Toner image degradation due to excessive buildup of thick deposits of a solid stable hydrophobic metal salt of a fatty acid on the surface of electrostatographic imaging members during successive imaging operations with development material containing the metal salt is prevented by continuously or intermittently maintaining the thickness of the buildup below about 10 microns by vigorous rubbing contact with a wiping member.
This application is a continuation-in-part of copending application Ser. No. 511,242, filed Dec. 2, 1965, now abandoned. This invention relates to imaging systems, and more particularly, to an improved development process .
An image forming apparatus of the present invention comprises an image carrier, a lubricant application device that applies a first lubricant to the image carrier surface, and a developing device that houses a developer to which a second lubricant is added and develops the electrostatic latent image formed on the image carrier. Here, the pure water contact angle .theta.1 of the first lubricant and the pure water contact angle .theta.2 of the second lubricant have the following relationship, .theta.1.ltoreq..theta.2. Furthermore, a frictional coefficient of the second lubricant may be larger than a frictional coefficient of the first lubricant.
In an electrophotographic reproduction process in which an electrostatic image is formed on a surface, developed with powder particles, the particle image transferred to a reception material and the surface re-used to form further images, the cleaning of the surface as with a brush or fibrous web before re-use of the surface is facilitated by applying to the surface at least one hydrophobic bivalent or trivalent metal salt of a half ester of a branched-chain or straight-chain aliphatic dicarboxylic acid or of a mono- or di-ester of a phophorus oxyacid. The metal salt can be deposited on the surface prior to formation of any image thereon or after transfer of the powder particle image.
An electrostatographic developing material comprising particles, said particles including finely divided electroscopic toner material and a minor proportion based on the weight of said toner material of at least one finely divided compound selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid, the metal and ammonium salts thereof; and a method of electrostatographic development employing said developing material.
A developer composition of the present invention contains a toner having at least a binder resin, a coloring agent and a toner scum preventive. The binder resin contains as a main component a polyester resin or a resin produced by concurrently carrying out addition polymerization and condensation polymerization in one reaction vessel. By using the toner of the present invention, since the formation of toner scum on the carrier surface can be prevented for a long period of time in the service life of the developer while retaining the low-temperature fixing ability of the toner, the carrier resistance and the triboelectric charge can be stably maintained, thereby providing a developer composition with a long service life. Accordingly, besides having a long service life mentioned above, the developer composition is highly suitably used for a high-speed semiconductive magnetic development.
A toner for developing electrostatic images is disclosed which comprises a coloring agent, a styrene homopolymer or copolymer with a vinyl monomer or monomers, and polypropylene in an amount between about 0.02 and 40 parts by weight per 100 parts by weight of the styrene homopolymer or copolymer.
