摘要 |
An image reading apparatus in which a CIS is pressed by springs to cause abutment members to abut the lower surface of an original support glass, wherein the abutment members are arranged within the main scanning reading range of the CIS and, more specifically, at positions where the deflection amount of the original support glass with respect to the end portions of the main scanning reading range is approximately ½ of the maximum deflection amount. Thus, when the original support glass is deflected, the CIS is pressed down against the spring force by approximately ½ of the maximum deflection amount in the main scanning reading range of the original support glass from the position where the original table has no deflection, whereby the optimum focal position of the CIS is downwardly shifted and as the result, the upper surface of the original support glass constituting the original surface is retained within the effective focus range of the CIS over the entire main scanning reading range, thereby making it possible to perform high quality image reading.
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