Image reader and method of producing thereof

An image reader has an image sensor; a carriage; a positioning portion formed at a predetermined position in a longitudinal direction of the image sensor with respect to a reference position of the image sensor; a connector portion to which an electric cable is connected and which is provided between an end of the carriage and one end in the longitudinal direction of a case of the image sensor; and an engaging portion formed in the carriage. In the image recording apparatus, since the positioning portion is engaged with the engaging portion, it is possible to use a common carriage for a plurality of types of image sensors, and an operation of connecting the electric cable becomes simple.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent Application No. 2005-191545, filed on Jun. 30, 2005, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image reader in which an image sensor, which irradiates light on a recording-objective medium (reading-objective medium), photoelectrically converts reflected light from the recording-objective medium and outputs the reflected light to a control unit, is mounted on a carriage, and the carriage is reciprocated by a scanning mechanism in parallel to a surface for placing a recording-objective medium, and to a method of producing the image reader.

2. Description Of The Related Art

As disclosed in U.S. Pat. No. 6,903,849 (corresponding to Japanese Patent Application Laid-open No. 2001-346006) for example, a so-called flat bed scanner, in which an image sensor such as CCD (Charge Coupled Device) or CIS (Contact Image Sensor) provided inside a placing-reading table is mounted on a carriage for reading an image of an original by scanning, is known as an image reader mounted in a copying machine or a multifunction machine.

FIG. 13is a diagram showing a conventional image sensor and a carriage. As shown in the diagram, an image sensor90has a rectangular parallelepiped shape with a longitudinal direction being primary scanning direction (main scanning direction). The image sensor90has an upper surface91, which is a surface for reading an image or a letter. The image sensor90is a so-called CIS, in which light is irradiated from a light source provided inside the image sensor90to the outside via the upper surface91, and reflected light from a medium to be read (recording-objective medium) incidents on the image sensor90via the upper surface91. The incident reflected light is collected to a photoelectric conversion element by a lens, thereby outputting an electric signal corresponding to the intensity of the reflected light.

The carriage92is for holding the image sensor90. As shown in the diagram, the carriage92is a container having an open upper side and capable of enclosing the image sensor90. The image sensor90is accommodated in the carriage92to be enclosed therein, and is positioned in a primary scanning direction and a secondary scanning direction by engagement structures having projection and recess shapes for example, which are formed appropriately on the image sensor90and the carriage92.

The carriage92is arranged to be reciprocapable along a guide shaft of a scanning mechanism by engaging with the guide shaft. Further, the carriage92is coupled to a timing belt of the scanning mechanism and reciprocates by receiving drive transmission via the timing belt. An engaging portion with the guide shaft and a coupling portion to the timing belt are formed on a bottom surface of the carriage92. Further, to the image sensor90, an electric cable for outputting an electrical signal and supplying power to the light source and so forth is connected. A connector portion to be connected to the electric cable is provided on a bottom surface of the image sensor90. The electric cable connected to the connector portion is drawn inside a space between the image sensor90and the carriage92and extended from a predetermined position on the carriage92to the outside of the carriage92.

The image sensor90performs reading of an image of a recording-objective medium with its longitudinal direction being the primary scanning direction and a direction orthogonal to the primary scanning direction being the secondary scanning direction. Therefore, the length in the longitudinal direction of the image sensor90corresponds to the width of a recording-objective medium of the maximum readable size, and inside the image sensor90, a light source and a photoelectric conversion element which correspond to the width of the recording-objective medium of the maximum size are provided. Therefore, depending on whether the recording-objective medium of the maximum readable size is A4 size or A3 size for example, the length in the longitudinal direction of the image sensor90is different. As a matter of course, the image sensor90capable of reading a recording-objective medium of the A3 size can read an image of a recording-objective medium of the A4 size, but naturally, the costs thereof increase as the length of the image sensor90becomes long. Therefore, using the image sensor90corresponding to, for example, the A3 size for all image readers without considering the frequency of usage, users' needs and the like is not appropriate in view of the costs and the size of the apparatus. In short, it is preferable to produce image readers capable of reading up to the A3 size and image readers capable of reading up to the A4 size for example according to respective demands for them.

As the carriage92accommodating the image sensor90, a carriage corresponding to the length of the image sensor90is designed. Specifically, dedicated carriages92according respectively to lengths of the image sensor90corresponding to the A3 size and the image sensor90corresponding to the A4 size have been used.

Further, to the connector portion provided on the bottom surface of the image sensor90, the electric cable cannot be connected in a state that the image sensor90is accommodated in the carriage92. Therefore, there is adopted a working method such that after the electric cable is drawn inside the carriage92in advance and immediately before the image sensor90is engaged with the carriage92, the electric cable is connected to the connector portion. For example, the image sensor90and the carriage92are engaged pivotally by a shaft and a bearing, and in this engaging state, after the electric cable is connected to the connector portion, the image sensor90is pivoted about the carriage92so as to accommodate the image sensor90in the carriage92. In this manner, an operation of keeping the image sensor90and the carriage92in a predetermined engaging state and further connecting the electric cable is difficult, which often causes a problem that a worker comes in contact with the upper surface91of the image sensor90. The upper surface91is an optical path for reading an image of a recording-objective medium, and hence there is a problem if scratching, fogging or the like due to the contact by a worker occurs, a read image by the image sensor90deteriorates.

