JP4308373B2 - Image reading apparatus and method for adjusting image reading apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reading apparatus such as a scanner used in a digital copying machine and a method for adjusting the image reading apparatus .
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image reading apparatus, an entire original is read by moving a carriage that scans and scans for each line in the main scanning direction of the original in the sub-scanning direction. The carriage of the image reading apparatus that moves in the sub-scanning direction accelerates to a predetermined reading speed corresponding to the reading magnification by a motor, and then moves at a constant speed at a predetermined reading speed to read a document.
[0003]
In the image reading apparatus, the reading magnification is changed by the carriage controlled as described above, and the moving speed at the time of image reading of the carriage is changed. In such an image reading apparatus, if a vibration generated when the carriage (CRG) is accelerated remains in an image area (reading area) that moves at a constant speed, the read image of the document is shaken.
[0004]
For example, when a line in the sub-scanning direction (carriage traveling direction) on the document (hereinafter referred to as a vertical line) is read, if the carriage vibrates in the reading area, the above line is not read in a straight line. It is read as a line swaying in the scanning direction.
[0005]
This is caused by the vibration generated when the carriage is started and the shift of the resonance point of the vibration generated when the carriage changes from the acceleration to the constant speed. Since the carriage performs zigzag movement due to such vibrations of the carriage, the optical system provided in the carriage swings to the left and right, and reading is performed as if the vertical lines are swaying.
[0006]
In particular, in a digital scanner that converts a read image into an electric signal for each pixel, vertical lines are also read by being subdivided into dot arrays, so that the read image is emphasized and read.
[0007]
For this reason, the vibration of the carriage should not be left when moving the image area where the original is actually read.
[0008]
As a countermeasure against such vibration of the carriage, it can be usually suppressed by first grasping where the carriage is swaying and making the swaying part a vibration-proof structure.
[0009]
However, since the anti-vibration measure on the structure of the carriage only shifts the resonance point of the carriage, there is a concern that vibration at some magnification will increase. In addition, providing the anti-vibration structure to the carriage leads to an increase in the weight of the carriage, leading to an increase in the manufacturing cost of the device such as a load on the drive system and a special specification for the motor used as the drive system. Become.
[0010]
There is also a method of making the acceleration during the acceleration of the carriage as gentle as possible. However, such a change in the acceleration of the carriage is not very effective, and there is a great possibility that it is nothing but a resonance point. In order to moderate the acceleration, a long distance is required for accelerating the carriage to a reading speed corresponding to a predetermined reading magnification, leading to an increase in the body of the image reading apparatus.
[0011]
Furthermore, extending the distance that the carriage moves at a constant speed from the end of acceleration to the reading area where the image is actually read is one of the means for suppressing vibration, but the distance that moves at the constant speed is also extended. This leads to an increase in the number of aircraft.
[0012]
There is also a method of setting a plurality of types of acceleration so that vibrations can be suppressed with respect to the carriage moving speed corresponding to all the reading magnifications when the carriage moving speed is in a wide range with various reading magnifications.
[0013]
However, the structure of the device always varies. For this reason, the vibration level of the carriage may deteriorate depending on the reading magnification among the accelerations set as described above. In this case, since the acceleration corresponding to the other reading magnification is optimized, it cannot be changed, and an airframe having a bad image shake at the above reading magnification occurs.
[0014]
In order to avoid carriage vibration at a specific reading magnification as described above, when the type of acceleration corresponding to the reading magnification is increased, it is necessary for a human to determine the carriage vibration level by visually observing an actual read image. . However, when judging the shaking of the image by visual observation, the number of manufacturing steps of the apparatus may increase, or it may become impossible to make a visual judgment on the reduced image. Further, if the read image is visually discriminated and set one by one as described above, it takes a lot of time and effort, and it cannot be realized as mass production of the apparatus.
[0015]
As described above, the conventional method has the following problems.
[0016]
(1) The anti-vibration structure of the carriage causes an increase in driving load, leading to an increase in cost.
[0017]
(2) Due to the structure of the image reading apparatus, variations occur for each machine. Therefore, even if a plurality of types of acceleration are set for the reading magnification, shaking may be deteriorated depending on the machine.
[0018]
(3) When the vibration level is determined visually from the read image, it becomes difficult to determine with a reduced image or the like, and the vibration level cannot be measured accurately. Moreover, it takes a lot of time and effort, and it cannot be realized as mass production.
