DE2108080B2 - Electrophotographic process - Google Patents

Description

F i g. FIG. 2 shows a cross-sectional view of an arrangement comprising the recording material according to FIG. 1 and a heat sensitive adhesive tape comprises;

F i g. Figure 3 illustrates the adhesive tape bearing the toner image being applied to a final carrier is strongly bound.

With reference to FIG. 1, the reference numeral 1 designates a photoconductive recording material which carries a toner image 2 made from a liquid dispersion developer. The toner comprises a colored pigment or dye and a thermoplastic resinous material. Suitable pigments include carbon black, phthalocyanine blue, CI no. 74160, brilliant carmine 6 B, CI no. 15850: 1, benzidine yellow, CI no. 21090, and phthalocyanine green, CI no. 74260, whereby alkali blue (aniline blue), CI no. 4 ⁿ 765, is an example of a suitable dye. Thermoplastic, resinous materials contained in the toner image include vegetable oil-modified alkyd resins (medium to long oil length), epoxy ester resins, natural resin-modified phenol-formaldehyde resin, hydrogenated natural resin ester with glycerol, pentaerithritol ester of natural resin, xylene-formaldehyde resin, ivic polymers with a Content of alkyl acrylic, polystyrene, mixed polymer with a content of styrene, hydrocarbon resin, ethyl cellulose, vegetable oils, vinyl chloride-vinyl acetate mixed polymer, polyamide resin or the like. Many of the substances listed above are known as thermosetting resins. However, the term "thermoplastic" as used herein is understood to mean that these resins are thermoplastic or may be softened when heated at the step of toner transfer.

Among these resins, those resins having softening points below 90 ° C are common preferred.

The term "thermoplastic properties" used here means apart from the strict technical Definition, the characteristic that the behavior of a softening under the action of heat during execution of the image transfer process, although most of the alkyd resins and epoxy ester resins classified as thermosetting materials.

The toner image transfer according to the invention cannot be successfully carried out on a toner image containing an alkyd or epoxy ester resin and in air before the transfer process had been held, ^ a hardening of the resin by oxygen has taken place and the resin accordingly be? has lost thermoplastic ability. Many of the commercially available developers included Antioxidants to harden thermosetting resins contained therein prevent, thereby noticeably delaying curing after development.

From a practical point of view, however, the statement made above is only an overly precise one Consideration, as the transfer process will take place a few hours after development. Usually these resinous materials are used to control electrophoretic properties of the dispersing particles used in liquid developers and to give the developed image a self-fixing ability these resinous materials in many cases together with nonionic ones or anionic surfactants or other additives are used. In the In practicing the invention, the composition, i. H. resinous material and others Additives, have a softening point below the value given above. Is casual

mention that some of the resinous materials which are soluble in the carrier liquid are believed to be strong with the surface of the dispersed pigment due to prolonged mixing of the pigment are associated with such resinous materials.

ίο Therefore, in most cases, a developed Toner image include resinous materials.

In Fig. 1, the reference number 3 denotes a toner-free or underground area. The structure of the photoconductive layer is explained in detail below.

F i g. Fig. 2 illustrates, in cross section, a structure comprised of a heat sensitive adhesive tape 3 and the recording material 1 carrying the toner image shown in FIG. 1 is shown. the

ao two sheet-like or web-like materials are kept in intimate mutual execution under a suitable temperature condition at which only the toner image is softened and a transfer from the photoelectrically conductive surface 11 to the adhesive coating 31, the ai. ' a pad 32 is present, learns. The heat-sensitive adhesive coating 31 has a softening temperature higher than that of the toner image. The bilayer assembly is supplied with heat and pressure sufficient to cause softening and transfer of the toner image, but not to cause softening of the coating 31, the application of heat and pressure by means of a pair of heating rollers, an electric iron or other means, the essential part 21 of the toner image 2 being transferred onto the adhesive coating 31, leaving a residual image 22 on the photoconductive layer 11. Here, of course, the photoconductive layer 11 should neither soften nor adhere to the adhesive coating. Since the photoconductive layer 11 only has to meet this single condition, any one with a relatively high softening point can be used for the purposes according to the invention.