SUMMARY OF THE INVENTION

The present invention is made in view of such problems, and an object thereof is to provide an image reader in which an image sensor is mounted on a carriage and the carriage is reciprocated by a scanning mechanism in parallel to a surface for placing recording-objective medium, and which realizes cost decrease for the carriage and simplifies connection of an electric cable to the image sensor, and to provide a method of producing the same.

According to a first aspect of the present invention, there is provided an image reader, including: an image sensor having an elongated shape; a carriage; a positioning portion formed at a predetermined position in a longitudinal direction of the image sensor with respect to a reference position in a case of the image sensor; a connector portion to which an electric cable is connected and which is provided between an end of the carriage and one end in the longitudinal direction of the image sensor; and an engaging portion formed in the carriage; wherein the positioning portion is engaged with the engaging portion.

In the image sensor according to the present invention, a recording-objective medium of the maximum readable size is determined such as A4 size and A3 size for example. For example, in order for a contact-type image sensor such as a CIS to read an image of a recording-objective medium of a predetermined size, the length in the longitudinal direction of the case of the image sensor is not less than the width of the recording-objective medium. Therefore, an image sensor for which the recording-objective medium of the maximum readable size is the A4 size has a case with a length corresponding to the A4 size, and an image sensor for which the recording-objective medium of the maximum readable size is the A3 size has a case with a length corresponding to the A3 size. Then, the image sensor is moved relative to the recording-objective medium with the longitudinal direction of the case being a primary scanning direction so as to perform reading of an image.

In the image sensor, a positioning portion for positioning the image sensor with respect to the carriage is formed. This positioning portion is formed at a predetermined position with respect to the reference position in the longitudinal direction of the case of the image sensor. In other words, for example, either when the recording-objective medium of the maximum readable size is the A4 size or when it is the A3 size, the positioning portion is at the predetermined position with respect to the reference position in the longitudinal direction of the case of the image sensor. Further in other words, the positioning portion is at a common position for plural types of image sensors which are different in the recording-objective medium of the maximum readable size.

In the image sensor, the connector portion to which an electric cable is connected is provided. The connector portion is arranged between the one end in the longitudinal direction of the image sensor and the end of the carriage. Therefore, attaching of an electric cable or the like to the connector portion becomes simple. The electric cable is, for example, for outputting output signals to a control unit from the image sensor and inputting control signals from the control unit to the image sensor.

In the carriage, the engaging portion for engaging with the positioning portion of the image sensor is formed. Since the positioning portion of the image sensor is at the common position for plural types of image sensors, the engaging portion is formed at a constant position regardless of the type of the image sensor mounted on the carriage, namely the length in the longitudinal direction of the case. Accordingly, the carriage is made common for the plural types of image sensors. By this commonizing of the carriage, it is possible to decrease the costs of the apparatus.

In the image reader according to the present invention, the image sensor may be mounted on the carriage such that the one end to which the connector portion is provided is projected to outside of the carriage. In this manner, when connecting the electric cable to the connector portion, there is no need to remove the image sensor from the carriage. Accordingly, an operation of connecting the electric cable becomes simple, and a possibility of a contact with the upper surface of the image sensor while working is decreased. Further, the carriage is reduced in size, so that the costs of the carriage can be decreased.

In the image reader according to the present invention, the connector portion may be provided in a bottom surface of the image sensor. In this manner, although the bottom surface of the image sensor mounted on the carriage is covered by the carriage, one end of the image sensor is projected from the carriage. Accordingly, the electric cable can be connected to the connector portion in a state that the image sensor is mounted on the carriage.

In the image reader according to the present invention, the image sensor may have a cable holder which holds the electric cable at a predetermined position separated from the connector portion. In this manner, regardless of the position of the connector portion, a position in the primary scanning direction, at which the electric cable is extended from the image sensor, can be set at a desired position.

In the image reader according to the present invention, the cable holder may restrain movement of the electric cable in a longitudinal direction of the electric cable. In this manner, between the connector portion and the cable holder, load in the electric cable can be constant. Further, by loosing the electric cable between the connector portion and the cable holder, no load is transmitted via the electric cable to a connecting position at which the connector portion and the electric cable are connected. Accordingly, even when the electric cable changes in posture along with the reciprocating movement of the carriage, any excessive load will not be generated at the connecting position of the connector portion and the electric cable.

In the image reader according to the present invention, the reference position may be a center in the longitudinal direction of the image sensor. In this case, the reference position can be determined easily.

In the image reader according to the present invention, the positioning portion may include first and second positioning portions, and the first positioning portion may engage with the carriage in an inner surface of the carriage and the second positioning portion may engage with the carriage in an outer surface of the carriage. In this manner, the image sensor can be mounted in the carriage easily.

In the image reader according to the present invention, the engaging portion may include first and second engaging portions, and the first engaging portion may be formed in an inner surface of the carriage and the second engaging portion may be formed in an outer surface of the carriage. In this manner, the image sensor can be mounted easily in the carriage.

