PAPER TRAY UNIT

Abstract

A paper tray unit includes a paper size sensor which is attached to a paper tray and determines a paper size in a paper width direction by detecting a position of a paper width guide. In the paper tray unit, a movable member moves in a paper feed direction accompanying movement of the paper width guide. The position of the paper width guide is detected by the paper size sensor detecting or not detecting the movable member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view illustrating an exterior of an image scanning device including an original document tray unit according to a first preferred embodiment of the present invention.

FIG. 2 is a schematic plan view illustrating a structure of a reverse surface of an original document tray unit.

FIG. 3 is a schematic plan view illustrating a structure of the reverse surface of the original document tray unit.

FIG. 4 is a schematic plan view illustrating a structure of the reverse surface of the original document tray unit.

FIG. 5 is a schematic plan view illustrating a structure of the reverse surface of the original document tray unit.

FIG. 6 is a schematic perspective view illustrating an attachment state of a rack member, a movable member, a pinion gear, and a paper size sensor.

FIG. 7 is a schematic plan view illustrating a structure of a reverse surface of an original document tray unit according to a second preferred embodiment of the present invention.

FIG. 8 is a schematic perspective view illustrating a reverse surface of an original document tray unit according to a conventional art.

FIG. 9 is a schematic perspective view illustrating an exterior of a paper size sensor according to a conventional art.

Claims

1. A paper tray unit comprising: a paper tray on which a paper to be fed into a paper transportation path is placed and in which a paper discharge port of the paper transportation path is provided directly under the paper tray;a paper width guide provided movably in a direction that is substantially perpendicular to a paper feed direction on an upper surface of the paper tray and arranged to position the paper in a paper width direction;a paper size sensor attached to a reverse surface of the paper tray and arranged to determine a size of the paper in the paper width direction by detecting a position of the paper width guide; anda movable member arranged to move in the paper feed direction accompanying the movement of the paper width guide.

2. The paper tray unit according to claim 1, wherein a height of the paper size sensor protruding from the reverse surface of the paper tray is within a range in which a paper discharged from the paper discharge port does not touch the paper size sensor.

3. The paper tray unit according to claim 2, wherein the paper size sensor is a transmissive optical sensor which emits a light beam across a detection groove through which the movable member passes.

4. The paper tray unit according to claim 3, wherein the paper size sensor has a maximum dimension in a height direction of the detection groove and is attached such that the height direction of the detection groove is substantially parallel to the paper tray unit.

5. The paper tray unit according to claim 4, wherein each of the paper width guide, the paper size sensor, and the movable member include a pair of paper width guides, a pair of paper size sensors, and a pair of movable members; the paper tray unit includes a pair of rack members integral with the pair of the paper width guides; and the pair of the movable members moves in a direction that is substantially perpendicular to a moving direction of the rack members in response to a movement of the rack members, and a paper size is determined by the pair of the paper size sensors detecting a position of the movable members.

6. The paper size sensor according to claim 5, wherein the pair of the paper width guides is integral with the pair of the rack members via a respective connecting member, and is slidable on the paper tray within a range in which the connecting member is guided along an elongated hole provided on the paper tray.

7. The paper tray unit according to claim 6, wherein the pair of the rack members includes a longitudinal flat plate member and a teethed portion provided at one side in a width direction of the flat plate member.

8. The paper tray unit according to claim 7, wherein a guide groove is provided along a longitudinal direction of each of the rack members, each guide groove is substantially semicircular in a longitudinal cross-section, and each guide groove has a different planar shape.

9. The paper tray unit according to claim 8, wherein the guide groove of a first rack member of the pair of rack members includes a first parallel portion and a second parallel portion extending parallel to the longitudinal direction of the first rack member, the first and the second parallel portions are displaced in a width direction of the first rack member, and a diagonal portion extending diagonally in the longitudinal direction of the first rack member is provided to connect the first parallel portion and the second parallel portion; and the guide groove of a second rack member of the pair of rack members includes a first parallel portion, a second parallel portion and a third parallel portion extending parallel to the longitudinal direction of the second rack member; and a first diagonal portion and a second diagonal portion extending diagonally in the longitudinal direction of the second rack member are provided to connect the first parallel portion, the second parallel portion, and the third parallel portion.

10. The paper tray unit according to claim 9, wherein a pinion gear is rotatably supported on the reverse surface of paper tray; and the pinion gear includes a gear main body and a substantially disk-shaped flange, the gear main body has a teethed portion formed around a circumference of a cylinder member, the flange is provided at one end of the gear main body and protrudes in a radial direction of the gear main body, and a boss inserting hole is provided through the gear main body and the flange.

11. The paper tray unit according to claim 10, wherein the teethed portions of the rack members and the teethed portion of the pinion gear are meshed with each other, and when the teethed portions of the rack members and the teethed portion of the pinion gear are meshed, the pair of the paper width guides move simultaneously in opposite directions.

12. The paper tray unit according to claim 11, wherein each of the movable members includes a longitudinal portion, a flat plate portion, a fitting projection, and a projecting detection portion; the longitudinal portion includes a longitudinal member, the flat plate portion laterally protrudes from one end of the longitudinal portion, the fitting projection protrudes from a top portion of the longitudinal portion and fits in the guide groove of the rack member, and the projecting detection portion is provided on an upper surface of the flat plate portion.

13. The paper tray unit according to claim 12, wherein a substantially V-shaped slide groove is provided on a bottom portion of the longitudinal portion of the movable member and extends in the longitudinal direction of the longitudinal portion.

14. The paper tray unit according to claim 13, wherein the pair of the paper size sensors includes snap-fits arranged to fit into sensor mounting portions provided on the reverse surface of the paper tray.

15. The paper tray unit according to claim 7, wherein the pair of the rack members includes a shaped cut-out portion arranged on an opposite side in the width direction of the flat plate member from the teethed portion.

16. The paper tray according to claim 15, wherein the cut-out portion on one of the pair of the rack members has a different planar shape from the cut-out portion on the other of the pair of rack members.

17. The paper tray unit according to claim 16, wherein the pair of the movable members include blade springs made of a bent metal plate, a base end portion of the movable members is attached to the reverse surface of the paper tray, and an intermediate portion of each of the movable members in a longitudinal direction contacts against a respective cut-out portion of the pair of the rack members.

18. The paper tray unit according to claim 17, wherein a pinion gear is rotatably supported on the reverse surface of the paper tray, the pinion gear including: a gear main body having a teethed portion arranged around a circumference of a cylinder member;a substantially disk-shaped flange provided at one end of the gear main body and protruding in a radial direction of the gear main body; anda boss inserting hole penetrating through the gear main body and the flange.

19. The paper tray unit according to claim 18, wherein the pair of the paper width guides are arranged to move by the teethed portion of the flat plate member meshing with the teethed portion disposed around the circumference of the cylinder member.

20. The paper tray according to claim 19, wherein the pair of the paper size sensors includes snap-fits arranged to fit into sensor mounting portions provided on the reverse surface of the paper tray.