Media transport device, image reading device

Abstract

In a configuration in which foreign matter adhering to the detection unit is removed by the flow of gas, the foreign matter is effectively removed from the detection unit. [Solution] The media transport device comprises a guide member for guiding the transported media, a detection unit positioned opposite the guide member, and a flow path forming unit that forms a flow space between itself and the guide member through which gas can flow. The flow space is a space through which the gas taken in from the ventilation unit passes through the detection unit to the exhaust unit, and in the flow space, the flow velocity of the gas at the detection unit is greater than or equal to the flow velocity of the gas at the ventilation unit.

Description

Technical Field

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[0001] The present invention relates to a medium conveyance device for conveying a medium and an image reading device including the same.

Background Art

[0002] The document feeder described in Patent Document 1 includes a housing, a guide member attached to the housing for guiding a document conveyed through a document conveyance path, and a sound collecting unit provided in a space between the housing and the guide member. The document feeder further includes a ventilation path that communicates the inside and outside of the space between the housing and the guide member to send an air current to the sound collecting unit to clean the sound collecting unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The ventilation path described in Patent Document 1 is not designed from the viewpoint of increasing the flow velocity of the gas near the sound collecting unit, and there is a risk that the flow velocity of the gas near the sound collecting unit becomes slower than the flow velocity of the gas at the ventilation port. There is room for improvement from the viewpoint of appropriately cleaning the sound collecting unit.

Means for Solving the Problems

[0005] The medium conveyance device of the present invention for solving the above problems includes a guide member for guiding a conveyed medium, a detection unit disposed to face the guide member, and a flow path forming unit that forms a flow space in which gas can flow between the guide member and the detection unit. The flow space is a space through which the gas taken in from the ventilation unit reaches the exhaust unit through the detection unit, and the flow velocity of the gas at the detection unit in the flow space is not less than the flow velocity of the gas at the ventilation unit. Furthermore, the image reading device of the present invention is characterized by comprising the media transport device and a reading unit that reads the media transported by the media transport device. [Brief explanation of the drawing]

[0006] [Figure 1] A diagram showing the media transport path in an image reading device. [Figure 2] External perspective view of the image reading device with the opening / closing unit omitted. [Figure 3] Figure 2 shows an enlarged perspective view of the area around the separation roller. [Figure 4] This diagram shows the state after removing the cover member and separation roller from the state shown in Figure 3. [Figure 5] This diagram shows the state after removing the guide member from the state shown in Figure 4. [Figure 6] A cross-sectional view showing the guide member, base member, and microphone cut at the entrance location. [Figure 7] A cross-sectional view showing the guide member, base member, and microphone cut at the entrance location. [Modes for carrying out the invention]

[0007] The present invention will be described in general terms below. A media transport device according to the first embodiment comprises a guide member for guiding a medium to be transported, a detection unit positioned opposite the guide member, and a flow path forming unit that forms a flow space between itself and the guide member through which gas can flow, wherein the flow space is a space through which the gas taken in from a ventilation unit passes through the detection unit to an exhaust unit, and the flow velocity of the gas in the detection unit in the flow space is greater than or equal to the flow velocity of the gas in the ventilation unit. Furthermore, it is sufficient that, at least in theoretical terms when pressure loss is ignored, the gas flow velocity in the detection unit is equal to or greater than the gas flow velocity in the ventilation unit.

[0008] According to this embodiment, since the gas flow velocity in the detection unit in the flow space is greater than or equal to the gas flow velocity in the ventilation unit, the decrease in the gas flow velocity in the detection unit is suppressed, and the detection unit can be effectively cleaned.

[0009] The second embodiment is an embodiment dependent on the first embodiment, characterized in that the cross-sectional area of ​​the fluid space in the detection unit is less than or equal to the cross-sectional area of ​​the fluid space in the ventilation unit. According to this embodiment, since the cross-sectional area of ​​the fluid space in the detection unit is less than or equal to the cross-sectional area of ​​the fluid space in the ventilation unit, the flow velocity of the gas in the detection unit can be set to be greater than or equal to the flow velocity of the gas in the ventilation unit, and the detection unit can be effectively cleaned.

[0010] A third embodiment is an embodiment dependent on the second embodiment, characterized in that the cross-sectional area of ​​the fluid space in the detection unit is smaller than the cross-sectional area of ​​the fluid space in the ventilation unit. According to this embodiment, since the cross-sectional area of ​​the flow space in the detection unit is smaller than the cross-sectional area of ​​the flow space in the ventilation unit, the gas flow velocity in the detection unit can be made faster than the gas flow velocity in the ventilation unit, and the detection unit can be effectively cleaned.

[0011] A fourth embodiment is an embodiment dependent on the third embodiment, characterized in that the cross-sectional area of ​​the fluid space at a first position between the detection unit and the ventilation unit is greater than the cross-sectional area of ​​the fluid space in the detection unit and smaller than the cross-sectional area of ​​the fluid space at a second position between the ventilation unit and the first position, and the cross-sectional area of ​​the fluid space at the second position is smaller than the cross-sectional area of ​​the fluid space in the ventilation unit.

[0012] According to this embodiment, since the cross-sectional area decreases from the ventilation section toward the detection section, the flow velocity of the gas in the detection section can be increased efficiently, and the detection section can be effectively cleaned.