[0019]
[Problems to be solved by the invention]
As described above, in order to suppress carriage vibration at the time of image reading that appears as a shake in the read image, it takes a lot of time for adjustment, leading to an increase in apparatus and cost. An object of the present invention is to provide an image reading apparatus and an adjustment method for the image reading apparatus that prevent the carriage from vibrating during image reading, suppress an increase in the number of devices and increase in cost, and do not require time and effort to adjust the carriage. Objective.
[0020]
[Means for Solving the Problems]
The image reading apparatus according to the present invention is provided below the document placing table on which the document is placed, and scans to read and scan one line of a plurality of pixels in the main scanning direction with respect to the document on the document placing table. The scanning unit is accelerated at any one of a plurality of types of acceleration from outside the document reading area in the sub-scanning direction of the document on the document table, and is moved at a constant speed corresponding to the reading magnification in the document reading area. Moving means for moving at a speed, reading means for moving the scanning means in the sub-scanning direction by the moving means and reading a reference document provided with at least one reference line placed on the document placing table; determination means for displacement of the read pixel with respect to a reference line on the reference document determines whether within a predetermined tolerance read by, tone adjusting the acceleration when accelerating the scanning means by said moving means A magnification setting unit for setting a target scanning magnification, and an acceleration when accelerating the scanning unit at the scanning magnification set by the magnification setting unit, the shift amount of the read pixel is determined to be within an allowable range by the determination unit. Select acceleration setting means to select and set the acceleration from the above-mentioned multiple types of acceleration, and control means to sequentially change the reading magnification set by the magnification setting means and repeatedly execute the processing by the acceleration setting means .
[0021]
According to the adjustment method of the image reading apparatus of the present invention, one line of a plurality of pixels in the main scanning direction is read and scanned with respect to the document on the document mounting table provided below the document mounting table on which the document is placed. Scanning means, and this scanning means is accelerated in the sub-scanning direction of the original on the original platen by any one of a plurality of types of acceleration from outside the original reading area, and corresponds to the reading magnification in the original reading area. An adjustment method used for an image reading apparatus having a moving means that moves at a constant moving speed, and sets a reading magnification of an adjustment target for adjusting an acceleration when the scanning means is accelerated by the moving means. Then, as an acceleration for accelerating the scanning means at the set reading magnification, one of the accelerations of the plurality of types is selected, and the scanning means is moved using the selected acceleration. The reference document provided with at least one reference line, which is moved in the sub-scanning direction by the means and placed on the document placing table, is read, and the deviation amount of the read pixel with respect to the reference line on the read reference document is predetermined. The acceleration determined that the deviation amount is within the allowable range by this determination is set in association with the reading magnification, the setting of the reading magnification is sequentially changed, and each reading magnification is set. The above selection, reading, determination, and setting processes are repeatedly executed.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0027]
FIG. 1 is a sectional view schematically showing an internal configuration of a scanner 10 as an image reading apparatus according to an embodiment of the present invention.
[0028]
As shown in FIG. 1, the scanner 10 includes an exposure lamp 14 as a light source for illuminating the document D placed on the document table 12, and a first mirror that deflects reflected light from the document D in a predetermined direction. 16 is attached to the first carriage 18 disposed below the document table 12.
[0029]
The first carriage 18 is disposed so as to be movable in parallel with the document placing table 12, and is reciprocated below the document placing table 12 by a drive motor 30 through a moving means such as a toothed belt (not shown). The drive motor 30 is composed of a pulse motor whose speed is controlled by a drive pulse signal or the like.
[0030]
A second carriage 20 that is movable in parallel with the document placing table 12 is disposed below the document placing table 12. Second and third mirrors 22 and 24 that sequentially deflect the reflected light from the document D deflected by the first mirror 16 are attached to the second carriage 20 at right angles to each other. The second carriage 20 is driven by the rotational force from the drive motor 30 by a toothed belt or the like that drives the first carriage 18, and is driven by the first carriage 18. On the other hand, it is moved in parallel along the document table 12 at a speed of 1/2.
[0031]
Further, below the document table 12, an imaging lens 26 that focuses the reflected light from the third mirror 24 on the second carriage 20 and the reflected light that is focused by the imaging lens 26 are received. A CCD sensor 28 for photoelectric conversion is provided. The imaging lens 26 is movably disposed in a plane including the optical axis of the light deflected by the third mirror 24 via a drive mechanism (not shown). An image is formed at a desired magnification. The CCD sensor 28 photoelectrically converts the incident reflected light for each pixel, and outputs an electrical signal corresponding to the read document D.
