DE2009346A1 - Electrophotographic recording material - Google Patents

Description

P A T E N T A N WÄ LT E gOOSSAS 8 MUNICH 22

DR.-ING. WOLFF, H.BARTELS, "'' thierschstrasse β

DR BRANDES _{7 DR 1} -ING HERO

R / th

Reg. No. 122 249

EASTMAH KOMK COMPANY, 343 State Street, Rochester, Few York State, United States of America

Electrophotographic recording material

The invention relates to an electrophotographic recording material, consisting of a layer support having an electrically conductive layer, at least one on top applied photoconductive layer, as well as optionally intermediate and / or Beeksehicaten.

Sur conducting elektrophot © photographic processes, for example the so-called xerographiechen process is known to use a elektrephotograpMeches recording material on the Eegel from; a layer support, an electrically conductive layer applied to it and at least one photoconductive layer applied to Ser electrically conductive layer. Di® photoconductive layer iron normal white electrically insulating material,

«Lektriscfeör resistance changes with exposure, ι · Β. at Mläsäiigt? Exposure as a function of the amount of radiation. The shift! Cabu Aue the door rs £ 3hi the "t" n _f usual known material

fen exist. Ale are suitable, for example, from layer supports Paper and film-forming polymer resins, e.g. polyethylene terephthalate or cellulose acetate. The electrically conductive layer can be in various forms, e.g. in the form of a separate layer, part of the substrate or in the form of the substrate itself. They are electrical conductive layers of various types known, e.g .:

a) containing metal layers, e.g. made of aluminum and Laminates made up of paper layers,

) b) Metal plates, e.g. those made of aluminum, copper, zinc and brass,

c) metal foils, e.g. those made of aluminum and zinc,

d) vapor-deposited metal layers, e.g. those made of silver, aluminum and nickel,

e) layers made of resins, e.g. polyethylene terephthalate, disperse semiconductors, e.g., of the type described in U.S. Patent 3,245,833, and

f) Layers of electrically conductive salts such as those in U.S. Patents 3,007,801 and 3,267,807 type described.

With the alatetrlaoh conductive marked with d, e and f Such layers are, if necessary, transparent layers that are used for the production of transparent electrophotographisohtn Aufseiehtrungematerimlieis, »which e.g. Back instead of vojs, the front exposed or see below Slides that can be processed are usable.

To carry out an optical photographic process of the specified type is used in such electrophotographic a Recording material is usually used in the dark correspondingly long dark adaptation, with an even surface charge vereeheau Das charged elektrophotographieche Recording material is then an activating

0 0 9 8 3 7/1963 _ßAD

Radiation pattern exposed, which has the consequence that the surface potential image-wise different depending on the light energy incident through the radiation pattern is greatly reduced. Bas this way in electrophotography Recording material generated latent electrostatic charges corresponding to the different surface charges Image is then known with the help of a usual made visible by electroscopic marking agent. Am such marking agent or toner agent either incorporated into or on an insulating liquid dry carrier material can be applied, can on the exposed surface of the electrophotographic recording material deposited either on the charged districts or on the uncharged districts. The deposited Marking agent can then either be applied to the surface of the developed electrophotographic recording material by conventionally known methods such as by Exposure to heat, bridge or *. ^ 3 solvent vapors, permanent fixed or transferred to an image receiving material and be fixed on this. If necessary, this can also be The electrostatic latent image obtained upon exposure is transferred to and developed on an image receiving material will.

In the electrophotographic recording materials of the specified! type, the electrically conductive layer has the task of forming a highly conductive reference plane, whose In the ideal case, the potential corresponds almost or practically completely to the earth potential. The known electrically conductive However, if they are not grounded, layers tend to disadvantageously during the charging of the photo-conductive Layers with the help of a corona discharge in relation to build up a potential on ErdpotsHtial. So amounts e.g. the potential of an ungrounded photoconductive Layer of the specified type d, e or f usually around 4-50 or more volts if the surface of the photoconductive Layer is charged to 600 volts. You charge

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different between the electrically conductive layer and the surface of the photoconductive layer is therefore a maximum of 150 volts. So it becomes one with surface charge provided electrophotographic recording material exposed to an imagewise pattern of actinic radiation, the photoconductive layer in the areas hit by the light electrically conductive and that The surface potential of these areas is reduced to a value which is approximately that of the electrically conductive layer is equivalent to. Due to the small potential difference between those struck by light and those not struck by light Districts, the latent image generated is therefore often only an inferior quality visible image or at all not developable.

