JP2019014581A - Sheet transport device - Google Patents

Abstract

A sheet conveying device capable of easily adding documents is provided. A sheet conveying device includes a guide plate document detection sensor 62 for detecting the presence of an object in a space above a sheet stacking surface of a document tray 41 and higher than a maximum stacking height of sheets on the document tray 41. I have. When the guide plate document detection sensor 62 detects the presence of an object while the feeding roller 43 and the sheet on the document tray 41 are in contact with each other, the feeding roller 43 and the sheet on the document tray 41 are separated from each other. Switch to standby state. [Selection] Figure 4

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet.

  2. Description of the Related Art In recent years, an image reading apparatus equipped with an automatic document feeder (ADF: Auto Document Feeder) has become widespread due to a request for quickly reading an image of a plurality of originals. In general, the ADF is provided with a document presence / absence detection sensor for detecting the presence / absence of a document on a document tray on which a user stacks the document. Detected. Conventionally, the following techniques have been proposed in order to cope with high-speed reading of ADF images without deteriorating the user's ability to load a document by using this document loading as a trigger.

  For example, in Japanese Patent Laid-Open No. 2004-260688, after the document set is detected on the document tray of the ADF, the operation of the document guide plate or the document is monitored. The technique of performing is proposed. Japanese Patent Application Laid-Open No. 2004-228561 proposes a technique for detecting that a document is stacked on a document tray and raising the document tray.

JP 2013-237536 A Japanese Patent No. 3747986

  However, for example, the technique described in Patent Document 1 has a problem in that it is difficult to add a document when a user attempts to add and stack documents for a predetermined time after setting a document guide plate. The technique described in Patent Document 2 also has a problem that it is difficult to add and stack documents after the document tray is raised.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet conveying apparatus that can easily add documents.

  According to the sheet conveying apparatus of the present invention, a sheet stacking unit on which sheets are stacked, a sheet presence / absence detecting unit for detecting whether or not a sheet is stacked on the sheet stacking unit, and the sheet stacking unit are stacked. A sheet feeding unit that feeds the sheet, a feedable state in which the sheet feeding unit and the sheet stacked on the sheet stacking unit are in contact, and a stacking on the sheet feeding unit and the sheet stacking unit Switching means that can be switched to a standby state in which the separated sheets are separated from each other, and an object in a space above the sheet stacking surface of the sheet stacking unit and higher than the maximum stacking height of the sheets in the sheet stacking unit Based on the fact that the sheet stacking detection means for detecting the presence of the sheet and the sheet presence / absence detection means detected a sheet, the switching means is controlled to be in the feeding enabled state, A control unit that controls the switching unit to switch from the feeding enabled state to the standby state based on the fact that the sheet stacking detecting unit detects the presence of an object in the feeding enabled state. It is characterized by that.

  According to the present invention, the sheet feeding apparatus includes a sheet stacking detection unit that detects the presence of an object at a position higher than the maximum stacking height of sheets in the sheet stacking unit. When the sheet stacking detection unit detects the presence of an object in the feedable state, the switching unit is controlled to switch from the feedable state to the standby state. For this reason, it is possible to detect the document adding operation by the sheet stacking detection means. Further, since the sheet feeding unit and the sheets stacked on the sheet stacking unit are in a standby state in which the sheets are separated based on the detection of the document adding operation, the sheets can be easily added.

1A is a schematic diagram of an image forming apparatus according to a first embodiment, and FIG. 1B is a schematic diagram illustrating a configuration of an image forming unit. FIG. 2 is a block diagram of the image forming apparatus in FIG. 1. 1 is a perspective view of an image reading apparatus according to a first embodiment. (A) The figure which shows the state where the original was loaded on the original tray of ADF, (b) The figure which shows the state where the pickup roller descended from the state of FIG. 4 (a), (c) The addition of the original to the original tray The figure which shows the state to be called. FIG. 3 is a flowchart showing control at the time of document addition in the first embodiment. (A) A diagram showing a state in which a plurality of documents are stacked on a document tray. (B) From the state of FIG. 6A, the feeding roller is lowered by the same amount as that of a single stacked document. The figure which shows a state. (A) The figure which shows the image reading apparatus which concerns on 2nd Embodiment, (b) The figure which shows the state which the document tray raised. FIG. 6 is a block diagram of an image forming apparatus according to a second embodiment. FIG. 9 is a flowchart showing control at the time of document addition in the second embodiment. FIG. 3 is a schematic diagram illustrating the image reading apparatus in a full state. FIG. 3 is a perspective view of an image reading apparatus provided with a plurality of guide plate document detection sensors.

