JPH01170950A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To eliminate the need for repeatedly using an original at every copying by providing a recording layer which consists essentially of an org. low-polymer material dispersed in a resin base material and is reversibly changed in transparency by temp. CONSTITUTION:The recording layer 1 having a memory function is provided on one face of a base body 2. The recording layer 1 having the memory function has the reversible thermosensitivity and the characteristic that the transparency changes reversible with temp. Namely, said layer consists essentially of the resin base material, the org. low-polymer material dispersed in this resin base material and a material which is added thereto at need and controls the crystal growth of the above-mentioned org. low-polymer material. Direct copying on plan paper from a thermal head is thereby enabled. Copying is executable any times without the original after the original is once recorded on the recording layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and particularly to an electrophotographic photoreceptor provided with a recording layer having a memory function.

Since conventional electrophotographic photoreceptors do not have a memory function, the original had to be repeatedly exposed and charged each time it was copied. Therefore, there has been a demand for an electrophotographic photoreceptor equipped with a memory function.

An object of the present invention is to provide an electrophotographic photoreceptor provided with a recording layer having a memory function, which has not been seen heretofore.

Various commandments.

As a result of intensive research to achieve the above object, the inventors of the present invention have discovered that the main component is a resin base material and an organic low-molecular substance dispersed in the resin base material, and the transparency changes reversibly depending on the temperature. It has been found that the above object can be achieved by providing an electrophotographic photoreceptor characterized by being provided with a layer.

The present invention will be described in more detail below with reference to the accompanying drawings.

In the first embodiment of the present invention, as shown in FIG. 2, a recording layer 2 having a memory function is provided on one side of a substrate 2, a conductive layer 3 is provided on the opposite side of the substrate 2, and a conductive layer 3 is provided on the opposite side of the substrate 2. This is an electrophotographic photoreceptor in which a photosensitive layer 4 is provided on the conductive layer 3.

In another embodiment of the present invention, as shown in FIG. 3, a base body 2 provided with a recording layer 1 having a memory function and a base body 2 on which a conductive layer 3 and a photosensitive layer 4 are sequentially laminated are stacked. An electrophotographic photoreceptor made of

The recording layer 1 having a memory function, which is a characteristic component of the present invention, is reversibly thermosensitive and has a property that its transparency changes reversibly depending on the temperature. That is, in FIG. 1, the main components are a resin base material, an organic low-molecular substance dispersed in the resin base material, and a substance that controls the crystal growth of the organic low-molecular substance, which is added as necessary. The recording layer 1 having a memory function is, for example, in a cloudy, opaque state at room temperature below Tll. When this is heated to a temperature between T and T2, it becomes transparent, and even if it is returned to room temperature below T0 in this state, it remains transparent.

This is considered to be because the organic low-molecular substance passes through a semi-molten state and crystals grow from polycrystals to single crystals from the temperature T1 to T2 to below T0.

Further heating to a temperature of 13 or higher results in a translucent state intermediate between maximum transparency and maximum opacity.

Next, when this temperature is lowered, the liquid returns to its initial cloudy and opaque state without becoming transparent again. This is considered to be because polycrystals precipitate when the organic low-molecular substance is melted at a temperature T1 or higher and then cooled. In addition, after heating this opaque state to a temperature between T and T1, it is heated to room temperature,
That is, when cooled to a temperature below T0, it can assume a state between transparent and opaque. Also mentioned above.

Even if it becomes transparent at room temperature, if it is heated again to a temperature of 13 or above and returned to room temperature, it will return to its cloudy, opaque state. That is, it can take both opaque and transparent forms, as well as intermediate states, at room temperature.

Therefore, the entire recording layer 1 is heated by a heating means such as a heat roller.
After heating to a temperature between 1 and 12, a white image is formed on the recording layer 1 by cooling it to a room temperature below T0 to make it transparent, and then heating it in an image form with a thermal head etc. to make that part opaque. Ru.

On the other hand, after heating the entire partially transparent recording layer 1 to a temperature of 13 or higher, it is returned to room temperature below T0 to make the whole cloudy and opaque.
If the area is made transparent by heating to a temperature between 2 and 3, a transparent image will be formed with a white background. Note that the above-described image forming and erasing operations on the record M1 can be repeated 104 times or more.

