JP2002232646A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader capable of improving image quality in regard to intermittent reading by efficiently using a storing means (memory means) for image information in an image scanner capable of reading both faces. SOLUTION: This image reader having a first reading means for reading an image from one face of an original, a second reading means for reading an image from the other face of the original, a first storing means for storing image data prepared by the first reading means, and a second storing means for storing image data prepared by the second reading means, predicts the amount of data of image data to be prepared when reading the image by using only the first reading means and stores the image data in the second storing means when the amount of data surpasses the storage capacity of the first storing means.

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 capable of reading information on both sides of a document almost simultaneously, and more particularly, to reading the front and back surfaces of a document by separate reading means and storing image data. The present invention relates to control of an image reading device such as an image scanner, a facsimile, and a copying machine when an apparatus reads only one side of a document.

[0002]

2. Description of the Related Art In recent years, with the spread of computers, the sharing of information, the efficiency of the search business, and the use of OA such as electronic documentation have been rapidly progressing, electronic filing systems having an image scanner (image reading device) have been widely used. Is being used. In this system, the image reading device is used as a powerful input device for digitizing data of a conventional printed matter or the like. Therefore, an extremely large number of document manuscripts may be converted into electronic documents using a scanner. Therefore, in order to increase the work efficiency of this system, it is always required to increase the speed of the image reading device.

On the other hand, the image reading apparatus needs to process not less than a document having image information on both sides, that is, a so-called double-sided document. It is required to read an image at the same time.

Conventionally, most of the image scanners are so-called flat-bed type apparatuses, in which an original is placed and fixed on a glass surface and read while moving an optical system along the original surface. However, in order to realize the above-described double-sided image reading, a so-called original transport type image scanner, in which an optical system is stopped and fixed to read an image while transporting an original, is becoming widespread.

[0005] Further, there has been proposed an image reading apparatus capable of reading a double-sided image by having a mechanism for conveying and reversing a document. However, this image reading apparatus must be provided with a document reversing mechanism, and is therefore extremely large.

In order to read both the front and back sides of an original, there has been proposed an image scanner in which individual reading means are provided on the front and back sides, respectively. According to this, since a document reversing mechanism is not required, it is possible to read images on both sides of the document by one-time document transport, and thus it is possible to meet the demand for downsizing and high-speed operation. Also, in this image reading apparatus, separate reading means corresponding to the front and back of the document are provided, so that a storage means (memory means) for temporarily storing read image data is provided for two sides of the document. Become. This makes it possible to read images on both sides of the document by one transport of the document.

Here, the image reading apparatus is also required to have high image quality. However, when an image on a document is read at a high resolution, the amount of image data to be read increases, but when writing of read data to a finite amount of buffers catches up with data retrieval from the finite buffer, the reading operation is performed. Must be stopped once. Reading and writing data from and to this finite amount of buffers depends on a predetermined transfer rate determined by an external interface connected to the image scanner. That is, since the original is read at a high resolution in order to obtain high image quality, the operation of reading the original may be an intermittent operation. Since reading cannot be performed continuously, image quality may be affected.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of these requirements, and has been made in consideration of the above circumstances. It is an object of the present invention to provide an image reading device capable of improving the image quality of the image reading device.

[0009]

In order to achieve the above object, an image reading apparatus according to the first aspect of the present invention comprises a first reading means for reading an image from one side of a document,
A second reading unit that reads an image from the other side of the document, a first storage unit that stores image data created by the first reading unit, and a storage unit that stores image data created by the second reading unit. And a second storage unit that reads the image using only the first reading unit, and estimates the data amount of the image data to be created. Is larger than the capacity of the first storage means, the image data is stored in the second storage means.

According to a second aspect of the present invention, in the image reading apparatus of the first aspect, the first storage means has a smaller storage capacity than the second storage means.

[0011] The invention according to claim 3 is the invention according to claim 1 or 2.
The image reading apparatus according to the above, further comprising a third image reading means for reading the document at a position different from that of the first reading means.

The invention according to claim 4 is the first or second invention.
Wherein the first image reading means is capable of reading an image at a plurality of positions.

According to a fifth aspect of the present invention, in the image reading apparatus according to any one of the first to fourth aspects, the data amount of the image data is calculated based on a reading condition set by a user. .

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an example of the overall configuration of an image reading apparatus according to the present invention.

