Image reading device

Abstract

To provide a medium feeding device that can be stably installed or can stably feed a medium, and an image reading device including the same.SOLUTION: An image reading device comprises: a feeding roller 13 that feeds a medium placed on a medium placement part 11; a conveying roller 20 that is provided on the downstream side of the feeding roller 13; a first driving source that drives at least the feeding roller 13; a second driving source 32 that drives at least the conveying roller 20; and a housing 7 that includes therein the feeding roller 13, conveying roller 20, first driving source, and second driving source 32. The housing 7 includes a lower unit that constitutes a lower portion of the housing 7, and an upper unit 3 that opens and closes with respect to the lower unit. The first driving source and the second driving source 32 are provided on both sides with respect to a center part of the lower unit in a width direction intersecting with a medium conveyance direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a medium feeding device that feeds a medium, and an image reading device that includes the medium feeding device. [Background technology]

[0002] 2. Description of the Related Art In a scanner, which is an example of an image reading device, drive sources for various drive systems are provided inside the device body. For example, in Patent Document 1, a stepping motor is used as a drive source for moving the optical system of a copying machine.

[0003] Incidentally, scanners are sometimes provided with a medium feeding device (also called an ADF (Auto Document Feeder)) that automatically feeds documents as media, and are configured to automatically feed and read multiple documents to an image reading unit fixed within the device (for example, Patent Document 2). The media feeding device installed in such a scanner includes a feed roller that feeds the document placed on the document tray, a transport roller that sends the document fed by the feed roller to the image reading unit, and the like, and these are driven by a drive source such as a motor.

[0004] Here, if a stepping motor such as that disclosed in Patent Document 1 is used as the drive source of a medium feeding device that feeds documents to the image reading unit fixed inside the device, there is a risk that the transport of the documents will be disturbed if a load fluctuation occurs in the drive source during scanning in the image reading unit, which may result in a disturbance in the read image. For this reason, some medium feeding devices use a DC motor as the drive source (for example, Patent Document 3 and Patent Document 4). By providing an encoder to the DC motor, feedback control can be performed in response to fluctuations in the load on the motor, and distortion of the read image due to fluctuations in the load on the motor can be easily suppressed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 4-242234 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-60494 [Patent Document 3] Japanese Patent Application Publication No. 6-54132 [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-10855 Summary of the Invention [Problem to be solved by the invention]

[0006] In scanners equipped with such media feeding devices, users need to make the device even smaller, but there is a limit to the space available for placing a drive source such as a motor, which is relatively heavy and large, and there are also restrictions on the layout of the components. In particular, in small scanners, such as the scanner described in Patent Document 2, where the housing that makes up the scanner is divided into an upper unit (cover portion 11b) and a lower unit (main body portion 11a), and the upper unit is configured to be openable and closable relative to the lower unit for maintenance of the media feeding device, etc., the weight balance when the upper unit is open is also important.

[0007] In view of the above problems, an object of the present invention is to provide a medium feeding device that can be stably installed and an image reading device equipped with the same, and also to provide a medium feeding device or an image reading device that can stably feed media. [Means for solving the problem]

[0008] In order to solve the above problem, the medium feeding device of the first aspect of the present invention comprises a feed roller that feeds a medium placed on a medium loading section, a transport roller that is arranged downstream of the feed roller, a first drive source that drives at least the feed roller, a second drive source that drives at least the transport roller, and a housing that houses the feed roller, the transport roller, the first drive source, and the second drive source, wherein the housing comprises a lower unit that forms the lower part of the housing, and an upper unit that opens and closes relative to the lower unit, and the first drive source and the second drive source are arranged on both sides of the center of the lower unit in a width direction that intersects with the medium transport direction.

[0009] According to this aspect, the medium feeding device uses two drive sources, the first drive source and the second drive source, and the first drive source and the second drive source are respectively provided on both sides of the center of the lower unit in a direction intersecting the medium transport direction, thereby improving the weight balance of the medium feeding device. Furthermore, since both the first drive source and the second drive source are provided in the lower unit, the stability of the housing can be maintained even when the upper unit is opened relative to the lower unit. As a result, the medium feeding device can be installed stably.

[0010] A medium feeding device according to a second aspect of the present invention is characterized in that, in the first aspect, it comprises a separation roller that nips the medium between itself and the feed roller to separate it, a downstream conveying roller arranged downstream of the conveying roller, a pressing unit that is arranged to be able to move forward and backward relative to the feed roller and that advances toward the feed roller to press the medium placed on the medium loading section toward the feed roller, and a regulating unit that is switchable between a restricting state that restricts the advancement of the pressing unit toward the feed roller and an allowing state that allows the advancement of the pressing unit toward the feed roller, and the separation roller, the downstream conveying roller, and the regulating unit are driven by the second driving source.

[0011] According to this aspect, the separation roller, the downstream transport roller, and the regulating portion can be driven by a drive source (second drive source) common to the transport roller.

[0012] A medium feeding device according to a third aspect of the present invention is characterized in that, in the first or second aspect, the first drive source and the second drive source are DC motors, and the medium feeding device is equipped with a first encoder that detects the amount of rotation of a scale that rotates in response to driving of the first drive source, a second encoder that detects the amount of rotation of the scale that rotates in response to driving of the second drive source, and a control unit that controls the driving of the corresponding drive source based on information detected by the first encoder or the second encoder.

[0013] According to this aspect, the control unit controls the driving of the corresponding driving source based on the information detected by the first encoder or the second encoder, thereby driving the feed roller or the transport roller in accordance with the rotational status of the driven object. Therefore, it is possible to suppress disturbances in transport when the medium is fed by the first drive source or the second drive source.

