JPH0636100B2 - Photoconductive assembly and method of making a toner image copy - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to photoconductive assemblies capable of transferring a developed toner image to a receiver.

Photographic microfilms, i.e. microfilms which use silver halide for imaging, can provide resolutions in the range of about 200 to 400 line sets / mm. Although this degree of resolution is acceptable, microfiche made from photographic microfilms cannot be renewed, i.e., they cannot add additional images the day after development, because the development system can This is because the photosensitivity is destroyed.

The refurbishable microfiche includes a photoconductive sheet onto which the microimage is toner developed by electrostatic means. These photoconductive sheets suffer from two major defects: (1) they generally have a colored background, which results in poor contrast; (2) over time, the properties of the photoconductive sheet. Changes and becomes more non-receptive when newer.

Therefore, it would be desirable to transfer a microimage from a photoconductive sheet developed thereon by an electrostatic method to an inert microfiber which provides good contrast and does not deteriorate over time, In that way, the microfiche will be able to be renewed after a long time, for example even years later.

As is well known in the art, the basic electrostatic process is to place a uniform electrostatic charge on the photoconductive insulating layer and imagewise expose it to disperse the charge on the exposed areas of the layer, and Developing the resulting electrostatic latent image with a substance known as toner. Toner is normally attracted to those areas that carry a charge, thereby forming a toner image corresponding to an electrostatic latent image. The toner image can then be transferred to a support surface such as a polymer film. The toner can be a powder material containing a blend of polymer and carbon or a liquid material containing an insulating liquid vehicle having finely divided solid material dispersed therein. The toner-development microimage is preferably produced by a liquid toner developer rather than a powdered toner developer, which means that the liquid toner developer has a better gradation than the powdered toner developer and has a higher resolution. This is because it is possible to give an image that has been imaged.

However, a problem caused by the use of liquid toner developers is poor transfer from the photoconductor to the receiver, especially when the transfer is achieved by heat, pressure, or a combination of heat and pressure. Is. In order to improve gray scale compatibility it is desirable to use a combination of heat and pressure to achieve the transfer. Poor transfer is evidenced by (a) low transfer efficiency, eg 50% or less, and (b) low image analysis, eg about 80 line sets / mm or less. Low transfer efficiency is bright and / or speckled. Low image analysis blurs the edges.

At present, the efficiency of toner transfer is at a high level after any standard liquid development when the transfer is accomplished by means of heat or pressure, eg about 5 without substantial loss of resolution.
It is generally not possible to raise it above 0%. Moreover, the level of analysis is generally limited to levels up to 80 line sets / mm.

SUMMARY OF THE INVENTION The present invention comprises a conductive support, a photoconductive layer and from about 5 to about 10.
It comprises a photoconductive assembly comprising a topcoat of a cured film-forming silicone polymer having a dry thickness of up to 0 nm (preferably 12.5 to 70 nm). By adjusting the thickness of the silicone topcoat on the photoconductive assembly within this range, a resolution of more than 80 line pairs / mm and often more than 200 line pairs / mm can be obtained.
It has been found that up to% image transfer can be provided.
The melting point of the cured silicone polymer must be high enough so that the silicone polymer does not liquefy during imaging or image transfer. Liquefaction during imaging or transfer produces hazy images. The present invention also provides such an optoelectronic assembly electrographically.
Sensitized, developed with a liquid toner developer, and transferred substantially all the toner image to the receiver surface while still having high resolving power.
The photoconductive collectors and methods of the present invention can be used to provide microimages on a microfiber by means of electrostatic methods.

DESCRIPTION OF THE FIGURES FIG. 1 depicts an enlarged cross-sectional view of one embodiment of the photoconductive assembly of the present invention.

FIG. 2 is a typical graph of the optical density of toner remaining in the photoconductive assembly as a function of silicone topcoat after the transfer process has been accomplished.

DETAILED DESCRIPTION OF THE INVENTION The photoconductive assembly shown in FIG. 1 is a conductive support 1.
1, photoconductive layer 12, and film-forming silicone
It includes a topcoat 13 made of a polymer.

Conductive support pairs 11 for photoconductive systems are well known in the art and can be of two general types: (a) a self-supporting layer or block of conductive metal or other highly conductive material; ) Polymer sheets, glass, to which a thin conductive coating has been applied, e.g. evaporated aluminum
Or an insulating material such as paper.

