DE1915221A1 - Electrophotographic recording material - Google Patents

Description

Eastman Kodak Company, 343 State Street, Rochester,

New York State, United States of America

Electrophotographic recording material

The invention relates to an electrophotographic recording material, consisting of a substrate, an electrically conductive layer applied to the substrate, a barrier layer adjacent to the electrically conductive layer and a photoconductive layer adjacent the barrier layer.

The known electrophotographic copying processes, such as for example in US patents 2,221,776, 2,277 Γ13,

2 297 691, 2 357 809, 2 SS1 582, 2 825 814, 2 833 648, 3 220 324,

3 220 831, 3 220 833 b @ se! Hyi © ben v & rden, use electrophotographic Recording Qateri & lion, which are structured in such a way that it is based on an image exposure to electromagnetic radiation with the formation of a l & tontesi electrostatic charge image speak to. This is then processed in a specific manner for production can be used by permanent photocopying.

009844/1513

Particularly suitable for electrophotographic processes » Drawing materials generally have a multilayer structure. Such recording materials can be produced by making one beforehand with a layer of one electric senior. Material coated substrate with a layer coated from an insulating photoconductor layer. aside from that is between the electrically conductive layer and the ρ iotoconductor layer an insulating or barrier layer is arranged.

The barrier layer has the task of preventing the loss of charge in the absence to reduce an activating radiation. This loss of charge is commonly referred to as dark decay. on the other hand a suitable barrier layer must not prevent the proper discharge of charge in the presence of activating radiation. The barrier layer also helps reduce the power fluctuation © !! with repeated use of a recording material. Such a fluctuation in the performance of an electrophotographic Repeated use recording material is known by the name of "charge southing". The function one? The barrier layer consists essentially in the transition of the Charge from the electrically conductive layer into the photoconductor insulating layer to prevent such an unwanted discharge the photoconductor layer to prevent.

Disadvantages of the previously known electrophotographic recording materials is that it is difficult to achieve good adhesion between the electrically conductive layer and the barrier layer or between the photoconductor insulating layer and the barrier layer «.- ways the lack of good interlayer adhesion has failed many of the heretofore known electrophotographic elements practically not be bent without the layers attached different places separated from each other.

the invention

The task / is therefore to provide an "electrophotographic recording material that does not suffer from these disadvantages"

009844/1513

BATH

The invention therefore provides a elektrophotographiscfees recording material comprising a layer support a load applied to the substrate electrically conductive layer to the _# a. electrically conductive layer adjoining barrier layer and a photoconductive layer adjoining the barrier layer, which is characterized in that the barrier layer consists of polycarbonate resin or contains one which consists of repeating units deT general formula

C-O-

R.

is structured, in which mean:

(D

R- and R-

an optionally substituted phenylene radical and

individually each a hydrogen atom or a short-chain alkyl group with 1 to 6 iioh lens toff atoms or together with the carbon atom to which they are bonded, a mono- or polycyclic hydrocarbon residue.

In the formula given in deT, R can, for example, be a halogen-substituted phenylene radical, e.g. B. be a chlorophenylene / dibromophenylene or dichlorophenylene radical. R. and P ₂ can e.g. B. methyl, ethyl, propyl, isopropyl, butyl, l'entyl or hexyl radicals or, together with the carbon atom to which they are attached, a monocyclic hydrocarbon radical having 4 to 10 ring carbon atoms, e.g. B. a cyclobutyl or Cycle · hexyl radical or a polycyclic hydrocarbon radical, ζ. Β _{β is} a norbornyl residue.

- 3a -

009844/1513

Particularly valuable polycarbonates for the production of the locking = layers of the electrophotographic recording materials according to the invention are polymers made up of repeating units of the following general formula II.

H H

! i> - C C

H ₂ C CH ₂ O

wherein

^R 3 » ^R 4 * ^R 5 ^{and R} 6 each represent a hydrogen atom or a halogen atom and

and

individually one alkyl radical with 1 to 3 Carbon atoms mean or together with the carbon atom to which they are attached are, form a polycycloalkane radical.

