JP2002354206A - Document reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize constitution requiring no adjustment with respect to a document reader which moves carrier, on which a line image sensor is mounted, in the subscanning direction to read a document placed on a document placing table. SOLUTION: The document reader is provided with an adjustment hole which is formed in a unit, to which the document placing table is attached, and has edge parts parallel with the main scanning direction and the subscanning direction, a detection means which detects the edge parts of the adjustment hole from image data of the adjustment hole read by the line image sensor, and a correction means which corrects not only the preset document read start pixel position in the main scanning direction but also the preset document read start position in the subscanning direction in accordance with positions of the edge parts detected by the detection means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading apparatus for reading a document placed on a document table by moving a carrier on which a line image sensor is mounted in a sub-scanning direction. The present invention relates to a document reading device to be realized.

A document reading apparatus that reads a document placed on a document table by moving a carrier on which a line image sensor is mounted in the sub-scanning direction has become widespread. In order to increase the productivity of the document reading device, it is necessary to construct a configuration without adjustment.

[0003]

2. Description of the Related Art In a document reading apparatus for reading a document placed on a document table by moving a carrier on which a line image sensor is mounted in a sub-scanning direction, a home position for setting the carrier at its home position is provided. It has a configuration with a sensor.

At the time of factory shipment or maintenance, the movement distance of the carrier from the home position detected by the home position sensor to the document table is actually measured.
When actually reading the original, the reading of the original is started with the position shifted by the actually measured distance from the home position detected by the home position sensor as the reading start position of the original.

Further, at the time of factory shipment or maintenance, the pixel position of the line image sensor corresponding to the side of the original platen which is the main scanning start side is obtained by actual measurement, and when the original is actually read, this is obtained by this actual measurement. The reading of the document is started from the pixel position.

[0006]

As described above, in the prior art, in order to determine the reading start position in the sub-scanning direction, at the time of factory shipment or maintenance, the document table is detected from the home position detected by the home position sensor. The movement distance of the carrier is measured, and the reading start position in the sub-scanning direction is determined accordingly.

[0007] Such adjustment is required because, due to the mounting error of the home position sensor, the carrier moving distance from the home position to the document table cannot be determined at the time of design. .

Further, in the prior art, in order to determine the pixel position to start reading in the main scanning direction, it is necessary to carry out the
The pixel position of the line image sensor corresponding to the side of the document table on the main scanning start side is obtained by actual measurement, and the read start pixel position in the main scanning direction is adjusted accordingly.

[0009] Such adjustment is required because of the mounting error of the line image sensor, the pixel position of the line image sensor corresponding to the side of the original platen which is the main scanning start side is determined at design time. Is not possible.

As described above, according to the prior art, there is a problem that adjustment is required at the time of shipment from the factory or at the time of maintenance, and thus the productivity of the document reading apparatus cannot be improved.

The present invention has been made in view of such circumstances, and has a configuration in which a carrier on which a line image sensor is mounted is moved in a sub-scanning direction to read a document placed on a document table. Accordingly, it is an object of the present invention to provide a new document reading apparatus that realizes a configuration without adjustment.

[0012]

In order to achieve this object, in the document reading apparatus of the present invention, the carrier on which the line image sensor is mounted is moved in the sub-scanning direction.
When adopting a configuration of reading a document placed on a platen, there is a “adjustment hole (even if it penetrates) that is formed in a unit to which the platen is attached and has an edge portion parallel to the main scanning direction. Or just a depression) "," detection means "for detecting an edge portion of the adjustment hole from image data of the adjustment hole read by the line image sensor, and an edge for detection by the detection means. A "correction unit" for correcting a document reading start position in the sub-scanning direction set in advance in accordance with the position of the portion is provided.

When configured as described above, the original reading apparatus of the present invention may be provided with two adjustment holes on the scanning start side and the scanning end side in the main scanning direction.
The correction unit calculates an intermediate value between the positions of the edge portions of the two adjustment holes detected by the detection unit, and corrects the document reading start position in the sub-scanning direction according to the calculated value.

When configured as described above, in the document reading apparatus of the present invention, an adjustment hole may be provided between the home position of the carrier and the document reading start position in the sub-scanning direction. In some cases, the detecting unit detects an edge portion of the adjustment hole while the carrier is moving from the home position to the document reading start position in the sub-scanning direction.

