JPH0626414B2 - Image reader - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an image reading apparatus capable of setting a reading start position before starting the reading operation of an original, and more particularly to dividing a color image of the original into plural times for each color. The present invention relates to an image reading device for reading and scanning.

[Technical Background of the Invention and Problems of Background Art] Generally, in an image reading apparatus for reading and scanning a color image of a document in plural times for each color, an image is read between image data read by each reading scan. The reading start position must be accurately defined so that the shift of the position does not occur. Therefore, in the conventional image reading apparatus, the actuator is turned on when the actuator comes into contact with the carriage.
A mechanical switch that is turned off is used. However, in the reference position setting method using such a mechanical switch, by repeatedly using this mechanical switch, for example, the actuator is deformed, the on-off position is deviated, and the reference position is extremely accurate. For example, it has been pointed out that the accuracy cannot be specified at about 1/16 mm.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to set a reading reference position for setting a reading start position of an image extremely accurately. It is an object of the present invention to provide an image reading device capable of reproducing a good color image without deviation.

[Outline of the Invention] In order to achieve the above-mentioned object, an image reading apparatus according to the present invention includes an image reading area and a home position area provided adjacent to the image reading area, and color images of an original are classified by color. An image reading apparatus that reads and scans a plurality of times separately, wherein a carriage that is provided so as to be movable along the reading scanning direction, and the carriage that scans the carriage along the scanning direction in the image reading area and the home position area, After the scanning of the image reading area is completed, a drive mechanism for moving the image reading area to the home position area so as to be returned in a direction opposite to the scanning direction, and a position provided in the home position area for starting the scanning of the image reading area. A reference position setting member having a detection surface to be defined,
A photoelectric converter having a plurality of photoelectric conversion elements, which is attached to the carriage and optically reads an image of a document placed on an image reading area, and optically reads a detection surface of the reference position setting member; Of the photoelectric conversion elements that have read the detection surface of the reference position setting member, the number of photoelectric conversion elements that have reached a predetermined level is counted, and the time when the count reaches a predetermined number is defined as the read reference position, and the photoelectric conversion is performed. And a determination unit for setting a reading start position of the image by the container to the downstream side along the scanning direction by a predetermined distance with respect to the reading reference position.

[Embodiment of the Invention] An embodiment of an image reading apparatus according to the present invention will be described below.
The details will be described with reference to the accompanying drawings.

As shown in FIG. 1, the image reading device 10 includes a box-shaped main body 12. An opening 12a is formed in the upper portion of the main body 12 so as to correspond to the image reading area N.
A pair of side plates 14a, 14b facing each other are provided on the lower surface of the upper portion of the main body 12 so as to sandwich the opening 12a and extend in the image reading / scanning direction indicated by the arrow X. There is.

On the screens of the first and second side plates 14a and 14b facing each other, as shown in FIG. 2, first and second rails 16a and 16b defined as guide members are arranged along the image scanning direction X. Are extended and attached respectively. Guide rails 18a and 18b are formed in the rails 16a and 16b, respectively. A carriage 20 is provided so as to be capable of reciprocating along the image scanning direction X so as to scan the image reading area N while being guided by the pair of rails 16a and 16b.

The carriage 20 includes a carriage body 22 having a through hole 22a formed long along the width direction orthogonal to the image scanning direction X. A stopper arm 22b is provided on the side of the second rail 16b of the carriage body 22 for restricting clockwise rotation of a lever member 24, which will be described later. A mirror 26 is attached to the lower surface of the carriage body 22. The mirror 26 includes a pair of halogen lamps 28a, which are arranged along the width direction,
28b is detachably attached. The positions of the halogen lamps 28a and 28b are regulated so that the light emitted from the halogen lamps 28a and 28b is reflected by the mirror 26 and condensed on the original surface of the original placed on the image reading area N.

In addition, the carriage main body 22 cuts only the infrared component from the reflected light so as to be positioned in the optical path of the reflected light from the document, and eliminates the adverse effect of the infrared light on the sensor described later. An external light cut filter 30 is provided. Further, in the optical path of the reflected light, an imaging element (trade name) configured by arranging a plurality of converging optical transmission bodies in two rows in a state of being located after the infrared light cut filter 30. : Selfoc lens) 32 is provided.

A photoelectric converter 34 that photoelectrically converts the reflected light that has been imaged is attached to the carriage body 22 at a position where the reflected light from the document is imaged by the imaging element 32. The photoelectric converter 34 is configured by arranging silicon photo cells of 862 pixels in a line. A filter mechanism 36 is provided between the image forming element 32 and the photoelectric converter 34 to decompose the reflected light from the document, which is condensed by the image forming element 32, into three types depending on the wavelength.

The filter mechanism 36 is provided with a filter frame 36a movably provided along the image scanning direction X, a red filter R provided in the filter frame 36a and formed in a shape corresponding to the photoelectric converter 34, respectively. A green filter G and a blue filter B are provided. The red filter R means a filter that transmits only the red component in the light that passes through the filter, and the green filter G means a filter that transmits only the green component in the light that passes through the filter. The blue filter B means a filter that transmits only the blue component in the light that passes through this filter.

Here, the filters R, G, and B are set so as to be separated from each other by the same distance L along the image scanning direction X. The filters R, G, B are arranged on the same plane,
As the position of the filter frame 36a is switched by the switching mechanism 74 described later, in other words, as the position of the filter frame 36a is relatively changed with respect to the carriage body 22, the image forming elements are selectively formed. It is located in the optical path of the reflected light between the child 32 and the photoelectric converter 34. The filters are arranged such that the green filter G is placed in the center, and the red filter R is arranged on the upstream side and the blue filter B is arranged on the downstream side in the image scanning direction X.

As shown in FIGS. 3 and 4, in the portion of the carriage main body 22 on the side of the first rail 16a, a pair of first and second members arranged along the document scanning direction X at a predetermined interval. The second support shafts 38a and 38b are provided so as to stand down with their positions fixed. Each support shaft 38a, 38
The first and second guide rollers 40a and 40b, which slidably contact the first guide groove 18a described above, are rotatably attached to b.

On the other hand, as described above, the lever member 24 is rotatably attached to the portion of the carriage body 22 on the second rail 16b side. That is, in the portion of the carriage main body 22 on the side of the second rail 16b, the above-mentioned first and second
The third support shaft 42 is provided upright while being positioned between the support shafts 38a and 38b. This third support shaft 42
The lever member 24 has one end rotatably attached thereto. The fourth support shaft 4 is provided at the center of the lever member 24.
4 are provided upright. A movable guide roller 46 is rotatably attached to the fourth support shaft 44. The movable guide roller 46 is provided on the second rail 16
so as to slidably contact the second guide groove 18b of b,
Its position is prescribed.

Here, a torsion spring 48 is wound around the third support shaft 42. One end of the torsion spring 48 is in contact with the carriage main body 22, and the other end is the lever member 2.
4, the lever member 24 is biased so as to rotate counterclockwise in FIG. That is, the movable guide roller 46 is biased by the biasing force of the torsion spring 48 so as to come into pressure contact with the second guide groove 18b.

