JPS59100469A - Picture forming method - Google Patents

Abstract

PURPOSE:To put an original image and a picture formed by laser light scanning together by carrying out an image forming process by positive exposure and an image forming process by negative exposure in combination. CONSTITUTION:The photosensitive body 1 consisting of a conductive layer 1A, photoconductive layer 1B, and insulating layer 1C is passed through an electrophotographic process in the order of uniform electrostatic charge, original image exposure consisting of a dark part D and a light part L, simultaneous destaticization, and uniform exposure. An electrostatic image of the dark part D is formed on the light part L having a zero potential as the background, so this image is developed. Then, the photosensitive body 1 after the development is passed through the 2nd electrophotographic process in the order of uniform charge, destaticization, and exposure by laser light I. The potential of a part irradiated with the laser light I rises and an unirradiated part NI is still at the zero potential. This 2nd electrostatic image is developed with toner to obtain a composite picture. A developing means does not contact a photosensitive drum surface so as to prevent the 1st toner image from being destroyed.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to, for example, an electrophotographic image corresponding to an image of a document, and an electrophotographic image corresponding to an optical image written based on an image signal. ``D-shaped image forming method.''

[Sakura] Technical background and problems] □This type of image forming method (e.g., N's analog image (based on the image of N draft) and digital image using laser, LED, etc. (based on image signal) It is applied when all images are formed using the same device, and is an indispensable technology for creating multi-functional image forming devices by adding printer functions to copiers and editing functions. It is.

However, the Carlson process conventionally applied to copying machines forms a positive latent image, whereas the latent image is created by writing an optical image based on an image signal with a laser or an ED''h. The full formation process is to completely form a negative latent image.Therefore, if both processes are to be completely superimposed to form an image, a separate development process is required, and there were various problems in realizing this. In addition, in order to solve this problem, in the process of writing a light image based on an image signal to form the entire latent image, a positive latent image is created by irradiating light and sound corresponding to the areas where there is no image signal. However, in such a process, the writing process of the optical image becomes complicated, and the electric potential of the area irradiated with the optical sound cannot be completely erased unless it is done with high precision. This results in a new problem of fogging.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and it is possible to form an electrophotographic image with the same polarity in the unirradiated portion of light during image exposure and the irradiated portion of light corresponding to the image, and as a result, it is possible to form an electrophotographic image with the same polarity. It is an object of the present invention to provide an image forming method that can completely visualize an electrophotographic image using a developing means and can contribute to multifunctionalization of an image forming apparatus.

[Summary of the invention]

In order to achieve the above object, the present invention provides a first polarity with respect to a reference potential for an image carrier comprising a laminated photoconductive layer and an insulating layer that transmits a part of the spectral wavelength of the photoconductive layer. a first electrophotographic image forming step in which an electrophotographic image is formed with a first polarity by charging the image carrier, exposing the image carrier to remove the charge from the outside to near a reference potential, and further exposing the entire surface to light with a first polarity;
charging the image carrier with a first polarity with respect to a reference potential, and then discharging the image carrier to near the reference potential;
The apparatus further includes a second electrophotographic image forming step of irradiating the image carrier with light corresponding to the image and forming an electrophotographic image with the polarity of the nest 1 on the irradiated part of the light. .゛ - [Embodiments of the Invention] An embodiment of the present invention will be described below with reference to all the drawings.

FIG. 1 is a schematic sectional view showing the structure of an image carrier. The image carrier 1 includes a conductive substrate 1A made of aluminum or the like, a bipolar photoconductive layer 1B (for example, a zinc oxide layer sensitized with rose bengal and 27 mm thick), and an insulating layer 1C (for example, a 20 mm thick zinc oxide layer).
It is formed by laminating layers of polyethylene terephthalate (V-) with a thickness of .mu.m. The photoconductive layer 1B is also made of, for example, St.

5eTt”, ApzSe3, a-5i, Cd
Inorganic photoconductive materials represented by S, pvx, pvx=r
It can be formed from an organic photoconductive material such as yy.

The insulating layer 1C may be made of an insulating material that can transmit two parts of the spectral fatigue of the photoconductive layer 1B. In the image carrier 1 having such an outer two-layer structure, an electrophotographic image, for example, a latent image, is formed by contrast due to a difference in surface potential.The surface potential of such an image carrier 1 is shown in FIG. As shown, the □ capacitance of the insulating layer 1C is Cz
CFZα2) The capacitance of the photoconductive layer 1B is C1(F/
am 2), the surface charge is Qz C
C/an 2), the charge on the bottom surface of the insulating layer 1C is QI C
C/1m2. ”) (in this case, the electric charge within the conductive substrate 1A becomes -QzQzh), generally Vz is expressed by the first equation.

