Patent Publication Number: US-6988723-B2

Title: Feeding and conveying device with wait position

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a sheet member feeding and conveying apparatus which is mounted on an image reading apparatus, an image forming apparatus and the like and which conveys a sheet member such as a document and a recording sheet. 
   2. Description of the Related Art 
   An image reading apparatus which reads an image formed on a document by automatically conveying one document or a plurality of documents sequentially to an image reading section provided with an image sensor, and an image forming apparatus which forms an image on a recording sheet by automatically conveying one recording sheet or a plurality of recording sheets sequentially to an image forming section provided with an inkjet head are equipped with sheet member feeding and conveying apparatuses in order to read an image and form an image effectively. As digital technology progresses, the time between reading an image of a document and conversion to digital data and the time for forming an image from digital data on a recording sheet are shortened. Moreover, in an image reading apparatus and an image forming apparatus, in order to efficiently feed and convey a lot of sheet members including documents and recording sheets, the number of sheet members which can be held in a sheet member feeding and conveying apparatus at a time has remarkably increased, which is 100 or more in the case of a copy sheet of 62 g/m 2  by basis weight, for example. 
   As such a prior art, a paper feeding apparatus provided with a deck on which a large number of sheet members can be placed and capable of manual paper feeding is disclosed in Japanese Unexamined Patent Publication JP-A 2-163227 (1990). Moreover, as another prior art, a paper feeding apparatus provided with a paper feeding table on which a large number of sheet members can be placed is disclosed in Japanese Unexamined Patent Publication JP-A 4-260547 (1992). Furthermore, as still another prior art, an automatic sheet material feeder provided with a document tray on which a plurality of sheet materials are placed is disclosed in Japanese Unexamined Patent Publication JP-A 10-194502 (1998). 
   In the aforementioned prior arts, a tray is placed in a waiting position where the spacing between a placed face of the tray and a pickup roller is the largest so that the user can make the tray hold the tray&#39;s maximum holding amount of sheet members when loading sheet members on the tray. Since the tray is placed in a waiting position even when the user loads and makes a few sheet members held, time of at least one second or more is required for displacing the tray from a waiting position to a position where the sheet members are placed in a take-out position where the pickup roller can take out the sheet members held on the tray. Therefore, the aforementioned time for displacing the tray is added to the duration from the time when the user makes sheet members held on the tray to the time when images formed on the sheet members are read or images are formed on sheet members, with the result that the time required for an image reading process and an image forming process becomes long. Particularly, in an image reading apparatus, it is exceedingly rare to read the maximum amount of sheet members which can be held on the tray, and the amount of sheet members to be read is normally one, a few or dozens at most. 
   SUMMARY OF THE INVENTION 
   Accordingly, an object of the invention is to provide a sheet member feeding and conveying apparatus which enables shortening the required duration from the time when a sheet member is held on a tray to the time when the sheet member is taken out of the tray by pickup means. 
   The invention provides a sheet member feeding and conveying apparatus comprising: 
   pickup means for taking out a sheet member placed in a predetermined take-out position; 
   a tray having a tray main body capable of displacement in directions close to and away from the pickup means, for holding sheet members; 
   tray driving means for driving the tray main body to be displaced in the directions close to and away from the pickup means; and 
   control means for controlling the tray driving means so as to, in a feeding state of feeding sheet members held on the tray, drive the tray main body to be displaced so that a sheet member closest to the pickup means held on the tray is placed in the take-out position, and in a waiting state of waiting for loading of sheet members on the tray, drive the tray main body to be displaced into a waiting position which is closer to the pickup means than a position at a time when a maximum holding amount of sheet members are held on the tray. 
   According to the invention, the tray main body is driven by the tray driving means controlled by the control means, in the waiting state of waiting for loading of sheet members on the tray, to be displaced into a waiting position closer to the pickup means than the position at the time when the maximum holding amount of sheet members are held on the tray, and in the feeding state of feeding sheet members held on the tray, to be displaced so that the sheet member closest to the pickup means held on the tray is placed in the take-out position. 
   Since the amount of displacement from the waiting position closer to the pickup means than the position at the time when the maximum holding amount of sheet members are held on the tray to the position where the sheet member closest to the pickup means held on the tray is placed in the take-out position is smaller than the amount of displacement from the waiting position at the time when the maximum holding amount of sheet members are held on the tray to the position where the sheet member closest to the pickup means held on the tray is placed in the take-out position, it is possible to shorten the duration from the time when a smaller amount than the tray&#39;s maximum holding amount of sheet members, for example, a few sheet members are loaded on the tray to the time when a sheet member is taken out by the pickup means. 
   Since the amount of sheet members handled in, for example, an image reading apparatus which reads images formed on sheet members is sufficiently smaller than the tray&#39;s maximum holding amount in general, it is possible to execute an image reading process at a high speed, by equipping the image reading apparatus with the sheet member feeding and conveying apparatus of the invention. 
   Further, in the invention it is preferable that the apparatus further comprises waiting position input means for inputting a waiting position, and that, in the waiting state, the control means controls the tray driving means so as to drive the tray main body to be displaced into a waiting position inputted by the waiting position input means. 
   According to the invention, in the waiting state, the tray main body is driven by the tray driving means to be displaced into a waiting position inputted by the waiting position input means, by inputting the waiting position in response to the amount of sheet members, for example, with the result that it is possible to certainly shorten the duration from the time when sheet members are loaded on the tray to the time when a sheet member is taken out by the pickup means. 
   Still further, in the invention it is preferable that the apparatus further comprises waiting position determining means for determining a waiting position based on the amount of sheet members loaded on the tray in a take-out operation executed before. 
   According to the invention, a waiting position is determined by the waiting position determining means based on the amount of sheet members loaded on the tray in a take-out operation executed before, with the result that it is possible to automatically determine a waiting position and shorten the duration from the time when sheet members are loaded on the tray to the time when a sheet member is taken out by the pickup means. 
   Still further, in the invention it is preferable that the pickup means is capable of displacement between a pickup position where a sheet member placed in a take-out position can be taken out and an evacuation position evacuated from the pickup position, the apparatus further comprises pickup driving means for driving the pickup means to be displaced between the pickup position and the evacuation position, and that the control means controls the pickup driving means so as to, in the feeding state, place the pickup means into the pickup position, and in the waiting state, place the pickup means into the evacuation position. 
   According to the invention, the pickup means is driven to be displaced between the pickup position and the evacuation position so as to be, in the feeding state, placed in the pickup position where a sheet member placed in the take-out position can be taken out, and in the waiting state, placed in the evacuation position evacuated from the pickup position. When the pickup means is placed in the evacuation position, the user can easily remove sheet members held on the tray from the tray. Therefore, for example, when an undesired sheet member is loaded on the tray by mistake, the user can easily remove the sheet member held on the tray from the tray and easily reload a desired sheet member on the tray, with the result that it is possible to prevent that an undesired sheet member is taken out by the pickup means and processed. 
   Still further, in the invention it is preferable that the apparatus further comprises sheet member detecting means for detecting that a sheet member is held on the tray, and that, in the waiting state, when the sheet member detecting means detects that a sheet member is loaded on the tray, the control means controls the pickup driving means so as to place the pickup means placed in the evacuation position into the pickup position after a lapse of preset loading completion waiting time for waiting for a time between loading of a sheet member and completion of loading. 
   According to the invention, in the waiting state, when the sheet member detecting means detects that a sheet member is loaded on the tray, the pickup means placed in the evacuation position is placed into the pickup position after the lapse of predetermined loading completion waiting time after the sheet member is loaded. 
   In a case where the pickup means placed in the evacuation position is placed into the pickup position right after it is detected that a sheet member is loaded on the tray, once a sheet member is loaded on the tray, the held sheet member cannot be removed from the tray because of the pickup means placed in the pickup position. However, since the pickup means is placed into the pickup position after the lapse of loading completion waiting time after it is detected that a sheet member is loaded on the tray, the pickup means is placed in the evacuation position during the loading completion waiting time, and therefore, the user can easily remove a sheet member from the tray. As a result, for example, when an undesired sheet member is loaded on the tray by mistake, the user can easily remove during loading completion waiting time, and it is possible to prevent that an undesired sheet member is taken out by the pickup means and processed. 
   Still further, in the invention it is preferable that the apparatus further comprises loading completion waiting time input means for inputting loading completion waiting time. 
   According to the invention, loading completion waiting time is inputted by the loading completion waiting time input means, so that the user can set loading completion waiting time depending on the ability of the user. 
   Still further, in the invention it is preferable that the apparatus further comprises take-out request input means for inputting a request for taking out a sheet member, and that the control means controls the pickup driving means so as to displace the pickup means into the evacuation position in a case where, after the pickup means is displaced from the evacuation position into the pickup position, a take-out request is not inputted after a lapse of preset request waiting time for waiting for input of a take-out request. 
   According to the invention, in the case where, after the pickup means is displaced from the evacuation position into the pickup position, a take-out request is not inputted after the lapse of preset request waiting time for waiting for input of the take-out request, the pickup means is displaced into the evacuation position. Thus, for example, the case where a take-out request is not inputted after the lapse of request waiting time after the pickup means is displaced into the pickup position is thought to be, for example, a case where an operation of taking out a sheet member by the pickup means is not performed and a case where a sheet member is added and loaded on the tray. Therefore, in this case, the pickup means is placed in the evacuation position, so that it is possible to easily and quickly remove and load a sheet member. 
   Still further, in the invention it is preferable that the apparatus further comprises request waiting time input means for inputting request waiting time. 
   According to the invention, request waiting time is inputted by the request waiting time input means, so that the user can set request waiting time depending on the ability of the user. 
   Still further, in the invention it is preferable that the apparatus further comprises feeding request input means for inputting a request for feeding a sheet member, and that when a feeding request is inputted, the control means controls the pickup driving means so as to displace the pickup means placed in the evacuation position into the pickup position, and after displacement into the pickup position, controls the pickup means so as to take out a sheet member placed in the take-out position. 
