JPH06276366A - Original reader and shading correction system - Google Patents

Abstract

PURPOSE:To obtain the reader in which a carrier roller is saved by using an original separation roller to carry an original up to a read means and shading correction is executed based on an optimum white level reference and the original is read with high accuracy. CONSTITUTION:A carrier roller 8 is provided on a read means 10 or downstream thereof and an original position detection means 7 is provided upstream of the carrier roller 8. Furthermore, when a complete close contact type sensor is employed for the read means 10, a white reference section 9 is formed on the carrier roller 8 and entire shading correction is executed based on white reference levels by plural lines at a white reference correction means. Moreover, a carrier auxiliary means whose friction coefficient with respect to an original is set lower than that of an original separate means 4 is provided in contact with the paper feed roller 3 by pressing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading device in a facsimile, a scanner, a copying machine or the like.

[0002]

2. Description of the Related Art A conventional document reading apparatus provided with an automatic paper feeding means separates one of the stacked originals by a paper feeding roller and a document separating means abutting against the paper feeding roller, and feeds the separated originals. After the document is clamped by the document, the document front and rear ends are detected by the document position detecting means downstream of the conveying roller, and the document is conveyed at a predetermined speed by the conveying roller, and is read by the reading means provided further downstream on the document. It is configured to read images.

This is because the peripheral speed of the feed roller is set to the peripheral speed of the conveying roller in order to secure the speed for separating the original or to create a speed difference with the conveying roller to give tension to the original and remove wrinkles of the original. When the originals are not matched, and the originals separating means that separates the originals by abutting the paper feed roller apply the conveyance resistance to the originals that are stacked, the originals are separated by the paper feed roller and the originals separating means. As the document becomes weaker and slips occur, the rotation speed of the paper feed roller differs from the actual distance that the document is conveyed. This is to control the image reading area on the document by detecting the leading edge or the trailing edge of the document by the detecting means after the document is nipped by the conveying rollers with high accuracy.

As described above, since at least two rollers are required to reach the document reading means, the reading device needs a discharge roller for removing the document from the document reading means. Three rollers are needed.

Further, when the document reading means of the perfect contact optical system using the reading sensor having a shallow depth of field is used, a reading roller is required on the sensor, and the reading device must be composed of at least four rollers.

Further, when reading an original, it is necessary to correct the white reference value of the original reading means and to correct the secular change of the output of the original reading means and the temperature characteristic.

As related arts, there are those described in JP-A-57-93838, JP-A-64-64876 and JP-A-3-22751.

[0008]

In the above-mentioned prior art, there are many rollers constituting the document conveying system of the reading device, and at least 3 rollers are required.
In addition, the number of gears used for drive transmission is increased due to the need for four or more rollers, and the drive transmission efficiency is deteriorated and the motor torque as a drive source is required to be large, so that the device is downsized and low It was unfavorable to price. Further, since there are many rollers, there is a high possibility that a document is jammed in the middle of the conveyance path, and the reliability of the apparatus is insufficient.

Further, when the original document is conveyed to the original document reading means by removing the conveying roller and feeding the original document, the above-mentioned slippage of the original document occurs, but this is not taken into consideration. Further, in the case of a reading device using a reading sensor of a perfect contact optical system, the reading roller has a document feeding accuracy as a feeding roller, and it is necessary to also serve as a white reference value. (Transport roller)
The white reference correction is essential, but it is not considered.

[0010]

In order to reduce the number of rollers for conveying originals, a paper feed roller for separating the originals and an original provided on the reading means or on the further downstream side are conveyed with high accuracy. This can be achieved by a possible carrying roller and a document position detecting means provided on the upstream side of the carrying roller.

Further, in order to suppress slippage of the original by the paper feed roller, the auxiliary feeding means having a friction coefficient against the original lower than that of the original separating means is brought into contact with the paper feed roller to convey the original and the original. This can be achieved by providing it on the downstream side of the contact position of the means.

[0012]

In the document reading device, the leading edge of the document is detected by the document position detecting means and the reading is started according to the feeding amount from the reference position. However, since the feeding roller for controlling the document separation can feed the document to some extent, By detecting the leading edge of the document conveyed by the sheet feeding roller and considering the amount of document conveyance by the sheet feeding roller, it is possible to convey the document to the conveying roller provided on the reading unit or further downstream. Since the actual document reading is performed while the document is conveyed under the conveyance roller, the document is read with a predetermined high accuracy.

To suppress the slip of the original, the friction coefficient of the original is set to μ1, the friction coefficient between the original separating means and the original is set to μ2 (<μ1), and the pressing force of the original separating means to the paper feeding roller is set to F1. Then, the conveyance force F0 that acts on the downstream side of the document by these causes the friction force by the document separation means to be the conveyance resistance, and satisfies the condition of F0 = F1 (μ1−μ2)> 0. On the other hand, μ3 (<μ
When the conveyance assisting means having the friction coefficient 1) is brought into contact with the sheet feeding roller with the pressure force F3, the document conveyance force F4 is F.
4 = F0 + F3 (μ1-μ3)>F0> 0, and the carrying force increases.

The increase in conveyance force is due to the pressure force F of the document separating means.
Although it can be obtained by increasing 1, the ratio of the conveyance resistance force F1 × μ2, F3 × μ3 to the document conveyance force F0, F4 can be obtained by using the conveyance assisting means such that μ3 <μ2. This lowers the slippage, which can reduce slippage when the document is conveyed by the paper feed roller.

In addition, in a reading device using a perfect contact type reading sensor, when the carrying roller, which is the white reference portion, becomes dirty, the carrying roller is carried by a plurality of lines before reading the original, and it is obtained in each line. The maximum value (peak value) of the read information of the conveying roller, which is the white reference value, is obtained by the peak value correcting means, and the shading correction of the reading means is carried out by the shading correcting means based on this peak value, so that a wide range on the conveying roller is obtained. Since it is possible to read the non-contaminated portion of the white reference, it is possible to reduce the influence of the contamination.

[0016]

EXAMPLES The present invention will be described in detail with reference to examples.

FIG. 1 shows the configuration of a reading apparatus according to the first embodiment of the present invention, and FIG. 2 is a plan view.