[0032]
The first carriage 18 starts to move from a predetermined standby position X and reads a document image from a document leading edge position Y when reading a document image on a document table.
[0033]
FIG. 2 is a block diagram schematically showing the drive system of the scanner 10 configured as described above.
[0034]
The scanner 10 includes a CPU 40 that controls the entire scanner, a RAM 41 for storing data, a ROM 42 that stores reading speed and acceleration corresponding to the reading magnification, and an A / D conversion circuit that converts analog signals from the CCD sensor 28 into digital signals. 43, correction of the output signal due to variations in the CCD sensor 44, the CCD driver 44 that drives the CCD sensor 28, the motor driver 45 that controls the rotation of the drive motor 30 that moves the first and second carriages 18 and 20, and the CCD sensor 28. The image correction unit 46 includes a shading correction circuit to be performed. The CPU 40 is connected to an operation panel 50 having a selection key for selecting an adjustment mode for adjusting the moving speed of the carriages 18 and 20, an instruction key for instructing the start of scanning, and the like.
[0035]
Next, vibration generated in the carriages 18 and 20 will be described.
[0036]
As shown in FIG. 3, the vibrations generated in the carriages 18 and 20 include vibrations generated at startup and vibrations generated from deviation of resonance points when changing from acceleration to constant speed. The greater the difference, the more likely it is. As shown in FIG. 3, when such vibrations of the carriages 18 and 20 enter the area (image area) where the original is actually read, the read image is shaken.
[0037]
Further, the moving speed of the carriage 18 at a constant speed (when reading a document) and the acceleration at the time of acceleration differ depending on the reading magnification. For this reason, there are cases where the resonance point of the carriage 18 can be avoided and an acceleration that can be covered for all magnifications cannot be set.
[0038]
Therefore, several types of acceleration of the carriage 18 are provided, and these accelerations are properly used depending on the magnification. In other words, in order to avoid different resonance points for each acceleration, several types of acceleration are provided, and an acceleration that does not generate a resonance point is selected and set for each magnification.
[0039]
For example, as shown in FIG. 4, accelerations corresponding to a plurality of magnification ranges are set. An appropriate acceleration is selected within the set acceleration region and used under the condition that the acceleration vibration is suppressed as much as possible.
[0040]
Furthermore, since there are structural variations among image bodies of the image reading apparatus, vibration may increase at the acceleration set as described above. For this reason, the acceleration for each magnification is adjusted.
[0041]
For example, in a scanner used in a 65-sheet / minute (CPM) digital copying machine, the acceleration that can be used can be changed within the following range from the preconditions of the machine.
[0042]
The minimum acceleration obtained from the total movement distance of the carriage 18: 8500 mm / S ²
-Maximum acceleration limited from the torque margin of the drive motor 30: 19500 mm / S ²
FIG. 5 and FIG. 6 show examples of acceleration vibrations (velocity fluctuation amounts) at various magnifications when acceleration is set every about 2000 mm / S ² in this acceleration range. However, only the magnification of 60 to 90% is shown. FIG. 5 and FIG. 6 show the maximum amplitude in the image area by measuring the acceleration vibration at each acceleration for each magnification. As shown in FIG. 5 and FIG. 6, the peak of vibration of the carriage 18 is different because the resonance point at each acceleration is different.
[0043]
Example (range of 60% to 90%) shown in FIG. 6, the acceleration is able to cover shaking at each magnification if you have four (acceleration 13200mm / ^{S 2} required).
[0044]
Similarly, for other magnifications, this condition can be easily set if the level of fluctuation with respect to the speed fluctuation amount in the image area is examined in advance.
[0045]
Therefore, depending on the conditions, there should be an increase or decrease in acceleration. In addition, since the load applied to the drive system is more advantageous when the acceleration is slower, the priorities at the time of selection are selected sequentially from the slower.
[0046]
In such a case, if the speed fluctuation amount at which the signal from the carriage 18 does not appear on the image as a shake is 50 mm / s or less, the acceleration 19500 mm / S ² is effective in a narrow range of about 71% to 79%. . Further, as described above, since variations occur in each aircraft, several types of accelerations must be set in order to suppress vibrations in the vicinity of 71% and 79%.
[0047]
Therefore, as shown in FIG. 7, a dedicated chart (reference document) C provided with a straight line (reference line) C1 in the sub-scanning direction (carriage moving direction) is read, and the read image of this dedicated chart C is read. A dedicated adjustment mode having a function of automatically determining an amount of deviation with respect to the reference line C1 and automatically selecting an acceleration with little vibration is provided.
