JPH11136454A - Image reading device - Google Patents

Abstract

(57) [PROBLEMS] To provide an image reading apparatus which improves the efficiency of repetitive copy processing, and is capable of adjusting the writing position on a photosensitive member when reading the same original repeatedly in reading a color original. To provide. SOLUTION: In a series of image reading operations, reading scanning means (1) for scanning an original to read an image, and a first position at the time of the first reading of the series of image reading operations of the reading scanning means (1). Start reading from 2
In the subsequent reading, reading control is started from a second position closer to the document position than the first position, and the reading control means returns the reading scanning means (1) to the first position after a series of image reading operations is completed. (2) An image reading apparatus comprising:

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus used in a scanner, a black-and-white electrophotographic copying machine, a color electrophotographic copying machine, a laser printer, a facsimile, and the like. The present invention relates to an image reading apparatus having the function of performing

[0002]

2. Description of the Related Art Many conventional image reading apparatuses change a reading density by moving a moving body constituting a reading optical system at a speed different from that at the same magnification in order to perform magnification processing. The method has been adopted. FIG. 6 is a diagram showing, for each target speed, the approach distance required for the traveling body to reach the target speed until the traveling body reaches the leading end of the document, and the movement start position of the traveling body is indicated by a home position (denoted by HP in the figure). age,
Assuming that the acceleration at the time of rising is constant, the running body needs the approach distance 1, the approach distance 2, and the approach distance 3 to reach the target speed 1, the target speed 2, and the target speed 3, respectively. Here, the time required for the traveling body to reach the leading end of the document decreases in the order of target speed 1, target speed 2, and target speed 3. On the other hand, in the case of repeatedly reading the same original stopped on the contact gas, such as when reading a color original, the traveling body must be read each time one reading is completed in order to match the writing position on the rotating photoreceptor surface. Is always returned to the home position, and the approaching is started from that position, the alignment with the writing position on the photosensitive member cannot be made in time. If the approach distance is the approach distance 1 equal to the distance between the home position and the leading edge of the document (in the case of the target speed 1), the speed of the traveling body is changed to the target speed 2 or the target speed from the relationship with the magnification. If it should be set to 3, it is not necessary to start the run from the home position because the run distance is short, but in the past, the run was started uniformly from the home position regardless of the target speed. . Despite the low target speed,
To always start the run after returning to the home position is wasting wasted time, and the efficiency of repeated copy processing is reduced. Therefore, as shown in FIG. 7, conventionally, according to the difference in the target speed of the traveling body, a home position (indicated by HP1 to HP3 in the figure) is set within a range in which a necessary approach distance can be obtained according to each. Have been done. Here, HP1 is the highest target speed 1 of the traveling body.
Is the movement start position of the traveling body at the time of obtaining, and indicates the home position HP in FIG. For example, Japanese Patent Application Laid-Open
According to Japanese Patent No. 1409, the home position at the start of reading of a copying machine is changed according to a set magnification to realize the highest efficiency CPM at the time of copying a plurality of sheets.

[0003]

As described above, the method of changing the home position at the start of reading according to the set magnification to shorten the approach distance to the leading edge of the original as the target speed becomes lower is repeated. This improves copy processing efficiency and facilitates time adjustment for writing position adjustment on the photoconductor when reading the same original repeatedly in reading a color original.However, depending on the reading start position, This position is closer to the leading end of the document than the reference white plate, and as a result, the reference white plate cannot be read from the reading start position to the leading end of the document. In order to deal with such a problem, in the above-described conventional example, when performing shading correction, the scanning body is once returned to a position on the reference white plate or a position beyond the reference white plate on the side opposite to the leading end of the document, and thereafter the document is moved to the document side. The shading correction is performed by reading the reference white plate at the time of scanning, so that the shading correction takes time and the control of the movement of the traveling body in the front-rear direction is complicated. The present invention has been made in view of the above, and the first reading start position of a series of image reading operations is a home position set at a position far from the leading edge of the document beyond the reference white plate, and the reference is set at the time of the first reading scan. Read the white plate and perform shading correction.
In the second and subsequent readings, the set position at which the required target speed of the traveling body is obtained is set as a reading start position (for example, a position between the leading edge of the document and the reference white plate). Control to return to the original position, shortening the time required for shading correction, simplifying the movement control of the running body in the front-rear direction, improving the efficiency of repeated copy processing, and reading the same original when reading color originals It is an object of the present invention to provide an image reading apparatus that facilitates time adjustment of writing position alignment on a photoreceptor when reading is repeated.

