Abstract:
One aspect of the invention provides an image reading apparatus including: a document placement portion on which a document is allowed to be placed; a display portion, at least a part of which is transmissive of light; an image reading unit movable along a first direction below the document placement portion and comprising an light emitting unit configured to emit light; and a control unit operable to control the image reading unit in a plurality of operation modes. The plurality of operation modes include a first operation mode that allows the image reading unit to be positioned at a first position corresponding to the display portion and cause the light emitting unit to emit the light, and the display portion is transmissive of the light emitted from the light emitting unit at the first position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2006-349784, filed on Dec. 26, 2006, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     One aspect of the present invention relates to a document reading apparatus of the so-called flat bed type for reading a document placed on a document placement table. 
     BACKGROUND 
     There is an image reading apparatus of the so-called flat bed type, which reads a document placed on a glass plate fixed to a document placement table with a record surface of the document set downward and includes an image reading unit (image scanner device) configured to scan the document and arranged in a lower portion of the glass plate. 
     In such an image reading apparatus, it is necessary to place a document in a proper position with respect to the glass plate (image scanner device) in order to correctly recognize a size of the document and read the document. Therefore, a positioning member for guiding a position of the document is arranged in the periphery of the glass plate. The positioning member is generally disposed in a state of slightly upward protruding beyond the glass plate and the side of the document is abutted on the positioning member to perform positioning. 
     In order to improve operability of positioning, for example, in JP-A-2004-144832, a mark portion for guiding a position to place a document is printed or inscribed on a surface of a positioning member and in addition, a mark portion for guiding a placement position is formed on a glass plate. Plural kinds of mark portions are disposed for documents with different sizes, so that a user can align correctly the document of each size. 
     However, in the case of the mark portion as shown in JP-A-2004-144832, since the placement is not always performed in sufficiently bright environment, it is difficult to find the mark portion when the periphery is dark and the document cannot be aligned speedily. 
     On the other hand, JP-A-2002-214977 discloses an image reading apparatus including an arranging light emission device in a positioning member. In the image reading apparatus, when a document is aligned with a glass plate, reference positions (for example, a back side reference for aligning with the corners of the back side of the glass plate, a center reference for aligning with the center, or a front reference for aligning with the corners of the front side) vary depending on models. As a result of that, for example, when a document is aligned by a center reference or a front reference in spite of an apparatus of a back side reference, trouble in which most of the document cannot be read is caused. 
     Therefore, in JP-A-2002-214977, a reference lamp is disposed as the light emission device in the vicinity of a reference position in the positioning member so that a user can recognize its reference position without making a mistake. Concretely, for example, in an image reading apparatus of a back side reference, when a cover is opened, the reference lamp disposed in the positioning member in the vicinity of a back side reference position lights roundly (see FIG. 2 of JP-A-2002-214977). Consequently, the user can speedily recognize that the apparatus is the apparatus of the back side reference and can place the document on the glass plate without mistaking the reference position. 
     SUMMARY 
     For example, when the image reading apparatus adopts a center reference, a center position (center line) of a document is aligned with a reference position and it is difficult to accurately grasp the center line of the document by only making a visual check. Therefore, it is normally constructed so as to align two sides orthogonal to one side of the document with a mark portion disposed in a positioning member while abutting one side of the document on the positioning member. 
     In JP-A-2002-214977 described above, the reference lamp is used, so that it can be speedily recognized that the reference is a center reference even when environment of the periphery is dark. However, only the reference lamp emits light and the mark portion does not emit light, so that it is difficult to accurately align when the periphery is dark. 
     Also, in JP-A-2002-214977, a light source is necessary for the reference lamp which is the light emission device (the light source is not described concretely in JP-A-2002-214977) and in addition, multiple light sources are required in the case of attempting to emit light the mark portion. As a result of that, the cost of the image reading apparatus increases and also space for arranging multiple light sources is required. 
     An object of one aspect of the invention is to provide an image reading apparatus capable of emitting light to the outside of the image reading apparatus while suppressing an increase in cost. 
