JP2002010026A - Apparatus and method for reading image and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable maintenance of a productivity in response to an image quality while maintaining an S/N. SOLUTION: In an apparatus for reading an image for generating an image signal by illuminating an original, photodetecting its reflected light and photoelectrically converting the light, an original reading speed V is controlled in response to an original reading resolution D so as to satisfy D*V=N (N: arbitrary constant), wherein D (dpi) is the original reading resolution and V (mm/s) is the original reading speed at that time. Thus, both high image quality reading and high speed reading can be conducted by using the one apparatus for reading the image without enhancing performances photosensitivities of an illumination system, a lens and a CCD.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image reading device,
The present invention relates to an image reading method and a storage medium, and particularly to a technique suitable for improving the productivity of an image reading apparatus.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view for explaining the structure of a main part of an image reading apparatus which is generally widely used. Hereinafter, the configuration of the main part of the image reading apparatus will be described with reference to the accompanying drawings. In FIG. 6, a document 17 placed on a document tray 12 of a document feeder 11 is transported by a paper feed separation unit 13, electrostatically attracted to a document moving belt 14, and transported to a predetermined position on the document table glass 1. Is done.

An original image, which is illuminated by an illumination lamp 3 disposed on a first mirror base 2 serving as a scanning optical unit, and is a reflected light of the illumination lamp 3, is also disposed on a first mirror base 2. Second and third mirror base 5 by mirror 4
Is reflected to Then, the light is reflected by the second mirror 6 and the third mirror 7 and condensed by the lens 8 to form an image on the light receiving surface of the CCD 9 provided as a reading element.

[0004] First mirror stand 2, second and third mirror stand 5
Is supported by a rail (not shown), and the optical motor 1
It can be moved in the direction of the arrow with the rotation of 0. A stepping motor is used as the optical motor 10 and is driven by a current supplied from an optical motor driver board (not shown). When the image reading on the platen glass 1 is completed, the sheet is immediately conveyed to the sheet discharging roller 15 by the document conveying belt and discharged to the document tray by the sheet discharging roller 15.

[0005] As the image reading method, there are used two methods, a scan reading method and a flowing reading method. The scan reading method is configured to read an image by fixing a document on a document glass and moving a scanning optical system. On the other hand, the flow reading system is configured such that the scanning optical system is fixed and an image is read by moving a document with a document moving belt.

Further, in the case of a high-speed image reading device,
The CCD 9 has a resolution of 400 dpi, and the moving speed of the scanning optical system is the readable speed of the CCD 9.
It is configured to be movable at 40 mm / s.

The optical system has a reading speed of 540 mm /
s sufficient S / D at a resolution of 400 dpi of the CCD 9
N is obtained. Further, since the LTR original (sub-scanning size 216 mm) is configured to be able to read an image at an original spacing of 144 mm using a flowing scanning method, the number of originals read per unit time is 540 / (216 + 144) = 1. It is 5 sheets / s, and has an original reading speed of 90 cpm.

On the other hand, in the case of a high-quality image reading device,
The CCD has a resolution of 600 dpi, and the moving speed of the scanning optical system is 360, which is the readable speed of the CCD.
It is configured to be movable at mm / s. The optical system has a reading speed of 360 mm / s and a CCD resolution of 600 mm.
The configuration is such that a sufficient S / N is obtained at dpi.

Further, an LTR original (sub-scan size 216
mm) using the flow reading method, and a document interval of 144 m
m, the number of originals read per unit time is 360 / (216+
144) = 1 sheet / s, and has a document reading speed of 60 cpm.

[0010]

In the above-described image reading apparatus, the high-speed image reading apparatus is 400 dp.
i, and a high-quality image reading device has a resolution of 600 dpi. That is, a high-speed image reading device has a low resolution, while a high-resolution image reading device has a low reading speed.

This is because, by increasing the image reading speed, the amount of light per unit time is reduced, and the S / N ratio is reduced in principle. In addition, the higher the image quality, the smaller the amount of light per unit area, which in principle lowers the S / N ratio.

For this reason, in order to realize a high-speed and high-quality image reading device while maintaining a high S / N, development of brightening the illumination system and the lens and development of increasing the light sensitivity of the CCD 9 are performed. ing.

