| 摘要 |
PURPOSE:To securely detect the presence or absence of a paper by a single detector irrespective of the supplying passage through which the paper is supplied and even when the paper is set in a deviated position, by fixing the detector to a printing element or a carrier on which the printing element is mounted. CONSTITUTION:With the carrier 6 positioned at a home position, a home position switch 11 is turned ON, and 0 is set into a register A in a RAM. The carrier 6 is then moved rightward by a one-pulse amount at a time by a stepping motor 10, and 1 is successively added to the register A. The detector 12 is moved together with the carrier 6, and when it is opposed to the paper 3, it is turned ON to output a signal. The amount having been counted by the register A is the displacement of the carrier 6, that is, the distance X from the home position to the left side edge of the paper 3. Discrimination is made by answering the question M-2N>X?, where M is the entire moving range of the carrier 6 and N is left and right margin of the paper 3. When the answer is NO, an alarm is issued indicating the absence of the paper 3, whereas when the answer is YES, counting on the register A is stopped, and 0 is set into a register B. |
