JP7606166B2 - Image reader - Google Patents

Description

The present invention relates to a media feeding device that feeds media, and an image reading device that is equipped with a media feeding device.

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 Japanese Patent Application Laid-Open No. 2003-233699, a stepping motor is used as a drive source for moving the optical system of a copying machine.

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

Here, if a stepping motor as in Patent Document 1 is used as the drive source of a medium feeding device that feeds a document to the image reading unit fixed inside the device, there is a risk that the transport of the document will be disturbed and the read image will be disturbed if a load fluctuation occurs in the drive source during scanning in the image reading unit. 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, the DC motor can perform feedback control in response to fluctuations in the load on the motor, and disturbances in the read image caused by fluctuations in the load on the motor can be easily suppressed.

Japanese Patent Application Publication No. 4-242234 JP 2014-60494 A Japanese Patent Application Publication No. 6-54132 JP 2006-10855 A

In scanners equipped with such media feeding devices, there is a need for users to make the device even smaller, but there is a limit to the space available for arranging a driving 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 able to be opened and closed relative to the lower unit for maintenance of the medium feeding device, etc., the weight balance when the upper unit is open is also important.

In view of the above problems, the 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. It is also to provide a medium feeding device or image reading device that can stably feed media.

To solve the above problem, the medium feeding device according to the first aspect of the present invention comprises a feed roller that feeds a medium placed on a medium placement section, a transport roller that is provided 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 contains the feed roller, the transport roller, the first drive source, and the second drive source, and the housing comprises a lower unit that constitutes the lower part of the housing, and an upper unit that opens and closes with respect to the lower unit, and the first drive source and the second drive source are provided on both sides of the center of the lower unit in the width direction that intersects with the media transport direction.

According to the present aspect, the first driving source and the second driving source are used as driving sources in the medium feeding device, and the first driving source and the second driving source are 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.
In addition, 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 stably installed.

The medium feeding device according to the second aspect of the present invention is characterized in that, in the first aspect, it comprises a separation roller that nips and separates the medium between the feed roller and the downstream transport roller, a downstream transport roller provided downstream of the transport roller, a pressing unit that is provided to be movable forward and backward with respect to the feed roller and presses the medium placed on the medium placement section toward the feed roller by advancing 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 transport roller, and the regulating unit are driven by the second driving source.

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

The medium feeding device according to the 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 device is equipped with a first encoder that detects the amount of rotation of a scale that rotates in response to the drive of the first drive source, a second encoder that detects the amount of rotation of a scale that rotates in response to the drive of the second drive source, and a control unit that controls the drive of the corresponding drive source based on information detected by the first encoder or the second encoder.

According to this aspect, the control unit controls the driving of the corresponding drive 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 disturbance in transport when the medium is transported by the first driving source or the second driving source.

The medium feeding device according to the fourth aspect of the present invention is characterized in that, in the third aspect, the first driving source is arranged with the direction along the width direction as 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 body of the first driving source and transmits the power of the motor is attached so as to be located 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.

According to this aspect, the first driving source is arranged with the axial direction of the motor output shaft aligned along the width direction, and a first transmission mechanism that is connected to the motor output shaft extending from the motor body and transmits the power of the motor 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 arranged in a space-saving manner in the width direction. This allows the size of the device in the width direction to be made compact.

The medium feeding device according to the fifth aspect of the present invention is the third or fourth aspect, in which the second driving source is arranged such that the direction along the width direction is the axial direction of the motor output shaft of the second driving source, a second transmission mechanism part that is connected to the motor output shaft of the second driving source extended from the motor body of the second driving source and transmits the power of the motor is attached so as to be located outside the motor body of the second driving source in the width direction, and a rotating shaft having the transport roller and a second transmission mechanism part that is an end of the rotating shaft on one side in the axial direction of the second driving source and is connected to the motor output shaft of the second driving source. and a one-side holder that is attached to the placement side and has a drive gear that receives power from the second drive source via the second transmission mechanism and rotates the rotating shaft, the one-side end of the rotating shaft is formed with a D-cut section having a cross section formed by cutting a part of a circle, the one-side holder is formed with a D-cut hole that is shaped to correspond to the D-cut section and into which the D-cut section is press-fitted, and the scale of the second encoder is provided outside the one-side holder and rotates integrally with the rotating shaft.

