Abstract: A linear motor for a printer has stator teeth which are protected from dust and debris generated when the printing mechanism strikes the recording paper by a downward extension of the stator teeth, by a horizontal extension of the stator teeth, or by a horizontal extension of stator teeth which face away from the printing platen. The translating member of the motor to which the printing mechanism is attached has pole teeth spaced from the stator by mechanical rollers. The motor force acts close to the center of gravity of the moving members to reduce mechanical vibrations.

Abstract: An arrangement for the drive of a printer carriage in teletypewriters or data printers in which pliable drawing means secured to the printer carriage is simultaneously driven by two drive motors. The drive motors are of identical design and cooperate with drive guide rollers arranged exteriorly of the printing area. Stepping motors preferably are employed as the drive motors and arranged with a displacement by half a step and can be alternately driven, so that one of the two stepping motors always functions in optimum torque range.

Abstract: An arrangement for driving the printing head along a printing line of a recording medium comprises a reversible direct-current electric motor which is coupled to the head for moving the latter forwards and backwards along the printing line. The head prints only during the forwards movement and during this movement the motor is supplied with a first voltage which causes the forwards movement of the head at a first substantially constant velocity. After the printing of a last character the head is moved away from the recording medium by an electromagnet and the motor is supplied with a second voltage which causes the backwards movement of the head at a second substantially constant velocity, greater than the first velocity. During the backwards movement of the head two rollers advance the recording medium and held it tensioned in correspondence with the printing line.

Abstract: An electric typewriter includes a RAM memory for storing selected characters to be printed and for storing data relating to the present escapement position and future escapement destination of a printing head of the typewriter. A control unit operates a printer to print the stored characters in the memory unit and, when a power interrupt occurs and power is subsequently restored, the control unit accesses particular position data in the memory in accordance with the angular position of a print shaft of the typewriter at the time of the power interrupt. The accessed data is employed to define a proper return escapement position for the printing head of the typewriter.

Abstract: 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.

Abstract: A serial printer comprises a carriage 1 movable along a printing line by a motor MC with a feedback transducer FBC signalling increments of carriage advance. A daisy wheel 2 carries characters to be printed and is rotated by a stepping motor MS with a feedback transducer FBS. In order to maximize printing speed without complex control of the carriage speed a control unit signals when the carriage 1 reaches each printing point in response to feedback pulses from FBC, whether fixed or proportional spacing is used. If the motor MS has by then completed character selection, as determined by counting feedback pulses from FBS, the carriage is not stopped and printing takes place on-the-fly. If character selection has not been completed, the carriage is stopped and printing is effected when character selection is completed.

Abstract: A high-speed printer includes a standard printing element, such as a daisy wheel, a paper feed mechanism and a ribbon feed mechanism. All of these various devices are controlled by a single linear actuator which comprises an elongated cylindrical magnet, C-shaped in cross-section, through which a ferrous core axially extends. A plurality of separate armatures envelope the core in the air gap between the magnet and core and are adapted to move linearly upon application thereto of a control current. The armatures control, respectively, the movement of the carriage containing the printer element, the rotation of the printer element, the advancement of the paper feed mechanism and the incremental positioning in both directions of the ink ribbon.

Abstract: A counterbalanced bidirectional drive for a hammer bank shuttle assembly within a line printer utilizes a band formed into an endless loop extending around and between an opposite pair of rotatable pulleys on opposite sides of the pulleys. A hammer bank-carrying shuttle assembly is coupled to a portion of the band between the pulleys on one side of the pulleys and is counterbalanced by an elongated bar of similar mass coupled to a portion of the band between the pulleys on the opposite side of the pulleys from the shuttle assembly. A DC motor coupled to one of the pulleys is alternately energized in opposite senses so as to bidirectionally drive the shuttle assembly along a linear path between opposite limits defined by resilient members impacted by an element mounted on the counterbalancing bar.

Abstract: A method of, and a system for, controlling a constant current hammer in a carrier type daisy wheel printer. A logic table is utilized and first addressed with a carrier velocity code corresponding to character selection time. The table output is a sync point for determining hammer turn on time. The table is next addressed with a combination code made up of the velocity code and a code corresponding to the desired impact force. The table output this time is the actual turn on time for the hammer from the sync point. The on time of the hammer is then controlled by the desired impact force code. This code is also utilized to control the beginning of selection for the next character.

Abstract: The intermittent movement of the printer's carriage and "daisy"-type print wheel is controlled by a relatively simple, reliable digital control system. The difference between the desired velocity and the actual velocity of each member is measured digitally. This difference constitutes an error signal which is used to retrieve stored values of acceleration or deceleration corresponding to various values of the error signal. These values are used to develop a corresponding electrical signal which is used to accelerate or decelerate the member to reach the desired velocity. A relatively simple circuit is provided for reliably returning the carriage or print wheel to a desired position after overshooting the position, despite a relatively large amount of overshoot. Simple, low-power-consumption holding or drive circuits utilizing pulsed voltages are provided for the stepping motors used for ribbon feed and line feed, and for the solenoids used for ribbon shift, print wheel shift and print hammer energization.

