JPS58189645A - Electrophotographic photosensitive plate - Google Patents

Abstract

PURPOSE:To obtain the entitled photosensitive plate superior in electrophotographic characteristics, such as sensitivity or initial aceptance potential, by forming a photoconductive layer on a specified underlayer formed on a metallic aluminum layer vapor deposited onto a polyester film. CONSTITUTION:A metallic aluminum vapor deposition layer 3 is formed on at least one side of a 30-200mum thick biaxially stretched polyester film 2 made mainly of ethylene terephthalate units, the layer 3 is coated with a compsn. obtd. by mixing 25-75wt% TiO2 with a thermoplastic resin, such as polyamide having 8-17 amide groups per 100 C, having 10<6>-10<12>OMEGA.cm vol. resistivity at 20 deg.C 65% RH to form a 2-10mum thick underlayer 4. On this layer a 2-20mum thick photoconductive layer is formed consisting of an electron donative org. polymer photoconductor, an electron attractive polycyclic aromatic nitro compd., and phthalocyanine or its deriv.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive plate for electrophotography, and more particularly, the present invention relates to a photosensitive plate for electrophotography. The present invention relates to a photosensitive plate for electrophotography which effectively eliminates capri caused by capri and discharge breakdown during repeated charging, and which has improved electrophotographic properties and workability during manufacturing.

In commercial electrostatography using a two-component developer, that is, a developer consisting of a mixture of a magnetic carrier and a toner,
An electrostatic latent image is formed on an electrostatographic photosensitive substrate provided with a photoconductive layer by uniform charging and double-image exposure, and this photosensitive substrate is transferred between the two using a magnetic brush of the two-component developer. The electrostatic latent image is rubbed with toner while a bias voltage is applied to the photosensitive substrate, the toner image on the photosensitive substrate is transferred onto copy paper (transfer paper), and then the toner image is transferred onto the copy paper. A copy is formed by fixing. After the toner has been transferred, the photosensitive substrate is rubbed with a cleaning member such as a fur brush to remove residual toner, and is repeatedly used in the electrostatic photographic process described above.

As a conductive substrate, metal aluminum foil is economical and easily available, while as a photoconductive layer, a material in which a photoconductive substance is dispersed in an organic polymer binder is economical. Moreover, it is easy to manufacture, but when such a photosensitive plate is used, fog and pinhole-like white background defects will occur in the copies after a relatively small number of repeated uses, resulting in problems with the quality of the copies. The sharpness of the image and the life of the photosensitive plate are still unsatisfactory.

In a photosensitive substrate in which the conductive substrate is made of metallic aluminum and a binder made of an organic polymer is present in the photoconductive layer, the occurrence of such capri is caused by the formation of an amorphous magnetic carrier during repeated use of the photosensitive substrate. penetrates the conductive substrate through the photoconductive layer, which forms a conductive path from the magnetic brush to the conductive substrate when exposed by the magnetic brush, resulting in a bias-free pattern and a linear capri pattern. On the other hand, the pinhole-like blank areas are caused by the potential gradient between the metal aluminum and the photoconductive layer being too large, which causes discharge breakdown of the photoconductive layer during the charging process.

Conventionally, in order to prevent such white background omission, an under layer of resin having lower electrical resistance than the photoconductive layer resin was provided between the photoconductive layer and the aluminum foil. The resin has tack (
(adhesion) tendency, making it difficult to operate the winder, and when applying the photoconductive layer, the solvent seeped into the underlayer, making it difficult to apply the photoconductive layer. , problems such as a decrease in the initial saturation band potential occur.

Therefore, it is an object of the present invention to
To provide a photosensitive plate useful as a photosensitive master for electrophotography, which is free from fogging due to bias loss and blank areas due to discharge breakdown, has excellent electrophotographic characteristics such as sensitivity and initial charging potential, and has a relatively long life. It is in.

Another object of the present invention is to provide an underlayer that does not have the aforementioned tack tendency or seepage of the solvent of the coating composition for the photoconductive layer;
The object of the present invention is to provide a photosensitive master tube for electrophotography that is easy to manufacture.

