US 6,674,454 B2Granted

Color image forming apparatus

AssigneeSeiko Epson Corporation

InventorYujiro Nomura

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Abstract

Image carriers are arranged so as to satisfy an expression; −Ts/2<t1+t2−t3−nTp<Ts/2. “Ts” is a time period of scanning performed by each of scanning surfaces of a rotary polygon mirror. “Tp” is a time period of one rotation of the polygon mirror. “t1” is a time period required for a first image formed on a first image carrier among the image carriers is transferred to the transferred object at a first transferring position. “t2” is a time period required for the first image is traveled from the first transferring position to a second transferring position at which a second image formed on a second image carrier adjacent to the first image carrier at a downstream of the transporting path is transferred to the transferred object. “t3” is a time period required for the second image formed on the second image carrier is transferred to the transferred object at the second transferring position. “n” is a natural number.

Claims6

Dependent claims

A color image forming apparatus, comprising:

a transporting path, through which a recording medium is transported;
a plurality of rotary image carriers, arranged in the transporting path;
wherein
at least one rotary polygon mirror, which rotates to reflect light so as to scan an outer peripheral surface of each of the image carriers in a first direction when each of the image carriers is rotated in a second direction perpendicular to the first direction, so that a monochrome latent image is formed on the outer peripheral surface of each of the image carriers to be developed and superimposedly transferred onto a transferred object to form a color image thereon,
wherein the image carriers are arranged so as to satisfy the following expression:
−Ts/2<t1+t2−t3−nTp<Ts/2
where Ts is a time period of scanning performed by each of reflecting surfaces of the polygon mirror;
Tp is a time period of one rotation of the polygon mirror;
t1 is a time period required for a first latent image formed on a first image carrier among the image carriers is developed and transferred to the transferred object at a first transferring position;
t2 is a time period required for the first image is traveled from the first transferring position to a second transferring position at a downstream of the transporting path;
t3 is a time period required for a second latent image formed on a second image carrier adjacent to the first image carrier is developed and transferred to the transferred object at the second transferring position;
and
n is a natural number.

10 more elements

A color image forming apparatus, comprising;

a transporting path, through which a recording medium is transported;
a plurality of rotary image carriers, arranged in the transporting path;
wherein
at least one rotary polygon mirror, which rotates to reflect light so as to scan an outer peripheral surface of each of the image carriers in a first direction when each of the image carriers is rotated in a second direction perpendicular to the first direction, so that a monochrome latent image is formed on the outer peripheral surface of each of the image carriers to be developed and superimposedly transferred onto a transferred object to form a color image thereon,
wherein the image carriers are arranged so as to satisfy the following expression;
|t1+t2−t3−nTp|<[(Np/2)−0.5]Tp/Np
where Np is the number of reflecting surfaces of the polygon mirror which is an even number not less than 4;
Ts is a time period of scanning performed by each of the reflecting surfaces of the polygon mirror;
Tp is a time period of one rotation of the polygon mirror;
t1 is a time period required for a first latent image formed on a first image carrier among the image carriers is developed and transferred to the transferred object at a first transferring position;
t2 is a time period required for the first image is traveled from the first transferring position to a second transferring position at a downstream of the transporting path;
t3 is a time period required for a second latent image formed on a second image carrier adjacent to the first image carrier is developed and transferred to the transferred object at the second transferring position;
and
n is a natural number.

11 more elements

A color image forming apparatus, comprising:

a transporting path, through which a recording medium is transported;
a plurality of rotary image carriers, arranged in the transporting path;
wherein
at least one rotary polygon mirror, which rotates to reflect light so as to scan an outer peripheral surface of each of the image carriers in a first direction when each of the image carriers is rotated in a second direction perpendicular to the first direction, so that a monochrome latent image is formed on the outer peripheral surface of each of the image carriers to be developed and superimposedly transferred onto a transferred object to form a color image thereon,
wherein the image carriers are arranged so as to satisfy the following expression;
|t1+t2−t3−nTp|<[(Np/2)−1]Tp/Np
where Np is the number of reflecting surfaces of the polygon mirror which is an odd number not less than 3;
Ts is a time period of scanning performed by each of the reflecting surfaces of the polygon mirror;
Tp is a time period of one rotation of the polygon mirror;
t1 is a time period required for a first latent image formed on a first image carrier among the image carriers is developed and transferred to the transferred object at a first transferring position;
t2 is a time period required for the first image is traveled from the first transferring position to a second transferring position at a downstream of the transporting path;
t3 is a time period required for a second latent image formed on a second image carrier adjacent to the first image carrier is developed and transferred to the transferred object at the second transferring position;
and
n is a natural number.

11 more elements

Dependencies are inferred from the claim text.