Patent Publication Number: US-2011058234-A1

Title: Automatic paper feed device, image reading apparatus, and image forming apparatus

Description:
The present application is a continuation of U.S. patent application Ser. No. 11/523,887 filed Sep. 20, 2006, which claims priority from Japanese Patent Application No. 2005-271925 filed Sep. 20, 2005, the contents of which are incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an automatic paper feed device that automatically separates and transports stacked plural sheets of paper. The present invention also relates to an image reading apparatus and an image forming apparatus, both including the automatic paper feed device. 
     2. Description of the Related Art 
     JP-A-8-290835 describes an automatic paper feed device. This device uses a separation and transport mechanism to separate and transport multiple sheets of paper that are stacked and placed in a placement unit. 
     Paper is thin, and easily bends downwardly due to its own weight. Generally, as shown in  FIGS. 10 and 11 , paper is often placed in a placement unit  19   a  in a condition in which the paper is bent to form an arched shape that is downwardly convex so that the bending rigidity of the paper may be increased. This makes it difficult to bend the paper in a direction perpendicular to the bend of the arched shape. 
     However, when the paper is bent in an arched shape and placed in the placement unit, sometimes both ends in the width direction of the paper interfere with both longitudinal ends of a paper insertion opening  25   a  as shown in  FIG. 11 . In this case, a problem arises that the paper cannot be placed precisely in a predetermined place. 
     Although the above problem may be solved by sufficiently increasing the size of the paper insertion opening, another problem then arises. This problem is that the cover member, which forms the paper insertion opening and covers and protects a separation and transport mechanism, may then become unable to sufficiently cover the separation and transport mechanism. 
     SUMMARY OF THE INVENTION 
     According to one embodiment of the invention, an automatic paper feed device is provided, which includes (1) a placement unit in which paper is placed, (2) a separation and transport mechanism that separates paper placed in the placement unit and transports paper placed in the placement unit in a transport direction, and (3) a cover member that has a paper insertion opening in a nearly rectangular shape, the paper insertion opening having a longitudinal direction perpendicular to both a transport direction of the paper and a thickness direction of the paper. The paper insertion opening includes a first end opening portion, a second end opening portion, and a center opening portion. The center opening portion is located in a position corresponding to the separation and transport mechanism. The first end opening portion is disposed on one side of the center opening portion in the longitudinal direction of the paper insertion opening, and the second end opening portion is disposed on the other side of the center opening portion in the longitudinal direction of the paper insertion opening. The cover member covers the separation and transport mechanism. The paper insertion opening connects the placement unit with the separation and transport mechanism. The separation and transport mechanism is provided in a position corresponding to a nearly central location of the longitudinal direction of the paper insertion opening from the perspective of a head on view of the paper insertion opening. The first and second end opening portions are each larger in size than the central opening portion. 
     In accordance with another embodiment of the invention, an automatic paper feed device is provided, which includes (1) a placement unit in which paper is placed, (2) a separation and transport mechanism that separates paper placed in the placement unit and transports paper placed in the placement unit in a transport direction, and (3) a cover member that has a paper insertion opening. The paper insertion opening includes a first end opening portion, a second end opening portion, and a center opening portion. The paper insertion opening has a longitudinal direction perpendicular to both a transport direction of the paper and a thickness direction of the paper. The first end opening portion is disposed on one side of the center opening portion in the longitudinal direction of the paper insertion opening, and the second end opening portion is disposed on the other side of the center opening portion in the longitudinal direction of the paper insertion opening. The cover member covers the separation and transport mechanism. The first and second end opening portions are each larger in size than the central opening portion. 
     In accordance with yet another embodiment of the invention, an automatic paper feed device is provided, which includes (1) a placement unit in which paper is placed, (2) a transport mechanism, and (3) a paper insertion opening having a longitudinal direction perpendicular to both a transport direction of the paper and a thickness direction of the paper. The paper insertion opening includes a first end opening portion, a second end opening portion, and a center opening portion. The first end opening portion is disposed on one side of the center opening portion in the longitudinal direction and the second end opening portion is disposed on the other side of the center opening portion in the longitudinal direction. The first end opening portion is larger in size than the central opening portion. The second end opening portion is larger in size than the central opening portion. The transport mechanism transports paper from the placement unit, through the paper insertion opening, to a predetermined place. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the appearance of an image reading apparatus  1  according to a first embodiment. 