In the figure, reference numeral 100 indicates the entire reader. Reference numeral 1 denotes a paper feed table, on which a plurality of documents 2 can be stacked. Reference numeral 1001 denotes a document guide, which is installed on the paper feed table 1 and configured to be movable left and right, and can position the document 2 in a restricted width direction. A sheet feeding roller 3 is rotatable with the sheet feeding shaft 301 (peripheral speed V3). The paper feed shaft is provided with a paper feed gear 17 for drive transmission and a one-way clutch 18. Reference numeral 4 denotes a document separating means, which in this embodiment is composed of a blocking member 401 which rotates about a rotating shaft 404 and a separation pushing spring 402. Reference numeral 6 denotes a document detecting means, which is provided in the vicinity of the downstream of the paper feed table 1 and can detect that the leading end of the document 2 has reached the paper feed roller 3. A conveyance path 5 guides the document 2. Reference numeral 7 denotes a document position detecting means using a mechanical switch, which can detect passage of the document 2 by being provided in the middle of the conveyance path 5. The document position detecting means 7 can be configured by a combination of a light emitting element and a light receiving element, and the amount of movement of the document required for switching detection / non-detection of the document 2 can be made smaller than the stroke of the mechanical switch. However, when a document that absorbs or transmits light is conveyed, the document cannot be detected and the practical range is limited.

Reference numeral 8 denotes a conveyance roller, which rotates at a peripheral speed higher than that of the paper feed roller 3 (peripheral speed V8, V8> V3), and a white reference portion 9 which gives a white reference value used for shading correction described later. It is configured to be used for both. Further, the conveying roller 8 is set such as the surface friction coefficient, the width, and the pressure-bonding force so that the conveying force of the original becomes higher than the conveying force of the original by the paper feed roller 3 and the original separating means 4. Reference numeral 10 denotes a reading unit, which uses a perfect contact type reading sensor having a shallow depth of field on the document side and outputs reading information 11. 12 is a paper discharge roller, which is provided in the discharge path 19. Further, the control controller 16 that controls the entire apparatus reads the read information 11 via the system bus 160.
Shading correction means 15, peak value correction means 25, paper feed roller 3, transport roller 8, paper discharge roller 1
The motor drive circuit 131 and the like driven by the drive motor 132 is controlled via the drive means 13 (not shown) composed of a gear or the like engaged with 2.

FIG. 3 shows the construction of the paper feed gear 17 and the one-way clutch 18 provided on the paper feed shaft 301 shown in FIG.

The paper feed gear 17 is rotatably attached to the paper feed shaft 301 and has an engagement hole 171. The one-way clutch 18 is fitted to a D-cut portion 302 provided at the tip of the paper feed shaft 301, and is rotatably attached to the holding plate 183 that rotates integrally with the paper feed shaft 301 and the paper feed shaft 301. Protrusions 184 that engage with the engagement holes 171
And a clutch spring 181 having a slightly small winding diameter is incorporated in the holder 182. The one end 185 of the clutch spring 181 is engaged with the push plate 183.

Further, the reading means 10 is a wiring board 106.
It has a light source 101 such as an LED array provided above, a transparent substrate 104 such as glass provided on the side of the transport roller 3, and a photoelectric conversion unit 102. When there is no carrier roller 8 and reading means 1
The reading position 105 on the roller surface in contact with 0 is read, and the reading information 11 as shown in FIG. 5 is output.

FIG. 6 shows the original reading area on the original 2, but the original reading area 201 is secured with the leading end unread area 202 and the trailing end unread area 203 by the reading device 100 having the above configuration. It is readable. The operation of this embodiment will be described below.

FIG. 7 is an operation flow chart of document feeding according to this embodiment. When the reading apparatus 100 is turned on and the initial state setting is completed, the process shifts from step n1 in the reading standby state to n2 which is the actual reading operation. When the document 2 is set on the paper feed tray 1, the document detecting means 6 changes to the ON state, and when the control controller 16 detects this, the process proceeds from step n2 to n3, and the control controller 16 drives the motor drive circuit. Drive motor 132 via 131
Drive at least the paper feed gear 17 and the transport gear 80.
The drive transmission means 14 (not shown) composed of a gear train or the like engaged with 2 rotates the paper feed roller 3 counterclockwise in FIG. 1 and rotates the transport gear 802 clockwise, step n4. Move to.

After the light source 101 emits light, the light source 101
After a predetermined period of time during which the temperature is stabilized, the white reference portion 9 which also serves as the conveyance roller 8 is read by the reading means 10 for a predetermined number of lines (L).
3) Read, read information 1 by the peak value correction means 25
The peak value of 1 is obtained, and the shading information 2541 in which only the peak value is combined with the read information 11 is used to determine the correction value by which the shading correction unit 15 corrects the sensitivity change of the photoelectric conversion unit 102 with time and the temperature change. Then, in the subsequent reading, the shading-corrected read information 11 'is output. In this step n4, the original 2 does not reach the reading means 10, and the transport roller 8 which also serves as the white reference portion 9 can be surely read and correct shading correction is possible. Further, by the operation described later, the peak value of the read information 11 read by the peak value correction means 25 can be set to a plurality of lines (L
3) Since the white reference portion 9 can be read in a wide range by driving, there is a high possibility that a portion with little stain can be read, and the white reference portion 9 is partially soiled to adjust the correction level according to the peak value of the read information 11. The effect is not affected by.

Further, the paper feed roller 3 and the transport roller 8
When the document is continuously driven, the document 2 stacked on the paper feed tray 1 is separated from the document at the bottom and is conveyed into the conveyance path 5.

The principle by which the original is separated is shown below. The original 2 stacked on the paper feed table 1 having a certain inclination in the original conveying direction is pinched at its leading end by the paper feed roller 3 and the original separating means 4 by its own weight and the original catching member 1002 not shown. To be done. Here, if the friction coefficient between the paper feed roller 3 and the original 2 is μ1, the friction coefficient between the original 2 and the blocking member 401 of the original separating means 4 is μ2, and the friction coefficient between the originals 2 is μ4, then μ1>μ2> μ4. 2 from the bottom
The first and second originals 2 are stopped by the blocking member 401, and only the lowermost original 2 is conveyed downstream by the conveying rollers 3.

When it is detected that the leading edge 2021 of the conveyed document 2 has passed through the document position detecting means 7 provided in the middle of the conveying path 5 and changed to the ON state (step n5), the ON state of the document detecting means is turned on. After driving the drive motor 132 by a predetermined number of lines (L4 ≧ 0) so as to ensure the state (step n6), the drive motor 132 is stopped (step n).
7) Stop feeding the original 2. Further, the completion of the paper feeding operation is displayed by a display means or a sound source (not shown) such as LED or liquid crystal, and the paper feeding operation is completed (step n8). In the case of a reading apparatus that automatically shifts from the paper feeding operation to the reading operation, even if there is no n8 paper feeding operation completion indication, the paper feeding operation is not hindered and effective.

In the paper feeding operation according to this embodiment, since the original 2 is stopped on the upstream side of the conveying roller 8, the resistance force is exerted when the operator pulls out the original 2 that has been fed from the direction of the paper feed tray 1. Only by sandwiching the paper feed roller 3 and the document separating means 4, a relatively small force is required and the document 2 can be prevented from being damaged.