[0004]

In order to achieve the above object,
According to a first aspect of the present invention, in an image reading apparatus that scans a document by scanning a traveling body, a reading scanning unit that scans a document to read an image during a series of image reading operations, and a series of image reading of the reading scanning unit. At the first reading of the operation, reading is started from the first position. At the second and subsequent readings, reading is started from the second position closer to the leading end position of the document than the first position, and a series of image reading operations is completed. A reading control unit for returning the reading scanning unit to the first position later. According to a second aspect of the present invention, in the image reading apparatus according to the first aspect, a reference white plate provided between the first position and the second position, and data of the reference white plate read by the reading scanning unit. And a shading correction unit that performs shading correction based on the reference white board by the reading scanning unit during the first reading of a series of image reading operations, and then reads the reference white board. It is characterized in that the shading correction unit performs shading correction based on the data. Claim 3
According to the invention, in the image reading apparatus according to claim 2, when a series of image reading operations is performed by reading a single document a plurality of times, the second position is set to the reference white plate and the document leading edge position. It is characterized in that it is set between. According to a fourth aspect of the present invention, in the image reading apparatus according to the second aspect, the image reading apparatus further includes a designated number generating unit that issues an instruction to return the reading scanning unit to the first position every designated number of times, wherein the reading control unit includes: When receiving an instruction generated by the designated number generating unit without waiting for a series of image reading operations, the reading scanning unit is returned to the first position. The invention of claim 5 is
5. The image reading apparatus according to claim 4, wherein the second position is set between the reference white plate and a document leading edge position. According to a sixth aspect of the present invention, in the image reading apparatus according to the second aspect, the second position is provided between the reference white plate and the leading end position of the document, and during the first reading scan of a series of image reading operations, A document determination unit for determining whether to read an image document or a monochrome image document; and a designated number generation unit for issuing an instruction to return the reading scanning unit to the first position every designated number of times. When the document determining unit determines that the document is a color image document, the control unit causes the shading correction to be performed only at the first reading in a series of scanning scans on one document, and controls the entire document for the one document. After the reading operation is completed, the reading scanning unit is returned to the first position, and if the document determining unit determines that the monochrome document is to be read, the reading scanning unit performs the specified number of reading scans based on the instruction generated by the specified number generating unit. When the is performed, it is characterized by returning the read scanning section in the first position.

[0005]

