Abstract: A paper feed mechanism for use in a printer has a pin tractor unit disposed on one side of a platen which is opposite to a print head, and a paper guide plate located below the pin tractor unit. The pin tractor unit has an endless tractor belt trained around a plurality of pulleys to form a first guide passage above the pin tractor unit and a second guide passage inclined from the first guide downwardly toward a position beneath the platen. The tractor belt has pins for fitting into perforations defined in the side margins of continuous paper. The continuous paper is inserted between the pin tractor unit and the paper guide plate, threaded between the platen and the print head, and then extended along the first guide passage. By moving the tractor belt in a prescribed direction, the continuous paper can be pulled by the pin tractor unit so as to be fed along in one direction.

Abstract: A wire dot-matrix printer has a print head which can be moved toward and away from a sheet or sheets of print paper by means of a stepping motor, the print head being movable from an initial position. The wire dot-matrix printer also includes a detector for detecting the thickness of the sheet or sheets of print paper by bringing the print head from the initial position into abutment against the sheet or sheets and then moving the print head back to the initial position, and a controller for determining the speed of movement of the print head with respect to a platen in parallel relationship thereto, based on information from the detector.

Abstract: A fan-folded type ink ribbon cartridge in which an ink ribbon is regularly folded to have a constant width and is enclosed in an enclosing space of a cartridge casing. This cartridge is provided with a plurality of projections which are arranged to face one another on the mutually facing inner surfaces of the cartridge casing near the outlet of the enclosing space of the cartridge casing. Each gap which is formed by the projections facing each other is set to be more narrow than the folding width of the ink ribbon. These gaps may be set to be constant or they may be set so as to gradually become more narrow towards the outlet of the enclosing space. The ink ribbon is hooked by the projections and the folding width is gradually reduced, so that the ink ribbon can be stably pulled out with minimal load variation. In addition, the ink ribbon is prevented from falling down due to the pressure of the inlet side of the enclosing space or due to the weight of the ribbon itself.

Abstract: An ink ribbon cartridge for use in an impact printer has a pair of spaced ribbon guide arms pivotally mounted on a cartridge case. An endless ink ribbon is stored in a storage space in the cartridge case. A feed roller is drivably mounted in the cartridge case. A roller guide is pivotally mounted in the cartridge case and has a hook engageable by a post on the rear end of one of the ribbon guide arms. A pressure roller is rotatably mounted on the roller guide and movable toward and away from the feed roller in response to angular movement of the roller guide. The pressure roller is normally urged by a spring to move toward the feed roller.