Correspondingly unsatisfactory results are also obtained with the aid of known electrophotographic recording materials, the electrically conductive layers of which are not sufficiently grounded. For example, the known Erdungsmethockwi, for example by means of metal strips "rollers and the like, with the substrate" jfder au grounding elektrophötographischen Aui ^ elchnungsmaterlalien be electrically brought .Ό conductive contact in only a limited effect. Little success further iet an attempt to cause the ground by producing a direct electrical contact between the electrically conductive layer and wet, since this measure Aehr difficult to carry out and r due east & fact that the eu grounding electrically conductive layer is extremely thin, for example, a starch of only 0.025 ram or less, is not very effective and is also problematic with regard to the stability of the electrical recording material to be grounded, especially if it is to be moved during charging. In the case of the known electrophotographic recording materials, "while the photoconductive layers are being charged, the electrically conductive layers practically to earth potential."

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to keep the surface charge as high as possible on these catfish to apply to the photoconductive layers and in to get this.

The object of the invention is to provide an improved electrophotographic Specify recording material whose electrically conductive layer is grounded in such a way that the photoconductive Layer can be charged even when moving the recording material.

The invention is based on the surprising finding that the stated object can be achieved in that the electrically conductive layer with the help of a type of lacquer layer or a Lacquer coating of precisely defined composition "grounded", i.e. more precisely electrically with a device that specifies a potential is conductively connected.

The object of the invention proceeds from an electrophotographic Recording material consisting of a layer support having an electrically conductive layer, at least one photoconductive layer applied thereon and optionally Intermediate and / or top layers, and is therefore ger ' indicates that there is a laek layer (or varnish coating) a resinous film-forming polymeric binder and an electrically conductive material dispersed therein-j which the electrically conductive layer with a fofcential prescribing device electrically conductively connects.

Xm electrophotographic recording material according to the invention The lacquer layer, which can also be drawn as a kind of lacquer application, is used to produce an electrical one Connection between the electrically conductive

and a device specifying © in potential or ~ Per'.AtM <£ ruek "Ma * ee. ^w is a relative term,

- 5a - ..-..... 000137/1913

"- ^ij: -" O am ORlGlNALlNSPEGiTED

with one relative potential, with the other positive or negative potentials are referred to. So z. B, the indication "+ 600 volts" 600 volts above the reference value used basic potential. For the sake of simplicity, the basic potential is arbitrarily given a value in the following

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associated with zero volts.

The electrically conductive lacquer used to produce the lacquer layer has advantageous adhesive properties which lead to the formation of a firm bond between the lacquer layer and the material coated therewith, for example an insulating layer or an electrically conductive layer carrier. The varnish used is also distinguished by the fact that it is inert to aliphatic solvents. If, for example, it proves to be expedient to clean the electrophotographic recording material according to the invention with solvents of the specified type, the varnish layer is not adversely affected. Even aliphatic fluids of the type used in liquid xerographic developers do not affect the laek layer. The inventively used electrically conductive Laekschicht further has the advantage that it is wear-resistant "If, for example grounding the electrically l © itf ^F * Scfeicht strength. i © @ © bar © = -. photographic recording material © naeB. In the example given below, if a metal strip or a metal brush works, the parts of the lacquer layer that are in contact with the metal, e.g. those at the edges of the electrophotographic Laekschichtteile arranged on the recording material, not rubbed off when the el @ kt; röptetögp? See recording material is moved. Since the lacquer has only a low specific surface resistance per unit area, the electrically conductive® layer is effectively at earth potential during charging held, regardless of whether the electrophotographic recording material according to the invention is left in a fixed place or moved.

The measurable on an insulating surface electrically © power loss ^w with "specific Oberflächenwiderstanä usually referred to. In this case the term is, however, in terms of the resistance of the crowd control

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capable media forming electrically conductive layers, which are evidently called the electrical current through the Electrophotographic recording material carrying electrical conductors act, used. For determining the conductivity properties The specific electrical resistance of conductors and semiconductors is usually measured. Acts However, if such conductors are thin, electrically conductive layers, the electrical conductivity can be determined Determine by measuring the specific surface resistance, which can be measured directly and one for practice represents useful value.

In order to avoid confusion, it should be emphasized that the units of measurement for the specific electrical resistance (ohm-cm) and for the specific surface resistance (ohm per area) are different from one another. So calculates "I 2, B. For an electrically conductive material in the form of a layer or a film with ohmic electrical behavior, the electrical resistance per surface from the specific electrical resistance divided by the layer thickness, but the value calculated in this way for the resistance does not correspond to the actual value in all cases Geiaessexien specific surface resistance. To determine the surface resistance (ohms per area), a square test specimen cut out of the ku test layer with sides of 1 cm is provided on the opposite sides with 1 ca alkaline electrodes made of stainless steel, whereupon the resistance measurement is carried out using a so-called ^W RCA -Senior Volt Oh © yst * done. The specific resistance of the lacquer layer present in the electrophotographic recording material according to the invention is as a rule less than 10 ohms per area.

You in the electrophotographic recording material after Invention present lacquer layer can be the most varied of customary known, in the form of electrically conductive material of finely divided particles contain substances with good electrical conductivity. Typical suitable der-

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like electrically conductive substances are, for example, carbon black, graphite, nickel, silver and the like, which are particulate substances with good electrical conductivity. The rope size of these electrically conductive materials can be very different, but is usually about 0.001 / a to 10 yu. The optimum particle size can easily be determined by the Pachmann using customary known methods.

