DE2253899A1 - ELECTROPHOTOGRAPHY PROCEDURE - Google Patents

Description

The invention relates to an electrophotography process, in which a liquid developer is used. The method includes developing electrostatic latent images with a liquid developer, especially on a light-sensitive structure or body for electrophotography, transferring the developed images onto a transfer material and the Cleaning and repeated use of the light-sensitive body after use.

Various methods of electrophotography are already known, of which the following are commonly used:

In a first electrophotography method, a photoelectrically conductive layer, for example a layer of the ZnO resin binder system and of polyvinyl carbazole,

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which is formed on the surface of a support material, in general paper or a resin film which has been made electrically conductive and is electrostatically uniformly charged. Exposing the surface to the original images creates electrostatic latent images which are then developed with a developer in either a dry or wet process. This is followed by fixing the developed images on the photoelectrically conductive layer, for example by heating, so that a duplicate is obtained. This process is one of the non-transferring electrophotography processes.

In a second method, a photoelectrically conductive layer, for example made of amorphous selenium and the ZnO resin binder system, is applied to a carrier material, which is generally a metal plate. The whole surface is then charged uniformly. By exposing the Electrostatic latent images are created on the surface with the original images. The pictures are with developed in a dry developer. The images developed in this way are transferred to a material, for example on a sheet of paper followed by fixing by heating to obtain a duplicate or a print. After the photoelectrically conductive layer has been cleaned, it can be used again.

In a third method, a photosensitive plate which has a photoelectrically conductive layer, for example made of CdS, and on the immediate surface further having thereon an insulating layer; Corona charged evenly over the entire surface. This plate is exposed to the original images with simultaneous corona charging with the reverse phase or alternating current charging or charging with alternating current, which leads to the formation of the electrostatic latent

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Images are followed by an even exposure to light. The images are then developed with a dry developer, the developed images are transferred to a material, for example a sheet of paper, and then fixed by heating, to get a duplicate or an image. The photosensitive plate can be used repeatedly after cleaning will.

The second and third methods are among the methods of electrophotography using transfer.

Electrophotographic processes employing transfer using a liquid developer such as that in accordance with the present invention should be the case so far are for practical use due to various technical difficulties not yet developed.

According to the invention, these various technical difficulties are resulting from electrophotography with transfer and use of a liquid developer, been solved ,, whereby in particular the transfer procedure, the transfer material and the cleaning method have been improved.

According to the invention, a method is to be created at which electrostatic latent images formed on a photosensitive body for electrophotography have been developed with a liquid developer. Then the depth of the remaining developer liquid on the photosensitive body sufficiently regulated to the effectiveness of the transfer and of fixing as well as the resolving power of the transferred Improve pictures.

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A second object of the invention is to provide a transmission «- to create material on which the images are of good quality can be transferred. Furthermore, a technique is to be used of the photosensitive body can be found, whereby the body can be used repeatedly.

According to the invention, the electrophotography process should that works with transfer and uses a liquid developer can be improved, with electrostatic latent Images on a photosensitive body for electrophotography be formed. These latent images are developed with a liquid developer, which the Transfer of the developed images to a transfer material and the light-sensitive body is cleaned so that it can be used repeatedly.

In order to transfer these images made up of electrostatic latent images onto a photosensitive body for the Electrophotography can be produced by developing with a liquid developer onto a transfer material To achieve high efficiency, a suitable amount of the developer must be used at the time of transfer between the photosensitive Body and transfer material (usually a sheet of paper). If there is between the photosensitive Body and the sheet of paper forming an empty space in which there is no developer is done on this part no transfer. This is because the transfer of visible images is in the wet development process mainly depends on the electromigration or the electron transfer. On the other hand, if the developer is on the light-sensitive body is present in large quantities, the developed images are transferred to the transmission medium transferred, but at the same time there can be a flow or Moving the pictures · adjust, increasing the resolution which adversely affects the images. Also makes

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the developer adhering to the transfer material and sucked into this material, either long-term heating or a high-capacity heat source required, to dry the transfer material and fix the visible images. Additionally occurs from the liquid Developer steam out and adversely affects the hygienic condition of the environment.

