JP2007320670A - Document feeder and image reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a document feeder of an image reader having an elevating/lowering document tray and capable of avoiding any careless delay of the time before a document can be fed while ensuring the easy take-out of the document by the elevating/lowering operation of the document tray. <P>SOLUTION: The document feeder comprises an elevating/lowering document tray with a document placed thereon, a discharge tray which is arranged below the document tray to discharge the document fed to the image reading position from the document tray, and a human body detection sensor for detecting a human body above a peripheral edge of the discharge tray. When the human body detection sensor detects the human body after a document set detection sensor detects no document by the feed from the document tray, the document tray is elevated from the feed position. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a document feeding device that feeds a document from a document tray to an image reading position, and an image reading device including the document feeding device.

  In image reading devices such as copiers, scanners, facsimiles, and multi-function peripherals, originals that are automatically fed one by one to the image reading position, one by one, in order to read images of multiple originals at high speed A feeding device is used. The document that has passed through the image reading position is discharged to a discharge tray provided below the document tray. The user only needs to take out the original from the discharge tray after all the originals are discharged to the discharge tray.

Patent Document 1 points out that if the distance between the document feed tray and the document discharge tray is narrow, the document cannot be easily taken out from the document discharge tray. In order to solve this problem, Patent Document 1 supports a document feed tray so that the document feed tray can be moved up and down, and when all the documents loaded on the document feed tray are fed, the document is fed to the retreat position above the document tray. A document feeder that raises the tray is described. When a document is taken out from the document discharge tray and the discharged document detection sensor no longer detects the document, the document feed tray is lowered to the home position.
JP 2006-16093 A

  Even when the original is placed on the original tray in multiple batches and read the image, it is better to take out all the originals at the same time than when taking out from the output tray, rather than taking out each time the reading is completed. Convenient. In such a case, it is useless to raise the document tray to the retracted position every time reading is completed.

  When the document tray is raised to the retracted position, the time until the document tray is lowered to the home position increases. For this reason, it takes time to feed the original for the next reading.

  The document feeding device provided by the present invention includes a document tray that can be raised and lowered to place a document, a drive mechanism that raises and lowers the document tray, a document set detection sensor that detects a document on the document tray, and an image from the document tray. A document transport mechanism that feeds a document to the reading position, a discharge tray that is disposed below the document tray and discharges the document fed from the document tray to the image reading position, and a human body above the peripheral edge of the discharge tray. A human body detection sensor for detecting, and a controller that raises the document tray from the feeding position when the human body detection sensor detects a human body after the document set detection sensor no longer detects the document due to feeding from the document tray. .

  The document feeder may further include a discharged document detection sensor that detects a document on the discharge tray. In that case, when the discharged document detection sensor detects the document after the document set detection sensor no longer detects the document due to feeding from the document tray, the control unit detects the human body. The document tray can be raised from the feeding position.

  The control unit may lower the raised document tray to the initial position when the discharged document detection sensor does not detect the document discharged to the discharge tray and the human body detection sensor does not detect the human body.

  The document feeder may further include a passing document detection sensor that detects a document that passes through the discharge unit to the discharge tray. In this case, the control unit can perform control so as not to move the document tray unless the passing document detection sensor detects that all the documents placed on the document tray have passed through the discharge unit.

  According to another aspect of the present invention, it is possible to provide an image reading device including the above-described document feeding device and an image reading unit that reads an image of the document fed by the document feeding device.

  In the present invention, only when the human body detection sensor detects the human body on the upper surface of the peripheral edge of the discharge tray, the document tray that can be raised and lowered is raised from the feeding position so that the user can easily remove the document tray from the discharge tray. Although the user is not trying to take out the original from the tray, it is possible to avoid unnecessary delay in raising the original tray from the feeding position and feeding the next original.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In this embodiment, the present invention is embodied as a document feeder provided in a digital copying machine.

  FIG. 1 is a diagram showing an example of the overall configuration of a digital copying machine according to the present embodiment. The copying machine 101 includes an image reading unit 102 and an image forming unit 103. The image reading unit 102 reads an image of a document and generates digital data of the image. The image reading unit 102 has a document table 104 made of a transparent plate such as contact glass on the upper surface of the casing. The document can be placed on the document table 104. A scanning optical system 105 is disposed below the document table 104. The scanning optical system 105 includes a first carriage 106, a second carriage 107, and a condenser lens 108. The first carriage 106 is provided with a linear light source 109 and a mirror 110, and the second carriage 107 is provided with mirrors 111 and 112. A light source 109 illuminates the document. The mirrors 110, 111, and 112 guide reflected light from the original to the lens 108, and the lens 108 forms an optical image on the light receiving surface of the line image sensor 113. In the scanning optical system 105, the first carriage 106 and the second carriage 107 are provided so as to be able to reciprocate in the sub-scanning direction 114. By moving the first carriage 106 and the second carriage 107 in the sub-scanning direction 114, the image of the document placed on the document table 104 can be read by the image sensor 113. The image sensor 113 generates document image data from the light image incident on the light receiving surface.

