Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Patent
1985-01-10
1986-10-14
Goodrow, John L.
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
G03G 506
Patent
active
046172475
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a photosensitive material for electrophotography, and more particularly to a photosensitive material having high sensitivity for electrophotography, which is capable of constituting a toner-applied surface causing no background coloring. Also, this invention relates to an electrophotographic photosensitive element having a layer of the aforesaid photosensitive material.
BACKGROUND ART
As photosensitive materials for electrophotography, many organic semiconductors have been investigated. In particular, polyvinylcarbazole (PVCz) has been widely used for electrophotographic photosensitive elements for the reasons that PVCz is imparted with a photoconductivity by irradiation of the near ultraviolet light, greatly increases the electric conductivity by exposure to light, easily forms a film, and gives a good surface smoothness in the case of forming a photosensitive layer or film. In such an application, for spectrally sensitizing PVCz to increase its photoconductivity due to the visible light to a practical sensitivity for electrophotography, sensitizing dyes such as triphenylmethane-based dyes, pyrylium-based dyes, cyanine dyes, etc., are added to PVCz.
However, when PVCz having the increased, visible light-induced photoconductivity by a spectral sensitization using conventional sensitizing dyes is used for a photoconductive layer, the following problems may occur.
(1) In the case of a direct type electrophotographic process, since the photoconductive material layer containing the sensitizing dye is colored by the light absorption of the dye to cause background coloring, it is necessary to reduce the amount of the sensitizing dye as low as possible (which causes the reduction of the sensitivity) or to decolor the dye by heat or light after the formation of images (in this case, incomplete decoloring or instabilization to heat or light is liable to occur and hence the restrictions on preserving conditions are increased); and
(2) In the case of successive application of yellow, Magenta, cyan and shadow toners onto one photosensitive plate in a color reproducing system, the sensitivity of the photoconductive material layer to light images to be exposed is reduced by the shielding effect (filter effect) of each toner, whereby it is difficult to obtain a constant exposure condition.
Also, since the conventional sensitizing dyes absorb the visible light, they have no sensitivity to the wave lengths of the infrared region; or in order that the photoconductive material layer has a sensitivity to the wave lengths in the infrared region, a large amount of the sensitizing dye must be used. Therefore, it is difficult to manufacture laser printers using an inexpensive and high illuminance light source such as a semiconductor laser.
SUMMARY
In a photosensitive composition for electrophotography comprising polyvinylcarbazole or a derivative thereof and a sensitizing dye, the compound of the following general formula is used as the sensitizing dye for being capable of constituting a toner-applied surface having a high sensitivity and having no background coloring; ##STR1## wherein Y represents S or ##STR2## Y' represents S or ##STR3## (wherein R.sub.2, R.sub.3, R.sub.2 ' and R.sub.3 ' each represents an alkyl group, said R.sub.2 and R.sub.3 together and R.sub.2 ' and R.sub.3 ' together may form a ring); Z and Z' represents a halogen atom, a nitro group, a cyano group, or an alkylsulfonyl group; R.sub.1 and R.sub.1 ' each represents a substituted or unsubstituted alkyl group; A represents --CH.dbd.CH--CH.dbd., ##STR4## (wherein D represents a halogen atom or ##STR5## wherein R.sub.4 and R.sub.5 each represents a substituted or unsubstituted alkyl or phenyl group); n.sub.1 and n.sub.2 each represents 0 or a natural number and n.sub.1 +n.sub.2 .gtoreq.2; and X.sup.- represents an anion.
An electrophotographic photosensitive element comprises a substrate, a conductive layer formed on one surface thereof and the photosensitive composition layer formed the conductive layer.
DISCLO
REFERENCES:
patent: 3619154 (1968-07-01), Cavagna et al.
patent: 3723116 (1973-03-01), Kinjo et al.
patent: 4435492 (1984-03-01), Suzuki et al.
Fukuma Toshiaki
Sato Tatsuru
Suzuki Kiyosuke
Goodrow John L.
Sony Corporation
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