JPS63307488A - Image forming device - Google Patents

Abstract

PURPOSE:To intensify the recovery electric field in a developer recovery area, and to improve the recovery efficiency of a developer in a non-exposed part by flattening the part, which faces a photosensitive body, of a sleeve incorporating a rotating magnet roll, and shortening and fixing the distance between the photosensitive body and the sleeve. CONSTITUTION:A magnetic brush developing machine 11 consists of a magnet roll 11a and a sleeve 11b whose part facing the photosensitive body 1 is flat, and an area A where a recording electrode 4 is provided in insulation from the sleeve 11b and development is performed simultaneously with exposure and an area B where the developer in the non-exposed part is recovered are divisionally constituted on the flat part of the sleeve 11b. Since the distance between the photosensitive body 1 and the sleeve 11b is shortened and fixed in the area B, the recovery electric field of the developer in the non-exposed part is strong and fixed to improve the recovery efficiency of the developer in the non-exposed part. As the result, the photographic fog is reduced to extend the margin of photographic fog, and storage of the developer is unnecessary.

Description

Detailed Description of the Invention [Summary] The present invention is an image forming apparatus that performs image exposure and development at the same time. By configuring the sleeve distance to be small and constant, the electric field applied to the photoreceptor is increased, improving the recovery efficiency of the developer in the non-exposed area and reducing fog.

[Industrial application field]

The present invention relates to an image forming apparatus that forms a toner image in a bright area on a photoreceptor irradiated with image light and transfers the toner image to display or recording paper.

Current copiers and high-speed, high-quality printers are
It is common to use an electrophotographic recording method. In this method, a photoreceptor is used as a recording medium, and recording is performed through the steps of uniform charging, image exposure, development, transfer, fixing, neutralization, and cleaning. This is the so-called Carlson process.

The Carlson process uses a corona discharger for uniform charging, transfer, and static elimination. Since the corona discharger is configured to apply a high voltage of several volts to the corona wire, it requires a high-voltage power source and is easily affected by humidity, dust, etc., so it has the disadvantage of low reliability. In addition, the toxicity of ozone generated in corona dischargers to the human body has become a problem.

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

Recently, in view of the above problems, an image forming method has been proposed that eliminates the need for a corona discharger and focuses on miniaturizing the apparatus.

Therefore, the present invention provides one method of % expression % [Conventional technology] FIG. 7 shows a schematic diagram of the prior art.

In the figure, a photoreceptor 1 includes a transparent substrate 1a and a transparent conductive layer 1b.
, a photoconductive layer 1c, and a transparent conductive layer Ji1b is connected to ground. A magnetic brush developing device 2 provided on the photoconductive layer IC side of the photoreceptor 1 is composed of a magnet roller 2a and a sleeve 2b, and the magnet roller 2a is freely rotatable. Furthermore, a strip-shaped recording electrode 4 is provided on the surface of the sleeve 2b and is insulated from the sleeve 2b with an insulating film 3. A voltage 6 having a polarity opposite to that of the carrier polarity (10 polarities in the figure) of the photoconductive layer 1c is applied to the recording electrode 4, and a voltage 7 having a polarity opposite to that of the recording electrode is applied to the sleeve 2b. This magnetic brush 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.

Image exposure means 8 is arranged on the transparent substrate 1a side of the photoreceptor 1. Examples of the exposure means include an optical system using an LED, an optical system using a liquid crystal shutter, an optical system using electroluminescence, an optical system using a laser, etc. The image exposure means 8 is connected to the optical axis of the exposure light. are arranged so that they intersect with the recording electrodes 4.

Next, the principle of image formation will be explained.

In the A section of the apparatus having the above configuration, when the photoconductive layer IC is imagewise exposed, photocarriers are generated in the photoconductive layer IC. Among the photocarriers, carriers having a polarity opposite to the voltage 6 applied to the recording electrode 4 move to the surface of the photoconductive layer 1c and form an electrostatic latent image 9.

In this way, in the exposed area (A), the capacitance of the photoconductive layer IC appears to increase, so the amount of adhered toner increases, resulting in a toner image with a certain degree of contrast between the exposed area and the non-exposed area.