Here, the other end of the lever member 24 causes the carriage main body 22 to rotate clockwise or counterclockwise when a shock is applied to the stopper arm 22b of the carriage main body 22 at the start of reading scanning or during scanning. In any case, the movable guide roller 46 is pushed toward the carriage 20 and abuts against the carriage 20 to prevent the carriage 20 from tilting, when the carriage 20 rotates in the direction and tries to tilt.

Next, the carriage drive mechanism 50 for moving the carriage 20 along the document scanning direction X will be described.

As shown in FIG. 1, the first pulley shaft 52a is freely rotatable between the first and second side plates 14a and 14b so as to be located downstream of the document reading area in the document operating direction X. Is attached to. On the other hand, so that it is located upstream of the document reading area in the document operating direction X,
A mounting plate 54 is provided between the first and second side plates 14a and 14b.
Is fixedly provided. A bent piece 54a is integrally provided in a portion of the mounting plate 54 on the first side plate 14a side in a standing state. Between the bent piece 54a and the first side plate 14a, the first pool shaft 52a described above is provided.
A second pulley shaft 52b is rotatably attached in parallel with the.

A first pulley 56a is fixedly attached to such a portion of the first pulley shaft 52a on the first side plate 14a side. On the other hand, the second pulley 56b is fixedly attached to the portion of the second pulley shaft 52b facing the first pulley 56a.

On the other hand, as shown in FIG. 5, a wire 58 as a driving force transmission medium is wound between the first and second pulleys 56a and 56b. One end of the wire 58 is fixed to the protruding end of the first support shaft 38a described above,
The other end of 8 is fixed to a mounting piece 22c formed integrally with the carriage body 22 via a coil spring 60. In this way, the carriage 20 is moved by the rotation of the first pulley shaft 52a.

The carriage drive mechanism 50 further includes a pulse motor 62 as a drive source, as shown in FIG. The drive source does not have to be the separate pulse motor, and may be, for example, a motor including an encoder and capable of controlling the rotation amount. A drive force transmission mechanism 64 that transmits the drive force of the pulse motor 62 is provided between the drive shaft 62a of the pulse motor 62 and the first pulley shaft 52a.

The driving force transmission mechanism 64 includes a gear unit 64a that reduces and transmits the rotation speed of the pulse motor 62, and a timing belt 64b that transmits the reduced driving force of the gear unit 64a to the first pulley shaft 52a. There is. In this way, the carriage 20 is moved and driven in the image scanning direction X by the driving force of the pulse motor 62.

On the other hand, the platen glass 66 is provided to close the opening 12a formed in the main body 12 corresponding to the image reading area N described above. This image reading device 1
A document whose image is read by 0 is placed on the platen glass 66 with the document surface facing down. Further, in order to fix the platen glass 66 to the main body 12, first and second platen glass pressing plates 68a and 68b are attached to the downstream and upstream edge sides of the platen glass 66 in the image scanning direction X. ing.

Here, as shown in FIG. 6, the lower surface of the second platen glass holding plate 68b located on the upstream side in the image scanning direction X is adjacent to the side edge of the platen glass 66, that is, image reading is performed. The reference position setting member 70 of the carriage 29 is attached to a position deviated from the region N along the image reading direction X. This reference position setting member 70
Is a black first member 70a extending in the width direction and having a recess formed in the lower surface, and a white second member 70b embedded in the recess and having the lower surface exposed. It consists of and.

The first member 70a is formed by subjecting an aluminum plate material to black alumite treatment. On the other hand, the second member 70b is formed of a white ceramic plate. That is, in the reference position setting member 70, the white band portion Wh and the black band portion Bl located adjacent to the image reading region N side of the white band portion Wh are located in the portion scanned by the movement of the carriage 20. It will be equipped with a detection surface.

The photoelectric conversion unit 34 described above changes the detection level from the white level detected in the white band portion Wh to the black level detected in the black band portion Bl, thereby electrically reading and scanning. Has set the start position for. On the other hand, the white band portion Wh also has a function of setting a reference white level at the time of reading scanning and determining the range of the reading level in the photoelectric converter 34. Based on the white level set in the white band portion Wh, the correction of the change in the light amount of the pair of halogen lamps 28a and 28b and the shading correction are executed.
Specifically, these corrections are performed with the filters G, B, and R being switched and mounted, the white band Wh is read each time before each image reading scan, and the white data is used as reference data as described above. And is stored in the control circuit.

Further, as shown in FIG. 1, a reset switch 72 for defining the driving timing of the pulse motor 62 is attached to the lower surface of the attachment plate 54 at the substantially central portion in the width direction. The reset switch 72 is turned on when one side edge of the carriage 20 facing the reset switch 72 is pushed in by pushing the actuator 72a of the reset switch 72 along with the return operation of the carriage 20, and one side edge of the carriage 20. Is separated from the actuator 72a to be turned off. In other words, the carriage 20 is set to move until one side edge of the carriage 20 passes the image reading area N and the reset switch 72 is turned on.

The range from the black band Bl to the reset switch 72 described above is defined as the home position area H.

Next, the switching mechanism 74 for switching the position of the filter frame 36a in the above-described filter mechanism 36 will be described with reference to FIGS. 7 to 9.

As shown in FIG. 7, the first and second side plates 14a, 14
As a working member, a position b is not in contact with the carriage main body 22 but in contact with the filter frame 36a at a position which is located at the distance L described above on the home position region H side from the black band Bl described above. The first and second protrusions 76a and 76b are provided respectively. Where the first
Alternatively, the distance between the second protrusions 76a and 76b and the reset switch 72 described above is set to correspond to twice the distance L described above.

On the other hand, on the upper surface of the portion of the carriage main body 22 on which the filter frame 36a is placed, a pair of filter frame guide rails 78a and 78b are provided to support the filter frame 36a so as to be movable along the image scanning direction X. Are attached in parallel with each other in a state of extending along the image scanning direction X. On the lower surface of the filter frame 36a, a pair of grooves 80a, 80 fitted into these guide rails 78a, 78b are provided.
b is formed. These guide rails 78a, 78
The filter frame 36a is supported so as to surely slide along the image scanning direction X by fitting b into the grooves 80a and 80b, respectively.

A pair of coil springs 82a and 82b are attached between the filter frame 36a and the carriage body 22. These coil springs 82a, 82b
Urges the filter frame 36a to move in a direction opposite to the document scanning direction X.

Above the filter frame 36 described above, filter groups B, G,
A pair of cam grooves 84 and 86 are formed so as to be located on both sides of R. On the other hand, the carriage main body 22 has a pair of locking claws 88 and 9 which are respectively locked to the cam grooves 84 and 86.
0 is attached. That is, the first locking claw 88 is locked in the first cam groove 84 on the side of the first side plate 14a, and the second cam groove 86 is set in the second cam groove 86 on the side of the second side plate 14b.
The locking claw 90 is locked.

The first and second cam grooves 84, 86 and the first and first locking claws 88, 90 are formed in symmetrical shapes centering on the filter groups G, B, R placed therebetween. There is. Therefore, in the following description, the first side plate 14a
The first cam groove 84 and the first locking claw 88 on the side will be described as a representative, and the description of the second cam groove 86 and the second locking claw 90 will be omitted.

