DE2025065A1 - Electrophotographic copier - Google Patents

Description

Electrophotographic copier

The invention relates to an electrophotographic copier for the production of, in particular, monochrome or multicolor Reproductions.

It is an important object of the invention to provide an apparatus with which a photosensitive copy carrier so is aligned and guided that when producing a reproduction no mutual displacement of the color separations occur, the replacement of the color separation filters and the developing rollers is controlled automatically and sticking of developer on the frame of the photosensitive carrier and a resulting coloring of the frame is avoided.

The invention provides a copier of the type mentioned with a rotatable disk or guide for holding a copy carrier and with devices arranged one behind the other above the rotatable guide for electrostatic charging, exposure, development, fixing and, if necessary, drying of the copy carrier, with one revolution of the copy carrier a single color and a multicolored image reproduction can be produced with multiple revolutions of the copy medium.

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In a device of the type mentioned, according to the invention one is a photosensitive layer of photoresistive material applied to a translucent base and one is the photosensitive layer together with the frame holding the translucent base, usable as a transmitted light image or microfilm carrier light-sensitive copy carrier arranged on a rotatable holder and set in rotation with this, so that he has a number of procedural steps, for example electrostatic charging, exposure, development, fixing and drying is subjected, wherein a monochromatic image reproduction or, if repeated, for the production of the monochromatic image reproduction applied process, a multicolored image reproduction is created without the light-sensitive copy medium holding frame receives a paint application.

Further features and advantages of the invention result from the following description of exemplary embodiments with reference to the drawing. In this one is:

Fig. 1 is an oblique view of an embodiment with a light-sensitive copy carrier according to the invention,

FIG. 2 is an enlarged end view of part of the photosensitive copy carrier according to FIG. 1 with a light-sensitive layer and a translucent base,

Fig. 3 is a sectional view of the photosensitive Layer and the translucent base according to Fig. 2,

4 shows a schematic side view of an inventive Embodiment of an electrophotographic Copier,

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Fig. 5 is a plan view of part of the device according to Fig. 4 and

Fig. 6 is a side elevational view, partly cut away, of a rotatable developing device according to FIG the invention.

To produce a light-sensitive copy carrier 4 (FIG. 1), a light-sensitive layer 1 in the form of an organic photoresist material on one consisting, for example, of polyethylene terephthalate transparent base 2 applied and the layer 1 together with the base 2 in one example Rigid cardboard frame 3 inserted. That the Photosensitive layer 1 forming organic photoresistive material is translucent, so that the finished light-sensitive copy carrier 4 is also transparent or translucent. Such a translucent copy support is suitable for use as a transmitted light image or as a microfilm carrier for projection of the image reproduction produced on it. ·

The invention provides a copier which, when using the copy carrier described above, covers exactly Color separations generated. During the copying process the light-sensitive copy carrier 4 makes a revolution in one plane. Along the circular orbit of the copy medium and various devices 6 to 10 are arranged above it. These devices are used for electrostatic charging of the photosensitive copy carrier, its exposure, development, fixing and drying. A full round of one light-sensitive copy carrier 4 results in a monochrome .Bildreproduktion. With several revolutions, a multicolored image reproduction is created.

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The -Ii rushes sensitive copy carrier 4 is on a rotatable disc 5 arranged, which is electrically conductive and has a ground connection. To hold the copy carrier 4 on The top of the rotatable disk 5 is a holder 11 provided on this.

The decoupling device 8 (FIG. 6) contains, for example, three developer rollers 12. In each case one of the rollers 12! _o ■? is in a position that it comes into contact with the copy carrier 4 when it passes through. The roller in question is driven at a peripheral speed corresponding to the speed of the copy carrier 4 or at a specific speed relative to it. The developer _{rollers 12. o z} each have a conical roller body or hollow cone 15 with fine openings 14 and a coating 16 made of a porous material, for example a sponge or the like, which completely covers the jacket of the conical roller body 15 Developer 1? each included with a different color. During the rotation of the rollers 12, which are in contact with the copy carrier 4. _{o x} of the developer 17 contained in the respective rolling body 15 exits through capillary action in the required amount. When the developer 17 in the individual orphan bodies 15 is used up, the developing device 8 is tilted in the direction of the arrow (FIG. 6), and the individual rollers receive a new developer filling after a plug 18, which normally keeps their free ends closed, has been removed.

After applying a light-sensitive copy carrier 4 to the rotatable disk 5 and securing it by means of

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ORfGtWAL INSPECTED

of the holder 11, a locking device 19 is triggered by actuating a start button (not shown). she lifts a pin 20 against the force of a spring 21 from a notch 22 formed in the edge of the rotatable disc 5 (Fig. 5) The lifting of the pin 20 from the notch 22 gives the movement of the rotatable disk 5 by means of a motor 23 free in the direction of the arrow (Fig. 5).

