Abstract: An improved printing system is provided having at least one host computer and a printer in which the printer acquires print job accounting information and communicates it to the host computer via NPAP messages. A host computer downloads print job data to the printer through a communications port on the printer (i.e., either a parallel port, serial port, or network port), and as the printer prints the print job that it received from the host computer, the printer temporarily stores job accounting information. At the end of the print job, the printer communicates that job accounting information back to armed host computers via a bi-directional communications port, including typical information such as: the job identifier number, job processing time, number of sheets of paper from each paper source, number of impressions from each paper source (either one-sided or two-sided impressions), the port identifier, the network user name, the name of the print job (as specified), and the printer's serial number.

Abstract: An improved DC servo motor driver circuit is provided that is based upon a readily available conventional stepper motor driver integrated circuit (IC). The IC's current "Sense" line that is usually connected to a low value resistor is instead tied to DC common or to ground. The IC's "Comparator" input, which is usually connected to the current Sense line, is connected to a pulsing input signal that provides the comparators with an appropriate voltage to make the comparators believe that more current is required at the very times the remaining portions of the circuit are attempting to provide current to the DC servo motor. An RC circuit is provided at the IC's "Pulse Time" input so that the monostable timer is properly triggered. An ASIC provides the proper logic signals to not only control the direction of the DC servo motor, but also to provide pulses of an appropriate frequency and duty cycle to emulate a pulse-width modulator.

Abstract: An improved printing system is provided that compresses bitmap print data by determining, per each vertical slice of a horizontal swath of the printed page, which one of two different data compression techniques to more efficiently compresses each individual slice, then temporarily stores this compressed data in a memory circuit until needed by the printhead for actual printing of the final output in the form of print media. When using slices containing seven (7) different words per slice, the present invention utilizes a single "control bit" of a "control word" to represent each of the data words of the slice. Depending upon which type of compression technique is used, the control bit for each data word will be set to either Logic 1 or Logic 0, depending upon the value of the data word as compared to a pre-determined data word value that is chosen by the system, and which may be used in both types of data compression techniques.

Abstract: A hydro-buoyant electrical power generating plant is provided which generates electricity from a source of hydraulic pressure. The energy that pressurizes the hydraulic fluid is derived from movements of a crane-like class II lever that has its fulcrum fixed to a stationary land mass so that the fulcrum's position is fixed relative to the lever's opposite "movable" end where the applied load is established. The movable end of the lever is attached to an "applied force vessel" that alternatively can be filled with water (or other liquid) so as to sink due to gravity, and then can be evacuated of water so as to rise due to buoyancy. When the applied force vessel is at its position of greatest elevation, the interior chamber of the vessel initially would be filled with air, typically at atmospheric pressure.

Abstract: An improved communications buffer system is provided which dynamically allocates the size and number of buffers to optimally receive packets of communications data over a communications link, while efficiently using the amount of available memory so as to provide optimal throughput capability with respect to the allocated amount of memory. This buffer system is readily adaptable for infrared communications ports used on printers. Once a communications session has begun, the printer will obtain sufficient information to most effectively allocate the size and number of buffers. At the beginning of this procedure, the printer must first determine how much "free" memory is available in its "pool area" and then determine how best to divide up that pool area into both transmit and receive buffers. The size and number of transmit buffers is first determined, and this determination is made after considering how much pool area is available in the printer's memory system at that moment.

Abstract: An improved area monitor for detecting gas concentration is provided that requires a very infrequent calibration, and works reliably in detecting a particular target gas using only two semiconductor sensors. One of these sensors will exhibit a drift that is constantly monitored and automatically compensated for, while the other sensor exhibits a stable, repeatable response over very long periods of time. Once the "stable" has been initially calibrated, the concentration of the target gas can be discerned directly from the resistance of this sensor, although more that one particular chemical gas may cause the stable sensor to change resistance. The second sensor is then used to discern whether or not the change in resistance of the stable sensor was due to the actual target chemical, or due to some other similar chemical. The second sensor is selected to be of a type that responds in one direction (i.e.

Abstract: Apparatus, system and method is provided in which a primary printer prepares print data for use by its resident print engine, or by an alternate printer. The primary printer includes subsystems for receiving original print data from a device, such as a computer or scanner, and for converting the original print data into a data format compatible with the alternate printer.