[0013] The fifth aspect is an aspect dependent on the first aspect, wherein the flow path forming portion has a first portion located upstream of the detection portion in the flow direction of the gas, and a second portion located downstream of the first portion in the flow direction and upstream of the detection portion, and the first portion and the second portion are connected so as to guide the gas downstream in the flow direction.

[0014] According to this aspect, since the first portion and the second portion are connected so as to guide the gas downstream in the flow direction, the fluidity of the gas from the ventilation portion toward the detection portion is ensured, the flow velocity of the gas in the detection portion can be ensured, and a decrease in the flow velocity of the gas in the detection portion can be suppressed. That is, the flow velocity of the gas in the detection portion can be made not less than the flow velocity of the gas in the ventilation portion, and the detection portion can be effectively cleaned. Note that this aspect is not limited to the first aspect, and may be dependent on any of the second to fourth aspects.

[0015] The sixth aspect is an aspect dependent on the first aspect, wherein an upstream end of the flow path forming portion in the flow direction of the gas faces the ventilation portion, and the gas flowing in from the ventilation portion is divided into a gas flowing from the upstream end of the flow path forming portion toward the flow space and a gas flowing toward a space different from the flow space, and the flow velocity of the gas flowing from the upstream end of the flow path forming portion toward the flow space is faster than the flow velocity of the gas flowing from the upstream end of the flow path forming portion toward a space different from the flow space.

[0016] According to this aspect, by branching the gas in two directions at the upstream end of the flow path forming portion, the flow velocity of the gas toward the detection portion is increased, and thus the detection portion can be effectively cleaned. Note that this aspect is not limited to the first aspect, and may be dependent on any of the second to fifth aspects.

[0017] The seventh aspect is an aspect dependent on the sixth aspect, wherein the flow path forming portion has an airfoil cross-sectional shape. According to this aspect, since the flow path forming portion has an airfoil cross-sectional shape, a configuration for bifurcating the gas in two directions at the upstream end of the flow path forming portion and increasing the flow velocity of the gas toward the detection portion can be easily obtained.

[0018] An eighth aspect is an aspect dependent on the seventh aspect, wherein the upstream end of the flow path forming portion is curved so as to be convex toward the upstream in the flow direction. According to this aspect, in the configuration in which the upstream end of the flow path forming portion is curved so as to be convex toward the upstream in the flow direction, the operational effects of the sixth or seventh aspect described above can be obtained. Note that this aspect is not limited to the seventh aspect described above, and may also be dependent on the sixth aspect.

[0019] A ninth aspect is an aspect dependent on the eighth aspect, wherein the downstream end of the flow path forming portion in the flow direction has a shape that tapers toward the downstream in the flow direction. According to this aspect, since the downstream end of the flow path forming portion in the flow direction has a shape that tapers toward the downstream in the flow direction, the flow velocity of the gas toward the detection portion can be effectively increased, and the detection portion can be effectively cleaned.

[0020] A tenth aspect is an aspect dependent on the seventh aspect, wherein the flow path forming portion includes an upstream member located upstream of the detection portion in the flow direction and a downstream member located downstream of the detection portion in the flow direction, and an upstream end of the upstream member in the flow direction is curved so as to be convex toward the upstream in the flow direction, and a downstream end of the downstream member in the flow direction has a shape that tapers toward the downstream in the flow direction.

[0021] According to this aspect, since the downstream end of the downstream member in the flow direction has a shape that tapers toward the downstream in the flow direction, the flow velocity of the gas toward the detection portion can be effectively increased, and the detection portion can be effectively cleaned. Furthermore, since the path forming section is composed of multiple members, including the upstream member and the downstream member, the size of each member can be suppressed and each member can be easily formed. Furthermore, this embodiment is not limited to the seventh embodiment described above, but may be dependent on any of the sixth, eighth, or ninth embodiments described above.

[0022] The eleventh embodiment is an embodiment dependent on any of the first to tenth embodiments, characterized in that the ventilation section is provided upstream of the detection section in the direction of transport of the medium. According to this embodiment, since the ventilation section is provided upstream of the detection section in the direction of transport of the medium, the gas flows in from the ventilation section due to the airflow accompanying the transport of the medium, thereby effectively cleaning the detection section.

[0023] The twelfth embodiment is an embodiment dependent on any of the first to tenth embodiments, characterized in that the exhaust unit is provided downstream of the detection unit in the direction of transport of the medium. According to this embodiment, since the exhaust unit is provided downstream of the detection unit in the direction of transport of the medium, the detection unit can be effectively cleaned when gas flow occurs in the flow space due to the airflow accompanying the transport of the medium. Furthermore, this embodiment is not limited to any of the first to tenth embodiments described above, but may be dependent on the eleventh embodiment described above.

[0024] The thirteenth embodiment is an embodiment dependent on any of the first to tenth embodiments, wherein the exhaust unit is provided outside the width of the medium in the width direction intersecting the medium transport direction. According to this embodiment, in a configuration in which the exhaust section is provided outside the width of the medium in the width direction intersecting the medium transport direction, any of the effects of the first to ten embodiments described above can be obtained. Furthermore, this embodiment is not limited to any of the first to tenth embodiments described above, but may be dependent on either the eleventh or twelfth embodiment described above.