Photoconductive layer 12 can be either (A) an organic photoconductor or (B) a dispersion of inorganic photoconductor in the form of particles dispersed in a suitable binder. The thickness of the photoconductive layer depends on the material used, but is typically from 5 to 150 micrometers. The organic photoconductive layer comprises a charge generating layer containing one material such as a dye or pigment, and other materials such as a derivative of poly-N-vinylcarbazole or bis- (benzocarbazole) phenylmethane in a suitable binder. And a charge transport layer containing A two-layer photoconductor suitable for the present invention is described in US Pat.
No. 361,637. Alternatively, the organic photoconductor, as described in U.S. Pat. No. 4,361,637, can include only a single layer containing both charge generating and charge transporting materials.

Phthalocyanine pigments and poly-N-vinylcarbazoles with or without binders and their special sensitivity sensitizing additives are well known in the art.
For example, U.S. Pat. No. 3,877,935 describes the use of polycyclic quinone pigments in binders as photoconductive layers. U.S. Pat. No. 3,824,099 demonstrates the use of methine squarate and tri-arylpyrazoline compounds as electrophotographic charge transport layers. The use of poly-N-vinylcarbazole as a photoconductive insulating layer is disclosed in US Pat. No. 3,037,861. Many diverse organic photoconductors, such as quinones and anthlones, followed the development of carbazole-class photoconductors [eg,
Hayashi et al., Britain Chemical Society. Japan (Bull. Chem. Soc. Japan), Volume 39, (196
6), pp. 1670-1673], but carbazoles are still commonly used as photoconductors.

Inorganic photoconductors such as zinc oxide, titanium dioxide, cadmium sulfide, and antimony sulfide dispersed in an insulating binder are well known in the art and may be prepared by any of their conventional types. Can be used with sensitization charges. The binder can be selected from any that do not already contain a silicone material. Preferred binders are resinous materials including but not limited to styrene butadiene copolymers, modified acrylic polymers, vinyl acetate polymers, styrene-alkyd resins, Sawyer alkyl resins, polyvinyl chloride, polyvinylidene chloride, acrylonitrile, polycarbonates, polyacrylics. And methacrylic ester, polystyrene, polyester, and combinations thereof.

The material for the topcoat 13 can be selected from the family of film-forming silicone polymers, which can be further crosslinked by the curing action. A preferred class of these silicone polymers has the structure of the general formula: (In the formula, R ¹ , R ² , and R ³ are independently hydrogen, hydrosil group, alkyl group, substituted alkyl group, cycloalkyl group,
Selected from the group consisting of an aralkyl group, an aryl group, and an alkenyl group, and R ⁴ , R ⁵ and R ⁶ are independently selected from the group consisting of an alkyl group, a substituted alkyl group, an aryl group, an alkenyl group and an epoxy group. , N and m are positive integers or 0 such that n + m is in the range of about 50 to about 15,000).

