Image reading apparatus provided with an exchangeable image reading portion

A image reading apparatus 4 includes the exchangeable image reading portion 38, the document transportation path 30 curved so as to move around the image reading portion 38, the skew correction rollers 35 in the hosing 3a. The skew correction rollers 35 are arranged on the document transportation path 30 at the transportation upstream side with respect to the reading position 46 of the image reading portion 38. The image reading portion 38 passes through the document transportation path 30 at the transportation upstream side with respect to the skew correction rollers 35 so as to be detached from and attached to the housing 3a.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on application No. 2010-18478 filed in Japan, the entire content of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sheet through type image reading apparatus which reads an image on a document while being transported by an image reading portion which cannot be moved.

2. Related Art

In a sheet through type image reading apparatus, an exchangeable image reading portion and a document transportation path which is curved so as to move around the image reading portion when viewed from the side are included in a housing. As an image reading portion employed in an image reading apparatus of this type, a Contact Image Sensor (CIS) which is light weight and small in size is used in many cases so as to be arranged in a narrow space. The CIS has a narrow focal depth when an image is read. Therefore, an image reading roller is provided so as to be opposed to a reading position of the CIS and a space between the CIS and the reading roller is kept to be narrow so that an image on a document which passes through the space is read. When an image is read, the reading position of the CIS and a document is slid contact with each other so as to easily generate static electricity. In particular, static electricity is significantly generated under an environment of low humidity. Such static electricity may cause malfunction or failure of the CIS. Therefore, exchange frequency of the CIS is high among electrical parts constituting the image reading apparatus.

In terms of this point, a following configuration has been disclosed in Japanese Unexamined Patent Publication No. 2004-336270. That is, a reading roller which is arranged so as to be opposed to a reading position of a CIS is detachably inserted to an opening. The opening is provided at a lower surface side of a housing. Further, the CIS is detached from the opening from which the reading roller has been detached in a downward direction. With such configuration, there is an advantage that workability when a service person detaches the CIS in a market can be improved.

However, in the above-described conventional configuration, the following problem is caused. That is, the reading roller which is arranged so as to be opposed to the reading position of the CIS can be detachably inserted in the above-described conventional configuration. Therefore, every time after the CIS is exchanged, the CIS is required to be attached while positioning the CIS and the reading roller at high accuracy and adjusting a space between the CIS and the reading roller and attachment postures thereof. Accordingly, even if the CIS is easily detached, time and effort for attaching the CIS are required (workability for attachment is bad).

Further, when a sufficient attachment accuracy is not ensured because attachment positions of the CIS and the reading roller are deviated, there collaterally arises a problem that an image reading accuracy by the CIS is deteriorated, or skew of a document or a paper jam is caused. That is to say, when the CIS is exchanged, it is preferable that mechanisms represented by the reading roller, which deeply relate to a document transportation accuracy or an image reading accuracy, be not attached and detached if possible. As the mechanisms which deeply relate to a document transportation accuracy or an image reading accuracy, rollers, guiding members, and the like which are arranged at a transportation downstream side with respect to a skew correction roller which corrects skew of a document are exemplified.

SUMMARY OF THE INVENTION

A technical object of the invention is to eliminate the above problems. The present inventors have studied repeatedly in order to improve the conventional techniques and have achieved the invention. The invention has multiphase applications.

An image reading apparatus according to an aspect of the invention includes an exchangeable image reading portion, a document transportation path which is curved so as to move around the image reading portion, and a skew correction roller which is arranged on the document transportation path at a transportation upstream side with respect to a reading position of the image reading portion, in a housing. In the image reading apparatus, the image reading portion passes through the document transportation path at the transportation upstream side with respect to the skew correction roller so as to be detached from and attached to the housing.

A pair of guiding members which guide transportation of a document may be provided between a sheet feeding roller and the skew correction roller on the document transportation path. In this case, it is preferable that the document transportation path at the transportation upstream side with respect to the skew correction roller be opened and the image reading portion be exposed from the opening by detaching both the guiding members from the positions constituting the document transportation path.

