Patent Grant
8205876
This application claims priority under 35 U.S.C. §119 from Japanese Patent Application No. 2009-129362 filed on May 28, 2009. The entire subject matter of the application is incorporated herein by reference.
1. Technical Field
The following description relates to one or more techniques for a sheet ejector to eject sheets onto a catch tray.
2. Related Art
In general, as an example of a sheet ejector configured to eject a sheet (e.g., a document sheet and a sheet with an image formed thereon) onto a catch tray, a sheet ejector has been known that ejects a sheet in an insertion mode so as to insert the sheet under a stack of sheets that have already been ejected on a catch tray.
In the meantime, the aforementioned sheet ejector has a problem that as the number of the sheets stacked on the catch tray increases, it might be harder to insert a later-ejected sheet under a stack of earlier-ejected sheets on the catch tray due to an increased frictional resistance between the later-ejected sheet and a bottom one of the earlier-ejected sheets. It might lead to a wrinkled sheet or a paper jam.
In particular, when heavy sheets or sheets with a high degree of surface roughness are ejected, the frictional resistance between the sheets tends to rise. Consequently, it might be harder in an earlier stage to insert a later-ejected sheet under a stack of earlier-ejected sheets on the catch tray. Thus, it might be more likely to lead to a wrinkled sheet and a reduced number of sheets permitted to be ejected onto the catch tray.
The above problems are unique to a sheet ejector configured to eject sheets in the insertion mode, but do not matter to a sheet ejector configured to eject sheets in a stacking mode to sequentially stack a later-ejected sheet onto earlier-ejected sheets on a catch tray.
Aspects of the present invention are advantageous to provide one or more improved techniques that make it possible to eject sheets in the insertion mode in a preferable manner depending on situations.
According to aspects of the present invention, a sheet ejector is provided that is configured to eject sheets so as to insert a later-ejected sheet under an earlier-ejected sheet on a catch tray. The sheet ejector includes a feed roller provided to the catch tray, wherein the feed roller is configured to feed, in a predetermined ejecting direction, the later-ejected sheet that is inserted under the earlier-ejected sheet, and a switching mechanism configured to switch a state of the feed roller relative to a sheet on the catch tray between a contact state where the feed roller contacts the sheet on the catch tray and a non-contact state where the feed roller is kept from contacting the sheet on the catch tray.
According to aspects of the present invention, further provided is a sheet feeder, which includes a sheet ejector configured to eject sheets so as to insert a later-ejected sheet under an earlier-ejected sheet on a catch tray. The sheet ejector includes a feed roller provided to the catch tray, wherein the feed roller is configured to feed, in a predetermined ejecting direction, the later-ejected sheet that is inserted under the earlier-ejected sheet, and a switching mechanism configured to switch a state of the feed roller relative to a sheet on the catch tray between a contact state where the feed roller contacts the sheet on the catch tray; and a non-contact state where the feed roller is kept from contacting the sheet on the catch tray.
It is noted that various connections are set forth between elements in the following description. It is noted that these connections in general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect.
Hereinafter, an embodiment according to aspects of the present invention will be described with reference to the accompany drawings. In the following description, an explanation about a general configuration of a document feeder 1 having a sheet ejector in the embodiment will first be provided and followed by an explanation about a detailed configuration of the sheet ejector.
Further, in the following description, a “feeding direction” represents a direction (see a thick solid line in
<General Configuration of Document Feeder>
As shown in
As illustrated in
The flatbed scanner 2 includes a platen glass 2G on which a document sheet is statically placed when the document feeder 1 is opened, and an image sensor 2S. The flatbed scanner 2 is configured to read an image on a document sheet that is statically placed on the platen glass 2G while scanning the document sheet with the image sensor 2S, and to read an image on a document sheet that is conveyed in a reading position R by the document feeder 1.
