Patent ID: 7584951
Filing Date: 2009-09-08
Classification: B65H

Abstract:
1. A conveying device including a sheet feed roller and a conveying roller which are driven by a DC motor, and controlling the DC motor based on information obtained from an encoder mounted to the conveying roller, the conveying device comprising: a transmission unit having a transmission state in which a driving force transmitted from the DC motor for driving the conveying roller is transmitted to the sheet feed roller and a non-transmission state in which the driving force is not transmitted to the sheet feed roller, the transmission unit being configured to switch between the transmission state and the non-transmission state based on a rotating direction of the DC motor; a first driving unit configured to drive the DC motor in a first amount of driving in a first direction to convey a sheet up to the conveying roller when the transmission unit is in the transmission state; a counting unit configured to count a number of slits of the encoder; a first determining unit configured to determine the occurrence of an error with respect to the sheet feed roller based on a count value counted by the counting unit during the driving of the first driving unit; a second driving unit configured to drive the DC motor in a second amount of driving in a second direction opposed to the first direction to convey the sheet up to a position downstream of the conveying roller in a conveying direction when no error is determined by the first determining unit; a third driving unit configured to drive the DC motor in a third amount of driving in the second direction when the occurrence of an error is determined by the first determining unit; and a second determining unit configured to determine one of a plurality of error types based on the count value counted by the counting unit during the driving of the first driving unit and the count value counted by the counting unit during the driving of the third driving unit, wherein the first determining unit makes the determination based on the count value counted per unit time by the counting unit during the driving of the first driving unit.