DE2108080A1 - Electrophotographic process - Google Patents

Description

PATENT ADVOCATE !:

DR. EWIEGAND DIPL-ING. W. NIEMANN 2108080

DR. M. KÖHLER DIPL-ING. C GERNHARDT

MDNCHEN HAMBURG

TELEPHONE = 555476 8000 MONKS 15,

TELEGRAMS: KARPATENT NUSSBAUMSTRASSE 10

18th February 1971

W. 40 376/71 13 / Loe

Fuji Photo Film Co., Ltd. Ashigara-Kamigun, Kanagawa (Japan)

Electrophotographic process

The invention relates to a method for transferring and fixing an electrophotography Toner image using a heat-sensitive adhesive tape without any loss or degradation the image quality.

Conventionally, an electrophotographic toner image has been transferred electrostatically or by means of pressure. A toner image obtained by electrophoretic development is not completely transferred to another surface due to the extremely fine particle size of the toner, which tends to be introduced into and strongly retained in the minute irregularities present in the developed surface. Up to now, "the transfer of such an image3 has been carried out in Maclian terms. With the developed surface, a porous sheet that effortlessly supports the ilräfmrllilsaigkiQxt doa 'Snty icicle rs afoiiorbisrt,

TG333S / J379

brings touch while it is still moistened with the developer. On the other hand, partial or fractional transfer of an electrophoretically developed image has been achieved by using a solvent * that contains those contained in the developed image _; resinous component can dissolve, but does not dissolve the photoelectric conductive layer, uniformly apply it, and then superimpose a porous transfer sheet on the layer, thereby making the image sticky and adhering to the transfer sheet. Although these procedures are now in practical use in the manufacture of a contact copy model or stencil for diazo printing in the office copy sector, perfect toner transfer is hardly expected to occur. Therefore, these procedures can only be used for halftone or liner images. Improved operation is required for perfect transmission of a picture with continuous sound without any loss of picture quality,

It is therefore an object of the invention to provide an improved toner transfer method that does this Meets requirements »

According to the invention, there is provided a new method of transferring and fixing a toner image formed by the electrophoresis development of an electrostatic latent image on a photoelectrically conductive insulating layer according to any of the working methods known in the art of electrophotography waraseimti actllclies adhesive tape on a one

109836/1379

Photoelectrically conductive, wound toner image carrying Layer pressed so that a strong bond is formed between the toner image and the adhesive, whereupon the adhesive tape is peeled off from the layer and the adhesive tape carrying the toner image is layered is applied to a final substrate to form the final product (copy). The method according to the invention is characterized by the following features:

(1) The toner image formed by the electrophoretic development contains a thermoplastic resinous material; M.

(2) the resinous material in the toner image has a lower softening point than both the heat-sensitive adhesive coating of the adhesive tape and the photoelectrically conductive layer *,

(3) the adhesive transfer of the toner image

is at a temperature above the softening point of the toner image (i.e., the resinous material), but below the softening points of the adhesive and the photoelectrically conductive layer carried out;

(4) the layer formation from the adhesive tape and the " final substrate is executed at a temperature at which the adhesive of the tape is in melts to such an extent as to form a strong bond with the substrate surface.

The practical implementation of the method according to the invention is very simple, although from the above description it might appear as a complex, · ', - wherein according to the invention it is possible to carry out a toner transfer without. 3ed.a loss of visual quality is possible

188836/1379

will produce an image on any desired type of substrate with a glossy, fine appearance substantially the same as that of a conventional silver halide photographic copy. It should be noted that in dnhi method of the invention "which remains according to the amount of njcäc transferred to the adhesive tape TonerF on the photoconductor layer is usually negligibly small ie <;.

The invention is explained in more detail below with reference to the drawing.

Fig. 1 2eigt a cross-sectional view of a photoelectrically conductive recording material ^ which is a Toner image carries.

Fig. 2 shows a cross-sectional view of an arrangement comprising the recording material of Fig. 1 and a heat-sensitive adhesive tape,

Figure 3 illustrates the adhesive tape bearing the toner image adhering vigorously to a final support is bound.

