Document transport device

Abstract

To enable a document to be appropriately taken into a device main body.SOLUTION: The present invention provides a document transport device including transport means for transporting documents one by one from a document stack that is a bundle of a plurality of documents, and a document stopper for arranging a leading edge of the document stack, in which the document stopper is configured to be movable between a first position in which it blocks at least a portion of a transport path for the documents and a second position in which it opens at least a portion of the transport path, and when a weight of the document stack does not satisfy a standard, the document stopper moves from the first position to the second position.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a document transport device, and more particularly to a document feeder. [Background technology]

[0002] Among document transport devices that transport documents on which images have been formed, such as document feeders installed in printers and scanners, there are some that make it easier to sort the document stack in the order of transport by aligning the leading edge of the document stack with a document stopper when placing the document stack (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-101905 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the configuration of Patent Document 1, the document stopper is retracted when the documents are transported, so that the documents are transported in a bundle, which may cause so-called double feeding.

[0005] An exemplary object of the present invention is to enable a document to be appropriately loaded into the device body. [Means for solving the problem]

[0006] One aspect of the present invention relates to a document transport device, a conveying means for conveying documents one by one from a document stack that is a bundle of a plurality of documents; a document stopper for arranging the leading edge of the document stack; The document stopper is a first position that blocks at least a portion of the document transport path; a second position in which the conveying path is at least partially opened; and when the weight of the document stack does not satisfy a standard, the document stack is moved from the first position to the second position. It is characterized by: [Effects of the Invention]

[0007] According to the present invention, it is possible to appropriately take in the document into the device main body. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic side view showing an example of the configuration of the document feeding device according to the embodiment. [Figure 2] FIG. 2 is a block diagram showing an example of a system configuration of a document feeding device. [Figure 3] FIG. 2 is a perspective view illustrating the internal structure of the document feeding device. [Figure 4] FIG. 2 is an exploded perspective view illustrating a part of the internal structure of the document feeding device. [Figure 5] FIG. 2 is a side view of the internal structure of the document feeder. [Figure 6] FIG. 2 is a side view of the internal structure of the document feeder. [Figure 7A] FIG. 2 is a side view of the internal structure of the document feeder. [Figure 7B] FIG. 2 is a side view of the internal structure of the document feeder. [Figure 7C] FIG. 2 is a side view of the internal structure of the document feeder. [Figure 8A] FIG. 2 is a side view of the internal structure of the document feeder. [Figure 8B] FIG. 2 is a side view of the internal structure of the document feeder. [Figure 8C] FIG. 2 is a side view of the internal structure of the document feeder. [Figure 8D] FIG. 2 is a side view of the internal structure of the document feeder. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Furthermore, the same reference numerals are used for the same or similar components, and redundant explanations will be omitted.

[0010] The following embodiment will be described using a document feeder as an example of a document transport device according to the present invention.

[0011] <Overall configuration of the document feeder> FIG. 1 is a schematic side view showing an example of the configuration of a document feeder 1 according to an embodiment. The document feeder 1 is equipped with an image reading function (scanner function) for reading an image of a document Sh. The document feeder 1 includes a housing 10 that houses the various elements described below, a loading tray 13 on which a document Sh to be image-read can be placed, and a discharge tray 12 onto which the document Sh is discharged after image reading. The housing 10 is provided with an intake port 14 for taking in the document Sh from the loading tray 13 and a discharge port 11 for discharging the document Sh to the discharge tray 12.

[0012] When there are multiple documents Sh to be discharged, they are stacked on the loading tray 13, taken into the housing 10 in order, and after the images are read, they are stacked in order on the discharge tray 12. These trays can be arranged so that the upstream side in the conveying direction D0 from taking in the documents Sh to discharging them is positioned higher and the downstream side is positioned lower. The loading tray 13 and the discharge tray 12 may be referred to as a paper feed tray and a paper discharge tray, respectively, or may be referred to as a stacking section or the like instead of a tray.

[0013] The original Sh is a sheet-like member (e.g., paper) having an image formed on at least one side thereof. The concept of an image includes visible objects such as letters, symbols, figures, and photographs, as well as blank spaces that may be formed between or around them. The original Sh may be expressed as a sheet. The original feeding device 1 may also be expressed as a sheet conveying device. The document feeder 1 may have the above-mentioned scanner function and may additionally or alternatively have other functions such as a printer function or a facsimile function, and the scanner function may be a main function or an auxiliary function. Therefore, the document feeder 1 may be, for example, a multifunction peripheral (MFP), and can be interpreted as an electrical device in a broad sense.