The lacquer layer present in the electrophotographic recording material according to the invention can contain, as polymeric binder, a wide variety of customary known resins, provided that they are soluble in known, customarily used solvents that are not unsubstituted aliphatic solvents and when coating substrates are formed are capable of pilms or layers. Typical suitable such resins are eg * Styrene-buta & Äenmischpolymerisste, silicone resins, styrene-alkyd resins, silicone ·? Alkyd _f soya alkyd resins, polyvinyl chloride, polyvinylidene chloride, Yinylldenchlorld-Acrylonitrilmlschpolyaerieate, polyvinyl acetate, vinyl acetate VinylchlQridmischpolymerisate, Polyvlny acetate! Such as polyvinyl butyral, polyacrylic UBD - »ethacryleeter ₉ eg * poly (methyl methacrylate, poly (α-ethyl methacrylate) and poly (isobutyl methacrylate), polystyrene, nitrated polystyrene, polystyrene styrene, polyester, sB poly ethylene terephthalate, phenol formaldehyde resins, poly (ethylene glycolate, polyether glycolate) Bishydroxyätlioxyphejiylpropaiiterephthalat), Oopolymer® from Tinylhalogenarylaten and Tinylaöetat, eg, Poly (Tinyl «m-Bröaob« neoat-Co «¥ inylacetat), Polyolefins, eg, Polyäthylen, föXypropylen uad dergleiohea.,

? learn "n sur!" retelling from Emrsen of the specified type known, So lcann s.B. the production of styrene

riÄCh the place in the US Patents 2,361,019 Z methods described 258,423, present to produce the r * in Ü »n elektrophotographiechen Amfsseiclmungamaterisaeh ä BrfiMune suitable Lfioksehichtan

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Resins are also commercially available, for example under the trade name "Vitel PE-1O1 ^W," Cymac ¹ ×, "Saran £ -220", "Lexan 105" ^s and "Lexan H5. To be particularly advantageous in terms of adhesion properties has one himself Proven from a copolyester existing polymeric binder, which is obtained by reacting dimethyl terephthalate with a mixture of 2-m-butyl-2-ethylpropane-1,3-diol and ethylene glycol present in a molar ratio of 50:50, with 2.5 mol percent of the Dimethyl terephthalates can be replaced by pyromellitic dianhydride.

For the production of coating materials of the specified type the electrically conductive materials and polymeric binders used become a solvent for the binder mixed. Typical suitable solvents are, for example, organic solvents, for example aromatic solvents, such as benzene, xylene and toluene, also ketones, e.g. acetone and 2-butanone, halogenated aliphatic hydrocarbons, e.g. 1,1,1-trichloroethane, methylene chloride and Ethylene chloride, ethers, e.g. tetrahydrofuran and diethyl ether, as well as mixtures of such solvents. The coating compositions obtained in this way can be used in an advantageous manner are applied to the edges of the electrophotographic recording materials in such a way that the obtained Lacquer layers with the electrically conductive layers Ρ of the recording materials are in contact and, after drying, they are in contact with a ground effecting mass can be brought.

The electrically conductive substances or pigments can be present in various concentrations in the charging materials which can be used to produce the Laekeobiohten. It has proven to be weekly to use them in concentrations of about 0.1 to 100 parts by weight, preferably from 0.5 to 7.5 parts by weight, per part by weight of polymeric binder. As a rule, the coating measures used consist of at least 0.1 £, preferably at least 1 Ji, based on the coating measures, ava solids

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- 2D09346

electrically conductive materials and binders. It has proven to be particularly advantageous to use coating compounds which, in the form of a dispersion in a polymeric binder, contain a mixture of graphite and an electrically conductive carbon black in the specified weight ratios, e.g. one known under the name ^w Dixon Graphite No. 635 *, as Lubricants defined graphite and the electrically conductive oils known under the name "Vulcan XO72 ^H " fenruß. The weight ratio of graphite to electrically conductive carbon black is advantageously 0.5 to 2.0 parts by weight of graphite per part by weight of carbon black.

The coating oils obtained in the manner indicated can be applied to the edges of the electrophotographic recording materials by customary known methods, for example with the aid of a brush or by spraying can be very different, but is usually about 0.025 to 0.25 mm. The Iiaekseliichten obtained are then dried, either at room temperature or at slightly / elevated temperatures from e.g. For example, about 20 "to 50 ⁰ C. Sin particular advantage of the erlbsltenen in this way Laekschichten is the fact that the coating compositions shown below their preparation used to einem.gewissen to teaäe in the electrophotographic Aufzeichmungsmaterialien el & ctringen, so that an extraordinarily good electrical contact with the electrically conductive layers is achieved.