Abstract: A magnetically-powered linear displacement device is disclosed which can be used as the highly efficient pollution-free prime mover. The linear displacement device utilizes a permanent magnet whose flux density can be readily shifted from one of two parallel magnetic paths within the displacement device. A pair of pole pieces made of magnetically soft material abuts portions of the permanent magnet and conducts the magnetic flux in two different magnetic circuit pathways such that the permanent magnet's flux can flow in either direction, and if the magnetic flux is travelling along a first of these parallel paths through a movable armature, that armature will be attracted toward the ends of the pole pieces. If the magnetic flux is then shifted to the second path of these two parallel paths, then that movable armature will not be attracted to the pole pieces, and a compression spring can be used to push that movable armature away from the pole pieces.

Abstract: An improved printer is provided that improves the response time before jobs are printer by providing a "fast data path" for certain print jobs while also storing on a hard disk all incoming print job data. This "fast data path" is especially useful in situations where the incoming print job lacks an "end of file" code, which could otherwise hold up the processing of either this print job or later print jobs. Once the printer becomes relatively busy, and begins to accumulate a "queue" of print jobs waiting to be processed and printed, the printer will automatically store all of the print job data on the non-volatile memory (e.g., a hard disk) before that same data is sent to the processing circuitry.

Abstract: A magnetically powered linear displacement device is disclosed which can be used as the highly efficient prime mover. The linear displacement device utilizes a permanent magnet whose flux density can be readily shifted from one of two parallel magnetic paths within the displacement device. A pair of pole pieces made of magnetically soft material abuts portions of the permanent magnet and conducts the magnetic flux in two different magnetic circuit pathways such that the permanent magnet's flux can flow in either direction, and if the magnetic flux is travelling along a first of these parallel paths through a movable armature, that armature will be attracted toward the ends of the pole pieces. If the magnetic flux is then shifted to the second path of these two parallel paths, then that movable armature will not be attracted to the pole pieces, and a compression spring can be used to push that movable armature away from the pole pieces.

Abstract: An improved printing system is provided having at least one host computer and a printer in which the printer acquires print job accounting information and communicates it to the host computer via NPAP messages. A host computer downloads print job data to the printer through a communications port on the printer (i.e., either a parallel port, serial port, or network port), and as the printer prints the print job that it received from the host computer, the printer temporarily stores job accounting information. At the end of the print job, the printer communicates that job accounting information back to armed host computers via a bi-directional communications port, including typical information such as: the job identifier number, job processing time, number of sheets of paper from each paper source, number of impressions from each paper source (either one-sided or two-sided impressions), the port identifier, the network user name, the name of the print job (as specified), and the printer's serial number.

Abstract: A dispersed-dot stochastic dither array is provided for rendering halftone images having excellent visual quality and are created by a minimum density variance method. The minimum density variance method considers the statistical distribution of the pixels in the image, and is unrelated to previous techniques based on either spatial frequencies or spatial distances, such as the blue noise mask and the void and cluster algorithm. By minimizing the variance in the number of dots within each local region of the image, a smooth and dispersed distribution of dots may be obtained. The method of the present invention also offers the flexibility to accommodate particular design considerations, through the selection of the size and shape of the image regions, the weighting of the cost function, and the option of guiding the selection of dots with "target" dot profile images.

Abstract: An External Network Adapter (ENA) is provided that acts as an interface between a network and a parallel or serial port of at least one printer, in which host computers on the network may send print jobs to the External Network Adapter, and these print jobs will be communicated to the printers in a manner that the print jobs will be printed correctly. The External Network Adapter can additionally receive NPAP queries and NPAP commands from a host computer over the network, and transfer those NPAP queries or commands to each of the printers at virtually any time, including during a print job. If the ENA receives any NPAP query or NPAP command from a host computer via the network, such NPAP queries or commands are sent to the printer between print job packets.

Abstract: A method for smoothing expanded bitmap data is provided for use in laser printers or computers that use two-state, two-dimensional image data created by word processors, computer-aided drafting systems, and the like. The method would typically be utilized within a laser printer at its common graphics engine, just after the input source data has been rasterized. The source bitmap data having low-resolution pels is first divided into higher resolution pels, and the appearance of its diagonal lines would otherwise have a jagged appearance if such data is not smoothed. Once the expansion factor is determined, the present method takes pel data in word-sized portions and performs (in an Outer Loop) various logical operations upon these words of data to smooth adjacent rows of the higher-resolution pels. Each pair of words of pels is evaluated through a series of logical operations in an Inner Loop, before indexing to the next group of pels in the same row and starting a new Outer Loop.