JP2008254896A - Sheet feeder, document feeder and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeder capable of preventing a feeding trouble at low cost by detecting an excess of loading quantity of sheets without providing a special part. <P>SOLUTION: This document (sheet) feeder 10 includes: a document feeding tray 11; a document feeding mechanism 12 to feed documents one by one from the document feeding tray 11; a device case body 21 to support the document feeding tray 11 free to move in the vertical direction; a tray driving mechanism 24 to move the document feeding tray 11 in the vertical direction; a document set detection sensor 31 to detect loading of the documents on the document feeding tray 11; a document position detection sensor 33 to detect that the document at the top level is positioned at a position free to feed the documents; and a controller 32 to determine it an excess of loading quantity when the document set detection sensor 31 and the document position detection sensor 33 come to be in a detecting state before the document feeding tray 11 moves in an upward direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sheet feeding device such as a document feeding device and an image forming apparatus including the same.

  Some image forming apparatuses such as copying machines are provided with a sheet feeding device that stacks sheets on a tray provided outside the image forming apparatus and sequentially feeds (conveys) the sheets. As this paper feeding device, for example, a document feeding device that sequentially feeds a sheet-like document to the document placing table to expose it, and discharges it from the document placing table after the exposure is completed. A manual feed device that sequentially feeds images to the image forming unit to form an image from the side of the forming device, and a front and back paper (cover paper) and identification used during bookbinding between normal paper that is carried from the image forming device For example, there is an insert device for inserting an insertion sheet such as a slip sheet (insert sheet).

  In such a sheet feeding apparatus, it is necessary to separate and convey originals or sheets one by one accurately, and various apparatuses have been proposed.

  For example, according to Patent Document 1, a stacking restriction portion is disposed above the manual feed tray at a position that interferes with a predetermined number or more of the paper manually fed to the manual feed tray, and is inclined toward the entering paper. The sheet regulating surface to be formed is formed in a portion that interferes with the sheet of the load amount regulating section, and the sheet regulating surface regulates the entry of more than the prescribed number of sheets.

  Further, for example, according to Patent Document 2, an operation enable / disable signal is transmitted from the main body to the automatic document feeder, and the automatic document feeder is only in a state where the main body is operable and a document set sensor detects a document set. A sheet feeding preparation operation such as ascending is performed, and the sheet feeding operation is started by a sheet feeding start signal from the main body. When the mixed loading mode is selected on the operation unit of the main body, the automatic document feeder does not perform a paper feeding preparation operation when a document set is detected, and starts a paper feeding preparation operation in response to a paper feeding start signal from the main body.

Further, for example, according to Patent Document 3, it has a document set detection sensor that detects that a document is set on a document table, and when the sensor detects that a document is set on the document table, By a calling roller that presses near the front end of the lower surface of the original bundle, the originals are sequentially called from the lower side of the original bundle, and a pull-out roller provided on the downstream side of the original bundle and a separation belt that is wound around the original conveyance path and reversed or stationary In an automatic document feeder that separates multiple feeds and feeds documents to an exposure position, a document stack limit detection sensor that detects that a stack of documents set on the document table exceeds the stack limit And a warning means for giving a warning when the sensor detects that the number of stacked document bundles exceeds the limit number. Automatic original feeding apparatus is disclosed which is adapted to prohibit the operation of the limit number exceeded sensing automatic document feeder.
Japanese Patent Laid-Open No. 9-240887 JP 2000-53255 A Japanese Utility Model Publication No. 4-63452

  However, according to Japanese Patent Laid-Open No. 2004-228867, the load amount regulation unit regulates more than the specified number of sheets. However, if the user forcibly inserts more than the specified number of sheets, the sheet may be damaged. Further, when the paper is sent out by the paper feeding means, the contact with the upper guide member becomes a load, and there is a possibility that poor feeding or oblique paper feeding may occur.

  Further, according to Patent Document 2, when it is detected that a document is set by the document set sensor, it is determined that preparation for document feeding start is complete even when the document stacking amount exceeds the specified amount. Therefore, there is a possibility that a paper feeding trouble may occur.