As shown in FIG. 8, the first cam groove 84 is connected to a linear groove portion 84a extending along the image scanning direction X and one end portion of the linear groove portion 84a on the upstream side in the image scanning direction X. A curved D-shaped groove 84b having one end protruding toward the first side plate 14a and having the other end connected to the vicinity of the other end of the linear groove 84a is formed in a substantially D shape. ing.

The straight groove portion 84a is formed so as to have a predetermined first depth D ₁ . First and second protrusions 84c and 84d are formed at a distance L along the image scanning direction X in the middle of the straight groove portion 84a. Also,
The distance between the second protrusion 84d and one end of the straight groove 84a is set to be shorter than the distance L between the filters. First protrusion 84c and second protrusion 84c
Is an inclined surface whose height gradually increases along a direction opposite to the image scanning direction X, and a second depth D where the top of this inclined surface is shallower than a predetermined first depth D _{1. The} upright surface is provided upright at a position having ₂ .

The depth of one end of the straight groove portion 84a and the detour groove portion 84b
The depth of one end of each is set to the _first depth D ₁ . On the other hand, the portion from the middle of the detour groove portion 84b toward the other end portion is provided so as to be inclined so that the depth thereof gradually decreases. That is, bypassing the other end of the groove 84b, the depth is first depth D shallower than ₁ third depth D ₃
Is set to.

On the other hand, the filter frame 36 of the carriage body 22 described above.
A support shaft 92 is provided upright in a portion located downstream of the position a in the image scanning direction X. A locking lever 94 is pivotally attached to the support shaft 92. That is, the locking lever 94 is attached to the support shaft 92 so as to be rotatable around the support shaft 92 in a horizontal plane and movable along the support shaft 92 in a vertical plane. As shown in FIG. 7, the locking lever 94 is provided with a first locking claw 88 that engages with the above-described first cam groove 84 in a state of being bent downward at the tip portion thereof. .

As shown in FIG. 9, the support lever 92 has a locking lever 9
4 is urged downward, and as shown in FIG. 7, the locking lever 94 is moved clockwise in the figure, that is, the first side plate 14
A spring 96 for urging so as to rotate toward a is attached. In other words, the spring 96 includes a coil spring portion 96a that biases the locking lever 94 downward and a torsion spring portion 96b that biases the locking lever 94 laterally. In this way, the first locking claw 88 has its lower end abutted on the bottom surface of the first cam groove 84.
Moreover, the side surface of the first side plate 14 of the first cam groove 86 is
It is biased so as to come into contact with the side surface on the a side.

With such a configuration, the filter frame 36a is always urged by the pair of coil springs 82a and 82b in the direction opposite to the image scanning direction X, in other words, toward the home position region H, but the first Since the locking claw 88 of is locked in the first cam groove 84, its position is held according to the locking position. That is, the end surface of the first cam groove 84 on the downstream side in the image scanning direction X is defined as the blue filter setting surface S _B , and the upright surface of the first protrusion 84c is the green filter setting surface S _G. The upright surface of the second protrusion 84d is defined as the red filter setting surface S _R.

Here, by engaging the above-described first locking claw 88 with the blue filter setting surface S _B , the blue filter B of the filter mechanism 36 is positioned in the optical path of the reflected light, and the green filter is also provided. by engaging in use setting surface S _G, the green filter G of the filter arrangement 36 is to be positioned in the optical path of the reflected light, further, as shown in FIG. 9, in the setting surface S _R for red filter By engaging, the position of the red filter R of the filter mechanism 36 is switched so that it is located in the optical path of the reflected light.

In the image reading apparatus 10 configured as described above,
The image reading operation will be described below.

First, the case where the original has a color image surface and the color image surface is read will be described.

When the main switch (not shown) of the image reading device 10 is turned on, the control circuit operates to cause the carriage 20 to move.
Whichever position is present, the pulse motor 62 is driven to return to the home position region H. Along with this return operation, the filter frame 36a of the filter mechanism 36 provided on the carriage 20 has the first and second side plates 1
First and second protrusions 7 provided on 4a and 14b, respectively
It contacts 6a and 76b. In this way, in the filter mechanism 36, even if any filter is located in the optical path of the reflected light before the return operation of the carriage 20, the filter located in the downstream side with respect to the image scanning direction X, That is, in this embodiment, the blue filter B comes to be located in the optical path of the reflected light. First, this operation will be described in detail.

With the red filter R positioned in the optical path of the reflected light, that is, with the locking claws 88 and 90 locked to the red filter setting surface S _R , the carriage 20 moves as described above.
The pulse motor 62 is moved in the direction opposite to the image scanning direction X. In this movement, the carriage 20
When the filter frame 36a is in the home position area H, the filter frame 36a abuts the first and second projecting portions 76a and 76b and their movement is prohibited.
2 will be further moved by a distance more than twice the distance L.

In other words, since the first and second locking claws 88 and 90 are attached to the carriage body 22, even after the movement of the filter frame 36a is stopped, the first and second locking claws 88 and 90 are moved by a distance twice the distance L. Will be done. That is, the first and second locking claws 88 and 90 are moved in the directions opposite to the image scanning direction X in the linear groove portions 84a of the first and second cam grooves 84 and 86, respectively. Become. Here, the first and second locking claws 88 and 90 are respectively moved to the first position by the second spring 96b.
And, since it is urged in the direction toward the second side plates 14a, 14b, when reaching one end of the linear groove portion 84a,
It will enter one end of the bypass groove portion 84b.

In this way, as the carriage 20 is moved along the image scanning direction X thereafter, the filter frame 36b
Are disengaged from the first and second protrusions 76a and 76b, and the filter frame 36a is moved in the direction opposite to the image scanning direction X by the biasing force of the first and second coil springs 82a and 82b. Be moved. Therefore, the first and second locking claws 88, 90 relatively come into contact with the other end surface of the straight groove portion 84a, that is, the blue filter setting surface S _B via the bypass groove portion 84b. . That is, the carriage 2
With the return operation to the home position area H of 0, the blue filter B is located in the optical path of the reflected light.

The above description has been made in the case where the red filter R is previously positioned in the optical path of the reflected light, but also when the green filter G is previously positioned in this optical path, that is, the locking claw 88. , 90 are also locked to the green filter setting surface S _G , the carriage main body 22 moves by a distance twice the distance L after the filter frame 36a is stopped. Similarly to the case, with the returning operation of the carriage 20 to the home position area H,
The blue filter B comes to be located in the optical path of the reflected light.

In this way, no matter what filter is located in the optical path of the reflected light before the return operation of the carriage 20,
With the return operation of the carriage 20 to the home position area H, the image scanning direction X is always included in the optical path of the reflected light.
With respect to the downstream filter, namely the blue filter B
Will be located.

The carriage 20 is returned to the home position area H,
After waiting, for example, the power of a printer or a CRT (not shown) to which the image reading device 10 is connected is turned on. In response to this CRT start signal, the control circuit of the image reading device 10 starts the control operation.

With this start, as shown in FIG. 10, the halogen lamps 28a and 28b are turned on, and the home position area H
The reference position setting member 70 at is started to be captured by the photoelectric converter 34. That is, first, the white second member 70b
The reference white level of the white band portion Wh of is read through the photoelectric converter 34, and this data is stored as reference data. At this time, the shading correction and the correction of the change in the light amount of the halogen lamps 28a and 28b are simultaneously performed.