FIG. 8 shows a peak value correcting means 25 according to the present invention.
FIG. 9 is a configuration diagram of an embodiment of the present invention, and a brief description has been given of the shading correction in step n4 of the paper feeding operation of FIG.

The peak value correcting means 25 is the reading means 10
From the memory means 251 such as a RAM (random access memory) which stores the read information 11 from the read information 11 and the stored read information 2511, and the peak values of the read information 11 and the stored read information 2511. A peak value detector 252 that outputs a peak value 2522 and a peak value 2521, and a peak value 2521, 2
A divider 253 for obtaining the ratio 2531 of 522 and a multiplier 254 for obtaining shading information 2541 by multiplying the memory read information 2511 and the ratio 2531. The operation will be described below.

In the reading apparatus 100 of the present embodiment, since the white reference portion 9 also serves as the carrying roller 8, it is considered that the carrying roller 8 becomes dirty and the output of the read information 11 becomes small as the apparatus is used. However, when the white reference portion 9 is not dirty when the reading device 100 is shipped, the white reference portion 9 or another white reference original 901 (not shown) is read, and the read information 11 read by the means 10 is stored and read. The information 2511 is stored in advance in the memory unit 251.

When shading correction in reading is performed, the peak value 25 of the stored read information 2511 is obtained.
21 and the peak value 2522 of the read information 11 read by the reading means 10 are obtained by the peak detector 252, this ratio 2531 is output by the divider 253, and the shading information 2541 is obtained as the product of the stored read information 2511 and the ratio 2531. To the controller 16 via the system bus 160, the controller 16 stores a predetermined number (L3) of line driving ratios 2531 for each line and multiplies the maximum ratio 2531. The data is output to 254 and shading correction is performed by the peak value of the read information 11 read in a wide range. By the above operation, the peak value correction based on the white reference is finished, and when the preparation for the shading correction is completed, the reading operation is started.

FIG. 9 shows the flow of the document reading operation according to this embodiment. Step s1 is the same as step n8 when the paper feeding operation in FIG. 7 is completed.

In this state, when the read command 23 is generated by a switch (not shown) of the reading device 100 or an external signal, the control controller 16 drives the drive motor 132 (step s2), and the paper feed roller 3, the transport roller 8 and The discharge roller 12 is rotated (step s3). A predetermined number of conveyance lines (L5) in which the leading edge unread area 202 of the document 2 passes the reading position 105 of the reading means 10.
At the time when the sheet is conveyed (step s4), reading of one line by the reading means 10 is started (step s5). The document position detecting means 7 is turned on by the control controller 16.
From the OFF state to the OFF state is detected (step s
6) If the ON state continues, the process returns to step s5 to continue reading one line. Document 2 currently being read
When the trailing edge 2031 passes, the document position detecting means 7 turns off.
Since the state changes to the F state, the process moves to the next step (step s7), and one line is read continuously. Further, it is judged whether or not the trailing edge unread area 203 of the original 2 has been carried by the predetermined number of carrying lines (L6) carried to the reading position 105 (step s8). Continue reading. When the conveyance line reaches L6, the output of the document detecting means 6 is detected (step s9), and if it is in the OFF state, the process proceeds to step s10 which is the document discharging operation, and the distance L2 of the trailing edge unread area 203 is set.
And the distance L7 from the reading position 105 to the discharge roller 12
The original 2 is conveyed by a distance L8 line which is equal to or more than the above, and the drive motor 132 is stopped (step s10) when the rear end 2031 of the original passes the conveying roller 12 (step s10).
11) Then, the document reading is completed (step s12). On the other hand, if the original detection unit 6 is still in the ON state in step s9, the next original 2 is present on the paper feed table 1, so the drive motor 132 continues to be in the driven state, and the 1 shown in FIG. Similar to step n5 of the feeding operation of the second original 2, the paper feeding roller 3, the conveying roller 8 and the discharging roller 12 are driven until the original position detecting means 7 changes to the ON state (step s13). Predetermined transport amount L in step n6
4 and the predetermined conveyance amount L5 obtained in step s4, the original 2 is conveyed by a predetermined conveyance amount L9 (step s1.
4) The procedure moves to step s5, and the second original 2 is read. By repeating steps 5, 6, 7, 8, 9, 13, and 14, the originals 2 stacked on the paper feed tray 1 are separated and read one by one from the bottom, and when the last one is finished, The transition from step s9 to step s10 described above occurs, and the reading operation is completed.

FIG. 10 is a schematic diagram at the time of shifting from step s8 to step s9 in the continuous read operation of the embodiment shown in FIG. The document position detecting means 7 is at the position 7a when there is no document 2, but is turned from the OFF state to the ON state when a part of the document is pushed by the leading edge 2021 of the document and is rotated to the position 7c by the distance L12. , And further rotate to 7b. Further, when the trailing edge 2031 of the document passes 7b, the distance L10 is returned and 7c is passed to shift from the ON state to the OFF state. Therefore, in order for the document position detecting means 7 to be ON / OFF between the continuously conveyed documents 2a and 2b so that the documents can be separated and detected, the document interval needs to be larger than L10, and L10 + L12. It is enough. However, even if the above conditions are satisfied, the document 2b to be read next is read.
The leading edge 2021 of the document is located at a distance L1
It is conceivable that it will be transported to a point past 1 and in this case there will be a problem in processing in time series with steps S7,8,9,13,14, but steps S13,14 will be replaced with steps S7,8,9. By performing parallel processing, the problem is resolved and effective.

Next, a means for providing a document interval will be described with reference to FIGS. 1, 3 and 4.