<First Embodiment>
[overall structure]
Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a printer 1 as an image forming apparatus according to the first embodiment. As shown in FIG. 1, the printer 1 includes an apparatus main body 2 and an image reading device 3 provided on the upper part of the apparatus main body 2, and image forming means for forming an image on a sheet inside the apparatus main body 2. An image forming unit 10 and a control unit 20 are provided.

  As shown in FIG. 1B, the image forming unit 10 includes an electrophotographic image forming unit PU and a fixing device 17. In this image forming unit PU, when the start of the image forming operation is instructed, the photosensitive drum 11 as a photosensitive member rotates, and the drum surface is uniformly charged by the charging device 12. Then, the exposure device 13 modulates and outputs a laser beam based on the image data transmitted from the image reading device 3 or an external computer, and scans the surface of the photosensitive drum 11 to form an electrostatic latent image. This electrostatic latent image is visualized (developed) with toner supplied from the developing device 14 and becomes a toner image.

  In parallel with such an image forming operation, a feeding operation for feeding sheets stacked on a cassette or a manual feed tray (not shown) toward the image forming unit 10 is executed. The fed sheet is conveyed in accordance with the progress of the image forming operation by the image forming unit PU. The toner image carried on the photosensitive drum 11 is transferred onto the sheet by the transfer roller 15. The toner remaining on the photosensitive drum 11 after the toner image transfer is collected by the cleaning device 16. The sheet on which the unfixed toner image is transferred is transferred to the fixing device 17, and is sandwiched between the roller pair and heated and pressed. The sheet on which the image is fixed by melting and fixing the toner to the sheet is discharged by a discharge unit such as a discharge roller pair.

[Image reading device]
Next, the configuration of the image reading device 3 will be described in detail. In the present embodiment, the sheet is not only plain paper but also special paper such as coated paper, recording material having a special shape such as envelope or index paper, and plastic film or cloth for overhead projectors. Is included. The document is also an example of a sheet, and the document may be a blank sheet or an image may be formed on one side or both sides.

  As shown in FIG. 1A, the image reading device 3 includes an image reading unit 5 that reads an image of a document, and an automatic document conveying device (sheet conveying device that can be opened and closed with respect to the image reading unit 5). (Hereinafter simply referred to as ADF) 4. The image reading unit 5 includes an original table glass 70 on which an original is placed, and an optical scanner unit 71 that is movable in the sub-scanning direction (the arrow X direction in FIG. 1A). The document can be read by two types of methods called flow reading. In the fixed reading, the image reading unit 5 scans the original set on the original platen glass 70 by scanning the optical scanner unit 71 at a constant speed in the sub-scanning direction, so that the image information recorded on the original is 1 Read line by line. In the flow reading, the optical scanner unit 71 is moved so as to come to the center position of the read roller 49 of the ADF 4 so that the original on the original tray 41 conveyed by the ADF 4 is optically read.

  The ADF 4 regulates the document tray 41 on which the document bundle S composed of one or more documents is stacked, and the document bundle S protrudes from the document tray 41 and advances downstream before the document conveyance starts. A separation pad 45 and a separation roller 44, and a feeding roller 43 are provided. The document tray 41 as a sheet stacking unit for stacking sheets is provided with an optical document presence / absence detection sensor 63 so that the presence / absence of a document on the document tray 41 can be determined. Further, the document tray 41 is provided with a pair of document guide plates 42 for aligning the positions of documents placed on the document tray 41 in the width direction (direction perpendicular to the document feeding direction). In the present embodiment, the document presence / absence detection sensor 63 constitutes sheet presence / absence detection means for detecting whether or not a sheet is stacked on the sheet stacking unit. Further, the document guide plate 42 constitutes a restricting portion that restricts the position of the sheet stacked on the sheet stacking portion in the width direction orthogonal to the sheet conveying direction. The feed roller 43 is configured to be movable up and down via an arm. When the feed roller 43 is lowered from a retracted position positioned above, the feed roller 43 and the uppermost document (uppermost) document stack S stacked on the document tray 41 It is configured to abut and feed. In the present exemplary embodiment, the feeding roller 43 constitutes a sheet feeding unit that feeds the sheets stacked on the sheet stacking unit. The document fed by the feeding roller 43 is separated from the separation roller 44. The sheets are separated and fed one by one by the action of the separation pad 45.