     According to an aspect of the invention, there is provided an image reading apparatus including: a document placement portion on which a document is allowed to be placed; a display portion, at least a part of which is transmissive of light; an image reading unit movable along a first direction below the document placement portion and comprising an light emitting unit configured to emit light; and a control unit operable to control the image reading unit in a plurality of operation modes, wherein the plurality of operation modes include a first operation mode that allows the image reading unit to be positioned at a first position corresponding to the display portion and cause the light emitting unit to emit the light, the display portion being transmissive of the light emitted from the light emitting unit at the first position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a state of opening a cover body of an image reading apparatus according to an embodiment of the invention; 
         FIG. 2  is a plan view of a state of removing the cover body; 
         FIG. 3  is a sectional view taken on line III-III of  FIG. 2 ; 
         FIG. 4A  is a side sectional view of a mark portion, and  FIGS. 4B to 4D  are side sectional views of modified examples of mark portions; 
         FIG. 5  is a flowchart showing an operation of an image reading unit; 
         FIG. 6  is a modified example of an operation of an image reading unit; 
         FIG. 7  is another modified example of an operation of an image reading unit; and 
         FIG. 8  is a block diagram illustrating an electric configuration of the image reading device. 
     
    
    
     DESCRIPTION 
     An embodiment of the invention will be described below.  FIG. 1  is a perspective view of an image reading apparatus  1 . The image reading apparatus  1  may be applied to a single scanner device or may be applied to an image reading unit of a multi function device having plural functions such as a facsimile function, a copy function, a printer function and a scanner function. 
     In the image reading apparatus  1 , a document placement table  3  on which a document is placed is disposed in the upper side of a body case  2 , and a CIS (Contact Image Sensor) that is an image scanner device as an image reading unit  4  is movably arranged under the table  3  as shown in  FIG. 1 . 
     As shown in  FIG. 8 , the image reading apparatus  1  includes an ASIC (Application Specific Integrated Circuit)  76  connected to an opening and closing sensor  31 , the image reading unit  4 , an LCD (Liquid Crystal Display)  41 , an operation unit  51 , various interfaces (a LAN interface  61 , an USB interface  62 , and a parallel interface  63 ), a control unit  70  and a step motor  81 . 
     The control unit  70  is configured by a microprocessor and includes a CPU  71 , a ROM  72 , a RAM  73  and a flash memory  74 , which are connected via a bus  75  to the ASIC  76 . The ROM  72  stores a program to be executed by the CPU  71  and data necessary for it (such as operation modes of the image reading unit  4 ). The RAM  73  functions as a work region when the CPU  71  executes the program. The flash memory  74  is a memory retaining data even after the power turns off and stores various data such as setting data. 
     The LCD  3  includes a display screen for displaying various kinds of information thereon. The operation keys  4  accept an input from a user for operating the image reading apparatus  1 . 
     The document placement table  3  includes a glass plate  5  (a transparent member), and a frame body  6  with thin plate shape arranged and overlapped over the glass plate  5 . In addition, in  FIG. 1 , members arranged under the glass plate  5  are also displayed by solid lines. Here, the frame body  6  is constructed by combining plural plate-shaped members so that the inner periphery and the outer periphery show a rectangular shape when viewed from the plane, and the portion of the glass plate  5  exposed to the inside of the inner periphery of the frame body  6  in a rectangular shape when viewed from the plane forms a document placement portion  7  on which a document is placed. The frame body  6  is substantially opaque. A direction parallel to a short side of the document placement portion  7  is set in an X-axis direction and a direction parallel to a long side is set in a Y-axis direction. 
     A frame of the frame body  6  adjacent to one short side (an example of a first side) parallel to the X-axis of the document placement portion  7  is used as a positioning member  10  (an example of a second portion) for positioning a document placed on the document placement portion  7 . As a result of that, the positioning member  10  is arranged adjacently to the document placement portion  7 . Since the frame body  6  is arranged and overlapped over the glass plate  5 , the positioning member  10  upward protrudes beyond the document placement portion  7 . A side surface of the side of the document placement portion  7  of the positioning member  10  forms a surface (abutting surface)  10   a  (an example of a positioning portion) on which a document P at the time of alignment abuts, and is used for positioning of a Y-axis direction of the document P. 
