Epson 4000 Service Manual - Page 148

EPSON Stylus Pro 4000 Revision B PAPER WIDTH DETECTION When paper is fed, the paper and platen are scanned and the change points of the detected reflective light levels (paper present level paper absent level) are confirmed as the paper edges. The diagrams below show scan/detection timing. At paper set At paper feed At printing complete 2nd job PAPER LEFT/RIGHT EDGE DETECTION DURING PRINTING This is performed during borderless printing. For borderless printing of the conventional printers, the data have been enlarged so that the data would run out of the left/right edges by 3mm in printing. This printer detects the paper edges with every pass, and by making immediate adjustments, the amount forced out is reduced to 1.1mm from the paper edge and the quantity of scattered ink is reduced. By executing every pass detection, printing can be performed while following skew of the paper when the paper has skewed (within the manufacturer's permitted range for skew), and the amount forced out is maintained at a fixed level. However, in order to prevent forcing out from absorption materials used for borderless printing, the printing is performed by maintaining a fixed quantity for one side. 1.1mm 1.1mm 1st job Absorption Material Figure 2-53. Paper Left/Right Edge Detection During Printing ASF Borderless Print ON ASF Borderless Print OFF Roll Paper Manual Insertion Borderless Print ON/OFF Figure 2-52. Paper Width Detection Timing Operating Principles Printer Mechanism Components 148