Abstract: A mounting bed integral with a hammer bank is disposed parallel to a counter balancer composed of a counter balancer constituting member and a yoke. The mounting bed and the yoke are provided with solenoid coils opposed to a permanent magnet provided on the frame, and a pair of bearings are arranged between the mounting bed and the counter balancer constituting member. A position sensor for the mounting bed and the counter balancer is provided. A controller is provided to control a current and direction of the solenoid coil by a detection signal from the position sensor. The mounting bed integral with the hammer bank and the counter balancer are shuttle-operated in opposite directions by the controller.

Abstract: A printing machine wherein printing onto a substrate is effected by a first movement of a print head (1) downwardly into contact with the substrate and then by a second movement over the surface of the substrate while thermal printing elements within the print head (1) are selectively energized. The first movement is controlled by downward movement of a pair of rollers (6,7) operated by synchronized angular movement of a pair of eccentric shafts (8,9) one of which is freely mounted within each roller (6,7). The first and second movements are driven by a first and second stepper motor respectively. The rollers may be coupled by drive belts (4,5).

Abstract: A shuttle printer having a print shuttle unit capable of reciprocating with a print head mounted thereon, and a balance shuttle unit capable of reciprocating to generate counterforce to momentum of the print shuttle unit. The shuttle printer includes a device for driving the print shuttle unit to reciprocate, and a device for driving the balance shuttle unit to reciprocate. The shuttle printer further includes a device for detecting the position of the print shuttle unit, and a device for synchronously controlling the two driving devices in response to a result of detection by the print shuttle unit position detecting device.

Abstract: A shuttle apparatus for a printer having a print shuttle unit driven to reciprocate. The print shuttle unit includes a print shuttle provided with a print head and movable along a guide device. A row of permanent magnets are attached to the print shuttle, and a row of electromagnetic coils are secured to a stationary member so as to face the permanent magnets across a gap. The coils and the permanent magnets constitute a linear motor for reciprocating the print shuttle unit along the guide device. A balance shuttle unit having approximately the same weight as that of the print shuttle unit is disposed so that the center of gravity of the balance shuttle unit travels on a line approximately the same as the line of travel of the center of gravity of the print shuttle unit. The balance shuttle unit is driven to reciprocate in linked relation to the print shuttle unit in parallel but reverse in direction to the print shuttle unit.

Abstract: Printing control includes determining printing dot density of print data to be supplied to a printing head, averaging the printing dot density during a predetermined period of time based on the printing dot density determined, selecting a printing speed in response to the average value of printing dot density, and controlling printing to print at the selected printing speed.

Abstract: A control device for a matrix printer in which the mechanical printing elements of the matrix printer are selectively triggered by the control device a certain time before they reach the desired printing spot on the information carrier in order to compensate for the fact that the printing head will move further over a certain distance between the triggering moment and the moment that the printing element actually hits the information carrier. This distance depends on the speed of the printing element. If the print signal, however, is always generated a constant distance before the printing element reaches the desired printing spot, this signal must be delayed as a function of the speed of the printing element if the printing head is to print accurately also during its run-up and slow-down. To this end, a delay device is provided which delays the print signal for the relevant printing element by a time interval which depends on the printing head speed.

Abstract: A method for setting an apparatus, such as a printer, wherein a sensor is mounted to sense the position of a settable detection object during operation of the apparatus. The apparatus may be set as a function of the occurrence of an output from the sensor that is above or below a predetermined level at predetermined setting positions, as a function of the setting position that is close to the middle point of a range defined by adjacent positions at which the output level of the sensor rises above and falls below the predetermined level, or as a function of the position at which the highest output from the sensor is detected.