In order to realize 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, when the engagement between the rotating shaft and the one-side holder having a drive gear that rotates the rotating shaft is achieved by press-fitting the one-side end portion, which has a D-cut shape with a cross section of a circle with a part 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 together with the drive gear, and there is a risk that the rotation of the rotating shaft cannot be detected accurately.

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 influence of the eccentricity can be reduced and the rotation of the rotating shaft can be detected, enabling highly accurate control of the transport roller.

The sixth aspect of the present invention relates to a medium feeding device according to the fifth aspect, characterized in that the scale of the second encoder is attached to a round press-fit holder in which the rotating shaft is press-fitted into a circular hole and attached integrally to the rotating shaft.

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, so that the effect of the eccentricity in the one-side holder in which the rotating shaft is pressed into a D-cut hole is reduced, and the scale of the second encoder can be attached so as to rotate integrally with the rotating shaft.

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

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 with respect 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 that 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.

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

According to this aspect, the influence of vibrations of the first driving source or the second driving source can be reduced, and power from each driving source can be transmitted.

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

According to this aspect, in an image reading device that includes 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.

FIG. 1 is a perspective view showing a scanner according to the present invention. FIG. 4 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. 2 is a side cross-sectional view showing a feeding path in the scanner according to the present invention. FIG. 2 is a rear view of the main body of the scanner according to the present invention. FIG. 4 is a rear perspective view of the device main body on the side where a second driving source is arranged. FIG. 4 is a rear perspective view of the device main body on the side where a first driving source is arranged. FIG. FIG. 4 is a perspective view showing drive system components in the main body of the apparatus. FIG. 4 is a perspective view showing a drive mechanism for a feed roller. FIG. 4 is a perspective view showing a drive mechanism for the separation roller. FIG. 13 is a perspective view of the upper unit in an open state relative to the lower unit. FIG. 13 is a perspective view showing the portion B in FIG. 12 from a different angle. 6A to 6C are diagrams illustrating the operation of a restriction portion. FIG. FIG. FIG. 1 is a block diagram of a scanner according to the present invention. FIG. 13 is a perspective view showing a state in which a seventeenth transmission gear is removed from the side where the second driving source is arranged in the main body of the apparatus.

[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 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 driving source is arranged. FIG. 7 is a rear perspective view of the device body on the side where a first driving source is arranged. FIG. 8 is a side view of the device body.

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

<Scanner Overview>
A scanner 1 (FIG. 1) as an image reading device according to the present invention includes a housing 7 that constitutes a part of the external appearance of the device, and a device main body 9 provided within the housing 7. The device main body 9 includes a medium feeding device 10 that is one embodiment of the "medium feeding device" according to the present invention, and an image reading unit 21 (FIG. 4) that reads an image of a document fed by the medium feeding device 10.
The housing 7 is composed of a lower unit 2 that constitutes the lower part of the housing 7 , and an upper unit 3 that opens and closes relative to the lower unit 2 .

In the X-Y-Z coordinate system shown in each figure, the X direction is the device width direction and the paper width direction, and the Y direction is the paper transport direction. The Z direction is a direction that intersects with the Y direction and generally indicates a direction perpendicular to the surface of the paper being transported. The +Y direction side is the front side of the device, and the -Y direction side is the rear side of the device. The right side as viewed from the front side of the device is the +X direction, and the left side is the -X direction. The +Z direction is the upper side of the device (including the upper part, upper surface, etc.), and the -Z direction side is the lower side of the device (including the lower part, lower surface, etc.).
In addition, in the scanner 1, the paper P as a medium is transported in the +Y direction in each drawing. In the following, the direction in which the paper P is transported (the +Y direction side) is referred to as "downstream," and the opposite direction (the -Y direction side) is referred to as "upstream."

The upper unit 3 is attached to the lower unit 2 so that it can rotate about 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, and 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 paper jams.

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 "media support" that supports a document (hereinafter sometimes referred to as "paper P") as an example of a medium in the open state (see FIG. 2).

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 (Fig. 2) as shown in Fig. 1, or in a feeding state in which it rotates from the non-feeding state in Fig. 1 to the rear side of the device as shown in Fig. 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).

In addition, an auxiliary paper support 15 (Figures 2 and 3) is provided upstream of the paper support 4. The auxiliary paper support 15 is configured so that it can be stored in and pulled out of 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 transport direction is long.

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 towards the front side of the device. The paper output tray 5 can be stored in the bottom of the lower unit 2 (see Figure 1) or pulled out to the front side of the device (see Figure 2). In this embodiment, the paper output tray 5 is made up of multiple connected tray members, and the length of the paper that is pulled out from the outlet 8 can be adjusted depending on the length of the paper P to be discharged.