When passing through an electric charger 6, the entire surface of the photosensitive copy medium becomes 4- · Evenly electrostatically charged. Once the light-sensitive copy carrier 4- on it the one shown in dashed lines Position reached (Fig. 5), the pin 20 engages Locking device 19 under the pressure of spring 21 again into a notch 24 on the edge of the rotatable disk 5. Simultaneously the drive of the disk 5 by the motor 23 stops. The light-sensitive copy carrier is now in a position for exposure by the device 7

With the copy carrier in the exposure position in this way 4- a pattern or image to be copied is created Orginals D arranged on an original carrier 25 by means of light sources 26 is illuminated and projected through a color filter 27 and a projection lens 28 onto the copy carrier 4-. In order to the copy carrier is exposed to a first color separation and an electrostatic latent corresponding to this color separation Image generated on it.

After the end of the exposure, the pin 20 is lifted out of the notch 24- and the disk 5 is driven again by the motor 23 in the direction of the arrow. The copy carrier 4 moves to the developing device 8. As it passes through this, it comes into contact with the developing roller

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the electrostatic latent image being developed by means of a first color developer discharged by the roller 12 " and made visible. The copy carrier 4 then moves for fixing and drying on the fixing device 9 and drying device 10 along. if the disk 5 after a full revolution in its starting position returns (Fig. 5) the pin 20 re-engages in the notch 22 and locks the disc 5 in place the application of the first color separation ends «Deviating From the illustration in Fig. 5, the locking device 19 can have any other suitable shape or design.

When the disc 5 is in the position according to FIG. 5 to stand comes, a signal is generated by an encoder 30 arranged on the disk 5, which signal is sent by a on the frame of the copier arranged receiver 31 is collected. The signal triggers the drive of a motor 29, which then exchanges the first color filter 27 for a second one. Afterward the (not shown) start button is pressed again, so that the disc 5 the .Kopieträger 4 in the above-described Way leads along the electrical charging device to the exposure device. If the copy carrier when the exposure device 7 is reached, actuation takes place the locking device 19 for stopping or fixing the disk 5 · As a result, the copy carrier 4 is exactly in the same position Position aligned as in the previous revolution, so that no shift of the first compared to the second exposure and thus the corresponding color separations takes place.

The second exposure takes place through the second color filter 27 with a different color than the first exposure. In the process, an electrostatic latent image corresponding to the second color separation is generated on the copy carrier 4

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covers the first image with an exact fit. Then the Copy carrier 4 led to the developing device 8, in which the second latent image produced thereon by means of a second roller 12p is developed and made visible. The feed of the roller 12 ^ in the working position has meanwhile taken place is effected by a motor 32 which can be actuated simultaneously with the motor 29 to replace the color filters 27. After the development, the copy carrier 4 moves again on the fixing device 9 and the drying device 10 up to the position shown in FIG. 5, in which the disk 5 is locked. So that's that Application of the second color separation finished.

The working cycle described above will depend on multiple of the number of colors required to build the image repeated. A monochrome reproduction, for example, only requires one revolution during production an image with natural colors three to four rounds needed.

The fixing device 9 * shown has a conical one Roller 33 made of a spongy material soaked with a fixing solution, which is used to fix the developed image the surface of the copy medium 4 containing the image rolls off. Depending on the one for the transparent base 2 of the copy medium The material selected and the type of toner used for developing can also be fixed directly by heating or by means of solvents.

The frame 3 holding the photosensitive material of the copy carrier 4 is to protect against the effects of the Petroleum-based solvents are made oil-proof by the developer »However, the substances used for this have generally

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mean a high electrical resistance that causes a charge of the frame 3 could bring about. However, any electric charge contained in the frame 3 would off the toner attract the developer so that the frame 3 would receive a paint application. Therefore, the frame 3 is made of an electrical one made conductive material or made oil-proof and electrically conductive at the same time in order to allow electrical charging of the frame. 3 to avoid. On the other hand, such an electrically conductive frame 3 acts during the charging of the Copy carrier possibly as a shield, so that parts of the photosensitive layer adjacent to the k frame are insufficiently charged or not charged at all. If the above The mentioned oil proofing and making conductive does not completely exclude an electrical charge of the frame 3, this can after charging, but before exposure, in contact with an electrically conductive part connected to ground are brought so that any in the frame 3, so on the non-image bearing surfaces of the copy carrier 4, removed will. However, parts of the electrical charge remain in the smallest depressions in the not completely smooth surface of the Frame 3, which cause the toner to adhere.

To avoid these disadvantages, according to the invention, the P frame 3 is first coated with a photoresist material or soaked. Then the entire frame is illuminated during the exposure to remove any electrical charge, so that the toner can no longer adhere to the frame 3 and color it.

