Image reading device and image forming apparatus

Abstract

To provide an image reading device that can avoid a situation where a scan sensor is pressed by a conveying system against the inner wall of the image reading device, and an image forming apparatus.SOLUTION: An image reading device 100 comprises a placement part 11, a scan sensor 21, and a conveying system 25. The conveying system 25 reciprocates the scan sensor 21. The conveying system 25 has a motor 26, a conveying belt 28, and a transmission mechanism 60. The motor 26 drives to generate motive power. The conveying belt 28 operates along with the drive of the motor 26 and conveys the scan sensor 21. The transmission mechanism 60 transmits the motive power generated by the drive of the motor 26 to the conveying belt 28 to actuate the conveying belt 28. When a load acting on the conveying belt 28 from the motor 26 through the transmission mechanism 60 exceeds a threshold, the transmission mechanism 60 stops the transmission of the motive power to the conveying belt 28.SELECTED DRAWING: Figure 7B

Description

Technical Field

[0001] The present invention relates to an image reading device and an image forming device.

Background Art

[0002] Generally, as an image reading device for reading a document as an image, there is known an image reading device including a scan sensor disposed below a contact glass of a document table and a conveyance system for reciprocally moving the scan sensor. In this image reading device, reading processing of the document is performed by the scan sensor conveyed along the document by the conveyance system.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in such an image reading device, when the control unit loses the reference position of the reading process of the scan sensor or loses the end position of the reading process, etc., there is a risk that the conveyance system presses the scan sensor against the inner wall of the image reading device, leading to a failure.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide an image reading device and an image forming device capable of avoiding the scan sensor being pressed against the inner wall of the image reading device by the conveyance system.

Means for Solving the Problems

[0006] An image reading apparatus according to an aspect of the present invention includes a placement unit, a scan sensor, and a conveyance system. On the upper surface of the placement unit, a document to be read is placed. The scan sensor is disposed below the placement unit and is used for reading an image of the document. The conveyance system reciprocates the scan sensor. The conveyance system includes a drive source, a conveyance belt, and a transmission mechanism. The drive source generates power when driven. The conveyance belt operates in accordance with the driving of the drive source to convey the scan sensor. The transmission mechanism transmits the power generated by the driving of the drive source to the conveyance belt to operate the conveyance belt. When the load acting on the conveyance belt from the drive source via the transmission mechanism exceeds a threshold value, the transmission mechanism stops transmitting power to the conveyance belt.

[0007] An image forming apparatus according to an aspect of the present invention includes the image reading apparatus described above and an image forming unit. The image forming unit forms an image corresponding to the image read by the scan sensor on a recording medium.

Advantages of the Invention

[0008] According to the present invention, it is possible to avoid the scan sensor being pressed against the inner wall of the image reading apparatus by the conveyance system.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7A

Figure 7B

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of an image reading apparatus and an image forming apparatus according to the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and the description will not be repeated.

[0011] First, with reference to Fig. 1, an image forming apparatus 200 according to an embodiment of the present invention will be described. Fig. 1 is a schematic perspective view of an image forming apparatus 200 according to an embodiment. The image forming apparatus 200 is, for example, a multifunction device having a printer function, a scanner function, and a copy function. The image forming apparatus 200 may have a facsimile function. In the present embodiment, the image forming apparatus 200 forms an image by an electrophotographic method.

[0012] As shown in Fig. 1, in the present embodiment, the image forming apparatus 200 includes an image reading apparatus 100 and an image forming unit 110.

[0013] The image reading apparatus 100 is disposed above the image forming unit 110. The image reading apparatus 100 includes a document table 10, a cover 30, a stock cover 33, and a document conveyance unit 90. For ease of understanding, in Fig. 1, the document conveyance unit 90 is shown by a two-dot chain line.

[0014] The document table 10 is disposed above the image forming unit 110. The document table 10 has a substantially rectangular parallelepiped shape. A document is placed on the document table 10.

[0015] The cover 30 has a thin substantially rectangular parallelepiped shape. The cover 30 is disposed above the platen 10. The cover 30 is openable and closable with respect to the platen 10. In the present embodiment, the cover 30 is attached to the platen 10 at the rear side of the platen 10 and freely rotates about a rotation axis located at the rear end portion of the platen 10. Note that the cover 30 may be attached to the platen 10 at the left end portion of the platen 10 and freely rotate about a rotation axis located at the left end portion of the platen 10.

