JPS6252865B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic copying method, and more particularly to an electrophotographic copying method in which a large number of copies are continuously made by exposing a photoreceptor to a photoreceptor once. Compared to printing technology, electrophotographic copying technology has the advantage of being able to directly create copies of manuscripts such as books without making plates, but it is difficult to continuously produce multiple copies from a single manuscript. In this case, the exposure of the image from the original onto the photoreceptor must be repeated for each copy, which has the disadvantage that the copying speed cannot be increased as with a printing machine. On the other hand, in order to avoid the complexity of the plate-making process in printing technology, printing apparatuses have been proposed in which plate-making is performed by electrophotography. For example, as described in Japanese Patent Publication No. 46-4611, an electrophotographic copying device and a printing machine are combined, an original plate is made by the electrophotographic copying device, and this is automatically mounted on the plate cylinder of the printing machine. An electrostatic latent image corresponding to the original is formed on the surface of a photoreceptor drum that can be moved into and out of contact with the plate cylinder, such as in a printing device or an improved version of this described in Japanese Patent Publication No. 55-12596. A device has been proposed in which this electrostatic latent image is transferred to a master paper mounted on a plate cylinder, developed, and then etched to form a master plate, which is then inked and printed. . Although these devices only need to create an image from a document once, they require an electrophotographic copying device and a printing device, which makes the entire device large and expensive. Another method of printing using only electrophotographic technology is to charge a photosensitive plate, imagewise expose it to form an electrostatic latent image, and then attach the photosensitive plate to a rotating drum to form an electrostatic latent image. The original plate is developed and fixed to form an original plate, this original plate is charged and exposed uniformly, and this is developed to transfer the unmelted toner from the original plate to copy paper to form a duplicate.After making a large number of copies, the original plate is The U.S. Patent No.
It is proposed by the specification of No. 3615128. However, in this case, like the above-mentioned device, one photosensitive plate is required for each original, and since one photosensitive plate cannot be reused, the cost of copying increases when the number of copies is small. There was a problem. The present invention was made in order to solve the problems in this type of electrophotographic copying method, and it is possible to manufacture the device to the same size as a conventional single-image exposure, single-sheet copying type electrophotographic copying device. It is an object of the present invention to provide an electrophotographic copying method that can reuse a photoreceptor and economically make a large number of copies in succession. The electrophotographic copying method according to the present invention includes: (a) forming an electrostatic latent image on the surface of an amorphous silicon photoreceptor, developing the electrostatic latent image with a powder developer to form a powder image; (b) charging the surface of the photoreceptor on which the original image was created and uniformly exposing the photoreceptor surface to form an electrostatic latent image on the original image; and (c) creating a copy, in which the image is developed with a powder developer, an unfixed powder image is layered on the original image, and the unfixed powder image is transferred and fixed onto a transfer paper, and (c) the copy is created. After repeating the process, the original image on the surface of the photoreceptor is removed with a metal blade. It is completed by developing the body. The amorphous silicon photoreceptor (hereinafter referred to as a-Si photoreceptor) used in the method of the present invention is mainly composed of amorphous silicon, contains oxygen and hydrogen, and optionally contains group B elements or group B elements. It means a photoconductive layer containing a Vb group element formed directly on a conductive substrate or via an intermediate layer made of a cadmium sulfide-based, zinc selenide-based, or As ₂ Se ₃ -based photoconductive material. . When the photoconductive layer is formed directly on an electrically conductive substrate, it is suitable that the photoconductive layer contains a group b element, preferably boron, in addition to oxygen and hydrogen. This is because it is difficult to obtain a dark resistance of 10 ¹³ Ω·cm or more, which is the minimum required for forming an electrostatic latent image, only by containing oxygen and hydrogen. In this case, the contents of oxygen and hydrogen contained in the photoconductive layer are each approximately 10 ^-6
5 x 10 ^-2 atomic percent and about 10 to 40 atomic percent, and boron about 10 to 40 atomic percent.