  The document separated by the separation roller 44 and the separation pad 45 is conveyed to the registration roller pair 47 by the drawing roller 46, and the document is abutted against the registration roller pair 47. As a result, a loop-like deflection is formed on the document, and skew feeding during the conveyance of the document is corrected. On the downstream side of the registration roller pair 47, a conveyance path is provided for feeding the original document that has passed through the registration roller pair 47 and conveying it to the reading glass 57. The original document sent to this conveyance path is a reading upstream roller. 48 is conveyed to the image reading position. At the image reading position, the surface of the document is irradiated by the LEDs 74a and 74b, and the reflected light is guided to the image reading sensor 72 while being bent by the plurality of mirrors 73a to 73c, and the surface image of the document is read line by line.

  A reading downstream roller 50 is provided downstream of the read roller 49 in the document conveying direction. When the document conveyed by the reading downstream roller 50 reads only the surface image of the document, the sheet discharge tray 56 discharges the document. 51 is discharged. A paper discharge sensor 68 is provided on the upstream side of the paper discharge roller 56 so as to detect a discharged document. When there are a plurality of documents on the document tray 41, the image reading device 3 repeats the above-described processing until the reading of the final document and the discharge to the discharge tray 51 are completed.

  On the other hand, when the back side image of the document is also read, the front image is read, and after the trailing edge of the document passes through the paper discharge sensor 68, the document is stopped before passing through the paper discharge roller 56. Then, by rotating the paper discharge roller 56 in the reverse direction, the original is conveyed toward the registration roller pair 47 via the double-sided conveyance path 58, and the original is conveyed in the same manner as when reading the front surface image. Can be read.

[Control Unit of Image Forming Apparatus]
FIG. 2 is a block diagram illustrating a configuration of the control unit of the printer 1. As shown in FIG. 2, the printer 1 includes different control units 20 and 106 for the apparatus main body 2 and the image reading apparatus 3, respectively. Each of these two control units 20 and 106 includes CPUs 80 and 100 as arithmetic means, ROMs (read only memories) 81 and 101 and RAMs (random access memories) 82 and 102 as storage means. . The ROMs 81 and 101 store various control programs including a feeding program described later, and the RAMs 82 and 102 store input data and work data when the CPUs 81 and 101 execute the various programs. .

  The CPU 80 is connected to a separation motor 55 and a reading motor 54 in order to realize a document conveying function. The separation motor 55 includes a feeding roller 43, a separation roller 44, a drawing roller 46, and a registration roller pair. 47 is configured to be rotationally driven. The reading motor 54 is configured to drive the reading upstream roller 48, the reading roller 49, the reading downstream roller 50, and the paper discharge roller 56. Further, among these rollers, for example, a roller such as a feeding roller 43 is configured to transmit power from the separation motor 55 and the reading motor 54 via the clutch 52, and the CPU 80 includes the clutch 52 and the clutch. A solenoid 53 for driving the valve 52 is also connected. The CPU 80 rotates the separation motor 55 in the forward direction to rotate the feeding roller 43, the separation roller 44, the drawing roller 46, and the registration roller pair 47 in a direction in which the document is fed downstream. Further, by rotating the separation motor 55 in the reverse direction, the feeding roller 43 can be lifted upward. In the present embodiment, the separation motor 55 constitutes lifting / lowering means for moving the feeding roller 43 as sheet feeding means up and down. Further, by this lifting / lowering means, the feedable state in which the feed roller 43 and the sheet (document) stacked on the document tray 41 contact each other, and the feed roller 43 and the sheet stacked on the document tray 41 are separated from each other. Switching means that can switch between the standby state and the standby state is configured.

  Further, the CPU 80 includes a document presence / absence detection sensor 63 that detects documents stacked on the document tray 41, a post-separation sensor 64 that detects an end portion of the document on the sheet conveyance path, a pull-out sensor 65, a registration sensor 66, a lead sensor 67, a discharge sensor 67. A paper sensor 68 is connected. The separation motor 55 and the reading motor 54 are pulse motors, and the CPU 80 can manage the rotation speed of each motor by controlling the number of drive pulses.

  The CPU 80 is connected to LEDs 74 a and 74 b and an image reading sensor 72 in order to realize an image reading function, and image data read by the image reading sensor 72 is sent to the image line 107 via the image processing unit 83. Directly sent to the apparatus body 2 side. Further, the vertical synchronization signal serving as the reference of the leading edge of the document image data and the horizontal synchronizing signal serving as the reference of the pixel leading edge of one line are sent to the apparatus main body 2 through the controller IF unit 108 at a timing. .

  As described above, the control unit 106 on the apparatus body 2 side exchanges data related to image reading control between the CPU 80 on the image reading apparatus side and the CPU 100 on the apparatus body side via the controller IF section (communication line) 108. Is done. The image data is communicated via the image line 107 between the image processing unit 83 and the image processing unit 103, and the data received from the image reading unit 5 is stored in the image memory 104. Further, the apparatus main body 2 is provided with an operation unit 105 that is operated by a user, and interface control with the user is performed by the CPU 100 via the operation unit 105.

