Abstract: The present invention is intended to provide an economical printer which is simple in structure and uses a common tray but is capable of adapting itself to various recording media of different shapes. Adapters in which recording media can be firmly held can be selectively mounted in the tray. An adapter 24 has an oval opening 24a in which a recording medium 30 can be placed. The contour of the adapter 24 can fit into a recessed portion 23a formed in the tray 23. The recording medium 30 is firmly held in the adapter 24. When the adapter 24 is mounted in the recessed portion 23a in the tray 23, a keyway 23b and a protrusion 24b engaging the keyway 23b prevent the adapter 24 from shifting out of position; the adapter is held in the tray 23. Prints can be made in accurate positions on the recording medium 30.

Abstract: A double-side printing system has a printer section for printing images on the obverse side of a card, and a turning section for turning over the card sent out from the printer section and sending back the inverted card to the printer section so as to print various images on the reverse side of the card. The printer section performs printing of smooth color gradation images such as photographs with dye-sublimation color inks, and binary gradation images such as bar code patterns and letters with monochromatic thermal wax-transfer ink. The card having its obverse side printed with images is sent to the turning section and turned over 180.degree. so as to print other images on the reverse side of the card.

Abstract: A workpiece such as a paper or a card is held in proper position in a typewriter having a paper scale for typing to the bottom of the workpiece without side slippage by the inventive workpiece holders. Each of the pair of holders mounts fixably, detachably, and slidably flush with the outer surface of the paper scale and has an inner member positioned when mounted such as to be parallel to the outer surface of the paper scale and at a suitable distance out and on each side of the workpiece for free movement of the workpiece between the member and the outer surface of the paper scale.