Image reading apparatus and image forming apparatus

An image reading apparatus having a conveyed document reading function and a placed document reading function includes: a moving mechanism for moving an imaging unit; a hinge mechanism for swingably connecting a document cover to a document platen; a conveyance mechanism provided to the document cover for conveying a document upon operation of the conveyed document reading function; a driving force transmission mechanism for selectively transmitting a driving force generated from a driving source to the moving mechanism or the conveyance mechanism; a first gear rotatable by receiving the driving force from the driving force transmission mechanism; and a second gear rotatable with being meshed with the first gear for transmitting the driving force to the moving mechanism or the conveyance mechanism, a rotating center line of which coincides with a swinging center line of the hinge mechanism.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application No. 2012-259987 filed on Nov. 28, 2012, the entire subject matter of which is incorporated herein by reference.

TECHNICAL FIELD

Illustrative aspects of the invention relate to an image reading apparatus and an image forming apparatus having the image reading apparatus.

BACKGROUND

There have been disclosed an image reading apparatus configured to drive a document conveyance mechanism for implementing a conveyed document reading function and an imaging unit reciprocating mechanism for implementing a placed document reading function by one driving source.

The driving source and the imaging unit reciprocating mechanism are provided to a document platen. The document conveyance mechanism is provided to a document cover. Incidentally, the document cover is rotatably connected to the document platen through a hinge mechanism.

Further, according to the related-art image reading apparatus, a driving force is transmitted from the document platen to the document cover through a joint part having an output part provided to the document platen and an input part provided to the document cover.

The output part is provided at a part of one end-side in a moving direction of the imaging unit, which part deviates from a hinge mechanism towards a placing surface. Incidentally, the placing surface is an area in which a document is to be placed when performing a reading operation by the placed document reading function.

SUMMARY

In the above-described related-art image reading apparatus, the output part and the input part are displaced such that they are separated and contacted from and to each other in conjunction with rotation of the document cover. That is, at a state where the placing surface is covered by the document cover, the output part and the input part are connected, so that the driving force can be transmitted. On the other hand, at a state where the document cover is spaced from the placing surface, the output part and the input part are separated, so that the driving force cannot be transmitted.

Therefore, illustrative aspects of the invention provide a configuration for transmitting a driving force.

According to one illustrative aspect of the invention, there is provided an image reading apparatus having a conveyed document reading function of reading a conveyed document and a placed document reading function of reading a document placed on a placing surface of a document platen, the image reading apparatus comprising: an imaging unit that is movable below the placing surface; a moving mechanism configured to move the imaging unit; a document cover that is displaceable between a position closing the placing surface and a position spaced from the placing surface; a hinge mechanism configured to connect the document cover to the document platen such that the document cover is swingable; a conveyance mechanism that is provided to the document cover and is configured to convey a document placed on the document cover upon operation of the conveyed document reading function; a driving force transmission mechanism configured to selectively transmit a driving force generated from a driving source to the moving mechanism or the conveyance mechanism; a first gear which, when the driving force is transmitted to the moving mechanism or the conveyance mechanism, is configured to rotate by receiving the driving force from the driving force transmission mechanism; and a second gear configured to rotate with being meshed with the first gear and to transmit the driving force to the moving mechanism or the conveyance mechanism, the second gear having a rotating center line coinciding with a swinging center line of the hinge mechanism.

According thereto, it is possible to swing the document cover with the first gear being meshed with the second gear. That is, it is possible to transmit the driving force all the time, irrespective of a position of the document platen5. Therefore, it is possible to transmit the driving force by the configuration different from the above-described related art.

DETAILED DESCRIPTION

An ‘exemplary embodiment of the invention’ that will be described later shows an example of an exemplary embodiment. That is, the invention are not limited to specific means and structure and the like described in the below exemplary embodiment.

Hereinafter, an image forming apparatus and an image reading apparatus according to an exemplary embodiment of the invention will be described with reference to the drawings. Incidentally, arrows and the like indicating directions in the respective drawings are shown so as to easily understand a relation between the drawings, and the invention is not limited to the directions shown in the respective drawings.

1. Outline of Image Forming Apparatus

As shown inFIG. 1, an image forming apparatus100according to an exemplary embodiment integrally includes an image reading apparatus1and an image forming unit50. The image forming unit50is accommodated in a housing53. A joint cover53A is provided at an upper part of the housing53. The joint cover53A connects the image reading apparatus1and the image forming unit50with a space53B therebetween.

The image forming unit50is configured to form an image on a sheet. The sheet having the image formed by the image forming unit50is discharged to the space53B and is then placed onto a discharge tray55that is provided on an upper surface of the housing53. Incidentally, the image forming unit50of this exemplary embodiment is an electrophotographic type of transferring developer to the sheet to thereby form the image.

2. Outline of Image Reading Apparatus

The image reading apparatus1has a conveyed document reading function and a placed document reading function. The conveyed document reading function is a function of reading a document being conveyed. The placed document reading function is a function of reading a document that is placed on a placing surface3A of a document platen3shown inFIG. 2.

The document platen3is provided with a first reading window blocked by a transparent platen3B such as glass, acryl and the like. The platen3B configures the placing surface3A. An upper surface of the document platen3is mounted with a document cover5via a plurality of hinge mechanisms5A,5B.

The respective hinge mechanisms5A,5B are fixed to the document platen3by restraint parts5C. That is, the respective restraint parts5C restrain a swinging center line L2of the hinge mechanisms5A,5B from being displaced relative to the document platen3. Incidentally, the restraint part5C of this exemplary embodiment is a mechanical fastening means such as a screw.

The document cover5can be rotation-displaced between a position closing the document platen3(refer toFIG. 1) and a position spaced from the document platen3(refer toFIG. 2). Incidentally, when a document is read using the placed document reading function, it is necessary for a user to manually open upwards the document cover5and then to place a document on the placing surface3A.

An imaging unit7that is movable along the placing surface3A is provided below the placing surface3A. The imaging unit7is configured to receive light that is illuminated and then reflected on a document and to generate an electric signal based on the received light. Then, the image reading apparatus1is configured to convert an image described on the document, such as letters, into an electric signal through the imaging unit7and thus read an image.

In this exemplary embodiment, a CIS (Contact Image Sensor) is used as the imaging unit7. A longitudinal direction of the CIS (the imaging unit7) is just below the placing surface3A and extends in a direction orthogonal to the moving direction of the imaging unit7.

Further, as shown inFIG. 3, the imaging unit7is mounted to the document platen3so that it can be moved in the longitudinal direction of the placing surface3A. A moving mechanism9moves the imaging unit7between a first position and a second position.

The first position is a position that is set at one end-side of the moving direction of the imaging unit7. The second position is a position that is set at the other end-side of the moving direction. Incidentally, in this exemplary embodiment, the ‘longitudinal direction of the placing surface3A’ coincides with a left-right direction of the image reading apparatus1.