Abstract: A printing machine for printing at printing positions along a line, and for performing a positional control by linear encoder. The printing machine comprises a linear encoder memory and detecting means. The linear encoder memory has a line-shaped magnetic recording medium formed of an alloy consisting essentially of iron, chromium, cobalt, no more than 0.03 weight % of carbon, and optionally 0.05 to 3 weight % of at least one element selected from the group consisting of titanium, vanadium, molybdenum and tungsten. The linear encoder memory extends parallel along a line of printing positions. The detecting means is coupled to the magnetic recording medium and is movable relative to the magnetic recording medium. The decting means detects a magnetic record on the magnetic recording medium. The detecting means comprises a magnetic head which includes a magnetic sensor element and a supporting mount.

Abstract: In a typewriting apparatus in the invention, the carrier is driven by a stepping motor. Characters printed by this apparatus are divided into two groups, one for characters frequently used but requiring no higher printing position precision and the other for characters less frequently used but requiring higher printing position precision. Furthermore, each group can be printed in a normal printing mode or in a boldface printing mode. These four kinds of printing are executed by selecting their respective suitable pulse rates of the stepping motor.

Abstract: A device for driving optical units for scanning manuscript and provides that movement of the optical units during scanning is achieved by a first pulse motor exhibiting low-noise and high-torque characteristics within a motor speed range suitable for achieving a desired scanning travel speed. Return movement of the optical units is achieved by a second pulse motor exhibiting low-noise and high-torque characteristics within revolving a motor speed range suitable for achieving a higher desired return travel speed. Not only are the optical units moved in both directions, but also noise generated during such movement is reduced as much as possible.

Abstract: A process for controlling the operation of a printing head detects defects in the transport of the printing head along a printed line and if necessary corrects them. A control unit (24) controls a current source (16) which supplies current to a transport motor (12) which moves the printing head (10). The printing elements (14) of the printing head (10) are supplied with pulsed drive current (ID) by a driver component (18). A position indicator (20) records the distance travelled by the printing head (10) along a printed line. According to the invention, the transport time between two printing positions is monitored to detect whether a limit value (G) is exceeded. If the limit value (G) is exceeded, the drive of the printing head (10) is stopped and if necessary the printing head is moved in the opposite direction and/or at least one printing element (14, 15) is operated with less energy that that required for printing.

Abstract: A device for PWM control of the printer carriage motor (1) which has a circuit (65) for generating a first PWM pulses of 100% duty ratio, a circuit for computing second PWM pulses (31, 37, 39, 15, 17, 53, 57, 59) according to the PI control method based on the difference between the motor current speed and the predetermined standard speed, and a circuit (121) for holding the optimum integrated value for controlling the motor current speed agree with the standard speed. Until the motor current speed reaches a predetermined transfer speed slightly lower than the standard speed, the carriage motor is accelerated with the maximum acceleration according to the first PWM pulses, when the transfer speed is reached, the optimum integrated value is set as the initial integrated value of the PI control, and thereafter the speed control is carried out according to the PI control method.

Abstract: A dot line printer with a paper feed time controlling capability includes a hammer bank accommodating a plurality of print hammers, a shuttle mechanism for shuttling the hammer bank back and forth along a print line, and a sheet feeding mechanism for feeding a sheet of paper in a direction perpendicular to the direction in which the hammer bank shuttles. When a first predetermined amount of a line space feeding is to be carried out after completion of one line printing, a hammer bank reversing time is prolonged. When more than the first predetermined amount of the line space feeding but less than a second predetermined amount of line space feeding is to be carried out, it is carried out during an extended period of time including both the hammer bank reversing time and the subsequent hammer bank scanning time without prolonging the hammer bank reversing time.

Abstract: A recording method and apparatus for effecting recording on a recording medium includes elements and steps which recognize a recording width over which recording is to be effected and effecting recording on a recording medium at a movement velocity selected in conformity with the recognized recording width by first accelerating a recording unit along the conveyance path of the recording medium, then moving the recording unit along the conveyance path with a uniform velocity and then decelerating the recording unit, and by effecting recording when the recording unit moves at a constant velocity and when the recording unit is accelerating or decelerating.

