FI57493C - ELECTRONIC PHOTOGRAPHY - Google Patents

Description

γβΙ ™ advertisement.su C74Q7 J§3Ta IBJ (11) UTLÄGCNINGSSKRIFT 0 '** 7 0 c (45):; .ί ... i 11' - :: 3 ^ (51) Kv.ik.3 / Int. a.3 G 03 G 13/14, 13/22 ENGLISH — FI N LAN D (21) Piwnttm ^ wmii · —p * t »« w »ekiiii» * 3oUi * / 72 (22) Hiktmlipttvi - An * 6knlnpd «G 01.11.72 (23) AlkupUvt — GiWglwttdif 01.11.72 (41) Tullut | ulklMlui - Bltvit offmtllg 05.05.73

Patent and Registration Office Nihttvltoip-κ * j. Monthly date—

Patent · och registerstyrelsen 'Ameksn utlagd och utijkmew pubiksmi 30. Ok. 80 (32) (33) (31) Requested prefix * —B «jtrd prlorltet 0U.ll.7i

Japan-Japan (JP) Sho 1 + 6-87762 (71) Canon Kabushiki Kaisha, No. 30-2, 3-chome, Shimomaruko, 0hta-ku,

Tokyo, Japan-Japan (JP) (72) Hiroshi Tsuchiya, Urawa-shi, Saitama-ken, Japan-Japan (JP) (7U) Oy Kolster Ab (5U) Electronic Photography - Elektronisk fotografering tsite The present invention relates to electronic photography using liquid developer. , which comprises generating electrostatic latent images specially formed on a photosensitive body by means of electronic photography with a liquid developer, transferring the generated images to a copying substrate, affixing therein and cleaning and reusing said photosensitive body.

Several electronic photographic methods have been proposed. The following are commonly used.

First, there is an electronic photographic method in which a photoelectrically conductive layer, such as a ZnO resin system and polyvinylcarbazole, is usually formed on a support material in paper or plastic film which is made electrically conductive, electrostatically uniformly charged, and electrostatic latent images are generated by radiation. then developing the developer by either a dry or wet method, followed by photovoltaic application of the developed images to a conductive layer 2 57493, for example by heating to obtain a copy. This method is part of non-portable electronic photography.

Secondly, there is a method in which a photoelectrically conductive layer, e.g., amorphous selenium and a ZnO resin binder combination, is applied to a support material, usually a metal plate, the entire surface is uniformly charged, electrostatic latent images are formed by irradiating the surface with the original images, and developed with a dry developer. , such as by heating on a paper sheet, to obtain a copy. The photoelectric conductive layer can be reused after cleaning.

Third is a method in which a photosensitive plate having an immediately photoconductive layer on its surface, e.g. CdS and also an insulating layer thereon, is uniformly charged by a corona over its entire surface, irradiated through the original images by simultaneously charging with an opposite phase corona or alternating current and exposed to light to form electrostatic images, which are then generated by a dry developer, and the generated images are transferred to another material, such as a sheet of paper, and attached by heating to obtain a copy. The photosensitive plate can be reused after cleaning.

Methods according to the second and third methods belong to transmission-type electronic photography.

Thus, transmission-type electronic photography using a liquid developer, as in the present invention, has not been developed in practice due to various technical difficulties.

The present invention solves a number of difficulties associated with liquid-type transfer-type electronic photography, and in particular improves transfer, transfer material and cleaning methods.

In other words, the present invention seeks to provide a copying method in which electrostatic latent images generated on a photosensitive body by electronic photography are generated by a liquid developer and then the depth of the developing fluid remaining on the photosensitive body is suitably adjusted to improve transfer image transfer, attachment and resolution.

Another object of the present invention is to provide a transfer material to which good quality images can be transferred. Another object of the present invention is to provide a method for cleaning a photosensitive body so that it can be used over and over again.

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As mentioned above, the present invention improves transmission-type electronic photography using a liquid developer, in which electrostatic latent images formed on a photosensitive body by electronic photography are generated by a liquid generator, after which the generated images are transferred to a transfer material and the photosensitive body is cleaned for reuse.