[0014] The document feeder 1 further includes a transport mechanism 15, a reading unit 16, a pick arm unit 17, drive sources 18a and 18b, and drive transmission units 19a and 19b within the housing 10. Known electric motors can be used for the drive sources 18a and 18b.

[0015] The transport mechanism 15 is configured to form a transport path T for the document Sh from the loading tray 13 to the discharge tray 12, and in this embodiment includes a paper feed roller 151, a separation roller 153, a transport roller 159a, and a discharge roller 159b.

[0016] Near the intake port 14, the paper feed roller 151 forms a nip with the separation roller 153, thereby sandwiching and transporting the original Sh. During this time, if there are two or more sheets of original Sh being transported, the separation roller 153 separates them, preventing two or more sheets of original Sh from being transported (so-called double feeding).

[0017] The power of the drive source 18a is transmitted to the paper feed roller 151 via the drive transmission unit 19a, and the paper feed roller 151 rotates in the direction D1. The paper feed roller 151 has a built-in one-way clutch. As a result, for example, when the transport speed of the document Sh by the transport roller 159a is higher than the peripheral speed of the paper feed roller 151, the paper feed roller 151 rotates at the transport speed of the document Sh (it rotates along with the document Sh).

[0018] The separation roller 153, details of which will be described later (see FIG. 4(b)), is rotatably held by the separation unit 152, and together with the paper feed roller 151, clamps the document Sh taken in through the inlet 14. The separation roller 153 has a built-in torque limiter. The separation roller 153 rotates in direction D2 based on the power of the drive source 18a, and when a torque greater than a reference value is applied, the separation roller 153 will spin freely due to the torque limiter, and will rotate in direction D2'. In this way, when multiple documents Sh are taken in through the inlet 14, one of them on the paper feed roller 151 side will be transported appropriately, and the other documents Sh will be returned to the loading tray 13 without being transported. Here, a relatively soft material such as sponge may be used for at least the surface of the separation roller 153. Therefore, when the stack of documents Sh (hereinafter, sometimes referred to as "document stack Sh") comes into contact with the separation roller 153, the surface of the separation roller 153 is pressed, causing the surface to curve, for example. This increases the contact area between the separation roller 153 and the document stack Sh, making it difficult for the document stack Sh to slip on the surface, thereby enabling the separation to be performed appropriately.

[0019] A pair of transport rollers 159a are provided on the upstream side of the reading unit 16, one of which serves as a drive roller and the other as a driven roller to sandwich the document Sh and transport it towards the reading unit 16. A pair of discharge rollers 159b are provided on the downstream side of the reading unit 16, one of which serves as a drive roller and the other as a driven roller to sandwich the document Sh and transport it towards the paper discharge tray 12. These drive rollers 159a and 159b are rotated by the power of the drive source 18b transmitted via the drive transmission unit 19b.

[0020] A pair of reading units 16 are provided between rollers 159a and 159b on both sides of the transport path T (sandwiching the transport path T), one of which reads an image on one side (e.g., the front side) of the document Sh, and the other of which reads an image on the other side (e.g., the back side) of the document Sh. A contact image sensor can typically be used for the reading unit 16, but other known imaging devices constituted by a CCD / CMOS image sensor may also be used.

[0021] <System configuration> 2 is a block diagram showing an example of the system configuration of the document feeding device 1. The document feeding device 1 includes a sensor group 21, an operation input unit 22, and a control unit 23. The sensor group 21 includes a document stacking sensor unit 21a, a double feed detection sensor unit 21b, a first document detection sensor unit 21c, and a second document detection sensor unit 21d, and each sensor is disposed at a corresponding position on the transport path T.

[0022] The document loading sensor unit 21a is disposed upstream of the paper feed roller 151. The document loading sensor unit 21a uses, for example, a lever, a sensor, etc. (see FIG. 3), and for example, when the document Sh comes into contact with the lever, the lever rotates, and the rotation is detected by the sensor, thereby outputting a predetermined detection signal.

[0023] The multi-feed detection sensor unit 21b is disposed downstream of the separation roller 153, and detects the occurrence of a multi-feed and outputs a predetermined detection signal. The multi-feed detection sensor unit 21b uses, for example, an ultrasonic sensor equipped with an ultrasonic transmitter and receiver, and can detect the presence or absence of a multi-feed based on the attenuation of the ultrasonic waves.