[Document addition detection]
Next, a detection configuration of an operation in which the user tries to add a document will be described with reference to FIGS. First, a use case where a user adds a manuscript will be described. For example, the original tray 41 in the present embodiment can load 200 plain paper originals. Here, in order to load the originals on the original tray 41, the vertical and horizontal sides of the originals must be aligned to some extent. However, when the user attempts to align the vertical and horizontal sides of the 200 original bundles, It is heavy and takes time to align the vertical and horizontal sides. For this reason, it is conceivable that the user divides a bundle of 200 documents into 100 sheets and loads them on the document tray 41 100 by 100. In this use case, when the user sets the first 100 document bundles on the document tray 41 and then sets the remaining 100 document bundles on the document tray 41 for the second time, the document addition operation is performed. Will be carried out.

  FIG. 3 is a view of the image reading device 3 as viewed from obliquely above. When 200 sheets of the maximum number of plain papers are stacked on the document tray 41 of the ADF 4, the originals are stacked up to the upper limit line portion 42 a of the document guide plate 42. In the present embodiment, the document guide plate 42 is provided with a guide plate document detection sensor 62. The guide plate document detection sensor 62 is provided above the upper limit line portion 42 a of the document guide plate 42 with respect to the document tray 41 and at an end position on the side away from the feeding roller 43. Therefore, the guide plate document detection sensor 62 can detect that there is a document or a user's hand in the space L0 between the document guide plates 42, and can detect a user's document addition operation. It can be done. That is, the guide plate document detection sensor 62 detects the presence of an object in a space above the sheet stacking surface of the sheet stacking unit 41 and at a position higher than the maximum sheet stacking height 42a in the sheet stacking unit 41. It is a detection means.

  In the present embodiment, the guide plate document detection sensor 62 is provided on one of the pair of document guide plates 42. The other document guide plate 42 is configured to include an optical sensor (photoelectric sensor) that irradiates light and detects the presence of a document or the like by the difference in reflected light of the light. However, the present invention is not limited to this configuration, and the guide plate document detection sensor 62 may be configured by a photoelectric sensor including a light emitting unit on one of the pair of document guide plates 42 and a light receiving unit on the other. Further, for example, an ultrasonic sensor or a sensor that projects a protrusion in the space L0 and detects contact with the protrusion may be used.

  Further, in the present embodiment, there is one guide plate document detection sensor 62 and one of the document guide plates 42 is disposed at a position away from the feeding roller 43. The position is not limited to this as long as it can be detected. Further, as shown in FIG. 11, the guide plate document detection sensor 62 may be provided in a plural number instead of one. That is, in FIG. 11, four guide plate document detection sensors, guide plate document detection sensors 62a to 62d, are arranged side by side in the sheet feeding direction, and are in spaces L1 to L4 between the document guide plates 42, respectively. It can detect the presence of manuscripts and user's hands. In this case, when one or more of the guide plate document detection sensors 62a to 62d detect an object and output an ON signal, it is determined that the adding operation is being performed. Even when a plurality of sensors are provided, a plurality of sensors may be arranged on one side of the document guide plate 42 as shown in FIG. Good.

  FIG. 4C is a diagram illustrating a state in which the user tries to add a document. When the user tries to add the document S1 onto the document tray 41 with the document S0 on the document tray 41, the document S1 is at the position where the guide plate document detection sensor 62 is mounted as shown in FIG. Then, it passes through the space between the document guide plates 42 (L0 portion in FIG. 3). For this reason, the guide plate document detection sensor 62 is turned ON to detect the document S1, and the CPU 80 can detect the user's document addition operation based on the ON signal of the guide plate document detection sensor 62. .

  The guide plate document detection sensor 62 is a sensor for detecting that an attempt to transport a document out of specification such as a stapled document is made by the CPU 80 monitoring the ON signal of the guide plate document detection sensor 62 at the start of a job. It may be used as

[Feed control when detecting document addition]
Next, the feeding control at the time of document addition detection based on the feeding program will be described with reference to FIGS. The CPU 80 reverses the separation motor 55 and raises the feeding roller 43 as shown in FIG. 4A so that the user can easily stack the documents on the document tray 41 when the power is turned on or when the job is finished. (S101 in FIG. 5). Then, the CPU 80 confirms whether the image reading job is started in a state where the feeding roller 43 is positioned at the standby position separated from the document tray 41 (S102).