What if R¹, R^Two, R^Three, R^Four, R⁵, Or R⁶Is
From about 1 when it is a alkyl or substituted alkyl group.
Up to about 20 carbon atoms, and preferably about 1 to about
It can contain up to 10 carbon atoms, eg methyl
Ru, ethyl, propyl, butyl, isobutyl, n-butyl
Le, pentyl, isopentyl, hexyl, heptyl, o
Cutyl, decyl, pentadecyl, eicosyl, and
It is similar to this. What if R¹, R^Two, R^Three,
R^Four, R⁵, Or R⁶Is a cycloalkyl group
, It is like cyclopentyl, cyclohexyl
Preferably from 5 to about 8 carbon atoms in the ring
Preferably containing from 5 to 6 carbon atoms in the ring.
What if R¹, R^Two, R^Three, R^Four, R⁵, Or R⁶Is
When it is a aralkyl group, it is benzyl or ethylphenyl.
, It is preferably more than 20 in total
Including some carbon atoms. What if R¹, R^Two, R^Three, R^Four, R
⁵, Or R⁶Is an alkenyl group, ethenyl,
Propenyl, butenyl, pentenyl, hexenyl, hep
Tenyl, octenyl, decenyl, pendadecenyl, ray
Like cosenyl, and the like, it has 2
To about 24, and preferably 2 to about 10.
Can include carbon atoms at. Aryl group is phenyl
Of le, naphthyl, anthril, and the like
Such as containing from about 6 to about 20 carbon atoms
Is not limited to. The above alkyl groups are not limited to chloride
Halogens such as compounds, bromides, fluorides, and iodides;
Alkyl as defined herein, and the like
Can contain a variety of different substituents including
It What if R^Four, R⁵, Or R⁶Is an epoxy group
In some cases it is up to 20 carbon atoms, and preferred
It can contain up to 10 carbon atoms. The present invention
The most preferred silicone polymer for carrying out
R^Four, R⁵, And R⁶But -CH₃Is what is. Starting
A particularly useful silicone polymer for clarity is R¹But -O
H and R^Two, R^Three, R^Four, R⁵, R⁶But -CH₃And
And n + m ranges from about 2000 to about 5000
It is an enclosure. Silicone poly suitable for the present invention
Marr in US Pat. Nos. 3,061,567 and 4,21.
6,252, which are referenced together.
Write here. Commercially available silicone polymers suitable for the present invention
Available from Dow Corning Corporation
Sill-off 23, sill-off 292, and Sill-
off 294, and General Electric
Includes SS-4310 available from Company.

Cross-linking of these polymers by methods well known in the art provides resinous materials that decompose without melting at high melting points, i.e. above about 100 ° C, or at elevated temperatures. A review of these types of compounds can be found in W. Noll "Chemistry and Technology of Silicones", Academic Press, New York (Academic Press, Ne
w York (1968)). The resinous materials disclosed in Chapter 6, and especially in Section 6.2, are the most useful materials for the present invention.

These silicone polymers are xylene or hepta
Dissolved in an organic non-polar solvent such as
For example, make a solution of about 10% solids or less, and then
For example, wire wound rod, knife, extrusion, or gravure application
The surface of the photoconductive layer is formed by techniques well known in the art such as
Can be applied to faces. Before applying,
Life extender, cure accelerator, crosslinker, and catalyst
Additives such as can be added. These poly
A suitable additive that can be used with
Is well known. For curable silicone polymers
R¹, R^Two, R^Three, R^Four, R⁵Or R⁶As a replacement for
It has one or more hydroxyl groups. That's it
Such additives include, for example, Dow Corning Corporation.
Sill-off available from Yong (Syl-off ) 297 adhesion
Accelerator / pot life extender, which has the general formula:(R in the formula⁷IsOr a long-chain molecule having C = C end), Dauko
Earning C-4-2117 curing accelerator / crosslinking agent,
It has the general formulaObtained from Dow Corning Corporation, and
Dow Corning XY-176 catalyst, Dow Corning Co.
-Obtained from the following formula:Including those having. R¹, R^Two, R^Three, R^Four, R⁵Well
Or R⁶An alkene as one or more substituents on the group
For curable silicone polymers containing nyl groups
The following additives may be included, for example:
Expression:Obtained from Dow Corning Corporation
U Corning A cross-linking agent such as DC-1107, then
Expression:A curing inhibitor such as dimethyl maleate having
As described in US Pat. No. 3,775,452
Catalyst such as platinum siloxane complex.

The coating concentration of silicone polymer can be varied to provide the desired coating weight on the photoconductive layer. It is typically applied in the range of 0.01 to 5% by weight with a wire wound rod (eg, # 4 Mayer rod, giving a wet thickness of 9.1 micrometers). Typical curing conditions are 50 ° C
To a few minutes, preferably from 2 to 10 minutes at temperatures ranging from 1 to 150 ° C. Room temperature curing is also possible,
However, under these conditions the curing time is significantly longer, for example 24
It's time.

