Abstract: Multiple host computers on a network are connected through an interface, or network adapter, to a printer having a printer controller capable of bi-directional communication with the computers on the network. The interface communicates with the network computers in a manner to present a different virtual printer to each host computer. The interface maintains a data set for each host computer which includes designations of the types of printer status information of interest to that host. The interface is capable of communicating with the printer controller to obtain a range of printer status information, and the interface communicates with each host computer to present printer status information of interest to that computer based upon that computer's data set. In the disclosed form of the invention, the interface notifies each interested host computer concerning types of printer status information to which changes have occurred; and the host computers communicate requests for more detailed information.

Abstract: An ink jet printer cartridge assembly including a cartridge body with at least one ink chamber from which ink flows to a print head. A standpipe in the ink chamber includes an opening therethrough for the flow of ink to the print head, and a filter cap is secured on the top of the standpipe to limit the introduction of air bubbles and particulate matter in the flow of ink toward the print head. The filter cap includes a mesh material formed into a dome-shaped configuration and an elastomeric material molded about the periphery of the mesh portion, with the elastomeric material being received around the top portion of the standpipe.

Abstract: A print quality enhancement arrangement for a dot matrix printer such as a thermal ink jet printer. The arrangement includes a buffer for receiving 300 dots per inch (dpi) resolution data in the horizontal (print head movement) direction and creates 600 dpi resolution data using image enhancement techniques. The arrangement further includes correction of the higher resolution data to remove pels which are unprintable due to the frequency response of the print elements in the print head. The correction is performed using knowledge of the history of printed pels and the original 300 dpi data. The creation of the higher resolution data and its correction occur "on-the-fly" as data is being fed to the print head, rather than through the creation of a 300 by 600 dpi bitmap.

Abstract: A method and apparatus for inserting a compressed foam block into a generally rectangular ink jet print head ink chamber. The foam is compressed in an insertion tool which includes a compression area and compression fingers extending therefrom. A block of foam is placed in the principal area of the insertion tool and compressed in two dimensions, following which the ink jet print head is positioned around the compression fingers. The foam is pushed from the principal part of the insertion tool into the area surrounded by the compression fingers inside the print head ink chamber, and the force applied to the foam is continued. At a certain force level, the cartridge is allowed to move, under the force applied to the foam, off of the insertion fingers, leaving the foam inside the cartridge.

Abstract: A low profile tactile keyswitch including a horizontally positioned elastic column spring which buckles under an axial load to provide a tactile feel for the keyswitch. The ends of the spring are maintained between two spring holders which are urged together as the keybutton is depressed. Stabilizing arms pivotally attached to the keybutton are used to stabilize the keybutton and also to carry extensions which engage the spring holders to move them together as the keybutton is depressed. The keyswitch is operable to be placed in an inactive configuration in which the keybutton is lowered without placing the spring under added compression.

Abstract: An electrophotographic printer (11) including a fuser (16, 17) for fusing a toned image onto an envelope (13) passing through a fuser nip (14). Wrinkling and treeing of the envelope (13) is substantially eliminated by removing the pressure on the envelope (13) in the fuser nip (14) for one or more brief intervals during the fusing process. To do this, a solenoid (21) is intermittently driven to remove the force of a spring (18) urging the fuser rolls (16, 17) together.

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: An electrophotographic printer (11) having a base (13) and a top (12), the top (12) being pivotable about an axis (23) between a closed position and an open position. The printer (11) receives a supply cartridge (14) on a shelf (22) which is pivotable about the same axis (23) as the top (12) of the printer (11). A counterbalance spring (34) helps to support the shelf (22) and the cartridge (14) below the top (12) of the printer (11) and above the printer base (13) when the top (12) of the printer (11) is in its open position. When the top (12) of the printer (11) is closed, the cartridge (14) is urged into a position adjacent the printer base (13) and locked into an operative position.