  According to Patent Document 3, a dedicated component called a document stacking limit limit detection sensor is provided in order to detect that the stack of documents set on the document table exceeds the stacking limit number of sheets. It leads to.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a paper feeding apparatus that detects an excess of paper stacking capacity and prevents a paper feeding trouble at a low cost without providing a dedicated part.

  In order to achieve the above object, a paper feeding device according to the present invention includes a paper stacking unit on which paper is stacked, a paper feeding mechanism that feeds paper one by one from the paper stacking unit in a predetermined transport direction, An apparatus housing that supports the paper stacking unit so as to be movable in the vertical direction; a drive mechanism that moves the paper stacking unit in the vertical direction; a paper stacking detection unit that detects stacking of paper on the paper stacking unit; When the sheet stacking unit moves upward, a sheet position detecting unit that detects that the uppermost sheet is positioned at a sheet feedable position; and before the sheet stacking unit moves upward, the sheet And a control unit that determines that the stacking amount is exceeded when the stack detection unit and the sheet position detection unit are in the detection state.

  According to this configuration, the control unit determines whether or not a sheet exceeding the maximum load amount is loaded on the sheet stacking unit using the detection results of the sheet stacking detection unit and the sheet position detecting unit.

  In the sheet feeding device, the control unit prohibits the operations of the sheet feeding mechanism and the driving mechanism when it is determined that the stacking amount is exceeded. According to this configuration, it is possible to reliably prevent paper feeding troubles.

  In the paper feeding apparatus, the control unit outputs a warning when it is determined that the stacking amount is exceeded. As a warning output destination, a light emitting means or a display means of the image forming apparatus can be used.

  Further, the paper feeding device can be a document feeding device that feeds a document.

  An image forming apparatus according to the present invention includes the above sheet feeding device.

  The image forming apparatus according to the present invention includes a paper stacking unit on which paper is stacked, a paper feeding mechanism that feeds the paper one by one from the paper stacking unit in a predetermined transport direction, and the paper stacking unit that moves up and down. An apparatus housing that is movably supported in a direction, a drive mechanism that moves the paper stacking unit in the vertical direction, a paper stacking detection unit that detects stacking of paper on the paper stacking unit, and the paper stacking unit A sheet feeding device having a sheet position detecting means for detecting that the uppermost sheet is positioned at a sheet feeding enabled position when moved in the direction, and before the sheet stacking unit moves upward. And a control unit that determines that the stacking amount is exceeded when the sheet stacking detection unit and the sheet position detecting unit are in a detection state.

  According to this configuration, since the control unit that also controls the paper feeding device is provided in the image forming apparatus, the control unit is not required in the paper feeding device, and the cost can be reduced.

  According to the present invention, the control means determines whether or not the paper exceeding the maximum load capacity is loaded on the paper stacking unit using the detection results of the paper stack detecting means and the paper position detecting means that are conventionally used. Therefore, it is possible to prevent a paper feeding trouble at a low cost without providing a dedicated part for detecting an excess load.

  FIG. 1 is a cross-sectional view illustrating an example of a document feeding device in a state where a first tray unit is in an initial position. A document feeding device (paper feeding device) 10 is used together with an image forming apparatus (for example, a copying machine), and is disposed on an upper surface side of a main body of an image forming apparatus (not shown). The document feeder 10 includes a document feed tray (paper stacking unit) 11 and a document feed mechanism (paper feed mechanism) 12, and a bundle of documents is stacked on the document feed tray 11. . The document feeding mechanism 12 separates the documents one by one from the bundle of documents stacked on the document feeding tray 11, and conveys the documents to the first image reading position GP1.

  Then, after an image on one side of the original is read by the first scanner unit (not shown) at the first image reading position GP1, the original is sent to the second original reading position GP2, and then the second image reading position GP1. An image on the other side of the document is read by the scanner unit 13. Then, the document is discharged by a pair of discharge rollers 16 to a document discharge tray 15 disposed below the document feed tray 11.