In order to improve the quality level or the efficiency when transmitting, the above difficulties must be eliminated. You can see visible images on the photosensitive body however, cannot be completely transferred to a transfer material. Therefore the body must be purified so that it can be used repeatedly.

For repeated use, the light-sensitive The body should be as completely free of developer solution as possible. However, complete removal requires that the Surface of the photosensitive body is processed very intensively with a pressed blade, whereby its Surface may be damaged or its durability may be reduced.

On the other hand, if the pressure is insufficient, the developing solution can cannot be completely removed and therefore forms a thin layer on the surface. This is an undesirable one Effect of the process known as "fogging on the entire substrate or on the entire base "is designated.

According to the invention, a method for cleaning has now been found in which neither damage to the photosensitive Body, still a haze occurs on the whole surface. By using this process step as well as the improved process step when transferring,

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as mentioned above, the whole electrophotography process markedly improved using the transfer and use of a liquid developer.

The present invention thus provides a method of electrophotography in which the following steps can be continuously carried out, namely, developing with a liquid developer, whereby electrostatic latent images formed on a photosensitive body for electrophotography are visualized. The photosensitive body is composed of a substrate and a photoelectrically conductive layer as basic components. Furthermore, the liquid depth of the remaining developer solution on the photosensitive body is regulated to 5 to 30 μ by squeezing it flat with a corona discharge. Finally, the images developed on the photosensitive body are electrostatically transferred to a transfer material and fixed on it. Subsequent to the transfer treatment, the photosensitive body is cleaned so that a layer of the liquid developer more than 1μ thick does not remain.

A preferred embodiment of the invention is explained below.

The photosensitive body used in the present invention to form the electrostatic latent images thereon Surface must have at least the following properties for the invention to be effectively carried out and to be effective receives satisfactory results. The photosensitive body should therefore

1. Be impermeable and must not dissolve in the developer (mainly in the carrier liquid)

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2. Sufficient resistance to electrical Have voltage to hold the electrical charge, and

3 · have high mechanical resistance that allows repeated usability «

As in the known electrophotographic processes, the photosensitive body can be produced by an inorganic photoelectrically conductive material, for example ZnO, Se and CdS, organic photoelectrically conductive material such as N-vinylcarbazole and oxyadiazole, and a photoelectrically conductive layer composed of a dispersoid system of a photoelectrically conductive material and a binder is applied or vacuum deposited, or that a top layer on a photoelectrically conductive layer is provided or that on a photoelectrically conductive material and / or a Binder a selected material is applied that meets the above requirements under 1 to 3.

A photosensitive one most suitable for the present invention Body, for example, is focused on electrophotography referring Japanese patent application Sho 42-2391 ° «This body is at least made of one electrically conductive carrier material, one photoelectrically composed of a conductive layer and an insulating layer.

Such a photosensitive body is, for example drum-shaped and either by vacuum evaporation one photosensitive material on the drum-shaped support or by applying a flexible plate of photosensitive em material around a drum-shaped carrier manufactured. Further devices for treatments belonging to the usual electrophotography are corresponding

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placed close to the photosensitive body lengthways treat this work road. For example, a corona discharge device is placed around the light-sensitive body, an exposure device and a device for liquid development arranged to to form visible images on the photosensitive body. Furthermore, a corona charge squeezer for controlling the liquid depth on the developer, a discharge device for transferring and a cleaning device for cleaning the photosensitive Body provided.

Latent images can be made from the original images as described in the Japanese patent applications Sho 42-239I0 and 4Ί-256ο can be found.

In particular, electrostatic latent images are formed on the photosensitive body by means of a peripheral device formed and developed with a liquid developer.

