Abstract: An improved electrophotographic (EP) printer is provided having a detachable process cartridge that contains a non-volatile memory device, which is an EPROM that cannot be erased after a bit is burned. A "toner wheel" mounted to the exterior of the toner reservoir of the process cartridge provides, in conjunction with an optoelectronic sensor, an electrical signal that the printer receives and uses to determine toner usage. A toner "gas-gauge" is created which uses "bucket levels" as discrete steps to indicate how much of the measured physical toner material actually remains within the toner reservoir. After a given amount of toner material has been dispensed through the developer unit, one of the bits of the EPROM memory device is irreversibly burned, thereby providing a permanent record on the process cartridge of a certain amount of toner usage.

Abstract: Toner is conserved in printer (1) under operator control by changing the final modulation for each bit in a bit map depending on whether the bit is an edge bit or an internal bit in the character being printed. Since only the final modulation is affected, processing speed and efficiency are not degraded. The operator can select various degrees of internal gray and internal white. Some levels of gray may be satisfactory for some final correspondence.

Abstract: A method of achieving line-to-line synchronization having a high degree of synchronization accuracy. Synchronization is performed by a specific high-speed block of logic which signals the beginning of scans to a PELCLK-based logic at pel boundaries, and provides sub-pel shifting as it passes data between the pel generation logic and a laser control signal. The synchronization error is made as small as propagation delays through a single multiplexer element. Such delays can be controlled to values less than 1/2 ns. The need to stop and restart the clocks is eliminated. All complex pel generation logic is clocked with the relatively low frequency PELCLK without regard to the synchronization task.

Abstract: A facsimile printer (1) in which sets of one or two pels contiguous to longer lines of such pels are reduced or eliminated. When reduced the smaller pels are positioned continuous to the longer line and are extended one pel on each side where the longer line exists. This reduces scanner errors and significantly improves images. Gray effects from dithering are not significantly effected when the pels are reduced and spread. When the image is graphic or otherwise more random than text scanned in the line and column direction, the correction may be deactivated.

Abstract: A method of printing an image on a substrate, where a solid border is printed on the substrate, the solid border corresponding to the perimeter of the image. A dead zone, in which no media is applied, is defined adjacent to and interior of the solid border, and a gray pattern is printed adjacent to and interior of the dead zone. A printer according to the present invention is for printing an image on a substrate, and has a data processing means and printer elements. The data processing means has a solid border controller for adjusting the width of a solid border corresponding to the perimeter of the image, and for producing a solid border parameter. Also included in the data processing means is a dead zone controller for adjusting the width of a dead zone adjacent to and interior of the solid border, and for producing a dead zone parameter.

Abstract: A method of reducing EMI when printing an image with a printer having a laser includes determining edge pels located near an edge of the image, determining interior pels located within the image and not edge pels, forming edge pels by operating the laser at a first duty cycle and forming at least a portion of a plurality of interior pels by operating the laser at a second duty cycle longer than the first duty cycle. Another aspect is a method of reducing EMI in a printer when forming a latent image on a photoconductive member by gating a light source ON and OFF, including the steps of identifying a first region near an edge of an image to be formed, the first region being formed by gating the light source at a first frequency; and identifying an interior region of the image to be formed, the interior region being formed by gating the light source at a second frequency lower than the first frequency.

Abstract: An improved printer is provided that predicts how many pages can be printed before the toner or ink cartridge becomes empty, and also predicts how much time remains before this toner or ink cartridge becomes empty. This prediction is based upon the previous printing history of the printer while using this particular toner cartridge. After measuring the quantity of toner left in the toner cartridge, the printer of the present invention will display the approximate quantity of toner remaining in the cartridge on a screen of a host computer that is connected to the printer, either directly or through a network. The monitor screen of the host computer can also display the predicted number of pages remaining, based on the printer's previous usage history as described above.

Abstract: Toner is conserved in printer (1) under operator control by changing the final modulation for each bit in a bit map depending on whether the bit is an edge bit or an internal bit in the character being printed. Since only the final modulation is affected, processing speed and efficiency are not degraded. The operator can select various degrees of internal gray and internal white. Some levels of gray may be satisfactory for some final correspondence.