[0024] The document detection sensor unit 21c is disposed upstream of the roller 159a and downstream of the double feed detection sensor unit 21b, and detects that the leading edge of the document Sh (the downstream edge in the transport direction) has reached the feed roller 151, thereby outputting a predetermined detection signal. The document detection sensor unit 21d is disposed downstream of the roller 159a and upstream of the reading unit 16, and detects that the leading edge of the document Sh has reached the roller 159a and that the trailing edge of the document Sh (the upstream edge in the transport direction) has passed through the roller 159a, thereby outputting a predetermined detection signal. For example, optical sensors are used for the sensor units 21c and 21d, and the presence or absence (arrival and passage) of the document Sh can be detected based on the blocking of light caused by the passage of the document Sh.

[0025] The above-mentioned sensor units 21a to 21d are not limited to those described above, and other known sensors may be used instead.

[0026] The operation input unit 22 is an operation panel that can receive operation input from the user indicating the execution of image reading, and can be installed at any location on the exterior of the housing 10. The operation input unit 22 may also function as a display unit, in which case a touch panel display can typically be used.

[0027] The control unit 23 includes a CPU (Central Processing Unit) 231, a memory 232, and a communication interface 233. The CPU 231 reads a predetermined program and executes image reading while expanding the program on the memory 232. The memory 232 is a concept that encompasses main memory, cache memory, working memory, etc., and is assumed to be a volatile memory such as RAM (Random Access Memory) here, but may also be a concept that further includes non-volatile memory. The CPU 231 also receives input signals from the operation input unit 22, detection signals from the sensor group 21, etc., via the communication interface 233, and can also receive other signals from external devices (not shown).

[0028] With this configuration, the control unit 23 controls the driving of each of the above-mentioned elements based on the input signal from the operation input unit 22, the detection signal from the sensor group 21, etc., so that the series of image reading operations from the intake to the discharge of the original Sh are properly realized. In another embodiment, the control unit 23 may be configured as a semiconductor device such as an ASIC (application specific integrated circuit), i.e., the functions of the control unit 23 may be realized by either hardware or software. Also, the control unit 23 may be provided separately according to its individual functions, such as a drive control unit, an image reading control unit, and a document capture control unit.

[0029] <Internal structure> Fig. 3 is a perspective view showing the internal structure ST14 around the intake port 14. Figs. 4(a) to 4(c) are exploded perspective views of a portion of the internal structure ST14. Details will be described later, but Fig. 4(a) shows the structure of the cam shaft portion 30, Fig. 4(b) shows the structure of the separation unit 152, and Fig. 4(c) shows the structure of the pick arm unit 17. 5 is a schematic side view of the internal structure ST14 in a state (initial state) before the start of fetching of the document stack Sh. FIG. 6 is a schematic side view of the internal structure ST14 in a state after the start of fetching of the last document Sh in the document stack Sh. In FIG. 6, in order to show the state in which the document Sh is in contact with the paper feed roller 151, some elements in the area K are not shown (the same applies to other figures described later).

[0030] -About the document stopper in the upper part of the internal structure As shown in Fig. 4(a), cam shaft 30 is installed in housing 10 so as to be rotatable about shaft A5 as a rotation axis. Cam shaft spring (biasing member) 20e is provided on cam shaft 30 to rotate arm 171, thereby biasing cam shaft 30 in direction D4. Arm support portions 31 that rotate integrally with cam shaft 30 are provided together with abutment portions 312 at both ends of cam shaft 30 in the axial direction (width direction of document Sh).

[0031] 4(b), the separation unit 152 includes a separation roller 153 and a separation holder 154. The separation holder 154 rotatably holds the separation roller 153. The separation unit 152 includes a hole A8 through which the shaft A1 is inserted, and is fixed to the housing 10 so as to be rotatable about the shaft A1 as a rotation axis. The separation unit 152 is pressed toward the paper feed roller 151 by a separation spring (biasing member) 20a, which allows the document Sh to be sandwiched by a nip formed between the paper feed roller 151 and the separation roller 153.