An opening and closing cover which can be opened and closed so as to expose or cover the document transportation path at the transportation upstream side with respect to the reading position of the image reading portion may be provided. In this case, it is preferable that the opening and closing cover at the side of the document transportation path constitute the one guiding member and the other guiding member be detachably attached to the housing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment in which the invention is embodied will be described with reference to drawings. Note that expressions indicating specific directions and positions (for example, “right and left”, and “up and down” or the like) used in the following description are only used for convenience of description and are not intended to limit a technical range of the invention. An image reading apparatus4according to an embodiment is mounted on a Multi Function Printer (hereinafter, referred to as MFP)1as an example of an image forming apparatus.

1. Outline of Image Forming Apparatus

The MFP1as shown inFIG. 1has multiple functions including a copying function, a scanner function, a printer function, and a facsimile function. The MFP1can transmit and receive data through a network (communication network) such as a LAN or a telephone network. That is to say, the MFP1can output image data read from a document to another computer through a network or input image data from another computer through a network so as to execute printing based on the image data. Further, the MFP1can transmit and receive facsimile data.

The image reading apparatus4which includes a scanner portion2and an automatic document feeder3(hereinafter, referred to as ADF) is provided on an upper portion of an apparatus main body1aof the MFP1. The image reading apparatus4is configured as follows. The scanner portion2and the ADF3are operated in synchronization with each other so as to optically read an image from each document set on the ADF3. With this operations, image data is acquired. That is to say, the image reading apparatus4is configured such that the ADF3transports documents one by one toward the scanner portion2and the scanner portion2reads an image when a document passes through a predetermined reading position so that image data is acquired.

A sheet feeding portion6which accommodates recording materials is provided at a lower portion of the apparatus main body1a. An image forming portion5is provided between the image reading apparatus4and the sheet feeding portion6of the apparatus main body1a. The image forming portion5prints a toner image onto the recording material. The sheet feeding portion6supplies the recording materials one by one to the image forming portion5. The image forming portion5prints a toner image onto the recording material based on the image data acquired by the image reading apparatus4or through a network. A concaved space between the image reading apparatus4and the image forming portion5on the apparatus main body lacorresponds to a discharged sheet storing portion7. The recording material onto which a toner image has been printed by the image forming portion5is discharged to the discharged sheet storing portion7.

An operation panel8is provided on a front side (anterior surface side) of the apparatus main body1a. The operation panel8has a plurality of keys (buttons). A user operates the keys while checking a display screen or the like on the operation panel8so as to perform setting about a function selected from various functions of the MFP1or instruct the MFP1to execute operations.

2. Configuration of Image Reading Apparatus

Next, a configuration of the image reading apparatus4is described with reference mainly toFIG. 2. The ADF3includes a sheet feeding tray31on which a plurality of documents M are placed (set). The documents M placed on the sheet feeding tray31are fed one by one starting from an uppermost document to a document transportation path30by a pick up roller32and a sheet feeding roller pair33. Then, the document M is transported to a resist roller pair35as skew correction rollers through an intermediate roller pair34. The resist roller pair35adjusts one document M transported to be in a predetermined posture and transports the document M toward a first transportation roller pair36at a predetermined timing. Then, the document M is transported on a slit glass21of the scanner portion2by the first transportation roller pair36. The slit glass21is formed into a small-width long plate form which is long in a main scanning direction perpendicular to a document transportation direction and is transparent.