[0014] A medium feeding device according to a fourth aspect of the present invention is characterized in that, in the third aspect, the first driving source is arranged such that the direction along the width direction is the axial direction of the motor output shaft of the first driving source, a first transmission mechanism part that is connected to the motor output shaft extending from the motor main body of the first driving source and transmits the power of the motor is attached so as to be positioned outside the motor main body in the width direction, and the first encoder is arranged inside the motor main body of the first driving source in the width direction.

[0015] According to this aspect, the first driving source is disposed with the axial direction of the motor output shaft aligned along the width direction, a first transmission mechanism that is connected to the motor output shaft extending from the motor body and transmits the motor's power is attached so as to be positioned outside the motor body in the width direction, and the first encoder is provided inside the motor body of the first driving source in the width direction, so that the first encoder can be disposed in a space-saving manner in the width direction, thereby making it possible to make the device compact in size in the width direction.

[0016] A medium feeding device according to a fifth aspect of the present invention is characterized in that, in the third or fourth aspect, the second drive source is arranged such that the direction along the width direction is the axial direction of the motor output shaft of the second drive source, a second transmission mechanism unit that is connected to the motor output shaft of the second drive source extending from the motor main body of the second drive source and transmits the power of the motor is attached so as to be positioned outside the motor main body of the second drive source in the width direction, a rotating shaft having the conveying roller, and a one-side holder that is attached to one side end of the rotating shaft in the axial direction on the side where the second drive source is arranged and has a drive gear that receives power from the second drive source via the second transmission mechanism unit and rotates the rotating shaft, a D-cut portion having a cross section shaped like a cut part of a circle is formed at the one-side end of the rotating shaft, a D-cut hole that is shaped corresponding to the D-cut portion and into which the D-cut portion is press-fitted is formed in the one-side holder and is configured to rotate integrally with the rotating shaft.

[0017] In order to achieve highly accurate transport by the transport roller, it is desirable that the scale of the second encoder be provided so as to rotate integrally with the rotation shaft. On the other hand, if the engagement between the rotating shaft and the one-side holder that includes a drive gear that rotates the rotating shaft is achieved by press-fitting the one-side end, which has a D-cut shape with a cross section of a circle with a portion cut out, into a D-cut hole in the one-side holder, there is a risk that the drive gear of the one-side holder will become eccentric due to the press-fitting. Therefore, if the scale of the second encoder is provided in the one-side holder, the scale will also become eccentric along with the drive gear, and there is a risk that the rotation of the rotating shaft cannot be detected accurately.

[0018] According to this aspect, the scale of the second encoder is provided outside the one-side holder and is configured to rotate integrally with the rotating shaft, so that the rotation of the rotating shaft can be detected with reduced influence of the eccentricity, enabling highly accurate control of the conveying roller.

[0019] A medium feeding device according to a sixth aspect of the present invention is characterized in that, in the fifth aspect, the scale of the second encoder is attached to a round press-fit holder into which the rotating shaft is pressed and attached integrally to the rotating shaft.

[0020] According to this aspect, the scale of the second encoder is attached to a round press-fit holder in which the rotating shaft is pressed into a circular hole and attached integrally to the rotating shaft. This reduces the effect of eccentricity in the one-side holder in which the rotating shaft is pressed into a D-cut hole, and allows the scale of the second encoder to be attached so as to rotate integrally with the rotating shaft.

[0021] A medium feeding device according to a seventh aspect of the present invention is characterized in that, in the sixth aspect, the round press-fit holder is provided on the other side of the axial direction of the rotating shaft relative to the one side end of the rotating shaft.

[0022] According to this aspect, the round press-fit holder to which the scale of the second encoder is attached is provided on the other side of the axial direction of the rotating shaft relative to the one side end of the rotating shaft, i.e., the one side holder and the round press-fit holder are provided on both sides of the rotating shaft, so the width dimension of the device can be reduced compared to a configuration in which both the one side holder and the round press-fit holder are provided on the same side of the rotating shaft.

[0023] The medium feeding device according to the eighth aspect of the present invention is characterized in that, in any of the first to seventh aspects, a timing belt is used in the first transmission mechanism unit or the second transmission mechanism unit.

[0024] According to this aspect, it is possible to transmit power from each of the first and second drive sources while reducing the influence of vibrations of the first and second drive sources.

[0025] An image reading device according to a ninth aspect of the present invention is characterized in that it comprises a reading unit that reads a medium, and a medium feeding device according to any one of the first to eighth aspects that feeds the medium toward the reading unit.

[0026] According to this aspect, in an image reading device equipped with a reading unit that reads a medium and a medium feeding device that feeds the medium toward the reading unit, the same effects as any of the first to eighth aspects can be obtained. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a perspective view showing a scanner according to the present invention; [Figure 2] FIG. 2 is a perspective view showing a feeding state in the scanner according to the present invention. [Figure 3] FIG. 3 is a rear perspective view of the scanner shown in FIG. 2. [Figure 4] FIG. 2 is a side cross-sectional view showing a feeding path in the scanner according to the present invention. [Figure 5] FIG. 2 is a rear view of the main body of the scanner according to the present invention. [Figure 6]FIG. 2 is a rear perspective view of the device main body on the side where a second driving source is arranged. [Figure 7] FIG. 2 is a rear perspective view of the device main body on the side where a first driving source is arranged. [Figure 8] FIG. [Figure 9] FIG. 3 is a perspective view showing drive system components in the device main body. [Figure 10] FIG. 4 is a perspective view showing a drive mechanism of a feed roller. [Figure 11] FIG. 4 is a perspective view showing a drive mechanism for a separation roller. [Figure 12] FIG. 10 is a perspective view of the upper unit in an open state relative to the lower unit. [Figure 13] FIG. 13 is a perspective view showing part B in FIG. 12 from a different angle. [Figure 14] 5A and 5B are diagrams illustrating the operation of a restricting portion. [Figure 15] FIG. [Figure 16] FIG. [Figure 17] FIG. 1 is a block diagram of a scanner according to the present invention. [Figure 18] FIG. 10 is a perspective view showing a state in which the seventeenth transmission gear is removed from the side of the apparatus body where the second drive source is arranged. DETAILED DESCRIPTION OF THE INVENTION