Various solvents can be selected as the recording layer forming solvent depending on the resin base material and the type of organic low-molecular substance, such as tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, and chloroform.

Examples include carbon tetrachloride, ethanol, toluene, and benzene. Note that in the resulting heat-sensitive sheet, the organic low-molecular substance is precipitated as fine particles and exists in a dispersed state.

The resin base material used for the recording layer 1 is a material that forms a layer or film in which a low-molecular-weight organic substance is uniformly dispersed, and also influences the transparency at maximum transparency. Therefore, the base material is preferably a resin that has good transparency, is mechanically stable, and has good film-forming properties. Such resins include polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, and vinyl chloride acrylate copolymer. Vinylidene chloride copolymers such as polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer; polyester; polyamide; polyacrylate or polymethacrylate or acrylate Examples include tol methacrylate copolymer and silicone resin. These may be used alone or in combination of two or more.

On the other hand, organic low-molecular substances have a temperature T as shown in FIG. It may be selected as appropriate depending on the selection of ~T3, but the melting point is 30 ~ 2
00°C, particularly preferably about 50 to 150°C. Such organic low-molecular substances include alkanols; alkanediols; halogen alkanols or halogen alkanediols; alkylamines; alkanes; alkenes;
Alkynes; halogenalkanes; halogenalkenes; halogenalkynes; cycloalkanes; cycloalkenes; cycloalkynes; saturated or unsaturated mono- or dicarboxylic acids or their esters, amides, or ammonium salts; saturated or unsaturated halogenated fatty acids or their esters; Amides or ammonium salts; Allyl carboxylic acids or their esters, amides or ammonium salts; Halogen allyl carboxylic acids or their esters, amides or ammonium salts: Thioalcohols; Thiocarboxylic acids or their esters, amines or ammonium salts; Thioalcohols carboxylic acid esters and the like. These may be used alone or in a mixture of two or more. The number of carbon atoms in these compounds is preferably 10 to 60, preferably 10 to 38, particularly preferably 10 to 30. The alcohol group moiety in the ester may be saturated or unsaturated, and may be substituted with halogen. In any case, the organic low-molecular substance has at least one type of oxygen, nitrogen, sulfur, and halogen in its molecule, such as 10H1-C00.
H1-CONHl-C00R1-NH-1-NH,,-
Preferably, it is a compound containing 8-1-S-S-5-〇-, halogen, or the like.

More specifically, these compounds include lauric acid, dodecanoic acid, myristic acid, and pentadecanoic acid.

Higher fatty acids such as palmitic acid, stearic acid, behenic acid, nonadecanoic acid, arachidic acid, and oleic acid; higher fatty acids such as methyl stearate, tetradecyl stearate, octadecyl stearate, octadecyl laurate, tetradecyl palmitate, and tocosyl behenate. Ester; C1,)133-0-Cxs H33-CxGH3
3-3-Cx5'a3.

C1s H3? -5-Cx s H37, C engineering 2H□
-5-C1□H2,.

C1g%g-5-ClgHFs,”□H25-
Examples include ethers or thioethers such as 5-5-C1□H25°. Among these, in the present invention, higher fatty acids, particularly higher fatty acids having 16 or more carbon atoms such as palmitic acid, stearic acid, behenic acid, and lignoceric acid, are preferable, and those having 16 to 2 carbon atoms are preferable.
Higher fatty acids of No. 4 are more preferred.

The ratio of the organic low-molecular substance to the resin base material in the recording layer is preferably about 2:1 to 1:1s by weight, and 1:1 to 1:3.
is even more preferable. When the ratio of resin base material is less than this,
It becomes difficult to form a film that retains the organic low-molecular substance in the base material, and on the other hand, if the amount exceeds this range, it becomes difficult to make it opaque because the amount of the organic low-molecular substance is small.

The thickness of the recording layer is generally 1 to 30 μm, but whiteness can be increased by increasing the amount of fatty acid.

In addition, in the present invention, a substance that controls the crystal growth of the organic low-molecular substance can be used in combination, and this substance includes:
Examples include those that are eutectic with organic low-molecular substances and can widen the temperature range in which the organic low-molecular substances are in a semi-molten state, and those that promote crystal movement.