In the document reading apparatus of the present invention configured as described above, an adjustment hole having an edge portion parallel to the main scanning direction is provided in the unit for mounting the document table.

Since the adjusting hole is formed in the unit on which the document table is mounted, the distance between the edge portion of the adjustment hole and the document table is as designed.

Accordingly, for example, when the adjustment hole is provided between the home position of the carrier and the document reading start position in the sub-scanning direction, the distance from the home position detected by the home position sensor to the edge portion thereof. Is not as designed, due to the mounting error of the home position sensor.
The distance from the edge to the document table is as designed.

From the above, for example, according to the design value, the adjusting means has an edge portion of the adjusting hole at a position shifted by 50 pulses from the home position detected by the home position sensor, and further shifts the position by 50 pulses from the home position detected by the home position sensor. When there is a platen in
If it is detected that there is an edge portion of the adjustment hole at a position shifted by 52 pulses from the home position position detected by the home position sensor, a position shifted by 100 pulses from the home position position according to the design value. The reading of the document is started from the position. In practice, the reading of the document is corrected to start from a position shifted by 102 pulses from the home position.

As described above, according to the document reading apparatus of the present invention, reading in the sub-scanning direction can be started from an accurate position of the document table without adjustment at the time of factory shipment or maintenance.

According to another aspect of the present invention, there is provided a document reading apparatus for reading a document placed on a document table by moving a carrier mounting a line image sensor in a sub-scanning direction. Is used, the adjustment hole (which may be penetrated or may be simply recessed) is formed on the unit for attaching the document table and has an edge portion parallel to the sub-scanning direction. When,
"Detection means" for detecting an edge portion of the adjustment hole from image data of the adjustment hole read by the line image sensor, and a main scanning direction set in advance according to the position of the edge portion detected by the detection means. And a “correction unit” that corrects the original reading start pixel position.

With this configuration, the original reading apparatus of the present invention may have an adjusting hole between the home position of the carrier and the original reading start position in the sub-scanning direction. The detection means detects an edge portion of the adjustment hole while the carrier is moving from the home position to the document reading start position in the sub-scanning direction.

In the document reading apparatus of the present invention configured as described above, an adjustment hole having an edge portion parallel to the sub-scanning direction is formed on the unit on which the document table is mounted.

Since the adjusting hole is formed in the unit on which the document table is mounted, the distance between the edge portion of the adjustment hole and the document table is as designed.

Therefore, the pixel position of the line image sensor corresponding to the side of the platen is not as designed according to the mounting error of the line image sensor. The distance to is as designed.

From this, the correction means is used, for example, when the edge of the adjustment hole is located at the tenth pixel position of the line image sensor and the document table is located five pixels further from the tenth pixel position in the design value. When the detecting means detects that the edge portion of the adjustment hole is located at the twelfth pixel position of the line image sensor, the original is read from the fifteenth pixel position of the line image sensor according to the design value. Is actually corrected so as to start reading the document from the 17th pixel position of the line image sensor.

As described above, according to the document reading apparatus of the present invention, reading in the main scanning direction can be started from an accurate position of the document table without adjustment at the time of factory shipment or maintenance.

As described above, according to the document reading apparatus of the present invention, a document placed on a document table can be read accurately without adjustment at the time of factory shipment or maintenance.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail according to embodiments.

FIG. 1 shows an embodiment of an original reading apparatus according to the present invention.

The original reading apparatus of the present invention according to this embodiment is placed on an original table 3 made of glass by moving a carrier 2 on which a CCD type line image sensor 1 is mounted in the sub-scanning direction. When reading a document to be read, a rectangular reference hole 5 having an edge portion parallel to the main scanning direction and the sub-scanning direction is provided in the housing unit 4 prepared for mounting the document table 3. It has a configuration that includes. Here, it is preferable that the reference hole 5 penetrates, but the reference hole 5 may be only a depression.

According to this embodiment, the reference hole 5 is
The main scanning start side edge portion (hereinafter referred to as “main scanning reference position”) which is provided at the main scanning start side position before the platen 3 and is parallel to the sub-scanning direction of the platen 3 and the main scanning of the platen 3 It is provided at a position in a positional relationship where the side is on a straight line.