The liquid developers are made of an insulating liquid with an insulation effect greater than Io / 2. cm is off Composed of toner particles and a charge control agent. Such liquid developers are, for example, in the Japanese Patent applications Sho 35-5511, 35-13424 and 36-14872 described. The mean diameter of the toner particles is between 0.5 and 10, preferably between 1.0 and 5.0 μ, since smaller particles improve the quality of the transmission and with larger particles the fine structure of the images is lost.

The contact of these liquid developers with the photosensitive surface reveals the electrostatic latent images formed on the photosensitive body .

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The photosensitive body then goes to the next stage of treatment brought, with he on the surface a carries large amounts of insulating liquid and toner particles, which form the visible images.,

Since the insulating liquid is necessary when transferring, should a certain amount of liquid should be present on the surface. However, this should be avoided Amount is large, as explained earlier. The photosensitive body is then placed in a device for the Corona discharge flat squeezing or pressing brought to the Adjust the liquid depth of the developer solution to the the surface of the photosensitive body remains.

When transferring or transferring the images, the suitable depth of the developer solution that remains on the surface of the photosensitive body is about 5 to 3 °, in particular 10 to 20 and tests have shown that a depth of less than 5 of residual developer on the surface creates a space between the photosensitive body and a transfer material * This results in unevenly transferred images, so that good quality images can hardly be obtained. On the other hand, if the depth of the liquid is greater than Jo u, the transfer material becomes so saturated with the developer that fixing and drying become very difficult and the resolving power of the transferred images is lowered.

The method and its results are described below.

A mixed dispersoid, which consists of 100 g of microcrystalline cadmium sulfide, 10 g of a 50% solution of vinyl chloride-vinyl acetate mixed polymer in toluene and 80 g of toluene, is applied to a 0.05 "*" thick aluminum foil,

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that you get a ko μ thick dried layer. A 38 µm thick polyethylene terephthalate film is attached thereon with an epoxy resin adhesive having a low curing temperature, so that a three-layer photosensitive body is obtained. The surface of the insulating layer of the above photosensitive body is uniformly charged by the corona discharge at + 7kV. Then the surface with the original images is exposed with simultaneous AC corona discharge at 7 kV, whereupon the entire surface is exposed to light to obtain electrostatic latent images. On the other hand, a mixture of 3ä ring-shaped rubber, 2 g of polyethylene of dispersed low molecular weight, 2 g of carbon black and 3 ° S xylene and kneaded for twelve hours in a ball mill and then dispersed with a homogenizer in 1 1 of an electrically insulating liquid (Isopar G) containing ko mg of lecithin, whereby the liquid developer is obtained. The mean diameter of the particles in this developer is 2 to 3 µ · Using this developer, the above electrostatic latent images are developed. Clear images (density or blackness 1.7) are obtained on the surface of the photosensitive body. The developing solution remaining on the photosensitive body is about 60 µl.

Then, the corona discharge flattening is performed at the discharge voltage as shown in FIG The table below shows the depth of liquid on the surface of the photosensitive body to regulate remaining developer. The images are transferred by the corona transfer in about 0.25 α on a transfer paper which has an oil absorption coefficient of 135 * and a surface smoothness of loo s. The scored Images are fixed by drying with warm air. The. Blackening, the resolving power and the degree of dryness

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be determined. The density of the images is measured with a reflection density meter. The degree of dryness is determined from the ratio, multiplied by 100%, of the amount of liquid contained in the paper after drying to the amount of liquid contained in the paper immediately after transfer. The dryer used here works with it direct heating by means of infrared light (800 W), the distance between the heating wall and the transfer paper being 10 mm and the feed speed of the transfer paper being 10 mm / s.

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Tension for
the corona
Discharge
Smooth
kV Liquid
deep before the
transmission
in μ Blackening
of the transferred
like picture Drying
Degree
in % Dissolution
capital
(Lines)
in mm Uniform
ability of the about
carried image 7.2 2 to 3 1.25 98 8th available 309 7, o
6.5 5 to 6
Io to 12 1.47 95
91 6.3
6.3 almost no
no α> 6.2 18 to 20 1.55 85 6.3 no ο 6.0 28 to 30 1.65 80 5.6 no φ
04 5.5 38 to 4o 1.68 7o 4.5 no

The smoothing or flattening by the corona discharge is done with a
gold-plated tungsten wire 0.06 mm in diameter, the
Distance between the photosensitive body and the wire is about Io mm.