[0028] [Example 1] First, an overview of an image reading device according to an embodiment of the present invention will be described. As an example of the image reading device in this embodiment, a document scanner (hereinafter simply referred to as scanner 1) capable of reading at least one of the front and back sides of a document as an example of a medium will be taken as an example. FIG. 1 is a perspective view showing a scanner according to the present invention. FIG. 2 is a perspective view showing a feeding state in the scanner according to the present invention. FIG. 3 is a rear perspective view of the scanner shown in FIG. 2. FIG. 4 is a side cross-sectional view showing a feeding path in the scanner according to the present invention. FIG. 5 is a rear view of the device body of the scanner according to the present invention. FIG. 6 is a rear perspective view of the device body on the side where a second drive source is arranged. FIG. 7 is a rear perspective view of the device body on the side where a first drive source is arranged. FIG. 8 is a side view of the device body.

[0029] Fig. 9 is a perspective view showing drive system components in the device main body. Fig. 10 is a perspective view showing a drive mechanism for a feed roller. Fig. 11 is a perspective view showing a drive mechanism for a separation roller. Fig. 12 is a perspective view when the upper unit is in an open state relative to the lower unit. Fig. 13 is a perspective view showing part B in Fig. 12 from a different angle. Fig. 14 is a diagram explaining the operation of the regulating unit. Fig. 15 is a perspective view of an eighth transmission gear. Fig. 16 is a plan view of the eighth transmission gear. Fig. 17 is a block diagram of a scanner according to the present invention.

[0030] <Scanner Overview> Scanner 1 (FIG. 1) as an image reading device according to the present invention comprises a housing 7 that forms part of the exterior of the device, and a device main body 9 provided within housing 7. Device main body 9 comprises medium feeding device 10, which is one embodiment of the "medium feeding device" according to the present invention, and image reading unit 21 (FIG. 4) that reads an image of a document fed by medium feeding device 10. The housing 7 is made up of a lower unit 2 that forms the lower part of the housing 7, and an upper unit 3 that opens and closes relative to the lower unit 2.

[0031] In the XYZ coordinate system shown in each figure, the X direction is the device width direction and paper width direction, and the Y direction is the paper transport direction. The Z direction is the direction that intersects with the Y direction and is generally perpendicular to the surface of the transported paper. The +Y direction side is the front side of the device, and the -Y direction side is the rear side of the device. When viewed from the front side of the device, the right side is the +X direction and the left side is the -X direction. The +Z direction is the top of the device (including the upper part, top surface, etc.) and the -Z direction side is the bottom of the device (including the bottom, bottom surface, etc.). In addition, the scanner 1 is configured so that paper P as a medium is transported in the +Y direction in each drawing. Hereinafter, the direction in which paper P is transported (+Y direction side) will be referred to as "downstream," and the opposite direction (-Y direction side) will be referred to as "upstream."

[0032] The upper unit 3 is attached to the lower unit 2 so as to be rotatable around the downstream side (+Y side) in the paper transport direction relative to the lower unit 2. The upper unit 3 can be in a closed state (see FIG. 2) in which it is closed relative to the lower unit 2 to form a paper transport path for paper P together with the lower unit 2, or in an open state (see FIG. 12) in which it is rotated toward the front of the device relative to the lower unit 2 to expose the paper transport path for paper P and facilitate maintenance such as clearing jams of paper P.

[0033] A paper support 4 that opens and closes relative to the upper unit 3 is provided above the upper unit 3. The paper support 4 is a "medium support" that supports a document (hereinafter sometimes referred to as "paper P") as an example of a medium when in the open state (see FIG. 2).

[0034] The paper support 4 can be in a non-feeding state in which it covers the top of the upper unit 3 and the feed opening 6 (Figure 2) as shown in Figure 1, or in a feeding state in which it rotates from the non-feeding state in Figure 1 to the rear side of the device as shown in Figure 2, opening the feed opening 6 and allowing paper P to be set on the back side of the paper support 4 (media loading section 11 for paper P).

[0035] Additionally, an auxiliary paper support 15 (Figs. 2 and 3) is provided upstream of the paper support 4. The auxiliary paper support 15 is configured to be retractable and retractable into the hollow paper support 4. By pulling out the auxiliary paper support 15, it is possible to stably support paper P even if the side along the conveyance direction is long.

[0036] The lower unit 2 has an outlet 8 on the front side of the device through which paper P is discharged. The lower unit 2 also has a paper output tray 5 that can be pulled out from the outlet 8 toward the front side of the device. The paper output tray 5 can be stored in the bottom of the lower unit 2 (see FIG. 1) or pulled out toward the front side of the device (see FIG. 2). In this embodiment, the paper output tray 5 is made up of multiple connected tray members, and the length that it is pulled out from the outlet 8 can be adjusted depending on the length of the paper P to be discharged.

[0037] <About the feeding path in the scanner> Next, the paper transport path in the scanner 1 will be described with reference to FIG. The paper P to be set in the feed opening 6 is placed on the medium placement section 11. A plurality of sheets of paper P can be set in the feed opening 6. 4, reference numeral 12 denotes a pair of edge guides (see also FIG. 2) that guide both side edges in the width direction (X-axis direction) of the paper P. The edge guides 12 are provided so as to be slidable in the X-axis direction according to the size of the paper P.