     The image reading unit  4  arranged under the glass plate  5  is elongated in the X-axis direction, and its length is set in accordance with a reading region of the X-axis direction in the document placement portion  7  and is herein set at about the same length dimension as that of the short side of the document placement portion  7 . A shaft portion  8  extending in the Y-axis direction is disposed under the glass plate  5  and near a center line of width of the X-axis direction, and the image reading unit  4  is disposed so as to slide along the shaft portion  8  and reciprocate in the Y-axis direction. The image reading unit  4  is disposed so as to be able to move along a back surface of the positioning member  10  as well as move along a back surface of the document placement portion  7  used as a reading region in order to read the document P. 
     As shown in  FIGS. 1 and 8 , the image reading unit  4  includes a light emitting unit  41  for emitting light to a document placed on the glass plate  5 , and a light receiving unit  42  for receiving light reflected on the document P. Movement and light emission (lighting) of the image reading unit  4  are controlled by a control unit  70 . In this embodiment, the CIS is adopted as the image reading unit  4 , and the light emitting unit  41  includes a light source of LEDs of three colors of R (red), G (green) and B (blue), and the light receiving unit  42  includes an image pickup device (C-MOS sensor). 
     As shown in  FIG. 3 , light emission of the light emitting unit  41  includes first light emission (an example of a third operation mode) in a white reference position  21  (an example of a second position), second light emission (an example of a first operation mode) in a mark position  24  (an example of a first position) and reading light emission (an example of a second operation mode) for reading an image in addition to light emission for searching a reference position (HP, home position)  20  used as a reference point of movement in the Y-axis direction. 
     The image reading apparatus  1  includes the step motor  81 , so that a position of a target in the Y-axis direction of the image reading unit  4  can be reached by calculating the number of steps after emitting light and detecting the reference position  20 . In the light emission for searching this reference position  20 , light of light sources of three colors of RGB may be emitted in a manner similar to the first light emission and the light emission for reading, but light of one color (for example, green) of RGB may be only emitted. The second light emission will be described below in detail. 
     The light emission for reading is performed with respect to an image of the document P statically placed on the document placement portion  7  with the record surface set downward while the light emitting unit  41  respectively switches the light sources of RGB at high speed. While this light emission for reading is performed, the image reading unit  4  moves in the Y-axis direction and reads the reflected light by the light receiving unit  42  and thereby, image data is created. 
     The first light emission is performed in order to acquire correction data (white reference data) for white color. As shown in  FIG. 3 , a white reference tape  12  (an example of a white colored portion) disposed as a complete white reference is stuck long along the X-axis direction on a back surface  10   b  which is a surface opposed to the glass plate  5  of the positioning member  10 . The white colored portion is not limited to the white reference tape  12  and other configurations such as a paint may be adopted. Then, before reading an image, the image reading unit  4  stops in the white reference position  21  corresponding to the white reference tape  12  and performs light emission (this light emission is described as the first light emission) for acquiring the white reference data and reads the light reflected from the white reference tape  12  by the light receiving unit  42 . The first light emission is ended after the white reference data is acquired. 
     The image reading unit  4  is set so as to stop in plural positions including the reference position  20 , the white reference position  21  or the mark position  24  described above (see  FIG. 3 ). The image reading unit  4  after searching the reference position  20  moves to a standby position  22  and stands by the next command. 
     In addition, in this embodiment, the reference position  20 , the standby position  22 , the white reference position  21  and the mark position  24  are set in a region of the side of the back surface  10   b  of the positioning member  10 , but these positions are not limited to the sorting order of this embodiment and may be changed properly. For example, the reference position  20  and the standby position  22  may be set in the same position, and the positions vary depending on models of the image reading apparatus. 
     A cover body  9  of the size for covering the whole document placement table  3  is attached to an upper portion of the image reading apparatus  1  freely opened and closed around the back end (upper side of  FIG. 2 ). The opening and closing of the cover body  9  can be detected by an opening and closing sensor (an example of an opening and closing detection unit)  31 . As the opening and closing sensor, a sensor of a pressure type is suitable, but other types such as an optical type may be applied. 