Here, reference numeral 6 denotes a document holder for pressing a document placed on the document table 3, and reference numeral 7 denotes a carrier for setting the carrier 2 at its home position.
It is a home position sensor.

FIG. 2 shows a circuit configuration of a hardware circuit provided in the original reading apparatus of the present invention.

As shown in this figure, the original reading apparatus equipped with the present invention amplifies the image data output from the CCD line image sensor 1 similarly to the conventional original reading apparatus in terms of the hardware circuit configuration. An A / D converter 10 for A / D conversion, an image control LSI 11 for performing image processing such as shading correction using image data output from the A / D converter 10 as input, and white reference data required for shading correction And black / white storage data 12, a memory 13 for storing image data output from the image control LSI 11, an interface LSI 14 for externally outputting image data stored in the memory 13, and a carrier 2. A motor 15 to be moved; a motor driver 16 to control the movement of the carrier 2 by controlling the motor 15; 17, a CPU 18, and a power supply 19.

The EPROM 17 stores information on a document reading start position determined at the time of design, information on a position surrounding the reference hole 5 determined at the time of design (a line number range from the home position, and a pixel position in the main scanning direction). Represented by a range).

As shown in FIG. 3, an edge portion on the main scanning start side which is parallel to the sub-scanning direction of the reference hole 5 is referred to as a “main scanning reference position”, and is parallel to the main scanning direction of the reference hole 5. The home position side edge portion is referred to as a “sub-scanning reference position”, and is represented by the number “x” of motor drive pulses required to move the carrier 2 from the home position position to the “sub-scanning reference position”. If the number of motor drive pulses “y” required to move the carrier 2 from the position to the document reading start position is represented by the EPROM 17
Is the number of motor drive pulses “(y−x) + x” as information of the document reading start position in the sub-scanning direction determined at the time of design.
Is stored.

On the other hand, the EPROM 17 stores information on the original reading start pixel position in the main scanning direction determined at the time of design.
The pixel position “z” of the line image sensor 2 associated with the “main scanning reference position” is stored.

Since the reference hole 5 is formed in the housing unit 4 prepared for mounting the document table 3, the positional relationship between the reference hole 5 and the document table 3 is as designed. It has become something.

Accordingly, the number of motor drive pulses “y−x” required to move the carrier 2 from the “sub-scanning reference position” to the document reading start position is as designed, The “scanning reference position” has a positional relationship on a straight line with the side of the original table 3 on the main scanning start side, as designed.

FIGS. 4 and 5 show an embodiment of a processing flow executed when the document reading apparatus of the present invention reads a document placed on the document table 3. FIG.

Next, a document reading process executed by the document reading apparatus of the present invention according to this processing flow will be described in detail. Here, this processing flow is executed by the CPU 18.
It is executed by a document reading program running on the above.

When an original reading request for an original placed on the original platen 3 is issued, the original reading program starts with step 1 in the sub-scanning direction as shown in the processing flow of FIGS. The movement of the carrier 2 is started.

Subsequently, in step 2, it is determined whether or not the reading start position of the reference hole 5 specified by the position information of the reference hole 5 stored in the EPROM 17 has been reached. Then, the process proceeds to step 3, and input of image data of the reference hole 5 is started according to the position information.

Subsequently, in step 4, the "main scanning reference position" and the "sub-scanning reference position" shown in FIG. 3 are detected in accordance with the input image data of the reference hole 5, thereby obtaining the "main scanning reference position". Line image sensor 1 associated with
And the number of motor drive pulses required to move the carrier 2 from the home position position to the “sub-scanning reference position” are detected.

The detection processing of the "main scanning reference position" and the "sub-scanning reference position" is executed according to the processing flow shown in FIG.

That is, when the document reading program starts the detection processing of the "main scanning reference position" and the "sub-scanning reference position", as shown in the processing flow of FIG. One line of image data of the hole 5 is input.

Subsequently, at step 41, the input image data is integrated in the main scanning direction, and the integrated value is calculated as 1st.
By dividing by the number of pixels of the line (corresponding to the length of the reference hole 5), the average value of the pixel values in the main scanning direction is calculated.
That is, as shown in FIG. 7, an average value of pixel values is calculated in the main scanning direction.