As already mentioned, the electrophotographic recording materials according to the invention generally have several Layers on. So s.B. the substrate that is usually a transparent substrate made of electrically insulating materials, an electrically conductive layer on. This electrically conductive layer can either be on the The layer base can be applied or vapor-deposited thereon in the usual known manner, or it can be electrically applied by impregnating the layer base with the one used for its production conductive mass this be incorporated. Therefore, in advance

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20093A6 - 4-r -

lying trap of a "layer support", an "electrical conductive layer "or a" substrate provided with an electrically conductive layer ", so these designations include all options listed, that is, both the case where the layer support with the electrically conductive mass coated «soaked with this or vaporized with this. With the layers used and electrically conductive layers can be of the specified type.

The electrically conductive layer of the electrophotographic recording material according to the invention is at least a photoconductive layer composed of an organic photoconductor and a polymeric binder for the photoconductor Mistake. The photoconductive layer can optionally be used to change the spectral sensitivity or the electrophoto-sensitivity of the electrophotographic recording material contain a sensitizer for the photoconductor. For the production of the electrophotographic recording materials according to the invention, a wide variety of customary known organic photoconductors can be used. Typical suitable such photoconductors are e.g.

German patent specification (patent application P 19 54 500.7)

described.

A wide variety of customary known compounds are suitable as sensitizers for the photoconductors present in the photoconductive layers, for example pyryllum dyes, β.B. Thiapyry ium- and Selenapyryliumfarbeteffsalze of the type described in US Patent 3,250,615, further fluorenes, r, .B * 7 »l2-dioxo-13-dibeni;! Ö {" _s h) fluorene, 5,10- Dioxo-4a _y 11-diajtabeni5o (b) fluorene and 5 »15-dio-7-oxadiben» o (b, g) fluorene, aromatic nitro compounds of the type described in US Pat. No. 2,610,120, anthrones, sB those of the in U.S. Patent 2,670,284, quinones of the type described in U.S. Patent 2,670,286, benzophenones of the U.S. Patent

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Al

Type described 2,670,287, Miiazole of $ YPS described in US Patent 2,732,501, further mineral acids, carboxylic acids, for example maleic acid, Diehloressigsäure and salicylic acid, SuIfon- and phosphoric acids, as well as various dyes such as cyanine dyes such as carbocyanine e, merocyanine , Diarylmethane, thiazine, azine, oxazine, xanthene, phthalein, acridine, azo and anthraquinone dyes and mixtures thereof. The use of pyryliuin, selenapyryliura and shiapyryllum salts and of cyanine dyes, for example carbocyanine dyes, has proven to be particularly advantageous.

■ ■. ■ ■. ■■ - ■ .- I

Used for the production of the building masses from one organic photoconductor and a binder for the photoconductor a sensitizer is used, so it has been found to be sweckiform proved to mix the sensitizer with the coating composition so thoroughly that the sensitizer in the photoconductive coating mass® obtained photoconductive Layer is evenly distributed. JSt if applicable can be the sensitizer of the photoconductive coating compound can also be incorporated by other customary known methods. The photoconductive layers of the electrophotographic Recording materials according to the invention

however, as already mentioned, do not contain a sensitizer for the _{development of their Λ.} 33a je- I ü.ooh dtr the use of sensitizers themselves. In comparatively g®ri »g®E KmmentTien & n a noticeable improvement in the safety of such photoconductive layers, the use of sensitizers as b @ ^ @ nd @ rs has been very urgent. ητ1β tn. The for Eapfindlichkeitsigeigeruiig the

Layers required «Concentration & n can « tary reconcile at least the optimal®

ron depends various factors from "@ t @ Ieittrs and Seneibilieato

»Trlcliofe« Bapfindlehkeitsteigermig is in ü> m? Hegel Nugats «Imta geeigaiettn Stneifeilieators in losseatratio ΨΦΜ- about 0.0001 to 30 ffewiohteproeent-, based on äae öa-

00S837 / 1063

weight of the film-forming coating composition caused. In the As a rule, the sensitizer of the coating compound to be sensitized is used in concentrations of about 0.005 to 5 »0 percent by weight, based on the total weight of the coating compound, added.

For the production of the photoconductive coating compositions are The most varied, customary, known solvents can be used for the components present in the Besohiohtungsmasaen. Typical suitable organic solvents are e.g. benzene, toluene, acetone, 2-butanone, chlorinated hydrocarbons, for example methylene chloride and ethylene chloride, furthermore Ether, for example tetrahydrofuran, or mixtures of such solvents.