     Also, an operation unit  51  that receives an input, which includes plural keys such as a start key for instructing reading of a document or a power source switch of the image reading apparatus  1 , is arranged in an upper surface or a side surface of the image reading apparatus  1 . In addition, the image reading apparatus  1  may be connected to an external device such as a personal computer and the image reading apparatus  1  via the interfaces  61 ,  62 ,  63  is commanded to operate by a key operation of the external device. 
     A mark portion  11  (an example of a display portion and a first portion of the display portion), which is light-transmissive, is disposed in the positioning member  10  for guiding an arrangement position of the document P. In this embodiment, the mark portion  11  includes a hole extend through a front surface  10   c  and a back surface  10   b  of the positioning member  10  as shown in  FIG. 4A . 
     The mark portion  11  is used for positioning of the X-axis direction of the document P, and end mark portions  11   a  for indicating positions of two sides parallel to the Y-axis direction of the document P are disposed in pairs. Plural pairs of the end mark portions  11   a  are disposed so that plural sizes of documents (for A4, B5, B4, postcard, letter size, etc.) can be aligned with the document placement portion  7 . The end mark portion  11   a  is bored so as to show a rectangular shape elongated in the Y-axis direction when viewed from the plane. 
     Also, a center mark portion  11   b  for indicating a center position of the document P is disposed in the mark portion  11 . The center mark portion  11   b  is bored so as to show a triangular shape directed to the side of the document placement portion  7  when viewed from the plane. 
     Since the mark portion  11  is bored in the positioning member  10  as described above, light of the image reading unit  4  can be transmitted toward the front surface side of the positioning member  10  through the mark portion  11  when the image reading unit  4  stops in the position (mark position  24 ) of the back surface side of the mark portion  11  and emits light. Consequently, a user can see the mark portion  11  as if the mark portion  11  emits light, when viewed from the front surface side. Light emission for illuminating the mark portion  11  performed by the image reading unit  4  in this mark position  24  is described as the second light emission (an example of a first operation). 
     In this embodiment, the CIS is adopted as the image reading unit  4 , so that the light emitting unit  41  includes a light source of LEDs of three colors of R, G and B. Therefore, the second light emission can be set at red color (red), green color (green), blue color (blue) or colors obtained by arbitrarily combining these three colors as well as white color. Also, blinking light emission or light emission while switching different colors can be performed as well as continuous light emission. Therefore, the second light emission can be freely set according to user&#39;s preference when the CIS is adopted as the image reading unit  4 . That is, the settings such as color or pattern (e.g., blinking) of the light during the second light emission is changeable in accordance with the input from the operation unit  51 , and the settings are stored in the flash memory  74 . In addition, when CCD (Charge Coupled Devices) are adopted as the image reading unit  4 , a light source of the light emitting unit  41  is only white, so that color cannot be freely set in the second light emission. 
     The second light emission is used in the case of aligning the document P with the document placement portion  7 , so that the second light emission is ended when closing of the cover body  9  is detected by the opening and closing detection unit. 
     The end mark portions  11   a  and the center mark portion  11   b  disposed as the mark portion  11  are scattered along a longitudinal direction of the positioning member  10  and are used for positioning of the document P, so that the mark portions are normally present within the same dimension as a length of the X-axis direction in a reading region of the document. In other words, all the mark portions  11  are present within the same length dimension as a length of the X-axis direction of the image reading unit  4 . Therefore, when the image reading unit  4  emits light in the mark position  24 , all the mark portions  11  can be illuminated simultaneously. That is, it is unnecessary to dispose a light source every mark portion  11 , and light of the image reading unit  4  which is a common light source is only emitted. 
     Also, in order to clearly indicate a correspondence of each of mark portions  11   a  and each of positions of document sizes, shapes of characters such as “A4” or “postcard” may be bored in the positioning member  10  and illuminated. Of course, these characters may be only printed or inscribed on the front surface  10   c  of the positioning member  10 . 
