DE1937488B2 - Electrophotographic process and apparatus for the production of Teilfarbenladungsbil the - Google Patents

Description

Ii

is developed with red toner and the developed charge is lifted from the insulating layer. In the JiId or the like superimposed on the copy paper. photoconductive layer becomes a permanent inner

The result of this hitherto customary, similarly generated at- polarization. A partial color image production, for example described in OS-VS 3 376 133, is also not possible with this method.
The method is that the black δ obtained in this way is the object of the invention to make the known search letters illegible and dirty. Process to avoid inherent disadvantages and if a color shift takes place, which is caused by a reproduction of an imprecise overlay of the red clay image on the correct color part of a multicolored copied black color image with the least effort It is difficult to effect and bind such shifts in an extremely simple manner, since this enables an exact position correspondence, a multicolored, the original mung at the time of transmission is necessary, which exactly and true to color reproduction of a high mechanical precision and correspondingly to produce a multicolored original «,
requires the effort. Another disadvantage exists in an electrophotographic process of the single

in that, according to the invention, the color rendering is not sufficiently cited above takes place because the red toners see that first an imagewise exposure in on the black Letters is applied. The color control of the partial color to be reproduced takes place and becomes influenced by very complex factors, if an image-like closing during the transfer this process applied to natural color photos to the exclusion of the exposure to be reproduced will. Since, for example, to reproduce a dark 20 partial color takes place.

red image a thick red clay image a dik- The invention creates e ^ i electrophotographic

If a black image is superimposed, there is only one method with which such parts of a red or black image are reproduced when the applied multicolored master copy is reproduced. Toner is opaque. This is particularly true of those having a predetermined color, however, in the case of business papers, documents and the like, the 25 repetitions of the copying process for each of which consist largely of black letters. Ent- original colors their color-true reproduction or holds such, to achieve predominantly from black book duplication,
The structured document would have a natural color. So far, a partial color exposure was either

photo, the user does not have to provide for the black book or, as in the case of rods, because of the presence of the natural Carlson process, a partial color image must at most take a color shift in KEiuf in the color photos. photoconductive layer with toner overlay and Furthermore, with the known method of corresponding color distortion and / or blurring, it is not possible to only take a certain color part into account,
to reproduce a multicolored original. It is true that US Pat. No. 3,057,720 deals with the

The US-PS 2,297,691 describes the Carlson-Xe 35 multicolor xerography by multiple color plate-imaging processes, in which a photoconductive layer (red, green, blue) of a xerography plate with fotoauf exposed to a conductive support. In the case of a conductive layer on a metal support and through a tul color exposure through a filter, generation of the subtraction colors in the electrostatic winding and subsequent repetition with other see, developed with magenta, cyan and yellow powder Partial color or other partial colors, followed by an image. In this way one achieves a better penetration Overlaying of the toner image creates a retention of the partial color image coverage because the multi-color multi-color copy. However, this always shows color verbs already in the BehcMungs-, not just Distortions as well as blurring because the image is photoconductive in place in the image transfer stage of the process Layer is created and the toner over- finds. An exposure of one with an isolating one storage leads to unclean color formation. 45 recording material provided with an outer layer

The invention is based on the older applicants but is complementary color intensity compensation fertilize DT-OS 1 522 567 and DT-OS 1 522 568. also here neither intended nor without further ado These concern electrostatic copying by means of possible.

of a recording material that has a base layer In contrast, the electrostatic copying

(= Carrier), a photoconductive layer and an iso- 50 process according to the invention, the projection of a having lating cover layer, the latter having an image of a desired color, that is, a partial color alternating current primary charge obtained and then benbildes, from a multicolored master copy at the same time with an imagewise exposure through a filter on a recording material a DC charge opposite with an insulating cover layer over a photo-polarity is reloaded. A partial color image-Er- 55 conductive layer in front. This image projection can However, generation is not considered here before, during or after a primary recharge with these older methods no longer find any. Then one is projected colored copies can be produced. Partial color image of the master copy by a for the

