JPS6147967A - Photosensitive body and image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a photoreceptor having a novel configuration and an image forming apparatus using this photoreceptor.

[Prior art and its problems]

A bipolar photoreceptor is used, and the photoreceptor is primarily charged with a predetermined polarity, and image exposure, development, etc. are performed to obtain the first W.
A t-image or a first visible image is formed, and the photoreceptor on which the first latent image or first visible image is still formed is subjected to secondary charging with a polarity opposite to that of the primary charging.

A method is known in which a two-color image is formed by performing imagewise exposure, development, etc., but in order to uniformly perform the secondary charging, a corona ion flow control device is provided at or near the opening for corona ion irradiation. A method using a corona discharger equipped with a screen has been proposed. The screen is made up of a conductor part and an insulator part, and a high bias is applied to the conductor part side.

When charging is performed using a corona discharger equipped with such a screen, for example, toner scattered inside the machine or toner remaining on the photoconductor without being cleaned may have polarity opposite to the screen bias. Charged toner gradually accumulates on the screen due to electrostatic adsorption force, clogging the screen opening holes and preventing uniform charging, resulting in vertical stripes of white spots on one image. Smearing, etc. may occur. In addition, the screen is placed close to the photoconductor.
Although the effect is fully exhibited when a high voltage of ~3 KV is applied to the screen, such a setting promotes toner contamination of the screen.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the conventional art, it is an object of the present invention to provide a photoreceptor having a novel configuration and an image forming apparatus that uses this photoreceptor and can provide stable and clear images over a long period of time.

[Key points of the invention]

In order to achieve the above object, the present invention provides a photosensitive material in which electrode portions and insulating portions are alternately arranged in a band shape on an insulating support in a direction perpendicular to the charging progress direction, and a photoconductor layer is further provided on the a-layer. A primary charge of a predetermined polarity is applied to the photoconductor, which has a first electrostatic latent image or a first developed image formed thereon by exposure, development, etc. When performing secondary charging, a corona discharger is used, which has a corona ion flow control screen that applies a bias of the same polarity as the secondary charging polarity at or near the opening for irradiating corona ions. The present invention is characterized in that a bias having a polarity opposite to that applied to the corona ion flow control screen is applied to the electrode portion in the charging region.

[Embodiments of the invention]

The embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 is a sectional view of an image forming apparatus showing an embodiment of the present invention. The photoreceptor 1 is rotatably supported in the direction of the arrow shown in the figure, and a primary charger 2.
Secondary charger 3. Developing devices 4, 5. Polarity matcher6. Transfer device 7
1 Separator 8°Cleaner 9. Erasers 10 are sequentially arranged.

The photoreceptor 1 has an electrode IC and an insulating layer 1b alternately formed in strips on an insulating support 1d in a direction perpendicular to the direction of movement of the photoreceptor 1, and a photoreceptor layer having a bipolar intensity on top of the electrode IC and an insulating layer 1b. 1
a are laminated (see FIGS. 3 and 4). In addition,
The arrow shown in FIG. 4 is the moving direction of the photoreceptor 1.

The insulating support can be made of polyester or other resin film in the form of a sheet or belt, a cylindrical resin or gold paint surface coated with synthetic resin, or a heat-shrinkable tube used to insulate a cylindrical metal surface. A layered material is used. A photoresist is applied onto such an insulating support, exposed to light using a band-shaped mask, and then developed to form a band-shaped insulating layer. Next, a conductive resin in which colloidal silver is dispersed is applied to the groove between the insulating layers to form a band-shaped electrode portion.

In this way, electrode portions and insulating portions are alternately formed in a band shape on the insulating support. Further, a photoreceptor is obtained by applying a photosensitive layer thereon by a dipping method or depositing a photosensitive layer by ion sputtering or the like.

In addition to this, there is also a method of forming band-shaped electrodes and an insulating layer directly on an insulating support using means such as screen printing, and a method of forming an A1. Ag.

There is a method in which a metal such as Pb or Au is vapor-deposited in a band shape, and a photosensitive layer is coated or vapor-deposited thereon.

The size of each component of the photoreceptor 1 is set as appropriate. For example, the thickness of the insulating support 1d is 50 to 500 μm, the thickness of the electrode portion IC is 1 to 100 μm, and the width of the electrode portion IC is 1 μm. ~
The thickness of the photosensitive layer 1a is 5 to 100 μm.

