Abstract: Printer (1) monitors current control language being interpreted for end of page and end of job codes, depending upon the language. Upon observing such commands, up to 500 bytes in buffer memory (19) are observed for command codes characteristic of specific languages. ASCII language is recognized by any one of several command codes, many of which have ESC. PostScript language is recognized by any one of several commands including the ASCII sequence of the percent sign. PCL4 or PCL5 and pen movement graphics languages are also recognized. Operator intervention and special coding defining the language are completely avoided.

Abstract: A memory management system for a page printer controller (11) which includes random access memory (17) allocated among bit map memory (30), page buffer memory (29), and user memory (28). The memory management system allocates the random access memory to provide either a large bit map memory or, responsive to needs of the controller (11) for increased memory for other uses, for allocating the random access memory (17) to provide a small bit map memory and place more memory in the page buffer memory (29) and user memory (28).

Abstract: A page printer (101) which rasterizes a page utilizing partial page bit map swaths. Received data to be printed is stored in packets (12-17) in a page buffer in random access memory (105). Data within each packet is arranged in printing order down the page to be printed, but the packets themselves are arranged in the order received, and are not indexed or linked. As each swath (11) is rasterized, each packet is examined, and packets containing data falling at least in part within the active swath are processed. The printer is controlled by a programmed microprocessor, and logic hardware assistance is provided for translating data addresses from logical addresses (54) to physical addresses (52). Logic hardware assistance is also provided for making the determination of whether or not a given data address lies within the active swath.

Abstract: A printer having a print engine (13) and a bit map memory (12) including a number of page image areas (31) into which information to be printed is rasterized and from which information for the print engine is serialized. A digital processor (11) controlling the print engine is operable to reduce a page image area (31) to a modified page image area (37) based upon the highest and lowest addresses at which information has been written into the page image area. The digital processor (11) is also operable to begin rasterization of a new page image area when a sufficient amount of an existing page image area (41) has been serialized to make available the requisite bit map memory for the new page.

Abstract: A matrix printer (1) or other imaging device in a memory (7) stores fonts of character data (11, 11') in defining bit maps for each character of the fonts. The memory also stores shift values for each font which vary with the nature of the font for double strike, emphasize, and combined double strike and emphasize, from which character bit maps are modified before printing by being shifted and overlayed. Improved images for double strike and emphasize are achieved, and the combined double strike and emphasize need not be the overlay of double strike and emphasize.