To achieve high efficiency in transferring to the transfer material these images made on a photosensitive body by electrotreatment of electrostatic latent images obtained by electron photography, a sufficient amount of developer must be present during transfer from the photosensitive body to the transfer material (usually a sheet of paper). If a blank space is formed between a photosensitive piece and a piece of paper that does not have a developer, the transfer will not occur at that point. This is because when transferring visible images in the wet development method, the transfer depends mainly on electromigration. On the other hand, if there is too much development in the photosensitive body, the developed images will be transferred to the transfer material, but at the same time the images will tend to shift and flow, which will impair the resolution of the images. Furthermore, a developer that adheres to and is absorbed by the transfer material either needs a long time or a large amount of heat to dry the transfer material and fix the visible image. In addition, the developing liquid forms gases that pollute the hygienic state of the environment.

The aforementioned difficulties must be eliminated in order to improve the efficiency of the transmission. But visible images on a photosensitive body cannot be completely transferred to the transfer material and the body must therefore be cleaned for reuse.

When a photosensitive body is reused, it should be completely free of developer solution. However, for complete removal, it is necessary to press the surface of the photosensitive body relatively hard with a blade that can damage the surface or reduce its durability.

If the pressure on the other side is insufficient, the solvent front is not removed completely and forms a thin layer on the surface. This causes an undesirable operation of the method and is called "complete fogging of the bottom".

In this context, the inventors have found, as a result of thorough research, an excellent cleaning method which does not damage the photosensitive body and does not cause the entire surface to be hazy. By using this method as well as the above-mentioned improved transfer method, the transfer-type electronic photography using the previous liquid generator has been considerably improved.

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In summary, the present invention is a continuous photocopying method for electronic photography, characterized in that the layer thickness of the developer remaining on the light-conducting layer is adjusted from 5 to 30 and the surface roughness is 30 to 150 seconds as measured by the Beck method according to JIS-p 8119.

The photosensitive body used in the present invention on the surface of which the electrostatic latent images are formed must have at least the following characteristics in order to perform the present invention effectively and to obtain satisfactory results; the photosensitive body must 1. be impermeable and insoluble in relation to the developer (mainly a support in a liquid), 2. have sufficient electrical voltage resistance to maintain electrical charges, 3. have sufficient mechanical strength for repeated use.

As in previous electron photography, a photosensitive body can be prepared by brushing or vacuum vaporizing an inorganic photoelectric material such as ZnO, Se and CdS, an organic photoelectric material such as N-vinylcarbazole and oxiadiazole and a photoelectrically conductive layer, a photoelectrically conductive layer, of a binder or by forming a coating layer on the photoelectric conductive layer or further applying a photoelectrically conductive material and / or a binder to a selected material having the above-mentioned three properties 1-3.

For the purposes of the present invention, the most suitable photosensitive bodies may be those used in the electronic photography disclosed in Japanese Patent Specification Sho 42-23910, which consist of at least a photoelectric conductive support material, a photoelectrically conductive layer and an insulating layer.

For example, the aforementioned photosensitive body is made into a drum either by vacuum vaporizing the photosensitive material on a drum-shaped support or by attaching a flexible sheet of photosensitive material to the drum-shaped support and other devices for processing required by conventional electronic photography are conveniently placed in the vicinity. For example, a corona discharge device, a radiator and devices for liquid development are placed around the photosensitive body to form visible images on the photosensitive body. Further, a Korona emergency sweep device for adjusting the depth of the developing fluid, a discharge device for transfer, and cleaning devices for cleaning the photosensitive body are placed in its vicinity.

Latent images of the original images can be prepared according to the methods disclosed in Japanese Patent Publication Sho 1 + 2-23910 and UI + -2560.

More specifically, electrostatic latent images are formed on a photosensitive body by environmental devices and images are developed by a liquid generator.

Fluid generators consist of an insulating fluid with a resistivity of. 9.

greater than 10 ohm-cm, from the smoking parts and the charge regulator, such as those known liquid developers disclosed in Japanese Patent Publication Nos. Sho 35-5511, 35-13l + 2U, and 36-IU872, wherein the average diameter of the tinting particles is mostly 0.5-10, 0 ^ u, preferably 1.0-5.0 ^ u, because the smaller particles reduce the transmission efficiency and the larger particles destroy the fine structure of the images.

By contacting these fluid generators with a photosensitive surface, the electrostatic latent images formed on the photosensitive body are displayed.

