Patent ID: 7712739

Claim:
A conveying apparatus comprising: a conveyor belt formed as a loop configured to convey an object, the conveyor belt including a linear encoder having a linear scale provided on a rear face of the conveyor belt; a driving part for driving the conveyor belt, the driving part including a rotary encoder having a resolution higher than the linear encoder of the conveyor belt; a control part configured to calculate a required number of pulses of signals output from the linear encoder and the rotary encoder for moving the conveyor belt a predetermined amount, by using a formula of N=a·n 1 +n 2 ; wherein “a” is a correlation function representing a ratio between “L 1 ” and “L 2 ”(a=L 1 /L 2 ), wherein “L 1 ” is the amount of conveyance of the conveyor belt corresponding to a single pulse of a signal output from the linear encoder, wherein “L 2 ” is the amount of conveyance of the conveyor belt corresponding to a single pulse of the signal output from the rotary encoder, wherein “n 1 ” is the number of pulses of the signals of the linear encoder having the lower resolution, wherein “n 2 ” is an integer that satisfies a relation of 0≦n 2 <a; wherein the control part controls the amount of conveyance according to the number of pulses of signals n 1 and n 2 output from the linear encoder and the rotary encoder; wherein the linear encoder includes a first sensor positioned within the loop of the conveyor belt for reading the linear scale provided on the rear face of the conveyor belt.