   According to the invention, when a feeding request is inputted by the feeding request input means, the pickup means is displaced from the evacuation position into the pickup position, and after that, controlled so as to take out a sheet member placed in the take-out position. Thus, the pickup means is placed in the evacuation position during the time between loading of a sheet member on the tray and input of a feeding request. Therefore, the pickup means is placed into the pickup means when the user inputs a feeding request after checking, for example, whether a loaded sheet member is a desired sheet member or not and whether a sheet member is in a predetermined holding state on the tray or not, so that a sheet member can be rapidly and certainly taken out by the pickup means. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other and further objects, features, and advantages of the invention will be more explicit from the following detailed description taken with reference to the drawings wherein: 
       FIG. 1  is a sectional view showing an image reading apparatus equipped with a sheet member feeding and conveying apparatus of an embodiment of the invention; 
       FIG. 2  is a block diagram showing an electrical configuration of the image reading apparatus; 
       FIG. 3  is a sectional view showing a section III of  FIG. 1  by enlarging; 
       FIG. 4  is a sectional view showing a section IV of  FIG. 1  by enlarging; 
       FIG. 5  is a flowchart showing a first procedure of controlling a tray and a pickup section in a running reading mode and a both-face reading mode of the image reading apparatus; 
       FIGS. 6A to 6D  are sectional views schematically showing the operation of a tray main body and the pickup section; and 
       FIG. 7  is a flowchart showing a second procedure of controlling the tray and the pickup section in the running reading mode and the both-face reading mode of the image reading apparatus. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Now referring to the drawings, preferred embodiments of the invention are described below. 
     FIG. 1  is a sectional view showing an image reading apparatus  2  equipped with a sheet member feeding and conveying apparatus  1  of an embodiment of the invention.  FIG. 2  is a block diagram showing an electrical configuration of the image reading apparatus  2 . In  FIG. 1 , thickness is partially omitted in order to make comprehension easy. The image reading apparatus  2  is an apparatus which optically reads an image formed on a document as a sheet member, converts to electric signals, and outputs as digital image data. The image reading apparatus  2 , when located on a horizontal plane, is capable of reading images formed on both faces of a document by a first reading unit  100  which is supported by a lower case  4  placed below an upper case  5  by which the sheet member feeding and conveying apparatus  1  is supported and a second reading unit  200  which is supported by the upper case  5  supporting the sheet member feeding and conveying apparatus  1 . 
   The sheet member feeding and conveying apparatus  1  comprises a tray  10 , a tray driving section  20 , a pickup section  30 , a first conveying path  50 , a second conveying path  51 , and a belt conveying section  70 . The tray driving section  20 , the pickup section  30 , the first conveying path  50 , and the belt conveying section  70  are supported by the upper case  5 . 
     FIG. 3  is a sectional view showing a section III of  FIG. 1  by enlarging. In  FIG. 3 , thickness is partially omitted in order to make comprehension easy. The tray  10  includes a tray main body  11  and a fixed tray portion  12  that is fixed on the upper case  5 . The tray main body  11  has a planate first holding face  13 , and the fixed tray portion  12  has a planate second holding face  14 . The first and second holding faces  13 ,  14  are placed so as to front upward when the image reading apparatus  2  is located on a horizontal plane. The tray main body  11  and the fixed tray portion  12  are connected to each other by a hinge portion  15  disposed to one end of the tray main body  11 , so as to be capable of angular displacement about a tray axial line L 10  stretched in parallel with the first and second holding faces  13 ,  14 . 
   The tray main body  11  is provided with a document detecting section  40  serving as sheet member detecting means. The document detecting section  40  has, for example, an operation piece  40   a  which is capable of appearing from the other end of the first holding face  13  of the tray main body  11  and a sensor main body which switches between on and off states in response to an appearing motion of the operation piece  40   a . The sensor main body may be realized by a photosensor. In a state where any external force does not act, the operation piece  40   a  protrudes more outwardly than the first holding face  13 , and at this moment, the sensor main body is in the off state. When a document is loaded on the tray main body  11  at least, the operation piece  40   a  is pressed by the document to retreat from the first holding face  13  and evacuated, and the sensor main body is brought to the on state at this moment. The document detecting section  40  can detect the presence of a document on the tray main body  11  by the switch between the on and off states of the sensor main body, and when detecting that a document is held on the tray main body  11 , gives a document detection signal which represents that a document is held, to a control section  45  described later. 
   The tray driving section  20  serving as tray driving means includes a tray driving motor  21 , a first gear  22 , a second gear  23 , and a driving plate  24 . The tray driving motor  21  is realized by a stepping motor, controlled when a pulse signal is given by the control section  45  serving as control means, and driven to rotate about a rotation driving axial line L 21  stretched in parallel with the tray axial line L 10 . A pinion gear  25  is securely disposed to an output shaft of the tray driving motor  21 , and rotates about the rotation driving axial line L 21  together with the output shaft. 
   The first gear  22  is realized by, for example, a spur gear, supported so as to be rotatable about an axial line which is parallel with the rotation driving axial line L 21 , and meshed with the pinion gear  25 . The second gear  23  is realized by, for example, a spur gear, supported so as to be rotatable about an axial line which is parallel with the rotation driving axial line L 21 , and meshed with the first gear  22 . The driving plate  24  is substantially planate, and supported so as to be capable of angular displacement about a plate axial line L 24  which is parallel with the rotation driving axial line L 21  and which passes one end of the driving plate  24 . To the one end of the driving plate  24 , a gear piece  26  that makes angular displacement about the plate axial line L 24  is disposed. The gear piece  26  is realized by, for example, a spur gear, and meshed with the second gear  23 . Therefore, a rotation driving force outputted from the output shaft of the tray driving motor  21  is transmitted to the driving plate  24  via the first gear  23  and the second gear  24 , and the driving plate  24  makes angular displacement about the plate axial line L 24  by the rotation driving force. 
   The driving plate  24  is placed so that the other end of the driving plate  24  makes line contact with a rib  16  formed on the bottom portion of the tray main body  11  at all times. Thus, regarding the tray main body  11 , the one end of the tray main body  11  is supported to the fixed tray portion  12  via the hinge portion  15 , and the other end of the tray main body  11  is supported to the other end of the driving plate  24  via the rib. Therefore, when the driving plate  24  makes angular displacement about the plate axial line L 24 , the tray main body  11  makes angular displacement about the tray axial line L 10 . 
   Since the other end of the driving plate  24  and the rib  16  of the tray main body  11  are line contact with each other, it is possible to make a friction force due to contact smaller and cause the tray main body  11  to make angular displacement more smoothly than in the case of being face contact. Moreover, since the other end of the driving plate  24  and the rib  16  of the tray main body  11  are line contact with each other, it is possible to make local wear at a contact point less and make the durability of the tray main body  11  and the driving plate  24  higher than in the case of being point contact. Besides, by disposing the rib  16  that protrudes from the rear face of the first holding face  13 , it is possible to increase the strength of the tray main body  11 . 
   Below the tray main body  11  of the upper case  5 , a convex portion  17  stretched in parallel with the tray axial line L 10  and protruding toward the tray main body  11  is disposed. When the tray main body  11  is placed in a maximum amount holding position Q 1 , which is a position the farthest from the pickup section  30  described later, the tray main body  11  abuts on the convex portion  17 . Since the tray main body  11  is placed in the maximum amount holding position Q 1  when documents of the maximum holding amount of the tray  10  are held, when the tray main body  11  abuts on the convex portion  17 , the tray main body  11  can thereby hold the maximum holding amount of documents in a stable manner at least. In this embodiment, the maximum amount of documents that can be held on the tray  10  is approximately 200 in a case where a document is 62 g/m 2  by basis weight. 
   The pickup section  30  serving as pickup means includes an attracting roller  31 , a separation roller  32 , and a connecting arm portion  33 . The attracting roller  31  is a column-shaped roller whose peripheral portion is made of a resin such as rubber and whose axial line is an attracting roller axial line L 31 , and is supported by the connecting arm portion  33  so as to be rotatable about the attracting roller axial line L 31  in a manner that the attracting roller axial line L 31  and the tray axial line L 10  are parallel with each other. The separation roller  32  is a column-shaped roller whose peripheral portion is made of a resin such as rubber and whose axial line is a separation roller axial line L 32 , and is supported by the connecting arm portion  33  so as to be rotatable about the separation roller axial line L 32  in a manner that the separation roller axial line L 32  and the tray axial line L 10  are parallel with each other. 
   The attracting roller  31  rotates about the attracting roller axial line L 31  when a rotation driving force outputted from an output shaft of a pickup driving motor  81  (refer to  FIG. 2 ) realized by, for example, a stepping motor is transmitted thereto via a power transmission mechanism (not shown). The separation roller  32  rotates about the separation roller axial line L 32  when a rotation driving force outputted from the output shaft of the pickup driving motor  81  is transmitted thereto via a power transmission mechanism (not shown) Moreover, the separation roller  32  is placed so as to front, from above, the most upstream portion in a first conveying direction A 1  described later of the first conveying path  50 . The connecting arm portion  33  is supported more upwardly than the tray main body  11  in the upper case  5  so as to be capable of angular displacement about the separation roller axial line L 32 . With respect to the pickup section  30 , the tray main body  11  is capable of angular displacement in directions close to and away from the pickup section  30 , and driven by the tray driving section  20  so as to make angular displacement in the directions close to and away from the pickup section  30 . 
   Further, in a feeding state of feeding a document held on the tray  10  to the first conveying path  50 , the pickup section  30  is capable of displacement between a pickup position P 1  where the attracting roller  31  abuts on a document closest to the pickup section  30  placed in a take-out position and is capable of taking out documents abutting on the attracting roller  31  one by one and an evacuation position P 2  evacuated from the pickup position P 1 , more specifically, evacuated more upwardly than the pickup position P 1  and within the upper case  5 . Since the pickup section  30  does not exist in a space region fronting the tray  10  from above when the pickup section  30  is placed in the evacuation position P 2 , the user can easily place and load documents from above the tray  10  when loading documents, especially, loading a lot of documents on the tray  10 . 
   A solenoid  34  is disposed to the upper case  5  near the pickup section  30 . Moreover, a coil spring  35  is disposed so as to connect the upper case  5  near the pickup section  30  and the connecting arm portion  33  of the pickup section  30 . In a solenoid off state where an electric current is not passed through the solenoid  34 , the coil spring  35  applies a spring force for stably placing the pickup section  30  in the evacuation position P 2  to the pickup section  30 . When brought into a solenoid on state by the passage of an electric current, the solenoid  34  gives the pickup section  30  a driving force for resisting the spring force of the coil spring  35  and stably placing the pickup section  30  in the pickup position P 1 . By such pickup driving means including the solenoid  34  and the coil spring  35 , the pickup section  30  can make angular displacement about the separation roller axial line L 32 , between the pickup position P 1  and the evacuation position P 2 . 
