Image-forming device

Claim 2

The image forming apparatus as set forth in claim 1, wherein each of said light emitting portions (21a) of said semiconductor laser array (21) has an optical axis substantially perpendicular to the surface of said device substrate (22).

Claim 3

The image forming apparatus as set forth in claim 2, wherein each of said light emitting portions of said semiconductor laser array (21) comprises: a pair of reflecting mirrors (23 and 28) with different reflectances disposed on the surface of said device substrate (22); an optical resonator disposed midway between said reflecting mirror (23 and 28) and having a plurality of semiconductor layers including a column shape clad layer (26); and a group II-VI compound semiconductor epitaxial layer (32) embedded in the periphery of said column shape clad layer (26).

Claim 4

The image forming apparatus as set forth in claim 3, wherein said group II-VI compound semiconductor epitaxial layer (32) contains two, three, or four elements selected from both group II elements Zn, Cd, and Hg and group VI elements O, S, Se, and Te.

Claim 5

The image forming apparatus as set forth in claim 3, wherein the lattice constant of said group II-VI compound semiconductor epitaxial layer (32) accords with the lattice constant of each of said semiconductor layers (24, 25, and 26).

Claim 6

The image forming apparatus as set forth in claim 3, wherein said column shape clad layer (26) is formed by a separation groove disposed in said semiconductor layers; and wherein said group II-VI compound semiconductor epitaxial layer (32) is embedded in said separation groove, said multiple semiconductor layers having an active layer (25) disposed below said separation groove, so as to synchronize the phase of light of each of said optical resonators.

Claim 7

The image forming apparatus as set forth in claim 6, wherein a laser beam emitted from each of said light emitting portions (21a) of said semiconductor laser array (21) is linearly polarized light, the cross section perpendicular to the optical axis of said laser beam being in an elliptic shape, the direction of the plane of polarization of said laser beam being different from both the directions of the major axis and minor axis of the ellipse.

Claim 8

The image forming apparatus as set forth in claim 6, wherein each of said light emitting portions (21a) of said semiconductor laser array (21) comprises a plurality of optical resonators with different planes of polarization.

Claim 9

The image forming apparatus as set forth in claim 1, wherein the spread angle of a laser beam emitted from each of said light emitting portions (21a) of said semiconductor laser array (21) is 20 degrees or less in full width at half maximum.

Claim 10

The image forming apparatus as set forth in claim 1, wherein a laser beam emitted from each of said light emitting portions (21a) of said semiconductor array (21) is entered into said deflecting unit (3), said laser beam being not collimated.

Claim 11

A laser beam scanning unit, comprising: a semiconductor laser array (21) having a plurality of light emitting portions (21a) for emitting laser beams, said light emitting portions (21a) being formed on a device substrate; and a deflecting unit (3) for deflecting the laser beams emitted from said light emitting portions (21a); wherein said light emitting portions (21a) are disposed two-dimensionally on a surface of said semiconductor laser array (21); and wherein the lighting and the amount of light of each of said light emitting portions (21a) are discretely controlled.

Claim 12

An image forming apparatus, comprising: a image bearing member (105) for forming a static latent image thereon; a charging unit (152) for charging the surface of said image bearing member (105); a laser beam scanning unit (153) for scanning a laser beam on the surface of said image bearing member (105) which is charged; and a developing unit (155) for causing a developing agent to adhere on the surface of said image bearing member (105) scanned with the laser beam; wherein said laser beam scanning unit (153) comprises: a semiconductor laser (121) having a light emitting portion (121a) for emitting a laser beam, said light emitting portion (121a) being formed on a device substrate (122); and a deflecting unit (103) for deflecting a laser beam emitted from said light emitting portion (121a) to the surface of said image bearing member (105); and wherein said light emitting portion (121a) has an optical axis substantially perpendicular to the surface of said device substrate (122).

Claim 13

The image forming apparatus as set forth in claim 12, wherein said light emitting portion (121a) of said semiconductor laser (121) comprises: a pair of reflecting mirrors (123 and 128) with different reflectances disposed on the surface of said device substrate (122); an optical resonator disposed midway between said reflecting mirror (123 and 128) and having a plurality of semiconductor layers including a column shape clad layer (126); and a group II-VI compound semiconductor epitaxial layer (132) embedded in the periphery of said column shape clad layer (126).

Claim 14

The image forming apparatus as set forth in claim 13, wherein said group II-VI compound semiconductor epitaxial layer (132) contains two, three, or four elements selected from both group II elements Zn, Cd, and Hg and group VI elements O, S, Se, and Te.

