JP3560803B2 - Automatic document feeder - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automatic document feeder mounted on a copying machine or the like.
[0002]
[Prior art]
In the conventional automatic document feeder, as shown in FIG. 5, the lower surface of the leading end of a document set on the document table is raised and lifted by the bottom plate 3 of the document table. Paper was being fed. At the time of sheet feeding, the sheet feeding pressure is generated by pinching the sheet feeding side end of the document between the pickup roller 7 and the bottom plate 3, and the pickup roller 7 is rotated in the pinching state, so Or the pickup roller 7, which is lowered by its own weight, lifts the bottom plate 3 by raising the bottom plate 3 with the set document sandwiched therebetween, and detects the appropriate position for feeding the topmost document. A configuration is known in which the pickup roller 7 is rotated in the sheet feeding direction, and the sheet is fed from the uppermost document by the conveyance force of the weight of the pickup roller 7. In such an apparatus, there is a gap between the bottom plate 3 and the document abutting surface 29C of the document abutting member (a part of the bottom plate stay 29), and when a weak original such as a thin original is fed, The paper feeding side end of the original or the lower original hangs down into the gap, and as a result, it is impossible to climb over the original abutting member, and there is a problem that the original is likely to be broken or jammed due to non-feeding. Such a problem also occurs when the original document itself has a back curl (a downward curl at the time of setting the original document, for example, a curl such that the end of the original on the paper feed side hangs down). Therefore, an apparatus has been proposed in which a gap between the bottom plate 3 and the document abutment member is eliminated by projecting a part (the dotted line portion 3a) of the bottom plate 3 forward of the document abutment member in the feeding direction. The document abutment surface 29C functions as a guide surface when the fed document is transferred from the bottom plate 3 of the document table to the upper feed guide plate 41. Further, the fed document is sent to the paper feeding belt 9 side, the paper feeding belt 9 is driven in the paper feeding direction, and the reverse roller 10 rotates in the reverse direction to the paper feeding direction, thereby performing a separating operation. ing.
[0003]
A related device of this type is, for example, JP-A-9-325531.
[0004]
[Problems to be solved by the invention]
In the conventional technique, a weakly stiff original or the original on the paper feed side hangs in a gap between the bottom plate 3 and the original butting member forming a part of the bottom plate stay 29 shown in FIG. Although it is possible to prevent the original having the original from entering, the back curl habit that both ends hang down from the center of the end of the original on the sheet feeding side is not sufficiently considered. For example, as shown in FIG. 6 (a), when both ends hang down from the center of the feed-side document end abutting on the document abutment surface 29C, or as shown in FIG. 6 (b). When the paper curls back and forth in the direction, and both ends hang down from the center of the paper end on the paper supply side, both ends of the paper end on the paper supply side abutting against the document abutting surface 29C are broken. There is a risk of doing. This is because, when a document as shown in FIGS. 6A and 6B is set, both ends of the document-feeding document end hang down from the central portion, so that the central portion has a back curl. Even if the back-curl is corrected by the feed pressure of the pickup roller 7 and the bottom plate 3 or the weight of the pickup roller 7, the back curl can be corrected and the sheet can move in the direction of the feed belt over the document abutting surface 29 </ b> C. Is suspended by the back curl, so that it is difficult to get over the original abutting surface 29C.
[0005]
A first object of the present invention is to solve such a problem, and when a document has a back curl habit, for example, both ends of a feed-side document end abutting against a document abutting member are directed downward more than the center portion. An object of the present invention is to provide an automatic document feeder that does not cause a problem such as breakage when the document feed side document end passes through a document abutting member even when the document is curled. It is a second object of the present invention to provide an automatic document feeder capable of replacing a document abutting member in addition to the first object. Further, a third object of the present invention is that, in addition to the second object, an original having a weak stiffness or an original having a pack curl habit such that the paper supply side end hangs down is formed between the bottom plate and the original abutting member. An object of the present invention is to provide an automatic document feeder capable of preventing entry into a gap.
