| 摘要 |
A printing apparatus includes an advancing circuit, such as a tractor, disposed on a first side of a printing head for feeding recording material. The printing apparatus has an improved tension circuit for providing adequate tension to the recording material in order to eliminate slack in the recording material, particularly during a manual feeding operation. Tension is provided by a motor driven driving roller which is disposed on a second side of the printing head opposite the first side. The driving roller is rotated in a direction in which tension is to be provided to the printing material by a tension motor. A rotary encoder, for example, is fixed to a rotating portion of the motor for driving a tractor which advances the recording material. The rotary encoder outputs position pulse signals indicating the displacement of the advancement elements. The tension motor is driven in response to the position pulse signals by a position feedback control operation performed by a control circuit. The tension circuit can also be employed in a printing apparatus which automatically advances recording material, thereby attaining the advantages set forth above.
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