Next, in section B, by applying a reverse voltage 7 to the sleeve 2b and creating a reservoir of developer, excess toner in the non-exposed section is collected into the magnetic brush developing device 2 by electrostatic force and magnetic force. At this time, a small amount of toner in the exposed area is also collected, but
Due to the electrostatic binding force between the latent image charge 9 and the toner charge, most of the toner remains on the photoreceptor 1, and a toner image 10 is formed.

[Problem that the invention seeks to solve]

A conventional image forming apparatus has a photoconductive layer I as shown in FIG.
The distance between C and the sleeve 2b increases as you go downstream in the direction of movement of the photoreceptor 1, and the electric field for recovering the developer in the non-exposed area becomes weaker accordingly. Therefore, the developer attached to the non-exposed area in the %ASl region cannot be completely recovered in the B area.

In addition, since the amount of developer accumulated in the B section changes, it was difficult to set the recovery conditions for the non-exposed area developer, such as the reverse bias for recovery and the distance between the photoreceptor 1 and the sleeve 2B. However, there is a drawback that fogging (staining of the background portion of the print) may occur and the contrast of the toner image 10 may be deteriorated.

[Means for solving problems]

FIG. 1 is a diagram explaining the principle of the present invention.

In the figure, 1 is a photoreceptor, and 8 is an image exposure means, which is the same as the prior art shown in FIG. The difference from the conventional technology is that a magnetic brush developing machine 11 is used instead of the conventional magnetic brush developing machine 2.
This is because we have established the following.

The magnetic brush developing device 11 is composed of a magnet roller 11a which functions and operates in the same manner as conventional ones, and a sleeve 11b whose portion facing the photoreceptor 1 is flat. The flat part of the sleeve 11b is divided into a simultaneous exposure and development area (area A) in which the recording electrode 4 is provided insulated from the sleeve 11b, and an area (area B) in which the developer in the non-exposed area is collected.

[Effect]

That is, by using the flat sleeve 11b as described above, the distance between the photoreceptor 1 and the sleeve 11b can be kept small and constant in the B area. Therefore, the recovery electric field for the developer in the non-exposed area is stronger and constant in region B compared to the conventional one, so that the recovery efficiency of the developer in the non-exposed area can be improved. As a result, fogging is reduced,
The fogging margin can be increased, and there is no need for a reservoir of developer that changes from time to time as in the conventional method.

〔Example〕

FIG. 2 is a diagram explaining the first embodiment of the present invention. In FIG. 0, reference numeral 21 is an endless photoreceptor film. As shown in FIG. 100μ-
on a transparent substrate 21a of polyethylene terephthalate,
A transparent conductive layer 21b of ITO (indium oxide) vapor deposited film is provided, and a CGL (charge generation layer) is further provided as a photoconductive layer.
21c and a CTL (charge transport layer) 21d, it is a functionally separated type with a thickness of approximately 10 μm and is provided with a hole transfer type organic photoconductive layer. Photoreceptor film 2 as above
The first transparent conductive layer 21b is connected to ground, and the photoreceptor film 21 itself is conveyed in the direction of the arrow in the figure by a power system (not shown) connected to a film drive roller 22.

23 is a magnetic brush developing machine, and a magnet roller 23a provided inside is rotatable. As shown in FIG. 4, the surface of the sleeve 23b is made flat at the portion facing the photoreceptor. Further, a conductive resin carrier is attached to a magnetic brush developing device 23 such as 0 or more, on which a strip-shaped copper foil type recording electrode 25 is attached to the area to be image exposed, which is insulated from the sleeve 23b by a polyimide film 24. A two-component developer 26 consisting of a magnetic toner and an insulating magnetic toner is filled and conveyed in the direction of the arrow in the figure by the rotation of the magnetic roller 23b.

The photoconductive layers 21c and 21d of this example were of a hole transfer type. Therefore, the recording electrode 25 is connected to the first power source 2.
7 to apply a negative voltage. This voltage is -100
v~-600V is suitable. Further, a positive voltage is applied to the sleeve 23b by the second power supply 28. This voltage is suitably 0 to +60V.

An LED array optical system 29 is installed as an image exposure means at a position facing the magnetic brush developing device 23 with the photoreceptor film 21 in between. The LED array optical system 29 uses a SELFOC lens array as a condenser lens. LP,
The optical axis of the D-array optical system 29 is arranged to intersect the center of the recording electrode 25, which has a width of 1 to 5 mm.