can be used. Typical examples of photoconductive layers include:

1. Mixtures of an insulating resinous binder and a finely divided photoconductor from the Group of zinc oxide, titanium dioxide, cadmium

sulfide, zinc sulfide. Zinc cadmium sulfide, cadmium selenide, Calcium strontium sulfide, mercury iodide, mercury oxide, mercury sulfide, indium trisulfide, gallium iristienide, Arsenic disulfide, arsenic trisulfide, antimony trisulfide, cadmium sulfoselenide, and mixtures thereof;

2. Coatings deposited by means of vacuum, the selenium, selenium telluride, selenium-sulfur, selenium-arsenic or the like includes.!;

3. Coatings containing inorganic photoconductors, e.g. B. zinc oxide or zinc sulfide and a glass binder include, and

4. Coatings containing organic photoconductors. Suitable organic photoelectrically conductive compounds include triphenylamine, 2,4-bis- (4,4'-diethylaminophenyl) -l, 3,4-oxadiazole, N-isopropylcarbazole, Triphenylipyrrole, 4,5-diphenylimidazolidinone, 4,5 - diphenylimidazolidinthione, 4,5 - bis - (4 '- aminophenyl) -imidazolidinone, 1,5-dicyannaphthalene, 1,4-di-

5 6

: yannaphthalene, aminophthalonitrile, nitrophthaloid chloride, regenerated cellulose, cellulose diacetate,

dinitrile, 1,2,5,6 - tetrazacyclooctatetraene - (2,4,6,8-), cellulose triacetate, nitrocellulose, cellulose acetobuty-

2-mercaptobenzothiazole, 2-phenyl-4-diphenylidene rat, polycarbonate, polyethylene terephthalate or the like.

oxazolone, 6-hydroxy-2,3-di- (p-methoxyphenyl) -benz- These are polypropylene, cellulose acetate, cellulose furan, 4 - Üimethylaminobcnzylidenbenzhydrazide, 5 lulose acetate butyrate and polyethylene terephthalate in particular

3 - Benzylideneaminocarbazole, polyvinylcarbazole, particularly preferred due to the clarity and convenience

(2-nitro-benzylidene) -p-bromoaniline, 2,4-diphenyl- resistance to discoloration,

quinazoline, 1,2,4-triazine, l, 5-diphenyl-3-methylpyra- In addition, however, cloudy or opaque

zolin, 2, - (4 '- dimethylaminophenyl) - benzxazole, transparent documents or carrier materials such as Me-3-aminocarbazole phthalocyanine and mixtures of metal foils, paper or textile materials, for application

from. For the purposes of the invention, such an organization has been reached.

niche, photoelectrically conductive materials accessible, the thickness of the carrier film or the base for

as described in Japanese patent application 8553/66 the adhesive tape can be in the range of 5 to 200 micro-

(corresponding to US Pat. No. 3,418,116), 19751/67, meters and in particular from 3 to 30 micrometers 25230/67, 2629/68, 24753/68 and 27588/68 are described 15,

are. The heat-sensitive or hot-melt adhesive

When a photoconductive layer has a thermal coating 31 in FIG. 2 can be from any in the

plastic, resinous material known as an insulating binding technique under reasonable conditions

medium (the first group) or as a photoconductor (the fourth consideration of the softening point and the to-group) contains, care must be taken that the ao compositions of the toner and the photoconductive

Condition with regard to the softening point of the capable layer to be connected to it,

Layer is fulfilled, with one of the most important possi- bilities.

possibilities of fulfilling this condition in that the heat-sensitive or hot-melt adhesive is to crosslink or cure the resin so that fabric coating can be a component of low a three-dimensional molecular lattice structure formed as molecular weight, comprised of the group of will. Cujr. \ Ron-linden resin, nutar resin and its derivatives,

