US 2003/0142996 A1 · Image forming apparatus

Abstract

In the image forming apparatus of this invention, developing rollers of plural color developing units having respective color developers are arranged at an equal space of a first distance along the circumference in contact with an image carrier separately from a black developing unit and on the other hand, the developing rollers from the last part in the revolving direction of a revolving body to the foremost part in the revolving direction are arranged at a space of a second distance that is longer than the first distance, a revolving-type developing device to supply a color developer to the image carrier by bringing anyone of plural color developing units to oppose to the image carrier, and for the developing roller at the last part in the revolving direction to the developing roller at the foremost part separated by the second distance, a black developer is supplied to the image carrier by the black developing unit.

Claims19

Dependent claims

An image forming apparatus comprising:

an image carrier;
a latent image forming unit to form latent images on the image carrier;
a black image developing device arranged near the image carrier to supply a black developer to the image carrier;
and
a revolver type developing device arranged at a position near the image carrier and differing from the black developing unit, comprising developing rollers of plural color developing units which have different color developers arranged at equal space of a first distance along the circumference of a revolving body in contact with the image carrier and on the other hand, the developing unit at the last part in the revolving direction of the revolving body to the developing unit at the foremost part in the revolving direction are separated at a second distance longer than the first distance, and anyone of the plural color developing units is arranged opposing to the image carrier and supply a respective color developer;
and
it is characterized in that for the area from the developing unit at the last part of the revolving-type developing device to the foremost developing unit separated by the second distance opposing to the image carrier, a black developer is supplied to the image carrier by the black developing device.

4 more elements

An image forming apparatus comprising:

an image carrier:
a latent image forming unit to form a latent image on the image carrier;
a black developing unit arranged near the image carrier to supply black developer to the image carrier;
and
a revolver type developing units arranged at a position near the image carrier and differing from the black developing unit, comprising developing rollers of plural color developing units which have different color developers arranged at equal space of a first distance along the circumference of a revolving body in contact with the image carrier of the revolving holder and on the other hand, the developing roller at the last part in the revolving direction of the revolving holder to the developing roller at the foremost part in the revolving direction are separated at a second distance longer than the first distance, and anyone of the plural color developing rollers is arranged to oppose to the image carrier and supply a respective color developer;
and
it is characterized in that for the area from the developing roller at the last part of the revolving-type developing unit to the developing roller at the foremost part separated by the second distance opposing to the image carrier, a black developer is supplied to the image carrier by the black developing device.

4 more elements

Dependencies are inferred from the claim text.

Image forming apparatus

Life of this patent

Image forming apparatus

Life of this patent

Abstract

Claims19