SHEET FEEDING DEVICE

Abstract

Imaging target media stacked in a tray are bent in a width direction orthogonal to a transmission direction so that rigidity of the imaging target media in the transmission direction increases than the rigidity before bending. Consequently, even though a separation imaging-target medium is bound together with a transportation imaging-target medium using a binding member, the separation imaging-target medium is transmitted to an imaging unit along with the transportation imaging-target medium by transporting rollers without bending in the transmission direction. A superimposed-transmission of the imaging target media is detected by sensors and rotation of the transmitting roller is stopped. Due to this, the superimposed-transmission of the imaging target media is stopped just before the imaging unit.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sheet feeding device that transports sheet-type imaging target media to imaging units that are set in an image scanner or an image copier.

2. Description of the Related Art

A sheet feeding device, in other words, a so-called auto document feeder (ADF) is suggested that transports originals (sheet-type imaging target media) one by one to imaging units that are set in an image scanner or an image copier.

In such a sheet feeding device, among the originals stacked in a tray, transportation originals that touch a transmitting roller are sequentially transmitted to the imaging units due to rotation of the transmitting roller. When a separation original is stacked on the transportation originals, a separation unit of a separating roller etc. touches the separation original and separates the separation original from the transportation originals by moving the separation original in a direction opposite to the transportation originals, which are transmitted in a transmission direction by the transmitting roller. Due to this, the originals are transported one by one to the imaging units.

When the transportation original and the separation original are bound together by a binding member such as a stapler at a front end of the transmission direction, and if the transportation original and the separation original are transmitted together to the imaging units due to a rotational force of the transmitting roller, a torque sensor detects current fluctuations of a direct current (DC) motor, in other words, detects load torque fluctuations of the DC motor that rotatably drives the transmitting roller. Thus, a bulk-transmission or superposed-transmission of the originals is detected and rotation-driving of the transmitting roller is stopped. Due to this, transportation of the originals by the transmitting roller is discontinued.

However, when the transportation original and the separation original are bound together by the binding member such as a stapler at a rear end of the transmission direction, the transportation original is transported to the imaging units by the transmitting roller, while the separation original is separated from the transportation original by the separating unit of the separating roller etc. Due to this, the separation original undergoes bending, ultimately a binding component of the binding member between the transportation original and the separation original ruptures, and a jam of originals occurs.

To overcome such a problem, before the binding component between the transportation original and the separation original ruptures and the jam of originals occurs, it is necessary to stop the rotation-driving of the transmitting roller and discontinue the transportation of the originals.

In the sheet feeding device disclosed in Japanese Patent No. 3197029, when the transportation original and the separation original are bound together by the binding member such as a stapler at the rear end of the transmission direction, and when the separation original, which is separated by the separating roller from the transportation original that is transported to the imaging unit, undergoes bending, the rotation of the transmitting roller is stopped.

However, in the sheet feeding device disclosed above, a dedicated sensor that detects bending of the separation original needs to be set. Thus, an electrical configuration of the device becomes complicated and cost of the device increases.

SUMMARY OF THE INVENTION

It is an object of the present invention to at least partially solve the problems in the conventional technology.

An aspect of the present invention, a sheet feeding device includes a tray in which sheet-type imaging target media are stacked; a transmitting roller that rotates and transmits, upon touching a single imaging target medium that is to be transported among the stacked imaging target media, the touched transportation imaging-target medium to an imaging unit; a separating unit that touches, among the stacked imaging target media, a separation imaging-target medium that is not to be transported, separates the separation imaging-target medium by moving the separation imaging-target medium in a direction opposite to the transportation imaging-target medium that is transmitted to the imaging unit by the transmitting roller, and prevents transmission of the separation imaging-target medium to the imaging unit; a rotatably driving unit that rotatably drives the transmitting roller; a transporting roller that rotates and transports, upon touching the transportation imaging-target medium transmitted by the transmitting roller, the touched transportation imaging-target medium to an imaging position of the imaging target medium formed by the imaging unit; a detecting sensor that is set between the transmitting roller and the transporting roller and that detects whether the imaging target media transmitted by the transmitting roller are only the transportation imaging-target media; and a controlling unit that stops, upon determining that the detected imaging target media include the imaging target media other than the transportation imaging-target media, rotation of at least the transmitting roller via the rotatably driving unit, wherein the tray includes a bending unit that bends the stacked imaging target media from a rear to a front end of a transmission direction, in a direction that intersects the transmission direction of the imaging target media by the transmitting roller and reduces a degree of bending of the imaging target media from the rear end to the front end of the transmission direction.