<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 unit 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.

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

The paper P is picked up by a feed roller 13 that is rotatably mounted on the lower unit 2 and fed downstream (+Y direction). Specifically, the feed roller 13 feeds the paper P downstream by rotating while contacting the surface of the paper P that faces the loading surface of the medium loading section 11. 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.

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 .

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 starts, 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. That is, contact with the feed roller 13 is prevented. The drive mechanism of the regulating portion 40 will be described in detail later.

When document feeding begins, the regulating portion 40 retreats downward, the bottom document in the document stack G comes into contact with the feed roller 13, and the flap 38 is in a swingable state (position switchable state). 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 takes a position that opens the medium feeding path.

A transport roller 20 is provided downstream of the feed roller 13. The transport roller 20 is configured with 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.

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, a surface that supports the paper P from below is referred to as a lower guide surface 29a, and a surface opposing 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 disposed so as to partially protrude from the lower guide surface 29a.

An image reading unit 21 serving as a “reading unit” that reads an image is provided downstream of the transport rollers 20 , 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 a contact image sensor module (CISM), for example.

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 outlet 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 and 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 .

<Regarding the medium 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) includes 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.

As shown in Figure 5, the first motor 31 and the second motor 32 are each arranged to be located on either side 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.
In addition, 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.

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 body 31a and a motor output shaft 31b extending from the motor 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 is attached by fixing a motor body 31a to a right side frame 33 (FIG. 7) provided on the right side (+X side) as viewed from the front side of the device. A left side frame 34 (FIG. 6) is provided on the left side (-X side) as viewed from the front side of the device.

A first transmission gear 41, which serves 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 is attached so as to be positioned outside (+X side) in the device width direction relative to the motor body 31a. In this embodiment, the first transmission gear 41 is positioned outside the right side frame 33 (see Figures 7 and 10).

As shown in FIG. 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 engages with the third transmission gear 43, which engages with the fourth transmission gear 44. The 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).

The fifth transmission gear 45 shown in FIG. 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 through a timing belt 49 while reducing the effects of vibration of the first motor 31.

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 information detected by the first encoder 37, the feed roller 13 can be driven in response to the rotational state of the driven object, and transport disturbances when feeding paper can be suppressed.

Here, the first encoder 37 is provided on the inside (-X side) of the motor body 31a of the first motor 31 in the device width direction. In this embodiment, the first encoder 37 is provided on the inside 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, making it possible to make the size of the scanner 1 in the width direction compact.

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 like the first motor 31, and is configured to include a motor body 32a and a motor output shaft 32b extending from the motor body 32a, as shown in Fig. 6. The second motor 32 is disposed such that the axial direction of the motor output shaft 32b of the second motor 32 is 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.

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

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.

The timing belt 53 is configured to be given a predetermined tension by a belt tension mechanism 80 (Figure 18). The belt tension mechanism 80 is configured to include a driven pulley 81 that can rotate following the rotating timing belt 53, a pulley holder 82 that supports the driven pulley 81 and can move in the directions of the double arrows indicated by +C and -C in Figure 18, and a tension spring 83 that acts 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.

The left side frame 34 is provided with a boss 84, into which a groove 85 in the pulley holder 82 fits, thereby guiding the pulley holder 82 in the directions indicated by the double arrows +C and -C. The pulley holder 82 is also fixed in its mounting position by a screw 86.

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 (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 rotating shaft 54 that is attached to one axial end 54 a of the rotating shaft 54 of the transport drive roller 23 on the side where the second motor 32 is arranged.

A D-cut portion 55 (FIG. 15) having a cross section obtained by cutting a part of a circle is formed at 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 in 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, whereby co-rotation of the eighth transmission gear 52 accompanying the rotation of the rotating shaft 54 can be suppressed or avoided.
In FIG. 16, a rib 74 provided on the inside of the D-cut hole 56 is a crushing rib that is crushed when the D-cut portion 55 of the rotating shaft 54 is press-fitted.

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 the information detected by the second encoder 58. By controlling the drive of the second motor 32 based on the information detected by the second encoder 58, the transport drive roller 23 can be driven in response to the rotational state of the driven object, and transport disturbances when feeding paper can be suppressed.