The photosensitive body is then transferred to the next processing step, where a large amount of insulating liquid is placed on the surface, as well as the tinting particles forming the visible images.

Since the insulating liquid is necessary for the transfer, it is desirable to have some liquid on the surface. However, the presence of large amounts should be avoided, as mentioned above, and the photosensitive body is then transferred to a Corona discharge wiper to adjust the depth of the developing fluid on the surface of the photosensitive body.

When transferring images, a suitable depth of developing solution remaining on the surface of the photosensitive body is about 5 ~ 30, preferably 10-20. Based on the test result, if less than 5 yU of developer is left on the surface, a blank space is formed between the photosensitive body and the transfer material, resulting in unevenly shifted images and unsatisfactory image quality. On the other hand, if the liquid layer is thicker than 30, the developer is absorbed so much in the transfer material that attachment and drying become considerably more difficult and, in addition, the resolution of the transferred images is reduced.

The procedure and the results obtained are shown below.

A mixed dispersion containing 100 g of microcrystalline cadmium sulfide, 10 g of a solution of 6 57493 50 # of vinyl chloride-vinyl acetate copolymer in toluene and 6 θ g of toluene was applied to a 0.5 nm thick aluminum film to obtain a dried layer of U0 μ u. On top of this, a 38 μm thick polyethylene terephthalate film was attached with a low-temperature curable epoxy adhesive to obtain a three-layer photosensitive body. The surface of the insulating layer of the above-mentioned photosensitive body was evenly charged by Korona discharge at a voltage of 7 kV. The surface was then irradiated via the original images using a simultaneous 7 KV AC corona discharge, after which the entire surface was charged to obtain electrostatic latent images. In addition, a mixture of cyclic rubber 3 g of low molecular weight polyethylene 2 g of carbon black 2 g of xylene 30 g was dispersed and triturated for 12 hours in a ball mill and then dispersed in a homogenizer in 1 liter of electrically insulating liquid (trade name Isopar G) containing UO mg lecithin, for the preparation of a liquid developer. The average diameter of the particles in this development was 2-3 μ. Using this development, the above-mentioned electrostatic latent images were developed, resulting in bright images (density 1.7) on the surface of the photosensitive body. The thickness of the developing solution remaining on the surface of the photosensitive body was about 60.

Thereafter, a corona discharge scan was performed with the voltage shown in the following table to adjust the thickness of the developing solution remaining on the surface of the photosensitive body, and the images were transferred by corona transfer in about 0.25 seconds to a transfer paper having an oil absorption coefficient of 135 sec. and surface smoothness 100 sec. and the obtained images were fixed by drying with hot air. Density, resolution and drying index were measured. The density in the images was measured using a reflection densitometer. The dryness index was determined according to the formula (amount of liquid in the paper after drying) χ ^ 00 (amount of liquid in the paper immediately after transfer) and the dryer used was a direct heating type infrared lamp (600 watts power) with a heater wall distance of 10 mm and a transfer paper speed of 100 mm / sec.

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Corona Bore- Depth of Liquid Transferred Dryness- Resolution Seasonal Wiping of Transferred Image Before Transfer Image Index (Lines / mm) Unevenness Fermentation (, u) Heys (%) Volume '_ 7.2 2-3 1.25 98 8 Yes 7.0 5 -6 1.1 * 0 95 6.3 almost no 6.5 10-12 1.1 * 7 91 6.3 no 6.2 18-20 1.55 85 6.3 no 6.0 28-30 1.65 80 5.6 no 5.5 38-1 * 0 1.68 70 U, 5 no

Note: The Koran discharge scan was performed with 0.06 mm diameter gold plated tungsten wire with a distance of about 10 mm between the wire and the photosensitive body.

The optimum time for the transfer according to the present invention is about 0.2-1.0 sec. depending on the development and transfer conditions. Adequate solvent resistance (or resistance to oil absorption) is required of the transfer material because absorption of the developer during transfer is not desirable. Furthermore, the surfaces of the transfer materials must be smooth to make better contact with the photosensitive body.

