| 摘要 |
PURPOSE:To enhance the sharpness of an image and the whiteness of a recording sheet by forming a recording layer based on acid-treated activated clay having a specified aromatic adsorption index and a hydrophobic polymer on a support to rapidly attain high density coloration. CONSTITUTION:The refractive index of a mixed liq. of toluene and isooctane is changed when a dry sample is dipped in the liq., and the change is obtd. as an aromatic adsorption index from the refractive index difference of the supernatant liq. before and after adding the sample. Acid-treated activated clay having 20-40 aromatic adsorption index is used as a developer. This clay and a hydrophobic binder such as styrene-butadiene copolymer or acrylic resin are dispersed in a soln. to prepare a coating fluid, and this fluid is applied to base paper to obtain an electrostatic recording sheet. A latent image is formed on the sheet and developed with toner to rapidly give a high density image causing very little bleeding. Using the hydrophobic binder the active site of the activated clay is made polar, and the activity and insulating properties are not lowered. |