According to the first aspect of the present invention, the reading control section starts reading the reading scanning section from the first position at the first reading of a series of image reading operations, and the first reading is performed at the second and subsequent reading. Since reading is started from a second position closer to the leading end position of the document than the position and is returned to the first position after a series of image reading operations is completed, the second position of the second or subsequent reading start is set. By setting the shortest approach distance at which the required target speed of the traveling body can be obtained, the reading start time for the second and subsequent reading can be reduced. Claim 2
According to the invention, in addition to the invention of the image reading device configured as in claim 1, a reference white plate is provided between a first position and a second position, and the reference reading plate read by the reading scanning unit. The reading control unit includes a shading correction unit that performs shading correction based on the data of the white plate, so that the reading control unit reads the reference white plate at the first reading of a series of image reading operations of the reading scanning unit, and performs the shading. Since the shading correction can be performed by the correction unit, it is not necessary to return the scanning body to a position on the reference white plate or a position farther from the document side than the reference white plate to perform the shading correction. According to a third aspect of the present invention, in addition to the image reading apparatus of the second aspect, when a series of image reading operations is performed by reading a single document a plurality of times, the second image reading operation is performed. Is located between the reference white plate and the leading edge of the document, so that the shading correction data is collected only at the first reading for one document reading, and is collected at the first time for the subsequent reading of the same document. Since the shading correction using the correction data is performed, the number of times of reading can be reduced. According to a fourth aspect of the present invention, in addition to the image reading apparatus of the second aspect, an instruction to return the reading scanning unit to the first position is generated every number of times specified by the specified number generating unit. When the instruction to generate the designated number of times is received without waiting for a series of image reading operations, the reading control unit returns the reading scanning unit to the first position, so that there is a problem at the time of shading correction. By setting the set number of occurrences that does not occur in the specified number generation section, it is possible to perform stable and efficient shading correction with stable reading. According to a fifth aspect of the present invention, in addition to the image reading apparatus of the fourth aspect, since the second position is between the reference white plate and the document leading edge position, a series of image reading operations is completed. Until then, shading correction can be performed once every set number of times set in the designated number generation unit. The invention of claim 6 is the invention of claim 2
In addition to the invention of the image reading apparatus configured as described above, when the document determination unit determines that the reading of a color image is to be performed, the reading control unit performs shading only for the first reading of each document. After performing the correction, the reading scanning unit is returned to the first position after the reading operation of the document for each sheet is completed, and when it is determined that the reading of the document is a monochrome image,
Regardless of whether a series of image reading operations is completed or not, since the read scanning unit is operated to return to the first position when the specified number of reading scans is completed according to an instruction from the specified number generating unit, In the reading of a color image, the shading correction can be performed only for the first reading of a single document, and the specified number of times is set in the designated number generating unit so that no shading problem occurs in the reading of a black and white image. This makes it possible to perform efficient shading correction with stable reading.

[0006]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a longitudinal sectional view of a main part of an image reading apparatus (reading optical system) used in a color copying machine. Since the configuration and operation functions of the color copying machine are already known, only the outline necessary for the present invention will be described. In FIG. 1, light emitted from a light source 11 irradiates a document surface (not shown) pressed against a pressure plate 22 on a contact glass 21. The light reflected from the document surface is reflected by the first mirror 12, the second mirror 13, and the third mirror 14, passes through the lens 15, and forms an image on the CCD 16. C
The CD 16 receives a light amount corresponding to the document image, converts the light amount into an electric signal, and outputs the electric signal. The electric signal output from the CD 16 is guided to an image processing circuit on a circuit board (not shown) and subjected to various image processing. Also, the reading scanning unit 1
First scanning unit 1 including light source 11 and first mirror 12
7, a second scanning unit 18 including a second mirror 13 and a third mirror 14, a lens 15, a CCD 16, and the like. Here, the first scanning unit 17 and the second scanning unit 18, which are the traveling bodies of the reading scanning unit 1, read the document image by moving in parallel from right to left in the figure below the document surface. Further, prior to the start of reading the document image, the reading scanning unit 1 reads the reference white plate 3 placed on the right end of the contact glass 21. The reference white plate 3 is arranged to be elongated corresponding to the reading width in the main scanning direction, and the read data is stored in the line memory 7 (see FIG. 2). The shading correction unit 4 performs shading correction using the shading data stored in the line memory 7. Further, at the start of the first scanning of the scanning unit 1, the first scanning unit 17 and the second scanning unit 18 perform scanning from a predetermined position. Therefore, the stop detecting element 1 is configured to stop the first scanning unit 17 and the second scanning unit 18 at a home position (designated as HP in the figure) as a designated position.
9 is set. In the present example, a detection signal is output from the stop detection element 19 when a predetermined portion of the first scanning unit 17 reaches a position immediately below the stop detection element 19.