   A tray detecting section  41  is realized by, for example, a reflective photoelectric switch having a light emitting portion and a light receiving portion, and detects the position of the tray main body  11 . The tray detecting section  41  is placed in a position where, when the tray main body  11  is placed in a waiting position which is a position where a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position, light emitted from the light emitting portion of the tray detecting section  41  is reflected by the tray main body  11  and the reflected light enters the light receiving portion of the tray detecting section  41 . The tray detecting section  41  is in an on state when light enters the light receiving portion of the tray detecting section  41 , and in an off state when light does not enter the light receiving portion. Thus, the tray detecting section  41  is capable of detecting by the switch between on and off whether the tray main body  11  is placed in the waiting position or not, and gives the control section  45  a waiting position placement signal which represents that the tray main body  11  is placed in the waiting position. 
   In a waiting state of waiting for loading of documents on the tray  10 , a waiting position closer to the pickup section  30  than a maximum amount holding position Q 1 , which is the position of the tray main body  11  at the time when the maximum holding amount of documents are held on the tray  10 , is a waiting position Q 2  at the time when a few copy sheets of 62 g/m 2  by basis weight are held in this embodiment. The tray detecting section  41  is set so as to be in the on state when the tray main body  11  is placed in the waiting position Q 2  as described before. This is because the number of documents to be read that is set the most frequently is a few, and in response to the most frequently set amount of documents, the waiting position is set. Moreover, at this moment, the position of the tray main body  11  is slightly lower than a position closest to the pickup section  30 . The tray detecting section  41  is attached to the upper case  5  by, for example, the user. 
   A pickup detection section  42  is realized by, for example, a transmissive photoelectric switch which has a light emitting portion  42   a  and a light receiving portion  42   b  and in which the light emitting portion  42   a  and the light receiving portion  42   b  are placed apart so as to front each other, and detects the position of the pickup section  30 . When the pickup section  30  is placed in the pickup position P 1 , the pickup detecting section  42  is placed in a position where a protrusion piece  36  disposed to the connecting arm portion  33  of the pickup section  30  is placed between the light emitting portion  42   a  and the light receiving portion  42   b  of the pickup detecting section  42  and light emitted from the light emitting portion  42   a  is shut off by the protrusion piece  36  and does not enter the light receiving portion  42   b . The pickup detecting section  42  is in an off state when light enters the light receiving portion  42   b  of the pickup detecting section  42 , and in an on state when light does not enter the light receiving portion  42   b . Thus, the pickup detecting section  42  is capable of detecting by the switch between on and off whether the pickup section  30  is placed in the pickup position P 1  or not, and gives the control section  45  a pickup placement signal which represents that the pickup section  30  is placed in the pickup position P 1 . 
   As described above, the pickup position P 1  is a position where the attracting roller  31  of the pickup section  30  abuts on a document closest to the pickup section  30  held on the tray  10  placed in the take-out position. Therefore, detection whether the pickup section  30  is placed in the pickup position P 1  or not is equal to detection whether a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position or not. Thus, it is possible to detect whether the pickup section  30  is placed in the pickup position P 1  or not and whether a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position or not by the use of the only one pickup detecting section  42 , so that it is possible to simplify the constitution of the sheet member feeding and conveying apparatus  1  without the need for detecting means which independently detects whether a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position or not. 
   On the first conveying path  50  and the second conveying path  51 , a document taken out of the tray  10  by the pickup section  30  is conveyed. The first conveying path  50  is a curved conveying path where a document is reversed while being conveyed so that one face of the document conveyed in the first conveying direction A 1  which fronts upward when the document is held on the tray  10  fronts downward when the document is discharged from the first conveying path  50 . The upper case  5  is provided with a guide body  54  along the first conveying path  50 . 
   A separation auxiliary roller  52  is disposed so as to front the most upstream portion in the first conveying direction A 1  of the first conveying path  50 . The separation auxiliary roller  52  is a column-shaped roller whose axial line is parallel with the separation roller axial line L 32 , and supported to the upper case  5  so as to abut on the separation roller  32 . When a document taken out by the attracting roller  31  is caught between the separation roller  32  and the separation auxiliary roller  52 , and the separation roller  32  rotates, the document is conveyed on the first conveying path  50  in the first conveying direction A 1 . Moreover, the separation auxiliary roller  52  is provided with a torque limiter for limiting rotation about the axial line thereof. As a result, in a case where a plurality of documents are taken out by the attracting roller  31 , torque required for conveyance increases, whereby only the separation auxiliary roller  52  of the separation roller  32  and the separation auxiliary roller  52  stops rotating, and therefore, only a document touching the separation roller  32  in rotation is separated and conveyed on the first conveying path  50  in the first conveying direction A 1 . 
   On the downstream side in the first conveying direction A 1  from the separation roller  32  and the separation auxiliary roller  52  on the first conveying path  50 , a paper feed detecting section  53  is disposed so as to front the first conveying path  50 . The paper feed detecting section  53  has, for example, an operation piece  53   a  which is capable of appearing from the guide body  54  onto the first conveying path  50  on the downstream side in the first conveying direction A 1  from the separation roller  32  and the separation auxiliary roller  52 , and a sensor main body  53   b  which switches between on and off states in response to an appearing motion of the operation piece  53   a . The sensor main body  53   b  may be realized by a photosensor. 
   The operation piece  53   a  protrudes onto the first conveying path  50  more than the guide body  54  when any external force does not act thereon, and on this occasion, the sensor main body  53   b  is in the off state. When a document is conveyed to the downstream side in the first conveying direction A 1  from the separation roller  32  and the separation auxiliary roller  52 , the operation piece  53   a  is pressed by the document to retreat from the first conveying path  50  and evacuated more than the guide body  54 , and on this occasion, the sensor main body  53   b  is brought into the on state. By the switch between the on and off states of the sensor main body  53   b , the paper feed detecting section  53  is capable of detecting the presence of a document on the downstream side in the first conveying direction A 1  from the separation roller  32  and the separation auxiliary roller  52  on the first conveying path  50 . When detecting that a document exists on the downstream side in the first conveying direction A 1  from the separation roller  32  and the separation auxiliary roller  52  on the first conveying path  50 , the paper feed detecting section  53  gives the control section  45  described later a conveying path document detection signal which represents that a document exists on the downstream side in the first conveying direction A 1  from the separation roller  32  and the separation auxiliary roller  52  on the first conveying path  50 . The control section  45  can recognize the timing of conveying a document based on the conveying path document detection signal. 
   A first conveyance driving roller  55  and a first conveyance driven roller  56  are disposed so as to front the first conveying path  50  on the downstream side in the first conveying direction A 1  from the paper feed detecting section  53 , and furthermore, a second conveyance driving roller  57  and a second conveyance driven roller  58  are disposed so as to front the first conveying path  50  on the downstream side in the first conveying direction A 1  from the first conveyance driving roller  55  and the first conveyance driven roller  56 . The first conveyance driving roller  55 , the first conveyance driven roller  56 , the second conveyance driving roller  57 , and the second conveyance driven roller  58  are column-shaped rollers whose axial lines are parallel with the separation roller axial line L 32  and whose peripheral portions are made of a resin such as rubber, and supported by the upper case  5  so as to be rotatable about the axial lines thereof. 
   The first and second conveyance driving rollers  55 ,  57  rotate about the axial lines by a rotation driving force outputted from an output shaft of a conveying roller driving motor  82  (refer to  FIG. 2 ) realized by a stepping motor, for example. The first conveyance driven roller  56  abuts on the first conveyance driving roller  55 , and rotates driven by the rotation of the first conveyance driving roller  55 . Moreover, the second conveyance driven roller  58  abuts on the second conveyance driving roller  57 , and rotates driven by the rotation of the second conveyance driving roller  57 . A document is caught between the first conveyance driving roller  55  and the first conveyance driven roller  56 , and conveyed to the downstream side in the first conveying direction A 1  by the rotation of the first conveyance driving roller  55 . Moreover, a document is caught between the second conveyance driving roller  57  and the second conveyance driven roller  58 , and conveyed to the downstream side in the first conveying direction A 1  by the rotation of the second conveyance driving roller  57 . 
     FIG. 4  is a sectional view showing a section IV of  FIG. 1  by enlarging. In  FIG. 4 , thickness is partially omitted in order to make comprehension easy. The second conveying path  51  is a conveying path which is disposed so as to be connected to the most downstream portion in the first conveying direction A 1  of the first conveying path  50  and stretched horizontally when the image reading apparatus  1  is placed on a horizontal plane. A light-transmitting platen glass  60  stretched in the horizontal direction so as to front the second conveying path  50  from below is supported to the lower case  4 . The most downstream portion in the first conveying direction A 1  of the first conveying path  50  is slanted with respect to the second conveying path  51 , and an angle formed by the first conveying path  50  and the second conveying path  51  is set to 12 degrees, for example. 
   A belt conveying section  70  is disposed so as to front the upstream portion in the second conveying direction A 2  of the second conveying path  51  from above. The belt conveying section  70  includes a driving roller  71 , a driven roller  72 , a belt  73 , an auxiliary roller  74 , and a spring member  75 . The driving roller  71  is a column-shaped roller whose axial line is a driving roller axial line L 71  stretched in parallel with the separation roller axial line L 32  and at least whose peripheral portion is made of a resin such as polyacetal, supported by the upper case  5  so as to be rotatable about the driving roller axial line L 31 , and rotated about the driving roller axial line L 31  by a rotation driving force outputted from an output shaft of a conveying belt driving motor  83  (refer to  FIG. 2 ) realized by a stepping motor, for example. 
   The driven roller  72  is a column-shaped roller whose axial line is a driven roller axial line L 72  stretched in parallel with the driving roller axial line L 71 , whose outer diameter is equal to the outer diameter of the driving roller  71  in size and at least whose peripheral portion is made of a resin such as polyacetal, and supported by the upper case  5  so as to be rotatable about the driven roller axial line L 72 . Moreover, a spring force is applied to the driven roller  72  in a direction away from the driving roller  71  by the spring member  75  realized by, for example, a coil spring. Furthermore, the driven roller  72  is placed on the upstream side in the second conveying direction A 2  from the driving roller  71 . 