On the other hand, with the start of this control operation, the driving of the pulse motor 62 is started, and the carriage 20 starts moving along the image scanning direction X. In this way, the photoelectric converter 3
4 optically catches the black band Bl of the first member 70a. Here, the number of bits at which the output level from each pixel of the photoelectric converter 34 reaches the black determination level is measured, and the position at which the number of bits reaches a predetermined number is defined as the read reference position O _1. The read reference position O ₁ is stored in the control circuit.

That is, specifically, the output of the photoelectric converter 34 is input to the A / D converter. Where this A / D
A value of 1/4 full scale of the input level of the converter is defined as the read reference level. The numerical value of 1/4 may be 1/2 or 1/8, and the numerical value is not limited. Here, by defining the reading reference level to 1/2 ⁿ of full scale, the output of the A / D converter can be used as it is as the detection result. Further, the reason why this numerical value is reduced to ½ or less is that the predetermined white level may drop to ½ in the worst case due to the shading characteristics. Furthermore,
By setting to 1/4 as in this embodiment,
The black level setting need not be pure black, and the setting is simplified.

The reading reference position O ₁ is set at a position where the output from all the silicon photocells (pixels) forming the photoelectric converter 34 changes from the white level to the black level, or one photocell. Is not the position where the white level has changed to the black level, but the reading reference position O ₁ is the position where 2 ⁿ photocells are changed in the 862 pixels, and 64 photocells are changed in this embodiment. By setting in this way, for example, dust is attached on one photocell and it is determined that one photocell is black, or some reflection causes one photocell to be white. Even if it is determined that the reading reference position O ₁ exists, the reading reference position O ₁ can be accurately defined. Further, by setting the number of changed photocells to 2 ⁿ , the number of photocells changed to the black level is counted by the counter, and if the overflow in this counter is noted, it can be easily detected.

After the read reference position O ₁ is stored in the control circuit in this manner, the pulse motor 6 is read from the read reference position O _1.
The number of drive pulses to 2 is measured, and the position of the carriage 20 at which the number of pulses reaches a predetermined value is the reading start position O ₂
Stipulate. Then, the reading operation of the image by the photoelectric converter 34 from this reading start position O ₂ , and more specifically, the reading operation of the light reflected from the original and transmitted through the blue filter B is started.

In this reading operation, the carriage 20 is guided by the first and second rails 16a and 16b and moved in the image scanning direction X. Here, the carriage 20 is supported on the first rail 16a by the guide rollers 40a and 40b, and is moved by the movable guide roller 46 to the second rail 16a.
Is supported by the rail 16b. In such a configuration, the movable guide roller 46 is constantly urged by the torsion spring 48 toward the second rail 16b. In other words, the carriage 20 has this torsion spring 48.
Thus, the first rail 16a is biased. In this way, the carriage 20 is mounted on both rails 1
6a and 16b are elastically supported, and all guide rollers 40a, 40b and 46 are always supported by the corresponding rails 16a and 1b.
6b will be transposed, and in this way, even if
Even if the parallelism of both rails 16a, 16b is a little off,
When the carriage 20 travels, rattling of the carriage 20 is prevented.

Further, the first rail 16a functions as a reference rail, and the guide roller 4 is attached to the first rail 16a.
0a and 40b are always in rolling contact, so the carriage 20
The position of is stable, and thus the moving state of the photoelectric converter 34 is also maintained stably.

Further, the guide rollers 40a and 40b are connected to the first rail 16
a, and the movable guide roller 46 is attached to the second rail 16
Since each of them elastically rolls against b, even if an impact is applied to the image reading device 10 while the carriage 20 is running, engagement between the guide rollers 40a and 40b and the first rail 16a, And the movable guide roller 46 and the second
Does not come out of engagement with the rail 16b, that is, there is no possibility that the carriage 20 comes out of both rails 16a and 16b. In this way a good read operation is performed.

The data read by this reading operation is sequentially output to the printer or CRT according to their operating speed. The reading speed of the image reading apparatus 10 is variable according to the operating speed of the printer or CRT.

In the reading operation described above, as described above,
First, the blue filter B is used to read only the blue image of the document. When the reading operation of the blue portion of the document is completed, the carriage 20 is returned to the home position area H. Here, the read reference position O ₁ already stored in the control circuit is reached. The read reference position O ₁ at the time the carriage 20 passes, the projecting portions 76a which are spaced apart in a direction opposite from the read reference position O ₁ to the distance L image scanning direction X, filter 76b frame 3
6a abuts each other, and the carriage 20 further moves by the distance L, so that the filter frame 36a of the filter frame switching mechanism 74 has the first and second locking claws 88 and 90 engaged with the blue filter setting surface S _B. It is switched from the stopped position to the position locked by the green filter setting surface S _G. In this way, the green filter G is positioned in the optical path of the reflected light.

After that, the carriage 20 starts to be moved along the image scanning direction X. First, by the photoelectric converter 34,
As described above, the reference white reading operation is performed on the incident light that has passed through the green filter G. The read white data is stored in the control circuit as in the case of the blue filter B at the previous time. Further, as in the case of the blue filter B of the previous time, by measuring the reading reference position O ₁ that is changed from the white level to the black level and the predetermined number of pulses from the time when the reading reference position O ₁ is passed, The reading start position O ₂ will be defined again.

In this way, the green image of the original is read and scanned by the photoelectric converter 34, and then the carriage 20 is returned to the home position area H again.

Here, the read reference position O ₁ already stored in the control circuit
Leading to. When the carriage 20 moves the distance L after passing through the reading reference position O ₁ , the protrusions 76a,
The filter frame 36a contacts the 76b. On the other hand, after the carriage 20 passes the reading reference position O ₁ , the carriage 20 moves further by a distance corresponding to twice the distance L this time. In this way, the filter frame 3
6a moves relative to the carriage body 22 by the distance L. Therefore, the filter frame 36a of the filter frame switching mechanism 74 has the first and second locking claws 8a.
8 and 90 are switched from the positions locked by the green filter setting surface S _G to the positions locked by the red filter setting surface S _R. In this way, the red filter R is located in the optical path of the reflected light.

After that, the carriage 20 starts to move again along the image scanning direction X. First, the photoelectric converter 34 performs the reference white reading operation on the incident light passing through the red filter R as described above. To be executed. The read white data is stored in the control circuit as in the case of the previous green filter G. Further, as in the case of the green filter G of the previous time, by measuring the reading reference position O ₁ that is changed from the white level to the black level and a predetermined number of pulses from the time when the reading reference position O ₁ is passed, The reading start position O ₂ will be defined again.

In this way, the red image of the original is read and scanned by the photoelectric converter 34, and then the carriage 20 is returned to the home position area H again.

In this way, a series of color image reading operations is completed.

