Sheet transport apparatus and image forming apparatus including the same

• US 7,474,872 B2
• Filed: 09/13/2005
• Issued: 01/06/2009
• Est. Priority Date: 09/16/2004
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Nojima, Koji
• Primary Examiner(s): Colilla; Daniel J
• Assistant Examiner(s): Primo; Allister
• Application Number:
  US11/225,274
• Publication Number:
  US 20060056860A1
• Time in Patent Office: 1,211 Days
• Field of Search: 271 314- 318, 271/4.01, 271/4.02, 271/4.03, 271/4.08, 271/10.01, 271/10.02, 271/10.03, 271/10.04, 271/10.05, 399/16, 399/18, 399/388, 399/405
• US Class Current: 399/388
• CPC Class Codes: G03G 15/6564 with correct timing of sheet feeding
• CPC Class Codes: G03G 15/6567 for deskewing or aligning

Abstract

A sheet transport apparatus includes a pair of rollers for transporting a sheet and a sheet detection device for detecting the sheet transported by the pair of rollers. The sheet detection device includes a flag that is displaceable when urged by the sheet transported by the pair of rollers and a single-chip acceleration sensor attached to the flag to detect the arrival of the sheet. When the sheet is brought into contact with the flag to rotate the flag, the acceleration sensor detects the roll acceleration of the flag so as to determine the timing of stopping the pair of rollers on the basis of a detection signal.

Claims

1. A sheet transport apparatus comprising:

a sheet transport unit configured to transport a sheet; and

a sheet detection unit configured to detect the sheet transported by the sheet transport unit, the sheet detection unit including a displacement member displaceable when urged by the sheet transported by the sheet transport unit and a single-chip sheet detection sensor attached to the displacement member and configured to detect the arrival of the sheet,

wherein the displacement member is disposed so that the length direction of the displacement member is perpendicular to a transport surface of the sheet and the displacement member is tilted when urged by the sheet.

2. The sheet transport apparatus according to claim 1, further comprising a control unit controlling the sheet transport unit based on detection from the sheet detection sensor.

3. The sheet transport apparatus according to claim 2, further comprising a transmission unit configured to wirelessly transmit a sheet detection signal of the sheet detection sensor to the control unit.

4. The sheet transport apparatus according to claim 1, wherein the sheet detection unit includes a plurality of displacement members arranged along the width direction of the transported sheet.

5. The sheet transport apparatus according to claim 4, wherein the displacement members have different lengths in the length direction thereof.

6. The sheet transport apparatus according to claim 1, wherein the displacement member includes a tilting member that is elastically flexible.

7. The sheet transport apparatus according to claim 1, wherein a plurality of sheet detection sensors are attached to the displacement member along the length direction of the displacement member.

8. The sheet transport apparatus according to claim 4, wherein a plurality of sheet detection sensors are attached to the displacement member along the length direction of the displacement member.

9. The sheet transport apparatus according to claim 6, wherein a plurality of sheet detection sensors are attached to the displacement member along the length direction of the displacement member.

10. The sheet transport apparatus according to claim 1, wherein the sheet detection sensor includes an acceleration sensor configured to detect acceleration of the displacement member.

11. The sheet transport apparatus according to claim 4, wherein the sheet detection sensor includes an acceleration sensor configured to detect acceleration of the displacement member.

12. The sheet transport apparatus according to claim 6, wherein the sheet detection sensor includes an acceleration sensor configured to detect acceleration of the displacement member.

13. The sheet transport apparatus according to claim 1, wherein the sheet detection sensor includes a pressure sensor configured to receive the leading edge of the sheet so as to detect the arrival of the leading edge of the sheet.

14. The sheet transport apparatus according to claim 4, wherein the sheet detection sensor includes a pressure sensor configured to receive the leading edge of the sheet so as to detect the arrival of the leading edge of the sheet.

15. The sheet transport apparatus according to claim 6, wherein the sheet detection sensor includes a pressure sensor configured to receive the leading edge of the sheet so as to detect the arrival of the leading edge of the sheet.

16. The sheet transport apparatus according to claim 10, wherein the acceleration sensor comprises a detecting portion detecting the acceleration of the displacement member and an electrode externally transmitting an output signal from the detecting portion, and wherein the acceleration sensor is packaged as a chip device from a wafer on which the detecting portion and the electrode are formed by a semiconductor manufacturing process.

17. The sheet transport apparatus according to claim 11, wherein the acceleration sensor comprises a detecting portion detecting the acceleration of the displacement member and an electrode externally transmitting an output signal from the detecting portion, and wherein the acceleration sensor is packaged as a chip device from a wafer on which the detecting portion and the electrode are formed by a semiconductor manufacturing process.

18. The sheet transport apparatus according to claim 12, wherein the acceleration sensor comprises a detecting portion detecting the acceleration of the displacement member and an electrode externally transmitting an output signal from the detecting portion, and wherein the acceleration sensor is packaged as a chip device from a wafer on which the detecting portion and the electrode are formed by a semiconductor manufacturing process.

19. The sheet transport apparatus according to claim 13, wherein the pressure sensor comprises a detecting portion detecting the pressure of the leading edge of the sheet urging against the detecting portion and an electrode externally transmitting an output signal from the detecting portion, and wherein the pressure sensor is packaged as a chip device from a wafer on which the detecting portion and the electrode are formed by a semiconductor manufacturing process.

20. The sheet transport apparatus according to claim 14, wherein the pressure sensor comprises a detecting portion detecting the pressure of the leading edge of the sheet urging against the detecting portion and an electrode externally transmitting an output signal from the detecting portion, and wherein the pressure sensor is packaged as a chip device from a wafer on which the detecting portion and the electrode are formed by a semiconductor manufacturing process.

21. The sheet transport apparatus according to claim 15, wherein the pressure sensor comprises a detecting portion detecting the pressure of the leading edge of the sheet urging against the detecting portion and an electrode externally transmitting an output signal from the detecting portion, and wherein the pressure sensor is packaged as a chip device from a wafer on which the detecting portion and the electrode are formed by a semiconductor manufacturing process.

22. An image forming apparatus comprising:

a sheet transport unit configured to transport a sheet;

a sheet detection unit detecting the sheet transported by the sheet transport unit; and

an image forming unit configured to form an image on the sheet transported by the sheet transport unit,

wherein the sheet detection unit includes a displacement member displaceable when urged by the sheet transported by the sheet transport unit and a single-chip sheet detection sensor attached to the displacement member and configured to detect arrival of the sheet, and the displacement member is disposed so that the length direction of the displacement member is perpendicular to a transport surface of the sheet and the displacement member is tilted when urged by the sheet.

23. The image forming apparatus according to claim 22, wherein the sheet detection sensor includes an acceleration sensor configured to detect acceleration of the displacement member.

24. The image forming apparatus according to claim 23, wherein the acceleration sensor comprises a detecting portion detecting the acceleration of the displacement member and an electrode externally transmitting an output signal from the detecting portion, and wherein the acceleration sensor is packaged as a chip device from a wafer on which the detecting portion and the electrode are formed by a semiconductor manufacturing process.