Accordingly, the transfer materials used in the present invention are required to have an oil absorption coefficient in excess of 50 sec. or the anti-oil absorption property exceeds 0.5 sec. and the surface roughness (or surface smoothness) exceeds 30 sec, preferably 50-150 sec. The above oil absorption coefficient means the time in seconds, measured on a stopwatch, during which the test piece is placed on a horizontal piece of paper with a hypodermic injection needle 1/3 (HS, 0,5 + 0,02 -0,5 to 0,01 mm outside diameter, 23 ± 'mm in length). and 12 ° acute angle)

O

the reflection image of a point light source reflected from the surface of an Isopar G droplet (0.001 * cnr) placed with a syringe disappears (i.e., the time interval at which the liquid droplet is completely absorbed into the paper to be tested). The anti-oil absorption amine is expressed in seconds, during which a drop of Isopar G placed in the same way as in the case of maintaining the oil absorption coefficient makes transparent the entire surface (about 10 mm in diameter) of the paper placed under the drop as measured by a stopwatch. The surface roughness is determined by the Beck method according to JIS-P8119.

In the transfer step, about 20-50%, preferably about 30% t of the depth of the developer solution on the surface of the photosensitive body before the transfer should remain on the surface after the transfer of 57-49493 and, in general, a development layer 2-15 .mu.m thick should remain.

This is a necessary condition to avoid stains in the transferred images and to prevent the development of stains on the transfer material, taking into account the surface roughness and the anti-oil absorption property in the transfer material.

After the transfer, the photosensitive body is transferred to a cleaning device to remove the 2-15 thick liquid remaining on the surface of the photosensitive body.

Cleaning can be performed by pressing a blade, roller, or brush against the photosensitive body to remove any remaining solution. Cleaning should be performed so that the thickness of the developer solution is less than 1. on the surface of the photosensitive body. For this purpose, for example, a blade of polyurethane plastic p can be used at a pressure of more than 5 kp / cm.

The present invention is illustrated by the following examples.

Example 1

The photosensitive body was prepared by applying to a thick film of 60 μl a solution of 2,5-bis- (p-diethylaminophenyl) -1,3,3-oxadiazole in toluene and chlorobenzene as a photoelectric conductor, polycarbonate (trade name Tubin E 2000; sells Mitsubishi Resin Co.) as a binder resin and Rhodamine B as a sensitizer in a ratio of 1: 1: 0.015 by weight to give a film having a dry thickness of 10.

The surface of the above-mentioned photosensitive body was evenly charged with a & 5 »5 KV corona discharge and exposed with the original images to obtain electrostatic latent images. Images were developed with a commercially available liquid developer to form bright images on the surface of the photosensitive body. The developing solution remaining on the surface of the photosensitive body was about 60 μm thick. The thickness of the liquid layer was reduced to about 15 with a 6.5 KV corona discharge and then transferred in about 0.2 seconds by corona transfer to a transfer paper with an oil absorption coefficient of 135 sec. and evenness 100-120 sec. Purification was then performed with a polyurethane blade so that the thickness of the liquid layer was less than 1.

The above procedure was repeated. Each time, the results were satisfactory to obtain a clear and unambiguous copy.

Example 2

The photosensitive body was prepared as in Example 1 by applying to a thick aluminum film a solution containing 2,5-bis (p-dimethylaminophenyl) -1,3, U-oxadiazole as a photoelectric conductor in toluene and chlorobenzene, acrylonitrile-styrene copolymer resin (commercial pan -20; 9 57493 sells Union Carbide Co.) as a binder resin and sensitizer a dye of the following structural formula CH3 CHq CH3 CH0 O.ΛΪ / 3 n-C6H17 CtO . The following treatments were the same as in Example 1 and clear and clear copies were obtained.

Example 3

A mixture of 150 ml of acetonitrile, k g of cuproiodide and 30 ml of a 5 # solution of polyvinyl formal was applied to a 90 μU thick polyethylene terephthalate plate and dried to make the surface of the plate electrically conductive. A solution of 3 g of vinyl acetate resin in 500 ml was then applied to the surface to obtain a 6 μm thick dried film. The above product was further brushed with a solution having the following composition to obtain a 7 μU thick dried film, from which a two-layer photosensitive body was prepared: poly-N-vinylcarbazole 2 g 2, U, 7-trinitrofluorenone 2 mg 3,3 ', 3 "-tricarbazolylmethyl chloride 5 mg monochlorobenzene 50 mg

The surface of the aforementioned photosensitive body was uniformly charged with a +7 »0 KV corona discharge and exposed through the original images to form electrostatic latent images. Electrostatic latent images were developed with a known liquid generator to form bright images on the surface of a photosensitive body. Thereafter, the thickness of the liquid with the photosensitive body was adjusted to about 15 yu with a corona discharge of -6.5 KV, and the images were transferred to a sheet of paper with an oil absorption coefficient of 135 sec. and evenness 100 sec. This was followed by cleaning with a blade plate. The above procedure was repeated and the results were as good as in Example 1.