[0016] The document conveyance unit 90 is disposed on the upper surface 35 of the cover 30. In the present embodiment, the document conveyance unit 90 is integrally formed with the cover 30. The document conveyance unit 90 is also called an automatic document feeder or ADF (Auto Document Feeder).

[0017] The stock cover 33 is disposed on the upper surface 35 of the cover 30. Further, the stock cover 33 faces a storage area 35a which is a part of the upper surface 35 of the cover 30. A part of the stock cover 33 is located inside the document conveyance unit 90.

[0018] The stock cover 33 and the storage area 35a constitute a storage portion 50. That is, the image reading apparatus 100 includes the storage portion 50. The storage portion 50 has an opening 50h. The opening 50h is located at the front side of the storage portion 50. A user can take in and out an object to be stored through the opening 50h. That is, the user can store, for example, an object to be stored inside the storage portion 50. The object to be stored is, for example, a document before or after reading, or an object other than a document (for example, a personal item of the user).

[0019] The rear side of the stock cover 33 is closed. Therefore, when the cover 30 is opened with respect to the platen 10, it is possible to prevent an object to be stored accommodated in the stock cover 33 from falling to the rear side of the image forming apparatus 200.

[0020] The image reading device 100 reads a document, for example, using the document conveyance unit 90. The document conveyance unit 90 conveys the document after reading to the upper surface 33u of the stock cover 33. In this specification, the document conveyed by the document conveyance unit 90 may be referred to as a conveyed document. That is, the conveyed document conveyed by the document conveyance unit 90 is placed on the upper surface 33u of the stock cover 33.

[0021] The image forming unit 110 forms an image on a recording medium. The image forming unit 110 forms, for example, an image corresponding to the image read by the reading unit 20 (see FIG. 3) of the image reading device 100 on the recording medium.

[0022] The recording medium is, for example, paper. In the present embodiment, the image forming unit 110 includes an exposure device, a charging device, a photosensitive drum, a developing device, a cleaning device, a transfer device, and a fixing device.

[0023] Next, the image forming apparatus 200 will be described in more detail with reference to FIG. 2. FIG. 2 is a block diagram of the image forming apparatus 200 shown in FIG. 1. The image forming apparatus 200 further includes a control unit 70, a storage unit 80, a reading unit 20, an input / output unit 40, an open / close sensor 52, and a human presence sensor 54.

[0024] Typically, the control unit 70 is disposed inside the image forming apparatus 200. The control unit 70 includes an arithmetic element. The arithmetic element includes a processor. For example, the processor includes a Central Processing Unit (CPU). The processor may include an Application Specific Integrated Circuit (ASIC).

[0025] The storage unit 80 stores various types of data, control programs, and various application programs. The storage unit 80 is composed of, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), and / or a Solid State Drive (SSD). The storage unit 80 may include an external memory. The external memory is a removable medium. The storage unit 80 may include, as an external memory, for example, a USB (Universal Serial Bus) memory and / or an SD (Secure Digital) card.

[0026] The control unit 70 controls the operations of each component of the image forming apparatus 200 by executing the control program stored in the storage unit 80. Specifically, the control unit 70 controls the reading unit 20, the input / output unit 40, the open / close sensor 52, the human presence sensor 54, the storage unit 80, the document conveyance unit 90, and the image forming unit 110.

[0027] The control unit 70 realizes the functions of the generation unit 71, the sheet number determination unit 73, the end determination unit 74, and the counting unit 75 by executing the control program. That is, the control unit 70 includes the generation unit 71, the sheet number determination unit 73, the end determination unit 74, and the counting unit 75.

[0028] The generation unit 71 generates document image data based on the reading result of the reading unit 20. That is, the generation unit 71 generates document image data based on the image read by the scan sensor 21.

[0029] The sheet number determination unit 73 determines whether the number of documents input to the input unit 42 matches the number of read documents counted by the counting unit 75.

[0030] The end determination unit 74 determines whether the work including the scan process has ended. Further, the end determination unit 74 may determine that the work has ended when it is detected that a person has left the image reading apparatus 100.

[0031] The counting unit 75 counts the number of sheets read, which indicates the number of manuscript sheets read.

