Duplex automatic sheet feeder

Abstract

In a duplex automatic sheet feeder, a first passageway is connected to a sheet input tray for storing sheets. A sheet feeding mechanism feeds the sheets one by one to the first passageway. A second passageway is connected to the first and third passageways and has an image processing region. A fourth passageway is connected to the third passageway and the second passageway. A fifth passageway is connected to the third passageway and a duplex sheet output tray. A guiding mechanism located at a connection portion between the third and fifth passageways selectively guides the sheet from the third passageway to the fifth passageway. A sheet detector located at the third passageway detects the sheet moving through the third passageway. A transporting mechanism transports the sheet from the first passageway to the duplex sheet output tray sequentially through the second, third, fourth, third and fifth passageways.

Description

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a duplex automatic sheet feeder, and more particularly to a duplex automatic sheet feeder capable of effectively preventing an ultra-thin sheet from buckling in a sheet passageway.

2. Related Art

In a conventional duplex scanner, an automatic sheet feeder usually has to turn a document thrice and transport the document through a scanning region thrice when the document is being scanned. When the document is transported across the scanning region at the first time, a front side of the document is scanned. When the document is transported across the scanning region at the second time, a backside of the document is scanned. When the document is transported across the scanning region at the third time, no scanning operation is carried out. The third document transporting operation is, carried out in order to keep the same order of the documents.

Thus, a next document cannot be fed until the current document is transported across the scanning region at the third time in each scan procedure. A lot of unessential waiting time is wasted so that the scanning operation cannot be carried rapidly in this conventional automatic sheet feeder.

In addition, many branch passageways are formed on the document transporting path for the purpose of turning over the sheet smoothly. In order to make the document travelling path become unidirectional, an elastic Mylar has to be disposed at the branching portion. The elastic Mylar may be pushed away by the sheet moving in a first direction, and guides the sheet, which is moving in a direction opposite to the first direction, to another branch passageway. In this case, when the sheet is too thin to have the sufficient rigidity, the sheet cannot push the elastic Mylar away and may buckle and be jammed in the passageway.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a duplex automatic sheet feeder capable of effectively preventing an ultra-thin sheet from buckling in a sheet passageway.

To achieve the above-identified object, the invention provides a duplex automatic sheet feeder including a sheet input tray, a first passageway, a sheet feeding mechanism, a second passageway, a third passageway, a fourth passageway, a fifth passageway, a sheet output tray, a guiding mechanism, a sheet detector and a transporting mechanism. The sheet input tray stores a plurality of sheets. The first passageway is connected to the sheet input tray. The sheet feeding mechanism feeds the sheets one by one to the first passageway. The second passageway is connected to the first passageway and has an image processing region. The third passageway is connected to the second passageway. The fourth passageway is connected to the third passageway and the second passageway. The fifth passageway is connected to the third passageway. The sheet output tray is connected to the fifth passageway. The guiding mechanism is located at a connection portion between the third passageway and the fifth passageway, and is for selectively guiding the sheet from the third passageway to the fifth passageway. The sheet detector is located at the third passageway and is for detecting the sheet moving through the third passageway. The transporting mechanism is for transporting the sheet from the first passageway to the sheet output tray sequentially through the second passageway, the third passageway, the fourth passageway, the second passageway, the third passageway and the fifth passageway.

Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a schematic illustration showing a duplex automatic sheet feeder according to a first embodiment of the invention;

FIG. 2 is a schematic illustration showing a duplex automatic sheet feeder according to a second embodiment of the invention;

FIG. 3 is a schematic illustration showing a duplex automatic sheet feeder according to a third embodiment of the invention;

FIG. 4 is a schematic illustration showing a duplex automatic sheet feeder according to a fourth embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.