     In addition to the mark portion  11  simply including the hole shown in  FIG. 4A , as shown in  FIG. 4B , the mark portion  11  may include a transmissive member  14  (light transmissive material such as resin material) buried in a through portion  13  formed by a hole formed in the positioning member  10 . Also, as shown in  FIGS. 4C and 4D , a recessed portion  15  may be formed in the position of the mark portion  11  in the positioning member  10  from the side of the back surface  10   b  ( FIG. 4C ), or a plate thickness may be thinned by forming a recessed portion  16  from the side of the front surface  10   c  ( FIG. 4D ). The configuration of  FIG. 4B  or  FIG. 4C  has an advantage capable of preventing a foreign substance such as wastes from entering the mark portion  11 . In addition, the mark portion  11  may be formed as a notch formed in the positioning member  10  at a region contiguous to the document placement portion  7 . 
     An operation of the image reading apparatus  1  will be described using a flowchart of  FIG. 5 . When a power source of the image reading apparatus  1  is turned on, the light emitting unit  41  of the image reading unit  4  emits light (S 101 ), then the reference position  20  is searched (S 102 ) and then the light is turned off (S 103 ). Then, the image reading unit  4  moves to the standby position  22  in a state of turning off the light and wait a command of an operation at the standby position (S 104 ). 
     When the cover body  9  is opened by a user and this opening operation is detected by the opening and closing detection unit (Yes in S 105 ), the image reading unit  4  moves to the white reference position  21  by assuming that it is an operation in which the user attempts to read an image from now on (S 106 ). In the white reference position  21 , the image reading unit  4  performs the first light emission and acquires white reference data (S 107 ). The first light emission is ended after the data is acquired (S 108 ). 
     After the white reference data is acquired, the image reading unit  4  moves to the mark position  24  in a state of turning off the light (S 109 ) and then performs the second light emission (S 110 ). Consequently, the end mark portions  11   a  and the center mark portion  11   b  disposed in the positioning member  10  are simultaneously illuminated. As a result of that, the user can easily grasp a proper placement position of the document P regardless of the surrounding luminance at a time of placing the document P on the document placement portion  7 . 
     When the placement of the document P on the document placement portion  7  is completed and the opening and closing detection unit detects the close of the cover body  9  (Yes in S 111 ), the image reading unit  4  ends the second light emission (S 112 ) and moves to a reading start position  23  in a state of turning off the light (S 113 ). Then, when a start key of image reading is depressed (Yes in S 114 ), the image reading unit  4  performs the light emission for reading (S 115 ) and starts reading of the document (S 116 ). The image reading unit  4  moves along the Y-axis direction and to the end of a reading region and ends reading (S 117 ). After reading is ended, the reference position  20  is again searched in a state of emitting light (S 102 ) and the reference position  20  is reset. By resetting the reference position  20  after reading thus, the reference position  20  is prevented from deviating. 
     The document may be read in a state where the cover body  9  is not closed after the document is set on the document placement portion  7  by being guided to the mark portion  11  that is shining brightly. That is, when the start key is depressed (Yes in S 118 ) without closing the cover body  9  (No in S 111 ), the image reading unit  4  moves to the reading start position  23  in a state of opening the cover body (S 119 ), performs the light emission for reading (S 115 ) and reads the document (S 116 ) in a manner similar to the above. 
     Also, there are cases where the start key is not depressed for a long time (No in S 114 ) even when the document. P is placed on the document placement portion  7  and the cover body  9  is closed (Yes in S 111 ). For example, there are cases where the document P is set on the document placement portion  7  and a user leaves its place in a state of closing the cover body and the document P is left. In such cases, when a preset predetermined time T has elapsed (Yes in S 120 ), the image reading unit  4  emits light of the light emitting unit  41  (S 121 ) and searches the reference position  20  (S 102 ) and turns off the light (S 103 ) and then moves to the standby position  22  and stands by (S 104 ). 
     Also, there are cases where the start key is depressed (Yes in S 122 ) without opening the cover body  9  (No in S 105 ) regardless of the presence or absence of setting of the document. For example, there are cases where a user returns and presses the start key after the image reading unit  4  moves to the standby position  22  because a long time (predetermined time T or longer) has elapsed in a state of setting the document as described above. In such cases, in order to newly acquire white reference data, the image reading unit  4  moves to the white reference position  21  (S 123 ) and performs the first light emission and acquires the white reference data (S 124 ) and ends the first light emission (S 125 ). Then, the image reading unit  4  moves to the reading start position  23  (S 126 ) and performs the light emission for reading (S 115 ) and reads the document (S 116 ) in a manner similar to the above. 