According to a second aspect of the present invention, there is provided an image reader, including: an image sensor; a carriage used in common for the image sensor and another image sensor having a size different from that of the image sensor; and an engaging portion which is provided to the image sensor to engage with the carriage, and which is provided at a position same for the image sensor and the another image sensor.

In the present invention, the engaging portion of the image sensor is provided at the position same for the positioning portion of the image sensor and another image sensor having a size different from that of the image sensor, so that each of the image sensor and the another image sensor can be mounted in the common carriage even when the size thereof are different.

In the image reader according to the present invention, the image sensor and the another image sensor having the size different from that of the image sensor may have a common reference position, and the position of the engaging portion may be determined with respect to the reference position. In this manner, the engaging portion can be determined at the same position with respect to the image sensors having different sizes.

In the image reader according to the present invention, the reference position may be a center in a longitudinal direction of the image sensor, and the position of the engaging portion may be a position separated from the reference position by a predetermined distance in the longitudinal direction of the image sensor. In this manner, the reference position and the position of the engaging portion can be determined easily.

In the image reader according to the present invention, a connector portion to which an electric cable is connected may be provided between an end of the carriage and one end in a longitudinal direction of each of the image sensor and the another image sensor having the size different from that of the image sensor. In this manner, the one end of the image sensor is projected from the carriage, so that the electric cable can be connected to the connector portion in a state that the image sensor is mounted on the carriage.

In the image reader according to the present invention, a portion to be engaged (engage-objective portion) which is engaged with the engaging portion may be formed in the carriage.

In the image reader according to the present invention, the engaging portion may include first and second engaging portions, and the first engaging portion may engage with the carriage on an inner surface of the carriage and the second engaging portion may engage with the carriage in an outer surface of the carriage.

In the image reader according to the present invention, the engage-objective portion may include first and second engage-objective portions, and the first engage-objective portion may be formed in an inner surface of the carriage and the second engage-objective portion may be formed in an outer surface of the carriage.

According to a third aspect of the present invention, there is provided a method of producing an image reader, including: providing image sensors which have an elongated shape, which have various lengths, and each of which has an engaging portion formed at a position common for the image sensors having various lengths; providing a carriage which is used in common for the image sensors having various lengths, and which has an engage-objective portion to be engaged with the engaging portion; engaging the engaging portion of one of the image sensors with the engage-objective portion of the carriage so as to mount one of the image sensors in the carriage; and assembling, to a body of the image reader, one of the image sensors mounted in the carriage and other parts.

In the present invention, the engaging portion of each of the image sensors of the various lengths is formed at the position common for the image sensors of various lengths, so that image sensors of various sizes can be mounted in a common carriage having the engaging portion at a corresponding position.

In the method of producing the image reader according to the present invention, a connector may be attached to one of the image sensors such that the connector exists at a position outside the carriage when one of the image sensors is mounted in the carriage. In this case, an operation of attaching the electric cable or the like to the connector becomes easy.

In the method of producing the image reader according to the present invention, the connector may be attached after one of the image sensors has been mounted in the carriage. In this case, the connector can be attached to the image sensor without inattentively touching the image sensor.

In the method of producing the image reader according to the present invention, the connector may be attached before one of the image sensors is mounted in the carriage. In this case, an operation of attaching the connector to the image sensor becomes easy.

PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION

First Embodiment

FIG. 1is a diagram showing an exterior structure of an image reader1according to a first embodiment of the present invention. This image reader1is used as, for example, a scanner section of a Multi-Function Device (MFD) which has a printer function and a scanner function integrally, or used as an image reading section of a copy machine, but the printing function or the like is an optional mechanism in the present invention, and thus the image reader1may be realized, for example, as a flatbed scanner (FBS) having only the scanner function.

As shown in the diagram, the image reader1is constructed such that an original (original document of manuscript) holding cover4having an auto document feeder (ADF)3is attached in an openable/closable manner to a placing-reading table2which functions as the FBS. The placing-reading table2is constructed such that a platen glass21is disposed on a ceiling surface of a case20having a substantially rectangular parallelepiped shape, and an image reading unit5is provided inside the case20. The upper surface of the platen glass21is a surface for placing recording-objective medium thereon. Therefore, when the image reader1is used as the FBS, an original as a medium to be read (recording-objective medium) is placed on the platen glass21, an original holding cover4is closed to secure the original, and an image of the document is read by scanning with the image reading unit5.

Further, on a front side of the placing-reading table2, an operation panel22is provided. The operation panel22is constructed of various types of operation buttons and a liquid crystal display section, and the image reader1operates by instructions given via the operation panel22. In addition, when the image reader1is realized as the MFD, the image reader1is connected to a computer and operates also by, besides the instruction from the operation panel22, instructions transmitted from the computer via a scanner driver or the like.

On the original holding cover4, an ADF3which continuously carries originals from an original tray to a paper discharge tray is provided. An original passes through a platen23in a carrying process by the ADF3, and the image reading unit5reads an image of the original at a position below the platen23. Note that the ADF3has an optional construction in the present invention.

