초록 ▼

Print enhancement circuits for an electrophotographic printing machine are placed between the character generator and the printhead to modify drive signals for the printhead. Modifications include smoothing the digitized edges of slanted lines; broadening single pel width lines in the direction perp

Print enhancement circuits for an electrophotographic printing machine are placed between the character generator and the printhead to modify drive signals for the printhead. Modifications include smoothing the digitized edges of slanted lines; broadening single pel width lines in the direction perpendicular to the scan direction as well as in the direction parallel to scan. Inhibiting circuits are provided to prevent passage of enhancement signals under certain conditions. Generally, leading and trailing edge gray signals are provided next to all black data in a direction parallel to scan while expanded black signals are provided for the single pel data in a direction perpendicular to scan by adding to the black signal on both its leading and trailing edges. When a single picture element (pel) area contains two added black signals, both are passed; when a single pel area contains one added black signal and one gray signal, both are passed; when a single pel area contains two gray signals, only the leading gray signal is passed; and when a single pel area contains two added black signals and a gray signal, only the gray signal is passed.

대표청구항 ▼

An electrophotographic printing machine comprising: drive means; movable carrier means driven by said drive means; photoreceptive material mounted on said movable carrier means for cyclic movement through electrophotographic process stations; charge corona means located at a first station for placin

An electrophotographic printing machine comprising: drive means; movable carrier means driven by said drive means; photoreceptive material mounted on said movable carrier means for cyclic movement through electrophotographic process stations; charge corona means located at a first station for placing a relatively uniform electrostatic charge on the surface of said photoreceptive material; exposure means located at a second station for selectively discharging the charged photoreceptive material to cause the formation of a latent image on said material; toner for developing said image; developer means located at a third station for applying said toner to said image to produce a developed image; image receiving material; transfer means located at a fourth station for transferring said developed image from said photoreceptive material to said image receiving material; paper storage means for holding a supply of image receiving material; a finishing station; paper forwarding means for serially moving image receiving material from said storage means through the transfer station to said finishing station; control means for operating said exposure means, said control means comprising: a character generator for producing data signals to drive said exposure means to produce the desired image on said photoreceptive material; and enhancement means for altering certain of said data signals before presentation of said signals to said exposure means to produce smoothing of diagonal lines on said photoreceptor and broadening of fine lines in both horizontal and vertical directions on said photoreceptor whereby a print produced from an image generated in accordance with the altered signals is of an enhanced visual quality displaying easily discernible fine lines and smooth diagonal lines.