In DT-OS 1 497 164 and 1 497 169 are desired color impermeable filters on the It has been proposed to drive the last recorded material, and at the same time with named older procedures are quite similar. This is a secondary recharging or recharging. Through this he inherited becomes the insulating layer of a corresponding up- put one in a simple manner and without the slightest drawing material without exposure through an electrical blurring a compensation of the difference in intensity Field charged and then at the same time the exposure with the desired color and reloaded imagewise exposure. 65 with light of the other colors, i.e. complete

A transparent element up to the copy density is used for the primary load. The developed intensitrode (The counter electrode is the base layer = the true partial color copy can as a result Träeeri which during the secondary change or open without color distortion and / or blurring with other

5 6

ren. Partial color images produced in the same way is in other processing stages

for a multicolor copy of best color quality, use a different filter 5. that for colors other than that

be agreed. color to be reproduced is permeable, e.g. for

According to the invention it is possible to choose other colors than red (Fig. IB. 3B. 4B). Under- and very conveniently a predetermined color rendering 5 half the filter 4 or 5 is located as a corona to win a multicolored master copy. primary loader 6 or This corresponds to the multicolored copy of the re-a secondary line 7th either as an alternating current output True-to-color: it has no color mismatch, discharge path or as a direct current opposite a multicolored master copy, if the work is carried out in the opposite direction to the primary charge copying process according to the invention as often as necessary polarity can be implemented. The recording was repeated. In addition, there is a sealing material P in the embodiments For example, it is possible to reproduce a dark red image according to FIGS. 1A, IB and IC as well as FIGS. 4A, 4B adorn, with the reproduction of the dark red color and 4 C each from a base plate 10, a photo is achieved is made by applying a thin red clay image to a conductive layer 9 and transparent insulating thin black toner image without the use of a 15 top layer 8. Its surface becomes primarily positive semi-transparent toner is superimposed. charged by means of the translucent primary

An embodiment of the invention according to the invention. Its shielding 6, (Fig. 1 A) consists of

Driving can consist in the fact that after the picture-a transparent material or is optically free above

embossing the recording material with its gan (shielding plate 13. Figs. 5 to 7). At the same time with

zen surface is exposed. ao the primary charge or afterwards the pictorial

For making a copy of a multicolor exposure of the same surface. This can be done with-

gene master copy using one after the means of an optical reflection device, means

Method according to the invention treated recording a transmitted light device or another

tion material sees a further development of the invention known and therefore not in the drawing

dung before. that the latent image is developed and that the device represented takes place,

Finally, an image that corresponds to the image with the areas of the recording material P to be reproduced

corresponding color, on the copy material falls due to the filtering with the red filter 4 only the

is transmitted. The processing stages of the production red portion of the light emitted from template 1

generation of the latent image on the recording material. The exposure has the consequence that the reflection

material and possibly also the exposure se ^; ner 30 stood the photoconductive layer 9 decreases and that

entire surface, furthermore the development of the la- a polarity opposite to the primary charge

tent image as well as the transfer of the image, i.e. negative charge on the back of the image

occurs with the BiI insulating cover layer 8 corresponding to the color to be reproduced,

des can for the purpose of obtaining a multicolor copy. On the other hand, in areas b of the

for each color of the multicolored master copy 35 red image 2 outgoing light through the red filter

be repeated. through onto the recording material P. Similarly

A device for carrying out the invention as in the areas α is on the rear surface of the method according to the invention is characterized in that the cover layer 8 generates a negative charge,
the recording material from an insulating Tn dei! Areas c , however, does not meet any light on the cover layer, a photoconductive layer and 40 photosensitive carrier P. since the color image 3 consists of a base plate which is electrically conductive black and therefore no light emanates from it and / or has insulating properties, and that the The resistance of the photoconductive layer 9 therefore does not decrease for the primary charge and for the secondary Umla-, and there is a corona discharge path on the back of the cover. layer 8 no negative charge occurs. The same thing

The invention is carried out on the basis of the following when the color image 3 differs from red

Writing of exemplary embodiments with reference colors, for example blue, since that depends on the color

taking on the drawing explained in more detail. Figure 3 shows light emanating through the red filter 4 absor-

F i g. 1 A, 1 B, 1 C Explanatory schemes for a beer is.