Technically, it is possible to solve the above-mentioned problems, but problems such as a rise in the temperature of the illumination system and the CCD 9 and an increase in the cost of the illumination system, the lens, and the CCD occur. Therefore, in order to realize a high-speed and high-quality image reading device as a mass-produced product while maintaining a high S / N,
Many further technical challenges remain.

Meanwhile, in a specialty store such as a copy shop, it is necessary to install both a high-speed and low-resolution device and a low-speed and high-resolution device according to a customer's request. However, it is difficult to install the two devices because there is a problem of an installation space and a problem of a large investment amount such as a main body cost. Therefore, an image having both the demand for high productivity and the demand for high image quality is required. There is an increasing demand for commercialization of the reading device.

In most offices and homes, customers purchase high-speed, low-resolution devices or low-speed, high-resolution devices depending on the application. There is a problem that the requirements of the above cannot be satisfied.

Further, when the document feeder is operated at a high speed and the document is conveyed at a high speed, the possibility of the occurrence of a jam increases, thereby causing a problem that the productivity due to the jam decreases.
There was a problem that the lifetime productivity of the image reading device was reduced. SUMMARY OF THE INVENTION In view of the above problems, it is a first object of the present invention to maintain productivity in accordance with image quality while maintaining S / N. It is a second object of the present invention to be able to realize both a request for high-quality image reading and a request for high-speed image reading with one apparatus without significantly increasing the cost. Also, without increasing the document conveying speed, it is possible to improve the moving accuracy of the scanning optical system and stabilize the paper conveying accuracy,
A third object is to suppress an increase in the jam occurrence rate of the document feeder. A fourth object of the present invention is to provide a high-sided productivity and reduce the influence of a jam of the document feeder for a two-sided original.

[0017]

According to the present invention, there is provided an image reading apparatus for illuminating a document, receiving reflected light of the document, and performing photoelectric conversion to generate an image signal. To D (dp
i), and the original reading speed at that time is V (mm / s)
Then, the document reading speed V is controlled according to the document reading resolution D so that D * V = N (N: an arbitrary constant). Another feature of the present invention is that the document reading speed V is a difference (V1-V2) between the sub-scanning speed V1 of the scanning optical system and the document moving speed V2 of the document moving system. Features. Another feature of the present invention is that the scanning movement direction of the scanning optical system is opposite to the document movement direction of the document movement system. Another feature of the present invention is that the reading start position of the document is sequentially moved to the upstream side in the moving direction of the document. Also,
Another feature of the present invention is that, when reading the original, the scanning movement direction of the scanning optical system and the original movement direction of the original movement system are changed when reading the first side of the double-sided original and reading the second side. The feature is that the direction is set to be opposite each time.

The image reading method according to the present invention is directed to an image reading method for illuminating an original, receiving reflected light of the original, and performing photoelectric conversion to generate an image signal.
When the resolution for reading the original is D (dpi) and the original reading speed at that time is V (mm / s),
The document reading speed V is controlled in accordance with the document reading resolution D such that * V = N (N: an arbitrary constant). Another feature of the present invention is that the document reading speed V is a difference (V1-V2) between the sub-scanning speed V1 of the scanning optical system and the document moving speed V2 of the document moving system. Features. Another feature of the present invention is that the scanning movement direction of the scanning optical system is opposite to the document movement direction of the document movement system. Another feature of the present invention is that the reading start position of the document is sequentially moved to the upstream side in the moving direction of the document. Another feature of the present invention is that, when reading the original, the scanning movement direction of the scanning optical system and the original movement direction of the original movement system are different from those at the time of reading the first side of a double-sided original. The reading direction is set to be opposite to the reading direction.

A storage medium according to the present invention is characterized in that a program constituting each means described above is stored so as to be readable from a computer. Another feature of the present invention is that a program for executing the above-described image reading method is stored so as to be readable from a computer.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image reading apparatus, an image reading method and a storage medium according to the present invention will be described in detail with reference to the drawings. (First Embodiment) The configuration of an image reading apparatus to which the present invention can be applied is the same as that of FIG. 6 described above. As the image reading method, two methods, a scan reading method and a flowing reading method, are used.

