| 摘要 |
<p>PURPOSE:To make the device smaller in size and lower at cost by disposing two pairs of roller pairs which revolve under pressure contact at a predetermined spacing and detecting the pressure changes by an image supporting body inserted between the rollers by means of piezoelectric rubbers, respectively. CONSTITUTION:The 1st and 2nd piezoelectric rubbers 15 and 15a which detect the pressure changes between rollers by the image supporting body inserted between rollers are provided to the roller pairs 4, 9 and 4a, 9a in feed and fixing roller units 1, 2. When the transfer paper is conveyed, the number of the pulses generated by a pulse generating circuit Q3 from the transmission of the output signal by the 1st piezoelectric rubber 15 until the transmission of the output signal by the 2nd piezoelectric rubber 15a is counted by a CPU. When no jam occurs, this count number is below the predetermined value, and the image forming process is continued. When the count number exceeds the predetermined value, an operation stop signal is outputted from the CPU, and a display lamp L is lighted. In this way, the small- sized and inexpensive device is obtained.</p> |