[0006]
[Means for Solving the Problems]
[0007]
In order to achieve the above object, an automatic document feeder of the present invention includes a document table for setting a document bundle, a pickup roller for feeding a topmost document of the document bundle set on the document table, A document abutting member disposed orthogonal to the document feeding direction and having a document abutting surface against which a paper-feeding end surface of the bundle of documents set on the document table abuts; It is configured such that the height of the document abutting surface is different between a portion where the central portion of the document end on the sheet feeding side when the roller feeds and a portion where both ends of the document side on the sheet feeding side abut , An upper portion of the document abutting surface has an inclined surface having an angle different depending on the height of the document abutting surface .
[0008]
Furthermore , at least a part of the butting member is configured to be detachable.
Furthermore, a bottom plate for lifting the bundle of documents set on the document table upward is provided, and at least a portion of the bottom plate is configured to protrude from the document abutting surface in the sheet feeding direction.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an outline of an automatic document feeder according to a first embodiment of the present invention, FIG. 2 is a diagram showing a document setting section in the automatic document feeder of FIG. 1, and FIG. FIG. The automatic document feeder 1 according to the present embodiment is installed on a copying machine main body, and includes a paper feed unit 100, a transport unit 200, and a paper discharge unit 300. Each unit is driven by independent driving means (sheet feeding motor, conveying motor, sheet discharging motor, not shown).
[0010]
The document setting unit (FIGS. 2 and 3) in the paper feeding unit 100 is integrated with the document table 2 for setting a document, the bottom plate 3 and the bottom plate stay 29 included in the document table 2, and is used for setting a document. A document abutting member (including a document abutting surface 29A, inclined surfaces (hereinafter, referred to as guide surfaces) 29B and 29b, and the like) is provided so as to be perpendicular to the paper feeding direction such that an edge of the document on the paper feeding side abuts.
[0011]
In the present embodiment, an original is set on the original table 2 including the bottom plate 3 with the image surface (front surface) facing upward. The bottom plate 3 is rotatably mounted around a rotation fulcrum 28 on a bottom plate stay 29 mounted between front and rear side plates (not shown) of the automatic document feeder 1. The bottom plate 3 is configured to be able to move up and down in the directions a and b in FIG. Further, in the same manner as in the prior art, the document table 2 is provided for preventing the folded or non-feeding of the fed document in response to the case where the center and both ends of the feeding-side document end having a back curl are hanging down. At least a part of the bottom plate 3 is configured to protrude from the document abutting member in the sheet feeding direction. A document set sensor 5 for detecting that a document has been set on the document table 2 and a set document for detecting that the sheet feeding side end of the set document has hit the document abutting member are provided on the bottom plate 3 side. Detecting fillers 4 are arranged, which rise and fall together with the bottom plate 3. Further, a descent position detecting sensor 6 is arranged on the bottom plate stay 29 side, and detects that the bottom plate 3 has been lowered to a predetermined position.
[0012]
The document abutment member is a part of the bottom plate stay 29, has a document abutment surface 29A and guide surfaces 29B and 29b, and is integrally formed with the bottom plate stay 29. In this case, it is also assumed that a document abutting surface (corresponding to 29a in FIG. 4) having a height different from that of the document abutting surface 29A is also provided. In addition, the original attaching member is integrally formed on the bottom plate stay 29 on the side of the separation nip portion composed of the paper feed belt 9 and the reverse roller 10. The guide surfaces 29B and 29b for delivering the original are formed on the upper paper feed guide plate 41 for guiding the original to the copy unit. In the present embodiment, the height of the document-attaching member is higher at the center near the paper feeding means (pickup roller 7) for feeding the document from the bottom plate 3 of the document table 2, and lower at both ends. It is configured with at least two or more heights. That is, of the document abutting surface, a portion (corresponding to the document abutting surface 29a shown in FIG. 4) where the central portion of the paper feed side document end when the pickup roller 7 feeds from the bottom plate 3 of the document table 2 abuts. The height of the document is higher than the height of the portion (document abutment surface 29A) where the both ends of the document-side document end abut. Further, the inclination angles of the guide surfaces 29B and 29b from the bottom plate 3 of the document table 2 to the upper paper feed guide plate 41 are configured to be different according to the height of the contact surface with the document. For example, when the guide surface is configured with two types of original contact surfaces, the guide surface has a large inclination angle at a higher portion (corresponding to the original contact surface 29a shown in FIG. 4) of the original contact surfaces. , And a guide surface 29B having a small inclination angle is arranged on the lower portion (document abutment surface 29A). Therefore, the central portion of the paper feed side document end having the back curl is corrected by the weight of the pickup roller 7 which is lowered as described later, and easily passes over the document attaching member. On the other hand, the hanging both ends of the feed-side document end having a back curl are formed in a portion of the document attaching member that has a gentler gradient than the central portion (a portion having the document abutting surface 29A and the guide surface 29B). Since it abuts, it is possible to easily get over the original attaching member. In this embodiment, the original attaching member is integrally formed with the bottom plate stay 29. However, as another embodiment, as shown in FIG. 4, the original attaching surfaces 29A and 29a (the guide surfaces 29B and 29b are not used). (Included) may be assembled to the bottom plate stay 29 with fastening parts such as screws to be detachable. Alternatively, a part of the document attaching member 42 may be detachable. Further, the form of the document-attached contact member 42 is determined by the height of the document-attached contact surfaces 29A and 29a and the inclination angles of the guide surfaces 29B and 29b so as to correspond to the type of curl, paper quality, etc. of the document actually used. However, it is also possible to prepare a plurality of types different from each other to keep the replacement parts cost low.