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 rotating shaft 54 .
More specifically, the second scale 57 is attached to a round press-fit holder 59 (FIG. 7) that is attached integrally to the rotating shaft by pressing an end 54b (FIGS. 7 and 11) on the +X side of the circular rotating shaft 54 into a circular hole. That is, the round press-fit holder 59 is provided at the end 54b on the other side in the axial direction of the rotating shaft 54 relative to the end 54a on one side where the D-cut portion 55 is formed.

In order to achieve highly accurate transport by the transport drive roller 23 (transport roller 20 ), it is desirable to provide the second scale 57 of the second encoder 58 so as to rotate integrally with the rotation shaft 54 of the transport drive roller 23 .
On the other hand, when the attachment of the rotating shaft 54 to the eighth transmission gear 52 as a drive gear for rotating the rotating shaft 54 is performed by press-fitting the D-cut portion 55 formed on one side end portion 54a of the rotating 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-fit. Therefore, if the second scale 57 is provided on the eighth transmission gear 52, the second scale 57 will also become eccentric, and there is a risk that the rotation of the rotating shaft 54 cannot be detected accurately.

In this embodiment, the second scale 57 is provided on a round press-fit holder 59, which is a component other than the eighth transmission gear 52 into which the D-cut portion 55 is pressed, and is configured to rotate integrally with the rotating shaft 54. Therefore, the influence of the eccentricity can be reduced and the rotation of the rotating shaft 54 can be detected, enabling highly precise control of the transport drive roller 23.
Furthermore, since the second scale 57 is attached to a round press-fit holder 59 in which the rotating shaft 54 is pressed into a circular hole and attached integrally to 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 pressed 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.

In addition, 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 that is 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.

In this embodiment, the second motor 32 is used as the drive source for the transport drive roller 23, as well as the drive source for the separation roller 14, the drive roller (discharge drive roller 27) of the discharge roller 22 as the "downstream transport roller" provided downstream of the transport roller 20, and the regulating unit 40. The respective drive mechanisms are described below.

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. The 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 the tenth transmission gear 61. Furthermore, the tenth transmission gear 61 is engaged with the eleventh transmission gear 63 included in the gear train 62 composed of a plurality of 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 .

In addition, 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 in an open state 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.

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, so that the rotation shaft 70 of the discharge drive roller 27 rotates.

Next, the operation and drive mechanism of the regulating section 40 that switches between a regulating state and a allowing state of the pressing unit 39, which presses the paper placed on the medium loading section 11 toward the feed roller 13, advancing toward the feed roller 13 will be described with reference to Figure 14.
First, a description will be given of the operation of the regulating portion 40. The pressing unit 39 is provided so as to be movable toward and away from the feed roller 13, and is biased in a direction in which it advances toward the feed roller 13 by a biasing means (not shown).

In addition, the regulating portion 40 is arranged to be swingable around the swing axis 40a, and can be switched between a regulating state (upper part of Figure 14) in which the pressing unit 39 is urged forward relative to the feed roller 13 and an allowing state (lower part of Figure 14) in which the pressing unit 39 is allowed to urge forward relative to the feed roller 13 by a drive mechanism described later.
In the regulated state, the regulating portion 40 supports the set document stack G as described above, and prevents the bottom document from contacting the feed roller 13 .

Meanwhile, the restricting portion 40 is formed with a recess 40b as an engagement 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 apart from the feed roller 13. In this feeding standby state, the pressing unit 39 is not pressing the document stack G.

In addition, in this feeding standby state, the tip 38b of the flap 38 fits into the recess 40b of the regulating portion 40, so that the flap 38 is restricted from rotating about the swing shaft 38a and maintains a blocking position that blocks the medium feeding path. In other words, the swinging motion 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, i.e., a restricting state in which the restricting portion 40 restricts the pressing unit 39 from advancing toward the feed roller 13. The lower diagram of Fig. 14 shows the opposite state in which the pressing unit 39 has advanced toward the feed roller 13, i.e., an allowing state in which the pressing unit 39 is allowed to advance toward the feed roller 13.
The flap 38 is biased toward a blocking position (upper view in FIG. 14) blocking the medium feeding path by, for example, a coil spring (not shown) provided on the swing shaft 38a.

When feeding of the originals begins, the regulating section 40 switches from the regulating state to the permitting state shown in the lower diagram of FIG. 14, and the bottom original comes into contact with the feed roller 13. This causes the pressing unit 39 to no longer be pushed upward by the regulating section 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.