In the coating compositions which can be used to produce the photoconductive layers, the photoconductive compounds are expediently present in concentrations of at least about 1 percent by weight, based on the coating composition. The upper limit of the consumption range for photoconductors can be very different. In general, it has proved advantageous, the photoconductive compound in concentrations of about 1 to 99 weight percent, preferably from about 10 to 60 weight percent of ₉ sohichtungsmaese on the Cmd to use "

In the electrophotographic recordings according to the invention, the photoconductive layers present can be of different thicknesses. As a rule, the photo-old algae layers have proven to be EweckaSig in a thickness measured in the wet state ύοώ. © tv "0.025 to 0.25, preferably from about 05 O ₅ am to apply 0.15 _f. The thickness of the photoconductive layers, however, as already mentioned, depends on the intended use and can be more expensive than electrophotographic.

the electrically conductive XaoV; not showing electio-009837/196 3

As already mentioned, photographic recording material according to the invention can be used in an advantageous manner for carrying out the so-called xerographic process. To carry out this process, the electrophotographic recording material is provided with an initial electrostatic charge in the dark by subjecting it to an atmospheric discharge to form a uniform surface charge on the photoconductive layer. During this charging process, the electrically conductive layer of the recording material is kept at ground potential in such a way that the edges of the electrophotographic recording material having the cover layer are electrically connected to Hasse. If this grounding is not effected, the potential difference between the photoconductive layer and the electrically conductive layer will not be large enough to produce a high quality visible image from the latent image formed upon exposure. Bie applied charge remains at & er Ö ^T "lack © the photoleltfitelges layer due to the highly insulating properties of this layer in the dark, that is due to the low conductivity of this layer in the dark condition. Charging can © rfalgen while the to be charged elefetrophotographische recording material at a certain Plats "or while it is being moved. The erfindungsgemäS% n eraieleaden advantages are particularly evident when AEAS srnfzuladende elektrophotographisohe recording material is moved during recharging, since due to the presence in elektrophotographisehen recording material according to the invention, causing the ground! Topcoat the PotentiaMer electrically le it enabled layer as effective on eisiem the potential corresponding to the ground potential is held as if the recording material to be charged is charged at rest. As already mentioned, this fact is due to the fact that the protection of the specified type leads to particularly good contact between the electrically conductive layer and the grounding mass, even when the electrophotographic recording material to be charged is moved.

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The electrostatic charge applied to the surface of the photoconductive layer is then in the manner of the surface of the layer selectively removed that the electrophotographic recording material in the usual known Way is exposed imagewise, e.g. with the help of a contact printing technique, by lens projection of an image or with Using reflex or bireflex methods, so that a latent electrostatic image is generated on the photoconductive layer. This is the electrostatic forming the latent image Charge pattern is generated upon exposure of the film surface due to the fact that the light energy incident on the photoconductor dissipates that in the exposed P areas existing electrostatic surface charge depending on the radiation intensity impinging in these areas.

The charge pattern produced during the exposure is then developed or transferred to an image receiving material and applied developed this. During development, either the charged or the uncharged areas of the charge pattern are passed through Treatment of the exposed recording material with an electrostatically attractable developer comprising optically dense particles made visible. The electrostatically attractable developer particles can be in the form of a dust or a powder and usually consist of a pigment called a toner in a resin-like carrier. For developing full areas, it has proven particularly advantageous to apply the toner to the latent electrostatic image to be developed with the aid of a magnetic brush to apply. Methods of making and using magnetic brush toner applicators are disclosed, for example, in US Pat U.S. Patents 2,786,439, 2,786,440, 2,786,441, 2,811,465, 2,874,063, 2,984,163, 3,040,704, 3,117,884 and U.S. Reissue Patent 25,779.

The latent electrostatic image can also be developed with the aid of liquid developers. To the

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The developer particles are used to carry out the liquid development with the aid of a carrier consisting of an electrically insulating liquid by means of which the latent image load-bearing film surface applied. Development process of the specified type are known and are in numerous references for example in U.S. Patent 2,297,691 and Australian Patent 212,315.

A powdery developer containing developer particles is usually used to carry out dry development used, one component of which consists of a low melting point Resin is made. If the image obtained with the help of such a developer is heated, the resin on the melts Image surface and partially penetrates it, so that the developer powder firmly and permanently on the surface of the photoconductive layer adheres. You're generating a visible one Image can also take place in the catfish that the charge image or that on the photoconductive layer in the specified A developer powder image formed in a manner is transferred and applied to an image receiving material such as a paper base this is developed into a visible, permanent image by melting the resin present in the developer powder will. Development processes of the type indicated are known and are described in numerous references, e.g. in U.S. Patents 2,297,691 and 2,551,582, and "ROA Review", Volume 15.

During development, it is often necessary to use the electrically conductive material in order to achieve a clear image background Layer to keep what at a certain potential in a particularly advantageous manner with the aid of the specified Electrophotographic recording material containing lAokscMcht » can be effected according to the invention.

To illustrate the electrophotographic recording equipment The attached drawing serves naoh the invention. tion in which to represent

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- Mf -

Figures 1 to 5 electrophotographic recording materials according to the invention in the scheme according to advantageous Embodiments,

FIG. 6 shows the electrical circuit customary in known electrophotographic recording materials in the scheme and

FIG. 7 shows the current circuit in the electrophotographic recording material according to the invention in the scheme.