[0025] The 14th aspect is an aspect dependent on any of the 1st to 10th aspects, characterized in that an opening is formed in the flow path forming section, and a receiving section for accommodating foreign matter is further provided below the opening.

[0026] According to this embodiment, since a containment section for accommodating foreign matter is further provided below the opening, it is possible to suppress the scattering of foreign matter removed from the detection section into the device and causing adverse effects. Furthermore, this embodiment is not limited to any of the first to tenth embodiments described above, but may be dependent on any of the eleventh to thirteenth embodiments described above.

[0027] The 15th aspect is an aspect dependent on any of the first to tenth aspects, further comprising an airflow generating section for supplying the gas to the ventilation section. According to this embodiment, the detection unit can be effectively cleaned because the ventilation unit is further provided with an airflow generating unit that supplies the gas. Furthermore, this embodiment is not limited to any of the first to tenth embodiments described above, but may be dependent on any of the eleventh to fourteenth embodiments described above.

[0028] The sixteenth aspect is an aspect dependent on any of the first to tenth aspects, characterized in that the detection unit is a sensor capable of detecting the medium being transported. According to this embodiment, in a configuration in which the detection unit is a sensor capable of detecting the transported medium, deterioration of the detection accuracy of the medium can be suppressed. Furthermore, this embodiment is not limited to any of the embodiments 1 to 10 described above, but may be dependent on any of the embodiments 11 to 15 described above.

[0029] The 17th embodiment is an embodiment dependent on any of the 1st to 10th embodiments, characterized in that the detection unit has a microphone for collecting sound generated in the medium transport path. According to this embodiment, in a configuration in which the detection unit has a microphone for collecting sound generated in the media transport path, deterioration of sound collection accuracy can be suppressed. Furthermore, this embodiment is not limited to any of the embodiments 1 to 10 described above, but may be dependent on any of the embodiments 11 to 15 described above.

[0030] The 18th aspect is an aspect dependent on the 17th aspect, characterized in that the guide member has an inlet for guiding sound generated in the medium transport path to the detection unit, and the inlet is located downstream of the detection unit in the medium transport direction. According to this embodiment, since the inlet is located downstream of the detection unit in the direction of transport of the medium, it is possible to suppress foreign matter that enters through the inlet from adhering to the detection unit.

[0031] The 19th aspect is an aspect dependent on the 18th aspect, characterized in that the exhaust section is located downstream of the inlet in the conveying direction. According to this embodiment, since the exhaust section is located downstream of the inlet in the transport direction, foreign matter adhering to the inlet can be discharged from the exhaust section.

[0032] The image reading device according to the 20th embodiment is characterized by comprising a media transport device according to any of the first to tenth embodiments, and a reading unit for reading the media transported by the media transport device. According to this embodiment, the effects and advantages of the first to ten embodiments described above can be obtained in the image reading device. In this embodiment, the media transport device may be any of the media transport devices described in the 11th to 19th embodiments described above.

[0033] The present invention will be described in detail below. Note that the XYZ coordinate system shown in each figure is a Cartesian coordinate system, where the direction of the arrow is the +X direction and the opposite direction is the - direction. The X-axis direction is the direction that intersects the media transport direction, i.e., the media width direction and also the device width direction. The Y-axis direction is the depth direction of the device. Of the Y-axis directions, the +Y direction is from the back of the device towards the front, and the -Y direction is from the front of the device towards the back. The Z-axis direction is vertical and corresponds to the height of the device. Within the Z-axis direction, the +Z direction is upward and the -Z direction is downward.

[0034] The image reading device 1 of this embodiment is a scanner capable of reading images from a medium, and is a sheet-feed type scanner that reads images from a medium while transporting it. Here, the image on the medium refers to what is visually recorded on the medium, such as text, figures, tables, pictures, photographs, etc. The medium is not limited to sheets, but also includes cards, booklets, etc. Furthermore, the image reading device 1 may also be referred to as the media transport device 2 from the standpoint of transporting the medium. In this case, the image reading device 1 comprises the media transport device 2 and the first reading unit 25 and the second reading unit 26, which will be described later.

[0035] As shown in Figure 1, the image reading device 1 is equipped with a transport path T for transporting the medium. The transport path T is formed inside the device body 3. In Figure 1, the transport path T is shown as a dashed line. Along the transport path T, the medium P is transported linearly along the -Y direction, then inverted upwards and discharged in the +Y direction. The configuration of the transport path T is described below along the direction in which the medium is transported. In the following, the direction in which the medium is transported will be referred to as "downstream," and the opposite direction as "upstream."

[0036] At the very upstream end of the transport path T, there is a media support section 9 for supporting the medium. The media support section 9 supports the medium horizontally. Of course, the media support section 9 may also support the medium in an inclined position. The symbol P indicates the medium supported by the media support section 9. Hereafter, the medium will be referred to as medium P, with the symbol P appended to it. The media support unit 9 moves up and down vertically while maintaining its posture using a power source (not shown). As the media support unit 9 rises, the media P supported by the media support unit 9 can come into contact with the pick roller 11.