When the first original 2 is separately fed, the drive motor 132 is driven as described above, and the feed gear 17 is moved by the drive transmission means 14 (not shown) so that the feed roller 3 shown in FIG.
Rotate in the direction of rotation. This driving force is transmitted to the clutch spring 181 through the holder 182 by the engagement between the engagement hole 171 and the protrusion 184 (state of FIG. 4A). On the other hand, since the paper feed roller 3 is pressed by the document separating means 4 by the pressing force of the separation pressing spring 402, the paper feed shaft 301 and the pressing plate 183 assembled together with the paper feed roller 3 are integrated.
Applies a rotational load at the spring tip portion 185 engaging with the holding plate 183. The clutch spring 181 is twisted in the winding direction by the driving force and the rotational load, and the inner diameter becomes smaller, so that the holder 182 and the holding plate 183 are integrally connected, and the driving force of the sheet feeding gear 17 is increased by the one-way clutch. It is transmitted to the paper feed roller 3 via 18 to generate a conveying force for the document 2 and also rotate the paper feed roller 3 at the peripheral speed V3. Next, when the leading edge 2021 of the original is nipped by the conveying roller 8 driven with a large conveying force because the peripheral speed is faster and the friction coefficient is higher than that of the paper feeding roller 3, the original 2 moves around the conveying roller 8. The original 2 conveyed at a speed substantially equal to the speed V8 and pressed by the original separating means 4 is fed by the paper feed roller 3.
A peripheral speed higher than the peripheral speed given by the paper feed gear 17 (>
Rotate at V3). Therefore, the twisting direction of the clutch spring 181 is reversed and twisted in the reverse winding direction of the spring, so that the inner diameter is increased and the connecting force between the holder 182 and the holding plate 183 is weakened, resulting in the state shown in FIG. The amount 20 is generated between the engagement hole 171 and the protrusion 184, and thereafter, the clutch spring 181 only idles and the interval does not widen. The trailing edge 2031 of the first document is the feed roller 3
When the second original 2 is fed after passing through the sheet feeding roller 17, the driving force of the sheet feeding gear 17 causes the sheet feeding roller to move from the state shown in FIG. 4B to the state shown in FIG. 3 does not rotate, the document 2 is stopped, and paper feeding is resumed from the state shown in FIG. Therefore, the one-way clutch idling amount of 20 is provided between the documents. Further, since the first original 2 is conveyed by the conveying roller 8 and the second original 2 is conveyed by the paper feeding roller 3, an interval due to the difference in peripheral speed between both rollers is added, and the original interval is further expanded. A document interval is similarly provided for the second and subsequent sheets. Therefore, the one-way clutch idling amount 20 is set to ON / OFF of the document position detecting means 7 in FIG.
By setting the switching distance L10 to be larger than the switching distance L10, the document position detecting means 7 can operate between the document intervals between the trailing edge 2031 of the previously transported document and the leading edge 2021 of the next document to be transported. Each original 2 can be separately detected.

The one-way clutch idling amount 20 depends on the length of the document 2 to be fed first and the peripheral speed difference between the feeding roller 3 and the conveying roller 8. In other words, the one-way clutch idling amount 20 is generated only on the original document that is fed first, and is calculated only by subtracting the distance between the feed roller 3 and the transport roller 8 from the length of the original document. If the gap is insufficient or the peripheral speed difference is small, the next document is fed while the state shown in FIG. 4B is reached, and the desired document interval (L10
Since the following cases occur, the originals can be separated and detected by setting them according to the length of the originals that poses no practical problem.

With the above operation, in this embodiment, a plurality of originals can be automatically separated and correctly read by a simple roller structure.

FIG. 11 shows a block diagram of another embodiment of the peak value correcting means 25 according to the present invention, and FIG. 12 shows a read operation flow using this embodiment.

The ratio 253 which is the output from the divider 253
1 is input to the comparator 255, and the output 255 of the comparator 255
1 is input to the multiplier 254 and another memory means 256, the multiplier 254 outputs shading information 2541 to the output 2551 and the memory read information 2511, and the information 2561 in the memory means 256 is input to the comparator 255. Other configurations are the same as those of the embodiment shown in FIG. The operation will be described below.

When the white reference portion 9 is not dirty when the reading device 100 is shipped, the white reference portion 9 or another white reference original 901 (not shown) is read, and the read information 11 read by the means 10 is stored and read. Information 2511 is stored in the memory means 251 in advance, and when the first original 2 is fed, the peak value 2521 of the stored read information 2511 and the read information 11 read by the reading means 10 are stored.
Peak value 2522 of the
Until the divider 253 outputs this ratio 2531,
Is the same as the embodiment described above. In the case of the first original, the ratio 2531 passes through the comparator 255, but the value as it is is used as the comparison ratio 2551 in the multiplier 254 and the memory means 256.
The memory means 256 stores the comparison ratio 2551 as a storage ratio 2561. Further multiplier 254
Outputs the product of the memory read information 2511 and the comparison ratio 2551 as the shading information 2541 to the shading means 15. In the shading correction performed before reading the second original 2 in step s142, the ratio 253 based on the read information 11 of the newly acquired white reference portion 9 is 253.
1 and the already-stored storage ratio 2561 are compared by the comparator 2
55, the higher ratio is output to the multiplier 254 and the memory means 254 as a new comparison ratio, and the memory means 256 stores it as a storage ratio 2561. Further, the multiplier 254 outputs the product of the memory read information 2511 and the comparison ratio 2551 as the shading information 2541 to the shading means 15. The shading correction with the peak value correction between the originals can be performed by repeating the same operation for the third and subsequent sheets. This method is shown in Figure 1.
Even in the reading apparatus 100 of the close contact reading type in which the white reference portion 9 may be soiled as in the first embodiment, the shading correction can be correctly performed without being affected by the contamination of the white reference portion 9. Further, as in the reading means 10 shown in FIG. 1, the light source 101 and the photoelectric conversion B 102 are provided adjacent to each other, and particularly, in the case where the temperature characteristic of the photoelectric conversion unit 102 is such that the output rises as the temperature rises, This has the effect of compensating for the temperature change. Further, according to the present embodiment, it is not necessary to output the ratio 2531 from the peak value correction means 25 shown in FIG. 1 to the system bus 160, and it is effective even without it.
However, in the use of the apparatus 100, the controller 16 determines the change over time in the ratio 2531, and, for example, when the ratio has changed drastically than in the previous use, an operation such as issuing a warning to the user is added. Therefore, it is also effective to improve the usability of the device.

Details of the read operation will be described with reference to FIG.
In the illustrated read operation, steps s1 to s4 and steps s10 to s12 in the flow shown in FIG. 9 are common and are omitted in this figure. The present shading correction method is effective when reading a plurality of originals 2 and is the same as in FIG. 8 when there is only one original 2, so the continuous reading operation will be described below.

Steps s5 to s13 are the same as those of the embodiment shown in FIG.
Shading correction step s14
2 (L3) is added, and a predetermined number of lines are conveyed before and after that L13
(Step s141) and transport L14 for a predetermined number of lines
(Step s143) is provided (L3 + L13 + L14 = L9). That is, step s8
When the original 2 is conveyed by the distance L9 at the end, the original 2 is conveyed downstream of the leading end unread area 202 (L1) to the reading means, but from the end of step s8, the trailing end unread area 203 (L2, L9-L1> The original 2 is not present on the reading means 10 at the time when the sheet is conveyed more than L2). Also,
The leading edge 2021 of the next original 2b reaches the reading means 10 after L9-L1 is conveyed from the end of step s13. Therefore, by selecting the line number L13 such that L2 <L13 <L9-L1-L3, the step is performed. In the shading correction in s142, the reading unit 10 sets the white reference portion 9
Can be read.