[0032] Next, with reference to FIG. 3, the details of the image reading apparatus 100 will be described. FIG. 3 is a schematic perspective view of the image reading apparatus 100 shown in FIG. 1. In order to avoid complication of the drawing, in FIG. 3, the description of the document conveyance unit 90 and the image forming unit 110 is omitted.

[0033] The document table 10 includes a contact glass 11, a light transmitting part 12, and a reading slit 13. In the document table 10, the contact glass 11, the light transmitting part 12, and the reading slit 13 are located apart from each other. For example, the contact glass 11 is located on the front side of the light transmitting part 12. Also, the reading slit 13 is located on the left side of the contact glass 11 and the light transmitting part 12. The contact glass 11 is an example of the "placement part".

[0034] The contact glass 11 is disposed on the upper surface of the document table 10. The contact glass 11 has light transmissivity. On the contact glass 11, the manuscript to be read is placed.

[0035] The light transmitting part 12 is disposed on the upper surface of the document table 10. The light transmitting part 12 has light transmissivity. The light transmitting part 12 is preferably transparent. The light transmitting part 12 is disposed, for example, on the rear side of the contact glass 11.

[0036] The reading slit 13 is disposed on the upper surface of the document table 10. The reading slit 13 has light transmissivity. The reading slit 13 is used to read the conveyed manuscript conveyed by the document conveyance unit 90.

[0037] The reading unit 20 is disposed inside the document table 10. The reading unit 20 reads the image of the manuscript placed on the contact glass 11 by the user.

[0038] The cover 30 is openable and closable with respect to the platen 10. That is, the cover 30 opens and closes with respect to the contact glass 11 included in the platen 10. For example, the cover 30 may be provided with a support member that enables the opening and closing of the cover 30. When the cover 30 is in the "open state", the upper surface of the platen 10 is exposed. On the other hand, when the cover 30 is in the "closed state", the upper surface of the platen 10 is covered by the cover 30.

[0039] The cover 30 has a light-shielding portion 31 and a light-transmitting portion 32. The light-shielding portion 31 blocks light. The light-shielding portion 31 is formed of, for example, a colored resin.

[0040] The light-transmitting portion 32 has light-transmitting properties. The light-transmitting portion 32 is formed of, for example, a light-transmitting resin material such as an acrylic resin. Therefore, light incident from one side of the light-transmitting portion 32 exits from the other side. Note that the light-transmitting portion 32 may be glass or a cavity as long as it has light-transmitting properties.

[0041] The light-transmitting portion 32 is surrounded by the light-shielding portion 31. When the cover 30 is closed with respect to the platen 10, the light-transmitting portion 32 is arranged so as to overlap with the light-transmitting portion 12 of the platen 10. Typically, the length of the light-transmitting portion 32 in the left-right direction and the length in the front-rear direction are substantially equal to the length of the light-transmitting portion 12 in the left-right direction and the length in the front-rear direction, respectively. Note that the positions of the light-transmitting portion 32 and the light-transmitting portion 12 are determined according to, for example, the arrangement position of the document conveyance unit 90.

[0042] The input / output unit 40 is arranged on the front side of the side portion of the platen 10. The user inputs an instruction via the input / output unit 40. The input / output unit 40 receives the user's instruction. In the present embodiment, the user's instruction includes the type of job and the number of document sheets indicating the number of document sheets.

[0043] For example, when the user inputs an instruction to start a scan job via the input / output unit 40, the reading unit 20 reads the document and reads the image of the document. Note that in this specification, the image data indicating the document may be described as "document image data".

[0044] In addition, the input / output unit 40 outputs information to the user. For example, the input / output unit 40 notifies the user of the necessary information.

[0045] The input / output unit 40 includes a display unit 41 and an input unit 42. The display unit 41 displays an operation screen or the results of various processes. The display unit 41 has a display. For example, the display includes a liquid crystal display or an organic EL display.

[0046] The input unit 42 includes, for example, various keys for instructing the type and content of a job. The input unit 42 includes a keyboard and a mouse. Alternatively, the input unit 42 may include a touch sensor. Note that the display unit 41 and the input unit 42 may be an integrated touch panel.

[0047] The open / close sensor 52 is attached to the document table 10. In the present embodiment, the open / close sensor 52 is attached to a region of the upper surface of the document table 10 that overlaps with the cover 30 when the cover 30 is closed. More specifically, the open / close sensor 52 is disposed on the same surface as the contact glass 11.