According to the present invention, a vapor-deposited layer of metal aluminum is provided on at least one surface of a polyester mainly composed of ethylene terephthalate units, and a metal aluminum vapor-deposited layer is formed on the metal-deposited layer at a temperature of 106 to 10'2 Ω under the conditions of 20°C and 60°RH. - a thermoplastic resin having a volume resistivity of 25 to 7 per resin;
Provided is an electrophotographic photosensitive plate comprising an underlayer consisting of a thin layer of a composition containing 0% by weight of a titanium dioxide pigment, and a photoconductive layer provided through the underlayer. .

The invention will be explained in detail below with reference to the accompanying drawings.

In FIG. 1 showing the photosensitive plate of the present invention, this photosensitive master 1 includes a biaxially stretched polyester film 2 containing ethylene terephthalate units, and a metallic aluminum vapor-deposited layer 3 applied to at least one surface of this film 1. , an underlayer 4 provided on the metal vapor deposited layer, and a photoconductive photosensitive layer 5 provided via the underlayer.

The base film 2 is a polyethylene terephthalate film produced by biaxially stretching the film, i.e., in the longitudinal direction and in the transverse direction. It is characterized by having toughness, heat resistance, and dimensional stability, and its thickness is in the range of 30 to 200 microns, particularly 50 to 100 microns. The nine metal aluminum vapor deposited layer 3 applied on at least one surface is
It is formed by heating and evaporating metallic aluminum under high vacuum and condensing it on the film surface, and this vapor deposited layer is an extremely thin plating layer of 1 micron or less.
This is a remarkable feature.

That is, when this photosensitive plate 1 is used as a photosensitive master in electrophotography, as shown in FIG.
is removably attached to a grounded master support drum 6 using claws 7, the photosensitive layer surface 5 is uniformly charged with a charge of a constant polarity by a charger 8, and then an optical system 9 is attached.
through image exposure (7) to form an electrostatic image corresponding to the original image.

Next, the electrostatic image on the photosensitive master is brought into contact with a magnetic brush 10 of a two-component developer consisting of a magnetic carrier and toner to form a toner layer, followed by a transfer step 11 and a cleaning step 12 to complete one copying cycle. .

At this time, as mentioned above, the amorphous magnetic carrier contained in the developing magnetic brush penetrates the conductive substrate through the photosensitive layer, forming a conductive path from the magnetic brush to the substrate, resulting in bias failure and other problems. However, in the present invention, since the conductive layer of the substrate is a metal aluminum vapor deposited layer 3 with an extremely small thickness, even if the magnetic carrier pierces the photosensitive plate, the vapor deposition film at the pierced portion is immediately burned away. This provides the advantage that electrical insulation between the magnetic brush and the substrate is maintained, and fog due to bias failure is prevented. Furthermore, due to its excellent mechanical properties and dimensional stability, biaxially oriented polyester film can extend the service life of photosensitive masters, that is, the printing durability, by 50%.
It has the advantage that it can be increased to the order of 0 plates.

In the present invention, on this metal aluminum vapor deposited layer 2, a 1Q11Ω-
Thermoplastic resin with even volume resistivity and 2 per resin
An underlayer 4 is provided consisting of a thin layer of a composition containing 5 to 75 parts, in particular 4 to 50 parts, of titanium dioxide pigment.

First, by making the resin of this underlayer 4 have the above-mentioned resistance value, the sharp potential gradient between the photoconductive layer 5 and the metal vapor deposited film 3 is alleviated, and the light conduction during charging by the charger [15] Discharge breakdown is extremely effectively prevented. In the present invention, as the constituent resin of this underlayer, a polyamide resin, in particular, the number of a2do groups per 100 carbon atoms is 8.
It is preferred to use an amide resin in the range of 17 to 17, preferably 10 to 15. In other words, these amide resins not only have electrical resistance values within the above-mentioned range due to the presence of aodo groups in the polymer chain, but also exhibit excellent adhesion to metal-deposited films due to the presence of this amide repeating unit. Moreover, it has the advantage that this excellent adhesion is achieved without damaging the extremely thin metal deposited layer.