Embodiment of the electrofo- In this way it is achieved that the primary

graphic process, 50 charge opposite, i.e. negative charge

F i g. 2 schematic top views of the invention on the back of the insulating cover layer 8 de;

according to color copies in different processing recording material P in the areas ι

levels, and b, but not in areas c.

Fig. 3A, 3B, 3C and Fig. 4A, 4B, 4C Er- The imagewise exposure can instead of medium!

Refinement schemes of further embodiments of the filter, also with monochromatic light

The electrophotographic method according to the invention take place at a wavelength which is to be reproduced

and matches the color.

F i g. 5 to 7 schematic side views of Once the method steps described abge

Parts of a device according to the invention. are closed is done on the recording mat

The schematic drawing allows a multi-color P through the filter i, which is impermeable to red light

Bige master copy 1 recognize that a color image 2 an imagewise exposure with the multicolored

with the color to be reproduced, e.g. B. Red, and a master copy 1, at the same time with the Se

Another color image 3 carries, which is a different than the secondary discharge or transfer by means of the Sekun

color to be reproduced (e.g. not red). därladers7 (Fig. IB, 3B, 4B). The secondary la

Between the multi-colored template and a 65 der7 can either be used as a direct current discharge path

Recording material P is a polarity that is only used for the opposite direction to the primary charge

Color-permeable filter4, e.g. a Rotfil or alternating current discharge path

ter, arranged (Figs. IA, 3A, 4A). Be at this det. Its shield 7, (Fig. IB) or 12

^ F i g. 5 to 7) is optically free at the top. Fig. IB shows ian arrangement in which an alternating current discharge path is used as the secondary charger 7.

In the areas α, light emanating from the original 1 and other, non-red light passes through the Filter 5 through to the recording material P. When light falls, the resistance of the photoconductive decreases Ski lift 9 from, and the negative charge that is on the back of the cover layer 8 was present, together with the positive charge on the Front removed.

In the areas b , the light emanating from the color image 2 is intercepted by the filter, so it does not reach the recording material P, and the resistance of the photoconductive layer 9 does not decrease. The negative charge present on the back of the cover layer 8 is therefore not extinguished, even if the secondary charger or discharger? is active, and it retains its attraction to the positive charge on the front. The effect of the discharge or charge reversal is greatly reduced as a result, and the positive primary charge on the front side of the insulating cover layer 8 is largely retained.

Since no light emanates from the color image 3, no light reaches the recording material P. in the areas c and the resistance of the photoconductive layer 9 does not decrease. However, because no negative charge was generated on the rear side of the cover layer 8 at the time of the primary charge, the discharge effect is not interrupted and, as a result, the positive charge applied to the insulating layer 8 is eliminated.

After the process steps described, the entire surface of the recording material P is exposed to radiation to which the photoconductive layer 9 is sensitive (FIGS. 1C, 3 C, 4 C). As a result, the charges not influenced by the charge state of the insulating cover layer 8 are discharged, and the electrostatic contrast is increased.

The latent image formed is then developed on the recording material P, as shown schematically in Fig. 2 is shown. From Fig. 2 (I) it can be seen that when using a color toner or an offset base toner of the same color as the color image is transferred to the copy paper or material 11 takes place. It is therefore possible to choose a specific one from the multicolored master copy i Color 2 can be reproduced.

The recording material P can be constructed as follows. The base plate 10 can consist of aluminum and, as the photoconductive layer 9, have a selenium film vapor-deposited at about 60 ° C. up to a thickness of about 30 μm, on which an approximately 25 μm thick polyester cover layer 8 is applied. In another embodiment, the recording material P also consists of an aluminum base plate which has been brought to a temperature of about 58 ° C. for vapor deposition. The photoconductive layer 9 was at about 250 ⁰ C to 350 ° C in a vacuum of better than 10- 'Torr to a thickness of about 50 μΐη of a material is evaporated, that by about three hours melts at about 500 ° C of 90% Se, 10% Te and small additions of Ge, about 0.04 to 0.5%, had been recovered. A polyester film about 25 µm thick was applied to this by means of an epoxy adhesive. The surface of the aluminum base plate 10 was oxidized before the vapor deposition.