  For example, when the user operates the operation unit 105 to start an image reading operation, the CPU 100 detects this and notifies the CPU 80 of the start of an image reading job. Upon receiving the image reading job start notification, the CPU 80 determines that the job is started (YES in S102), and determines the presence / absence of documents on the document tray 41 based on the output signal of the document presence / absence detection sensor 63 (S110). If there is a document on the document tray 41 (YES in S110), the CPU 80 causes the separation motor 55 to rotate forward to lower the feeding roller 43 to the document surface (S111), and the document conveyance described above. Then, image reading is performed (S108). Then, it is confirmed whether or not the reading of the last document has been completed (S109). If the reading of the last document has been completed (YES in S109), the process ends. If reading has not been completed up to the final document (NO in S109), document conveyance and document reading are performed again (S108). By repeating this, the image reading is performed up to the final document stacked on the document tray 41.

  If there is no document on the document tray 41 in step S110 (NO in S110), the document placed on the document table glass 70 is scanned by the optical scanner unit 71 at a constant speed in the sub-scanning direction. Is read (S112).

  On the other hand, if the CPU 80 determines in step S102 that there is no job start (NO in S102), the CPU 80 monitors the presence / absence of the document by the document presence / absence detection sensor 63 and checks whether there is a document on the document tray 41 (S103). ). In this state, when the document presence / absence detection sensor 63 detects that there is no document, the CPU 80 determines that there is no document on the document tray 41 (NO in S103) and confirms the job start notification again (S102). Further, when the CPU 80 determines that there is a document on the document tray 41 in step S103 (YES in S103), the CPU 80 rotates the separation motor 55 in the normal direction, so that the feeding roller 43 as shown in FIG. Is lowered onto the original surface (S104).

  Next, the CPU 80 determines whether or not the user intends to add a document by performing the above-described document addition detection (S105). When the user is trying to add a document as shown in FIG. 4C, the document stacking operation of the user is hindered if the feeding roller 43 is lowered. Therefore, when the guide plate document detection sensor 62 detects the document addition operation (YES in S105), the CPU 80 reverses the separation motor 55 and raises the feed roller 43 as shown in FIG. 4A (S101).

  If the CPU 80 determines in step S105 that there is no additional document (NO in S105), the CPU 80 checks the presence / absence of the document by the document presence / absence detection sensor 63 again to determine the presence / absence of the document on the document tray 41 (S106). . Based on this determination, it is possible to detect whether or not the user has removed the document loaded on the document tray 41 once.

  In step S106, if there is no document on the document tray 41 (NO in S106), the CPU 80 determines that the user once removed the document stacked on the document tray 41. The CPU 80 then reverses the separation motor 55 and raises the feed roller 43 as shown in FIG. 4A in preparation for setting the document on the document tray 41 again (S101). If it is determined in step S106 that there is a document on the document tray 41 (YES in S106), the CPU 80 checks whether a job has been started (S107).

  If the CPU 80 determines in step S107 that there is no job start (NO in S107), the CPU 80 determines again whether the user is trying to add a document (S105). If the CPU 80 determines in step S107 that the job has started (YES in S107), the CPU 80 performs the document conveyance and image reading described above (S108) and ends the process. In this case, since the document feeding is started from the state where the feeding roller 43 is lowered as shown in FIG. 4B, the state of the feeding roller 43 is changed from the state where the feeding roller 43 is raised as shown in FIG. The processing can be accelerated compared to the case where the document is lowered and the document conveyance is started.

  In the present embodiment, the CPU 80 immediately lowers the feeding roller 43 when there is a document on the document tray 41, but the present invention is not limited to this. For example, it may be controlled to start time measurement by a timer when it is detected that there is a document on the document tray 41 and to lower the feeding roller 43 after a predetermined time has passed with the document being present. As a result, when the user carries out the document adding operation immediately after loading the document on the document tray 41, the feeding roller 43 can be prevented from moving up and down unnecessarily.

  Further, the time until the feeding roller 43 is lowered after the document is present on the document tray 41 may be changed depending on conditions. For example, the time from when there is a document on the document tray 41 until the first lowering of the feeding roller 43 and the second and subsequent feeding rollers 43 after the document addition is detected and the feeding roller 43 is raised. The time until the descent may be changed.

  In this embodiment, in step S104, the CPU 80 is set so as to lower the feed roller 43 until it contacts the upper surface of the original when the originals are stacked. However, the lowering amount of the feed roller 43 is set. It is not limited to this. In the present embodiment, for example, there is no way to detect that a plurality of documents are placed on the document tray 41 as shown in FIG. For this reason, the configuration of the feed roller 43 is lowered when the separation motor 55 is rotated forward, and is rotated in the conveying direction when the clutch 52 is turned on while the separation motor 55 is rotated forward. Therefore, even if the feeding roller 43 is lowered until it comes into contact with the upper surface of the original when the originals on the original tray 41 are stacked, as shown in FIG. Even if a single document is placed on the document tray 41, the uppermost document is not fed.