The moving mechanism9includes a pulley9B having a first tooth, a pulley9C having a second tooth and a belt9A having a tooth. The pulley9B having a first tooth and the pulley9C having a second tooth are rotatably fixed to the document platen3. The belt9A having a tooth extends between the pulley9B having a first tooth and the pulley9C having a second tooth. The belt9A having a first tooth is applied with a driving force from the pulley9B having a first tooth and is thus rotated.

The imaging unit7is connected to the belt9A having a tooth. Therefore, the imaging unit7is moved along a rotating direction of the belt9A having a tooth. The pulley9B having a first tooth is provided at one end-side of the moving direction of the imaging unit7. The pulley9C having a second tooth is provided at the other end-side of the moving direction of the imaging unit7.

Upon operation of the conveyed document reading function, the imaging unit7reads an image through a second reading window3C at a state where it is stopped just below the second reading window3C. On the other hand, upon operation of the placed document reading function, the imaging unit7reads an image while it is being moved just below the placing surface3A.

Incidentally, the second reading window3C is also blocked by a transparent platen such as glass, like the first reading window, e.g., the placing surface3A. The placing surface3A and the second reading window3C are partitioned by a beam-shaped partition member3D.

Further, an adjustment basis3E is provided at a part that is a boundary part between the placing surface3A and the second reading window3C and faces the imaging unit7, as shown inFIG. 5. The adjustment basis3E is to re-adjust a basis of a color and shading and a basis position of the imaging unit7upon reading.

That is, the adjustment basis3E includes a white background part3F that extends in the extending direction (a front-rear direction, in this exemplary embodiment) of the imaging unit7and black background parts3G that are provided at both ends in the extending direction of the white background part3F. A control unit30that will be described later is configured to execute the reading with using read data obtained when reading of the white background part3F as a basis of the color and shading.

Further, the control unit30determines a standby position (which is also referred to as a home position) of the imaging unit7on the basis of a boundary position of the white background part3F and the black background parts3G and controls the moving mechanism9, e.g., controls a rotation of a driving source31that will be described later.

Incidentally, the standby position is set at the second position-side, rather than the first position. The adjustment basis3E is set at the second position-side, rather than the standby position. That is, regarding the moving direction of the imaging unit7, the first position, the standby position, the adjustment basis3E and the second position are arranged in order of the first position, the standby position, the adjustment basis3E and the second position from one end-side of the moving direction.

Further, as shown inFIG. 4, the document cover5is provided with a conveyance mechanism11. The conveyance mechanism11is an example of the auto document feeder that conveys a document towards the second reading window3C upon operation of the conveyed document reading function.

That is, the conveyance mechanism11sequentially conveys one or more documents one at a time, which are placed on a document tray11A, towards the second reading window3C and sequentially discharges the documents, for which the reading has been completed, towards a discharge tray11B.

The conveyance mechanism11includes a suction roller11C, a separation roller11D, a separation pad11E, a conveying roller11F and the like. The suction roller11C delivers the document placed on the document tray11A towards the separation roller11D.

The separation roller11D is configured to separate two or more overlapping sheets one sheet by one sheet in cooperation with the separation pad11E and deliver the sheet to the conveying roller11F. The conveying roller11F is configured to convey the document to the second reading window3C.

3. Driving Force Transmission Mechanism

3.1 Configuration of Driving Force Transmission Mechanism

In this exemplary embodiment, the moving mechanism9and the conveyance mechanism11are driven by one driving source31. That is, the driving force transmission mechanism13is configured to selectively transmit a driving force, which is generated in the driving source31such as an electric motor, to the moving mechanism9or the conveyance mechanism11. Incidentally, the driving source31and the driving force transmission mechanism13are arranged at positions lower than the placing surface3A in the document platen3.

In this exemplary embodiment, as shown inFIG. 6, the driving force transmission mechanism13is configured by a planetary gear mechanism having a sun gear15, a planetary gear17, a meshing part19and the like. The sun gear15is rotated without being displaced relative to the document platen3.

The sun gear15is rotated by a driving force applied from the driving source31and a rotating direction thereof is a forward rotation or reverse rotation in conjunction with a rotating direction of the driving source31. Incidentally, the driving source31is provided in a space opposite to a space of the placing surface3A with the sun gear15being interposed therebetween, e.g., a space below the sun gear15in this exemplary embodiment.

The planetary gear17is rotated with being meshed with the sun gear15and has a rotation center O1capable of revolving around the sun gear15between a third position shown inFIG. 6and a fourth position shown inFIG. 9about a rotation center of the sun gear15serving as a revolution center. Incidentally, an operation that the planetary gear17is rotated about the rotation center O1is hereinafter referred to as rotation.

When the sun gear15is rotated, the planetary gear17is applied with a force (hereinafter, referred to as a rotation force) enabling the planetary gear17to rotate on its own axis and a force (hereinafter, referred to as a revolution force) enabling the planetary gear17to revolve around the sun gear15. Therefore, when the sun gear15is rotated in the forward direction, a revolution force in a direction (a right rotating direction inFIG. 6) from the fourth position towards the third position is applied to the planetary gear17.

On the other hand, when the sun gear15is rotated in the reverse direction, a revolution force in a direction (a left rotating direction inFIG. 6) from the third position towards the fourth position is applied to the planetary gear17. When the revolution force becomes larger, the planetary gear17revolves around the sun gear15in the direction of the revolution force. On the other hand, when the revolution force is small, the planetary gear17rotates on its own axis without revolving around the sun gear15.

Incidentally, a direction along which the planetary gear17rotates on its own axis when the sun gear15is rotated in the forward direction is referred to as a forward rotation direction of the planetary gear17. Likewise, a direction along which the planetary gear17rotates on its own axis when the sun gear15is rotated in the reverse direction is referred to as a reverse rotation direction of the planetary gear17.

An arm17A supports the planetary gear17so that it can rotate on its own axis and revolve around the sun gear15. One end of the arm17A in an extending direction thereof is rotatably supported on the same axis as the sun gear15. The planetary gear17is rotatably mounted to the other end of the arm17A in the extending direction thereof.

Further, the document platen3is provided with a second stopper part3H and a third stopper part3J for restraining rotation of the arm17A. The arm17A is provided with a second contacted part17B configured to contact the second stopper part3H and a third contacted part17C configured to contact the third stopper part3J.

As shown inFIG. 6, the second stopper part3H is contacted to the second contacted part17B at the third position to thus restrain the arm17A from being rotated rightwards on the sheet. As shown inFIG. 9, the third stopper part3J is contacted to the third contacted part17C at the fourth position to thus restrain the arm17A from being rotated leftwards on the sheet.