A first electrophotographic image forming step will be described in which an electrophotographic image is formed with a first polarity by charging with a polarity, removing the charge to near a reference potential while exposing the entire image of the image carrier, and further exposing the entire surface with light. Figure 6 (α), ′<i>, <c>
3(d) is an explanatory diagram of the movement of charge in the first electrophotographic image forming step, and FIG. 3(d) is an explanatory diagram of the change in surface potential in the first electrophotographic image forming step.

First, the image carrier 1 is charged with the first right polarity with respect to the reference potential. For example, 500~I DO"'OLu, x-'se'
In the bright place of c, 0.5 (μq/an
") is positively charged using the charger 6 which passes a current. As a result, as shown in FIG. sexual layer 1B
As a result of the low resistance, the same amount of negative charge as the bald charge is applied to the lower surface of the insulating layer 5.The surface potential of the image carrier 1 is 13.00V.
(Vt in FIG. 3(d)). Note that this step is not limited to charging in a bright place, and it is also possible to expose the entire surface of the image bearing member in advance and perform charging while it has sustained conductivity. In particular, if this method is used, charging and exposure do not need to be performed at the same time, so strict tie and mink matching is not required when carrying out this process. Eliminates static electricity in the vicinity. For example, the image carrier and carrier 1 are
is image-exposed, and the dark area (the original unexposed area due to image exposure, which corresponds to the image of the original), P, dark area, and light area (
The surface potential of both L and L is near zero, for example -i,
The static eliminator 2 removes static electricity (this is static elimination due to negative charges) so that oov (Fig. 6 (d) K oyu V2). Then, as shown in FIG. 3<h>, the insulating layer 1
On the surface of C and the bottom surface of the insulating layer 1C, a considerable number of positive charges and a larger number of negative charges remain in the dark part, a small number of negative charges and the same amount of positive charges remain in the light part, and a large number of positive charges remain in the light part. The surface potential in both the dark and dark areas is -1 (30V' (Vz in FIG. 6(d)). This is because in the dark areas, the insulating layer 1C The amount of negative charge on the photoconductive layer 1B is small, and conversely in the light part, as the positive charge on the insulating layer 1C is neutralized by the negative charge (due to static elimination), the resistance of the photoconductive layer 1B becomes lower. Negative charges freely escape to the conductive substrate 1A, and as a result, more negative charges exist in the insulating layer 1C than in the dark area.
This is because you will be on top of it.

Next, in order to expose the entire surface of the image carrier 1, for example,
When the entire surface is exposed with 1000Ltbx-se11', an electrophotographic image is formed with the first polarity in the original unirradiated area (i.e., dark area) in the image exposure. In other words, as shown in FIG. 6(C). Then, the same amount of charge with the opposite polarity as the charge on the surface of the insulating layer 1C remains on the bottom surface of the insulating layer 10, and the surface potential of the dark part becomes 500V (V3' in FIG. 6(d)).
Then, the surface potential of the light part becomes 1100 V (V4 in FIG. 6(d)), and an electrophotographic image is formed by the contrast due to the difference in surface potential between the two parts.

Next, the image carrier is charged with a first polarity with respect to the reference potential, and the subsequent image carriers are charged to near the reference potential;
First, we will explain the second electrophotographic image forming process in which an element corresponding to the image □ is irradiated onto the image carrier, and an electron true image is entirely formed with the first polarity mainly on the irradiated portion of this element. do. Figure 4 (α), ψ).

iC) is an explanatory diagram of the movement of charge in the second electrophotographic image forming step, and FIG.

First, the image carrier is charged with a first polarity corresponding to the entire image exposure position. For example, in a bright place with 500 to 1000L1LjC-evening ec, 1.5 (μq/cyn") for zero potential □
The charger 16 that passes the current is then positively charged. As a result, as shown in FIG. 4 (α), the surface curve of the insulating layer 1C has a positive charge that is a multiplier. As a result of this process, positive charges and negative charges gather on the lower surface of the insulating layer, and the surface of the image carrier 10 becomes i g'o'o V"c as shown in FIG. ”
It should be noted that the charging process is not limited to charging in a bright place, but it is also possible to carry out the entire charging process while the entire carrier is exposed in advance and has sustained conductivity. It's possible. In particular, since charging and exposing do not need to be performed simultaneously in this way, strict timing matching is not required when carrying out this process.

Then, the charge is removed to near the reference potential of the entire image carrier.

For example, the static eliminator 2 performs negative charging to eliminate static electricity.

The result of 'ko' is shown in Figure 4' (h).
') , E * riI i''-Ichiiyo4゜1tsuiyo LC.