For example, those commonly used as surfactants include polyhydric alcohol higher fatty acid ester; polyhydric alcohol higher alkyl ether; polyhydric alcohol higher fatty acid ester, higher alcohol, higher alkyl phenol, higher fatty acid higher alkyl amine, higher fatty acid. Lower olefin oxide adducts of amide, oil g or polypropylene glycol; Acetylene glycol; Na, Ca, Ba or Mg salts of higher alkylbenzenesulfonic acids; Higher fatty acids, aromatic carboxylic acids, higher aliphatic sulfonic acids, aromatic sulfonic acids, Ca, Ba or Mg salt of sulfuric acid monoester or phosphoric acid mono- or di-ester; low sulfated oil; poly long chain alkyl acrylate; acrylic oligomer; poly long chain alkyl methacrylate; long chain alkyl methacrylate containing toluamine Monomer copolymers; examples include styrene-maleic anhydride copolymer niolefin to maleic anhydride co-wave type.

Also used as film plasticizers are tributyl phosphate, tri-2-ethylhexyl phosphate, triphenyl phosphate, tricresyl phosphate, butyl oleate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, Di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, dioctyldecyl phthalate, diisodecyl phthalate,
Butyl benzyl phthalate, dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, alkyl adipate 610, di-2 azelaate
-Ethylhexyl, dibutyl sebacate, di-2-ethylhexyl sebacate.

Examples include diethylene glycol dibenzoate, triethylene glycol di-2-ethylbutyralate, methyl acetyl ricinoleate, butyl acetyl ricinoleate, butylphthalyl butyl glycolate, and tributyl acetyl citrate.

In addition, one of the organic low-molecular substances listed above can be used as an organic low-molecular substance, and another type of organic low-molecular substance can be used as a substance that controls crystal growth. For example, stearic acid can be used as an organic low-molecular substance. Stearyl alcohol is used as a substance to control crystal growth.

The weight ratio of the organic low molecular weight substance and the substance that controls the crystal growth of the organic low molecular weight substance is preferably about 1:0.01 to 1:0.8. If the substance that controls the crystal growth of the organic low-molecular-weight substance is below this range, it will not be possible to widen the temperature range or energy range in which it becomes transparent, and if it is above this range, the opacity will decrease.

As shown in FIGS. 2 and 3, a recording layer 1 and a conductive layer 3 are provided before and after the substrate 2, and these layers must be optically transparent.

Examples of the substrate 2 include various transparent plastics (eg, polyester, polypropylene, polyimide, polyether sulfone, polyether ether ketone, acrylic resin, epoxy resin, polycarbonate, etc.), glass, and the like. The shapes of the substrate include films, sheets, belts, i-rams, etc. that can be used for electrophotographic photoreceptors.
A board etc. can be considered.

As the conductive layer 3, transparent aluminum, nickel,
Metals such as palladium, indium oxide (ITO),
Ni-based heat-resistant alloys (e.g. Hastelloy, Inconel,
(Mnemonic, Adimet, etc.) can be used.

The photosensitive layer 4 laminated on the conductive layer 3 includes an inorganic photosensitive layer (e.g., Se and Se-based alloy, CdS, ZnO, etc.), which is a conventionally known photosensitive layer, and an organic photosensitive layer (e.g., mainly composed of organic pigments). A layer formed by laminating a charge generation layer and a charge transport layer formed by dissolving an organic dye-based substance in a resin, etc.) can be used.

The manner in which the photoreceptor is manufactured and is equipped with a recording layer having a memory function will be described with reference to FIG.

First, in step A, the previously used image is erased from the recording M1 by thermal processing.

Next, in step B, the solid record M with the previously used image erased.
1, an image of the original is recorded by a thermal head 5 or the like.

In step C, the photosensitive layer 4 of the photosensitive member on which the image is recorded on the recording layer 1 is charged by the charger 6.

In step D, exposure is performed from the recording layer 4 side, and as a result, a charge remains only in the portions of the recording layer 4 corresponding to the opaque portions, and an electrostatic latent image is formed on the photosensitive layer 4.