The original placed on the original platen glass 1 is
The illumination is performed by an illumination lamp 3 integrally formed with the mirror 2. This reflected light is scanned by the first mirror 2 and the second and third mirrors 4 and 5 which are integrally formed. Thereafter, the reflected light is converged by the lens 31 and is irradiated on the CCD 6 to be photoelectrically converted. Note that the first mirror 2, the illumination lamp 3, the second mirror 4, and the third mirror 5 may be configured to be movable in the direction A shown in FIG.

The originals stacked on the original tray 8 are
The pickup roller 9, the registration roller pair 10, the conveyance drum 11, and the conveyance roller 12 pass through the reading position B, and then the conveyance roller pair 13, and the discharge roller pair 1
4 and is discharged onto the discharge tray 32. The manuscript is
When passing through the reading position B, it is irradiated by the illumination lamp 3 installed near the reading position B.

The reflected light is scanned by the first mirror 2 and the second and third mirrors 4 and 5 which are integrally formed. Thereafter, the light is converged by the lens 31 and is irradiated on the CCD 6 to be photoelectrically converted. Note that the pickup roller 9 and the registration roller pair 10 are driven by a paper feed motor (not shown),
2, transport roller pair 13, and discharge roller pair 14
Is driven by a transport motor (not shown).

At the reading position C, the contact image sensor 1
5 is arranged. The contact image sensor 15 includes an LED (not shown) as a light source, a lens, a sensor element, and the like as constituent elements. When the document passes the reading position C, the opposite surface (back surface) read at the reading position B is irradiated by a lamp in the contact image sensor 15. The reflected light is converged by a lens on the contact image sensor 15 and is irradiated on a sensor element on the contact image sensor 15 to be photoelectrically converted. A white roller 17 is provided at an opposite portion of the contact image sensor 15 across the document, and is used as a white member for shading correction at the time of reading by the contact image sensor 15.

Further, the image reading apparatus may be configured as follows. Conveyance roller pair 13 and discharge roller pair 1
4, an endorser unit 18 and an endorser platen 19 are provided. The endorser 18 has a printing unit having a mark such as alphabetic characters and numerals impregnated with ink, and a pressure solenoid (not shown) for pressing the printing unit in the direction of the endor platen.
The original is stopped on the endorser 18, fixed in the pressing direction by the endorser platen 19, and
Is applied to the printing section, thereby printing alphabet letters and numbers on the document surface.

FIG. 2 is a block diagram showing the configuration of the image reading apparatus. The reflected light of the document that has entered the CCD 6 installed on the SBU 20 is converted into an analog signal having a voltage value according to the light intensity in the CCD 6. This analog signal is output from the CCD 6 while being divided into odd bits and even bits. Then, the dark potential portion is removed by an analog processing circuit (not shown) of the SBU 20, the odd bits and the even bits are combined, gain-adjusted to a predetermined amplitude, input to the A / D converter, and converted into a digital signal.

The digitized image signal is sent to the SCU 21
The NIPU 33 performs a correction such as a shading correction, a gamma correction, and an MTF correction, binarizes the data, and outputs a video signal together with a page synchronization signal, a line synchronization signal, and an image clock.

The video signal output from NIPU 33 is output to option IPU 26 via connector 34. The option IPU 26 performs predetermined image processing on the input video signal, and outputs it to the SCU 21.

The SCU 21 inputs this video signal to a selector (not shown). This selector also has N
The video signal input from the IPU 33 is also input. S
The option IPU 26 selects which of the CU 21 and the NIPU 33 performs image processing on the video signal input thereto.

The video signal output from the selector is transmitted to the SiB for managing the image data storage means (DRAM).
The data is input to C35 and stored in an image memory such as a DRAM. Then, the data is sent to the SCSI controller 36 and transferred to an external device such as a personal computer.

The analog image signal photoelectrically converted by the contact image sensor 15 is digitally converted on the RSBU 16. The digitized image signal is sent to the RCU 23 after being subjected to shading correction on the RSBU.

The RCU 23 has an image memory such as a DRAM and a SiBC for controlling the image data memory. The RCU 23 temporarily stores the image data in the image memory and then transfers the image data to the SCU 21. The image data sent from the RCU 23 to the SCU 21 and the image data output from the SiBC 35 on the SCU 21 are designed to be switchable.
Transfer to

On the SCU 21, a CPU 37, a ROM 3
8, RAM 39 and the like are mounted. The CPU 37
The CSI controller 36 controls communication with an external device such as a personal computer. In addition, it also performs timing control of the traveling body motor 7, which is a stepping motor, the sheet feeding motor, and the transport motor.

