PURPOSE: To provide a device for detecting the residual quantity of photosensitive pressure-sensitive sheets in an image device capable of detecting the residual quantity of the photosensitive pressure-sensitive sheet accurately irrespective of the feeding speed of the photosensitive pressure-sensitive sheet and its thickness in an image recorder using the photosensitive pressure-sensitive sheet.

CONSTITUTION: The quantity of the photosensitive pressure-sensitive sheets 11 is detected by detecting the presence of the photosensitive pressure-sensitive sheet with ultrasonic sensors 28, 29 and 30 from the cross-sectional direction of the roll-like photosensitive pressure-sensitive sheet 11 (in the direction parallel to a cartridge shaft). By displaying it, the residual quantity of the photosensitive pressure-sensitive sheet 11 can be shown to a user irrespective of the feeding speed of the photosensitive pressure-sensitive sheet 11 and the thickness of the photosensitive pressure-sensitive sheet 11.