FIG. 2 is a block diagram of a main part around the reading control unit 2. The operation of the present invention will be described with reference to FIGS. 1 and 2. First, when a read instruction is transmitted to a read control unit 2 from a main control unit or the like (not shown) by operating an operation unit (not shown), An operation command signal is output from the CPU in each section to each section. During a series of image reading operations, the reading control unit 2 scans a document to read an image, and reads the first scanning unit 17 and the second scanning unit 18 of the reading scanning unit 1.
A movement instruction is issued to the traveling body drive unit 8 that drives the vehicle. First scanning unit 17 and second scanning unit 1 stopped at the home position
Reference numeral 8 receives a movement instruction from the traveling body drive unit 8 and moves toward the leading end of the document (document edge closest to the reference white plate 3) which is stationary on the contact glass 21. that time,
Each scanning unit passes through a position immediately below the reference white plate 3 set between the home position and the leading end of the document, so that the reference thin plate is read. The reflected light from the reference white plate 3 is guided to the CCD 16 and subjected to photoelectric conversion, and is output for each of R, G, and B of color. The output of the CCD 16 is amplified by the analog processing unit 23, gain-adjusted, input to the A / D conversion unit 24, and converted into an 8-bit digital signal for each color. A /
The data of the reference white board 3 processed by the D conversion unit 24 is stored in the line memory 7 that stores data (3 × 5K × 8 bits) for one line of each color.

Next, when the first scanning unit 17 and the second scanning unit 18 of the reading scanning unit 1 move on the original, the original image data is read. The document image data that has passed through the CCD 16 is output for each of the R, G, and B colors, amplified by the analog treatment section 23, and subjected to gain adjustment. Then, A /
The signals are input to the D conversion unit 24 and are converted into 8-bit digital signals for each color. Further, this data is input to the shading correction unit 4 and subjected to shading correction. At the time of shading correction, shading correction is performed using the read data of the reference white plate 3 stored in the line memory 7. If one same color original,
When reading is performed a plurality of times, the reading control unit 2 issues an instruction to the traveling unit driving unit 8 to move the first scanning unit 17 and the second scanning unit 18 at the first position to the home position, which is the first position. After the start of the movement, the reference scanning whiteboard 3 is read by the reading and scanning unit 1 in the course of the movement (outbound path) and stored in the line memory 7. Next, when the first scanning unit 17 and the second scanning unit 18 move below the original and take in the original image data, the shading correction unit 4 performs shading correction using the stored data of the reference white plate 3. Further, the reading control unit 2 determines the minimum approach distance required to obtain the target speed of the second and subsequent scanning units until both scanning units reach the rear end of the original (the original edge farthest from the reference white plate). The second and subsequent reading start positions are calculated to determine the return distance. Thereafter, when the rear end of the document is read, the return operation is started, and the first scanning unit 17 and the second scanning unit 18 are returned to the new reading start position calculated above.

Next, in the second reading, scanning is started from the above-mentioned return location, that is, a second position between the home position and the leading end of the document. If the second position is closer to the leading end side of the document than the reference white plate 3, the reference white plate 3 is not included in the movement path of the scanning unit in the second and subsequent readings, so that the reference white plate is not read and only the original image data is read. Will be taken. Therefore, the shading correction for the second and subsequent read images is performed using the data of the reference white plate 3 read at the time of the first read. Further, when the reading of the first color document is completed, the reading control unit 2 instructs the traveling unit driving unit 8 to return the first scanning unit 17 and the second scanning unit 18 to the home position. Therefore, the traveling body drive unit 8 receiving the instruction from the reading control unit 2 performs the first scanning unit 17 and the second scanning unit 18
To the home position, and the reading control unit 2
Receives the signal emitted from the stop detection element 19 and stops at a place advanced a certain distance. It goes without saying that the position corresponds to the actual home position. When reading the second and subsequent color originals, scanning starts from the home position as in the case of the first sheet, and follows the same reading process as described above.