Abstract: An improved matrix printer is described employing a high order, single track incremental position encoder to provide a plurality of electrical reference signals representative of predetermined print positions along a platen and for locating matrix columns at the predetermined print positions. An electronic circuit is provided for varying the predetermined print positions at which the matrix columns can be located.

Abstract: In a printer having a print head assemblage longitudinally moving along a path parallel to a record medium, a portion of the print head assemblage is controlled to strike the record medium at a desired point by measuring the time required for sonic pulses generated in a rod at the position of the print head assemblage to arrive at a sensor, such time being a function of the distance from the print head assemblage to the sensor. A representation of this time is compared against a similar representation of a time associated with the position of the desired point and upon equality the portion of the print head assemblage is driven toward the record medium.

Abstract: A detection means is provided for generating an analog signal in response to a rotation angle of a servomotor which drives a carriage in a printer. A servomotor drive circuit is responsive to a print command from an input means and the analog signal from the detection means, whereby the carriage is driven to travel forward upon receipt of the print command and to stop upon receipt of a print termination signal. The carriage is then held stationary at a predetermined position suitable for the next character to be printed as determined by the rotation angle of the servomotor which is fed back to the servomotor drive circuit.

Abstract: An alternating current coupled dot column sensing circuit provides delayed dot position signals for control logic of a matrix printer to actuate the printing elements at the proper dot column positions in bi-directional printing. A sensor recognizes edges of slots in a timing strip across the printer and also recognizes end or home positions of the strip for use in such printing.

Abstract: By utilizing as the driving elements for paper positioning and printing head positioning two solenoids, only, with appropriate electrical and mechanical timing control apparatus to assure synchronization of printing and related functions a low cost, portable, low weight, low-power-consumption teletypewriter can be realized.

Abstract: A system of controlling the operation of a matrix printer wherein printing is performed in each direction of travel of a printing element carriage. A printer control large scale integrated device is combined with a programmable character memory device and associated circuits for responding to character code data and to the position of the printing carriage and the direction of travel thereof. Code data is input in character by character format and, by means of counters and latching devices, the pulses or signals are sent to the respective printing elements for actuation thereof for printing the dots of a matrix character.

Abstract: An electronic control circuit is designed for use with a high speed printer having a character generator which is coupled to a print head. The print head is laterally displaced along a print line by a stepper motor and forms characters from a plurality of columns of dots as the print head moves. The electronic control circuit includes an encoder which is coupled to the shaft of the stepper motor to generate count up pulses when the stepper motor displaces the print head in a first direction and count down pulses when the stepper motor displaces the print head in a second direction. The count up and count down pulses permit the control circuit to continuously define the present print head position. A random access memory receives printable characters during a load cycle and reads out printable characters to the character generator during a print cycle.

Abstract: A high-speed printer in which the carriage carrying a print wheel is coupled to a servo controlled driving motor having intermittent motion. The motor drives a helically grooved pulley, which has attached to it left and right cable segments. The other ends of the cable segments are attached to the movable carriage. A cable preload spring and friction pulley snubber combination maintains cable tension relatively constant. The snubber provides a tight cable system during normal carriage acceleration and deceleration. The preload spring allows for tension correction when the cable suffers from long-term stretching due to constructional stretching, that is, the normal tendency of wound cables to stretch due to seating of individual wires in the strand.

Abstract: A printer for printing characters on paper supported adjacent a path along which a print head can be traversed. Two servo-motors are mounted adjacent the path and each connected to the head by a toothed belt. Control means connects the servo-motors in one of two modes: in the first, one servo-motor is energized to pull the head on a printing traverse while the other servo-motor is connected as a dynamic brake; and in the other, the other servo-motor is energized to pull the head on a fly-back traverse while the other servo-motor idles. To stop the head either in a printing traverse or at the end of a fly-back traverse, the mode of connection of the control means is reversed.

Abstract: A printer head is mounted on a carriage which is driven to travel in the row direction at a predetermined constant speed. A pulse generation device is provided for developing a pulse signal in response to the travel of the carriage in order to determine print width. A detection device develops a detection signal when the carriage reaches the first print position to initiate printing of the first character. The detection signal is applied to a counter which counts a time interval from a time at which the last pulse is developed from the pulse generation device to a time at which the detection signal is developed. The following character printing is effected each time the pulse generation device develops a predetermined number of pulses indicative of one character width or print pitch and the time interval determined by the counter has passed from the time at which the last pulse of the predetermined number is developed.

Abstract: A printer including a print head adapted for reciprocal displacement across a print tape for effecting printing on the tape in at least one direction of the displacement is provided. The print head is engaged with a timing belt operatively coupled to a drive assembly for selectively advancing the belt in one direction either intermittently or continuously. A direction shift assembly is provided for selectively operatively coupling the print head to the timing belt at either of two locations for selectively displacing the print head in opposed directions. The printer also includes a clutch assembly for selectively transmitting unidirectional rotation power from a motor to the timing belt.