         FIG. 2  is a perspective view showing a state in which an original cover  3 , of the image reading apparatus  1 , is opened. 
         FIG. 3  shows an original insertion opening  25 , according to the first embodiment, seen from an insertion direction of the paper to be inserted into the original insertion opening  25 . 
         FIG. 4  shows part of a section of the image reading apparatus  1 . 
         FIG. 5  is a perspective view of the topside of the image reading apparatus  1 , 
         FIG. 6  is a block diagram showing the outline of an electrical configuration of the image reading apparatus  1 . 
         FIG. 7  is a flowchart showing an outline of a control flow from the time when a start button  55  is depressed to the time before a signal is output from the image pick-up device  11 . 
         FIG. 8  is a perspective view of the appearance of an image reading apparatus  1  according to a second embodiment of the invention. 
         FIG. 9  is a top view of the image reading apparatus according to the first embodiment of the invention. 
         FIG. 10  is a perspective view of an image reading apparatus according to the related art. 
         FIG. 11  is a perspective view of the image reading apparatus according to the related art. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Referring now to the drawings, the present invention will be described in detail on the basis of exemplary embodiments. 
     As shown in  FIG. 2 , an image reading window  7  (hereinafter, referred to as “stationary reading window  7 ”), for the stationary original reading function, and an image reading window  9  (hereinafter, referred to as “automatic reading window  9 ”), for the transport reading function, are provided in a main body unit  5 . An original cover  3  is pivotally mounted to the main body unit  5 . Stationary reading window  7  is closed by transparent platen  7   a,  and automatic reading window  9  is closed by transparent platen  9   a.  The transparent platens  7   a,    9   a  may be made of glass, an acrylic material, or the like. 
     In  FIG. 4 , an image pick-up device  11  receives light applied to, and reflected by, an original and generates an electrical signal based on the received light. The image reading apparatus  1  reads images by converting the images, including characters etc., contained in the original into electrical signals via the image pick-up device  11 . 
     The image pick-up device  11  is incorporated within the main body unit  5 , and is movable in the longitudinal direction of the main body unit  5  (in the horizontal direction in  FIG. 4 ). When the transport reading function is activated, the image pick-up device  11  is stops beneath the automatic reading window  9  and reads an image. On the other hand, when the stationary original reading function is activated, the sensor reads images while moving beneath the stationary reading window  7 . 
     In the embodiment, a CIS (Contact Image Sensor) is used as the image pick-up device  11 , and the longitudinal direction of the CIS (image pick-up device  11 ) extends in a direction perpendicular to the XY plane of  FIG. 4 . 
     A stationary original holder  13 , for holding an original against the stationary reading window  7 , is provided in the original cover  3  in a location facing the stationary reading window  7 . The stationary original holder  13  pivotally moves integrally with the original cover  3  relative to the stationary reading window  7 . 
     An automatic document feeder device (hereinafter, abbreviated as “ADF device”), having a separation and transport mechanism  15  that transports originals for reading to the automatic reading window  9 , is provided in the original cover  3  in a location corresponding to the automatic reading window  9 . The details of the ADF device will be described below. 
     In  FIG. 1  or  FIG. 2 , a base member  17  includes an original placement unit (original tray)  19 , in which originals for reading to he transported to the automatic reading window  9  are placed. Various kinds of rollers  15   a  to  15   d  (see  FIG. 4 ), which form the separation and transport mechanism  15 , are mounted to the base member  17 . The base member  17  is fixed to the original cover  3  by fixing means such as screws. 
     As shown in  FIG. 4 , the original placement unit  19  is tilted so that an original placed in the original placement unit  19  moves toward the suction roller  15   a  due to the original&#39;s own weight. 
