SHEET

PURPOSE:To prevent the occurrence of duplication in printing by connecting dots in a 1st section so that elements arranged parabolically are connected with each other in a central part and separating dots in a 2nd section away from each other. CONSTITUTION:A background is assumed to be a 1st section using dots A, and a character is assumed to be a 2nd section using dots B. Both of them have almost the same area ratio. When the sheet including the sections is used as an original for an electrostatic copying machine and is copied on a 'light side', the dots in the 1st section become thinner as mark A-1 shows, and the dots in a 2nd section become much thinner as mark B-1 shows. The 1st section turns into a grey background, while the 2nd section turns into a lighter grey cut-out character. Under 'light condition' the sheet turns into a white cut-out character on the light grey background. When the sheet is copied on a 'dark side', the characters shown by marks A and B advance +1 stages, a dark grey character on the grey background appears. When the sheet is copied under 'darker condition', the characters shown by marks A and B advance +2 stages, a back character on the dark grey background appears. Thus, a character on the background appears at any density level with various densities, and the occurrence of duplication can be prevented because the dots are smaller than usual.