Centronics Data Computer Corporation

Prentice I Robinson

Robert Howard

Alexander F Vitale

Paul A Lavoie

Paul S Ramsden, Jr

Thomas T Butterfield

A drive assembly for printer carriages and the like comprised of a closed looped metallic tape entrained about a drive and a driven pulley and being moved at a substantially constant rate. The carriage assembly reciprocally slides along guide rods for linear movement in a forward and reverse direction and is provided with guideways for enabling substantially unimpeded movement of the upper and lower runs respectively of said closed looped tape. Solenoid operated jam cleat assemblies are respectively engageable with the upper and lower runs of said closed looped tape in a mutually exclusive fashion. Connecting rod means is provided to assure engagement of only one of the jam cleats with the associated run of the closed loop tape to prevent stopping or jamming of the tape and to assist in the release of the deactivated jam cleat. By selective energization of the pair of solenoid assemblies, the carriage assembly may be moved in either the forward or reverse direction at any given instant of time. A dot matrix print head may be mounted upon the reciprocating carriage assembly which by appropriate utilization of printer electronics, may be utilized for either unidirectional or bidirectional printer systems.

Bidirectional carriage drive employing a closed loop belt drive means

An inkjet printer is provided with a movable carriage upon which is mounted an inkjet print head and a small reservoir having a fluid capacity capable of printing a predetermined number of characters, and which is sufficiently light in weight as to minimize the mass mounted upon the carriage. Sensing means detect the low level of ink for causing the carriage to be moved to the end of one of the printer margins at which is located a stationary large capacity ink reservoir having an outlet nozzle adapted to be inserted into an opening in the small capacity reservoir for filling the reservoir either under control of a pump or by gravity feed, whereupon the printer resumes the printing operation.

Method and apparatus for filling the movable reservoir of an inkjet

An opaque flag mounted upon a printer carriage assembly interrupts the light emmitted by a LED from reaching a phototransistor when at the left-hand margin of the paper document. The carriage starts to move and when it reaches constant print velocity, the opaque flag moves away from the LED and the phototransistor to activate the phototransistor to trigger a gated oscillator to generate pulses of very uniform size and shape and preferably of a 50% duty cycle. The leading and trailing edges of the pulses from the gated oscillator generate strobe and delay strobe pulses of shorter pulse duration which, in turn, energize the wire actuating solenoids forming full-step and half-step dots the full-step dots creating characters within a 5 .times. 7 dot matrix and both the half-stepand full-step dots being forming characters within a 9 .times. 7 dot matrix. When printing is completed, a PRIME signal resets and abruptly stops the gated oscillator. The carriage is returned to the left-hand margin doing so, moving the flag between the LED and the phototransistor to decouple the drive from the carriage assembly before reaching the left-margin and enable the carriage to coast to a stop. The sequence is repeated for each line of print.

Registration means for printers and the like

A printer of the dot matrix type for printing, single, double and triple sized characters. Normal sized characters are printed in the conventional fashion. Double and triple sized characters are printed through a segmented technique in which segments of the double and triple sized characters are stored within readable memories (ROMS). For double sized characters which occupy two adjacent character lines, the segmented patterns for the upper portions of the characters are printed along the first normal sized character line. The lower half of the double sized characters is printed on the next adjacent character line by selection of the appropriate segmented patterns. Triple sized characters are printed in a similar manner, utilizing three lines of conventional sized characters. The same technique may be employed to create other graphic patterns of 1 to N lines, where N is a real integer equal to or greater than 2. The technique permits the utilization of either unidirectional or bidirectional printers.

Method and apparatus for printing segmented characters

An impact printer of the dot matrix type capable of printing in either the forward or reverse direction. Means are provided for determining the position of the print head at any given instant. Upon completion of a line of print the print head is abruptly halted. The next line of characters is examined to determine the end points of its character field. Comparisons are made to determine whether the print head lies within or beyond the end points. In cases where the print head lies beyond the end points of the character field, the printing occurs by moving the head in a direction toward the closest end point and then printing. If the print head occupies the location between the end points the position of the head is loaded into a pair of counters which are simultaneously counted up and down respectively. The outputs of the counters are continuously compared against the values representing the end point locations whereupon the first favorable comparison determines the shortest distance of print head travel for starting printing. High speed electronic circuitry is provided for storing data representing the next line to be printed in both forward and reverse formats whereupon the decision as to the direction in which data is printed automatically controls the appropriate storage medium. Novel video detection means is provided both for determining the direction of head movement at any instant and for controlling the printing positions. The use of delayed strobes derived directly from the video control allows printing to start immediately from the rest position, and provides accurate registration of delayed strobes relative to strobe pulses regardless of the velocity of the carriage. The printer has the ability of printing expanded characters and includes electronic circuitry to prevent data in the expanded character format from being lost in cases where the inputted data representing the expanded character format exceeds the print line capacity of the printer whereby any overflow will automatically be printed on the second succeeding line of print.

Growing community of inventors

Pelham, NH, United States of America

Prentice I Robinson