Patent ID: 8526066
Filing Date: 2013-09-03
Classification: H03M

Abstract:
1. An analog processing circuit included in an image reading device, which is included in an image forming apparatus, the analog processing circuit comprising: an internal reference voltage; a first clamping unit configured to clamp a base voltage of an input image signal to a predetermined reference voltage obtained based on the internal reference voltage; a second clamping unit configured to obtain a reference signal from the internal reference voltage so as to have a same voltage as the predetermined voltage; a sampling-and-holding unit configured to receive input of the image signal after clamping and the reference signal, obtain a difference in the image signal after clamping and the reference signal as an image signal component of the image signal, and sample and hold an image signal consisting of the image signal component; an amplifying unit configured to amplify the image signal consisting of the image signal component obtained by the sampling-and-holding unit; and an analog-to-digital converting unit configured to convert the image signal after amplification into a digital image signal.