Printer power supply

• US 5,595,446 A
• Filed: 10/12/1994
• Issued: 01/21/1997
• Est. Priority Date: 10/12/1994
• Status: Expired due to Term

• Current Assignee: Printronix
• Original Assignee: Printronix
• Inventors: Schumaker, Richard E., Barrus, Gordon
• Primary Examiner(s): WIECKING, DAVID
• Application Number:
  US08/321,564
• Time in Patent Office: 832 Days
• Field of Search: 400/124.03, 400/124.13, 400/124 TC, 400/54, 400/719
• US Class Current: 400/124.13
• CPC Class Codes: B41J 9/36 in which mechanical power is applied under electromagnetic control

Abstract

A printer is disclosed of the dot matrix type having a series of hammers with pins that print upon an underlying media, and which are released from magnetic retention by reversing the polarity of a permanent magnet and having electro-mechanical drive circuits and logic circuits. A power supply supplies an output of a voltage level for driving the electro-mechanical circuits connected to a ribbon drive, platen drive, paper feed, shuttle motor, and fans at a given voltage and the hammers at a different voltage. A thermal sensor is connected to a heat sink of the power supply, and to the printer controller to change the rate of printing when pre-established temperatures are sensed.

Claims

1. A printer for dot matrix printing on a media comprising:

a hammerbank having a plurality of hammers which are retained by permanent magnet means;

means for releasing said hammers;

a ribbon drive comprising first and second motors for driving a ribbon by said hammers for imprinting dots on the media by said hammers impinging the ribbon;

means for feeding media over said hammers in said hammerbank;

platen means for supporting said media against which said hammers can impact;

a shuttle supporting said hammerbank for reciprocating shuttle movement across said media;

fans for cooling said printer;

a controller for controlling said printer movement;

a power supply connected to said controller for providing an output o fpower to said printer for driving the ribbon and fans, an for driving the hammers of said hammerback at a different voltage from said ribbon drive and fans, and an output for providing power to the controller of said printer;

thermal sensing means connected to said power supply for sensing its temperature; and

,

means to signal said controller of a pre-established temperature of said power supply sensed by said thermal sensing means.

2. The printer as claimed in claim 1 wherein:

said thermal sensing means comprises a bi-metallic switch.

3. The printer as claimed in claim 1 wherein:

said thermal sensing means comprises a thermistor connected to a comparitor.

4. The printer as claimed in claim 2 wherein:

said thermal sensing means is connected to a heat sink of said power supply.

5. The printer as claimed in claim 1 wherein said permanent magnet means for retaining said hammers comprise:

at least one pole piece in a magnetic circuit provided by said permanent magnet means;

coil means in association with said pole piece; and

,

means for electrically actuating said coil means to overcome the magnetism retaining said hammers by said at least one pole piece.

6. The printer as claimed in claim 5 wherein:

said hammers comprise a hammer having a pin at one end thereof which provides the dot of a dot matrix printing by the printer.