DE1597884A1 - Method and device for image generation - Google Patents

Description

₉ ..νηηΐΗΙΙΗ, ul. IHJJ. Λ. IfflCKfflS '

Dipl. Ing. H. Weicknunn, Di _- = I. Phys. Or. K. Fir: 1597884 Dipl. Ing. FA Wetckmann, Dipl. Chem. B. Hut I MünchM 27, Mfihlitr. 22nd

Rank Xe vox House-33o, Sub do .w.A'i
• L ü Ii d υ Xi, 11 / ". 1

Image generation method and equipment

The invention relates generally to xerography and

in particular on a method and a device for image generation, which prevents the transfer of toner powder to areas of the xerographic copy that do not belong to the image will.

In the xerographic process, as described in US Pat. No. 2,297,691 , a xerographic image surface in the form of a photoconductive insulating material layer, which is applied to a conductive substrate, is used to record electrostatic images. Kormalerweise the method is that the xerographic image plate -and- charged uniformly electrostatically on its surface is then exposed to a light image of the end-to Biläes reproducible, is derived whereby the charge in the expose Le "FlächenLeilöu -ler pliotoleitfähigen layer. The non-discharged parts of the layer form an electrostatic

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charge image which, in its configuration, corresponds to the original image is equivalent to.

The electrostatic latent image can then be deposited a finely divided electrostatically attractable substance can be developed using a synthetic resin powder. That Powder is held by the electrostatic charges of the layer on the surface area belonging to the picture. At the Instead of the strongest charge, the greatest amount of developer

substance is deposited, while at the point of slightest charge there is no Developer is deposited off. That way, in a a powder image corresponding to the projected light image distribution generated. This is then put on a sheet of paper or a transferred to another document and placed on it to form a permanent Fixed pressure.

The electrostatically attractable developer, which is generally used in xerography, consists of a pigmented synthetic resin powder, which is referred to in the filling as "toner". In order for the toner to bind itself to the electrostatic charge of the partial area parts, it is first necessary to charge the toner particles with a charge that is polarized in the opposite direction to the image charge. ,

In the most common method of development, caaccation development, the toner is mixed with a coarse, granular substance, the so-called "carrier ¹¹ ". The carrier usually consists of grains of glass or sand, which are "a" substance

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are absorbed, has the smell triboelelct number of the toner at a distance, so Dafi waste away the powder and the granular carrier particles with mutual f _e chselwirkung a triboelectric charge is generated. This charge causes the toner powder to adhere to the carrier particles. If the carrier material adhered to the toner is brought into contact with a latent electrostatic image, the toner is drawn off from the carrier particles by the charge of the image surface parts, whereby the latent electrostatic image becomes visible .

When performing xerography, the toner powder is often deposited on parts of the xerographic imaging plate that do not belong to the image. The main cause of such unwanted debris

are uncontrolled toner clouds and incomplete removal of the Toner not used for image development.

Uncontrolled toner clouds occur when carrier particles contaminated with toner fall onto a photoconductive film and these are cascaded. The length of impact between the developer and the photoconductive surface cause a separation of substantial amounts of toner powder from its carrier particles. This toner powder then forms a cloud-like mass which is deposited in an undesirable manner on all surface parts of the photoconductive surface, including the surface parts not belonging to the image. This property of Kaskadierungsentwicklung is exacerbated when a high Tonerkonzentratiön is used, ie if werdsn too much! Singeing toner particles with a smaller ^ close lägerteilchen mixed.

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The developer substances are discharged after they have been separated off the toner powder on the picture parts. The early particles move eich over the äohen and te- stirrings, which are afflicted with toner, and bind those toner particles that are held on the photoconductive surface by weak electrostatic forces will.

Weak electrostatic forces are characteristic of the

the toner powder in the areas not belonging to the sub-picture the 'holding attractions. Therefore, the perform / Trl-

gertsilchen a distance dta toner powder, which in the un Wise deposited in the parts of the surface that do not belong to the image became. Incomplete removal occurs when not enough toner-free carrier particles are moved over the image surface. This background build-up effect is made worse by too much toner on the carrier This results from the fact that such toner particles only after have been freed of their toner for a long time, let them remove the toner which does not belong to the development körusn.

Except for the reasons of toner deposition described above On parts of the surface that do not belong to the image, such a deposit can also be caused by toner particles are charged opposite polarity to the desired polarity. These toner particles are then removed from the image area parts repelled into the parts of the surface that do not belong to the image. That . Toner powder can also adopt a neutral polarity, so that

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also because of this "in" deposit on not belonging to sub picture t «il« n BBgliokt i * t.

