JPH11127310A - Image reader and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader having excellent reading accuracy capable of faithfully reading out an original image even at the time of executing connection reading. SOLUTION: During the stop of a mirror board, an orginal is moved up to a position B by a driving means in accordance with the control of a control means. Namely the mirror board is restarted from a position b1 and accelerated and a position a1 is aligned to a position c1 after a position arriving at an equal speed. Thereby the movement of the original during the stop of the mirror board is at least movement only by a distance adding a braking distance (an interval between a1 and b1 ) requird for speed reduction of the mirror board to an approach run distance (an interval between b1 and c1 ) necessary for acceleration in a direction reverse to the relative moving direction of the mirror board to be moved against the fixed original, i.e., the moving direction of the mirror board.

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 for reading an original image by an optical scanning member, and more particularly to an image reading apparatus and an image forming apparatus capable of transferring read image information to another apparatus. It is about.

[0002]

2. Description of the Related Art Conventionally, an image reading apparatus capable of transferring read image information to another apparatus includes, for example, a facsimile apparatus (FAX) and a modem. Image information transferred to another FAX, image information read by FAX to a computer or the like, or image information read by a modem to a computer or the like. Hereinafter, a brief configuration, operation, and the like of this type of image reading apparatus will be briefly described.

Such an image reading apparatus generally includes an automatic document feeder for sending a document image to an image reading unit, and the following two reading methods are available.

FIG. 4 is a schematic sectional view of the image reading apparatus.

The apparatus shown in FIG. 4A is a fixed-document type reading system, in which the original sent by the automatic original feeder 1 is stopped at a predetermined position, and the scanning optical member is moved to transfer the image. The apparatus shown in FIG. 4B is a document moving type reading method, in which the scanning optical member is stopped at a predetermined position and the automatic document feeder 2
To read the image by moving the original.

[0008] More specifically, first, in the fixed-document type reading method, the operator sets the bundle of documents S on the tray 3 with the side regulating member 11 together. Then, the paper feed roller 4 is rotated by the start signal, and the original is sent out. The sent original bundle S is separated one by one in the separation unit 5, and the leading end and the trailing end of the original are detected by the sensor 6. The sheet is fed to the conveying belt 7 driven by the driving pulley 12.

The original is stopped at a predetermined position on the original glass 13 in accordance with the detection timing of the sensor 6, and the mirror base 8 holding the light source scans in the direction of arrow 14 to read the original image of the original. Then, the read original is returned to the tray 3 through the paper discharge path 9 by the reverse rotation of the transport belt.

Next, in the original moving type reading method, the operator places the original bundle S on the tray 3 and places it on the side regulating member 11.
And set. Then, the feed roller 4 is rotated by the start signal to feed out the original, and the original bundle S is separated one by one in the separation unit 5, the leading end of the original is detected by the sensor 6, and the registration roller pair 16 and the discharge roller pair 17 are detected. Transported by At this time, the mirror table 8 holding the light source is fixed at a document reading position indicated by an arrow 15, and the document is read as the document passes through the position of the arrow 15. Documents that have been read are stacked on the paper discharge tray 10 by the paper discharge roller pair 17.

Also, there are two methods of transferring image data (image information) read by any of these methods to another device, a memory transmission method and a direct transmission method.

In a facsimile or the like, one of these two methods can generally be selected, and when the operator leaves the facsimile during transmission to send a plurality of original images, or when the transmission partner When it is convenient to use the memory transmission method when you want to proceed even when the communication line on the side is in use, and when you want to check each original image to be transmitted one by one It is convenient to use the direct transmission method. Hereinafter, these systems will be briefly described.

First, in the case of the memory transmission method, the read image data is temporarily stored in a memory, and thereafter,
Transmit the stored image data. At this time, depending on the original image, if the density or size of the original is large, the amount of image data may be too large and exceed the allowable storage amount of the memory.

In this case, when the memory capacity reaches the permissible amount, the reading of the document is interrupted, the transmission of the image data stored in the memory is performed, and the reading is started again when the memory becomes empty. Therefore, the image reading apparatus may repeatedly stop and start the scanning optical member or the document until reading of one document is completed.

Next, in the case of the direct transmission system, the read image is directly transmitted. At this time, if the document density is high, such as a photo document, the read image data amount may be too large and exceed the data amount that can be transmitted.