[0048]
That is, the fluctuation of the read pixel with respect to the reference line (vertical line) C1 of the chart C appears as a pixel shift in the read image as shown in FIG. For this reason, the shift amount in the read image is detected as the number of pixels. When a deviation exceeding a predetermined allowable range is confirmed based on the detected deviation amount, the image reading apparatus determines a change in acceleration, and reads again after changing the acceleration. These operations are repeated, and the acceleration is determined when the detected deviation amount is within the allowable range. By performing the above operation for each magnification, the acceleration suitable for the aircraft is selected.
[0049]
Thereby, the acceleration of the carriage in which the deviation amount is within the allowable range can be automatically determined, and the labor for adjusting the control of the carriage can be simplified.
[0050]
For example, the description will be made on the assumption that the shift of the speed fluctuation amount 50 mm / s as shown in FIGS. 5 and 6 corresponds to the shift of 4 pixels with respect to the reference line C1. That is, a case will be described in which the allowable range of the shift amount with respect to the reference line C1 is 4 pixels in the read image of the chart C and the shift amount is adjusted to be within 4 pixels.
[0051]
9A to 9D are diagrams illustrating examples of read images of the reference line C1 of the chart C. FIG.
[0052]
FIG. 9A shows an example of a read image with no deviation. In this case, the read pixels with respect to the reference line C1 of the chart C are arranged on a straight line, and there is no deviation in the read image.
[0053]
FIG. 9B shows an example of a read image having a displacement amount of 2 pixels. In this case, the read pixel with respect to the reference line C1 of the chart C is shifted by one pixel to the left and right with respect to the virtual reference line C1 in the read image of the chart C, and is read with a total shift of two pixels. When the allowable range of the shift amount is 4 pixels, the shift amount of 2 pixels shown in FIG. 9B is determined to be within the allowable range.
[0054]
FIG. 9C shows an example of a read image having a shift amount of 4 pixels. In this case, the read pixels with respect to the reference line C1 of the chart C are shifted by two pixels to the left and right with respect to the virtual reference line C1 in the read image of the chart C, and are read with a total shift of four pixels. When the allowable range of the shift amount is 4 pixels, the shift amount of 4 pixels shown in FIG. 9C is determined to be within the allowable range.
[0055]
FIG. 9D shows an example of a read image having a deviation amount of 8 pixels. In this case, the read pixels with respect to the reference line C1 of the chart C are shifted by 4 pixels to the left and right with respect to the virtual reference line C1 in the read image of the chart C, and read by a total of 8 pixels. When the allowable range of the shift amount is 4 pixels, the shift amount of 8 pixels shown in FIG. 9D is determined to be greater than the allowable range.
[0056]
For example, when the reference line C1 of the chart C is read at a magnification of 50% in order to adjust the reduction side of the reading magnification, the acceleration is set to 8500 mm / S ² as the carriage moving speed, and the chart C is read. A pixel shift amount with respect to the reference line C1 is detected from the read result. When the detected deviation amount is 4 pixels or less as a reference as an allowable range, the moving speed with respect to the magnification is set by the acceleration, and the adjustment to the next magnification is started.
[0057]
When the detected deviation amount is 4 pixels or more, the acceleration is set to 11500 mm / S ² and the adjustment operation similar to the above is performed. The above operation is repeated, and the acceleration is reset until a shift amount of 4 pixels or less is obtained.
[0058]
Further, it is advantageous that the acceleration of the carriage 18 in the image reading apparatus as described above is set as wide as possible as long as it is within a range that satisfies the specifications of the machine body as the image reading apparatus.
[0059]
Further, the vibration of the carriage 18 accompanying acceleration appears on the entire carriage 18. For this reason, the reference line C1 provided in the chart C can be adjusted with at least one line. However, in order to increase the reliability in detecting the shift amount, a plurality of the reference lines C1 are arranged on the chart C as shown in FIG. Reference lines C1,... May be provided.
[0060]
Next, adjustment of the moving speed of the carriage 18 will be described with reference to the flowchart shown in FIG. Here, a case where there are five settable accelerations will be described as an example.
[0061]
First, the operator who performs the adjustment process places the chart C provided with the reference line C1 on the document placement table 12, selects the adjustment mode from the operation panel 50, and instructs the start of the adjustment.