Abstract: A printing apparatus includes a platen on which a printing medium is set, a carriage which is movable along the platen and having a guide for guiding the printing medium to the platen and a printing head for making a print on the printing medium which is set on the platen, a first motor for moving the carriage along the platen, a second motor for feeding the printing medium, and a controller for controlling the first motor so that the carriage is moved to a first position until a tip end of the printing medium passes between the printing head and the platen and the carriage is moved to a second position after the tip end of the printing medium passes between the printing head and the platen, where the first and second positions are mutually different positions.

Abstract: An electronic typewriter has a reduced number of electrically-powered actuators and comprises a motor powering a differential motion transmission unit having first and second output members. Transmission control means powered by a solenoid moves a slider to engage stop members selectively with the first and second output members to permit the second and first output members respectively to rotate. The first output member drives the carriage transport mechanism. The second output member drives the character carrying element and also powers function devices, namely a correction device, through a motion switching mechanism controlled by a switch control mechanism including another solenoid. The typing ribbon feed is driven by reciprocation of the slider between its two states. The motor is mounted on the frame and drives the motion transmission unit on a carriage through a belt; it also drives a line spacing mechanism through a clutch operated by a further solenoid.

Abstract: A printing controller for a serial printer, wherein a carriage having a printing head is reciprocated by a motor via transmitting a means, includes a carriage position detector for detecting the position of the carriage to produce a position detection signal; a timing signal generator for detecting the rotational position of the motor, thereby producing a timing signal synchronously with the movement of the carriage in a line direction; a synchronizing signal generator for producing a synchronizing signal per each predetermined plurality of timing signal synchronously with the timing signal, and a control circuit for producing a printing initiation signal, on the basis of the position detection signal, the timing signal and the synchronizing signal, in accordance with a first timing signal after the carriage leaves a home position and receives a first synchronizing signal.

Abstract: The print substrate support (3) and longitudinal guides (4) for a print-head slider (7) are disposed in parallel at the invention printer. A controllable paper-guide drive motor (10) is furnished for the paper guide (9; 9a) and a drive motor (11) is furnished for the print-head slider (7). In order to be able to economically produce printers for different paper widths, and in order to eliminate problems of interfering radiation, a separated space (14) is furnished at the end of the paper guide (9; 9a) or respectively, of the longitudinal guide (4). At least one control-logic printed circuit board (15), an interface printed circuit board (16), the paper-guide drive motor (10) as well as the print-head-slider drive motor (11) are disposed in the separated enclosed space (14).

Abstract: A printer which includes a position controller for moving a printing head to a predetermined initial position by driving a stepping motor during initial processing operation, and a current controller for supplying a second current to the stepping motor to spontaneously start the stepping motor. Since the stepping motor is driven by the second current which is smaller than a first current to be supplied during printing, the noise to be produced during the initial homing operation can be minimized.

Abstract: The subject invention is an optical sensor detection system for a serial printer useful for the determination of alignment and misalignment of images on a sheet of print media and the correction of misalignment. The present invention includes a photoelectric sensor mounted on the carriage of a serial type printer to locate various indicator markings.In operation the sensor detects the position of a midpoint indicator when the carriage travels from right to left, and then from left to right. The positional information is then compared with the assumed mid-carriage position of the print head based upon the time of travel, that is, the predicted position of the sensor assuming no flex in the support members of the print head and no stretch of the belt driving the print head.

Abstract: A serial color printer equipped with a cassette holder (3) that carries an ink ribbon cassette (3) dismountably on a carriage (2) of a printing head, and is tiltably mounted on said carriage (2) so that the ink ribbon may be moved in a direction vertical to said platen. The ink ribbon (7) includes a plurality of longitudinally parallel color regions, and can change the color adapted to the print line along with the movement of the cassette (3). The cassette holder (3) is connected operationally to a tilt arrangement, and the tilt arrangement is equipped with a cam mechanism (12, 15) mounted on the carriage (2), and a drive mechanism for driving said cam mechanism in conjunction with the carriage (2). The respective home positions of the carriage (2) and the cassette holder (3) are discerned by a single position sensor, and when the carriage (2) and the cassette holder (3) are in positions other than the home positions, the initial setting process of moving them to the home positions is carried out.