Further, a first spring17D restrains the planetary gear17from being spaced from a first output gear21when the sun gear15is rotated in the reverse direction. That is, the first spring17D is configured to apply a force (hereinafter, referred to as a first restraint force), which restrains the planetary gear17from revolving around the sun gear15towards the fourth position at least when the planetary gear17is located at the third position, to the planetary gear17.

Incidentally, in this exemplary embodiment, the first spring17D is a tension coil spring. One end of the first spring17D in an extension direction thereof is connected to an opposite side of the planetary gear17with a rotating center of the arm17A being interposed therebetween and the other end thereof in the extension direction is connected to the document platen3.

Therefore, the first spring17D applies a force (hereinafter, referred to as a second restraint force), which restrains the planetary gear17from revolving around the sun gear15towards the third position when the planetary gear17is located at the fourth position, to the arm17A.

When the planetary gear17is located at the fourth position, it means that the driving force is transmitted to the conveyance mechanism11, at which the sun gear15is rotated in the reverse direction, as described later.

When the sun gear15is rotated in the reverse direction, a force that enables the planetary gear17to revolve around the sun gear15from the third position to the fourth position is applied to the planetary gear17. Therefore, in this exemplary embodiment, at least while the driving force is transmitted to the conveyance mechanism11, e.g., while the sun gear15is meshed with a second output gear23and is rotated in the reverse direction, the planetary gear17keeps staying at the fourth position even though the second restraint force is not applied, for example.

Thus, in this exemplary embodiment, torque with which the first spring17D restrains the revolution of the planetary gear17at the third position is set to be greater than torque with which the first spring17D restrains the revolution of the planetary gear17at the fourth position.

Specifically, positions of one end and the other end of the first spring17D in the extension direction are set so that a deformation amount of the first spring17D at the third position is greater than a deformation amount of the fist spring17D at the fourth position.

The meshing part19is a part that is meshed with teeth of the planetary gear17when the planetary gear17revolves around the sun gear15between the third position and the fourth position. In this exemplary embodiment, the meshing part19is configured by an internally-toothed gear. Thus, the meshing part19is hereinafter referred to as the internally-toothed gear19.

As shown inFIG. 6, the internally-toothed gear19has a plurality of protrusions19A protruding towards the sun gear15. The protrusions19A are an example of a gear that is provided along a revolution path Lo of the planetary gear17.

The internally-toothed gear19is mounted to the document platen3so as to be movable relative to the sun gear15. Incidentally, in this exemplary embodiment, the internally-toothed gear19can be displaced along the revolution path Lo of the planetary gear17about the sun gear15. The internally-toothed gear19is provided with a second spring19B which, when the internally-toothed gear19is moved, is configured to return the internally-toothed gear19to a position before the moving.

The driving force transmission mechanism13includes a first output gear21and a second output gear23, which are meshed with the planetary gear17. As shown inFIG. 3, the second output gear23is provided at a position closer to the hinge mechanism5A than the first output gear21in a direction (a front-rear direction, in this exemplary embodiment) orthogonal to the moving direction of the imaging unit7of directions parallel with the placing surface3A.

That is, the first output gear21is provided at an opposite side to the second output gear23with the sun gear15being interposed therebetween. In other words, the first output gear21is located across the sun gear15from the second output gear23. The rotary shaft directions of the sun gear15, the planetary gear17, the first output gear21and the second output gear23are orthogonal to the placing surface3A.

Further, as shown inFIG. 6, the first output gear21is meshed with the planetary gear17when the planetary gear17is located at the third position. Thus, at the third position, the driving force is transmitted in order of the sun gear15, the planetary gear17and the first output gear21. The pulley9B having a first tooth is driven to operate the moving mechanism9by the first output gear21.

When the sun gear15is rotated in the forward direction, the moving mechanism9moves the imaging unit7from the first position towards the second position. When the sun gear15is rotated in the reverse direction, the moving mechanism9moves the imaging unit7from the second position towards the first position. That is, the imaging unit7is moved in correspondence to the rotating direction of the sun gear15.

As shown inFIG. 9, the second output gear23is meshed with the planetary gear17when the planetary gear17is located at the fourth position. Thus, at the fourth position, the driving force is transmitted in order of the sun gear15, the planetary gear17and the second output gear23, so that the conveying mechanism11is operated.

Also, as shown inFIG. 2, a load generation part25configured to increase a rotational resistance of the first output gear21is provided. The load generation part25increases the rotational resistance of the first output gear21when the imaging unit7is located at the first position, compared to a case where the imaging unit7is located at a position, other than the first position.

That is, in this exemplary embodiment, the load generation part25includes a first contacted part25A, which is provided to the imaging unit7, and a first stopper part25B that is provided to the document platen3. As shown inFIG. 9, the first contacted part25A and the first stopper part25B are contacted to each other.

Therefore, while the sun gear15is rotated in the reverse direction, when the imaging unit7is located at the first position and the first contacted part25A and the first stopper part25B are thus contacted, the imaging unit7is restrained from moving, so that the rotational resistance of the first output gear21is increased.

3.2 Tooth Surface Shapes of Internally-Toothed Gear, Planetary Gear, First Output Gear and Second Output Gear

Toothed curves of gears to be meshed with each other have typically the same toothed curve. Therefore, the gears that are used for the driving force transmission mechanism13have also the same toothed curve, except for a case that will be described later.

Incidentally, all teeth (protrusions) of the sun gear15adopt toothed curves by involute curves. Thus, teeth (protrusions), which are not particularly described, of the teeth (protrusions) of the gears configuring the driving force transmission mechanism13adopt toothed curves by involute curves.

3.2.1 Tooth Surface Shape of Internally-Toothed Gear

Among a plurality of protrusions19A configuring the internally-toothed gear19, tooth surfaces of a first protrusion19C, which is positioned at least at the first output gear21-side, are provided with first collision surfaces19E consisting of a curved or planar surface having a curvature radius larger than the toothed curve of the sun gear15, as shown inFIG. 10.

Further, among the plurality of protrusions19A configuring the internally-toothed gear19, tooth surfaces of a second protrusion19D, which is positioned at least at the second output gear23-side, are provided with second collision surfaces19F consisting of a curved or planar surface having a curvature radius larger than the toothed curve of the sun gear15, as shown inFIG. 11.

Incidentally, in this exemplary embodiment, the first protrusion19C and the second protrusion19D have the same shape, and the other protrusions19A except for the first protrusion19C and the second protrusion19D have the toothed curve by the involute curve. That is, the other protrusions19A have the toothed curve that is formed in accordance with the same theory as the sun gear15.

When the planetary gear17revolves around the sun gear15from the fourth position towards the third position, e.g., when the planetary gear17is rotated in the reverse direction, a backward tooth surface of the tooth surfaces of the planetary gear17in the rotation direction is provided with a third collision surface17F consisting of a curved or planar surface having a curvature radius larger than the toothed curve of the sun gear15.