[0032] 4(c), the pick arm unit 17 includes an arm portion 171. The arm portion 171 includes a hole A2 through which the shaft portion A1 is inserted, and the separation unit 152 is rotatable within the housing 10 with the shaft portion A1 as the rotation axis. On the arm unit 171, a plurality of pick rollers 172, which also function as abutment portions that abut against the document Sh, are arranged side by side in the left-right direction (the width direction of the document Sh) and are rotatably supported. In this manner, the document Sh is pressed, and from this perspective, the arm unit 171 and the pick rollers 172 may be referred to as a pressing portion. The plurality of pick rollers 172 are typically arranged symmetrically, and although the number of pick rollers 172 is two in this embodiment, it may also be any even number. Alternatively, the number of pick rollers 172 may also be an odd number so that one of them is located in the center. It should be noted that the pick rollers 172 may be any that are capable of sliding or following the transport of the document Sh. Furthermore, engagement portions 176 including holes A2 are provided at both left and right ends of the arm portion 171. Pick springs (biasing members) 20b are provided at each of the engagement portions 176, and the pick arm unit 17 is biased in direction D6 so that the force with which the pair of left and right pick rollers 172 press against the paper feed roller 151 is equal.

[0033] Here, the arm portion 171 rotates between a standby position P1 (see FIG. 5) and a transport position P2 (see FIG. 6). At the standby position P1, the pick roller 172 retreats to a position where it is separated from the document Sh (document stack Sh) placed on the placement surface f1 (see FIG. 3) and does not abut on the document Sh, and the pick roller 172 does not interfere with or come into contact with the document Sh when the document Sh is placed. On the other hand, at the transport position P2, the pick roller 172 abuts on the document Sh and presses the document Sh against the paper feed roller 151.

[0034] 4(c), a document stopper 173 is supported on the arm 171 so as to be rotatable about a shaft A3 as a rotation axis, and is biased in a direction D3 by a stopper spring (biasing member) 20c. At the standby position P1 (see FIG. 5), the locking portion 1731 is locked to the housing holding portion 174 of the housing 10, and the document stopper 173 is held in an upright position. When the document stopper 173 is in the upright position, the transport path T is at least partially blocked, thereby restricting the intake of the document Sh and arranging the leading edge of the document Sh. On the other hand, at the transport position P2 (see FIG. 6), the locking portion 1731 moves away from the housing holding portion 174, and the document stopper 173 rotates in the direction D3 due to the bias of the stopper spring 20c. As a result, the document stopper 173 changes from the upright position to the tilted position, and the blocked transport path T is opened, allowing the document Sh to be taken in. While the locking portion 1731 and the housing holding portion 174 are separated, the document stopper 173 in the tilted position comes into contact with and is locked by the locking portion 156 of the separation holder 154. With this structure, the document stopper 173 tilts more as the arm portion 171 approaches the transport position P2, and stands more as the arm portion 171 approaches the standby position P1.

[0035] - Upper part of internal structure: Camshaft and arm In the pick arm unit 17, the arm portion 171 is configured to be able to move up and down, as will be described below with reference to FIGS. 4(a) to 4(c).

[0036] The arm support portion 31 extends from the cam shaft portion 30 toward the separation roller 153 (axially inward). When the cam shaft portion 30 rotates in direction D4', the arm support portion 31 engages with the holding portion 175 of the arm portion 171, causing the arm portion 171 to rotate in direction D6' and separate the pick roller 172 from the document Sh. This prevents the document Sh from interfering with the pick roller 172 when it is stacked on the loading tray 13. Furthermore, when the cam shaft portion 30 rotates in direction D4 and comes into contact with an abutment portion (not shown), the arm portion 171 moves away from the arm support portion 31, and the pick roller 172 is pressed in direction D6 by the force of the pick spring 20b so as to come into contact with the document Sh (or the paper feed roller 151).

[0037] With this structure, when the cam shaft portion 30 rotates, the arm portion 171 can rotate between positions P1 and P2 and move up and down. For example, when the number of documents Sh loaded on the loading tray 13 is relatively small, the pick roller 172 rotates to a transport position P2 where it comes into contact with the documents Sh, as shown in FIG. 6. On the other hand, when the number of documents Sh loaded on the loading tray 13 is relatively large, the arm support portion 31 and the holder 175 are separated, and the arm portion 171 is held at the standby position P1. Furthermore, when the number of documents Sh decreases, the arm portion 171 moves to the transport position P2.

[0038] In this embodiment, the cam shaft portion 30 is driven to rotate by the drive source 18b (see FIG. 1), and the drive source 18b rotates forward when the original Sh is transported, and rotates reversely to return to the initial state (see FIG. 5) when the transport of the original Sh is completed.