   The belt  73  is realized by an endless belt made of, for example, urethane rubber, and wound around between the driving roller  71  and the driven roller  72 . The thickness of the belt  73  is about 0.5 mm or more and 1.5 mm or less, for example. Since a spring force is given by the spring member  75  to the driven roller  72  in the direction away from the driving roller  71  as described before, a tensile force in the perimeter direction is generated on the belt  73 . This tensile force generates, between the belt  73  and the driving roller  71  and between the belt  73  and the driven roller  72 , resistance in the radial directions of the respective rollers  71 ,  72 . Besides, since the resistance generates static friction forces between the belt  73  and the driving roller  71  and between the belt  73  and the driven roller  72 , the belt  73  is moved between the driving roller  71  and the driven roller  72  by the rotation of the driving roller  71 , and the driven roller  72  is rotated by the movement of the belt  73 . In addition, because of the tensile force generated in the perimeter direction, portions of the belt  73  between the driving roller  71  and the driven roller  72  are tightly stretched like flat plates. 
   Further, since the driving roller  71  is placed on the downstream side in the second conveying direction A 2  from the driven roller  72 , the driving roller  71  rotates so as to pull the belt  73 , a document makes face contact with a surface fronting the second conveying path  51  of a portion of the belt  73  pulled by a friction force generated between the belt  73  and the driving roller  71 , and the document is conveyed in the second conveying direction A 2  by the movement of the belt  73 , it is possible to make a speed of conveying a document constant as compared with a case of conveying in a manner that a document makes face contact with a surface of a loosened portion of the belt  73 . 
   The size of the outer diameter of the driving roller  71  is set in consideration of a friction force generated between the belt  73  and the driving roller. Moreover, the size of the outer diameter of the driven roller  72  is set in consideration of a contact state thereof with the belt  73 , transmission of a rotation force from the belt  73 , and so on. In this embodiment, the sizes of the outer diameters of the driving roller  71  and the driven roller  72  are set to about 25 mm, for example. For the purpose of increasing static friction forces between the belt  73  and the driving roller  71  and between the belt  73  and the driven roller  72 , the outer peripheral faces of the driving roller  71  and the driven roller  72  may be coated with a polymeric material having a large friction coefficient. 
   On a face to become the rear side of a face fronting the second conveying path  51  of the belt  73  fronting the second conveying path  51 , a plurality of (two in  FIG. 4 ) auxiliary rollers  74  are supported while abutting. The auxiliary roller  74  is a column-shaped roller whose axial line is stretched in parallel with the driving roller axial line L 71  and outer diameter is smaller in size than the outer diameters of the driving roller  71  and the driven roller  72 . The auxiliary roller  74  is supported by the upper case  5  so as to be rotatable about the axial line. The number and interval in the alignment direction of the auxiliary rollers  74  are set depending on the interval between the driving roller  71  and the driven roller  72  so as not to be separated from at least the platen glass  60  when the belt  73  moves. The number of the auxiliary rollers  74  is, for example, a few to ten-odd, and the interval between the adjacent auxiliary rollers  74  is set to 50 to 120 mm, for example. The support by the auxiliary rollers  74  enables the face of the belt  73  fronting the second conveying path  51  between the driving roller  71  and the driven roller  72  to certainly keep a planate shape even when the belt  73  moves. 
   A document conveyed to the second conveying path  51  is caught between the belt  73  fronting the second conveying path  51  and the platen glass  60 . A friction coefficient between the document and the belt  73  is sufficiently larger than a friction coefficient between the document and the platen glass  60 . Therefore, the document certainly makes face contact with the belt  73  fronting the second conveying path  51  moved in the second conveying direction A 2  by the rotation of the driving roller  71 , and is conveyed to the downstream side in the second conveying direction A 2  by a friction force between the document and the belt  73 . 
   Since the most downstream portion in the first conveying direction A 1  of the first conveying path  50  is slanted with respect to the second conveying path  51  as described before, a document is curved as shown in  FIG. 4  when the document passes through a connection region  59  between the first conveying path  50  and the second conveying path  51 . By the curvature of a document in the connection region  59 , the document makes contact with the guide section  54  fronting the first conveying path  50 , and gives resistance R in a direction perpendicular to the first conveying direction A 1 , more specifically, a direction heading outward in the curvature radial direction of the connection region  59 . Because of a reaction force of the resistance R, a friction force in the opposite direction to the first conveying direction A 1  is applied to the document. When the document is separated from the guide section  54  while the most upstream portion of the document in the first conveying direction A 1  passes through the most downstream portion in the first conveying direction A 1  in the first conveying direction A 1  of the first conveying path  50 , and a friction force between the document and the guide section  54  is lost, the magnitude of an external force acting on the document in a direction of conveying the document changes radically. 
   Since the driven roller  72  is placed on the upstream side in the second conveying direction A 2  more than the driving roller  71  and given a spring force by the spring member  75  in the direction away from the driving roller  71  as described before, the spring member  75  can absorb a radical change of the external force acting on the document in the direction of conveying the document, that is, acting in the second conveying direction A 2 . Moreover, because of face contact between a document and the belt  73 , a friction force is large as compared with that in a case where, for example, a document makes line contact with a cylindrical roller, so that it is possible to make a speed of conveying a document constant against a radical change of the external force acting on a document. 
   The interval between the driving roller axial line L 71  of the driving roller  71  and the driven roller axial line L 72  of the driven roller  72  is set so that the contact area of a document and the belt  73  becomes an area which enables obtaining a friction force against a change of the external force acting on a document. 
   The first reading unit  100  has a first reading position F 1  on the downstream side in the second conveying direction A 2  from the belt conveying section  70 . The second reading unit  200  has a second reading position F 2  on the downstream side in the second conveying direction A 2  apart from the first reading position F 1 . The interval between the first reading position F 1  and the second reading position F 2  is 15 mm, for example. 
   A document mat  6  is disposed to the upper case  50  in a position fronting the platen glass  60  except the belt conveying section  70 , the second reading unit  200 , a discharge driving roller  62  and a paper discharge detecting section  63 . The document mat  6  is a substantially planate mat which has elasticity at least in the thickness direction, and is capable of abutting on the platen glass  60  so as to make face contact. 
   The first reading unit  100  includes a first scanning portion  101 , a second scanning portion  102 , an imaging lens  103  and a charge coupled apparatus (abbreviated to CCD)  104 , and is supported by the lower case  4  under the platen glass  60 . 
   The first scanning portion  101  includes a light source  105  and a first reflection mirror  106 . The light source  105  is realized by, for example, a halogen lamp, and irradiates a document existing on the second conveying path  51  with light via the platen glass  60 . The first reflection mirror  106  reflects light emitted from the light source  105  and reflected on a document into a predetermined direction. In this embodiment, in a state where the image reading apparatus  2  is placed on a horizontal plane, a reflection face of the first reflection mirror  106  is placed at a slant of 45 degrees with respect to the horizontal plane so as to front upward in the vertical direction and front the horizontal direction, and reflects light from a document entering from above in the substantially vertical direction into the horizontal direction. 
   The second scanning portion  102  includes a second reflection mirror  107  and a third reflection mirror  108 . The second reflection mirror  107  reflects light from the first reflection mirror  106  of the first scanning portion  101  toward the third reflection mirror  108 . The third reflection mirror  108  is placed below the second reflection mirror  107 , and reflects light from the second reflection mirror  107  into a predetermined direction. In this embodiment, a reflection face of the second reflection mirror  107  is placed at a slant of 45 degrees with respect to the horizontal plane so as to front the third reflection mirror  108  and the first reflection mirror  106 , and reflects light from the first reflection mirror  106  entering in the substantially horizontal direction, downward in the vertical direction. Moreover, a reflection face of the third reflection mirror  108  is placed at a slant of 45 degrees with respect to the horizontal plane so as to front a direction parallel with a direction opposite to the second conveying direction A 2 , and reflects light from the second reflection mirror  107  entering from above in the substantially vertical direction, into a direction parallel with a direction opposite to the second conveying direction A 2 . 
   The imaging lens  103  is realized by, for example, a convex lens, and concentrates light from the third reflection mirror  108  of the second scanning portion  102  to the CCD  104 . The CCD  104  converts light concentrated by the imaging lens  103  to analog electric signals by photoelectric conversion and outputs it. The imaging lens  103  and the CCD  104  are fixed to the lower case  4 . 
   The first and second scanning portions  101 ,  102  are supported to the lower case  4  so as to be capable of displacement in the second conveying direction A 2  along the platen glass  60 . The first and second scanning portions  101 ,  102  are driven to be displaced in the second conveying direction A 2  along the platen glass  60  by scanning portion driving means (not shown) including, for example, a stepping motor and a wire. 
   In a still reading mode of reading an image formed on a document in the state of keeping the document still in the image reading apparatus  2 , a document is placed on the platen glass  60  fronting the document mat  6 , and caught between the document mat  6  and the platen glass  60 . At this moment, the first scanning portion  101  is placed in a first scanning position Ps 1  fronting a portion closest to the belt conveying section  70  of the document mat  6 . 
   When the user places a document so that a face desired to be read fronts the platen glass  60  fronting the document mat  6 , and operates the operation section  47  to input a still document reading instruction which represents reading of a document in the still reading mode, the first reading unit  100  makes the light source  105  of the first scanning portion  101  emit light, and reads an image formed on the document while being displaced in a first scanning direction B 1 , which is a direction away from the belt conveying direction  70 . The first scanning portion  101  is capable of displacement from the first scanning position Ps 1  to a second scanning position Ps 2  fronting a portion the farthest away from the belt conveying section  70  of the document mat  6 . In order to make the length of an optical path from a document to the CCD  104  of the first reading unit  100  constant, the scanning portion driving means is controlled so that a second displacement speed U, which is a displacement speed of the second scanning portion  102  at the time of reading a document, has the same direction as a first displacement speed V, which is a displacement speed of the first scanning portion  101  at the time of reading a document, and so that the magnitude thereof is one half of that of the first displacement speed V (U=V/2). 
   After reading all images formed on a document, the first reading unit  100  turns off the light source  105 , and is displaced in the opposite direction to the first scanning direction B 1  and placed in the first scanning position Ps 1 . Such control of the first reading unit  100  is executed by the control section  45 . 
