DE2931279A1 - Electrophotographic photosensitive copying device - contains photoconductive insulating layer covered by protective light transmissive insulating layer - Google Patents

Abstract

Parent patent disclosed an electrophotographic photosensitive element for image transfer-type copying devices. The element comprises a photo-conductive, insulating layer obtd. by heat-hardening a dispersion applied to a conductive substrate and contg. fine photo-conductive CdS(Cu).nCdCO3(Cu) powder (where 0n =4), Mn stearate, thermosetting resin and solvent. Cu proportion is 0.025-0.1 atom % w.r.t. 100 atom % Cd and Mn stearate proportion is 2-4 pts. wt. w.r.t. 100 pts. wt. of powder. In this addn. novelty consists in covering the photo-conductive insulating layer with a light-transmissive insulating protective layer, pref. 0.2-2 mu thick. The protective layer may consist of a silicone-, acrylic-, melamine-, F-contg-, polyester-, urethane- and/or aminoplast resin. A very hard, smooth, abrasion-resistant surface is obtd. without impairing the photographic properties of the photo-sensitive layer. Damage on contact with developer or toner and/or cleansing devices is prevented.

Description

Electrophotographic,

light-sensitive element for copiers according to patent .....

(P 28 23 358.1) D e c h r e i b u n g The invention relates to a electrophotographic photosensitive member for image transfer type copiers; with a photoconductive insulating layer formed by thermosetting a a conductive base is formed of the applied dispersion, which is photoconductive fine powder of CdS (Cu) .nCdCO3 (Cu) where 0 <n c4-), nanganese stearate, thermosetting Contains resin and solvent, the copper content approximately 0.025 to 0.1 atom% to 100 atomic% of the Kadmiuis and the manganese stearate content about 2 to 4 parts by weight per 100 parts by weight of the powder.

The photosensitive element according to the main patent, which is preferably is used as a drum-shaped recording medium in copiers, draws particularly uniform high sensitivity in the entire spectral range, high charge, good Contrast and low image after-effects.

The object of the invention is to provide the photosensitive element according to of the main patent without impairing the functional properties mentioned to make mechanically more resistant.

This is achieved according to the invention in that the photoconductive insulating layer covered by a translucent insulating protective layer is, which is preferably a thickness of about 0.2 to 2 microns and advantageously from a synthetic resin such as silicone resin, acrylic resin, melamine resin, fluorine-containing resin, polyester resin, Amino resin or uretane resin or mixtures thereof.

This creates a very hard, smooth and abrasion-resistant surface of the photosensitive element achieved without the good properties of the underneath located photosensitive layer are lost. So that in particular avoid damaging or abrasion of the surface when in contact with developer or toner particles and / or with a cleaning device for Stripping off these particles comes about, especially when using an elastic one Scraper it can happen that toner particles are not stripped off, but are pressed into the drum surface and there a permanent film-like contamination form that into a visible Haze on copies. It has been found that this is practically complete with the present invention can be avoided.

The improvement according to the invention can be found in all of the main patent specified compositions of the photosensitive layer are used, and up. reference is made to the exemplary embodiments specified in the main patent.

An additional, particularly preferred embodiment of the present The invention is described in the following.

Example 5 According to example 3 of the main patent, a photo-sensor-height Element L with a photoconductive layer made of CdS.nCdCO3, the 0.05 Contained atomic percent copper and 3 parts by weight manganese stearate. liuf this became a insulating protective layer made of a thermosetting acrylic resin in the following manner educated. A thermosetting acrylic resin, as it is known under the trade name "Acryloid" sold by Ronm and Haas, is made with isopropyl alcohol in a weight ratio of 2s8 mixed and then applied to the photoconductive layer in such thickness, that the thickness after drying was about 1-2 pla. Then this coating Cured for 30 minutes at a temperature of 1200 C.

The photosensitive element with this insulating protective layer was tested in practical use, whereby it fetched Painting the cycle of charging, exposure, development with toner powder, image transfer on paper, removing the remaining toner and erasing the remaining charge became. An elastic cleaner was used as a cleaning device to remove the remaining toner Polyurethane scraper used, which has a sharp edge on the surface the protective layer. After 10,000 copies were made, the Element removed and examined for damage to the surface of the protective layer. No damage whatsoever could be found. There was also practically no Adhesion of toner observed, from which nan recognizes that the attachment of the insulating Protective layer effectively prevents the above-mentioned fogging.

Claims (3)

Electrophotographic photosensitive member for copiers according to patent (P 28 23 358.1) claims 1. Electrophotographic, light-sensitive. Element for photocopiers of the image transfer type, with a photoconductive insulating one Layer formed by thermosetting a conductive substrate Dispersion is formed, the photoconductive fine powder of CdS (Cu) .nCdCO3 (Cu) (where 0 <n # 4), contains nanganese stearate, thermosetting resin and solvent, the copper content being approximately 0.025 to 0.1 atomic percent per 100 atomic percent of the cadmium and the amount of nanganese stearate is approximately 2 to 4 parts by weight per 100 parts by weight of the powder, in that the photoconductive insulating layer covered by a translucent insulating protective layer is. 2. Photosensitive element according to claim 1, characterized g e k e n It should be noted that the protective layer has a thickness of approximately 0.2 to 2 μm. 3. Photosensitive element according to claim 1 or 2, characterized g e does not indicate that the protective layer is made of a synthetic resin such as silicone resin, Acrylic resin, melamine resin, fluororesin, polyester resin, amino resin, urethane resin or mixtures of which consists.