[0039] A one-way clutch is built into drive transmission unit 19b, which transmits the power of drive source 18b to camshaft unit 30, so that power is transmitted to camshaft unit 30 when drive source 18b rotates in the reverse direction, and the transmission is interrupted when drive source 18b rotates in the forward direction. As a result, when drive source 18b rotates in the reverse direction, camshaft unit 30 rotates in direction D4' based on the power of drive source 18b. By stopping the rotation when camshaft unit 30 reaches a predetermined position, arm unit 171 can be held in standby position P1.

[0040] On the other hand, when the drive source 18b rotates forward at the start of transport of the document Sh, the power to the cam shaft portion 30 is cut off. Therefore, the cam shaft portion 30 rotates in the direction D4 due to the bias of the cam shaft spring 20e until it reaches a transport position where the abutment portion 312 abuts against a rotation stopper (not shown). A stepping motor, which can typically be used for the drive source 18b, allows for highly accurate adjustment of the amount of rotation of the camshaft 30. Therefore, by rotating the drive source 18b in the reverse direction by a specified number of pulses, the camshaft 30 can be moved from the transfer position to a predetermined standby position, and in this case, there is no need to provide a detection sensor that detects that the camshaft 30 has reached the standby position.

[0041] -Lower part of internal structure 3, a feed roller cover 130 is provided on the feed roller 151 on the side of the conveyance path T, and a guide member 131 and a rotating member 32 form conveyance surfaces on the upstream and downstream sides of the feed roller cover 130 on its upper surface. The guide member 131 is supported rotatably around a shaft A4. The rotating member 32 is supported rotatably around a shaft A6.

[0042] The guide member 131 is located upstream of the nip formed between the feed roller 151 and the separation roller 153, and has a placement surface f1 on which the downstream end of the document Sh can be placed before it is taken into the main body of the device 1. Here, on the upper surface of the feed roller cover 130, the rotating member 32 is provided with an extension 321, and the guide member 131 is provided with an abutment portion 1311, which abuts against the extension 321. The guide member 131 is biased by the document table spring (biasing member) 20d in a direction in which the placement surface f1 moves away from the transport path T, and while the guide member 131 and the extension 321 are in contact, the rotating member 32 is biased in direction D7 by the document table spring 20d. In such a guide member 131, for example, in the state shown in Figure 5, the loading surface f1 is located above the upper surface of the paper feed roller 151 (standby position P5), and in the state shown in Figure 6, the loading surface f1 is located below the upper surface of the paper feed roller 151 (conveying position P6).

[0043] A rotating cam 33 is mounted on the housing 10 below the rotating member 32 so as to be rotatable about the shaft A7 as a rotation axis, and is biased in direction D5 by a rotating cam spring (biasing member) 20f. The rotating cam 33 rotates based on power from the drive source 18b via the drive transmission unit 19b. When the rotating cam 33 rotates in direction D5' opposite to direction D5, it abuts against the rotating member 32, thereby pushing it upward. In addition, the extension portion 321 of the rotating member 32 abuts against the abutment portion 1311 of the guide member 131, holding the guide member 131 at the standby position P5.

[0044] Furthermore, when the rotating cam 33 rotates in direction D5, it moves away from the rotating member 32, and the rotating member 32 is held at a position where it abuts against an abutment portion (not shown) due to its own weight. At this time, the abutment portion 1311 of the guide member 131 and the extension portion 321 of the rotating member 32 are released from contact, and the guide member 131 is urged in direction D7 by the platen spring 20d, and is held at transport position P6 where it abuts against an abutment portion (not shown) (see FIG. 6). Note that, although the guide member 131 is urged in direction D7 by the platen spring 20d in this embodiment, the force in direction D7 may be generated by the own weight of the guide member 131 or the own weight of the document Sh.

[0045] A one-way clutch is built into drive transmission unit 19b, which transmits the power of drive source 18b to rotating cam 33, so that the power is transmitted to rotating cam 33 when drive source 18b rotates in the reverse direction, and the transmission is interrupted when drive source 18b rotates in the forward direction. As a result, when drive source 18b rotates in the reverse direction, rotating cam 33 rotates in direction D5' based on the power of drive source 18b. By stopping the rotation of rotating cam 33 when it reaches a predetermined position, guide member 131 can be held at standby position P5.