The case20of the placing-reading table2is constructed of a lower frame20A which has a container form and which is open in an upper surface thereof, and an upper cover20B having an opening formed in the center thereof for exposing the platen glass21. As shown inFIG. 2, the image reading unit5is arranged inside the lower frame20A. The lower frame20A and the upper cover20B are both made of synthetic resin, and the lower frame20A is formed integrally of a base portion24forming a bottom plate, side walls25standing from the periphery of the base portion24, and a partition plate26for partitioning a portion at which the image reading unit5is arranged and a portion at which a substrate for the operation panel22or the like are arranged. Note that in the lower frame20A, a support rib for supporting the platen glass21, a boss portion for screwing various types of members, a through hole for an electrical wiring or the like, and so forth are provided further, but since they are designed appropriately depending on an embodiment of the placing-reading table2, detailed descriptions of which are omitted.

As shown inFIG. 2, the image reading unit5is constructed of an image sensor50, a carriage51, a guide shaft52, and a belt drive mechanism53. The image sensor50is a contact-type image sensor which irradiates light on an original as a recording-objective medium, photoelectrically converts reflected light from the original, and outputs an electrical signal, and is generally referred to as CIS. The image sensor50has a case49mounted on the carriage51, and performs scanning under the platen glass21with a longitudinal direction of the case49being a primary scanning direction and a short side direction thereof being a secondary scanning direction. The carriage51engages with the guide shaft52provided in a width direction of the lower frame20A, and is driven by the belt drive mechanism53to slide and move on the guide shaft52. By the carriage51mounting the image sensor50in close contact with the platen glass21and moving on the guide shaft52, the image sensor50is reciprocated in parallel to the platen glass21.

As shown inFIG. 3, the carriage51mounts, on its upper side, the image sensor50in a manner to support the image sensor50thereon, and on a lower surface of the carriage51, there is formed a shaft receiving portion54which engages with the guide shaft52in a manner to straddle thereon from above. The shaft receiving portion54and the guide shaft52engage with each other, and the carriage51is supported by the guide shaft52to be slidable in an axial direction of the guide shaft52. Further, beside the shaft receiving portion54, a belt holding portion55is provided to project downward. The belt holding portion55holds a timing belt61of the belt drive mechanism53, which will be described later, to couple the timing belt61to the carriage51. Accordingly, drive force is transmitted from the belt drive mechanism53to the carriage51, and thereby the carriage51moves on the guide shaft52.

Further, inside the carriage51in which the image sensor50is mounted, spring receiving portions56are formed at two positions, namely left and right positions respectively. Coil springs57are positioned by the spring receiving portions56and interposed between the image sensor50and the carriage51. By these coil springs57, the image sensor50mounted on the carriage51closely contacts a lower surface of the platen glass21in a pressing manner thereto. Rollers58are provided on both ends of the image sensor50, respectively, and by the rollers58, the image sensor50, pressed to the lower surface of the platen glass21, smoothly moves along with movement of the carriage51while closely contacting the lower surface of the platen glass21.

The belt drive mechanism53is constructed such that, as shown inFIG. 4, the timing belt61which is an endless belt having tooth formed inside thereof is wound and laid between a drive pulley59and a driven pulley60, rotation of a motor is outputted to the shaft of the drive pulley59, and rotation of the drive pulley59enables peripheral movement of the timing belt61. As shown in the diagram, the drive pulley59is disposed at a far left position in the lower frame20A, and the timing belt61wound around the drive pulley59extends to the front surface side of the lower frame20A and is wound around intermediate pulleys62disposed in front of the guide shaft52to turn substantially perpendicularly, and extends to a right end of the lower frame20A along the guide shaft52and is wound around the driven pulley60disposed in the vicinity of the right end, thereby being arranged in an L-shape. A portion between the driven pulley60and the intermediate pulleys62of the timing belt61arranged in this manner, namely a portion along the guide shaft52, is held by the belt holding portion55of the carriage51and thereby the timing belt61is coupled to the carriage51. Note that for the timing belt61, it is needless to mention that, other than the endless belt, it is possible to use a belt with ends, the both ends of which being fixed to the carriage51.

Hereinafter, structures of the image sensor50and the carriage51will be described in detail.

As shown inFIG. 5, the image sensor50has the case49in a rectangular parallelepiped shape with an upper surface63thereof being a slender rectangle in a plan view. On the upper surface63of the case49, a light guide64for guiding a light of an LED provided inside the case49is arranged in a longitudinal direction of the case49. By this light guide64, the light of the LED is projected to a side of the upper surface63of the case49of the image sensor50. Further, on the upper surface63of the case49, a lens array65constructed of a plurality of condenser lenses is aligned in a row in the longitudinal direction of the case49in parallel to the light guide64. Further, inside the case49, a plurality of photoelectric conversion elements are aligned in the same direction as the condenser lens array65immediately under or below the condenser lens array65. The light projected from the LED is irradiated on a recording-objective medium, and reflected light therefrom is collected to the photoelectric conversion elements by the condenser lens array65. The light conversion elements output electrical signals according to the intensity of the reflected light. In this manner, the image sensor50outputs an image of the recording-objective medium as electrical signals.

