Abstract: In a digital imaging system including an array of imaging devices that apply an image to a recording medium such as a lithographic printing plate, elimination or reduction of longitudinal imaging artifacts is accomplished by blending the zones imaged by each the devices. In the course of a complete scan of the recording medium, the imaging devices each traverse a series of longitudinal columns of dot locations, and the devices are fired only at appropriate dot locations as determined by the digital image data. By operating adjacent imaging devices such that the zones they would ordinarily cover are blended in a random pattern, artifacts at the boundary between zones (such as seams) are hidden. While sufficient visual disruption to eliminate artifacts is ensured, noticeable visual artifacts are not created as a consequence of the disruption.

Abstract: Compensation for the effects of duty cycle on the output level of an imaging device, and for the effects of periodically varying distance between the output of the imaging device and its target, is accomplished electronically. An exemplary apparatus includes a source of radiation (generally a laser) having an output level that varies both with an input power level and, undesirably, with the duty cycle. The radiation source is operated to produce, on the recording surface, an imagewise pattern of spots, and an adjustment facility compensates for output-level variations resulting from duty cycle--that is, from the recent pattern of laser activity.

Abstract: In a digital imaging system including an array of imaging devices that apply an image to a recording medium such as a lithographic printing plate, elimination or reduction of longitudinal imaging artifacts is accomplished by blending the zones imaged by each the devices. In the course of a complete scan of the recording medium, the imaging devices each traverse a series of longitudinal columns of dot locations, and the devices are fired only at appropriate dot locations as determined by the digital image data. By operating adjacent imaging devices such that the zones they would ordinarily cover are blended, artifacts at the boundary between zones (such as seams) are hidden. While sufficient visual disruption to eliminate artifacts is ensured, noticeable visual artifacts are not created as a consequence of the disruption.

Abstract: An ink-jet apparatus in which a recorded image is read to provide a image reference signal for comparison with an image recording signal, the resulting comparsion being used as a basis for diagnosing an ink injection state of a recording head nozzles in order to determine and implement an ink injection recovery process.

Abstract: A system for efficiently generating on a raster line plotter an image that is made up of a plurality of characters, or other objects, based on an opaque ink model. Information relating to the characters is run length encoded, so as to form tone run records corresponding to the raster lines. The tone run records contain information relating to tone value, starting location, length and screen selection. The information is then processed so as to delete, or overwrite, tone value and screen selection information of the portions of characters that underlie other characters. After the appropriate information has been deleted, the remaining screen selection and tone value information is used to create a halftone image.