[0046] On the other hand, when the drive source 18b rotates forward to start transporting the document Sh, the power to the rotating cam 33 is cut off. Therefore, the rotating cam 33 rotates in direction D5 due to the bias of the rotating cam spring 20f until the abutment portion (not shown) abuts against the rotation stopper. Both the abutment between the rotating cam 33 and the rotating member 32 and the abutment between the rotating member 32 and the guide member 131 are released, and the guide member 131 rotates to the transport position P6 due to the document table spring 20d.

[0047] <About paper feeding> In this embodiment, the position of the arm portion 171 varies based on whether the weight of the document S on the loading tray 13 meets a standard. For example, if the document S is relatively light, the arm portion 171 moves from the standby position P1 to the transport position P2.

[0048] -Feeding operation when the weight of the document stack is relatively small 7A to 7C are schematic side views of the internal structure ST14 when a small number of documents Sh are loaded on the loading tray 13 and their weight is relatively light. Fig. 7A shows the state (initial state) before the start of fetching the document stack Sh, Fig. 7C shows the state after the start of fetching the last document Sh in the document stack Sh, and Fig. 7B shows the state between them.

[0049] In the state shown in FIG. 7A, the arm portion 171 is held at the standby position P1. When the paper feed operation starts, a force is applied to the arm portion 171 by the pick spring 20b to rotate it in the direction D6. At this time, the document stopper 173 is pressed in the direction D3 by the biasing force of the stopper spring 20c as well as the weight of the document stack Sh, and friction occurs between the locking portion 1731 of the document stopper 173 and the housing holding portion 174. In the example shown in FIG. 7A, the document stack Sh is relatively small, and its weight is relatively light. Therefore, the force pressing the document stopper 173 in the direction D3 is small, and the frictional force between the locking portion 1731 of the document stopper 173 and the housing holding portion 174 is smaller than the force rotating the arm portion 171 in the direction D6.

[0050] Therefore, when the paper feeding operation starts, the arm portion 171 descends onto the document stack Sh (see FIGS. 7B and 7C). At the same time, the document stopper 173 assumes a tilted position, and the transport of the document Sh is not obstructed by the document stopper 173. Furthermore, in addition to the guide member 131 retreating to the transport position P6, the pick roller 172 of the arm portion 171 is pressed against the document stack Sh, and the single document Sh located at the bottom of the document stack Sh is pressed against the paper feed roller 151. Therefore, the single document Sh is properly transported in the transport direction D0 by the paper feed roller 151, which means that non-feeding of the document Sh can be prevented.

[0051] Furthermore, in the case of a plastic card, a booklet (e.g., a passport), a paper material with a thick tip due to curling, etc., even if the weight of the document is relatively small, the document stopper 173 quickly assumes a tilted position when the paper feed operation starts, as described above. Therefore, the document stopper 173 does not interfere with the transport of the document Sh.

[0052] -Feeding operation when the weight of the document stack is relatively large 8A to 8D are schematic side views of the internal structure ST14 when a large number of documents Sh are loaded on the loading tray 13 and the documents / these documents are relatively heavy in weight. Fig. 8A shows the state before the start of fetching the document stack Sh (initial state), Fig. 8D shows the state after the start of fetching the last document Sh in the document stack Sh, and Figs. 8B and 8C show the states between them in chronological order.

[0053] In the state shown in FIG. 8A, the arm portion 171 is held at the standby position P1. When the paper feed operation starts, a force is applied to the arm portion 171 by the pick spring 20b to rotate it in the direction D6. At this time, the document stopper 173 is pressed in the direction D3 by the biasing force of the stopper spring 20c as well as the weight of the document stack Sh, and friction occurs between the locking portion 1731 of the document stopper 173 and the housing holding portion 174. In the example shown in FIG. 8A, the document stack Sh is relatively large and its weight is relatively heavy. Therefore, the force pressing the document stopper 173 in the direction D3 is large, and the frictional force between the locking portion 1731 of the document stopper 173 and the housing holding portion 174 is greater than the force rotating the arm portion 171 in the direction D6.

[0054] 7A and 8A, the frictional force between the locking portion 1731 of the document stopper 173 and the housing holding portion 174 varies depending on the weight of the document stack Sh. When the weight of the document stack Sh is relatively large (see FIG. 8A), even when the feeding operation is started, the arm portion 171 does not descend onto the document stack Sh, and the document stopper 173 is maintained in an upright position (see FIG. 8B). Therefore, the upper document Sh in the document stack Sh abuts against the document stopper 173. Meanwhile, the guide member 131 retreats to the transport position P6, and a gap is formed between the upright document stopper 173 and the feed roller 151, allowing the passage of the lowest document Sh. Therefore, the transport of the document Sh is not impeded by the document stopper 173. Note that in this embodiment, since double feeding can be appropriately prevented, the gap only needs to be large enough to allow the passage of at least one document Sh.