[0013]
The pickup roller 7 in the sheet feeding unit 100 is lifted in the direction c by a lever by a lever by a rotation of a cam (not shown) by a pickup roller raising motor (not shown). When a document is set on the bottom plate 3 and a copy start button (not shown) on the copying machine main body side is pressed, the bias in the direction c by the lever is released by the rotation of the cam by the pickup roller raising motor, The pickup roller 7 descends in the d direction by its own weight. Thereafter, the bottom plate 3 is raised, and the pickup roller 7 comes into contact with the upper surface of the original on the bottom plate 3 and is pushed up in the direction c. The appropriate paper feed position sensor 8 detects the height of the pickup roller 7 and determines the raised position of the bottom plate 3. decide. That is, the height of the uppermost document of the set document is detected, and an appropriate position for transporting the uppermost document to the paper feed port is determined. The pickup roller 7 is rotated by the paper feed motor in a paper feed direction (a direction in which the uppermost document is conveyed to a paper feed port).
[0014]
The paper feed belt 9 in the paper feed unit 100 is driven in the paper feed direction by the paper feed motor, and the reverse roller 10 is driven to rotate in the direction opposite to the paper feed direction by the paper feed motor. It is configured to perform an operation (separation operation) of reversing a lower document and feeding only the uppermost document to the document. The pull-out roller 11 is used to convey the document conveyed by the paper feed belt 9 to the registration rollers 13 after the document is separated, and is driven by the paper feed motor. The pull-out sensor 12 is also used to detect the original conveyed by the pull-out roller 11 with an optical reflection sensor and to detect the length of the original from the motor pulse by reading the trailing end of the original. Can be The registration roller 13 is also driven by the paper feed motor, and conveys the document onto the contact glass 31. The registration sensor 15 is an optical reflection type sensor that detects the document conveyed by the registration roller 13, and serves as a timing sensor for stopping the document on the contact glass 31.
[0015]
In the transport unit 200, an endless belt 17 made of rubber or cloth is stretched over the transport belt drive roller 16, and the transport motor drives the transport belt drive roller 16 to rotate the transport belt 17 in contact therewith. It is configured to be driven. The transport belt 17 is in contact with the original scale 32 and the contact glass 31, and the original enters between the contact glass 31 and the transport belt 17. The original is the friction coefficient between the contact glass 31 and the original and between the transport belt 17 and the original. Is conveyed over the contact glass 31 by the difference.
[0016]
Further, the original scale 32 is configured so that its end is slightly higher than the upper surface of the contact glass 31, and the end of the original is brought into contact with the end of the original scale 32 to set the original. Images can be read. The scanner 30 is located in the scanner unit on the copying machine main body side, and scans a document from below the contact glass 15 to read image data by an optical element such as a CCD. The scanner 30 is driven by a scanner motor (not shown) on the copying machine main body side to scan a document and move a scanning position.