Abstract: A serial printer includes a reciprocably mounted carriage having a printing head, and a generally flat flexible cable extends between the carriage and a drive circuit. A generally flat flexible reinforcing plate comprising a shield electrode is disposed in superimposed relationship to the flexible cable.

Abstract: A print head carriage of an impact printer is monitored by means of a segmented timing member which is separate from but coupled to and movable in coordination with the carriage. The segmented timing member is associated with a carriage drive motor and preferably comprises a toothed wheel which is rotated by a motor drive gear also used to move the print head carriage. The teeth of the toothed wheel are monitored by an optical sensor with a resulting series of pulses being accumulated to define the rotation of the toothed wheel and thereby the movement and position of the print head carriage. A home carriage position is directly indicated via a carriage position indicating member which is operated by the print head carriage to interrupt the optical sensor of the preferred embodiment.

Abstract: A printing apparatus includes a platen on which a printing medium is set, a carriage which is movable along the platen and having a guide for guiding the printing medium to the platen and a printing head for making a print on the printing medium which is set on the platen, a first motor for moving the carriage along the platen, a second motor for feeding the printing medium, and a controller for controlling the first motor so that the carriage is moved to a first position until a tip end of the printing medium passes between the printing head and the platen and the carriage is moved to a second position after the tip end of the printing medium passes between the printing head and the platen, where the first and second positions are mutually different positions.

Abstract: A printer has a bi-directional stepper motor that drives an endless toothed belt which is secured to a print head carriage for driving the carriage back and forth across the printer along a line of printing. A timing strip is molded integral with the frame of the printer and positioned under the print head carriage. An optical sensor of the light emitting diode and phototransistor type is secured to the underside of the carriage and positioned to straddle the timing strip as the carriage is driven back and forth across the printer. The printer controller uses timing strip/sensor signals to place the print head in a home position when the printer is turned on and also when the print head has been moved from an operating position, e.g. in the case of changing a ribbon. The timing strip/sensor signals are also used to detect a carriage jam condition.

Abstract: A recording apparatus in which the movement of a recording head for recording scanning is effected includes a carriage carrying the recording head thereon, a step motor for moving the carriage, a linear encoder for detecting the amount of movement of the carriage, the linear encoder being installed over the movement range of the carriage and generating pulse signals in conformity with the amount of movement of the carriage, a controller for counting the pulse signals from the linear encoder and outputting a control signal for the starting and stoppage of the carriage in conformity with the count value, and current switch-over device for switching over and controlling an energization current supplied to the coil of the step motor in conformity with the pulse signals from the linear encoder.

Abstract: Both a test printing pattern during a forth direction printing and a test printing pattern during a back direction printing are displayed on a screen of a display apparatus. The test printing pattern is occurred at a predetermined detection position by counting a value of an up/down counter. A printing position drift between the forth direction printing and the back direction printing is shown on the screen. The optimum printing position drift having the smallest printing position drift amount is detected on the screen by the test printing patterns. A corrected result of the printing position drift is printed. A correction value of the printing position drift is renewed at an optimum value. The printing position drift in such as ruled lines is set at the minimum value. A high quality printing for a document data can be maintained and a high throughput for the document data can be obtained.

Abstract: A shuttle printer carries out printing on a printing paper when a hammer bank shuttles back and fourth. At the beginning of the hammer bank reversal at the right or left end in the hammer bank shuttling path, a braking force is exerted to a shuttle motor which drives the hammer bank and an acceleration force is exerted to the shuttle motor immediately after the hammer bank turns around. In order to set a reversing duration of the hammer bank at constant, the braking force and the acceleration force exerting durations are prolonged from a predetermined minimum to a value when the hammer bank reversing duration is shortened to an extent as desired, whereby a printing paper can be fed a predetermined amount within the hammer bank reversing duration as desired.

