Abstract: A method of making a reproduction copy of an image or a document by electrophotography wherein high print density portions of an original image are developed and transferred onto a recording medium before low print density portions of the original image are developed and transferred onto the recording medium. The original image is multiply scanned under successive, controlled conditions to produce a series of latent images, each of which represents a print density component of the original image. Each latent image is developed and transferred onto the recording medium to produce a composite print density and gradation which closely approaches the print density and gradation of the original document or a predetermined density and gradation.

Abstract: A heat fixing device for use in an electrophotographic copying machine in which an electroconductive layer is provided in the surface of one of the fixing and pressure rolls for preventing charge built up upon the surface of the roll. The layer is preferably provided as an aluminum plated layer covered by a non-adhesive releasing layer made of a material such as tetrafluoroethylene or HTV or RTV silicone rubber. Provision of the electroconductive layer prevents an electric field from forming extending through a sheet carrying an image to be fixed thereby substantially entirely, eliminating any offset produced on the roll.

Abstract: A contact heat fixing apparatus comprising heat roll 1 having metal core 3 coated with heat resistant toner releasing material 4 on the surface thereof and provided with a heating element to the inside thereof. Temperature control circuit A comprising detection circuit 15 for the detection of the surface temperature of heat roll 1, comparison circuit 16 for comparing the level of a signal issued from said detection circuit 15 with that of a reference signal, pulse generation circuit 17 for converting the signal produced from said comparison circuit 16 into a pulse and an alternating current power source 12 whose electric power to be supplied to said heating element 11 is controlled by the signal from said pulse generation circuit, and switching circuit B for applying, to said temperature control circuit A, control signals which control the surface temperature of said heat roll 1 to set temperature T.sub.1 during a copy stand-by period, to set temperature T.sub.2 lower than said set temperature T.sub.

Abstract: A heated roll fixing device for electrophotographic copying machines, wherein said device is provided with a first roll 4 which is coated on the surface with a heat-resistant releasing agent 2 , said first roll being adapted to contact toner images 6 on a supporting body 7 . A second roll 5 cooperating with said first roll 4 for pressure-heat-fixing the toner images to said supporting body 7 . The fixing device is characterized in that either said first roll 4 or second roll 5 but at least said first roll 4 is provided with an inner heating means 3, and an outer heating means 13 with small heat capacity is provided in a manner to surround said first roll 4 as illustrated in FIG. 4 of the drawings.