JP2008122494A - Document reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a period of time required till the start of reading a document and to prevent a lot of stacked documents from being deformed. <P>SOLUTION: The document reader 1A2 includes: a document tray 2B on which a plurality of documents can be placed; document reading means S1 and S2 by which while the documents placed on the document tray are conveyed by a conveying means one at a time, the image data of each of the documents is read; and a paper ejection tray 3B on which the documents read by the document reading means are ejected. In the document reader 1A2, the conveying means has: an introducing roller 4B by which each of the documents placed on the document tray is introduced to a conveying path; conveying rollers R1 to 5 which convey these documents; and a paper ejection roller 6R by which the documents conveyed are ejected onto the paper ejection tray. The document tray placing section of the document tray has a tray movable part 2B1 raised so that the uppermost one of the documents in the document tray is brought into close contact with the introducing roller or lowered. When raised toward the introduction roller, the tray movable part is increased in moving speed during the raising process. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a document reading apparatus provided in an image forming apparatus such as an electrophotographic system or an electrostatic recording system in a scanner, a facsimile machine, a copying machine or the like, and more particularly, a pickup that serves as a document transport introduction unit for a document placed on a document tray. The present invention relates to a document reading apparatus including an elevating unit that is brought close to a roller.

  As an image reading method of a document reading device provided in a copying machine or the like, there are generally two methods, a document fixing method and an automatic document conveying method.

  In the document fixing method, a user places a document on a transparent platen, and among the image reading means including a light source, a mirror group, a lens, and a CCD provided under the platen, the light source and the mirror group are used as the document. The original image is scanned while being moved, and the scanning light reflected from the mirror is imaged on the CCD via the lens, and the original image is digitized.

  On the other hand, in the automatic document feeding method, a light source of an image reading unit is applied to a document which is conveyed by an automatic document feeder (hereinafter referred to as “SPF (Single Pass Feeder)”) and passes on a transparent platen (scanned portion). The image of the original is scanned and the image is read while the mirror group is stationary.

  In the automatic document conveyance method, a document that the user wants to read is placed on the document tray of the SPF, and the document is automatically conveyed and the image of the document is read simply by pressing the start key. It is more convenient than the fixed method.

  In recent years, with the increase in the speed of the print processing unit of the image forming apparatus, the document tray, which has conventionally had a stacking capacity of 10 or more sheets, has become a mechanism capable of stacking 200 to 300 documents. The amount of originals loaded in the reading apparatus has increased significantly.

  In addition, the document tray of the document reading apparatus with the document stacking amount increased in this way is configured to be movable in the document stacking direction according to the number of stacked documents. However, since the document feed point is generally executed from the uppermost surface of the loaded document, it is waiting at the home position located at the lowermost end portion of the document tray except when the reading process is executed. Generally, when a small amount (several originals) is loaded on such an original tray, it has been a problem that the rise time of the original tray until the start of reading elapses more than necessary.

As a conventional technique for solving such a problem, a document stacking table (tray movable portion) that is driven to move in a direction close to and away from a pickup unit that takes out a document placed at an extraction position is provided in a tray that holds a document. When the document held on the tray is in the supply state, the document stacking table is displaced so that the document closest to the pickup unit held on the tray is placed at the take-out position, and the document is loaded on the tray. Document reading having a function of controlling the tray body of the document tray to be displaced to a standby position that is closer to the pickup unit than the position when the maximum amount of document is held on the tray when in the standby state of waiting. An apparatus is disclosed in Patent Document 1. By enabling the document tray to be driven to be displaced by such control, it is possible to shorten the time required from the time when the sheet body is held on the tray until the sheet body is taken out from the tray by the pickup means.
JP 2004-001928 A

  However, when the document reading operation is started after the tray body of the document tray is driven to be displaced so that the document close to the pickup unit is arranged close to the take-out position according to the number of documents loaded on the tray, There is a problem in that the document on the uppermost surface of the documents stacked on the tray frequently deforms.

  Accordingly, the present invention has been made in view of the above-described problems of conventional document reading apparatuses, and an object of the present invention is to shorten the document reading start time and prevent deformation of stacked documents. It is an object of the present invention to provide a new and improved original reading apparatus.

  In order to solve the above-described problem, according to an embodiment of the present invention, a document tray on which a plurality of documents can be stacked and a document loaded on the document tray is transported one by one by a transport unit. In a document reading apparatus comprising a document reading unit for reading image data of a document and a discharge tray for stacking documents discharged after being read by the document reading unit, the transport unit is stacked on the document tray. An introduction roller that introduces a document into a conveyance path provided in the document reading device, a conveyance roller that conveys the document introduced into the conveyance path, and a discharge that discharges the document conveyed in the conveyance path to a discharge tray. A document roller, and the document placement portion of the document tray is provided with a movable tray portion that moves up and down so that the uppermost surface of the document in the document tray is close to the introduction roller. B When moved upward toward La, document reader moving speed of the tray moving part, characterized in that it is accelerated is provided between such upward movement step.

  With this configuration, after detecting the arrival of the uppermost surface of the document loaded on the document tray, the paper reaches the paper feed point of the pickup roller serving as an introduction roller for correcting the deformation of the uppermost surface of the document. Therefore, the original reading start time is shortened, and the correction time of the original on the uppermost surface by the pick-up roller is secured, and the deformation of the original can be prevented.

  At this time, in the above-described embodiment, the tray movable unit may be arranged at the lowermost end of the up-and-down movement range of the tray movable unit when the document is not placed on the document tray.

  With such a configuration, even when the document tray has the same capacity, a larger number of documents can be stacked on the document tray. The deformation of the original on the uppermost surface of the original is prevented.

  At this time, in the above embodiment, the document tray is provided with document placement detection means for detecting that the document is placed on the document placement portion, and the document placement detection means allows the document to be placed on the document placement portion. When it is detected that the tray has been placed, the tray movable unit may move up until the uppermost surface of the document reaches the introduction roller.

  With this configuration, since the drive source that moves the tray movable unit is activated after detecting that the document is placed on the document placement unit of the document tray, the document reading starts more reliably. It is possible to prevent the deformation of the document while shortening the time.

  At this time, in the above embodiment, the upward movement of the tray movable unit is a constant speed upward movement when the upward movement is started, and may be accelerated and moved after a predetermined time has elapsed.