  The document feeder 10 shown in FIG. 1 is compatible with double-sided printing. When single-sided printing is performed, for example, an image on a document is read only at the first image reading position GP1. Although not shown, in the image forming apparatus, an image carrier such as a photosensitive drum is exposed based on image data obtained by reading a document, and an electrostatic latent image is formed on the image carrier. . Then, after the electrostatic latent image is developed by the developing device, the toner image on the image carrier is transferred to the recording paper, the toner image on the recording paper is fixed, and the paper is discharged onto a paper discharge tray.

  As shown in FIG. 1, the document feeding mechanism 12 is disposed on the downstream side of the document feeding tray 11 in the document transport direction. The document feeding mechanism 12 includes a document feeding roller unit (hereinafter simply referred to as a sheet feeding roller unit). The document feed roller section 14 includes a roller housing 14a, a pickup roller (pickup roller) 14b, a feed mechanism 14c, and a separation roller 14d.

  The feed mechanism 14 c includes a pair of feed rollers (feed rollers) 141, a feed belt 142 is stretched around the feed rollers 141, and a separation roller 14 d is in contact with the feed belt 142. The pickup roller 14b and the feed mechanism 14c are housed in a roller housing 14a, and the separation roller 14d is provided on the base side of the document feeding mechanism 12. Instead of the above-described feed mechanism 14c, a single feed roller 141 may be provided, and the feed roller 141 may be disposed to face the separation roller 14d.

  The document feed tray 11 includes a first tray portion 11a located on the document feed mechanism 12 side (that is, a downstream side in the document conveyance direction) and a second tray portion 11b located on the upstream side in the document conveyance direction. The second tray portion 11b is rotatably mounted on an automatic document feeder housing (hereinafter simply referred to as a device housing) 21.

  The first tray section 11a is attached to the apparatus casing 21 so as to be movable in the vertical direction in the figure (the direction indicated by the solid line arrow in the figure) with respect to the apparatus casing 21. A bridging portion 11c is attached to the upstream end in the direction so as to be rotatable about a fulcrum shaft 22 extending in the width direction of the apparatus housing 21, and a portion of the bridging portion 11c on the upstream side in the document conveying direction is It is in contact with the upper surface of the second tray portion 11b.

  Further, the second tray portion 11b forms an inclined surface 11d whose upper surface is inclined obliquely downward at the downstream side in the document conveying direction, and the bridging portion 11c upstream of the document conveying direction on the inclined surface 11d. The side part is in contact. A document guide 23 for defining the document width is provided on the upper surface of the first tray unit 11a. The first tray unit 11a is fixedly attached to the document feeding mechanism 12, and the first tray unit 11a The downstream end in the document transport direction is located downstream of the pickup roller 14b.

  The first tray portion 11a is driven upward from the reference position (initial position) shown in FIG. When the first tray portion 11a is at the reference position, as shown in FIG. 1, the lower surface of the bridging portion 11c is in contact with the inclined surface 11d, and the first tray portion 11a It is located below the second tray portion 11b.

  Now, referring also to FIG. 2, when a bundle of documents is stacked (set) on the document feed tray 11, a document set is detected by a document set detection sensor (paper stack detection means) 31 (not shown in FIG. 1). The document set detection sensor 31 turns on a document set detection signal (that is, sends a document set detection signal to the controller 32). When the copy button (copy button) 35 of the image forming apparatus is operated, the controller (control means) 32 controls the tray driving mechanism 24 to drive the first tray portion 11a by the tray driving mechanism 24. The first tray portion 11a is raised from the initial position.

  When the uppermost document comes into contact with the pickup roller 14b, the pickup roller 14b is pushed upward, and the pickup roller 14b is a document position detection sensor (paper position detection means) 33 (not shown in FIG. 1). ) Is shielded, the document position detection sensor 33 detects it. When the document position detection sensor 33 detects (that is, the document position detection sensor 33 detects the document at the uppermost position), the document position detection sensor 33 turns on the document position detection signal (that is, the controller 32). Send a document position detection signal to the In response to the document position detection signal, the controller stops the tray driving device 24 so that the uppermost document is in contact with the pickup roller 14b (the uppermost document is in contact with the pickup roller 14b). The state is hereinafter referred to as a document feedable position).