That is, in FIG.
The document 17 placed on one document tray 12 is transported by the paper feed separation unit 13, electrostatically attracted to the document moving belt 14, and transported to a predetermined position on the document table glass 1.

An original image, which is illuminated by an illumination lamp 3 disposed on a first mirror base 2 as a scanning optical unit and reflected by the illumination lamp 3, is reflected by a first mirror similarly disposed on the first mirror base. 4 is reflected by the second and third mirror bases 5. Then, the light is reflected by the second mirror 6 and the third mirror 7 and condensed by the lens 8 to form an image on the light receiving surface of the CCD sensor 9 provided as a reading element.

The first mirror base 2 and the second and third mirror bases 5 are supported by rails (not shown), and are movable in the directions of the arrows as the optical motor 10 rotates.
A stepping motor is used as the optical motor 10 and is driven by a current supplied from an optical motor driver board (not shown). When the image reading on the platen glass 1 is completed, the sheet is immediately conveyed to the sheet discharging roller 15 by the document conveying belt and discharged to the document tray by the sheet discharging roller 15.

As the image reading method, two methods, a scan reading method and a flow reading method, are used. The scan reading method is configured to read an image by fixing a document on a document glass and moving a scanning optical system. On the other hand, the flow reading system is configured such that the scanning optical system is fixed and an image is read by moving a document with a document moving belt.

Further, in the case of a high-speed image reading device,
The CCD 9 has a resolution of 400 dpi, and the moving speed of the scanning optical system is the readable speed of the CCD 9.
It is configured to be movable at 40 mm / s.

The optical system has a reading speed of 540 mm /
s sufficient S / D at a resolution of 400 dpi of the CCD 9
N is obtained. Further, since the LTR original (sub-scanning size 216 mm) is configured to be able to read an image at an original spacing of 144 mm using a flowing scanning method, the number of originals read per unit time is 540 / (216 + 144) = 1. It is 5 sheets / s, and has an original reading speed of 90 cpm.

On the other hand, in the case of a high quality image reading device,
The CCD has a resolution of 600 dpi, and the moving speed of the scanning optical system is 360, which is the readable speed of the CCD.
It is configured to be movable at mm / s. The optical system has a reading speed of 360 mm / s and a CCD resolution of 600 mm.
The configuration is such that a sufficient S / N is obtained at dpi.

Further, the LTR original (sub-scanning size 216
mm) using the flow reading method, and a document interval of 144 m
m, the number of originals read per unit time is 360 / (216+
144) = 1 sheet / s, and has a document reading speed of 60 cpm.

The scan reading system is configured to read an image by fixing a document on a document glass and moving a scanning optical system. In addition, the flow reading system uses a scanning optical system, and is configured to read an image by moving a document with a document moving belt.

On the other hand, the CCD 9 has a resolution of 600 dpi and 300 dpi.
It is configured to be usable at a resolution of pi. And. When used at a resolution of 600 dpi, the driving clock of the CCD driver is set to 30 MH, and a data transfer speed corresponding to the scanning speed is obtained.

When using at a resolution of 300 dpi, the driving clock of the CCD driver is set to 15 MH, so that a data transfer speed corresponding to the scanning speed can be obtained. Furthermore, depending on the resolution used, the CCD 9
Is configured to be able to switch the drive clock of

When the CCD 9 is used at a resolution of 600 dpi, the moving speed of the scanning optical system moves at 360 mm / s for scanning and reading, and the original feeding speed of the original feeder also becomes 360 mm for scanning reading. / S
It is configured to be movable.

When the CCD 9 is used at a resolution of 300 dpi, the moving speed of the scanning optical system moves at one 360 mm / s, and the document feeding speed of the document feeder is 360 mm / s.
And can be read at a relative speed of 720 mm / s.

Further, the optical system has a reading speed of 360 mm.
/ S is sufficient for 600 dpi resolution of CCD9
/ N is obtained. The optical system has a reading speed of 720 mm / s and a resolution of CCD 9 of 300 mm.
The configuration is such that a sufficient S / N is obtained at dpi.