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Example U

Pure selenium of 99.999 Jf was coated on the surface of a highly polished aluminum drum by vacuum evaporation to a thickness of 50-60 at a vacuum of 2 x 10 nm Hg and a base temperature of 65 ° C to produce a two-layer photosensitive body. The surface of the photoelectrically conductive layer was then uniformly charged with a +7 KV corona discharge and exposed through the original images to form electrostatic latent images. The images were developed in the same manner as in Example 1 with a liquid developer to obtain bright images on a light-sensitive body. As shown in Example 1, the thickness of the liquid on the photosensitive body was adjusted to about 20 using a corona discharge of -6.2 KV, and the images were then transferred to a sheet of paper with an oil absorption coefficient of 35 sec. and evenness 110 sec. Thereafter, cleaning was performed with a rotating brush so that the thickness of the remaining developing solution was reduced to less than 1. The above procedure was repeated and obtained as good as in Example 1.

If a drum whose surface is coated with selenium by vacuum evaporation is used as a photosensitive body and the development is performed by a liquid generator, the conversion of the surface of the photosensitive body to crystallization is accelerated, which adversely affects image formation.

However, the cleaning step in the present invention, in which the thickness of the liquid in the photosensitive body is reduced to less than 1 μm with a blade, roller or brush, is likely to remove the crystallized layer together with the developing liquid from the surface of the photosensitive body. Thus, inactivation of the photosensitive body caused by crystallization can be prevented and benign images obtained.

Example 5

A mixture of 100 g of microcrystalline cadmium sulfide, 10 g of a 50 μl solution of vinyl chloride-vinyl acetate copolymer in toluene and 80 g of toluene was applied to a 0.05 mm thick aluminum foil to form a dry film thick. A 36 μm thick polyethylene terephthalate film was then fixed with an epoxy adhesive of the low temperature curing type to form a three-layer photosensitive body. The surface of the photosensitive layer of the photosensitive body was uniformly charged by a +7 KV corona discharge, exposed through the original images using a simultaneous 7 KV AC corona discharge, and further exposed to light to obtain electrostatic latent images.

11 5 7493 cyclic rubber 3 g low molecular weight polyethylene 2 g carbon black 2 g xylene 30 g was dispersed and triturated for 12 hours in a ball mill and dispersed in 1 liter of an electrically insulating liquid (trade name Isopar G) containing Ho mg of lecithin with a homogenizer to prepare a homogenizer. Using this developer, the above-mentioned electrostatic latent images were developed to obtain Kirk images for a light-sensitive object. The thickness of the developing liquid on the surface was about 60.

The next step was to perform a corona discharge of 6 U KV to reduce the thickness of the surface developer solution to 15 μm, after which the images were transferred in 0.25 seconds by the corona transfer method to a transfer paper with an oil absorption coefficient of 150 sec. and smoothness 100 sec. and the images were dried with hot air. Very bright and clear images were obtained.

After transfer, the thickness of the developing solution remaining on the surface of the photosensitive body was about 5. This was reduced to less than 1 with a polyurethane blade plate. The method was used repeatedly. The results obtained were always good.

Example 6

The zinc oxide-resin paste containing the following ingredients was applied to a 0.05 mm thick aluminum foil with a wire ruler to form a dry 18-22 μm thick coating layer. Thus, a two-layer photosensitive body was prepared.

Parts by weight

Zinc oxide-resin paste of photoelectric conductive zinc oxide 100 parts polyvinyl butyl (trade name BM-2,

Sekisuki Chemicals Co.) 375 parts of acrylic resin (trade name LR-VT2,

Nippon Reichhold Co.) 125 parts of isopropyl alcohol 700 parts of xylene 800 parts

Rose Bengale (methanol solution) 3 parts

The above ingredients were mixed in a ball mill and then diluted with a mixed solvent of isopropyl alcohol and xylene until the particle size was reduced to about 600 centipoise. The resulting mixture was brushed onto aluminum foil.

