Optical line sensor

Abstract

The present invention provides an optical line sensor that can effectively prevent stray light from entering each light-receiving element array. [Solution] Multiple light-receiving lenses 111 are arranged in a line along the main scanning direction and transmit light from the illuminated object. The aperture member 113 has multiple openings 113E through which the light transmitted through the multiple light-receiving lenses 111 passes. Multiple light-receiving elements constitute multiple light-receiving element arrays 12 that extend along the main scanning direction, corresponding to the multiple openings 113E. The multiple light-receiving element arrays 12 are arranged in a staggered pattern on two rows of reading lines L. Between the aperture member 113 and the multiple light-receiving element arrays 12, a light-shielding block 114 is provided to prevent light that has passed through an adjacent opening 113E from entering each light-receiving element array 12 with respect to the opening 113E corresponding to each light-receiving element array 12.

Claims

1. An optical line sensor that reads an object moving relative to it along the sub-scanning direction using a reading line extending in the main scanning direction, Multiple light-receiving lenses are arranged in a line along the main scanning direction and transmit light from the illuminated object, An aperture member having multiple openings through which light transmitted through the multiple light-receiving lenses passes, It comprises a plurality of light-receiving elements arranged in a line along the main scanning direction, which receive light that has passed through the plurality of apertures, The plurality of light-receiving elements constitute a plurality of light-receiving element arrays that correspond to the plurality of apertures and extend along the main scanning direction. The aforementioned array of multiple light-receiving elements is arranged in a staggered pattern on the two rows of the reading lines. An optical line sensor is provided between the aperture member and the plurality of light-receiving element arrays, which prevents light passing through an opening adjacent to the opening corresponding to each light-receiving element array from entering each light-receiving element array.

2. The optical line sensor according to claim 1, wherein the first light-shielding portions are provided in multiple locations corresponding to the plurality of apertures, and light passing through an aperture adjacent to an aperture corresponding to each light-receiving element array is blocked by the first light-shielding portions provided in relation to the adjacent apertures.

3. The optical line sensor according to claim 2, wherein a plurality of the first light-shielding portions are arranged in a staggered pattern on two rows of reading lines.

4. The optical line sensor according to claim 2, wherein the width of the first light-shielding portion in the main scanning direction is greater than or equal to the field of view width at the installation position of the first light-shielding portion in the adjacent aperture to which the first light-shielding portion is associated, and less than or equal to the width of the light-receiving element array.

5. The optical line sensor according to claim 1, wherein the first light-shielding portion has a through-hole that extends along the optical path of light passing through the opening and incident on the light-receiving element array corresponding to the opening.

6. The plurality of openings are located between the two rows of reading lines when viewed from a direction perpendicular to the main scanning direction and the sub-scanning direction. The optical line sensor according to claim 5, wherein the through-hole is formed in a tapered shape that is inclined in the sub-scanning direction with respect to the direction perpendicular to the main scanning direction and the sub-scanning direction.

7. The optical line sensor according to claim 6, wherein the through-hole extends in a stepped manner along the direction of inclination of the through-hole.

8. The optical line sensor according to claim 1, wherein each of the plurality of light-receiving lenses constitutes a telecentric optical system, and the width of each light-receiving lens in the sub-scanning direction is smaller than the width in the main scanning direction.

9. The optical line sensor according to claim 1, wherein the plurality of apertures are formed in the shape of a frustocone.

10. The optical line sensor according to claim 1, wherein the aperture member has a plurality of pinholes into which light passing through the plurality of openings is incident, and these pinholes are formed opposite each other at intervals from each opening.

11. The optical line sensor according to claim 9 or 10, wherein the aperture member has a second light-shielding portion formed therein that blocks a part of the opening to prevent stray light from entering.

12. The aperture member consists of a plurality of aperture members, each having the opening formed therein. A pair of holding plates that sandwich at least two of the plurality of light-receiving lenses and at least one of the plurality of aperture members in the sub-scanning direction, The system further comprises a pair of sensor holders that sandwich a plurality of light-receiving lens arrays, arranged in the main scanning direction, in the sub-scanning direction, with the pair of holding plates, the at least two light-receiving lenses sandwiched between the pair of holding plates, and the at least one aperture member forming a single light-receiving lens array. The optical line sensor according to claim 1, wherein one of the pair of retaining plates is positioned on one of the pair of sensor holders by a first positioning member, the other of the pair of retaining plates is positioned on the other of the pair of sensor holders by a second positioning member, and the pair of sensor holders are connected to each other so that the pair of retaining plates are positioned facing each other in the sub-scanning direction.

13. Each of the pair of retaining plates has a fixing screw hole formed therein. Each of the pair of sensor holders has a through hole formed in a position opposite to the fixing screw hole. The optical line sensor according to claim 12, wherein a first fixing screw, inserted through a through hole formed in one of the pair of sensor holders, is screwed into a fixing screw hole formed in one of the pair of retaining plates, thereby fixing one of the pair of retaining plates to one of the pair of sensor holders, and a second fixing screw, inserted through a through hole formed in the other of the pair of sensor holders, is screwed into a fixing screw hole formed in the other of the pair of retaining plates, thereby fixing the other of the pair of retaining plates to the other of the pair of sensor holders.

14. The optical line sensor according to claim 12, further comprising a spacer disposed between the pair of sensor holders, for maintaining a constant distance between the pair of sensor holders when the plurality of light-receiving lens arrays are sandwiched between the pair of sensor holders in the sub-scanning direction.

15. The light-receiving substrate further comprises the aforementioned plurality of light-receiving elements mounted on it. Each of the pair of sensor holders is formed in an L-shape, having a first plate portion facing the plurality of light-receiving lens arrays and a second plate portion extending from one end of the first plate portion toward the side opposite to the plurality of light-receiving lens arrays. The optical line sensor according to claim 12, wherein the light-receiving substrate is mounted so as to straddle the pair of sensor holders on the second plate side.

16. The optical line sensor according to claim 12, wherein the optical axes of the plurality of light-receiving lenses are located on the center line between the two rows of reading lines.

17. The optical line sensor according to claim 12, wherein a plurality of the aforementioned pairs of sensor holders are arranged in a row in the main scanning direction.

18. The optical line sensor according to claim 12, further comprising a third light-shielding portion that covers the gap between adjacent aperture members.

19. The optical line sensor according to claim 12, further comprising a cover member provided so as to span the end faces on the light incidence side of the pair of holding plates.

20. The pair of retaining plates has at least one injection hole formed at a position facing the light-receiving lens. The optical line sensor according to claim 12, wherein the pair of retaining plates and the at least two light-receiving lenses are fixed by an adhesive injected into the at least one injection hole.

21. The pair of retaining plates has at least one first adjustment screw hole formed in a position facing the light-receiving lens. The optical line sensor according to claim 12, wherein the angle of the light-receiving lens relative to the pair of retaining plates can be adjusted by a first adjustment screw that is screwed into at least one first adjustment screw hole and whose tip contacts the light-receiving lens.

22. The pair of sensor holders has at least one second adjustment screw hole formed in a position facing the retaining plate, The optical line sensor according to claim 12, wherein the angle of the retaining plate relative to the pair of sensor holders can be adjusted by a second adjustment screw that is screwed into at least one second adjustment screw hole and whose tip abuts against the retaining plate.

23. The optical line sensor according to claim 12, wherein the pair of retaining plates have a fitting portion for fitting together and connecting the pair of retaining plates.

Images