Claim 15

The image forming apparatus as set forth in claim 13, wherein the lattice constant of said group II-VI compound semiconductor epitaxial layer (132) accords with the lattice constant of each of said semiconductor layers (124, 125, and 126).

Claim 16

The image forming apparatus as set forth in claim 13, wherein said column shape clad layer (126) is formed by a separation groove disposed in said semiconductor layers; and wherein said group II-VI compound semiconductor epitaxial layer (132) is embedded in said separation groove, said multiple semiconductor layers having an active layer (125) disposed below said separation groove, so as to synchronize the phase of light of each of said optical resonators.

Claim 17

The image forming apparatus as set forth in claim 16, wherein a laser beam emitted from said light emitting portion (121a) of said semiconductor laser (121) is linearly polarized light, the cross section perpendicular to the optical axis of said laser beam being in an elliptic shape, the direction of the plane of polarization of said laser beam being different from both the directions of the major axis and minor axis of the ellipse.

Claim 18

The image forming apparatus as set forth in claim 16, wherein said light emitting portion (121a) of said semiconductor laser (121) comprises a plurality of optical resonators with different planes of polarization.

Claim 19

The image forming apparatus as set forth in claim 12, wherein the spread angle of a laser beam emitted from said light emitting portion (121a) of said semiconductor laser (121) is 20 degrees or less in full width at half maximum.

Claim 20

The image forming apparatus as set forth in claim 12, wherein a laser beam emitted from said light emitting portion (121a) of said semiconductor array (121) is entered into said deflecting unit (103), said laser beam being not collimated.

Claim 21

A laser beam scanning unit, comprising: a semiconductor laser (121) having a light emitting portion (121a) for emitting a laser beam, said light emitting portion being formed on a device substrate (122); and a deflecting unit (103) for deflecting said laser beam emitted from said light emitting portion (121a); wherein said light emitting portion (121a) has an optical axis substantially perpendicular to a surface of said device substrate (122).

Claim 22

An image forming apparatus, comprising: a image bearing member (205) for forming a static latent image thereon; a charging unit (252) for charging the surface of said image bearing member (205); a laser beam scanning unit for scanning a plurality of laser beams on the surface of said image bearing member (205) which is charged; and a developing unit (255) for causing a developing agent to adhere on the surface of said image bearing member (205) scanned with the laser beams; wherein said laser beam scanning unit (253), comprising: a semiconductor laser array (221) for emitting a plurality of laser beams; a collimator lens (202) for collimating each of said laser beams; a deflecting unit (218) for periodically deflecting the direction of each of said laser beams collimated by said collimator lens (202); and a scanning lens (204) for imaging each of said laser beams deflected by said deflecting unit (218) on said image bearing member (205); and wherein said deflecting unit (218) is a rotating mirror with one reflecting surface.

Claim 23

The image forming apparatus as set forth in claim 22, wherein said semiconductor laser array (221) has a plurality of light emitting portions (221a) two-dimensionally disposed on a device substrate; wherein each of said light emitting portions is adapted to emit a laser beam with an optical axis substantially perpendicular to a surface of said device substrate; and wherein the lighting and the amount of light of each of said light emitting portions (221a) are adapted to be discretely controlled.

Claim 24

The image forming apparatus as set forth in claim 22, wherein said scanning lens (204) and said collimator lens (202) have isotropic optical characteristics in their entire planes including their optical axes.

Claim 25

The image forming apparatus as set forth in claim 22, wherein the reflecting surface of said rotating mirror (218) is disposed in a manner such that the reflecting surface geometrically contains the rotating axis thereof; and wherein at least one center axis of said laser beams is reflected on the reflecting surface near the rotating axis thereon.

Claim 26

The image forming apparatus as set forth in claim 22, wherein an image spot (206) formed on said image bearing member (205) by said scanning lens (204) is in an elliptic shape whose minor axis is disposed in the scanning direction; and wherein the ratio of a spread angle of a laser beam emitted from said semiconductor laser array in the scanning direction and that in the direction perpendicular thereto is the reciprocal of the ratio of the longer diameter and shorter diameter of said image spot (206).

Claim 27

A laser beam scanning unit, comprising: a semiconductor laser array (221) for emitting a plurality of laser beams; a collimator lens (202) for collimating each of said laser beams; a deflecting unit (218) for periodically deflecting the direction of each of said laser beams collimated by said collimator lens (202); and a scanning lens (204) for forming the laser beam deflected by said deflecting unit (218) on a image bearing member (205); wherein said deflecting unit (218) is a rotating mirror having one reflecting surface.