[0038] The paper P set in the feed port 6 is fed by the medium feed device 10 and sent toward the image reading unit 21, which will be described later. The medium feed device 10 includes a feed roller 13 that feeds the paper P placed on the medium loading unit 11, and a transport roller 20 that is provided downstream of the feed roller 13. The drive mechanism of the medium feed device 10 will be described in detail later. A separation roller 14 is provided at a position opposite the feed roller 13 to nip and separate the paper P between the feed roller 13 and the separation roller 14 . The outer circumferential surfaces of the feeding roller 13 and the separation roller 14 are made of a high-friction material (for example, an elastomer such as rubber).

[0039] The paper P is picked up by a feed roller 13 rotatably provided relative to the lower unit 2 and fed downstream (+Y direction). Specifically, the feed roller 13 rotates while contacting the surface of the paper P that faces the loading surface of the medium loading section 11, thereby feeding the paper P downstream. Therefore, when multiple sheets of paper P are set in the feed port 6 of the scanner 1, the paper is fed downstream in order starting from the bottom.

[0040] In Fig. 4, the symbol G indicates a stack of sheets placed on the medium placement section 11. Before feeding begins, the leading edge of the stack of sheets G is held in a feeding standby position (the position in Fig. 4) by a flap 38, and the stack of sheets G is prevented from entering between the feeding roller 13 and the separation roller 14. The flap 38 is provided in a pressing unit 39 (Fig. 8). The pressing unit 39 advances to press the paper P placed on the medium placement section 11 toward the feed roller 13 side.

[0041] A restricting portion 40 is provided around the feed roller 13. The restricting portion 40 is configured to be switchable between a restricting state in which the pressing unit 39 is restricted from advancing toward the feed roller 13 and an allowing state in which the pressing unit 39 is allowed to advance toward the feed roller 13. Before feeding begins, the document stack G is supported from below by the regulating portion 40, which is in a regulated state, and is pushed up and separated from the feed roller 13. In other words, contact with the feed roller 13 is prevented. The drive mechanism of the regulating portion 40 will be described in detail later.

[0042] When document feeding begins, the restricting portion 40 retreats downward, the bottom document in the document stack G comes into contact with the feed roller 13, and the flap 38 enters a swingable state (a state in which its position can be switched). Therefore, the bottom document is sent downstream by the rotation of the feed roller 13. The flap 38 swings downstream due to the document sent downstream, and assumes a position that opens the medium feeding path.

[0043] A transport roller 20 is provided downstream of the feed roller 13. The transport roller 20 is configured to include a transport drive roller 23 provided in the lower unit 2 and a transport driven roller 24 provided in the upper unit 3 that rotates in response to the transport drive roller 23.

[0044] The paper P fed by the feed roller 13 is transported along a transport path 30 formed by mutually opposing guide surfaces. Of the mutually opposing guide surfaces, the surface that supports the paper P from below is referred to as a lower guide surface 29a, and the surface opposite the lower guide surface 29a is referred to as an upper guide surface 29b. The feed roller 13 and the transport drive roller 23 are arranged so that a part of them protrudes from the lower guide surface 29a.

[0045] An image reading unit 21 is provided downstream of the transport rollers 20 as a “reading unit” that reads an image, and the paper P is transported to the image reading unit 21 by the transport rollers 20. The image reading unit 21 includes an upper image reading sensor 25 provided on the upper unit 3 side and a lower image reading sensor 26 provided on the lower unit 2 side. In this embodiment, the upper image reading sensor 25 and the lower image reading sensor 26 are configured as contact image sensor modules (CISMs), for example.

[0046] After the image on at least one of the front and back sides of the paper P is read in the image reading unit 21, the paper P is sent by discharge rollers 22 located downstream of the image reading unit 21 and discharged from a discharge opening 8 provided on the front side of the lower unit 2. The discharge rollers 22 are composed of a discharge drive roller 27 provided in the lower unit 2 and a discharge driven roller 28 provided in the upper unit 3 that rotates in response to the discharge drive roller 27. When the paper discharge tray 5 is pulled out, the paper P discharged from the discharge port 8 is stacked on the paper discharge tray 5.

[0047] <About the media feeding device> Next, the above-mentioned medium feeding device 10 will be described in more detail. First, the medium feeding device 10 (FIGS. 5 and 6) has two driving sources: a first motor 31 serving as a "first driving source" that drives the feed roller 13, and a second motor 32 serving as a "second driving source" that drives the transport roller 20. The first motor 31 and the second motor 32 are provided in the same housing 7 as the feed roller 13 and the transport roller 20.

[0048] As shown in Figure 5, the first motor 31 and the second motor 32 are arranged so as to be located on both sides of the center A of the lower unit 2 in the width direction (X-axis direction) that intersects with the medium transport direction (Y-axis direction). In this way, by arranging the two drive sources (first motor 31 and second motor 32) on either side of the center of the lower unit in the width direction of the device, the weight balance of the scanner 1 equipped with the medium feeding device 10 can be improved. Furthermore, since both the first motor 31 and the second motor 32 are provided in the lower unit 2, the stability of the housing 7 can be maintained even when the upper unit 3 is opened relative to the lower unit 2. As a result, the scanner 1 can be installed stably.

[0049] Next, the drive mechanism of the medium feeding device 10 will be described. First, the drive mechanism of the feed roller 13 driven by the first motor 31 will be described. In this embodiment, the first motor 31 is a DC motor, and is configured to include a motor main body 31a and a motor output shaft 31b extending from the motor main body 31a, as shown in Fig. 10. The first motor 31 is disposed such that the axial direction of the motor output shaft 31b of the first motor 31 is the device width direction (X-axis direction). The first motor 31 has a motor body 31a fixed to a right side frame 33 (FIG. 7) provided on the right side (+X side) when viewed from the front of the device. A left side frame 34 (FIG. 6) is provided on the left side (-X side) when viewed from the front of the device.

