A print system comprising: a first printer; and a print data output apparatus that is communicably connected to the first printer after having been disconnected from a second printer different from the first printer; wherein the print data output apparatus comprises: an internal print data generation section adapted to generate, by executing any of a plurality of programs (33, 35), internal print data for forming an image on an image recording medium, the internal print data being compatible with the second printer and including data for specifying at least one font that is stored in the second printer; a spooler to which the internal print data generated by the internal print data generation section is supplied; a port driver adapted to supply to the first printer, through a port for a communication connection to the first printer, print data supplied from a monitor section; a printer-retained information storage unit adapted to store a font image data corresponding to a font that is stored in the second printer and second printer-retained information that is based on information stored in the second printer; a monitor section adapted to monitor whether or not the internal print data is supplied from the spooler; a print data conversion section adapted to convert the internal print data into print data compatible with the first printer when the monitor section detects the supply of the internal print data from the spooler, the print data conversion section comprising: an intermediate data generation section adapted to generate raster image data based on the internal print data, the font image data and the second printer-retained information; and a print data generation section adapted to generate print data used for causing the first printer to form the image on the image recording medium based on the raster image data; wherein the monitor section is further adapted to supply the print data generated by the print data generation section to the port driver. a first printer; and a print data output apparatus that is communicably connected to the first printer after having been disconnected from a second printer different from the first printer; an internal print data generation section adapted to generate, by executing any of a plurality of programs (33, 35), internal print data for forming an image on an image recording medium, the internal print data being compatible with the second printer and including data for specifying at least one font that is stored in the second printer; a spooler to which the internal print data generated by the internal print data generation section is supplied; a port driver adapted to supply to the first printer, through a port for a communication connection to the first printer, print data supplied from a monitor section; a printer-retained information storage unit adapted to store a font image data corresponding to a font that is stored in the second printer and second printer-retained information that is based on information stored in the second printer; a monitor section adapted to monitor whether or not the internal print data is supplied from the spooler; a print data conversion section adapted to convert the internal print data into print data compatible with the first printer when the monitor section detects the supply of the internal print data from the spooler, the print data conversion section comprising: an intermediate data generation section adapted to generate raster image data based on the internal print data, the font image data and the second printer-retained information; and a print data generation section adapted to generate print data used for causing the first printer to form the image on the image recording medium based on the raster image data; wherein the monitor section is further adapted to supply the print data generated by the print data generation section to the port driver. an intermediate data generation section adapted to generate raster image data based on the internal print data, the font image data and the second printer-retained information; and a print data generation section adapted to generate print data used for causing the first printer to form the image on the image recording medium based on the raster image data; wherein the monitor section is further adapted to supply the print data generated by the print data generation section to the port driver.