Image forming apparatus

摘要

An image forming apparatus has rotatable members for rotatably retaining respective ones of flanges mounted to opposite ends of a roll sheet, and placement stages on which the roll sheet is to be placed and on which respective ones of the rotatable members are mounted. Racks are mounted to respective ones of the placement stages for undergoing movement to move the placement stages relative one another to vary a distance between the placement stages. A pinion is arranged between the racks for undergoing rotation to move the racks, and a potentiometer whose resistance value varies in accordance with a distance between the placement stages undergoing movement with rotation of the pinion is provided. An A/D converter outputs a value based on a resistance value of the potentiometer. A calculation device calculates a width of the roll sheet based on the value output from the A/D converter. A memory stores the calculated width of the roll sheet.

主权项

1. An image forming apparatus configured to receive and convey a roll sheet to an image forming unit to record an image on the roll sheet, the image forming apparatus comprising:
a pair of rotatable members for rotatably retaining flanges fixedly mounted to respective ones of opposite ends of the roll sheet; a roller for rotatably retaining the flanges together with the rotatably members; a pair of placement stages on which respective ones of the rotatable members are mounted and on which the roll sheet is to be placed, the placement stages being mounted for undergoing movement along a longitudinal direction of the roll sheet; a pair of racks mounted to respective ones of the pair of placement stages for undergoing movement to move the pair of placement stages relative to one another to vary a distance between the pair of placement stages; a pinion arranged between the pair of racks for undergoing rotation to move the pair of racks; a potentiometer whose resistance value varies in accordance with a distance between the pair of placement stages undergoing movement with rotation of the pinion; voltage detecting means for detecting a voltage value in accordance with a resistance value of the potentiometer; calculation means for calculating a width of the roll sheet based on the detected voltage value a lever arranged between the roller and the rotatable member of at least one of the pair of placement stages for undergoing movement in accordance with presence and absence of the flanges; a shaft extending through at least one of the placement stages and being mounted to undergo rotational movement in accordance with movement of the lever; a switch arranged at an end portion of the shaft; and roll sheet detecting means for detecting the presence and absence of the flanges in accordance with an output from the switch.