When the document M passes through the position on the slit glass21, a first document reading unit22reads an image on a downward-facing first face (surface) on the document M. Note that the first document reading unit22is positioned at a lower side of the slit glass21. A second transportation roller pair37, a second document reading unit38, a third transportation roller pair39, and a sheet discharge roller40are arranged on the document transportation path30at the transportation downstream side with respect to the position on the slit glass21. The second document reading unit38corresponds to an image reading portion as described in Claims. The document M which has passed through the position on the slit glass21is fed to a position just under the second document reading unit38by the second transportation roller pair37. Then, the second document reading unit38reads an image on an upward-facing second face (back surface) on the document M while the document M is passing through the position. The document M which has passed through the position just under the second document reading unit38is discharged on a sheet discharge tray41by the third transportation roller pair39and the sheet discharge roller40. The sheet discharge tray41is positioned at a lower side of the sheet feeding tray31.

As is obvious fromFIG. 2, the document transportation path30in the ADF3is a path from the sheet feeding tray31to the sheet discharge tray41through the pickup roller32, the sheet feeding roller pair33, the intermediate roller pair34, the resist roller pair35, the first transportation roller pair36, the position on the slit glass21, the second transportation roller pair37, the position just under the second document reading unit38, the third transportation roller pair39, and the sheet discharge roller40. The document transportation path30is a substantially horseshoe-shaped (curved) path when viewed from the side. The second document reading unit38is arranged at an inner side of the document transportation path30which is the horseshoe-shaped path when viewed from the side. In other words, the document transportation path30is curved so as to move around the second document reading unit38when viewed from the side.

A rotatable cleaning roller42is provided at an upper side of the slit glass21. The cleaning roller42rotationally drives in a state where there is no document M on the slit glass21so as to remove foreign matters such as paper powder adhered onto the slit glass21. For example, when a plurality of documents M are continuously transported in the ADF3, the cleaning roller42rotationally drives in a time interval since a previous document M has passed through the position on the slit glass21until a subsequent document M reaches to the position so as to clean the slit glass21. A reading roller43is rotatably provided at a side opposite to the second document reading unit38with respect to the document transportation path30. The reading roller43is an example of a white reference member for shading correction.

On the other hand, the above-described slit glass21and a platen glass23are provided on an upper surface of the scanner portion2. The platen glass23is formed into a flat plate form having a large width and is transparent. The above-described first document reading unit22is provided in the scanner portion2. The first document reading unit22reads an image on the first face of a document M which passes through the position on the slit glass21and an image on a document M placed on the platen glass23. Further, the first document reading unit22includes a scanning unit24, a driving unit25, an image forming lens26and a first line sensor27. The scanning unit24has a light source24aand a reflection mirror24b. The driving unit25has a pair of reflection mirrors25a,25b.

When a document M passes through the position on the slit glass21, light is irradiated toward a first face of the document M from the light source24ain a state where the scanning unit24and the driving unit25are fixed. Then, the reflection light from the first face of the document M is introduced to the first line sensor27through the reflection mirror24b, both of the reflection mirrors25a,25band the image forming lens26so that an image is formed. Further, when an image on the document M placed on the platen glass23is read, light is irradiated toward a lower surface (facing surface) of the document M from the light surface24awhile the scanning unit24and the driving unit25move in the sub scanning direction. Then, the reflection light thereof is introduced to the first line sensor27so that an image is formed. The first line sensor27is formed with a Charge Coupled Device (CCD) having a plurality of photoelectric conversion elements which are arranged along the main scanning direction. The first line sensor27converts the formed optical image to an image signal and outputs the image signal to an image processor28. In the image processor28, the input image signal is subjected to an analog processing, an A/D conversion, a shading correction, an image compressive processing, and the like so as to generate a digitalized image data. Then, the digitalized image data is output to the image forming portion5.

The second document reading unit38arranged in the ADF3in an unmovable manner reads an image on the second face of the document M which passes through a position on the reading roller43. The second document reading unit38includes a pair of light sources44a,44band a second line sensor45(see,FIG. 3). When a document M passes through the position on the reading roller43, light is irradiated toward the second face of the document M from both of the light sources44a,44b. Then, the reflection lights thereof are received by the second line sensor45so that an image is formed. The second line sensor45is formed with a Contact Image Sensor (CIS) having a plurality of photoelectric conversion elements which are arranged along the main scanning direction. The second line sensor45also converts the formed optical image to an image signal and outputs the image signal to the image processor28in the same manner as the first line sensor27. A side of the second document reading unit38, which faces the reading roller43, corresponds to a reading position46(reading surface).

