Signal reading circuit for masked and overlapping linear image sensors

Claim 1

A signal reading circuit for linear image sensors, comprising: a linear image sensor unit including a plurality of linear image sensors at different locations transverse to a main scanning direction of said linear image sensors, each linear image sensor having a plurality of photoelements arranged along said main scanning direction, and an opaque metalization mask covering at least one photoelement at a first end of said each linear image sensor; a plurality of A/D converters in an A/D conversion unit digitizing in parallel outputs of said linear image sensors; a line memory comprising a plurality of storage elements receiving respective outputs of said A/D converters, each of said storage elements having a number of sequentially arranged storage elements of a number not less than an effective number of photoelements of a corresponding one of said linear image sensors, said effective number being no more than the number of photoelements being not covered by said opaque metalization mask; means for sequentially writing in parallel into said storage elements output signals of said A/D converters, said sequential writing being of data derived from respective ones of said linear image sensors beginning at said first ends thereof, said sequential writing being performed into sequential ones of said storage locations beginning at an intermediate storage location of each of said storage elements, proceeding to first ends of said storage elements and continuing from a second end of said storage elements.