Further, as shown in FIG. 1, the photoreceptor 1 has no photosensitive layer 1a formed at one end, and the strip-shaped electrode portion IC and the insulating portion 1b are exposed. A conductive grounding member 23 extending in the same direction as in contact with the strip-shaped electrode portion IC is disposed in this exposed portion.

The grounding member 23 is directly grounded. However, in the secondary charging area facing the screen 20 of the secondary charger 3, the grounding member 23 is removed, and instead, another conductive biasing member 24 is in contact therewith. Bias member 2
4 is grounded via a bias power supply 25. In other words, a bias voltage is applied by the bias power supply 25 via the bias member 24 to a portion of the band-shaped electrode portion IC corresponding to the secondary charging region, and the other region is grounded and has an potential of OV.

Further, the secondary charger 3 includes a conductive shield 3a, a corona wire 3b, a screen 20 for controlling corona ion flow. Power supply for generating corona ions 21. Screen bias power supply 2
Consists of 2. The corona ion irradiation opening of the shield 3a has a width of 20 to 30**, and the corona wire 3b is a tungsten wire with a wire diameter of 50 to 80 μm or a gold-plated tungsten wire. As shown in the cross-sectional view of FIG. 6(a), the screen 20 includes an insulator portion 20b5 and a conductor portion 20a from the corona wire 3b side, and the conductor portion 20a is connected to a bias power source 22. As the screen 20, a metal plate with a large number of holes formed by etching, electroplating, etc., coated with a resin on one side, or a metal mesh coated with a resin on one side are used. In this embodiment, the screen 20 and the shield 3a
The distance between the screen 20 and the photoreceptor 1 is set to 2, and the distance between the corona wire 3b and the photoreceptor 1 is set to 91.

Next, the operation in the above configuration will be explained.

Here, a two-color image forming process will be described with reference to the photoreceptor surface potential change diagram shown in FIG.

First, the surface of the photoreceptor 1 is uniformly charged to a predetermined polarity, for example, negative polarity, by the primary charger 2 (FIG. 5(a)). Next, two colors are applied to form a red part R and a black part B on the white background part W. Manuscript O
The document table 16 on which R is placed is moved and illuminated by the light source 11 for first exposure.

The reflected light from the original OR is transmitted through a plurality of mirrors and lenses 13.
and is exposed onto the photoreceptor 1 through the red filter 14.

As mentioned above, since the electrode IC of the photoreceptor 1 in areas other than the secondary charging area is grounded via the grounding member 23, an angry light layer is laminated on a normal grounded uniform conductive layer. As in the case of using a photoconductor, the red-corresponding area and the white-corresponding area on the photoconductor 1 are attenuated by light and the surface potential decreases, and the first electrostatic latent remains in the form where only the black-corresponding area remains charged. An image is formed (Figure 5, mountain).

Next, the surface of the photoreceptor 1 is charged by a secondary charger 3 to a polarity opposite to that of the primary charge. The polarity of the red-corresponding area and the white-corresponding area on the photoconductor 1 is reversed and the area is positively charged, but since the black-corresponding area was originally charged to a negative high potential, its surface is charged with a positive secondary charge. The potential decreases to approximately 1 of the initial level (FIG. 5(C)).

The effects of the screen 2o during secondary charging are as follows. That is, when a voltage of, for example, about 5 to 6 KV is applied to the corona wire 3b from the corona generation power source 21, positive corona ions generated thereby cause the corona wire 3b side of the screen 2o, that is, the insulator portion 2
The surface of 0b is positively charged.

At this time, since the conductor portion 20a of the screen 2o is grounded via the screen bias power source 22, lines of electric force are generated in the gap portion of the screen 31 as shown by broken line arrows in Fig. 6 (al).

The positive corona ions 26 of 11Vi are accelerated along the direction of the generated electric lines of force, and proceed at high speed toward the photoreceptor 1 from the normal direction thereof, as shown in FIG. 6 (bl).

Therefore, irrespective of the magnitude of the potential on the surface of the photoreceptor 1 caused by the first electrostatic latent image already formed on the photoreceptor 1, the positive corona ions 26 travel straight. The entire structure can be uniformly shifted to the positive side while maintaining the contrast of the formed potential.