It is desirable to contain 20,000 ppm. This is because oxygen affects the dark resistance, photosensitivity, heat resistance, durability, etc. of the photoconductive layer, and if it is less than 10 ^-6 atomic percent, no effect can be expected ^; If it exceeds, depending on the hydrogen content,
Even if the dark resistance improves, the photosensitivity decreases significantly, so it is preferable to set it within the above range. In addition, the inclusion of hydrogen can be efficiently carried out by using it as a carrier gas for SiH ₄ gas, which is a raw material for a-Si. In addition, as the boron content increases, the dark resistance improves, but if it is less than 10 ppm, it is not possible to improve the dark resistance to 10 ¹³ Ω・cm or more, and if it exceeds 20,000 ppm, the dark resistance decreases. However, the required dark resistance cannot be obtained. When an intermediate layer consisting of a cadmium sulfide-based or zinc selenide-based photoconductive material and a binder or an intermediate layer consisting of an As ₂ Se ₃ -based photoconductive material is provided between the photoconductive layer and the conductive substrate, oxygen and hydrogen It is possible to obtain the required dark resistance simply by containing , and electrical conductivity can be controlled by adding Group B elements and Group Vb elements as valence control agents. That is, a photoconductive layer made of amorphous silicon (a-Si) containing hydrogen and oxygen exhibits weak n-type semiconductor properties, but a trivalent active layer such as a group B element, preferably boron, as an acceptor impurity. The dark resistance can be further improved by doping the center and compensating for the n-type semiconductor characteristics, and by adding a Vb group element, preferably phosphorus, as a donor-type impurity, the p-type semiconductor characteristics can be imparted. can. In the latter case, the dark resistance of the photoconductive layer itself slightly decreases due to the addition of group Vb elements, but the intervening intermediate layer prevents the escape of charges, so the overall dark resistance of the photoconductive layer itself decreases. If the dark resistance is 10 ¹¹ Ω・cm or more
A value of 10 ¹³ Ω・cm or higher is guaranteed. In addition, the dark resistance of the photoconductive layer itself, which is made of a-Si containing only oxygen and hydrogen, has been improved to about 10 ¹² Ωcm, so it is 10 ¹³ regardless of the presence or absence of group B elements and Vb group elements. A dark resistance of Ω·cm or more can be obtained as a whole, and the photoreceptor used in the method of the present invention can be manufactured. However, when these valence control agents are included, the concentration of group B elements is 20,000 ppm or less,
The content of Vb group elements is preferably 1000 ppm or less. This is because if the valence control agent is contained more than that, the dark resistance of the photoconductive layer itself decreases to 10 ¹¹ Ω·cm or less. Note that when an intermediate layer is included, the oxygen content range is expanded from 5 x 10 ^-2 to 1 x 10 ^-5 in the case of no intermediate layer to 5 x 10 ^-2 to 10 ^-6 atomic percent. be able to. The photoconductor layer can be formed by a glow discharge decomposition method or a sputtering method, but it is preferable to use a glow discharge decomposition method, which facilitates the inclusion of hydrogen and oxygen. This photoconductor layer is formed to a thickness of 10 to 60 microns, but can be reduced to a thickness of 0.5 microns when forming an intermediate layer. Therefore, when a photoconductive layer is formed by the glow discharge decomposition method, the formation rate is slow at 10 to 2500 Å/min, but the formation time can be shortened by providing an intermediate layer. As is clear from the above, the intermediate layer increases the charging potential on the surface of the photoconductor layer and itself plays the role of ensuring the passage of photocharge carriers, and is made of cadmium sulfide or zinc selenide. A photoconductive material is kneaded with a resin binder and coated onto a substrate to form an intermediate layer, or an As ₂ Se ₃ based photoconductive material is formed on a substrate by vacuum evaporation to form an intermediate layer. It is preferable that Also, its thickness is approximately
10 to 70μ is sufficient. This cadmium sulfide-based photoconductive material includes CdS, CdS・nCdCO ₃
(0<n≦4), CdS-CdSe or copper,
Examples include those doped with 0.01 to 5% by weight of a metal activator such as silver. Furthermore, as the zinc selenide-based photoconductive material, not only ZnSe but also ZnSe doped with a metal activator can be used. The resin binder in which these photoconductive materials are dispersed does not decompose or dissolve even when heated at temperatures of 100 to 250°C, has high insulation resistance, and contains 10 to 70% by weight of the cadmium sulfide photoconductive materials. When the thickness of the intermediate layer is 10μ or more, the dark volume resistance increases.