  However, there is no way for the CPU 80 to know the number of documents on the document tray 41, and when the separation motor 55 is rotated forward, the feed roller 43 is lowered, and the feed roller 43 is rotated only by the forward rotation of the separation motor 55. The configuration can also be considered. In this case, for example, the CPU 80 may set the set value of the lowering amount so that the feeding roller 43 is lowered by an amount contacting the upper surface of the original when the maximum number of originals is stacked. As a result, when a plurality of documents are stacked, it is possible to prevent unintentional pulling of the uppermost document.

  As another example of the setting value of the lowering amount, the first setting value of the lowering amount of the feeding roller 43 after the document is present on the document tray 41 and the document addition is detected and the feeding roller 43 is raised. The set value of the lowering amount of the feeding roller 43 after the second time may be changed. This is because the amount of documents on the document tray 41 increases with each addition, assuming that the user performs addition, until the feeding roller 43 comes into contact with the uppermost document on the document tray 41. This is because the amount of descent of is reduced.

  Further, the setting of the lowering speed of the feeding roller 43 may be changed depending on conditions. For example, when the first feeding roller 43 is lowered after the document is present on the document tray 41, and when the feeding roller 43 is lowered for the second time or more after the document addition is detected and the feeding roller 43 is raised. The speed may be changed. For example, the speed when the first feeding roller 43 descends with a large amount of descending the feeding roller 43 may be set faster. As another example, a lowering speed when the feeding roller 43 is lowered after the job of step S110 is started, and a lowering speed when the feeding roller 43 is lowered before the job of step S104 is started. May be separated.

As described above, in the present embodiment, the control unit 80 controls the separation motor 55 based on the detection of the sheet by the document presence / absence detection sensor 63, and the feeding ready state shown in FIG. To do. Further, the document adding operation can be detected based on the fact that the guide plate document detection sensor 62 detects the presence of an object such as a sheet or a user's hand in the feeding enabled state. When the document adding operation is detected, the separation motor 55 is controlled to switch from the feeding enabled state to the standby state. For this reason, the feeding roller 43 is positioned at a standby position where sheets can be stacked on the document tray 41 at the time of document addition, and the time until the start of image reading can be shortened without hindering the addition operation. The document reading can be speeded up.
<Second Embodiment>

  Next, a second embodiment will be described based on FIGS. The second embodiment is different from the first embodiment in that the document tray 41 can be raised and lowered. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 7A is a diagram showing an image reading apparatus 3a according to the second embodiment, and an ADF 4a of the image reading apparatus 3a is provided with an elevating mechanism 210 that moves the document tray 41 up and down. The lifting mechanism 210 includes a lift-up member 200 that lifts and lowers the document tray 41, a lifter motor 203 (see FIG. 8) that drives the lift-up member, and a lifter lower limit sensor 201 that detects the lower limit position of the document tray 41. ing. Further, the ADF 4 a is provided with a feed roller sensor 202 above the feed roller 43, and the feed position of the document (feed roller 43 and document tray 41) is positioned by the feed roller sensor 202. It is like that.

  Specifically, the CPU 80 can rotate the lift-up member 200 by rotating the lifter motor 203 in the normal direction to raise the document stacking surface of the document tray 41 (lift-up). Further, as shown in FIG. 7A, the CPU 80 lowers the feeding roller 43 when the document tray 41 is raised, so that the feeding roller sensor 202 detects OFF. Then, the feeding roller sensor 202 is monitored. As shown in FIG. 7B, the feeding roller sensor 202 is turned on when the feeding roller 43 comes into contact with the document stacked on the document tray 41 that is raised and is lifted. The lifter motor 203 is rotated forward until it is detected. As a result, the uppermost document on the document tray 41 can be stopped at a position where it can be fed. In the present embodiment, the lifter motor 203 and the lift-up member 200 constitute driving means for moving the document tray 41 as a sheet stacking unit up and down. Further, the switching means is constituted by a separation motor 55 as a raising / lowering means for raising and lowering the driving means and the feeding roller 43. In addition, raising / lowering is a concept including driving only ascending and descending due to its own weight.

  Further, as the originals on the original tray 41 are sequentially conveyed and read, the feeding roller 43 is also lowered and maintained in contact with the uppermost surface of the original. When the number of documents decreases and the feed roller sensor 202 detects OFF, the lifter motor 203 is rotated forward and stopped at a position where the feed roller sensor 202 detects ON. By repeating this, the uppermost document on the document tray 41 can always be kept at a position where it can be fed.