In step E, the electrostatic latent image is developed using toner.

In step F, the developed toner image is transferred onto paper 8 and fixed.

In step G, the photoreceptor is cleaned.

The photoreceptor thus cleaned may then be returned to step C to repeat the copying cycle, or returned to step A to erase the image stored in the recording layer by thermal processing and create another new one. May be used for copying originals.

EXAMPLES Hereinafter, the present invention will be explained in more detail according to the following examples, but the present invention is not limited thereto.

Note that all parts used are parts by weight.

Example 1.

An alloy layer was formed on a 75 μm thick polyester film by sputtering using alloy Hastelloy B as a target so that the average light transmittance in the visible range was 30%.

(Left below) On top of that is a charge generation layer formed by dispersing a bisazo pigment represented by the following formula (1) in a butyral resin (raw material/resin, weight ratio 2.5/1).
was coated with a blade coating to a thickness of 0.3 μm, and on top of this, a charge transport layer (styryl compound/resin, weight ratio 9/10) formed by the following formula (II), which is compatible with the resin, was applied to a thickness of 20 μm with a blade coat.
m was applied.

Next, stearic acid is added to the back of this polyester film.
5 parts tetrahydrofuran
A solution consisting of 75 parts was applied with a wire bar and dried at 100 to 120° C. to form a dry layer with a thickness of 15 μm, thereby creating a cloudy, opaque recording layer as a whole, and completing a photoreceptor.

Next, as shown in FIG. 4, the recording layer was heated to 65° C. and then returned to room temperature to make it transparent (Step A).

A thermal head prints on the recording layer provided on the back of this photoreceptor (Step B), the photosensitive layer on the front side is charged (Step C), exposure is performed from the back side (Step D), development (Step E), and transfer. , fixing (process F), cleaning (process G), and charging (
Successive copies were obtained by repeating step C).

Further, the recording layer is reheated to 65° C., returned to room temperature, and made transparent again (step A), so that a copy can be made from the next new document.

Example 2 A photoconductor obtained in the same manner as in Example 1 except that behenic acid was used instead of stearic acid in the preparation of the recording layer was printed and copied using a thermal head, and clear images were continuously produced. obtained.

Example 3 When a photoconductor obtained by providing the same photosensitive layer and recording layer as in Example 1 on an aluminum vapor-deposited film (polyester film 75μ) with a transparency of 20% was printed and copied using a thermal head, clear images were continuously produced. Obtained.

Example 4 A solution consisting of 5 parts of stearic acid and 75 parts of tetrahydrofuran was applied to a polyester film (75μ) using a nozzle, and dried at 100-120'C to a film of 15μ.
A thick recording layer was formed.

A polyester film with a recording layer formed in this way,
A photoreceptor was completed by overlapping another polyester film with a conductive layer and a photosensitive layer provided in the same manner as in Example 1. Printing is performed on the recording layer of this photoreceptor using a thermal head, the photosensitive layer is charged, exposure is performed from the recording layer side, development, transfer, cleaning, and further charging is repeated to enable continuous copying or recording. layer at 65℃
It is also possible to make a new copy by heating the original to make it transparent again.

- As mentioned above, by providing a recording layer on a conventional photoreceptor, it is now possible to copy plain paper directly from a thermal head, and once an original is recorded on the recording layer, it can be copied without the original It is possible to make copies even once. It is also possible to edit images using the memory function of the recording layer.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the transparency of the recording layer and the temperature. FIGS. 2 and 3 are explanatory diagrams of the structure of the photoreceptor of the present invention. FIG. 4 is an explanatory diagram showing a usage pattern of the photoreceptor of the present invention. 1... Recording layer, 2... Support, 3...
- Conductive layer, 4... Photosensitive layer, 5... Thermal head, 6... Conductive layer, 7... Toner, 8... Paper. Figure 1 Figure 2, -4 Figure 3 ■ = Ishiguchi (A) CB) r =
I6 Transfer 3F, Image

Claims (1)

[Claims] 1. An electrophotographic photoreceptor comprising a resin base material and a recording layer whose main component is an organic low-molecular substance dispersed in the resin base material and whose transparency changes reversibly with temperature.