With reference to Fig. 1, the reference numeral denotes a photoelectrically conductive recording material, which carries a toner image 2, which is electrophoretically deposited on the light-electrically conductive insulating layer 11, which is provided on a pad 12 has been complied with. The toner image 2 comprises a colored pigment or pinene dye and a thermoplastic resin / Tp / i Material. Suitable pigments need to eat carbon black,

BATH ORIGINAL

109836/1379

Phthalocyanine Blue, Brilliant Carmine 6B, Benzidine Yellow, and Phthalocyanine Green, with Alkali Blue (Aniline Blue) being 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, pentaerythritol ester of natural resin, xylene-formaldehyde resin, copolymers with a Content of alkyl acrylate, polystyrene, mixed polymer with a content of styrene, hydrocarbon resin, ethyldellulose, vegetable oils, vinyl chloride / vinyl acetate mixed polymer, polyamide d

resin or the like Many of the substances listed above are known as thermosetting resins. However, the term "thermoplastic" as used herein is so to understand that these resins have thermoplasticity or when heated in the step of toner transfer softens.

Among these resins, those resins having softening points below 9CFC are usually preferred .

The term "thermoplastic egg" used here

properties "mean ^ apart from the strict techni- ™ see definition, the characteristic that the behavior of a Heat softening is exhibited in carrying out the image transfer process, although Most of the alkyd resins and epoxy ester resins are classified as thermosetting materials.

109336/1379

The toner image transfer according to the invention cannot be successfully carried out with a toner image which contains an Alkyd ™ (alkyl) or epoxy ester resin and which is kept in air prior to the transfer process was because curing of the resin by oxygen took place and the resin accordingly its thermoplastic Has lost ability.

Many of the commercially available developers contain antioxidants to help harden thermosetting agents Resins that are contained in it prevent, making the hardening remarkable after development is delayed.

From a practical point of view, however, the position 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 for Regulation of the elokfcrophoretic properties of the dispersing particles In liquid developer and used to give the developed image its own fixability to confer, these resinous materials Lii in many cases together with non-ioniochen or anion! see surfactants or others Additives are used. In the practical In practice of the invention, the composition, i.e. resinous material and other additives have a softening point below that specified above j / show locales. It should be mentioned in passing that 3 in part of the resinous materials that are in the carrier liquid are believed to be highly soluble with the surface of the dispersed pigment as a result of a iMixing the pigment with such resinous ones Material.ia η are connected «Dahsr can in the

10 9 8 3 6/1379

in most cases a developed toner image will include resinous materials.

In Fig. 1, the reference numeral 3 denotes a non-toner or background area. The structure of the photoelectric conductive layer is explained in more detail below.

Fig. 2 illustrates in cross section a structure consisting of a heat-sensitive adhesive tape 3 and the developed photo-conductive recording image 1 shown in FIG. The ™

two sheet-like or sheet-like materials are in intimate mutual contact under a suitable Maintained temperature condition at which only the toner image is softened and an adhesive transfer from the photoelectrically conductive ^ surface 11 to the adhesive coating 31 »the on a pad 32 is present, learns. The heat-sensitive adhesive coating 31 has a higher one Softening temperature than the toner image. The double layer arrangement is sufficient with heat and pressure Level to cause softening and transfer of the toner image, but not Er- J

softening of the coating 31 to effect, the feed of heat and pressure with the help of a pair of heating rollers, an electric iron or others Means takes place, with the essential part 21 of the toner image 2 on the coating 31 leaving behind a residual image 22 on the photoelectrically conductive layer 11 is transferred. Here, of course, the photoelectrically conductive layer 11 neither soften nor adhere to the adhesive via Zug. Since the photoelectric conductive layer 11 only has to meet this single condition, any one with a pre-

109836/1379

ORIGINAL BATHROOM

- ο -

proportional softening point for the purposes can be used according to the invention. Typical examples of photoelectrically conductive layers include:

(1) Mixtures of an insulating resin-like binder and a finely divided photolexter from the group of Zinfcoxj'd, Titaniumdioxid, Cadmiumsulfid , Zinkulfid, Zinccedmiumsulfid, Cadmiumamid, Calcium-Strontiumulfid, Mercury-iodide, Mercury-iodide, Mercury sulfide, arsenic sulfide, indium sulfide (arsenousdisulfide), arsenic sulphide, antimony trisulphide, cadmium sulphurelc-nide, and halos thereof

(2) coatings deposited by means of vacuum ¹ which comprise selenium, selenium telluride, Slen-Schvefel, selenium-AvBtm or the like;

(3) coatings containing inorganic photoconductors, see B. Zinc oxide or zinc sulfide and a glue binder include, and

(4) Coatings - that contain "organic photo conductors."

