| 摘要 |
PROBLEM TO BE SOLVED: To obtain an electrophotographic black liquid developer that makes an image having a high density of black color and excellent durability obtainable although the amt. of the toner deposited on a sheet is smaller than that of a dry developer, by using a specified azo pigment as a part of a coloring agent. SOLUTION: This liquid developer is prepared by dispersing a toner essentially comprising a coloring agent and a binder resin in a nonwater solvent having >=10<9>Ω.cm electric resistance and <=3.5 dielectric const. A part of the coloring agent consists of an azo pigment expressed by the formula. In the formula, R1 to R5 are each hydrogen atom, a halogen atoms, -OH-, -Cn H2n+1 or -OCn H2n+1 (n is an integer 1 to 4). The hue of the coloring agent in the liquid developer is not specified, however, black is preferable since the azo pigment expressed by the formula is red. Moreover, by incorporating a resin comprising fluorine-contg. monomers into the electrophotographic liquid developer, an image of good durability, excellent image density and no offset can be obtd.
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