Abstract: An apparatus is capable of reading a character or graphics image on a document at a plurality of reading linear densities. An illuminating device for illuminating the document, a focusing device for focusing the light beam reflected by the document, and a CCD reading sensor for converting the focused light beam into an electric image signal, are integrally assembled together to constitute a carriage device. This carriage device is shifted in a desirable shifting which is determined on the basis of the reading sensitivity of the CCD reading sensor and which corresponds to the linear reading density. The rotation speed of a driving device used for driving the carriage device is reduced to a desirable value by means of a transmission, the conversion ratio of which is determined on the basis of the least common multiple (LCM) of a plurality of reading linear densities. The driving pulses which should be supplied to the driving device can be easily calculated by use of the product of the "reference pulse " .phi.

Abstract: A line sensor apparatus is adapted to read a character or pattern image on a document. In this apparatus, an illumination device for illuminating the document, a optical lens for focusing the light beam reflected by the document, a CCD line reading sensor for photoelectrically converting the light beam focused by the optical lens into an electric signal, and a holding member for holding the CCD line sensor and the optical lens are assembled as one body in such a manner as to constitute a carriage device. A uniformly radiated heat-radiating plate is in contact with the entire botttom surface of a support for the CCD line sensor, so that the heat generated by the CCD line sensor is radiated from the heat-radiating plate. Further, the CCD line sensor is kept in tight contact with the holding member, so that the heat generated by the CCD line sensor is also radiated from the holding member.