FIG. 1 is a schematic illustration showing a duplex automatic sheet feeder 1 according to a first embodiment of the invention. Referring to FIG. 1, the duplex automatic sheet feeder 1 of this embodiment includes a sheet input tray 10, a first passageway 21 (from points A to B), a sheet feeding mechanism 30, a second passageway 22 (from points B to C), a third passageway 23 (from points C to 23A), a fourth passageway 24 (from points C to B), a fifth passageway 25, a sheet output tray 40, a guiding mechanism 50, an elastic guide 52, a sheet detector 60 and a transporting mechanism 70.

The sheet input tray 10 stores a plurality of sheets S. In this embodiment, the uppermost sheet is first fed. The first passageway 21 is connected to the sheet input tray 10. The sheet feeding mechanism 30 feeds the sheets S one by one to the first passageway 21. In this embodiment, the sheet feeding mechanism 30 includes a pickup roller 31 and a separation roller set 32.

The second passageway 22 is connected to the first passageway 21 and has an image processing region 22A. In this embodiment, the image processing region 22A is a scanning region, and a sheet (document or original) moving across this region is scanned by an optical module 90. In another embodiment, the image processing region 22A is a printing region, and a printing module prints data on a sheet moving across this region.

The third passageway 23 is connected to the second passageway 22 so that the sheet can enter the third passageway 23 from the second passageway 22. The fourth passageway 24 is connected to the third passageway 23 and the second passageway 22, and the sheet coming from the third passageway 23 can enter the fourth passageway 24 but cannot enter the second passageway 22. The fifth passageway 25 is connected to the third passageway 23 so that the sheet coming from the third passageway 23 can enter the fifth passageway 25.

The sheet output tray 40 is connected to the fifth passageway 25 and stores the sheets after being scanned. The guiding mechanism 50 may swing and is located at a connection portion 26 between the third passageway 23 and the fifth passageway 25 to selectively guide the sheet S from the third passageway 23 to the fifth passageway 25. The elastic guide 52 guides the sheet S from the third passageway 23 to the fourth passageway 24, prevents the sheet S coming from the third passageway 23 from entering the second passageway 22, and allows the sheet S to enter the third passageway 23 from the second passageway 22. The sheet detector 60 located at the third passageway 23 is for detecting the sheet S moving through the third passageway 23. The sheet detector 60 may be a reflective or transmissive detector and outputs an infrared light ray, for example, to detect whether a leading edge or a trailing edge of the sheet has passed through a specific position to serve as a reference for feeding another sheet.

The transporting mechanism 70 includes a plurality of rollers 71 to 79. In a duplex scan mode, the transporting mechanism 70 transports the sheet S from the first passageway 21 to the duplex sheet output tray 40 sequentially through the second passageway 22, the third passageway 23, the fourth passageway 24, the second passageway 22, the third passageway 23 and the fifth passageway 25. When the sheet enters the third passageway 23 from the second passageway 22, the elastic guide 52 is slightly pushed away by the sheet, and the state of the guiding mechanism 50 is shown by the dashed line profile. When the sheet enters the fourth passageway 24 from the third passageway 23, the state of the guiding mechanism 50 is shown by the dashed line profile, and the elastic guide 52 is in close contact with the connection portion 26. Thus, the elastic guide 52 can guide the sheet S from the third passageway 23 to the fourth passageway 24. When the sheet enters the fifth passageway 25 from the third passageway 23, the state of the guiding mechanism 50 is shown by the solid line profile.

In this embodiment, the third passageway 23 is also connected to the sheet output tray 40. In a simplex scan mode, the transporting mechanism 70 may further transport the sheet S from the first passageway 21 to the sheet output tray 40 sequentially through the second passageway 22 and the third passageway 23. An outlet 23A of the third passageway 23 is farther from the sheet output tray 40 than an outlet 25A of the fifth passageway 25.

FIG. 2 is a schematic illustration showing a duplex automatic sheet feeder according to a second embodiment of the invention. Referring to FIG. 2, the duplex automatic sheet feeder according to this embodiment further includes a simplex sheet output tray 80, which is connected to the third passageway 23, for transporting the sheet S from the first passageway 21 to the simplex sheet output tray 80 sequentially through the second passageway 22 and the third passageway 23 in a simplex mode. In this embodiment, the simplex sheet output tray 80 is located at a level higher than the sheet output tray 40. Consequently, the user may identify whether the documents or sheets have been processed in a desired simplex or duplex manner according to the tray in which the documents or sheets are placed.