[0055] With this configuration, when the weight of the document stack Sh is relatively large, the document stopper 173 limits the document stack Sh that is transported to the nip portion between the feed roller 151 and the separation roller 153. This makes it possible to prevent a situation in which the document stack Sh is transported to the nip portion all at once, causing unexpected double feeding.

[0056] Furthermore, the single document Sh located at the bottom is pressed against the paper feed roller 151 by the weight of the entire document stack Sh, so that the single document Sh and the paper feed roller 151 are unlikely to slip against each other, making it possible to prevent non-feeding of the document Sh.

[0057] As the transport continues and the amount of document stack Sh on the loading tray 13 decreases, the force of the document stack Sh pressing the document stopper 173 in direction D3 due to its own weight decreases. When the frictional force between the locking portion 1731 of the document stopper 173 and the housing holding portion 174 becomes smaller than the force rotating the arm portion 171 in direction D6, the arm portion 171 descends onto the document stack Sh (see FIGS. 8C and 8D). Accordingly, the document stopper 173 assumes a tilted position, so that the transport of the documents Sh is not impeded by the document stopper 173. Furthermore, the pick roller 172 of the arm portion 171 presses against the document stack Sh, and the lowest document Sh in the document stack Sh is pressed against the paper feed roller 151. Therefore, the document stack Sh is properly transported in the transport direction D0 by the paper feed roller 151, which prevents the document Sh from being misfed.

[0058] <Modification> The contents of the above embodiment can be modified without departing from the spirit of the invention. For example, in the embodiment, an example has been given in which the behavior of the document stopper 173 is controlled in accordance with the weight of the document stack Sh. However, this behavior is not limited to this example, and it may be controlled in accordance with the thickness of the document stack Sh instead of the weight of the document stack Sh. Also, a detection sensor that detects the weight and / or thickness may be provided on the loading tray 13, and the behavior of the document stopper 173 may be controlled based on the detection results. Furthermore, the behavior of the document stopper 173 may be controlled by providing a separate drive source rather than by frictional force.

[0059] Furthermore, in the embodiment, when the weight of the document stack Sh is relatively large, the guide member 131 moves to the transport position P6 upon start of the document feeding operation, the document stopper 173 maintains an upright position, and a gap through which the documents Sh can pass is formed between the document stopper 173 and the document feed roller 151. However, this gap is not limited to this example, and may be formed by moving the document stopper 173. In that case, the relative position of the guide member 131 with respect to the housing 10 may be fixed, or the document feed roller 151 may always be positioned above the upper surface of the guide member 131 (the placement surface f1 may always be positioned below the upper surface of the document feed roller 151).

[0060] 1 are provided independently of each other, they may be provided as a common drive source. In this case, a clutch for switching between transmitting and blocking the power, a delay mechanism for delaying the power transmission, or the like may be provided in the power transmission path from the common drive source to each roller.

[0061] In addition, in the embodiment, the drive source 18b is configured to rotate the guide member 131 under the control of the control unit 23, but the guide member 131 may be configured to be mechanically linked to the rotation of the arm unit 171. Furthermore, the guide member 131 may be linked to the arm unit 171 by a link mechanism, and may rotate as the arm unit 171 rotates from the standby position P1 to the transport position P2. A drive source may be provided separately for each of the rotating elements.

[0062] In addition, in the embodiment, the guide member 131 is configured to be moved toward the transport path T by the cam member and to be retracted from the transport path T by the document table spring 20d, but these actions may be reversed. That is, the guide member 131 may be moved toward the transport path T by the document table spring 20d and retracted from the transport path T by the cam member.

[0063] <Other> The originals Sh may be fed into the device body as described with reference to the original feeding device 1, but may also be fed to another device outside the device. In other words, feeding may be broadly interpreted as conveying, and the original feeding device 1 can be said to be one aspect of an original conveying device.

[0064] In the embodiments, individual elements are named based on their main functions, but the functions described in the embodiments may be sub-functions and are not strictly limited to these names. Furthermore, these names can be replaced with similar names. For the same purpose, the term "unit" can be replaced with "tool," "component," "member," "structure," "assembly," etc. Alternatively, these terms may be omitted or added. Furthermore, terms such as "first" and "second" used to distinguish between elements do not indicate priority or importance.