  With this configuration, the upward moving speed of the tray movable unit is switched from constant speed to acceleration, so that the feeding speed that takes earlier is faster than when the pickup roller reaches the paper feed point by only constant speed upward movement. Since the paper point can be reached, the correction time of the uppermost document by the pickup roller is obtained, and the deformation of the uppermost document of the document stacked on the document tray is prevented.

  At this time, in the above-described embodiment, the constant speed rising movement time of the tray movable part may be a movement time for increasing the distance of at least 1/2 to 2/3 of the rising region of the tray movable part. .

  By adopting such a configuration, the time when the topmost surface of the document reaches the paper feed point, and the time required to start the acceleration ascending movement based on the time required to correct the deformation of the topmost surface of the document by the pickup roller. When setting the, the document reading start time is shortened more significantly by starting the acceleration rising movement after the moving time of the distance to perform the uniform ascending movement within such a data range, and the original reading start time is shortened more significantly. It is possible to prevent the deformation of.

  At this time, in the above-described embodiment, the raising and stopping of the tray movable unit may be executed based on an increase in the load of the drive source that moves the tray movable unit up and down.

  With such a configuration, the load (torque) of the drive source by the rotational drive that moves the tray movable portion on which the document is placed increases as the uppermost surface of the document comes into contact with the pickup roller. When the drive source increases, the operation of the drive source that activates the upward movement of the tray movable unit is stopped, and control when the upward movement of the tray movable unit of the document tray is stopped can be easily executed.

  As described above, according to the present invention, after a document is stacked on the document tray, the moving speed when moving the topmost surface of the document to the position of the pickup roller serving as the document feed point by the tray movable unit is constant. By changing from the movement to the acceleration movement, the uppermost surface of the document reaches the document feeding point quickly. For this reason, the correction time of the original on the uppermost surface by the pickup roller is ensured, and the original read start time is shortened, and deformation of the original stacked in large quantities can be prevented.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  First, a first embodiment of a document reading apparatus according to the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing the overall configuration of an image forming apparatus provided with a document reading apparatus according to the present embodiment, and FIG. 2 is a partial detail view showing the configuration of the apparatus main body of the image forming apparatus.

  In the present embodiment, the image forming apparatus 1A uses a predetermined sheet-like recording sheet (hereinafter referred to as a sheet) as a recording medium by electrophotographic processing of image data read by a scanner or the like and image data transmitted from the outside. A sheet feeding tray 8 on which a plurality of sheets P can be stacked, and sheet conveyance for conveying the sheet P supplied from the sheet feeding tray 8 to the image forming unit 14. And a sheet feeding tray 8 that can automatically supply the sheet P. Above the image forming apparatus 1A, the document reading apparatus 1A2 of the present embodiment is provided so that the upper surface of the document placing table 21 can be opened and closed.

  As shown in FIGS. 1 and 2, the image forming apparatus 1 </ b> A mainly includes an exposure unit 1, a developing device 2, a photosensitive drum 3, a charger 4, a charge eliminating device 41, a cleaner unit 5, a fixing unit 6, and a sheet conveyance. The apparatus main body 1A1 includes an apparatus 7, a paper feed tray 8, a paper discharge tray 9, a transfer mechanism 10, and the like, and an automatic document processing apparatus 1A2.

  A document placing table 21 made of transparent glass on which a document is placed is provided on the upper surface of the apparatus main body 1A1. Above the document placing table 21, the automatic document processing device 1A2 is swingably opened upward. On the other hand, a scanner unit 22 serving as a document reading unit that reads image data of a document is disposed below the document placing table 21.

  Below the scanner unit 22, an exposure unit 1, a developing device 2, a photosensitive drum 3, a charger 4, a charge removal device 41, a cleaner unit 5, a fixing unit 6, a paper transport device 7, a paper discharge tray 9, and a transfer mechanism. 10 is disposed, and a paper feed tray 8 in which the paper P is stored is disposed below.

  The exposure unit 1 performs exposure by irradiating the surface of the photosensitive drum 3 uniformly charged by the charger 4 with laser light according to image data (image data for printing) output from an image processing unit (not shown). Thus, the electrostatic latent image corresponding to the image data is written and formed on the surface of the photosensitive drum 3.

  The exposure unit 1 is disposed immediately below the scanner unit 22 and above the photosensitive drum 3, and employs laser scanning units (LSU) 13 a and 13 b including a laser irradiation unit 11 and a reflection mirror 12. In the present embodiment, in order to perform high-speed printing processing, a technique that uses a plurality of laser beams to reduce the speed of irradiation timing is adopted, and a two-beam technique is adopted.

  In the present embodiment, the laser scanning units (LSU) 13a and 13b are used for the exposure unit 1, but the light emitting elements arranged in an array, for example, an EL or LED writing head may be used. good.

  As shown in FIG. 2, the photosensitive drum 3 has a substantially cylindrical shape, is disposed below the exposure unit 1, and is rotated in a predetermined direction (the direction of arrow A in the figure) by a driving unit and a control unit (not shown). So that it is controlled. Along the outer peripheral surface of the photosensitive drum 3, the sheet peeling claw 31, the cleaner unit 5, and the charger 4 as an electric field generating unit are directed toward the downstream side in the rotation direction of the photosensitive drum 3 with reference to the position after the image transfer is completed. The developing device 2 and the charge eliminating device 41 are arranged in this order.

  The sheet peeling claw 31 is disposed so as to be able to contact and separate from the outer peripheral surface of the photosensitive drum 3 by a solenoid 32. When the unfixed toner image on the photosensitive drum 3 is transferred to the paper P with the paper peeling claw 31 in contact with the outer peripheral surface of the photosensitive drum 3, the paper peeling claw 31 sticks to the surface of the photosensitive drum 3. The sheet P is peeled off. Note that a driving motor or the like may be adopted as the driving means for the sheet peeling claw 31 instead of the solenoid 32, and other driving means can be selected.

  The developing device 2 visualizes the electrostatic latent image formed on the photosensitive drum 3 with black toner, and the charging device 4 is rotated in the rotation direction of the photosensitive drum 3 (the direction of arrow A in the figure). It is arranged substantially horizontally (right side in the figure) on the downstream side and on the side of the photosensitive drum 3. A registration roller 15 is disposed below the developing unit 2 on the upstream side in the recording medium conveyance direction.

  The registration roller 15 aligns the front end of the paper P supplied from the paper feed tray 8 and the toner image on the photoconductive drum 3 and conveys it between the photoconductive drum 3 and the transfer belt 103 (not shown). The operation is controlled by the drive means and the control means.