Abstract: A system (11) for monitoring and controlling the movement of a mass (12) along a predetermined path (14) by a motor-driven flexible member (20) is provided to modulate the motor drive output so that the actual velocity of the mass corresponds more closely to the desired target velocity profile. The system preferably employs a dual loop servo system wherein an outer servo loop uses conventional linear encoding techniques and is supplemented by an inner servo loop utilizing a sensor (27) that detects a physical characteristic of the flexible member representative of the relative velocity of the mass. Relative velocity transducers utilizing magnetic circuits and operating according to variable reluctance principles for generating relative mass velocity signals directly are disclosed.

Abstract: A method for operating a dot-matrix printer to allow printing in the accelerating and decelerating regions of the carriage traverse, which comprises the steps of: firing the wires for registration at the present position of the carriage and stepping the carriage by energization of a stepper motor driving the carriage for the period required to complete the step when accelerating the carriage or the period required to brake the carriage when decelerating the carriage. These times will decrease as the carriage accelerates to the desired velocity and will increase as the carriage decelerates from the desired velocity.

Abstract: Control parameters necessary for controlling mechanism sections of a printing apparatus are stored in a program ROM. Selection data used for selecting predetermined control parameters stored in the program ROM are stored in a non-volatile memory. When operations of the mechanism sections of the printing apparatus are selectively changed, the selection data stored in the non-volatile memory are changed in accordance with operating states of the mechanism sections. The mechanism sections of the printing apparatus can be controlled upon every change in their operations without replacement of the ROM for storing the control parameters.

Abstract: A serial impact printer comprising a support frame, a platen mounted for rotation upon the support frame, a print element having character imprinting portions disposed thereon, a print element selector for moving the print element to position a selected character imprinting portion at a printing position, a marking ribbon and a lift-off ribbon. A hammer for moving a selected character imprinting portion for deforming the platen with a printing force, and means for moving the hammer toward and away from the platen. Each ribbon is selectively positionable between the print element and the platen. A carriage mounted for reciprocating movement generally parallel to the platen supports thereon the print element, the print element selector, the marking and lift-off ribbons, means for positioning the ribbons, means for advancing the marking ribbon, the hammer, and the means for moving the hammer. A single D.C.

Abstract: A printer including a stepper motor for moving a carriage, a detector for detecting arrival of the carriage at a detection point within a range of the carriage movement, a stop for determining one end of the carriage movement range, and a first setting device operable upon power application to the printer, for activating the motor to move the carriage toward the stop until the carriage arrives at the detection point, and further activating the carriage in the same direction by a predetermined number of steps from the detection point such that the motor is activated without displacement thereof with the carriage held in abutment on the stop for at least the last one step, whereby a zero point of the carriage is established for the first time after the power application.

Abstract: A serial printer control circuit having a motor control section which includes a single CPU, and a circuit which is controlled by the single CPU so as to perform printing in a period other than a acceleration/deceleration period of a spacing motor and perform paper feed by driving/controlling a line feed motor during a deceleration period of the spacing motor.

Abstract: A printer mounted on an electronic cash register (ECR) performs printing on printing paper by moving a print head left to right and right to left, i.e. bidirectionally. The printer uses right and left reset signals to determine the print start position and printing direction of the print head, the right and left reset signals being fed alternately and regularly to the driving circuit for the print head for performing bidirectional printing, thereby assuring correct bidirectional printing. The right and left reset signals are constantly monitored. If the reset signals of the same kinds are successively detected, it is judged that trouble has occurred, hampering correct bidirectional printing, and notice is issued accordingly.

