초록 ▼

An improved non-stop, constant velocity laser printer is provided which operates in parallel to both begin printing a particular page of print media while virtually simultaneously receiving further data for that same page from a host computer. Since the communications link between the host computer

An improved non-stop, constant velocity laser printer is provided which operates in parallel to both begin printing a particular page of print media while virtually simultaneously receiving further data for that same page from a host computer. Since the communications link between the host computer and the printer is slower than the rate of consumption by the printhead provided with this printer, a certain amount of data for each page is first buffered in the printer before the print media begins to move via the printer's print engine. Since it is important for the printer to receive all of the required data for the entire page before the printhead requires that data for consumption, the printer must decide how much data of that particular page should be buffered within the printer before commanding the print engine to start moving the print media. The printer is capable of making this "data size" to be buffered decision without any assistance from the host computer that is sending the print job to the printer-all the host need send is the standard page header information that all host computers send when transmitting a rasterized print job to a printer. The printer bases its "data size" decision by estimating the amount of data by using the print resolution, an estimate of the compression ratio, and other information from the page header that provides a rough estimate as to how much of the area of the page of the print media is to be covered, and by estimating the communication link speed, and the amount of time that is available to perform the data transfer. Since print data is received in packets, as each packet is received, stored, and acknowledged by the printer before another packet is sent by the host, the amount of time for all of this to occur for each packet is analyzed to calculate an estimate of the approximate data transfer rate of the communications link, which is refined after receiving each new packet, but is recalculated for each new page.

대표청구항 ▼

[ I claim:] [1.] In a serialized constant-velocity page printing system having a memory circuit containing a receive buffer, a communications port that is effectively connected to at least one external device, a print engine, and a processing circuit, a method of efficiently printing a page of print

[ I claim:] [1.] In a serialized constant-velocity page printing system having a memory circuit containing a receive buffer, a communications port that is effectively connected to at least one external device, a print engine, and a processing circuit, a method of efficiently printing a page of print data, said method comprising:(a) for each page to be printed, calculating a threshold value related to a quantity of print data at said printing system, without receiving a data value from any one of said at least one external device that would directly set a pre-determined value corresponding to said threshold value of print data, wherein said calculation includes evaluating an actual data transfer rate from said external device through said communications port, as measured by said constant-velocit page printing system;(b) receiving print data from said at least one external device via said communications port for a portion of a particular page of a print job until said threshold value of print data has been received into said receive buffer; and(c) after detecting that said threshold value of print data has been received, commanding said print engine to begin printing said particular page, at a print engine transport speed that is determined only by a print resolution for said particular page, before all of the print data for said particular page has been received by said printing system, wherein said threshold value of print data represents a value less than the amount of print data corresponding to the entire particular page.