[0048] The open / close sensor 52 detects the open / closed state of the cover 30. That is, the open / close sensor 52 detects the "open state" or "closed state" of the cover 30. For example, the open / close sensor 52 includes a light emitting unit and a light receiving unit. The light emitting unit faces upward. When the cover 30 is closed with respect to the document table 10, the light emitted from the light emitting unit is reflected by the cover 30 and received by the light receiving unit. The open / close sensor 52 detects the "open state" or "closed state" of the cover 30 based on the amount of light received by the light receiving unit.

[0049] The open / close sensor 52 is, for example, a proximity sensor. The open / close sensor 52 outputs a detection signal indicating the open / closed state of the cover 30 to the control unit 70. For example, the detection signal indicates whether the cover 30 is in the "open state" or the "closed state".

[0050] The human presence sensor 54 detects whether or not there is a person within the detection range with respect to the human presence sensor 54. In the present embodiment, the human presence sensor 54 can detect a change from a state where there is a person in the detection range to a state where there is no person in the detection range.

[0051] The human presence sensor 54 is attached to the document table 10. In the present embodiment, the human presence sensor 54 is disposed on the front surface of the document table 10. Further, the human presence sensor 54 generates a detection signal indicating that there is no person in the detection range. The human presence sensor 54 transmits the detection signal to the control unit 70. For example, the human presence sensor 54 is a pyroelectric infrared sensor and detects far-infrared rays (radiant heat) emitted from the human body.

[0052] Next, the reading unit 20 will be described in more detail with reference to FIG. 4. FIG. 4 is an enlarged view of the reading unit 20 shown in FIG. 3. The reading unit 20 includes a scan sensor 21 and a transport system 25. The scan sensor 21 is disposed below the contact glass 11. The scan sensor 21 is an image sensor used for reading a document placed on the contact glass 11. The image sensor includes, for example, a charge coupled device (CCD).

[0053] The scan sensor 21 emits light upward from the internal light source through the contact glass 11. The scan sensor 21 emits light to the document placed on the contact glass 11 while being transported in the left-right direction. For example, the scan sensor 21 irradiates the document placed on the contact glass 11 with light while moving from left to right along the left-right direction. The scan sensor 21 receives the light reflected from the document, converts it into an electrical signal, and outputs it to the image forming unit 110.

[0054] The conveying system 25 is a device that reciprocates the scan sensor 21 based on a control command from the control unit 70 below the contact glass 11. The conveying system 25 conveys the scan sensor 21 from the reading reference position to the end position. The reading reference position is the position where the scan sensor 21 starts reading with respect to the document placed on the contact glass 11. The end position is the position where the scan sensor 21 finishes reading with respect to the document placed on the contact glass 11.

[0055] The conveying system 25 includes a motor 26, a guide member 27, a conveying belt 28, and a transmission mechanism 60. The motor 26 generates power when driven. The motor 26 is an example of a "driving source". The rotation axis Ax1 of the motor 26 extends along the vertical direction. The motor 26 is provided with a motor gear 26A that serves as an output shaft.

[0056] The guide member 27 is connected to the scan sensor 21 and guides the scan sensor 21 in the left - right direction. The guide member 27 includes a rail 27A and a nut 27B. The rail 27A is a member that extends in the left - right direction. The nut 27B is movable in the left - right direction on the rail 27A. The nut 27B is connected to the scan sensor 21.

[0057] The conveying belt 28 is a conveying member that operates with the drive of the motor 26 and conveys the scan sensor 21. The conveying belt 28 is connected to the scan sensor 21 via the nut 27B. The conveying belt 28 extends in the left - right direction. One (right - hand) end of the conveying belt 28 engages with the transmission mechanism 60, and the other (left - hand) end engages with a pulley (not shown). By operating so that the conveying belt 28 circulates between the transmission mechanism 60 and the pulley, the scan sensor 21 moves in the left - right direction.

[0058] Next, the configuration of the transmission mechanism 60 that constitutes the conveyance system 25 will be described in detail. FIG. 5 is a partially enlarged view of the conveyance system 25 shown in FIG. 4. FIG. 6 is a longitudinal sectional view of the transmission mechanism 60. As shown in FIG. 5, the transmission mechanism 60 is a gear unit that transmits the power generated by the drive of the motor 26 to the conveyance belt 28 to operate the conveyance belt 28. As shown in FIG. 6, the transmission mechanism 60 includes a first gear 61, a second gear 62, and a clutch 63.

