摘要 |
Apparatus and metyod for making a gatefold in a central portion of a sheet along a gatefold line. The apparatus includes a fold pan (30) for receiving a sheet with a first outer leaf folded, and for folding a second outer leaf of the sheet inwardly toward a central portion as the sheet passes between associated rolls (20, 22). A gatefold pan (32) receives the sheet from between the rolls (20, 22). The gatefold pan (32) includes a deflector (62). The deflector (62) is movable, under control of actuators (64, 68), from a retracted position to an extended position into a path of travel of the sheet from the fold pan (30) to the gatefold pan (32). In its extended position, the deflector (62) serves to deflect the first outer leaf of the sheet toward the central portion of the sheet. Sensors (82, 84) are provided in the respective fold pans (30, 32) and are connected to actuator control means. In addition to causing retraction of the deflector (62) after the gatefolding of a sheet, the control means also prompts retraction of the deflector (62) under two error conditions. The first error condition occurs when two successive sheets are sensed as leaving the fold pan (30) without a sheet leaving the gatefold pan (32). A second error condition involves the detection of a predetermined time delay between the sensing of a sheet leaving the fold pan (30) and the sensing of a sheet leaving the gatefold pan (32).
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