Particularly suitable polymers are the poly (4,4'-isopropylidene-ß-diphenyl-tetrahydrofuran) and the poly ^(4,4-f -norbornyliden 2,2 ', 6,6'-tetrachlordiphenylcarbonat-ß-tetrahydrofuran).

0098AA / 15 13

BATH ORIGINAL

191522

The preparation of compounds of the type described is from the "Journal of Applied Polyaer Science", Vol. IX (1965), 3451, known.

The new barrier layers made from a diarylalkane fractions and polycarbonate resin containing tetrahydrofuran and between the photoconductive layer and the electrically conductive layer »can be produced in a known manner, for example by spray coating, Dip coating, fluid coating, coating all in one Extrusion hopper, drop application with a continuous feeder and the like.

The layer thickness can also be very different. Layer thicknesses of about 0.431 to about 5.38 g / a ² (0.04 to 0.50 g / ft.) Based on the dry weight of the resin have been achieved. Particularly advantageous layer thicknesses correspond to about 0.538 to. about 4.31 g / m ² (0.05 to 0.40 g / ft. ² ) polycarbonate resin.

A wide variety of conventional carrier materials can be used to produce the electrophotographic recording materials according to the invention, for example made of glass, wood, paper including coated paper, %% B. Kit polyethylene or polypropylene or baryta (BaO) etc., coated paper, polymeric substances, such as B. Cellulose acetate, poly (ethylene terephthalate), polyethylene and polypropylene.

The applied to the substrate ^, electrically conductive Layer can be made in different ways from different fabrics getting produced. A method sub applying such electrically conductive layers process steam at AISF as • s example d®t aiss US Pat Z $ 75 165 known · A eadares geelgsä ^ fts V®tf »HREA nut production of the electrically conductive! Sehielst © n consists in placing a LSsimg ® £ n »g @l <ikf? Is $ h conductive adar semiconductive on the layer support

0 0 9 8 4 4/1513

Material and a resinous binder in a volatile solvent and evaporating the solvent, leaving an electrically conductive layer. Such methods are known from US Pat. No. 3,245,833, for example.

Particularly advantageous electrically conductive layers that can be used in conjunction with the new separating layers can be made from metal-containing semiconductor compounds, e.g. B. from copper (I) iodide and silver iodide, for example by the method known from US Pat. No. 3,245,833. Conductor connections can electrically conducting layers of metal-containing half "of other such. B. according to the impregnation process described in the USA patent application old Serial Ne, 717 336. The semiconductor compounds containing metal can be used in various concentrations. Layer thicknesses corresponding to about 0.0431 to about 0.431 ag / m ² (4 to 40 ng / ft ² ), based on the dry weight of the semiconductor compound, are preferably used *

The photoconductive layer of the electrophotographic recording materials according to the invention can consist of the usual photoconductor layer. The photoconductors can consist of inorganic, organic and organometallic compounds. Suitable photo le it he are, z. B. zinc oxide, titanium oxide, organic derivatives of metals of group IVa and Va of the Periodic System of the Elements, for example those which contain at least one aeiseasyl = * group bound to the Met »11 * ta» group, arylamines and polyarylai class with asiad @ ste & s eimern Aainosubstituenten "organic photoconductivity", which are useful for the production of the inventive electrophotographic apfcic @ n on photographic materials, are "3, aas de®. Patent documents 3 139 331 »3 139 339, 3 140 §4§, S 141 3 141 982, 3 155 503, 3 257 Wt ₉ S 257 203 ₉ 3 257 204 3 265 49 €, 3 265 497 u & 4 I 174 000 known» Di®

after mixing »it eiaaa polymer®

medium £% ä £ ii® ^ rrecklcfet g

009844 / 1S13

-ir.

The photoconductor layer can be applied in various conventional ways e.g. by spray coating, fluidized coating, Coating with an extrusion funnel uww. The amount of photoconductor in the photoconductor layer can e.g. B. between about 10 to about 60 percent by weight based on the total solids in the photoconductive layer.