The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an outline of a sheet feeding device according to a first embodiment of the present invention;

FIG. 2 is a perspective view of a bending unit of a tray of the sheet feeding device;

FIG. 3 is a perspective view of a relation between the bending unit and an imaging target medium placed in the bending unit;

FIG. 4 is a perspective view of a relation between the bending unit and a plurality of imaging target media stacked in the bending unit;

FIGS. 5A and 5B are perspective views of an outline of detecting sensors;

FIG. 6 is a flowchart of operations of an image scanner to which the sheet feeding device according to the first embodiment is applied;

FIGS. 7A and 7B are perspective views of a bending unit of a tray of a sheet feeding device according to a second embodiment of the present invention;

FIG. 8 is a perspective view of a bending unit of a tray of a sheet feeding device according to a third embodiment of the present invention;

FIG. 9 is a perspective view of a relation between a pressing member and a bending unit of a tray of a sheet feeding device according to a fourth embodiment of the present invention;

FIG. 10 is a side view of a modification example of the pressing member;

FIG. 11 is a perspective view of a status when a thick imaging target medium is placed in the tray;

FIG. 12 is a side view of a pressing member of a sheet feeding device according to a fifth embodiment of the present invention; and

FIG. 13 is a side view of a pressing member of a sheet feeding device according to a sixth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of the sheet feeding device according to the present invention are explained below with reference to the accompanying drawings. However, the present invention is not to be thus limited to the embodiments described further. Although the sheet feeding device according to the present invention is set to an image scanner, the sheet feeding device can be set, for example, to an image copier etc.

A sheet feeding device according to a first embodiment of the present invention is explained below. FIG. 1 is a typical sectional view of an outline of the sheet feeding device according to the first embodiment.

A sheet feeding device 10 includes a tray 12, a transmitting roller 14, a separating roller 16 as a separating unit, a motor 18 as a rotatably driving unit, a pair of transporting rollers 20, a pair of detecting sensors 22, and a control circuit 24 as a controlling unit.

Sheet-type imaging target media P are stacked in the tray 12. As shown in FIG. 2, the tray 12 includes a bending unit 26.

As shown in FIG. 3, apart from bending the imaging target medium P, which is stacked in the tray 12, from a rear end to a front end of a transmission direction of the imaging target medium P by the transmitting roller 14, in a direction that intersects the transmission direction, the bending unit 26 also reduces a degree of bending of the imaging target medium P from the rear end to the front end of the transmission direction. As shown in FIG. 2, in the first embodiment, the bending unit 26 includes a foundation member 26a facing the imaging target medium P stacked in the tray 12 and a pair of bending members 26b set on the foundation member 26a on both edges of a width direction, which is orthogonal to the transmission direction.

The foundation member 26a is in the form of a rectangular board.

Further, each bending member 26b is positioned on the foundation member 26a and a bottom of each bending member 26b is integrated with the foundation member 26a. However, each bending member 26b can be detachably positioned on the foundation member 26a to enable insertion and separation of each bending member 26b to and from the foundation member 26a. Further, the bending members 26b are formed as triangular pillars and a length of the bending members 26b in the transmission direction is taken greater than a length of the bending members 26b in the width direction. A cross-sectional surface of each bending member 26b along the width direction spreads out at the bottom with respect to a lateral face of the bending unit 26. One side of the bending member 26b on an edge of the width direction is perpendicular to the foundation member 26a, forming a right-angled triangle along the transmission direction. Further, the cross-sectional surface along the width direction is similar to the right-angled triangle along the transmission direction and a surface area of the cross-sectional surface along the width direction is reduced. In other words, the bending members 26b project from both edges of the bending unit 26 in a stacking direction of the imaging target media P and an amount of projection goes on decreasing along the transmission direction.

Moreover, each bending member 26b according to the first embodiment includes a guiding unit 27. The guiding units 27 regulate a movement of the imaging target media P, which are transmitted by the transmitting roller 14, in the width direction. Each guiding unit 27 is integrated with the bending member 26b on both sides of the width direction. The guiding units 27 are in the form of rectangular boards and that are set on the bending members 26b with a board thickness in the width direction. A tip of each guiding unit 27 along the stacking direction of the imaging target media P occupies the same position as that of a tip of each bending member 26b at the rear end of the transmission direction. Due to this, in a portion of the tray 12 in which the imaging target media P are stacked, from the rear end to the front of the transmission direction, an area of the bending members 26b facing the imaging target media P goes on reducing with an increase in an area of the guiding units 27 facing the imaging target media P. Accordingly, the mutually opposing guiding units 27 regulate the movement of the imaging target media P, which are transmitted by the transmitting roller, in the width direction.

The transmitting roller 14 transmits the imaging target media P stacked in the tray 12 to imaging units 28. As shown in FIG. 4, the transmitting roller 14 touches a transportation imaging-target medium Pc among the imaging target media P stacked in the tray 12. The motor 18 rotates the transmitting roller 14 and the transmitting roller 14 transmits the touched transportation imaging-target medium Pc to the imaging units 28.