     The original placement unit  19 , as shown in  FIG. 1 , includes a pair of original guides  21 . Each of the original guides  21  are brought into contact with a separate side of the original placed in the original placement unit  19  parallel with the transport direction of the original. The original guides  21  guide the transport of the original. The original guides  21  mechanically work in concert with each other, and are mounted to the original placement unit  19  so as to be displaced in the width direction of the original. Here, “the width direction of the original” refers to a direction perpendicular to both the transport direction of the original and the direction of the thickness of the original placed in the original placement unit  19 . The original guides  21  are not limited to being placed on the original placement unit  19 . For example, the original guides  21  may he placed on the base member  17 . 
     Further, as shown in  FIG. 4 , the separation and transport mechanism  15  includes a suction roller  15   a,  a separation roller  15   b,  a feed roller  15   c,  an eject roller  15   d,  pinch rollers  15   e  and  15   f,  and a guide face  15   g.  The suction roller  15   a  sucks originals placed in the original placement unit  19 . The separation roller  15   b  separates the suctioned originals one by one and send them to the feed roller  15   c.  The eject roller  15   d  ejects the originals to a paper eject tray  27 . 
     Pinch rollers  15   e,    15   f  press the transported original against the feed roller  15   c.  A guide face  15   g  guides the original transported from the original placement unit  19  toward the automatic reading window  9 . The guide face  15   g  turns the transportation direction of the original roughly 180°. 
     In addition, an automatic reading original holder  29  holds the transported original against the automatic reading window  9 , and is tilted relative to the automatic reading window  9  so as to be nearly parallel to the tangential direction of the contact point between the feed roller  15   c  and the pinch roller  151  Accordingly, the images of the original transported from the original placement unit  19  are read while the original passes through the gap between the automatic reading original holder  29  and the automatic reading window  9 . After the images of the original are read, the original is passed through an eject transport path  31  and ejected to the paper eject tray  27 . 
     The topside of the separation and transport mechanism  15  is covered by the cover member  23 , and, as shown in  FIG. 3 , the transport mechanism  15  is positioned corresponding to a nearly central part of the longitudinal direction of the original insertion opening  25 , as seen from the insertion direction of the original to be inserted into the original insertion opening  25 . 
     The cover member  23  is pivotally mounted to the base member  17 . Accordingly, if the original jams in the separation and transport mechanism  15 , it can be removed by opening the cover member  23 . 
     As shown in  FIG. 3 , the original insertion opening  25  is provided in the cover member  23 . The original insertion opening  25  allows originals to be transported from the original placement unit  19  to the separation and transport mechanism  15 . The original insertion opening  25  is formed in a nearly rectangular shape with the longitudinal direction perpendicular to both the transport direction of the original and the thickness direction of the original. 
     The original insertion opening  25  is symmetric with respect to a nearly central part of the original insertion opening  25  in the longitudinal direction. The original insertion opening  25  includes end opening portions A and central opening portion B. The central opening portion B is set in a nearly central part of the original insertion opening  25  in the longitudinal direction, and corresponds to the separation and transport mechanism  15  of the original insertion opening  25 . The end opening portions A are set on opposite sides of the central opening B. The size of the end opening portions A are larger than the size of the central opening portion B. In the embodiment shown in  FIG. 5 , the dimensions of the parts of the end opening portions A parallel to the thickness direction of the original are made larger than the dimension of the part of the central opening portion B parallel to the thickness direction of the original. 
     In order to smooth the transition between the central opening portion B and the end opening portions A, joint portions of the central opening portion B and the end opening portions A are tilted and enlarged. In addition at least part of each of the end opening portions A exists in a location corresponding to a position between the original guides  21 , even when the distance between the original guides  21  is at its smallest. 
     In  FIG. 6 , a CPU  51  is a processing unit that performs predetermined arithmetic processing according to a program stored in a ROM  53 . The ROM  53  is a storage means such as a flash memory or EEPROM capable of retaining the stored program even when the power supply is stopped. 
     A start switch (start button)  55 , for instructing the start of image reading, and an ADF (Automatic Document Feeder) original presence sensor  57 , for detecting whether or not an original is placed in the ADF device (original placement unit  19 ), are connected to the input side of the CPU  51 . An image pick-up device drive motor  59 , for moving the image pick-up device  11 , and a roller drive motor  61 , for rotating the various kinds of rollers  15   a  to  15   d  that form a part of the separation and transport mechanism  15 , are connected to the output side of the CPU  51 , An output signal of the image pick-up device  11  is stored in storage means such as a RAM  63 . 