That in fig. 1 shown electrophotographic recording material according to the invention consists of a layer support 12, an electrically conductive layer 11 applied thereon and a photoconductive layer 10 applied to the electrically conductive layer, which as a rule comprises a photoconductor, a polymeric binder for the photoconductor and optionally has an optical sensitizer for the photoconductor. At one edge of the recording material an electrically conductive lacquer layer 13 is applied, which dispersed one in a resinous polymeric binder contains electrically conductive material, e.g. graphite. The lacquer layer 13 is connected in an electrically conductive manner to the ground 14 ». The electrically conductive layer 11 and the lacquer layer 13 are arranged so that the electrically conductive layer 11 during charging over the lacquer layer 13 and the Ground H is maintained at ground potential, so that after charging is complete, the surface of the photoconductive layer has a uniform surface charge and the electrically conductive layer is at ground potential and in this way there is a comparatively high potential difference between the two layers.

The in Flg. The electrophotographic recording material according to the invention shown in Fig. 2 differs from that In Fig. 1 shown recording material insofar as the carrier layer and the electrically conductive Sohicht under Formation of an electrically conductive layer carrier 21 are combined. The support of the specified type is e.g. duroh impregnation of a sole carrier with an electric

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conductive salt or by using a sheet carrier obtained from an electrically conductive material. You photoconductive Layer 20, the electrically conductive paint layer 22 and the grounding 23 correspond to those in Pig. 1 arrangements shown.

That in Pig. The electrophotographic recording material shown in FIG according to the invention differs from that in Pig. 1 shown recording material insofar as the photoconductive layer 30 arranged offset from the edge and consequently is not in contact with the electrically conductive paint sheet 33. The substrate 32, the electrically conductive Layer 31 and grounding 34- correspond to those in Pig. I. illustrated arrangements.

That in Pig. 4 illustrated electrophotographic recording material according to the invention differs from that in Pig. 1 illustrated record ... «. Material insofar as the grounding consists of a metal plate 44. The electrically conductive lacquer layer 43 is located both with the electrically conductive layer 41 and with the grounding plate 44 in contact. The grounding plate can be made of known materials commonly used for this purpose, but it does exist preferably made of stainless steel. The support 42 and the photoconductive layer 40 correspond to those in Pig. illustrated arrangements.

The electrophotographic recording material shown in FIG according to the invention differs from the recording material shown in Fig. 1 in that to improve the adhesion between the photolelts Layer 50 and the electrically conductive layer 51 an adhesive layer 55 is arranged. The adhesive layer 55 consists of usual known fabrics with good properties that however, the electrical properties of the photoconductive Do not adversely affect layer 50 or the electrically conductive layer 51. The substrate 52, which is electrically

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£ 0

conductive lacquer layer 53 and grounding 54 correspond to those in Pig. 1 arrangements shown.

9 in Pig. 6 in the schematic circuit is usually in conventional known electrophotographic recording materials similar to the one in Pig. 1 correspond to the recording material shown, but do not have any electrically conductive lacquer layer 13. The photoconductive layer corresponding to the capacitor C _1, the carrier layer corresponds to the capacitor C "and the electrically conductive layer corresponds to the two capacitors common capacitor plate. The earthing is in electrical contact with the capacitor C »· The resistance of the substrate is denoted by R. The resistance of the substrate usually depends on the type of material used to manufacture it. For example, a clear one made of electrically insulating materials, such as polyethylene terephthalate

12 substrate has a linear resistance of over 10 ohms, whereas a paper substrate has a linear resistance of less than 10 ohms. The capacitance of the photoconductive layer (C ₁ ) and of _{the substrate (C 2} ) can also be very different and depends on the thickness of the layers and on the free electricity constants of the materials used for their production. As a rule, the photoconductive layer has a thickness of about 10 microns and the carrier layer, which consists of an electrically insulating material, has a thickness of about 127 microns, which means that the capacitor C ₁ usually has a greater capacitance than the capacitors C ₂ - If a voltage is applied to the electrophotographic recording material between V _Q and 7, the voltage drop across the two capacitors connected in series is inversely proportional to the capacitance of the capacitors. If, for example, a voltage of 600 Veit is applied, the voltage drop in capacitor C ₁ is usually 150 volts and in capacitor C ₂ 450 volts. There is therefore a voltage difference of only 150 volts between the conductive layer and the electrically conductive layer, which leads to the formation of a

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Exposure produced high quality image is insufficient.