To ensure good transfer characteristics of images developed with liquid toner
Determines the thickness of the dried coating of silicone polymer.
It turned out to be qualitatively significant. Very thin layers are the worst
With a useful limit of about 5 nm, essentially complete transfer and
It is effective in providing image clarity that does not diminish. Thickness range
At the high end of the enclosure, values up to 150 nm are selected
Can be used according to the
Generally not useful. Figure 2 shows after transfer to receptor sheet
The optical density of the black toner remaining on the surface of the photoconductive assembly.
The typical relevance of the degree of silicone topcoat thickness
Shown as a function. In addition, in FIG. 2, the vertical axis represents light.
The optical density remaining on the conductive assembly.
y) represents the toner, the horizontal axis is 0, 1, 2 to 6
Is sill-off 23 (SYL-OFF 23)% by weight, and
The numbers 0, 50, 100-300 indicate the dry thickness (nm).
And curves A, C and E are for toner A, toner of Example 5
A toner C and a toner E are shown respectively. these
Each curve has a silicone layer thickness less than 100 nm
Value of 100nm or more and 5nm or less
With significant loss of transcription efficiency. Hardened
The melting point of the silicone polymer is also important. Photoconductive
The interfacial temperature between the assembly and the receptor surface is often during the transfer process
Is about 100 ° C. or higher. Silico
The polymer coating should not liquefy during the transfer process.
I wonder why those liquids produce a blurred, shrunken image
Because it will be. After all, cured silicone poly
The mer should have a melting point above about 100 ° C.

The photoconductive assembly of the present invention can be applied to applications having a wide range of conventional liquid toner developers that provide high image resolution and good tone, but it is often from the surface of the photoconductive assembly to the receiver. Suffers from significant difficulties in the transfer of images. Liquid toner developers are generally characterized as a mixture of toner particles, for example, electroscopic particles in an electrically insulating hydrophobic liquid carrier. The liquid toner developer can flow over the surface bearing the electrostatic image, or the image bearing surface can be dipped into a dish of liquid toner developer.
The toner developer can also be sprayed or rolled onto the surface bearing the electrostatic image. The particular method of applying the liquid toner developer to the image to be developed can vary. After toner development, the image is then e.g. evaporated, sprayed,
And / or dry by heating. When the proper toner particles are dispersed in a properly chosen liquid carrier, they obtain an electrophoretic charge of the proper polarity. More details regarding examples of various types of liquid toner developers are available by reference to the following publications: US Pat. No. 2,89.
9,355; 2,907,674; 3,053,68
8; 3,058,914; 3,076,722; and 3,135,695. Generally, liquid carriers have low dielectric constants, eg, less than about 3.0 and greater than about 10 ¹⁰ ohm · cm. It comprises a hydrocarbon or a mixture of different hydrocarbons. These liquid carriers and mixtures of liquid carriers can be exemplified by materials such as benzene, toluene, turpentine oil, carbon tetrachloride, mixed halogenated hydrocarbons, cyclopentane, cyclohexane, petroleum distillates, and mixtures thereof.

The toner particles incorporated in the liquid carrier are fine particles capable of bearing an electrostatic charge. For details of material selection for these particles, reference can be made to the above mentioned documents.
These toner particles include pigments or dyes, which are
For example, it can be made from a large variety of organic and inorganic materials such as talcum powder, aluminum gold powder, carbon powder, gum copal, gum sandarak, iron carbonyl and iron oxide, especially magnetic iron particles, dyes and color pigments. For maximum efficiency, it is desirable to use pigments where most of the particles get a positive or negative charge of one sign.
Shown in Table I below are a number of pigments that have a negative charge in the liquid carrier and a number of pigments that get a positive charge in the liquid carrier. Several pigments of each type are shown in Table I. The carrier whose charge was measured was cyclohexane.

The particle size of the toner particles is generally from about 0.1 to about 20.0.
Should be in the micrometer range. Toners with generally smaller particle sizes give better resolution to the resulting print. For example, if a continuous tone copy is to be developed with a liquid toner developer, it is desirable to use a fairly small particle size, on the order of about 1 micrometer or less, for maximum resolution. Toner particles can generally be incorporated with a carrier liquid by some type of milling step or a combination of blending and milling. Other additives, such as stabilizers, binders, and desiccants can also be included in the developer. Generally, the final developer composition can include from about 0.01 to about 20 wt% toner particles and from about 60 to 99 wt% carrier liquid.