[0037] The pick roller 11 is driven by a motor (not shown) and feeds the medium P supported by the medium support section 9 downstream. In the transport path T, a feed roller 12 is provided downstream of the pick roller 11. The feed roller 12 is driven by a motor (not shown) and feeds the medium P downstream. The pick roller 11 and the feeding roller 12 constitute a feeding unit 10 that feeds the medium P from the medium support unit 9.

[0038] A separation roller 13 is provided opposite the feed roller 12. The separation roller 13 separates the medium P by nipping it between itself and the feed roller 12. The separation roller 13 is driven by a motor (not shown) in the direction of returning the medium P upstream. A torque limiter (not shown) is interposed in the power transmission path between the separation roller 13 and the motor (not shown). When only one medium P is present between the feed roller 12 and the separation roller 13, the separation roller 13 rotates in contact with the medium P due to the action of the torque limiter. When multiple medium P are present between the feed roller 12 and the separation roller 13, the separation roller 13 rotates in the direction of returning the medium P upstream by the power of the motor (not shown), thereby preventing double feeding. Alternatively, a separation pad may be used instead of the separation roller 13. The pick roller 11, feeding roller 12, and separation roller 13 described above are located at the center of the media width direction, or at positions symmetrical to the center.

[0039] Next, downstream of the feed roller 12 in the transport path T, a first transport roller pair 15, a second transport roller pair 16, and a third transport roller pair 17 are provided in this order toward the downstream direction. The transport path T extends horizontally from the pick roller 11 to the third transport roller pair 17. The first transport roller pair 15, the second transport roller pair 16, and the third transport roller pair 17 are each driven by a motor (not shown) at least one of their rollers. The first transport roller pair 15, the second transport roller pair 16, and the third transport roller pair 17 transport the medium P downstream.

[0040] Reference numeral 15a denotes a transport roller provided on the lower side of the first transport roller pair 15. A detection unit 40 is provided between the separation roller 13 and the transport roller 15a. In this embodiment, the detection unit 40 consists of a microphone that collects sound generated in the transport path T. Reference numeral 33 denotes a guide member that guides the medium P between the separation roller 13 and the transport roller 15a. The detection unit 40 is positioned below the guide member 33 and facing the guide member 33.

[0041] Between the second pair of transport rollers 16 and the third pair of transport rollers 17, the first reading unit 25 is provided on the upper side with respect to the transport path T. Also, between the second pair of transport rollers 16 and the third pair of transport rollers 17, the second reading unit 26 is provided on the lower side with respect to the transport path T. Between the second pair of transport rollers 16 and the third pair of transport rollers 17, the first reading unit 25 and the second reading unit 26 are provided facing each other across the transport path T. Of course, the first reading unit 25 and the second reading unit 26 may be provided in offset positions in the transport direction. The first reading unit 25 reads the image of the first surface of the medium P. The second reading unit 26 reads the image of the second surface of the medium P, which is opposite to the first surface. The first reading unit 25 and the second reading unit 26 are, for example, CIS (Contact It is configured to include an Image Sensor.

[0042] The transport path T curves upward and reverses downstream of the third transport roller pair 17. In this curved and reversing section, the fourth transport roller pair 18, the fifth transport roller pair 19, and the sixth transport roller pair 20 are provided in this order toward the downstream direction. At least one roller of the fourth transport roller pair 18, the fifth transport roller pair 19, and the sixth transport roller pair 20 is driven by a motor (not shown). The fourth transport roller pair 18 and the fifth transport roller pair 19 transport the medium P downstream. The sixth transport roller pair 20 discharges the medium P in the +Y direction. The medium P discharged by the sixth conveyor roller pair 20 is supported by the discharge receiving section 23. The discharge receiving section 23 supports the medium P in an inclined position. Of course, the discharge receiving section 23 may also support the medium P in a horizontal position.

[0043] The series of operations, including the raising and lowering of the media support unit 9, the rotation of each roller, and the reading of the image on the media P by the first reading unit 25 and the second reading unit 26, are controlled by a control unit (not shown). This control unit includes a CPU, non-volatile memory, etc. (not shown). Programs and parameters for performing various controls are stored in the non-volatile memory.

[0044] Next, the main body of the device 3 is equipped with an opening / closing unit 5 that can be opened and closed. When the opening / closing unit 5 is closed, it forms a part of the transport path T. When the opening / closing unit 5 is open relative to the main body of the device 3, it opens a part of the transport path T as shown in Figure 2. Note that the opening / closing unit 5 in the open state is not shown in Figure 2. The opening / closing unit 5 may be detachably mounted relative to the main body of the device 3. In particular, the opening / closing unit 5 is equipped with a discharge receiving section 23, a pick roller 11, and a feeding roller 12. When the opening / closing unit 5 is opened, the feeding roller 12 separates from the separation roller 13, and the separation roller 13 is exposed as shown in Figure 2.

[0045] Figure 3 is an enlarged view of the area around the separation roller 13 in Figure 2. The separation roller 13 is exposed through an opening 14a provided in the cover member 14. The cover member 14 is provided so as to be openable and closable relative to the guide member 33. Of the two separation rollers 13 provided in the width direction, an inlet 33a is provided downstream in the conveying direction of the separation roller 13 in the -X direction. The inlet 33a will be explained in more detail later. Figure 4 shows the state after removing the cover member 14 and the separation roller 13 from the state shown in Figure 3. In Figure 4, reference numeral 34 denotes a ventilation section. The ventilation section 34 is the part that takes in gas and is formed between the guide member 33 and the base member 31. Reference numeral 31a denotes an upstream forming section formed on the base member 31.

