Patent ID: 6782814
Filing Date: 2004-08-31
Classification: B41F

Abstract:
A method for detecting registering errors for multi-color rotary presses which comprises steps ofprinting one or more register marks on a paper web in each printing section, causing a light source to flash based on a reference signal output by signal output means that operates in synchronism with the rotation of a predetermined reference plate cylinder and issues signals, causing reading means that operates in synchronism with the flashing of the light source to read the register marks printed by all the printing sections, developing the register marks into matrix data, and finding a first center of gravity from the matrix data as an approximate center of gravity of each register mark, using the first center of gravity as a basis point to find a second center of gravity as a high-precision center of gravity of each register mark, using the second center of gravity of a predetermined register mark as a reference to find the relative position of the second center of gravity of any other register mark, finding deviations of the found relative positions from a predetermined reference relative position, and regarding the deviation as a registering error.