[0059] The first gear 61 is a gear that rotates by the power generated by the drive of the motor 26. The first gear 61 is a spur gear whose central axis Ax2 extends along the vertical direction. In the following description, the direction along the central axis Ax2 is referred to as the axial direction. Also, the direction orthogonal to the central axis Ax2 is referred to as the radial direction, and the direction of orbiting around the central axis Ax2 is referred to as the circumferential direction.

[0060] A through hole 61A that penetrates the first gear 61 in the axial direction is formed in the central portion in the radial direction of the first gear 61. The through hole 61A is arranged coaxially with the central axis Ax2. A recess 61B that depresses upward in the axial direction is formed on the axial end surface of the first gear 61. The recess 61B is formed on the lower end surface of the first gear 61 and opens downward.

[0061] An accommodation cylinder 61C that opens inward in the radial direction is formed on the inner peripheral surface of the recess 61B of the first gear 61. A pair of accommodation cylinders 61C are arranged on the inner peripheral surface of the recess 61B so as to sandwich the central axis Ax2 in the radial direction.

[0062] In the recess 61B of the first gear 61, a protruding piece 61D that protrudes downward is formed on the bottom surface facing downward. The lower end portion of the protruding piece 61D protrudes outward in the front-rear direction. A pair of protruding pieces 61D are arranged on the bottom surface of the recess 61B so as to sandwich the central axis Ax2 in the radial direction.

[0063] The second gear 62 is a gear that engages with the conveyor belt 28 and rotates by the power transmitted from the first gear 61. The first gear 61 and the second gear 62 are arranged coaxially with each other. The second gear 62 generally presents a hollow cylindrical shape. A shaft 66 is inserted into the hollow portion of the second gear 62.

[0064] The second gear 62 has an engaging portion 62A, a connecting portion 62B, and a held portion 62C. The engaging portion 62A, the connecting portion 62B, and the held portion 62C are arranged coaxially with each other and integrally formed. These configurations will be described in detail below.

[0065] The engaging portion 62A is a cylindrical member that engages with the conveyor belt 28. The engaging portion 62A is arranged at the uppermost position of the second gear 62. As shown in FIG. 5, the engaging portion 62A presents a substantially circular shape when viewed from the axial direction. Teeth that mesh with the ribs on the inner surface of the conveyor belt 28 are formed on the outer peripheral surface of the engaging portion 62A.

[0066] A retaining member 67 and a retaining ring 68 are attached to the upper end portion of the shaft 66, at a portion located above the engaging portion 62A (see FIG. 6). The retaining member 67 is a member that prevents the conveyor belt 28 from coming off the engaging portion 62A. The retaining ring 68 is a member that fixes the retaining member 67 to the shaft 66.

[0067] As shown in FIG. 6, the connecting portion 62B presents a cylindrical shape with an outer diameter larger than that of the engaging portion 62A. The connecting portion 62B is arranged below the engaging portion 62A. The connecting portion 62B is inserted into the through hole 61A of the first gear 61. The fitting between the first gear 61 and the connecting portion 62B is preferably a clearance fit. The connecting portion 62B connects the engaging portion 62A and the held portion 62C.

[0068] The held portion 62C is arranged below the engaging portion 62A. The held portion 62C is arranged within the recess 61B of the first gear 61. That is, at least a part of the second gear 62 is arranged within the recess 61B.

[0069] FIG. 7 is a bottom view of the transmission mechanism 60. As shown in FIG. 7, the held portion 62C has a substantially polygonal shape when viewed in the axial direction. In the illustrated example, the held portion 62C has a hexagonal shape. The connecting portion 62B is held by the clutch 63. In this way, by holding the second gear 62 by the clutch 63 while engaging with the conveyor belt 28, the configuration of the transmission mechanism 60 can be simplified and the number of parts can be reduced.

[0070] As shown in FIG. 6, the clutch 63 is disposed between the inner peripheral surface of the concave portion 61B of the first gear 61 and the second gear 62. Therefore, the axial size of the transmission mechanism 60 can be made compact. A pair of clutches 63 are arranged at positions sandwiching the second gear 62 in the radial direction. The clutch 63 holds the second gear 62 with respect to the first gear 61, and transmits the power of the first gear 61 to the second gear 62 in a cut-off manner.