[0050] A first transmission gear 41 serving as a "first transmission mechanism" for transmitting the power of the motor to the feed roller 13 is connected to the motor output shaft 31b of the first motor 31, and the first transmission gear 41 is attached so as to be located on the outer side (+X side) of the motor body 31a in the device width direction. In this embodiment, the first transmission gear 41 is located on the outer side of the right side frame 33 (see FIGS. 7 and 10).

[0051] 7, the power of the first motor 31 is transmitted from the first transmission gear 41 to the second transmission gear 42 via a timing belt 49. The second transmission gear 42 is engaged with the third transmission gear 43, and the third transmission gear 43 is engaged with the fourth transmission gear 44. A rotation shaft 47 of the fourth transmission gear 44 extends inside the right side frame 33 (between the right side frame 33 and the left side frame 34), and a fifth transmission gear 45 is provided at the -X side end located inside the right side frame 33 (FIG. 10).

[0052] The fifth transmission gear 45 shown in Figure 10 is engaged with a sixth transmission gear 46 provided at the +X side end of the rotation shaft 48 of the feed roller 13, and the power of the first motor 31 is transmitted to the feed roller 13 by these gear trains. In this embodiment, when power is transmitted from the first transmission gear 41 provided on the motor output shaft 31b of the first motor 31 to the second transmission gear 42, the power can be transmitted via a timing belt 49, reducing the influence of vibrations of the first motor 31.

[0053] The first motor 31 is also provided with a first scale 36 that rotates in response to the drive of the first motor 31, and a first encoder 37 that detects the amount of rotation of the first scale 36. The scanner 1 is also provided with a control unit 35 (FIG. 17), which is configured to control the drive of the first motor 31 based on information detected by the first encoder 37. By controlling the drive of the first motor 31 based on the information detected by the first encoder 37, the feed roller 13 can be driven in accordance with the rotational state of the object to be driven, and transport disturbances when feeding paper can be suppressed.

[0054] Here, the first encoder 37 is provided on the inner side (-X side) in the device width direction than the motor body 31a of the first motor 31. In this embodiment, the first encoder 37 is provided on the inner side of the right side frame 33. This allows the first encoder 37 to be arranged in a space-saving manner in the device width direction, and therefore the size of the scanner 1 in the width direction can be made compact.

[0055] Next, a description will be given of a drive mechanism using the second motor 32. In this embodiment, the second motor 32 is a drive source for the transport drive roller 23 that constitutes the transport roller 20. The second motor 32 is a DC motor similar to the first motor 31, and is configured to include a motor main body 32a and a motor output shaft 32b extending from the motor main body 32a, as shown in Fig. 6. The second motor 32 is disposed with the axial direction of the motor output shaft 32b of the second motor 32 aligned with the device width direction (X-axis direction). The second motor 32 has a motor body 32a fixed to a left side frame 34 (FIG. 11) provided on the left side (-X side) when viewed from the front side of the device.

[0056] A seventh transmission gear 51 serving as a "second transmission mechanism" for transmitting the power of the motor is connected to the motor output shaft 32b of the second motor 32, and the seventh transmission gear 51 is attached so as to be positioned outside (on the -X side) in the device width direction relative to the motor body 32a. In this embodiment, the seventh transmission gear 51 is positioned outside the left side frame 34.

[0057] The power of the second motor 32 is configured to be transmitted from a seventh transmission gear 51 provided on the motor output shaft 32b to an eighth transmission gear 52 via a timing belt 53. In the second motor 32, the power is also transmitted from the seventh transmission gear 51 to the eighth transmission gear 52 via the timing belt 53, so that the power can be transmitted with less influence of vibration of the second motor 32.

[0058] The timing belt 53 is configured to be given a predetermined tension by a belt tension mechanism 80 (FIG. 18). The belt tension mechanism 80 is configured to include a driven pulley 81 that is rotatable following the rotating timing belt 53, a pulley holder 82 that supports the driven pulley 81 and is movable in the directions of the double arrows +C and −C in FIG. 18, and a tension spring 83 that serves as a biasing member that applies tension to the timing belt 53. The tension spring 83 pulls the driven pulley 81 in the +C direction, applying tension to the timing belt 53.

[0059] A boss 84 is provided on the left side frame 34, and a groove 85 provided in the pulley holder 82 is fitted into this boss 84, thereby guiding the pulley holder 82 in the directions of the double arrows indicated by +C and -C. The pulley holder 82 is also fixed in its mounting position with a screw 86.

[0060] The eighth transmission gear 52 is a drive gear that receives power from the second motor 32 via the seventh transmission gear 51 and rotates the rotation shaft 54. The eighth transmission gear 52 is attached to one end (the end 54a on the -X side) of the rotation shaft 54 ​​of the transport drive roller 23, so that the power of the second motor 32 is transmitted to the transport drive roller 23. In other words, the eighth transmission gear 52 is a "one-side holder" of the rotation shaft 54 ​​that is attached to one axial end 54a of the rotation shaft 54 ​​of the transport drive roller 23, on the side where the second motor 32 is arranged.