The optimal time for the transfer according to the invention is about 0.2 to 1.0 s, depending on the developers and the transfer condition depends. The transfer materials should be sufficiently resistant to loosening or have the properties of anti-oil absorption, as a Absorption of the developer during the transfer is undesirable. Furthermore, the transfer materials should also have a smooth surface so that better contact with the photosensitive body is obtained.

Accordingly, the transfer materials used in the present invention should have an oil absorption coefficient of over 50 s or an anti-oil absorption property of over 0.5 s. The surface roughness (or the surface smoothness) should be above 3o ^s t, preferably between 5 <> to 150 s. which are reflected on the surface of a drop of 0.04 cm Isopar G, which is placed on a horizontally held piece of paper to be examined with an injector with a subcutaneous injection needle I / 3 (HS 0.5 + 0.02 to 0.5 - o, oil mm outside diameter, 23 + 1 mm length and 12 ° point angle). In other words, this means that the period of time is to be understood in which a drop of liquid is completely absorbed into the paper to be examined. The anti-oil absorption property is expressed as the time in seconds in which a drop of Isopar 6, applied in the same way as in the case of the determination of the oil absorption coefficient, covers the entire area (with a diameter of approximately Io mm) of the paper under the drop makes transparent, whereby for. Measuring a stopwatch is used. The surface roughness is determined by the Beck ¹ see method (according to the Japanese industrial standard JIS-P8II9)

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-Ik-

When transferring, about 2o to 5o %, preferably about 3o %, of the liquid depth of 5 to 3o u of the developer on the surface of the photosensitive body before transfer should remain on the surface after transfer, ie about 2 to 15 u depth or Strength of developer solution. This is necessary in order to avoid blurring of the transferred characters and to regulate developer stains on the transfer material, taking into account the surface roughness and the anti-oil absorbency of the transfer materials.

After transferring, the photosensitive body becomes one Cleaning device where the 2 to 15 P-deep liquid, remaining on the surface of the photosensitive body is removed.

The cleaning can be done by pressing a blade or a roller or a brush against the photosensitive body to remove the remaining solution. That Cleaning should be done so that the depth of the developer solution on the surface of the photosensitive body is less than 1 µ. For this purpose is expedient the blade material made of polyurethane resin

2 with a pressure of more than 5 kp / cm.

The invention is explained in more detail on the basis of the examples below.

example 1

It is produced a photosensitive body by a 60 ρ thick aluminum foil was a solution in toluene and chlorobenzene 2,5-öis- (p-Diüthylaminophenyl) -1.31 k- oxadiazole as a photo-electrically conductive material, polycarbonate

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(Yubin E 2ooo, Mitsubishi Resin Co.) as a binder resin and Rhodamine B as a sensitizer in weight ratio of 1: 1: o, ol5 is applied, so that a film layer with a thickness in the dried state of Io η is obtained.

The surface of this photosensitive body is uniformly charged with the corona discharge at -5.5 kV and exposed to the original images, so that electrostatic latent images are formed. The images are developed with a commercially available liquid developer, whereby clear images are formed on the surface of the photosensitive body. The developing solution remaining on the surface of the photosensitive body is about 60 ρ deep. The depth of the liquid is set to about 15 M. by means of the corona discharge at 6.5 ^ V. Then, it is transferred in about 0.2 seconds by corona transfer to a transfer paper which has an oil absorption coefficient of 135 seconds and a smoothness of 10 to 12 seconds. This is followed by cleaning with a polyurethane blade so that the liquid depth is reduced to less than 1 μ.

The above process is carried out repeatedly. The results are satisfactory on each attempt and a clear and distinct duplicate is obtained.