The present discovery avoids the harmful effects ▼ OH In parts of the platelet that do not belong to the sub-picture, a developed Image ·· deposited toner particles regardless of their polarity, Find out the type of deposit you have or the development used.

of the invention becomes dl * bit imaged photoconductive flee immediately after developing a slight lorona charge auegeeetat. Duroh correct «selection of polarity and the strength of the charge that removes the background deposits can then appear on the surface parts that do not belong to the sub-picture existing toner powder can be charged to one polarity as a whole

the

opposite to those / toner particles in the image area parts. This will be without deterioration of the ole en · Toner · reached · on parts of the image ·

The difference in polarity of the toner powder that results In the picture surface parts and the flat parts parts that do not belong to the sub-picture Baoht-e · BÖglioh, Bittele ae Jildtransmission corotrons mar i «a foner of the lildflaehemteile sm tttransmitted end iaait one ύοά Inground deposits for ·! · lopie su received. Dar folarl-

tlteuntereohied also enables bit «ln« a to be transmitted correctly ni $ opposite polarity dl · tTtransmission of the toner parts

au

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^ r and debris free picture aurüekbleiet. Dl * the former Terfahrenart can easily be started with already existing xerography machines that work continuously and automatically. be turned. The "broad type of procedure is for lerodruoke, Xerographic printing plates and lithography suitable * These application possibilities of the rorlitgendtn invention are only Execution examples, because the finding can be done round-the-clock be used throughout xerographiechen feohnik *

With the invention, a clouding of the xerographic copying is achieved, which in the avoidance of undesired background deposits in xerographic copies and printing plates or in a division of the toner transfer consists of parts of the surface that do not belong to the image on other image substrates. All of the parts of the surface that do not belong to the picture Toner powder is set to have a polarity opposite to that dee toner powder · the image area parts of a developed xerographic image are charged, causing the transfer only ) of the toner pulverizer of the desired polarity from the developed image to another image carrier. Is accordingly it is also possible to remove unwanted toner powder from leroprinting plates.

These as well as further measures are verified according to the present invention by the developed xerography in the image area is moved past a weak corona discharge device of a polarity opposite to that of the toner powder deposited in the image area parts. This process causes

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a charge of the toner »in the not belonging to the picture Fliehenteile "of a polarity opposite to that of the phone in the picture surface parts, whereby the transmission only the · * · foaars or la «veined trap the transmission lediglis» dta phone not belonging to the picture is made visible, whereby eidh Yok background deposits free copies baw. Image plates result.

For a better understanding of the invention and its further ones

eels and gate parts are used in the following description based on the

Figures · Sa seigent

FIG. 3 shows three cross-sections of a xerographic imaging plate, the gea & e of the invention is dealt with,

tig · 4 bit 7 cross sections of a xerogrsp Make image disk that ν geat · a »wide development · for» the invention is haired and

Hg. 8 the aefceaatiactte sectional view of a xerograyhiaoken suitable for continuous "Bd autoeatiechen" operation Maaohine, where the invention is carried out in Terfehren.

The present invention is based on the recognition that, when arranged as described in US Pat. No. 2,836,723, lorotrons appear over a photoconductive surface a voltage is charged which was in equilibrium β Bit dea corotron causes. This lack of equilibrium applies to everyone Arrangement by sizes such as the torotrondurchaieeser, the Kediun and the distance between the corotron and the photoconductive area as well as the potential difference between the two.

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The equilibrium voltage must lie between the potentials. Has a photoconductive surface or part of it facing one another If the equilibrium voltage is lower, the photoconductive surface does not contain the charge given off by the corona device on. This will make the parts of the charged hache that were previously led to a lower voltage, brought to the level of the equilibrium voltage. However, if the equilibrium tension is the same or less than that already on the photoconductive surface below the tension present half of the corotron, then from this surface

no charge taken up, so that it remains electronically unchanged.

This is because the potential difference between the photo-conductive surface and the corotron for accepting charges not sufficient * Ee charges are given off by the corotron, However, these are repelled again by the stronger fields on the photolable surface and directed to the shielding of the corotrons. If there were no shielding, it would. the corona electrode bring the photoconductive surface to the equilibrium β voltage and then no longer give off any charge as long as the potential difference would be less than the value required for an emission.

