Printing position correcting device

Abstract

Abstract PURPOSE:To print the printing information of a 2nd color without shifting the position, by changing the sending timing and carrying frequency of the printing information and the revolving frequency of a motor for driving a rotary polygon mirror in accordance with the degree of expansion and contraction of recording paper obtained by measuring the length of the recording paper before and after fixing. CONSTITUTION:Clock signals 10a are counted while a sensor output 10b, which becomes a high level during the period from the moment when a photosensor detects the leading edge of recording paper fed from a fixing device to the moment when the paper is passed, is outputted and a count signal 9a corresponding to the length of the counted fixed recording paper is sent to a main control section 3. The main control section 3 reads the count signal 9a from a counter 9 at prescribed timing and compares the count signal 9a with another count value corresponding to the length of the recording paper before passing through the fixing device so as to calculate the degree of expansion and contraction of the paper at the time of a 1st-color printing. Then the main control section 3 outputs voltage digital data 3d and 3e for aligning the printing information of the 2nd color to that of the 1st color to D/A converters 11 and 13 and the frequency of the carrying clock and the revolving frequency of a motor for scanning at the time of the 1st-color printing are changed.

Inventors

• 👤 Shigeru Ueda
• 👤 茂 上田

Bibliographic Details