Suitable thermosetting resins include alkyd mineral oil, wax, petroleum hydrocarbon resin, vegetable

resins, with vinyl monomers (styrene, acrylic esters) zen wax, terpene resin, alkyd resin and thermal

modified alkyd resins, epoxy ester resins, polyuroplastic phenol-formaldehyde resin is selected.
ethane, unsaturated polyester, phenol formaldehyde 30 The coating can also be used as a component for

Resins, thermosetting acrylic resins, melamine-formaldehyde- the granting of an internal strength to the adhesive-

hyd resins, silicone alkyd resins. layer of ethyl cellulose, polyvinyl acetate, polymetha-

A photoconductive layer containing butyl acrylate, polyethylene, ethylene-vinyl acetate is preferred little sticky surface used, the z. B. mixed polymer, polystyrene, styrene mixed polymer imit is provided with a coating of a silicone, contains 35 sate and polyisobutylene; recently become how this z. B. in the Japanese patent application to an increasing extent polyamide, polyamide derivatives 28 037/69 is specified, or a photoconductive and polyvinyl acetate is used. A cohesive one Layer used which is a fluorocarbon resin as a setting of the heat-sensitive adhesive is e.g. Am Contains binder or surface coating. "Handbook of Adhesives" by S k e i s t, published

Particularly preferred compositions can be found in 40 "by Reinhold Publishing Co. (1962), pp. 447 to 451,

can be obtained with photoconductive layers that are described.

Photoconductive zinc oxide or cadmium sulfide usually begins to soften the heat-sensitive coating pergoes in a binder consisting of one in the vicinity of about 80 ° C, being an alkyd resin, epoxy ester or vinyl copolymer. reaching flux above 90 ° C is exhibited, containing primary OH groups, and poly- 45 On the other hand, a toner image contains components, e.g. B. contain isocyanate as a curing agent for the former. alkyd modified with vegetable oil or long oil- One of the main characteristics of such layers of resin that melt or flow below 80C. Therefore, the ability to reproduce images with can transfer the toner image to the sticky low contrast tone. Even if the binder material coating successful at 70 to 90 ⁰ C under geeigthermoplastisch is, the photoconductive layer 50 shows Neten pressure and heating time conditions ausmanchmal a low tendency to stick to be performed. This is of course a standard measure of the adhesive coating due to the high concentration for setting the transfer working condition of the incorporated photoconductive particles. 55 (e.g. polyethylene terephthalate) is provided at

On the other hand, plasticized organic photo- a higher temperature melts, the overconductive Layers for the purposes according to the invention carried out at a higher temperature due to the low melting point of many. In summary, it is therefore stated. Plasticizer not suitable. To this difficulty that the temperature of the transfer was chosen so werzu you can avoid a rigid support, e.g. B. 60 den can to the above-mentioned conditions Metal drum, metal plate in place of a bend to meet.

seed carrier, such as paper, and one can use FIG. 3 illustrates the KJebstoffband that

an organic photoconductive layer, which carries free toner image transferred thereon, which is strongly attached to a

Plasticizers is to use. final carrier 4 is bound.

The tape, which carries the final image, can as 65 gang, the coating 31 is heated to a sufficient

Coating applied on a flexible support melting and strong adherence to the surface

be, for example, paper or Kunststoffoüe, such as polyethylene, of the carrier 4 to be obtained. The carrier 4 can be made from