Abstract: A motion controller for the head carriage of an ink jet printer comprises a target signal generator providing constant velocity reference input to a servo loop controller. Also, two levels of current are applied to the drive motor during direction reversal, a lower one during deceleration of the carriage, and a higher one during acceleration of the carriage. The timing of the two current levels is determined by inputting a rectified velocity signal into a slope detector. A comparator converts the output of the slope detector into a binary signal for controlling the motor current level.

Abstract: A typewriter or similar machine having a platen turnable by means of a ratchet and a line spacing wheel and a carriage movable along the platen by means of a pulling means, on which a typing element or push button is disposed. In accordance with the invention a so-called lift-rotation motor is used for turning the platen, for line spacing and for moving the carriage. Its turning movement is transferred to the carriage by a pulling means. The axial movement of the motors causes the pivoting of a ratchet support on which the spacing ratchet is disposed which turns the platen by means of a toothed spacing wheel. In this way no additional motor for one of the two functions is required. The lift and rotary movement of the motor can take place temporally superimposed. In this way no time delays occur in the course of operation of the typewriter or of a printer.

Abstract: An improvement to a dot matrix printer of the shuttle variety wherein a printhead is oscillated from side to side within a printer base. The shuttle is disposed within a ballistic energy transfer device mounted for oscillating movement from side to side in the opposite direction to the instantaneous movement of the shuttle. A rebound spring is operably connected to exert a rebounding force against the shuttle to aid it in reversing direction. Also, a centering spring is operably connected for exerting a centering force against the ballistic energy transfer device. A linear motor is connected for driving the shuttle back and forth in an oscillating motion with respect to the ballistic energy transfer device. Optionally, the linear motor is connected for driving the ballistic energy transfer device back and forth in an oscillating motion with respect to the printer base. The turnaround time of the shuttle is adjusted by adjusting the span of the shuttle or the spring constant of the rebound spring.

Abstract: A control topology for a servo motor carriage drive includes a strain gauge coupling the carriage to a motor-driven belt to provide a signal representative of the flexure of the belt. A velocity signal is taken from a linear encoder on the carriage. These signals are used in inner and outer feedback loops for controlling the velocity of the carriage as it travels along a predetermined path.

Abstract: Disclosed herein is an origin indexing apparatus applicable to a printer. A moving member, such as a printing head mounted on a carriage, is moved by a stepper motor which rotates in stepwise fashion by sequentially changing excited phase by a predetermined number K. An initially set origin of such a moving member is exactly indexed or identified in a later origin indexing operation according to the relationship between the phase difference between excited phases of the stepper motor at the time of initial setting of the origin and the origin indexing operation and the number of phases K of the stepper motor. One of three positions is indexed as the origin based upon this relationship, including a center position corresponding to a subsequent specified phase appearing in the same cycle following the indexed excited phase, and positions downstream and upstream of the center position.

Abstract: In a serial printer wherein a bi-directionally operating motor drives a carriage in an oscillatory motion between two end points, an improvement for minimizing the time for direction reversal of the carriage. There is a ballistic rebound device for transferring energy of the moving carriage in one direction into a resilient member and for retransmitting energy absorbed by the resilient member back into the carriage in a direction opposite the one direction. There is also an electrically operated brake for selectively coupling the ballistic rebound device to the carriage. Sensing apparatus is provided for sensing the position of the carriage with respect to the two ends.

Abstract: In a carriage driving system of a printing apparatus, due to play between gears and elongation of a wire or belt, a positional error is produced in the stop position of a carriage when the carriage is moved in the backspacing direction. Then, in the conventional printing apparatus, the carriage is backspaced while the error is regulated every time data is inputted in the centering mode or the right margin flash mode, but this increases the number of times of movement of the carriage, and therefore extra vibration and noise are generated. Disclosed is a printing apparatus comprising a regulating means for controlling a printing means to regulate a positional deviation in response to a print start command signal in a specified mode such as a centering mode and a right margin flash mode.

