Web conveying device, printing apparatus, and tension control method

摘要

A control unit allows a rotational position of a tension generating roller to be changed depending on a width of a web at time of the beginning of conveyance of the web, controls a motor according to a detection signal of a second sensor such that a tension guide maintains its position within a predetermined range during conveyance of the web, causes position data at time of keeping the same value of the position data of the motor for a predetermined period to be stored, calculates an initial operational position of the tension generating roller using the position data and a predetermined correction coefficient, and sets the calculated initial operational position as an initial operational position of the tension generating roller at time of the beginning of next conveyance of web.

主权项

1. A web conveying device comprising:
a conveying mechanism to convey a web; a tension generating mechanism to impart tension to the web fed to the conveying mechanism, the tension generating mechanism including:
a tension generating roller to be rotationally driven by a motor about a rotation shaft eccentrically positioned;a first sensor to detect a rotational position of the tension generating roller;a pressing roller to press the web to the tension generating roller;a tension guide to rotate according to degree of tension generated on the web by the tension generating roller and the pressing roller; anda second sensor to detect a rotational position of the tension guide; and a controller configured to control the rotational position of the tension generating roller by controlling the motor according to detection signals of the first sensor and the second sensor, wherein the controller causes the rotational position of the tension generating roller to be changed depending on a width of the web at time of the beginning of conveyance of the web, controls the motor according to the detection signal of the second sensor such that the tension guide maintains its position within a predetermined range during conveyance of the web, causes last position data in a period in which position data of the motor continuously changes to be stored, calculates an initial operational position of the tension generating roller using the last position data and a predetermined correction coefficient, and sets the calculated initial operational position as an initial operational position of the tension generating roller at time of the beginning of next conveyance of the web.