It is to be noted that the elastic guide 52 may be replaced with a sub-guiding mechanism (not shown), which is similar to the guiding mechanism 50 and may swing, for guiding the sheet S from the third passageway 23 to the fourth passageway 24 and guiding the sheet S from the second passageway 22 to the third passageway 23. Because the sub-guiding mechanism is similar to the guiding mechanism 50 and the position thereof is the same as that of the elastic guide 52, the detailed arrangement thereof will be omitted.

In addition, in order to shorten the time of continuously transporting the sheets, the second sheet can be fed into the first passageway 21 after the second side of the first sheet is scanned and after the trailing edge of the first sheet is moved from the fourth passageway 24 and past the point B.

FIG. 3 is a schematic illustration showing a duplex automatic sheet feeder according to a third embodiment of the invention. Referring to FIG. 3, the duplex automatic sheet feeder 1 of this embodiment includes a sheet input tray 10, a first passageway 21 (from points A to B), a sheet feeding mechanism 30, a second passageway 22 (from points B to C), a third passageway 23 (from points C to 23A), a fourth passageway 24 (from points C to B), a fifth passageway 25, a duplex sheet output tray 40, a guiding mechanism 50, a sheet detector 60 and a transporting mechanism 70.

The sheet input tray 10 stores a plurality of sheets S. In this embodiment, the uppermost sheet is first fed. The first passageway 21 is connected to the sheet input tray 10. The sheet feeding mechanism 30 feeds the sheets S one by one to the first passageway 21. In this embodiment, the sheet feeding mechanism 30 includes a pickup roller 31 and a separation roller set 32.

The second passageway 22 is connected to the first passageway 21 and has an image processing region 22A. In this embodiment, the image processing region 22A is a scanning region, and a sheet (document or original) moving across this region is scanned by an optical module 90. In another embodiment, the image processing region 22A is a printing region, and a printing module prints data on a sheet moving across this region.

The third passageway 23 is connected to the second passageway 22 so that the sheet can enter the third passageway 23 from the second passageway 22. The fourth passageway 24 is connected to the third passageway 23 and the second passageway 22, and the sheet coming from the third passageway 23 can enter the fourth passageway 24 but cannot enter the second passageway 22. The fifth passageway 25 is connected to the third passageway 23 so that the sheet coming from the third passageway 23 can enter the fifth passageway 25.

The duplex sheet output tray 40 is connected to the fifth passageway 25 and stores the sheets after being scanned in a duplex manner. The guiding mechanism 50 is located at a connection portion 26 between the third passageway 23 and the fifth passageway 25 to selectively guide the sheet S from the third passageway 23 to the fifth passageway 25. The sheet detector 60 located at the third passageway 23 is for detecting the sheet S moving through the third passageway 23. The sheet detector 60 may be a reflective or transmissive detector and outputs an infrared light ray, for example, to detect whether a leading edge or a trailing edge of the sheet has passed through a specific position to serve as a reference for feeding another sheet.

The transporting mechanism 70 includes a plurality of rollers 71 to 79. In a duplex scan mode, the transporting mechanism 70 transports the sheet S from the first passageway 21 to the duplex sheet output tray 40 sequentially through the second passageway 22, the third passageway 23, the fourth passageway 24, the second passageway 22, the third passageway 23 and the fifth passageway 25. When the sheet enters the third passageway from the second passageway, the state of the guiding mechanism 50 is shown by the upper dashed line profile. Thus, the guiding mechanism 50 may further guide the sheet S from the second passageway 22 to the third passageway 23. When the sheet enters the fourth passageway from the third passageway, the state of the guiding mechanism 50 is shown by the lower dashed line profile. Thus, the guiding mechanism 50 may guide the sheet S from the third passageway 23 to the fourth passageway 24. When the sheet enters the fifth passageway from the third passageway, the state of the guiding mechanism 50 is shown by the solid line profile. It is to be noted that the guiding mechanism 50 may only have two states as indicated by the upper dashed line profile and the solid line profile, and the structure of the passageway may be properly designed to make the sheet enter the fourth passageway from the third passageway smoothly.