In order to achieve this, the original support table 25 (FIG. 4) has a glass plate 25 * , the dimensions of which correspond to the size of the part of an original D to be reproduced. Around the cutout formed by the glass plate 25 ^

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extends, a reflector surface 25p, which with whiter Paint, a bare sheet or the like. Is coated. if now the template D for projecting the image to be reproduced through the color filter 27 and the lens 28 the light-sensitive layer of the copy carrier 4 is illuminated by means of the light sources 26, occurs (part L of the light on the frame 3 of the copy medium 4 without the need for dedicated lighting equipment are. The same result can be achieved in that in the reflectors 26 ^. of the light sources 26 openings are provided through which light falls on the frame 3. It is also possible that the copy carrier 4 has no frame 3, but only consists of the libht-sensitive material. In this case, the elimination takes place unwanted electrical charge by illuminating the parts of the copy medium that are not to be provided with the image

In the inventive method described above direction of the copy carrier is guided only in one direction along its circulation. This makes the control extraordinary facilitates and avoids misalignment in multicolored reproductions. By changing the 3-color filter and the developer rollers by means of the on the copy carrier leading disc and the receiver located on the fixed part of the device is controlled, is a reliable and trouble-free operation.der according to the invention Device guaranteed. Finally, there is the adhesion of developers to the frame of the photosensitive Copy carrier by illuminating the frame by means of part of the light generated by the light sources and through voxaufende coating or soaking the frame with buckets Photoresist material for sure prevented.

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Below are examples of using the invention Device usable photosensitive copy carriers listed.

1) As a transparent, organic poto resistor material condensed aromatics such as anthracene, carbazole, anthraquinone and perylene are suitable for the light-sensitive layer 1 or the like, heterocyclic compounds such as aoylhydrazone derivatives, Triphenylpyrazoline derivatives or the like, also polyvinyl carbazole or the like

2) The polyester material commercially available under the name Mylar is suitable for producing the transparent base 2, Glass or an acrylic acid resin. When using The frame 3 can be dispensed with glass or an acrylic acid resin which is rigid per se. By appropriate treatment of the base 2 to produce their electrical conductivity, fogging during reproduction can be prevented.

3) The frame 3 is made of stiff paper, for example.

4) To make it oil-proof and conductive, the frame is coated or impregnated with one of the following substances, for example: copolymers or mixed polymers of acrylic acid and acrylic acid ester, of vinyl acetate and crotonic acid or of styrene and maleic acid, water-soluble vinyl resins such as polyacrylic acid, polyacrylamide, polyethyleneimine, polyvinyl alcohol, Polyvinylpyrrolidine or the like, water-soluble cellulose derivatives such as carboxymethyl cellulose, methyl or ethyl cellulose, animal or vegetable protein such as gelatin or casein, viscous plant substances such as gum arabic or sodium alginate, inorganic . Niche salts such as sodium chloride, ammonium chloride, potassium chloride, calcium chloride, sodium nitrate or the like, various activators, quaternary polymers of ammonium salts such as poly-N, N-dimethyl-3, 5-methylene) piperidine chloride, poly (vinylbenzyltrimethylene ammonium chloride).

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Claims (7)

Patent claims Electrophotographic copier for producing in particular single or multicolored reproductions, characterized by a rotatable disk or guide (5) for holding a copy carrier (4) and by devices (6 to 10) arranged one behind the other above the rotatable disk or guide (5) for electrostatic charging, exposure, developing, fixing and, if necessary, drying of the copy carrier, a single-colored image reproduction being able to be produced with one cycle of the copy carrier (4) and a multicolored image reproduction with a repeated cycle of the copy carrier. 2. A copier according to claim 1, characterized by a locking device (22,24) movable into engagement with a locking device (22,24) which is arranged on the rotatable (5) ″ located copy carrier (4) this is locked in each case in the same starting and exposure position for precisely fitting a multicolored image reproduction by engaging in the locking device (22,24). 3. Copier according to claim 1 or 2, characterized in that the exposure device (7) has a table (25) for a template to be copied (D), "light sources (26) for illuminating the template (D), color filters (27) and Has devices (29) for changing the color filters and that in order to generate a multicolored image reproduction by means of signal transmitters and receiving devices (30,31) assigned to the rotatable guide for each revolution of the copy carrier (4) the changing of a color filter (27) can be triggered against a different color., 009850/1844 - 12 - 4. Copier according to at least one of claims 1 to J, characterized by means for illuminating the frame (3) of the photosensitive copy carrier (4) after electrical charging to remove the electrical charge of the frame. 5. Copier according to claim 4, characterized in that a reflector (25p) on a part of the table (25) for the original to be copied (D) is provided as a device for removing the electrical charge of the frame (3) of the copy carrier (4) - Is on which a part of the light of the light sources (26) of the exposure device (7) directed onto the feed table (25) falls. 6. copier at least according to claim 4 or 5 » characterized in that the copy carrier (4) has a coated or impregnated frame (3) coated with a photoresist material and a light-sensitive layer held by this, preferably consisting of organic photoresist material (1). 7. copier according to at least one of claims 3 to 6, characterized in that the developing device (8) "has a number of, for example, hollow-conical rollers (12, - _ox ) which are arranged on a rotatable holder (13; and can be moved into their working position on the rotatable disk or guide (5) by means of a motor (32) can be operated simultaneously with the motor (29) for exchanging the color filter (27). 009850/1 Blank page