US 5,204,729 A · Full color copying machine

Abstract

A full color copying machine which includes intermediate transfer medium whereon toner images having respective color components, formed on a photoreceptor are transferred to form one color toner image, and a screen filter disposed so as to be freely inserted or removed in or from a path of exposure light, which filters the exposure light for exposing the photoreceptor into a pattern of lines. A plurality of color toner images obtained by executing a plurality of copying processes based on a plurality of exposures applied to an original document are superposed on the intermediate transfer medium to form a color toner image. The copying machine further includes a screen mode for inserting a screen filter into a path of exposure light and a normal mode for removing the screen filter from the path of exposure light. Thus, exposures intended for low density components and high density components in an original document image are respectively performed by the use of the different modes, or they are respectively performed by changing setting conditions of the screen filter in the screen mode. With these arrangements, efficient application of the exposure device and high quality of the copied images can be achieved.

Claims16

Dependent claims

A color copying machine for reading an image on a document having a high-density portion and a low-density portion and for forming a copied image on copy materia, the machine comprising:

scanning means for scanning an original document a plurality of times and forming corresponding pluralities of electrostatic latent images of both the high-density portion and low-density portion of the document,
a screen filter, freely insertable into and removable from a path of light reflected from an original document, for filtering the reflected light into a pattern of lines,
a photoreceptor upon which a plurality of electrostatic latent images of both the high-density portion and low-density portion are formed,
first toner image forming means for forming a first color toner image from the plurality of the electrostatic images relating to the high-density portion,
second toner image forming means for forming a second color toner image from the plurality of the electrostatic latent images relating to the low-density portion,
complete toner image forming means for forming the copied image form a superposition of the first color toner image and the second toner image,
whereby said screen filter is inserted into the path of the light when the plurality of electrostatic latent images of the low-density portion are formed.

4 more elements

A method for forming color toner images in a color copying machine comprising:

removing a screen filter from a path of exposure light;
scanning an original document a plurality of times and forming on a photoreceptor a corresponding plurality of electrostatic latent images corresponding to a high-density portion of the document;
forming a plurality of toner images corresponding to the electrostatic latent images that correspond to the high-density portion of the document;
forming a first color toner image by superposing the plurality of toner images that correspond to the high-density portion;
inserting the screen filter into the path of the exposure light;
scanning the document a plurality of times and forming on the photoreceptor a corresponding plurality of electrostatic latent images of a low-density portion of the document;
forming a plurality of toner images corresponding to the electrostatic latent images that correspond to the low-density portion;
forming a second color toner image by superposing the plurality of toner images corresponding to the low-density portion;
and
forming a copied image by superposing the second color toner image and the first color toner image.

7 more elements

Dependencies are inferred from the claim text.

Full color copying machine

Life of this patent

Full color copying machine

Life of this patent

Abstract

Claims16