Back tension mechanism and roll medium conveying device

摘要

A back tension mechanism includes: a shaft to be connected to an axle of a medium roll; a rotation transmitting member connected to the shaft via a torque limiter and having an engaging portion; a first rotating member having a first engaged portion configured to, when the rotation transmitting member rotates in a first direction, engage with the engaging portion to receive a rotational force; a second rotating member having a second engaged portion configured to, when the rotation transmitting member rotates in a second direction opposite to the first direction, engage with the engaging portion to receive a rotational force; an urging member for urging the first rotating member in the second direction and the second rotating member in the first direction; and a base for limiting a range of rotation of the first rotating member and a range of rotation of the second rotating member.

主权项

1. A back tension mechanism comprising:
a shaft configured to be connected to an axle of a rotatably supported medium roll and rotate in synchronization with rotation of the medium roll; a rotation transmitting member connected to the shaft via a torque limiter and configured to rotate coaxially with the shaft, the rotation transmitting member having an engaging portion for transmitting rotation of the rotation transmitting member; a first rotating member rotatably supported by the shaft, the first rotating member having a first engaged portion configured to, when the rotation transmitting member rotates in a first rotational direction, engage with the engaging portion to receive a rotational force of the rotation of the rotation transmitting member; a second rotating member rotatably supported by the shaft, the second rotating member having a second engaged portion configured to, when the rotation transmitting member rotates in a second rotational direction opposite to the first rotational direction, engage with the engaging portion to receive a rotational force of the rotation of the rotation transmitting member; an urging member for urging the first rotating member in the second rotational direction and urging the second rotating member in the first rotational direction; and a base rotatably supporting the shaft, the base having a first limiting portion for limiting a range of rotation of the first rotating member and a second limiting portion for limiting a range of rotation of the second rotating member.