  In the present embodiment, it can be detected that the originals are fully loaded on the original tray 41. Specifically, as shown in FIG. 10, when the lift-up operation is executed, the CPU 80 detects that the feed roller sensor 202 is ON even when the feed roller 43 is lowered with the lifter lower limit sensor 201 turned on. If it is, it can be determined that the manuscript is full. If the CPU 80 detects that the document is full when the lift-up operation is performed, the CPU 80 determines that there is no need to raise the document stacking surface, and controls the lifter motor 203 not to raise the document stacking surface by rotating the lifter motor 203 by the amount of backlash. Thereby, it is possible to lift up smoothly when performing lift-up thereafter. It should be noted that the lifter motor 203 may be controlled not to move at all even when the lift-up operation is performed when the load is full.

  Further, the CPU 80 can rotate the lift-up member 200 by reversing the lifter motor 203 to lower the document stacking surface of the document tray 41 (lift-down). During this lowering, the CPU 80 monitors the lifter lower limit sensor 201 and lowers it until the lifter lower limit sensor 201 detects ON, thereby lowering the document stacking surface on the document tray 41 to the lower limit as shown in FIG. Can be stopped in position.

<Lift-up control using document addition detection>
FIG. 9 is a flowchart of lift-up control using document add-on detection. The CPU 80 reverses the lifter motor 203 and lifts it down so that the user can easily stack the documents on the document tray 41 when the power is turned on or when the job is finished (S201). In this state, the CPU 80 confirms whether the image reading job is started (S202).

  For example, when the user operates the operation unit 105 to start the image reading operation, the CPU 100 detects the operation of the operation unit 105 and notifies the CPU 80 of the start of the image reading job. Upon receiving the image reading job start notification, the CPU 80 determines that the job is started (YES in S202), and determines the presence / absence of documents on the document tray 41 based on the detection result of the document presence / absence detection sensor 63 (S210). If there is a document on the document tray 41 (YES in S210), the CPU 80 rotates the lifter motor 203 in the forward direction to lift the document tray 41 into a feedable state (S211). (S208). Then, it is confirmed whether or not the reading of the final document has been completed (S209). If the reading of the final document has been completed (YES in S209), the process is terminated. If reading has not been completed up to the final document (NO in S209), document conveyance and document reading are performed again (S208). By repeating this, the image reading is performed up to the final document stacked on the document tray 41.

  On the other hand, if there is no document on the document tray 41 in step S210 (NO in S210), the optical scanner unit 71 is scanned at a constant speed in the sub-scanning direction for the document placed on the document table glass 70. The image is read (S212).

  If the CPU 80 determines in step S202 that there is no job start (NO in S202), the CPU 80 determines whether the user has operated the operation unit 105 to perform image reading settings (for example, color mode and magnification settings). (S203). When the user operates the operation unit 105 and performs image reading setting, the CPU 100 notifies the CPU 80 of image reading setting. The CPU 80 can know that the image reading setting has been made by monitoring this notification. In the present embodiment, the image reading setting is monitored. However, the present invention is not limited to this. For example, an operation not related to image reading, such as setting the number of copies, may be confirmed. You may make it confirm that it approached after leaving once.

  If it is determined in step S203 that the image reading setting has not been performed (NO in S203), the CPU 80 confirms the job start notification again (S202). If it is determined in step S203 that the image reading setting has been performed (YES in S203), the CPU 80 causes the lifter motor 203 to rotate forward to lift up the document tray 41 (S204).

  Next, the CPU 80 determines whether or not the user is trying to add a document by performing the document addition detection described above (S205). When the CPU 80 detects that the user is trying to add a document (YES in S205), the document of the user is determined that the document tray 41 is in a lifted up state (feedable state) as shown in FIG. 7B. The loading operation will be hindered. Therefore, the CPU 80 reverses the lifter motor 203 and lifts it down to enter a standby state (S201). If the CPU 80 determines in step S205 that there is no additional document (NO in S205), the CPU 80 checks the presence / absence of the document on the document tray 41 by the document presence / absence detection sensor 63 (S206). By this confirmation, it is possible to detect whether or not the user has removed the document loaded on the document tray 41 once.

  If there is no document on the document tray 41 in step S206 (NO in S206), the CPU 80 determines that the user once removed the document stacked on the document tray 41. Then, in preparation for the case where the user sets the document again on the document tray 41, the lifter motor 203 is reversely rotated to perform the lift-down (S201). If it is determined in step S206 that there is a document on the document tray 41 (YES in S206), the CPU 80 checks whether the job has been started (S207).