The longitudinal direction of the case49of the image sensor50is the primary scanning direction for reading an image. The length in this primary scanning direction, namely the length in the longitudinal direction of the case49of the image sensor50, is the length corresponding to a recording-objective medium of the maximum size readable by the image sensor50. The image sensor50has a length corresponding to a recording-objective medium of A4 size.

On the case49of the image sensor50, positioning portions66are provided. The positioning portions66are for positioning of the image sensor50with respect to the carriage51in the secondary scanning direction, namely a direction orthogonal to the primary scanning direction. To describe in detail, the positioning portions66are formed such that base portions67are provided to project from ends on one of sides in the short side direction of the case49of the image sensor50, and shafts68are provided to project in the longitudinal direction from the base portions67, respectively. These shafts68engage with shaft receiving portions73, which will be described later, of the carriage51, and thus the image sensor50is positioned in the secondary scanning direction.

The positioning portions66are provided at two positions on one end in the short side direction of the case49of the image sensor50. This pair of the positioning portions66are arranged at predetermined positions with respect to a reference position C in the longitudinal direction of the case49, regardless of the length in the longitudinal direction of the case49of the image sensor50. In other words, in either case of the image sensor50corresponding to the A4 size or a later-described image sensor78corresponding to A3 size, the positioning portions66are arranged at the same positions with respect to the reference position C in the longitudinal direction of the case49. This reference position C is at the center in the longitudinal direction of the case49. As shown in the diagram, the positioning portions66are arranged in the vicinities of both ends in the longitudinal direction of the case49respectively, where a distance L1separated in the longitudinal direction from the reference position C for the positioning portions66is constant regardless of the length in the longitudinal direction of the case49. Note that although in this embodiment the respective distances L1from the reference position C for the respective positioning portions66are equal, the respective distances L1for the pair of the positioning portions66need not be equal as long as the distances from the reference position C are constant.

Further, on the other side in the short direction of the case49of the image sensor50, a projecting portion69(positioning portion) is formed. This projecting portion69is for positioning of the image sensor50in the primary scanning direction by engaging with a recess76, which will be described later, of the carriage51. This projecting portion69is arranged also at a predetermined position with respect to the reference position C in the longitudinal direction of the case49, namely a position separated by a distance L2in the longitudinal direction of the case49from the reference position C, regardless of the length in the longitudinal direction of the case49of the image sensor50.

Further, a connector portion70is provided on a bottom surface of the case49of the image sensor50on one end on a side in the longitudinal direction of the case49. The connector portion70is connected electrically to the LED and the photoelectric conversion elements of the image sensor50for performing inputting/outputting of a signal and the like with a control unit. An electric cable77is connected to the connector portion70, and by the electric cable77, the image sensor50and the control unit of the image reader1are connected electrically. The control unit of the image reader1has, for example, a CPU for performing various arithmetic operations, a ROM storing various types of control programs, a RAM for temporarily storing data, and an ASIC for driving a drive circuit, various interfaces or the like, and so forth. By the electric cable77, an electric signal path is formed between the image sensor50and the control unit.

As shown inFIG. 6, the carriage51is in a container form for mounting the image sensor50thereon. The carriage51has a bottom portion71and walls72provided to stand upward from both sides in secondary scanning direction of the bottom portion71. As shown inFIG. 7, in a space formed by the bottom portion71and the walls72, the image sensor50is accommodated. No wall is provided on both sides in the primary scanning direction of the bottom portion71, and one end of the case49of the image sensor50projects from a side in the longitudinal direction of the carriage51.

As shown inFIG. 6, in one of the walls72, the shaft receiving portions73(engaging portion) for engaging with the positioning portions66are formed. Each of the shaft receiving portions73is formed such that a long hole75in a vertical direction is bored in a projecting piece74provided on the wall72to project upward. As shown inFIG. 7, by inserting the shafts68of the positioning portions66through the long holes75, the positioning portions66and the shaft receiving portions73are engaged. The shaft receiving portions73are arranged at positions corresponding to the pair of the positioning portions66. Therefore, the distance in the longitudinal direction between the pair of the shaft receiving portions73corresponds to the distance in the longitudinal direction of the case49between the pair of positioning portions66, namely approximately the double of the distance L1.

As shown inFIG. 6, in the other one of the walls72, the recess76(engaging portion) is formed corresponding to the projecting portion69. As shown inFIG. 7, by engaging this recess76with the projecting portion69of the image sensor50, the image sensor50is positioned in the primary scanning direction with respect to the carriage51.

It should be noted that although in this embodiment the positioning in the secondary scanning direction is made by the positioning portions66provided on the case49of the image sensor50and the positioning in the primary scanning direction is made by the projecting portion69, the positioning of the image sensor50with respect to the carriage51by the positioning portions66and the projection portion69is an example, and hence their shapes, positioning directions and so forth may be changed.

As shown inFIG. 8, the one end in the longitudinal direction of the case49of the image sensor50accommodated in the carriage51projects from the carriage51. The connector portion70is arranged between the one end of the case49projecting from the carriage51and an end of the carriage51. In other words, the carriage51mounts the image sensor50such that the one end of the case49on which the connector portion70is provided is projected to the outside of the carriage51.