This tendency of a photoconductive surface, ia the area of a lorotrome, an equilibriumepanaunf aasuiieluien, let an eiaaei tiger Torganf. The delivered corona charge has no Wikrun * on the photoconductive surface parts that have a potential equal to or greater the equilibrium voltage. The parts of the photoconductive However, areas with a lower potential than the equilibrium voltage are charged to the equilibrium voltage, where-

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naph no further liijcung on this surface area is omitted, "da .these are then no longer below the equilibrium voltage. Xa this note, the equilibrium voltage can be seen as a corona * Aurfechalteepannuixg be viewed. It was also found that dal those parts of the photoconductive surface whose tension aa «esten is different from the equilibrium tension first and the fastest to charge.

The way in which this principle is advantageously used for xerography is shown in the figures. In the Pig. 1 to 3, a xerographic image plate 10 is shown, that consists of a conductive base 12 and a coating of a conductive material H thereon, for example Selenium, is formed. The electrostatic images are generated on the layer 14. The photoconductive surface can be in the form of Image plates commonly used for xerography for Creation of latent electrostatic images.

1 schematically shows a cross section of a photoconductive * ( area after development. The plus signs inside) of the photoconductive layer identify non-discharged parts 16 of the exposed photoconductive area which correspond to the image area parts of the copy to be reproduced. The parts of the photoconductive layer 14 without a plus sign identify discharged parts 18 which correspond to the surface parts of the copy to be reproduced which do not belong to the image. The minus signs on the parts of the image surface, surrounded by circles, identify negative toner particles that are on the parts of the image surface due to the electrostatic attraction

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between charges of opposite polarity aind and are distributed imagewise on the photoconductive surface. On the Photoconductive surfaces are also toner particles more positive, more negative and more neutral in the surface parts not belonging to the picture below Arranged polarity. If these particles were transferred to an image base and fixed on it, they would be undesirable Form background deposits.

Up until now, xerography used the lake with background deposits "Transferred image provided on an image sheet and fixed. According to the present invention, however, the developed image is first subjected to background cleaning. This is achieved by moving the corona discharge source 20 relative to the photoconductive surface at a small distance, as shown in FIG. Bas corotron only carries a very low current and has an opposite of the loner of the parts of the image Polarity. In the case shown, this * polarity is positive. During the relative movement between! Corotron and photo-conductive ) Area are those parts of the area that are not influenced by the image, are brought to equilibrium potential by the released corona charge. Sa on these surface parts not belonging to the picture toner particles of different charge and thus positive and negative potentials are present, the »surface parts are charged according to the charge given off together with the toner particles present on them. Regardless of their initial All toner particles that do not belong to the image can be charged to a voltage opposite to that of the surface parts Image area & parts are brought.

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The toner particles present on the image area parts become not influenced by the torona discharge. This is due to the • Koronaunterdrüokunf ". Daxunter understands that the positive . Ladttngsabfafce tea lorotroaa ron the photoconductive surface through the stronger field of equal potentials of the parts of the image surface is repelled. Therefore the corona device has no effect the image area parts and the toner particles present thereon. Its repulsive effect is most pronounced on extended periods

Image surface parts · It is due to the lack of emission lines Shown over the extended part of the image area in FIG. In '

Corona suppression appears in smaller parts of the image area than a turning of the Xorona emission around the positively charged image area, whereby it reaches the neighboring areas of the image that do not belong to the image. Dite is represented by the bent lines on the small image area part and on the sides of the expanded image area part in FIG. 2. This turning of the corona emission, including small parts of the image area, is often referred to as the "island effect". In both cases, namely the repulsion of the corona emulsion by extensive image area parts J or the _{bending around smaller image area parts r} , the result of the directional concentration of the charge in the image area part as well as the toner present thereon occurs.

Might assume that the presence of toner is one of the first Polarity on the picture surface parts the charge of these picture surface parts of opposite polarity is neutralized and therewith the we Corona discharge8 (iuelle worsened. This consists but not a problem. Ss is emphatically demonstrable that in the

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Practice the charge of the Tonera generally less than $ 20 of the charge the photoconductive area in the image area parts. Therefore so the greater part of the charge is effective in the image area parts even after development. So it's in these parts there is still enough charge left to cope with the invention to achieve corona suppression.

The polarity. : the toner particles after exposure to corona emission is in Pig. 2 shown. It results from a Ver-P 'Same as Fig. 1. This background cleaning step is normally carried out in the dark, in accordance with usual Fraxis, so that the charge of the image area parts of the photoconductive Surface is not affected by incident light.