   When the image reading apparatus  2  is not used, the first scanning portion  101  rests in a home position, which is one of the first scanning position Ps 1 , a third scanning position Ps 3 , and a middle position between the first scanning position Ps 1  and the third scanning position Ps 3 . 
   The first reading unit  100  is capable of photoelectric conversion of light reflected on a document in an image pickup device, accumulation of the charges in the charge coupled device, and generation of an image based on the amount of the charges accumulated during a predetermined time. In this manner, by reading a document placed on the platen glass  60  and generating image data repeatedly at predetermined times, the first reading unit  100  can obtain a two-dimensional image identical to an image formed on a face fronting the first reading unit  100  of the document while displacing the first scanning portion  101  in the first scanning direction B 1 . Analog signals which represent generated image data are converted to digital signals in an image processing section  48 , and given to the control section  45 . 
   The second reading unit  200  is realized by a contact image sensor (abbreviated to CIS), and supported by the upper case  5  so as to front the second conveying path  51 . The second reading unit  200  includes a light emitting portion  201 , a light guiding portion  202  and an image sensor  203 . The light emitting portion  201  is constituted in a manner that, for example, a plurality of light emitting diodes (abbreviated to LED) which emit light to a document to be conveyed in the second conveying direction A 2  of the second conveying path  51  and read are placed in parallel in a direction parallel with the driving roller axial line L 71  of the driving roller  71 , that is, a direction perpendicular to the second conveying direction A 2 . The light guiding portion  202  is constituted by, for example, a lens array which concentrates light emitted from the light emitting portion  201  to a document and reflected in the second reading position F 2 , to the image sensor  203 . The image sensor  203  includes the image pickup device having a plurality of light receiving elements aligned straightly and a charge coupled device, and receives light reflected on a document and perform photoelectric conversion of the received light. 
   The second reading unit  200  is capable of photoelectric conversion of light reflected on a document in the image pickup device, accumulation of the charges in the charge coupled device, and generation of an image based on the amount of the charges accumulated during a predetermined time. In this manner, by reading a document caught between the second reading unit and the platen glass  60 , and generating image data repeatedly at predetermined times, the second reading unit  200  is capable of obtaining a two-dimensional image identical to an image formed on a face fronting the second reading unit  200  of a document conveyed in the second conveying direction A 2 . Analog signals which represent generated image data are converted to digital signals in the image processing section  48 , and given to the control section  45 . 
   A discharge driving roller  61  and a discharge driven roller  62  are disposed so as to front the second conveying path  51  on the downstream side in the second conveying direction A 2  from the second reading unit  200 . The discharge driving roller  61  and the discharge driven roller  62  are column-shaped rollers whose axial lines are stretched in parallel with the attracting roller axial line L 31  and whose peripheral portions are made of a resin such as rubber. The discharge driving roller  61  is supported by the upper case  5  so as to be rotatable about the axial line thereof. The discharge driven roller  62  is supported by the lower case  4  so as to be rotatable about the axial line thereof. 
   The discharge driving roller  61  is rotated about the axial line by a rotation driving force outputted from an output shaft of a discharge roller driving motor  84  (refer to  FIG. 2 ) realized by, for example, a stepping motor. The discharge driven roller  62  abuts on the discharge driving roller  61 , and rotates driven by the rotation of the discharge driving roller  61 . A document read by the first and second reading units  100 ,  200  is caught between the discharge driving roller  61  and the discharge driven roller  62 , and conveyed to the downstream side in the second conveying direction A 2  by the rotation of the discharge driving roller  61 . 
   A paper discharge detecting section  63  is disposed so as to front the most downstream portion in the second conveying direction A 2  of the second conveying path  51 , which is on the downstream side in the second conveying direction A 2  from the discharge driving roller  61  and the discharge driven roller  62 . The paper discharge detecting section  63  has, for example, an operation piece  63   a  capable of appearing on the most downstream portion in the second conveying direction A 2  of the second conveying path  51  and a sensor main body  63   b  which switches between on and off states in response to the appearing motion of the operation piece  63   a . The sensor main body  63   b  may be realized by a photosensor. 
   In a state where any external force does not act, the operation piece  63   a  protrudes to the second conveying path  51 , and on this occasion, the sensor main body  63   b  is in the off state. When a document is conveyed to the most downstream portion in the second conveying direction A 2  of the second conveying path  51  by the discharge driving roller  61  and the discharge driven roller  62 , the operation piece  63   a  is pressed by the document to retreat from the second conveying path  51  and evacuated, and on this occasion, the sensor main body  63   b  is brought into the on state. By the switch between the on and off states of the sensor main body  63   b , the paper discharge detecting section  63  can detect that a document is flown down through the most downstream portion in the second conveying direction A 2  of the second conveying path  51  and discharged to a paper discharge tray  64 , and when detecting that the document is discharged to the paper discharge tray  64 , gives the control section  45  described later a paper discharge detection signal which represents that the document is discharged to the paper discharge tray  64 . A document passed through the paper discharge detecting section  63  is discharged to the paper discharge tray  64 . 
   The upper case  5  and the lower case  4  are connected by, for example, a hinge so that the upper case  5  is capable of angular displacement with respect to the lower case  4  and the document mat  6  and the belt conveying section  70  of the upper case  5  and the platen glass  60  of the lower case  4  are capable of being close to and away from each other. 
   The image reading apparatus  2  further comprises the control section  45 , a storing section  46 , the operating section  47 , and the image processing section  48 . The control section  45  is realized by, for example, a processor such as a central processing unit (abbreviated to CPU), and controls at least the tray driving motor  21 , the solenoid  34 , the pickup driving motor  81 , the conveying roller driving motor  82 , the conveying belt driving motor  83 , the discharge roller driving motor  84 , the first reading unit  100 , and the second reading unit  200 , thereby totally controlling the image reading apparatus  2 . 
   The storing section  46  is realized by, for example, a volatile memory such as a random access memory (abbreviated to RAM), a nonvolatile memory such as a read only memory (abbreviated to ROM), and a large-capacity magnetic storing medium such as a hard disk drive (abbreviated to HDD). In the storing section  46 , a program for controlling the image reading apparatus  2  which the control section can execute is previously stored. Moreover, in the storing section  46 , image data of an image formed on a document read by the first and second reading units  100 ,  200  is temporarily stored. Furthermore, in the storing section  46 , various kinds of set data such as a waiting position, loading completion waiting time and request waiting time which are inputted from the operating section  47  are stored. 
   The operating section  47  that serves as waiting position inputting means, loading completion waiting time inputting means, take-out request inputting means, request waiting time inputting means and feeding request inputting means is realized by, for example, an inputting apparatus such as a keyboard and a touch panel and a display apparatus such as a liquid crystal display apparatus. The user of the image reading apparatus  2  can input a waiting position, loading completion waiting time, request waiting time, a still document reading instruction, a running document reading instruction, a both-face document reading instruction and the like by operating the operating section  47  to input. In this embodiment, a take-out request includes a still document reading instruction, a running document reading instruction and a both-face document reading instruction. 
   The image processing section  48  includes an analog/digital converter and a processor, for example. The image processing section  48  converts analog signals which represent image data from the first and second reading units  100 ,  200  into digital signals, applies various kinds of image processing to digitalized image data, and gives to the control section  45 . 
   In the image reading apparatus  2 , in a running reading mode of loading a document on the tray  10 , conveying the document on the first and second conveying paths  50 ,  51  and reading an image formed on a face fronting the platen glass  60  of the document on the second conveying path  51 , and in a both-face reading mode of loading a document on the tray  10 , conveying the document on the first and second conveying paths  50 ,  51  and reading images formed on both faces of the document, the first scanning portion  101  of the first reading unit  100  is placed in the third scanning position Ps 3  fronting the first reading position F 1 . 
   When the user loads a document on the tray  10  so that a face desired to be read (may be referred to as “an image forming face” hereafter) fronts above, and operates the operating section  47  to input a running document reading instruction which represents reading of a document in the running reading mode, the control section  45  controls the first reading unit  100  based on the running document reading instruction to place the first scanning portion  101  in the third scanning position Ps 3 . Subsequently, in accordance with procedures shown in FIGS.  5 ,  7  described later, the control section  45  controls the tray driving section  20  and the pickup section  30  to take out the document from the tray  10 . 
   Subsequently, the control section  45  controls the conveying roller driving motor  82  to rotate the first and second conveyance driving rollers  55 ,  57  based on a conveying path document detection signal from the paper feed detecting section  53  and convey the document taken out of the tray  10  so as to flow down on the first conveying path  50  in the first conveying direction A 1 . At this moment, the document is reversed by being conveyed on the first conveying path  50 , and on the second conveying path  51 , the image forming face fronts below, that is, the platen glass  60 . Subsequently, the control section  45  controls the conveying belt driving motor  83  to rotate the driving roller  71  of the belt conveying section  70 , move the belt  73  in the second conveying direction A 2  and convey the document so as to flow down on the second conveying path  51  in the second conveying direction A 2 . At this moment, the document passes through the first reading position F 1 . After that, the control section  45  controls the discharge roller driving motor  82  to rotate the discharge driving roller  61  and discharge the document to the paper discharge tray  64 . 
   Further, when the document passes through the first reading position F 1 , the control section  45  controls the first reading unit  100  to cause the light source  105  of the first scanning portion  101  to emit light and irradiate the image forming face of the document passing through the first reading position F 1  with the light. Reflection light from the document enters the CCD  104  via the respective reflection mirrors  106  to  108  of the first scanning portion  101  and the second scanning portion  102  and the imaging lens  103 . Thus, the first reading unit  100  reads an image formed on an image forming face of a document. 
   Further, when the user loads a document on the tray  10  and operates the operating section  47  to input a both-face document reading instruction which represents reading of a document in the both-face reading mode, the control section  45  controls the first reading unit  100  to place the first scanning portion  101  in the third scanning position Ps 3  based on the both-face document reading instruction. Subsequently, the control section  45  controls the tray driving section  20  and the pickup section  30  to take a document out of the tray  10  in accordance with the procedures shown in the flowcharts of  FIGS. 5 ,  7 . 