FIG. 13 is a plan view of the reading apparatus 100 according to the present invention which uses the peak value correcting means 25 shown in FIG. 8, and shows when the originals 2a and 2b are skewed and at the end of step s8 in FIG. It is a thing. Since the document 2 is regulated in the width direction by the document guide 1001, when the document guide 1001 is set to be larger than the width of the document 2, the document 2 is conveyed while being inclined with respect to the conveyance direction as shown in the figure. A line phenomenon may occur. Since the reading apparatus 100 of this embodiment has only one document position detecting means 7, when the detection state of the document position detecting means 7 changes from OFF to ON as the leading edge 2021 of the document 2b passes, The front end of the document 2b on the front side of the skew is already downstream by the distance L201 due to the skew, and the front end on the rear side of the skew is upstream by the distance L101. Also the previous manuscript 2
When a similar skew occurs in a, the trailing end on the skew front side is a distance L2 from the reading position 105 at the end of reading.
01 downstream, and the rear end of the oblique rear side is a distance L101.
Only upstream. Therefore, when the shading correction between the originals shown in FIG.
Shading correction was carried out after carrying a predetermined number of lines of 13 and peak value correction was added by the read information 11 of the white reference portion 9.
Since there is a possibility that a part of the original 2 is sandwiched between the reading means 10 and L2 + L201 <L13 <L9-L1-
The problem is solved and effective by setting the number of transport lines L13, which is L3-L101. The distances L101 and L201 to be newly considered are set in consideration of the case where the document 2 is skewed by several mm, so that there is no practical problem.

FIG. 14 shows another read operation flow according to the embodiment of the peak value correcting means 25 shown in FIG. In step s143 of the flow of the reading operation shown in FIG. 12, the reading means 10 reads the inside of the trailing edge unread area 203 of the original 2a, and step S1432 (L3) is performed to perform peak value correction in shading correction. In addition, a predetermined number of lines L15 and a predetermined number of lines L16 are added before and after the addition.
It is characterized in that (L15 + L16 + L3 = L14) is provided. That is, from the end of step s8, the original 2 is present on the reading means 10 at the time when the conveying amount equal to or smaller than the trailing edge unread area 203 (L2, L15 <L2) is conveyed, and the original 2 after the reading is conveyed by the conveying roller 8. Since it is driven by, there is almost no slippage in conveyance, and the original 2 can be read reliably.

The operation will be described below.

When the white reference portion 9 is not dirty when the reading device 100 is shipped, the white reference portion 9 or another white reference original 901 (not shown) is read, and the read information 11 read by the means 10 is stored and read. Information 2511 is stored in the memory means 251 in advance, and when the first original 2 is fed, the peak value 2521 of the stored read information 2511 and the read information 11 read by the reading means 10 are stored.
Peak value 2522 of the
Until the divider 253 outputs this ratio 2531,
This is the same as the embodiment of the first embodiment, including the storage of the storage ratio 2561 for the first original, the output of the shading information 2541 to the shading unit 15, and the shading correction performed before the second original 2 is read in step s142. The operation is similar to that of the embodiment shown in FIGS.

In the shading correction for reading the first original 2a in step s1432, a new ratio 2531 based on the read information 11 in the rear end unread area 203 of the newly acquired original 2a and a stored ratio 25 already stored.
61 is compared by the comparator 255, and the higher ratio is used as a new comparison ratio, and the multiplier 254 and the memory means 25 are used.
4 and the memory means 256 stores it as a storage ratio 2561. Further, the multiplier 254 stores the memory read information 2
The product of 511 and the comparison ratio 2551 is output to the shading means 15 as shading information 2541. Three
The shading correction with the peak value correction between the originals and the rear end of the originals can be performed by repeating the same operation for the first and subsequent sheets. In this method, even in the reading device 100 of the contact reading type as shown in FIG. 1 in which the white reference portion 9 may be soiled, the shading correction can be correctly performed without being affected by the contamination of the white reference portion 9. 11 and 12
In addition to the same effect as the embodiment of the above, the white reference portion 9
For users who use documents with higher whiteness than
There is also an effect that the white reference can be corrected. In addition, it is necessary to read a part of the original in order to add the original to the peak value correction, and there is an advantage that the above-described skew feeding phenomenon of the original is not adversely affected.

FIG. 15 is a block diagram of a reading apparatus according to another embodiment of the present invention. The embodiment shown in FIG. 1 is characterized in that the transport roller 12 is deleted and the paper discharge path 19 is arranged downward with respect to the document transport direction.

The original 2 conveyed into the paper discharge path 19 is naturally dropped by its own weight, so that the original 2 after the reading is completed.
Is discharged to the outside of the reading device 100, it is effective to set the predetermined number of conveyances in step s10 of the reading operation flow shown in FIG.
The other operations such as the one-way clutch 18, the peak value correcting means 25, and the feeding and reading are the same, and the same effects are obtained. Further, according to the present embodiment, since the paper discharge roller 12 is deleted, there is an effect that the reading device 100 can be further reduced in cost and downsized.

FIG. 16 is a block diagram of a reader according to another embodiment of the present invention. In the reading apparatus 100 according to the embodiment of the present invention shown in FIG. 1, conveyance by a leaf spring, a pinch roller, or the like that comes into contact with the sheet feeding roller 3 at the downstream side of the contact point between the sheet feeding roller 3 and the document separating means 4. The feature is that the auxiliary means 21 is provided. The conveyance assisting means 21 is formed on the document separating means 4, and the separation pushing spring 402 presses the document separating means 4 against the conveying roller 3 as the document separating means 4 is pressed against the conveying roller 3. In order to separate and feed the original 2, the friction coefficient between the paper feed roller 3 and the original 2 is μ1, the friction coefficient between the original 2 and the blocking member 401 of the original separating unit 4 is μ2, and the friction between the originals 2 is As described above, if the coefficient is μ4, the relationship of μ1>μ2> μ4 is required. However, by setting the friction coefficient μ3 between the conveyance assisting means 21 and the document 2 to μ3 <μ2, the document 2 can be conveyed by a large amount. Can give power. Friction coefficient μ
In order to keep 3 lower than μ1, the conveyance assisting means 2
1 is made of a material having a low friction coefficient, or the contact width with the paper feed roller 3 is made smaller than the contact width of the document separating means 4, which is effective. Also, manuscript 2
Since the principle of reducing the slippage of the conveyance is described in the section of "Operation", it is omitted here.

In the reading device 100 of this embodiment, the one-way clutch 18, the peak value correcting means 25 and the paper feed,
The operations such as reading are all the same and have the same effect. Further, in the present embodiment, there is an effect of reducing the slip of the original document 2 which is fed by the feeding roller 3 and is fed, and the reading area 201 can be secured with high accuracy.
4 has an advantage that the shading correction operation between originals can be accurately performed.

