| 摘要 |
<p>PURPOSE:To reduce a rejection rate caused by a read error, by feeding backward automatically an error sheet to the front of a read head, converting a slice level by deciding a variable densisty of mark information, and executing re-read. CONSTITUTION:In case information is an error, the tip of a sheet is detected by a detecting element 16, and thereafter, a carrier motor 12 connected to rollers 4, 5, 7, 9 and 14 is rotated backward. The backward fed sheet passes through a carrier path 8 and a mark reading head 6, and thereafter, is carried to the second hopper 13, a detecting element 15 rotates forward the carrier motor 12 again by the timing for detecting the tip of the sheet, and at a position of the roller 14, the sheet 2 is fed in the forward direction again. At the same time, a slice level of an amplifier of the mark reading head 6 is switched automatically to a low level [slice level (i)] or a high level [slice level (h)] in accordance with contents of an error (the number of data has decreased or increased), and when the re-read sheet 2 passes through the detecting element 16, the slice level of the amplifier of the mark reading head 6 is returned to the original state.</p> |