The ADU 30 is an automatic document feeder (AD)
It has a function of relaying the power supply of the electrical components used in the part F). An input port connected to the CPU 37 on the SCU 21 is connected to the main body operation panel 28 via the IOB 24. A start switch and an abort switch (not shown) are mounted on the main body operation panel 28. C
The PU 37 detects via the input port that each switch has been pressed by the user.

FIG. 3 is a block diagram schematically showing the principle configuration of the image reading apparatus. This image reading device has a first reading unit 301, a second reading unit 302, and a third reading unit 303. The first reading unit 301 reads image data on the front surface of the document 308. The second reading means 302
The first reading unit 301 reads a surface (back surface) different from the surface on which the document is read. The third reading means reads only one side of the document.

It should be noted that the first reading means 301 and the third reading means 303 may be the same, and the positions thereof may be moved depending on the reading mode. That is, when reading an image on a document while transporting the document, the first reading unit 301 performs a reading operation while fixing the document at a predetermined position. When reading a document fixed at a fixed position, the first reading means 301
Is read while scanning along the original as shown in FIG.

The first reading means 301 and the third reading means 303 are controlled in accordance with the reading operation mode required by the first reading control means 304. The second reading unit 302 includes a second reading control unit 3.
09.

The first reading means 301 and the second reading means 302 are each provided at the subsequent stage with the first image processing means 3.
05 and a second image processing means 306. First image processing means 305 and second image processing means 306
After performing necessary processing such as shading correction on the image data, outputs the image data to the first storage unit 310 and the second storage unit 311 and temporarily stores them.

The data transfer unit 307 acquires the image data stored in the first storage unit 310 and the second storage unit 311 as image data. Then, the data is transferred to the external interface at a predetermined transfer speed.

The first reading means 301, the second reading means 302, and the third reading means 303 are provided by a photoelectric conversion element represented by a CCD for reading image information on a document, and output from a photoelectric conversion element. An A / D converter for converting an analog signal to a digital signal, a light source for irradiating the surface of the original, and the like are included as constituent elements.

The first reading control means 304 and the second reading control means 309 include the first reading means 301,
A driving circuit for driving the photoelectric conversion element of the second reading unit 302 or the third reading unit 303, and a driving component for scanning the first reading unit 301 as the third reading unit 303, for example, a stepping motor; It includes a motor driver circuit and the like.

The first image processing means 305 and the second image processing means 306 perform various corrections such as shading correction, MTF correction, and γ correction, binarization / multi-value Various image processing such as conversion and error diffusion are performed.

The first storage means 310 and the second storage means 311 have memories for storing image data.
First reading means 301, third reading means 30
The image data read by the third or second reading means 302 and converted into a digital signal is written into this memory. The image data is read by the data transfer unit 307. Then, the data is transferred to the outside of the apparatus via an external interface at a predetermined transfer rate.

In the present description, the first storage means 310
And the memory capacity of the second storage means 311 are set as follows. Memory capacity of the first storage unit 310 A3 original (297 mm × 420 mm) is 400 dpi,
A capacity capable of storing one document (one page) as binary data, that is, ((297 mm / 25.4 mm) ×
400 dots) x ((420mm / 25.4mm) x
400 dots) 30.9 Mbit 4 MBytes
And Thus, even if the data transfer speed of the external interface is low, the first reading unit 301 or the third reading unit 303 can complete the reading operation without performing the intermittent reading operation. That is, in the case of reading an A3 document at 400 dpi and binarizing the image data and reading a document of a smaller size under similar reading conditions, it is not necessary to adjust the reading operation to the above data transfer speed. .

The intermittent reading will be described below.
The image reading apparatus temporarily stops the reading operation when the memory capacity becomes small, for example, when the writing of image data to a finite buffer (memory) catches up with the reading of image data from this buffer. That is,
When the buffer becomes nearly full, the reading operation is temporarily suspended until a certain amount of free space in the buffer is secured. When a certain amount of free space in the buffer is secured, the reading operation is restarted. Note that reading of image data from the buffer depends on the data transfer rate determined by the external interface connected by the data transfer unit 307. Such an operation is called intermittent reading.