       FIG. 7  is a flowchart showing the outline of a control flow from a time when the start button  55  is depressed to a time before a signal is output from the image pick-up device  11  and the control flow is executed in the CPU  51 . 
     When the start button  55  is depressed, the control flow shown in  FIG. 7  is activated. Based on the detection signal of the ADF original presence sensor  57  (S 1 ), either the stationary original reading function (S 2 ) or the transport reading function (S 3 ) is selected. 
     When the ADF original presence sensor  57  determines that an original is present in the original placement unit  19 , the CPU  51  selects the transport reading function. Contrary, when the ADF original presence sensor  57  determines that an original is absent in the original placement unit  19 , the CPU selects the stationary original reading function. 
     If the stationary original reading function is selected, the image pick-up device drive motor  59  is driven and images are read through the stationary reading window  7  (S 2 ). On the other hand, if the transport reading function is selected, the roller drive motor  61  is driven and images are continuously read through the automatic reading window  9  (S 3 ). 
     When an original is bent in an downwardly convex, arched shape, both ends thereof in the width direction of the original are displaced toward the thickness direction relative to a central part of the original in the width direction as, shown in  FIG. 11 . However, in the embodiment, the end opening portions A are larger than the central opening portion B, as shown in  FIG. 5 . Thus, the interference between the original and the original insertion opening  25  can be prevented from occurring even when the original is bent in an arched shape. 
     Furthermore, since the central opening portion B is smaller than the end opening portions A, the central opening portion B sufficiently covers the separation and transport mechanism  15 . Therefore, in the embodiment, the original can be placed in a predetermined place while the separation and transport mechanism  15  is sufficiently covered. 
     Moreover, when the original is bent in an arched shape, typically the original is continuously curved from the central part to the ends in the width direction. Thus, by smoothly changing the size of the opening portions from the central opening portion B to the end opening portions A, the original can be smoothly placed in a predetermined place. 
     In addition, even when the distance between the original guides  21  is at its smallest, the end opening portions A are set so that at least part of each of the end opening portions A exists in a location corresponding to a position between the original guides  21 . Thus, the original can be precisely placed in a predetermined place even when the distance between the original guides  21  is at its smallest. 
     Further, when the original is bent in an arched shape, typically the original is symmetrically bent. Thus, by making the original insertion opening  25  symmetric in its longitudinal direction with respect to a nearly central portion, the original can be more precisely placed in a predetermined place. 
     In the first embodiment, the end opening portions A are made larger than the central opening portion B by enlarging the end opening portions A in the height direction (in the direction in parallel with the thickness direction of the original). However, this is not the only way to make the end opening portions larger than the central opening portion. In a second embodiment, as shown in  FIGS. 8 and 9 , the end opening portions A are made larger than the central opening portion B with respect to the direction parallel to the transport direction of the paper. This is affected by curving the top of the original insertion opening such that the top of the central opening portion B extends in a direction opposite, and parallel, to the transport direction of the original, relative to the top of the end opening portions A. 
     As such, even when an original is bent in an arched shape, as shown in  FIG. 8 , the interference of both ends of the original, in the width direction, with the original insertion opening  25  (the cover member  23 ) can be prevented. Accordingly, the original can be placed precisely in a predetermined place while the separation and transport mechanism  15  is sufficiently covered. 
     In the above described embodiments, the original is bent in an arched shape, where both ends thereof in the width direction of the original are displaced toward the thickness direction relative to a central part of the original in the width direction, and placed in the placement unit  19 . The embodiments above describe the ends of the original being displaced toward the thickness direction of the original in roughly equal amounts. However, it may also be the case that one of the ends of the original is displaced in a greater amount than the other end. In such a case, it may be preferable that the paper insertion opening  25  is formed with one large opening portion and one small opening portion. Thus, interference between the original and the paper insertion opening  25  can be prevented from occurring even when the original is bent in such an arched shape and placed in the placement unit  19 . 