Suitable organic photoelectrically capable compounds include triphenylamine, 2,4-bis-44,4'-dläthylamxnopher.yl) -1,3 _f 4-oxadiazole, II-isopropylcarbazole, trlplienylpyrro3, 4 _f 5-I) iplierjyliinidazolidinon, 4,5- Diphenylimidasolidinthione, 4 ₁ 5-Bi p- (4 ^f -amiriophenyl) ■ Imldazolldinoji, 1,5-DicyanonaphthplI :: -, 1,4 ~ Dicyanon ^ iithalin »Aminophthalodi iiitrll, IJitrcphthalodlnltrll, 1,2,5 ί 6-Tetrazacyclooctatetraen- (2,4,6,8), 2-mercapto

109836/1379

benzothiazole, 2-phenyl-4-diphenylidenoxazolone, 6-hydroxy-2,3-di- (p-methoxyphenyl) -benzofuran, 4-dimethylaminobenzylidenebenzohydrazide, 3-benzylidenaminocarbazole, Polyvinylcarbazole, (2-nitro-benzylidene) -p-bromaniline, 2,4-diphenylquinazoline, 1,2,4-triazine, 1,5-diphenyl-3-methylpyrazoline, 2- (4'-diraethylaminophenyl) benzoxazole, 3-aminocarbazole phthalocyanine and mixtures thereof. For the purposes of the invention, such organic, photoelectrically conductive materials are accessible, as described in Japanese laid-open publications 8553/66 (corresponding to US Pat. No. 3,418,116), 19751/67, 25230/67, 2629/68, 24753/68 and 27588/68.

When a light-electrically conductive layer a thermoplastic, resinous material as an insulating binder (the first group) or as a photoconductor (the fourth group), care must be taken that the softening point condition of the layer is met, one of the most important Ways to meet this condition is to crosslink or cure the resin so as to to form a three-dimensional molecular lattice structure.

Suitable thermosetting resins include alkyd resins modified with vinyl monomers (styrene, acrylic esters) Alkyd resins, epoxy ester resins, polyurethanes, unsaturated Polyester, phenol-formaldehyde resins, thermosetting acrylic resins, melamine-formaldehyde resins, silicone-alkyd resins.

109836/1379

A photoelectrically conductive layer is preferred used with a less tacky surface, for example with a release or release coating made of a Silicone is provided, as indicated, for example, in Japanese Patent Application No. 28037/69, or it is a photoelectrically conductive layer uses a fluorocarbon resin as a binder or a surface release coating contains.

Particularly preferred compositions ^ can be obtained with photoelectrically conductive layers that contain photoelectrically conductive zinc oxide or cadmium sulfide dispersed in a binder consisting of an alkydepoxyester or vinyl copolymer containing primary OH groups, and polyisocyanate as a hardening agent for the former. One of the main characteristics of such layers is the ability to reproduce images with low contrast tone. Even when the binder is thermoplastic, the photo-conductive layer sometimes shows little tendency to adhere to the adhesive coating due to the high concentration of the incorporated photo-conductive particles, thereby enabling the practice of the invention.

On the other hand, plasticized, organic photoelectric, conductive layers for the purposes according to the invention due to the low melting point of • Are not suitable for plasticizers. To this difficulty To avoid this, one can use a rigid support, e.g. a metal drum, metal plate instead of a flexible carrier, such as paper, and you can use an organic photoelectrically conductive layer, which is free from plasticizers.

109936/1379

The tape bearing the final image can be coated onto a flexible support e.g. paper or plastic film such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, Polyvinylidene chloride, regenerated cellulose, cellulose diacetate, cellulose triacetate, nitrocellulose, Cellulose acetobutyrate, polycarbonate, polyethylene terephthalate or the like.