When the color image reading operation is completed in this way, the carriage 20 moves the home position area H by the control circuit.
To the position until the reset switch 72 is turned on. That is, when the carriage 20 is moved by a distance corresponding to three times the distance L from the reading reference position O _1.
Is stopped. On the other hand, since the filter frame 36a is held at the position where the locking claws 88 and 90 are locked to the red filter setting surface S _R , the filter frame 36a is twice the distance L from the read reference position O _1. When it advances by a distance corresponding to, it comes into contact with the protrusions 76a and 76b and is prevented from moving thereafter. In this way, the locking claws 88, 90
Is advanced by a distance L from the red filter setting surface S _R , and as a result, the locking claws 88 and 90 are urged by the first and second springs 96a and 96b, so that the detour groove 8 is formed.
It is in a state of being locked to the blue filter setting surface S _B through 4b.

In this way, after the series of color image reading operations is completed, the carriage 20 is returned to the home position area H, and thus the initial state, that is, the state in which the blue filter B is positioned in the optical path of the reflected light is obtained. Will be restored.

In the image reading apparatus 10 configured and operated as described above, the filter mechanism 36 is switched by the switching mechanism 74 so that the filters R, G, B are selectively positioned in the optical path of the reflected light. Become. Here, even if the filters R, G, B are switched, the output level of the photoelectric converter 34 does not change and a constant output level can be maintained so that both halogens can be maintained as shown in FIG. Lamp 2
8a and 28b and the power supply 100 that applies a voltage to them, the power supply 100 according to a control signal from the control circuit.
A first regulation circuit 102 that changes the voltage from is connected.

The configuration of one embodiment of the first regulation circuit 102 will be described below.

As shown in FIG. 11, one input terminal 104a of the voltage input terminals 104a and 104b connected to the power supply 100.
Is connected to one output terminal 108a via the first npn-type transistor 106. The other input terminal 104b is directly connected to the other output terminal 108b by a ground line. Here, the input terminal 104
A first electric field capacitor 110a is connected between a and 104b. On the other hand, the second electric field capacitor 110b is also connected between the output terminals 108a and 108b.
The first and second terminals are placed between the output terminals 108a and 108b.
Halogen lamps 28a and 28b are connected in parallel.

A resistor is connected between the collector and the base of the first transistor 106. The base of the first transistor 106 is connected to the collector of the second transistor 112. This second transistor 11
The second emitter is connected to the ground line via the Zener diode 114 and the capacitor 116 in parallel. On the other hand, the emitter of the first transistor 106 and the second
The transistor 112 and the emitter of the transistor 112 are connected to each other through a resistor. Further, the base of the second transistor 112 is connected to the base of the first transistor 106 via the first resistor 118 and to the ground line via the second resistor 120, respectively.

With this configuration, the voltage V _{A at} the connection point A between the first and second resistors 118 and 120 is equal to the second transistor 11
It is defined by a value obtained by adding the base-emitter voltage V _{BE in 2} and the Zener voltage V _Z in the Zener diode 114. As is well known, this voltage V _A is designed to be maintained at a constant voltage value.

The first control circuit 102 has first and second control signal input terminals 122 to which a control signal from the control circuit is input.
a and 122b are provided. The first control signal input terminal 122a is connected to the base of the third transistor 124 via a resistor. On the other hand, the second control signal input terminal 122b is connected to the base of the fourth transistor 126 via a resistor. These third and fourth
Of the transistors 124 and 126 function as switches that are turned on by a control signal of "H" level and turned off by a control signal of "L" level.

Here, the collector of the third transistor 124 is
Of the fourth transistor 12 through the resistor 128 of
The collector of 6 is connected to the connection portion A between the first and second resistors 118 and 120 via the fourth resistor 130, respectively.

With such a configuration of the first regulating circuit 102, the voltage V ₀ applied between the output terminals 108a and 108b is the voltage V _A at the point A, which is the resistance value R ₁ and the resistance value R of the _first resistor 118. _The value is divided by _V and resistance.

That is, V ₀ is defined by the following equation.

Here, R _V is the second to fourth resistors 120, 128,
This is a resistance value calculated by the parallel resistance values of the resistance values R ₂ , R ₃ , and R ₄ of 130.

On the other hand, the first and second control signal input terminals 122a, 12
A control signal determined according to the selected filter is input to 2b. That is, this control circuit pays attention to the fact that each color temperature changes depending on the color of the selected filter, in other words, the color of the light incident on the photoelectric converter 34. Even if the filter is selected, the exposure amount of the halogen lamps 28a, 28b, that is, the voltage applied to the halogen lamps 28a, 28b is regulated so that the output level from the photoelectric converter 34 becomes constant.
Outputs a control signal.

Specifically, when the blue filter B is selected, an "H" level signal is input to the first control signal input terminal 122a and an "L" level signal is input to the second control signal input terminal 122b.
Level signals are input respectively. When the green filter G is selected, the first control signal input terminal 122a
Is input to the second control signal input terminal 122b, and an "H" level signal is input to the second control signal input terminal 122b.
Further, when the red filter R is selected, the "L" level signal is input to the first control signal input terminal 122a and the "L" level signal is input to the second control signal input terminal 122b. Is entered.

Here, as described above, each of the third and fourth transistors 124 and 126 is turned on when the "H" level signal is input, and turned off when the "L" level signal is input. . That is, when the "H" level signal is input to the first control signal input terminal 122a, the third transistor 124 is turned on, and thus the third resistor 12 is turned on.
The resistance value R _{3 of} 8 will contribute to the calculation of the parallel resistance value R _V. On the other hand, "L" is applied to the first control signal input terminal 122a.
When the level signal is input, the third transistor 124
Is turned off, so that the resistance value R ₃ of the third resistor 128 does not contribute to the calculation of the parallel resistance value R _V.

Further, when the "H" level signal is input to the second control signal input terminal 122b, the fourth transistor 126 is turned on, so that the resistance value R ₄ of the fourth resistor 130 is equal to the parallel resistance value R _V. It will contribute to the calculation. On the other hand, when the "L" level signal is input to the second control signal input terminal 122b, the fourth transistor 126 is turned off, and therefore,
The resistance value R ₄ of the fourth resistor 130 will not contribute to the calculation of the parallel resistance value R _V.

In this way, when the blue filter B is selected, the resistance value R _V is calculated by the parallel resistance value of the resistance value R ₃ of the second resistance value R ₂ of the resistor 120 and third resistor 128 It Also, when the green filter G is selected, the resistance value R _V and the resistance value R ₂ of the second resistor 120 of the fourth resistor 13
It is calculated by the parallel resistance value with the resistance value R _{4 of} 0. Further, when the red filter R is selected, the resistance value R _V
Is calculated by the resistance value R ₂ of the second resistor 120 itself.

As described above, according to this embodiment, the applied voltage value to the halogen lamps 28a and 28b, that is, the color temperature characteristic of the light source of the halogen lamps 28a and 28b is changed according to the color characteristics of the selected filter. The output sensitivity from the photoelectric converter 34 is always kept constant due to the temperature characteristic and the color characteristic of the filter.

In this way, in the image reading apparatus 10, the output level is kept constant by keeping the amount of light incident on the photoelectric converter 34 constant. Here, the output signal from the photoelectric converter 34 is converted into a video signal in the processing circuit 132, as shown in FIG. This video signal is subjected to gain adjustment in the gain adjusting unit 134. The gain-adjusted video signal is converted into a digital signal by the A / D converter 136 and output to a CRT or printer (not shown).