Incidentally, the ‘backward tooth surface of the tooth surfaces of the planetary gear17in the rotation direction’ means a left tooth surface inFIG. 10. Further, an opposite surface to the third collision surface17F, e.g., a forward tooth surface of the tooth surfaces of the planetary gear17in the rotation direction has the same shape as the tooth surface of the sun gear15.

3.2.3 Tooth Surface Shape of First Output Gear (Refer toFIG. 10)

When the sun gear15is rotated in the direction along which the planetary gear17revolves around the sun gear15from the four position to the third position, e.g., when the planetary gear17and the first output gear21are rotated in the reverse direction, a forward tooth surface of the tooth surfaces of the first output gear21in the rotating direction is provided with a fourth collision surface21A consisting of a curved or planar surface having a curvature radius larger than the toothed curve of the sun gear15.

Incidentally, the ‘forward tooth surface of the tooth surfaces of the first output gear21in the rotating direction (reverse rotating direction)’ means a right tooth surface inFIG. 10.

3.2.4 Tooth Surface Shape of Second Output Gear (Refer toFIG. 11)

A forward tooth surface of the tooth surfaces of the second output gear23in the rotating direction is provided with a fifth collision surface23A consisting of a curved or planar surface having a curvature radius larger than the toothed curve of the sun gear15.

Incidentally, at the fourth position, e.g., when the driving force is transmitted to the second output gear23, the planetary gear17is rotated in the reverse direction. Therefore, the ‘rotating direction of the second output gear23’ means a rotating direction when the planetary gear17is rotated in the reverse direction. The ‘forward tooth surface of the tooth surfaces of the second output gear23in the rotating direction’ is a right tooth surface inFIG. 11.

Further, in this exemplary embodiment, all of the first collision surface19E, the second collision surface19F, the third collision surface17F, the fourth collision surface21A and the fifth collision surface23A have a planar surface shape and have the same shape.

4. Transmission of Driving Force from Driving Force Transmission Mechanism to Conveyance Mechanism

As shown inFIG. 12, the driving force transmitted to the second output gear23by the driving force transmission mechanism13is transmitted to the conveyance mechanism11at least through a first gear41and a second gear42.

That is, when the driving force is transmitted to the conveyance mechanism11, the first gear41is applied with the driving force from the driving force transmission mechanism13through the second output gear23and is thus rotated. The second gear42is rotated with being meshed with the first gear41and transmits the driving force to the conveyance mechanism11.

A rotating center line L1of the second gear42coincides with the swinging center line L2of at least the hinge mechanism5A. That is, the extension line of the rotating center line L1overlaps with the swinging center line L2. Incidentally, in this exemplary embodiment, as shown inFIG. 2, the pair of hinge mechanisms5A,5B has the swinging center lines that coincide with each other. Therefore, the rotating center line L1of the second gear42coincides with the swinging center line L2of any hinge mechanisms5A,5B.

Further, as shown inFIG. 12, the first gear41and the second gear42are conical bevel gears. Hence, the rotating direction of the driving force transmitted to the first gear41is changed by 90° by the second gear42.

That is, the swinging center line L2of the hinge mechanism5A and the rotating center line L1of the second gear42are parallel with the placing surface3A. A rotating center line L3of the first gear41is parallel with a direction orthogonal to the placing surface3A. In this exemplary embodiment, since the placing surface3A is substantially horizontal, the rotating center line L3of the first gear41is parallel with a vertical direction.

That is, the driving force transmitted to the first gear41having a vertical direction as the rotating center is converted into a driving force having a horizontal direction as a rotating center by the second gear42. Then, as shown inFIG. 13, a direction of the driving force transmitted to the second gear42is changed into a direction L4that is orthogonal to the rotating center line L1by a third gear43.

The third gear43is a bevel gear configured to transmit the driving force transmitted to the second gear42towards the conveyance mechanism11and is a gear having a rotating center line L4orthogonal to the rotating center line L1of the second gear42. Incidentally, at a state where the document cover5is closed, e.g., at a state shown inFIG. 15, the rotating center line L4of the third gear43is parallel with the placing surface3A, e.g., a shaft line of the conveying roller11A.

Incidentally, in this exemplary embodiment, as shown inFIG. 13, the third gear43is not directly meshed with the second gear42and is indirectly meshed with the second gear42. Specifically, a backside of the second gear42is provided with a bevel gear42A that is integrally rotated with the second gear42about the rotating center line L1serving as the rotating center line. The third gear43is meshed with the bevel gear42A and is thus applied with the driving force from the second gear42.

Incidentally, as shown inFIG. 12, the driving force whose rotating direction has been changed by the third gear43is transmitted to a plurality of gears11G to11J arranged in a direction parallel with the rotating center line L1of the second gear42. The gears11G to11J are gears transmitting the driving force to the respective rollers11C to11F configuring the conveyance mechanism11.

Further, the gears11G to11J are gears having rotating centers parallel with the rotating center line L4of the third gear43. The first gear41is arranged at a part corresponding to a range A, in which the gears11G to11J are provided, in the direction parallel with the rotating center line L1of the second gear42.

Further, the first gear41and the second gear42are provided at a position closer to an end-side of the document platen3than the hinge mechanism5A in the direction parallel with the swinging center line L2, e.g., in an area of the second reading window3C-side relative to the hinge mechanism5A.

Further, at least at the state where the document platen5is closed, the third gear43is positioned at a part that will be described later. That is, regarding the direction parallel with the placing surface3A and orthogonal to the rotating center line L1, the third gear43is provided at a position closer to the placing surface3A than the rotating center line L1of the second gear42, e.g., at the front of the rotating center line L1in the image reading apparatus1.

Further, the swinging center line L2of the hinge mechanism5A and the rotating center line L1of the second gear42are deviated towards the document cover5from the placing surface3A. That is, in this exemplary embodiment, the swinging center line L2of the hinge mechanism5A and the rotating center line L1of the second gear42are higher than the placing surface3A.

As shown inFIG. 14, the driving force is transmitted to the first gear41from an output part13A of the driving force transmission mechanism13through a joint part45. The second output gear23is coupled to the output part13A. The joint part45is configured by a universal joint capable of absorbing the deviation of the rotating center line L5of the output part13A relative to the rotating center line L3of the first gear41. The joint part45will be specifically described later.

5. Mounting Structure of First Gear and Second Gear

As shown inFIG. 13, the first gear41is rotatably supported by a first support part47. The first support part47has at least a thrust bearing surface47A, first radial bearing surfaces47B and a second radial bearing surface47D.

