Nonimpact printer

Claim 2

A nonimpact printer comprising: a recording medium movable in a predetermined direction; single charging means for uniformly charging said recording medium; means for forming a first latent image of electric charges on said recording medium; first developing means for developing said first latent image into a first visible image; means for forming a second latent image of electric charges on said recording medium with said first visible image formed thereon; and second developing means for developing said second latent image into a second visible image having a color different from that of said first visible image, the bias voltage for said second developing means being set higher than the bias voltage of said first developing means, said single charging means, said first latent image forming means, said first developing means, said second latent image forming means, and said second developing means being arranged, in that order, in the direction of movement of said recording medium whereby a visible image of a plurality of colors is formed on said recording medium during one cycle of movement of said recording medium.

Claim 3

A nonimpact printer as claimed in claim 1, wherein said second developing means uses one component developer having a high electric resistivity.

Claim 4

A nonimpact printer as claimed in claim 1, wherein said second developer means uses a developer including polarizable magnetic toner having a high electric resistivity.

Claim 5

A nonimpact printer as claimed in claim 1, wherein the tone of the developer used in said second developing means is lower than the tone of the developer used in said first developing means.

Claim 6

A nonimpact printer according to claim 1, wherein the bias voltages of said first and second developing means are of the same polarity.

Claim 7

A nonimpact printer comprising: a drum-like rotary photosensitive medium mounted for rotary movement in a predetermined direction; single charging means for uniformly charging the surface of said photosensitive medium; first exposure means for exposing the uniformly charged surface of said photosensitive medium to an exposure light of a first exposure light source thereby to form a first latent image on the surface of said photosensitive medium in which electron charges are discharged from an area thereof desired to allow a toner to adhere; first developing means for forming a first toner image by allowing a first toner of one color to adhere to an area from which electron charges are discharged with reversal development of said first latent image by said first toner charged at the same polarity as that of the uniform charge; second exposure means for exposing the surface of said photosensitive medium to exposure light of a second exposure light source to form a second latent image in the area where electron charges remain other than the area where the first toner image is formed on the surface of said photosensitive medium; second developing means for forming a second toner image by allowing a second toner of another color to adhere to the area from which electron charges are discharged with reversal development of said second latent image by said second toner charged at the same polarity as that of the uniform charge; and transfer means for simultaneously transferring said first and second toner image formed on the surface of said photosensitive medium to a recording medium; said single charging means, said first exposure means, said first developing means, said second exposure means, said second developing means, and said transfer means being arranged, in that order, in the direction of rotary movement of said drum-like rotary photosensitive medium, whereby a toner image of a plurality of colors is formed on said photosensitive medium during one cycle of rotation of said photosensitive medium.

Claim 8

A nonimpact printer comprising: a drum-like rotary photosensitive medium mounted for rotary movement in a predetermined direction; single charging means for uniformly charging the surface of said photosensitive medium; first exposure means for exposing the uniformly charged surface of said photosensitive medium to an exposure light of a first exposure light source thereby to form a first latent image on the surface of said photosensitive medium in which electron charges are discharged from an area thereof desired to allow a toner to adhere; first developing means for forming a first toner image by allowing a first toner of one color to adhere to an area from which electron charges are discharged with reversal development of said first latent image by said first toner charged at the same polarity as that of the uniform charge; second exposure means for exposing the surface of said photosensitive medium to exposure light of a second exposure light source to form a second latent image in the area where electron charges remain other than the area where the first toner image is formed on the surface of said photosensitive medium; second developing means for forming a second toner image by allowing a second toner of another color to adhere to the area from which electron charges are discharged with reversal development of said second latent image by said second toner charged at the same polarity as that of the uniform charge; and transfer means for simultaneously transferring said first and second toner image formed on the surface of said photosensitive medium to a recording medium; said single charging means, said first exposure means, said first developing means, said second exposure means, said second developing means, and said transfer means being arranged, in that order, in the direction of rotary movement of said drum-like rotary photosensitive medium, whereby a toner image of a plurality of colors is formed on said photosensitive medium during one cycle of rotation of said photosensitive medium.

Claim 9

A nonimpact printer according to claim 6, wherein said first and second exposure light sources each comprise a laser beam generator.

Claim 10

A nonimpact printer according to claim 6, wherein said first and second exposure light sources comprise a first laser beam generator for producing a first laser beam corresponding to said first exposure light source and a second laser light generator for generating a second laser beam corresponding to said second exposure light source, respectively, and said first and second exposure light sources comprise single mirror scanner means for deflection scanning of said first and second laser beams.

Claim 11

A nonimpact printer according to claim 6, wherein said first and second exposure light sources comprise means for splitting a laser beam produced from a single laser beam generator into a first and a second laser beam and single mirror scanner means for deflection scanning of said first and second laser beams.

Claim 12

A nonimpact printer according to claim 8 or 9, comprising a single lens, said first and second laser beams subjected to deflection scanning by said single mirror scanner means being guided into said first and second exposed positions through said single lens.

Claim 13

A nonimpact printer according to claims 6, 7, 8 or 9, wherein said first and second developer means each comprise a bias power source for providing a bias voltage having the same polarity as the uniform charge, the bias voltage applied to said second developer means being higher than that applied to said first developer means.