Electronic page printer

Claim 2

An electronic page printer for printing on a sheet of recording medium, comprising: a. an electronic thermal printhead, said thermal printhead having a support chip and a character matrix of semiconductor elements mounted on said support chip in thermally separated relationship for printing characters on the sheet of recording medium, b. stationary means for supporting the sheet of recording medium in front of the printing surface of the electronic printhead, c. means for moving said electronic printhead to a plurality of printing positions across the width of said sheet of recording medium, and d. engagement means for moving said sheet of recording medium into engagement with said electronic printhead, said engagement means including a moveable member having a flat resilient pressure pad for moving a selected portion of the sheet of recording medium into contact with the said electronic printhead, said pressure pad comprising a thin, hard metal plate connected to said moveable member by a resilient block, for providing uniform contact of said printhead against said recording medium.

Claim 3

The combination according to claim 1 wherein the means for moving the electronic printhead and the pressure pad across the width of the sheet of the recording medium comprises a cable system connected both to the printhead and to the pressure pad.

Claim 4

The combination according to claim 2 wherein the cable system is driven by a stepping motor which operates through the cable system to step the electronic printhead and pressure pad into alignment with each printing position across the width of the sheet of recording medium.

Claim 5

The combination according to claim 3 wherein the cable system includes a drum driven by the stepping motor, a length of cable wound helically around the drum for supplying cable to and for accumulating cable from the cable system.

Claim 6

The combination according to claim 1 further including a pair of rollers positioned in engagement with the edges of the sheet of recording medium at the ends of the path of travel of the electronic printhead and means for selectively rotating the rollers a predetermined amount to effect line feeding for the sheet of recording medium.

Claim 7

The combination according to claim 5 wherein the means for rotating the rollers comprises a stepping motor.

Claim 8

The combination according to claim 6 further including a stationary recording medium guide member extending between the rollers and having a curved recording medium supporting surface.

Claim 9

The combination according to claim 7 further including a shaft extending from the stepping motor and a spring connected to the shaft for opposing movement of the electronic printhead across the width of the sheet of recording medium and for returning the printhead upon de-energization of the stepping motor.

Claim 10

The combination according to claim 2 further comprising: e. circuit means diffused into each of the semiconductor elements, including a resistive heating element and switch means for controlling current flow through the resistive hEating element, f. an integrated circuit chip mounted on the support chip adjacent the matrix semiconductor elements, the integrated circuit comprising a buffer stage for each semiconductor element the output of which is coupled to drive the base of the transistor switch means of the respective semiconductor elements, g. character generation means comprised of MOS transistors for decoding parallel binary character data and driving the buffer stages in a combination to graphically produce the character by heated elements of the matrix, at least a plurality of the MOS transistors being formed on a monolithac semiconductor chip, and h. supply voltage means for supplying power to the buffer stages and circuit means including means for sensing the temperature of the matrix and adjusting the supply voltage to a level such as to heat the selected mesas to a preselected temperature range.