The document feeding unit 30 is formed with a substantially U-shaped feeding path 31 (see a thick solid line in
On the feeding path 31, a pickup roller 41, a pickup arm 42, a separation roller 43, a separation arm 44, first feed rollers 45, second feed rollers 47, and ejection rollers 200 are disposed sequentially from an upstream side to a downstream side. Between the first feed rollers 45 and the second feed rollers 47, there is a reading position R that faces the image sensor 2S across the platen glass 2G. The reverse path 32 diverges from the feeding path 31 downstream relative to the second feed rollers 47. In a diverging point between the feeding path 31 and the reverse path, there is a flap-shaped first guide member 61 configured to swing up and down so as to sort a document sheet into one of the feeding path 31 and the reverse path 32.
The reverse path 32 includes a first path 32A that extends from the diverging point toward the outside (rightward in
The switchback rollers 53 are known rollers for reversing (switching back) a document sheet upside down, each of which is rotated in any of a forward direction for ejecting the document sheet out of the reverse path 32 and a backward direction for pulling back the document sheet. Specifically, under a known control technique, the switchback rollers 53 is rotated in the forward direction so as to partially eject the document sheet outward until a tail end of the document sheet completely passes through a diverging point between the first path 32A and the second path 32B. Then, after a temporary stop, the switchback rollers 53 are rotated in the backward direction so as to pull back and feed the document sheet to the second path 32B.
Switching between the first path 32A and the second path 32B is carried out by a flap-shaped second guide member 62, which is disposed in the diverging point between the first path 32A and the second path 32B and configured to swing up and down.
<Detailed Configuration of Sheet Ejector>
A sheet ejector of the embodiment includes the catch tray 100, the ejection rollers 200 configured to eject a document sheet fed on the feeding path 31 onto the catch tray 100, an assist feed roller 300, and a switching mechanism (as will be described below, which includes a flap 120, a cam 410, and roller guards 430). As will be explained in detail below, the sheet ejector is configured to eject a document sheet so as to insert the document sheet under a stack of document sheets that have already been ejected on the catch tray 100.
[Configuration of Catch Tray]
The catch tray 100 is disposed above the feed tray 10 and provided with a fixed tray 110 and a flap 120 placed upstream relative to the fixed tray 110. The fixed tray 110 is fixed to a main body frame 1A constituting an outer frame so as not to be displaced relative to the document feeding unit 30.
The flap 120 is supported by the main body frame 1A such that an upstream end 122 thereof is swingable around a swing shaft 121 (a swing center) provided at a downstream side. An upstream side of the flap 120 is bent downward, and the bending portion of the flap 120 is formed with a protruding section 123 that protrudes upward.
The flap 120 is swung up and down by a cam 410 provided to the main body frame 1A. The cam 410 is disposed at an upstream side of the flap 120. The cam 410 has a push-up bar 411 that is provided at a lower side of the cam 410 and configured to extend in the width direction, a pair of shaft portions 412 supported by the main body frame 1A rotatably in forward and backward directions, and a pair of joints 413 that connect both ends of the push-up bar 411 and the shaft portions 412, respectively.
When the shaft portions 412 are rotated, the cam 410 causes the flap 120 to swing between a lower position shown in
As illustrated in
[Configuration of Assist Feed Roller]
As illustrated in
The assist feed roller 300 feeds a later-ejected document sheet, which is inserted under earlier-ejected document sheets, in the ejecting direction when driven to rotate clockwise in
The assist feed roller 300 has a roller surface configured to apply, to document sheets that have already been ejected on the catch tray 100, such a frictional resistance as not to feed (move) the already-ejected document sheets only by the rotation of the assist feed roller 300. Thereby, it is possible to prevent the document sheets that have already been ejected on the catch tray 100 from falling out of the catch tray 100.
Further, when driven, the assist feed roller 300 rotates at a circumferential velocity equal to or less than an ejection velocity (a circumferential velocity of the ejection rollers 200) at which the ejection rollers 200 ejects a document sheet. Thereby, since a feeding velocity at which the assist feed roller 300 feeds a document sheet is equal to or less than the ejection velocity at which the ejection rollers 200 ejects a document sheet, it is possible to prevent the earlier-ejected document sheets from falling out of the catch tray 100.