Furthermore, in this embodiment, in the secondary charging region, a voltage of about -100 OV, which is opposite in polarity to the secondary charging polarity, is applied by the bias power supply 25 to the electrode portion 1c of the photoreceptor 1 via the biasing member 24. Since the effect of accelerating the secondary charged positive corona ions passing through the screen 20 toward the photoconductor 1 side is obtained, the bias voltage applied to the screen 20 is a low voltage of about 1°O to 100OV, and the bias voltage applied to the screen 20 is a low voltage of about 1°O to 100OV. A sufficient effect can be obtained by setting the distance from the surface of the body 1 to about 2 to 5 u. In this state, toner contamination of the screen 20 due to particles of scattered toner and the like is extremely small, and uniform and good secondary charging is performed even on thousands to tens of thousands of sheets.

After the secondary charging is completed, the light from the light source 12 for second exposure is applied to the document OR.
The reflected light is exposed again through a mirror, a lens 13, and a cyan filter 15. Then, the light attenuates in the area corresponding to the white background, and a second electrostatic latent image is formed on the photoconductor 1 with positive charges remaining only in the area corresponding to the red background (Fig. 5(d)
)).

Thereafter, the positively charged black toner BT is applied to the negative latent image corresponding to the black area on the photoreceptor 1 by the developing units 4 and 5.

A two-color toner image is formed on the photoreceptor 1 by attaching negatively charged red toner RT to the pressure latent image corresponding to the red portion (FIG. 5(e)).

Next, after the polarities of the two-color toner images on the photoreceptor 1 are aligned by a polarity matcher 6, the two-color toner images are transferred all at once onto a transfer paper 18 fed from a paper feed roll 17 by a transfer device 7. Further, the transfer paper 18 is separated from the photoreceptor 1 by the separator 8, sent to a fixing section (not shown) via a conveyance section 19, and after being fixed, becomes a final two-color image. Further, the toner remaining on the photoconductor 1 is removed by a cleaner 9, and the charge remaining on the photoconductor 1 is erased by an eraser 10, and the toner remaining on the photoconductor 1 is removed by an eraser 10.
It is then ready for the next image formation.

Note that since the strip-shaped electrode portion 1c of the photoreceptor 1 is grounded in processes other than secondary charging, the setting voltage of the developing device, transfer device, etc. is applied to the photosensitive layer on a normal grounded uniform conductive layer. This is the same as when using a photoreceptor with laminated layers, and there is no need to make any particular changes.

[5 Benefits] As explained in detail above, the photoreceptor of the present invention has a novel configuration, and the image forming apparatus of the present invention using this photoreceptor can be uniformly charged over a long period of time. This allows you to obtain stable and clear images.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a photoreceptor of the invention, and FIG. 2 is a sectional view showing an embodiment of an image forming apparatus of the invention. FIGS. 3 and 4 are a sectional view and a perspective view of the main parts of the photoreceptor of the present invention, respectively, FIG. It is a sectional view for explaining a screen effect. 1... Photoreceptor, la... Photosensitive layer. 1b... Insulating part r lc... Electrode part. 1d... Insulating support, 3 ...Secondary charger, 4, 5...Developer, 20...Screen, 23...Grounding member. 24...Bias member. Patent applicant Casio Computer Co., Ltd. Same as above
ID Co., Ltd. Representative Patent Attorney Yoshiyuki Osuga Figure 3 Figure 4

Claims (2)

[Claims] (1) A photoreceptor in which electrode portions and insulating portions are alternately arranged in strips on an insulating support, and a photoconductor layer is further laminated thereon. (2) Using a photoreceptor in which electrode portions and insulating portions are alternately arranged in strips on an insulating support in a direction perpendicular to the charging progress direction, and a photoconductor layer is further laminated thereon, a primary polarity of a predetermined polarity is used. When performing secondary charging with a polarity opposite to the primary charging on the photoreceptor on which a first electrostatic latent image or a first developed image has been formed by imagewise exposure, development, etc., corona ions are charged. Using a corona discharger in which a corona ion flow control screen to which a bias of the same polarity as the secondary charging polarity is applied is arranged at or near the irradiation opening, the radiation is applied to the electrode portion in the secondary charging area on the photoreceptor. An image forming apparatus characterized in that a bias having a polarity opposite to that applied to a corona ion flow control screen is applied.