| 摘要 |
PURPOSE:To prevent occurrences of inferior image quality, drop of image density, and increase of a spent toner by using a specified styrene-acrylic copolymer as a fixing resin and specifying the size distribution of the toner. CONSTITUTION:The styrene-acrylic copolymer to be used as the fixing resin has in the gel permeation chromatogram for showing molecular weight distribu tion the maximum values above >=1X10<5> and within 5X10<2>-2X10<4> and the mini mum value between said maximum values, and a ratio of the sum of the areas of both peaks within them to the area of the valley below a line tying both peaks is <=0.30. In the particle diameter distribution of the copolymer particles measured with a coal tar counter, the volume base median diameter D50 is in the range of 7 - 13 mmu and a ratio of 25% remaining particle diameter to 75% remaining particle diameter is in the range of 1.3 - 1.7, thus permitting the obtained toner to prevent occurrences of inferior image quality, deterioration of image density, and increase of the spent toner. |