Here, in order to improve the image quality in the CRT or the printer, the brightness adjustment is performed in this embodiment. This brightness adjustment is performed by the image reading apparatus 1 as shown in FIG.
This is executed by pressing the brightness changeover switch 140 provided on the panel board 138 of No. 0.

The brightness changeover switch 140 includes a control unit 142.
It is connected to the. The control unit 142 outputs different kinds of control signals to third and fourth control signal input terminals 144a and 144b, which will be described later, in order to switch the brightness level each time the brightness changeover switch 140 is pressed. Has been done. The control unit 142 includes the above-mentioned third and fourth control signal input terminals 144a and 14a.
4b and the second regulating circuit 146 and the A / D
It is connected to the converter 136. The power supply 100 is connected to the second regulation circuit 146.

The configuration of FIG. 12 is specifically shown in FIG.

On the panel board 138 described above, the brightness changeover switch 1
In addition to 40, two light emitting elements 148a and 148b indicating the degree of brightness switched by the brightness switching switch 140 are respectively light emitting elements 148a and 148.
b is connected to the control unit 142. The low brightness is set by pressing the brightness changeover switch 140 once from the state where the normal brightness is set. With this setting, the first light emitting element 148a is turned on. In addition, from the state where this low brightness is set,
By pressing the lightness changeover switch 140 one more time, high lightness is set. With this setting, the second light emitting element 148b is turned on. Furthermore,
From this state, when the brightness changeover switch 140 is pressed once more, the normal brightness is set. With this setting, both the light emitting elements 148a and 148b are turned off.

The control unit 142 also includes first and second control signal output terminals 150a and 150b. The first control signal output terminal 150a is the first control signal input terminal 1
44a, and a second control signal output terminal 150b
Is connected to the second control signal input terminal 144b.

Here, when the normal brightness is set, the "H" level signal and the "L" level signal are output to the first and second control signal output terminals 150a and 150b, respectively. When the lightness changeover switch 140 is pressed once to set the low lightness after the normal lightness is set, the first and second control signal output terminals 150 are output.
a and 150b have an "L" level signal and an "H" level, respectively.
When the level signal is output and the brightness changeover switch 140 is further pressed to set the high brightness, the "L" level signal is output to both the first and second control signal output terminals 150a and 150b. Is being output.

Next, the configuration of the second regulation circuit 146 will be described.

The second regulating circuit 146 is a constant voltage integrated circuit 152.
Is equipped with. The 12v output terminal of the power supply 100 is connected to the input terminal of the constant voltage integrated circuit 152. The input terminal of the constant voltage integrated circuit 152 is connected to the ground terminal of the constant voltage integrated circuit 152, the input terminal of the operational amplifier 154, and the ground terminal of the power supply 100 via a ground line via a capacitor. The output terminal of the constant voltage integrated circuit 152 is connected to the output of the operational amplifier 154 via a capacitor and the fifth resistor 156 having a resistance value R ₅ and the sixth resistor 158 having a resistance value R ₆ in series. It is connected to the terminal. A capacitor is connected in parallel with the sixth resistor 158.

Further, one input terminal of the operational amplifier 154 is connected to the connection ends of the fifth and sixth resistors 156 and 168.
Here, the output terminal of the constant voltage integrated circuit 152 is connected to the other input terminal of the operational amplifier 154 via the resistor 160 having a resistance value R ₇ . The other input terminal of the operational amplifier 154 is connected to the above-mentioned ground line via the eighth resistor 162.

With such a configuration, the seventh and eighth resistors 160, 1
A constant voltage V _C is output to the connecting portion C of 02. The output terminal of the constant voltage integrated circuit 152 is A /
It is connected to the reference voltage input terminal 136a of the D converter 136.

The above-mentioned third control signal input terminal 144a is connected to the base of the fifth transistor 164. This fifth
The collector of the transistor 164 of the
Is connected to the other input terminal of the operational amplifier 154 via. The emitter of the fifth transistor 164 is connected to the ground line.

On the other hand, the second control signal input terminal 144b is connected to the base of the sixth transistor 168. The emitter of the sixth transistor 168 is connected to the tenth resistor 170.
Is connected to the other input terminal of the operational amplifier 154. The emitter of the sixth transistor 168 is directly connected to the ground line.

The base of the fifth transistor 164 is connected to the 5v output terminal of the power supply 100 via the eleventh resistor 172 and to the ground line via the twelfth resistor 174, respectively. Further, the base of the sixth transistor 168 is connected to the base of the power supply 100 via the thirteenth resistor 176.
It is connected to the output terminal of v and to the ground line via the fourteenth resistor 178, respectively.

With such a configuration of the second regulation circuit 146, the A / D
The reference voltage V ₀ output to the reference voltage input terminal 136a of the converter 136 is calculated by the following formula.

Where R _V is the eighth, ninth, and tenth resistors 16
2, 166 and 170, which are resistance values defined by parallel resistance values of R ₈ , R ₉ , and R ₁₀ .

Here, the fifth and sixth transistors 164, 168
Are turned on when an "H" level signal is input and turned off when an "L" level signal is input. That is, when the "H" level signal is input to the third control signal input terminal 150a, the fifth transistor 164 is turned on, so that the resistance value R ₉ of the ninth resistor 166 becomes equal to the parallel resistance value R _V. It will contribute to the calculation. On the other hand, when the “L” level signal is input to the third control signal input terminal 150a, the fifth transistor 164 is turned off, and therefore the resistance value of the ninth resistor 166R ₉ is calculated as the parallel resistance value R _V. Will not contribute to.

Further, when the "H" level signal is input to the fourth control signal input terminal 150b, the sixth transistor 168 is turned on, so that the resistance value R ₁₀ of the tenth resistor 170 is equal to the parallel resistance value R _V. It will contribute to the calculation. On the other hand, when the "L" level signal is input to the fourth control signal input terminal 150b, the tenth transistor 170 is turned off, so that the resistance value R ₁₀ of the tenth resistor 170 is the parallel resistance value R _V.
Will not contribute to the calculation of.

In this way, the normal brightness is the brightness changeover switch 140.
When selected by the resistance value R _V it will be defined by the parallel resistance value of the resistance value R ₈ of the resistor 162 of the eighth and the resistance value R ₉ the ninth resistor 166. When a high brightness is selected, the resistance value R _V is equal to that of the eighth resistance 1
The resistance value is defined only by the resistance value R _{8 of} 62.
Furthermore, when low brightness is selected, the resistance value R _V is
It will be defined by the parallel resistance value of the resistance value R ₁₀ of the resistance value R ₈ and tenth resistor 170 of the eighth resistor 162.

By changing the lightness of the image by the lightness changeover switch 140 in this manner, the resistance value R _V changes, and accordingly,
The reference voltage V ₀ input to the reference voltage input terminal 136a of the A / D converter 136 also changes.

Here, the data output terminal 1 of the A / D converter 136
The value of the data output from 36b is defined by output data value = input voltage / reference voltage × full bit number. Therefore, when the reference voltage changes due to the switching of the brightness, the value of the output data also changes due to the switching of the brightness. In this way, by switching the lightness with the lightness changeover switch 140, the image quality of the image is improved regardless of the image quality of the original.

