c 0 0 mm c 1 8 mm x 0 5 mm and n 16 and selects the reciprocating creasing mode on a user 39 s display window of a digital creaser namely a parameter obtaining apparatus usually a control key and a display second a plurality of paper sheets are put into the digital creaser and a single chip microprocessor will control the stepping motor to drive the rubber roller set to transfer the first paper sheet to the creasing area third an optical sensor detects the paper sheet position the paper sheet sequence number i 1 is determined and the paper sheet sequence number i is stored temporarily in a storage fourth the single chip microprocessor according to the formula of creasing position p of reciprocating creasing calculates the creasing position p of the first paper sheet fifth the rubber roller set controlled by the single chip microprocessor rotates and transfers the first paper sheet to the creasing position p sixth the creasing die under the control of the single chip microprocessor makes a crease on the first paper sheet seventh the rubber roller set rotates and outputs the first paper sheet and transfers the second paper sheet into the creasing area this cycle continues when the 17th paper sheet is transferred in as 17 is larger than the total sheet number n n 16 the sequence number of the paper sheet will be reset as 1 by the detection module and stored in the memory with the continuous work of the creaser a plurality of sheets with different creasing positions will be output successively.