The designated number generating unit 5 in FIG.
The number of scans can be arbitrarily specified by an operation from an operation unit (not shown). In other words, the designated number generating unit 5 is a unit that generates an instruction to return the reading scanning unit to the first position every specified number of times. Further, the number of times of reading by the reading scanning unit 1 can be taken in from the traveling body driving unit 8 or the like. As a result of comparing the two times, a signal is generated to notify the reading control unit 2 when they match with each other. I have. Therefore, when the reading control unit 2 receives the generation signal from the specified number of generation units 5 before a series of image reading operations, the reading control unit 2 performs the first scanning unit 17 after the last scanning after the specified number of scans has been performed. Then, an instruction is issued to the traveling body drive unit 8 to return the second scanning unit 18 to the home position. Therefore,
As long as the reading control unit 2 does not end the series of image reading operations, the reading control unit 2 causes each of the scanning units 17 and 18 to return to the second position for each number of times set in the designated number generating unit 5,
At the end of the last scan, the first scanning unit 17 and the second scanning unit 18
To return to the home position. Although not shown, a document determination unit 6 is set in the reading control unit 2 of FIG. The document determination unit 6 can determine whether a color document is read or a black-and-white document is read during the first reading scan of a series of image reading operations. Therefore, when it is determined by the document determination section 6 that a color document is to be read, the information is transmitted to the reading control section 2 and is necessary for performing the above-described reading of the same color document a plurality of times. Operation can be instructed.

When it is determined by the document determining section 6 that a monochrome document is to be read, the information is transmitted to the reading control section 2 and the designated number of generations section 5 is performed before a series of image reading operations.
When the generated signal is received, the operation for instructing the traveling body drive unit 8 to return the first scanning unit 17 and the second scanning unit 18 to the home position is performed. That is, in the case of a black-and-white image, regardless of how many times a single original is read or how many originals are read, the time to return to the home position (first position) is as follows. Specified count generator 5
(Usually, the number of readings is larger than the number of readings for one color document). This is because, in the case of a monochrome image, even with such a shading correction frequency, there is no significant effect on the image quality. As a result, when reading a black-and-white image, the scanning unit moves from the home position toward the document during the first reading operation to collect shading correction data, and the second and subsequent reading operations up to the specified number of times perform the second reading operation. It is performed from the position. The next collection of shading correction data is performed after the reading of the designated number of times.

FIG. 3 is a diagram showing an operation pattern when the first scanning section 17 and the second scanning section 18 constituting the reading scanning section 1 always start traveling from the home position and read an original image. That is, during the first reading operation, the reference white plate 3 located between the home position and the leading end position of the document is read, and shading correction is performed on the document image data. When the scanning section reaches the trailing end of the document, the first return period starts, and the scanning section returns to the home position again. Then 2
The second reading starts from the home position again, reads the reference white board 3, performs shading correction on the document image data, and thereafter repeats the same process. Therefore,
In this case, the first reading distance, the first return distance, and the second reading distance are all equal.

FIG. 4 shows that at the time of the first reading of a series of image reading operations, the original image data is read while traveling from the home position, and the second and subsequent reading start positions are required to obtain the target speed of the running body. The state in which the reading is performed so as to be the minimum approach distance is shown. That is, during the first reading, the reference white plate 3 located between the home position and the leading end position of the document is read, and shading correction is performed on the document image data. While arriving at the rear end of the document, the reading control unit 2 calculates the minimum approach distance required to obtain the target speed of the traveling body for the second and subsequent times, and obtains the return distance. When the document reaches the trailing end, the first return period is reached, and the document returns by the return distance determined above. Therefore,
As shown in the figure, if the second reading start position (second position) is closer to the leading end position of the document than the reference white plate 3 by returning by the first return distance, the reference white plate 3 starts from the second reading. , And only the original image data is read. For the second and subsequent original image data, shading correction is performed using the data of the reference white plate 3 read at the first reading. In this case, the first return distance is equal to the second read distance.