  The charger 4 is a charging means for uniformly charging the surface of the photosensitive drum 3 to a predetermined potential, and is disposed above the photosensitive drum 3 and in the vicinity of the outer peripheral surface thereof. In this embodiment, the charger type charger 4 is used. However, a contact type roller type or a brush type may be used.

  The static eliminator 41 is a pre-transfer static eliminator for lowering the surface potential of the photosensitive drum 3 in order to facilitate the transfer of the toner image formed on the surface of the photosensitive drum 3 to the paper P. It is arranged downstream of the developing device 2 in the rotation direction and below the photosensitive drum 3 and close to the outer peripheral surface thereof. In the present embodiment, the static eliminator 41 is configured using a static elimination electrode. However, a static elimination lamp may be used instead of the static elimination electrode, or static elimination may be performed by other methods. .

  The cleaner unit 5 removes and collects toner remaining on the surface of the photosensitive drum 3 after development and image transfer. The cleaner unit 5 is located at a position substantially opposite to the developing device 2 with the photosensitive drum 3 interposed therebetween. The drum 3 is disposed substantially horizontally (left side in the drawing) on the side.

  As described above, the electrostatic image visualized on the photosensitive drum 3 is applied from the transfer mechanism 10 onto the paper P on which the electric field having the opposite polarity to the electric charge of the electrostatic image is conveyed. Transferred onto P. For example, when the electrostatic image has a charge of (−) polarity, the applied polarity of the transfer mechanism 10 is (+) polarity.

  As shown in FIG. 2, the transfer mechanism 10 is bridged by a driving roller 101, a driven roller 102, and other rollers, and has a predetermined resistance value (in this embodiment, 1 × 10 9 to 1 × 10 13 Ω · cm). A transfer belt unit having a range), and the transfer belt 103 is disposed below the photosensitive drum 3 so that the surface of the transfer belt 103 is in contact with a part of the outer peripheral surface of the photosensitive drum 3. Yes. The transfer belt 103 conveys the paper P while pressing it against the photosensitive drum 3.

  An elastic conductive roller 105 capable of applying a transfer electric field with a conductivity different from that of the driving roller 101 and the driven roller 102 is disposed at the contact portion 104 between the photosensitive drum 3 and the transfer belt 103.

  The elastic conductive roller 105 is made of a soft material such as elastic rubber or foamable resin. Since the elastic conductive roller 105 has elasticity, the photosensitive drum 3 and the transfer belt 103 are not in line contact but in surface contact having a predetermined width (referred to as a transfer nip). The transfer efficiency to P can be improved.

  Further, on the downstream side of the transfer area of the transfer belt 103 in the paper conveyance direction, a static elimination roller 106 is transferred to neutralize the electric field applied to the conveyed paper P in the transfer area and smoothly carry it to the next process. It is arranged on the back side of the belt 103.

  In addition, the transfer mechanism 10 is provided with a cleaning unit 107 that removes dirt from the residual toner on the transfer belt 103 and a plurality of charge removal mechanisms 108 that perform charge removal on the transfer belt 103. As a technique for performing static elimination used in the static elimination mechanism 108, there is a technique of grounding through an apparatus, or a technique of positively applying a polarity opposite to the polarity of the transfer electric field.

  The electrostatic image (unfixed toner) transferred onto the paper P by the transfer mechanism 10 is conveyed to the fixing unit 6 and is pressurized and heated to melt the unfixed toner and be fixed on the paper P. .

  As shown in FIG. 2, the fixing unit 6 includes a heating roller 6a and a pressure roller 6b. The heating roller 6a is rotated while the sheet P is sandwiched between the heating roller 6a and the pressure roller 6b. And the pressure roller 6b, the toner image transferred onto the paper P is melted and fixed. A conveyance roller 16 that conveys the paper P is provided downstream of the fixing unit 6 in the paper conveyance direction.

  The heating roller 6a is provided with a sheet peeling claw 611, a thermistor 612 serving as a roller surface temperature detecting member, and a roller surface cleaning member 613 on the outer peripheral portion, and the heating roller surface is set to a predetermined temperature (fixing setting) on the inner peripheral portion. A heat source 614 having a temperature of approximately 160 to 200 ° C. is provided.

  The pressure roller 6b is provided with a pressure member 621 that can be pressed against the heating roller 6a at a predetermined pressure amount at both ends of the roller, and further, on the outer periphery of the pressure roller 6b. Similarly to the outer periphery of the heating roller 6a, a sheet peeling claw 622 and a roller surface cleaning member 623 are disposed.

  As shown in FIG. 2, the fixing unit 6 is configured to remove unfixed toner on the conveyed paper P at a pressure contact portion 600 (called a fixing nip portion) between the heating roller 6a and the pressure roller 6b. The unfixed toner is fixed on the paper P by a throwing action on the paper P by the pressure contact force between the heating roller 6a and the pressure roller 6b.

  The paper feed tray 8 is for accumulating a plurality of sheets (paper sheets) on which image data is output (printed). The exposure unit 1, the developing device 2, the photosensitive drum 3, the charger 4, the static elimination The image forming unit 14 is configured below the image forming unit 14 including the apparatus 41, the cleaner unit 5, the fixing unit 6, and the like. A paper pickup roller 8 a is disposed on the upper side of the paper discharge side of the paper feed tray 8.

  The sheet pickup roller 8a picks up the sheets P stacked and accommodated in the sheet feed tray 8 one by one from the uppermost layer, and moves toward the downstream side (for convenience, the flow-out side (cassette side) of the sheet P is upstream and discharged). The paper side is the downstream side.) The paper is conveyed to the registration roller 15 (also referred to as "idle roller") side on the paper conveyance path 7a constituting the paper conveyance device 7.

  In the image forming apparatus 1A according to the present embodiment, for the purpose of performing high-speed printing processing, a plurality of standard size sheets P can be stored in each tray below the image forming unit 14 in a plurality of sheets. On the other hand, a large-capacity paper feed cassette 81 capable of storing a plurality of types of paper is disposed on the side of the apparatus, and mainly above the large-capacity paper feed cassette 81. A manual feed tray 82 corresponding to printing of an irregular size is provided.

  The paper discharge tray 9 is disposed on the side of the apparatus opposite to the manual feed tray 82. Further, instead of the paper discharge tray 9, a post-processing device (device for performing stapling, punching, etc.) of paper discharge, a multi-stage paper discharge tray, and the like can be arranged as options.