The electrophotographic recording materials according to the invention contain barrier layers which provide improved adhesion
and as a result adhere easily to adjacent layers.

The electrophotographic recording materials according to the invention can be charged positively or negatively electrically. They provide high quality copies with little Il background blackening.

example 1

A 0.0102 cm (4 mil.) Thick poly (ethylene terephthalate) film support was coated with a solution containing 0.4 g
a poly (vinyl formaldehyde) resin containing 5 to 7 liters of poly (vinyl alcohol) and 40 to 50 liters of poly (vinyl acetate), 0.4 g of one
75 % solids polyisocyanate crosslinking agent
with about 13 l isocyanate and 1% free tolould diisocyanate in
Ethyl acetate and 2.4 g of copper (I) iodide dissolved in 96.8 g of acetonitrile. This solution, which according to example 16 of the
U.S. Patent 3,245,833 was made from a
Extrusion funnel applied at a dry application rate of 0.129 g / m (12 mg / ft.) To form an electrically conductive layer.

The clear resin solution, which consisted of * g of poly (4,4'-isopropylidene-diphenyl carbonate-ß-tetrahydrofuran), dissolved in 38.8 g of dichloromethane and 58.2 g of 1,2-dichloroethane, was then applied in a dry amount of 1.078 g / m (0.1 g / ft. ² )

applied directly to the electrically conductive copper (I) iodide layer. The electrically conductive layer obtained thereby becomes
hereinafter referred to as composite layer A.

009844/1513

BATH

Another clear resin solution prepared from 9.8 g of cotton cellulose nitrate dissolved in 85.2 g of methyl alcohol, 2.3 g of n-butyl alcohol and 2.7 g of cyclohexanone was also obtained with the aid of . . an extruder in an amount, measured dry, of 2.05 g / m (0.19 g / ft) applied directly to a corresponding, electrically conductive copper (I) iodide layer. These two layers are referred to as composite layer B in the following.

Then a highly light-sensitive photoconductor layer, which according to the in the Belgian patent specification 705 118 (cf. also the corresponding French patent specification 1 547 628 and the German patent application P 15 97 827) described method was produced, with the aid of an extrusion funnel in

2 2

an amount of 15.09 g / m (1.4 g / ft) on the composite layer

A applied.

The coating composition for producing the photoconductor layer was produced from 9.0 g of a polycarbonate resin formed in the reaction of phosgene with a dihydroxydiarylalkane or in the transesterification between diphenyl carbonate and 2,2-bis-4-hydroxyphenylpropane; 6.0 g of 4,4'-diethylaraino-2.2 ^f -dimethyltriphenylraethane, 0.3 g of 4- (4-dimethylaminophenyl) -2,6-diphenylthiapyryliuraperchlorat in 51.0 g of methylene chloride and 34.0 g of 1.1, 2-trichloroethane. The solution was then stirred in an intensive mixer for a period of time and applied to the composite layer YES so that an aggregate about 0.2-0.4 microns in size was formed. The three-layer coating obtained is hereinafter referred to as recording material I (material according to the invention).

In the same way, the same photoconductor coating sheet was dried in an amount using an extruder measured, applied directly to composite layer B from 15.09 g / a (1.4 g / ft). The three-layer coating obtained in this way is referred to below as recording material II (comparison material).

009844/1513

BATH

Comparison of the photosensitivities of the two recording materials,

The electrophotographic photosensitivities of the recording materials were then determined as follows: The recording material was electrostatically charged under a corona discharge source until the surface tension measured with the electrometer probe reached a value of about 600 volts. Then, the charged material was purified by a stepped standard gray scale having a 3000 ° K-Wolfransiichtquelle exposed "The exposure results in a 'reducing the surface tension of the element"namely', starting from its initial potential Vq i at each step of gray scale to a slightly lower potential V, the exact value of which depends on the actual amount of exposure hitting the surface, measured in seconds 'candles.' The results of these brasses were then entered in a diagram in which for each level the surface tension V versus the logarithm of Exposure was applied. The actual positive or negative photosensitivity of the material can then be expressed in terms of the reciprocal of the exposure required to reduce surface tension on any fixed, arbitrarily selected word. Unless otherwise stated, under the effective positive or negative photosensitivity

4, give the numerical expression divided by 10 to reduce the surface charge voltage by 600 volts 500 volts (100 volt shoulder light sensitivity) or exposure required to 100 volts (100 volt basic light sensitivity) to understand in seconds meter kerxen. The positive and negative 100 volt shoulder and base light sensitivities are given in the following table I »

Comparison of quality he d copy n ichnungsmaterialJen the two elektrophotogra phical Aufze.