Excellent results were obtained with both embodiments of the recording material P. The recording material P, which consists of three layers, has semiconducting properties which lie between the n and p conductors. Its specific resistance is in the order of magnitude of ίο ΙΟ ¹ · ¹ Ohm · cm, and positive or negative DC voltages of up to above 500 V can be applied to it.

In another embodiment of the invention, the recording material P 'also has the three-layer structure mentioned, but in this case the base plate can additionally have an insulating layer. When using this carrier, it is sufficient for charging or discharging according to the method described above to place the recording material P 'on an electrically conductive plate or to apply electrical voltages of different polarity from both surfaces. A four-layer material P ', the base plate of which consists of an insulating layer 1O ₁ and an electrically conductive layer 1O ₂ (FIGS. 3A, 3 B, 3 C), can also be used. can be used instead of the three-layer material P.

The insulating cover layer present in the recording material according to the invention can consist of organic and / or inorganic insulating materials, which have the ability to store charge exhibit. For the electrically conductive layer, metallic materials, paper and other electrostatically conductive materials are used.

The structure and mode of operation of the embodiment P 'of the recording material are as follows on the basis of Fig. 3 A, 3B, 3 C under the same. Conditions as in FIG. IA, IB, IC explained. As can be seen from Fig. 3A, the recording material becomes P 'exposed either simultaneously with the primary charge or imagewise afterwards. Just the light transmitted by the filter 4 reaches the recording material P ', and the part of the photoconductive layer 9, which corresponds to the irradiated area, is as in FIG. 3 A shown charged. Subsequently, a secondary charge reversal takes place during the imagewise exposure through the filter 5 or AC discharge, and the resulting state of charge is shown in Fig. 3B. After completion of these processes, a radiation to which the photoconductive layer 9 responds, irradiated on their entire surface, if and as far as there is a need, the electrostatic Increase contrast according to FIG. 3C.

The last-described four-layer material P ' can be constructed as follows. On an electrically conductive base plate 10 made of aluminum, for example by means of an epoxy resin adhesive, a polyester layer of about 6 inns thickness is applied. This is up to a thickness of sth; 50 μm coated with a layer of copper-activated CdS particles with a diameter of about 10 μm using cellulose acetate as a binder. Finally, it is-adhesive resin by means of an epoxy, a polyester film of about 20 thick applied to the insertion of the insulating layer 10 _t ei enables dit. Use of high-sensitivity photographic material

409 532/3

Capable of materials previously used for a photoconductive filter like that. "ie a blue filter. Serve for development

Layer is not a yellow toner because of its low resistance. That by means of the yellow toner

could be used. At the same time the dielek- developed image is also applied to the already au

tric strength increased, so that damage to the copying material mentioned existing Bile

Recording material P ' as a result of an insulation fault 5 transferred and exactly superimposed,

lers or breakdowns can be avoided. Fig. 4 Finally, the cleaned recording tape

shows explanatory schemes of an embodiment material P by the primary charger 6 below overall

of the method according to the invention, charged as secondary exposure, whereupon by means of the Se

The discharge is a direct current corona discharge secondary discharge 7 is an alternating current corona

stretch with the opposite po- to charge to the primary charge at the same time as the image-wise exposure

treatment is used. FIGS. 4A, 4B, 4C correspond to being carried out without a filter. After exposure de

each Fig. IA, IB and IC. The electrostatic image will exist on every surface

but differences in the state of charge of the recording with a black toner developed and on which he

tion material P, and the electrostatic copying material formed here in a very similar manner.

see picture has transferred or superimposed in the lighter areas (background 15 described,

reason) the original has a higher potential than in the end, that is ge on the copy material

darker areas. formed toner image fixed in a suitable manner, ζ. Β

From Fig. 4 B it can be seen that the area b after the process of heat setting. All in all

has a state of charge which has been generated from such a sheet of color copy

the Fig. IB differs. When using the second 20 the four exactly superimposed color images are created

där-reloading is holding the process through the negative.