[0046] Figure 5 shows the state in which the guide member 33 has been further removed from the state in Figure 4, exposing the base member 31. The upstream forming section 31a is formed to be recessed from the upper surface of the base member 31, and the symbol Wa is the width of the upstream forming section 31a. Downstream of the upstream forming section 31a in the transport direction, the detection section 40, the opening 31c, and the downstream forming section 31b are provided in this order along the transport direction. The detection section 40 is fixed to the base member 31.

[0047] As shown in Figure 6, a fluid space 36 is formed between the guide member 33 and the base member 31. The detection unit 40, which is a microphone, has a substrate 41, a microphone element 43, and an outer casing member 44. The microphone element 43 converts the sound collected at the sound collection unit 42 into an electrical signal. The sound collection unit 42 is a hole. The control unit (not shown) of the image reading device 1 can detect that a jam has occurred in the transport path T based on the signal received from the detection unit 40. The sound generated in the transport path T reaches the sound collection unit 42 through the inlet 33a formed in the guide member 33.

[0048] The exterior member 44 that forms the outer casing of the detection unit 40 can be made of an elastic material, such as silicone rubber. Furthermore, a dustproof material such as woven fabric or non-woven fabric may be provided between the sound collection unit 42 and the microphone element 43.

[0049] Next, in the conveying direction, the upstream end 33b of the guide member 33 is sloped downward toward the upstream direction of conveying, and a ventilation section 34 is formed between this upstream end 33b and the upstream forming section 31a. The dashed arrows indicate the flow direction of the gas taken into the flow space 36 from the ventilation section 34. The gas taken into the flow space 36 from the ventilation section 34 passes over the upper surface of the detection section 40 and then flows in the -Y direction. When the gas taken into the flow space 36 from the ventilation section 34 passes over the upper surface of the detection section 40, foreign matter du adhering to the upper surface of the detection section 40 is removed.

[0050] Since an opening 31c is formed between the detection unit 40 and the downstream forming unit 31b, downstream of the detection unit 40 in the flow direction, an airflow fa along the lower surface of the guide member 33 and an airflow fb directed downward are generated. Foreign matter du blown away by the airflow between the detection unit 40 and the guide member 33 is easily carried downward and collected in the collection unit 39 by the airflow fb. The collection unit 39 is a tray-shaped part located below the opening 31c. The collection unit 39 may be provided in a removable manner. By providing such a collection unit 39, it is possible to suppress the scattering of foreign matter removed from the detection unit 40 into the device and causing adverse effects. The outlet of the flow space 36 formed between the downstream forming section 31b and the guide member 33 becomes the exhaust section 35. In this embodiment, the exhaust section 35 faces the space where the conveying rollers 15a are arranged. In this embodiment, the exhaust section 35 does not communicate with the outside of the device, but it may communicate with the outside of the device.

[0051] In this embodiment, the upstream forming section 31a, the exterior member 44 constituting the detection section 40, and the downstream forming section 31b constitute a flow path forming section 30 that forms a flow space 36 through which gas can flow between them and the guide member 33.

[0052] In this embodiment, the flow space 36 narrows from the ventilation section 34 toward the detection section 40. In this embodiment, the widthwise size Wa of the flow space 36 (see Figure 5) is constant at least from the ventilation section 34 toward the detection section 40. In contrast, the gap between the guide member 33 and the flow path forming section 30 decreases toward the downstream direction of flow, as shown in Figure 6. That is, the cross-sectional area of ​​the flow space 36 at the detection section 40 is less than or equal to the cross-sectional area of ​​the flow space 36 at the ventilation section 34.

[0053] As a result, the gas flow velocity in the detection unit 40 in the flow space 36 becomes greater than or equal to the gas flow velocity in the ventilation unit 34. Consequently, the decrease in gas flow velocity in the detection unit 40 is suppressed, and the detection unit 40 can be effectively cleaned. Furthermore, even when the gas flow velocity in the detection unit 40 in the flow space 36 is equal to the gas flow velocity in the ventilation unit 34, the detection unit 40 can be cleaned more effectively compared to a configuration in which the gas flow velocity in the detection unit 40 in the flow space 36 is lower than the gas flow velocity in the ventilation unit 34.

[0054] Furthermore, the inflow of gas from the ventilation section 34 into the flow space 36 may be achieved by the user using an air duster or the like to spray air, or by installing a fan (not shown) at the bottom of the ventilation section 34 and generating airflow with this fan. Such a fan is an example of an airflow generating unit that sends gas into the ventilation section 34.