Claim 28

An image forming apparatus, comprising: a image bearing member (305) for forming a static latent image thereon; a charging unit (352) for charging the surface of said image bearing member (305); a laser beam scanning unit for scanning a plurality of laser beams on the surface of said image bearing member (305) which is charged; and a developing unit (355) for causing a developing agent to adhere on the surface of said image bearing member (305) scanned with the laser beams; wherein said laser beam scanning unit (353), comprises: a semiconductor laser array (341) having a plurality of light emitting portions (341a) for emitting a plurality of laser beams; a collimator lens (302) for collimating each of said laser beams; a deflecting unit (303) for periodically deflecting the direction of each of said laser beams collimated by said collimator lens (302); and a scanning lens (304) for imaging each of said laser beams deflected by said deflecting unit (303) on said image bearing member (305); and wherein the following relation is satisfied fc/δmax > 25 where fc is the focal length of said collimator lens (302) and δmax is the distance between the mutually most spaced-apart two of said light emitting portions (341a) of said semiconductor laser array (341).

Claim 29

The image forming apparatus as set forth in claim 28, wherein the following relation is satisfied fc/δmax > 50 where fc is the focal length of said collimator lens (302) and δmax is the distance between the mutually most spaced-apart two of said light emitting portions (341a) of said semiconductor laser array (341).

Claim 30

The image forming apparatus as set forth in claim 26, wherein said light emitting portions (341a) of said semiconductor laser array (341) are disposed two-dimensionally on said device substrate (322); wherein each of said light emitting portions (341a) is adapted to emit a laser beam with an optical axis substantially perpendicular to a surface of said device substrate; and wherein the lighting and the amount of light of each of said light emitting portions are discretely controlled.

Claim 31

The image forming apparatus as set forth in claim 28, wherein said deflecting unit (303) is a rotating polygon mirror having a plurality of mirror surfaces disposed in a regular prism shape.

Claim 32

The image forming apparatus as set forth in claim 31, further comprising: tilt angle compensation optical systems (307 and 307') for optically compensating the deviation of a scanning line in a sub scanning direction due to a difference of a mutual tilt angle of each reflecting surface to a rotating axis of said rotating polygon mirror (303), said tilt angle compensation optical systems (307 and 307') being disposed on an optical path midway from said semiconductor laser array (341) to said image bearing member (305).

Claim 33

A laser beam forming apparatus, comprising: a semiconductor laser array (341) having a plurality of light emitting portions (341a) for emitting laser beams; a collimator lens (302) for collimating each of a plurality of laser beams; a deflecting unit (303) for periodically deflecting the direction of each of said plurality of laser beams collimated by said collimator lens (302); and a scanning lens (304) for imaging the laser beams deflected by said deflecting unit (303) on said image bearing member (305); wherein the following relation is satisfied fc/δmax > 50 where fc is the focal length of said collimator lens (302) and δmax is the distance between the mutually most spaced-apart two of said light emitting portions (341a) of said semiconductor laser array (341).

Claim 34

An image forming apparatus, comprising: a image bearing member (407) for forming a static latent image on a surface thereof; a charging unit (451) for charging the surface of said image bearing member (407); a laser beam scanning unit (452) for scanning a plurality of laser beams to the charged surface of said image bearing member (407); and a developing unit (453) for causing a developing agent to adhere on the surface of said image bearing member (407); wherein said laser beam scanning unit comprises: a plurality of light emitting portions (401a) adapted for emitting laser beams and disposed on a device substrate (422); and a deflecting unit (404) for deflecting the laser beams emitted from said light emitting portions; wherein the center axis of each laser beam emitted from said semiconductor laser array is substantially perpendicular to a surface of said device substrate (422); wherein an aperture stop (403) is disposed at a position where cross sections of the laser beams are matched at least partially, said position being on an optical path between said semiconductor laser array (401) and said deflecting unit (404); and wherein, provided that the strongest power of laser beams which has passed through said aperture stop is 1, the powers of the remaining laser beams are 0.9 or higher.

Claim 35

The image forming apparatus as set forth in claim 34 further comprising: an optical system composed of a single or a plurality of lenses and disposed midway between said semiconductor laser array (401) and said deflecting unit (404); wherein said aperture stop (403) is disposed at a position where center axes of said plurality of laser beams are intersected with an optical axis of said optical system.