Any material having a resistance of 10 ¹³ Ω·cm or more may be used, and specifically thermosetting resins such as acrylic resin, amide resin, epoxy resin, silicone resin, phenolic resin, and allyl resin are suitable. As the As ₂ Se ₃ based photoconductive material, not only As ₂ Se ₃ but also Te may be used in combination as necessary. As mentioned above, the photoconductive layer of the a-Si photoreceptor is formed of amorphous silicon containing at least oxygen and hydrogen, but this photoconductive layer is different from conventional selenium or cadmium sulfide resin photoconductive layers. The surface hardness is extremely high, reaching 1800 to 2300 Kg/mm ² (Bitzkers hardness Hv ₂₅ ), which is higher than aluminum's 18
~23 times as hard as stainless steel, and 9 to 11 times as hard as Sapphire, so it won't be damaged even when using metal plates, has excellent durability, and is more durable than conventional photoreceptors. The spectral sensitivity characteristics are significantly improved. In addition, a-Si itself is approximately 700℃
Even when an intermediate layer is provided, the intermediate layer is also stable up to about 250° C., so it is significantly superior in heat resistance to conventional photoreceptors. The present invention is carried out in the following manner using the a-Si photoreceptor described above. That is, first, the surface of the a-Si photoreceptor 1 is charged with a corona charger or other known charging means 2 (see FIG. 1a), and an image is exposed from the original 3 using the optical system to be deposited onto the photoreceptor 1. An electrostatic latent image is formed (see b in the same figure). Next, the electrostatic latent image on the photoreceptor is developed using a known powder developer to form a powder image (see FIG. 1c), and then subjected to appropriate means such as heat fixing, flash fixing, An original image 4' corresponding to the original is created by semi-fixing the image on the photoreceptor by pressure fixing or the like (d in the figure). It should be noted that semi-fixed is a level that does not transfer onto the transfer paper even when subjected to the action of a transfer charger described later, and can be easily removed when the metal blade 8 is brought into contact with the surface of the photoreceptor to cause relative displacement. It means a state where it is attached or fixed. For example, in the case of thermal fixing, the heating temperature is determined by the melting point of the powder image forming particles (toner) of the developer, but is usually 20 to 40 degrees Celsius lower than the fixing temperature for copy paper, which is 120 to 200 degrees Celsius, or 80 to 180 degrees Celsius. It is preferable to do so. Furthermore, since the base of the photoreceptor is metal,
Unlike transfer paper (or copy paper), the surface of the photoreceptor is cold and has a high heat absorption rate, so semi-fixing does not occur at very low temperatures. Therefore, it is practical to determine it by testing the developer used. After the original image creation process is completed as described above, the original image (corresponding to the original plate in printing) is charged (the first
(see Figure e), uniform exposure imparts an electric charge to the semi-fixed toner (see Figure f), and an electrostatic latent image is re-formed. Note that the charge on the semi-fixed toner 4 forming the original image remains as it is because the photoconductive layer of the photoreceptor under the toner is not photoexcited even if the entire original image is uniformly exposed due to the presence of the toner.
This electrostatic latent image is developed with a powder developer to layer an unfixed powder image made of unfixed toner 5 on the original image (Fig. 1g), and this unfixed powder image is transferred to a charger 6.
After the image is transferred onto a transfer paper (copy paper) 7 (h in the same figure), a copy is produced by fixing it by a conventional method. Since the original image 4' remains intact on the surface of the photoreceptor after transfer, Figure 1 e to Figure 1 h
By repeating the steps up to this point, a large number of continuous copies are made. After continuously copying a large number of sheets as described above, the metal blade 8 is brought into contact with the surface of the photoreceptor, and a relative displacement is generated between the two to remove the semi-fixed toner on the surface of the photoreceptor (see Figure 1 i). ), the photoreceptor is regenerated by uniformly exposing it to remove the residual potential (see j in the same figure), and it becomes possible to reuse it. As explained above, in the present invention, an original image is formed in advance on a photoreceptor by one image exposure from an original,
After successively creating a large number of copies from this original image, the photoreceptor can be recycled and reused, making it possible to use the same size as the conventional single-image exposure, single-copy type electrophotographic copying machine. The device allows economical continuous copying of multiple sheets. That is, according to the present invention, even in a copying machine with a movable document table, the number of times the document table moves is reduced, so wear and tear on the machine is suppressed, and it can be used as easily as a copying machine with a fixed document table. easy. The number of times the exposure lamp is lit is reduced, resulting in a longer lifespan and further power savings. Since the next original can be set while copying a large number of sheets, at least the time for exchanging originals can be shortened. After the electrostatic latent image is formed, the photoreceptor drum can be moved at high speed, so it can handle higher speeds. Excellent effects such as DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an electrophotographic copying apparatus used for carrying out the method of the present invention will be described below with reference to the accompanying drawings. FIG. 2 shows a schematic configuration of an electrophotographic copying machine for single-image exposure and multiple-sheet copying to which the method of the present invention is applied. Reference numeral D is an a-Si photoreceptor drum, around which is a corona charger 18 for charging and a slit 17 for exposure. , a uniform exposure light source 19, a developing device 20, a transfer charger 21, a separation charger 22, a semi-fixing device H,
Metal blade cleaner 23, eraser lamp 24
are arranged sequentially. Reference numeral 11 denotes a reciprocally movable document table on which a large number of documents to be copied are placed on a transparent glass plate 12. When copying using this device, first turn on the print switch (not shown) on the device.