After the toner particles of the image surface parts and the surface parts not belonging to the image have obtained opposite polarities due to the corona emission, the toner particles of the image surface!

> wear and be fixed on this. Using a positive Transfer corotrona 22, shown in Fig. 3, facilitates this Transfer of only parts of the image to the surface. The toner particles of the surface parts not belonging to the 3Ld, the one have opposite polarity to the transferred toner particles » are through your with the transmission torotron over one end of the day Polarity of the sound on the picture substrate repelled.

This embodiment of the invention was made in view of the

written on elm lildblatt, dl «

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however, it can also be used on any other surface , for example on tissue paper and so on, as well as on an intermediate image carrier for the production of printing plates.

The application described the positive Bildfächenladung, Ais poeitiven Reinigungskor * otrons and the positive transfer · ¹ · corotron with a negative toner particles is only an exportation ungsbeispiei. As the skilled person for xerographic art understand, the development may be positivein toner and * Fe > negative image surface division or also reverse development, ie background development through the same gate polarity and image polarity, can be carried out together with the present invention through the correct selection of the different polarities Image is used for the dissipation of a negative charge on a bucket of xerography without an image plate, the generation of charge causes the creation of a latent electrostatic image, whereby the negative charges which are not dissipated form the areas of the surface. To create a positive reproductive | In this electrostatic latent image, negatively charged toner is used along with a positive corotron. With regard to this exemplary embodiment, the invention consists in the use of a cleaning corotron with a polarity which is opposite to the polarity of the toner lying on the surface parts to be developed. The polarity of the cleaning corotron does not always have to match the polarity of the surface charge initially borrowed.

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The use of the method according to the invention is not dependent on the development process. This results from the fact that the reversal of the toner polarity is basically a puncture of the charge distribution on the photoconductive surface ± b%. The addition to the choice of the correct _polarity% remaining other element of the system is only in the retention of the charge distribution on the photoconductive surface to the date of au achwachen Reinigungeladung.

w That in the Pig. The second exemplary embodiment of the invention shown in FIGS. 4 to 7 is similar to the exemplary embodiment already described, but differs from this in the image transmission method. The Pig. 4 and 5 are with the Pig. 1 and 2 identical. This means that both exemplary embodiments are identical with regard to the development and the steps prior to cleaning, ie developed image areas with toner particles of different polarities are assumed in the image area parts and the area parts not belonging to the image. According to the second embodiment of the invention, however, an image transfer corotron 26 is used, the polarity of which is opposite to that of the image transfer corotron 22 of the first embodiment. This is shown in FIG. 6. The transfer corotron used here thus has the same polarity as the toner particles on the image surface parts. If an image sheet 28 is brought into contact with the developed photoconductive surface, then by the action of the lorotrone 26 of the gasified non-sub-image toner is removed from the xerographic surface and bound on the transfer sheet 26. As a result, the flower

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Basic surfaces of the xerographic surface are cleaned of toner and for subsequent image transmission in the usual way, as described in Fig. 7 is prepared. How ready in context 3, a conventional image overlay 30 and a transfer skrotron 32 of conventional polarity are used. The toner image, free of deposits from behind finds, can, however, also be left on the xerographic surface, for example for xerographic prints or similar.

This embodiment of the invention is especially for Xero-

suitable for prints where on a conductive surface with

Photoconductive layer a toner image is generated and fixed. This results in a xerodruoc plate. Both exemplary embodiments of the invention are suitable for use on flat image plates. Furthermore, the wide range of instructions is also suitable for continuously and automatically operating xerography machines, but requires the use of a transfer sheet which is necessary for cleaning and which passes through under the flow of a transfer electrode of opposite polarity provided for this purpose i the machine is operated, the image transfer known per se is carried out. This previously required transfer sheet can be designed in the form of an endless belt which is arranged between the cleaning electrode and the usual transfer point. With the first exemplary embodiment of the invention, a single door cleaning prior to the image transfer is not required, which is why this exemplary embodiment is more suitable for continuously and automatically operating xerography machines of the type customary today.