To provide a supplemental explanation, when a later-ejected document sheet is inserted under an earlier-ejected document sheet, the earlier-ejected document sheet is likely to move due to a friction between the earlier-ejected document sheet and the later-ejected document sheet. Therefore, if the feeding velocity of the assist feed roller 300 is higher than the ejection velocity of the ejection roller 200, the earlier-ejected document sheet might move and fall out of the catch tray 100. Thus, in the embodiment, as the feeding velocity of the assist feed roller 300 is equal to or lower than the ejection velocity of the ejection rollers 200, it is possible to prevent the earlier-ejected document sheet from falling out of the catch tray 100.
Subsequently, an explanation will be provided about a configuration of a driving mechanism for the assist feed roller 300. As illustrated in
The motor 310 is a known motor that is disposed in an appropriate position within the main body frame 1 and rotatable in both rotational directions. The motor 310 transmits a driving force to the pickup roller 41, the separation roller 43, the first feed rollers 45, the second feed rollers 47, the ejection rollers 200, the third feed rollers 51, the switchback rollers 53, and the assist feed rollers 300.
The gear unit 320 is disposed on a side of the assist feed roller 300 in the width direction (see
The switchback gear 321 is configured to rotate integrally with an upper roller of the switchback rollers 53 and transmit to the switchback rollers 53 the driving force which is provided by the motor 321 directly or indirectly via one or more other gears. The intermediate gear 322 is engaged with the switchback roller gear 321 and the sun gear 323 so as to transmit the driving force from the switchback roller gear 321 to the sun gear 323.
The sun gear 323 and the planet gear 324 are engaged with each other in a state where rotational shafts of the sun gear 323 and the planet gear 324 are inserted into holes provided to the joint 326, respectively. The sun gear 323 and the planet gear 324, joined with each other, are configured such that the planet gear 324 is swingable around the rotational shaft (a rotation center) of the sun gear 323 between a position where the planet gear 324 is engaged with the transmission gear 325 and a position where the planet gear 324 is away from the transmission gear 325.
The transmission gear 325 is configured to rotate integrally with the assist feed roller 300 and transmit to the assist feed roller 300 the driving force which is transmitted by the planet gear 324.
In the driving mechanism configured as above, as shown in
Meanwhile, as illustrated in
[Configuration of Switching Mechanism]
As shown in
As will be described in detail below, the switching mechanism is configured to switch a state of the assist feed roller 300 relative to a document sheet M on the catch tray 100 between a contact state where the assist feed roller 300 contacts the document sheet M (see
Each of the roller guards 430 is formed substantially in an arc shape when viewed in the width direction. The roller guards 430 are disposed at the upstream end of the fixed tray 110 so as to pinch the assist feed roller 300 (see
Specifically, each of the roller guards 430 is configured to swing between a protruding position and a receding position. In the protruding position, as illustrated in
Each of the roller guards 430 has a contact section 432 that is provided at an upstream end of each roller guard 430 and configured to contact a downstream end 124 of the flap 120. The contact section 432 is pushed by (the downstream end 124 of) the flap 120 and swung from the receding position to the protruding position, in response to the swing motion of the flap 120 from the upper position to the lower position. At this time, the contact section 432 is supported in contact with the downstream end 124 of the flap 120 and held in the protruding position.
In the state where each of the roller guards 430 is held in the protruding position, a distance L1 is longer than a distance L2 (see
Thereby, when the load of the document sheet M ejected on the catch tray 100 is applied to the load receiving section 433, each roller guard 430 is prevented from being pushed down to the receding position, based on the principle of leverage, since the distance is longer than the distance L2. Consequently, it is possible to avoid contact between the assist feed roller 300 and the document sheet M in the non-contact state.
Meanwhile, as shown in
<Operation of Document Feeder>
Next, an explanation will be provided about an operation of the document feeder 1 configured as above in each ejection mode.
[Operation in Stacking Mode]
As shown in
As shown in
When the document feeding is started, the document sheet M2 on the feed tray 10 is fed to the feeding path 31 by the separation roller 43. Then, the document sheet M2 is fed to the reading position R by the first feed roller 45 such that the first read side P3 is read by the image sensor 2S. Thereafter, the document sheet M2 is conveyed to the reverse path 32 (the first path 32A) by the second feed rollers 47 and the first guide member 61.