[0071] The clutch 63 has a slider 64 and a coil spring 65. The slider 64 is a member that contacts the second gear 62. Among the sliders 64, the surface that contacts the held portion 62C of the second gear 62 is flat (see FIG. 7). The slider 64 is an example of the "contact portion". The slider 64 has a hollow rectangular parallelepiped shape and is open toward the outside in the radial direction. The slider 64 is slidable in the radial direction.

[0072] As shown in FIG. 6, a slit 64A is formed in the side surface of the slider 64. Inside the slit 64A, a portion of the lower end of the protruding piece 61D of the first gear 61 that protrudes outward in the front-rear direction is inserted. The slider 64 is guided and displaced in the radial direction as the slit 64A moves along the protruding piece 61D.

[0073] The coil spring 65 is a spring member extending along the radial direction. The outer end of the coil spring 65 in the radial direction is accommodated in the accommodation cylinder 61C of the first gear 61. The inner end of the coil spring 65 in the radial direction is connected to the slider 64. The coil spring 65 biases the contact portion toward the inner side in the radial direction to press the second gear 62. The coil spring 65 is an example of a "biasing portion". That is, the clutch 63 holds the second gear 62 by the biasing force of the coil spring 65 toward the inner side in the radial direction.

[0074] Next, with reference to FIG. 7, the power transmission by the transmission mechanism 60 will be described. FIG. 7A is a diagram showing a state where the transmission mechanism 60 is transmitting power. FIG. 7B is a diagram showing a state where the transmission mechanism 60 has stopped power transmission.

[0075] As shown in FIG. 7A, the clutch 63 holds the second gear 62 with respect to the first gear 61. Specifically, the coil spring 65 accommodated in the accommodation cylinder 61C of the first gear 61 biases the slider 64 toward the inner side in the radial direction, so that the slider 64 presses the outer peripheral surface of the held portion 62C of the second gear 62.

[0076] Thereby, the relative displacement of the second gear 62 in the circumferential direction with respect to the first gear 61 is restricted. In this state, when the motor gear 26A rotates as the motor 26 is driven, the first gear 61 meshing with the motor gear 26A rotates toward one side in the circumferential direction by the power of the motor 26.

[0077] When the first gear 61 rotates, the second gear 62 is held by the clutch 63 and the relative displacement in the circumferential direction with respect to the first gear 61 is restricted, so the second gear 62 rotates with the first gear 61. Thereby, the second gear 62 rotates toward one side in the circumferential direction. That is, since the clutch 63 holds the second gear 62 with respect to the first gear 61, the rotational force of the first gear 61 is transmitted to the second gear 62.

[0078] When the second gear 62 rotates, the conveying belt 28 engaged with the engaging portion 62A (see FIG. 6) of the second gear 62 operates, and the scan sensor 21 connected to the conveying belt 28 is guided by the guide member 27 and displaced in the left - right direction. The amount of displacement of the scan sensor 21 in the left - right direction is defined based on the amount of rotation of the second gear 62.

[0079] The control unit 70 controls the driving amount of the motor 26 according to the size of the document to be read in the left - right direction. In this way, by transmitting power from the first gear 61 to the second gear 62 through the transmission mechanism 60, the scan sensor 21 is conveyed by the conveying system 25.

[0080] Next, a state where the transmission of power by the transmission mechanism 60 is stopped will be described. The control unit 70 may lose sight of the reading reference position or the end position of the scan sensor 21. In this case, if the scan sensor 21 continues to move in the left - right direction beyond the reading reference position or the end position, the scan sensor 21 may come into contact with the inner wall of the image reading apparatus 100 and be unable to move further. If the motor 26 is driven in this state, the transmission mechanism 60 stops transmitting power to the conveying belt 28.

[0081] Specifically, as shown in FIG. 7B, when the scan sensor 21 is in a state where it cannot move and the first gear 61 rotates further, a reaction force is transmitted from the scan sensor 21 in contact with the wall surface to the second gear 62 via the conveying belt 28. At this time, when the reaction force transmitted to the second gear 62 via the conveying belt 28 exceeds the holding force, the clutch 63 cuts off the transmission of power from the first gear 61 to the second gear 62. For this reason, it is possible to suppress the reaction force acting on the conveying belt 28 from becoming too high and suppress the wear of the conveying belt 28.