  Subsequently, the controller 32 drives the document feeding mechanism 12 to start the document feeding operation, the document is picked up by the pickup roller 14b, and the document picked up by the pickup roller 14b by the separation roller 14d is one sheet. Are separated and fed downstream by the feed mechanism 14c.

  As shown in FIG. 1, the document feeding mechanism 12 has a document feeding section 20 disposed on the downstream side of the feed mechanism 14c. The document feeding section 20 includes a large-diameter driving roller 25 and a small-diameter driving roller 25. The driven rollers 26 and 27 are provided, and the peripheral surfaces of the driven rollers 26 and 27 are in contact with the peripheral surface of the drive roller 25. Then, the document is sent to the first document reading position GP1 by the document feeding section 20, and then passes through the second document reading position GP2 and is discharged to the document discharge tray 15.

  As the document is fed, the number of documents on the document feed tray 11 decreases. As described above, the document position detection sensor 33 detects the uppermost document on the document feed tray 11, and this In accordance with the detection result, the controller 32 controls the tray driving mechanism 24 to always position the uppermost document at the same position with respect to the pickup roller 14b (that is, the uppermost document is positioned at a document feedable position). ). At this time, the bridging portion 11c rotates around the fulcrum shaft 22 in the direction indicated by the dashed arrow (clockwise) as the first tray portion 11a rises, as if the bridging portion 11c is upstream in the document conveyance direction. It will turn as if it is a fulcrum.

  FIG. 3 shows the position of the first tray portion 11a in a state where all the documents on the document feed tray 11 are fed. In this state, the upper surface of the first tray portion 11a is the pickup roller 14b. It will be in the state close to. When all the documents are fed, the document set detection sensor 31 turns off the document set detection signal. Accordingly, the controller 32 controls the tray driving mechanism 24 to move the first tray portion 11a downward and return it to the reference position (initial position).

  As shown in FIG. 3, the tray drive mechanism 24 described above has a rotating shaft body 24a extending in the width direction of the apparatus housing 21 and a driving stay portion 24b having one end attached to the rotating shaft body 24a. The stay portion 24b extends in the document transport direction along the lower surface of the first tray portion 11a. When the rotary shaft body 24a is rotationally driven, the drive stay portion 24b rotates about the rotary shaft body 24a, and thereby the first tray portion 11a moves upward. Further, the tray driving mechanism 24 has a guide portion 241, and the first tray portion 11 a is guided in the vertical direction by the guide portion 241. Specifically, the guide unit 241 includes a rack 24c and a pinion 24d, the pinion 24d is disposed on the lower surface of the first tray unit 11a, and the rack 24c is disposed on the apparatus housing 21 side. 24c and the pinion 24d are meshed.

  When the rotating shaft body 24a is rotated forward, the first tray portion 11a moves upward by the rotation of the drive stay portion 24b. At this time, the first tray portion 11a moves upward while being guided by the rack 24c and the pinion 24d. On the other hand, when the rotary shaft body 24a is rotationally driven in the reverse direction, the first tray portion 11a moves downward by the rotation of the drive stay portion 24b. Also at this time, the first tray portion 11a moves downward while being guided by the rack 24c and the pinion 24d.

  As described above, the document feed tray 11 includes the first tray portion 11a positioned on the document feeding mechanism 12 side (downstream side in the document transport direction) and the second tray portion 11b positioned on the upstream side in the document transport direction. In other words, only the first tray portion 11a is moved in the vertical direction according to the number of documents, and the uppermost document end is brought into contact with the pickup roller 14b. Considering that it is applied to the entire first and second tray portions 11a and 11b, the load applied to the first tray portion 11a is reduced, and a drive source for driving the first tray portion 11a is reduced accordingly. It can be downsized.

  Further, a bridging portion that is rotatable around a fulcrum shaft provided at the upstream end in the document transport direction of the first tray portion 11a is disposed between the first tray portion 11a and the second tray portion 11b. Therefore, even if the first tray portion 11a is driven in the vertical direction, the communication with the first and second tray portions 11a and 11b is maintained well, and document feeding is not hindered. .