The document sheet M2 fed to the reverse path 32 (the first path 32A) is ejected toward the outside by the third feed rollers 51 and the switchback rollers 53 rotating in the forward direction. At this time, as illustrated in
According to the sheet ejector configured as above, even though the document sheet M1 that has already been ejected on the catch tray 100 is partially inserted between the roller guards 430 set in the protruding position and contacts the assist feed roller 300 as the document sheet M1 is folded or curled, it is possible to prevent the document sheet M1 from being fed and falling out of the catch tray 100.
When the document sheet M2 is almost completely fed ahead of the switchback rollers 53, the switchback rollers 53 are temporarily stopped by a known control technique. At this time, the first guide member 61 is swung to the lower position, and the second guide member 62 is swung to the upper position. Further, the document sheet M2 is set with the first read side P3 facing up and the second read side P4 facing down.
After that, as shown in
The document sheet M2, of which the second read side P4 has been read, is ejected onto the catch tray 100 by the ejection rollers 200. In the stacking mode, the protruding section 123 of the flap 120 is located lower than a nipping position of the ejection rollers 200. Therefore, the document sheet M2 is ejected so as to be stacked on the document sheet M1 that has already been ejected on the catch tray 100.
At this time, the roller guards 430 are in the protruding position, and therefore the state between the assist feed roller 300 and the document sheets M (M1 and M2) on the catch tray 100 is set in the non-contact state. Thereby, even though the assist feed roller 300 is driven to rotate (see
It is noted that the document sheet M2 is ejected onto the document sheet M1, with the first read side P3 facing down and the second read side P4 facing up. In the same manner, the document sheet M1 has been ejected with the first read side P1 facing down and the second read side P2 facing up. Hence, in the stacking mode, the document sheets M1 and M2 are stacked on the catch tray 100 with pages thereof arranged in the following order from the bottom, P1, P2, P3, and P4. The above order of the pages is the same as that for the document sheets M1 and M2 placed on the feed tray 10.
[Operation in Insertion Mode]
As shown in
As shown in
When the document feeding is started, the document sheet M2 on the feed tray 10 is fed to the feeding path 31 by the separation roller 43. Then, the document sheet M2 is fed to the reading position R by the first feed roller 45 such that the read side P2 is read by the image sensor 2S.
The document sheet M2, of which the read side P2 has been read, is ejected onto the catch tray 100 by the ejection rollers 200. In the insertion mode, the protruding section 123 of the flap 120 (a rear end of the document sheet M1) is located higher than the nipping position of the ejection rollers 200. Therefore, the document sheet M2 is ejected so as to be inserted under the document sheet M1 that has already been ejected on the catch tray 100.
At this time, the roller guards 430 are in the receding position, and therefore the state between the assist feed roller 300 and the document sheets M (M1 and M2) on the catch tray 100 is set in the contact state. Thereby, the ejected document sheet M2 is fed by the assist feed roller 300 in an auxiliary manner, and inserted under the earlier-ejected document sheet M1 in a preferable manner.
In the embodiment, the flap 120 is configured to extend in the horizontal direction. Additionally, the fixed tray 110 is configured to extend obliquely upward. Further, the assist feed roller 300 is disposed at the upstream end of the fixed tray 110. Therefore, a leading end of the ejected document sheet M2 moves toward the assist feed roller 300. Thereby, it is possible to certainly establish contact between the document sheet M2 and the assist feed roller 300 and thus to certainly obtain the operation of the assist feed roller 300.
Further, the document sheet M2 is ejected under the document sheet M1, with the read side P2 facing up. In the same manner, the document sheet M1 is ejected with the read side P1 facing up. Therefore, in the insertion mode, the document sheets M1 and M2 are stacked with pages thereof arranged in the following order from the top, P1 and P2. The above order of the pages is the same as that for the document sheets M1 and M2 placed on the feed tray 10.