[0082] That is, when the reaction force transmitted to the second gear 62 exceeds the biasing force of the coil spring 65 on the slider 64, the clutch 63 shuts off the transmission of power from the first gear 61 to the second gear 62. Therefore, by adjusting the biasing force of the coil spring 65, the reaction force when shutting off the transmission of power from the first gear 61 to the second gear 62 can be arbitrarily adjusted.

[0083] Specifically, as shown in FIG. 7B, due to the reaction force transmitted from the conveyor belt 28 to the second gear 62, the slider 64 is pressed radially outward by the held portion 62C of the second gear 62 whose rotation in one circumferential direction has stopped. The slider 64 compresses the coil spring 65 radially outward against the biasing force from the coil spring 65. At this time, the slider 64 is displaced radially outward so as to cover the housing cylinder 61C of the first gear 61.

[0084] Thereby, the slider 64 rides over the corner portion of the held portion 62C of the second gear 62, causing the first gear 61 to be displaced circumferentially relative to the second gear 62. In this way, the clutch 63 stops the transmission of power to the conveyor belt 28 by releasing the power transmitted from the motor 26 to the first gear 61.

[0085] That is, when the load acting on the conveyor belt 28 from the motor 26 via the transmission mechanism 60 exceeds the threshold value, the transmission mechanism 60 stops the transmission of power to the conveyor belt 28. Thereby, the conveyance system 25 can prevent the scan sensor 21 from being pressed against the inner wall of the image reading apparatus 100.

[0086] Thereafter, the control unit 70 notifies the display unit 41 that an error has occurred regarding the position of the scan sensor 21. The user checks this notification and inputs an instruction for calibration to adjust the position of the scan sensor 21 to the input unit 42. Thereby, the control unit 70 recognizes again the reading reference position or the end position of the scan sensor 21. The control unit 70 moves the scan sensor 21 to an appropriate position by the conveyance system 25.

[0087] When the scanning sensor 21 moves to an appropriate position, the slider 64 presses the held portion 62C of the second gear 62 radially inward again. As a result, the holding of the second gear 62 with respect to the first gear 61 by the clutch 63 is restored. Therefore, the transmission of the power of the motor 26 from the first gear 61 to the second gear 62 by the clutch 63 is restarted, and the scanning sensor 21 can resume the reciprocating movement in the left - right direction necessary for the reading process of the document. In this way, when the scanning sensor 21 moves to an appropriate position, the clutch 63 automatically restores the holding state of the second gear 62, so that the labor of the user for error elimination work can be reduced. When the scanning sensor 21 moves to an appropriate position, the slider 64 presses the held portion 62C of the second gear 62 radially inward again. As a result, the holding of the second gear 62 with respect to the first gear 61 by the clutch 63 is restored. Therefore, the transmission of the power of the motor 26 from the first gear 61 to the second gear 62 by the clutch 63 is restarted, and the scanning sensor 21 can resume the reciprocating movement in the left - right direction necessary for the reading process of the document. In this way, when the scanning sensor 21 moves to an appropriate position, the clutch 63 automatically restores the holding state of the second gear 62, so that the labor of the user for error elimination work can be reduced.

[0088] The embodiments of the present invention have been described above with reference to the drawings (FIGS. 1 to 7). However, the present invention is not limited to the above - described embodiments, and can be implemented in various forms without departing from the gist thereof. Also, by appropriately combining a plurality of components disclosed in the above - described embodiments, various inventions can be formed. For example, some components may be deleted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. The drawings are schematically shown mainly for each component for easy understanding, and the thickness, length, number, interval, etc. of each illustrated component may be different from the actual ones for convenience of drawing preparation. Also, the materials, shapes, dimensions, etc. of each component shown in the above - described embodiments are examples and are not particularly limited, and various changes can be made without substantially departing from the effects of the present invention.

[0089] (1) In this embodiment, it is not limited to the image forming apparatus 200 including the image reading apparatus 100. The image forming apparatus 200 may be a copying machine, a printer, a facsimile machine, a scanner, or a multifunction machine having these functions.

[0090] (2) As described with reference to FIG. 1, the image reading apparatus 100 includes the document conveying unit 90. However, the image reading apparatus 100 may not include the document conveying unit 90. In this case, the document table 10 includes the contact glass 11 and the light transmitting portion 12, and does not include the reading slit 13.