  Here, a paper conveyance process corresponding to the processing mode by the paper conveyance device 7 in the image forming apparatus 1A will be described.

  As shown in FIG. 2, the paper P that matches the print request is selected from the plurality of paper feed trays 8 and is transported to the registration rollers 15 by the transport rollers in the paper transport path 7a.

  The paper P that has reached the registration roller 15 and has stopped once is conveyed to the transfer mechanism 10 when the registration roller rotates again at the timing when the leading edge of the paper P matches the image data on the photosensitive drum 3, and the paper P After an unfixed toner image (image data) is transferred from the photosensitive drum 3 to the upper side, the toner image is fixed on the paper P by the fixing unit 6 and discharged to the paper discharge tray 9.

  In the conveyance path in the sheet conveyance path 7a, the sheet discharge tray from the fixing unit 6 onward is processed by the processing mode (copier mode, printer mode, FAX mode) of the image forming apparatus 1A and the printing processing method (single-sided printing, duplex printing). The transport method up to 9 is different.

  Usually, in the copier mode, since the user performs an operation in the vicinity of the image forming apparatus 1A, a method called “face-up discharge” in which the printing surface is discharged with its upper side being used is often used.

  On the other hand, in each mode such as printer, FAX, etc., a “face-down discharge” method that aligns the page order of the discharged paper P because the user is not in the vicinity of the image forming apparatus 1A is often used.

  Accordingly, in the image forming apparatus 1A, before the sheet P that has passed through the fixing unit 6 is discharged to the sheet discharge tray 9, the sheet that meets the above-described purpose is discharged through a plurality of conveyance paths. ing.

  Next, the automatic document processing apparatus (document reading apparatus) 1A2 according to the present embodiment will be described in detail with reference to the drawings. FIG. 3 is an explanatory diagram showing the overall configuration of the automatic document processing apparatus according to the present embodiment.

  As shown in FIGS. 2 and 3, the automatic document processing apparatus 1A2 is provided above the scanner unit 22 above the image forming apparatus 1A so that the upper surface of the document table 21 can be opened and closed.

  The automatic document processing apparatus 1A2 also includes a document tray 2B on which a plurality of documents are stacked, and a document on which image data of the document is read while the documents stacked on the document tray 2B are transported one by one by a transport unit. Image reading sections S1 and S2 serving as reading means, and a discharge tray 3B for stacking and discharging image data read originals are provided.

  A document conveyance path in which the documents stacked on the document tray 2B are provided in the automatic document processing apparatus between the document tray 2B and the discharge tray 3B via the first image reading unit S1 and the second image reading unit S2. Pickup roller 4B serving as an introduction roller to be introduced into H1, feeding roller 5A for feeding a document drawn by this pickup roller 4B toward image reading portions S1 and S2, a document positioned at the top and other documents A document conveying path H1 having a substantially C-shape is provided, which includes a separating roller 5B for distributing the document and rollers R1 to R6 for conveying the document introduced into the document conveying path H1.

  Rollers R1, R2, R4 and R5 are transport rollers for transporting the document at a predetermined speed in the document transport path H1.

  The roller R3 is a registration roller that starts rotating in synchronization with the image data reading timing in the image reading units S1 and S2. Prior to the reading timing, the document (paper P) conveyed from the document tray 2B has its front end brought into contact with the stopped registration roller R3 to correct skewing, and is then rotated by the registration roller R3 that has started rotating. It is conveyed to the image reading units S1 and S2 at a predetermined reading timing.

  The roller R6 is a discharge roller that discharges the document (paper P) for which the image data reading process has been completed to the discharge tray 3B.

  In the document transport path H1, the first image reading unit S1 facing the document placing table 21 provided in the image forming apparatus 1A has a predetermined gap with respect to the first document reading table 10A provided in the document placing table 21. And the platen 10B is disposed. When the document passes through the first image reading unit S1 between the first document reading table 10A and the platen 10B, image data from the surface of the document is read by the CCD reading unit 22A provided in the scanner unit 22 of the image forming apparatus 1A. Is read.

  In the document transport path H1, a platen glass 16B is disposed on the upper surface side of the second document reading table 16A provided in the second image reading unit S2 located on the downstream side of the first image reading unit S1.

  Also, a CCD 8B, which is an image reading element of the present invention, is disposed together with the mirrors 22B to 25B and the lens 26B in a portion surrounded by the document transport path H1 inside the automatic document processing apparatus 1A2.

  The CCD 8B faces the second image reading unit S2 via the mirrors 22B to 25B, the lens 26B, and the platen glass 16B. When the document passes through the second image reading unit S2 between the second document placing table 16A and the platen glass 16B, the image data is read from the back side of the document by the CCD 8B.

  When reading single-sided originals that read image data from only one side of the original, the original fed out by the rotation of the pickup roller 4B in contact with the uppermost surface of the original placed on the original tray 2B is rotated by the rotation of the feed roller 5A. Guided into the transport path H1. In the present embodiment, the document placing portion of the document tray 2B is provided with a tray movable portion 2B1 that moves up and down so that the uppermost surface of the document in the document tray 2B is close to the pickup roller 4B. The configuration of the tray movable unit 2B1 and the operation control of the up and down movement will be described later.

  Thereafter, the document guided into the document transport path H1 by the rotation of the feeding roller 5A is fed into the document tray 2B by a separating roller 5B that rotates in the same direction as the feeding roller 5A. Returned, only one original positioned at the top is sent out into the original transport path H1.

  The document sent out from the document tray 2B is transported in the document transport path H1 by the rotation of the transport rollers R1 and R2, and is transported toward the first image reading unit S1 at a predetermined timing by the rotation of the registration roller R3.

  While the original passes through the first image reading unit S1, the image data on the surface is read by the CCD reading unit 22A of the scanner unit 22 including the light source unit 13B stopped below the first image reading unit S1. The document from which the image data on the front surface is read is discharged to the discharge tray 3B by the rotation of the transport rollers R4 and R5 and the discharge roller R6.

  When reading double-sided originals that read image data from both sides of the original, one original sent into the original transport path H1 is read from the front side image data by the first image reading unit S1 in the same way as when reading single-sided originals. After the processing is completed, the image data is guided to the second image reading unit S2 through the transport rollers R4 and R5, and the back surface image data is read by the CCD 8B when passing through the second image reading unit S2. The document for which the image data has been read from both sides is discharged to the discharge tray 3B by the rotation of the discharge roller R6.