The one in Pig. The circuit shown in the diagram 7 lies in an electrophotographic recording material according to the invention containing the specified lacquer layer, for example of the type shown in FIG. 1. The photoconductive layer corresponds to the capacitor O ^, the substrate corresponds to the capacitor O ₂ and the electrically conductive layer corresponds to the capacitor plate common to both capacitors. The resistance of the substrate is denoted by R. Both E and Cg are short-circuited with the help of a line that connects Y .. directly to ground V. The specified line corresponds to the electrically conductive paint layer and acts in the specified manner. When comparing Pigures 6 and 7, it can be seen that the two circuits differ only in the specified short-circuit line corresponding to the electrically conductive paint layer. _{If a voltage is applied between V 0} and V in an electrophotographic recording material according to the invention, the entire voltage drop occurs along the capacitor G ^, since Og and E are short-circuited. For example, if the applied voltage is 600 YoIt, the voltage drop in the capacitor is O ^ 600 YoIt. The resulting voltage difference of 600% between the photoconductive layer and the electrically conductive sole is sufficient to generate a good quality latent image. In contrast, as already mentioned, the

In known electrophotographic

«Tiefejaungaaateri & lien is much lower and, depending on Capacity and resistance of the substrate and the photoi $ itf $ hlg <m Soli not only about 150 YoIt at best,

Me #l «ktr & ph # tographic listing materials according to the Load can be used in a wide variety of common known i'lriäkturABoräauagta exhibit. So they kSnaea e.g. a · or "* Hr * r · $ hrtaltitf £ 3 & igt layers" ntüslten, dit on dpftken

009837/1983

or transparent, electrically conductive layers are upset. Furthermore, the layers present can either be arranged adjacent to one another or separated from one another by barrier layers, for example those made of insulating materials or photoconductive materials of other types, or they can be overcoated with such layers or they can have such layers between the photoconductive one Layer or the sensitizing layer and the electrically conductive layer. Arrangements other than in The type illustrated in the examples and figures have proven to be appropriate and for certain purposes as * Proven to be particularly beneficial. However, all of these arrangements have in common the inventive feature that between the the ground effecting ground and the electrically conductive layer via an electrically conductive lacquer layer of the specified type an electrical connection is made.

The following examples are intended to explain the invention in more detail. Example I.

1.4 g of poly (4 »4'-isopropylidenebisphenoxyethyloo-ethylene terephthalate) consisting of a binder, the 0.5 g of 4.4 ^t -ben« ylidin-bis (N, N-diethyl-m-toluidine) consisting " Photoconductor and 0.04 g of am »2,4- (4-ithpxyphenyl) -6- (4-n amlyoxystyryl) pyrylium fluoroborate, dissolved in 15.6 g of methylene chloride at room temperature with stirring for 1 hour. The resulting solution was applied by hand to a cellulose acetate film substrate provided with an electrically conductive layer consisting of the compound of a carboxy ester laotone of the type described in US Pat. No. 3,120,028, in such a way that the layer obtained was in when wet had a thickness of about 0.1 ma. The coating was conducted at a Blooktemperatur of about 32 ⁰ C. Hach drying, to "edge ine · dt obtained electrophotographic Aufeeichnungsnaterials" int Beschiohtungsmasse the following composition:

009837/1963

Graphite (known under the curve

"Dixon No. 635") 10 g

Binder of the type 2g described in Example 4 "

surfactant (known as

the designation "Amine C ¹ O. 2 g

Methylene chloride 178 g

Applied in such a way that the thickness of the lacquer layer obtained when wet was about 0.127 mm. For the production the specified coating compound were the individual Components in a ball mill for 16 hours using made of stainless steel, 3 »175 mm balls mixed. The resulting varnish layer was for 1 hour at room temperature dried.

The obtained electrophotographic recording material According to the invention, charging was carried out under a positive gorona charge until it was possible to use an electrometer test measured surface potential was about 600 YoIt. The charging was done in such a way that the corona discharge over the surface of the charged, on a solid Platz '. Left recording material was performed. During the charging, the electrically conductive layer became Via the conductive line forming an electrical line to ground Paint layer kept at ground potential '. A copper strip was used as grounding, which is connected to the lacquer layer was in electrical contact.

The charged photoi @ itable layer was then with a a pattern of opaque and translucent areas having transparent film and then for 12 seconds the radiation of an incandescent lamp exposed with a lighting intensity of about 75 m candles. Sas latent electrostatic generated upon exposure Image was then developed in the usual known Weis®, by creating a semicircle of negatively charged over the Pilaeberflache thermoplastic toner particles and G-lasktigelohen

0 0 9 8 3 7/1963

ZH

was poured. It was a good reproduction of the original pattern obtain.

In a comparative experiment, the indicated method was carried out using a known electrophotographic Recording ma-fcerials that do not have an electrically conductive paint layer exhibited repeatedly. The obtained reproduction of the original sample showed, compared to that obtained with the aid of the electrophotographic recording material obtained according to the invention, a lower contrast and a poor image quality in all respects, which is obviously due to the less effective charging

Example II

The procedure described in Example I was repeated except that the electrophotographic to be charged Recording material while charging at a speed Tone 9 m / min, while the corona discharge device is stationary in a fixed place found. A good reproduction of the original pattern was obtained.

In a comparative experiment, the specified procedure repeated except that a known elektrophotographieches Recording material which had no electrically conductive lacquer layer was used. It wasn't Image received.

