Abstract: An inrush circuit for electronic devices is particularly useful for point-of-sale printers. The circuit applies an active feedback-controlled voltage ramp to a bulk capacitor by means of a P-channel field effect transistor that is operated linearly after a controlled delay for contact bounce.

Abstract: An inrush circuit for electronic devices is particularly useful for point-of-sale printers. The circuit applies an active feedback-controlled voltage ramp to a bulk capacitor by means of a P-channel field effect transistor that is operated linearly after a controlled delay for contact bounce.

Abstract: The present invention features a check-reading and check-validation machine having a programmed microprocessor, a photo-sensor, a magnetizing unit, a magnetic head reader, feed rollers and a stepper motor drive for rotatively driving the feed rollers. The machine may be a sub-unit of a printer. A check is introduced to the nip of the feed rollers. The photo-sensor detects the presence of the check and activates the stepper motor drive. The stepper motor drive then causes the feed rollers to rotate, drawing the check into the reading and validating machine. The microprocessor instructs the stepper motor to feed and discharge the check into and out of the machine, according to a specialized program. The microprocessor program initially instructs the stepper motor to rotate the feed rollers for forward drive, utilizing half-step pulsing.

Abstract: A security system for an unattended printing mechanism, such as that found in an automatic teller machine. The security system has a programmable microprocessor which sends data to a journal printer and actuates a journal motor that controls the rotation of the paper take-up drum. A timing disk is rotationally attached to the take-up drum. A sensor mounted adjacent the timing disk senses the rotation of the timing disk and the rotation of the take-up drum. As the timing disk rotates, the sensor generates alternating high and low signals. The sensor signals are fed to the microprocessor, which assesses the number of high/low signals, and the amount of paper being fed to the take-up roll. When it does not see a proper number of high-to-low transitions for a given amount of journal motor rotation, the microprocessor provides a signal that a jam has occurred in the printing system. The microprocessor continually monitors the sensor signals.

Abstract: This invention features a sensing system and a method for dispensing financial and retail receipts from a receipt-printing machine. The sensing system of this invention can use any one of a myriad of typical supply rolls having a media strip (usually paper) that has black marks periodically located at given intervals along its edge. The sensing system usually has a light-emitting diode (LED) and a photo-transistor. The light from the LED is directed on the supply roll, where, as the paper is advanced, it is reflected to the photo-transistor. When a black mark comes into the range of the LED, the light from the LED is absorbed and not reflected to the photo-transistor. The printing machine then stops advancing the paper, and cuts it to form a receipt of adequate length. The invention utilizes a microprocessor that has a pulse width modulator (PWM) for providing a square wave output to a digital-to-analog (D/A) converter. A program of the microprocessor controls the frequency and the duty cycle of the PWM.

Abstract: A connector for enabling a user to selectively couple one of at least a first printhead having a connection member or a second printhead having a set of connection members to a circuit. The circuit comprises first contact means for connecting the first printhead to the circuit and second contact means for connecting the second printhead to the circuit. The connector comprises a body having a first slot for receiving the connection member. The body further comprises a second slot and a third slot for receiving the set of connection members. A first plurality of male conductors is associated with the first slot in order to couple the first printhead to the first contact means of the circuit when the connection member is inserted into the first slot. A second plurality of male conductors is associated with the second and third slots in order to couple the second printhead to the second contact means of the circuit when the set of connection members are inserted into the second and third slots, respectively.

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 print head is secured to a print head carriage and movable along guide rails in printing operation. The carriage includes bearings engaging the guide rails which are secured to the frame of the printer. The print head carriage is made of conductive material to enable bonding of the print head through the carriage and the bearings and along the guide rails to the ground potential of the printer.

Abstract: A digital motor control system includes a flip-flop latch for receiving motor circuit drive data from a microprocessor, a counter for counting to a predetermined value representing the total duration of a motor drive pulse, a comparator for comparing the incrementing counter value with the motor circuit drive data stored in the latch to provide a pulse width modulated signal, delay circuitry for preventing overlapping of motor brake and motor drive signals, a drive gate controlled in part by said pulse width modulated signal for applying a drive signal for motor control, and a brake gate for applying a brake signal for motor control.

Abstract: A protective member in the form of an opaque brush operates as a non-reflective shield to an optical sensor while protecting such sensor against ambient light. The brush also provides for removal of contamination from the surface of the optical sensor as a slip or like document is inserted along a guide by causing the brush to swing across such surface.

Abstract: A dot matrix print head energy control circuit (commonly known as voltage source compensation) utilizes two pulse width modulator circuits (one for receipt printing and one for forms printing). The control circuit also comprises control circuitry and a data latch, the circuitry including RC networks and comparators responsive to outputs of the data latch. A FORMS signal, when inactive and utilizing a source or applied voltage of 24 volts, sets or selects the RC network for receipt printing having an energizing pulse duration of approximately 340 microseconds, and the FORMS signal when active sets or selects the RC network for forms printing having an energizing pulse duration of approximately 380 microseconds. A source or applied voltage of 28 volts sets pulse durations of approximately 300 and 340 microseconds for receipt and forms printing, respectively.

Abstract: A speed control circuit for a motor is responsive to variations in motor supply voltage and torque wherein a digital output indication of the actual speed of the motor is generated. The digital output is converted to an analog value and applied to a comparator which also receives the output voltage of a ramp circuit based on the motor supply voltage. The output of the comparator controls the width of the motor voltage pulses applied from a power amplifier to the motor in which the voltage pulses applied have proportionally larger width for a smaller level of motor supply voltages or decrease in the amount of motor shaft speed and proportionally narrow width pulses for increased levels of motor supply voltage or an increase in the amount of motor shaft speed. A one-shot network is provided for motor stall protection.

Abstract: An automatic ambient light compensating circuit for use in conjunction with a light sensing device to render the light sensing device insensitive to variations in ambient light conditions and which is particularly adapted for use with reflective sensor systems. An optical sensor, including a source of light and a first photodetector, is disposed to detect the presence of an object in proximity thereto. The optical sensor provides an output signal which is a function of the amount of light received by the first photodetector and includes light from the source of light and ambient light. The output signal of the optical sensor is provided as an input to a signal level detection means. A second photodetector responsive only to ambient light is operatively connected in parallel with the output of the optical sensor to the level detection means to compensate the output signal of the optical sensor for ambient light conditions.