[0061] A D-cut portion 55 (FIG. 15) having a cross section formed by cutting a portion of a circle is formed on one end 54a of the rotating shaft 54, and a D-cut hole 56 (FIG. 16) having a shape corresponding to the D-cut portion 55 and into which the D-cut portion 55 is press-fitted is formed on the eighth transmission gear 52 serving as the "one-side holder." The D-cut portion 55 of the rotating shaft 54 ​​is press-fitted into the D-cut hole 56 of the eighth transmission gear 52, and the rotating shaft 54 ​​is attached to the eighth transmission gear 52, thereby suppressing or preventing the eighth transmission gear 52 from rotating together with the rotation of the rotating shaft 54. In FIG. 16, the rib 74 provided inside the D-cut hole 56 is a crushing rib that is crushed when the D-cut portion 55 of the rotary shaft 54 ​​is press-fitted.

[0062] The second motor 32 is also provided with a second scale 57 that rotates in response to the drive of the second motor 32, and a second encoder 58 (FIG. 9) that detects the amount of rotation of the second scale 57. The control unit 35 (FIG. 17) is configured to control the drive of the second motor 32 based on information detected by the second encoder 58. By controlling the drive of the second motor 32 based on information detected by the second encoder 58, it is possible to drive the transport drive roller 23 in accordance with the rotation status of the object to be driven, and to suppress transport disturbances when feeding paper.

[0063] In this embodiment, the second scale 57 of the second encoder 58 is provided outside the eighth transmission gear 52 and is configured to rotate integrally with the rotary shaft 54 ​​. More specifically, second scale 57 is attached to round press-fit holder 59 (FIG. 7) which is attached integrally to circular rotating shaft 54 ​​by press-fitting end 54b (FIGS. 7 and 11) on the +X side of circular rotating shaft 54 ​​into a circular hole. That is, round press-fit holder 59 is provided at end 54b on the other side in the axial direction of rotating shaft 54, relative to end 54a on one side where D-cut portion 55 is formed.

[0064] In order to achieve highly accurate transport by the transport drive roller 23 (transport roller 20), it is desirable that the second scale 57 of the second encoder 58 be provided so as to rotate integrally with the rotation shaft 54 ​​of the transport drive roller 23. On the other hand, if the attachment of the rotary shaft 54 ​​to the eighth transmission gear 52, which serves as a drive gear for rotating the rotary shaft 54, is achieved by press-fitting the D-cut portion 55 formed on one end 54a of the rotary shaft 54 ​​into the D-cut hole 56 of the eighth transmission gear 52, there is a risk that the eighth transmission gear 52 will become eccentric due to the press-fitting. Therefore, if the second scale 57 is provided on the eighth transmission gear 52, there is a risk that the second scale 57 will also become eccentric, making it impossible to accurately detect the rotation of the rotary shaft 54.

[0065] In this embodiment, the second scale 57 is provided on the round press-fit holder 59, which is a component other than the eighth transmission gear 52 into which the D-cut portion 55 is press-fitted, and is configured to rotate integrally with the rotating shaft 54. Therefore, the rotation of the rotating shaft 54 ​​can be detected with less influence of eccentricity, and highly accurate control of the transport drive roller 23 becomes possible. Furthermore, since the second scale 57 is attached to the round press-fit holder 59, into which the rotating shaft 54 ​​is press-fitted and attached integrally with the rotating shaft 54, the influence of the eccentricity in the eighth transmission gear 52, in which the D-cut portion 55 of the rotating shaft 54 ​​is press-fitted into the D-cut hole 56, is reduced, and the second scale 57 can be attached so as to rotate integrally with the rotating shaft 54.

[0066] Furthermore, the round press-fit holder 59 to which the second scale 57 of the second encoder 58 is attached is provided at the other axial end 54b of the rotating shaft 54, relative to one end 54a having a D-cut portion 55 press-fitted into the D-cut hole 56 of the eighth transmission gear 52. In other words, the eighth transmission gear 52 and the round press-fit holder 59 are provided on both sides of the rotating shaft 54, so the width of the device can be reduced compared to a configuration in which both the eighth transmission gear 52 and the round press-fit holder 59 are provided on the same side of the rotating shaft 54. This allows the scanner 1 to be made more compact.

[0067] In this embodiment, the second motor 32 is the drive source for the transport drive roller 23, and is also used as the drive source for the separation roller 14, the drive roller (discharge drive roller 27) of the discharge roller 22 as a "downstream transport roller" provided downstream of the transport roller 20, and the regulating unit 40. Each of the drive mechanisms will be described below.

[0068] First, the drive mechanism of the separation roller 14 will be described with reference to FIG. 11 . As described above, the transport drive roller 23 is driven to rotate by the power of the second motor 32. A ninth transmission gear 60 is provided on the rotation shaft 54 ​​of the transport drive roller 23, on the inner side (−X side) of the round press-fit holder 59. The ninth transmission gear 60 is engaged with a tenth transmission gear 61. Furthermore, the tenth transmission gear 61 is engaged with an eleventh transmission gear 63 included in a gear train 62 composed of multiple gears. Furthermore, a rotation shaft 64 connected to one gear of the gear train 62, a twelfth transmission gear 65 provided on the rotation shaft 64, a thirteenth transmission gear 66 engaged with the twelfth transmission gear 65, and a fourteenth transmission gear 67 engaged with the thirteenth transmission gear 66 are provided. The fourteenth transmission gear 67 is provided on the rotation shaft 68 of the separation roller 14. As described above, the power of the second motor 32 is transmitted to the separation roller 14 by the gear train from the seventh transmission gear 51 to the fourteenth transmission gear 67.

[0069] Furthermore, the separation roller 14 is provided in the upper unit 3, but in the drive mechanism of the separation roller 14, the components from the second motor 32 to the ninth transmission gear 60 provided on the rotation shaft 54 ​​of the transport drive roller 23 are provided in the lower unit 2, and the components from the tenth transmission gear 61 to the separation roller 14 are provided in the upper unit 3. When the upper unit 3 is opened relative to the lower unit 2 (Figure 12), the ninth transmission gear 60 on the lower unit 2 side and the tenth transmission gear 61 on the upper unit 3 side are separated, as shown in Figure 13.