The present invention further provides the above-mentioned resin for forming a nine-under single layer,
By incorporating titanium dioxide pigments, the electrophotographic properties of this type of conductive substrate-underlayer-photoconductive layer type are significantly improved, and various workability in the production of photosensitive masters is also improved. It also has significant advantages. In other words, the titanium dioxide pigment blended into the resin for forming the underlayer prevents the tackiness of the underlayer and the solvent in the coating composition for forming the photoconductive layer is more effective than when other pigments are blended. It has a very unique effect of preventing seepage.

If the solvent seeps into the underlayer during the formation of the photoconductive layer, the saturation charging potential will drop significantly in the final charging process of the photosensitive plate, making it impossible to obtain a sufficient concentration, and the sensitivity will also drop significantly, causing further formation. It is inevitable that the original picture will become unclear. This is thought to be due to the underlayer constituent resin being mixed into the composition for forming the photoconductive layer. On the other hand, the titanium dioxide used in the present invention specifically acts to prevent the solvent from seeping into the underlayer, and other white pigments and fillers act to prevent such solvent seepage. This is something that cannot be achieved at all (see the comparative example described later). Furthermore, when applying the underlayer-constituting resin in the form of a solution to a metallic aluminum vapor-deposited film and then drying it, the titanium dioxide significantly prevents the coating from tacking. It becomes possible to perform coating and drying processes continuously while unwinding and supplying a roll of vapor-deposited film and winding up an underlayer coated film, thereby achieving significant advantages in terms of workability and efficiency.

As the titanium dioxide pigment, anatase pigment is excellent in terms of dispersibility in resin, but rutile type pigment can also be used. If the amount of titanium dioxide blended is less than the above range, it will be unsatisfactory in terms of preventing solvent seepage and tackiness. It is unsatisfactory in terms of points as well.

- The thickness of the under layer is desirably in the range of 2 to 10ξ microns, particularly 4 to 6 microns, from the viewpoint of preventing discharge damage and sensitivity of the photosensitive plate.

The photoconductive coating applied to this underlayer may be one in which at least the binder component is comprised of an organic polymer.

This organic polymer itself may have both the functions of a binder and a photoconductor, or an inorganic or organic photoconductor may be added to the organic polymer as a binder. It is useful as a photoconductive coating by dispersing it.

In the present invention, the organic polymer photoconductor may be any photoconductive polymer material known per se, such as poly-N-vinylcarbazole, poly-N-acrylphenothiazine, poly-N-(β- acryloxy-ethyl)-phenothiazine, poly-N, -(2-acryloxypropyl)-phenothiazine, poly-N-allylcarbazole, poly-N-'l-acryloxy-2-methyl-N-ethylcarbazole, poly- N-<2-p-vinylbenzoylethyl)-carbazole, poly-N-furobenylcarbazole, poly-N-'l-methylacrylic-oxapropylcarbazole, poly-N-acryliccarbazole, poly-4-vinyl-p -CM-carbazyl)toluene, poly(vinylanizalacetophenone), polyindene and other known photoconductive organic polymeric materials. Molecular photoconductors that are readily available and suitable for the purposes of the present invention are poly-N-vinylcarbazole and its nuclear substituted derivatives, such as halogen, alkyl substituted derivatives, and the like.

The above-mentioned organic polymeric photoconductors are electron-donating and can be used in the form of charge-transfer complexes in combination with electron-accepting compounds known per se, especially polycyclic aromatic nitro compounds. Such electron-accepting polycyclic aromatic nitro compounds include polycyclic aromatic compounds known per se that have at least one nuclear-substituted nitro group and are electron-accepting, such as 2
, 4-dinitro-1-/lornaphthalene, 1,4-dinitronaphthalene, 1,5-dinitronaphthalene, 5-nitro-N-butyl-carbazole, 4-ditrobiphenyl, 4,4'-dinitrobiphenyl.

1-chloro-4-nitro-anthraquinone, 2゜7-sinitro-anthraquinone, 2,4.7-trinitrofluorenone, 2,4,5.7-tetranitrofluorenone, 9-dicyanomethylene-2,4,7 -trinitrofluorenone, 4-nitro-acenaphthene, and the like. Polycyclic aromatic nitro compounds suitable for the purposes of the present invention are trinitro or tetranitrofluorenone.