  Further, the document feeder 10 detects a stack of documents that exceeds the maximum stacking capacity of the document feed tray 11 to prevent a feeding trouble. Specifically, when the document set detection sensor 31 and the document position detection sensor 33 are in a detection state (detection signal is on) before the document feed tray 11 moves upward, the controller 32 exceeds the stacking amount. It is judged that. Such a state occurs when the user pushes the leading end of the bundle of documents under the pickup roller 14b in order to load a document exceeding the maximum stacking amount on the document feed tray 11. That is, when the document bundle is pushed under the pickup roller 14 b, the pickup roller 14 b is pushed up and detected by the document position detection sensor 33. When a document is fed in this state, a large load is applied to the pickup roller 14b, so that there is a high possibility that a feeding trouble such as feeding failure or oblique feeding will occur.

  Therefore, when the controller 32 determines that the stacking amount is exceeded, the operation of the document feeding mechanism 12 and the tray driving mechanism 24 is prohibited. Then, the controller 32 outputs a warning. As a warning output destination, a light emitting means (not shown) such as an LED provided in the apparatus housing 21, a display means (not shown) such as a liquid crystal panel provided in the image forming apparatus, and a speaker (not shown). )and so on.

  Then, if the user removes all the documents on the document feed tray 11 so as to be less than or equal to the maximum loading amount, the document position detection sensor 33 is in a non-detection state, so the controller 32 stops the above warning, Return to normal operation.

  An example of excess loading will be described with reference to FIGS. FIG. 4 is a diagram schematically illustrating a state in which a small amount (less than the maximum stacking amount) of documents is set on the document feeding device 10, and FIG. 5 illustrates a large amount (greater than the maximum stacking amount) on the document feeding device 10. FIG. 6 is a diagram schematically showing a state in which a document is set.

  For example, description will be made assuming that the maximum document stacking capacity of the document feed tray 11 is 100 sheets, the document stacking capacity shown in FIG. 4 is 20 sheets, and the document stacking capacity shown in FIG. As shown in FIG. 4, when the document set on the document feed tray 11 is less than the maximum stacking amount, the detection signal of the document set detection sensor 31 is turned on and the detection signal of the document position detection sensor 33 is turned off. Since there is no problem in this case, when the copy button 35 of the image forming apparatus is operated, the controller 32 controls the tray driving mechanism 24 to raise the first tray portion 11a from the initial position.

  Then, when the document at the uppermost position comes into contact with the pickup roller 14b and the pickup roller 14b is pushed upward, and the pickup roller 14b shields the document position detection sensor 33, the document position detection sensor 33 detects it and sets the document. Send detection signal. Upon receiving the signal, the controller 32 stops the tray driving device 24 so that the uppermost document is in contact with the pickup roller 14b (document feedable position). Subsequently, the controller 32 drives the document feeding mechanism 12 to start a document feeding operation, operates each part below to transport the document, and discharges it to the document discharge tray 15.

  On the other hand, as shown in FIG. 5, when the document set on the document feed tray 11 exceeds the maximum loading capacity, detection signals of the document set detection sensor 31 and the document position detection sensor 33 at the time when the document is set. Is turned on. As described above, when the user tries to load a document exceeding the maximum load capacity on the document feed tray 11, the pickup roller 14b is pushed up by pushing the leading end of the document bundle under the pickup roller 14b, thereby detecting the document position. This is because it is detected by the sensor 33.

  In this case, the controller 32 determines that the stacking capacity is exceeded, stops the operation command to the document feeding mechanism 12 and the tray driving mechanism 24, and displays, for example, “Overloading capacity” as a warning message on the liquid crystal panel of the image forming apparatus. Please remove the original "message.

  When all the documents on the document feed tray 11 are removed by the user, the detection signals of the document set detection sensor 31 and the document position detection sensor 33 are turned off. If 20 or more originals exceeding the load capacity are removed, the detection signal of the original position detection sensor 33 is turned off while the detection signal of the original set detection sensor 31 is on. In any of these states, the controller 32 deletes the warning message on the liquid crystal panel, cancels the stop of the operation command to the document feeding mechanism 12 and the tray driving mechanism 24, and returns to the normal operation.

  As described above, the controller 32 uses the detection signals of the document set detection sensor 31 and the document position detection sensor 33 that have been used conventionally to check whether or not a document exceeding the maximum load capacity is loaded on the document feed tray 11. Therefore, it is possible to prevent a paper feeding trouble without providing a dedicated part for detecting an excess load.