The charging charger 18, the exposure lamp 13, and the scan solenoid SL1 of the document table 11 are turned on.
The document table 11 starts scanning to the right in the figure, and the document placed on the document table is exposed by the exposure lamp 13, and its image is projected by the first mirror 14, the projection lens 15, and the second mirror 16. Through the exposure slit 17, the latent image is sequentially projected onto the rotating photosensitive drum D, which is uniformly charged by the charging charger 18, and an electrostatic latent image corresponding to the original is formed on the photosensitive drum D. Due to the rotation of the photosensitive drum D, this electrostatic latent image passes through the light source 19 in the OFF state, and is then developed into a powder image by the developing device 20 which is constantly driven. pass through. At this time, the semi-fixing device H is turned on, and the powder image passing through it is transferred to the photoreceptor drum D.
It is semi-fixed on top to form the original image. After this semi-fixed powder image, that is, the original image passes through a cleaner 23 and an eraser lamp 24 having a metal blade 23' located apart from the photoreceptor surface, the entire surface of the photoreceptor is charged to maintain an on state. The battery is recharged by the charger 18. On the other hand, the exposure lamp 13 is turned off when the scanning movement of the document table 11 is completed, and at the same time, the uniform exposure lamp 19 is turned off.
is turned on, and the portions where the image does not have the electric charge applied by the subsequent charging charger 18 are erased, so that they are not developed by the developing device 20. That is, this uniform exposure lamp 19 functions as a rear end eraser. The photosensitive drum D, which has been more uniformly charged than the original image by the charging charger 18, has started its second rotation, and after passing through the exposure slit 17, it is uniformly exposed by the uniform exposure light source 19 which is in the on state. Only the charges in the areas where the original image does not exist are erased, and the charges remain only on the original image, forming an electrostatic latent image corresponding to the original image. This electrostatic latent image on the original image is turned into powder by the developing device 20, and the photosensitive drum D
An original image (that is, a semi-fixed powder image) and an unfixed powder image are formed overlappingly on the surface and move toward the transfer section. On the other hand, prior to this, seat cassette 2
The copy sheets P stacked and stored in 5 are
The sheets are fed out one by one by the paper feed roller 26 operated by the paper feed solenoid SL2, and then transferred to the conveyance roller 17.
As is well known, the image is sent to the transfer section in synchronization with the rotation of the photosensitive drum D. Immediately before the copy paper P reaches the transfer section, the transfer charger 21 and the separation charger 22 are turned on, and the unfixed powder image on the original image is transferred to the transfer charger 21.
The copy paper P having the transferred unfixed powder image is separated from the photosensitive drum D by the action of the separation charger 22, and then transferred to a pair of heat rollers by the conveyor belt 28. The powder image is conveyed to rollers 29, where it is fixed, and then discharged onto a tray 31 by discharge rollers 30. On the other hand, the photosensitive drum D holding the original image after transferring the unfixed powder image passes through the semi-fixing device H which is already turned off after one rotation from the start of semi-fixing.