A cover member50facing the second document reading unit38is provided at a bottom side of the ADF3. The cover member50can be opened and closed rotationally about a supporting point51provided at a transportation downstream side. An inner surface of the cover member50at the side of the document transportation path30functions as a guiding surface constituting a part of the document transportation path30at the transportation downstream side in a state where the cover member50is closed. On the cover member50, one (lower side) of the second transportation rollers37, the reading roller43, and one (lower side) of the third transportation rollers39are rotatably assembled in parallel with each other so as to be unitized. Opening trenches (not shown) corresponding to each of the rollers37,43,39are formed on the inner surface of the cover member50at the side of the document transportation path30. A part of an outer circumference of each of the rollers37,43,39is exposed from each of the opening trenches. With the opening/closing rotation of the cover member50, a range from the second transportation roller pair37to the third transportation roller pair39on the document transportation path30is exposed or covered.

Although not described in detail, a latch claw which engages or disengages with respect to a latch reception fragment is provided at each of side plate portions of the cover member50in the main scanning direction. The latch reception fragment is provided at the side of the ADF3. The cover member50is made into an opened rotatable state (can be shifted into an opened state) or is made into a closed state by engaging or disengaging the latch claws with respect to the latch reception fragments. The latch claws are engaged or disengaged with respect to the latch reception fragment with the operations by an opening and closing gripper provided on the cover member50.

The reading roller43as an example of a white reference member is extended in the main scanning direction and is pivotally supported in a rotatable manner by the cover member50. An outer circumferential portion of the reading roller43is formed with a curved surface (roller surface) and a flat surface. Although not described in detail, the curved surface is divided into a white reference surface for shading correction and a sheet feeding surface. The white reference surface is extended in a belt form along the main scanning direction. The sheet feeding surface is in contact with the document M so as to guide the document M when the document M is transported. On the other hand, a cleaning brush made of a large number of brush hairs is implanted on the flat surface.

The sheet feeding surface of the reading roller43is normally exposed from the opening trench of the cover member50. For example, when the document M passes through the position just under the second document reading unit38, the sheet feeding surface is in contact with the document M so as to guide the document M. Further, when shading correction is performed, the reading roller43rotationally drives so as to make the white reference surface expose from the opening trench of the cover member50. The cleaning brush on the flat surface is configured to be made into contact with the second document reading unit38appropriately by the rotational driving of the reading roller43in a state where the document M is not present at a position just under the second document reading unit38. Foreign matters such as paper powder adhered to the second document reading unit38are swept by a cleaning brush43cso as to be removed.

An opening and closing cover55is provided at an upper surface of the ADF3. The opening and closing cover55can be opened and closed so as to expose or cover the document transportation path30at the transportation upstream side with respect to the reading position of the second document reading unit38. The opening and closing cover55according to the embodiment can be opened and closed rotationally about a hinge portion56which is parallel with the main scanning direction in the vicinity of the first transportation roller pair36. An inner surface of the opening and closing cover55at the side of the document transportation path30functions as an outer side guiding member63(which will be described in detail) constituting a part of the document transportation path30at the transportation upstream side in a state where the opening and closing cover55is closed. On the opening and closing cover55, one (upper side) of the intermediate rollers34and one (upper side) of the resist rollers35are rotatably assembled in parallel with each other so as to be unitized. Note that the one of the intermediate rollers34and the one of the resist rollers35are long in the main scanning direction. With the opening/closing rotation of the opening and closing cover55, a range from the intermediate roller pair34to the vicinity of a position immediately before the first transportation roller pair36on the document transportation path30is exposed or covered.

