Sheet feeder suitable for feeding thick sheets

Claim 1

A sheet feeder comprising: a hopper housing or storing stacked thin or thick sheets, said hopper housing including a front opening perpendicular to a plane of said stacked thin or thick sheets; a pair of separator pawls provided on both edge portions of said front opening for separating an uppermost sheet of said stacked thin sheets, said separator pawls being apart from each other by a first distance; a thick sheet feeding attachment to be attached to said hopper housing when said stacked thick sheets are stored in said stacked thin sheets are stored in said hopper housing, said thick sheet fedding attachment including a pair of front walls to be located on said both edge portions of said front opening, each of said front walls being formed with a slit parallel to a plane of a uppermost sheet of said stacked thick sheets for permitting the passage of said uppermost sheet of said stacked thick sheets, said slits being apart from each other by a second distance smaller than said first distance whereby the separating function of said separator pawls is disabled y said front walls; pressure means provided on said hopper housing for pressing against feed roller means for advancing said uppermost sheet; whereby said hopper housing and said separator pawls are utilized for feeding thin sheets and said thick sheet feeding attachment in combination with said hopper housing is utilized for feeding thick sheet.