Complete the first copy. Thereafter, the same operation is repeated from the second copy to a predetermined number of copies to obtain a predetermined number of copies on the tray 31. After the predetermined number of copies have been completed, that is, the final copy has been transferred, and just before the original image reaches the cleaner section, the solenoid SL3 is turned on, and the metal blade 23 of the cleaner comes into contact with the surface of the photoreceptor, removing the original image. At the same time, the eraser lamp 24 is turned on to completely erase the residual charges. Note that the solenoid SL3 is turned on only during one rotation of the photoreceptor drum D, and brings the metal blade 23 into contact with the metal blade 23 only during one rotation of the photoreceptor drum. After the photosensitive drum D completes the predetermined copying, it makes at least one more rotation and then stops. Further, the charging charger 18 is turned off after the completion of image formation for the final number of sheets, and a little later, the uniform exposure light source 19 is turned off. In the above apparatus, when heat fixing is employed as the semi-fixing means, oven fixing as described in the above-mentioned US Pat. No. 3,615,128 is easy, but a contact type using a heat roller may also be used. In the latter case, it is necessary to use a contact-separation type structure in which the heat roller is brought into contact with the surface of the photoreceptor drum only during semi-fixing, and is retracted at other times. In addition, in order to prevent toner from adhering to the heat roller surface, it is possible to apply an anti-offset liquid to the heat roller surface or place another heat roller inside the photoreceptor drum so that the toner adheres to the photoreceptor drum rather than the heat roller surface. It is desirable to make it easy to semi-fix on the surface. Furthermore, although a metal blade is used as a means for removing the original image from the surface of the photoreceptor, various materials such as stainless steel and aluminum alloy can be used for the blade. Note that the elastic blade used in conventional copying machines cannot completely remove toner semi-fixed on the surface of the photoreceptor. Next, examples of the present invention will be described. Example 1 Monosilane gas (10
%SiH ₄ ), diborane gas with hydrogen as a carrier gas, and oxygen gas as source gases, and the ratio of oxygen to monosilane (O ₂ /SiH ₄ ) and the ratio of diborane to monosilane (B ₂ H ₆ /SiH ₄ ). Each
10 ^-4 , 1×10 ^-4 is supplied to a known glow discharge decomposition device, the device internal pressure is 1.5 Torr, and the supplied power is 300 W/hr.
1,500 Å / 1,500 Å /
A-Si is produced at a rate of 1.5 min to produce an a-Si photoreceptor drum having a photoconductive layer with a thickness of 20 μm. The a-Si photoconductive layer of this a-Si photoreceptor drum contains 18 to 22 atomic percent hydrogen, 0.01 atomic percent oxygen, and 200 ppm boron, and its dark volume resistivity is 8×10 ¹³ Ω·cm. The Bitkers hardness ( _Hv50 ) was approximately 2250Kg/ ^mm2 . This a-Si photoreceptor was used as the photoreceptor of the copying machine shown in Fig. 2, and per one document under the following conditions.
When 100 sheets at a time were continuously copied up to 10,000 sheets, a good original image with high contrast was obtained. Further, no damage to the surface of the photoreceptor was observed. Photoreceptor rotation speed: 40 rpm Charger supply potential for charging: -5.6KV Image exposure amount: 3lux・sec Exposure amount by light source for uniform exposure: 5lux・sec Charger supply potential for transfer: 6KV Charger supply potential for separation: 6.5KV Metal blade : Stainless steel (SUS303) Eraser exposure amount: 200 lux·sec Example 2 An aqueous solution containing 308.5 g of cadmium nitrate and an aqueous ammonium carbonate solution were mixed to react, and cadmium carbonate was precipitated. 173 g of this cadmium carbonate was dispersed in water containing 0.68 g of cupric chloride, and hydrogen sulfide was blown into the water to form a precipitate of CdS·nCdCO ₃ to which Cu had been added. Subsequently, this precipitate was washed with water, dried and ground, and heated at 250℃ for 15 minutes.
A photoconductive powder of CdS·nCdCO ₃ (n=1.5) was obtained by firing for a period of time. 100 parts by weight of this photoconductive powder was kneaded with 60 parts by weight of thermosetting acrylic resin and 130 parts by weight of a mixed organic solvent containing toluene as the main ingredient, thoroughly dispersed, and then placed on an aluminum cylindrical substrate with a diameter of 80 mm. An intermediate layer having a thickness of 30 μm was formed by spray coating and heat curing. Furthermore, the specific resistance of this intermediate layer is 5×10 ¹³
It was Ω・cm. An interlayer comprising zinc selenide photoconductive material was then formed on another similar aluminum substrate. First, dissolve 300 g of zinc nitrate (Zn(NO ₃ ) ₂ 6H ₂ O) in distilled water, and dissolve 1% of copper chloride (CuCl ₂ 2H ₂ O).
