Patent ID: 7667745

Claim:
A signal detecting system for reading a charge signal from an image recording medium in which image information has been recorded as a charge signal comprising a signal storing circuit which stores the charge signals, a first low-pass filter into which at least one of the charge signals stored in the signal storing circuit is input, a first sample hold circuit which sample-holds the charge signal passing through the first low-pass filter, a second low-pass filter into which at least one of the charge signals stored in the signal storing circuit is input, a second sample hold circuit which sample-holds a reference level signal when the input of the charge signal passing through the second low-pass filter is at a reference potential, a difference means which outputs as an image signal the difference between the charge signal output from the first sample hold circuit and the reference level signal output from the second sample hold circuit, and a control means which controls the sample hold initiating timings at which the first and second sample hold circuits initiate their sampling, wherein the control means controls the first and second sample hold circuits so that the initiating timing of the first sample hold circuit is earlier than that of the second sample hold circuit; and wherein the first sample hold circuit passes the charge signals during an overlapping time period with a reset switch being open and the second sample hold circuit being turned off.