Charge disrupted, which at the interface between- Regarding the properties of the photoconductive

see the photoconductive layer 9 and the cover layer 9 of the recording material P and P 'nacl

layer 8 is imprisoned. Only that of the primary of the invention is desirable if the specific

Charge arising positive charge is eliminated, "5 resistivity greater than 10 ohm-cm ^I0, preferably comprises

and the surface area of the insulating cover layer 8 is more than 10 ^µ ohm-cm both of the positive Ko

either not at all or only slightly, as well as with the negative corona

the. charging in dark areas. The her

A multicolored reproduction of a common photoconductive layer is therefore necessary

To obtain a colored master copy 1, it is sufficient, depending on the polarity, and is sufficient

however, a gene corresponding to the respective color often does not give good results. In order to now

Using filters and achieving the same process as more properties is according to the inventor

described above according to the number of dung the insertion of an insulating layer or one

colors to be reproduced. Barrier layer provided, blocking the flow of the La

In one embodiment for another 35 fertilize between the photoconductive layer 9 unc

Application, namely in connection with blue as the electrically conductive base plate 10 inhibit

color to be reproduced in a multicolor image is or is prevented. You can also do this by ver

first applied the cyan and then the red filter. use real semiconductors. Likewise sine

A cyan filter (impermeable to red) makes it possible to use substances that have an internal polarization

the imagewise exposure of the 40 mentioned above. Materials are particularly useful

Three-layer material P simultaneously with the up- with a wide range of spectral sensitivity. Ge

charge by the primary charger 6. Then, CdS, CdSe, ZnO, ZnS, PbO are particularly suitable

at the same time as the image-wise exposure to anthracene, etc.

the red filter 4 by means of the secondary discharger 7 becomes a for the corona discharge paths 6, 7

AC corona discharge performed. Then 45 according to the invention preferably tungsten wire 12 be

the entire surface is exposed. That uses, whose diameter is around 0.05 to 0.10 mn

electrostatic latent image formed in this way lies. Also other charge or discharge before

is developed using a cyan toner. Corresponding devices can be used, e. B. Discharge

according to a conventional developing method. pins, needles and the like. Are primary loaders 6 and seconds

The developed image is built up separately from one another on 50 därlader 7 using suitable means, wi (

transfer a copy material. The recording F i g. 5 shows, each of them carries one of the filters

material P is cleaned and then by exposure or 5.

discharged over the entire surface. Another possibility of the structure is in Fi g. (

Next, the recording material P is shown, with the two corona discharges

charged by means of the primary charger 6 and with the 55 lines 6, 7 are connected to form a unit, mi

Template 1 through a (for green impermeable) Ma- which the filters 4, 5 aligned ver

centafilter exposed imagewise. While are bound. Such a unit can be convenient

then the same imagewise exposure by a handle as a device in which the Ko

Green filter takes place through, is using rona discharge paths 6, 7 and the filters 4, 5 of

of the secondary discharger 7 an alternating current corona 60 are constructed separately from each other,

discharge carried out. This in turn is followed by primary charging and pictorial loading

Exposure of the entire surface and development not at the same time, so it is useful because

treatment of the latent image with a macenta toner. Red filter 4 between the Kuron ^ discharge lines

After that, the position of the images has to be arranged in precise corners 6, 7, as shown in FIG. 7. advantage

attuned, the image on the 65 is also, two filters of each complement

transfer the above-mentioned copy material. tary color in a frame

This process is repeated again, but preparing such frames for the individual colors

this time with a yellow (impermeable to blue) yellow. The respectively required frame is then ii

the upper part of the corona discharge paths either inserted manually or automatically.

If the corona discharge sections 6, 7 and the filters 4, 5 are combined to form a unit, the upper surface of the corona discharge sections must be made air-permeable. It is particularly advantageous to provide a light-permeable, electrically conductive layer which is connected within the filters 4, S to the shielding plate 13 of the corona discharge paths 6, 7. The alternating current corona charge can be carried out very effectively as far as the recording material P or P 'if insulating layers with a thickness of about 50 μm to 200 μm, for example made of polyester film, and a transparent layer

Insulating layer within the aforementioned shielding plate 13 or the aforementioned translucent electrically conductive layer can be arranged.

Another possible embodiment is to place the filters 4 or 5 in the light path for illumination of the master copy 1 instead of putting it in the light path of the optical path emanating from the master Insert image.