[0070] Next, the drive mechanism of the discharge drive roller 27, which is the drive roller for the discharge roller 22, will be described with reference to FIG. A sixteenth transmission gear 72 is provided on an end 70a of the rotation shaft 70 of the discharge drive roller 27 on the +X side, which is the side where the second motor 32 is located in the device width direction. The sixteenth transmission gear 72 is engaged with a fifteenth transmission gear 71, which is engaged with an eighth transmission gear 52, which is a drive gear that rotates the rotation shaft 54 ​​of the transport drive roller 23. In other words, the power of the second motor 32 is transmitted to the sixteenth transmission gear 72 via the seventh transmission gear 51, the eighth transmission gear 52, and the fifteenth transmission gear 71, causing the rotation shaft 70 of the discharge drive roller 27 to rotate.

[0071] Next, the operation and drive mechanism of the regulating unit 40, which switches between a regulating state and an allowing state of the pressing unit 39, which presses the paper placed on the media loading section 11 toward the feed roller 13, to advance toward the feed roller 13, will be explained with reference to Figure 14. First, we will explain the operation of the regulating portion 40. The pressing unit 39 is provided so as to be able to advance and retreat relative to the feed roller 13, and is biased in a direction in which it advances relative to the feed roller 13 by a biasing means (not shown).

[0072] In addition, the regulating section 40 is arranged to be swingable around the swing axis 40a, and can be switched between a restricting state (upper diagram in Figure 14) in which the pressing unit 39 restricts the advancement of the pressing unit 39 toward the feed roller 13 and an allowing state (lower diagram in Figure 14) in which the pressing unit 39 is allowed to advance toward the feed roller 13 by a drive mechanism described later. In the restricted state, the restricting portion 40 supports the set document stack G as described above, and prevents the bottom document from contacting the feed roller 13 .

[0073] Meanwhile, the restricting portion 40 is formed with a recess 40b as an engaging portion, and when the restricting portion 40 is in the restricting state, the tip 38b of the flap 38 fits into the recess 40b as shown in the upper diagram of Fig. 14. In this state, the pressing unit 39 is pushed up by the restricting portion 40 via the flap 38 against the urging force of a urging means (not shown), and is maintained in a state separated from the feed roller 13. In this feed standby state, the pressing unit 39 is not pressing against the document stack G.

[0074] In addition, in this feeding standby state, the tip 38b of the flap 38 is inserted into the recess 40b of the restricting portion 40, so that the flap 38 is restricted from rotating about the swing shaft 38a, and the flap 38 maintains a blocking position that blocks the medium feeding path. In other words, the swinging movement is restricted so that the position cannot be changed. 14 shows a state in which the pressing unit 39 is separated from the feed roller 13, that is, a restricting state in which the restricting portion 40 restricts the pressing unit 39 from advancing toward the feed roller 13. The bottom diagram of FIG. 14 shows the opposite state in which the pressing unit 39 has advanced toward the feed roller 13, that is, a permissive state in which the pressing unit 39 is permitted to advance toward the feed roller 13. The flap 38 is biased by, for example, a coil spring (not shown) provided on the swing shaft 38a toward a shielding position (upper view in FIG. 14) in which the flap 38 shields the medium feeding path.

[0075] When feeding of the originals begins, the restricting portion 40 switches from the restricting state to the allowing state shown in the lower diagram of Figure 14, and the bottom original comes into contact with the feed roller 13. Then, the pressing unit 39 is no longer pushed upward by the restricting portion 40 via the flap 38, so that the pressing unit 39 advances toward the feed roller 13 by the biasing force of the biasing means (not shown), and presses the original stack G toward the feed roller 13.

[0076] When the feed roller 13 rotates, the lowermost document in contact with the feed roller 13 is sent downstream. The document sent downstream causes the flap 38 to switch to a position that opens the medium feed path, as shown in the lower diagram of Figure 14. In this way, the flap 38 stops the progress of the document stack G downstream in the feed standby state (upper diagram of Figure 14), but does not obstruct the feeding of the documents during paper feeding (lower diagram of Figure 14).

[0077] Next, the drive mechanism of the restriction portion 40 will be described. A 17th transmission gear 73 is engaged with the eighth transmission gear 52, which is the drive gear of the rotation shaft 54 ​​of the transport drive roller 23. A drive cam 76 of the regulating unit 40 (FIGS. 8 and 9) is provided on a rotation shaft 75 of the 17th transmission gear 73. A one-way clutch is provided on the 17th transmission gear 73, so that when the 8th transmission gear 52 rotates to rotate the transport drive roller 23 in the paper transport direction, that is, when the 8th transmission gear 52 rotates clockwise in FIG. 8, the rotation shaft 75 of the 17th transmission gear 73 does not rotate. At this time, the regulating unit 40 is in an allowable state (lower diagram in FIG. 14). On the other hand, when the eighth transmission gear 52 rotates in the opposite direction (counterclockwise in Figure 8) to the direction that rotates the transport drive roller 23 in the paper transport direction, the seventeenth transmission gear 73 rotates clockwise, and the drive cam 76 pushes the regulating section 40 upward, causing the regulating section 40 to switch from the permissive state (lower figure in Figure 14) to the regulating state (upper figure in Figure 14).