The surface of the above-mentioned photosensitive body was uniformly charged with a 77> ^ KV 12 57493 corona discharge, exposed through the original images to form electrostatic latent images. The carbon black-resin mixture shown in Example 5 was then dispersed in a homogenizer in 1 liter of electrically insulating liquid (Isopar G, sold by Esso Co.) containing 100 mg of cobalt naphthenate to prepare a liquid extractant. Using this development, electrostatic latent images were developed and bright images could be obtained on the surface of the photosensitive body. The thickness of the surface developer solution was adjusted to about 15 using a +7 KV corona discharge, and the images were then transferred by corona transfer to a sheet of paper with an oil absorption coefficient of 135 sec and a smoothness of 120 sec. wheelbase following brush cleaning. The method was used repeatedly. The results were as good as in Example 1.

Example 7

In the same manner as in Example 1, visible images were formed on a photosensitive body with a liquid generator thickness of about 60.

Thereafter, a corona discharge sweep of 7.0 KV was performed to adjust the thickness of the liquid on the surface of the photosensitive body to 5 ~ 6 μm, and the images were transferred using corona transfer in about 0.25 seconds to a transfer paper with an oil absorption coefficient of 600 sec. and smoothness 300 sec. The transferred images were dried with hot air. The images obtained were extremely bright and clear.

After the transfer treatment, the thickness of the liquid on the surface of the photosensitive body was about 3, which was completely removed by cleaning with a polyurethane blade without leaving a detectable amount of liquid on the photosensitive body.

Example 8

In the same manner as in Example 5, visible images were formed on a photosensitive body with a developing liquid thickness of about 60.

A corona discharge sweep was then performed at 6.0 KV to adjust the thickness of the liquid on the surface of the photosensitive body to 28-30 and the images were then transferred by corona transfer in about 0.25 seconds to a transfer paper with an oil absorption coefficient of 50 sec. and smoothness 50 sec. The transferred images were dried with hot air. Extremely clear and subtle images were obtained.

After the transfer treatment, the thickness of the liquid layer on the surface of the photosensitive body was about 7 μm, which was completely removed with the purifying amide with a polyurethane blade without leaving a detectable amount of liquid on the photosensitive body.

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Example 9

In the same manner as in Example 5, visible images were formed on the photosensitive body with a developing liquid thickness of about 60.

A corona discharge scan of 6.5 KV was then performed to adjust the thickness of the liquid layer on the surface of the photosensitive body to 10-12, and the images were then transferred by corona transfer in about 0.25 seconds to a transfer paper with an oil absorption coefficient of 300 sec. and smoothness 200 sec. The transferred images were dried with hot air. Extremely clear and subtle images were obtained.

After the transfer treatment, the thickness of the liquid layer remaining on the surface of the photosensitive body was about U, which was completely removed by cleaning with a polyurethane blade when the thickness of the liquid layer remaining on the photosensitive body was less than 1.

Example 10

In the same manner as in Example 5, visible images were formed on the surface of the photosensitive body with a thickness of the developing solution of about 60.

A corona discharge scan was then performed to determine the thickness of the liquid on the surface of the photosensitive body to 15, and the images were then corona transferred to a film of polyethylene terephthalate (trade name ffylar) having an oil absorption coefficient of about 0.25 seconds. («O sec.) The transferred images were dried with hot air. Extremely clear and subtle images were obtained. After the transfer treatment, the thickness of the liquid layer remaining on the surface of the photosensitive body was about 7, which was almost completely removed by cleaning with a polyurethane blade, the thickness of the liquid layer remaining on the photosensitive body being less than 1.

Claims (3)

111 57493 A continuous photocopying method of electronic photography, in which electrostatic latent images formed on a light guide and electrically insulating layer of a substrate are generated by a liquid developer to adjust the layer thickness of the developing material remaining on said layer, then the generated images are transferred from an electrostatic copier than 50 sec. A method according to claim 1, characterized in that a thick development layer 2-15 remains on the substrate after the transfer step. Method according to Claims 1 and 2, characterized in that the thickness of the developer layer remaining on the substrate is adjusted by means of a Korona scanning device before the images to be developed are transferred.