However, in order to read an LTR original (sub-scanning size of 216 mm) at 60 × 2 = 120 cpm, an original transport speed of 216 × 2 = 432 mm / s or more is required. Therefore, the original conveyance speed is 360 mm /
s, the moving speed of the optical system is set to −360 mm / s, and the reading start position is sequentially moved upstream in the document conveying direction, so that the document is read at every minority by the document reading speed 72.
At 0 mm / s, it is configured so that productivity equivalent to 120 cpm can be obtained.

For this purpose, the size of the reading section made of the original glass in the original transport direction is 216 mm × 2 = 4.
It has a document reading speed of 32 mm or more.
This allows the optical system to read 21 originals.
Since 6/2 = 108 mm or more is required, 460/1
08 = 4.2, and 120 cpm for at least 4 sheets
It is configured to provide considerable productivity.

In the case of four or more sheets, the above operation is repeated by returning the optical system to the downstream side in the document conveying direction again. Accordingly, the number of sheets read per unit time is 360/216 = 1.6 sheets / s, so that a productivity of 90 cpm can be realized.

FIGS. 1 and 2 are flowcharts illustrating the image reading operation of the image reading apparatus according to the present embodiment. When the user sets a document on the document tray of the document feeder, the document detection sensor of the document stacking tray detects this. Then, in the next step S2, <select resolution> is displayed on a display unit (not shown).

The image reading apparatus of the present embodiment is provided with a selection button for a high resolution and a normal resolution on an operation unit (not shown), so that the user can select a resolution according to the display. .

It is determined in step S3 whether or not the user has selected the normal resolution, and it is determined in step S4 whether or not the user has selected the high resolution. As a result of the above determination, if the user selects high resolution, the process proceeds to step S5, where
In the reading mode of No. 9, 600 dpi is selected.

Next, the process proceeds to step S6, where <copying is possible> is displayed on a display unit (not shown), and the user is notified that copying is possible. Then, when the user presses the copy button of the operation unit (not shown), this is detected in step S7, and the document feeder starts the paper feed separation operation. At the same time, the first mirror base 2 is moved to and held at the sink reading unit (step S8).

Then, the original is transferred to the original by the original feeder.
While being conveyed at 0 mm / s, an image is read at 600 dpi. When the image reading is completed, the first document is discharged to the document tray by the document feeder.

Next, in step S10, it is determined whether or not there is a document on the document tray. If there is a document, the process proceeds to step 12, where the first mirror base 2 is moved to the raised position and held. I do.

On the other hand, if the result of determination in step S10 is that there is no original on the original tray, it is detected by a recycle lever (not shown), and the last sheet is detected. Based on this information, the process proceeds to step S11, in which the first mirror base 2 is moved to the home position and is in a standby state at the home position, and the document feeder is also in a standby state after finishing discharging the last sheet to the document tray. The processing of the second and subsequent documents is a repetition of the above-described processing.

On the other hand, as a result of the determination in step S3, when the normal resolution is selected, the processing shifts to step S21 shown in the flowchart of FIG. 2, and the reading mode of the CCD 9 is selected as 300 dpi. At this time, the amount of charge stored by photoelectric conversion per pixel of the CCD 9 is as follows:
It decreases because it is twice.

Therefore, in this embodiment, 600d
By using a sensor having a resolution of 300 dpi at 300 dpi, high-speed reading can be realized with the same light sensitivity.

Next, in step S22, <can be copied> is displayed on the display unit (not shown), and the user can operate the copy button of the operation unit (not shown). When the user presses the copy button, step S
23.

Then, in step S24, the document feeder starts the paper feed separation operation. At the same time, the first mirror base 2 is moved to the raised position and held. Next, the original is fed to the original feeder to make the original
The optical system moves at 360 mm / s,
The image is read at 0 dpi. When the image reading is completed, the first document is discharged to the document tray by the document feeder.

Next, in step S26, it is determined whether or not there is a document on the document tray. If there is a document, the process proceeds to step 28, where the first mirror base 2 is moved to the raised position and held. I do.

On the other hand, if the result of determination in step S26 is that there is no original on the original tray, it is detected by a recycle lever (not shown), and the last sheet is detected. Based on this information, the process proceeds to step S27, in which the first mirror base 2 is moved to the home position and is in a standby state at the home position, and the document feeder is also in a standby state after finishing discharging the last sheet to the document tray. The processing of the second and subsequent documents is a repetition of the above-described processing.