Transfer from the photoconductive assembly to the receiver can be accomplished by either of two methods. It has been found that thermal transfer performed by contacting a preheated receiver with a photoconductive assembly developed with liquid toner provides excellent transfer and fixing. The device for achieving this type of transfer consists of an aluminum plate with a poster plate attached on one surface to ensure uniform pressure application during transfer. The photoconductive assembly is then placed face up on the poster board and attached with a pressure sensitive adhesive. Preheat the receiver with a heated hydraulic ram, which will bring the photoconductive assembly and the receiver to 500-3000 psi.
Can be contacted for 0.2-5 seconds. Typically, transcription experiments are 1000-2000 psi, 0.5-1.
It was carried out at a contact time of 0 seconds and an interface temperature of 85-95 ° C. (ie the temperature between the photoconductive assembly and the receiver during transfer).

The second method that can perform toner transfer and fixing is Flash /
It is pressure transfer. This method uses the same holder as for the photoconductive assembly used in the heating method, but without the poster board backing. A receiver machine consisting of a receiver placed on a thick glass plate and placed on an elastic pad thereon is connected to a hydraulic ram. Directly below the glass plate is a xenon flash unit unit. The transfer method involves combining the imaged photoconductive assembly and the receiver at 1000-2000 psi and then exposing the complex to a xenon flash for 0.001 seconds. The material is then separated. In either method, the silicone polymer is partially or wholly removed from the photoconductive assembly as a result of the transfer step.

A wide variety of sheet materials can be used as the receiver surface, such as, for example, fabrics, paper, glass, and various polymers. Special interest in high resolution is polyamide, polyvinyl chloride, polyvinyl acetate, acrylic, melamine,
Polyvinylidene chloride (PVDC) primed polyester materials such as polyester, polystyrene and polyester that are generally smooth and visually clear.

The photoconductive assemblies of the present invention are useful in high resolution electrostatic imaging methods. The resolution provided by the assemblies and methods of the present invention make them particularly useful in creating and recreating microfushes. Presently, refreshing microfibers is usually done by electrostatic methods on photoconductive supports, which have a tendency to deteriorate. The articles and methods of the present invention allow for the renewal of microfibers mounted on a support that is less susceptible to degradation than the photoconductive support.

The following non-limiting examples illustrate the invention.

Example 1 A coating solution was prepared by mixing the following ingredients in the amounts indicated.

40% by weight of bis- (N-ethyl-1,2-benzocar
Bazol-5-yl) phenylmethane and 60% by weight
Polyester binder (Buitel 207) mixture
Formulated from woven aluminized polyester support
# 14 micrometer wet thickness on photoconductive material
The coating was applied with a 6 Meyer rod.

The coating was cured at 107 ° C for 3 minutes to give a dry thickness of about 70 nm. The coated sample was then adapted to darkness for 24 hours, corona charged at 500V, exposed through a step tablet and developed with a liquid toner developer.

Liquid toner developers for developing electrostatic images were formulated in the amounts indicated from the following ingredients: The developing components were mixed according to the following procedure: The carbon black was weighed and added to a ball jar (2600 ml nominal volume, 18 cm id).

2. The remaining ingredients were weighed into a conventional container, preferably a glass beaker, and the mixture was heated with stirring on a hot plate until a brown solution was formed. A temperature of 110 ± 10 ° C. was sufficient to melt the polyethylene.

3. The solution from (2) is ambient temperature, preferably about 20 ° C.
Until cooled in an unobstructed area. When cooled,
The solid precipitated and the cold brown slurry so formed was added to the ball jar.

4. Seal the ball jar, and 120 hours 70-
Rotated at 75 rpm. The jar had a total load of 475 g of raw material in the proportions indicated above.

5. When kneading was complete, the jar was emptied and the contents were placed in a container of suitable volume to make the final toner concentrate.

6. The toner concentrate was diluted to make a liquid toner developer containing 1 part concentrate for 100 parts by volume carrier liquid (manufactured by Isopar G, Exxon Corp.).

The developed image was transferred to PVDC primed polyester by means of flash transfer. Optical density measurements on the photoconductive assembly and the receiver sheet showed 100% transfer of the image.

Example 2 This example demonstrates the use of epoxy siloxane as a coating for photoconductive assemblies. The same type of photoconductive assembly and the same coating conditions as in Example 1 were used. The following general formula: Two epoxy siloxanes with ## STR4 ## were used with an antimony-based catalyst in heptane solution at a concentration of 0.5% by weight. The two epoxy siloxanes are n,
One of the values of m is epoxy /
It has a siloxane ratio of 1/10, and the other has a molecular weight of 1.
They were different as indicated by an epoxy / siloxane ratio of 1/9 at 3,000.