All from the claims, the description ίο and the features shown in the drawing and Advantages of the invention including constructive! Details, spatial arrangements and procedural steps can be essential to the invention both individually and in any combination.

For this purpose 3 sheets of drawings

Claims (14)

Claims. 30th 35 40 1, Electrophotographic method of manufacture of partial color charge images based on a multicolored master copy on a recording S tion material with a photoconductive slide and an insulating cover layer, in which the Top layer charged, then exposed imagewise with a partial color of the original and is exposed to an axo during the imagewise exposure, characterized in that that initially there is an image-razor exposure in the partial color to be reproduced and then, during the transfer, an image-like exposure to the exclusion of the partial color to be reproduced. 2. The method according to claim 1, characterized in that the imagewise exposure with the color to be reproduced takes place simultaneously with the primary charge. ao 3. The method according to claim 1, characterized in that that the imagewise exposure to the color to be reproduced after the primary charge he follows. 4. The method according to any one of claims 1 to 3, characterized in that the multicolored Copy master illuminated with monochromatic light of the partial color to be reproduced in order to carry out the first imagewise exposure with the ι ·· partial color to be reproduced. 5. The method according to at least one of the preceding Claims, dadur 'λ, that after the imagewise exposure the Recording material is exposed with its entire surface. 6. The method according to any one of the preceding claims 1 to 5, characterized in that the secondary charge reversal takes place as a direct current corona discharge, the polarity of which is the primary charge is opposite. 7. The method according to any one of the preceding claims 1 to 5, characterized in that the secondary charge takes place as an alternating current corona discharge. 8. Device for performing the method according to at least one of claims 1 to 7, characterized in that the recording material (P) consists of a base plate (10), a photoconductive layer (9) and an insulating cover layer (8). 9. Apparatus according to claim 8, characterized in that the base plate (10) of the recording material (P) is electrically conductive. 10. Apparatus according to claim 8, characterized in that the base plate (1O ₁ , 1O ₂ ) of the recording material (P ') has insulating properties. 11. The device according to claim 8, characterized in that the base plate of the recording material (P ') consists of an insulating layer (1O ₁ ) and an electrically conductive layer (1O ₂ ). 12. Device according to one of claims to 11, characterized in that each has a corona discharge path (6 or 7) is provided for primary and secondary reloading. 13. Apparatus according to claim 12, characterized for the secondary charge S & ^^^ available opposite the prfm & r charge ΐΓ Device according to claim 12, characterized 14. ^v ? "^; ^Mi Zß _m dje secondary transshipment ffÄsl discharge section (7) pre- Exercise according to one of the claims to 14 characterized in that the first 5mjΓ an- »rΓ exposure in the one to be reproduced for the {Se * Ä filter (4) and the mr this color impermeable F, ilie _{£ V} j0 .jefur these t-aro _{areas of} the Pnmarladers deTseSärumladers (7) arranged Execution according to one of Claims 12 Td d? S Sr this color not permeable filter ⁽⁵ \ rÄ? ^D d Aüh 12 rÄ? htun _g of any one of claims 12 to 17 characterized in that "Pnmarlader? and Sekundärumlader (7) are connected by means of a frame which the permeable for reproducing color filter (4) and since ^ Mr this color is not permeable filter ( »Contains and is attached to the upper surface of the secondary loader (7). The present invention relates to an electrofotch Experienced and a device for producing Hpr Vorläse Di auiamg "> ·" <· --- bHdäßVge ^S n exposure to a reloading ^W1 A precaution that has been customary in electrophotography up to now for the reproduction of such multicolored forelegs - for example fchwar / S letters surrounded by red frames - consists in the uniform charging of a light-sensitive carrier using the photoconductive layer, in the production of a latent B corresponding to the black letters, vermitte.s the imagewise exposure through a red filter, in the development of the latent L of B by a black toner and the anschhe-in power transfer of the developed image on m PapJe and the like Sodlnn ⁸ wiid the photosensitive plate cleaned and charged or discharged. An image corresponding to the red frame and black letters is created by applying the bicarbonate exposure through a red-opaque CyanMter. The latent image created in this way becomes with