Among the imaging target media P stacked in the tray 12, the separating roller 16 prevents transmission of the separation imaging-target medium Ps that is not to be transported to the imaging units 28. The separating roller 16 touches the separation imaging-target medium PS, which is not to be transported, among the imaging target media P stacked in the tray 12. Further, the separating roller 16 separates the touched separation imaging-target medium Ps from the transportation imaging-target medium Pc by moving the separation imaging-target medium Ps in a direction opposite to the transportation imaging-target medium Pc, which is transported to the imaging units 28 by the transmitting roller 14, thus preventing transmission of the separation imaging-target medium Ps to the imaging units 28. To explain further, the transmitting roller 14 is positioned opposite to the separating roller 16. A torque limiter (not shown) is attached to a rotating shaft of the separating roller 16. When the imaging target media P are transmitted by the transmitting roller 14 to the imaging units 28, the separating roller 16 rotates with a slow rotational velocity than the rotational velocity of the transmitting roller 14. Consequently, the separating roller 16 moves the separation imaging-target medium Ps in the direction opposite to the transportation imaging-target medium Pc and prevents transmission of the separation imaging-target medium Ps to the imaging units 28.

The motor 18 rotatably drives the transmitting roller 14. The motor 18, which is coupled to the rotational shaft of the transmitting roller 14, receives a power supply from the control circuit 24 and rotates the transmitting roller 14.

The transporting rollers 20 transport the transportation imaging-target medium Pc to an imaging position of the imaging target medium P formed by the imaging units 28. The transporting rollers 20 are coupled to a motor 29 connected to the control circuit 24. The transporting rollers 20 rotate due to a driving force of the motor 29 to which power is supplied from the control circuit 24, touch the transportation imaging-target medium Pc transmitted by the transmitting roller 14, and transport the touched transportation imaging-target medium Pc to the imaging position of the imaging target medium P formed by the imaging units 28.

The detecting sensors 22 detect whether the imaging target media P transmitted by the transmitting roller 14 are only the transportation imaging-target media Pc. The detecting sensors 22 are set between the transmitting roller 14 and the transporting rollers 20. As shown in FIGS. 5A and 5B, the detecting sensors 22 are, for example, ultrasonic sensors. In the first embodiment, a pair of the detecting sensors 22 is arranged sandwiching a transportation path, which is a movement locus of the imaging target medium P, and the detecting sensors 22 are placed opposite to each other along a thickness direction of the imaging target medium P transmitted by the transmitting roller 14. Further, in the first embodiment, the detecting sensors 22 throw ultrasonic waves on the imaging target medium P and detect an amount of variation of the ultrasonic waves that undergo variation when passing through the imaging target medium P.

The control circuit 24 controls rotation of the transmitting roller 14 via the motor 18. The control circuit 24 is connected to the motor 18. When the detecting sensors 22 detect that the imaging target media P are not only the transportation imaging-target media Pc, the control circuit 24 stops the power supply to the motor 18 and stops rotation of the transmitting roller 14 via the motor 18. In the first embodiment, a threshold value of an output level of the detecting sensors 22 is set between the output level of the detecting sensors 22 when the detecting sensors 22 detect only one imaging target medium P and the output level of the detecting sensors 22 when the detecting sensors 22 detect more than two imaging target media P. When the output level of the detecting sensors 22 is less than the threshold value, the control circuit 24 determines that the imaging target media P detected by the detecting sensors 22 are not only the transportation imaging-target media Pc. In other words, when the output level of the detecting sensors 22 is less than the threshold value, the control circuit 24 determines that the imaging target media P detected by the detecting sensors 22 are more than two. Further, when it is determined that the imaging target media P detected by the detecting sensors 22 are more than two, the control circuit 24 stops the power supply to the motor 18 and stops rotation of the transmitting roller 14.

When a command to start scanning of the imaging target media P is input by a scan switch (not shown), the control circuit 24 supplies power to each of the motor 18 and the motor 29, and rotates the transmitting roller 14 and the transporting rollers 20, respectively. Further, when a command to end scanning of the imaging target media P is input by a scan stop switch (not shown), the control circuit 24 stops the power supply to at least the motor 18 and stops rotation of at least the transmitting roller 14. In the first embodiment, when the command to end scanning of the imaging target media P is input, the control circuit 24 stops the power supply to the motor 18 and the motor 29, and stops rotation of the transmitting roller 14 driven by the motor 18 and also stops rotation of the transporting rollers 20 driven by the motor 29.

As shown in FIG. 1, a pair of discharging rollers 30 is arranged downstream in the transmission direction of the imaging target media P ahead of the imaging units 28 and the discharging rollers 30 are arranged opposite to each other sandwiching the transportation path, which is the movement locus of the imaging target medium P.

Sheets, overhead projector (OHP) sheets etc. can be used as the imaging target media P mentioned above.

Operations of the sheet feeding device 10 according to the first embodiment of the present invention are explained below.

FIG. 6 is a flowchart of the operations of the sheet feeding device 10.