  In the automatic document processing apparatus 1A2, the outside of the document transport path H1 is covered with an exterior panel 20B. In the exterior panel 20B, portions facing the upper surface side and the left side surface of the document transport path H1 are configured by a cover 9B.

  The cover 9B is openable and closable with the lower end of the left side surface in the figure as a hinge. A substantially L-shaped conveyance guide 31B is integrally fixed to the cover 9B so as to be disposed outside the upper surface side and the left side surface of the document conveyance path H1.

  Of the exterior panel 20B that forms the bottom surface of the automatic document processing apparatus 1A2, the portion facing the lower surface side of the document conveyance path H1 is configured by a first opening / closing member 6B. The first opening / closing member 6B is supported at the fulcrum 6A so as to be openable and closable around the axis orthogonal to the document conveyance direction toward the lower side of the automatic document processing apparatus 1A2.

  A second opening / closing member 7B is arranged inside the first opening / closing member 6B in the automatic document processing apparatus 1A2. The second opening / closing member 7B is supported at the fulcrum 7A so as to be openable and closable around the axis orthogonal to the document conveying direction toward the lower side of the automatic document processing apparatus 1A2.

  Next, a characteristic configuration of the tray movable portion 2B1 provided on the document tray provided in the automatic document processing apparatus 1A2 will be described with reference to the drawings. FIG. 4 is an explanatory diagram showing the configuration of the main part of the tray movable part included in the document tray provided in the automatic document processing apparatus of the present embodiment.

  The document placing portion of the document tray 2B is provided with a tray movable portion 2B1 that moves up and down so that the uppermost surface of the documents stacked on the document tray 2B is close to the pickup roller 4B. In the present embodiment, the tray movable portion 2B1 meshes with a rack 2B3 that is mounted so that a pinion 2B2 that is rotationally driven by a drive source (not shown) extends in a substantially vertical direction with respect to the tray movable portion 2B1. It is the structure which can raise / lower by the action | operation of. In addition, the raising / lowering means of the tray movable part 2B1 is not limited to that by the rack and pinion. For example, if the tip of the tray movable part 2B1 is configured to be close to the pickup roller 4B, for example, the base end of the tray movable part 2B1 Other configurations such as a configuration in which the side can swing around a fulcrum are also possible. In addition, raising / lowering operation control of tray movable part 2B1 is mentioned later.

  The pick-up roller 4B normally stops at a position that is an escape position with respect to the tray movable portion 2B1, as shown by a broken line in FIG. 4, and a photo (not shown) that the document is placed on the document tray 2B. When detected by a sensor or the like, as shown by the solid line in FIG. 4, the sheet moves downward from the retracted position toward the document feed point P1 that is in contact with the uppermost surface of the documents stacked on the document tray 2B. When the pickup roller 4B moved downward to the document feeding point P1 detects the arrival of the uppermost surface of the document, the pickup roller 4B corrects the deformation of the uppermost surface of the document by repeating a slight vertical movement, and then picks up the roller 4B. Rotates to shift to the document feeding process to the document transport path H1. The operation control of the pickup roller 4B will be described later.

  The pickup roller 4B and the paper feed roller 5A are rotatably connected and held by a pickup bracket 4B1, and the pickup bracket 4B1 is rotatable around a metal shaft portion 5A1 that serves as a support shaft of the paper feed roller 5A. As a result, the pickup roller 4B can be raised and lowered. Further, the pickup roller 4B and the paper feed roller 5A are rotated in the same direction by a gear train (not shown) provided inside the pickup bracket 4B1.

  A guide member 5B1 for guiding the leading end portion of the document placed on the document tray 2B is provided below the paper feed roller 5A. The document is pressed against the guide member 5B1 by the lowered pickup roller 4B, and the pickup is performed. The uppermost document is drawn by the rotation of the roller 4B. Note that the guide member 5B1 has a gap in the portion overlapping with the separating roller 5B disposed below the sheet feeding roller 5A in order to separate the document introduced from the pickup roller 4B into one sheet.

  Next, a control system of the image forming apparatus 1A according to the present embodiment will be described with reference to the drawings. FIG. 5 is a block diagram showing a configuration of the electric control unit of the image forming apparatus according to the present embodiment.

  As shown in FIG. 7, the image forming apparatus 1A according to the present embodiment stores image reading processing, image processing, image forming processing, paper P transport processing, and the like in a ROM (Read Only Memory) 55 in advance. In accordance with the program, a central processing unit (CPU) 54 serving as a control unit for each component included in the image forming apparatus 1A executes processing using a temporary storage unit such as a RAM (Random access Memory) 56 or the like. In place of the ROM 55 and the RAM 56, storage means such as an HDD (Hard Disk Drive) may be used.

  In the image forming apparatus 1A, document image data (document image data) read by the scanner unit 22 or document image data transmitted from each terminal device connected to a communication network (not shown) is transmitted via the communication processing unit 58. Are input to the image processing unit 57.

  The image processing unit 57 processes the document image data stored in the storage unit such as the RAM 56 into a print image suitable for printing (image formation on paper) by the above program.

  The image data for printing is input to the image forming unit 14. The image forming unit 14, a sheet conveying unit 59 that detects and controls various types of sheets in the sheet conveying path 7 a, and the paper discharge processing unit 60 that performs various types of detection and control of sheets in the fixing unit 6 and the discharge roller 17 Each drive control unit 62 is linked.

  The sheet conveyed by the sheet conveying unit 59 is subjected to a printing process in which image data is printed in the image forming unit 14 and then a fixing unit 6 that performs a fixing process on the printed sheet. The paper is discharged to a paper discharge tray 9 serving as a paper discharge portion. Note that detection signals from the pre-registration detection switch 596, the fixing detection switch 597, the paper discharge detection switch 598, and the like are input to the paper transport unit 59.

  The pre-registration detection switch 596 is a switch that detects whether or not a sheet has reached the registration roller 15. The fixing detection switch 597 is a switch that detects whether or not a sheet has reached the fixing unit 6. The paper discharge detection switch 598 is a switch that detects whether or not the paper is discharged.

  The image forming apparatus 1 </ b> A is provided with an operating condition setting unit 77. The operation condition setting unit 77 is configured to perform image formation or conveyance conditions of the image forming apparatus 1A according to an image formation request set by the user using the operation switches 76 or an image formation condition such as the type of recording medium (paper). The operation conditions are set.