As shown in the diagram, the electric cable77is connected to the connector portion70. The electric cable77is a so-called flat cable in which a plurality of lead wires such as lead wires for supplying power to the LED of the image sensor50and lead wires for outputting electrical signals from the photoelectric conversion elements are arranged in a thin flat form and insulated and coated integrally. The electric cable77is extended in the secondary scanning direction of the image sensor50and the other end thereof is connected to a connector portion provided on an inner surface of the case20of the placing-reading table2, thereby forming an electrical signal path with the control unit connected electrically to the connector portion. Further, the electric cable77is flexible and follows the image sensor50while changing its posture along with the reciprocating movement of the image sensor50.

Next, the structure of the image sensor78will be described in detail.

The image sensor78differs from the image sensor50in the length in the longitudinal direction of a case89. In particular, the image sensor78corresponds to a recording-objective medium larger in size than the image sensor50, such that the image sensor78corresponds to the A3 size whereas the image sensor50corresponds to the A4 size. Further, the image sensor78is mounted also on the carriage51. That is to say, the carriage51is used in common for the image sensors50and78. Note that although in this embodiment the A4 size and the A3 size are shown as the size of an image sensor, the size of an image sensor according to the present invention is not limited thereto, and as a matter of course, image sensors of different sizes may be adapted to be used in common by one carriage.

As shown inFIG. 9, the image sensor78has the case89in a rectangular parallelepiped shape with an upper surface79thereof having a slender rectangular shape in a plan view. It is the same as the image sensor50in that, on the upper surface79of the case89, a light guide80for guiding light from an LED and a lens array81constructed of a plurality of condenser lenses are arranged in the longitudinal direction of the case89. The image sensor78projects the light from the LED via the light guide80and irradiates the light on a recording-objective medium, collects reflected light therefrom with the condenser lens array81to the photoelectric conversion element, and outputs electrical signals according to the intensity of the reflected light. The LED, light guide80, condenser lens array81, and photoelectric conversion elements are provided corresponding to the length in the longitudinal direction of the case89of the image sensor78.

The longitudinal direction of the case89of the image sensor78is the primary scanning direction for reading an image. The length in this primary scanning direction, namely the length in the longitudinal direction of the case89of the image sensor78, is the length corresponding to a recording-objective medium of the maximum size readable by the image sensor78. The image sensor78corresponds to a recording-objective medium of the A3 size, and the image sensor78is capable of reading an image of a recording-objective medium up to the A3 size.

In the image sensor78, positioning portions82are provided. The positioning portions82are for positioning of the image sensor78with respect to the carriage51in the secondary scanning direction, namely a direction orthogonal to the primary scanning direction. The positioning portions82are formed such that base portions83are provided to project from positions each of which is near to an end on one of sides in the short side direction of the case89of the image sensor78, and shafts84are provided to project in the longitudinal direction of the case89from the base portions83. The shafts84are inserted through long holes75of the shaft receiving portions73of the carriage51to engage the positioning portions82with the shaft receiving portions73, and thus the image sensor78is positioned in the secondary scanning direction.

The positioning portions82are provided at two positions on one of sides in the short side direction of the case89of the image sensor78. This pair of the positioning portions82are arranged at predetermined positions with respect to a reference position C in the longitudinal direction of the case89, regardless of the length in the longitudinal direction of the case89of the image sensor78. In other words, the positioning portions82of this image sensor78and the positioning portions66of the image sensor50are arranged at the same positions with respect to the reference position C in the longitudinal direction of the case89. As described above, this reference position C is at the center in the longitudinal direction of the case89. Then, the positioning portions82are arranged respectively at positions separated by the distance L1in the longitudinal direction of the case89from the reference position C of the image senor78.

Further, on the other side in the short direction of the case89of the image sensor78, a projecting portion85(positioning portion) is formed. This projecting portion85is for positioning of the image sensor78in the primary scanning direction by engaging with the recess76of the carriage51. This projecting portion85is arranged also at a predetermined position with respect to the reference position C in the longitudinal direction of the case89, namely a position separated by a distance L2in the longitudinal direction of the case89from the reference position C, regardless of the length in the longitudinal direction of the case89of the image sensor78.

Further, a connector portion86is provided on a bottom surface of the case89of the image sensor78on a side of one end in the longitudinal direction. The connector portion86is connected electrically to the LED and the photoelectric conversion elements of the image sensor78for performing inputting/outputting of a signal or the like with the control unit. The electric cable77is connected to the connector portion86, and forms an electrical signal path with the control unit of the image reader1.

Further, on the end of the image sensor78where the connector portion86is arranged, cable holders87,88are provided. The cable holders87,88are in a hook shape both formed on a side wall of the image sensor78, by which the electric cable77can be locked.