Subsequently, at step 42, the EPROM 17
Hole 5 specified by position information of reference hole 5 stored in
It is determined whether or not the reading end position has been reached. If it is determined that the reading end position has not been reached, the process proceeds to step 43, where the next one line of the image data of the reference hole 5 is input.

Subsequently, at step 44, the average value of the previously calculated image data is multiplied by the number of lines used for calculating the average value, and the multiplied image data and the currently input image data are processed in the sub-scanning direction. Then, by dividing the total value by the number of lines obtained by incrementing the number of lines by 1, the average value of the current pixel values in the sub-scanning direction is calculated.

That is, when the average value is calculated for the first time this time, as shown in FIG. 8, the image data input in the first time and the image data input in the second time are summed in the sub-scanning direction. Is divided by the number of lines "2" to calculate the average value of the pixel values in the sub-scanning direction.
When the second average value is calculated, as shown in FIG. 8, the first average value is multiplied by the number of lines “2” used in the calculation of the average value, and the image data is multiplied. By summing the image data input this time in the sub-scanning direction and dividing the total value by the number of lines “3”, the average value of the pixel values in the sub-scanning direction is calculated.

Subsequently, in step 45, the input image data is integrated in the main scanning direction, and the integrated value is divided by the number of pixels of one line (corresponding to the length of the reference hole 5). After calculating the average value of the pixel values in the main scanning direction,
Return to step 42. That is, as shown in FIG. 7, the process returns to step 42 after calculating the average value of the pixel values in the main scanning direction.

On the other hand, when it is determined in step 42 that the reading end position of the reference hole 5 has been reached, step 4
Then, the process proceeds to step S6, where the primary differential processing is performed on the average pixel value in the main scanning direction obtained in the form shown in FIG. That is,
The primary differentiation process is performed as shown in FIG.

Subsequently, at step 47, the above-mentioned "main scanning reference position" is detected in accordance with the edge portion of the reference hole 5 specified by the processing result of the primary differentiation processing (the location where the primary differentiation shows the maximum value). In a succeeding step 48, the pixel position of the line image sensor 1 corresponding to the "main scanning reference position" is detected.

Subsequently, in step 49, a primary differentiation process is performed on the pixel average value in the sub-scanning direction obtained in the form shown in FIG. That is, the primary differential processing is performed as shown in FIG.

Subsequently, in step 50, the above-mentioned "sub-scanning reference position" is detected according to the edge portion of the reference hole 5 specified by the processing result of the first-order differentiation processing (the point where the first-order differentiation shows the maximum value). In a succeeding step 51, the number of motor drive pulses (corresponding to the motor drive pulse number "x" shown in FIG. 3) required for moving the carrier 2 from the home position position to the "sub-scanning reference position" is detected. I do.

Thus, the original reading program is:
According to the processing of step 4 in the processing flow of FIG. 4, when the detection processing of the “main scanning reference position” and the “sub-scanning reference position” is started, the processing flow of FIG. By detecting the “main scanning reference position” and the “sub-scanning reference position”, the pixel position of the line image sensor 1 associated with the “main scanning reference position” and the home position position to the “sub-scanning reference position” Carrier 2
The number of motor drive pulses required for the movement of the motor is detected.

According to the processing in step 4 of the processing flow of FIG. 4, the original reading program executes the processing from the pixel position of the line image sensor 1 associated with the "main scanning reference position" and the home position position to the "sub-scanning reference position". When the number of motor drive pulses required for moving the carrier 2 is detected, subsequently, in step 5, the number is set in advance according to the pixel position of the line image sensor 1 associated with the detected “main scanning reference position”. The read start pixel position in the main scanning direction is corrected.

That is, the pixel position "z" of the line image sensor 2 associated with the "main scanning reference position" is stored in the EPROM 17 as information on the document reading start pixel position in the main scanning direction. Due to the mounting error of the image sensor 1, there is a possibility that the stored pixel position "z" may not be as designed.
By correcting the stored pixel position “z” to the pixel position “z ′” of the line image sensor 1 detected from the reference hole 5, the preset reading start pixel position in the main scanning direction is corrected. is there.