  The image forming unit 103 prints image data obtained by the image reading unit 102 or image data received from an external device on a sheet. The image forming unit 103 is provided with a photosensitive drum 115. The photosensitive drum 115 rotates in the arrow direction 116 at a constant speed. Around the photosensitive drum 115, a charger 117, an exposure device 118, a developing device 119, a transfer device 120, and a cleaning unit 121 are arranged in this order from the upstream side in the rotation direction. The charger 117 uniformly charges the surface of the photosensitive drum 115. The exposure device 118 irradiates the uniformly charged surface of the photosensitive drum 115 with light according to the image data to form an electrostatic latent image on the photosensitive drum 115. The developing device 119 forms a toner image on the photosensitive drum 115 by attaching toner to the electrostatic latent image. The transfer device 120 transfers the toner image on the photosensitive drum 115 to a sheet. The cleaning unit 121 cleans the surface of the photosensitive drum 115 by removing waste toner remaining on the surface of the photosensitive drum 115 from the photosensitive drum 115 after the transfer. These processes are performed in a series as the photosensitive drum 115 rotates.

  The image forming unit 103 feeds paper from the manual feed tray 122 and the paper feed cassette 123 to the transfer unit between the photosensitive drum 115 and the transfer device 120. Various sizes of paper can be placed or stored in the manual feed tray 122 or each paper feed cassette. The image forming unit 103 selects a sheet specified by the user or a sheet corresponding to the automatically detected document size, and draws the selected sheet from the manual feed tray 122 or the cassette 123 by the feeding roller 124. The drawn paper is sent to the transfer section by the transport roller 125 and the registration roller 126. The sheet on which the toner image is transferred is conveyed to the fixing device 127. The fixing device 127 includes a fixing roller 128 and a pressure roller 129, and fixes the toner image on the paper by heat and pressing force. The image forming unit 103 discharges the sheet that has passed through the fixing device 127 to the discharge tray 130.

  In such a copying machine 101, a document feeder 131 is attached to the upper side of the image reading unit 102 so as to be opened and closed. The document feeder 131 includes a document tray 132, a conveyance path 133, and a discharge tray 134. The user places a document on the document table 104 or sets the document on the document feeder 131. The document feeder 131 feeds documents set on the document tray 132 to the transport path 133 one by one by the document transport mechanism. There is an image reading position 135 on the conveyance path 133. On the upper surface of the casing of the image reading unit 102, not only the document table 104 but also a reading glass 136 for the image reading position 135 is provided. When reading an image of a document set on the document feeder 131, the image reading unit 102 temporarily fixes the first carriage 106 and the second carriage 107 to the image reading position 135. When the document passes through the image reading position 135, the document is illuminated through the reading glass 136 to read the image of the document. The document that has passed the image reading position 135 is discharged to a discharge tray 134.

  FIG. 2 is a cross-sectional view showing in more detail an example of the mechanical configuration of the document feeder according to the present embodiment. The document transport mechanism of the document feeder 131 includes a pickup roller 201, a feeding belt 202, and a separation roller 203 for separating the documents one by one from the document bundle placed on the document tray 132. The pickup roller 201 is pressed against the tip of the uppermost surface of the document bundle. By driving the pickup roller 201 in this state, the original is pulled out from the original bundle. Even if there are two or more drawn documents, the first document is separated from the documents by the feeding belt 202 and the separation roller 203 and conveyed to the downstream side of the conveying path 133. A registration roller 204 and a conveyance roller 205 are provided downstream thereof. The timing at which the registration roller 204 conveys to the image reading position 135 is adjusted, and the conveyance roller 205 conveys the document to the image reading position 135. An image on one side of the document is read at the image reading position 135. In the document feeder 131, a document reading unit 206 that employs a contact optical system is disposed downstream of the image reading position 135. When reading images on both sides of an original, the original reading unit 206 reads the remaining side images. The document that has passed through the document reading unit 206 is discharged from the discharge unit to the discharge tray 134 by a discharge roller 207. After all the images of the document placed on the document tray 132 have been read, the user can insert his / her hand between the document tray 132 and the discharge tray 134 to collect the documents from the discharge tray 134. it can.