Of these, polypropylene, cellulose acetate, cellulose acetate butyrate and polyalkylene terephthalate are particularly preferred due to the clarity and resistance to discoloration after the comparison M drive according to the invention for the creation of elektrophbtographisehen copies of excellent quality is provided.

In addition, however, cloudy or opaque documents or carrier materials such as metal foils, Paper or textile materials, for use reach.

The thickness of the carrier film or the base for the adhesive tape can be in the range from 5 to 200 microns and especially from 3 to 30 Ilikron litgtn J

The v; low-sensitive or hot melt adhesive coating 31 in Fig. 2 may be of any known in the art approach with due consideration of the softening point and the compositions of the toner and the photoconductor layer which is to be connected thereto consist _T.

109836/1379

The heat sensitive or hot melt adhesive coating may comprise a low molecular weight component selected from the group consisting of coumarone-indene resin, Natural resin and its derivatives, mineral oil, wax, petroleum hydrocarbon resin, vegetable wax, Terpene resin, alkyd resin and thermoplastic phenol-formaldehyde resin is chosen.

The coating can also be used as a component in providing internal strength to the adhesive layer Ethyl cellulose, polyvinyl acetate, polybutyl methacrylate, Polyethylene, Ethyl en-Vinyü acetate-I-II schpolymerisat, Polystyrene, styrene melt polymers and Contain polyisobutylene; Recently, polyamide, polyamide derivatives and polyvinyl acetate have been increasingly used. A composition of the heat sensitive Adhesive is e.g. in "Handbook of Adhesives" by Skeist, published by Reinhold PublishinjCo. (1962), pages 44? to 451.

Usually the heat sensitive coating begins to ^{soften in the vicinity of about 80 1} C "u, with sufficient flow exhibiting above 90". On the other hand, a toner image contains components such as vegetable oil or long oil modified alkyd resin that melts or flows below 80 "C. Therefore, the transfer of the toner image on the adhesive coating may be carried out successfully at 70 to 9O ⁰ C under suitable pressure and heating time conditions. This, of course, is a standard measure for the establishment of transfer working conditions. When the adhesive coating, which is provided on a substrate (eg polyalkylene terephthalate) which is resistant to high temperatures, melts at a higher temperature.

109836/1379

the transfer can be carried out at a higher temperature -will. In summary, it is therefore stated that the temperature of the transfer is chosen can be to meet the conditions outlined above.

3 illustrates the tape of adhesive carrying the toner image transferred thereon, which is strongly bonded to a final carrier 4. During the fixing process, the coating 31 is heated in order to obtain sufficient melting and strong adhesion to the surface of the carrier 4. The carrier 4 can be made of any material, for example paper, cloudy or opaque plastic, metal plate or the like. exist according to the different uses. If the support is cloudy, the final copy can be viewed by means of reflection. If a transparent support is used, transparency for a projector from above or a slide plate will be seen. The transparent carrier can be made of materials suitable for the underlay 32 gsoigrivi; are.

The method according to the invention is not only for the achievement of a monochromatic copy but also for the production of a multicolor copy Transfer of a multicolor image formed by an electrophotographic copying technique became applicable.

The invention is explained below with reference to ίί'-υ \ - ~ play explained in more detail.

10983 * 713 7 9 '^

example 1

In this example, a commercially available heat sensitive adhesive tape was used,
which consisted of a 12 micron thick polyethylene terephthalate film coated on one surface with polyvinyl acetate as a main component. This coating softened near about 10OG.

An electrophotographic plate or sheet was made by forming an electroconductive electrophotographic layer on a 100 micron thick baryta paper which was provided with an auxiliary coating of an electroconductive material. The photoelectrically conductive coating consisted of 100 parts of Zinko :: yd, 14
Parts of styrenated alkyd resin and 6 parts of Polylsoo / anat, the thickness of the coating being 10 microns
Dry basis was, U-Even this layer at 50 ^c 0
was heated for a long period of time to cure the alkyd resin, this layer shows: at
10OC neither a softening nor a sticky mouth.