As described above, according to the document feeder 1 having the sheet ejector of the embodiment, it is possible to assist the later-ejected document sheet M2 to insert under the earlier-ejected document sheet M1 in a preferable manner, by employing the assist feed roller 300. Further, it is possible to switch the state of the assist feed roller 300 relative to the sheet on the catch tray 100 between the contact state and the non-contact state, by employing the switching mechanism (the flap 120, the cam 410, and the roller guards 430). Thus, it is possible to insert the later-ejected document sheet M2 under the earlier-ejected document sheet M1 in a preferable manner, by making the assist feed roller 300 function depending on whether the ejection mode is set in the insertion mode.
In the embodiment, the switching mechanism includes the roller guards 430, which is configured to switch the state of the assist feed roller 300 relative to the sheet on the catch tray 100 between the contact state and the non-contact state, by swinging between the protruding position and the receding position. Therefore, it is possible to fix the position of the assist feed roller 300. Thereby, it is possible to make a configuration of a driving mechanism for the assist feed roller 300 simpler than that for a movable assist feed roller 300.
In particular, in the embodiment, the switching mechanism (the roller guards 430) is configured to operate in conjunction with the swing motion of the flap 120 and swing between the protruding position and the receding position, so as to switching the state between the assist feed roller 300 and a sheet on the catch tray 100 between the contact state and the non-contact state. Hence, it is not required to separately provide a mechanism for swinging the roller guards 430. Thereby, it is possible to simplify the configuration of the document feeder 1 and save a manufacturing cost of the document feeder 1.
In the embodiment, the document feeder 1 is configured to provide the driving force of the single motor 310 to the assist feed roller 300 and the switchback rollers 53, and to drive or stop the assist feed roller 300 depending on the rotational direction of the motor 310. Therefore, it is possible to make the assist feed roller 300 function as needed. Further, it is possible to reduce the manufacturing cost and the size of the document feeder 1, since it is not required to separately provide a motor for driving the assist feed roller 300.
Hereinabove, the embodiment according to aspects of the present invention has been described. The present invention can be practiced by employing conventional materials, methodology and equipment. Accordingly, the details of such materials, equipment and methodology are not set forth herein in detail. In the previous descriptions, numerous specific details are set forth, such as specific materials, structures, chemicals, processes, etc., in order to provide a thorough understanding of the present invention. However, it should be recognized that the present invention can be practiced without reapportioning to the details specifically set forth. In other instances, well known processing structures have not been described in detail, in order not to unnecessarily obscure the present invention.
Only an exemplary embodiment of the present invention and but a few examples of their versatility are shown and described in the present disclosure. It is to be understood that the present invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein. For example, the following modifications are possible.
In the aforementioned embodiment, the catch tray 100 includes the single assist feed roller 300 (see
In the aforementioned embodiment, each roller guard 430 is configured to swing between the protruding position and the receding position. However, for instance, each roller guard 430 may be configured to move linearly up and down between a protruding position and a receding position.
In the aforementioned embodiment, each roller guard 430 is configured to, in response to the flap 120 swinging down, be pushed by the flap 120 and swung from the receding position to the protruding position. Further, each roller guard 430 is configured to, in response to the flap 120 swinging up, swing from the protruding position to the receding position owing to the weight of the downstream side of each roll guard 430 relative to the swing shaft 431 that is heavier than the upstream side.
However, for instance, a spring may be provided that is configured to always urge each roller guard 430 toward the protruding position. Namely, each roller guard 430 may be configured to, in response to the flap 120 swinging up, be pushed by the flap 120 and swung from the protruding position to the receding position. Further, each roller guard 430 may be configured to, in response to the flap 120 swinging down, be swung by an urging force of the spring from the receding position to the protruding position. Further, each roller guard 430 may be disposed to always contact the flap 120. In this case, each roller guard 430 may be configured to, in response to the flap 120 swinging up and down, be pushed by the flap 120 and swung between the protruding position and the receding position, owing to a change in a contact state (e.g., a contact area and a contact position) between the flap 120 and each roller guard 430.
In the aforementioned embodiment, in order to certainly establish contact between the later-ejected document sheet and the assist feed roller 300, the flap 120 is disposed to extend in the horizontal direction in the insertion mode, the fixed tray 110 is disposed to extend obliquely upward in the insertion mode, and the assist feed roller 300 is disposed at the upstream end of the fixed tray 110. However, for instance, a flap may be disposed to extend obliquely upward toward a downstream side in the insertion mode, a fixed tray may be disposed to extend obliquely upward at a greater angle in the insertion mode, and an assist feed roller may be disposed at an upstream end of the fixed tray.