The thrust bearing surface47A is slidingly contacted to a bearing surface41A provided to a larger diameter-side of the first gear41. Thus, the thrust bearing surface47A is applied with load of a direction parallel with the rotating center line L3, which load is a part of loads applied to the first gear41, and restrains the first gear41from being moved in the corresponding direction.

The first radial bearing surfaces47B are slidingly contacted to a circumferential surface41B provided to a backside of the first gear41. The first radial bearing surfaces47B are provided at both sides in a direction orthogonal to the rotating center line L3with the circumferential surface41B being interposed therebetween. The second radial bearing surface47D is slidingly contacted to a circumferential surface41E provided on the tooth surface-side of the first gear41. That is, the second radial bearing surface47D is a sliding contact surface having a semi-circumference shape following the circumferential surface41E.

Therefore, the first radial bearing surfaces47B and the second radial bearing surface47D are applied with load of a direction orthogonal to the rotating center line L3, which load is a part of loads applied to the first gear41, and restrains the first gear41from being moved in the corresponding direction. Incidentally, in this exemplary embodiment, the ‘direction orthogonal to the rotating center line L3’ coincides with a direction parallel with the rotating center line L1.

The second gear42is supported by a second support part49. In this exemplary embodiment, the second support part49is a shaft that coincides with the rotating center line L1of the second gear42and is mounted to the document cover5. Incidentally, the second support part49is a metallic rod penetrating the second gear42, for example.

Further, the second support part49is mounted to the document cover5. Incidentally, the second support part49is mounted to the document cover5so as not to be movable relative to the document cover5by a planar part49A provided to one end-side thereof in a shaft line direction. Thus, the second gear42is rotated with sliding contacting an outer periphery of the second support part49.

On the other hand, the first support part47is mounted to the second support part49. Specifically, as shown inFIG. 15, the first support part47is mounted to the shaft configuring the second support part49with being suspended therefrom. That is, an upper part of the first support part47is provided with holding parts47C sandwiching the second support part49in the upper-lower direction.

The holding parts47C, the thrust bearing surface47A and the first radial bearing surfaces47B are integrated with the first support part47. Hence, an assembly operator can attach and detach the first support part47to and from the second support part49with the first gear41being supported to the first support part47.

Incidentally, the holding parts47C, the thrust bearing surface47A and the first radial bearing surfaces47B are integrally formed with the first support part47by a resin such as POM and the like. Further, the third gear43is mounted to the document cover5through a third support part (not shown). Incidentally, the third support part is a member having two types of bearing surfaces, which is the same as the first support part47.

6. Joint Part

In this exemplary embodiment, the joint part45is a universal joint of a constant joint type, as shown inFIGS. 16A to 16D.

That is, as shown inFIG. 16A, the backside of the first gear41is integrally formed with a cylindrical part41C having the circumferential surface41B on the outer periphery thereof. As shown inFIG. 16D, an inner periphery of the cylindrical part41C is formed with at least two recess portions41D extending in a direction parallel with the rotating center line L3of the first gear41.

As shown inFIG. 16B, the two recess portions41D are formed so that they are deviated from each other by 180°, for example, in a circumferential direction. A first part45A of the joint part45is inserted in the cylindrical part41C. An outer periphery of the first part45A is provided with first protrusions45B that protrude to an inner periphery of the cylindrical part41C and are slidably fitted in the respective recess portions41D.

As shown inFIG. 16D, a cylindrical part45C that is integrally rotated with the first part45A is provided at the second output gear23-side, rather than the first part45A. An inner periphery of the cylindrical part45C is provided with at least two recess portions45D that extend in a direction parallel with the rotating center line L5of the output part13A.

As shown inFIG. 16C, the two recess portions45D are formed so that they are deviated from each other by 180°, for example, in a circumferential direction. A second part45E of the joint part45is inserted in the cylindrical part45C. An outer periphery of the second part45E is provided with first protrusions45F that protrude to an inner periphery of the cylindrical part45C and are slidably fitted in the respective recess portions45D.

Therefore, the first protrusions45B are engaged with the recess portions45D while being displaced in a longitudinal direction of the recess portions41D. Likewise, the second protrusions45F are engaged with the recess portions45D while being displaced in a longitudinal direction of the recess portions45D. Hence, the joint part45transmits the driving force from the output part13A to the first gear41while absorbing the deviation of the rotating center line L5of the output part13A relative to the rotating center line L3of the first gear41.

The driving source31is configured to supply the driving force to the driving force transmission mechanism13, e.g., to the sun gear15. The forward rotation, the reverse rotation and the stopping of the driving source31are controlled by the control unit30. The control unit30is configured by a microcomputer having a CPU, a ROM, a RAM and the like.

A program for controlling operations of the driving unit31, a necessary integer and the like are stored in a non-volatile storage unit such as ROM. The CPU reads out the program from the non-volatile storage unit, thereby enabling the control unit30to function.

A document sensor33is configured to output a signal, which indicates whether a document is placed on the document tray11A, to the control unit30. A reading start switch35is an operation unit that is operated by a user, and is configured to output a starting signal to the control unit30when it is operated by the user. A rotating angle detection unit37is configured to detect a rotating angle of the driving source31and outputs the detected rotating angle to the control unit30.

When the reading start switch35is operated at a state where a document is placed on the document tray11A, the control unit30executes a reading operation by the conveyed document reading function. On the other hand, when the reading start switch35is operated at a state where a document is not placed on the document tray11A, the control unit30executes a reading operation by the placed document reading function.

8. Operations of Driving Force Transmission Mechanism

8.1 When Placed Document Reading Function Operates (Refer toFIG. 6)

When the image reading apparatus1is not operated, the imaging unit7is located at the standby position and the planetary gear17is located at the third position. When the reading start switch35is operated by a user and a reading operation is thus activated by the placed document reading function, the control unit30rotates the driving source31in the forward direction, thereby rotating the sun gear15in the forward direction.

Thereby, the imaging unit7is moved from the standby position towards the second position, e.g., from the first position towards the second position. At this time, the planetary gear17is applied with a revolution force in a direction from the fourth position towards the third position. However, since the second stopper part3H and the second contacted part17B are contacted to each other, the planetary gear17stays at the third position and rotates on its own axis in the forward direction without revolving around the sun gear15.

When a detected angle of the rotating angle detection unit37reaches a predetermined angle, the control unit30rotates the driving source31in the reverse direction, thereby rotating the sun gear15in the reverse direction. Further, when it is determined that the imaging unit7reaches the standby position, the control unit30stops the driving source31. Thereby, the imaging unit7is moved from the second position to the standby position.

When the sun gear15is rotated in the reverse direction, the planetary gear17is applied with a revolution force in a direction from the third position towards the fourth position, e.g., a revolution force in a direction of separating the planetary gear17from the first output gear21. However, the revolution force is cancelled by the first spring17D, so that the planetary gear17stays at the third position and rotates on its own axis in the reverse direction without revolving around the sun gear15.

