	US 7,603,064 B2
	Unit for tone-processing image data using screen pattern with different screen angles for toners of same hue and different density
Tomohito Ishida, Suntoh-gun (Japan)
Assigned to Canon Kabushiki Kaisha, Tokyo (Japan)
Appl. No. 11/572,978 PCT Filed Sep. 05, 2005, PCT No. PCT/JP2005/016675 § 371(c)(1), (2), (4) Date Jan. 30, 2007, PCT Pub. No. WO2006/028230, PCT Pub. Date Mar. 16, 2006.
Claims priority of application No. 2004-259755 (JP), filed on Sep. 07, 2004.
Prior Publication US 2007/0264050 A1, Nov. 15, 2007
Int. Cl. G03G 15/00 (2006.01)

U.S. Cl. 399—223

5 Claims

1. An electrophotographic color image recording apparatus including:

an image bearing member having photoconductivity;

a charging unit adapted to charge said image bearing member;

an exposure unit adapted to expose the surface of the image bearing member after charging to form an electrostatic latent image;

a developing unit adapted to cause one of plural kinds of toners to adhere to said electrostatic latent image to form a toner image;

a transferring unit adapted to superimpose and transfer plural kinds of toner images obtained by said developing unit; and

a processing unit adapted to execute tone-process to image data to be sent to said exposure unit;

wherein said plural kinds of toners include at least toner of dark color and toner of light color, each said toner having substantially the same hue and different densities from each other, and

wherein said processing unit executes the tone-process by the use of a screen pattern having different screen angles for the respective toner of dark color and the toner of light color;

wherein the tone-process is executed to dispose a screen angle so as to adjoin the screen angles of one or more toner sets of the light color and the dark color and to widen a difference between the screen angles of other toner sets of colors different from the one or more toner sets of the light color and the dark color having substantially the same hue and different densities from each other to be greater than the difference between the screen angles of the one or more toner sets of the light color and the dark color.