In this case, as in the case of the above-described memory transmission method, the reading is interrupted once to interrupt the transmission, and then the reading is started again. Therefore, in the image reading apparatus, reading may be performed by repeatedly stopping and starting the scanning optical member or the original.

Hereinafter, such a reading method is referred to as a continuous reading.

In order to perform the continuous reading, usually, in the case of a fixed original reading method, the scanning optical member is driven by a pulse motor or the like, and the pulse motor is controlled by a pulse as control means. It controls the movement and stop of the scanning optical member, and in the case of the original moving type reading method, the original conveying roller is driven by a pulse motor or the like, and the pulse motor is controlled by a pulse as a control means. This controls the movement and stop of the original.

[0017]

However, in this type of apparatus, when performing a continuous reading, even if a stop signal is input to a pulse motor as a driving source in order to temporarily suspend the reading, a constant speed state is obtained. It takes a very short time from the start to the stop state.

Therefore, the scanning optical member or the document requires a braking distance from a constant speed until it starts to decelerate and stops.

Also, a very short time is required at the time of starting the motor and before reaching the constant speed.

Therefore, a running distance is required until the scanning optical member or the document starts accelerating from the stopped state and reaches a certain speed.

Therefore, in particular, when high-speed reading is performed, the pulse motor starts in the self-starting area, accelerates to the through area, and when stopped, decelerates to the self-starting area and stops completely. Therefore, at the time of stopping and restarting, the read image may be stretched or the image may be omitted. Accordingly, blurring due to image omission and stretching occurs at the joint portion of the read image of the joint reading.

FIG. 5 schematically shows the occurrence of the blur in various cases. As described above, one of the scanning optical member and the original is fixed, and the other is moved, so that the reading scan is performed. The following description is based on the assumption that the mirror base, which is a scanning optical member, moves in the direction of arrow 19 (the original moves relatively in the opposite direction).

A single diagonal line is drawn on the original A fixed on the glass, and the mirror base scans in the direction of arrow 19 to read the image, and the image to be applied (the mirror base) Actually C in the read image
The image is read by a CD and then stored in a memory in the case of the above-mentioned memory transmission method, and is an image to be directly transmitted in the case of the above-mentioned direct transmission method). And E are shown separately.

First, the positional relationship between the original A and the reading unit using the mirror table when the continuous reading is performed will be described with reference to the original A in the drawing.

In the figure, the drive motor of the mirror base is a
At the points 1 and a2, a stop signal is received and the moving speed of the mirror base is reduced from V1 to 0. Then, the vehicle completely stops at points b1 and b2. That is, the interval between a1 and b1,
The distance between a2 and b2 is the braking distance.

After a predetermined time, upon receiving a start signal, the moving speed of the mirror base is accelerated from 0 to V1. From the point of c1, c2, the speed becomes constant (V1).
That is, the distance between b1 and c1 and the distance between b2 and c2 are the approach distances.

The read images B, C, D, and E are images obtained when the connection reading is performed, and each is a case where the form of the image read by the CCD is changed.

B shows the case where reading is continued during both deceleration and acceleration, and there is no image omission, but elongation occurs at portions a to c.

C indicates the case where the reading is continued only during acceleration, and the elongation due to the reading during acceleration and the dropout due to not performing the reading during deceleration occur. On the other hand, D indicates the case where reading is continued only during deceleration. In this case, an extension occurs due to reading during deceleration, and a dropout occurs due to non-reading during acceleration.

Further, E is a case where reading is performed only at a constant speed, and omissions occur in portions a to c.

As described above, in any case, the read image is blurred.

When the mirror base is started, the end of the read image tends to be blurred due to the vibration of the mirror base itself.

In practice, the distance required for acceleration and deceleration is
Although it is an area of 1 mm or less, the original blur appears remarkably in a diagonal original as shown in the figure or an original with fine characters.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to make it possible to read an image which is faithful to the original image even in the case of continuous reading. An object of the present invention is to provide an image reading apparatus having excellent accuracy.

[0035]

According to the present invention, there is provided a scanning optical member for reading an image by moving relative to an original image of an original having an image in a predetermined area, Control means for temporarily stopping the scanning optical member during the movement of a part of the predetermined area of the document image and then restarting the movement, and wherein the control means includes: When the relative movement with the scanning optical member is temporarily stopped, the relative movement is performed by a predetermined distance in a direction opposite to the relative movement.