[0091] (3) In the present embodiment, the transmission mechanism 60 is shown to have the first gear 61, the second gear 62, and the clutch 63. However, the transmission mechanism 60 is not limited to this configuration. As long as the transmission mechanism 60 has a function of stopping the transmission of power to the conveyance belt 28 when the load acting on the conveyance belt 28 exceeds the threshold value, any configuration can be adopted.

[0092] (4) In the present embodiment, the clutch 63 is shown to have the slider 64 and the coil spring 65. However, the clutch 63 is not limited to this configuration. The clutch 63 may have a member having a configuration different from that of the slider 64 as the contact portion. For example, the contact portion may have a curved surface that contacts the held portion 62C of the second gear 62. In this case, the movement when the contact portion rides over the corner portion of the held portion 62C of the second gear 62 can be made smooth. Further, the clutch 63 may have a member having a configuration different from that of the coil spring 65 as the biasing portion.

[0093] (5) In the present embodiment, the second gear 62 and the clutch 63 are shown to be arranged in the concave portion 61B of the first gear 61. However, the present invention is not limited to this configuration. Without the concave portion 61B being formed on the end surface of the first gear 61, the second gear 62 and the clutch 63 may be arranged side by side with the first gear 61 in the axial direction.

[0094] (6) In the present embodiment, the held portion 62C of the second gear 62 is shown to have a hexagonal shape in plan view. However, the present invention is not limited to this configuration. The held portion 62C may have a polygonal shape other than a hexagon. Further, chamfering with an R surface by rounding may be performed on the corner portions of the held portion 62C. In this case, the movement when the slider 64 rides over the corner portion of the held portion 62C of the second gear 62 can be made smooth.

Industrial Applicability

[0095] The present invention provides an image reading device and an image forming device, and has industrial applicability.

Explanation of Signs

[0096] 11 Contact glass (placement part) 21 Scan sensor 25 Conveying system 26 Motor (driving source) 28 Conveyor belt 60 Transmission mechanism 61 First gear 61B Concave part 62 Second gear 62A Engaging part 62B Connecting part 62C Held part 63 Clutch 64 Slider (contact part) 65 Coil spring (biasing part) 100 Image reading device 200 Image forming device

Claims

1. A placement section on which a manuscript to be read is placed on the upper surface, A scan sensor that is disposed below the placement section and is used for reading an image of the manuscript, A conveyance system that reciprocally moves the scan sensor and includes: The conveyance system includes a drive source that generates power by being driven, a conveyance belt that operates in accordance with the drive of the drive source and conveys the scan sensor, and a transmission mechanism that transmits the power generated by the drive of the drive source to the conveyance belt to operate the conveyance belt. The transmission mechanism is an image reading apparatus that stops the transmission of power to the conveyance belt when the load acting on the conveyance belt from the drive source via the transmission mechanism exceeds a threshold value.

2. The transmission mechanism includes a first gear that rotates by the power generated by the drive of the drive source, a second gear that engages with the conveyance belt and rotates by the power transmitted from the first gear, and a clutch that holds the second gear with respect to the first gear and transmits the power of the first gear to the second gear in a cut-off manner. The clutch is the image reading apparatus according to claim 1, which cuts off the transmission of power from the first gear to the second gear and stops the transmission of power to the conveyance belt when the reaction force transmitted to the second gear via the conveyance belt exceeds the holding force of the clutch.

3. The first gear and the second gear are arranged coaxially with each other. The clutch has a contact portion that contacts the second gear, and a biasing portion that biases the contact portion radially inward to press the second gear. The clutch is the image reading apparatus according to claim 2, which cuts off the transmission of power from the first gear to the second gear when the reaction force transmitted to the second gear via the conveyance belt exceeds the biasing force of the biasing portion on the contact portion.

4. A recess is formed on an axial end surface of the first gear. At least a part of the second gear is disposed within the recess. The clutch is disposed between an inner peripheral surface of the recess and the second gear, and is the image reading apparatus according to claim 3.

5. The second gear has an engagement portion that engages with the conveyance belt and has a substantially circular shape when viewed axially, and a held portion that is disposed coaxially with the engagement portion, has a substantially polygonal shape when viewed axially, and is held by the clutch. The image reading apparatus according to claim 2.

6. An image reading apparatus according to any one of claims 1 to 5, an image forming unit that forms an image corresponding to the image read by the scanning sensor on a recording medium and an image forming apparatus comprising the same.

Images