Example 2

A photosensitive body is produced as in Example 1, in which a toluene and chlorobenzene solution of 2,5-bis (p-dimethylaminophenyl) - !, 3,4-oxadiazole on a 60 u thick aluminum foil as photoelectrically conductive material, an acrylonitrile-styrene mixed polymer resin (Estyrene A-2o, Union Carbide Co.) as a binder resin and a colorant having the following structural formula as a sensitizer is applied in a weight ratio of 1: 1: o, ol5, so that you get an Io μ thick dried film

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^16-2283899

receive. The subsequent treatment speaks of the von Bei, ^c »piel 1 and mau receives a clear and unambiguous feeling

_Y CH = (H - CII -----

^ C

N '

Example β

A mixture of l'jo ml of acetonitrile containing 4 g of copper (l) - iodide and 3 ° ml of a 5% solution of polyvinyl formaldehyde is applied to a 9o μ thick polyethylene terephthalate plate and dried so that the surface of the plate is electrically is conductive. Then a solution with 3 g of vinyl acetate resin per 5 oo oil is applied to the surface of the plate, so that a 6 μ thick dried film is obtained. The solution of the following composition is applied to this product, so that a 7 μ thick dried film is obtained and a double-layer photosensitive body is created. The composition consists of Si g poly-N-vinylcarbazole, 2 mg 2,4,7-trinitrofluorenone, 5 mg 3,3 ', 3 "-TricarbasSolylmethylchiorid and 50 mg monochlorobenzene.

The surface of this photosensitive body becomes uniform charged by corona discharge at + 7, ο kV and with the Original images are exposed, thereby forming electrostatic latent images. The electrostatic latent images are developed with a known liquid developer so that clear images can be obtained on the surface of a photosensitive body. Then the liquid depth on the

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BATH ORIGINAL

lichtriiipfiml L fief body aiii "about LfJ π by 'the corona-Ent charge at ~ (> ,. ^r > kV e üiejos t el 11 and the images are transferred to ta Ln paper sheet, cm, whose 0 absorption coefficient 1} [> - s and dijiiistin GLa "t te. Loo α . This is followed by cleaning with a KlIngo. The above procedure is repeated. The results obtained are as good as those of Example i.

Example (t

The surface of a well- polished aluminum drum is plated by vacuum evaporation TiL 99 »999% pure selenium to a strength of 5 ° to 6o u under a vacuum of 2 to 5 x Io mmHg and at a base temperature of 65 ° C, so that one double-layer photosensitive body. The surface of the photoelectrically conductive layer is then uniformly charged by the corona discharge at +7 kV and exposed to the original images, so that electrostatic latent images are formed. The images are developed with a liquid developer in the same manner as in Example 1 so that clear images are obtained on the surface of the photosensitive body. As shown in Example 1, the depth of the liquid on the photosensitive body is adjusted to about 20 µ by using the corona discharge at -6.2 kV. The images are then transferred to a sheet of paper which has an oil absorption coefficient of 135 s and a smoothness of llo s . This is followed by cleaning by means of a rotating brush, so that the depth of remaining developer solution is reduced to less than 1 µ. The above procedure is repeated and, as in Example 1, good results are obtained.

When the drum, its surface by vacuum evaporation with. Selenium is plated, used as a photosensitive body and developed with a liquid developer,

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BAD ORIGINAt

ULi (I da "OhorfLnchenmater La 1 iliis L ichtense I Lehen body. ¹ ! Be.'ich LeuuLgt Ln t! Ine kt converted into tai Lino form, the dlci IJL Idf όχι" Lei unfavorably influences *

When cleaning, at weLcheui the depth of the liquid on the photosensitive body on under I ti by treatment with a blade, a roller or a brush is reduced, however, the crystallized layer is likely to be on the surface of the photosensitive together with the liquid developer Body removed. This will deactivate the photosensitive body as a result of the crystallization of the Surface layer prevents and you get good pictures Quality.