  Further, the image forming apparatus 1A includes a reading unit (scanner unit 22), a paper transport unit 59, an image forming unit 14, a fixing unit 6, and a paper discharge processing unit 60 according to the operating conditions set by the operating condition setting unit 77. The operations of the original reading drive unit 64, the paper conveyance drive unit 66, the reverse conveyance drive unit 67, the print processing drive unit 68, the fixing drive unit 70, and the paper discharge drive unit 72, which are drive actuators of The operation synchronized with the instruction of the CPU 54 based on the program is performed under the control of the drive control unit 62.

  The document reading drive unit 64 is a drive actuator for the scanner unit 22. The paper transport drive unit 66 is a motor for driving the paper transport unit 59, specifically, the paper pickup roller 8a and the registration roller 15 on the paper transport path 7a. The reverse conveyance driving unit 67 is a driving motor for the reverse conveyance roller 18. The print processing drive unit 68 is a drive motor for the photosensitive drum 3. The fixing driving unit 70 is a driving motor for the heating roller 6 a and the pressure roller 6 b of the fixing unit 6. The paper discharge drive unit 72 is a drive motor such as a paper discharge roller 17. The drive motors of these drive units can be configured through a power transmission mechanism as appropriate using the same or different motors as drive sources.

  Further, the image forming apparatus 1A includes, as an optional configuration 74, a post-processing device (staples, punches, a multi-stage discharge tray, a shifter, etc.), an automatic document reading device (automatic document processing device 1A2, etc.), a large-capacity paper feed cassette. 81 can be arranged, and these optional configurations 74 have a control unit 74a in each optional configuration 74 separately from the control unit of the image forming apparatus 1A, and adjust timing with the apparatus via the communication processing unit 58. Configured to synchronize.

  The control unit 74a for controlling various optional configurations also serves as the control unit 1C for controlling the automatic document processing apparatus 1A2. In the present embodiment, as a function of the control unit 1C, document placement detection means 1C1 that detects that a document is placed on the document tray 2B, and elevation that detects a load of a drive source that moves the tray movable unit 2B1 up and down. The drive source load detection means 1C2, the tray movable part drive means 1C3 for operating the drive source for moving the tray movable part 2B1 up and down, and whether or not the uppermost surface of the document stacked on the document tray 2B has reached the pickup roller 4B. Document uppermost surface arrival detection means 1C4 to detect, when the uppermost surface of the document reaches the pickup roller 4B, it is driven to move downward from the escape position of the pickup roller 4B to the document feeding point P1 or during the sheet feeding process. Pickup roller driving means 1C5 for operating the driving source is included. As a function of the control unit 1C, in addition to the above-described units 1C1 to 1C5, there are a plurality of initialization units such as an optical unit (mirror, lens, CCD) related to document reading, a plurality of units arranged in the document conveyance path. A function of measuring various operation times such as a sensor initialization time, a detection time of whether or not a previous document is accumulated in the conveyance path, and the like may be separately provided.

  In this embodiment, the document placement detection means 1C1 is provided with a plurality of detection sensors (not shown) such as photosensors at predetermined intervals in the length direction of the document tray 2B, and the document placement on the document tray 2B. At the same time as detecting that a document is placed on the placement unit, it is possible to determine the paper size of the document loaded on the document tray 2B. The document size is determined by, for example, detecting the transmission / non-transmission of light of a plurality of photosensors provided at predetermined intervals in the length direction of the document tray 2B when compared with the A4 horizontal size. A large / small determination is executed in comparison with the A4 horizontal size.

  When the document placement detection means 1C1 detects that a document is placed on the document placement portion of the document tray 2B, the tray movable portion drive means 1C3 is activated, and a pickup roller whose uppermost surface of the document serves as an introduction roller The tray movable part 2B1 moves up until it reaches 4B. In the present embodiment, the ascending speed of the tray movable portion 2B1 is switched from a constant speed increase to an acceleration increase during the ascent movement in order to make the uppermost surface of the document reach the document feeding point P1 earlier. When the document placement detection unit 1C1 detects document placement, the pickup roller driving unit 1C5 operates to move the pickup roller 4B downward from the escape position toward the document feed point P1 as shown in FIG. .

  The document uppermost surface arrival detection means 1C4 determines whether or not the pickup roller 4B moved downward to the document feeding point P1 has reached the uppermost surface of the document at the document feeding point P1, based on the load applied to the pickup roller 4B. To detect. In the document uppermost surface arrival detection means 1C4, for example, a position detection sensor for detecting the position of the pickup roller 4B at the document feeding point P1 determines whether or not the uppermost surface of the document has reached the document feeding point P1. By executing this, the position of the uppermost surface of the document is detected, or is detected by an increase in the driving load of the pickup roller driving means 1C5 serving as a driving source for moving the pickup roller 4B downward from the standby position to the document feeding point P1. . The document uppermost surface arrival detection means 1C4 for detecting whether the uppermost surface of the document has reached the pickup roller 4B is not limited to this embodiment.

  After detecting the arrival of the uppermost surface of the document on the pickup roller 4B that has moved down to the document feeding point P1, the pickup roller 4B is operated so as to repeat a slight vertical movement via the pickup roller driving means 1C5. Correct the deformation of the top surface of the. Thereafter, the pickup roller 4B is rotationally driven via the pickup roller driving means 1C5, and the process proceeds to a paper feeding process in which the paper is fed sequentially from the uppermost document to the document conveyance path H1.

  The recording medium detection unit 78 detects that the leading edge of the paper reaches the fixing unit 6 or the carry-out unit. Specifically, the recording medium detecting unit 78 includes a conveyance time measuring unit 79a that measures the conveyance time of the sheet after the sheet is sent out from the registration roller 15 that introduces the sheet at the entrance of the sheet conveyance path 7a, and the registration roller. 15 includes a conveyance timing detection unit 79b that detects the conveyance timing of the sheet in the sheet conveyance path 7a based on the distance from the fixing unit 6 to be controlled and the discharge roller 17 and the conveyance speed of the sheet.

  In the present embodiment, the recording medium detection unit 78 is based on the conveyance timing of the recording medium detected by the conveyance timing detection unit 79b when the sheet arrives (enters) each of the fixing unit 6 and the paper discharge roller 17. To detect.