[0017]
Further, in the paper discharge unit 300, the paper discharge unit entrance sensor 19 is an optical reflection type sensor and detects a document conveyed by the conveyance belt 17. Further, the paper discharge unit entrance roller 18, the single-sided paper discharge roller 20, and the double-sided paper discharge roller 25 are all driven by the paper discharge motor. The paper ejection sensor 22 is an optical reflection sensor, which is used as a trigger for controlling the timing of changing the paper ejection switching claw 21 at the time of reversal and double-sided paper ejection, and changing the paper ejection reversal switching claw 24 at the time of double-sided paper ejection. Used as a trigger for timing control. The single-sided paper output tray 27 is a paper-output tray for the single-sided copying mode attached to the main body of the copying machine (the right side in FIG. 1), and the double-sided paper output tray 26 is provided below the document table 2. These are discharge trays for the duplex copying mode, which hold originals ejected in the simplex / duplex copying mode.
[0018]
With this configuration, in the one-sided copying mode in the present embodiment, when a document is set on the document table 2 and the copy start button is pressed, the paper feed motor rotates forward (clockwise), and the pickup is picked up. The roller 7, the feed belt 9, and the pull-out roller 11 rotate forward, and the reverse roller 10 rotates backward (counterclockwise). The document set on the document table 2 is fed from the uppermost document by the forward rotation of the pickup roller 7 descending in the direction d as described above, and is fed by the forward rotation of the feed belt 9 and the reverse rotation of the reverse roller 10. The sheets are separated one by one and pulled out by the pull-out roller 11. The original conveyed by the pull-out roller 11 is conveyed to the registration roller 13 after the leading and trailing edges are detected by the pull-out sensor 12. When the registration sensor 15 detects the leading edge of the original, the driving direction of the paper feed motor is switched from forward rotation to reverse rotation, and the pickup roller 7 and the paper feed belt 9 are stopped by a drive system (not shown), and the pull-out is performed. The roller 11 rotates forward and the reverse roller 10 rotates reversely. This control prevents the next document from entering the separation nip portion composed of the feed belt 9 and the reverse roller 10, and conveys only the current document from the pull-out roller 11 to the registration roller 13. The conveyance motor rotates forward simultaneously with the reverse rotation of the paper feed motor, and the document is conveyed onto the contact glass 31 by the conveyance belt 17. At this time, after the registration sensor 15 detects the rear end of the document conveyed by the registration roller 13, the conveyance motor is driven by a predetermined number of pulses to convey the document, and thereafter, the conveyance motor is stopped. Then, the original is set on the contact glass 31. The document on the contact glass 31 is conveyed to the sheet discharge unit 300 by the conveyance belt 17 by the reverse rotation of the conveyance motor after the exposure operation by the scanning of the scanner 30 is completed. In the paper discharge unit 300, the paper discharge motor rotates reversely at the same time as the reverse rotation of the transport motor, and the original conveyed to the paper discharge unit 300 is discharged to the single-sided paper output tray 27 without being inverted. You. When a single-sided document is discharged in this way, the discharge switching claw 21 is switched by a reversing solenoid (not shown) so that the document is transported and guided in the direction e. That is, the switching claw 21 is retracted upward, and the lower surface of the switching claw 21 functions as a transport guide. In this way, the original is conveyed to the paper discharge section by the entrance roller 18 and the single-sided paper discharge roller 20 and discharged onto the single-sided paper discharge tray 27. In the double-sided copying mode, the paper feeding operation is the same as in the single-sided copying. In the case of paper ejection, when the two-sided original is inverted and conveyed onto the contact glass 31, the paper ejection switching claw 21 is switched so that the original is conveyed in the f direction, and the paper ejection reversal switching claw 24 is turned on. The document is switched by the reversing solenoid (not shown) so that the document is conveyed in the h direction. In this state, the original is conveyed by the discharge unit entrance roller 18, the image surface is inverted, and is sent onto the contact glass 31. After the image data on the image side (back side) of the inverted document is read by the scanner 30, the document is conveyed again from the conveyance unit 200 to the paper discharge unit 300. When the inverted document is discharged to the single-sided discharge tray 27, the page order of the bundle of documents is reversed, and the reversed document is discharged onto the double-sided discharge tray 26. At this time, the paper discharge switching claw 21 is switched so that the original is transported in the f direction, and the paper discharge reversal switching claw 24 is switched so that the original is transported in the g direction. The sheet is discharged onto a two-sided sheet discharge tray 26 by a two-sided sheet discharge roller 25.