An electrical contact was attached to the electrically conductive layer of the recording material I. Then it turned to one

009844/1513

1 9 ι b 2 2 1

electrically conductive metal plate an image receiving sheet as it ^

for example in the patent (patent application -

is described, launched. The photoconductive material and that; Image receiving sheets were now with the opposite surfaces brought so close together that there was an air gap of about 20 microns between the two surfaces. The electric conductive metal plate was then attached to the earth side of a power source and the electrically conductive layer of the photoconductive Materials was connected to the high voltage side of the power source. The photoconductive one located above the image receiving element The material and the electrically conductive plate were placed under a photographic microfilm enlarger (such as is available from the Eastman Kodak Co, under the trade name Recordak MEB Enlarger is sold), which is a microfilm negative in the Filra window contained.

The following procedure was carried out on the image receiving sheet creates a latent electrostatic image:

A global voltage of -1500 volts with respect to earth was applied to the electrically conductive layer of the photoconductive recording material. One second after the electrical voltage was applied, the recording material was exposed for one second. The light intensity impinging on the photoconductor was 1.2 β 14 ifeterkerzen (3 foot candles). The applied voltage of -15U0 volts persisted during the exposure and was terminated 1/2 second after the exposure was completed. This was followed by a voltage reversal, so that after exposure a direct current voltage of +1200 volts relative to earth was applied to the recording material for one second. The recording material and the image receptor bearing the electrostatic image were then separated. The electrostatic image was developed by immersion in a _{positive polarity JaIt 1} liquid electrophotographic developer of the type known from U.S. Patent 2,907,674.

009844/1513

BATH ORIGINAL

-ve-

The proof received is a positive copy of the negative original, which has a dense (well exposed), sharp and black appearance, has a uniformly low background blackening

The same procedure was repeated using the comparative recording material II. The copy quality is given in Table I below.

Comparison of the adhesion of the layers in the two electrophotographic recording materials "

In the procedure described above, Elements I and II were used repeatedly. While the procedure is being carried out the materials were often handled and exposed to the solvents in the liquid developer composition. After this Treatment, the recording materials were carefully checked to see how well the different layers adhered to one another. The results of this investigation are as follows Table Ϊ given;

Table I.

Photoconductor recording

material

100 V- 100 V- adhesion Quality of the shoulder base copy ♦

photosensitivity- photosensitivity sensitivity '(♦) (-) (♦) (-)

8000 8000 3200 3500

excellent

II

8000 8000 2500 3500 weak

good image density low background blackening

low image density

high background blackening

♦ Average of 12 prints

0098AA / 1513

BATH ORIGINAL Example 2

A photoconductor coating with lower photosensitivity was prepared by adding 12.0 g of the polycarbonate resin of Example 1, 3.0 g of the amino-substituted triphenylethane of Example 1 and 0.075 g of the thiapyrylium perchlorate of Example 1 in 51.0 g of dichloromethane and 34.0 g of 1,1,2-trichloroethane solved. The solution was, as described in Example 1, stirred. Beiffi applying the solution to the composite layers A and B of the material described in Example 1, the aggregate size obtained was about 0.1 micron. The recording materials obtained would hereinafter be referred to as recording materials III or IV. These materials were then »! as in Example 1 described, tested. The results of this test are given in Table II below.