  In this document feeder 131, the document tray 132 includes a downstream tray 209 disposed on the downstream side in the document transport direction 208 and an upstream tray 210 disposed on the upstream side in the document transport direction 208.

  A pair of document cursors 211 is arranged on the upper surface of the downstream tray 209. The document cursor 211 is attached such that it can reciprocate in the document width direction. By centering the document placed between the document cursors 211 with the document cursor 211, the center of the document in the width direction can be aligned with the machine.

  The upstream tray 210 is swingably connected to the upstream end in the document conveyance direction 208 on the downstream side 209. When the user takes out the document from the discharge tray 134, the upper space of the discharge tray 134 can be expanded by lifting the upstream tray 210 as necessary.

  The document tray 132 is supported by the lifting mechanism 212 on both sides of the downstream tray 209 so as to be lifted and lowered. The lifting mechanism 212 includes a rack 213 and a pinion 214. By driving the pinion 214 with a motor, the document tray 132 moves up and down along the long side direction 215 of the rack 213. For example, when a document is placed on the document tray 132, the document tray 132 is raised from the initial position (home position) and the upper surface of the document bundle is pressed against the pickup roller 201. Whether or not a document is placed on the document tray 132 can be detected using a document set detection sensor 216 such as an optical sensor. Whether or not the upper surface of the document bundle has reached the feeding position pressed against the pickup roller 201 is detected using an upper limit position detection switch 217. This detection signal is monitored while the originals placed on the original tray 132 are fed one by one. When the document is fed and the upper surface of the bundle of documents becomes lower than the feeding position, the document tray 132 is raised until the upper limit position detection switch 217 detects again. In this way, during document feeding, the upper surface of the document bundle is adjusted to the feeding position.

  FIG. 3 is a diagram showing the document feeder in a state where the document tray is at the home position. When reading of the document image is completed and the document is taken out from the discharge tray 134, the document tray 132 is lowered to the home position by driving the pinion 214. A lower limit position detection sensor 301 is arranged at the home position. When the lower limit position detection sensor 301 detects the document tray 132, the motor stops driving.

  FIG. 4 is a diagram showing the document feeder in a state where the document tray is in the upper retracted position. When all the documents placed on the document tray 132 are fed, the distance between the document tray 132 and the discharge tray 134 is wider than when the document tray 132 is almost at the feeding position and at the home position. If this interval is wide, the user can easily take out the original from the discharge tray 134.

  In order to further widen the interval, the document feeder 131 can raise the document tray 132 to the upper retreat position higher than the feeding position. For example, using the document set detection sensor 216, the passing document detection sensor 401, and the discharged document detection sensor 402, it is determined whether all the documents placed on the document tray 132 are discharged to the discharge tray 134, and all the documents are detected. If the document is discharged, the document tray 132 is raised from the feeding position to the upper retracted position. If the passing document detection sensor 401 detects the passage of the last document after the document set detection sensor 216 is turned off, and the discharged document detection sensor 402 detects the document on the discharge tray 134, the pinion 214. Is driven for a predetermined time to raise the document tray 132.

  However, when the document tray 132 is raised to the upper retracted position, the time required to lower the document tray 132 to the home position is longer than when the document tray 132 is lowered from the feeding position. In that case, the time required until the next feeding is increased.

  Therefore, the document feeder 131 includes a human body detection sensor 403 that detects a human body above the peripheral edge of the discharge tray 134. In this embodiment, an optical sensor is disposed as the human body detection sensor 401 on the upper surface of the peripheral edge of the discharge tray 134 on the upstream side in the document conveying direction 208. After the document feeder 131 determines that all the documents have been discharged, when the human body detection sensor 401 detects the user's hand that has been inserted above the discharge tray 139, the document tray 132 is moved to the upper retracted position. Raise.

  As a result, the document tray 132 rises to the upper retracted position only when the user actually takes out the document from the discharge tray 134. When an original is placed on the original tray in multiple batches and an image is read, if the user does not intend to take out the original from the discharge tray 134 at the end of each reading, the original tray 132 is moved upward. It does not rise unnecessarily to the retracted position. For this reason, it is possible to shorten the time until the document for the second and subsequent readings can be fed, compared to when the document tray 132 is raised to the upper retracted position every time reading is completed.

  FIG. 5 is a diagram illustrating a configuration example of a control system of the document feeder. A dedicated circuit or a general-purpose arithmetic circuit can be used for the control unit 501 of the document feeder. In this embodiment, a general-purpose circuit is used, and the control unit 501 includes a CPU 502, a ROM 503, and the like. The ROM 503 stores a control program, and the CPU 502 controls the document feeder 131 in accordance with an instruction of the control program.

