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US 7,733,363 B2Granted
Line head and image forming device using the same
AssigneeSeiko Epson Corporation
InventorsTakeshi Sowa, Yujiro Nomura, Ryuta Koizumi
Life of this patent
Estimating the term…
Abstract
A line head includes a lens array having a plurality of positive lens systems in a first direction. Each positive lens system has a pair of lenses with positive refractive power. A light emitter array disposed on an object side of the lens array has a plurality of light emitting elements disposed corresponding to the positive lens systems. An aperture plate forms an aperture stop on the object side of the pair of lenses. A focal distance f1 of one of the pair of lenses disposed on the object side satisfies the conditional formula f1≦d0/(1+W0/D1).
Claims8
A line head comprising:
- a lens array having a positive lens system in a first direction, the positive lens system having a pair of lenses with positive refractive power;
- a light emitter array disposed on an object side of the lens array and having a plurality of light emitting elements disposed corresponding to the positive lens system;
- and
- an aperture plate forming an aperture stop on the object side of the pair of lenses,
- wherein where f1 denotes a focal distance of one of the pair of lenses disposed on the object side, the following conditional formula is satisfied:
- f1≦d0/(1+W0/D1)
- where d0 denotes a distance between the light emitter array and a front principal surface of the lens on the object side;
- W0 denotes a distance between light emitting elements located at both ends of the plurality of light emitting elements disposed corresponding to the positive lens system in the first direction;
- and D1 denotes an effective diameter of the lens on the object side.
6 more elements
A line head comprising:
- a lens array having a positive lens system in a first direction, the positive lens system having a pair of lenses with positive refractive power;
- a light emitter array disposed on an object side of the lens array and having a plurality of light emitting elements disposed corresponding to the positive lens system;
- and
- an aperture plate forming an aperture stop on the object side of or between the pair of lenses,
- wherein where f1 denotes a focal distance of one of the pair of lenses disposed on the object side, the following conditional formula is satisfied:
- f1≦d0/(1+W0/D1)
- where d0 denotes a distance between the light emitter array and a front principal surface of the lens on the object side;
- W0 denotes a distance between light emitting elements located at both ends of the plurality of light emitting elements disposed corresponding to the positive lens system in the first direction;
- and D1 denotes an effective diameter of the lens on the object side.
6 more elements
An image forming device comprising:
- a latent image holding member;
- a charging section for charging the latent image holding member;
- a development section that develops the latent image holding member;
- a line head including a lens array having
- a positive lens system in a first direction, the positive lens system having a pair of lenses with positive refractive power,
- a light emitter array disposed on an object side of the lens array and having a plurality of light emitting elements disposed corresponding to the positive lens system, and
- an aperture plate forming an aperture stop on the object side of or between the pair of lenses,
- satisfying the following conditional formula where f1 denotes a focal distance of one of the pair of lenses disposed on the object side:
- f1≦d0/(1+W0/D1)
- where d0 denotes a distance between the light emitter array and a front principal surface of the lens on the object side;
- W0 denotes a distance between light emitting elements located at both ends of the plurality of light emitting elements disposed corresponding to the positive lens system in the first direction;
- and D1 denotes an effective diameter of the lens on the object side.
9 more elements
Dependencies are inferred from the claim text.