FIG. 5 is a flowchart showing a main operation of the present invention in a series of image reading operations. The operation will be described with reference to FIGS. When the reading control unit 2 receives a reading operation command, first, the light source 1 of the reading scanning unit 1 is read.
1 is turned on (step S1). Next, the reading control unit 2
Receiving the instruction, the traveling body drive unit 8 moves the traveling body (carriage) of the first scanning unit 17 and the second scanning unit 18 stopped at the home position in the document direction (S2). Thereafter, it is asked whether or not the traveling body has reached the reading position of the reference white plate 3 (S3). If the reading position of the reference white plate 3 has not been reached (S3 No), the process waits until the reading position is reached. When the traveling body reaches the reading position of the reference white board 3 (S3 Yes), the reading scanning unit 1 reads the reference white board 3 (S4) and stores it in the line memory 7 (S4).
5). Next, the traveling body moves further in the document direction and reads document image data (S6). Shading correction unit 4
Performs shading correction using the stored data of the reference whiteboard 3 (S7). Next, the reading control unit 2 calculates the reading start position from the minimum approach distance required to obtain the target speed of the traveling body for the second and subsequent times (S8). Furthermore, it is asked whether or not the traveling body has reached the reversing position (S9). If the traveling body has not reached the reversing position (S9 No), the process waits until it reaches the reversing position. Thereafter, when the traveling body reaches the reverse position (S9Y
es) It is asked whether a series of image reading operations has been completed (S10). If a series of image reading operations has not been completed (No in S10), a return operation is performed so that the return distance has already been calculated (S13), and the traveling body is caused to travel for the second and subsequent readings (S14). It is determined whether the reference white board 3 can be read based on the determination of the second or later reading start position (S15). If the reference white board 3
If it is possible to read (S15 Yes), step S15
3, the reference white plate 3 is read (S3 Yes, S4) after waiting until the reading position of the reference white plate 3 is reached, and steps S3 to S15 are repeated until the reading of step S10 is completed. If the reading of the reference white plate 3 is not possible (No in S15), the process returns to step S6, and only the document image data is read without reading the reference white plate 3 (S6). Repeat until reading is completed. Step S
10, when a series of image reading operations is completed (S10 Yes), the light source 11 of the reading and scanning unit 1 is turned off (S11), and the traveling body is returned to the home position (S1).
2).

[0015]

As described above, according to the first aspect of the present invention,
By setting the second position for starting the second and subsequent readings to be the shortest approach distance for obtaining the required target speed of the traveling body, shortening the reading start time for the second and subsequent readings. As a result, it is possible to improve the efficiency of the repetitive copying process and make it possible to time the writing of the photoreceptor when the same original is repeatedly read in reading the color original. In other words, in the second and subsequent readings, without returning to the home position at a position far from the document, the reading position is returned to the second position, which is closer, and the reading operation is started from that position. Becomes
The timing for writing each piece of image information on the rotating photosensitive member can be easily set. According to the second aspect of the present invention, the first aspect is provided.
In addition to the invention of the image reading device, the reading control section may cause the reference white board to be read at the first reading in a series of image reading operations of the reading scanning section, and perform shading correction by the shading correction section. It is no longer necessary to return the scanning unit to a position on the reference white plate or farther from the document side than the reference white plate in order to perform shading correction. Can be prevented from becoming complicated. According to the invention of claim 3, when a series of image reading operations is performed by reading a single document a plurality of times, the second position is between the reference white plate and the leading edge position of the document. Since the shading correction data is collected only for the first reading of one original reading, and in the subsequent reading of the same original, shading correction using the correction data collected for the first time is performed. The number of times of reading for reading can be reduced. According to the invention of claim 4, in addition to the invention of the image reading device of claim 2, by setting a set number of times in the designated number generating section so as not to cause a problem of shading correction, reading is stable and efficient. Since good shading correction can be performed, it is possible to provide an image reading apparatus with stable reading and high processing efficiency. According to the invention of claim 5, in addition to the invention of the image reading apparatus of claim 4, shading correction is performed once until a series of image reading operations is completed or at every set number set in the designated number generation unit. As a result, it is possible to provide an image reading apparatus with stable reading and high processing efficiency. According to the invention of claim 6, in addition to the invention of the image reading apparatus of claim 2, in reading an original of a color image, shading correction can be performed only for the first reading of one original, and a monochrome image can be read. It is now possible to set the specified number of times in the specified number generating section so that shading problems do not occur when reading an original, so that it is possible to provide an image reading apparatus with stable reading and high processing efficiency. became.