When the feed roller 13 rotates, the lowermost document in contact with the feed roller 13 is sent downstream. The flap 38 switches to a position that opens the medium feed path as shown in the lower diagram of Figure 14 due to the document being sent downstream. In this way, the flap 38 stops the downstream progress of the document stack G in the feed standby state (upper diagram of Figure 14), but does not impede the feeding of documents when paper is being fed (lower diagram of Figure 14).

Next, the drive mechanism of the restriction portion 40 will be described.
A 17th transmission gear 73 is engaged with the 8th transmission gear 52, which is a drive gear of the rotation shaft 54 of the transport drive roller 23. A drive cam 76 (FIGS. 8 and 9) of the regulating unit 40 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, and the rotation shaft 75 of the 17th transmission gear 73 is configured not to rotate when the 8th transmission gear 52 rotates to rotate the transport drive roller 23 in the paper transport direction, i.e., when the 8th transmission gear 52 rotates clockwise in FIG. 8. 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 to the direction in which the transport drive roller 23 rotates in the paper transport direction (counterclockwise in Figure 8), the 17th transmission gear 73 rotates clockwise, and the drive cam 76 presses the regulating portion 40 upward, switching the regulating portion 40 from the permissive state (lower figure in Figure 14) to the regulated state (upper figure in Figure 14).

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

One possible means for suppressing wobble of the rotating shaft 75 is to provide, for example, a leaf spring or a bush at the bearing portion of the rotating shaft 75 to bias the rotating shaft 75 in the axial direction; however, this is relatively difficult to install and tends to increase the load on the rotation of the rotating shaft 75.
However, the configuration in which the tension spring 78 biases the rotating shaft 75 in a direction intersecting the axial direction thereof is advantageous in that the load of the tension spring 78 required to suppress rattling of the rotating shaft 75 is small, the load on the rotation of the rotating shaft 75 is not likely to increase, and installation is easy. Grease or the like can be used at the attachment portion of the tension spring 78 on the rotating shaft 75 side to reduce friction between the rotating shaft 75 and the tension spring 78 when the rotating shaft 75 rotates.

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, separation roller 14, discharge roller 22, and regulating unit 40.

In addition, the present invention is not limited to the above-mentioned embodiment, 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 within the scope of the present invention.

1...scanner (image reading device), 2...lower unit, 3...upper unit,
4...paper support, 5...paper output tray, 6...feed port, 7...casing,
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...conveying 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: pressing unit, 40: restricting 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...rotary shaft, 65...twelfth transmission gear,
66... thirteenth transmission gear, 67... fourteenth transmission gear, 68... rotating shaft,
70: Rotating shaft, 71: 15th transmission gear, 72: 16th transmission gear,
73...17th transmission gear, 74...rib, 75...rotation 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 (5)

A reading unit that reads the medium;
a feeding roller provided in a medium feeding path for feeding the medium placed on the medium placement unit toward the reading unit;
a separation roller that is provided at a position opposite to the feed roller and that nips and separates the medium between the feed roller and the separation roller;
A transport 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 including the feed roller, the transport roller, the first motor, and the second motor therein;
A plurality of transmission gears for rotating 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 a medium transport direction,
The plurality of transmission gears include
A lower transmission gear provided in the lower unit;
an upper transmission gear provided in the upper unit and engaged with the lower transmission gear;
Including,
The second motor is
When the upper unit is in an open state relative to the lower unit, power is not output to the upper transmission gear that is not engaged with the lower transmission gear,
When the upper unit is in a closed state relative to the lower unit, power is output to the upper transmission gear that is engaged with the lower transmission gear.
1. An image reading apparatus comprising: 2. The image reading device according to claim 1 , wherein the second motor is a DC motor.
an encoder that detects an amount of rotation of a scale that rotates in response to driving of the second motor;
A control unit that controls driving of a corresponding motor based on information detected by the encoder.
1. An image reading apparatus comprising: 3. The image reading apparatus 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 timing belt is engaged with the first transmission mechanism.
1. An image reading apparatus comprising: 4. The image reading apparatus according to claim 1,
The second motor is disposed such that a direction along the width direction is an axial direction of a motor output shaft of the second motor, and a second transmission mechanism part that is connected to the motor output shaft extending from a motor body of the second motor and transmits power of the motor is attached so as to be located outside the motor body of the second motor in the width direction.
1. An image reading apparatus comprising: 5. The image reading apparatus according to claim 4,
A timing belt is engaged with the second transmission mechanism.
1. An image reading apparatus comprising:

Images