| 摘要 |
<p>Magnetic developer for positively charged images comprises particles of a finely divided magnetic material dispersed in a vinyl aromatic or acrylic polymer binder; 0.2-4.0wt.% (w.r.t. polymer) of an aliphatic carboxylic acid with at least 14C and 0.5-5.0wt.% (w.r.t. polymer) of an alcohol-soluble metalliferous dye as negative charge control agent. The amt. of binder present is 45-95% of the amt. of magnetic material and the magnetic material has a non-compacted density of at least 0.42 g/ml, a max. ave. particle size (measured by electron microscope) of 0.35 micrometres and a ratio of max. dimension to min. dimension of 1.0-5.5. The developer allows development of positively charged electrostatic images and transfer of the image to a plain paper support with a high yield and without background contamination or enlargement of the contours of the image.</p> |