The organic polymeric photoconductor and polycyclic aromatic nitro compound described above can be further combined with other inorganic or organic photoconductors to form a photoconductive coating. Suitable examples of such photoconductors include phthalocyanine or phthalocyanine derivatives,
Examples include perylene pigments, disazo pigments, trisazo pigments, and quinacridone pigments. Phthalocyanine or its derivatives that are easily available and particularly suitable for the purpose of the present invention are metal-free 7-thalocyanine and its nuclear-substituted derivatives, such as nuclear halogen-substituted derivatives. α01 to 148 mol per mol of constituent monomer of photoconductor, α15 to
to α45 mol of an electron-accepting polycyclic aromatic nitro compound, and Q per organic polymer photoconductor is 01 to 1
Preferably, the novel composition containing 0% by weight, especially 1% A2 to 4% I, of phthalocyanine or its derivative is used in a photoconductive coating, which photoconductive coating is combined with the above-mentioned underlayer metallized film. By using them in combination, it becomes possible to significantly improve the printing durability, that is, the repeated life of the photosensitive substrate.

As the organic polymeric binder which does not itself have photoconductivity and which constitutes the photoconductive coating, a thermoplastic or thermosetting resin known per se is used. The suitable front side is vinyl ester resin such as vinyl acetate resin; styrene resin such as polystyrene, styrene/butadiene copolymer; acrylic resin such as polyacrylate, polymethacrylate; vinyl chloride resin such as vinyl chloride/vinyl acetate copolymer. ; Vinyl acetal resin such as polyvinyl butyral; polycarbonate; epoxy resin, alkyd resin, phenol resin, amino resin, maleimide resin, etc., and one or a combination of two or more of these resins are used. Examples of the inorganic photoconductor used in combination with the agent include photoconductive zinc oxide, titanium dioxide, zinc sulfide, cadmium sulfide, zinc selenide, and the like. In addition to the above-mentioned organic photoconductors, polycyclic aromatic compounds such as naphthalene, anthracene, perylene, chrysene, anthraquinone, and violanthrone can be mentioned. It can be used in combination with sensitizing dyes known per se such as eosin, rosebencal, and tetraphthalmphenol blue.

In this latter photoconductive coating composition, the photoconductor tooth contains 920-700% by weight of an organic polymeric binder, and 0.5% by weight organic polymeric binder.
It is generally used in the form of a composition containing 0.01 to 200% by weight of sensitizer.

The photoconductive coating is generally applied over the oxide coating layer of the Al<Nira pentasubstrate to a thickness of 2 to 20 meters, particularly 4 to 10 meters.

Incidentally, instead of providing the above-mentioned single photosensitive layer as the photosensitive layer, a functionally separated multilayer photosensitive layer may be used. In this embodiment, a charge generation layer containing a photoconductive pigment is provided on the underlayer, and a charge transport layer containing a charge transport material is provided on the charge generation layer.

The excellent effects of the present invention will be explained with the following examples.

Experimental Example The following experiment was conducted to determine the content of titanium oxide.

A substrate was prepared in which 800 aluminum vapor-deposited layers were formed on one side of a polyethylene terephthalate film having a thickness of 75 μm.

Methoxymethylated boria-written resin (Teikoku Kagaku Sangyo KN, Torezin M-20,
Type II sorting 20% 1α8) f, metal/-ru 26. ,
Oxidized ff17 in Oyr, Q, 52) f (15% per resin), α54 town τ (25%), 1.08yr (5
0chi), 1.625'r (75chi), 1.94ir (9
0%) and each of the nine substances was mixed with an ultrasonic dispersion machine.
．． After dispersing for 2 minutes, an underlayer coating solution was prepared and coated with a wire so that the layer thickness after drying was 5 μm.

Table 1 shows the results of testing the adhesion to the substrate and the adhesion (blocking) of the underlayer after coating and drying (100° for 0.1 minute) for each of these underlayer coated substrates.