Polypropylene, polystyrene, polyvinylchloride, polyvinyl- any material such as paper, opaque

or opaque plastic film, metal plate was placed between a pair of rollers set to 130 ° C

or the like were heated according to the various uses, passed through. The one made in this way

employment purposes exist. For an opaque support 4 final copy had a maximum density of 1.8

can be the final copy by means of reflection (reflection density),

be sought. A compact carrier can consist of 5 Be i s ρ i c I 2 be made of materials that are

lace ·> ?. are suitable. ^{On an} aluminum tube, an electro-The process according to the invention is not only a photographic layer, which contained 100 parts Cad for the achievement of a monochromatic copy, miumsilfid and 30 parts of a thermosetting acrylic but also for the production of a multicolor io resin, which at 200 ⁰ C was cured. This copy by transferring a multicolor image, the material was formed after complete darkening by an electrophotographic copy-in technique of a corona discharge and then an image exposure, applicable. subject. A liquid developer which was produced in the manner indicated below with reference to the invention is explained in more detail. ¹ S was applied to the tube.

Example 1 Preparation of the developer

In this example, a commercially available The following ingredients were thoroughly prepared using

uses heat sensitive adhesive tape that is mixed from a mixer at high speed: a 12 micron thick polyethylene terephthalate film, 20 Microlith Blue 4G-T, made by

which on a surface with polyvinyl acetate as the main treatment of phthalocyanine blue CI.

component was coated, existed. ^ This coating _{No. 74} J _{60 m} j _t a glycerol ester of a

Tung softened in the vicinity of about 100 ^° C. hydrogenated resin 200 mg

An electrophotographic plate or sheet - _{A Lac} | _<t the by boiling with material was made by applying a photoconductive 25 natural resin modified phenolic form layer on a 100 micrometer thick baryta paper obtained from aldehyde resin with flaxseed oil

was formed which _was coated with a Hiifsiiberzug from a 400 mg

electrically conductive material was provided. The photo-toluene 10 ml

conductive coating consisted of 100 parts of zinc

... j, .. τ -.-., ..,, ", r" tf ";,. rtps alkyd resin and 6 parts 30 The one used here, modified with natural resin

PoK ^ änäT'w ^ the Dfcke of the coating 10 micro-phenol-formaldehyde resin is such a resin as it

meters on a dry basis. After this is used for printing inks, and has a V.s-

Layer at 50 ⁰ C for a long period of time so a viscosity of about 100 cp. This resin is in kerosene

heated to cure the alkyd resin shows it to be soluble but not in acetone, linseed oil or

^ rhir-ht hpi Wc neither a softening nor a 35 isoparaffinic hydrocarbons. It dissolves in

Shift at iuu l. but cyclohexane completely. The resulting bluish

n ^ ' ^ß nphoto? elable recording material was borrowed concentrated paste was in a mixture

ä ^ ÄÄkdangleichuni with an equal of 250 ml of kerosene, 700 ml of cyclohexane and 50 ml

X Electrostatic charge dispersed from negative flaxseed oil

PnhnVit loaded with an optical image exposed 4 ° The developed material was in an iso-

and then treated with a liquid developer, paraffinic solvent with a KB value of

H ^ r, inrrh nknersieren of 1 part of a trade 29 repeatedly spooled.

Erl r \ See SsSruckflrbe in 400 parts kerosene Microlith 4G-T, produced by treating

Be traMunmT ultrasonic waves produced phthalocyanine blue CL no. 74 160 with a glycerine

DtMiaiiiui g ^ ester of a hydrogenated resin, is a pigment that with

When using a developer electrode during rinsing with a hydrogenated natural resin ester. on

, '. .. " ■ · _„ „(„ roffrpiie rendering the surface of the developed material became a

he ΐ.ΐ £ ϊί7ίΑ 'oaf SCSE ⁸ AU.- handy adhesive from a 20 M ^ «ichnunUtertalwurd" ^^

spins, abheOend ™ "^""™ J f SH _n containing polyester resin, pressed in such a way,

Sirg'an ^ ord'n "'S 3e,' _K .eb _s , S'g den that the adhesive coating of the chrome surface is ⁸ £" -

mgerung angeoranei, udu _Anor dnung was Interfere with a temperature of 75 "C applied