FIG. 17 is a block diagram of an embodiment of the conveyance assisting means 4 of the embodiment shown in FIG. It is characterized in that conveyance assisting means 21 and 21 'such as leaf springs are provided on both left and right sides of the blocking member 401 of the document separating means 4 as a center.
In this embodiment, the conveyance assisting means 21 and 21 'hold the document 2 at two points in the width direction, so that there is an effect that skewing of the document 2 which occurs between the paper feed roller 3 and the document separating means 4 can be suppressed. . Further, by providing the transport assisting means 21 and 21 'with different spring coefficients, the effect of adjusting the balance of the transport force on the document 2 and positively suppressing the skew of the document 2 is effective. .

FIG. 18 is a block diagram of another embodiment of the conveyance assisting means 4 of the embodiment shown in FIG. Document separating means 4
The blocking member 401 is divided into left and right parts, and the conveyance assisting means 21 is provided at a position abutting on the widthwise center of the sheet feeding roller 3 between them. The present embodiment has the same effect of suppressing slippage in the conveyance of the document 2, and since it abuts on the center of the paper feed roller 3, the conveyance force applied to the document 2 is not unevenly distributed on the left and right sides. It is effective because it has the advantage that it does not cause it.

FIG. 19 is a block diagram of a conveyance assisting means 21 using another document separating means 4 of the reading device 100 according to the present invention. In the reading device 100 of the embodiment shown in FIG. 16, the document separating means 4 is in contact with the conveying roller 3 to sandwich the document 2 and is constituted by a reversing roller 403 which rotates in a direction opposite to the rotation of the paper feeding roller 3. It is characterized by having done. The document separating means 4 using the reversing roller 403 is a well-known technique, but in this case as well, the conveyance assisting means 21 of the present invention is effective since it has the effect of reducing slippage during conveyance of the document 2.

FIG. 20 is a block diagram of an embodiment in which another conveyance assisting means 21 is provided in the reading device 100 according to the present invention. In one embodiment of the reading apparatus 100 shown in FIG. 16, the sheet feeding roller 3 and the document separating means 4 are fixed on the chassis 501 holding the sheet feeding path 5 ′ or the sheet feeding path 5 ′ (not shown). The conveyance assisting means 21 is provided so as to contact the sheet feeding roller 3 on the downstream side of the contact point. FIG. 17 with respect to the blocking member 401,
This can be realized by setting the position as in the embodiment shown in FIG. In the reading device 100 of the present embodiment, the operations such as the one-way clutch 18, the peak value correcting means 25 and the feeding and reading are the same as those of the embodiment of FIG. Further, in this embodiment, the transport assisting means 21
Since the pressure force applied to the paper feed roller 3 can be set independently of the pressure force applied to the paper feed roller 3 by the document separating means 4, there is an advantage that the magnitude of the pressure force is not limited.

FIG. 21 shows a reading device 100 according to the present invention.
FIG. 6 is a configuration diagram of another embodiment of FIG. In the embodiment shown in FIG. 1, the document delay detecting means 70 is arranged at a position distant from the document position detecting means 7 by a predetermined distance L70 in the document conveying direction.
1 is arranged, and a document delay amount correction unit 23 configured by a mechanical switch or the like, the output state of which is changed depending on the presence or absence of the document 2, is provided. The operation will be described below according to the operation flow shown in FIG. The document delay amount detection means 701 and the document delay amount correction unit 23 of this embodiment are
When the original 2 is fed and the original position detecting means 7 is turned off,
The operation is started slightly before the change to the N state, and other operations are similar to those of the embodiment shown in FIG.

The start is step n3 in the paper feeding operation shown in FIG. 7 or step s in the reading operation shown in FIG.
It is 9. Next, the paper feed roller 3 and the conveyance roller 8 are driven to convey the original by one line (step s131), and it is determined whether the original delay detection means 701 is in the ON state (step s132). If it is in the OFF state, the document 2 has not reached the document delay detecting means 701.
It returns to 1 and repeats until it becomes an ON state. When it is changed to the ON state, the line counter 71 (not shown) is reset (step s133), and every time the original is conveyed by one line (step s134), 1 is added to the count value 711 of the line counter 71 (step s135).
Next, it is judged whether the document position detecting means 7 is in the ON state (step s136).
Returning to step 134, this is repeated until the document position detecting means 7 is turned on. When the document position detecting means 7 changes to the ON state, the process proceeds to step s137, and the correction coefficient e is calculated based on the ratio between the counter value 711 of the line counter 71 and the distance L70 between the document delay detecting means 701 and the document position detecting means 7. Obtained (step s137). Next, the product of the correction coefficient e is set to the carry amount L9 from the document position detecting means 7 until the reading of the document 2 is started as a new carry amount L9 '(step s138), and the document is carried thereafter.

According to this embodiment, the control controller 1
Since the control controller 16 can determine the delay amount (slip) of the actual transport amount of the original document 2 with respect to the transport amount of the original document 2 set by 6, using the correction coefficient e, the original document 2 in which the slip is always constant. Correct the transport delay of 2,
There is an effect that an accurate conveyance amount is given to the document and the document reading area 201 can be secured with high accuracy.

In the reading device 100 of the present embodiment, the operations such as the one-way clutch 18, the peak value correcting means 25 and other paper feeding and reading are the same as those in the embodiment of FIG. There is an additional effect that the amount of conveyance due to slippage can be corrected to ensure reliable operation. Further, the same effect can be obtained by applying it to another reading means 100 shown in FIGS. Further, even if the positional relationship between the document position detecting means 7 and the document delay detecting means 701 is reversed, the same operation is possible and effective.

Needless to say, the same effect can be obtained by using the document detecting means 6 as a substitute for the document delay detecting means 701 in the reading apparatus 100 of the embodiment shown in FIGS. 1, 15, 16 and 20. It is effective.

FIG. 23 shows a block diagram of another embodiment of the reading device according to the present invention. In the figure, 100 indicates the entire reader. Reference numeral 1 denotes a paper feed table, on which a plurality of documents 2 can be stacked. Reference numeral 1001 denotes a document guide, which is installed on the paper feed table 1 and configured to be movable left and right. The document 2 can be regulated and positioned in the width direction. A sheet feeding roller 3 is rotatable integrally with the sheet feeding shaft 301. The paper feed shaft is provided with a paper feed gear 17 for drive transmission and a one-way clutch 18. Reference numeral 4 denotes a document separating means, which in this embodiment is composed of a blocking member 401 which rotates about a rotating shaft 404 and a separation pushing spring 402. Reference numeral 6 denotes a document detecting means, which is provided in the vicinity of the downstream of the paper feed table 1 and can detect that the leading end of the document 2 has reached the paper feed roller 3. A conveyance path 5 guides the document 2. Reference numeral 7 denotes a document position detecting means using a mechanical switch, which can detect passage of the document 2 by being provided in the middle of the conveyance path 5. Reference numeral 8 is a conveyance roller, and 9 is a white reference portion that gives a white reference value.
Reference numeral 10 is a reading means, which includes a light source 101 and a photoelectric conversion unit 10.
2, and an optical member 10 formed by a combination of a lens and a mirror
The reading information 11 is output by using a reduction optical type reading sensor having a deep depth of field on the side of the document, which is configured by 3. Reference numeral 12 denotes a paper discharge roller, which is provided in the discharge path 12. Further, the control controller 16 for controlling the entire apparatus is constituted by a shading semi-correction means 15 for correcting the read information 11, a gear engaged with the paper feed roller 3, and the transport roller 8 via the system bus 160. A motor drive circuit 131 driven by a drive motor 132 is controlled via a drive unit 13 (not shown).