1 Table 4I-1 Peeling test with adhesive tape 04)-2100
After drying at ℃ for 1 minute, paper was stacked on the underlayer side and passed through a 400#/CX pressurizer to check the degree of adhesion between the paper and the underlayer.・Good △・・・Slightly good ×・・・Bad or better As the content of titanium oxide increases,
It can be seen that the cohesiveness of the under layer decreases.9. In addition, the results of the blocking test showed that blocking decreased as the content of titanium oxide increased.Next, to the base formulations 1 to 5 on which the underlayer was coated, a photosensitive layer of the following formulation was further applied. The coating solution was applied to the underlayer using a wire parser, and an image was produced on these photoreceptors at 80°C using an electrostatic photocopier (DC-15 manufactured by Sanda Kogyo Co., Ltd.). Regarding No. 1, white spots were observed due to discharge breakdown. In addition, regarding prescription 5, it was different from the one due to discharge destruction. In other words, the image was rough due to poor surface smoothness caused by too much pigment content in the underlayer.

Combining the above results, it was found that the content of titanium oxide is preferably 25 to 70% by weight per resin, considering image characteristics, coating work of the underlayer, workability, and binding properties of the underlayer. .

Example 1 As an under layer formulation, it was dispersed for 2 minutes using an ultrasonic dispersion machine, and coated on an aluminium-deposited polyethylene terephthalate film using a wire bar so that the thickness after drying was 5 μm.
The underlayer was dried at 00° C. for 2 minutes, and the zinc oxide photosensitive layer of the above-mentioned experimental example was further applied thereon.

This photoreceptor was used in an electrostatic photocopying machine (Sanda Kogyo Co., Ltd. DC-
15) and a printing durability test was conducted.

The results are shown in Table 2.

Comparative Experiment - 1゜Example 10 In the under-layer formulation, silica (Fuji Deguyson Chemical, K.) was substituted for titanium oxide.

An underlayer was provided in the same manner except that Thyroid P-244) was used, and a zinc oxide photosensitive layer similar to that in Example 1 was further provided thereon.

Using this photoreceptor, a printing durability test similar to that in Example 1 was conducted, and the results are shown in Table 2.

Comparative Experiment-2 Talc (Japan Talc f, f
Table 2 shows the results of a printing durability test conducted in the same manner except that MicroAce 1-1) manufactured by , Co., Ltd. was used.

As shown in Table 2, no decrease in image density was observed in the underlayer one using titanium oxide of the present invention, but other pigments such as silica and talc in Comparative Example-1 and Comparative Example-2 In the case of using the above, white spots occurred due to discharge breakdown and a decrease in image density was observed.

In addition, regarding the image quality of copies, those using titanium oxide can obtain uniform image quality through copying with a needle.
It was found that a uniform photosensitive surface was formed without penetration of the solution in the photosensitive layer. On the other hand, when using silica or talc, the overall image quality was rough, and a decrease in image quality was also observed during printing. This seems to be due to the formation of non-uniform image quality due to penetration of the solution into the photosensitive layer.

Example 2 An underlayer was formed in the same manner as in Example 1, and on top of that,
An organic semiconductor photosensitive layer having the following formulation was provided.

This photoreceptor was used in an electrostatic photocopying machine (DC manufactured by Sanda Kogyo Co., Ltd.).
-15) and formed an image, a good quality copy with no white spots was obtained. Furthermore, after 5,000 consecutive copies were made, the image quality was good, with no white spots and no roughness, just like the first copy.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the photosensitive plate of the present invention, and FIG. 2 is a copying process diagram in which the photosensitive plate of the present invention is used as a photosensitive master in electrophotography. Patent applicant Sanda Kogyo Co., Ltd.

Claims (2)

[Claims] (1) A vapor-deposited layer of metal aluminum is provided on at least one side of a polyester mainly composed of ethylene terephthalate units, and a layer of metal aluminum is deposited on the metal-deposited layer at a temperature of 20°C and 60% RH.
106 to 101 under these conditions! An underlayer consisting of a thin layer of a composition containing a thermoplastic resin having a volume resistivity of Ω-α and a titanium dioxide pigment of 25 to 70% by weight per resin is provided, and a photoconductive layer is formed through this underlayer. An electrophotographic photosensitive plate comprising: (2) The photosensitive plate according to claim 1, wherein the resin for forming the underlayer is a polyamide resin having 8 to 17 amide groups per 100 carbon atoms.