Mannesmann Aktiengesellschaft

Wolfgang Hendrischk

Gerhard Nolte

Gunter Gomoll

Hubert Ott

Manfred Gruner

Horst Heisele

Werner Rupp

Lorenz Fromme

Wolfgang Seybold

Gerhard Schrader

Alexander Voigt

Karl Mayr

A printhead for dot matrix printing has several styli arranged in one or two vertical columns so that the tips are arranged in one or two mouthpieces being independently movable. High-speed printing operates with a matrix per character having a number of horizontal line positions and as many vertical print positions as there are styli in a column. High-quality printing involves increasing the resolution in both directions, the number of horizontal positions possibly exceeding the number of vertical positions (the latter being an integral multiple larger than one of the numbers of styli in one column). Various structures are disclosed to shift one or two such mouthpieces in vertical direction.

Shiftable guide for a matrix printhead

The platen roller in a matrix printer is mounted to the printer case so that stop plates of the mount define a representation of the disposition of the roller. A frame is provided to hold a guide rod on which rides a carriage, and the print head is secured to that carriage. Adjustable cams on the rod abut the stop plates when the frame is slid into the case to, thereby, establish the distance between head and platen. The frame carries also the head drive, its motor and the paper-feed motor, there being a key connection to the platen, maintaining a driving connection even for different cam adjustments and frame positions in the case.

Adjustment of print position

The printer is constructed for multiple merging feed paths sharing a pivotable brake and by means of adjustably mounted different sets of rolls different combinations in the disposition of the rolls and the brake vis-a-vis the platen drum different modes of transportation are attainable.

Transporting sheet stock in printers

A matrix printer is operated with a multicolor band ink ribbon which changes position vis-a-vis print styli. Through a combination of paper shifts and ribbon position shifts, as well as selective control of the styli, multicolor areas are sequentially composed.

Multicolored printing

The printer includes a common feed and eject portion constructed as friction belt drive; it further includes a friction drum and a print head and cutter between the drum and the ejection portion which participates in the advance during printing but runs a little longer than the friction drum to hold the paper taut. This period is extended during advance after printing the last line to tension the paper during cutting. The combination of feed and eject permits front end feeding and ejection.

Printer

The print head of a matrix printer includes two columns of print wires held in separate members which are individually vertically displaceable as well as together in order to obtain different conditions for printing. Good quality or high-speed modes can be obtained in a single pass, high quality in two passes, or a single pass with alternating, vertical displacement of the members for each print position.

High-quality/high-speed matrix printing

Two friction rolls are journalled on a driven shaft, and a differential being keyed to that shaft causes that one of the rolls to be driven which is not held. The rolls are alternately held by, preferably, latching devices which are operated on limit positions of the print head.

Drive for friction rolls in printers

A pivoted ink ribbon guide in front of a matrix print head is positioned by a lever linkage which translates the four different combinations of energization stages of two solenoids into four different alignment positions for a multi-colored ink ribbon.

Positioning of a multicolor ribbon

A printer is provided with a single drive shaft mounted on plural bearings and carrying a plurality of axially aligned, individually rotatable, hollow friction rolls, each containing an electromagnetic brake and a coupling for connecting the roll to the shaft. The electromagnets are operated independently for the several rolls and feelers are disposed upstream of the paper webs to operate the brake when sensing a marking or the end of a roll of paper separately for each roll.

Friction drive in printers

A matrix printer, having a movable print head, a paper feed and advance mechanism and an ink ribbon system, is driven by two motors; one for the print head and one for paper feeding and ribbon movement. This second motor is a reversible one and drives the paper advance when rotating in one direction and the ink ribbon when rotating in the opposite direction. Speed control for the paper feed phase is derived from a cam on the input shaft for the paper advance. A reset mechanism for that shaft is also included.

Combined paper advance and ink ribbon feed system

A one-arm sensing lever having a sensing cam and carrying a permanent magnet faces a spring-biased, two-arm rocking lever across the paper-feed path of a printer; in the absence of paper, the cam drops into the feed path and the magnet is now capable of attracting one arm of the rocking lever so that its other arm operates a switch.

End-of-paper sensing device

A print head for matrix printing has twelve needles whose front ends are arranged in three columns and seven rows, whereby the middle one holds only two needle ends in the second and sixth row, while the other row positions each of the two outer columns hold one needle tip. This arrangement permits a significant print speed increase for a moderate weight increase, and reduces the number of weak spots in the needle guiding mouth piece.

Matrix print head

The printer is provided for alternative use with long webs or individual, precut forms; it includes two friction roll drives adjacent to the print head and platen, and a sprocket drive upstream, being permanently engaged with a perforated web. The drives operate in synchronism but do not participate in all operations. Printing on the web is carried out after advancing the web by one form length and retracting it during stop and go printing. Switches control access to a bypass, the insert for a single form, and a receiver tray, into which any printed form drops.

A web is cut in a printer by a carriage driven stepped roll being urged against a stationary cutting edge so that a tear point travels ahead of the engagement of the roll with the edge and the paper. The roll can be retracted and latched into a non-cutting position.

Cutting of paper in a printer

A matrix printer with a reciprocating carriage carries transversely moving spring biased printing head. A roller on the head runs on a resilient rail urged against the platen and can be retracted by pivoting the rail carrier under engagement of a second rail cooperating with a second roller on the head. A cam track in a terminal position of the carriage provides for independent head retraction through engagement with the second roller.

Growing community of inventors

Neu-Ulm, Germany

Wolfgang Hendrischk