Subsequently, in step 6, the reading end pixel position "z '+ Z" in the main scanning direction is determined according to the size of the document to be read set by the user.

Subsequently, in step 7, according to the number of motor drive pulses required to move the carrier 2 from the home position position detected in step 4 to the "sub-scanning reference position", the predetermined number in the sub-scanning direction is set. Correct the reading start position.

That is, the EPROM 17 stores, as information of the document reading start position in the sub-scanning direction, the number of motor drive pulses "(") required to move the carrier 2 from the home position to the document table 3 at the document reading start position. y-
x) + x "is stored, but the motor drive pulse number" x "may not be as designed according to the mounting error of the carrier home position sensor 7. Therefore, the motor drive pulse number" x "is stored. By correcting “x” to the number of motor drive pulses “x ′” detected from the reference hole 5, the stored number of motor drive pulses “(y−x) +
By correcting “x” to “(y−x) + x ′” detected from the reference hole 5, a preset reading start position in the sub-scanning direction is corrected.

Here, as described above, the number of motor drive pulses "y-x" required to move the carrier 2 from the "sub-scanning reference position" to the side position of the document table 3 which is the document reading start position. Is the same as the design value, so there is no need to correct it.

Subsequently, in step 8, the reading end position "(yx) + x '+ X" in the sub-scanning direction is determined according to the size of the document to be read set by the user.

Subsequently, in step 9, waiting for the carrier 2 to arrive at the reading start position “(y−x) + x ′” in the sub-scanning direction corrected in step 7, it is determined that the carrier 2 has arrived. Proceeding to 10, the reading start pixel position "z '" in the main scanning direction corrected in step 5 and step 6
Read end pixel position “z ′ + Z” in the main scanning direction determined in
The image data of the original placed on the original platen 3 is input in accordance with the following. In the following step 11, the carrier 2 is located at the reading end position “(y−x) + x ′ + X” in the sub-scanning direction determined in step 8. Until the image data is reached, the input of the image data is executed.

As described above, in the document reading apparatus provided with the present invention, the document placed on the document table 3 can be read accurately without any adjustment at the time of factory shipment or maintenance.

FIG. 10 shows another embodiment of the document reading apparatus of the present invention.

This embodiment employs a configuration having two reference holes, a first reference hole 5a provided at the main scanning start position and a second reference hole 5b provided at the main scanning end position. I have.

In accordance with this embodiment, the document reading program replaces the processing flow of FIGS.
And the processing flow of FIG.

The difference between the processing flows of FIGS. 11 and 12 and the processing flows of FIGS. 4 and 5 will be described. In the case of following the processing flows of FIGS. When detecting the pixel position of the line image sensor 1 associated with the "main scanning reference position" and the number of motor drive pulses required to move the carrier 2 from the home position position to the "sub-scanning reference position" In response to the provision of the two reference holes, the first reference hole 5a and the second reference hole 5b, two motor drive pulse numbers are detected.

From now on, when the processing flow of FIGS. 11 and 15 is followed, the processing of “step 4” corresponding to step 4 of the processing flow of FIGS. 4 and 5 and the processing flow of FIG. 4 and FIG. The carrier from the home position position to the “sub-scanning reference position” is interposed between the process of “Step 5” associated with Step 5 and the intermediate value of the two motor drive pulse numbers detected in the process of “Step 4”. In this configuration, a “step α” for performing a process of detecting the final number of motor drive pulses required for the movement of No. 2 is adopted.

Here, the process of detecting the pixel position of the line image sensor 1 associated with the "main scanning reference position" is executed using the first reference hole 5a provided on the main scanning start side. Become.

According to the embodiment of FIG. 10, the number of motor drive pulses required for moving the carrier 2 from the home position position to the "sub-scanning reference position" is detected using two reference holes. Therefore, the document can be read with higher accuracy as compared with the embodiment of FIG. 1 described above.