When the imaging target media P are stacked in the tray 12 of the sheet feeding device 10 and if the scan switch (not shown) of the image scanner is pressed, the command to start scanning of the imaging target media P is input to the control circuit 24, and power is supplied to the motor 18 and the motor 29 from the control circuit 24 (Yes at Step S100). Due to this, the transmitting roller 14 and the transporting rollers 20 are rotated (Step S102). Thus, the image scanner to which the sheet feeding device 10 is applied starts a process of scanning the imaging target media P. Next, the bending unit 26 of the tray 12 bends the imaging target media P stacked in the tray 12 in the direction that intersects the transmission direction of the imaging target media P by the transmitting roller 14, that is, the bending unit 26 bends the imaging target media P in the width direction that is orthogonal to the transmission direction.

Among the imaging target media P stacked in the tray 12, when a single transportation imaging-target medium Pc is not bound to the separation imaging-target medium Ps by using the binding member such as a stapler, the transportation imaging-target medium Pc touches the transmitting roller 14 that receives a rotational driving force of the motor 18 and the transportation imaging-target medium Pc is transported to the imaging units 28 due to the rotational force of the transmitting roller 14. On the other hand, when the separation imaging-target medium Ps touches the separating roller 16, a frictional force is generated between the separation imaging-target medium Ps and the separating roller 16. Due to this, the separation imaging-target medium Ps is separated from the transportation imaging-target medium Pc by moving the separation imaging-target medium Ps in the direction opposite to the transportation imaging-target medium Pc, which is transported to the imaging units 28 by the transmitting roller 14, and transmission of the separation imaging-target medium Ps to the imaging units 28 is prevented. Consequently, only the transportation imaging-target medium Pc, which is to be transmitted, is transmitted by the transmitting roller 14.

Alternatively, when the separation imaging-target medium Ps is not separated by the separating roller 16 from the transportation imaging-target medium Pc transmitted to the imaging units 28 by the transmitting roller 14, or when the separation imaging-target medium Ps and the transportation imaging-target medium Pc, which is transmitted to the imaging units 28 by the transmitting roller 14, are bound together at the front end of the transmission direction by using the binding member such as a stapler, the transportation imaging-target medium Pc and the separation imaging-target medium Ps are transmitted together to the imaging units 28 due to the rotational force of the transmitting roller 14, which receives the rotational driving force of the motor 18. For example, even if the separation imaging-target medium Ps and the transportation imaging-target medium Pc, which is transmitted to the imaging units 28 by the transmitting roller 14, are bound together at the rear end of the transmission direction by using the binding member such as a stapler, the separation imaging-target medium Ps is bent together with the transportation imaging-target medium Pc by the bending unit 26 along the width direction to strengthen rigidity in the transmission direction as described above. More specifically, because the rigidity in the transmission direction is increased than the rigidity before bending, the separation imaging-target medium Ps, when touches the separating roller 16, does not bend in the transmission direction. Consequently, the separation imaging-target medium Ps bound together with the transportation imaging-target medium Pc, which is transmitted to the imaging units 28 by the transmitting roller 14, at the rear end of the transmission direction by using the binding member such as a stapler is transmitted to the imaging units 28 along with the transportation imaging-target medium Pc due to the rotational force of the transmitting roller 14. In other words, when a plurality of imaging target media P, which are bound together at the rear end of the transmission direction by using the binding member, are transmitted by the transmitting roller 14 that receives the rotational driving force of the motor 18, a plurality of imaging target media P are transported together to the imaging units 28.

Subsequently, the imaging target medium P, which is transmitted by the transmitting roller 14 to the imaging position formed by the imaging units 28, is detected by the detecting sensors 22 (Step S104). Specifically, the ultrasonic waves are thrown on the imaging target medium P and the amount of variation of the ultrasonic waves that undergo variation when passing through the imaging target medium P is detected by the detecting sensors 22.

When the output level of the detecting sensors 22 is greater than the threshold value, the control circuit 24 determines that only the transportation imaging-target medium Pc is positioned at a detection position of the imaging target medium P in the detecting sensors 22. When the control circuit 24 determines that only the transportation imaging-target medium Pc is positioned at the detection position of the imaging target medium P in the detecting sensors 22, in other words, when the imaging target medium P detected by the detecting sensors 22 is only the transportation imaging-target medium Pc, the transportation imaging-target medium Pc is transported by the transporting rollers 20 to the imaging position formed by the imaging units 28 (Yes at Step S104), images of the transportation imaging-target medium Pc are taken by the imaging units 28 (Step S106), and image data corresponding to the transportation imaging-target medium Pc is generated using an image-data generating circuit (not shown) of the image scanner (Step S108). If the scan stop switch (not shown) of the image scanner is pressed, the command to end scanning of the imaging target media P is input to the control circuit 24 (Yes at Step S110) and the power supply to the motor 18 and the motor 29 from the control circuit 24 is stopped. Due to this, rotation of the transmitting roller 14 and the transporting rollers 20 is stopped, and the image scanner to which the sheet feeding device 10 is applied ends the process of scanning the imaging target media P (Step S112). If the command to end scanning of the imaging target media P is not input to the control circuit 24 (No at Step S110), while the control circuit 24 determines whether the imaging target medium P detected by the detecting sensors 22 is only the transportation imaging-target medium Pc, images of the transportation imaging-target medium Pc are taken by the imaging units 28 and the image data corresponding to the transportation imaging-target medium Pc is generated again.