  In the above-described embodiment, the controller (control unit) 32 is provided in the document feeder 10, but may be provided in the image forming apparatus. In this case, the controller that controls the image forming apparatus can also be used, so that a new controller is not required and the cost can be reduced.

  In the above-described embodiment, the document feeding device has been described as an example of the paper feeding device. However, a manual feeding device that sequentially feeds sheet-like paper to the image forming unit in order to form an image from the side of the image forming device, The present invention is also applicable to an insert device that inserts insert paper such as a front cover and back paper (cover paper) and identification slip (insert paper) used at the time of binding between normal papers carried from the image forming apparatus. be able to.

  The present invention can be used for a paper feeding device such as a document feeding device, a manual feeding device, or an insert device. The paper feeding device is an image forming device such as a copying machine, a facsimile, a printer, a scanner, or the like. Can be mounted on a multifunction machine.

FIG. 3 is a cross-sectional view illustrating an example of the document feeder according to the present invention in a state where a first tray portion is in an initial position. 3 is a block diagram illustrating an example of a control system of the document feeder according to the present invention. FIG. FIG. 3 is a cross-sectional view illustrating an example of a document feeding device according to the present invention in a state where a first tray portion is at a maximum raised position. FIG. 3 is a diagram schematically showing a state in which a small amount (less than the maximum stacking amount) of originals is set in the original feeding device of the present invention. FIG. 3 is a diagram schematically illustrating a state in which a large amount of documents (maximum stacking amount or more) is set on the document feeding device of the present invention.

Explanation of symbols

10 Document feeder (paper feeder)
11 Document feed tray (paper stacking unit)
12 Document feeding mechanism (paper feeding mechanism)
21 Device housing 24 Tray drive mechanism (drive mechanism)
31 Document set detection sensor (paper stacking detection means)
33 Document position detection sensor (paper position detection means)
32 controller (control means)

Claims (8)

A paper stacking unit on which paper is loaded;
A sheet feeding mechanism for feeding sheets one by one from the sheet stacking unit in a predetermined conveyance direction;
An apparatus housing that supports the paper stacking unit so as to be movable in the vertical direction;
A drive mechanism for moving the paper stacking unit in the vertical direction;
A paper stacking detecting means for detecting the stacking of paper on the paper stacking unit;
A paper position detecting means for detecting that the uppermost paper is positioned at a paper feedable position when the paper stacking unit is moved upward;
A paper feeding unit comprising: a control unit that determines that the stacking amount is exceeded when the paper stacking detection unit and the paper position detection unit are in a detection state before the paper stacking unit moves upward. apparatus.   2. The paper feeding apparatus according to claim 1, wherein the control unit prohibits the operation of the paper feeding mechanism and the driving mechanism when it is determined that the stacking amount is exceeded.   3. The paper feeding apparatus according to claim 1, wherein the control unit outputs a warning when it is determined that the load is excessive.   The paper feeding apparatus according to claim 3, further comprising a light emitting unit serving as an output destination of the warning.   4. The paper feeding apparatus according to claim 3, wherein the warning is output to a display unit of a connected image forming apparatus.   6. The document feeding device according to claim 1, wherein the paper feeding device is a document feeding device for feeding a document.   An image forming apparatus comprising the paper feeding device according to claim 1. A paper stacking unit on which paper is loaded;
A sheet feeding mechanism for feeding sheets one by one from the sheet stacking unit in a predetermined conveyance direction;
An apparatus housing that supports the paper stacking unit so as to be movable in the vertical direction;
A drive mechanism for moving the paper stacking unit in the vertical direction;
A paper stacking detecting means for detecting the stacking of paper on the paper stacking unit;
A paper feeding device having a paper position detecting means for detecting that the uppermost paper is positioned at a paper feeding enabled position when the paper stacking unit is moved upward;
An image forming apparatus comprising: a control unit that determines that the stacking amount is exceeded when the sheet stacking detection unit and the sheet position detection unit are in a detection state before the sheet stacking unit moves upward. .

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