Example 5

A mixture consisting of 100 g of microcrystalline cadmium sulfide, 10 g of a 5% solution in toluene of vinyl chloride-vinyl acetate copolymer and 80 g of toluene is applied to a 0.05 mm thick aluminum foil, so that a ko μ strong dried film. A 38 U thick polyethylene terephthalate film is further applied with an epoxy resin adhesive which cures at a low temperature, so that a three-layer photosensitive body is obtained. The surface of the insulating layer of the photosensitive body is uniformly charged by corona discharge at +7 kV and exposed to the original images, at the same time as the alternating current corona discharge at 7 kV. Then the surface is exposed to light uniformly so that electrostatic latent images are obtained. A mixture consisting of 3 g of ring rubber (cyclic rubber), 2 g of low molecular weight polyethylene, 2 g of carbon black and 30 g of xylene is then dispersed and kneaded for twelve hours with a ball mill and then poured into 1 liter of an electrically insulating liquid (Isopar G. ) dispersed,

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BATH ORIGINAL

ko / ng Lecithin contains a Hoinogenisiernngsmittel is produced whereby a liquid developer * Using this developer, the representational elöktrostatischen latent images are developed, so that clear images obtained on the surface of the photosensitive body. The depth of the desiccator solution on the surface is about 60 μ.

Then the corona discharge is carried out at 6.4 kV in order to reduce the depth of the developer solution on the surface of the light * sensitive body to 15 μ »Then the images are transferred to a transfer paper in 0.25 s using the corona transfer process , which has an oil absorption coefficient of 15o s and a smoothness of loo s, whereby the images are dried with warm air * This gives extremely clear and well-fixed images.

The depth of the on the photosensitive body according to the Transfer remaining developer solution is about 5 J ^ * This thickness is reduced to less than 1μ by cleaning with a polyurethane blade. The process is repeated carried out. The results obtained are always good «

Example 6

A zinc oxide resin paste made up of the following components is composed of * is on a ο »ο *> mm thick aluminum * foil applied with a piece of wire so that an 18 to 22 μ strong dried visual film is formed. Through this you get a two-layer light-sensitive body *

The zinc oxide resin paste contains 100 parts by weight of photoelectrically conductive zinc oxide, 375 parts of poly

vinyl butylal (BM * 2, Sekisui Chemicals Co.), IS5 parts

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ORIGINAL BATHROOM

- 2ο -

Acrylic resin (LR-472, Nippon Reichhold Co.), 700 parts isopropyl alcohol, 800 parts xylene and 3 parts Dengal red (Rose Bengale) in methanolic solution.

These components are mixed in a ball mill and then mixed with a mixed solvent of isopropyl alcohol and xylene diluted until the particle size is reduced to about 600 cp. The mixture thus obtained is applied to the aluminum foil.

The surface of this photosensitive body is uniformly charged by the corona discharge at -7 kV and exposed to the original images, so that electrostatic latent images are obtained. On the other hand, the carbon black-resin mixture according to Example 5 is dispersed with a homogenizing agent in 1 liter of an electrically insulating liquid (Isopar G, Esso Co.) which contains 100 mg of cobalt naphthenate. The liquid developer thus prepared is used to develop the electrostatic latent images. Clear images can be formed on the surface of the photosensitive body by using the developer thus prepared. The depth of the developer solution on the surface is adjusted to about 15 U by applying the corona discharge at +7 kV. Then, the images are corona transferred onto a sheet of paper that has an ^{O1 absorption coefficient of 135 s} and a smoothness of I2o s. This is followed by cleaning with a rotating brush. The procedure is repeated. The results are as good as those of Example 1.

Example 7

In the same way as in Example 1, on a photosensitive Body produced visible images, the depth of the liquid developer being about 60 microns.

Then the smoothing is done by the corona discharge at 7 | O kV performed so that the liquid depth on the surface

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of the photosensitive body is set to 5 to 6 ti. Using corona transfer, the images are then transferred to transfer paper in about 0.25 seconds an oil absorption coefficient of 600 s and a smoothness of 3oo s has. The transferred images are made with warm air dried. Extremely clear and well fixed images are obtained.