[0062]
Then, the CPU 40 first selects adjustment of the moving speed of the carriage 18 at the minimum magnification n (min) as an adjustment target (step 1). The CPU 40 selects the acceleration 1 as an initial value for the minimum magnification (step 2). The CPU 40 accelerates the carriage 18 at an acceleration of 1 and executes the reading operation of the chart C on the document table 12 (step 3).
[0063]
The CPU 40 obtains pixel data of the read image corresponding to the reference line C1 on the chart C as shown in FIG. 7 based on the read image data. The CPU 40 takes the difference between the maximum value and the minimum value in the main scanning direction of the read pixel corresponding to the reference line C1, and detects the shift amount in the read image. The CPU 40 determines whether or not the shake of the read image is within the allowable range by determining whether or not the detected deviation amount is within a predetermined number of pixels as the allowable range (step 4).
[0064]
If it is determined by this determination that the amount of deviation is within a predetermined number of pixels, that is, if it is determined that the shake of the read image is within the allowable range, the CPU 40 sets the acceleration 1 to the reading magnification n set in step 1 above. Is determined as the acceleration corresponding to.
[0065]
Thus, when the acceleration with respect to the reading magnification n is determined, the CPU 40 determines whether or not the adjusted reading magnification n is the minimum magnification n (min). If the reading magnification n is the minimum magnification n (min) based on this determination, the CPU 40 sets the reading magnification to n + 1 in order to adjust the magnification (n + 1) that is 1% larger than the minimum magnification n (min). (Step 6), the process returns to Step 2.
[0066]
On the other hand, if it is not the minimum magnification n (min), the CPU 40 determines whether or not it is the maximum magnification n (max). If the reading magnification n is not the maximum magnification n (max) based on this determination (step 7), the CPU 40 sets the reading magnification to n + 1 (step 8) and returns to step 2 above. If the reading magnification is the maximum magnification n (max) (step 7), the adjustment processing for all magnifications is terminated.
[0067]
If it is determined in step 4 that the detected deviation amount is not within the predetermined number of pixels as the allowable range, that is, the fluctuation of the read image is not within the allowable range, the CPU 40 determines which amount is within the allowable range. Change the detected acceleration. For example, if the selected acceleration is acceleration 1 (step 9), acceleration 2 is selected as the acceleration (step 10), the process returns to step 3 and the processing from the reading operation of chart C is executed again.
[0068]
If the selected acceleration is acceleration 2 (step 11), the CPU 40 selects acceleration 3 as the acceleration (step 12), returns to step 3 and repeats the processing from the reading operation of chart C again. Execute.
[0069]
If the selected acceleration is acceleration 3 (step 13), the CPU 40 selects acceleration 4 as the acceleration (step 14), returns to step 3 and repeats the processing from the reading operation of chart C again. Execute.
[0070]
If the selected acceleration is acceleration 4 (step 15), the CPU 40 selects acceleration 5 as the acceleration (step 16), returns to step 3 above, and repeats the processing from the reading operation of chart C again. Execute.
[0071]
If the selected acceleration is not acceleration 4 (step 15), that is, if the selected acceleration is acceleration 5, the CPU 40 determines that there is no acceleration to be selected and that adjustment is impossible. An error is reported to the operator through a display unit (not shown) and the process is stopped.
[0072]
The above adjustment is preferably performed for each magnification (in 1% increments), but the vibration corresponding to each magnification of the carriage tends to be as shown in FIGS. For example, adjustment may be performed by thinning out every 10%.
[0073]
As described above, a plurality of carriage accelerations are set, a chart provided with a reference line is read to determine the shaking of the tip, and an appropriate acceleration is automatically selected from the amount of the shaking.
[0074]
As a result, an image without shaking can be obtained at any magnification, and the structure can be simplified and the cost can be reduced without relying on visual adjustment or a special vibration-proof structure.
[0075]
【The invention's effect】
As described above in detail, according to the present invention, an image reading apparatus and an image reading apparatus that prevent vibration of the carriage during image reading, suppress an increase in apparatus and cost, and do not require time and effort for adjusting the carriage. it is possible to provide a method of adjusting.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an image reading apparatus as an embodiment of the present invention.
FIG. 2 is a block diagram for explaining a configuration of a control system of the image reading apparatus.
FIG. 3 is a diagram for explaining a vibration state when the carriage moves.
FIG. 4 is a diagram illustrating an example of setting a carriage acceleration corresponding to a reading magnification.
FIG. 5 is a diagram illustrating a carriage speed fluctuation amount (vibration) corresponding to various reading magnifications.