[0055] Furthermore, in this embodiment, the cross-sectional area of ​​the fluid space 36 in the detection unit 40 is less than or equal to the cross-sectional area of ​​the fluid space 36 in the ventilation unit 34. More specifically, the cross-sectional area of ​​the fluid space 36 in the detection unit 40 is smaller than the cross-sectional area of ​​the fluid space 36 in the ventilation unit 34. This allows the gas flow velocity in the detection unit 40 to be greater than or equal to the gas flow velocity in the ventilation unit 34, thereby effectively cleaning the detection unit 40. In this embodiment, the above-mentioned cross-sectional area relationship is achieved by keeping the widthwise size Wa of the flow space 36 (see Figure 5) constant while decreasing the gap between the guide member 33 and the flow path forming section 30 downstream in the flow direction. However, in addition to decreasing the gap between the guide member 33 and the flow path forming section 30 downstream in the flow direction, or alternatively, the widthwise size Wa of the flow space 36 may be decreased downstream in the flow direction.

[0056] Furthermore, in this embodiment, the cross-sectional area of ​​the fluid space 36 at the first position Q1 between the detection unit 40 and the ventilation unit 34 is larger than the cross-sectional area of ​​the fluid space 36 in the detection unit 40, and smaller than the cross-sectional area of ​​the fluid space 36 at the second position Q2 between the ventilation unit 34 and the first position Q1. The cross-sectional area of ​​the fluid space 36 at the second position Q2 is smaller than the cross-sectional area of ​​the fluid space 36 in the ventilation unit 34. In this configuration, where the cross-sectional area of ​​the flow space 36 decreases from the ventilation section 34 towards the detection section 40, the gas flow velocity in the detection section 40 can be increased efficiently, allowing the detection section 40 to be cleaned effectively. However, even if the cross-sectional area of ​​the flow space 36 temporarily increases from the ventilation section 34 toward the detection section 40, it is sufficient if the gas flow velocity in the detection section 40 is greater than or equal to the gas flow velocity in the ventilation section 34.

[0057] Furthermore, the flow path forming section 30 has an upstream forming section 31a, which is a first section located upstream of the detection section 40 in the direction of gas flow, and an outer casing member 44, which is a second section located downstream of the upstream forming section 31a in the direction of gas flow. The upstream forming section 31a and the outer casing member 44 are connected in such a way that they guide the gas downstream in the direction of flow. In other words, the area where the upper surface of the upstream forming section 31a and the upper surface of the exterior member 44 meet is flush with the surface without any steps. This ensures the fluidity of the gas from the ventilation section 34 towards the detection section 40, ensuring the gas flow velocity in the detection section 40, and allowing the detection section 40 to be cleaned effectively. Furthermore, the portion where the upper surface of the upstream forming portion 31a and the upper surface of the exterior member 44 connect is not necessarily flush, but may have a certain degree of step difference. In this case, the upper surface of the exterior member 44 may be higher or lower than the upper surface of the upstream forming portion 31a at the connecting portion. Furthermore, it is preferable that there is no gap between the upstream forming portion 31a and the exterior member 44, but a certain degree of gap may be present between the upstream forming portion 31a and the exterior member 44.

[0058] Next, other embodiments of the flow path forming section will be described with reference to Figure 7. Note that components identical to those already described will be denoted by the same reference numerals, and redundant explanations will be avoided. The flow path forming section 30A shown in Figure 7 comprises an upstream forming section 31f provided on the base member 31, an exterior member 44 constituting the detection section 40, and a downstream forming section 31g provided on the base member 31. The upstream forming section 31f is an example of an upstream member located upstream of the detection section 40, and the downstream forming section 31g is an example of a downstream member located downstream of the detection section 40.

[0059] The upstream end of the flow channel forming section 30A faces the ventilation section 34 in the direction of gas flow. The gas flowing in from the ventilation section 34 is divided into gas flowing towards the flow space 36 from the upstream end of the flow channel forming section 30 and gas flowing towards a space different from the flow space 36. The symbol fu indicates the flow direction of the gas flowing towards the flow space 36 from the upstream end of the flow channel forming section 30. The symbol fd indicates the flow direction of the gas flowing towards a space different from the flow space 36 from the upstream end of the flow channel forming section 30. In this embodiment, the space different from the flow space 36 is the space below the flow channel forming section 30A.

[0060] In this embodiment, the flow path forming section 30A has an airfoil cross-sectional shape. As a result, the gas flowing in the flow direction fu has a higher flow velocity than the gas flowing in the flow direction fd. Consequently, the detection section 40 can be effectively cleaned. In this embodiment, since the flow path forming section 30A has an airfoil cross-sectional shape, a configuration can be easily obtained in which the gas is branched into two directions at the upstream end of the flow path forming section 30A, thereby increasing the flow velocity of the gas toward the detection section 40. However, the flow path forming section 30A is not limited to an airfoil cross-sectional shape; any shape that generates lift is acceptable. In other words, it is sufficient if the gas is branched into two directions at the upstream end of the flow path forming section 30A, and the flow velocity of the gas heading towards the detection section 40 is increased.

[0061] Furthermore, the upstream end of the flow channel forming section 30A, specifically the upstream end of the upstream forming section 31f, is curved so as to be convex toward the upstream direction in the flow direction. Furthermore, the downstream end of the flow channel forming section 30A, specifically the downstream end of the downstream forming section 31g, has a shape that tapers towards the downstream direction of flow. As a result, the flow velocity of the gas toward the detection unit 40 can be effectively increased, and the detection unit 40 can be effectively cleaned.

