Alignment device

An alignment device for use in a bag making apparatus for making bags from a first continuous sheet panel, a second continuous sheet panel, and additional components, both of the first and second continuous sheet panels having print patterns that repeat at a print pitch and each include a detection point therein, wherein design positions are predetermined on each of the first and second continuous sheet panels at the print pitch,

• the alignment device comprising:
• a first feed device configured to intermittently feed the first continuous sheet panel;
• a second feed device comprising a feed unit configured to intermittently feed the second continuous sheet panel and a stretching unit disposed downstream of the feed unit to apply tension to the second continuous sheet panel in an adjustable manner;
• a pair of guide rollers disposed downstream of the first and second feed devices;
• a third feed device disposed downstream of the pair of guide rollers to intermittently feed the first and second continuous sheet panels superposed on each other by the pair of guide rollers;
• a first fixing device configured to fix an additional component to the first continuous sheet panel at a first fixing position downstream of the first feed device and upstream of the pair of guide rollers during every pause phase of an intermittent feed cycle;
• a second fixing device configured to fix the second continuous sheet panel to the additional component at a second fixing position downstream of the pair of guide rollers and upstream of the third feed device during every pause phase of an intermittent feed cycle;
• a first sensor for detecting the detection point of the first continuous sheet panel at a position downstream of the first feed device and upstream of the pair of guide rollers;
• at least one second sensor for detecting the detection point of the second continuous sheet panel at a position upstream of the second fixing device;
• and
• a third sensor for detecting the detection point of the first continuous sheet panel at a position downstream of the second fixing device and upstream of the third feed device,
• the first feed device being further configured to adjust an intermittent feed amount thereof based on output of the first sensor such that a design position of the first sheet panel is aligned with the first fixing position during every pause phase of an intermittent feed cycle,
• the third feed device being further configured to adjust an intermittent feed amount thereof based on output of the third sensor such that the design position of the first continuous sheet panel is aligned with the second fixing position during every pause phase of an intermittent feed cycle,
• the second feed device being further configured to adjust the tension and an intermittent feed amount of the feed unit based on output of the at least one second sensor such that a design position of the second continuous sheet panel is aligned with the second fixing position every pause phase of an intermittent feed cycle,
• wherein the at least one second sensor comprises a downstream sensor for detecting the detection point of the second continuous sheet panel at a position downstream of the pair of guide rollers and upstream of the second fixing device, and
• wherein the stretching unit is configured to adjust the tension in response to output of the downstream sensor.