8.2 When Conveyed Document Reading Function Operates (Refer toFIGS. 7 to 9)

When the image reading apparatus1is not operated, the imaging unit7is located at the standby position and the planetary gear17is located at the third position. When the reading start switch35is operated by a user and a reading operation is thus activated by the conveyed document reading function, the control unit30rotates the driving source31in the reverse direction, thereby rotating the sun gear15in the reverse direction.

Thereby, as shown inFIG. 7, the imaging unit7is moved from the standby position towards the first position. When the imaging unit7is located at the first position and the first stopper part25B and the first contacted part25A are thus contacted to each other, the moving of the imaging unit7is restrained, so that the rotational resistance of the first output gear21is increased.

Therefore, the rotation of the planetary gear17is interrupted and the rotation force is decreased. On the other hand, the revolution force enabling the planetary gear17to revolve around the sun gear15from the third position towards the fourth position is increased. When the revolution force is beyond the first restraint force of the first spring17D, the planetary gear17and the internally-toothed gear19are meshed, so that the planetary gear17starts to revolve around the sun gear15towards the fourth position, as shown inFIG. 8.

When the planetary gear17revolves around the sun gear15and the third stopper part3J and the third contacted part17C are thus contacted to each other, the revolution of the planetary gear17is stopped and the planetary gear17is meshed with the second output gear23, as shown inFIG. 9. Therefore, the driving force is transmitted to the conveyance mechanism11and the document starts to be conveyed.

Further, when it is determined that the reading operation by the conveyed document reading function is completed, the control unit30rotates the driving source31in the forward direction, thereby rotating the sun gear15in the forward direction. Thereby, the planetary gear17is applied with a revolution force in a direction from the fourth position towards the third position.

When the revolution force exceeds the second restraint force of the first spring17D, the planetary gear17revolves around the sun gear15towards the third position, as shown inFIG. 6. When the planetary gear17is located at the third position, the planetary gear17is meshed with the first output gear21, so that the imaging unit7is moved from the first position towards the basis position. Thus, the control unit30stops the driving source31when the imaging unit7reaches the basis position.

9. Features of Image Reading Apparatus in this Exemplary Embodiment

9.1 Driving Force Transmission Mechanism

In this exemplary embodiment, as described above, the planetary gear mechanism having the sun gear15, the planetary gear17, the meshing part19and the like is provided and the rotating direction of the sun gear15is switched to switch the transmission of the driving force.

When the planetary gear17revolves around the sun gear15with being spaced from the first output gear21and the second output gear23, the load interrupting the rotation of the planetary gear17becomes small and the rotation force exceeds the revolution force, so that the revolution may be stopped.

However, in this exemplary embodiment, the arm17A and the side of the planetary gear17are slidingly contacted to each other. Thus, when the planetary gear17rotates on its own axis, a frictional force suppressing the rotation is generated. Therefore, when the planetary gear17revolves around the sun gear15with being spaced from the first output gear21and the second output gear23, the revolution of the planetary gear17is not stopped.

When the sun gear15is rotated in the reverse direction at a state where the planetary gear17is meshed with the first output gear21, torque of the revolution force applied to the planetary gear17is opposite to torque by the first restraint force of the first spring17D.

Therefore, when the first restraint force is small, the planetary gear17revolves around the sun gear15and is thus spaced from the first output gear21, so that it is not possible to move the imaging unit7from the second position towards the first position. On the other hand, when the first restraint force is large, the rotation force of the planetary gear17is increased and a tooth jump phenomenon may occur between the belt9A having a tooth and the pulley9B having a first tooth.

Thus, in this exemplary embodiment, torque with which the first spring17D restrains the revolution of the planetary gear17at the third position is set to be greater than rotational resistance torque of the first output gear21and to be smaller than driving torque of the first output gear21when a tooth jump phenomenon occurs between the belt9A having a tooth and the pulley9B having a first tooth.

Further, in this exemplary embodiment, the internally-toothed gear19can move relative to the sun gear15. Thereby, when the planetary gear17is spaced from the first output gear21or second output gear23and is meshed with the internally-toothed gear19, it is possible to enable the planetary gear17and the internally-toothed gear19to be smoothly meshed with each other.

That is, the protrusions configuring the teeth of the planetary gear17and the protrusions19A configuring the internally-toothed gear19may collide with each other, depending on timing at which the planetary gear17is spaced from the first output gear21or second output gear23, so that the planetary gear17and the internally-toothed gear19may not be meshed with each other.

However, in this exemplary embodiment, when the protrusions configuring the teeth of the planetary gear17and the protrusions19A configuring the internally-toothed gear19collide with each other, the internally-toothed gear19is moved. Therefore, the planetary gear17and the internally-toothed gear19are smoothly meshed with each other.

Further, in this exemplary embodiment, the protrusions19A are provided with the first collision surfaces19E and the second collision surfaces19F.

Thereby, in this exemplary embodiment, when the planetary gear17and the internally-toothed gear19are meshed with each other, the protrusions configuring the teeth of the planetary gear17collide with the first collision surfaces19E or second collision surfaces19F.

Therefore, since the protrusions of the planetary gear17easily slide relative to the first collision surfaces19E or second collision surfaces19F, it is possible to enable the planetary gear17and the internally-toothed gear19to be smoothly meshed with each other when the planetary gear17revolves around the sun gear15.

Further, in this exemplary embodiment, the planetary gear17is provided with the third collision surfaces17F. Thereby, the protrusions of the planetary gear17or protrusions configuring the first output gear21easily slide relative to the other protrusions. Therefore, it is possible to enable the planetary gear17and the first output gear21to be smoothly meshed with each other when the planetary gear17revolves around the sun gear15.

Further, in this exemplary embodiment, the first output gear21is provided with the fourth collision surfaces21A. Thereby, in this exemplary embodiment, the protrusions of the planetary gear17or protrusions configuring the first output gear21easily slide relative to the other protrusions. Therefore, it is possible to enable the planetary gear17and the first output gear21to be smoothly meshed with each other when the planetary gear17revolves around the sun gear15.

Further, when the planetary gear17and the first output gear21are meshed by tooth surfaces having no collision surface (hereinafter, which is referred to as a normal meshed state), a pulsation that is generated in the driving force to be transmitted from the planetary gear17to the first output gear21is decreased.

Therefore, when the planetary gear17and the first output gear21are configured to be at the normal meshed state upon reading of an image, like this exemplary embodiment, it is possible to suppress a quality of a read image from being deteriorated.

Further, in this exemplary embodiment, the second output gear23is provided with the fifth collision surfaces23A. Thereby, in this exemplary embodiment, the protrusions of the planetary gear17or protrusions configuring the second output gear23easily slide relative to the other protrusions. Therefore, it is possible to enable the planetary gear17and the second output gear23to be smoothly meshed with each other when the planetary gear17revolves around the sun gear15.