Abstract: Carriage space and line feed signals produced between consecutive character print signals are accumulated and logically combined to form a resultant signal rather than being executed as produced. In response to a character print signal, the carriage and line feed are moved in accordance with the resultant signal to the designated position and then the print operation is executed.

Abstract: A drive arrangement for a single element typewriter in which the element is mounted on a moving carrier, for facilitating proportional spacing incremental movements of the carrier. The carrier is bidirectionally driven by a servo motor which rotates bidirectionally in response to the output of a digital counter. The counter counts in one direction in response to input stepping pulses as well as pulses corresponding to incremental rotational movements of the drive shaft in a given direction, and counts in the other direction in response to pulses corresponding to incremental rotational movements of the drive shaft in the opposite direction. The pulses corresponding to incremental rotational movements of the drive shaft are optically derived from a rotating disk having alternating transparent and opaque radial striations. Provision is made for automatic carrier return by setting the output of the counter accordingly.

Abstract: The carrier for the print head of a printer which is to be used at different operating speeds as a display printer, as a read-only printer, or as a keyboard display printer with asynchronous character rates over a wide range, is operated by a servo motor under the control of a digital/analog converter which continually sums the outputs of an up/down counter which is incremented by incoming data and decremented by the output of a shift register advanced by the incoming data.

Abstract: Apparatus for printing characters on at least one data carrier comprising a printing head movable along the data carrier, a line advance device for feeding the data carrier substantially perpendicular to the moving direction of the printing head, an ink ribbon feed mechanism for feeding an ink ribbon in relation to the data carrier, a cut-off mechanism for cutting off the data carrier, and a shaft rotatable less than 360.degree. in one direction by a reversible motor from a home position to an end position determined by the selected operation cycle and thereafter back to the home position by reversing the direction of rotation of the shaft. The reversal of the shaft is performed at different times during subsequent operation cycles to permit gears and cams on the shaft to move the printing head to positions determined by the number of characters to be printed on the data carrier, actuation of the line advance device, and actuation of the ink ribbon feed mechanism or cut-off mechanism.

Abstract: A serial impact printing element is mounted on the slider of a high performance linear stepper motor. The slider moves through the stator-to-stator air gap of the linear motor stator comprising an active stator portion having windings associated therewith and a passive stator portion without windings. In order to achieve high performance of the motor, the slider is relatively short as compared with the stator, and longitudinal flux leakage through and the weight of the slider are minimized by the use of nonmagnetic discontinuities therein. The impact printing element includes a wheel having a plurality of circumferentially spaced character elements which are rotated to the printing position by means of a rotary stepper motor.

Abstract: A shifting arrangement is provided for the exact space positioning of a writing carriage for office, teletype or data typewriters in which the writing carriage is moved step-by-step alongside of a record structure in accordance with a predetermined character positioning pattern. The writing carriage is driven by a stepping motor which has a rotary field. A specific number of angle positions of the stepping motor field serve as basic advance positions of the stepping motor in order to compensate for the load angle of the stepping motor during running of the writing carriage. Such basic advance positions are assigned to each character positioning point of the positioning pattern. An electronic device is provided for triggering the rotary field of the stepping motor and automatically adjusting this rotary field to the corresponding basic advance position during running and setting the field to a rest position during stopping of the stepping motor in order to correct for the stepping motor load angle.

Abstract: A driving mechanism for the carriage of a printer, having a motor with a driving pulley thereon, which has attached to it the ends of left and right cables, each of which is folded at its respective center. The folded portions of the cables are wrapped on a pair of pulleys mounted on the carriage.

Abstract: To more fully utilize the surface area of a typewriter ribbon in a cartridge ribbon receptacle, the cartridge locating plate supporting the receptacle is caused to oscillate with respect to the print head assembly. The ribbon cartridge assembly is a part of a print head and ribbon carrier that is positionable along a line of print by a drive motor through a belt drive engaging a drive pulley rotatably mounted to the carrier. Mounted to rotate with the drive pulley is a cam that engages a cam follower also mounted to the head and ribbon carrier. An upstop forms a part of the cam follower and engages the cartridge locating plate. With the cam follower driven by the cam, an oscillating motion is imparted to the upstop with reference to the head and ribbon carrier which motion is then imparted to the cartridge locating plate. Also fastened to the head and ribbon carrier is a solenoid that when energized spring biases the cartridge locating plate through a leaf spring attached to the plate.

Abstract: In a serial printer a movable type character element such as a ball, disc or the like is rotated to present different type characters to the print position. The carrier for the type element is moved along the print line at a predetermined maximum velocity so long as it is possible to move the type element to the next character in time required to move the carrier from one print position to the next. If the type character set-up time is greater, the carrier is run at a slower speed and is then returned to the predetermined velocity for printing.