Abstract: The present invention provides a naphthoquinone derivative represented by the general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are as defined in the specification. An electrophotosensitive material containing this naphthoquinone derivative as an electron transferring material has high sensitivity.

Abstract: The present invention provides a naphthoquinone derivative represented by the general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are as defined in the specification. An electrophotosensitive material containing this naphthoquinone derivative as an electron transferring material has high sensitivity.

Abstract: In accordance with the present invention, there is provided a phenanthrylenediamine derivative represented by the general formula (1). The derivative is excellent in the electric charge transferring capability, the compatibility with a binding resin and the stability, thereby providing a photosensitive material which is highly sensitive and excellent in the durability. ##STR1## ?wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represent a halogen atom, an alkyl group, an alkoxy group or an aryl group; and a, b, c and d each represent an integer from 0 to 5!.

Abstract: The present invention provides a novel naphthylenediamine derivative which is superior in electric charge transferring capability, compatibility with binding resin and stability, and an electrophotosensitive material which has a higher sensitivity and an excellent durability. The above naphthylenediamine derivative is represented by the following general formula (1), and the electrophotosensitive material is formed by providing a photosensitive layer having this naphthylenediamine derivative as an electric charge transferring material on a conductive substrate. ##STR1## wherein R.sup.1 to R.sup.4, R.sup.5a to R.sup.5f and a to d are as defined.

Abstract: An image-forming machine including a photosensitive drum which is rotatably disposed and successively passes through a charging zone, a developing zone and a transfer zone; a charger for charging the peripheral surface of the photosensitive drum into a predetermined polarity; a developing device for developing an electrostatic latent image formed on the peripheral surface of the photosensitive drum into a toner image; a transfer means for transferring the toner image formed on the peripheral surface of the photosensitive drum onto a transfer paper; and a foreign matter-recovering means which is disposed between the transfer zone and the charging zone and comes into contact with the peripheral surface of the photosensitive drum, and removes foreign matter adhered onto the peripheral surface of the photosensitive drum, the foreign matter-recovering means having a foreign matter-recovering brush brought into contact with the peripheral surface of the photosensitive drum, an elastic holding member made of an elas

Abstract: The present invention provides a novel naphthylenediamine derivative which is superior in electric charge transferring capability, compatibility with binding resin and stability. The above naphthylenediamine derivative is represented by the following general formula (1) ##STR1## wherein R.sup.1 to R.sup.4, R.sup.5a to R.sup.5f and a to d are as defined.

Abstract: An image-forming apparatus employing a reversal developing system and using a photosensitive material capable of being charged into both positive and negative polarities and further using a transfer roller made of an electrically conducting sponge rubber. The photosensitive material and the transfer roller are press-contacted to each other with a suitable force, and a DC voltage is applied to the transfer roller, the DC voltage having a polarity opposite to the polarity of the potential created by the main charger and having a value larger than a charge start voltage of the photosensitive material but being so set that the potential on the surface of the photosensitive material after discharged is not larger than 50 V in an absolute value. This apparatus permits a toner image formed on the surface of the photosensitive material to be transferred at a high efficiency and enables the photosensitive material to be uniformly charged in a next cycle of forming image.

Abstract: The present invention relates to a benzidine derivative represented by the general formula (1): ##STR1## wherein R.sup.1 to R.sup.6, m and n are as defined in the present specification. The benzidine derivative improves durability and heat resistance of a membrane containing the same while maintaining high hole transferring capability. Therefore, an electrophotosensitive material, which comprises a photosensitive layer containing the benzidine derivative, has high sensitivity and is superior in durability and heat resistance.

Abstract: The present invention provides an electrophotosensitive material having an improved sensitivity in comparison with a conventional one, obtained by combining a trinitrofluorenoneimine derivative represented by the formula (1): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are the same or different and indicate a hydrogen atom, an alkyl group, an alkoxy group, an aryl group which may contain a substituent, an aralkyl group which may contain a substituent, or a halogen atom! as an electron transferring material with a prescribed electric charge generating material or hole transferring material.

Abstract: The present invention relates to a novel phenylenediamine derivative of the general formula (1): ##STR1## wherein R.sup.1 R.sup.2 R.sup.3 and R.sup.4 are selected from the group consisting of: alkyl groups, alkoxy groups, halogen atoms and aryl groups; and m, n, p and q are integers in the range of 0 to 3, andan electrophotosensitive material using the same as an electric charge transferring material.The phenylenediamine derivative is excellent in not only compatibility with binding resin but also electric charge transferring capability, particularly hole transferring capability. Therefore, a photosensitive material using the above derivative as an electric charge transferring material exhibits a higher sensitivity.

Abstract: An electrophotographic photoconductor includes: a conductive substrate and a photosensitive layer formed on the conductive substrate, wherein the photosensitive layer includes charge generating particles, a charge transporting material, and a binder resin, and the charge generating particles are made of a composition including a charge generating material dispersed in a binding medium.

Abstract: Disclosed is an organic photosensitive material for electrophotography which is characterized by containing a specific diphenoquinone derivative in an organic photosensitive layer of the material. The diphenoquinone derivative is a compound represented by the following general formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are alkyl groups, alkoxy groups, aryl groups or aralkyl groups, and at least one of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is an aryl group or an aralkyl group, and at least 2 of the remaining R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are alkyl groups or alkoxy groups,the organic photosensitive material mentioned above has excellent sensitivity and residual potential.

Abstract: An electrophotographic organic photosensitive layer is formed by using a diphenoquinone derivative A and a diphenoquinone derivative B having a larger absolute value for reduction potential as electron transport materials. The diphenoquinone derivative A is, for example, 3,5-dimethyl-3',5'-di-t-butyl-4,4'-diphenoquinone. The diphenoquinone derivative B is, for example, 3,3',5,5'-tetra-t-butyl-4,4'-diphenoquinone. The diphenoquinone derivative B is included in the proportion of 3 to 50 wt % on the basis of the total weight of the electron transport materials (the diphenoquinone derivatives A and B).

Abstract: The organic photosensitive material for electrophotography in accordance with this invention is characterized in that a non-symmetrically substituted diphenoquinone derivative represented by the following formulae ##STR1## wherein each of R.sub.1 and R.sub.2 represents an alkyl or aryl group, R.sub.2 having larger carbon atoms than R.sub.1, is used as an electron transporting agent. This photosensitive material has a residual potential limited to a low level, and shows excellent sensitivity in both positive charging and negative charging.