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Low Cost Thermal Printer Including a Semiconductor Print Head

IP.com Disclosure Number: IPCOM000081172D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 4 page(s) / 86K

Publishing Venue

IBM

Related People

Andrews, LP: AUTHOR [+4]

Abstract

This is a low-cost, high-speed input/output thermal printer that eliminates requirements for a horizontal carriage and/or print head traversing. The printer includes a semiconductor thermal print head chip adapted to operate directly off an AC line voltage, eliminating the need for a high-current, low-voltage DC power supply.

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Low Cost Thermal Printer Including a Semiconductor Print Head

This is a low-cost, high-speed input/output thermal printer that eliminates requirements for a horizontal carriage and/or print head traversing. The printer includes a semiconductor thermal print head chip adapted to operate directly off an AC line voltage, eliminating the need for a high-current, low-voltage DC power supply.

In Fig. 1, an acoustic coupler 1 transduces acoustic energy produced by a telephone handset into electrical signals, which are reinforced by a linear amplifier 2. The acoustic signals are either of two tones within the bandpass characteristic of a telephone system. One tone is used as a "mark". The other tone is used as a "space" signal. A demodulator 3 recovers sampling time from line A. The demodulator also recovers the data which is transmitted to a serial-to- parallel converter 4. Data bits are shifted and sampled by a control signal L. The serial data is formed into a character set which is stored by character in a data store 5. The data store consists of two buffers, each of which can store one line of print data, e.g., 80 characters. One printable character is transmitted to the data store by control signal M.

The data store can also provide character data to the parallel-to-serial converter 6 for transmission from the terminal by a modulator 7, linear amplifier 8 and acoustical coupler 9. Transmission of data from the data store is by control signal N.

Control signal N is also utilized to transmit data to the print buffer 10 by printable character. Control signal 0 transmits this data to read-only store (ROS) 11 which stores the bit pattern for a printable character. The printable bit pattern from ROS 11 is transmitted to the print head 12 by control signal P. Control signal Q enables the print head to perform an energy conversion function for printing.

A keyboard 13 permits the entry of data to the printer. A code converter 14 translates the keyboard to A:SC II code where the keyboard generates other than nonimpact terminal codes. A buffer 15 performs two functions. A character is stored while awaiting transmission to the data store 5 on control signal N. Timing sequences in control and timing unit 17 may be utilized in the nonimpact terminal, as a result of depressing function keys on the keyboard.

A power supply 18 provides all direct current for the terminal. Energy for printing is obtained directly from the AC power supply with-out conversion. A paper control 16 advances the paper a row at a time under the control of signal
T.

Fig. 2 shows a semiconductor print head chip. An AC voltage is supplied to a series of integrated circuits 22 through conductors 24. A ground wire 26 is also connected to the circuits. Data signals are provided to each chip by lines 28, each circuit receiving a discrete set of signals. Fig. 2 has been simplified to show data signals to only a portion of the circuits.

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One useful integrated circuit in...