On the other hand, the memory capacity of the second storage means 311 is 400 dp for an A3 original (297 mm × 420 mm).
Description will be made assuming that i has a capacity to store one document (one page) as multi-valued data. The data width of the image data in the present embodiment is 8 bits. Accordingly, the memory capacity of the second storage unit 311 in the present embodiment is ((297 mm / 25.4 mm) × 400 do.
ts) × ((420mm / 25.4mm) × 400do
ts) × 8 bits ≒ 247.5 Mbits ≒ 32 Mby
tes.

Therefore, the second reading means 302
Until image data obtained by reading one page of three originals at a reading density of 400 dpi is converted into multi-valued (8 bits / pixel), a reading operation can be performed without an intermittent operation. The reason why the memory capacity of the second memory means 311 is set to be larger than that of the first memory means 310 is as follows.
As shown in FIG. 5, during the double-sided reading operation, the image on the first side is read, the reading operation on the second side is started while the image is being transferred, and the image data is transferred to the external interface in a sequential manner. Because it is. That is, the second memory unit 311 needs to prepare a memory for the data amount corresponding to the readable size as the image memory of the second surface.

Next, the timing from reading of image data to data transfer will be schematically described with reference to FIG. FIG. 4 shows the timing of double-sided reading with a double-sided original.

The original is fed by the paper feeding means, passes over the read sensor 44, and passes through the front surface reading standby position 45. The front-side reading standby position 45 is a position for temporarily stopping the next document to be read when a plurality of documents are continuously read from the relationship between the transfer speed to the external interface and the document transport speed.

The original is placed at the front reading position 47 after a lapse of time t1 after passing through the front reading standby position 45. Then, reading of the front side of the document is started by the first reading unit 301.

The image data of the document surface read by the first reading means 301 is transferred to the first image processing means 3.
After the predetermined image processing is performed in step 05, the data is sent to the data transfer unit 307 and transferred to the external interface. The document is conveyed while being read by the first reading unit 301, and when it reaches the reading position 48 by the second reading unit 309, reading of the image data on the back surface of the document by the second reading unit 309 is started.

At this point, the data transfer means 307 has not yet finished transferring the image data of the front surface of the original which has been read to the external interface for the above-described reason. Therefore, the image data of the second surface (back side) of the document input from the second reading unit 309 is subjected to predetermined image processing by the second image processing unit 306, and then transferred to the data transfer unit 307. The data is temporarily stored in an image memory or the like under the control of the data transfer unit 307.

After the image data on the front side of the document has been transferred to the external interface, the data transfer means 307 starts transferring the image data on the back side of the document stored in the image memory to the external interface. In the present embodiment, the image data of the document surface read by the first reading unit 301 is transferred to the external interface in a so-called hanging state. Therefore, when reading a plurality of originals continuously, it is necessary to temporarily wait for the next original to be conveyed at the front surface reading standby position. In other words, it is necessary to wait until the data transfer unit 307 transfers all the image data on the back surface of the document by the second image reading unit 302 to the external interface.
This period is indicated by “Note” in FIG.

The period "t1" shown in FIG.
From the front surface reading standby position 45 to the reading position 47
It is the time until the manuscript reaches. “T2” is the time from the start of reading by the first reading unit 301 to the release of the obtained image data to the external interface. “T3” is the first reading means 301 of the document.
From the reading position 47 by the second reading means 302
Is the moving time to the reading position 48. "T4"
This is the time required for the second reading unit 302 to read the back side of the document. “T5” is the second reading means 30
2 is the time required until the image data on the back side of the document obtained in step 2 is released to the external interface.

The document presence sensor 52 shown in FIG.
This is a unit for detecting whether or not there is a document in the document tray of the ADF. The pickup roller 41 and the feed roller 42 are paper feeding means for feeding a document to a document carrying path of the ADF. The transport roller (transport drum) 51
It is a means for transporting inside the DF. The traveling body 46 is a part of the first reading unit 301 in which a light source for irradiating the surface of the original in the first reading unit 301 and a mirror are mounted. The tray-up sensor 49 is means for detecting a tray position used to lift a document tray on which documents are stacked to the paper feed port of the ADF or to lower the tray position for setting documents on the document tray. . The paper discharge sensor 50 is a detecting unit when the document is discharged from the ADF. Further, the feed sensor, the lead sensor, and the paper discharge sensor also detect a document feed jam in the ADF.

Next, FIG. 5 schematically shows the timing in the single-side reading mode. The basic operation is the same as the operation of reading both sides of a document using FIG. In the example shown in FIG. 5, the first reading unit 301 is fixed, and the document is conveyed to read the front surface image of the document. In addition,
FIG. 5 shows a timing chart for continuously reading originals.