     Thus, according to the embodiment, the mark portion  11  is illuminated when a user sets the document P on the document placement portion  7 , so that the user can speedily find a proper placement position of the document regardless of the environment of the surrounding luminance. 
     Also, this image reading unit  4  is essentially used for reading of an image, so that it is unnecessary to provide an additional light source separately as the light source of the mark portion  11 , and cost reduction and space saving can be achieved. 
     Also, even when plural (multiple) mark portions  11  are disposed in the positioning member  10 , the image reading unit  4  has about the same dimension as a dimension of a longitudinal direction where the mark portions are disposed, so that the plural (multiple) mark portions  11  can be simultaneously illuminated by one image reading unit  4 . 
     Further, according to the embodiment, the open of the cover body is detected, then the image reading unit  4  is moved to the mark position  24  and then the mark portion  11  is illuminated. Since the image reading unit  4  is essentially used for reading of an image, the image reading unit  4  does not necessarily stand by in the mark position  24  in a normal state. However, an operation in which a user opens the cover body  9  is recognized as an operation in which the user will set the document P, so that the image reading unit  4  speedily moves to the mark position  24  and the mark portion  11  can be illuminated with appropriate timing when the document is set. 
     In addition, the flowchart shown in  FIG. 5  can be properly changed without departing from the scope of the invention. For example, a series of operations for acquiring white reference data may be executed at timing different from that of the flowchart shown in  FIG. 5 .  FIGS. 6 and 7  show modified examples of the flowchart shown in  FIG. 5 . In addition, the same numerals are assigned to the same operations as those of  FIG. 5  and detailed description is omitted. 
     In a flowchart of  FIG. 6 , after the cover body  9  is opened (Yes in S 105 ), the image reading unit  4  located in the standby position  22  is immediately moved to the mark position  24  (S 209 ) and the second light emission is performed toward the mark portion  11  (S 210 ) and the mark portion  11  is illuminated. Then, after the cover body  9  is closed (Yes in S 111 ) and the second light emission is ended (S 112 ), the image reading unit  4  is moved to the white reference position  21  (S 206 ) and the first light emission is performed and the white reference data is acquired (S 207 ) and then the first light emission is ended (S 208 ). 
     Consequently, as compared with the flowchart shown in  FIG. 5 , time taken to illuminate the mark portion  11  after the cover body  9  is opened can be reduced and convenience of a user is improved. 
     A flowchart of  FIG. 7  further modifies the flowchart of  FIG. 6 , and according to the process shown in  FIG. 7 , the white reference data is created after a start key is pressed. That is, when the start key is depressed (Yes in S 114  or Yes in S 118  or Yes in S 122 ), the image reading unit  4  is moved to the white reference position  21  (S 306 ) and the first light emission is performed, the white reference data is acquired (S 307 ) and then the first light emission is ended (S 308 ). Thereafter, the image reading unit  4  immediately moves to the reading start position  23  (S 313 ) and an image is read. 
     In this case, the white reference data can be acquired in a state of closing the cover body  9  except when the start key is depressed in a state of opening the cover body  9  (Yes in S 118 ). Therefore, influence of outside light is not suffered at the time of acquiring the white reference data, which leads to an advantage capable of acquiring the white reference data with high accuracy. 
     In addition, in the flowcharts of  FIGS. 5 to 7 , the case where the CIS which is the image reading unit  4  is turned off except for the durations of the light emission for searching the reference position  20 , the first light emission, the second light emission and the light emission for reading has been described. However, when a power source of the image reading apparatus  1  is turned on, the CIS may always emit light and be switched to light emission for searching the reference position, the first light emission, the second light emission and the light emission for reading according to situations. When the image reading unit  4  includes a CCD, it is desirable to always emit light from the standpoint of power consumption or durability (life) of the CCD. 
     Also, the invention may be applied to an embodiment in which an ADF (automatic paper feeder) is added to an image reading apparatus of a flat bed type, as well as the embodiment of the image reading apparatus  1  of the flat bed type as shown in the drawings. 
