Contact-type image sensor having protrusions formed on a plate

Abstract

In a contact-type image sensor according to the present invention, a protrusion is formed in a transparent plate, a recess is formed in a sensor frame, and the transparent plate is engaged with the sensor frame so that the heights of surfaces of the transparent plate and the sensor frame on sides of conveying a manuscript are substantially the same. In conventional techniques, it was necessary to bend a manuscript conveying path because of different heights of a protrusion of the frame and the transparent plate. Further, even though the heights of the sensor frame and the transparent plate are the same, a contact portion therebetween forms an angle, whereby a contact surface is not brought into close contact alone an entire length of an image sensor, and gaps are partially formed in the contact surface. Therefore, at time of cleaning a surface of the transparent plate using a solvent such as alcohol to remove dirt on the transparent plate, the solvent and extraneous matters intrude inside the image sensor from the gaps, a passage of light is obstructed, and therefore light-and-shadow information of an image of the manuscript was not correctly transmitted to sensor.

Dependencies are inferred from the claim text.