Therefore, the area of the document image that is not properly read due to the stop of the relative movement between the document image and the scanning optical member is read again by the scanning optical member.

Preferably, the relative movement at the time of reading is a movement of the scanning optical member with respect to the fixing of the document, and the relative movement by a predetermined distance by the control means is a movement of the document with respect to the stopped scanning optical member.

Therefore, the scanning optical member moves with respect to the fixed document to read the document image, and the area of the document image that is not properly read due to the scanning optical member temporarily stopping during the reading is determined. By moving the document by that amount, this area is properly read again.

The relative movement at the time of reading is the movement of the original relative to the fixing of the scanning optical member, and the relative movement by a predetermined distance by the control means is the movement of the scanning optical member relative to the stopped original. it can.

Therefore, the original is moved with respect to the fixed scanning optical member, the original image is read, and the area of the original image that has not been properly read due to the temporary stoppage of the original during the scanning is determined. By moving the member by that amount, the area is read properly again.

When the amount of image information read by the scanning optical member reaches an allowable amount, a stop signal for temporarily stopping the relative movement between the document image and the scanning optical member may be sent to the control means.

Therefore, the image information to be read does not leak.

The predetermined distance for the relative movement of the scanning optical member in the opposite direction is the braking distance from when the scanning optical member starts to decelerate to when it stops, and the fixed distance when the scanning optical member starts accelerating to start moving. The distance may be a sum of the approach distance required to reach the speed.

Therefore, the image is moved by a distance corresponding to the area that is not properly read, so that all the image areas are properly read in the shortest time.

A storage means for storing image information read after the scanning optical member starts accelerating to start moving and at a constant speed and image information immediately before the scanning optical member starts decelerating. It is good to have.

Therefore, only the properly read portion is stored in the storage means.

Transmission means for transmitting image information read after the scanning optical member starts accelerating to start moving and reaching a constant speed and image information immediately before the scanning optical member starts decelerating. It is good to have.

Therefore, only the part that has been properly read is transmitted to the transmitting means.

[0049]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

First, the overall configuration of the image reading apparatus will be described with reference to FIG.

FIG. 4 is a schematic sectional configuration diagram of the image reading apparatus.

The apparatus shown in FIG. 4A is a fixed-document type reading system, in which the original sent by the automatic original feeder 1 is stopped at a predetermined position, and the scanning optical member is moved to transfer the image. The apparatus shown in FIG. 4B is a document moving type reading method, in which the scanning optical member is stopped at a predetermined position and the automatic document feeder 2
To read the image by moving the original.

More specifically, first, in the original-fixed-type reading method, the operator sets the original bundle S on the tray 3 together with the side regulating member 11. Then, the paper feed roller 4 is rotated by the start signal, and the original is sent out. The sent original bundle S is separated one by one in the separation unit 5, and the leading end and the trailing end of the original are detected by the sensor 6. The sheet is fed to the conveying belt 7 driven by the driving pulley 12.

The original is stopped at a predetermined position on the original glass 13 in accordance with the detection timing of the sensor 6, and the mirror table 8 holding the light source scans in the direction of the arrow 14, thereby reading the original image of the original. Then, the read original is returned to the tray 3 through the paper discharge path 9 by the reverse rotation of the transport belt.

Next, in the original moving type reading method, the operator places the original bundle S on the tray 3 and places it on the side regulating member 11.
And set. Then, the feed roller 4 is rotated by the start signal to feed out the original, and the original bundle S is separated one by one in the separation unit 5, the leading end of the original is detected by the sensor 6, and the registration roller pair 16 and the discharge roller pair 17 are detected. Transported by At this time, the mirror table 8 holding the light source is fixed at a document reading position indicated by an arrow 15, and the document is read as the document passes through the position of the arrow 15. Documents that have been read are stacked on the paper discharge tray 10 by the paper discharge roller pair 17.

Hereinafter, the case where the embodiment of the present invention is applied to the fixed original type reading system shown in FIG. 4A and the case where the original moving type reading system shown in FIG. The case where the embodiment of the present invention is applied will be described separately.

(First Embodiment) FIGS. 1 and 2 show an image reading apparatus according to a first embodiment of the present invention (in the case of a fixed original reading system).