     In the above embodiments, the positioning member  10  is exemplified as the second portion of the display portion, and the mark portion  11  of which has higher transmittance than the positioning member  10  is exemplified as the first portion of the first portion. However, the display portion may include any configuration transmissive of the light emitted from the light emitting unit  41  of the image reading unit  4  that is movable along the first direction (sub-scanning direction) and is positioned at the position corresponding to the display portion. 
     In addition, the positioning member  10  may have higher transmittance than the mark portion  11 . For example, the positioning member  10  (frame body  6 ) may be formed of a transmissive member, and the mark portion  11  may be printed on the frame body  6 . 
     The first and second portions (e.g., the positioning member  10  and the mark portion  11 ) of the display portion have different transmittance. However, the first and second portions may have different light transmission characteristics such as different transmittances or different transmissive wavelengths. 
     In the above embodiments, the mark portion  11  and the positioning member  10  is exemplified as the first and second portions, respectively. However, the display portion may be other configurations. For example, the display portion may be realized by any combination of the first and second portions having different light transmission characteristics, and the first portion may be text, pattern, figure etc. Also, the display portion may include a display device such as LCD using the light from the light emitting unit  41  as a backlight. 
     According to the embodiment of the invention, the image reading unit having the light emitting unit for emitting light to the document is disposed movably along a back surface of the document placement portion and a back surface of a positioning member and also, a light-transmissive mark portion of the positioning member is disposed. Consequently, when the image reading unit is positioned to the back surface side of the mark portion and emits light, its light is transmitted toward the front surface side of the positioning member through the mark portion, and the mark portion looks bright to a user who attempts to place a document on the document placement portion. Therefore, even when environment of the periphery is bright or dark, the mark portion is easy to recognize and the user can easily arrange a document in a proper position of the document placement portion. 
     Also, the image reading unit essentially used for reading of a document is utilized as a light source for illuminating the mark portion. That is, an additional light source for the mark portion is not added, so that an increase in cost can be avoided and it is also unnecessary to separately dispose arrangement space of a light source for addition. 
     Further, when the opening and closing detection unit detects opening of a cover body, the control unit moves the image reading unit to the back surface side of a mark portion and makes the image reading unit emit light for the mark portion. Since an image reading apparatus is disposed for reading of a document, the image reading apparatus is not always positioned to the back surface side of the mark portion. As a result of that, it is decided that opening of the cover body is an operation in which a user will place a document on a document placement portion, and the image reading unit is speedily moved to the back surface side of the mark portion, so that the mark portion can be illuminated with good timing when the user places the document. 
     Furthermore, since it can be decided that an operation in which the user closes the cover body indicates the end of placement of the document on a document placement portion by the user, light emission for a mark portion of the image reading unit is stopped when the opening and closing detection unit detects closing of the cover body. Consequently, the light emission for the mark portion is prevented from being performed more than necessary. 
     Still further, the positioning member is formed along the first side of a document placement portion, and a plurality of mark portions are disposed along a longitudinal direction of this positioning member. That is, the plural mark portions are disposed along the longitudinal direction of the positioning member and the image reading unit has substantially the same length as that of the first side, so that the plural mark portions disposed in the positioning member can be simultaneously illuminated by one image reading unit. 
     Furthermore, since blinking or change in color of light emission for a mark portion can be set, the setting can be made according to user&#39;s preference. For example, when the CIS (Contact Image Sensor) is adopted the image reading unit, the light emitting unit includes an LED light source of R (red), G (green) and B (blue), so that light emission color or light emission time can be adjusted easily. 
     When the mark portion is formed so as to extend through front and back surfaces of a positioning member, it has advantages of having high transmittance in addition to easy processing. 
     When the mark portion is formed by burying the transmissive member in the hole formed so as to extend through front and back surfaces of a positioning member, it has advantages that wastes etc. are resistant to entering the hole though transmittance is lower than the mark portion with only the hole. 
     When the mark portion is formed by thinning a plate thickness of a positioning member, it has advantages that wastes etc. are resistant to entering a through portion though transmittance is lower than the mark portion with only the hole.