Abstract: A system for automatically adjusting the print head gap of an impact printer, particularly for paper stocks of differing thicknesses and multi-layer forms, provides for measurement of an absolute distance between an undeflected platen position and a home position of the print head. Paper stock thickness is measured by measuring the distance to the home position from a position of the print head when a predetermined force is exerted by the print head against the platen. Since a similar measurement is made when paper stock is not present in the printer and using the same force against the platen, platen flexure is removed as a source of error and a standardized force is available for compression of the paper stock during measurement. Improved accuracy is achieved at high speed while avoiding the use of position encoder/decoder arrangements. A wider range of manufacturing variations in printer geometry and rigidity can be accommodated with uniformly improved print quality.

Abstract: Apparatus for selectively reinking an endless ribbon in that portion of the ribbon known as the ribbon print track. The ribbon print track is created in an endless ribbon by the repeated striking of the ribbon by a print mechanism thereby deforming the ribbon and depleting it of ink. Reinking the entire ribbon uses more ink than is necessary. Reinking only the print track extends the life of the ribbon by selectively using the available supply of ink. The apparatus achieves this result by use of an ink reservoir which supplies ink to a drive roller, which through a rotating pinching movement in cooperation with another roller, advances a ribbon into a stuffing cavity of an ink cartridge. The ink reservoir is rotatably mounted and formed to apply ink only to that portion of the drive roller which corresponds to the print track of the ribbon.

Abstract: A ribbon cartridge for an endless ribbon used in high speed printers, with increased reliability due to fewer parts, is constructed from a molded casing which is rectangular in shape into which are formed a post on which a cylindrical porous ink reservoir is mounted, a ribbon protector which isolates the ink reservoir from the ribbon in the stuffer box portion of the cartridge, and a forked bracket for mounting a shaft on which gears are mounted. A combination gear for driving a ribbon into the stuffer box and for re-inking the ribbon is mounted on a post and then rotatably mounted on the bracket formed into the housing and is inked by contact with the ink reservoir. An idler gear is rotatably mounted on a bracket which is pivoted from a socket molded into the socket wall and is spring biased into contact with the drive and transfer gear, which is turned by its extended shaft advance and ink the ribbon. As a result a simplified re-inking arrangement is achieved with the minimum of components.

Abstract: A feed mechanism for moving a web is disclosed. It includes a means for engaging the web that has a plurality of uniformly spaced drive pins for extending through and engaging web perforations. It also includes a means for guiding the web onto the drive pins, such as a door, and it includes a guiding surface that extends below the upper end of the pins. The guiding surface includes a static protrusion that extends below the guiding surface and urges the web and its associated perforation down onto the drive pin in that portion of the tractor where the drive pins are inserted into the web perforations.

Abstract: The present printer is adapted to be easily equipped with removable and interchangeable paper feed modules of several different types. Each of the paper feed modules is specifically adapted to feed a particular type of paper through the printer and each is easily replaceable by the purchaser of the printer to be used for feeding a specific type of paper therethrough. The printer is provided with a main frame including a pair of side support members and an elongate platen extends between the side support members and is fixed at opposite ends thereto. Three different types of removable and interchangeable paper feed modules are illustrated in the present application and each includes a pair of elongated end plates with a paper moving mechanism supported intermediate the elongated end plates.

Abstract: A ribbon positioning mechanism comprises a ribbon cartridge, a nosepiece, a stepper motor and flexible ribbon guides connecting the ribbon cartridge to the nosepiece. The nosepiece has two side members connected by a bridge, one of which has a downwardly extending leg. A rack located on the bottom of the leg engages a pinion attached to the stepper motor for lifting the nosepiece into a desired position. A ribbon, having a plurality of parallel color bands, passes from the ribbon cartridge via the flexible ribbon guides and through the nosepiece where it is aligned with a print head. The nosepiece freely slides on vertical guide posts attached to a print head carrier and printer logic controls the stepper motor to align the desired color band with the print head.

Abstract: A forms feed tractor belt includes drive members molded around a thin, flexible band at longitudinal intervals. To make the belt, slots are first punched at longitudinal intervals in at least one side of the flexible band. Drive members are then molded around the band at the slots except for at least one drive memberless interval at each end of the band. The ends of the band are overlapped so that the slots of the drive memberless intervals coincide. Final drive members are then molded around the slots of each pair of coincided drive memberless intervals to complete the endless tractor belt.

Abstract: There is disclosed herein a forms feed tractor mechanism having a belt with pins and driving elements extending threrethrough. The pins are adapted to engage perforated holes along the edge of a recorded medium. Driver means are provided for rotating the belt and pins and thereby rotate the engaged medium. Also, there is provided a spring tensioner for maintaining tension on the belt. The tractor includes a door which is rotatably snapped fitted into the housing of the tractor and maintained above the plane of the record medium by an extension on the lower surface thereof. The belt and pins are constructed by molding the pins around the belt side so that the belt is below the feeding surface of the tractor mechanism upon which the paper rests.

Abstract: In a printing system employing a spliced endless print ribbon, an opening is provided in the ribbon adjacent the splice to enable sensing of the approach of the splice to the print station. Printing is suspended as the splice passes the print station to avoid undesirable printing quality and damage to the splice. The same sensing means detects lack of ribbon movement, indicative of a ribbon jam, to suspend printing and ribbon drive.

Abstract: There is disclosed herein a dot matrix tilting print head assembly in which the print head is rotatably mounted in frame means. Solenoid means are provided for rotating the print head a controlled distance so that printing occurs between previously printed dots. Means are provided for controlling the distance to be one half of the center-to-center distance between printed dots. This entails maintaining very low tolerances for the mechanically moving parts. In addition, there is provided means for removing the print head alone from the frame means.

Abstract: A user replaceable printer ribbon shield of simple design is provided for use in high speed matrix printers utilizing continuous forms. The shield is detachably mounted. During printing, the shield prevents outfolds in the forms from catching on the ribbon and prevents ribbon ink from migrating to the forms. It moves with the platen slightly away from the matrix print head when the machine is idle for at least a preset period of time. This causes the ribbon to move away from the ends of the print wires in the matrix print head to keep print wire lubricatng oil from migrating to the ribbon.

Abstract: There is disclosed herein a dot matrix tilting print head assembly in which the print head is rotatably mounted in a frame. A solenoid is provided for rotating the print head a controlled distance so that printing occurs between previously printed dots. A pin extending from the print head is positioned into a larger diameter hole in the frame for controlling the distance to be one half of the center-to-center distance between printed dots. This entails maintaining very low tolerances for the mechanically moving parts. In addition, there is provided support members for allowing the removal of the print head alone from the frame means.

Abstract: An improved mechanism is provided for preventing long-term oil contamination of the print ribbon in a wire matrix printer. In the event that the print ribbon has an excess of oil thereon, it will cause the printed characters to be alternatively too light or too dark thereby reducing the print quality on the document. The print head of the wire matrix printer is operated to an idle or at rest position when printing is not being effected, a camming mechanism retracts the print head away from the platen and document. When this occurs, a stationary member on the printer carriage engages the ribbon and moves it away from contact with the print head in the vicinity of the apertures through which the print wires are guided for printing. With the ribbon moved away from the apertures, the lubricant oils on the print wires do not flow on to the ribbon. The retracting of the print head away from the platen and document by the camming mechanism also permits the easy insertion of new forms into the printer.