In the aforementioned embodiment, the switching mechanism (the flap 120, the cam 410, and the roller guards 430) is configured to, depending on whether the ejection mode is set in the insertion mode or the stacking mode, switch the state of the assist feed roller 300 relative to the document sheet on the catch tray 100 between the contact state and the non-contact state. However, for instance, the switching mechanism may be configured to, depending on a sheet type or the number of sheets ejected on the catch tray 100, switch the state of the assist feed roller 300 relative to the document sheet on the catch tray 100 between the contact state and the non-contact state. Specifically, the switching mechanism may switch the state of the assist feed roller 300 relative to the document sheet on the catch tray 100 between the contact state and the non-contact state, when a user selects a predetermined type of sheet (e.g., a heavy type of sheet), or when the number of sheets ejected on the catch tray 100 exceeds a predetermined number.
In the aforementioned embodiment, in order to switch the ejection mode, the flap 120 is provided that switches the ejection mode between the insertion mode and the stacking mode along with a swing motion of the upstream end 122 of the flap 120 in the vertical direction. However, for instance, a flap may be employed that switches the ejection mode along with a vertical slide motion of the flap. Furthermore, a catch tray may be employed of which the position is fixed. In this case, ejection rollers may be provided that moves up and down to switch the ejection mode.
In the aforementioned embodiment, some aspects of the present invention are applied to the document feeder 1 configured to switch the ejection mode. However, aspects of the present invention may be applied to a sheet feeder or a sheet ejector configured to eject sheets only in the insertion mode.
In the aforementioned embodiment, the switching mechanism includes the cam 410, the flap 120, and the roller guards 430. However, for instance, the switching mechanism may include roller guards or an alternative switching member that is manually moved between the protruding position and the receding position. Further, an assist feed roller may be employed that is configured to move between a contact position where the assist feed roller contacts the sheet on the catch tray 100 and a non-contact position where the assist feed roller does not contact the sheet on the catch tray 100.
In the aforementioned embodiment, some aspects of the present invention are applied to the document feeder 1 configured with the catch tray 100 disposed above the feed tray 10. However, aspects of the present invention may be applied to a document feeder configured with a catch tray disposed under a feed tray. Further, aspects of the present invention may be applied to a sheet ejector of an image forming device such as a printer and a copy machine.
In the aforementioned embodiment, the switchback rollers 53 are exemplified as reverse rollers. However, ejection rollers for a document feeder or an image forming device may be employed as reverse rollers.
In the aforementioned embodiment, a document sheet with an image formed on each side or a single side thereof is exemplified as a sheet to be ejected. However, for instance, when aspects of the present invention are applied to an image forming device, a blank sheet or a transparent sheet (for an overhead projector) may be employed as a sheet to be ejected.
In the aforementioned embodiment, the assist feed roller 300 is configured to be driven to rotate when the motor 310 rotates in one direction and causes the switchback rollers 53 to rotate in such a direction as to pull back a document sheet. Further, the assist feed roller 300 is configured to be stopped when the motor 310 rotates in the other direction and causes the switchback rollers 53 to rotate in such a direction as to eject a document sheet.
However, for instance, when aspects of the present invention are applied to a printer configured to form an image on each side of a sheet, the assist feed roller 300 may be configured to be driven to rotate when a driving source rotates in one direction and causes ejection rollers (reverse rollers) to rotate in such a direction as to eject a sheet. Further, the assist feed roller 300 may be configured to be stopped when the driving source rotates in the other direction and causes the ejection rollers to rotate in such a direction as to pull back a sheet.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-129362 | May 2009 | JP | national |
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| 20070210512 | Sakakibara et al. | Sep 2007 | A1 |
| 20090324312 | Kusama | Dec 2009 | A1 |
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| Number | Date | Country | |
|---|---|---|---|
| 20100301544 A1 | Dec 2010 | US |