Next, with reference to FIG. 6, the flow of a process for reading a one-sided document by the image reading apparatus according to the present invention will be described in detail.

First, the CPU of the image reading apparatus waits for an operation request from the host PC connected via the external interface (step S1). If there is an operation request (step S1 / YES), data relating to document reading conditions is received from the host PC (step S1).
2).

The CPU determines whether the original is read on one side or on both sides from the data (step S3).

In the case of the both-side reading mode (step S3)
/ YES), it is determined whether the reading operation mode requested by the host PC is high-resolution reading, binary reading or multi-value reading, and the necessary memory capacity is calculated from the information and the document size.

Here, the first storage means 31 in FIG.
0, the second storage means 311
Each of the storage capacities prepared in step (1) is grasped in advance, and this capacity is compared with the amount of image data obtained in the reading mode requested by the host PC (step S4).

The received data is stored in the first storage unit 310,
If it is determined that the data amount is larger than the capacity of the second storage unit 311 (step S4 / YES), a warning message is issued to the host PC (step S7). That is, the user is notified that an intermittent operation may occur during the reading operation, and the user is notified that there is a possibility that sufficient image quality may not be obtained.

With this warning, the user is prompted to select whether to execute reading in the already set reading mode or to change the reading conditions. That is, the host PC
Is notified of the content selected by the user.

When Changing Reading Conditions (Step S
In step 8), the process returns to step S2. If the reading condition is not changed (step S8 / YES), the switching unit 320 in FIG. 3 is moved to the A side (step S5), and the reading operation is performed (step S6).

When it is determined that the reading is not high-resolution reading, that is, the amount of image data obtained in the reading mode requested by the host PC is within the capacity of the first storage unit 310 and the second storage unit 311. If it is determined (step S4 / NO), the process proceeds to step S5.

If only one side of the document is to be read (step S3 / NO), a determination is made as to whether or not the reading condition requested in the same manner is high-resolution reading (step S9). . That is, the memory capacity required for image reading is calculated from information such as binary reading or multi-value reading, document size, and the like. Normally, in the case of single-sided reading, since the first reading unit 301 or the third reading unit 303 in FIG. 3 is used, in step S9, the memory capacity prepared for the first storage unit 310 is determined. Then, a comparison is made between the memory capacities required to realize the required reading conditions.

If the memory capacity of the first storage means 310 is larger than the required memory capacity (step S9 /
NO), switch the switching means 320 to the A side (step S)
5). If it is smaller (step S9 / YES), the switching unit 320 is moved to the B side (step S10). Thereafter, a reading operation is performed based on the requested reading operation condition (step S6).

In the image reading apparatus shown in FIG. 3, when double-sided reading of an original is selected, data transfer means (30)
7) The first storage unit 3 transfers the image data obtained to the external interface in a page-sequential manner.
10 and the reading of data from the second storage means 311 is controlled.

As described above, in the image reading apparatus having the both-side reading function, when reading the one-sided original,
By effectively utilizing the image processing system for reading the other side (back side of the original), it is possible to provide a single-sided image with higher quality. An image reading apparatus having a double-sided reading function can read both the front and back sides of a document at once. There are many usages that can be read at a high resolution in the read mode. Therefore, as described in the present embodiment, high-resolution reading can be realized by effectively utilizing the configuration for reading the back surface at the time of single-side reading, and the image quality required by the user can be handled by an efficient means. It becomes possible.

In other words, the image reading apparatus according to the present invention comprises: a document conveying means for conveying a document; and a first reading means for reading image information on a first surface of the document conveyed by the document conveying means. And a first processing unit for processing output data from the first reading unit.
Image processing means, first storage means for accumulating and storing output data from the first image processing means, and an image on a second surface different from the first surface of the original conveyed by the original conveyer A second reading unit that reads image information; and a second processing unit that processes output data from the second reading unit.
Image processing means, and second storage means for accumulating and storing output data from the second image processing means. The output data from the first image processing means is input to the first storage means. Switching means for switching between the input and the input to the second storage means.

This switching means is preferably controlled in accordance with a reading condition set by a user via a user interface. For example, the second storage means stores one of the originals readable by the second reading means.
When the first storage means has a storage capacity enough to store the image information for the surface, and the first storage means is smaller than the storage capacity of the second storage means, the output data from the first reading means is stored in the second storage means. By storing in the storage means, the problem of intermittent reading can be effectively solved. The reason why the problem of intermittent reading can be solved in this way is that the memory for storing the image data on the back side generally needs to be stored until the image data for the front side is output. This is because it is larger than the storage capacity. Therefore, the problem of intermittent reading can be extremely reduced by using the storage means for the back surface when reading the image of only the front surface, as compared with the case of using the memory for the front surface.