30 is a toner image formed on the photoreceptor film 21. 31 is recording paper, commonly known as plain paper. 3
2 is a conductive rubber roller for transfer, to which a voltage (+200 to +600V) is applied by a power source 33; 34 is a toner image electrostatically transferred onto the recording paper 31; the toner image is fixed on the recording paper 31 by a heat roller fixing device 35; The image becomes a semi-permanent recorded image 36.

37 is a residual toner image remaining on the photoreceptor film 21 after transfer. 38 is the charge of the residual toner image 37 and the photoconductive layer 2;
It is a removal light source that removes latent image charges in 1c and 21d. 39 is a toner image that has been neutralized and has lost its electrostatic binding force.

Next, the image recording procedure will be described.

By transporting the photoreceptor film 21 in the direction of the arrow and rotating the magnet roller 23a of the magnetic brush developing device 23, the developer 26 is transported in the direction of the arrow, and a voltage is applied to each of the recording electrode 25 and the sleeve 23b. Then, the LED array optical system 29 performs image exposure. Then (see FIG. 3), photocarriers are generated in the CGL 21c, and their internal pressure holes move within the CTLZLd to near the surface of the photoreceptor and become latent image charges. Based on the principle described in the section on prior art below, a charged toner image 30 held by the electrostatic force of the latent image charge is formed on the surface of the photoreceptor film 21.

Next, the toner image 30 is transferred to a recording paper 3 using a transfer roller 32.
1 is electrostatically transferred. The transferred toner image 34 is fixed onto the recording paper 31 by a fixing device 35, forming a semi-permanent recorded image 3.
6 is obtained.

On the other hand, the residual toner image 37 remaining on the photoreceptor film 21 after the transfer is neutralized using the static eliminating light source 38. The toner image 39, which has been neutralized and has lost its electrostatic binding force, is transferred to the magnetic brush developing device 2.
3, the scraping of the developer 26, and the electrostatic force caused by the voltage applied to the sleeve 23b collect and reuse the 0
The next image formation is performed at the same time as the residual toner image 39 is collected. There is no problem in collecting the residual toner image 39 and forming the next image at the same time, since the LED array optical system 29 and the developing device 23 are located opposite each other with the photoreceptor film 21 in between.

According to the embodiment described above, since the portion of the sleeve 23b of the magnetic brush developing device 23 facing the photoconductor 21 is made flat, the distance between the photoconductor film 21 and the sleeve 23b is was made small and constant. It also eliminates the need for a pool of developer that changes from moment to moment. Therefore, compared to the conventional technique, the recovery electric field in the developer recovery area is strong and constant, and the recovery efficiency of the developer in the non-exposed area can be improved. the result,
Since fogging of the toner image 30 on the photoreceptor film 21 can be reduced, the recorded image 36 formed on the recording paper 31 is
This results in a clear recorded image with high contrast.

In a second embodiment of the image recording apparatus of the present invention, a magnetic brush developing machine 40 shown in FIG. 5 is used as a developing machine.

The sleeve 40b of this developing device 40 has a flat portion facing the photoreceptor, as in the first embodiment. The difference from the first embodiment is that an insulator 4 is placed at the image exposure position on the flat part.
1, the recording electrode 42 is embedded, and the recording electrode 42 is also flat.

As a result, the portion of the sleeve 40b facing the photoconductor is flat, including the recording electrode 42, so that the developing device 40 is at least thicker than the insulator 41 and the recording electrode 42, compared to the first embodiment. can be brought closer to the photoreceptor. As a result, the electric field applied to the photoconductive layer increases, so
The recovery efficiency of the developer in the non-exposed area can be further improved.

As a third embodiment in which the present invention is applied to an image recording apparatus, a magnetic brush developing machine 43 shown in FIG. 6 is used as a developing machine.

As in the first embodiment, the sleeve 43b of the magnetic brush developing device 43 has a flat portion facing the photoreceptor, and a first insulating film 4 is placed at the image exposure position of the flat portion.
4 and a first recording electrode 45 are provided. In this example,
In addition, a second insulating film 46 and a second recording electrode 47 are provided in the non-exposed developer recovery area,
A developer recovery voltage is applied to 7.

As a result, since the developer recovery bias can be applied locally, the recovery efficiency of the developer in the non-exposed area can be improved as in the first embodiment.

In addition, the first recording electrode 45 and the second recording electrode 47 are
When embedded in the flat part of the sleeve as in the second embodiment,
The recovery efficiency of the developer in the non-exposed area is further improved.