3. Detachment and Attachment Configurations of Second Document Reading Unit

Next, detachment and attachment configurations of the second document reading unit38with respect to the ADF3are described with reference toFIG. 3toFIG. 11. As is obvious from the above description, the ADF3includes the second document reading unit38as an image reading portion, the document transportation path30curved so as to move around the second document reading unit38when viewed from the side, the resist roller pair35as skew correction rollers in the hosing3a. The resist roller pair35is arranged on the document transportation path30at the transportation upstream side with respect to the reading position46of the second document reading unit38.

An accommodation chamber60is provided in the housing3aof the ADF3. The accommodation chamber60is divided in the main scanning direction by a right partitioning side plate61and a left partitioning side plate62which are positioned at both sides of the accommodation chamber60in the main scanning direction. Members relating to document transportation and image reading of the document are positioned in the accommodation chamber60(between the right partitioning side plate61and the left partitioning side plate62) and supported by the right partitioning side plate61and the left partitioning side plate62except the other (lower side) of the intermediate rollers34. The members relating to document transportation and image reading of the document are pickup roller32, the sheet feeding roller pair33, the other (lower side) of the intermediate rollers34, the other (lower side) of the resist rollers35, the first transportation roller pair36, the cleaning roller42, the other (upper side) of the second transportation rollers37, the second document reading unit38, the other (upper side) of the third transportation rollers39, and the sheet discharge roller40.

As shown inFIG. 3toFIG. 5, a pair of guiding members63,64which guide a document M to the resist roller pair35are provided between the sheet feeding roller pair33and the resist roller pair35in the upper portion of the accommodation chamber60. Both of the guiding members63,64constitute a part of the document transportation path30at the transportation upstream side (path between the sheet feeding roller pair33and the resist roller pair35). An inner surface of the opening and closing cover55at the side of the document transportation path30serves a function as the outer side guiding member63in both of the guiding members63,64. The inner side guiding member64is a substantially flat plate member which covers an upper side of the second document reading unit38. The inner side guiding member64is detachably attached to bracket fragments65,66with locking screws67,68. The bracket fragments65,66are provided in a projecting manner at the inner surface sides of the right partitioning side plate61and the left partitioning side plate62, respectively. In a state where the opening and closing cover55is closed, the outer side guiding member63which is an inner surface of the opening and closing cover55at the side of the document transportation path30and the inner side guiding member64are opposed to each other with a slight space.

The other (lower side) of the intermediate rollers34is arranged at the lower side of the inner side guiding member64in a rotatable and detachable manner. It is to be noted that the intermediate roller34at the lower side of the inner side guiding member64is referred to as a lower intermediate roller34for the convenience in the description below. In this case, one end (right end) of a shaft portion on the lower intermediate roller34is inserted to a small diameter hole in a detachable and rotatable manner. The small diameter hole is formed on a flange provided by cutting a part of the inner side guiding member64into an U-shaped form and bending the cut inner side guiding member64downward. The other end of the lower intermediate roller34is held by the other flange extending from the edge of the inner side guiding member64so as to bend downward. On the other hand, the other end (left end) of the shaft portion on the lower intermediate roller34is detachably coupled to a coupling71inserted to a large diameter hole70of the left partitioning side plate62(see,FIG. 5). A support shaft72projecting outward from the coupling71is rotatably supported by a driving portion73between the housing3aand the left partitioning side plate62. A plurality of opening holes74are formed on the inner side guiding member64. Some parts of the outer circumferential side of the lower intermediate roller34are exposed from the opening holes74.

It is to be noted that the intermediate roller pair34is provided in relation to sizes of documents which can be fed in the MFP1according to the embodiment. The intermediate roller pair34may not be provided when a distance from the sheet feeding roller pair33to the resist roller pair35on the document transportation path30is short.