FIG. 1 shows an embodiment of the present invention in the case where a continuous reading is performed in an image reading by an image reading apparatus which performs scanning by a mirror base as a scanning optical member as shown in FIG. 7 schematically shows a document reading position controlled by the control unit according to the embodiment.

With respect to the original image of the original set at the position A in the figure, the mirror table 8 starts scanning and reading in the direction of arrow 21 and receives a drive stop signal at the position a1. This is usually because the amount of image information read by the mirror base 8 has reached the allowable amount (in the case of the memory transmission method as described above, the memory capacity has reached the allowable amount, and the direct transmission method In this case, the amount of data that can be transmitted has been reached.)

Then, the mirror base 8 decelerates and stops at the position b1. That is, the distance between a1 and b1 is the braking distance.

Then, while the mirror base 8 is stopped, the original is moved to the position B in the figure by the driving means (pulse motor or the like) according to the control means (pulse or the like) not shown. That is, the mirror stand 8 is restarted from the position b1 and a1 is adjusted to the position c1 after the position where the mirror base 8 starts accelerating and reaches a constant speed. (Of course, the position where the speed reaches the constant speed may be set to c1; however, it is necessary to set the position to reach the constant speed sufficiently in consideration of the accuracy error, etc.). Is moved in the direction opposite to the relative movement direction of the mirror base 8 moving with respect to the fixed document, that is, in the direction in which the mirror base 8 was moving, at least the braking required for deceleration of the mirror base 8. The movement is a distance that is the sum of the distance (the distance between a1 and b1) and the approach distance (the distance between b1 and c1) required for acceleration. The case where the distance is equal to the sum of the braking distance and the approach distance is the shortest distance, in which case the loss is the smallest and the processing speed is the shortest.

Next, of the images read by the mirror table 8, the image actually read by the CCD (the image is stored in a memory in the case of the above-mentioned memory transmission method, and thereafter, is stored in the memory. Is transmitted directly in the case of).

First, after the mirror table 8 starts moving for the first time and reaches a constant speed, the CCD reading is started, and thereafter (or simultaneously) the reading section of the mirror table 8 reaches one end of the original image area, and The table 8 continues to move at a constant speed, and receives the drive stop signal at the position a1 as described above, and at the same time stops reading the CCD.

Therefore, the image of the area where the mirror base 8 is decelerating (the area from a1 to b1) is not read by the CCD. In the figure, only the shaded area from the left end to a1 is read.

Then, the mirror table 8 restarts from the position of b1, and starts accelerating and reaches a constant velocity (or at the same time as the constant velocity) and reaches c1 (a of the moved original a).
(Corresponding to 1), the CCD reading is started again.

Therefore, the image of the area where the mirror base 8 accelerates (the area included from b1 to c1) is not read by the CCD. In the figure, only the shaded area after a1 is read.

As described above, on the CCD side, the unstable area (the area which is read at the time of deceleration and acceleration which is not constant speed reading) in the image read by the mirror base 8 is not read, and the reading by the CCD is interrupted. Since the proper reading is started again from the set position (a1), the image read by the CCD is an image faithful to the original image without expansion or omission.

After that, the same control is performed when the second, third,... Stop signals are sent. C in the figure is 2
The position of the original that has moved after the second stop of the mirror stand 8 is the reading area, and the shaded areas a1 to a2 in the figure are the reading areas.
D in the figure is the position of the original which has moved after the third stop of the mirror stand 8, and the hatched areas a2 to a3 in the figure are the reading areas. As described above, even in the image obtained by performing the joint reading three times, as shown in FIG.
Read by D.

FIG. 2 is a diagram showing control of each part of the connection reading of FIG.

First, the mirror base 8 issues a drive ON signal (▽
Part), acceleration starts, and when the speed reaches V1, the speed becomes constant. Then, the reading of the CCD is turned on in accordance with the position of the leading edge of the document, and reading is started.

Then, at the point a1, the drive OFF signal (▼
), The CCD reading is also turned off at the same time.
The mirror base 8 decelerates to the speed 0, and accelerates to the point c1 at which the speed becomes V1 by the next ON signal. At this time, the mirror base 8 moves at a non-constant speed by a distance indicated by l in the figure. Therefore, while the mirror base 8 is stopped, the distance l
However, by advancing the original, it is possible to perform the continuous reading without reading in the non-constant speed area and without any missing area.