Add 68ml of aqueous solution, drop 120g of ammonium selenide dissolved in distilled water to the solution,
A precipitate of zinc selenide with added Cu was obtained. After washing and drying this precipitate, it was calcined in an inert gas (Ar, N ₂ ) at a temperature of 600°C for 1 hour, and the ZnSe powder thus obtained was mixed and dispersed with a thermosetting acrylic resin and a toluene solvent. , spray coated onto an aluminum substrate. After drying, it was heated and cured to form a ZnSe binder intermediate layer with a thickness of 30 μm. When its specific resistance was measured, it was 6×10 ¹³ Ω·cm. Furthermore, separately from this, an As ₂ Se ₃ intermediate layer with a thickness of 30 μm was formed on the same aluminum substrate. Purity 99.999
Se and As pellets with a particle size of 1 mm or more and an atomic ratio of 40%:60% were mixed, and 120g of the mixture was placed in a quartz ampoule for 10 ^-5 ~
After drawing a high vacuum of 10 ^-6 Torr, seal it off. This ampoule was placed in an electric furnace and heated at about 800°C for 10 hours to melt As and Se. This was mixed sufficiently uniformly and then rapidly cooled to obtain an alloy lump of As ₂ Se _3. This lump was taken out and ground sufficiently finely in a mortar, and then set in the evaporation source of a vacuum evaporation apparatus. After setting the aluminum drum substrate as the evaporation substrate, the inside of the evaporation tank was evacuated to a vacuum level of approximately 5 × 10 ^-5 Torr, the substrate was heated to approximately 200°C, and then the evaporation source temperature was raised to 420 to 460°C. 1 second to start vapor deposition.
As ₂ Se ₃ with a thickness of 30 μ at a deposition rate of 100 Å to 200 Å
An intermediate layer was formed. Furthermore, the specific resistance of this intermediate layer is 4
×10 ¹³ Ω・cm. Next, each of these cylindrical substrates was installed in the glow discharge decomposition apparatus used in Example 1, and a 5μ thick a-Si photoconductive layer was laminated on the intermediate layer under the following conditions. A photoreceptor was obtained. [A-Si photoconductive layer formation conditions] Reaction tube internal pressure 1.5Torr Power supply 300w/hr (frequency 4MHz) Substrate temperature 200℃ Film formation rate 1500Å/min Raw material gas 10%SiH ₄ -90%H ₂ mixed gas O ₂ / SiH ₄ molar ratio 2.75×10 ^-4 B ₂ H ₆ /SiH ₄ molar ratio 10 ^-3 Each photoreceptor obtained contained 18 to 22 atomic percent hydrogen, 0.05 atomic percent oxygen, Contains 200ppm boron, dark volume resistance 4×10 ¹⁴
Ω・cm, Bitkers hardness (Hv ₅₀ ), approximately 2200
It was Kg/ ^mm2 . When copying was performed using this photosensitive drum under the same conditions as in Example 1, a good image with high contrast was obtained. Examples 3 to 6 An a-Si photoreceptor having a photoconductive layer having the composition shown in the table below was prepared in the same manner as in Example 1 or Example 2, and under the same conditions as in Example 1, 100
Continuous copying was performed up to 10,000 sheets at a time. The results are also shown in the table. 【table】

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the progress of each process in the method of the present invention, and FIG. 2 is a cross-sectional view of an electrophotographic copying machine used to carry out the method of the present invention. 1 - photoreceptor, 2 - charging means, 3 - Original, 4-powder image forming particles (toner), 5-unfixed toner, 6-
transfer charger, 7-transfer paper, 8-metal blade, 11-document stand, 13-exposure lamp, 14,
16-mirror, 15-projection lens, 17-exposure slit, 18-charging charger, 19-uniform exposure light source, 20-developing device, 21-transfer charger, 22-separation charger, 23-metal blade, 24 ~ Eraser lamp, H ~ Semi-fixing device.

Claims (1)

[Claims] 1a After forming an electrostatic latent image on the surface of an amorphous silicon photoreceptor and developing the diagnostic electrostatic latent image with a powder developer to form a powder image, the powder image is transferred to the photoreceptor. An original image creation process in which an original image is created by semi-fixing it on the surface, b. The surface of the photoreceptor on which the original image was created is charged, the surface of the photoreceptor is uniformly exposed to form an electrostatic latent image on the original image, and then a powder developer is applied. c. After repeating the copy creation step, the surface of the photoreceptor is An electrophotographic copying method comprising: a photoreceptor regeneration step in which the original image is removed using a metal blade.