On the other hand, when the output level of the detecting sensors 22 is less than the threshold value, the control circuit 24 determines that the imaging target media P detected by the detecting sensors 22 are not only the transportation imaging-target media Pc, in other words, the control circuit 24 detects a so-called bulk-transmission in which more than two imaging target media P are transmitted. When the control circuit 24 determines the bulk-transmission of the imaging target media P, in other words, when it is detected that a plurality of imaging target media P are transmitted to the transporting rollers 20, the power supply to the motor 18 and the motor 29 from the control circuit 24 is stopped (No at Step S104). Consequently, rotation of the transmitting roller 14 and the transporting rollers 20 is stopped. Due to this, transmission of the transportation imaging-target media Pc by the transmitting roller 14 and transportation of the transportation imaging-target media Pc by the transporting rollers 20 are stopped. Therefore, a plurality of imaging target media P are not transported by the transporting rollers 20 to the imaging position formed by the imaging units 28, however, transportation of the imaging target media P is stopped just before the transporting rollers 20 and the image scanner to which the sheet feeding device 10 is applied discontinues the process of scanning the imaging target media P (Step S114). Subsequently, by using an informing unit such as a display screen or a display lamp (not shown) that informs the user of an abnormal condition of the image scanner, it is informed to a user that the scanning process is discontinued.

As mentioned earlier, although a dedicated sensor that detects bending of the separation imaging-target medium Ps is not set, and even if a plurality of sheet-type imaging target media P are bound together at the rear end of the transmission direction by using the binding member, transportation of the imaging target media P, which are bound together, to the imaging position formed by the imaging units 28 can be suppressed. In other words, the bulk-transportation of a plurality of sheet-type imaging target media P to the imaging position formed by the imaging units 28 can be suppressed.

In the sheet feeding device 10 of the first embodiment, by using a simple structure of the bending unit 26 that includes the foundation member 26a and a pair of the bending members 26b, the rigidity of the imaging target media P, which are stacked in the tray 12, in the transmission direction can be increased.

In the bending unit 26, because the degree of bending of the imaging target media P, which are stacked in the tray 12, decreases from the rear end to the front end of the transmission direction, the imaging target media P can be smoothly transferred to the transmitting roller 14 and the separating roller 16.

When the imaging target media P, which are stacked in the tray 12, are transferred to the transmitting roller 14 and the separating roller 16, the movement of the imaging target media P in the width direction is regulated by the guiding units 27 of the bending unit 26. Accordingly, a displacement of the imaging target media P, which are bent by the bending unit 26, in the width direction can be prevented.

As mentioned earlier, a plurality of sheet-type imaging target media P, which are bound together at the rear end of the transmission direction, are transmitted directly from the tray due to the rotational force of the transmitting roller 14. Therefore, rupture of the imaging target media P due to the binding component of the imaging media P that are bound together by using the binding member, jam of the imaging target media P occurring between the transmitting roller 14 and the separating roller 16 can be suppressed.

In the first embodiment, when the imaging target media P detected by the detecting sensors 22 are not only the transportation imaging-target media Pc, the control circuit 24 stops the power supply to the motor 18 and the motor 29, and stops rotation of the transmitting roller 14 and the transporting rollers 20. However, the present invention is not to be thus limited. In the present invention, the sheet feeding device can be structured such that when the imaging target media P detected by the detecting sensors 22 are not only the transportation imaging-target media Pc, a rotatably driving unit stops rotation of at least the transmitting roller 14, for example, the control circuit 24 stops the power supply to the motor 18 and stops rotation of the transmitting roller 14.

In the first embodiment, although the separating roller 16 is applied as a separating unit, the present invention is not to be thus limited. In the present invention, for example, a separating board can be applied as a separating unit and can be arranged opposite to the transmitting roller 14. When the separating board touches the separation imaging-target medium Ps, a frictional force in a direction opposite to the transmission direction can be exerted on the separation imaging-target medium Ps and the separation imaging-target medium Ps can be separated from the transportation imaging-target medium Pc by moving the separation imaging-target medium Ps in the direction opposite to the transportation imaging-target medium Pc.

A sheet feeding device according to a second embodiment of the present invention is explained below. FIGS. 7A and 7B are perspective views of a bending unit of a tray of the sheet feeding device according to the second embodiment. Structural components that are similar to the first embodiment described above carry identical reference numerals and a redundant explanation thereof is omitted.

As shown in FIG. 7A, in the second embodiment, the tray 12 is rectangular in shape. The tray 12 is formed of the foundation member 26a arranged in a central portion of the width direction and a pair of the bending members 26b arranged on both edges of the width direction.

