Abstract: In the paper feed mechanism disclosed herein, a pick roller is journaled in a swing member which is pivoted on a horizontal drive shaft extending across the paper path. The periphery of the pick roller frictionally engages the drive shaft and the swing mechanism depends from the drive shaft through a friction fit. When the drive shaft is rotated in the appropriate direction, the pick roller is swung, due to the frictional fit, against the front sheet of a paper pack and continued rotation of the shaft drives the pick roller into wedging engagement with the sheet, causing the sheet to advance and separate from the pack.

Abstract: In the calligraphic printing apparatus disclosed herein, a writing stylus is carried by a flexing suspension including a pair of generally orthogonal arms, each arm being driven by a respective servo system which responds to stored data representing characters to be written. The naturally arcuate path defined by each arm is substantially linearized by mixing into the drive signal for each servo system a compensating signal which is a function of the absolute value of the position signal controlling the servo system for the other arm.

Abstract: An electronic interface for operating a dot matrix printer to print a pattern appearing on a television screen employs video-type signals incorporating field and line sync signals, digitized image signals representative of dots of information along each raster line and dot pulses for synchronizing the digitized image signals. Upon receipt of a print request, a line address counter is incremented by each line sync pulse. A second counter, which is incremented each time the line address counter reaches a maximum count, has its count set into a horizontal position counter at the beginning of each line scan and is decremented synchronously with the dot pulses. The sequentially received dot information is loaded serially into a shift register and is transferred byte-wise in parallel into a location in a random access memory identified by the count in the line address counter when the horizontal position counter reaches a zero count.

Abstract: In the printer disclosed herein, shifting of a multi-color ribbon carried on a movable carriage is effected by differentially adjusting the free length of a cable extending parallel to the carriage motion. The cable passes over at least a pair of pulleys on the carriage, at least one of the pulleys being movable with respect to the other in response to changes in the free length of the cable. Solenoids are provided at each end of the cable for controllably changing the free length of the cable, the amount of change being different for the two solenoids so that four different combinations of free length are available. A ribbon shifting mechanism is coupled to the movable pulley so that the multi-color ribbon is shifted in accordance with the free length of the cable.

Abstract: An assembly for mounting a print head upon a carriage having an adjustable collar and a slotted support which receive opposing ends of an elongated shaft secured to the print head. The shaft is accurately positioned on the carriage by means of openings in said collar and said support which receive cooperating portions of said shaft. A spring biased cylindrical member retains the shaft within the carriage support and the collar. The collar is provided with a pair of projections which are engaged by the cam surface of a cam member rotatably mounted upon the shaft for adjusting the axial position of the print head relative to said collar and hence relative to a web supporting platen. The forms thickness setting assembly is accurately adjusted simply by axial adjustment of the collar, to assure the accuracy of all forms thickness settings through only a single adjustment step.

Abstract: A computer controlled impact printer has a replaceable ribbon guide assembly mounted on a printhead. The assembly is movable vertically between at least two stable positions. Each position places a differently colored portion of the ribbon between the printhead and a sheet of paper. Rotation of a pair of opposed cams changes the vertical position of the assembly. One cam is fixed and the other is rotatable by a pawl operating on a ratchet wheel secured to the cam. The pawl is mounted on the assembly for a longitudinal sliding movement. Movement of the printhead to a preselected position at or near one end of its travel path drives the pawl into an abutment surface which displaces the pawl a predetermined distance. The displacement rotates the movable cam from one stable vertical position to another. The mating cam surfaces preferably have matching sawtooth configurations with recesses formed in the tips of the teeth of one cam.

Abstract: An improved paper feed roller assembly for the paper feed mechanism of a printer is provided with an adjustable arrangement so that a plurality of different widths of perforated edge paper may be accommodated thereby. The arrangement includes a rotatable member having a plurality of indentations which cooperate with stops to select an axial position for the feed pins mounted on the roller, corresponding to the selected indentation.

Abstract: Fanfold paper emerges from an outfeed slot in a printer along a paper guide extender and falls by gravity into a paper basket to resume its original fanfold configuration. The paper slides between the extender and an upper paper forming guide which is slightly curled at its lower end to force the paper against the lower end of the paper guide extender to cause the paper to neatly fan fold within the basket.A wedge-shaped member is preferably provided upon the floor of the paper basket to urge the stacked paper into an inverted, slighty V-shaped configuration to further assure neat stacking and prevent corners of the paper from catching a perforation in the paper which would otherwise prevent neat stacking.

Abstract: Open-loop means for controlling the speed of a d.c. motor controlled print head moving across a document. A switch couples a first voltage to the d.c. motor to accelerate the print head in a first direction. When the print head reaches the desired velocity, the first voltage is decoupled from the motor and a highly regulated voltage is coupled to the d.c. motor to move the print head at the desired velocity. The switch reverses the voltage polarity at the input terminals of the d.c. motor to decelerate the print head, accelerate it in the opposite direction and maintain the desired velocity as it moves in the reverse direction. Logic means detects the direction of carriage movement and connects the first voltage to the d.c. motor for an interval sufficient to bring the d.c. motor to the desired speed in the shortest practical interval. The second voltage maintains the constant speed until the print head reaches the end of the line.