  Next, the up / down movement (up / down movement) operation of the tray movable portion 2B1 provided in the document tray 2B provided in the automatic document processing apparatus 1A2 of this embodiment will be described with reference to the drawings. FIG. 6 is a diagram showing the relationship between the rising speed and the position of the tray movable part for explaining the operation of the conventional method for moving the tray movable part upward, and FIG. 7 is a diagram showing the rise of the conventional tray movable part. FIG. 8 is a flowchart illustrating the movement operation, and FIG. 8 is a diagram illustrating the relationship between the rising speed and the position of the tray movable portion for explaining the operation of the moving method of the upward movement of the tray movable portion according to the present embodiment. FIG. 9 is a flowchart for explaining the upward movement operation of the tray movable part according to the present embodiment.

  In the conventional document reading apparatus, first, whether or not a read document is stacked on the document tray is detected by a detection sensor serving as a document placement detection unit (step S10). When the placement of the document on the document tray is detected, the start key is pressed (step S11), and then the pickup roller driving means is operated to move the pickup roller downward from the escape position to the document feed point (step S12). ).

  Further, when it is detected that the document is placed on the document tray, the tray movable unit driving means is operated, and the tray movable unit of the document tray is moved up within a predetermined time (step S13). At this time, conventionally, as shown in FIG. 6, the tray movable unit moves up and down at a constant speed from the lower limit position serving as the home position to the upper limit position serving as the document feeding point. When the uppermost surface of the document loaded on the document tray reaches and comes into contact with the pickup roller, the driving load of the tray movable unit driving means that rotates is increased (step S14), and when such an increase in driving load (torque) is detected. Then, the raising of the tray movable unit driving means is stopped, and the tray movable unit is stopped at the document feed point (step S15). After that, the pickup roller comes into contact with the uppermost surface of the document, and the pickup roller is repeatedly pressed up and down to correct the deformation of the uppermost surface of the document. The conveyance is executed (step S16). If an increase in the driving load of the tray movable unit driving unit is not detected in step S14, the process does not proceed to the next step until an increase in the driving load of the tray movable unit driving unit is detected.

  In the above-described step S13, the predetermined time during which the tray movable unit moves upward is the initialization time of various optical units (mirror, lens, CCD), etc. related to the document reading of the document reading device, and is arranged in the document transport path. The total of the initialization time of a plurality of sensors to be detected and the detection time of whether or not the previous original is staying in the conveyance path is shown. Such a predetermined time is a short time between several seconds and 15 seconds in a normal document reading apparatus.

  When a scan request is made when a small number of documents are loaded on the document tray of a document reader that can load a large number of documents, the distance that the tray movable part of the document tray rises is the same as when a large number of documents are loaded. Therefore, until the uppermost document reaches the document feed point, it is necessary to move up from the lowest position, which is the home position, to the document feed point. A predetermined time elapses between them. For this reason, the time required for correcting the deformation of the uppermost surface of the document by the pickup roller before the paper feeding process is not sufficiently secured, and the document on the uppermost surface among the documents stacked on the document tray is likely to be deformed. End up. In other words, when the number of stacked originals is small and the moving distance of the tray movable part is large, the original feeding process starts as soon as the uppermost surface of the original reaches within a predetermined time. Almost no longer secured.

  On the other hand, in the present embodiment, first, whether or not a read document is stacked on the document tray 2B is detected by a detection sensor serving as the document placement detection unit 1C1 (step S100). When the placement of the document on the document tray 2B is detected, the start key is pressed (step S101), and then the pickup roller driving means 1C5 is operated to lower the pickup roller 4B from the escape position to the document feeding point P1. Move (step S102).

  Further, when it is detected that a document is placed on the document tray 2B, the tray movable portion driving means 1C3 is activated, and the tray movable portion 2B1 of the document tray 2B is moved upward within a predetermined time (step S103). . At this time, when a large amount of documents are stacked on the document tray 2B, the distance between the document feed point and the top surface of the documents stacked on the document tray 2B is small, so that the top surface of the document is the pickup roller. It takes no time to reach 4B. For this reason, when the uppermost surface of the document comes into contact with the pickup roller 4B, an increase in the driving load of the tray movable portion driving means 1C3 that is rotationally driven is detected by the lifting drive source load detecting means 1C2 (step S104), and the tray movable portion driving means. The ascending drive of 1C3 is stopped, and the tray movable portion 2B1 is stopped at the document feed point P1 (step S105). Thereafter, the pickup roller 4B comes into contact with the uppermost surface of the document, and the pickup roller 4B is repeatedly pressed up and down to correct the deformation of the uppermost surface of the document. The document is transported (step S106).

  On the other hand, when a small amount of documents such as one or two sheets are stacked on the document tray 2B, the distance between the document feed point P1 and the top surface of the documents stacked on the document tray 2B is a large number of documents. Therefore, the time until the uppermost surface of the document reaches the pickup roller 4B is longer than that when a large amount of documents are stacked. Therefore, until the uppermost surface of the document comes into contact with the pickup roller 4B, the elevation drive source load detection unit 1C2 does not detect an increase in the driving load of the tray movable unit driving unit 1C3 that is rotationally driven (step S104).

  Thereafter, in the present embodiment, as shown in FIG. 8, the tray movable unit 2B1 is moved between the lower limit position L0 as the home position and the upper limit position L3 as the document feed point P1 during the upward movement process. The moving speed of 2B1 is accelerated from low speed to high speed. Specifically, first, the tray movable unit 2B1 moves up at a constant speed during the set time (the movement time of the distance from the lower limit position L0 to the position L1) (step S107). The set time (low speed rise time) in step S107 is based on the time required for the uppermost surface of the document to reach the document feed point P1 and the deformation of the uppermost surface of the document is corrected by the pickup roller 4B. Is set. Further, at this time, the moving speed of the tray movable portion 2B1 at a constant speed increases at a low speed, and the effect of preventing the deformation of the document on the uppermost side loaded in a large amount is shortened while shortening the document reading start time. For this reason, it is preferable that it is a movement time for increasing the distance of at least 1/2 to 2/3 in the rising region (between the lower limit position L0 and the upper limit position L3) of the tray movable portion 2B1.