A surface of the foundation member 26a facing the imaging target medium P is an isosceles trapezoidal board having a wide base along the transmission direction. Alternatively, the surface of the foundation member 26a facing the imaging target medium P can be an isosceles triangular board having a wide base along the transmission direction.

A surface of each bending member 26b facing the imaging target medium P is a right-angled triangular board and a dimension of each bending member 26b in the width direction goes on decreasing along the transmission direction. Each bending member 26b is attached to the foundation member 26a using hinges. As shown in FIG. 7B, each bending member 26b is supported on both edges of the foundation member 26a in the width direction by the hinges such that each bending member 26b can be raised above the foundation member 26a. When raised above the foundation member 26a, each bending member 26b projects in a stacking direction of the imaging target media P and an amount of projection goes on decreasing along the transmission direction.

In the sheet feeding device 10 according to the second embodiment, a pair of the bending members 26b is supported by the hinges such that each bending member 26b can be raised above the foundation member 26a. Due to this, the user can select whether to bend the imaging target media P stacked in the tray 12. The remaining structural components in the second embodiment are the same as mentioned in the first embodiment.

A sheet feeding device according to a third embodiment of the present invention is explained below. FIG. 8 is a perspective view of a bending unit of a tray of the sheet feeding device according to the third embodiment. The structural components that are similar to the first and the second embodiments described above carry identical reference numerals and a redundant explanation thereof is omitted.

In the third embodiment, at least one of the two bending members 26b of the bending unit 26 described in the first embodiment is supported such that the bending member 26b can slide over the foundation member 26a along the width direction. More specifically, as shown in FIG. 8, both the bending members 26b are supported such that the bending members 26b can slide over the foundation member 26a along the width direction.

To explain further, each bending member 26b includes a rectangular board-shaped sliding unit in addition to the guiding unit 27 described in the first embodiment. Each sliding unit is thick in the stacking direction of the imaging target medium P and that is slidably mounted on rail members (not shown) that are fixed to the foundation member 26a along the width direction. Due to this, each sliding unit slides along the rail members in the width direction, thus enabling the bending members 26b to slide over the foundation member 26a along the width direction. In the third embodiment, both the bending members 26b assume a centerline in the width-direction of the foundation member 26a as a center and slide over the foundation member 26a along the width direction in conjunction with each other. If only one of the two bending members 26b is slidably supported on the foundation member 26a, one of the two bending members 26b can be fixed to the foundation member 26a, while the other can be supported such that the other bending member 26b can slide along the rail members fixed to the foundation member 26a along the width direction.

In the sheet feeding device 10 according to the third embodiment, at least one of the two bending members 26b, or both the bending members 26b are supported such that the bending members 26b can slide along the rail members over the foundation member 26a in the width direction. Due to this, spacing between the bending members 26b can be adjusted according to a size of the imaging target medium P in the width direction. Consequently, the imaging target medium P can be bent according to the size. The remaining structural components in the present embodiment are the same as that mentioned in the first embodiment.

A sheet feeding device according to a fourth embodiment of the present invention is explained below. FIG. 9 is a perspective view of a bending unit of a tray of the sheet feeding device according to the fourth embodiment. The sheet feeding device 10 according to the fourth embodiment includes, in addition to any one of the first to the third embodiments, a pressing member 34 that presses the imaging target media P stacked in the tray 12 towards the tray 12 and bends the imaging target media P. The structural components that are similar to the first, second, and third embodiments described above carry identical reference numerals and a redundant explanation thereof is omitted.

The sheet feeding device 10 according to the fourth embodiment includes the pressing member 34, which is placed opposite to the tray 12 and includes a pressing and bending unit 34a and a supporting unit 34b.

The pressing and bending unit 34a presses the imaging target media P stacked in the tray towards the tray 12 and bends the imaging target media P according to a shape of the bending unit 26. The pressing and bending unit 34a is spherical in shape. Alternatively, the pressing and bending unit 34a can be formed as a block as shown in FIG. 10.

The supporting unit 34b, which supports the pressing and bending unit 34a at the front end, is in the form of a long rod. In such a supporting unit 34b, a proximal portion of the supporting unit 34b on an opposite side of the pressing and bending unit 34a is fixed to a chassis of the image scanner to which the sheet feeding device 10 is applied.

As shown in FIG. 11, when a thick imaging target medium P is stacked in the tray 12, in other words, when the imaging target medium P having more rigidity than a thin imaging target medium P is stacked in the tray 12, bending of the imaging target medium P is suppressed. However, as shown in FIG. 9, in the sheet feeding device 10 according to the fourth embodiment, by pressing the imaging target medium P towards the tray 12 using the pressing and bending unit 34a of the pressing member 34, the imaging target medium P is bent according to the shape of the bending unit 26. Consequently, the rigidity of the imaging target medium P in the transportation direction can be further increased.

In the fourth embodiment, when the proximal portion of the supporting unit 34b on the opposite side of the pressing and bending unit 34a is fixed, the supporting unit 34b can be structured to bend almost in the stacking direction of the imaging target medium P.

