| 摘要 |
PURPOSE:To obtain a sharp image high in density without staining a roll with a toner by incorporating in a highly insulating hydrocarbon medium a specified copolymer insoluble in this medium, a specified copolymer soluble in it, a colorant, and an electrostic charge controller. CONSTITUTION:The liquid developer is composed of the highly insulating hydrocarbon medium, particles of a copolymer, insoluble in this medium, having copolymn. monomer units of vinyl acetate and additionally copolymerizable compd. having at least one ether bond or hydroxyl group in one molecule; particles of another copolymer, soluble in the medium, having copolymn. monomer units of an additionally polmerizable compd. having a carboxylic group; a colorant; and a charge controller. In this compsn., the copolymer soluble in the medium is dissolved and adsorbed to the dispersed resin particles of the insoluble copolymer, and improves their disparsion stability. Even when a running test is carried out as long as about one month by using such a liquid developer, no background stains are found on the image of a printing plate, and a squeezing roll can be kept clean. A toner having positive charge or negative charge can be optionally obtained by selecting a charge controller, a dye, etc. |
