing means (8) for performing image exposure, comprising: an edge portion (4a, 4b) of the recording electrode (4). Image forming apparatus characterized by subjected insulating coating (11).