The photosensitive plate or the light-sensitive sheet was loaded old uniform to vollständigü Dark approximation electrical ·> s tatischen charge of negative polarity, with a
exposed optical image and then behandalt with a liquid developer prepared by dispersing 1 part of a Offsetdruckfaruci commercially available (marketed untsr the Ifarenbezeichnung 'Piano Blue "by Fuji Phofco ii'iliä Co., Ltd.) in 400 parts of kerosene under irradiation with Ultrasonic waves had been produced,

109836/1379

When a developer electrode was used during development, a lifelike reproduction of the tone gradation was obtained. The treated plate or sheet was rinsed with an isoparaffin solvent, then substantially dried, and then overlaid with the adhesive tape such that the adhesive coating faced the toner image. The assembly was inserted between a pair of stainless steel rollers or cylinders ^{kept at 80 ° C.} The sheets passed through could very easily be peeled off from one another without any tendency to block, with the toner image being transferred to the adhesive coating alone. While the maximum density of the developed image before transfer was 2.0, the density of the same area after transfer had decreased to 0.3. No photo-conductive layer was transferred to the background area. The adhesive tape bearing the toner image was then applied in a layered manner to the baryta coating of a photographic baryta paper approximately 120 microns thick and the assembly was passed between a pair of rollers heated to 13Οΐ

guided. The final copy thus made possessed ™

a maximum density of 1.8 (reflection density).

Example 2

An electrophotographic layer containing 100 parts of cadmium sulfide and 30 parts of a thermosetting acrylic resin which was ^{cured at 20O 5} C was formed on an aluminum tube. This material became a

109836/1379 ^

Corona discharge and then subjected to image exposure. A liquid developer that works in the was prepared in the following manner, was applied to the pipe.

Manufacture of the developer:

The following ingredients were mixed thoroughly using a high speed mixer:

Microlith Blue AG-T 200 mg

a paint or varnish made by boiling modified with natural resin Phenol-formaldehyde resin with flaxseed oil was obtained 400 mg

Toluene 10 ml

The phenol-formaldehyde resin used here, modified with natural resin, is such a resin as it is used for printing inks and has a viscosity of about 100 cp. This resin is in kerosene soluble but not in acetone, linseed oil or isoparaffinic acid Hydrocarbon solvents. It dissolves completely in cyclohexane. Which The resulting bluish concentrated paste was in a mixture of 250 ml of kerosene, 700 ml of cyclohexane and 50 ml of flaxseed oil dispersed.

The developed material was in Isopar E (an isoparaffinic solvent with a KB value of 29 manufactured by Esso Standard Oil Co.) rinsed repeatedly.

109836/13 79

Microlith is a pigment that has been rinsed with a hydrogenated natural resin ester * (sold by Ciba Ltd.). A heat-sensitive adhesive tape made of a 20 micron thick polypropylene film coated with an adhesive essentially containing an aliphatic polyester resin was pressed onto the surface of the developed material in such a way that the adhesive coating faced the pipe surface, at a temperature of 75 ^° C was applied. Once this is KH> fabric coating is not activated to about 100 ⁰ C, the tape could easily be removed from the surface, with only the toner image was transferred to the adhesive coating. The tape carrying the toner image was then sandwiched with a 100 micron thick polyethylene terephthalate film and vigorously bonded to it at 11CPC to form transparency.

Example 3

This example was made using a zinc oxide coating and a set of color firing stimulants formed a multicolor image.

First was a set of positive color release banners from a dye photographic negative Made using a blue, green and red filter. Each of these banners is shown below as yellow copy positive, magenta copy positive or Marked cyan copy positive.