Abstract: A serial printer including a print head, a carriage supporting the print head and moved by a drive motor along a line of printing, a pulse generating device for generating pulse signals corresponding to incremental distances of movement of the carriage, a time-data memory for storing time data representative of a time interval between a point of generation of each of the pulse signals, and a point at which the print head effects a printing operation, and a time-interval measuring device operable to measure the time interval according to the time data stored in the time-data memory. The time-interval measuring device generates a printing command to activate the print head upon termination of measurement of the time interval.

Abstract: A hybrid printer includes at least one impact type print head and at least one non-impact type print head, which are selectively used to print not only graphic information but also character information. For example, the impact type print head may be a type wheel print head and the non-impact type print head may be a pen print head. The print heads are selectively magnetically coupled to the carriage drive belt.

Abstract: Upon supply of electric power to a printer, a dot pulse is generated from a dot pulse generator each time a carriage driving motor rotates for a predetermined rotational angle, and thereafter, an output of a home position sensor falls when a carriage reaches its reference moving position.

Abstract: A carriage control system for a printer which effects printing by moving the carriage mounted on a print head to reduce the distance on either side of the printing area required for acceleration and deceleration. Various approaches to rapidly and accurately accelerating carriage to a selected constant speed and then decelerating the carriage from the constant speed to a stop are provided. Both open-loop and closed-loop control approaches are utilized.

Abstract: A resonant frequency reciprocating print bar drive mechanism having print bar assembly mass 12 and counterweight 13 held in spaced relationship to each other by first and second leaf springs 16 and 17, which are of equal flexural stiffness. Drive solenoid 14 is mounted between the first and second springs 16 and 17, for inducing reciprocal oscillation between print bar 12 and counterweight 13. The print bar assembly, counterweight and spring assembly is itself suspended as a single unit from perimeter frame 11 by suspension springs 15. Suspension springs 15 have a much lower spring rate than that of leaf springs 16 and 17, and, as a result, the print bar assembly 12 and counterweight 13 will reciprocally oscillate, relative to each other, at a single resonant frequency.

Abstract: In a printer in which an elongated shuttle is driven in reciprocating fashion across a print paper with hammers mounted along the length of the shuttle being selectively fired to print dots on the paper, a timing system provides hammer fire pulses denoting the positions of the shuttle at which hammer firing should be initiated to print in the proper dot positions. Proper timing is maintained so as to allow for printing during acceleration and deceleration as well as during constant velocity movement of the shuttle by determining the average shuttle velocity between each successive pair of fence post pulses generated by a shuttle-coupled encoder. The average velocities are represented by the time lapses between occurrence of the pairs of fence post pulses which are measured and stored during each startup of the printer as well as each time the nominal operating shuttle velocity is changed as part of a change in printer operation.

Abstract: A wire fire control mechanism is provided for use in a wire matrix printer for controlling the firing of the print wires as the printhead moves across a print receiving medium. This wire fire control mechanism enables printing to be accomplished for a wide range of different printhead speeds. It also enables printing to be accomplished while the printhead is accelerating or decelerating. It further enables dots to be printed at positions which are not dependent on or limited to the fixed points defined by the emitter signals which are used to keep track of the position of the printhead as it moves across the print receiving medium. In a representative embodiment, the wire fire control mechanism includes emitter means for sensing movement of the printhead and producing emitter signals which define fixed points across the print receiving medium.

Abstract: A serial dot matrix printer is provided with a slit encoder and an optical sensor opposed to the slit encoder. In the slit encoder, firing signal slits each having a fixed width are provided at a fixed pitch, and block signal slits each having a width smaller than that of each firing signal slit are provided in every block composed of a plurality of the firing signal slits. As a carriage moves, the optical sensor moves along the slit encoder to produce a signal at every slit. The signal from the optical sensor is applied to a first control device having a block detector and a firing timing unit. The block detector receives the signal from the optical sensor, measures the passing time between every slit, and detects a block signal according to a difference in passing time between the slits.