[0065] Two or more elements illustrated as selectable in the embodiments are not strictly limited to the examples and may be arbitrarily combined, for example, each of the two or more illustrated elements may be additionally or alternatively selected. For example, when two elements A and B are arbitrarily combined, they may be expressed as "A and / or B" or "at least one of A and B" to indicate either A only, B only, or both A and B.

[0066] <Summary> Some features exemplified in the embodiments are as follows: [1] a conveying means for conveying documents one by one from a document stack that is a bundle of a plurality of documents; a document stopper for arranging the leading edge of the document stack; The document stopper is a first position that blocks at least a portion of the document transport path; a second position in which the conveying path is at least partially opened; and when the weight of the document stack does not satisfy a standard, the document stack is moved from the first position to the second position. A document transport device characterized by: [2] The document stopper is a locking portion that locks with a part of the housing so as to maintain the first attitude; The friction force between the locking portion and a part of the housing is configured to vary based on the weight of the document stack. The document transport device according to [1], [3] the document stopper is attached to a pressing portion that presses the document, the pressing section is configured to be movable between a conveying position where it presses the document so that the document can be conveyed and a standby position where it is spaced apart from the document, The document stopper moves between the first position and the second position in conjunction with the movement of the pressing portion. The document transport device according to [1] or [2], [4] The transport means includes a paper feed roller for taking the document from outside the housing into the housing. The document transport device according to any one of [1] to [3], characterized in that: [5] When the document stopper is in the first position, a gap is formed between the document stopper and the paper feed roller that allows at least one document to pass through. The document transport device according to [4], [6] The document reader further includes a guide member for guiding the document; The guide member is Before the document is conveyed, the sheet feed roller is positioned above the upper surface of the sheet feed roller, During the transport of the document, a sheet is positioned below the upper surface of the paper feed roller. The document transport device according to [4] or [5],

[0067] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention. [Explanation of symbols]

[0068] Sh: original, 1: original feeding device (original transport device), 10: housing, 11: discharge port, 12: discharge tray, 13: Loading tray, 130: Paper feed roller cover, 131: Guide member, 1311: contact portion, 14: intake port, 15: conveying mechanism, 151: paper feed roller, 152: separation unit, 153: separation roller, 154: Separation holder, 156: Locking portion, 16: Reading unit, 17: Pick arm unit, 171: Arm unit, 172: Pick roller, 173: Document stopper, 1731: Locking portion, 174: Housing holding portion, 175: Holding portion, 176: Engagement portion, 20a: Separation spring, 20b: Pick spring, 20c: Stopper spring, 20d: document table spring, 20e: cam shaft spring, 20f: rotary cam spring, 30: Camshaft portion, 31: Arm support portion, 312: Abutment portion, 32: Rotating member, 321: extension, 33: rotating cam.

Claims

1. a conveying means for conveying documents one by one from a document stack that is a bundle of a plurality of documents; a document stopper for arranging the leading edge of the document stack; The document stopper is a first position that blocks at least a portion of the document transport path; a second position in which the conveying path is at least partially opened; and when the weight of the document stack does not satisfy a standard, the document stack is moved from the first position to the second position. A document transport device characterized by:

2. The document stopper is a locking portion that locks with a part of a housing so as to maintain the first attitude; The friction force between the locking portion and a part of the housing is configured to vary based on the weight of the document stack.

2. The document transport device according to claim 1.

3. the document stopper is attached to a pressing portion that presses the document, the pressing section is configured to be movable between a conveying position where it presses the document so that the document can be conveyed and a standby position where it is spaced apart from the document, The document stopper moves between the first position and the second position in conjunction with the movement of the pressing portion.

2. The document transport device according to claim 1.

4. The transport means includes a paper feed roller for taking the document from outside the housing into the housing.

2. The document transport device according to claim 1.

5. When the document stopper is in the first position, a gap is formed between the document stopper and the paper feed roller that allows at least one document to pass through.

5. The document transport device according to claim 4.

6. The document reader further includes a guide member for guiding the document; The guide member is Before the document is conveyed, the sheet feed roller is positioned above the upper surface of the sheet feed roller, During the transport of the document, a sheet is positioned below the upper surface of the paper feed roller.

5. The document transport device according to claim 4.

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