A sheet feeding device according to a fifth embodiment of the present invention is explained below. FIG. 12 is a typical sectional view of an outline of the sheet feeding device according to the fifth embodiment. In the sheet feeding device 10 according to the fifth embodiment, the proximal portion of the supporting unit 34b on the opposite side of the pressing and bending unit 34a is assumed as a center and the pressing member 34 described in the fourth embodiment can oscillate about the center. Further, structural components that are similar to the fourth embodiment described above carry identical reference numerals and a redundant explanation thereof is omitted.

Depending on a reaction force due to a pressing force exerted by the pressing and bending unit 34a on the imaging target medium P, the pressing and bending unit 34a of the pressing member 34 according to the fifth embodiment can oscillate almost in the stacking direction of the imaging target medium P about the center, that is, the proximal portion of the supporting unit 34b. In the supporting unit 34b, to bias the pressing and bending unit 34a towards the tray 12, the proximal portion on the opposite side of the pressing and bending unit 34a can be biased using a biasing member such as a leaf spring.

In the sheet feeding device 10 according to the fifth embodiment, depending on the reaction force due to the pressing force exerted by the pressing and bending unit 34a on the imaging target medium P, the pressing member 34 oscillates about the center, that is, the proximal portion of the supporting unit 34b on the opposite side of the pressing and bending unit 34a. Due to this, a load exerted by the pressing and bending unit 34a on the imaging target medium P can be reduced as compared to the load exerted by the pressing member 34 in which the proximal portion of the supporting unit 34b on the opposite side of the pressing and bending unit 34a does not oscillate (the pressing member 34 according to the fourth embodiment described above).

A sheet feeding device according to a sixth embodiment of the present invention is explained below. FIG. 13 is a typical sectional view of an outline of the sheet feeding device according to the sixth embodiment. In the sheet feeding device 10 according to the sixth embodiment, the pressing and bending unit 34a of the pressing member 34 according to the fourth embodiment is in the form of a sliding roller, and the frictional force between the pressing and bending unit 34a and the imaging medium P is reduced. Further, structural components that are similar to the fourth embodiment described above carry identical reference numerals and a redundant explanation thereof is omitted.

In the sheet feeding device 10 according to the sixth embodiment, the pressing and bending unit 34a of the pressing member 34 is in the form of the sliding roller that is supported by the supporting unit 34b allowing free rotation of the pressing and bending unit 34a. The sliding roller according to the sixth embodiment slides by rotating with respect to the pressed imaging target medium P along with the movement of the pressed imaging target medium P in the transmission direction.

In the sheet feeding device 10 according to the sixth embodiment, when the imaging target medium P, which is pressed by the pressing and bending unit 34a of the pressing member 34, moves along the transmission direction, the pressing and bending unit 34a slides by rotating with respect to the imaging target medium P. Therefore, increase in the frictional force arising between the pressing and bending unit 34a and the imaging target medium P can be suppressed without reducing the pressing force exerted on the imaging target medium P by the pressing and bending unit 34a of the pressing member 34.

According to an embodiment of the present invention, imaging target media stacked in a tray are bent by using a bending unit of the tray in a direction that crosses a transmission direction of the imaging target media by a transmitting roller, for example, in a width direction that is orthogonal to the transmission direction. Rigidity of the imaging target media, which are stacked in the tray, along the transmission direction is increased than the rigidity of the imaging target media before bending. Consequently, when a transportation imaging-target medium and a separation imaging-target medium are bound together using a binding member such as a stapler, and when the transportation imaging-target medium is transmitted to imaging units by the transmitting roller, the separation imaging-target medium is transmitted to the imaging units along with the transportation imaging-target medium without bending in the transmission direction. In other words, when a plurality of imaging target media bound together by the binding member are transmitted by the transmitting roller, a plurality of imaging target media are transmitted together to the imaging units. Further, detecting sensors detect that the imaging target media transmitted to transporting rollers are not only the transportation imaging-target media, in other words, the detecting sensors detect that a plurality of imaging target media are transmitted to the transporting roller, and a controlling unit stops rotation of at least the transmitting roller. Consequently, a plurality of imaging target media are not transported by the transporting rollers to an imaging position formed by the imaging units and transportation is stopped just before the transporting roller. Thus, even though a dedicated sensor that detects bending of the separation imaging-target media is not set, when a plurality of imaging target media are bound together by the binding member, transportation of a plurality of imaging target media, which are bound together, to the imaging position formed by the imaging units can be suppressed.

According to an embodiment of the present invention, a degree of bending of the imaging target media stacked in the tray reduces from a rear end to a front end of the transmission direction. Therefore, the imaging target media can be smoothly transferred to the transmitting roller and a separating unit.

According to an embodiment of the present invention, the bending unit includes a foundation member and a pair of bending members. Due to such a simple structure of the bending unit, the rigidity of the imaging target media, which are stacked in the tray, in the transmission direction can be increased.

