Abstract: A thermal transfer type printing apparatus includes a monochromatic printing section and multi-color printing section. The monochromatic printing section includes a thermal head unit for thermally transferring an ink layer of a black ink ribbon onto a paper sheet according to a black image signal. The multi-color printing section includes a thermal head unit for successively transferring cyan, magenta and yellow layers of a multi-color ink ribbon in an overlap state onto the paper sheet according to image signals for the respective colors.

Abstract: In a developing apparatus, a conveyor for conveying developer particles supplied from developer supplying means defines a gap with the surface of a photosensitive body. A developer supplying passage for conveying the developer particles is provided between the developer supplying means and the gap. The developer supplying passage is defined by the conveyor and an electrode plate provided at a predetermined interval with the conveyor. An alternating electric field is applied to the developer supplying passage by an A.C. power source to reciprocate the developer particles between the conveyor and the electrode plate, thereby sufficiently and uniformly charging the developer particles by friction.

Abstract: A scanner scans a document to produce the document information. A memory stores the document information of many documents and their associated retrieval code data. By specifying the retrieval code data, the document information related to the retrieval code data is read out from the memory. An optical fiber cathode ray tube converts the read-out document information and associated retrieval code data into a corresponding optical image. An electrographic printer reproduces the optical image in the form of a visual image including the document and its related retrieval code.