[0078] When the transport drive roller 23 is rotating in the paper transport direction, the rotation shaft 75 of the 17th transmission gear 73 does not rotate due to the one-way clutch provided in the 17th transmission gear 73. However, vibrations caused by the rotation of the 8th transmission gear 52 or the transport drive roller 23 may cause the rotation shaft 75 of the 17th transmission gear 73 to rattle, generating noise. To suppress this rattle, as shown in FIG. 18 , a tension spring 78 is attached between the rotation shaft 75 of the 17th transmission gear 73 and a hook portion 77 provided on the left side frame 34, and the rotation shaft 75 of the 17th transmission gear 73 is biased by the tension spring 78 in a direction intersecting the axial direction. In FIG. 18 , the 17th transmission gear 73 is not shown to make the rotation shaft 75 easier to see.

[0079] One possible means for suppressing rattle of the rotating shaft 75 is to provide a leaf spring or bushing at the bearing portion of the rotating shaft 75 to bias the rotating shaft 75 in the axial direction, but this is relatively difficult to install and is likely to increase the load on the rotation of the rotating shaft 75. However, a configuration in which tension spring 78 biases in a direction intersecting the axial direction of rotating shaft 75 has the advantages that the load of tension spring 78 required to suppress rattle of rotating shaft 75 is small, the load on rotation of rotating shaft 75 is not likely to increase, and installation is easy. Grease or the like can be used at the installation portion of tension spring 78 on the rotating shaft 75 side to reduce friction between rotating shaft 75 and tension spring 78 when rotating shaft 75.

[0080] In this embodiment, the first motor 31 may also be used as a drive source for other drive systems in addition to the feed roller 13. The second motor 32 may also be used as a drive source for other drive systems in addition to the transport roller 20, the separation roller 14, the discharge roller 22, and the regulating unit 40.

[0081] Furthermore, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and it goes without saying that these are also included in the scope of the present invention. [Explanation of symbols]

[0082] 1...Scanner (image reading device), 2...Lower unit, 3...Upper unit, 4...Paper support, 5...Paper output tray, 6...Feed slot, 7...Housing, 8...Discharge port, 9...Device main body, 10...Medium feeding device, 11...Medium mounting section, 12...edge guide, 13...feed roller, 14...separation roller, 15... auxiliary paper support, 20... transport roller, 21... image reading unit (reading unit), 22...Discharge roller (downstream transport roller), 23...Transport drive roller, 24...conveyance driven roller, 25...upper image reading sensor, 26...lower image reading sensor, 27...discharge drive roller, 28...discharge driven roller, 29a...lower guide surface, 29b...upper guide surface, 30...conveyance path, 31...first motor (first driving source), 31a...motor body, 31b...motor output shaft, 32...second motor (second driving source), 32a...motor body, 32b...motor output shaft, 33...right side frame, 34...left side frame, 35...control unit, 36...first scale, 37...first encoder, 38...flap, 39...pressure unit, 40...regulation portion, 41...first transmission gear (first transmission mechanism part), 42...second transmission gear, 43...Third transmission gear, 44...Fourth transmission gear, 45...Fifth transmission gear, 46...Sixth transmission gear, 47...Rotating shaft, 48...Rotating shaft, 49...Timing belt, 51... seventh transmission gear, 52... eighth transmission gear (second transmission mechanism part), 53... timing belt, 54... rotating shaft, 55... D-cut portion, 56... D-cut hole, 57...Second scale, 58...Second encoder, 59...round press-fit holder, 60...ninth transmission gear, 61...tenth transmission gear, 62...wheel train, 63...eleventh transmission gear, 64...rotating shaft, 65...twelfth transmission gear, 66... ​​13th transmission gear, 67... 14th transmission gear, 68... rotating shaft, 70...rotating shaft, 71...15th transmission gear, 72...16th transmission gear, 73...17th transmission gear, 74...rib, 75...rotating shaft, 76...driving cam, 77... hook portion, 78... tension spring, 80... belt tension mechanism, 81... driven pulley, 82... pulley holder, 83... tension spring, 84...Boss, 85...Groove, 86...Screw, P...Paper

Claims

1. a reading unit that reads the medium; a feeding roller provided in the medium feeding path, which feeds the medium placed on the medium placement unit toward the reading unit; a separation roller that is provided at a position facing the feed roller and that nips and separates the medium between the feed roller and the separation roller; a conveying roller provided downstream of the feed roller; a first motor that drives the feed roller; a second motor that drives the transport roller; a housing that includes the feed roller, the transport roller, the first motor, and the second motor therein; a plurality of transmission gears that rotate the separation roller; An image reading device comprising: The housing includes: a lower unit constituting a lower portion of the housing; an upper unit that opens and closes relative to the lower unit; Equipped with the first motor and the second motor are provided in the lower unit, and are provided at positions on both sides of a center portion of the housing in a width direction intersecting with a medium transport direction, the second motor is disposed on one side in the axial direction of a motor output shaft of the second motor, with the direction along the width direction being the axial direction of the motor output shaft of the second motor; a second transmission mechanism unit that is connected to the motor output shaft extending from a motor body of the second motor and transmits power of the second motor is attached so as to be located on one side in the axial direction of the motor body of the second motor; a first timing belt engaged with the second transmission mechanism; a belt tensioning mechanism that applies tension to the first timing belt; the belt tension mechanism includes a biasing member that applies tension to the first timing belt, the biasing member is attached so as to be located on one side of the motor body of the second motor in the axial direction; An image reading device characterized by:

2. 2. The image reading device according to claim 1, wherein the second motor is a DC motor. an encoder that detects the amount of rotation of a scale that rotates in response to the driving of the second motor; and a control unit that controls the driving of a corresponding motor based on the information detected by the encoder. An image reading device characterized by:

3. 3. The image reading device according to claim 1, a first transmission mechanism connected to a motor output shaft extending from a motor body of the first motor to transmit power of the first motor; A second timing belt is engaged with the first transmission mechanism. An image reading device characterized by:

4. 4. The image reading device according to claim 1, The biasing member is a tension spring. An image reading device characterized by:

Images