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The transfer paper or background cleaning tape required for pre-cleaning can be any dielectric material or a dielectric-coated conductor. ■ A conductive material that touches the photoconductive surface would dissipate the fields present on the photoconductive layer and thus dissipate the previously existing charge distribution from this surface and the toner. While paper is a useful dielectric for removing non-image toner, it has been found that smooth surfaces such as Mylar or Teflon allow this toner to be removed more completely. A smooth surface is desirable for toner removal because it more completely covers and contacts all surface portions of the photoconductive layer. A toner particle that is not part of the image is not easily transferred to a rough surface if it does not allow full contact. A rough pre-transfer surface is also undesirable in other respects, since it removes the toner deposits from the image surface parts as a result of greater friction. For both reasons, the glowing surface is preferred.

In Fig. S a xerographies before H machine ZV »ν continuous and automatic operation is shown. All procedural points marked by 3 letters are known in the xerographic technology. To understand the application of the present invention in such a machine, the various xerographic process stations ia movement - area of the xerographic surface are described in the following.

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At the charging station A there will be a uniform electrostatic charge on the photoconductive layer of the forex drum upset.

At exposure station B, a light or radiation pattern of the image to be reproduced is projected onto the drum surface, so that their charge is diverted into the exposed parts of the fluid becomes and becomes a latent electrostatic image of what is to be reproduced Image results.

At the development point C, a toner powder is provided xerographic developer with a charge oppositely polarized to that of the electrostatic latent image brought into contact with the drum surface, causing the toner particles adhere to the electrostatic latent image and a xerographic powder image in one of the image to be reproduced generate the appropriate configuration.

The xerographic powder image is like from the drum surface active electro-on an image sheet or other Bildunterla ^ e transferred to the Transfer Agent D.

At the drum cleaning and unloading station E, the drum surface to remove residual toner particles after image transfer brushed off and switched on a relatively bright source of light, providing a practically complete en-Qaaung of any reetlicher causes electrostatic charge.

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As previously described, these are all process stations common in xerographic technology. Between the development station 0 and the image transfer station D is, however, a corotron arrangement provided for background cleaning, which is used to carry out the process according to the invention.

The corotron assembly 34 already works for the figures 1 to 3 and 4 to 7 described manner. The developed image is guided past the cleaning corotron 34. This one too "polarity opposite to the toner particles on the image area parts to have. The corona emission of low amperage then brings ulle toner particles that do not belong to the image widen surface areas

a charge having a polarity opposite to that of the toner particles of the image area parts. The developed image is then guided past the transfer station for transferring only the image parts to an image base, after which further fixing can take place. The image transmission is carried out by means of a conventional transmission corotron 36. The drum is then moved past the cleaning station to remove the untransferred toner particles, one or all of the toner particles that do not belong to the image. The part of the photoconductive surface of the drum treated in this way is now ready _{for further charging, exposure and development within a continuous working cycle f.}

In addition to the cleaning effect of the inven-

Corotrons in accordance with the intended use and the associated avoidance of background deposits in the developed image and

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still the final copy results in / a further advantage. Is the· .' Photovoltaic surface for binding figuratively distributed charges and corresponding amounts of toner are extremely weak, as can occur through prolonged use or when the toner concentration is reduced, the deposition of toner in the image areas becomes very small. If this occurs together with relatively heavy background deposits, it is difficult between image areas and any areas that do not belong to the image on the final copy su lower sheaths. Ah, this has the greatest effect on line drawing

and copies of typefaces. Correspondingly, at- ^ for example the middle part of the letter ο of the letter itself cannot be distinguished, so that this appears as a black point. If there are two letters 1 next to each other, so can a strong background of toner between these two bulges the faint letters themselves cannot be distinguished and both appear as a continuous black area. This mistake is often referred to as "letter or letter deposit". If, however, according to the invention, the cleaning corotron is used, which removes the undesired amounts of toner, very weak deposits are also possible Deposits of toner in the image area parts can be divided into two different groups due to the absence of background deposits. Therefore, by using a cleaning corotron in xerographic machines, the The legibility of the copies is also improved if the toner deposition in the image area parts is comparable to the toner deposition in the background area parts.

The present invention is in a variety of conditions applicable. One of the applicable operational cases arises at

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an initial charge of the photoconductive plate to 800 volts, reducing this voltage in adjacent areas to 600 volts and in unexposed areas to 40_ volts . 06 microamps / cm can be used. This results in approx. 0.7 microamps at a distance of 25 cm. These conditions are only an example of operation, many changes in values are also applicable.

The present invention has been described in terms of its nature and advantages with the aid of specific embodiments. All further embodiments possible in the rhyme of the following claims are embraced by the basic idea of the invention.