100 V- Table II liability Quality of Photolei Shoulder- 100 V- Copy ♦ ter- on - photosensitive Base- drawing opportunity photosensitive potential (♦) (-) opportunity material 5600 4000 (+) (-) out good image density III 800 800 drawing low sub (invent net basic blackening dungs
according to) 5600 4000 weak low image IV 800 800 dense high (Comparison) Underground blackening

Average of 12 prints.

00984A / 1 5 1 3

BATH ORIGINAL

Kb

Example 3

A clear resin solution of 3.0 g of poly (4,4'-norbornylidene-2,2'-ojo'-tetrachloroliphenyl carbonate-ß-tetrahydrofuran), dissolved in 38.8 g of dichloroethane and 52.2 g of 1,2-dichloroethane was used directly on an electrically conductive copper (I) iodide layer, which like was prepared described in Example 1, applied. The resulting composite layer was then made with that described in Example 1 organic photoconductor coating compound coated. The obtained three-layer recording material became referred to as recording material V and, as described in Example 1, tested. The results of this test are in the summarized below in Table III. The sensitivity to light, the adhesion properties and the quality of the copies were practically the same as with the recording material I. were achieved.

Table III

Photoconductor recording material

100 V shoulder light sensitivity

100 V base

light sensitivity C +) (-)

liability

Quality of copies *

(according to the invention)

8000 8000

2800 3500

Excellent image density shows little under- ground blackening

Average of 12 prints.

0098 Ά A / 1513

BATH

Claims (9)

19U22-1 claims 1. Electrophotographic recording material, consisting of a support, one applied to the support electrically conductive layer, a barrier layer adjacent to the electrically conductive layer and one to the Barrier layer adjacent photoconductive layer, thereby characterized in that the barrier layer consists of a polycarbonate resin consists or contains one which consists of repeating units of the general formula •O- O I ¹ -R 0 0 H Is If -c- I. I. c- ^R 2 --ο- C- —Ϊ -O- —R ~ is structured, in which mean: and an optionally substituted phenylene radical and individually each a hydrogen atom or a short- _Λ . chain alkyl group with 1 to ό carbon atoms or together with the carbon atom to which they are attached, a mono- or polycyclic hydrocarbon radical " 009844/1513 IS 2) Electrophotographic recording material according to claim 1, characterized in that the polycarbonate of the barrier layer from repeating units of the general formula ° / H ^{"| 1/4} ^ i ϊ? 0 — CO / ^X ) -C— ^ Vo- CO C --C - HC CH ₉ L \ / L X ₀ / (ID is structured, in which mean: R-, R-, R ₅ and R, each a hydrogen atom or a halogen atom and Around individually one alkyl radical each has 1 to 3 carbon atoms or together with the carbon atom to which they are attached, one Polycycloalkane residue. 3) Electrophotographic recording material according to claim 1, characterized in that the polycarbonate of the barrier layer consists of PolyiijA'-isopropylidene-diphenyl carbonate-ß-tetrahydrofuran) . 4) Electrophotographic recording material according to claim 1, characterized in that the polycarbonate of the barrier layer consists of poly (4,4'-norbornylidene-2,2 ·, 6,6'-tetrachlorodiphenylcarbonatß-tetrahydrofuran ) . 0 098 A Ul 1513 5) electrophotographic recording material according to claim 2, characterized in that the electrically conductive layer consists of a metal-containing semiconductor compound and the photoconductive layer contains an organic photoconductor. 6) electrophotographic recording material according to claim S, characterized in that the metal-containing semiconductor compound of the electrically conductive layer made of copper (I) is iodide consists, 7) electrophotographic recording material according to claim 5, characterized in that the metal-containing semiconductor compound of the electrically conductive layer consists of silver iodide 8) Electrophotographic recording material according to Claim 6 or 7, characterized in that the barrier layer made of poly (4,4'-isopropylidene-diphenyl carbonate-ß-tetrahydrofuran) consists. 9) Electrophotographic recording material according to Claim 6 or 7, characterized in that the barrier layer consists of 'poly (4,4 * -norbornylidene-2,2 *, 6,6 ♦ -tetrachlorodiphenyl carbonate-tetrahydrofuran). 0098A4 / 1513 BATH ORIGINAL