Claim 36

A laser beam forming apparatus, comprising: a semiconductor laser array (401) having a plurality of light emitting portions for emitting laser beams, said light emitting portions being disposed on a device substrate (422); and a deflecting unit (404) for deflecting laser beams emitted from said light emitting portions (401a); wherein an aperture stop (403) is disposed at a position where cross sections of the laser beams are matched at least partially, said position being on an optical path between said semiconductor laser array (401) and said deflecting unit (404); and wherein, provided that the strongest power of laser beams which has passed through said aperture stop is l, the powers of the remaining laser beams are 0.9 or higher.

Claim 37

An image forming apparatus, comprising: a image bearing member (507) for forming a static latent image on a surface thereof; a charting unit (551) for charging the surface of said image bearing member (507); a laser beam scanning unit (552) for scanning a plurality of laser beams on the charged surface of said image bearing member (507); and a developing unit (553) for causing a developing agent to adhere on the scanned surface of said image bearing member (507); wherein said laser beam scanning unit comprises: a semiconductor laser array (501) having a plurality of light emitting portions for emitting laser beams; a collimator lens (502) for collimating laser beams emitted from said light emitting portions;, and a deflecting unit (504) for deflecting the laser beams; wherein an aperture stop (503) is disposed on an optical path midway between said semiconductor laser array (501) and said deflecting unit (504); and wherein the following relations are satisfied st f ≦ 0.12 ( D d ) 2.3 + 0.17 D d ≦ 2 where f is the focal length of said collimator lens (502); s is the distance between a deflecting unit (504) side focal point of said collimator lens (502) and said aperture stop (503); t is the distance between a light emitting portion spaced farthest from an optical axis of said collimator lens (502) and said optical axis; D is the diameter of said aperture stop (503); and d is the diameter of each of said collimated beam.

Claim 38

An image forming apparatus, comprising: a image bearing member (507) for forming a static latent image on a surface thereof; a charting unit (551) for charging the surface of said image bearing member (507); a laser beam scanning unit (552) for scanning a plurality of laser beams on the charged surface of said image bearing member (507); and a developing unit (553) for causing a developing agent to adhere on the scanned surface of said image bearing member (507); wherein said laser beam scanning unit comprises: a semiconductor laser array (501) having a plurality of light emitting portions for emitting laser beams; a collimator lens (502) for collimating laser beams emitted from said light emitting portions;, and a deflecting unit (504) for deflecting the laser beams; wherein an aperture stop (503) is disposed on an optical path midway between said semiconductor laser array (501) and said deflecting unit (504); and wherein the following relations are satisfied st f ≦ 0.06 ( D d ) 2.9 + 0.08 D d ≦ 2 where f is the focal length of said collimator lens (502); s is the distance between a deflecting unit (504) side focal point of said collimator lens (502) and said aperture stop (503); t is the distance between a light emitting portion spaced farthest from an optical axis of said collimator lens (502) and said optical axis; D is the diameter of said aperture stop (503); and d is the diameter of each of said collimated beam.

Claim 39

A laser beam scanning apparatus, comprising: a semiconductor laser array (501) having a plurality of light emitting portions for emitting laser beams; a collimator lens (502) for collimating the laser beams emitted from said light emitting portions; and a deflecting unit (504) for deflecting the laser beams; wherein an aperture stop (502) is disposed on an optical path midway between said semiconductor laser array (501) and said deflecting unit (504); and wherein the following relations are satisfied st f ≦ 0.12 ( D d ) 2.3 + 0.17 D d ≦ 2 where f is the focal length of said collimator lens (502); s is the distance between a deflecting unit (504) side focal point of said collimator lens (502) and said aperture stop (503); t is the distance between a light emitting portion spaced farthest from an optical axis of said collimator lens (502) and said optical axis; D is the diameter of said aperture stop (503); and d is the diameter of each of said collimated beam.

Claim 40

A laser beam scanning apparatus, comprising: a semiconductor laser array (501) having a plurality of light emitting portions for emitting laser beams; a collimator lens (502) for collimating the laser beams emitted from said light emitting portions; and a deflecting unit (504) for deflecting the laser beams; wherein an aperture stop (502) is disposed on an optical path midway between said semiconductor laser array (501) and said deflecting unit (504); and wherein the following relations are satisfied st f ≦ 0.06 ( D d ) 2.9 + 0.08 D d ≦ 2 where f is the focal length of said collimator lens (502); s is the distance between a deflecting unit (504) side focal point of said collimator lens (502) and said aperture stop (503); t is the distance between a light emitting portion spaced farthest from an optical axis of said collimator lens (502) and said optical axis; D is the diameter of said aperture stop (503); and d is the diameter of each of said collimated beam.