  When the tray movable part 2B1 moves up at a constant speed at a low speed during the set time (step S107), the rotational load of the tray movable part driving means 1C3 is increased to accelerate the ascent speed of the tray movable part 2B1 to increase the speed. Switching to ascending (step S108). When the moving speed of the tray movable portion 2B1 is accelerated and switched to high speed to increase at a high speed, the uppermost surface of the documents stacked on the document tray 2B reaches the pickup roller 4B and comes into contact with it. When the drive load of the tray movable part driving means 1C3 to be increased is increased and, as shown in FIG. 8, such a drive load (torque) increase is detected by the elevating drive source load detection means 1C2 (step S109), the tray movable part drive means 1C3 Is stopped and the tray movable portion 2B1 is stopped at the document feed point P1 (step S105). Thereafter, the pickup roller 4B comes into contact with the uppermost surface of the document, and the pickup roller 4B is repeatedly pressed and pressed slightly to correct the deformation of the uppermost surface of the document. Then, the original is conveyed in the conveyance path, and the original reading process is executed (step S106).

  As described above, in the present embodiment, the tray movable portion 2B1 accelerates and rises after a lapse of a predetermined time. Therefore, compared to the conventional case where the tray moving portion 2B1 is raised at a constant speed, the tray movable portion 2B1 is earlier than the document feeding point P1 where the pickup roller 4B is located. Will arrive. For this reason, the correction time of the uppermost original document by the pickup roller 4B is obtained, and deformation of the original document can be prevented. That is, the document reading start time is shortened, and the correction time of the document on the uppermost surface by the pickup roller 4B is secured, and the document can be prevented from being deformed. If an increase in the driving load of the tray movable unit driving unit 1C3 is not detected in step S109, the process returns to step S104 and the next step is performed until an increase in the driving load of the tray movable unit driving unit 1C3 is detected. Does not progress to.

  As described above, in the present embodiment, the movement of the tray movable unit 2B1 to be moved upward is performed in order to bring the uppermost surface of the document stacked on the document tray 2B close to the pickup roller 4B that has been lowered to the paper feed point P1. Since the speed is accelerated between the rising and moving processes, the arrival at the document feeding point P1 of the pickup roller 4B that corrects the deformation of the document uppermost surface after detecting the arrival of the document uppermost surface loaded on the document tray 2B is reached earlier. To come. Therefore, it is possible to reach the document feeding point P1 earlier than the case where it reaches the feeding point P1 of the pickup roller 4B only by moving at a constant speed. The correction time of the document on the uppermost surface by the pickup roller 4B is ensured, and deformation of the document on the uppermost surface is prevented.

  Further, since the stop of the upward movement of the tray movable portion 2B1 is executed based on an increase in the load of the drive source that moves the tray movable portion 2B1 upward, the control for stopping the upward movement of the tray movable portion 2B1 of the document tray 2B is performed. Can be easily implemented.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the first embodiment described above, an image forming apparatus that outputs image data by an electrophotographic method is described as an example. However, the present invention is not limited to this, and a document to be read can be read. The present invention can also be applied to an image forming apparatus and other apparatuses using other methods as long as a document reading apparatus including a document conveying apparatus for conveying is mounted.

  In the first embodiment, the present invention is applied to a monochrome image forming apparatus in which one toner container is installed. However, the present invention is applied to a color image forming apparatus in which a plurality of toner containers are installed. The original reading apparatus can also be applied.

1 is an explanatory diagram showing the overall configuration of an image forming apparatus including such an apparatus according to a first embodiment of a document reading apparatus according to the present invention; FIG. FIG. 2 is a partial detail view showing the configuration of the apparatus main body of the image forming apparatus in the embodiment. FIG. 2 is an explanatory diagram illustrating an overall configuration of a document reading apparatus according to the same embodiment. 4 is an explanatory diagram illustrating a configuration of a main part of a tray movable unit included in a document tray provided in the document reading apparatus of the embodiment. FIG. FIG. 2 is a block diagram illustrating a configuration of an electric control unit of the image forming apparatus in the embodiment. It is a figure which shows the relationship between the raising speed for demonstrating operation | movement of the moving method of the raise movement of the conventional tray movable part, and the position of a tray movable part. It is a flowchart explaining operation | movement of the raise movement of the conventional tray movable part. It is a figure which shows the relationship between the raising speed and the position of a tray movable part for demonstrating operation | movement of the moving method of the raising movement of the tray movable part of the embodiment. It is a flowchart explaining operation | movement of the raise movement of the tray movable part of the embodiment.

Explanation of symbols

1A Image forming apparatus 1A2 Document reading apparatus (automatic document processing apparatus)
1C Control section 1C1 Document placement detection means 2B Document tray 2B1 Tray movable section 3B Discharge tray 4B Introduction roller (pickup roller)
5A Feed roller 21 Document placement table 22 Scanner unit H1 Document transport path R1, R2, R4, R5 Transport roller R3 Registration roller R6 Discharge roller S1 Document reading means (first image reading unit)
S2 Document reading means (second image reading unit)

Claims (6)

A document tray capable of stacking a plurality of documents, a document reading unit that reads image data of the document while conveying the documents stacked on the document tray one by one by the transport unit, and the document reading unit A document reading apparatus including a discharge tray on which a document to be discharged after reading is loaded.
The transport means includes an introduction roller that introduces a document stacked on the document tray into a transport path provided in the document reader, a transport roller that transports the document introduced into the transport path, and the transport path. A discharge roller that discharges the document conveyed in the discharge tray to the discharge tray,
The document placing portion of the document tray includes a tray movable portion that moves up and down so that the uppermost surface of the document in the document tray is close to the introduction roller,
When the tray movable unit moves upward toward the introduction roller, the moving speed of the tray movable unit is accelerated between the steps of the upward movement.   2. The document reading apparatus according to claim 1, wherein the tray movable unit is disposed at a lowermost end of an up-and-down movement range of the tray movable unit when a document is not placed on the document tray.   The document tray is provided with document placement detection means for detecting that a document is placed on the document placement section, and the document placed on the document placement section by the document placement detection means. 3. The document reading apparatus according to claim 1, wherein the tray movable unit moves up until the uppermost surface reaches the introduction roller.   4. The document reading apparatus according to claim 1, wherein the upward movement of the tray movable portion is a constant speed upward movement at the start of the upward movement and is accelerated and moved after a predetermined time has elapsed. .   5. The moving speed for moving the tray movable portion at a constant speed is a moving time for increasing the distance of at least 1/2 to 2/3 of the rising region of the movable tray portion. Document reader.   The document reading apparatus according to claim 1, wherein the raising / lowering of the tray movable unit is executed based on an increase in a load of a driving source that moves the tray movable unit up and down.

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