Further, in order to perform the joint reading by this method and to smooth the image of the joint portion, it is necessary to remove backlash due to the backlash or the like in the drive transmission path at the time of stopping or restarting the mirror table 8 and the original. In practice, a means such as transmitting drive from a motor by a belt is used.

As described above, in the present embodiment, it is possible to prevent blurring at the time of continuous reading by using the transport belt 7 of the document feeder shown in FIG.

Then, after the image faithful to the original image having no stretch or omission is read by the CCD, in the case of the above-mentioned memory transmission method, the image is stored in a memory and then transmitted by the transmission means (not shown). In the case of the direct transmission method, the image is read and transmitted directly by a transmitting unit (not shown).

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention. In the first embodiment, the case of the fixed original reading method is described, but in the present embodiment, the case of the moving original reading method is described.

Note that, also in the present embodiment, when the positional relationship between the mirror base as the scanning optical member and the original image of the original is viewed from the viewpoint of relative positional movement, the same as in the first embodiment. However, the present embodiment will be described below.

FIG. 3 shows an image reading by an image reading apparatus in which a document is moved and scanned with respect to a mirror table 8 as a fixed scanning optical member as shown in FIG. 4B. This is a diagram schematically illustrating a reading position of a document that is controlled by the control unit according to the present embodiment in a case where the continuous reading is performed.

As shown in FIG. 3, the relationship between the original conveyance and stop positions and the fixed position (part 部) of the mirror base 8 when the control according to the present embodiment is performed is shown.

The original is set at the position A in the figure with respect to the fixed position of the mirror base 8, is conveyed in the direction of the arrow 22, arrives at the 後 に portion after reaching a constant speed, and starts reading by the CCD. At the point a1, a signal to stop the document conveyance and stop reading by the CCD is issued (B), and the speed is reduced, and the document stops at the point b1 (C).

Here, the mirror base 8 moves to a point c1 in FIG. That is, the interval between c1 and a1 is the approach distance required until the document reaches the uniform speed after the document is restarted. When the document is restarted from the state of D in FIG. Has a constant speed, and can be read at a constant speed.

The movement of the mirror table 8 while the original is stopped is relatively similar to that of the first embodiment described above.
In the direction opposite to the relative movement direction of the original moving relative to the fixed mirror base 8 (part ▲), that is, in the direction in which the original was moving, at least the braking distance (a1 and The movement is a distance that is the sum of the distance between b1) and the approach distance required for acceleration (the distance between a1 and c1). The case where the distance is equal to the sum of the braking distance and the approach distance is the shortest distance, in which case the loss is the smallest and the processing speed is the shortest.

When the second document stop signal is received at a2 (E), the document stops at the point b2 (F), and the mirror table 8 moves to c.
Move to 2 (G).

As described above, in the continuous reading of the original scanning type image reading apparatus, on the CCD side, the unstable area (the area to be read at the time of deceleration and the time of acceleration other than the constant speed reading) of the image read by the mirror table 8 is the same. The position (a
Since the proper reading is started again from 1), the image read by the CCD can be read as an image faithful to the original image without stretching or missing.

In the present embodiment, the moving space of the mirror base 8 is only required to correct the error (that is, for example, the sum of the above-mentioned braking distance and running distance), so that it is suitable for downsizing the image reading apparatus. I have.

[0085]

According to the present invention, when the relative movement between the original image and the scanning optical member is temporarily stopped by the control means, the relative movement is performed by a predetermined distance in a direction opposite to the relative movement. Since the relative movement between the original image and the scanning optical member is temporarily stopped, the area of the original image that has not been properly read can be read again by the scanning optical member. And the reading accuracy is improved.

When the relative movement at the time of reading is defined as the movement of the scanning optical member relative to the fixing of the original, and the relative movement of a predetermined distance by the control means is defined as the movement of the original relative to the stopped scanning optical member. The scanning optical member moves with respect to the fixed document, the document image is read, and the document moves by an amount corresponding to the area of the document image that is not properly read due to the scanning optical member temporarily stopping during reading. By doing so, it is possible to read the area properly again.

If the relative movement at the time of reading is the movement of the original relative to the fixing of the scanning optical member, and the relative movement of a predetermined distance by the control means is the movement of the scanning optical member relative to the stopped original, The original is moved relative to the fixed scanning optical member, the original image is read, and the scanning optical member moves by an amount corresponding to the area of the original image that is not properly read because the original stopped temporarily during the reading. By doing so, it is possible to read the area properly again.