The coating is cured at 93 ° C (200 ° F) for 2 minutes to give about 70n
A dry thickness of m was given. After exposure, development and transfer under the same conditions as Example 1, the optical density reading is 100.
% Image transfer.

Example 3 In this example, and in Examples 4, 5 and 6,
Three silicone formulations were compared. Silicone is a trademark
Yotsute sill-off 23, sill-off 292, and
Sill-off 294, they are all Dowkonin
Obtained as a product from Guco Corporation. That's it
This is a silanol-terminated dimethyl siloxane
The number average molecular weights were different. All these silicones
Within the scope of Formula I. Those for application by application
Manufacturing details are as follows: 30-40 wt% solids in xylene from Dow Corning.
Of the resulting silicone formulation with heptane
Diluted to 6 wt% solids. Sill-off Add 297 fixing
Agent / pot life extender (8 layers based on solid silicone material)
%) To each solution and thoroughly mix the resulting mixture.
Got together; Dow Corning C-4-2117 hardening acceleration
Agent (8% by weight based on silicone solids) to each solution
Then the resulting mixture was thoroughly mixed;
U Corning XY-176 catalyst (silicone solid
10% by weight (based on weight)) to each solution and the resulting mixing
The ingredients were mixed thoroughly. Dilute the resulting solution with heptane
Thus, each of the three release coating materials 3, 2, 1,
0.75, 0.50, 0.25, 0.10, 0.075
And used to make a 0.050 wt% solution. Occur
The solution had a pot life of less than 12 hours, so the solution
The photoconductive assembly sample was applied immediately after preparation. Photoconductive material
Materials are (1) terephthalic acid, ethylene glycol and 2,
2-bis (4-hydroxyethoxyphenyl) propane
A polyester binder derived from (2) bis (4-die
Cylamino-2-methylphenyl) phenyl methane
Charge transfer material and (3) in combination with photosensitizer (4)
Spectral sensitizing dyes that absorb at visible and red wavelengths
Was formulated from a mixture of Paint is with a # 4 Mayer stick
Applied, which has a wet coating thickness of 9 micrometers
It was The coating was then air cured at room temperature for 4 to 12 hours.
Allow or let coating dry for 10 minutes and then at 80 ° C.
Cured at (176 ° F) for 3 minutes.

The photoconductive assembly sample was exposed under the same conditions as in Example 1 and developed with liquid toner. Transfer of the developed image from the processed photoconductive assembly samples was accomplished by means of flash transfer on PVDC primed polyester at 2000 psi.

Two methods of measuring release coating effectiveness were used in the evaluation of photoconductive assemblies. In the first method, the optical density and resolution for a series of release coated photoconductive assembly samples were compared to values from untreated samples. Acceptable results were defined as non-decrease in D _max and resolution.
In the second method, the transfer efficiency during flash transfer was actually measured. More consistent and, by necessity, more meaningful results were obtained by measuring the optical density remaining on the photoconductive assembly sample instead of calculating the actual% transfer. The optical density remaining on the photoconductive assembly was less than that which the% transfer calculations depended upon and was dependent on the original optical density. An optical density of 0.00 represents perfect transfer of the image. The optical densities transferred in all cases ranged from 1.0 to 2.0 and the resolving power was 150 lp /
The range was from mm to 200 lp / mm.

The results derived from this example also show what in the transfer characteristics.
There are also significant differences such as the curing method of silicone polymer release coating
It is not caused by. Sill-off 23 silicone
 Two identical sets of polymer samples, one set in air
Cured at room temperature (20 ℃) for 1 hour, the other set is in air
Dry for 10 minutes and then at 80 ° C (176 ° F) for 3 minutes.
It was cured for a minute and compared.

The sample was exposed as in Example 1 and developed using Toner A as defined therein. The developed image is exposed to P at 2000 psi by means of flash transfer from the sample.
Transferred to VDC primed polyester. The results are shown below: For samples, the following were used, unless otherwise indicated, samples that were air cured at room temperature. All optical density results reported here are averages of 6 to 8 measurements on two different samples.