In the above-described embodiment, both the original reading start pixel position in the main scanning direction and the original reading start position in the sub-scanning direction are corrected using the reference hole 5 so that complete adjustment is possible. However, by applying the present invention only to the document reading start pixel position in the main scanning direction, a configuration without adjustment is realized, and the document reading start position in the sub scanning direction is adjusted as in the related art. Or
Alternatively, by applying the present invention only to the document reading start position in the sub-scanning direction, a configuration without adjustment may be realized, and the document reading start pixel position in the main scanning direction may be adjusted as in the related art.

[0074]

As described above, according to the present invention,
By adopting a configuration in which the carrier on which the line image sensor is mounted is moved in the sub-scanning direction to read the original placed on the platen, accurate adjustments are not required at the time of factory shipment, etc. Document reading can be realized.

According to the present invention, it is possible to improve the productivity of a document reading apparatus having a configuration for reading a document placed on a document table by moving a carrier on which a line image sensor is mounted in the sub-scanning direction. Become like

[Brief description of the drawings]

FIG. 1 is an embodiment of an original reading apparatus according to the present invention.

FIG. 2 is a circuit configuration diagram of a hardware circuit included in the document reading apparatus of the present invention.

FIG. 3 is an explanatory diagram of a main scanning reference position / sub-scanning reference position.

FIG. 4 is an embodiment of a processing flow executed by the document reading apparatus of the present invention.

FIG. 5 is an embodiment of a processing flow executed by the document reading apparatus of the present invention.

FIG. 6 is an embodiment of a processing flow executed by the document reading apparatus of the present invention.

FIG. 7 is an explanatory diagram of a process executed by the document reading apparatus of the present invention.

FIG. 8 is an explanatory diagram of a process executed by the document reading apparatus of the present invention.

FIG. 9 is an explanatory diagram of a main scanning reference position / sub-scanning reference position detection process.

FIG. 10 shows another embodiment of the document reading apparatus of the present invention.

FIG. 11 is another embodiment of the processing flow executed by the document reading apparatus of the present invention.

FIG. 12 is another embodiment of the processing flow executed by the document reading apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Line image sensor 2 Carrier 3 Document table 4 Housing unit 5 Reference hole 6 Document holder 7 Carrier home position sensor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B047 AA01 BA02 BB02 BC16 BC23 CA12 CB09 CB17 CB23 DB01 5C072 AA01 BA20 EA05 FB23 FB27 LA03 LA14 MB04 MB08 MB09 RA04 UA06

Claims (5)

[Claims] 1. A document reading apparatus for reading a document placed on a document table by moving a carrier on which a line image sensor is mounted in a sub-scanning direction. An adjustment hole having an edge portion parallel to the detection portion; a detection means for detecting the edge portion from the image data of the adjustment hole read by the line image sensor; and a position corresponding to the edge portion detected by the detection portion. A document reading device that corrects a document reading start position in a sub-scanning direction that is set in advance. 2. A document reading apparatus for reading a document placed on a document table by moving a carrier on which a line image sensor is mounted in a sub-scanning direction. An adjustment hole having an edge portion parallel to the detection portion; a detection means for detecting the edge portion from the image data of the adjustment hole read by the line image sensor; and a position corresponding to the edge portion detected by the detection portion. A document reading device that corrects a document reading start pixel position in a main scanning direction set in advance. 3. A document reading apparatus for reading a document placed on a document table by moving a carrier on which a line image sensor is mounted in a sub-scanning direction. An adjustment hole having an edge portion parallel to the sub-scanning direction; detection means for detecting the edge portion from image data of the adjustment hole read by a line image sensor; and an edge portion detected by the detection means. And correcting means for correcting a preset document reading start pixel position in the main scanning direction in accordance with the position, and correcting a preset document reading start position in the sub-scanning direction. Document reading device. 4. The document reading apparatus according to claim 1, wherein two of the adjustment holes are provided on a scanning start side and a scanning end side in a main scanning direction, and the correction means is provided. Is the above 2 detected by the detecting means.
A document reading device that calculates an intermediate value of the positions of the edge portions of the two adjustment holes and corrects the document reading start position in the sub-scanning direction according to the calculated value. 5. The document reading apparatus according to claim 1, wherein the adjustment hole is provided between a home position of the carrier and a document reading start position in a sub-scanning direction. A document reading apparatus, wherein the detecting means detects the edge portion while the carrier is moving from the home position to the document reading start position in the sub-scanning direction.