Based on this information, after the image reading of the last sheet is completed, the standby state is established at the home position on the mirror table, and the document feeder also enters the standby state after finishing discharging the last sheet to the original tray.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
1 is a cross-sectional view illustrating a schematic configuration of an image reading device to which the embodiment is applied. As shown in FIG. 3, in the image reading apparatus according to the present embodiment, a document 17 placed on a document tray 12 of a document feeder 11 is conveyed by a paper feed separation unit 13 and electrostatically attracted to a document moving belt 14. Then, it is conveyed onto the original table glass 1.

The original image illuminated by the illumination lamp 3 arranged on the first mirror base 2 as a scanning optical unit is converted into a second image by the first mirror 4 also arranged on the first mirror base 2. 3) Reflected to the mirror base 5.

Then, the light is reflected by the second mirror 6 and the third mirror 7, condensed by the lens 8, and is imaged by the CCD 9 as a reading element. The first mirror base and the second and third mirror bases are supported by rails (not shown), and are movable in the directions of the arrows as the optical motor 10 rotates.

In the present embodiment, a stepping motor is used as the optical motor 10 and driven by a current supplied from an optical motor driver board (not shown). In the one-sided document reading, when the image reading on the document table glass 1 is completed, the document is immediately discharged to the document tray by the discharge roller 15 by the document conveying belt. At this time, the document is guided between the transport belt roller B and the reverse belt roller C by the reversing flapper 20, and is guided to the discharging roller by the discharging flapper 19.

On the other hand, in the case of double-sided document reading, when the one-sided image reading on the document table glass is completed, the document is guided to the reversing path by the document conveying belt and immediately conveyed again to the document table glass.

At this time, the original is guided between the conveying belt roller B and the reversing belt roller C by the reversing flapper 20, and the reversing belt roller D is
And is guided again by the reversing flapper 20 onto the platen glass.

Further, when the reading of the double-sided image on the platen glass 1 is completed, the mark is conveyed by the document conveying belt, and
The sheet is guided between the transport belt roller A and the transport roller E by the double-sided discharge flapper 16. Thereafter, the sheet is conveyed to a sheet discharging roller by a conveying belt and discharged.

As the image reading method, two methods, a scan reading method and a flow reading method, are used. In the scan reading method, an image is read by fixing a document on the platen glass 1 and moving a scanning optical system. In the flow reading method, an image is read by fixing a scanning optical system and moving a document with a document moving belt.

On the other hand, the CCD 9 has a resolution of 600 dpi and 400 dpi.
It is configured to be usable at a resolution of pi. When using at a resolution of 600 dpi, the driving clock of the CCD driver is set to 30 MH, and a data transfer speed corresponding to the scanning speed is obtained.

Further, when using at a resolution of 400 dpi, the driving clock of the CCD driver is set to 20 MH, and in this case also, a data transfer speed corresponding to the scanning speed can be obtained.

Further, the configuration is such that the driving clock of the CCD 9 can be switched according to the resolution used. When the CCD 9 is used at a resolution of 600 dpi, the moving speed of the scanning optical system moves at 360 mm / s for scanning and reading, and the document conveying speed of the document feeder also moves at 360 mm / s for scanning reading. It has a movable configuration.

On the other hand, when the CCD 9 is used at a resolution of 400 dpi, the moving speed of the scanning optical system is -1.
The document feeder moves at 80 mm / s, and the document feed speed of the document feeder can move at 360 mm / s.

The reading speed of the optical system is 360 m.
At a speed of m / s, a sufficient S / N is obtained when the resolution of the CCD 9 is 600 dpi. The optical system is configured so that the reading speed is 540 mm / s and a sufficient S / N is obtained at a resolution of 400 dpi of the CCD 9.

Further, the LTR original (sub-scan size 216
mm), and the document spacing is 24 mm
, The number of documents read per unit time is 360 / (217 + 2).
4): 1.5 sheets / s, and has an original reading speed of 90 cpm.

FIG. 4 is a flowchart showing the procedure of the one-sided image reading operation, which corresponds to the flowchart of FIG. 2 in the image reading operation described with reference to FIGS. 1 and 2, and the processing procedure corresponding to FIG. 1 is omitted in this embodiment.