According to an embodiment of the present invention, a pair of the bending members is supported such that the bending members can be raised above the foundation member. Therefore, a user can select whether to bend the imaging target media.

According to an embodiment of the present invention, at least one of the two bending members is supported such that the bending member can slide over the foundation member along the width direction. Therefore, spacing between the two bending members can be adjusted according to a size of the imaging target media in the width direction. Due to this, the imaging target media can be bent according to the size.

According to an embodiment of the present invention, when the imaging target media stacked in the tray are transferred to the transmitting roller and the separating unit, the movement of the imaging target medium along the width direction is regulated using guiding units. Consequently, a displacement of the imaging target media, which are bent by the bending unit, in the width direction can be prevented.

According to an embodiment of the present invention, when thick imaging target media are stacked in the tray, in other words, when the imaging target media having more rigidity than thin imaging target media are stacked in the tray, bending of the imaging target media is suppressed. However, because the imaging target media are bent towards the tray by the pressing and bending unit of the bending member, the imaging target media are bent according to a shape of the bending unit. Consequently, the rigidity of the imaging target media in the transmission direction can be further increased.

According to an embodiment of the present invention, depending on a reaction force due to a pressing force exerted by the pressing and bending unit on the imaging target media, the pressing member oscillates considering a proximal portion of the supporting unit as a center. Due to this, load added to the imaging target media by the pressing and bending unit can be reduced as compared to the bending member in which the proximal portion of the supporting member does not oscillate.

According to an embodiment of the present invention, when the imaging target media, which are pressed by the pressing and bending unit of the bending member, move along the transmission direction, the pressing and bending unit slides with respect to the imaging target media. Therefore, increase in a frictional force arising between the pressing and bending unit and the imaging target medium can be suppressed without reducing the pressing force on the imaging target media exerted by the pressing and bending unit.

Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.

Claims

1. A sheet feeding device comprising:

a tray in which sheet-type imaging target media are stacked;

a transmitting roller that rotates and transmits, upon touching a single imaging target medium that is to be transported among the stacked imaging target media, the touched transportation imaging-target medium to an imaging unit;

a separating unit that touches, among the stacked imaging target media, a separation imaging-target medium that is not to be transported, separates the separation imaging-target medium by moving the separation imaging-target medium in a direction opposite to the transportation imaging-target medium that is transmitted to the imaging unit by the transmitting roller, and prevents transmission of the separation imaging-target medium to the imaging unit;

a rotatably driving unit that rotatably drives the transmitting roller;

a transporting roller that rotates and transports, upon touching the transportation imaging-target medium transmitted by the transmitting roller, the touched transportation imaging-target medium to an imaging position of the imaging target medium formed by the imaging unit;

a detecting sensor that is set between the transmitting roller and the transporting roller and that detects whether the imaging target media transmitted by the transmitting roller are only the transportation imaging-target media; and

a controlling unit that stops, upon determining that the detected imaging target media include the imaging target media other than the transportation imaging-target media, rotation of at least the transmitting roller via the rotatably driving unit,

wherein the tray includes a bending unit that bends the stacked imaging target media from a rear to a front end of a transmission direction, in a direction that intersects the transmission direction of the imaging target media by the transmitting roller and reduces a degree of bending of the imaging target media from the rear end to the front end of the transmission direction.

2. The sheet feeding device according to claim 1, wherein

the bending unit includes a foundation member facing the stacked imaging target media and a pair of bending members mounted on the foundation member on both edges of a width direction that is orthogonal to the transmission direction, and

the bending members project in a stacking direction of the imaging target media and an amount of projection reduces along the transmission direction.

3. The sheet feeding device according to claim 2, wherein

the bending members are supported on both edges of the width direction of the foundation member such that the bending members can be raised above the foundation member, and

the bending members project, upon raising, from lateral surfaces of the foundation member in a stacking direction of the imaging target media and the amount of projection reduces along the transmission direction.

4. The sheet feeding device according to claim 2, wherein at least one of the two bending members is supported such that the bending member can slide over the foundation member along the width direction.

5. The sheet feeding device according to claim 2, wherein the bending members include mutually opposing guiding units that regulate a movement of the imaging target media transmitted by the transmitting roller, in the width direction.

6. The sheet feeding device according to claim 1, further comprising:

a pressing member arranged facing the tray and that includes a bending and pressing member that presses the imaging target media stacked in the tray towards the tray and bends the imaging target media according to a shape of the bending unit, and a supporting unit that supports the bending and pressing unit at the front end.

7. The sheet feeding device according to claim 6, wherein, depending on a reaction force due to a pressing force exerted by the pressing and bending unit on the imaging target media, the pressing and bending unit of the pressing member can oscillate in a direction away from the tray with a proximal portion of the supporting unit as a center.

8. The sheet feeding device according to claim 6, wherein the pressing and bending unit includes a sliding roller supported by the supporting unit allowing free rotation, and the pressing and bending unit slides with respect to the pressed imaging target media along with a movement of the pressed imaging target media in the transmission direction.