As shown inFIG. 3,FIG. 6, andFIG. 7, the ADF3is configured to open the document transportation path30at the transportation upstream side with respect to the resist roller pair35by detaching both of the guiding members63,64from positions constituting the document transportation path30. Further, the second document reading unit38is exposed from the opening80. In the embodiment, if the inner side guiding member64and the lower intermediate roller34are detached after the opening and closing cover55is opened, the second document reading unit38appears (can be seen) from the opening80covered by the inner side guiding member64.

The second document reading unit38is long in the main scanning direction and is detachably attached to the right partitioning side plate61and the left partitioning side plate62in an exchangeable manner. When the second document reading unit38is exchanged (attached or detached), the second document reading unit38is inserted or removed from the document transportation path30at the transportation upstream side with respect to the resist roller pair35. That is, the second document reading unit38is inserted or removed from the opening80covered by the inner side guiding member64at the time of the exchange. Namely, the second document reading unit38is passed through the document transportation path30at the transportation upstream side with respect to the resist roller pair35so as to be attached to and detached from the housing3a(the right partitioning side plate61and the left partitioning side plate62).

In this case, in order to easily insert and detach the second document reading unit38from the opening80, a width Ls of the second document reading unit38in the sub scanning direction is sufficiently shorter than a width Lg of the inner side guiding member64in the sub scanning direction (see,FIG. 3). In addition, in order to achieve both of reduction of the ADF3in size and sufficient ensuring of an effective reading region of the second document reading unit38, a length Lm of the second document reading unit38in the main scanning direction is longer than an internal dimension Lin of the right partitioning side plate61and the left partitioning side plate62(see,FIG. 10). One end (right end) of the second document reading unit38in the main scanning direction penetrates through a right rectangle hole81in a detachable manner. The right rectangle hole81is formed on a lower side of the small diameter hole69on the right partitioning side plate61. On the other hand, the other end (left end) of the second document reading unit38in the main scanning direction penetrates through a left rectangle hole82in a detachable manner. The left rectangle hole82is formed on a lower side of the large diameter hole70on the left partitioning side plate62.

A fixing plate fragment83is provided so as to project outward on an outer surface side of the right partitioning side plate61at the upper side of the right rectangle hole81. The projected part of the second document reading unit38from the right rectangle hole81is detachably attached to the fixing plate fragment83at the outer surface side of the right partitioning side plate61with the locking screw84from the upper side.

A position fixing plate85is provided on the upper surface of the other end (light end side) of the second document reading unit38in the main scanning direction in a standing manner. The position fixing plate85abuts against an inner surface of the left partitioning side plate62. Positioning pins87are provided so as to project outward on the abutment surface of the position fixing plate85. The positioning pins87are fitted into positioning holes86which are formed on the left partitioning side plate62. Further, a threaded screw hole89is provided on the position fixing plate85. The threaded screw hole89is fitted to a through hole88of the left partitioning side plate62in a state where the positioning pins87are fitted into the positioning holes86of the left partitioning side plate62. A locking screw90is inserted into the through hole88and the threaded screw hole89from the outer left side in a state where the position fixing plate85is superimposed with the inner surface side of the left partitioning side plate62and the positioning pins87of the position fixing plate85are fitted into the positioning holes82of the left partitioning side plate62. With this, the other end (left end) of the second document reading unit38in the main scanning direction is detachably supported by the left partitioning side plate62. By employing such configuration, the second document reading unit38is positioned while ensuring an appropriate focal depth and posture with respect to the reading roller43. Further, the second document reading unit38is supported by the right partitioning side plate61and the left partitioning side plate62such that the second document reading unit38is suspended so as not to deviate in any directions.

4. Operation Effect

In the above configuration, when the second document reading unit38is detached, the opening and closing cover55is opened at first. Then, the locking screws67,68are loosened and removed so that coupling between both of the bracket fragments65,66and the inner guiding member64is released. Then, the inner guiding member64and the lower intermediate roller34are collectively detached so as to expose (open) the opening80.