  Various drive motors, sensors, and switches are connected to the control unit 501. In this embodiment, the control unit 501 is connected to a lift motor 504, a paper feed motor 505, a registration motor 506, a transport motor 507, and a paper discharge motor 508, and controls each motor independently. The lift motor 504 drives the lifting mechanism, and the paper feed motor 505 drives the pickup roller. The registration motor 506 drives the registration roller, and the transport motor 507 and the paper discharge motor 508 drive the transport roller and the discharge roller, respectively.

  The control unit 501 is connected to sensors and switches such as a document set detection sensor 216, an upper limit position detection switch 217, a lower limit position detection sensor 301, a passing document detection sensor 401, a discharged document detection sensor 402, and a human body detection sensor 403. . Further, the control unit 501 is also connected to the operation panel 510 via the control unit 509 of the copying machine main body. The operation panel 510 has a start key, and the user instructs the copying machine to start copying by operating the star key.

  FIG. 6 is a flowchart for explaining an example of the control procedure of the document feeder. The CPU of the control unit executes these procedures in accordance with instructions from the control program. First, the CPU monitors whether the output of the document set detection sensor is on (procedure 601). When a document is placed on the document tray and the output of the document set detection sensor is turned on, the CPU determines whether the upper limit position detection switch is on or off (step 602). The lift motor is driven until it is turned on (procedure 603). As a result, the upper surface of the original bundle on the original tray comes into contact with the pickup roller, and the original can be fed. When the upper limit position detection switch is turned on and it is determined that the upper surface of the document bundle is at the feeding position, the CPU monitors input on the operation panel and determines whether or not the user has pressed the start key (step 604).

  When the user presses the start key, the CPU conveys the document placed on the document tray (procedure 605). While the document is being conveyed, the CPU monitors whether the upper limit position detection switch is on (step 606). When the height of the document bundle is lowered by feeding the document and the upper limit position detection switch is turned off, the CPU drives the lift motor until the upper limit position detection switch is turned on (step 607). When the upper limit position detection switch is on and the document is at the feeding position, the CPU monitors whether the document set detection sensor is on or off (step 608). If the document set detection sensor remains on because the document remains on the document tray, steps 606 and 607 are repeated. On the other hand, when all the documents on the document tray are fed and the document set detection sensor is turned off, the CPU monitors whether or not the passing document detection sensor is turned off (step 609). When the passing document detection sensor is turned off and it is determined that the last document has passed, the CPU checks whether or not the discharged document detection sensor is turned on (step 610).

  If the discharged document detection sensor is off, the CPU checks whether the human body detection sensor is off (step 611). If the user does not reach between the document tray and the discharge tray and the human body detection sensor is off, the CPU checks the output of the lower limit position detection sensor (step 612). If the lower limit position detection sensor is off, the lift motor is operated in the reverse direction until it is turned on (procedure 613). As a result, the document tray is lowered from the feeding position to the home position.

  On the other hand, if the discharged document detection sensor is on in step 610, the CPU checks whether the human body detection sensor is on (step 614). When the human body detection sensor is on, the CPU operates the lift motor in the forward direction for a predetermined time (procedure 615). As a result, the document tray rises from the feeding position to the upper retracted position, and the user can easily take out the document from between the document tray and the discharge tray. When the lift motor is operated for a predetermined time, the CPU monitors the output of the discharged document detection sensor (procedure 616) and confirms whether or not the document is taken out from the discharge tray. When the user removes a document from the discharge tray and the discharged document detection sensor is turned off, the CPU executes steps 611 to 613. As a result, the document tray is lowered from the upper retracted position to the home position.

  If the human body detection sensor is off in step 614, the user is not trying to take out the document on the discharge tray. In this case, the CPU executes steps 611 to 613 without raising the document tray from the feeding position. As a result, the document tray is lowered from the feeding position to the home position, and the user can place another document on the document tray. The time until the document tray returns to the home position is shorter than when the document tray is lowered from the upper retracted position to the home position.

  If the user places another document on the document tray, the CPU executes the procedure after step 601 again while the previous document remains on the discharge tray. In this way, when placing a document in a plurality of times, this document feeding device moves the document tray upward every time reading of each document is completed unless the user tries to remove the document from each discharge tray. Do not raise to the retracted position.

  Further, in the control procedure described above, the document tray is not moved until it is detected that all the documents have passed through the discharge unit. For this reason, even if the user extends his hand between the document tray and the discharge tray while reading the image of the document, the document tray does not descend.