10ÜÖ36 /

The electrophotographic zinc oxide used material was made by using an aluminized Polyethylene terephthalate film with a layer, Consists of 100 parts of zinc oxide, 20 parts of epoxy ester, one drained. or dehydrated Castor oil fatty acid and 0.2 parts of cobalt naphthenate, coated and thermally hardened said layer became. -

A sheet of the film thus produced was negatively charged in the dark, exposed with the magenta copy positive, and developed with the magenta developer described below. The development was carried out with sclerosing a developer electrode for 2 minutes. Then the sheet was briefly subjected to a stream of Isopar S at high speed, passed between a pair of squeezing rollers for squeezing off the rinsing liquid and dried therein with a drying device. This "operations were under unpffce ^ Kl;? A light running" The same sheet was HiiiHtt asgiib.Lj g liidiiüi, with the Cyankopierpositiv bcüichfcet uad in sinsn Cyanenbwlckler, as indicated below, submerged. The other operations were rholt WME in similar ILehoc ^r i! Eiä3. Finally, the loading · ^; ■ liciituxig with dsm öalbkopierpositiv and development · - mLc, a Gelbiuifcy / run Ickler, It was a 'ii ^ hrfarbenkppie dur "ch the ßinkopierarbeitsv / else erha11 at (Übs rkoρ ting).

SAD OHJOfNAL

1 0 9 -U, / 1 3 7 S, .... , ..

Manufacture of the developer: Magenta developer "

A concentrated paste prepared by mixing the following components was used in a mixture of 200 ml kerosene and 800 ml cyclo hexane dispersed:

Brilliant Carmine SB 200 mg

With soybean oil (long oil) M

modified alkyd resin 400 mg

Polymerized flaxseed oil 100 mg cyan developer:

A concentrated paste obtained by mixing the ingredients shown below was used in the gMchen mixture as above for the magenta developer indicated, dispersed;

Phthalocyanine Blue 200 mg

Epoxy ester of dehydrating

castor oil fatty acid

of medium oil length 400 mg

Natural resin modified
Phenol formaldehyde resin 100 mg

Polymerized flaxseed oil 100 mg yellow developer:

A concentrated paste obtained by mixing the following ingredients was made into the same Carrier liquid, as indicated above, dispersed:

109836/1379

A yellow pigment with the formula given below:

^2o °

A varnish or paint made by boiling phenolic aldehyde resin modified with natural resin with linseed oil 800 mg of polymerized flaxseed oil 100 mg was obtained

Each toner image softened

The sensitive tape used in Example 2 was reapplied and the transfer of the iridescent color image was carried out in Iy- ³ J 8O ⁷ C. The tape carrying the toner image was applied in t'chiclite-nordnuug to a baryta paper.

SAD OfHGlNAk, 109836 / 137Ö

Claims (6)

Pa needs (ij / 'Electrophotographic process wherein an electrostatic latent image is formed on a photoelectrically conductive insulating layer, the latent image is developed with a liquid developer comprising a finely divided charged toner dispersed in an insulating liquid, on the resultant Toner image a heat sensitive adhesive coating is pressed from a heat sensitive tape, the tape is peeled from the layer with the toner image transferred to the adhesive coating, and finally the tape is laminated onto a final carrier to affix the image thereon, characterized in that a toner image with a content of thermoplastic, heat-sensitive, resin-like material is formed during liquid development, the softening point of the thermoplastic, hard-like material being lower than the softening points of the heat-sensitive adhesive coating and d-jv lishbeltfktrLscih conductive layer which Übai ^s r; raf: ung (Ncur: .lLa adhesion) of the toner image on the hifc ^ smpf.Lndllcheu coating executes at a temperature at evading * softens the toner image while there is substantially no softening of the heat-sensitive coating and layering the tape carrying the toner image on the final support at a temporary door at which sufficient softening of the heat-sensitive adhesive coating takes place, SÄD OftlGlNAi- Ϊ5 -J sv 2) Method according to claim 1, characterized in that that an adhesive tape is used, which is a transparent plastic film, consisting of polyethylene terephthalate, Polypropylene or cellulose acetate, 3) Method according to claim 1, characterized in that a photoelectrically conductive coating is used, which comprises photoelectrically conductive zinc oxide and a resin binder. 4) Method according to claim 1 or 3 »characterized in that that the photoelectrically conductive coating is a hardened thermosetting resinous one Contains binding agent. 5) Method according to claim 1 »characterized in that that the sensitive adhesive coating of the Adhesive tape at a temperature in the bar area of 70 to lOOFC softened. 6) yeri'ahrsn also claim J, characterized in that the erid ^ üi.r.iga carrier consists of a transparent plastic film.