When the amount of image information read by the scanning optical member reaches an allowable amount, a stop signal for temporarily stopping the relative movement between the original image and the scanning optical member is sent to the control means, whereby the image information to be read is leaked. Never.

The predetermined distance for the relative movement of the scanning optical member in the opposite direction is a braking distance from when the scanning optical member starts to decelerate to when it stops, and a constant speed when the scanning optical member starts accelerating to start moving. By moving the approach distance required to reach the distance, the distance corresponding to the area that is not properly read is moved.
All image areas can be read properly in the shortest time.

The image information read after the scanning optical member starts accelerating to start moving and reaches a constant speed,
By storing the image information until immediately before the scanning optical member starts to decelerate in the storage means, only the properly read portion is stored, and by adjusting to the control of the control means, it is possible to faithfully reproduce the original image. Images can be stored.

The image information read after the scanning optical member starts to move and starts accelerating to reach a certain speed, and
By transmitting the image information until immediately before the scanning optical member starts decelerating, the transmitting unit transmits only the portion that has been properly read, and by following the control of the control unit, it is possible to faithfully reproduce the original image. Images can be sent.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a positional relationship between a scanning optical member (mirror base 8) and a document in an image reading apparatus according to a first embodiment of the present invention in order according to control.

FIG. 2 is a view for explaining the operation of each section inside the image reading apparatus under control of the image reading apparatus according to the first embodiment of the present invention;

FIG. 3 is a diagram schematically illustrating a positional relationship between a scanning optical member (mirror base 8) and a document in an image reading apparatus according to a second embodiment of the present invention in order under control.

FIG. 4 is a schematic cross-sectional configuration diagram of an image reading apparatus.

FIG. 5 is a view for explaining the positional relationship between a scanning optical member (mirror base 8) and a document and the operation of each section inside the apparatus under control according to the related art.

[Explanation of symbols]

1, 2 Automatic document feeder 8 Mirror base a1, a2, a3 Drive stop signal position of mirror base and C
CD reading stop signal position b1, b2, b3 Mirror base stop position and mirror base restart position c1, c2, c3 CCD reading restart position

Continued on the front page (72) Inventor Toru Shirakawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (8)

[Claims] A scanning optical member for moving the scanning optical member relative to a document image of a document having an image in a predetermined area to read the image, and moving the scanning optical member in a partial area of the predetermined area of the document image; And a control means for starting the movement again after being temporarily stopped, wherein the control means, when the relative movement between the original image and the scanning optical member is once stopped, the relative movement An image reading apparatus for relatively moving a predetermined distance in a direction opposite to the movement. 2. The method according to claim 1, wherein the relative movement at the time of reading is a movement of the scanning optical member with respect to the fixing of the document, and the relative movement by a predetermined distance by the control means is a movement of the document with respect to the stopped scanning optical member. The image reading device according to claim 1, wherein: 3. The method according to claim 1, wherein the relative movement at the time of reading is the movement of the original relative to the fixing of the scanning optical member, and the relative movement by a predetermined distance by the control means is the movement of the scanning optical member relative to the stopped original. The image reading device according to claim 1, wherein: 4. A stop signal for temporarily stopping the relative movement between the original image and the scanning optical member when the amount of image information read by the scanning optical member reaches an allowable amount. The image reading device according to claim 1, 2, or 3. 5. A predetermined distance in which the scanning optical member relatively moves in the opposite direction includes a braking distance from when the scanning optical member starts to decelerate to a stop, and a time when the scanning optical member starts accelerating to start moving. 5. The image reading apparatus according to claim 1, wherein the distance is a sum of a running distance required to reach a certain speed. 6. A storage device for storing image information read after the scanning optical member starts accelerating to start moving and at a constant speed and image information immediately before the scanning optical member starts decelerating. 6. The image reading apparatus according to claim 5, further comprising a unit. 7. A transmission for transmitting image information read after the scanning optical member starts accelerating to start moving and reaches a constant speed, and image information immediately before the scanning optical member starts deceleration. 6. The image reading apparatus according to claim 5, further comprising a unit. 8. An image forming apparatus comprising an image forming means for forming an image read by the image reading apparatus according to claim 1 on a sheet.