The reader 100 of the present embodiment is effective because it has the same effects as the operation of the embodiment shown in FIG.

Further, in the embodiment shown in FIG. 23, by using the reading means of the reduction optical system, the white reference portion 9 facing the reading means 10 can be fixed apart from the reading means 10. Therefore, since the white reference portion 9 is extremely less contaminated, even the reading device 100 having the configuration in which the peak value correcting means 25 is removed can perform an effective operation. In this case, although the operations in feeding and reading are different, the feeding and reading operations are possible according to the operation flows shown in FIGS. 7 and 9. Description will be given below with reference to the drawings.

In FIG. 7, when the power of the reading apparatus 100 is turned on and the initial state setting is completed, the process goes to the reading standby state from step n1 to n2. Next, the original 2 is set on the paper feed table 1, the original detecting means 6 is changed to the ON state, and the controller 16 detects this, and the process moves from step n2 to n3, and the controller 16 drives the motor. The drive transmission means 14 is configured to drive the drive motor 132 through the circuit 131 and at least include a gear train engaged with the paper feed gear 17 and the transport gear 802.
The paper feed roller 3 is rotated counterclockwise in FIG. 23 (not shown) and the transport gear 802 is rotated clockwise, and the process proceeds to step n4.

A predetermined time after the light source 101 emits light, the reading means 10 reads the white reference portion 9 for a predetermined number of lines (L3), and the obtained read information 11 is output uniformly. The shading correction is performed by the shading correction means 15, and a correction value for correcting variations in the sensitivity of the photoelectric conversion unit 102 due to the reading position, changes over time, changes due to temperature, etc. is determined, and the shading-corrected reading information 11 ′ is read in the subsequent reading. Output. In this step n4, the original 2 does not reach the reading means 10, and the white reference portion 9 can always be reliably read, and correct shading correction is possible. Further, if the paper feed roller 3 and the transport roller 8 are continuously driven, the document 2 stacked on the paper feed table 1 is separated from the document at the lowermost part and is transported into the transport path 5. When it is detected that the leading edge 2021 of the conveyed document 2 has passed through the document position detecting means 7 provided in the middle of the conveying path 5 and changed to the ON state (step n5), the ON state of the document detecting means is surely confirmed. Drive motor 132 to a predetermined number of lines (L
4 ≧ 0) After driving (step n6), drive motor 1
32 is stopped (step n7), and the conveyance of the original 2 is stopped. Further, the completion of the paper feeding operation is displayed by a display means or a sound source (not shown) such as LED or liquid crystal, and the paper feeding operation is completed (step n8). N in the case of a reading device that automatically shifts from the paper feeding operation to the reading operation (described later)
It is not necessary to indicate the completion of the sheet feeding operation of 8, and it is effective even if it is not displayed. Further, in the paper feeding operation according to the present embodiment, since the original 2 is stopped on the upstream side of the transport roller 8, the resistance force is applied when the operator pulls out the original 2 fed from the direction of the paper feed tray 1. Only by sandwiching the paper roller 3 and the document separating means 4, a relatively small force is required, and there is an advantage that the document 2 can be prevented from being damaged.

The reading operation is the same as the operation flow shown in FIG. 9, and the detailed description thereof will be omitted, but the same effect can be obtained. Further, it is needless to say that the same effect can be added by the same operation even if each unit for suppressing the slippage of the conveyance of the document 2 shown in FIGS. 16 to 22 is added to the reading apparatus 100 of the present embodiment. Is.

In the reading apparatus 100 of the present embodiment, since the depth of field of the reading means 10 is deep, the white reference portion 9 is set to the conveying path 5 '.
By providing it above, the reading means 10 or the document 2 and the white reference portion 9 can be separated from each other.
The white reference portion 9 is unlikely to be soiled even when used for a long period of time of 00, and there is an effect that shading correction can always be made constant. Further, by arranging the conveying roller 8 on the downstream side of the reading means 10, the conveying roller 8 can also have a function of discharging the document 2 after the reading is completed to the outside of the reading device 100, and therefore, a roller for conveying the document is supplied. Since it can be composed of two rollers, the paper roller 3 and the conveying roller 8, there is an advantage that the reading device 100 can be downsized and the cost can be reduced.

FIG. 24 is a block diagram of another embodiment of the reader 100 according to the present invention, and FIG. 25 is a plan view. The reading apparatus 100 of the present embodiment is characterized in that the one original detection means 7 is provided on the downstream side of the reading means 10 in the embodiment shown in FIG. 23, and has a conveyance assisting means 4. The operation is similar to that of the embodiment shown in FIG. 23 and has the same effect. Further, the conveying roller 8 is divided and the original document detecting means 7 is provided close to the conveying roller 8, so that the original document 2 detected by the original document position detecting means 7 is conveyed to be sandwiched by the conveying roller 8. Since the distance to be moved can be shortened, there is an effect that the slip amount of the document 2 conveyed in this section can be set small.

FIG. 26 is a block diagram of an embodiment in which the reader 100 according to the present invention described above is applied to a facsimile machine. The control controller 16 inputs / outputs control signals via the system bus 160, executes control of the entire system, and executes transmission operation, reception operation, copy operation, and the like. The reading device 100 uses the system bus 160 to read the read information 11 ′ that has been subjected to shading correction.
Is connected to a binarizing means 901 for binarizing. The encoding means 902 is a means for compressing the information amount of a binarized signal, and an encoding method such as MH or MR is known. The code memory 903 is a means for accumulating the coded read information, and is realized by a semiconductor memory. The communication means 907 is a means for transmitting and receiving a code on a communication line, and a modem is used in the case of a telephone line. The decoding means 904 is means for restoring the code from the code memory 903 via the system bus into binary image information. The recording unit 905 is a unit that prints a binary image signal on the recording paper 906, and a thermal printer using a thermal head is used, for example.
Even in the case of this embodiment, the image reading operation on the original 2 during copying and transmission is the same as that of the above-mentioned embodiment, and it is effective and effective.