Example III

The procedure described in Example I was repeated with the exception that the electrophotographic to be charged Recording material during charging at a speed of about 9 m / min, moving and the Oorona discharge device was kept quiet, and that a metal roller, which is in electrical contact with the

009837/1963 _BAD ORIGINAL

Leak layer was found _{f was} used. A good reproduction of the original pattern was obtained

Example IY

This example shows the production of a connector for forming an electrically conductive connector in a particularly advantageous manner Way usable beach sealing compound made from a dispersion of a mixture of graphite and an electrically conductive one Carbon black in a resinous polymeric binder.

10 g of the graphite known under the name "Dixon No. 635 ^{n , 10 g of the carbon black known under the name" Vulcan XG72R W,} 12 g of a polyester, produced by reacting dimethyl terephthalate with a mixture of 2 m- Butyi-2-ethylpropane-1> 2 ~ diol and ethylene glycol, replacing 2 * 5 mol% of dimethyl terephthalate with pyromellitic dianhydride, also 2g of the surfactant known under the name "Amine C" and 178g of methylene chloride for 16 hours in a ball mill Mixed using balls of 3.175 mm in diameter. The Beschlohtungsmasse obtained was then applied to one of an approximately 76 / i thick polyethylene terephthalate film layer existing support! whereupon the obtained layer was dried. The surface resistivity of the dried leak sheet obtained was measured and found to be 80 ohms per area, that is, extremely low.

In further experiments it could be shown that d & ß by adding of silver * or nickel particles as electrically conductive Fabric according to the given dimensions of the specific "Ifo resistance from one of the souls made out of it could be further degraded.

Example 7
The procedure at the same level in Beiepitl IT was repeated

with the exception that no soot and only two grams of the specified Polyesters were used as a binder for the graphite. The surface resistivity of a The lacquer layer produced from the coating compound obtained was 100 ohms / surface area.

Example VI

The procedure described in Example IV was repeated except that no graphite, and 10 g of the polyester as a binder for the carbon black used wur- \ the. The specific surface resistance of a lacquer layer produced from the specified coating composition was 200 ohms per area.

Example VII
(Comparative example)

The procedure described in Example IV was repeated except that neither graphite nor carbon black was used. The specific surface resistance of a paint layer produced from the specified coating composition was immeasurably high, that is to say it was more than 10 ohms.

Ö09837 / 1963

Claims (12)

'■; ■■. . ^: »■ ■■ '. ■■:. -; PATENT CLAIMS Electrophotographic recording material, consisting of a layer support having an electrically conductive layer, at least one photoconductive applied thereon Layer and optionally intermediate and / or top layers, characterized in that it is a lacquer layer (or lacquer coating) of a resinous film-forming polymeric binder and an electrically conductive dispersed therein Has substance that the electrically conductive layer electrically conductive with a device specifying a potential connects. 2. Electrophotographic recording material according to claim 1, characterized in that the lacquer layer on one of the Edges of the electrophotographic recording material is applied. 3. Electrophotographic recording material according to Claims 1 and 2, characterized in that in the lacquer layer present, electrically conductive material made of graphite, electrically conductive metal, nickel, a mixture of graphite and electrically conductive carbon black or a Genrissh made of graphite, electrically conductive carbon black and silver. ¹ J. Electrophotographic recording material according to Claims 1 to 3, characterized in that the binder of the lacquer layer consists of a polyester or polyolefin. 5. Electrophotographic recording material according to claims 1 to 4, characterized in that the lacquer layer is about 0.1 to 100 parts by weight per part by weight of binder Contains electrically conductive material. 6. Electrophotographic recording material according to Claims 1 to 5, characterized ₄ that the lacquer 009837/1963 layer of one, as an electrically conductive substance, a mixture of graphite and an »electrically conductive one Carbon black containing dispersion, the electrically conductive carbon black about 0.5 to 2.0 parts by weight per part by weight Contains graphite, preferably 1 part by weight of graphite and 1.2 parts by weight of polymeric binder. 7. Electrophotographic recording material according to claim 6, characterized in that the polymeric binder from the in the implementation of dimethyl terephthalate, 2-m-butyl-2-ethylpropane-1,3-diol, ethylene glycol and ψ Copolyester formed by pyromellitic dianhydride. 8. Electrophotographic recording material according to Claims 1 to 7, characterized in that the lacquer layer has a resistivity of less than about 10 ^ ohms per square. 9. Electrophotographic recording material according to Claims 1 to 8, characterized in that the layer support consists of a polyethylene terephthalate film. 10. Electrophotographic recording material according to claims 1 to 9, characterized in that the elec- - Trically conductive layer applied to the substrate or electrically conductive metal salts incorporated therein or vapor-deposited onto the substrate Metals. 11. Electrophotographic recording material according to claims 1 to 10, characterized in that between . an adhesive layer is arranged on the electrically conductive layer and the photoconductive layer. 12. Electrophotographic recording material according to claims 1 to 11, characterized in that the for Grounding used consists of a metal plate. 009837/1963