[0019]
According to the present embodiment, the height of the portion of the document abutting surface where the central portion on the paper feeding side of the fed document abuts, that is, the height of the document abutting surface 29a near the pickup roller 7 is set to Since the height of the document abutting surfaces 29A at both ends of the document end is higher than the height of the document abutment surface 29A, even when a document having a larger back curl amount at both ends than the center of the document side at the sheet feeding side is fed, Both end portions can easily get over the document abutting member. Therefore, when the fed document passes through the document abutting member, a problem such as breakage at the both ends does not occur. Further, since the upper portions of the document abutting surfaces 29A and 29a have an inclination corresponding to the height thereof (in the present embodiment, the inclination angle of the guide surface 29B <the inclination angle of the guide surface 29b), the document end on the sheet feeding side is provided. Even when a document having a larger back curl amount at both ends than the central portion is fed, the both ends can easily get over because they abut a guide surface which is lower than the central portion and has a gentle inclination. Therefore, when the fed document passes through the document abutting member, a problem such as breakage at the both ends does not occur.
[0020]
Further, according to the present embodiment, at least a part of the abutting member 42 is configured to be detachable, so that the original abutting member having a shape corresponding to the back curl amount of the actually used original can be appropriately replaced. Can be used. Therefore, it is possible to efficiently assemble replacement parts while suppressing an increase in cost.
Further, according to the present embodiment, at least a portion of the bottom plate 3 is configured to protrude from the document abutting surfaces 29A and 29a in the sheet feeding direction. It is possible to prevent a weak document or a document having a pack curl habit from falling into the paper feed side end.
[0021]
【The invention's effect】
As described above, according to the present invention, the height of a portion (near the pickup roller) of the document abutting surface where the central portion on the sheet feeding side end of the document fed from the document table by the pickup roller abuts, Since the height of the other portion of the original abutting surface is configured to be different depending on the amount of back curl of the original, if the original has a back curl, for example, both ends from the center of the original end on the sheet feeding side Even when a document having a large back curl amount is fed, no problem such as breakage occurs when the fed document passes through the document abutting member. Further, since the upper surface of the document abutting surface has an inclined surface having a different angle depending on the height, the both ends abut against a gentle and inclined surface having a height corresponding to the back curl amount, and Problems such as breakage do not occur when passing through the member.
[0022]
Further, according to the present invention, at least a part of the abutting member is configured to be detachable, so that the original abutting member having a shape corresponding to the back curl amount of the actually used original can be appropriately replaced. Can be used. Therefore, it is possible to efficiently assemble replacement parts while suppressing an increase in cost.
Furthermore, according to the present invention, at least a portion of the bottom plate is configured to protrude from the document abutting surface in the sheet feeding direction. possible to prevent the document having a bar Kkukaru habit such as hanging the end enters.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an outline of an automatic document feeder according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a document setting section in the automatic document feeder of FIG. 1;
FIG. 3 is a plan view of FIG. 2;
FIG. 4 is a diagram illustrating a configuration of a document butting member of an automatic document feeder according to a second embodiment of the present invention.
FIG. 5 is a diagram showing a document setting section in a conventional automatic document feeder.
FIG. 6 is a diagram illustrating a back curl habit of a document.
[Explanation of symbols]
2 Document table 3 Bottom plate 7 Pickup roller 29 Bottom plate stays 29A, 29a Document abutment surfaces 29B, 29b Guide surface 42 Document abutment member

Claims (3)

A document table for setting a bundle of documents,
A pick-up roller for feeding the uppermost document of the document bundle set on the document table,
A document abutting member disposed orthogonal to the document feeding direction and having a document abutting surface against which a paper feeding side end surface of the document bundle set on the document table abuts;
The document abutting member has a height of the document abutting surface at a portion where the central portion of the document side at the time of feeding by the pickup roller abuts and at a portion where both ends of the document end at the sheet feeding side abut. Are configured to be different,
An automatic document feeder, characterized in that an upper surface of the document abutting surface has an inclined surface having a different angle depending on the height of the document abutting surface . 2. The automatic document feeder according to claim 1, wherein at least a part of the abutting member is configured to be detachable . 3. The image forming apparatus according to claim 2 , further comprising: a bottom plate that lifts up a bundle of documents set on the document table, wherein at least a part of the bottom plate protrudes from the document abutting surface in a sheet feeding direction. Automatic document feeder as described.

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