Therefore, the surface potential of the image carrier 1 becomes 1100 V (vz in FIG. 4(d)). ' □Next, light 1 corresponding to the □-image is irradiated onto the image carrier C. For example, the entire laser beam image is written based on the image signal 1. Then,
As shown in Fig. 4(-), there is no charge corporation in the original unirradiated area NZ, and in the illuminated area I, the original conductive layer 1B has low resistance. Unfortunately, the same amount of negative charge with the opposite polarity as that of the insulating layer 1C remains on the lower surface of the edge layer 1. As a result, the surface electric wire of the irradiated part I is 500V (see Fig. 4). d) The surface potential of the unirradiated part Nl becomes 1100 V (V4 in Fig. 4(d)) at K and Vl),
An electrophotographic image is formed due to the contrast caused by the difference in surface potential between the two.

In the afternoon, electronic photos of the 1st and 2nd Sasa! Description of the static eliminator used in the forming process It is desirable that the static eliminator be highly effective in keeping the surface level of the image bearing member constant. As is clear from the explanatory power mentioned above (
Figure 3 (d), Figure 4 (d)
This is because a surface potential must be created.
.

Figure 5 is a schematic diagram showing the configuration of the static eliminator.
'KVt7) An AC voltage power source 11'5 near 7-9 is applied to the shield 13, and a DC voltage power source 14 is applied to the shield 13.

Note that the structure of the static eliminator can be other than the above, as shown in FIG. 6 or 7A. It is also possible to configure The one shown in Figure 6 is a high voltage DC
When the power source 20 is applied to the wire 21, the polarity of the applied voltage is positive, the polarity is positive when removing charges, the positive potential is used when removing negative charges, and the polarity of the applied voltage is positive. is the ground, and is configured so that the surface potential is stabilized by the voltage value applied to the grid 2 by the low-voltage DC power source 26. is shield case 60
is the ground, and the charge wire 61 is connected to the AC power source 2.
and a DC power supply 63 to apply high voltage S,
It is configured so that the stable point of the surface potential can be changed freely depending on the voltage and polarity of the DC power supply.
ru0,.

Next, an example of the first and second electronic image forming devices and a complete image forming apparatus will be described with reference to FIG. 8. The heat treatment device includes a drum-shaped image carrier 1 rotatably installed approximately in the center of the main body, and a charger (a tungsten lamp/lamp for exposure and a charge wire gold bias for charging) 6 for performing brightness and household type. and a static eliminator 2 shown in FIG. 5, and an image exposure unit 44 that irradiates a document placed on a document table 42 at a ratio of 1:51 from a lamp 43 and performs image exposure using the reflected light.
Based on the image signal, irradiate V-za light to write an optical image,
an optical image writing section 45, a full-surface exposure lamp 46 for full-surface exposure, and a developing means for visualizing the electrophotographic image formed on the image carrier 1, such as a developer on the electrophotographic image. a developing device 47 for developing the image, a paper feeding section 4.8 that sequentially supplies sheets of paper one by one toward the curved portion of the image carrier 1; A developer on the image carrier 1 (developing device 4.
A transfer charger 49 transfers the electrophotographic image (attached to the electrophotographic image by 7), a peeling section 50 peels the developed paper from the image carrier 1, and fixes the developer on the peeled paper to the paper. It is composed of a fixing device 51, a paper tray 52 for ejecting the fixed paper, a cleaning section 53 for cleaning developer remaining on the image carrier 1 after transfer, and a main motor 54. There is.

The first electrophotographic image forming step in such an apparatus is
As shown in the timing chart of FIG. 9(α), the image carrier 1 is photopic charged by the charger 6, and then the image carrier 1' is exposed to the image exposure section 44 using the emitted light from the paper. f,
During image exposure, the charge is removed by the static eliminator, and the entire surface of the image carrier 1 is further exposed to light by the full surface exposure lamp 46.

Through this step, as explained in Fig. 6(a) to (d), the surface potential of the dark part is 500V (V3 in Fig. 6(d)), and the surface potential of the light part is 1100V (
V4) in FIG. 6(d), and an electrophotographic image is formed by the contrast due to the difference in surface potential between the two. Further, in the second electrophotographic image forming step in such an apparatus, as shown in the timing chart of FIG. The charge is removed by the optical image writing section 4.
5, a laser beam based on the image signal is irradiated to write an optical image.
As explained in ~(!t), γ (the surface potential of the irradiated part I is 50
At 0V (Vs in Figure 4(d)), the unirradiated area NZ
The surface potential force L-1c+'ov' (, V4 in FIG. 4(d)) is obtained, and an electrophotographic image is formed by the contrast due to the difference in surface potential between the two.