When the one-sided image reading operation is started, the reading mode of the CCD 9 is set to 40 in step 41.
0 dpi is selected. At this time, the amount of charge stored by photoelectric conversion per pixel of the CCD 9 decreases because the scan speed is 1.5 times.

Therefore, in this embodiment, 600 dp
By using a sensor having a resolution of i and a resolution of 400 dpi, high-speed reading can be realized by making the light sensitivity the same.

When the resolution is selected, the process proceeds to step S42, in which <can be copied> is displayed on the display unit (not shown), and the user can operate the copy button of the operation unit (not shown). When the user presses the copy button, this is detected in step S43, and in the next step S44, the document feeder starts the paper feed separation operation. At the same time,
The first mirror base 2 is moved to the rising position and held.

Next, in step S45, at the same time as the original is conveyed at 360 mm / s by the original feeder, the first mirror base 2 is accelerated to a scanning speed of -180 mm / s, and the original and the mirror base are moved together. 540 mm relative speed
/ S performs image reading at 400 dpi. When the reading is completed, the first document is discharged onto the document tray by the document feeder.

Next, in step S46, it is determined whether or not there is a document on the document tray. If there is a document, the process proceeds to step S48, where the first mirror base 2 is moved to the raised position and held. I do.

On the other hand, if the result of determination in step S46 is that there is no document on the document tray, it is detected by a recycle lever (not shown), and it is detected that it is the last sheet. Based on this information, the process proceeds to step S47, in which the first mirror base 2 is moved to the home position and is in a standby state at the home position, and the document feeder is also in a standby state after finishing discharging the last sheet to the document tray. The processing of the second and subsequent documents is a repetition of the above-described processing. When the final document is fed and separated, it is detected by the recycle lever,
The last sheet is detected.

According to the last sheet information, the mirror stand is in the standby state at the home position after the image of the last sheet is read, and the document feeder is also in the standby state after the discharge of the last sheet to the document tray.

FIG. 5 is a flowchart showing the procedure of the double-sided image reading operation. Also in this case, as described above, this is a portion corresponding to the flowchart of FIG. 2 in the image reading operation described with reference to FIGS. 1 and 2, and the processing procedure corresponding to FIG. 1 is the same as that of FIG. It is omitted in the embodiment.

When double-sided image reading is selected, the reading mode of the CCD 9 is set to 400 in step S51.
dpi is selected. At this time, the amount of charge stored by photoelectric conversion per pixel of the CCD 9 decreases because the scan speed is 1.5 times.

Therefore, in this embodiment, 600 dp
By using a sensor having a resolution of i at 400 dpi, high-speed reading can be realized by making the light sensitivity the same.

When the resolution is selected, in step S52, <can be copied> is displayed on the display unit (not shown), and the user can operate the copy button of the operation unit (not shown).

When the user presses the copy button, this is detected in step S53, and then in step S54, it is determined whether the copy start button has been pressed. If the result of this determination is that the copy start button has been pressed, then the process proceeds to step S55, where the document feeder starts a paper feed separation operation. At the same time, the first mirror base 2 is moved and held to the rising position.

Next, in step S56, the first mirror base 2 is accelerated to a scanning speed of -180 mm / s at the same time that the original is conveyed at 360 mm / s by the original feeder, and 540 mm relative speed
/ S performs image reading at 400 dpi.

Next, in step S57, the document is reversed by the reversing belt and transported to the image reading unit again.

Next, in step S58, at the same time as the original is conveyed at -360 mm / s by the original feeder, the first mirror base 2 is accelerated to a scanning speed of 180 mm / s, and the original and the mirror base are moved together. 540 mm relative speed
/ S, the CCD scans the image at 400 dpi, and then the first document is discharged to the document tray by the document feeder.

When the reading of the image is completed, the first document is discharged to the document tray by the document feeder, and the second document is conveyed. During this time, the first mirror table 2 is back-scanned to the rising position, and starts scanning in synchronization with the second document. This is repeated for the second and subsequent sheets.

Next, in step S59, it is determined whether or not there is a document on the document tray. If there is a document, the flow advances to step S61 to move the first mirror base 2 to the raised position and hold it. I do.