     An automatic paper feed device according to an aspect of the invention includes a placement unit, in which paper is placed, and a cover member. The cover member communicates with the placement unit and a separation and transport mechanism. The cover member has a paper insertion opening in a nearly rectangular shape with a longitudinal direction perpendicular to both a transport direction of the paper and a thickness direction of the paper. The paper insertion opening has a center opening portion, which corresponds to the separation and transport mechanism, and two end opening portions, which correspond to the two horizontal ends of the paper insertion opening. Both end opening portions have larger vertical dimensions (the thickness direction of the paper) than the vertical dimension of the center opening portion. 
     The cover member also covers the separation and transport mechanism. The separation and transport mechanism is provided in a position corresponding to a nearly central part of the paper insertion opening in the longitudinal direction, as seen from an insertion direction of the paper to be inserted into the paper insertion opening. 
     When the paper is bent in a downwardly convex, arched shape, both ends in the width direction of the paper are displaced relative to the central part in the width direction as shown in  FIG. 11 . However, since the end opening portions are larger than the central opening portion, the interference between the paper and the paper insertion opening can be prevented from occurring even when the paper is bent in an arched shape. The difference in size between the end opening portions and the central opening portion also allows for the central opening portion to sufficiently cover the separation and transport mechanism. Therefore, the paper can be placed precisely in a predetermined place while the separation and transport mechanism is sufficiently covered. 
     In addition, both end opening portions of the paper insertion opening have larger horizontal dimensions, in the transport direction of the paper, than that of the center opening portion. Further, the size of the opening portions may change smoothly from the central opening portion to the end opening portions. 
     In another embodiment, a pair of paper guides, that arc movable in the longitudinal direction of the paper insertion opening, are provided in the paper placement unit. The paper guides are brought into contact with the sides of the paper placed in the paper placement unit, thereby guiding the transport of the paper. At least part of each of the end opening portions exists in a location corresponding to a position between the pair of paper guides, even when the distance between the pair of paper guides is at its smallest. Thereby, the paper can be placed precisely in a predetermined place even when the distance between the pair of paper guides is at its smallest. 
     Further, when the paper is bent in an arched shape, it is generally symmetrically bent. Therefore, in another embodiment, the paper insertion opening is symmetric in the longitudinal direction of the paper insertion opening, with respect to the central part of the paper insertion opening. 
     According to another embodiment, an image reading apparatus, having an image pick-up device that generates an electrical signal based on received light, is presented. The image reading apparatus includes a reading window, for image reading, and the above described automatic paper feed device, for transporting paper placed in the placement unit to the image reading window. As such, the paper can be precisely placed in a predetermined place in the image reading apparatus. 
     According to yet another embodiment, an image forming apparatus is presented. The image forming apparatus includes an image forming unit, for forming an image on a medium, and the above described automatic paper feed device, for transporting paper placed in the placement unit to the image forming unit. As such, the paper can be precisely placed in a predetermined place in the image forming apparatus. 
     The described embodiments are image reading apparatuses. The embodiments have a transport reading function, for reading images contained in originals while the originals are being transported, and a stationary original reading function, for reading images contained originals that are stationary. These embodiments contain automatic paper feed devices. 
     In the above described embodiments the invention is applied to an image reading apparatus having a transport reading function and a stationary original reading function. However, the invention is not so limited. The invention may also be applied to an image reading apparatus having the transport reading function and not the stationary original reading function. In addition, the invention may be applied to an image reading apparatus integrated with an image forming apparatus, such as an inject printer or a laser printer. In fact, the current invention may be applied to any apparatus in which an image reading apparatus would be useful, such as a facsimile machine, a copy machine, or the like. 
     Also, in the above described embodiments the invention is applied to an automatic paper feed device that feeds originals to a reading unit of an image reading apparatus. However, the invention is not so limited. The invention may also be applied to an automatic paper feed device that feeds paper to an image forming unit of an image forming apparatus. 
     In addition, in the above described embodiments the CIS is used as the image pick-up device  11 . However, the invention is not so limited. For example, the invention may also use a CCD (Charge-Coupled Device). 
     Further, the invention should not be construed to be limited to only the two shapes of the original insertion opening  25  as described above. 
     Moreover, in the above described embodiments the end opening portions A and the central opening portion B are smoothly and continuously formed. However, the invention is not so limited to only that shape. 
     While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the inventions as defined in the following claims.