Back tension imparting device
AssigneeRicoh Company, Ltd.
InventorTatsuo Nishikawa
Life of this patent
Estimating the term…
Abstract
A device for imparting back tension of a predetermined magnitude to the portion of strip material disposed between a take-up reel and a supply reel when the strip material wound at one end on the supply reel and at the other end on the take-up reel is paid out of the supply reel by rotating the take-up reel. The device has particular utility in an electrophotographic copying apparatus employing a photosensitive drum in which a strip of photoconductive film is interchangeably mounted and comprises a novel mechanism, light in weight and low in cost, which has the effect of imparting to the strip back tension which it is required to have when in use and yet enabling the strip to be advanced and wound on the take-up reel with the exercise of a force slightly in excess of the back tension present in the strip.
Claims7
A back tension imparting device for use in winding strip material comprising:
- a. a take-up reel on which one end of said strip material is wound;
- b. means for preventing rotation of said take-up reel in the direction in which the strip material wound thereon recoils;
- c. means producing a driving force for driving the take-up reel to rotate in the direction in which the strip material is advanced and wound on the take-up reel;
- d. a supply reel on which the other end of the strip material is wound and comprising a first rotatable shaft;
- and
- e. means for urging the supply reel to rotate in a direction in which back tension is imparted to the strip material, said urging means comprising:
- i. a second rotatable shaft disposed in alignment with said first rotatable shaft;
- ii. means for connecting said first and second shafts for rotation as a unit, comprising a coil spring surrounding and tightly engaging said first and second shafts and having one end connected to said second shaft;
- iii. means for applying a back tension force to said second shaft to urge it to rotate in a direction in which back tension is imparted to the strip material;
- and
- iv. means connected to the other end of said coil spring for loosening said coil spring when the driving force on said strip material from said driving means exceeds the back tension force on said second shaft to permit rotation of said first shaft with respect to said second shaft and against the frictional force applied by said coil spring.
Dependencies are inferred from the claim text.