  The control program as described above can be provided to a third party using a computer-readable medium. For example, a program command is expressed by an electric signal, an optical signal, a magnetic signal, etc., and the signal is placed on a carrier wave and transmitted, so that the program is provided on a transmission medium such as a coaxial cable, copper wire, or optical fiber. Can do. The control program may be recorded on a computer-readable recording medium. Computer-readable recording media include optical media such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-R, and DVD-RW, magnetic media such as flexible disks, A semiconductor memory such as a flash memory or a RAM can be used.

  In the above document feeder, when the human body detection sensor detects a human body regardless of the size of the document, the document tray is raised from the feeding position. However, when the document size is equal to or smaller than the predetermined size, the human body detection sensor May be raised from the feeding position. The document size can be specified, for example, by detecting the width between a pair of document cursors. If the document size is larger than the predetermined size, the discharged document edge approaches the peripheral edge of the discharge tray, so that it is easier to take out the document from the discharge tray than a document of a predetermined size or less. In such a case, by avoiding raising the document tray from the feeding position, it is possible to shorten the time until the document can be fed as much as possible while ensuring the ease of taking out the document.

  In the above document feeder, the human body detection sensor is disposed on the upper surface of the peripheral edge of the discharge tray on the upstream side in the document transport direction. However, the present invention is not limited to this. For example, in order to make it easy to take out the document, a notch is provided in the document tray, and when the discharge tray has an area where the document tray does not overlap with the notch, the human body detection sensor is arranged in that area. It may be.

  Further, the present invention can also be applied to an image reading apparatus other than a digital copying machine such as a printer, a facsimile machine, and a multifunction machine and its original feeding apparatus.

  The embodiments described above do not limit the technical scope of the present invention, and various modifications and applications other than those already described are possible within the scope of the present invention.

  According to the document feeding device and the image reading device of the present invention, the document tray is raised from the feeding position only when the human body detection sensor detects the human body on the upper surface of the peripheral edge of the discharge tray, and the user can copy the document from the discharge tray. This makes it easy to remove the tray and avoids unnecessary delay in reading the next document by raising the document tray from the feeding position when the user is not trying to remove the document from the discharge tray. This is useful for various devices such as printers, facsimiles, and multifunction machines.

1 is a diagram illustrating an example of an overall configuration of a digital copying machine according to an embodiment. FIG. 3 is a diagram illustrating an example of a more specific configuration of a document feeding device according to the present embodiment. FIG. 3 is a diagram illustrating a document feeding device in a state where a document tray is in an upward retracted position. FIG. 6 is another diagram for explaining an operation state of the document feeder. FIG. 3 is a diagram illustrating a configuration example of a control system of a document feeder. 6 is a flowchart for explaining an example of a control procedure of the document feeder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Copy machine 102 Image reading part 103 Image forming part 131 Document feeder 132 Document tray 133 Conveying path 134 Ejection tray 212 Lifting mechanism 216 Document set detection sensor 217 Upper limit position detection switch 301 Lower limit position detection sensor 401 Passing document detection switch 402 Ejection Document detection switch 403 Human body detection switch 501 Control unit

Claims (5)

An elevating document tray for placing documents;
A drive mechanism for raising and lowering the document tray;
A document set detection sensor for detecting a document on the document tray;
A document transport mechanism for feeding documents from the document tray to the image reading position;
A discharge tray that is disposed below the document tray and from which the document fed from the document tray to the image reading position is discharged;
A human body detection sensor for detecting a human body above the periphery of the discharge tray;
A document feeding device comprising: control means for raising the document tray from a feeding position when the human body detection sensor detects a human body after the document set detection sensor no longer detects the document due to feeding from the document tray. A discharge document detection sensor for detecting a document on the discharge tray;
If the control unit detects that the discharged document detection sensor detects a document after the document set detection sensor no longer detects the document due to feeding from the document tray, the document tray is detected when the human body detection sensor detects the human body. The document feeder according to claim 1, wherein the document feeder is raised from the feeding position.   3. The control unit according to claim 2, wherein the control unit lowers the raised document tray to an initial position when the discharged document detection sensor does not detect the document discharged to the discharge tray and the human body detection sensor does not detect the human body. Document feeder. A passage document detection sensor for detecting a document passing through the discharge portion to the discharge tray;
3. The document feeding apparatus according to claim 2, wherein the control means does not move the document tray unless the passing document detection sensor detects that all the documents placed on the document tray have passed through the discharge section. The document feeder according to any one of claims 1 to 4,
An image reading device comprising: an image reading unit that reads an image of a document fed by a document feeding device.

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