   Subsequently, based on a conveying path document detection signal from the paper feed detecting section  53 , the control section  45  controls the conveying roller driving motor  82  to rotate the first and second conveyance driving rollers  55 ,  57  and convey the document taken out of the tray  10  so as to flow down in the first conveying direction A 1  on the first conveying path  50 . At this moment, the document is reversed by being conveyed on the first conveying path  50 , and on the second conveying path  51 , a face fronting above when the document is held on the tray  10  (may be referred to as “a first face” hereafter) fronts below, that is, the platen glass  60  and a face fronting below when the document is held on the tray  10  (may be referred to as “a second face” hereafter) fronts above, that is, the belt conveying section  70 . Subsequently, the control section  45  controls the conveying belt driving motor  83  to rotate the driving roller  71  of the belt conveying section  70 , move the belt  73  in the second conveying direction A 2  and convey the document so as to flow down in the second conveying direction A 2  on the second conveying path  51 . At this moment, the document passes through the first reading position F 1  and the second reading position F 2 . After that, the control section  45  controls the discharge roller driving motor  82  to rotate the discharge driving roller  61  and discharge the document to the paper discharge tray  64 . 
   Further, when the document passes through the first reading position F 1 , the control section  45  controls the first reading unit  100  to cause the light source  105  of the first scanning portion  101  to emit light and irradiate the first face of the document passing through the first reading position F 1  with the light. Reflection light from the document enters the CCD  104  via the respective reflection mirrors  106  to  108  of the first scanning portion  101  and the second scanning portion  102  and the imaging lens  103 . Thus, the first reading unit  100  reads an image formed on a first face of a document. 
   Further, when the document passes through the second reading position F 2 , the control section  45  controls the second reading unit  200  to cause the light emitting portion  201  to emit light and irradiate the second face of the document passing through the second reading position F 2  with the light. Reflection light from the document enters the image sensor  203  via the light guiding portion  202 . Thus, the second reading unit  200  reads an image formed on a second face of a document. In this manner, in the both-face reading mode, it is possible by conveying the document on the first and second conveying paths  50 ,  51  only once to read images formed on both faces of a document by the use of the first reading unit  100  and the second reading unit  200 . 
   Since the first reading position F 1  of the first reading unit  100  and the second reading position F 2  of the second reading unit  200  locate a predetermined interval apart, it is possible to space an optical axis L 1  of reflection light from a first face of a document in the first reading position F 1  and an optical axis L 2  of reflection light from a second face of a document in the second reading position F 2 . As a result, it is possible to prevent that light emitted from the light source  105  of the first scanning portion  101  of the first reading unit  100  and passed through a document enters the image sensor  203  of the second reading unit  200  and the second reading unit  200  reads an image formed on a first face of a document, and that light emitted from the light emitting portion  202  of the second reading unit  200  and passed through a document enters the CCD  104  of the first reading unit  100  and the first reading unit  100  reads an image formed on a second face of a document, and it is possible to accurately read images formed on a first face and a second face of a document. 
     FIG. 5  is a flowchart showing a first procedure of controlling the tray  10  and the pickup section  30  in the running reading mode and the both-face reading mode of the image reading apparatus  2 .  FIGS. 6A to 6D  are sectional views schematically showing motions of the tray main body  11  and the pickup section  30 . The first control procedure starts at step s 0 , and goes to step s 1 . At step s 1 , when the user of the image reading apparatus  2  performs an input operation of the operating section  47 , power is applied to the image reading apparatus  2 , and the procedure goes to step s 2 . At step s 2 , the control section  45  determines whether a waiting position placement signal from the tray detecting section  41  exists or not, and the procedure goes to step s 3  when it is determined that a waiting position placement signal does not exist, whereas the procedure goes to step s 4  when it is determined that a waiting position placement signal exists. 
   When it is determined at step s 2  that a waiting position placement signal does not exist, that is, the tray main body  11  is not placed in the waiting position Q 2 , and the procedure goes to step s 3 , the control section  45  controls the tray driving motor  21  to cause the tray main body  11  to make angular displacement at step s 3 , and the procedure goes back to step s 2 . The tray driving motor  21  is controlled based on a waiting position placement signal from the tray detecting section  41 , and by repeatedly executing step s 1  and step s 2 , the tray main body  11  is placed in the waiting position Q 2 , and the tray main body  11  is kept still in the waiting position Q 2  until the procedure goes to step s 8  described later. Moreover, until the procedure goes to step s 6  described later, the control section  45  does not pass an electric current through the solenoid  34 , and the pickup section  30  is placed in the evacuation position P 2  as shown in  FIG. 6A . Therefore, until the procedure goes to step s 6 , the user can easily load a document on the tray  10  and easily remove a document held on the tray  10 . 
   When it is determined at step s 2  that a waiting position placement signal exists, that is, the tray main body  11  is placed in the waiting position Q 2  as shown in  FIG. 6A , and the procedure goes to step s 4 , the control section  45  determines at step s 4  whether a document detection signal from the document detecting section  40  exists or not, and the procedure goes to step s 5  when it is determined that a document detection signal exists. Determination of the presence of a document detection signal at step s 4  is continued until it is determined that a document detection signal exists. 
   When it is determined at step s 4  that a document detection signal exists, that is, a document is loaded and held on the tray  10 , and the procedure goes to step s 5 , the control section  45  determines at step s 5  whether either a running document reading instruction or a both-face document reading instruction (these instructions may be referred to as “reading instructions” hereafter) is inputted from the operating section  47 , and the procedure goes to step s 6  when it is determined that a reading instruction is inputted. Determination at step s 5  whether a reading instruction is inputted or not is continued until it is determined that a reading instruction is inputted. 
   When it is determined at step s 5  that a reading instruction is inputted, and the procedure goes to step s 6 , the control section  45  passes an electric current through the solenoid  34  and causes the attracting roller  31  of the pickup section  30  to abut on a document held on the tray  10  as shown in  FIG. 6B  at step s 6 , and the procedure goes to step s 7 . 
   At step s 7 , the control section  45  determines whether a pickup placement signal from the pickup detecting section  42  exists or not, and the procedure goes to step s 8  when it is determined that a pickup placement signal does not exist, whereas the procedure goes to step s 9  when it is determined that a pickup placement signal exists. 
   When it is determined at step s 7  that a pickup placement signal does not exist, that is, the pickup section  30  is not placed in the pickup position P 1  as shown in  FIG. 6C , and the procedure goes to step s 8 , the control section  45  controls the tray driving motor  21  to cause the tray main body  11  to make angular displacement at step s 8 , and the procedure goes back to step s 7 . Control of the tray driving motor  21  is executed based on a pickup placement signal from the pickup detecting section  42 , and by repeatedly executing step s 7  and step s 8 , the pickup section  30  is placed in the pickup position P 1 . 
   When it is determined at step s 7  that a pickup placement signal exists, that is, the pickup section  30  is placed in the pickup position P 1  as shown in  FIG. 6D , and the procedure goes to step s 9 , the control section  45  controls the pickup driving motor  81  and the conveyance roller driving motor  82  to take out documents held on the tray  10  one by one sequentially from a document closest to the pickup section  30  placed in the take-out position and convey to the first conveying path  50  at step s 9 , and the procedure goes to step s 10 . 
   At step s 10 , the control section  45  determines whether a document detection signal from the document detecting section  40  exists or not, and the procedure goes back to step s 7  when a document detection signal exists, whereas when it is determined that a document detection signal does not exist, that is, all the documents are taken out of the tray  10  and the tray  10  does not hold any document, the procedure goes to step s 11 , and the control section  45  controls the tray driving section  20  to place the tray main body  11  in the waiting position Q 2 , and all the procedural steps end. 
     FIG. 7  is a flowchart showing a second procedure of controlling the tray  10  and the pickup section  30  in the running reading mode and the both-face reading mode of the image reading apparatus  2 . Here,  FIG. 6  will be also referred to. The second control procedure starts at step t 0 , and the procedure goes to step t 1 . 
   At step t 1 , when the user of the image reading apparatus  2  performs an input operation of the operating section  47 , power is applied to the image reading apparatus  2 , and the procedure goes to step t 2 . At step t 2 , the control section  45  determines whether a waiting position placement signal from the tray detecting section  41  exists or not, and the procedure goes to step t 3  when it is determined that a waiting position placement signal does not exist, whereas the procedure goes to step t 4  when it is determined that a waiting position placement signal exists. 
   When it is determined at step t 2  that a waiting position placement signal does not exist, that is, the tray main body  11  is not placed in the waiting position Q 2 , and the procedure goes to step t 3 , the control section  45  controls the tray driving motor  21  to cause the tray main body  11  to make angular displacement at step s 3 , and the procedure goes back to step t 2 . The tray driving motor  21  is controlled based on a waiting position placement signal from the tray detecting section  41 , and by repeatedly executing step t 1  and step t 2 , the tray main body  11  is placed in the waiting position Q 2 , and the tray main body  11  is kept still in the waiting position Q 2  until the procedure goes to step t 8  described later. Moreover, until the procedure goes to step t 6  described later, the control section  45  does not pass an electric current through the solenoid  34 , and the pickup section  30  is placed in the evacuation position P 2  as shown in  FIG. 6A . Therefore, until the procedure goes to step t 6 , the user can easily load a document on the tray  10  and easily remove a document held on the tray  10 . 
   When it is determined at step t 2  that a waiting position placement signal exists, that is, the tray main body  11  is placed in the waiting position Q 2  as shown in  FIG. 6A , and the procedure goes to step t 4 , the control section  45  determines at step t 4  whether a document detection signal from the document detecting section  40  exists or not, and the procedure goes to step t 5  when it is determined that a document detection signal exists. Determination of the presence of a document detection signal at step t 4  is continued until it is determined that a document detection signal exists. 
   When it is determined at step t 4  that a document detection signal exists, that is, a document is loaded and held on the tray  10 , and the procedure goes to step t 5 , the control section  45  waits for loading completion waiting time at step t 5 , which is for waiting for loading of documents and completion of loading and which is preset and stored in the storing section  46 , and the procedure goes to step t 6 . 
   At step t 6 , as shown in  FIG. 6B , the control section  45  passes an electric current through the solenoid  34  so as to place the pickup section  30  placed in the evacuation position P 2  into the pickup section P 1 , and causes the attracting roller  31  of the pickup section  30  to abut on a document held on the tray  10 , and the procedure goes to step t 7 . At step t 7 , the control section  45  determines whether a pickup placement signal from the pickup detecting section  42  exists or not, and the procedure goes to step t 8  when it is determined that a pickup placement signal does not exist, whereas the procedure goes to step t 9  when it is determined that a pickup placement signal exists. 