Toner image opposite · ^Die , ^An ^ ^r ™ ^^ _{us rust} . ^ rde After this adhesive coating up to about

C was introduced. 55 100 C is not softened, the tape could effortlessly

nia «Pr could be removed from each other from the surface, with only

Le ^Β νΖ ™? ™ »^ Ζ ab- transfer the toner image onto the adhesive coating

Jot because the toner image had been printed on it alone. The belt carrying the toner image became

B ₆₀ ϊγααϊϊκϊ

£ left? ΑαΤΕΪΑ density of 110 ^ C ^ Ug with this verbund ^ un, a trans equals Area after transfer to 0.3 absent-mindedly, taken. There were no photoconductive layers

H in these. Example, the under Ve ™ "ndu" g an "arrangement First a sow of positive color separation

transparent nils a color photographic negative made using a blue, green and red filter. Each of these banners will hereinafter referred to as yellow copy positive, magenta copy positive or cyan copy positive.

The zinc oxide photographic material used was prepared by consisting of an aluminized polyethylene tecphthalate film having a layer from 100 parts of zinc oxide, 20 parts of epoxy ester, a dehydrated castor oil fatty acid and 0.2 parts of cobalt naphthenate, coated and the said layer was thermally cured.

A sheet of the film so produced was negatively charged in the dark with the magenta copy positive exposed and developed with the magnetic developer described below. The development was carried out using a developing electrode for 2 minutes. Then it became Sheet briefly rinsed with an isoparaffinic solvent at high speed, passed between a pair of squeegee rollers for squeezing the flushing liquid and then dried with a drying device. These operations were carried out under subdued lighting. The same sheet was again negatively charged, exposed with the cyanoper positive and immersed in a cyan developer as shown below. The other operations were carried out in similarly repeated. Eventually the yellow copy exposure and development became positive executed with a gclb developer. Thereby, a multicolor copy was made by the copy-in operation preserved (copying over).

Manufacture of the developer
Magenta developer

A concentrated paste prepared by mixing the following components was made into a Mixture of 200 ml kerosene and 800 ml cyclohexane dispersed:

Brilliant Carmine 6 B CJ.-No. 15850: 1,200 mg
Alkyd modified with soybean oil

resin (long oil) 400 mg

Polymerized flaxseed oil 100 mg

Cyan developer

, ₅ A concentrated paste obtained by mixing the ingredients shown below was dispersed in the same mixture as mentioned above for the magenta developer:

Phthalocyanine blue C.I. 74160 200 mg

Medium oil length epoxy ester of dehydrated castor oil fatty acid 400 mg

Natural resin modified phenol-formaldehyde resin 100 mg

Polymerized flaxseed oil 100 mg

25th

Yellow developer

A concentrated paste obtained by mixing the following ingredients was added to the same carrier liquid, as indicated above, dispersed:

A yellow pigment having the formula given below

OCH ₃

CH,

C = O

Cl

'- NH - C - C - N = N -

N = N-C-C-NH

200 mg

A varnish made by cooking with
Natural resin modified phenol-formaldehyde resin obtained with linseed oil
became 800 mg

Polymerized flaxseed oil 100 mg

Each toner image softened at 8O ⁰ C.

The heat-sensitive tape used in Example 2 was applied again, and the transfer of the multi-color image was carried out at 8O ⁰ C. The tape carrying the toner image was applied in a layer arrangement to a baryta paper.

