Line head and image forming apparatus using the same

• US 8,194,106 B2
• Filed: 10/21/2009
• Issued: 06/05/2012
• Est. Priority Date: 08/04/2006
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Nomura, Yujiro, Inoue, Nozomu, Koizumi, Ryuta, Ikuma, Ken
• Primary Examiner(s): TRAN, HUAN HUU
• Application Number:
  US12/603,424
• Publication Number:
  US 20100039489A1
• Time in Patent Office: 958 Days
• Field of Search: 347/129, 347/130, 347/224, 347/225, 347/238, 347/241, 347/244, 347/256, 347/258
• US Class Current: 347/130
• CPC Class Codes: B41J 2/45 using light-emitting diode [LED] or laser arrays
• CPC Class Codes: G03G 15/04072 by laser
• CPC Class Codes: G03G 15/326 by application of light, e.g. using a LED array
• CPC Class Codes: G03G 2215/0407 Light-emitting array or panel
• CPC Class Codes: G03G 2215/0451 Light-emitting array or panel

Abstract

A line head includes multiple light emitting element groups each including multiple light emitting elements. In each light emitting element group, the multiple light emitting elements are disposed in a two-dimensional arrangement so that a distance Gx is greater than a distance Gy. The light emitting element groups are arranged so that pitches Px are greater than pitches Py.

Claims

1. A line head comprising:

multiple light emitting element groups each including multiple light emitting elements; and

multiple imaging lenses which are disposed in association with the light emitting element groups, wherein

k light emitting elements (k is a natural number which is equal to or larger than

     2) are arranged at first pitches Δ

e along a first direction in each one of the light emitting element groups, and the light emitting element groups are disposed at second pitches Δ

g along the first direction,

each one of the multiple imaging lenses converges light beams from the light emitting elements and forms spots along the first direction on a surface-to-be-scanned which is transported in a second direction, and

the absolute value h of the optical magnification of the imaging lenses, the first pitch AΔ and

the second pitch Δ

g are related to each other so as to satisfy the formula below;

Δ

g−

(k−

1)·

Δ

e·

h<

Δ

e·

h.

2. The line head of claim 1, wherein the absolute value of the optical magnification of the imaging lenses is greater than 1.

3. An image forming apparatus comprising:

a latent image carrier;

multiple light emitting element groups each including multiple light emitting elements; and

multiple imaging lenses which are disposed in association with the light emitting element groups, wherein

k light emitting elements (k is a natural number which is equal to or larger than

     2) are arranged at first pitches Δ

e along a first direction in each one of the light emitting element groups, and the light emitting element groups are disposed at second pitches Δ

g along the first direction,

each one of the multiple imaging lenses converges light beams from the light emitting elements and forms spots along the first direction on a surface-to-be-scanned which is transported in a second direction, and

the absolute value h of the optical magnification of the imaging lenses, the first pitch Δ

e and the second pitch Δ

g are related to each other so as to satisfy the formula below;

Δ

g−

(k−

1)·

Δ

e·

h<

Δ

e·

h.