As shown inFIG. 10, the image sensor78is accommodated in a space formed by the bottom portion71and the walls72of the carriage51. No wall is formed on both ends on a side in primary scanning direction of the bottom portion71, and the image sensor78is projected from the sides in the longitudinal direction of the carriage51. Further, the shafts84of the positioning portions82of the image sensor are inserted through the long holes75of the shaft receiving portions73of the carriage51, thereby engaging the positioning portions82with the shaft receiving portions73. As described above, the distance in the longitudinal direction between the pair of the shaft receiving portions73corresponds to approximately the double of the distance L1. Further, since the pair of the positioning portions82is at the positions separated respectively by the distance L1in the longitudinal direction from the reference position C, the positioning portions82and the shaft receiving portions73are at corresponding positions. Further, by engaging the projecting portion85of the image sensor78with the recess76of the carriage51, the image sensor78is positioned in the primary scanning direction with respect to the carriage51.

As shown inFIG. 11, both ends in the longitudinal direction of the case89of the image sensor78accommodated in the carriage51project from the carriage51. The connector portion86is arranged between one end of the case89projecting from the carriage51and an end of the carriage51. In other words, the carriage51mounts the image sensor78such that the one end of the case89of the image sensor78, in which the connector portion86is provided, is projected to the outside of the carriage51.

As shown in the diagram, the electric cable77is connected to the connector portion86. This electric cable77is extended in the secondary scanning direction of the image sensor78and the other end of the electric cable77is connected to the connector portion provided in the inner surface of the case20of the placing-reading table2, thereby forming an electrical signal path with the control unit connected electrically to the connector portion. Further, the electric cable77is flexible and follows the image sensor78while changing its posture along with the reciprocating movement of the image sensor78.

As shown inFIG. 11andFIG. 12, the electric cable77is locked by the cable holders87,88at a predetermined position separated or away from the connector portion86of the image sensor78. By locking with the cable holders87,88, the electric cable77is restrained from moving in a longitudinal direction thereof. Note that although in this embodiment the electric cable77is locked by the two cable holders87,88, a cable holder may be formed at one position. Further, the cable holders are preferably in a hook shape for the simplicity of an operation of locking the electric cable77, but as long as the cable holder is capable of restraining the movement in the longitudinal direction of the electric cable77, the shape of the cable holders are not limited particularly.

As has been described, for the image sensor50corresponding to the A4 size and the image sensor78corresponding to the A3 size, by arranging the positioning portions66,82for positioning in the secondary scanning direction with respect to the carriage51at the positions each separated by the distance L1in the longitudinal direction of the cases49,89from the reference positions C of the image sensors50,78respectively, and by arranging the projecting portions69,85for positioning in the primary scanning direction with respect to the carriage51at the position separated by the distance L2in the longitudinal direction of the cases49,89from the reference positions C respectively, each of the positioning portions66,82and the projecting portions69,85is at predetermined position with respect to the reference positions C in the primary scanning direction of the image sensors50,78either when the recording-objective medium of the maximum readable size is the A4 size or when it is the A3 size. In other words, the positioning portions66,82and the projecting portions69,85are at common positions for the image sensors50,78, respectively.

Further, in the carriage51, the shaft receiving portions73are formed corresponding to the positioning portions66,82, and the recess76is formed corresponding to the projecting portions69,85, so that the carriage51is made common to the image sensors50,78. Thus, by making the carriage51common to the image sensors50,78of a plurality of types which differ in the longitudinal directions of the cases49,89, it is possible to decrease the costs of image readers corresponding to the A4 and the A3 respectively.

Furthermore, regarding the respective image sensors50,78mounted on the carriage51, since the one ends in the longitudinal direction of the cases49,89at which the connector portions70,86are provided, respectively are projected to the outside of the carriage51, the connector portions70,86are located outside the carriage51respectively. Namely, the connector portions70,86are not covered by the carriage51. Accordingly, when connecting the electric cable77to the connector portions70,86, there is no need to remove the image sensors50,78from the carriage51. In other words, in a state that the image sensors50,78are mounted on the carriage51, the electric cable77can be connected to the connector portions70,86. Further, it is possible that after the electric cable77is connected to the connector portions70,86of the image sensors50,78, the image sensors50,78can be mounted on the carriage51. Accordingly, an operation of connecting the electric cable77becomes simple, and a possibility of contacting the upper surfaces63,79of the image sensors50,78while working is decreased. Further, the carriage51is reduced in size, and thus the costs of the carriage51can be decreased.

Moreover, by providing the cable holders87,88on the image sensor78and by locking the electric cable77by the cable holders87,88, a position in the primary scanning direction for the electric cable77to be extended from the image sensor78can be set at a desired position, regardless of the position of the connector portion86. Further, since the cable holders87,88restrain the movement in the longitudinal direction of the electric cable77, the electric cable is held loosely between the connected portion86and the cable holders87,88, thereby preventing transmission of load via the electric cable77to the connecting position of the connector portion86and the electric cable77. Accordingly, even when the electric cable77changes in posture along with the reciprocating movement of the carriage51, excessive load will not be generated at the connecting position of the connector portion86and the electric cable77.

Second Embodiment

A second embodiment for carrying out the present invention will be described usingFIG. 14andFIG. 15mainly about differences from the first embodiment.

The longitudinal direction of a case49of an image sensor50is the primary scanning direction for reading an image. The length in the primary scanning direction, namely the length in the longitudinal direction of the case49of the image sensor50is the length corresponding to a recording-objective medium of the maximum size readable by the image sensor50. The image sensor50has a length corresponding to a recording-objective medium of A4 size.