1 sheet of drawings

Claims (6)

1 2 transferred. A toner image obtained through electrophoretic development is not completely transferred to another surface due to the external 1. Electrophotographic process, wherein neatly fine particle size of the toner, which is added a charge image on a photoconductive layer 5 tends to be reflected in the minute irregularities in the formed and present with a liquid dispersion-developed surface, introduced winder made of finely divided, charged toner particles and firmly held in them. So far has been is developed, the transfer of such an image to the resulting toner image is mechanical the adhesive coating of a hot-melt adhesive tape is carried out, with the developed upper pressing being used The tape from the photoconductive surface becomes a porous sheet that easily forms the carrier liquid layer with the excess of the developer absorbed on the adhesive coating, brings into contact, carried toner image is peeled off and finally while it is still moistened with the developer. On the other hand, the ~ tape in layered onto a final support became a partial or fractional superposition is applied to make the image thereon an electrophoretically developed image fix, characterized in that 15 is sufficient by adding a solvent that contains the in dementwikdaß to dissolve a developer with toner particles from kelt image containing resinous component a thermoplastic, heat-softenable, resinous layer, but not the photoelectrically conductive layer like material used whose softening dissolves, evenly applies and then a porous over point lower than the softening points of the support sheet on the superimposed layer, heat sensitive adhesive coating and the 20 making the image sticky and to the overtraphotoconductive Layer is adhered to the transfer of the gung sheet. Although these workings now-toner image on the heat sensitive adhesive- more in practical use in manufacturing performs coating at a temperature at which a contact copy model or a contact the Toner image softens while essentially copying stencil for diazo printing on the sector are no softening of the heat sensitive adhesive of copying for office use is the occurrence Coating takes place, and the layer arrangement of a perfect toner transfer hardly to earth the toner image-bearing tape waiting for the end. Therefore, these procedures are only applicable for line valid carriers at a temperature applicable to images. It's an improved way of working which an arsufficient softening of the heat for a perfect transfer of a semitone sensitive Adhesive coating takes place. 30 images without any loss of image quality required. 2. The method according to claim ■, characterized thereby, the object of the invention is to create a draws that one uses an adhesive tape, improved toner transfer process that does this that a transparent plastic film, existing requirements meet. of polyethylene terephthalate, polypropylene or The method according to the invention is thereby Cellulose acetate, characterized as a carrier for the adhesive layer 35, that one has a developer with toner, particles made of a thermoplastic, heat-softening 3. The method according to claim 1, characterized by using a resin-like material, the drawing of which that the photoconductive layer has a softening point lower than the softening points Zinc oxide binder layer used. the heat sensitive adhesive coating and the 4. The method of claim 1 or 3, characterized in that 4 ° photoconductive layer is the transfer of the characterized in that the photoconductive layer comprises toner image on the heat sensitive adhesive cured thermosetting resinous bond coat at a temperature at which contains medium. the toner image softens while essentially none 5. The method according to claim 1, characterized in that the heat-sensitive adhesive coating is softened, the heat-sensitive adhesive coating takes place, and the layer arrangement of the toner train of the hot-melt adhesive tape at a temperature in the image-bearing tape on the final carrier in the range from 70 to 100 ⁰ C softens. at a temperature at which a sufficient 6. The method according to claim 1, characterized in that the heat-sensitive adhesive is characterized by softening, that the final carrier is a trans-coating. parent plastic film. 50 The practical implementation of the procedure according to the invention is very simple, albeit based on appear as a complex of the above description could, according to the invention, the execution of a toner transfer without any loss of image The invention relates to electrophotographic quality and wherein an image is made on any graphic process, a charge image being formed on a desired type of substrate with a glossy photoconductive layer and with a fine appearance essentially that of a liquid dispersion developer finely divided, common photographic silver halide copy charged toner particles is developed, on which is the same, is obtained. It should be noted that with the resulting toner image the adhesive ^{coating of a hot 6} ° the method according to the invention, the amount of adhesive tape is pressed, the tape of the photo-toner not transferred to the adhesive tape, the conductive layer with the on the adhesive coating the photoconductive layer remains, the transferred toner image is peeled off and is ultimately negligibly small.
lent the tape to a final backing in layers. The invention will be applied below with reference to the drawing arrangement to illustrate the image thereon in more detail. fix. F i g. 1 shows a cross-sectional view of a photo Conventionally, an electrophotographically conductive recording material having a toner image carries thermal toner image electrostatically or by means of pressure;