Note that a third reading means for reading the image information of the first side of the document at a position different from that of the first reading means may be provided. In this case, the first reading unit and the third reading unit may be the same reading unit.

Accordingly, an image reading apparatus capable of reading both sides of a document almost simultaneously can be realized, and the configuration of the second side at the time of reading the first side can be effectively utilized, and the image quality can be maintained. Becomes possible. In addition, the first reading unit and the third reading unit are the same reading unit, and by changing the reading position and the reading method (the operation method of the reading unit) of the document, the width of the type of the readable document can be increased. Becomes possible. In addition, it becomes possible to efficiently use the image memory according to the required reading conditions, and it is possible to improve the image quality due to the intermittent operation.

As described above, when reading an image on one side only, there is a possibility that the problem of intermittent reading may occur when the first storage means is used.
And / or when there is a possibility that the problem of intermittent reading may occur even when the second storage unit is used, the image data is read using both the first storage unit and the second storage unit. You may make it memorize | store. in this way,
As a method of treating a plurality of storage units as one storage unit, a known method can be adopted. Thus, the above description merely illustrates one embodiment of the present invention, and the present invention is not limited thereto.

[0069]

As is apparent from the above description, according to the first aspect of the present invention, in an image reading apparatus having two or more image reading means, when an image of only one side of a document is read, an intermittent operation is performed. Is extremely unlikely to occur,
It is possible to prevent a decrease in image quality due to the intermittent operation.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a configuration of an image reading apparatus according to the present invention.

FIG. 2 is a block diagram showing an internal configuration of the image reading device according to the present invention.

FIG. 3 is a configuration block diagram for explaining an operation of the image reading apparatus according to the present invention.

FIG. 4 is a diagram for explaining the operation of the image reading apparatus according to the present invention during double-sided reading.

FIG. 5 is a diagram for explaining the operation of the image reading apparatus according to the present invention at the time of single-sided reading.

FIG. 6 is a flowchart for explaining the operation of the image reading apparatus according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 platen glass 2 first mirror 3 illumination lamp 4 second mirror 5 third mirror 6 CCD 7 traveling motor 8 document tray 9 pickup roller 10 registration roller pair 11 transport drum 12 transport roller 13 transport roller pair 14 discharge roller pair 15 Contact Image Sensor 16 RSBU 17 White Roller 18 Endorser Unit 19 Endorser Platen 20 SBU 21 SCU 23 RCU 24 IOB 26 Optional IPU 28 Main Body Operation Panel 30 ADU 33 NIPU (Image Processing Unit) 34 Connector 35 SIBC 36 SCSI Controller ROM 37 CPU 37 39 RAM 40 Image memory (DRAM) 41 Pickup roller 42 Feed roller 43 Feed sensor 44 Read sensor 45 Surface reading Stand-by position 46 Traveling body 47 Front-side reading position 48 Back-side reading position 49 Tray-up sensor 50 Discharge sensor 51 Conveyance roller 52 Document presence sensor 301 First reading unit 302 Second reading unit 303 Third reading unit 304 First Reading control means 305 First image processing means 306 Second image processing means 307 Data transfer means 308 Document 309 Second reading control means 310 First storage means 311 Second storage means 320 Switching means 321 Control means

Claims (5)

[Claims] 1. A first method for reading an image from one side of a document
Reading means, second reading means for reading an image from the other side of the document, first storage means for storing image data created by the first reading means, and second reading means And a second storage unit for storing the image data created by the image reading device, wherein the image reading device is configured to read an image using only the first reading unit. An image reading apparatus for predicting a data amount of data, and storing the image data in the second storage means when the data amount exceeds the capacity of the first storage means. 2. The storage device according to claim 1, wherein the first storage unit has a smaller storage capacity than the second storage unit.
An image reading device according to claim 1. 3. The image reading apparatus according to claim 1, further comprising a third image reading unit that reads a document at a position different from the first reading unit. 4. The apparatus according to claim 1, wherein said first image reading means is capable of reading an image at a plurality of positions.
Or the image reading device according to 2. 5. The image reading apparatus according to claim 1, wherein the data amount of the image data is calculated based on a reading condition set by a user.