Release coating dry thickness is 9 micrometer wet coating thickness
And concentration by weight of release agent, i.e. cured silicone
 Estimated by calculation from polymer. For example 3.0
And 0.05% by weight are 270 nm and 4.5, respectively.
equal to nm. Generally silicone polymer topcoat
The thickness of is estimated from:In the formula, w = concentration by weight of silicone in coating solution t₁= Wet thickness of the coating film defined by the individual wire coating rods
Size (nm) t_s= Thickness of dried silicone layer (nm) d₁= Density of solvent used (g / cm³) D_s= Density of dried silicone layer (g / cm³Example 4 This example is a sil-off to transfer efficiency. 297 dark
Show the effect of degree. Sill-off 23 (3% by weight) and
Change amount sill-off Three solutions containing 297 were prepared.
Sill-off The amount of 297 is from 8 to 24% by weight (Silicone
Changed (on corn solids basis). Silicone polymer
A release layer was coated on the photoconductor and the image was from Example 1.
Developed with Toner A and PV as in Example 3
Transferred to polyester primed with DC. For each sample
The results are shown below.

The above results are fixer, sil-off The amount of 297 is PVDC
Compare the transfer efficiency of this toner to the undercoat polyester.
Indicates that there is no significant effect.

Example 5 This example shows the effect of different toner formulations. The test procedure was the same as in Example 2. The paint preparation method and test procedure were the same as in Example 3. The optical density was that of the toner remaining on the photoconductive assembly sample after transfer.

From the above results, all three release paints were used toners.
Improving the transfer properties of photoconductive assembly trials independently of
Will be taken care of. 0.25 to 1.0 paint
Solution containing up to wt% silicone polymer release agent
Produces optimal transcription when made from. MX-111
2 and optimal transfer for some toners such as toner E
Occurs over a wide range, but higher or higher
At low coating thickness a poor transfer tendency still remains. Three
For one liquid toner developer, toner A, C and E
The results are illustrated in Figure 2, where the photoconductivity after transfer is
Sil-off the optical density of the toner remaining on the assembly sample Two
Coating concentration of silicone polymer layer prepared from 3
And calculated dry thickness).

The following table shows toners B, C, D, tested in Example 5.
And the composition of E is shown.

Example 6 This example shows the quality of a toned image before transfer is achieved.
Silicone Polymer Release Agents, Sil, given to
-Off 23, sill-off 292, and sill-off
The effect of 294 is specified. Performed using liquid toner A
Exposure and development were carried out under the same conditions as in Example 1. Tested
The photoconductive assembly sample was the same as in Example 3.
Resulting from exposing a resolved bar diagram to a sample of photoconductive assembly
Maximum resolution line group in image with color tone / mm (lp / mm)
Resolution by visual reading with a weak force microscope.
It was measured. No exposure (D_max) And full exposure (D_min) To
The density with the corresponding color tone is measured by a Macbeth densitometer
did. A complete set of release agent coating thicknesses was applied as in Example 3.
Shoes The results are shown in Table X.

Thicker coatings of the release layer produced some loss in resolution, but no appreciable loss in the thinner layers. Moreover, there was a substantial increase in the D _max level without any deterioration in the transparency of the D _min area.

Example 7 This example illustrates a dry silicone for transfer efficiency and resolution.
The effect of the level of adhesion of the coating is demonstrated. Pair with photoconductor
In U.S. Pat. No. 3,554,836 for coating
Three silicone polymers showing the range of adhesive strength
I chose Photoconductor is bis- (benzocarbazole)
From phenylmethane (as disclosed in Example 1)
A 100 μm-thick film deposited with a thin opaque layer of minium.
Formulated on a conductive ester support. General
RTV 11, RTV 21, and RTV 6 according to Elektrik
Each of these silicones sold as 30 is 8
2,220 and 1220 g / cm²Has a viscosity value of
Was reported. Mix the following ingredients in the amounts indicated.
These silicone trichlorofluoromethane (Freo
The 11) The slurry in was prepared.