[0062] Furthermore, the flow path forming section 30A includes an upstream forming section 31f located upstream of the detection section 40 in the direction of gas flow, and a downstream forming section 31g located downstream of the detection section 40 in the direction of gas flow. Since the flow path forming section 30A is composed of multiple members in this way, the size of each member can be suppressed and each member can be easily formed. However, the airfoil cross-sectional shape may be formed from multiple members as in this embodiment, or from a single member. Furthermore, a housing section 39, as described with reference to Figure 6, may be provided at the lower part of the flow path forming section 30A, particularly at the lower part of the downstream end of the downstream forming section 31g.

[0063] Next, we will describe the configuration and effects common to each embodiment shown in Figures 6 and 7. First, the ventilation section 34 is located upstream of the detection section 40 in the direction of transport of the medium P. As a result, gas flows in from the ventilation section 34 due to the airflow accompanying the transport of the medium P, effectively cleaning the detection section 40. In each of the above embodiments, the foreign matter du removed from the detection unit 40 by the gas supplied from the ventilation unit 34 flows downstream of the detection unit 40. Here, the foreign matter du in the flow space 36 is also carried away by the airflow generated as the medium P is transported in the transport path T, as described above. Therefore, even if the foreign matter du removed from the detection unit 40 is carried away by the airflow generated in the transport path T, it is unlikely that the foreign matter du will reattach to the detection unit 40, which is located upstream of the removed foreign matter du in the transport direction.

[0064] Next, the exhaust unit 35 is located downstream of the detection unit 40 in the direction of transport of the medium P. This allows the detection unit 40 to be effectively cleaned when gas flow occurs in the flow space 36 due to the airflow accompanying the transport of the medium P.

[0065] Furthermore, the guide member 33 has an inlet 33a formed therein to guide sound generated in the transport path T to the sound collection unit 42. The inlet 33a is located downstream of the detection unit 40 in the transport direction of the medium P. This prevents foreign matter that enters through the inlet 33a from adhering to the detection unit 40. If the position of the inlet 33a is offset from the position of the detection unit 40, it becomes more difficult for foreign matter that enters through the inlet 33a to reach the detection unit 40. In addition, even if air is injected into the interior from the inlet 33a, damage to the detection unit 40 due to this air injection can be suppressed. Furthermore, even if the inlet 33a is located at the position of the detection unit 40 in the transport direction of the medium P, the above-described effects can be obtained if it is offset in the width direction. Furthermore, the inlet 33a may also serve as the exhaust section 35. Furthermore, the inlet 33a may be provided outside the width of the medium P in the width direction intersecting the transport direction of the medium P.

[0066] Furthermore, the exhaust section 35 is located downstream of the inlet 33a in the conveying direction. This allows foreign matter adhering to the inlet 33a to be discharged from the exhaust section 35. Furthermore, by positioning the exhaust section 35 downstream in the transport direction from the sound collection section 42 and the inlet 33a, foreign matter entering from the exhaust section 35 is less likely to adhere to the sound collection section 42 and the inlet 33a.

[0067] Next, we will describe variations of each of the above embodiments. First, the exhaust section 35 may be provided outside the width of the medium P in the width direction intersecting the transport direction of the medium P. For example, if the exhaust section 35 is formed in the guide member 33 in the same way as the inlet 33a, providing the exhaust section 35 outside the width of the medium P in the width direction can prevent the medium P from getting caught in the exhaust section 35. In this embodiment, the ventilation section 34, detection section 40, inlet 33a, and exhaust section 35 are located approximately at the same position in the width direction and are arranged in a nearly straight line along the transport direction. This ensures that the gas supplied from the ventilation section 34 blows away foreign matter near the detection section 40, and the gas discharged from the exhaust section 35 flows smoothly.

[0068] In this embodiment, the detection unit 40 is composed of a microphone that collects sound generated in the transport path T, and the deterioration of sound collection accuracy is suppressed by blowing away foreign matter attached to the detection unit 40 with the airflow described above, but the detection unit 40 is not limited to this. For example, the detection unit 40 may be a sensor capable of detecting the transported medium P. In this case, the deterioration of detection accuracy of the medium P can be suppressed by blowing away foreign matter attached to the detection unit 40 with the airflow described above. Examples of such sensors include optical sensors and ultrasonic sensors.

[0069] Furthermore, the configuration in which the detection unit 40 is cleaned by the flow path forming units 30 and 30A described above was applied to an image reading device in the above embodiment, but it may also be applied to a recording device that records on a medium. Furthermore, it goes without saying that the present invention is not limited to the embodiments and modifications described above, and various modifications are possible within the scope of the invention as described in the claims, and these are also included within the scope of the present invention. [Explanation of Symbols]

[0070] 1…Image reading device, 2…Media transport device, 3…Device body, 5…Opening / closing unit, 9…Media support part, 10…Feeding part, 11…Pick roller, 12…Feeding roller, 13…Separation roller, 14…Cover member, 15…First transport roller pair, 16…Second transport roller pair, 17…Third transport roller pair, 18…Fourth transport roller pair, 19…Fifth transport roller pair, 20…Sixth transport roller pair, 23…Discharge receiving part, 25…First reading part, 26…Second reading part, 30…Flow path forming part, 31…Base member, 31a…Upstream forming part, 31b…Downstream forming part, 31c…Opening, 31f…Upstream forming part, 31g…Downstream forming part, 33…Guide member, 33a…Inlet, 33b…Upstream end, 34…Ventilation part, 35…Exhaust part, 36…Flow space, 39…Storage part, 40...Detection unit, 41...Substrate, 42...Sound collection unit, 43...Microphone element, 44...Exterior component, P...Medium, Q1...First position, Q2...Second position, T...Transport path