In this embodiment, the third passageway 23 is also connected to the duplex sheet output tray 40. In a simplex scan mode, the transporting mechanism 70 may further transport the sheet S from the first passageway 21 to the duplex sheet output tray 40 sequentially through the second passageway 22 and the third passageway 23. An outlet 23A of the third passageway 23 is farther from the duplex sheet output tray 40 than an outlet 25A of the fifth passageway 25.

FIG. 4 is a schematic illustration showing a duplex automatic sheet feeder according to a fourth embodiment of the invention. Referring to FIG. 4, the duplex automatic sheet feeder of this embodiment further includes a simplex sheet output tray 80, which is connected to the third passageway 23, for transporting the sheet S from the first passageway 21 to the simplex sheet output tray 80 sequentially through the second passageway 22 and the third passageway 23 in a simplex mode. In this embodiment, the simplex sheet output tray 80 is located at a level higher than the duplex sheet output tray 40. Consequently, the user may identify whether the documents or sheets have been processed in a desired simplex or duplex manner according to the tray in which the documents or sheets are placed.

In the duplex automatic sheet feeder of the invention, the guiding mechanism is provided to guide the moving direction of the sheet, so the thin sheet is free from the conventional buckling phenomenon. In addition, two sheet output trays are provided so that the user can further identify whether the documents or sheets have been processed in a desired simplex or duplex manner. Thus, the feeder of the invention may be used in a quite convenient and human-oriented manner.

While the invention has been described by way of examples and in terms of preferred embodiments, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications.

Claims

1. A duplex automatic sheet feeder, comprising:

a sheet input tray for storing a plurality of sheets;

a first passageway connected to the sheet input tray;

a sheet feeding mechanism for feeding the sheets one by one to the first passageway;

a second passageway, which is connected to the first passageway and has an image processing region;

a third passageway connected to the second passageway;

a fourth passageway connected to the third passageway and the second passageway;

a fifth passageway connected to the third passageway;

a sheet output tray connected to the fifth passageway;

a guiding mechanism, located at a connection portion between the third passageway and the fifth passageway, for selectively guiding the sheet from the third passageway to the fifth passageway;

a sheet detector, located at the third passageway, for detecting the sheet moving through the third passageway; and

a transporting mechanism for transporting the sheet from the first passageway to the sheet output tray sequentially through the second passageway, the third passageway, the fourth passageway, the second passageway, the third passageway and the fifth passageway.

2. The feeder according to claim 1, wherein the third passageway is connected to the sheet output tray, and in a simplex mode, the transporting mechanism may further transport the sheet from the first passageway to the sheet output tray sequentially through the second passageway and the third passageway.

3. The feeder according to claim 2, wherein an outlet of the third passageway is farther from the sheet output tray than an outlet of the fifth passageway.

4. The feeder according to claim 1, further comprising a simplex sheet output tray, connected to the third passageway, for transporting the sheet from the first passageway to the simplex sheet output tray sequentially through the second passageway and the third passageway in a simplex mode.

5. The feeder according to claim 4, wherein the simplex sheet output tray is located at a level higher than the sheet output tray.

6. The feeder according to claim 1, wherein the guiding mechanism further guides the sheet from the third passageway to the fourth passageway.

7. The feeder according to claim 1, wherein the guiding mechanism further guides the sheet from the second passageway to the third passageway.

8. The feeder according to claim 1, further comprising:

an elastic guide for guiding the sheet from the third passageway to the fourth passageway.

9. The feeder according to claim 1, further comprising:

a sub-guiding mechanism, which may swing to guide the sheet from the third passageway to the fourth passageway or from the second passageway to the third passageway.