9.2 Transmission of Driving Force from Driving Force Transmission Mechanism to Conveyance Mechanism

In this exemplary embodiment, the rotating center line L1of the second gear42coincides with the swinging center line L2of the hinge mechanism5A.

Thereby, it is possible to swing the document cover5at a state where the first gear41and the second gear are meshed with each other. That is, in this exemplary embodiment, it is possible to transmit the driving force all the time, irrespective of the position of the document cover5.

That is, since the shaft configuring the second support part49coincides with the swinging center line L2, the second gear42keeps meshing with the first gear41, even though the document cover5swings about the swinging center line L2serving as the swinging center, as shown inFIG. 13.

On the other hand, the third gear43is mounted to the document cover5. Therefore, when the document cover5swings, the third gear43swings about the rotating center line L1serving as the swinging center with being meshed with the bevel gear42A at a state where the rotating center line L3is orthogonal to the rotating center line L1.

Incidentally, a dashed-two dotted line inFIG. 13indicates a position of the third gear43when the document cover5is opened. A solid line indicates a position of the third gear43when the document cover5is closed. The positions of the first gear41and the second gear42are not changed, irrespective of the position of the document cover5.

Further, in this exemplary embodiment, the first gear41and the second gear42are the conical bevel gears. Thereby, in this exemplary embodiment, it is possible to effectively transmit the driving force without enlarging the gear mechanism.

Further, in this exemplary embodiment, the swinging center line L2of the hinge mechanism5A and the rotating center line L1of the second gear42are parallel with the placing surface3A. The rotating center line L3of the first gear41is parallel with the direction orthogonal to the placing surface3A. Further, the third gear43that is a bevel gear transmitting the driving force transmitted to the second gear42towards the conveyance mechanism11and has the rotating center line L4orthogonal to the rotating center line L1of the second gear42is provided. That is, in this exemplary embodiment, the direction of the driving force is changed twice by at least three types of the bevel gears.

Further, in this exemplary embodiment, the joint part45is provided which transmits the driving force from the output part13A of the driving force transmission mechanism13to the first gear41and can absorb the deviation of the rotating center line L5of the output part13A relative to the rotating center line L3of the first gear41. Thereby, even when the position of the document cover5relative to the document platen3is deviated, the deviation can be absorbed by the joint part45.

Further, in this exemplary embodiment, the second support part49is mounted to the document platen3and the first support part47is mounted to the second support part49. Thereby, the first gear41and the second gear42are mounted on the basis of the same member.

Therefore, it is possible to easily improve positional precision of the second gear42relative to the first gear41. Further, since it is possible to enable the first gear41and the second gear42to be favorably meshed with each other, it is possible to effectively transmit the driving force.

Further, in this exemplary embodiment, the third gear43is located at the placing surface3A-side, rather than the rotating center line L1of the second gear42, at least when the document cover5is closed.

If the third gear43is located at an opposite side to the placing surface3A, rather than the rotating center line L1of the second gear42, it is necessary to separately provide a transmission mechanism that guides the driving force transmitted to the third gear43to the placing surface3A-side, rather than the rotating center line L1of the second gear42. However, in this exemplary embodiment, since the transmission mechanism is not required, it is possible to suppress an external size of the image reading apparatus1, e.g., the image forming apparatus100from being enlarged in the front-rear direction.

Further, in this exemplary embodiment, the restraint part5C restrains the swinging center line L2of the hinge mechanism5A from being displaced relative to the document platen3. Thereby, it is possible to suppress the document cover5from finely vibrating when the driving force is being transmitted to the conveyance mechanism11.

Therefore, it is possible to enable the first gear41and the second gear42to be favorably meshed with each other, so that it is possible to effectively transmit the driving force and to improve the reading precision of an image.

Further, in this exemplary embodiment, the joint part45is a universal joint. Thereby, it is possible to transmit the driving force more effectively, compared to a joint using an elastic member such as a rubber tube and the like.

Further, in this exemplary embodiment, the first gear41and the second gear42are provided at the end portion-side of the document platen3, rather than the hinge mechanism5A, in the direction parallel with the swinging center line L2. Thereby, it is possible to suppress the image reading apparatus1, e.g., the image forming apparatus100from being enlarged and to effectively transmit the driving force.

That is, typically, the reading unit for the conveyed document reading function is provided at the end portion-side of the document platen3. Therefore, if the hinge mechanism5A is provided at the end portion-side of the document platen3, rather than the first gear41and the second gear42, in the direction parallel with the swinging center line L2, it is necessary to separately provide a transmission mechanism that transmits the driving force from the second gear42to the end portion-side of the document platen3.

However, the above-described exemplary embodiment does not require such a transmission mechanism. Therefore, it is possible to suppress the image reading apparatus1, e.g., the image forming apparatus100from being enlarged and to effectively transmit the driving force.

Modifications to Exemplary Embodiments

In the above-described exemplary embodiment, the driving force transmission mechanism13is configured by the planetary gear mechanism including the sun gear15, the planetary gear17, the meshing part19and the like. However, the invention is not limited thereto. For example, the transmission path of the driving force may be switched using an actuator such as a solenoid and the like.

Further, in the above-described exemplary embodiment, all of the first collision surface19E, the second collision surface19F, the third collision surface17F, the fourth collision surface21A and the fifth collision surface23A are the planar surfaces and have the same shape. However, the invention is not limited thereto. For example, all or any one of the first to fifth collision surfaces19E to23A may be curved.

In the above-described exemplary embodiment, the first to fifth collision surfaces19E to23A are provided. However, the invention is not limited thereto. For example, at least one of the first to fifth collision surfaces19E to23A may be omitted.

In the above-described exemplary embodiment, the protrusion19A has the configuration where the first protrusion19C and the second protrusion19D have the same shape, and the other protrusions19A have the same tooth surface shape as the sun gear15. However, the invention is not limited thereto. For example, all the protrusions19A may be made to be the same as the first protrusion19C or second protrusion19D.

In the above-described exemplary embodiment, the first protrusion19C is provided at both sides with the first collision surfaces19E that are symmetric. However, the invention is not limited thereto. For example, it is sufficient that the first collision surface19E is provided to at least a side (a left side of the first protrusion19C, inFIG. 10), which faces the first output gear21, of the tooth surfaces of the first protrusion19C.

In the above-described exemplary embodiment, the second protrusion19D is provided at both sides with the second collision surfaces19F that are symmetric. However, the invention is not limited thereto. For example, it is sufficient that the second collision surface19F is provided to at least a side (a left side of the second protrusion19D, inFIG. 11), which faces the first output gear21, of the tooth surfaces of the second protrusion19D.