Claims

1. A guide member that guides the transported medium, A detection unit is positioned opposite the guide member, A flow channel forming section that forms a flow space between itself and the guide member through which gas can flow, Equipped with, The aforementioned flow space is the space through which the gas taken in from the ventilation section passes through the detection section and reaches the exhaust section. In the aforementioned flow space, the gas flow velocity in the detection unit is greater than or equal to the gas flow velocity in the ventilation unit. A media transport device characterized by the following features.

2. In the media transport device according to claim 1, The cross-sectional area of ​​the fluid space in the detection unit is less than or equal to the cross-sectional area of ​​the fluid space in the ventilation unit. A media transport device characterized by the following features.

3. In the medium transport device according to claim 2, The cross-sectional area of ​​the fluid space in the detection unit is smaller than the cross-sectional area of ​​the fluid space in the ventilation unit. A media transport device characterized by the following features.

4. In the media transport device according to claim 3, The cross-sectional area of ​​the flow space at the first position between the detection unit and the ventilation unit is greater than the cross-sectional area of ​​the flow space in the detection unit, and smaller than the cross-sectional area of ​​the flow space at the second position between the ventilation unit and the first position. The cross-sectional area of ​​the fluid space at the second position is smaller than the cross-sectional area of ​​the fluid space in the ventilation section. A media transport device characterized by the following features.

5. In the media transport device according to claim 1, The aforementioned flow channel forming section is In the flow direction of the gas, the first part located upstream of the detection unit, A second portion located downstream of the first portion and upstream of the detection unit in the flow direction, It has, The first and second portions are connected in such a way as to guide the gas downstream in the flow direction. A media transport device characterized by the following features.

6. In the media transport device according to claim 1, The flow channel forming portion has an upstream end in the direction of gas flow that faces the ventilation portion. The gas flowing in from the ventilation section is divided into gas that flows from the upstream end of the flow path forming section toward the flow space and gas that flows toward a space different from the flow space. The flow velocity of the gas moving from the upstream end of the flow channel forming section toward the flow space is faster than the flow velocity of the gas moving from the upstream end of the flow channel forming section toward a space different from the flow space. A media transport device characterized by the following features.

7. In the media transport device according to claim 6, The aforementioned flow channel forming portion has an airfoil cross-sectional shape. A media transport device characterized by the following features.

8. In the media transport device according to claim 7, The upstream end of the flow channel forming section is curved so as to be convex toward the upstream direction in the flow direction. A media transport device characterized by the following features.

9. In the media transport device according to claim 8, The downstream end of the flow channel forming portion in the flow direction has a shape that tapers toward the downstream in the flow direction. A media transport device characterized by the following features.

10. In the media transport device according to claim 7, The aforementioned flow channel forming section is In the flow direction, the upstream member located upstream of the detection unit, In the flow direction, the downstream member located downstream of the detection unit, It has, The upstream end of the upstream member in the flow direction is curved so as to be convex toward the upstream direction in the flow direction. The downstream end of the downstream member in the flow direction has a shape that tapers toward the downstream direction in the flow direction. A media transport device characterized by the following features.

11. In a media transport device according to any one of claims 1 to 10, The ventilation section is provided upstream of the detection section in the direction of transport of the medium. A media transport device characterized by the following features.

12. In a media transport device according to any one of claims 1 to 10, The exhaust unit is provided downstream of the detection unit in the direction of transport of the medium. A media transport device characterized by the following features.

13. In a media transport device according to any one of claims 1 to 10, The exhaust section is provided outside the width of the medium in the width direction intersecting the medium transport direction. A media transport device characterized by the following features.

14. In a media transport device according to any one of claims 1 to 10, An opening is formed in the aforementioned flow channel forming section. Below the opening, there is further a storage section for accommodating foreign objects. A media transport device characterized by the following features.

15. In a media transport device according to any one of claims 1 to 10, The ventilation section further comprises an airflow generating section for supplying the gas. A media transport device characterized by the following features.

16. In a media transport device according to any one of claims 1 to 10, The detection unit is a sensor capable of detecting the medium being transported. A media transport device characterized by the following features.

17. In a media transport device according to any one of claims 1 to 10, The detection unit has a microphone that collects sound generated in the media transport path. A media transport device characterized by the following features.

18. In the media transport device according to claim 17, The guide member has an inlet for guiding sound generated in the medium transport path to the detection unit. The aforementioned inlet is located downstream of the detection unit in the media transport direction. A media transport device characterized by the following features.

19. In the media transport device according to claim 18, The exhaust section is located downstream of the inlet in the conveying direction. A media transport device characterized by the following features.

20. The media transport device according to any one of claims 1 to 10, A reading unit that reads the medium transported by the aforementioned medium transport device, An image reading device equipped with [unclear].

Images