On the other hand, if the result of determination in step S59 is that there is no original on the original tray, it is detected by a recycle lever (not shown), and the last sheet is detected. Based on this information, the process proceeds to step S60, in which the first mirror base 2 is moved to the home position and is in a standby state at the home position, and the document feeder is also in a standby state after finishing discharging the last sheet to the document tray. The processing of the second and subsequent documents is a repetition of the above-described processing. When the final document is fed and separated, it is detected by the recycle lever,
The last sheet is detected.

According to the last sheet information, the mirror stand is in the standby state at the home position after reading the image of the last sheet, and the document feeder is also in the standby state after discharging the last sheet to the document tray.

FIG. 7 is a diagram showing an example of a computer system constituting the above-described image reading apparatus. FIG.
, 1200 is a computer PC. PC1
200 includes a CPU 1201 and is stored in a ROM 1202 or a hard disk (HD) 1211 or a floppy (registered trademark) disk drive (FD).
By executing the control software supplied from the unit 1212, each device connected to the system bus 1204 is comprehensively controlled. CPU 1201, ROM 12 of PC 1200
02 or a program stored in the hard disk (HD) 1211 executes each process of the present embodiment.

Reference numeral 1203 denotes a RAM, which functions as a main memory, a work area, and the like for the CPU 1201. Reference numeral 1207 denotes a disk controller (DKC), which is a hard disk (HD) 1211 for storing a boot program (starting program: a program for starting execution (operation) of personal computer hardware and software), a plurality of applications, user files, a network management program, and the like. , And a floppy disk (FD) 1212.

Reference numeral 1208 denotes a network interface card (NIC), which is connected via a LAN 1220 to a network printer, another network device, or another PC.
It exchanges data bidirectionally with C.

(Other Embodiments of the Present Invention) The present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but is also applicable to an apparatus composed of one device. You may.

Further, the functions of the above-described embodiment are implemented in an apparatus connected to the above-described various devices or a computer in a system so that various devices are operated so as to realize the functions of the above-described embodiment. Supplies the software program code for performing the
The invention implemented by operating the various devices according to the program stored in U) is also included in the scope of the present invention.

In this case, the program code of the software implements the functions of the above-described embodiment, and the program code itself and means for supplying the program code to the computer, for example, the program The storage medium storing the code constitutes the present invention. As a storage medium for storing such a program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-RO
M, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the supplied program code, not only the functions described in the above embodiment are realized, but also the OS (operating system) in which the program code runs on the computer. Alternatively, even when the functions described in the above-described embodiments are implemented in cooperation with other application software or the like, it goes without saying that such program codes are included in the embodiments of the present invention.

Further, after the supplied program code is stored in the memory provided in the function expansion board of the computer or the function expansion unit connected to the computer, the function expansion board or the function expansion unit is specified based on the instruction of the program code. The present invention also includes a case where a CPU or the like provided in the apparatus performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0094]

According to the present invention, in an image reading apparatus for illuminating a document and receiving reflected light thereof and performing photoelectric conversion to generate an image signal, the resolution for reading the document is D (dpi). When the original reading speed at that time is V (mm / s), D * V = N
The document reading speed V is controlled in accordance with the document reading resolution D so that (N: an arbitrary constant), so that the productivity according to the image quality while maintaining the same S / N as in the related art. Can be provided. For this reason, for example, when a CCD of about 600 dpi is used, by improving the performance of the optical system little by little, the cost increase can be minimized, and the significant cost increase can be suppressed.
For a document requiring a high resolution, it is possible to read a 600 dpi high resolution image with the same productivity as the conventional one. Also, when high productivity is required, high single-sided productivity can be achieved at 400 dpi, which is the same resolution as the conventional one, and the demand for high image quality and high productivity can be achieved with one device at low cost. Can be provided. Further, since the document feeding accuracy is the same, a stable accuracy higher than the paper conveyance accuracy can be obtained only by improving the moving accuracy of the scanning optical system. Further, it is possible to suppress an increase in the jam occurrence rate of the document feeder, and it is possible to improve the lifetime productivity of the image reading device. Further, for a two-sided original, the scanning movement direction of the scanning optical system and the original movement direction of the original movement system are set to opposite directions, and the scanning movement direction of the scanning optical system and the original movement when reading the first side and the second side of the two-sided original are read. Since the original movement direction of the system is set to the opposite direction,
While keeping the original conveyance speed at the same resolution as before,
High double-sided productivity is obtained. In addition, since the influence of the deterioration of the document feeding accuracy and the jam of the document feeding device can be reduced, the lifetime productivity of the image reading device can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an image reading operation according to a first embodiment of the present invention.