Slurries A, B and C are additional freons Nozomi by 11
To give 3, 1.0, 0.5, 0.25, 0.11 and
A continuous concentration solution with a concentration of 0.06% by weight was given. The solution is #
Apply to individual photoconductor samples using a 4 Meyer rod 9
Micrometer thickness was given. These coatings are air dried
It was dried and cured in air for 72 hours.

The samples were exposed, liquid developed in Toner E and flash transferred to PVDC primed polyester. A resolution of 100 lp / mm was typical in the transferred image.

Adhesion level results can be divided into 3 groups.

a) Samples showing photoconductor cracking, b) Samples showing partial transfer of toner c) Samples showing complete transfer of toner.

100% transfer could be achieved in all cases by using a sufficiently thick layer of cured silicone polymer. Silicones with high viscosity values were required to be applied in thicker layers to achieve comparable transfer levels. Therefore, in general, low tack silicones are preferred for the present invention because a thin layer of silicone is required for high resolution. Preferably, the viscosity value of the cured silicone polymer should be less than 300 g / cm ² .

Note that the thickest layer of silicone in this example is a dry thickness of about 0.5 micrometer, compared to a thickness in the range of 6 to 1500 micrometers in US Pat. No. 3,554,836. Should be.

Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of this invention, and the invention resides in the illustrative embodiments set forth herein. It should be understood that it should not be limited.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location G03G 15/20 107 (72) Inventor Evans, Jatquel United States 55133 Saint Poll, Minnesota, Pee. Oh. Box 33433 (72) Inventor Wilson, Robert Davrill United States 55133 Minnesota, St. Paul, Pea. Oh. Box 33433 (72) Inventor Paulson, Kenneth Earl, USA 55133 Minnesota, St. Paul, Pee. Oh. Box 33427 (56) Reference JP-A-55-25059 (JP, A) JP-A-57-72151 (JP, A) JP-A-57-155551 (JP, A)

Claims (12)

[Claims] 1. A conductive support, a layer of photoconductive material, and a cured silicone polymer having a dry thickness of about 12.5 to about 70 nm when cured and having a melting point of 100 ° C. or higher. A photoconductive assembly, including a topcoat. 2. The layer of photoconductive material comprises an organic photoconductor.
The assembly according to claim 1. 3. The organic photoconductor is poly-N-vinylcarbazole, -bis-benzocarbazole, methane, oxydiazole, phthalocyanine pigment, triarylmethane,
An assembly according to claim 2 selected from the group consisting of aromatic amines, hydrazones and pyrazolines. 4. The assembly of claim 1 wherein the layer of photoconductive material comprises an inorganic photoconductor dispersed in a binder. 5. The cured silicone polymer has the formula: (Wherein R ¹ , R ² , and R ³ are independently selected from the group consisting of hydrogen, a hydroxyl group, an alkyl group, a substituted alkyl group, a cycloalkyl group, an aralkyl group, an aryl group, and an alkenyl group, and R ⁴ , R ⁵ , R ⁶ are independently selected from the group consisting of alkyl groups, substituted alkyl groups, aryl groups, alkenyl groups and epoxy groups, and n and m are such that n + m is from 50 to 15,000. An assembly according to claim 1 formed by the cross-linking of a silicone polymer capable of forming a cross-link having a positive integer or 0). 6. The assembly according to claim 5, wherein the crosslinkable silicone polymer is silanol terminated dimethylsiloxane. 7. An assembly according to claim 5, wherein the crosslinkable silicone polymer is a vinyl functional polydimethylsiloxane. 8. An assembly according to claim 5 wherein the crosslinkable silicone polymer is a silanol terminated epoxy siloxane. 9. An assembly according to claim 1 wherein the cured silicone polymer layer has a viscosity value of less than 300 g / cm ² . 10. (1) a conductive support, a layer of a photoconductive material,
And a sensitized photoconductive assemblage comprising a topcoat composed of a cured silicone polymer having a dry thickness of about 12.5 to about 70 nm when cured and having a melting point of 100 ° C or higher. Steps of exposing to radiation to form (2) developing the assemblage exposed to form the image with liquid toner, and (3) heat / pressure transferring the toner-treated image to a receptor surface. A method of making a toner image copy. 11. The method of claim 10 wherein the transfer step is accomplished by flash / pressure transfer. 12. The method according to claim 11, wherein the transferred image exhibits a resolution of greater than 80 lp / mm.