Photo printer having a host computer assist function and method of controlling the same

A method of controlling the operation of a photo printer having a communication circuit for implementing a bidirectional data communication with a host computer, a volatile memory, a data converting circuit which converts coded print data sent from said host computer through said communication circuit into print dot data and stores the print dot data in said volatile memory, a printer engine which prints the print dot data stored in said volatile memory on print paper, and an interface circuit for receiving image data from an image scanner, comprising:

• a first step of, in response to a first command issued by said host computer indicating a print request, converting print data sent from said host computer into dot data, storing the dot data in said volatile memory, and printing the dot data with said print engine;
• a second step of, in response to a second command issued by said host computer indicated a scanner start request, storing temporarily image data from said interface circuit in said volatile memory;
• and
• a third step of, in response to a third command issued by said host computer indicating a transfer request, sending the image data which has been received by said interface circuit and stored in said volatile memory to said host computer.

A photo printer system comprising:

• communication means for implementing bidirectional data communication with a host computer;
• a data read/write nonvolatile memory and a data read/write volatile memory;
• data developing means for developing coded print data sent from said host computer through said communication means into print dot data and for storing the print dot data in part of said volatile memory;
• a photo printer engine for printing said developed and stored print dot data on print paper;
• and
• request management means, operated by a program, for managing a print process request and a non-print process request issued by said host computer, said request management means comprising processor means for operating said nonvolatile memory as an auxiliary storage for said host computer in response to a non-print process request issued by said host computer and for operating said volatile memory as a cache memory for said nonvolatile memory in response to a data read/write command issued by said host computer.

A photo printer system comprising:

• communication means for implementing bidirectional data communication with a host computer;
• a volatile memory;
• data developing means for developing coded print data sent from said host computer through said communication means into print dot data and storing the print dot data in said volatile memory;
• a photo printer engine for printing said developed and stored print dot data on a sheet;
• interface means for receiving image data from an image scanner and for storing the image data in said volatile memory;
• and
• processing means responsive to a print process request for initiating a print mode in which coded print data is developed by said data developing means into print dot data which is then stored in said volatile memory for printing by said photo printer engine, and responsive to an image scanner start request and a data transfer request from said host computer for initiating a non-print mode in which image data picked up by said image scanner is temporarily stored in said volatile memory in response to the image scanner start request, and afterward the stored image data is sent from said volatile memory to said host computer in response to the data transfer request.