Claims

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Claims (1)

Claims 1. Verfäiren for image generation in the form of a non-conductive surface made of charged toner particles powder image, which is transferred to an image carrier , characterized in that the powder. image-bearing non-conductive surface (H) is exposed to a weak corona discharge (20) with a polarity opposite to the polarity of the charge of the toner particles on the image surface parts (16), whereby the toner particles on the surface parts (18) not belonging to the image have a polarity opposite to that of toner particles on the image area parts (16) obtained and the ULeytraaun ^ merely represent toner particles is facilitated in the Bildflächentsilen (16) or the toner parts in the not belonging to the image Fläciienteilen (1S) onto the image carrier (24). 2. The method according to claim 1, characterized in that the powder image by charging a photoconductive Isolieretoffläche (H) with electrostatic J charge, exposure of the charged photoconductive «Isolierstoff- 'surface (H) for the partial discharge of the charge in an image-like manner Distribution and development of the photoconductive insulating surface (H) »it is generated with charged toner particles. 3. YtrfAren naoh claim 2, characterized ge k e η η that furthermore an electrostatic transmission generation of the toner particles from the 3ild surface parts (16) of the BADORJGiNAL ". 009840/1681 • ft. photolei! capable insulating material surface (14) on dexi image wore * (24) carried out v / ird. 4. The method according to claim 2, characterized in that furthermore an electrostatic transmission the toner particles from the planar parts (18) of the photoconductive Ieolieroffläche (U) that do not belong to the image is carried out on the image carrier (24). 5. The method according to claim 4 _f, characterized geke η η, that after the transfer of the toner particles from the surface parts (18) not belonging to the image Arner an electrostatic transfer of the toner particles from the image area parts (16) of the fotoleitfälii ^ en insulating surface (14) a final image carrier (30) is performed. 6. Device for carrying out the method ^ emäfi one of the breakouts 1 ^The 51 »it devices for generating a powder image from charged toner particles on an insulating surface and for transferring the toner particles from the insulating surface to an image carrier, characterized by geke η η that a Arrangement (20) for treating the insulating material pool (14) carrying the powder image is provided with a weak corona discharge with a polarity opposite to that of the formation of the toner particles on the image surface parts (16) of the insulating material surface (H), whereby the toner particles open up the surface parts (18) of the insulating material surface (14) which do not belong to the picture have a polarity opposite to .22- 009S40 / 16 «· BAD ORlGiNAL chain of those of the toner particles on the surface parts (16) is obtained and the selective transfer of only those toner particles present on the surface parts ( 13) that do not belong to the image or only the toner particles present on the image surface parts (16) is facilitated by the insulating surface (14). 7. Slighting according to claim 6, with a charging device zam applying an electrostatic charge to a photoconductive surface, an exposure device, for dissipating the charge in an image-wise distributed pattern of image area parts and non-image area parts corresponding to a reproduced part Image, a developing device; for applying a xerographic developer material to the photoconductive surface and binding a * toner powder in an image-like distribution on the photoconductive surface and a transfer device for transferring the toner adhering to the photoconductive surface to an image carrier, thereby marked that between the development ι device (C) and the IT transmission device (D) an i regulation (34) on treatment of the developed photoconductive Area (10) has a weak corona charge with a polarity opposite to that of the charge on the toner particles on the image areas len of the photoconductive surface (10) is provided, whereby the toner spots on the do not form an image belonging surface parts of the photoconductive surface (10) has a polarity opposite to that of the toner particles on the Image area parts received and the selective transfer only odeyhur on the area parts that do not belong to the image BADORiGINAL 009840/1666 -23- the toner present on the image area parts from the photoconductive surface (10) is facilitated (Pig. 8). 8. Device according to claim 7, characterized in that g e k e η η '-drawn that further an image transfer device (36J for facilitating the electrostatic transfer of the toner particles from the image area parts of the photoconductive Surface (10) is provided on an image carrier. 9. Device according to claim 7, * characterized in that · g £ k e η η draws that further a device (26) to facilitate electrostatic overtraining of the toner particles from the not zuiu Ej Id belong to the surface parts the fe toleitfiihigen surface (14) on an image carrier (2c) is provided. 10. The device according to claim 91 characterized geke η η that further an ISi
device (32) for facilitating the electrostatic transfer of the toner particles from the image surface portions of the photoconductive surface (H) after the removal of the toner particles from the surface portions not belonging to the image onto a final image carrier (30). -24- 009840/1666 Blank page