In the case49of the image sensor50, positioning portions66are provided. First and second positioning portions66,66′ are for positioning, with respect to the carriage51, in the secondary scanning direction of the image sensor50, namely a direction orthogonal to the primary scanning direction. To describe in detail, the first and second positioning portions66,66′ are formed such that base portions67are provided to project from ends on one of sides in the short direction of the case49of the image sensor50, and shafts68are provided to project in the longitudinal direction from the base portions67respectively. The shafts68engage with shaft receiving portions73, which will be described later, of the carriage51, and thus the image sensor50is positioned in the secondary scanning direction.

The first and second positioning portions66,66′ are each provided at an end on a side in the short direction of the case49of the image sensor50. This pair of the positioning portions66,66′ are arranged at predetermined positions with respect to a reference position C in the longitudinal direction of the case49, regardless of the length in the longitudinal direction of the case49of the image sensor50. In other words, in either case of the image sensor50corresponding to the A4 size or an image sensor78which corresponds to A3 size and which will be described later, the positioning portions66,66′ are arranged at the same positions with respect to the reference position C in the longitudinal direction of the case49. This reference position C is at the center in the longitudinal direction of the case49. As shown in the diagram, the positioning portions66,66′ are arranged in the vicinities of both ends, respectively, in the longitudinal direction of the case49, at each of which a distance L1separated in the longitudinal direction from the reference position C for the positioning portions66,66′ is constant regardless of the length in the longitudinal direction of the case49. Note that although in this embodiment the respective distances L1from the reference position C for the respective positioning portions66,66′ are equal, the respective distances L1for the pair of the positioning portions66,66′ need not be equal as long as the distances from the reference position C are constant.

Further, in the second positioning portion66′, a recess93is formed. This recess93is for positioning in the primary scanning direction of the image sensor50by engaging with a projecting portion77of the carriage51which will be described later. This recess93is also arranged at a predetermined position with respect to the reference position C in the longitudinal direction of the case49, namely a position separated by the distance L2in the longitudinal direction of the case49from the reference position C regardless of the length in the longitudinal direction of the case49of the image sensor50.

As shown inFIG. 15, the carriage51is in a container form for mounting the image sensor50thereon. The carriage51has a bottom portion71and walls72provided to stand upward from both sides in secondary scanning direction of the bottom portion71. In a space formed by the bottom portion71and the walls72, the image sensor50is accommodated. No wall is provided on both sides in the primary scanning direction of the bottom portion71, and one end of the case49of the image sensor50projects from a side in the longitudinal direction of the carriage51.

As shown inFIG. 15, on one of the walls72, the shaft receiving portions73(engaging portion) for engaging with the first and second positioning portions66,66′ are formed. Each of the shaft receiving portions73is formed such that a long hole75in a vertical direction is bored in a projecting piece74provided on the wall72to project upward. By inserting the shafts68of the positioning portions66,66′ through the long holes75, the positioning portions66,66′ and the shaft receiving portions73are engaged. The shaft receiving portions73are arranged at positions corresponding to the pair of the positioning portions66,66′. Therefore, the distance in the longitudinal direction between the pair of the shaft receiving portions73corresponds to the distance in the longitudinal direction of the case49between the positioning portions66,66′, namely approximately the double of the distance L1.

As shown inFIG. 15, on a side of the wall72at which one of the shaft receiving portions73is formed, the projecting portion77(engaging portion) is formed corresponding to the recess93of the second positioning portion66′. In a state that the shafts68of the positioning portions66are inserted into the holes75of the shaft receiving portions73, the case49of the image sensor50is pivoted with respect to the carriage51so that the recess93engages with the projecting portion77, and thus the positioning in the primary scanning direction is made.

It should be noted that although in this embodiment the positioning in the secondary scanning direction is made by the positioning portions66,66′ provided on the case49of the image sensor50and the positioning in the primary scanning direction is made by the recess93, the positioning of the image sensor50with respect to the carriage51by the positioning portions66,66′ and the recess93is an example, and hence their shapes, positioning directions and so forth may be changed.

Method of Producing the Image Reader

A method of producing the above-described image reader according to the present invention will be described briefly usingFIG. 16.

First, there is produced an image sensor having an engaging portion formed at a predetermined position in a longitudinal direction from a reference position of the image sensor (S1), regardless of the length of the image sensor.

Second, there is produced a carriage which is common to image sensors with various lengths and which has an engage-objective portion to be engaged with the engaging portion (S2).

Third, the engaging portion of the image sensor is engaged with the engage-objective portion of the carriage to thereby mount the image sensor in the carriage (S3).

Fourth, the image sensor mounted in the carriage and other parts are assembled with a body of an image reader, thereby completing the image reader as shown inFIG. 1andFIG. 2(S4).

It should be noted that, in the above-described embodiments, although the cable holders87,88are provided only to the image sensor78corresponding to the A3 size, it is needless to mention that similar cable holders can be provided to the image sensor50corresponding to the A4 size to obtain the same effect.

In the above-described embodiments, an example of each of the image sensors50,78is shown, but an image sensor having a different structure may be used within the scope of the present invention.