In this apparatus, when the second electrophotographic image forming step is performed in full after the first electrophotographic image forming step, the electrophotographic image is formed by the first electrophotographic image forming step. After being formed, the entire electrophotographic image is first developed in the developing device 47. Thereafter, the image carrier 1 rotates in the counterclockwise direction as shown in FIG. The transfer charger 49 and cleaning section 56 are not operated. Then, the second electrophotographic image forming step is repeated on the image carrier 1 that has rotated once, and a new electrophotographic image is formed on the image carrier 1 on which the visualized electrophotographic image has been formed. Form. The same applies to the case where the second electrophotographic image forming step is performed first.

The electrophotographic image newly formed in this way is developed by the developing device 47. When developing at this time, the first developed electrophotograph 1
In order to prevent the image from being destroyed, the developing device 47 is arranged in a non-contact manner with the image carrier 1.

The developer attached to both electrophotographic images is transferred onto the paper by the transfer charger 49, and the paper is discharged to the paper discharge ton 5'2 via the fixing device 51. An image corresponding to the original image and an image corresponding to the optical image written based on the image signal are formed on the ejected paper.

Note that the above-mentioned embodiment is merely an example, and various modifications can be made within the scope of the gist of the present invention. For example, the first polarity and the 29th polarity do not need to be so-called opposite polarities (positive, negative), but may be two types of levels that fall within a range above and below an arbitrary reference potential. Also, depending on the nature of the image carrier,
It is also possible to carry out the process by applying the surface potential described above.

〔Effect of the invention〕

As is clear from the above description, in the image forming method of the present invention, it is possible to form an electrophotographic image on the unirradiated portion of light during image exposure and the irradiated portion of light corresponding to the image, and as a result, It has excellent effects such as being able to visualize an electrophotographic image with a single developing means and contributing to multifunctionalization of an image forming apparatus.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing the structure of the image carrier, FIG. 2 is an explanatory diagram of the surface potential of the image carrier, and FIG. 3(a). (b) and (C) are explanatory diagrams of the movement of charges in the first electrophotographic image formation process, and FIG. 6(d) is an explanatory diagram of the change in surface potential during the first electrophotographic image formation process. , FIG. 4(α), (h), and (C) are explanatory diagrams of charge movement in the second electrophotographic image forming step, and FIG. 4(d) is a surface diagram in the second electrophotographic image forming step. Explanation about changes in potential - 1 Figure 5 is an explanatory diagram showing an example of a static eliminator, Figures 6 and 7 are explanatory diagrams of other static eliminators, and Figure 8 is an explanatory diagram of the first and second electrophotographs. A schematic sectional view showing an example of an image forming apparatus equipped with an image forming process, FIG.
Timing of the electrophotographic image forming process...Image bearing body, 1
A... Conductive substrate, 1B... Photoconductive layer, 1C...
- Insulating layer, 47... Visualizing means. \A (a) , (b) '(C)・
'(d)

Claims (7)

[Claims] (1) An image carrier formed by laminating a photoconductive layer and an insulating layer that transmits a part of the spectral wavelength of the photoconductive layer is charged with a first polarity with respect to a reference potential, and the image carrier is charged with a first polarity with respect to a reference potential. A first electrophotographic image forming step of forming an electrophotographic image with a first polarity by removing static electricity to near a reference potential during image exposure and then performing full-surface exposure; The image carrier is charged with a polarity of 1, then the charge is removed from the image carrier to near the reference potential, and the image carrier is further irradiated with light corresponding to the image. and an electrophotographic imaging step of forming an image. (2) The image forming method according to claim 1, wherein the step of charging the image carrier with the first polarity in the first electrophotographic image forming step is a step of charging in a bright place. (3) In the first electrophotographic image forming step, the step of charging the image carrier with the first polarity is performed while the image carrier is exposed in advance and the photoconductive layer has sustained conductivity. The image forming method according to claim 1, which is a step of charging. (4) The image forming method according to claim 1, wherein the step of charging the image carrier with the first polarity in the second electrophotographic image forming step is a step of charging in a bright place. (5) In the second electrophotographic image forming step, the step of charging the image carrier with the first polarity involves exposing the image carrier to light so that the photoconductive layer has sustained conductivity. The image forming method according to claim 1, which is a step of charging. (6) The first electrophotographic image forming step is performed by overlapping the electrophotographic image formed by the second electrophotographic image forming step after the electrophotographic image formed by the second electrophotographic image forming step is visualized. Image forming method described in section. (7) The second electrophotographic image forming step is performed by overlapping the electrophotographic image formed in the first electrophotographic image forming step after the electrophotographic image formed in the first electrophotographic image forming step is visualized. ,
9 image forming methods. (8) An image forming method according to claim 6 or 7, wherein the electronic image formation is performed by a developing means disposed not in contact with the image carrier. :