Image forming apparatus and image forming method

Claim 2

An image forming apparatus for recording images, comprising: an image processing unit to create image data for output including toner image data on four colors of yellow, cyan, magenta, and black such that toner images have line-shaped periodic structures; and an image forming unit to form the toner images using coloring materials of the four colors and superposing the toner images on a recording medium, wherein the line-shaped periodic structures of the toner images of the four colors are determined based on a combination of periodic structures having screen ruling and screen angles specified in table 1 below: TABLE 1 No. ruling angles a0x a0y a1x a1y 0 180.3 33.7 3 2 3 −2 1 180.3 146.3 −3 2 3 2 2 200.0 0.0 3 0 0 −3 3 200.0 90.0 0 3 3 0 where four values of a0x, a0y, a1x, and a1y correspond to x component, y component of a main vector and x component, y component of a sub-vector, respectively, and the four colors are designated to No. 0 to No. 3.

Claim 3

The image forming apparatus according to claim 1 , wherein the toner images are recorded on a recording medium using an electrophotographic recording method.

Claim 4

The image forming apparatus according to claim 1 , including: an optical writing/reading device to form an electrostatic latent image by allowing beams from light sources to reflect on a polygon mirror and scanning a latent image carrying body, wherein a resolution of the optical writing/reading device in a sub-scanning direction is 600 dpi and the number (N) of the light sources used to form a single color toner image and the number (M) of reflection surfaces of a polygon mirror satisfy an equality: N×M=6.

Claim 5

An image forming apparatus for recording images, comprising: an image processing unit to create image data for output including toner image data on four colors of yellow, cyan, magenta, and black such that toner images have line-shaped periodic structures; and an image forming unit to form the toner images using coloring materials of the four colors and superposing the toner images on a recording medium, wherein the line-shaped periodic structures of the toner images of the four colors are determined based on a combination of periodic structures having screen ruling and screen angles specified in table 2 below: TABLE 2 No. ruling angles a0x a0y a1x a1y 0 180.3 33.7 3 2 3 −2 1 180.3 146.3 −3 2 3 2 2 189.7 108.4 −1 3 3 1 3 200.0 0.0 0 0 0 −3 where four values of a0x, a0y, a1x, and a1y correspond to x component, y component of a main vector and x component, y component of a sub-vector, respectively, and the four colors are designated to No. 0 to No. 3.

Claim 6

An image forming apparatus for recording images, comprising: an image processing unit to create image data for output including toner image data on four colors of yellow, cyan, magenta, and black such that toner images have line-shaped periodic structures; and an image forming unit to form the toner images using coloring materials of the four colors and superposing the toner images on a recording medium, wherein the line-shaped periodic structures of the toner images of the four colors are determined based on a combination of periodic structures having screen ruling and screen angles specified in table 2 below: TABLE 2 No. ruling angles a0x a0y a1x a1y 0 180.3 33.7 3 2 3 −2 1 180.3 146.3 −3 2 3 2 2 189.7 108.4 −1 3 3 1 3 200.0 0.0 0 0 0 −3 where four values of a0x, a0y, a1x, and a1y correspond to x component, y component of a main vector and x component, y component of a sub-vector, respectively, and the four colors are designated to No. 0 to No. 3.

Claim 7

The image forming apparatus according to claim 4 , wherein the toner images are recorded on a recording medium using an electrophotographic recording method.

Claim 8

The image forming apparatus according to claim 4 , including: an optical writing/reading device to form an electrostatic latent image by allowing beams from light sources to reflect on a polygon mirror and scanning a latent image carrying body, wherein a resolution of the optical writing/reading device in a sub-scanning direction is 600 dpi and the number (N) of the light sources used to form a single color toner image and the number (M) of reflection surfaces of a polygon mirror satisfy an equality: N×M=6.

Claim 9

An image forming method for recording images, comprising: forming toner images using four coloring materials of yellow, cyan, magenta, and black such that the toner images have line-shaped periodic structures; and superposing the toner images on a recording medium, wherein the line-shaped periodic structures of the toner images of the four colors are determined based on a combination of periodic structures having screen ruling and screen angles specified in table 3 below: TABLE 3 No. ruling angles a0x a0y a1x a1y 0 180.3 33.7 3 2 3 −2 1 180.3 146.3 −3 2 3 2 2 200.0 0.0 3 0 0 −3 3 200.0 90.0 0 3 3 0 where four values of a0x, a0y, a1x, and a1y correspond to x component, y component of a main vector and x component, y component of a sub-vector, respectively, and the four colors are designated to No. 0 to No. 3.

Claim 10

An image forming method for recording images, comprising: forming toner images using four coloring materials of yellow, cyan, magenta, and black such that the toner images have line-shaped periodic structures; and superposing the toner images on a recording medium, wherein the line-shaped periodic structures of the toner images of the four colors are determined based on a combination of periodic structures having screen ruling and screen angles specified in table 3 below: TABLE 3 No. ruling angles a0x a0y a1x a1y 0 180.3 33.7 3 2 3 −2 1 180.3 146.3 −3 2 3 2 2 200.0 0.0 3 0 0 −3 3 200.0 90.0 0 3 3 0 where four values of a0x, a0y, a1x, and a1y correspond to x component, y component of a main vector and x component, y component of a sub-vector, respectively, and the four colors are designated to No. 0 to No. 3.

Claim 11

The image forming method according to claim 7 , wherein recording the toner images on a recording medium is performed using an electrophotographic recording method.