DEVELOPING SHEET FOR CARBONLESS COPY PAPER

PURPOSE:To provide a developing sheet excellent in color forming properties and reduced in the contamination due to the transfer of desensitizing ink by using an org. developer as an electron acceptive developer and using carbon dioxide specified in a BET specific surface area, the ratio of the BET specific surface area and an average particle size, oil absorption and water absorption as pigment. CONSTITUTION:In a developing sheet for carbonless copy paper formed by providing a developer layer containing an electron acceptive org. developer, an adhesive and pigment as main components, calcium carbonate characterized by that a BET specific surface area is 25-55m/g, the ratio of BET specific surface area (m /g)/average particle size (mum) is 5-110, oil absorption according to an Ogura method is 120ml/100g or more and water absorption is 1.8g/g or more is used as the pigment. Calcium carbonate is used in an amount of 5-100%, pref., 10-60% by wt. of the pigment solid of the developer layer. When the amount of calcium carbonate is below 5wt.%, effect is not substantially obtained. Since calcium carbonate has high water absorbability, it is pref. to use calcium carbonate in an amount of 60% or less by wt. of pigment in the case of the use in a high solid coating solution.