In the above-described embodiment, the image reading operation has been described for the case where the document has the color image surface. Here, when the original has a black-and-white image surface, the green filter G of the filter mechanism 36 is the switching mechanism 7.
By 4, the position can be switched so that it is located in the optical path of the reflected light. In this way, the black and white image of the original is scanned for reading through the green filter G.

As described in detail above, according to this one embodiment, various effects as described below can be achieved.

(1) First, a switching mechanism 74 for switching the position of the filter mechanism 36 is provided with a pair of cam grooves 84 and 86 formed in the filter frame 36a, and a pair of engaging members that are respectively engaged with the cam grooves 84 and 86. The retaining pawls 88, 90 and the protrusions 76a, 76b attached to the first and second side plates 14a, 14b so as to be able to contact the filter frame 36a are provided. The protrusions 76a and 76b are provided in the home position area H. In this way, the filter switching and resetting operations are performed in the home position area H. Therefore, the switching operation of the filter is performed regardless of the reading area N, and the reading area can be set wide.

Further, the switching mechanism 74 does not have a driving source by itself, but uses the driving force of the pulse motor 62 which is a driving source of the carriage 20. In this way, the switching mechanism 74
The configuration is simplified, and its control is facilitated.

Further, even when the driving of the image reading device 10 is stopped in a state where any of the filters is located in the optical path of the reflected light,
As the driving of the image reading device 10 is restarted, the carriage 20 is moved along the direction opposite to the image scanning direction X until the reset switch 72 is turned on, whereby the filter mechanism 36 automatically returns to the initial state. Will be done. That is, as the power is turned on, the filter mechanism 36
The blue filter B is automatically positioned in the optical path of the reflected light. In this way, since the return operation of the carriage 20 and the return operation of the filter mechanism 36 are performed at the same time, there is no useless operation between them and the time until the start of reading is shortened.

(2) Next, in this embodiment, the carriage 20
The first and second guide rollers 40a and 40b which are in rolling contact with the first rail 16a, and the movable guide roller 46 which is in rolling contact with the second rail 16b are provided as the supporting mechanism. Here, the first and second guide rollers 40a and 40b are mounted with their positions fixed, while the movable guide roller 46 is mounted so that their positions are movable. In addition, the movable guide roller 46
Is urged by a torsion spring 48 so as to be pressed against the second rail 16b. In this way, since the carriage 20 is always elastically supported, rattling of the carriage 20 during traveling of the carriage 20 is prevented even if the parallelism of the rails 16a and 16b is slightly different. Will be.

Further, the stopper member 22b of the carriage body 22 restricts the rotation of the lever member 24, so that the inclination of the carriage 20 is prevented. Therefore, the photoelectric converter 34 can be accurately read without tilting with respect to the reading scanning direction or vibrating during reading, and a good reproduced image without distortion or blurring in the reproduced image can be provided. become.

(3) Also, in this embodiment, the carriage 20
Every time the image is moved from the home position area H to the image reading area N, that is, every time when the image of each color of the original is read, the reading start position O separated from the fixed reading reference position O ₁ by a predetermined distance. ₂ is prescribed. In this way, even if the position shift of the carriage 20 occurs during the reading / scanning operation of the carriage 20, the shift is prevented from affecting the next reading operation. That is, since the reading start position O ₂ for each color is set with respect to the fixed reading reference position O ₁ , the position of the image for each color is constantly corrected, and therefore the deviation for each color is prevented. A good image will be provided.

Here, since the reading start position O ₂ is optically detected, the position is defined extremely accurately. Further, as an optical detection device for the reading start position O ₂ , a dedicated detection device is not separately provided, but a photoelectric converter 34 for image reading is used. In this way, it is not necessary to increase the number of parts in order to define the reading start position O ₂ , and the structure is simplified.

(4) In this embodiment, in order to detect the read reference position O ₁ , the position where the detection result changes from the white band Wh of the reference position setting member 70 to the black band Bl in the photoelectric converter 34. Has been detected. Here, the change in the detection position from the white band portion Wh to the black band portion Bl is defined when the detection level reaches 1/4 of the full scale of the input level of the A / D converter 136. That is, since the reference point of the detection operation for detecting the black band Bl is defined by 1/2 ² of the full scale, A / D
The output of the converter 136 is directly used as the detection result. Further, even if the white level drops due to the shading characteristics, the detection result is not affected, and the black setting does not have to be true black.

The photoelectric converter 34 also includes 862 photocells. In this embodiment, the photoelectric converter 34 detects the black level by detecting that one photo sensor has reached the black level or by detecting that all the photo sensors have reached the black level. Is not detected, but the photoelectric converter 34 recognizes that the black level is detected when the 64 photosensors detect the black level. In this way, even if 1
If dust adheres to each photo sensor, 1
Even if one photosensor wrongly detects a black level or one photosensor wrongly detects a white level due to some reflection, the position is accurately detected without being affected by such an error. Detection will be done.

In this detection, 64 photoelectric sensors, that is, 2 ⁿ photosensors detect the black level, and the photoelectric converter 34 recognizes that the black level is detected. Therefore, it suffices to count the number of photosensors that have detected the black level with a counter and detect an overflow in this counter. In this way, the photoelectric converter 34 can detect the black level very easily.

Furthermore, while the photoelectric converter 34 is detecting the white band portion Wh, shading correction can be performed, and it is not necessary to separately provide a white member for this shading, and the configuration is simplified. .

(5) In this embodiment, the filters are switched so as to be selectively positioned in the optical path of the reflected light so that the color image of the original is read. Here, both halogen lamps 28a and 28b correspond to the color of each filter so that even if each filter is switched, the output level of the photoelectric converter 34 does not change and a constant output level can be maintained. The applied voltage is applied.
In this way, the correction for preventing the output levels from being different due to the different colors of the filters can be very easily performed by only the electrical processing.

Further, since it becomes possible to detect the optimum linear change area of the photoelectric converter 34 for each filter, the gradation accuracy of the image is significantly improved.

(6) Finally, in this embodiment, the brightness is adjusted, that is, the brightness can be switched in order to improve the image quality. The switching of the brightness is executed by pressing the brightness switching switch 140 provided on the panel board 138. When the switch 140 is pushed, the reference input voltage of the A / D converter 136 is changed, and the output data from this is changed according to the switched brightness. In this way, the resistance value is changed in an analog manner in order to change the reference voltage. In this way, the brightness can be switched very easily. Also, the output level from the A / D converter 136 can be changed not in a digital manner but in an analog manner.

Further, since the switching of the lightness can be performed without changing the level of the video signal, the S / N ratio of the entire system can be kept good. In addition, protection for the A / D converter 136 is also realized.

The various effects detailed above are achieved by the configuration of an embodiment of the image reading apparatus according to the present invention. However, it goes without saying that the configuration of the image reading apparatus of the present invention is not limited to the configuration of this embodiment and can be variously modified without departing from the scope of the present invention.