FIG. 6 is a diagram illustrating a carriage speed fluctuation amount (vibration) corresponding to various reading magnifications.
FIG. 7 is a diagram illustrating a reference line with respect to a chart and a reading direction of a document.
FIG. 8 is a diagram illustrating an example of a read pixel of a reference line in a read image of a chart.
FIG. 9 is a diagram illustrating an example of read pixels on a reference line in a read image of a chart.
FIG. 10 is a diagram showing an example of a chart provided with a plurality of reference lines.
FIG. 11 is a flowchart for explaining a carriage moving speed adjustment process;
[Explanation of symbols]
12 ... Document placing table 18 ... First carriage 20 ... Second carriage 28 ... CCD sensor 30 ... Drive motor 40 ... CPU
41 ... RAM
42 ... ROM
44 ... CCD sensor driver 45 ... Motor driver 50 ... Operation panel

Claims (6)

Scanning means provided below a document placement table on which a document is placed, and reading and scanning one line of a plurality of pixels in the main scanning direction with respect to the document on the document placement table;
The scanning unit is accelerated in the sub-scanning direction of the document on the document table from any one of a plurality of types of acceleration from outside the document reading area, and a constant moving speed corresponding to the reading magnification in the document reading area. Moving means to move with,
A reading unit that moves the scanning unit in the sub-scanning direction by the moving unit and reads a reference document provided with at least one reference line placed on the document table;
Determining means for determining whether or not a deviation amount of the read pixel with respect to a reference line on the reference document read by the reading means is within a predetermined allowable range;
A magnification setting means for setting a reading magnification to be adjusted for adjusting an acceleration when the scanning means is accelerated by the moving means;
As an acceleration for accelerating the scanning unit at the scanning magnification set by the magnification setting unit, an acceleration at which the shift amount of the read pixel is determined to be within an allowable range by the determination unit is selected from the plurality of types of accelerations. Acceleration setting means for setting;
Control means for sequentially changing the reading magnification set by the magnification setting means and repeatedly executing the processing by the acceleration setting means;
An image reading apparatus comprising: The acceleration setting means sequentially changes the acceleration of the moving means at each reading magnification, determines whether the deviation amount of the read pixel is within an allowable range by the determination means, and the deviation amount is within the allowable range by the determination means. The acceleration when it is determined to be associated with the reading magnification,
The image reading apparatus according to claim 1, wherein: In the plurality of types of acceleration, when there is no acceleration for which the amount of deviation of the read pixel is determined to be within an allowable range by the determination unit, a notification unit that notifies that adjustment is impossible is provided.
The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. A scanning unit that is provided below the document placing table on which the document is placed and reads and scans one line of a plurality of pixels in the main scanning direction with respect to the document on the document placing table, and the scanning unit is used as the document. Moving means for accelerating at any one of a plurality of types of acceleration from outside the document reading area in the sub-scanning direction of the document on the mounting table and moving at a constant moving speed corresponding to the reading magnification in the document reading area; An adjustment method used for an image reading apparatus having
Set the reading magnification of the adjustment object to adjust the acceleration when accelerating the scanning means by the moving means,
As the acceleration when accelerating the scanning means at the set reading magnification, select one of the accelerations of the plurality of types,
Using the selected acceleration, the scanning means is moved in the sub-scanning direction by the moving means to read a reference document provided with at least one reference line placed on the document placement table,
A determination is made as to whether or not the amount of deviation of the read pixel relative to the reference line on the read reference document is within a predetermined allowable range;
Based on this determination, the acceleration determined that the deviation amount is within the allowable range is set in association with the reading magnification,
The setting of the reading magnification is sequentially changed, and the selection, reading, determination, and setting processes are repeatedly executed at each reading magnification.
A method for adjusting an image reading apparatus. In the reading, the reference document is read by sequentially changing the acceleration of the moving means at each reading magnification ,
The determination determines whether or not the amount of deviation of the read pixel when the reference document is read at each acceleration is within an allowable range,
In the setting, the acceleration when the deviation amount is determined to be within the allowable range by the determination is set in association with the reading magnification.
The method of adjusting an image reading apparatus according to claim 4, wherein: In the above-mentioned plurality of types of acceleration, if there is no acceleration at which the shift amount of the read pixel is determined to be within an allowable range based on the above determination, a notification is made that adjustment is impossible.
6. The method for adjusting an image reading apparatus according to claim 4, wherein the adjustment method is the same as the above.

Images