Method and apparatus for operating a printer
AssigneeCentronics Data Computer Corp.
InventorTimothy C. Morse
Life of this patent
Estimating the term…
Abstract
Method and apparatus for operating a printer to control acceptance of data from an external source and to execute the operations associated with printing. The electronics comprises a microprocessor based control system in which both the program steps and the data to be printed are stored in the microprocessor memory and wherein the microprocessor accepts incoming data and processes such data in accordance with foreground and background programs, respectively, and wherein the system is provided with interrupt capabilities for jumping from one program to the other upon the occurence of predetermined criteria. A number of protective techniques and circuits are provided to prevent certain operations from being executed during power up or power down conditions.
Claims23
Control means for operating a printer having a printer carriage, paper feed means, carriage drive means and printing means, said control means comprising:
- microprocessor means responsive to data and control codes for controlling printer operations;
- latch means for receiving incoming code words selectively representing data and commands loaded into said latch means by a strobe pulse following each code word;
- means responsive to said strobe pulse for loading each of said code words into said microprocessor means;
- said microprocessor means including memory means for storing character codes;
- examining means for determining the type of code word present, said examining means further including means for generating a buffer full signal when loading the code words into memory means is completed;
- sensor means sensing the location of the printer carriage to generate a start signal when the carriage is in the start position;
- print initiating means in said microprocessor for initiating printing responsive to said buffer full signal and said start signal;
- said printing initiating means including means for setting a predetermined time delay interval and means to reexamine said sensor means in the event that the buffer full signal condition and the start signal are not present at the first examination;
- and means responsive to the presence of said predetermined time interval for reactivating said examining means.
Control means for operating a printer having a printer carriage, carriage driving means, paper feed means and printing means, said control means comprising:
- microprocessor means responsive to incoming data and control code information from a remote source for controlling the operation of the printer;
- drive circuit means for energizing said printing means, said carriage drive means and said paper feed means;
- said microprocessor means including output port means coupled to said drive circuit means for selectively energizing said drive circuit means responsive to controlling signals developed at selected intervals by said microprocessor means;
- said microprocessor means comprising initialization means for setting the conditions at said port means to signal levels preventing erroneous operation of the printer until the proper data and control words have been received from the remote source;
- power supply means to supply power to said microprocessor means;
- and
- clamping means coupled to said drive circuit means and responsive to fluctuations in the output of said power supply means applied to a clamping input of said clamping means for disabling said drive circuit means to prevent erroneous operation of the printer.
A method for operating a microprocessor based control system for a printer having a carriage assembly carriage drive means, paper feed means and printing means coupled to the output ports of the microprocessor through drive circuits, said microprocessor being arranged to receive data and control codes from a remote source for controlling the operation of the printer mechanisms in a predetermined order, said microprocessor comprising assemblies including a data bus;
- input/output ports;
- a program counter;
- a plurality of registers;
- a memory;
- and circuitry including logic circuitry for moving signals between and among the subassemblies;
- said method comprising the steps of:
- preventing any stored data in the microprocessor from erroneously causing printer operations as power is first turned on;
- setting the signal levels at said output ports to disabling signal levels to prevent operation of the printer mechanisms before receiving data from the remote source;
- generating a demand signal for transmission to the remote source advising that the printer is ready to receive data;
- and
- accepting incoming codes from the remote source.
A method for operating a microprocessor based control system for a printer having a carriage assembly, carriage drive means, paper feed means and printing means coupled to the output ports of the microprocessor through drive circuits, said microprocessor being arranged to receive data and control codes from a remote source for controlling the operation of the printer mechanisms in a predetermined order, said microprocessor comprising assemblies including a data bus;
- input/output ports;
- a program counter;
- a plurality of registers;
- a memory;
- and circuitry including logic circuitry for moving signals between and among the subassemblies;
- said method comprising the steps of:
- entering into an acceptance sequence for accepting and storing incoming codes from the remote source;
- entering into an execute sequence activating said drive means, feed means and printing means in a predetermined sequence;
- initiating a time delay interval simultaneously with the initiation of operation of said drive means, feed means and printing means;
- reentering said acceptance sequence during said intervals;
- and
- reentering said execute sequence and the end of said intervals.
Dependencies are inferred from the claim text.