In the above example, a two-component developer consisting of a conductive resin carrier and an insulating magnetic toner was used, but other two-component developers, such as iron powder, ferrite, etc. Magnetic Toner Furthermore, even if a conductive magnetic toner or an insulating magnetic toner is used as the -component developer, the same effects as in the above embodiments can be obtained.

Photoreceptor materials include organic materials such as phthalocyanine materials, PVK-TNF, azo dyes, and thiapyrylium dyes, and inorganic materials such as selenium photoreceptors, a-3i-CdS, and
Zinc oxide etc. can be used.

Further, as an image recording process, in the above embodiment, the residual toner remaining on the photoreceptor after transfer was collected by a magnetic brush developing machine, but a recording process in which the residual toner is removed with a brush cleaner, a blade cleaner, etc. may also be used. In the process, a roller transfer method was used in the example, but the same effects as in the above example can be obtained even if a corona transfer method is used.

Further, the present invention can be applied not only to an image recording device as in the above embodiment (but also to a display device in which a toner image on a photoreceptor is directly viewed without providing a transfer step), and sufficient effects can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, the part of the sleeve of the magnetic brush developing machine that faces the photoconductor is flattened, so that the recovery voltage can be applied to the photoconductor in the developer recovery area of the non-exposed area. The distance to the sleeve can be kept small and constant. It also eliminates the need for a pool of developer that changes from moment to moment. Therefore, compared to the conventional example, the recovery electric field in the developer recovery area is strong and constant, and the recovery efficiency of the developer in the non-exposed area can be improved. As a result, fogging of toner images can be reduced and fogging margins can be increased, so that clear images with high contrast can be obtained.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2 is a diagram explaining the first embodiment of the invention, Fig. 3 is a sectional view of a photoreceptor film, and Fig. 4 is a perspective view of the developing machine of the invention. Figure 5 is a perspective view of a developing machine in a second embodiment of the present invention, Figure 6 is a perspective view of a developing machine in a third embodiment of the present invention, and Figure 7 is a configuration diagram of a prior art. . In the figure, 1 is a photoreceptor, 3 is a vA edge film, 4 is a recording electrode, 5 is a developer, 6.7 is a power source, 8 is an image exposure means, 9 is a latent image charge, 10 is a toner image, 11.23 .40.43 is a magnetic brush developing machine, 21 is a photoreceptor film, 22 is a film drive roller, 24 is a polyimide film, 25 is a recording electrode, 26 is a developer, 27.28.33 is a power supply, 29 is an LED array, Optical system, 30, 34, 39 toner image, 31 recording paper, 32 transfer roller, 35 fixing device, 36 recorded image, 37 residual toner image, Figure 1 I of this research! Lj! Explanatory diagram Figure 2 The 10th award of the Ming Dynasty is given to Shun! The figure you want to see'M3
Figure 23 The current 111 of the present invention! ? Perspective diagram of electricity 4 Figure 40 ^ Meeting negative brush current 11 eyes skewer 1 (υ month's v, 20 draft thick wrinkles what 11; Agame suru nipo P Eikosaki's 11 different figure d W F11 43 Weifu Figure 6: Perspective view of the 3rd real flower of Ki 1 Rashi and current version of Fumoto Fan Ming; A++7 or current 11 aircraft.

Claims (1)

[Claims] Transparent substrate (1a), transparent or translucent conductive layer (1b)
and a photoconductive layer (1c), a magnetic brush developer (2) disposed on the photoconductive layer side of the photoconductor (1), and a magnetic brush developer (2). ) and a recording electrode (4) provided on the sleeve (2b) insulated from the sleeve;
4) and a reservoir of developer (5) provided downstream in the moving direction of the photoreceptor (1); and a first voltage application means (6) for applying a voltage to the recording electrode (4). , a second voltage applying means (7) having a polarity opposite to that of the first voltage applying means (6) for applying a voltage to the sleeve (2b), and a second voltage applying means (7) on the conductive layer side of the photoreceptor (1) and on the recording Electrode (4)
and an image exposure means (8) for performing image exposure, which is provided at a position facing the photoreceptor (1), and a magnetic brush developing device comprising a sleeve (11b) with a flat portion facing the photoreceptor (1). An image forming apparatus characterized by using (11).