After the transfer treatment, the depth is that on the Surface of the photosensitive body remaining liquid about 3 p · This liquid is through-cleaning with a polyurethane blade completely removed without any a noticeable amount of liquid remains on the photosensitive body.

Example 8

As with Example 5, visible images are made on a photosensitive Body formed, the depth of the liquid Developer is about 6o yes.

Then, the smoothing is carried out by the corona discharge at 6.0 kV to adjust the liquid depth on the surface of the photosensitive body to 28 to 3o / *. Then, by using corona transfer, the images are transferred in about 0.25 seconds to a transfer paper whose oil absorption coefficient is $ os and smoothness is 50s. The transferred images are dried with warm air. In this way, extremely clear and well-fixed images are obtained.

After the transfer treatment, the depth is that remaining on the surface of the photosensitive body Liquid about 7 p · This liquid is used when cleaning completely removed with a polyurethane blade without leaving any noticeable amounts of liquid on the photosensitive Bodies remain.

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Example 9

As in Example 5, visible images are generated on a photosensitive body, the depth of the liquid developer being approximately 60 μ .

Then, the smoothing is carried out by the corona discharge at 6.5 kV to adjust the liquid depth on the surface of the photosensitive body to Io to 12 μ . The images are then transferred to a transfer paper with an oil absorption coefficient of 3 ° os and a smoothness of 2oo s in about 0.25 seconds using corona transfer. The transferred images are dried with warm air. Extremely clear and well fixed images are obtained.

After the transfer treatment, the depth of the liquid remaining on the surface of the photosensitive body is about 4 µ , which is almost completely removed by cleaning with a polyurethane blade, and the depth of the liquid on the photosensitive body is then less than 1 µ.

Example Io

As in Example 5, on the surface of the photosensitive Body visible images created, the depth of the developer solution is about 6o u.

Then smoothing is done by the corona discharge at 6.4 kV performed to the liquid depth on the surface of the photosensitive body to be set to 15 μ. Afterward the images are transferred to a polyethylene terephthalate film in about 0.25 seconds using corona transfer (Mylar), their ola absorption coefficient

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oo s is. The transferred images are made with warm air dried. Extremely clear and well fixed images are obtained. After the transfer treatment, the depth is that on the Surface of the photosensitive body remaining liquid about 7 μ · This liquid is cleaned by cleaning With a polyurethane blade almost completely removed, the depth of the liquid on the photosensitive body then is less than 1 u.

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Claims (3)

PATENT CLAIMS 1. electrophotography method, characterized in that ^ - that electrostatic latent images formed on a photosensitive body for electrophotography, which is composed of a substrate and a photoelectrically conductive layer as basic components, are developed with a liquid developer that the Liquid depth of the developing solution remaining on the photosensitive body is adjusted to 5 to 3 ° P , that the developed images on the photosensitive body are transferred to a transfer material whose oil absorption coefficient is greater than 5 ° s, and are fixed on the material and that the photosensitive body Body is cleaned after the transfer treatment so that a more than 1 μ thick layer of the liquid developer does not remain. 2. The method according to claim 1, characterized in that the liquid depth of the developer solution remaining on the photosensitive body is adjusted to 5 to 3 ° μ by smoothing or flattening by the corona discharge and that the developed images on the photosensitive body on the transfer material are transmitted electrostatically. 3. The method according to claim 1 or 2, characterized in that the photosensitive body for electrophotography from a photoelectrically conductive layer on an electrically conductive carrier body and further composed of an electrical insulating layer which is optically transparent. 309820/0939 k * Method according to one of the preceding claims, characterized in that the depth of the developer remaining on the photosensitive body is adjusted to Io to 2o u by smoothing by the corona discharge. 5. Method according to one of the preceding claims, characterized in that the method steps can be repeated continuously. 309820/0939