For example, in the above-described embodiment, the filter switching mechanism 74 is provided with the first and second protrusions 84c and 84d on the bottom surface of the cam groove 84 (86), and the spring 96 is provided with the locking claw 8.
8 (90) has been described as being biased downwardly and laterally.
However, the present invention is not limited to such a configuration, and for example, as shown as a modified example in FIG. 14, the corresponding side plate 14 of the straight groove portion 84a of the cam groove 84 (86).
The first and second protrusions 84 are provided on the side wall on the a (14b) side.
c and 84d, corresponding to the first and second locking grooves 180
Alternatively, a and 180b may be formed.

Here, each locking groove 180a, 180b has an upright surface that is upright with respect to the side surface and an inclined surface that is inclined. The upright surface of the first locking groove 180a is defined as the green filter setting surface S _G , and the upright surface of the second locking groove 180b is defined as the red filter setting surface S _R.

As described above, by constructing the modification of the switching mechanism 74 of the filter mechanism 36, it is possible to obtain the same effect as that of the above-described embodiment. Further, in this modified example, the structure of the spring 96 suffices to urge the locking claw 88 only toward the side plate 14a, and a unique effect that the structure is simplified can be obtained. It will be.

Further, in the above-described embodiment, the filter mechanism 36
As a biasing means for biasing the filter frame 36a in the direction opposite to the image scanning direction X.
Although a and 82b have been described, the present invention is not limited to such a configuration and may be configured by a leaf spring, for example. Also, as the operating member,
Although the above-described embodiment has been described as including the protruding member, it may be separately provided with a hook portion that is attached to the carriage and can engage with a groove formed in the side plate portion, or with a permanent magnet. You may do it.

Further, in the above-described embodiment, when reading a black-and-white original document, the reflected light from the original document is guided to the photoelectric converter 34 via the green filter G.
The present invention is not limited to such a configuration. For example, when the filter mechanism 36 is provided with a transparent filter in addition to the blue filter B, the green filter G, and the red filter R, and a black-and-white original is read. The switching mechanism 7
The transparent filter may be located in the optical path of the reflected light via the optical path 4.

Further, in the above-described embodiment, in order to define the reading reference position O ₁ , the position where the detection target portion by the photoelectric converter 34 moves from the white belt portion Wh of the reference position setting member 70 to the black belt portion Bl. Are using. However, the present invention is not limited to such a configuration, and for example, the time when the detected portion moves from the black belt portion Bl to the white belt portion Wh may be defined as the read reference position O _1. good.

Further, in the above-described embodiment, the filter mechanism 36 is used.
Although it has been described that the first restriction circuit 102 is provided in order to prevent the output level of the photoelectric converter 34 from changing in accordance with the switching operation of the filters B, G, and R in FIG.
The present invention is not limited to such a configuration. For example, the configuration of the first regulation circuit is not limited to the configuration shown in FIG. 11, and the halogen lamps 28a and 28b are controlled according to the control signal from the control circuit. Any structure may be used as long as it can change the voltage applied to it.

Furthermore, in the above-described embodiment, the lightness is switched by pressing the lightness changeover switch 140 so that a control signal corresponding to the lightness set by the control unit 142 is output. Without being limited to such a configuration, for example, by configuring the brightness changeover switch from a volume and rotating this volume,
The reference voltage to the A / D converter 136 may be directly changed in an analog manner.

[Effects of the Invention] As described in detail above, the image reading apparatus according to the present invention includes an image reading area and a home position area provided adjacent to the image reading area, and a plurality of color images of an original are classified by color. An image reading device that reads and scans separately in each time, a carriage movably provided in the reading scanning direction, and a carriage that scans the carriage in the image reading region and the home position region along the scanning direction. A drive mechanism for moving the reading area to return to the home position area in a direction opposite to the scanning direction after scanning is completed, and a position provided in the home position area for starting scanning of the image reading area. And a reference position setting member having a detection surface, and a document mounted on the image reading area attached to the carriage. A photoelectric converter having a plurality of photoelectric conversion elements that optically read an image and optically read the detection surface of the reference position setting member, and a predetermined photoelectric conversion element of the photoelectric conversion elements that read the detection surface of the reference position setting member. The number of photoelectric conversion elements that have reached the level is counted, and the time when the count reaches a predetermined number is defined as a read reference position, and the image reading start position by the photoelectric converter is predetermined with respect to the read reference position. It is characterized in that it is provided with a judging means for setting the distance to the downstream side along the scanning direction. Therefore, according to the present invention, the reading reference position for setting the reading start position of the image can be set extremely accurately, and an image reading device capable of reproducing a good color image without color misregistration is provided. Will be done.

[Brief description of drawings]

1 is a plan sectional view showing the construction of an embodiment of an image reading apparatus according to the present invention, FIG. 2 is a side sectional view showing the construction of the image reading apparatus shown in FIG. 1, and FIG. 3 is a construction of a carriage. FIG. 4 is a front view showing the structure of the carriage main body, FIG. 5 is a side view showing the structure of the carriage, FIG. 6 is a side view showing the structure of the reading reference member, and FIG. FIG. 8 is a plan view of a carriage for explaining the structure of the switching mechanism, FIG. 8 is a perspective view showing the structure of a cam groove, FIG. 9 is a side sectional view showing a mounting state of a locking lever, and FIG. 10 is a photoelectric converter. FIG. 11 is a side sectional view showing a reading start state of the scanning reference member according to FIG. 11, FIG. 11 is a circuit diagram showing a configuration of a first regulation circuit, FIG. 12 is a block diagram showing a brightness switching system, and FIG. 13 is a second regulation. FIG. 14 is a circuit diagram showing a circuit configuration, and FIG. 14 is a cam. It is a perspective view which shows the modification of a groove. 10 ... Image reading device, 20 ... Carriage, 34 ...
Photoelectric converter (reading means, detector), 50 ... Driving mechanism, 70 ... Reference position setting member, Bl ... Black band (second color surface), HP ... Home position area, N ... Image Reading area, Wh ... White band (first color surface).

Front Page Continuation (72) Inventor Mochizuki Ni Yamanashicho 3167, Kofu City, Yamanashi Pref., Japan Precision Industry Co., Ltd. (72) Inventor Mineo Kubota 3167 Yamamiyacho, Kofu City, Yamanashi Pref.

Claims (2)

[Claims] 1. An image reading apparatus, comprising an image reading area and a home position area provided adjacent to the image reading area, for reading and scanning a color image of an original in plural times for each color. A carriage movably provided along the scanning direction, and scanning the carriage along the scanning direction in the image reading area and the home position area. A drive mechanism that moves so as to return in the opposite direction, a reference position setting member that is provided in the home position area and has a detection surface that defines a position to start scanning of the image reading area, and is attached to the carriage. , The image of the document placed in the image reading area is optically read, and the reference position setting member is detected. A photoelectric converter having a plurality of photoelectric conversion elements that optically reads the output surface, and counts the number of photoelectric conversion elements that have reached a predetermined level among the photoelectric conversion elements that read the detection surface of the reference position setting member, and the counted number. Is defined as a read reference position, and a determination means for setting the image reading start position by the photoelectric converter downstream of the read reference position by a predetermined distance in the scanning direction. An image reading apparatus comprising: 2. The detection surface of the reference position setting member includes a white first surface and a black second surface that are adjacent to each other in the scanning direction, and the detection surface of the reference position setting member is characterized in that: Image reading device.