[0073]

According to the present invention, since the document conveying system can be minimized, it can be constituted by at least two rollers, that is, a minimum separating roller and a conveying roller. As a result, the document reading device having the automatic paper feeding function can be made to have a very simple structure, and the number of gear trains in the drive transmission system can be reduced, which is a drive source force by preventing the reduction of drive transmission efficiency. Since the required driving force of the motor can be suppressed, the size and cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a reading device showing a first embodiment according to the present invention.

2 is a plan view of the first embodiment shown in FIG. 1. FIG.

FIG. 3 is a configuration diagram of an embodiment of a one-way clutch of a reading device according to the present invention.

4 is a cross-sectional view taken along the line AA of the one-way clutch shown in FIG.

FIG. 5 is a schematic diagram of the output of the reading means of the reading device according to the present invention.

FIG. 6 is a schematic view of a reading area of a document of a reading device according to the present invention.

FIG. 7 is a flowchart showing a document feeding operation of the reading device according to the present invention.

FIG. 8 is a block diagram of an embodiment of a peak value correcting means of the reading device according to the present invention.

FIG. 9 is a flowchart showing a document reading operation of the reading device according to the present invention.

FIG. 10 is a schematic explanatory diagram of a document conveyance amount when a document is continuously read by the reading device according to the present invention.

FIG. 11 is a configuration diagram of another embodiment of the peak value correcting means of the reading device according to the present invention.

12 is a flowchart showing a part of a reading operation of a reading device using the peak value correcting means shown in FIG.

FIG. 13 is a schematic explanatory view showing a state of a document when the document is skewed during continuous document reading in the reading device according to the present invention.

FIG. 14 is a flowchart showing a part of another reading operation of the reading device using the peak value correcting means shown in FIG.

FIG. 15 is a block diagram of a reading device showing a second embodiment according to the present invention.

FIG. 16 is a block diagram of a reading device showing a third embodiment according to the present invention.

17 is a configuration diagram of an embodiment of a conveyance assisting unit and a document separating unit of the reading device shown in FIG.

18 is a configuration diagram of another embodiment of the conveyance assisting means and the document separating means of the reading device shown in FIG.

19 is a configuration diagram of another embodiment of the conveyance assisting means and the document separating means of the reading device shown in FIG.

FIG. 20 is a block diagram of a reading device showing a fourth embodiment according to the present invention.

FIG. 21 is a plan view showing the configuration of a reading device showing a fifth embodiment according to the present invention.

FIG. 22 is an operation flow chart of the fifth embodiment shown in FIG. 21.

FIG. 23 is a block diagram of a reading device showing a sixth embodiment according to the present invention.

FIG. 24 is a block diagram of a reading device showing a seventh embodiment according to the present invention.

25 is a plan view of the seventh embodiment shown in FIG. 24. FIG.

FIG. 26 is a diagram showing an embodiment in which the reading device according to the present invention is applied to a facsimile device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Paper feed table, 2 ... Original, 3 ... Paper feed roller, 4 ... Original separating means, 5 ... Conveying path, 7 ... Original position detecting means, 8 ... Conveying roller, 9 ... White reference part, 10 ... Reading means, 11 ... Read information, 15 ... Shading correction means, 18 ... One-way clutch, 21 ... Conveyance assisting means, 23 ... Original document delay amount correcting section, 25 ... Peak value correcting means, 100 ... Reading device, 132 ... Drive motor, 160 ... System bus, 401 ... Blocking member, 403 ... Reverse rotation roller.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichi Narii 1410 Inada, Katsuta City, Ibaraki Hitachi, Ltd. Information & Video Media Division (72) Inventor Hiroshi Minota 1410 Inada, Katsuta, Ibaraki Hitachi, Ltd. Seisakusho Information & Video Media Division (72) Inventor Shinichi Shinoda 4026 Kuji Town, Hitachi City, Ibaraki Prefecture Hitachi Works Hitachi Research Laboratory (72) Inventor Kazuyasu Sato 502, Kintachi Town, Tsuchiura City, Ibaraki Hitachi Machinery Co., Ltd. In the laboratory

Claims (9)

[Claims] 1. A means for automatic sheet feeding, which separates the stacked originals one by one by a paper feeding roller and a document separating means in contact with the paper feeding roller and guides them to a document conveying path, and the original conveying path. At least a carrying roller for carrying the document fed by the paper feeding roller is provided therein, and by rotating the carrying roller, the image on the document is read by the reading means in synchronization with the carrying of the document. In a document reading device for obtaining read information, a white reference portion facing the reading means and a shading correction means of the reading means are provided, and a document position detecting means is provided on an upstream side of a document feeding path of the feeding roller to feed the paper. A one-way clutch is provided in the roller driving means, the peripheral speed of the conveying roller is set to be higher than the peripheral speed of the paper feeding roller, and the original document conveying force by the conveying roller is set between the paper feeding roller and the original roller. It is set to be larger than the document conveying force by the separating means, and shading correction is performed on the read information obtained by reading the white reference portion by the reading means before the reading of at least the first document. Original reading device. 2. The document reading apparatus according to claim 1, wherein a conveyance assisting unit is provided in contact with the sheet feeding roller at a position downstream of a contact position between the document separating unit and the sheet feeding roller in a document conveying direction. At the same time, the original reading device is characterized in that the coefficient of friction on the surface side of the conveyance assisting means which comes into contact with the original is lower than the coefficient of friction on the side of the original separating means which comes into contact with the original. 3. The document reading apparatus according to claim 1, wherein the feeding roller is installed in contact with the reading means, and the white reference portion is provided on the feeding roller. 4. The document reading apparatus according to claim 1, wherein shading correction of the read information is performed using a white peak value of the white reference portion and the read information of the original obtained by the peak value correcting means as a white reference value. A characteristic shading correction method. 5. The document reading apparatus according to claim 3, wherein the conveying roller is rotated before the reading of the document is started, the read information of a plurality of lines is obtained from the white reference portion, and the plurality of lines are read by the peak value correcting means. A shading correction method characterized in that the maximum value of minute reading information is obtained and used as a white reference value for shading correction. 6. The white reference correcting means of the document reading device according to claim 1, when a plurality of documents are continuously read,
A shading correction method characterized in that when reading the second and subsequent originals, the peak value of the read information of the original that has already been read is also taken into consideration when selecting the white reference value to perform shading correction. 7. The document reading apparatus according to claim 1, wherein a document delay detecting unit is provided at a predetermined interval in the document conveying direction of the document position detecting unit, and the document delay amount detecting unit detects the predetermined interval and the document. An original reading device characterized in that the original conveyance amount until the start of reading an original is determined by the ratio of the detection interval from the detection means to the original delay detection means. 8. The paper feed control method according to claim 1, wherein the original is stopped on the upstream side of the conveying path of the conveying roller when the first original is read. 9. The document reading device according to claim 1, wherein the conveying roller is installed on the downstream side of the document conveying path of the image reading means.