   When it is determined at step t 7  that a pickup placement signal does not exist, that is, the pickup section  30  is not placed in the pickup position P 1  as shown in  FIG. 6C , and the procedure goes to step t 8 , the control section  45  controls the tray driving motor  21  to cause the tray main body  11  to make angular displacement at step t 8 , and the procedure goes back to step t 7 . The tray driving motor  21  is controlled based on a pickup placement signal from the pickup detecting section  42 , and step s 7  and step s 8  are repeatedly executed so as to place the pickup section  30  in the pickup position P 1 . 
   When it is determined at step t 7  that a pickup placement signal exists, that is, the pickup section  30  is placed in the pickup position P 1  as shown in  FIG. 6D , and the procedure goes to step t 9 , the control section  45  determines at step t 9  whether a reading instruction is inputted from the operating section  47  or not, and the procedure goes to step t 10  when it is determined that a reading instruction is inputted, whereas the procedure goes to step t 12  when it is determined that a reading instruction is not inputted. 
   When it is determined at step t 9  that a reading instruction is inputted from the operating section  47 , and the procedure goes to step t 10 , the control section  45  controls the pickup driving motor  81  and the conveyance roller driving motor  82  to take out documents held on the tray  10  one by one sequentially from a document closest to the pickup section  30  placed in the take-out position and convey to the first conveying path  50  at step t 10 , and the procedure goes to step t 11 . 
   At step t 11 , the control section  45  determines whether a document detection signal from the document detecting section  40  exists or not, and the procedure goes to step t 17  when it is determined that a document detection signal exists, whereas the procedure goes to step t 19  when it is determined that a document detection signal does not exist, that is, all the documents are taken out of the tray  10  and the tray  10  does not hold any document, and the control section  45  controls the tray driving section  20  to place the tray main body  11  in the waiting position Q 2 , and all the procedural steps end. 
   When it is determined at step t 9  that either the running document reading instruction or the both-face document reading instruction is not inputted from the operating section  47 , and the procedure goes to step t 12 , the control section  45  determines at step t 12  whether request waiting time, which is for waiting for input of either the running document reading instruction or the both-face document reading instruction and which is preset and stored in the storing section  46 , is elapsed from passing of an electric current through the solenoid  34 , and the procedure goes to step t 13  when it is determined that the request waiting time is elapsed, whereas the procedure goes back to step t 9  when it is determined that the request waiting time is not elapsed. 
   When it is determined at step t 12  that the request waiting time is elapsed from passing of an electric current through the solenoid  34 , and the procedure goes to step t 13 , the control section  45  stops passing an electric current through the solenoid  34  and places the pickup section  30  in the evacuation position P 2  at step t 13 , and the procedure goes to step t 14 . 
   At step t 14 , it is determined whether a document detection signal from the document detecting section  40  exists or not, and the procedure goes to step t 15  when it is determined that a document detection signal exists, whereas when it is determined that a document detection signal does not exist, that is, any document is not held on the tray  10 , the procedure goes to step t 19 , and the control section  45  controls the tray driving section  20  to place the tray main body  11  in the waiting position Q 2 , and all the procedural steps end. 
   At step t 15 , the control section  45  determines whether a reading instruction is inputted from the operating section  47  or not, and the procedure goes to step t 16  when it is determined that a reading instruction is inputted, whereas the procedure goes back to step t 14  when it is determined that a reading instruction is not inputted. 
   When it is determined at step t 15  that a reading instruction is inputted from the operating section  47 , and the procedure goes to step t 16 , as shown in  FIG. 6B , the control section  45  passes an electric current through the solenoid  34 , and causes the attracting roller  31  of the pickup section  30  to abut on a document held on the tray  10  at step t 16 , and the procedure goes to step t 17 . 
   At step t 17 , the control section  45  determines whether a pickup placement signal from the pickup detecting section  42  exists or not, and the procedure goes back to step t 10  when it is determined that a pickup placement signal exists, whereas the procedure goes to step t 18  when it is determined that a pickup placement signal does not exist. 
   When it is determined at step t 17  that a pickup placement signal does not exist, that is, the pickup section  30  is not placed in the pickup position P 1  as shown in  FIG. 6C , and the procedure goes to step t 18 , the control section  45  controls the tray driving motor  21  to cause the tray main body  11  to make angular displacement at step t 18 , and the procedure goes back to step t 17 . The tray driving motor  21  is controlled based on a pickup placement signal from the pickup detecting section  42 , and step t 17  and step t 18  are repeatedly executed so as to place the pickup section  30  in the pickup position P 1 . 
   The loading completion waiting time is preset time for waiting for the user to load a document on the tray  10  and complete loading, and inputted from the operating section  47  and stored in the storing section  46 . As shown by steps t 4  to t 6  of  FIG. 7 , in a waiting state, when it is determined by the document detecting section  40  that a document is loaded on the tray  10 , the control section  45  passes an electric current through the solenoid  34  after a lapse of the loading completion waiting time so as to place the pickup section  30  placed in the evacuation position P 2  into the pickup position P 1 . 
   The loading completion waiting time can be freely set depending on the level of skill of the user to loading of a document onto the tray  10 . Moreover, the loading completion waiting time may be, for example, set for every user or set longer or shorter depending on a reading process, and selected by the user by an input operation of the operating section  47  at the time of using the image reading apparatus  2 . The loading completion waiting time is set to approximately 1 to 8 seconds, for example. By setting the loading completion waiting time, it is possible, before documents are loaded on the tray  10  and the attracting roller  31  of the pickup section  30  abuts on the documents held on the tray  10 , for example, to make an opportunity of adjusting the orientations of the documents held on the tray  10  and loading more documents on the tray  10 . Thus, it is possible to prevent a conveyance failure called a jam of documents in the first conveying path  50  resulting from a holding state failure of documents on the tray  10 , and easily load a lot of documents on the tray  10 . 
   The request waiting time is preset time for waiting for the user to input either the running document reading instruction or the both-face document reading instruction, and inputted from the operating section  47  and stored in the storing section  46 . As shown by steps t 9  and t 12  of  FIG. 7 , in a case where, after the pickup section  30  is displaced from the evacuation position P 2  to the pickup position P 1  and the attracting roller  31  abuts on a document, any reading instruction is not inputted after a lapse of the request waiting time, the control section  45  stops passing an electric current through the solenoid  34  so as to displace the pickup section  30  into the evacuation position P 2 . 
   The request waiting time can be freely set at a request of the user. Moreover, the request waiting time may be, for example, set and stored for every user or set longer or shorter depending on a reading process, and selected by the user by an input operation of the operating section  47  at the time of using the image reading apparatus  2 . The request waiting time is set to approximately 10 to 30 seconds, for example. As a result of setting the request waiting time, it can be thought that documents to be read are added or reading of documents is cancelled in a case where any reading instruction is not inputted after a lapse of the request waiting time after the attracting roller  31  of the pickup section  30  abuts on documents held on the tray  10 . Therefore, in this case, passing of an electric current through the solenoid  34  is stopped and the pickup section  30  is placed in the evacuation position P 2 , whereby the user can easily load documents on the tray  10  and easily remove documents from the tray  10 . 
   As described above, according to the sheet member feeding and conveying apparatus  1  of this embodiment, by the tray driving section  20  controlled by the control section  45 , the tray main body  11  is, in the waiting state of waiting for loading of documents on the tray  10 , driven to be displaced in the waiting position Q 2  that is closer to the pickup section  30  than the position Q 1  at the time when the maximum holding amount of document are held on the tray  10 , and in the feeding state of feeding documents held on the tray  10 , driven to be displaced so that a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position. 
   Since the amount of displacement from the waiting position Q 2  closer to the pickup section  30  than the position Q 1  at the time when the maximum holding amount of documents are held on the tray  10  to a position where a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position is smaller than the amount of displacement from the waiting position Q 1  at the time when the maximum holding amount of documents are held on the tray  10  to a position where a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position, it is possible to shorten the duration from the time when a smaller amount than the maximum holding amount of the tray  10 , for example, a few documents are loaded on the tray  10  to the time when a document is taken out by the pickup section  30 . 
   More specifically, the time required for displacement of the tray main body  11  from the waiting position Q 1  at the time when the maximum holding amount of documents are held on the tray  10  to a position where a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position is one second. On the contrary, the time required for displacement of the tray main body  11  from the preset waiting position Q 2  closer to the pickup section  30  than the position Q 1  at the time when the maximum holding amount of document are held on the tray  10  to a position where a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position is shorter at least than the time required for displacement from the waiting position Q 1  at the time when the maximum holding amount of documents are held on the tray  10  to a position where a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position. Moreover, when the preset waiting position Q 2  and a position of the tray main body  11  where a document closest to the pickup section  30  held on the tray  10  is placed in the take-out position are almost the same, the time required for displacement of the tray  10  is almost zero second. Thus, the time required for displacement is largely shortened, and there is no need for displacement of the tray main body  11  in some cases of setting of the waiting position Q 2 . 
   Since the amount of handled documents is sufficiently smaller than the maximum holding amount of the tray  10  normally, for example, in the image reading apparatus  2  for reading an image formed on a document, it is possible to perform an image reading process at a high speed by equipping the image reading apparatus  2  with the sheet member feeding and conveying apparatus  1 . Moreover, in recent years, images are usually formed on both faces of a document in order to reduce the amount of paper to be used. Since, in this case, the amount of documents handled in the image reading apparatus  2  is further decreased, the image reading apparatus  2  equipped with the sheet member feeding and conveying apparatus  1  of this embodiment is considerably effective. 
   Further, according to the sheet member feeding and conveying apparatus  1  of this embodiment, the pickup section  30  is driven to be displaced between the pickup position P 1  and the evacuation position P 2  so as to be, in the feeding state, placed in the pickup position P 1  where a document placed in the take-out position can be taken out, and in the waiting state, placed in the evacuated position P 2  evacuated from the pickup position P 1 . When the pickup section  30  is placed in the evacuation position P 2 , the user can easily remove documents held on the tray  10  from the tray  10 . As a result, even when, for example, an undesired document is loaded on the tray  10  by mistake, the user can easily remove the document held on the tray  10  from the tray  10  and easily reload a desired document on the tray  10 , so that it is possible to prevent that an undesired document is taken out by the pickup section  30  and processed. 