In the above-described exemplary embodiment, the meshing part19is the internally-toothed gear19having the plurality of protrusions19A. However, the invention is not limited thereto. For example, the meshing part19with which the protrusions of the planetary gear17of rubber, sponge and the like bite and are thus meshed or meshing part19consisting of only one protrusion19A is also possible.

In the above-described exemplary embodiment, the load generation part has the configuration where the first stopper part25B and the first contacted part25A are contacted. However, the invention is not limited thereto. For example, the load generation part may have a configuration of restraining the first output gear21or another gear, which is rotated in conjunction with the first output gear21, from being rotated.

The moving mechanism9and the conveyance mechanism are not limited to the configurations in the above-described exemplary embodiment and may adopt other configurations.

In the above-described exemplary embodiment, the planetary gear17is supported via the arm17A. However, the invention is not limited thereto. For example, a configuration is also possible in which a shaft of the planetary gear17is slidably inserted into a circular arc-shaped long hole following the revolution path L1.

In the above-described exemplary embodiment, the driving source31is rotated in the forward and reverse directions, thereby rotating the sun gear15in the forward and reverse directions. However, the invention is not limited thereto. For example, a configuration is also possible in which the transmission path of the driving force from the driving source31to the sun gear15is switched using a solenoid and the like, thereby rotating the sun gear15in the forward and reverse directions with the driving source31being rotated in one direction.

In the above-described exemplary embodiment, the rotary shaft directions of the sun gear15, the planetary gear17, the first output gear21and the second output gear23are orthogonal to the placing surface3A. However, the invention is not limited thereto. For example, any one rotary shaft direction may be parallel with the placing surface3A.

In the above-described exemplary embodiment, the meshing part19can be moved along the revolution direction of the planetary gear17. However, the invention is not limited thereto. For example, a configuration where the meshing part19can be moved in a radial direction of the sun gear15or configuration where the meshing part19cannot be moved is also possible.

In the above-described exemplary embodiment, the first output gear21is provided at the opposite side to the second output gear23with the sun gear15being interposed therebetween. However, the invention is not limited thereto.

In the above-described exemplary embodiment, the CIS is used as the imaging unit7. However, the invention is not limited thereto. For example, a CCD may be used as the imaging unit7.

In the above-described exemplary embodiment, the first gear41to the third gear43are the bevel gears. However, the invention is not limited thereto. For example, the first gear41and the second gear42may consist of a worm and a worm wheel.

In the above-described exemplary embodiment, the driving source31and the driving force transmission mechanism13are provided to the document platen3. However, the invention is not limited thereto. For example, the driving source31and the driving force transmission mechanism13may be provided to the document cover5.

Incidentally, when the driving source31and the driving force transmission mechanism13are provided to the document cover5, the driving force is transmitted to not the conveyance mechanism11but the moving mechanism9provided to the document platen3through the second gear42.

Thus, describing the driving force transmission with the configuration of the above-described exemplary embodiment, the driving force from the driving source31is transmitted in order of the third gear43, the second gear42and the first gear41through the driving force transmission mechanism13. Then, the driving force transmitted to the first gear41is transmitted to the moving mechanism9through a transmission mechanism (not shown) such as a gear train and the like.

That is, when the driving source31and the driving force transmission mechanism13are provided to the document cover5, the third gear43of the above-described exemplary embodiment corresponds to the ‘first gear’. The driving force is transmitted from the ‘third gear43corresponding to the first gear’ to the second gear.

In the above-described exemplary embodiment, the rotating direction of the driving force output from the driving force transmission mechanism13is changed twice. However, the invention is not limited thereto. For example, the rotating direction may be changed three or more times.

In the above-described exemplary embodiment, the bevel gear42A provided on the backside of the second gear42is meshed with the third gear43. However, the invention is not limited thereto. For example, the second gear42and the third gear43may be meshed with each other.

In the above-described exemplary embodiment, the swinging center line L2of the hinge mechanism5A and the rotating center line L1of the second gear42are located at the positions deviating towards the document cover5relative to the placing surface3A. However, the invention is not limited thereto. For example, the rotating center line L1and the swinging center line L2may be located at positions opposite to the document cover5relative to the placing surface3A, for example positions deviating towards the below side of the placing surface3A.

In the above-described exemplary embodiment, the joint part45configured by the universal joint is provided. However, the invention is not limited thereto. For example, the joint part45may be omitted or may be configured by an elastic member such as rubber tube and the like.

In the above-described exemplary embodiment, the first support part47is mounted to the second support part49. However, the invention is not limited thereto. For example, the second support part49may be mounted to the first support part47.

In the above-described exemplary embodiment, the second support part49is mounted to the document cover5. However, the invention is not limited thereto. For example, the second support part49may be mounted to the document platen3.

In the above-described exemplary embodiment, the second support part49has the shaft shape. However, the invention is not limited thereto. For example, the second support part49may have the same configuration as the first support part47.

In the above-described exemplary embodiment, the first support part47is detachably mounted to the second support part49with the first gear41being mounted to the first support part47. However, the invention is not limited thereto. For example, the first support part47and the first gear41may be independently and detachably mounted to any one of the second support part49, the document cover5and the document platen3.

In the above-described exemplary embodiment, the third gear43is provided at the front of the rotating center line L1of the second gear42. However, the invention is not limited thereto. For example, the third gear43may be arranged at the rear of the rotating center line L1.

In the above-described exemplary embodiment, the swinging center line L2of the hinge mechanisms5A,5B is restrained from being displaced relative to the document platen3. However, the invention is not limited thereto. For example, it can be separation/connection displaced relative to the document platen3through an elastic member such as a spring and the like.

In the above-described exemplary embodiment, the first gear41and the second gear42are provided at the end portion-side of the document platen3, rather than the hinge mechanism5A, in the direction parallel with the swinging center line L2. However, the invention is not limited thereto. For example, the first gear41and the second gear42may be arranged between the hinge mechanism5A and the hinge mechanism5B.

In the above-described exemplary embodiment, the first gear41is arranged at the part corresponding to the range A, in which the gears11G to11J are provided, in the direction parallel with the rotating center line L1of the second gear42. However, the invention is not limited thereto. For example, the first gear may be also arranged at a position deviating from the range A.

In the above-described exemplary embodiment, the image forming unit50of the electrophotographic type is adopted. However, the invention is not limited thereto. For example, the image forming unit50of an inkjet type may be also adopted.

In the above-described exemplary embodiment, the invention is applied to the image forming apparatus100having the image reading apparatus1and the image forming unit50. However, the invention is not limited thereto. For example, the invention may be also applied to a monolithic image reading apparatus.

Further, the invention is not limited to the above-described exemplary embodiment, and other modifications may be made within a scope of the invention as defined in the following claims.