Thereafter, the locking screws84,90provided at outer sides of the right partitioning side plate61and the left partitioning side plate62are all loosened and removed (see,FIG. 10). Then, the second document reading unit38is deviated toward the right rectangle hole81of the right partitioning side plate61in such a manner that the positioning pins87of the position fixing plate85are pulled out of the positioning holes86of the left partitioning side plate62. Further, the second document reading unit38is detached from the ADF3in such a manner that the other end (left end, side at which the position fixing plate85is provided) of the second document reading unit38in the main scanning direction is pulled up from the opening80(see,FIG. 11). When the second document reading unit38is attached, it is sufficient that inverse procedures of the above procedures are performed.

As is obvious from the above description, with the above configurations, the image reading apparatus4includes the exchangeable image reading portion38, the document transportation path30curved so as to move around the image reading portion38, the skew correction rollers35in the hosing3a. The skew correction rollers35are arranged on the document transportation path30at the transportation upstream side with respect to the reading position46of the image reading portion38. In the image reading apparatus4, the image reading portion38passes through the document transportation path30at the transportation upstream side with respect to the skew correction rollers35so as to be detached from and attached to the housing3a. Therefore, the image reading portion38(and peripheral associated parts) can be easily exchanged without detaching mechanisms which are arranged at a transportation downstream side with respect to the skew correction rollers35, that is, mechanisms which deeply relate to a document transportation accuracy or an image reading accuracy (rollers, guiding members, and the like).

Accordingly, the following effects can be obtained with the above configurations. That is, maintenance workability of the image reading portion38(and peripheral associated parts) can be improved and positioning accuracy of the image reading portion38with respect to mechanisms which deeply relate to a document transportation accuracy or an image reading accuracy can be ensured. Further, a risk that failures such as deterioration in the image reading accuracy, skew of documents M and paper jam are caused when the image reading portion38is exchanged can be suppressed.

Further, a pair of guiding members63,64which guide transportation of a document M are provided between the sheet feeding roller pair33and the skew correction rollers35on the document transportation path30. Further, both the guiding members63,64are detached from the positions constituting the document transportation path30. Therefore, the document transportation path30at the transportation upstream side with respect to the skew correction rollers35is opened and the image reading portion38is exposed from the opening80. With the opening80formed by detaching the guiding members63,64, a large access space for the image reading portion38can be ensured. Accordingly, a large effect for improving maintenance workability of the image reading portion38(and peripheral associated parts) can be obtained.

In addition, the opening and closing cover55is provided on the housing3a. The opening and closing cover55can be opened and closed so as to expose or cover the document transportation path30at the transportation upstream side with respect to the reading position46of the image reading portion38. The opening and closing cover55at the side of the document transportation path30constitutes the one guiding member63and the other guiding member64is detachably attached to the housing3a. Therefore, when paper jam is removed, for example, a configuration of the opening and closing cover55to be opened is effectively utilized so that the document transportation path30at the transportation upstream side with respect to the skew correction roller35can be opened. Accordingly, a configuration in which both of the guiding members63,64are detached from the positions constituting the document transportation path30can be simplified so as to contribute to cost reduction.

Some examples relating to the invention have been described above, but the invention is not limited to the above description. For example, in the above embodiment, a case where the image forming apparatus MFP1is an apparatus having a multiple functions including a copying function, a facsimile function, a printer function, and a scanner function is described. However, the image forming apparatus MFP1is not required to have all the plurality of functions. In particular, the image reading apparatus4can be applied to an apparatus including at least one function of the copying function, the facsimile function, and the scanner function. Further, each of the guiding members63,64may be opened or closed rotationally or detachably attached. In short, it is sufficient that each of the guiding members63,64have a configuration so as to be separated from a position constituting the document transportation path30. Moreover, a configuration of each part is not limited to the embodiment shown in the drawings and can be variously modified in a range without departing from a scope of the invention.