FIG. 2 is a flowchart of an image reading operation according to the first embodiment.

FIG. 3 is a cross-sectional view illustrating a main configuration of an image reading apparatus to which a second embodiment of the present invention has been applied.

FIG. 4 is a flowchart illustrating a single-sided image reading operation, illustrating an operation procedure of the image reading apparatus according to the second embodiment.

FIG. 5 is a flowchart illustrating an operation procedure of the image reading apparatus according to the second embodiment, which is a double-sided image reading operation.

FIG. 6 is a cross-sectional view illustrating a general configuration of an image reading apparatus to which the present invention can be applied.

FIG. 7 is a block diagram illustrating an example of a computer system constituting control means of an image reading apparatus to which the present invention can be applied.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 platen glass 2 first mirror stand 3 illumination lamp 4 first mirror 5 second / third mirror stand 6 second mirror 7 third mirror 8 lens 9 CCD sensor 10 optical motor 11 document feeder 12 document tray 13 Paper feed separation unit 14 Document moving belt 15 Discharge roller 16 Double-sided discharge flapper 17 Document

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H04N 1/17 H04N 1/12 A F term (Reference) 2H076 AA35 AA58 BA24 BA27 BA42 BA58 BA68 BA83 2H108 AA17 CB01 FA05 FA21 FB00 FB16 FB41 5B047 AA01 BA02 BB02 CA08 CB10 5C062 AA05 AB17 AB32 AC02 AC09 AC12 5C072 AA01 BA05 BA16 MB02 MB04 WA02

Claims (12)

[Claims] 1. An image reading apparatus for illuminating a document, receiving reflected light thereof, and performing photoelectric conversion to generate an image signal, wherein the resolution for reading the document is D (dpi), and the document reading speed at that time is Is V (mm / s), D
An image reading apparatus wherein the document reading speed V is controlled in accordance with the document reading resolution D such that V = N (N: an arbitrary constant). 2. The apparatus according to claim 1, wherein the document reading speed V is a difference (V1-V2) between a sub-scanning speed V1 of the scanning optical system and a document moving speed V2 of the document moving system. Image reading device. 3. The image reading apparatus according to claim 1, wherein a scanning movement direction of the scanning optical system and a document movement direction of the document movement system are set in opposite directions. 4. The image reading apparatus according to claim 1, wherein a reading start position of the document is sequentially moved to an upstream side in a direction in which the document moves. 5. When reading the original, the scanning movement direction of the scanning optical system and the original movement direction of the original movement system are
5. The image reading apparatus according to claim 4, wherein the directions of reading the first side and the second side of the double-sided document are opposite to each other. 6. An image reading method for illuminating a document, receiving reflected light thereof, and performing photoelectric conversion to generate an image signal, wherein the resolution for reading the document is D (dpi), and the document reading speed at that time is D (dpi). Is V (mm / s), D
* An image reading method, wherein the document reading speed V is controlled in accordance with the document reading resolution D such that V = N (N: an arbitrary constant). 7. The apparatus according to claim 6, wherein the document reading speed V is a difference (V1−V2) between a sub-scanning speed V1 of the scanning optical system and a document moving speed V2 of the document moving system. Image reading method. 8. The image reading method according to claim 6, wherein the scanning movement direction of the scanning optical system is opposite to the document movement direction of the document movement system. 9. The image reading method according to claim 6, wherein a reading start position of the document is sequentially moved to an upstream side in a moving direction of the document. 10. When reading the original, the scanning movement direction of the scanning optical system and the original movement direction of the original movement system are set in opposite directions when reading the first side and the second side of the double-sided original, respectively. The image reading method according to claim 9, wherein: 11. A storage medium storing a program constituting each means according to claim 1 so as to be readable from a computer. 12. A storage medium storing a program for executing the image reading method according to claim 6 so as to be readable from a computer.