[Brief description of the drawings]

FIG. 1 is a side view of a main part of an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a main part around a reading control unit of the image reading apparatus according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating a state in which a traveling body constantly scans and reads from a first position.

FIG. 4 is an explanatory diagram illustrating a state in which the traveling body is scanned and read from a second position during the second and subsequent readings.

FIG. 5 is a flowchart showing main operations of the image reading apparatus of the present invention.

FIG. 6 is an explanatory diagram illustrating a relationship between a target speed of a traveling body and a running distance.

FIG. 7 is an explanatory diagram illustrating a manner in which the approach distance is changed according to a target speed of the traveling body.

[Explanation of symbols]

1 reading scanning section, 2 reading control section, 3 reference white board, 4
Shading correction unit, 5 designated number generation unit, 6 document judgment unit, 7 line memory, 8 traveling unit drive unit,
11 light source, 17 first scanning unit, 18 second scanning unit, 1
9 Stop detection element

Claims (6)

[Claims] In an image reading apparatus for scanning a traveling body to read an original, in a series of image reading operations, a reading scanning section for scanning an original to read an image, and a series of image reading operations of the reading scanning section. In the first reading, the reading is started from the first position, and in the second and subsequent readings, reading is started from the second position closer to the leading end position of the document than the first position. An image reading device comprising: a reading control unit that returns the reading scanning unit to a first position. 2. The image reading apparatus according to claim 1, wherein
A reference white plate provided between the first position and the second position, and a shading correction unit that performs shading correction based on data of the reference white plate read by the reading scanning unit, wherein the reading control The unit, at the first reading of a series of image reading operation, after reading the reference white board by the reading scanning unit, and causes the shading correction unit to perform shading correction based on the data of the reference white board. Image reading device. 3. The image reading apparatus according to claim 2, wherein
In a case where a series of image reading operations is performed by reading a single document a plurality of times, the second position is set between the reference white plate and the leading edge position of the document. 4. The image reading apparatus according to claim 2, wherein
A designated number generating unit for issuing an instruction to return the reading scanning unit to the first position every designated number of times; the reading control unit generates the designated number of times without waiting for a series of image reading operations; An image reading apparatus, wherein upon receiving an instruction, returns the reading scanning unit to a first position. 5. The image reading device according to claim 4, wherein
The image reading apparatus according to claim 1, wherein the second position is set between the reference white plate and a document leading edge position. 6. The image reading device according to claim 2, wherein
The second position is provided between the reference white plate and the leading edge position of the document, and during the first reading scan of a series of image reading operations,
A document determination unit that determines whether to read a color image document or a monochrome image document, and a designated number generation unit that issues an instruction to return the reading scanning unit to the first position every designated number of times. When the document determination unit determines that a color image is to be read, the reading control unit causes the shading correction to be performed only at the first reading in a series of scanning scans on one document, and performs the shading correction on the one document. After the completion of all reading operations, the reading scanning unit is returned to the first position, and if the document determining unit determines that the reading of a black and white image document is to be performed, the reading scanning of the specified number of times is performed based on an instruction generated by the specified number generating unit. An image reading apparatus that returns the reading and scanning unit to a first position at the time when the image reading is performed.