  When the CPU 80 determines in step S207 that there is no job start (NO in S207), the CPU 80 determines again whether the user is trying to add a document (S205). If the CPU 80 determines in S207 that there is a job start (YES in S207), the CPU 80 performs the document conveyance and image reading described above (S208) and ends the process. In this case, since the document conveyance is started from the lifted state as shown in FIG. 7B, the document conveyance is started after the lift-up operation is performed from the lifted state as shown in FIG. 7A. , Can speed up the process.

  Even if the document tray 41 can be moved up and down by the above flow, it is possible to speed up document conveyance and document reading by the ADF 4a without hindering the user's document addition operation.

  In the above-described embodiment, the control units 20 and 106 are provided on the image reading device 3 side and the device main body 2 side. However, the present invention is not limited to this, and is provided on the device main body 2 side, for example. Alternatively, the image reading device 3 may be controlled by the control unit. Further, for example, the shutter provided in the sheet feeding portion may be released based on the lowering of the feeding roller 43. In this case, since the shutter is closed when the originals are added, the originals stacked on the original tray 41 can be prevented from entering the conveyance path.

  Furthermore, in the second embodiment, both the feed roller 43 and the document tray 41 are configured to be movable up and down. However, for example, only the document tray 41 may be configured to be movable up and down. The switching means is constituted by the driving means for raising and lowering the tray. Further, the feeding roller 43 may be configured to be lifted and lowered by a driving means such as a solenoid.

  In the above-described embodiment, the sheet conveying device, the image reading device, and the image forming device are divided for convenience of explanation. However, for example, the image reading apparatus can be said to be a sheet conveying apparatus including an image reading unit, and the image forming apparatus includes an image forming unit that forms an image on a sheet based on an image read by the image reading unit. It can also be said to be a sheet conveying apparatus.

20: control unit, 41: sheet stacking unit (document tray), 43: sheet feeding unit (feeding roller), 55: switching unit, lifting unit (separation motor), 62: sheet stacking detection unit (guide plate document detection) Sensor), 63: sheet presence / absence detection means (document presence / absence detection sensor), 200/203: switching means, drive means (lift-up member, lifter motor)

Claims (11)

A sheet stacking unit on which sheets are stacked;
Sheet presence / absence detection means for detecting whether or not a sheet is stacked on the sheet stacking unit;
Sheet feeding means for feeding the sheets stacked on the sheet stacking unit;
A feedable state in which the sheet feeding unit and the sheets stacked on the sheet stacking unit are in contact with each other, and a standby state in which the sheet feeding unit and the sheets stacked on the sheet stacking unit are separated from each other Switchable switching means,
Sheet stacking detection means for detecting the presence of an object in a space above the sheet stacking surface of the sheet stacking unit and higher than the maximum stacking height of sheets in the sheet stacking unit;
Based on the detection of the sheet by the sheet presence / absence detection unit, the switching unit is controlled to be in the feedable state, and based on the sheet stacking detection unit detecting the presence of an object in the feedable state. And a control unit that controls the switching means to switch from the feeding enabled state to the standby state.
A sheet conveying apparatus. The switching means includes an elevating means for elevating and lowering the sheet feeding means,
The control unit controls the elevating means to switch between the feeding enabled state and the standby state;
The sheet conveying apparatus according to claim 1. The switching means includes a driving means for raising the sheet stacking unit,
The control unit controls the driving unit to switch between the feeding enabled state and the standby state;
The sheet conveying apparatus according to claim 1 or 2, The control unit controls the switching unit based on the fact that the sheet presence / absence detection unit detects a sheet and detects that an operation unit operated by a user is operated, and the feeding enabled state And
The sheet conveying device according to any one of claims 1 to 3, wherein The control unit controls the switching unit after a predetermined time has elapsed after the sheet presence / absence detection unit detects a sheet, to enable the feeding.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The control unit sets the descending amount of the feeding unit when the sheet stacking detection unit detects the presence of an object and then enters the standby state again after the standby state. Less than the descending amount of the feeding means when the sheet stacking detection means makes the feeding ready state before detecting the presence of an object,
The sheet conveying apparatus according to any one of claims 2 to 5, wherein A regulation unit that regulates the position in the width direction orthogonal to the sheet conveyance direction of the sheets stacked on the sheet stacking unit;
The sheet stacking detection means is provided in the restriction unit.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The sheet stacking detection means includes an optical sensor,
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The sheet stacking detection means includes a plurality of optical sensors.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. An image reading unit that reads an image of the sheet fed by the sheet feeding unit;
The sheet conveying apparatus according to claim 1, wherein An image forming unit that forms an image on a sheet based on an image read by the image reading unit;
The sheet conveying apparatus according to claim 10.

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