Abstract: 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.

Abstract: Color control means for selectively positioning one color of a two-color ribbon between a document-supporting platen and a print head having means for selectively impacting the desired ribbon portion against the document, said color control means comprising a color-select solenoid energized by logic circuitry responsive to a print-color signal. The solenoid is energized to a first position to enable characters of a first color to be printed at selected positions along a line. The logic circuitry includes means for selectively deleting the line feed, and delaying the print enable and print head movement signals during a time interval sufficient to allow for the color select solenoid to move the ribbon to the opposite color position at which time the characters of the opposite color are printed.

Abstract: Apparatus for use in a dot-matrix type impact printer for printing each line of characters and/or graphic data in a selective one of a plurality of character fonts and/or formats. In one preferred embodiment, a manual selection is made corresponding to either a normal or compressed spacing between adjacent dot columns by selection of a registration array from a group of such arrays. Dual-channel reading means cooperate with the registration arrays for determining the position of a print head as it moves across a print line and for enabling a plurality of print wires to be selectively impacted against the paper document whenever the print head is in proper registration as determined by the selected array. Spacing between registration slits of each array is uniform but is different as between arrays. The selected array may be changed either manually or remotely. Upon completion of the printing of a line, control logic means returns the printer to a "selected" format.

Abstract: An incremental impact printer of the dot matrix type. Binary words representative of data to be printed along a line of print may be accepted from either the printer keyboard or the output of a computer or other source. The printer electronics provides for either a single character or a burst of characters to be substantially instantaneously printed upon receipt. The print head is always moved to the right of the last character printed to facilitate observation of that character. The next character is printed by first moving the print head to the left of the last character printed and then abruptly reversing the print head to print one or a burst of characters "on the fly". A novel registration system serves the dual function of accurately locating the proper position for a character to be printed and determining the direction of movement of the print head at any given instant.

Abstract: A non-linear spring design for use in a high speed solenoid assembly especially adapted for use in impact printers of the dot matrix type. The solenoid coil--when energized--drives the solenoid armature and a print wire connected thereto for impact against an inked ribbon and a paper document to form a dot upon the paper document. The armature is initially driven against an initially "weak" spring biasing force of a large beam-radius spring member to facilitate rapid acceleration to impact velocity. The radial beam length of the spring member is continually shortened as the armature is displaced in the activated direction by contact at continuously varying support points on the armature head or flux ring, whereby the normally linear spring develops more force in a non-linear manner for the same displacement.

Abstract: The print head in a high-speed printer of the dot matrix type is provided with a bearing comprising an element fixedly attached to the front wall of a plastic block. The element is made of a material substantially harder than plastic, such as metal or a jewel. Guide passages extending through the element are aligned with similar guide passages in the plastic block and are axially directed towards a paper document. The forward end of the print head is provided with slots for receiving the plastic block which may be releaseably secured into position by means of a substantially U-shaped compliant brad, greatly simplifying both assembly and disassembly thereof.

Abstract: A print head for impact printers of the dot matrix type comprising a hollow die cast housing having solenoids mounted upon a rear wall thereof and having print wires driven thereby and extending through the rear wall and hollow housing toward the forward end. A plastic bearing is releasably mounted in the forward wall and serves as a low friction bearing for the reciprocating print wires and to prevent abrasive wear of the print wires when in the retracted position. The guide means mounted within the housing and intermediate the forward and rearward ends thereof support guide tubes for maintaining relative positioning of the print wires as well as maintaining their desired natural curvature.The plastic bearing is formed of a plastic material for significantly increasing operating life and which is compliant to attenuate a significant amount of side loading due to impact. The plastic bearings are admixed with additives to make the bearings self lubricating.

Abstract: 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.

Abstract: A clutch assembly which provides selective output drive especially adapted for use in incrementally driving a platen and tape reader mechanism for use in printers. An output gear is freewheelingly mounted upon the clutch assembly driven shaft and is mechanically linked to a free wheeling cam through a helical spring wound tightly about the driven shaft. The free wheeling cam is provided with at least one notch for selective engagement by a pivotally mounted solenoid actuated latch. When the latch is disengaged from the free wheeling cam, the spring is rotated by the driven shaft and imparts its rotation to both the output gear and the cam. Upon actuation of the solenoid, the latch member engages the free wheeling cam member to restrain it from rotation, causing the helical spring to unwrap itself (i.e., loosen) about the shaft and stop the output gear from rotating.

Abstract: A thermal print head assembly preferably for use with temperature sensitive impression material in a dot-matrix line printer includes a housing having a plurality of electrically actuatable means for impinging upon the impression material; means for guiding each of the plurality of impinging means to form a straight line at the housing front end and adjacent the impression material; and electrical means positioned within the housing for heating the impinging means without interfering with their movement through the frong housing end and being insulated from the housing to prevent excessive heating thereof. In a preferred embodiment, the electrical heating means is energized simultaneously with the motor of the line printer to maintain the forward ends of the impinging means at a temperature of the order of 300.degree.F. to allow printing on thermally activated paper.

Abstract: 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.