   Moreover, according to the sheet member feeding and conveying apparatus  1  of this embodiment, in the waiting state, when it is detected by the document detecting section  40  that a document is loaded on the tray  10 , the pickup section  30  placed in the evacuation position P 2  is placed in the pickup position P 1  after a lapse of the loading completion waiting time from loading of a document. In a case where the pickup section  30  placed in the evacuation position P 2  is placed in the pickup position P 1  right after it is detected that a document is loaded on the tray  10 , once a document is loaded on the tray  10 , the held document cannot be removed from the tray  10  because of the pickup section  30  placed in the pickup position P 1 . However, since the pickup section  30  is placed in the pickup position P 1  after a lapse of the loading completion time after it is detected that a document is loaded on the tray  10 , the pickup section  30  is placed in the evacuation position P 2  during the loading completion waiting time, and therefore, the user can easily remove a document from the tray  10 . As a result, even when, for example, an undesired document is loaded on the tray  10  by mistake, the user can easily remove during the loading completion waiting time, and it is possible to prevent that an undesired document is taken out by the pickup section  30  and processed. 
   Further, according to the sheet member feeding and conveying apparatus  1  of this embodiment, the pickup section  30  is displaced from the evacuation position P 2  to the pickup position P 1  when a reading instruction is inputted by the operating section  47 , and thereafter, controlled so as to take out a document placed in the take-out position. As a result, since the pickup section  30  is placed in the evacuation position P 2  during the time between loading a document on the tray  10  and inputting a reading instruction, the user inputs a reading instruction after checking, for example, whether a loaded document is a desired document or not and whether a document is in a predetermined holding state on the tray  10  or not, whereby the pickup section  30  is placed in the pickup position P 1 . Therefore, it is possible to speedily and certainly take out a document by the pickup section  30 . 
   Although, in the image reading apparatus  2  of this embodiment, a waiting position is set by the user depending on the most frequently set number of documents to be read, and the tray detecting section  41  is mounted to the upper case  5  in a position where, when the tray main body  11  is placed in the waiting position, light emitted from the light transmitting portion of the tray detecting section  41  is reflected on the tray main body  11  and the reflected light enters the light receiving portion of the tray detecting section  41 , the waiting position Q 2  may be inputted by an input operation of the operating section  47  by the user previously and stored in the storing section  46 . 
   In this case, the position of the tray main body  11  may be detected by, for example, counting the number of pulses given to the tray driving motor  21  of the tray driving section  20 . Moreover, the position of the tray main body  11  may be detected by, for example, disposing a rotary encoder to the hinge section connecting the tray main body  11  and the fixed tray portion  12  and detecting an angle formed by the tray main body  11  and the fixed tray  12 . 
   As a result, in the waiting state, the tray main body  11  is driven by the tray driving section  20  to be displaced in the waiting position inputted by the operating section  47 , so that it is possible to certainly shorten the duration from the time when documents are loaded on the tray  10  to the time when the documents are taken out by the pickup section  30  by, for example, inputting a waiting position responsive to the amount of documents. 
   Further, the control section  45  may also function as waiting position determining means and determine a waiting position based on the amount of documents loaded on the tray  10  at the time of an take-out operation executed before. For example, a waiting position is set based on the average value of the numbers of documents in the past fifty to a hundred take-out operations. 
   As a result, a waiting position is determined based on the amount of documents loaded on the tray  10  at the time of a take-out operation executed before, it is possible to automatically determine a waiting position, and shorten the duration from the time when documents are loaded on the tray  10  to the time when the documents are taken out by the pickup section  30 . 
   Further, according to the sheet member feeding and conveying apparatus  1  and the image reading apparatus  2  of this embodiment, a document passes through the first reading position F 1  and the second reading position F 2  while at least one surface in the thickness direction of the document makes face contact with the belt  73  of the belt conveying section  70 , so that the contact area of a document and conveying means is large and a friction force between a document and conveying means is large as compared with those in a case where a document conveyed while making point contact and line contact with conveying means. As a result, for example, even when an undesired external force acts on a document in the second conveying direction A 2 , a large friction force between the document and the belt  73  resists the undesired external force, and the document can be stably conveyed in the second conveying direction A 2  and passed through the first and second reading positions F 1 , F 2 . Thus, since a document stably passes through the first and second reading positions F 1 , F 2 , the image reading apparatus  2  is capable of certainly executing a process of reading the document. 
   Further, according to the sheet member feeding and conveying apparatus  1  of this embodiment, the belt  73  is wound around between the driving roller  71  and the driven roller  72  disposed so as to be rotatable about the axial lines that are parallel with each other, the respective portions of the belt  73  between the rollers  71 ,  72  become planate, and can certainly make face contact with one surface in the thickness direction of a document. Moreover, since the belt  73  moves between the rollers  71 ,  72  by the rotation of the driving roller  71  driven to rotate by the conveyance belt driving motor  83 , moves between the rollers  71 ,  72  in the state of making face contact with one surface in the thickness direction of a document, and conveys the document, it is possible to successively move the belt  73  and successively move documents by, for example, controlling the conveyance belt driving motor  83  so as to successively rotate the driving roller  71 . Furthermore, for example, by controlling the conveyance belt driving motor  83  so as to cause the driving roller  71  to intermittently make angular displacement, it is possible to intermittently move the belt  73  and intermittently convey documents. Therefore, by controlling the conveyance belt driving motor  83  in accordance with a reading process, it is possible to easily change a mode of conveying documents. In addition, since a friction force between the belt  73  and a document depends on a friction coefficient of the belt  73 , it is possible to easily change a friction force between the belt  73  and a document by replacing the belt to one having a friction coefficient responsive to the kind of a document. 
   Further, according to the sheet member feeding and conveying apparatus  1  of this embodiment, the second conveying path  51 , which is a movement path of a document from the belt conveying section  70  to the first and second reading positions F 1 , F 2 , is stretched in a planate state, so that a document maintains a planate state without being curved when moving on the second conveying path  51 , and therefore, it is possible to prevent generation of a resistance force due to the curvature of a document, and convey a document more stably to pass through the first and second reading positions F 1 , F 2 . 
   Although, in the sheet member feeding and conveying apparatus  1  of this embodiment, the tray driving section  20  is constituted so as to transmit a rotation driving force from the tray driving motor  21  via the gears  22 ,  23  and so on, cause the driving plate  24  abutting on the other end of the tray main body  11  to make angular displacement and cause the tray main body  11  to make angular displacement, the constitution is not limited to this, and may be a constitution of, by the use of, for example, a wire and a pulley, displacing the whole tray  10  in the longitudinal direction and making it close to and away from the pickup section  30 . 
   Although, in the sheet member feeding and conveying apparatus  1  of this embodiment, documents to be read front the same platen glass  60  in the running reading and both-face reading modes and in the still reading mode, different platen glasses may be used in the running reading and both-face reading modes and in the still reading mode. Besides, a platen glass fronting the first reading position F 1  and a platen glass fronting the second reading position F 2  may be different bodies. 
   Further, although the light source of the first scanning portion  101  of the first reading unit  100  is a halogen lamp in the sheet member feeding and conveying apparatus  1  of this embodiment, it is not limited to this, and may be, for example, a xenon lamp and a fluorescent lamp. Moreover, although the second scanning portion  102  of the first reading unit  100  is constituted so as to include the two reflection mirrors  107 ,  108 , the constitution is not limited to this, and a unit of a reduced reading optical system or a unmagnified reading optical system in which at least a CCD, an imaging lens and a light source are integrated may be displaced at the same speed as the first displacement speed V of the first scanning portion  101 . 
   Further, although the column-shaped separation auxiliary roller  52  is disposed so as to front the most upstream portion in the first conveying direction A 1  of the first conveying path  50  in the sheet member feeding and conveying apparatus  1  of this embodiment, it is not limited to this and a planate pad whose surface has a large friction coefficient may be placed so as to front the most upstream portion in the first conveying direction A 1  of the first conveying path  50 , whereby a document is caught between the separation roller  32  and the pad, and when the separation roller  32  is rotated, only a document making contact with the separation roller  32  is separated and conveyed toward the first conveying direction A 1  on the first conveying path  50 . 
   Further, although the first conveying path is bent and stretched curvedly in the sheet member feeding and conveying apparatus  1  and the image reading apparatus  2  of this embodiment, it may be stretched in a planate state in accordance with the placement position of the tray  10 . 
   Further, in the sheet member feeding and conveying apparatus  1  of this embodiment, in a case where the amount of documents loaded on the tray  10  is more than the maximum holding amount, the pickup section  30  is not placed in the pickup position P 1  even when an electric current is passed through the solenoid  34 , the pickup section  30  is driven to be displaced from the evacuation position P 2  toward the pickup position P 1  and the tray driving section  20  is controlled. Therefore, the control section  45  may be constituted so as to, in this case, display a warning that the amount of documents on the tray  10  is more than the maximum holding amount on the operating section  47  and inform the user. 
   Although the driving roller  71  is a column-shaped roller at least whose peripheral portion is made of a resin such as polyacetal in the sheet member feeding and conveying apparatus  1  of this embodiment, it is not limited to this and, may be made of metal such as iron, stainless steel and aluminum, and the shape thereof may be a column-shaped gear on whose peripheral portion tooth grooves are incised. Moreover, although, regarding the driven roller  72 , at least peripheral portion is made of a resin such as polyacetal, it is not limited to this and, may be made of metal such as iron, stainless steel and aluminum. 
   Although the belt is an endless belt made of urethane rubber in the sheet member feeding and conveying apparatus  1  of this embodiment, it is not limited to this, and may be an endless belt made of neoprene, ethylene propylene diene rubber or acrylic nitrile butadiene rubber. 
   Further, although the sheet member feeding and conveying apparatus  1  of this embodiment is mounted on the image reading apparatus  2 , even when an apparatus including at least tray  10 , the tray driving section  20 , the pickup section  30 , the document detecting section  40 , the tray detecting section  41 , the pickup detecting section  42 , the control section  45 , the storing section  46  and the pickup driving motor  81  of the sheet member feeding and conveying apparatus  1  is mounted onto an image forming apparatus such as a printer, it is possible to obtain the same effect as in the aforementioned image reading apparatus  2 . 
   The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein.