JP2001127966A - Image reading device, and method and storage medium thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading device which can obtain a clean read image that will not cause errors of a read line, when it restarts from a temporary stop page. SOLUTION: A motor is driven to start the feeding of an original (S5). When the tip of the original is detected (S6), a timer T is started to estimate a later position of the original (S7). When a temporary stop request is received, a number M of overrunning lines is decided via a control table 111 as the table value, corresponding to the original feeding velocity V and the time of the timer T (S14). When a restart request is received, an image read operation is carried out, so as not to fetch the image data equivalent to M lines according to the data (having overrun corresponding to M lines) which are read out of the table 111 (S16).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sheet-fed image scanner, an ADF, a facsimile apparatus,
The present invention relates to an image reading device, a method, and a storage medium applied to a multifunction printer or the like.

[0002]

2. Description of the Related Art Conventionally, in an image reading apparatus, the speed of transporting a document when re-reading from a temporary stop is the same as the speed of transporting a normal document. FIG. 9 is a timing chart showing a change in the position of a document, a document conveying speed, and a document pulling force with time in a conventional image reading apparatus.

In FIG. 1A, a horizontal axis 1006 indicates time, and a vertical axis 1001 indicates a position in the transport direction. 101
0 indicates a paper feed roller position. 1009 is a transport roller (1
(st transport roller) position. 1008 indicates an image reading position of the image sensor. 1007 indicates a position of a paper discharge roller (2nd transport roller).

[0004] Reference numeral 1002 denotes the leading end position of the original of the first page. Reference numeral 1003 denotes a rear end position of the original of the first page. 100
Reference numeral 4 denotes the leading edge position of the document on the second page. Reference numeral 1005 denotes a rear end position of the document of the second page.

[0005] In FIG. 1B, the vertical axis 1011 indicates the document conveying speed at the reading position, and the horizontal axis indicates time. In FIG. 10C, the vertical axis 1012 indicates the pulling force of the document at the reading position, and the horizontal axis indicates time.

First, until the leading edge of the original on the first page reaches the discharge roller position 1007 from the reading position, the original conveying speed is as shown in FIG.
As shown in FIG. Then, after the leading edge of the document enters the discharge roller position 1007, the trailing edge of the document moves to the transport roller position 107.
Until 09, the document conveying speed is as shown in FIG. 7B and the document pulling force is as shown in FIG. Similarly, from the time the trailing edge of the document passes through the transport roller position 1009 to the time the document passes through the reading position 1008, the document transport speed is as shown in FIG. 3C, and the document pulling force is as shown in FIG.

As described above, it can be seen that the document conveying speed and the document pulling force are different depending on the position of the document. This is because, by slightly changing the diameter of the roller, the original is conveyed with a slight tension so that the original is not bent at the image reading position.

FIG. 10 is a timing chart showing a change over time in the position of the original, the original conveying speed, and the original pulling force in another conventional image reading apparatus. In FIG. 9A, the horizontal axis 1102 indicates time, and the vertical axis 1101 indicates the position of the document. Reference numeral 1110 indicates the position of the sheet feeding roller. 1
Reference numeral 109 denotes a position of a transport roller (first transport roller).
Reference numeral 1108 denotes an image reading position of the image sensor.
Reference numeral 1107 denotes a position of a paper discharge roller (2nd transport roller).

Reference numeral 1103 denotes the leading end position of the original of the first page. Reference numeral 1105 denotes the rear end position of the original of the first page. 110
Reference numeral 4 denotes the leading edge position of the document when the transport speed is switched. Reference numeral 1106 denotes the rear end position of the original in that case. 11
Reference numerals 04 and 1106 denote positions when the document is transported at a transport speed of about １ ／ corresponding to 1103 and 1105, respectively.

In FIG. 1B, a vertical axis 1111 indicates a document conveying speed at a reading position. In FIG. 9C, the vertical axis 1117 indicates the pulling force of the document at the reading position. First, in 1103 and 1105, the document conveyance speed is as shown by a 'in the figure from the time when the leading edge of the document enters the reading position 1108 to the time when the trailing edge of the document passes through the conveying roller position 1110, and the document pulling force is This is as indicated by d 'in the figure. From the time when the trailing edge of the document passes through the transport roller position 1109 to the time when the trailing edge of the document passes through the reading position 1108, the document transport speed is as indicated by b 'in the figure, and the document pulling force is e' in the figure. As shown in FIG.

On the other hand, the transfer speeds of 1104, 11
At 06, the document transport speed is as shown in FIG. 7A and the document pulling force is shown in FIG. 6D from the time when the leading edge of the document enters the reading position 1108 to the time when the leading edge of the document enters the discharge roller position 1107. It is on the street. From the time when the leading edge of the document enters the paper discharge roller position 1107 to the time when the trailing edge of the document passes through the transport roller position 1109, the document transport speed is as shown in FIG. As shown. From the time when the rear end of the document passes through the conveying roller position 1109 to the time when the document passes through the reading position 1108, the document conveying speed is as shown in FIG. 3C, and the document pulling force is as shown in FIG.

As shown in FIG. 10, when the document conveying speed changes, the relationship between the document conveying speed and the force for pulling the document also changes.

[0013]

However, in the conventional image reading apparatus, a constant control method (motor control,
Image processing), the image was read
At the time of transmission, monochrome scanning, color scanning, low resolution reading, high resolution reading, etc., a line reading error occurred when restarting from a pause. In addition, when the number of rotations of the motor is different, the read image partially expands and contracts.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image reading apparatus, a method, and a storage medium which can obtain a clear read image in which a read line error does not occur at the time of restarting from a temporary stop.

Another object of the present invention is to provide an image reading apparatus, a method, and a storage medium which can prevent partial expansion and contraction of a read image.

[0016]

According to a first aspect of the present invention, there is provided an image reading apparatus for reading an image of a document being conveyed at an image reading position. In an image reading apparatus that is provided upstream and downstream of a reading position and includes a document transport unit that transports the document, and a driving unit that drives the document transport unit, a position of the document during the image reading is detected. And an image reading control means for controlling the image reading operation in accordance with the detected position of the document during image reading.

According to a second aspect of the present invention, in the image reading apparatus of the first aspect, the document position detecting means includes a document leading edge detecting means for detecting a leading edge of the document,
Timing means for measuring the time from when the leading edge of the document is detected, wherein the position of the document during image reading is detected based on the measured time.

In the image reading apparatus according to a third aspect, in the image reading apparatus according to the first aspect, the image reading control unit is configured to convey the original by a roller disposed upstream of the image reading position. The position, the position where the document is transported by rollers disposed downstream of the image reading position, and the position where the document is transported by both rollers disposed on the upstream side and the downstream side, The image reading operation is controlled.

According to a fourth aspect of the present invention, in the image reading apparatus according to the first, second or third aspect, the image reading control means stops the image reading operation after the image reading operation is temporarily stopped. In the case of activation, an estimating means for estimating an overshoot amount of the document at the time of the pause is provided, and the image reading operation is controlled in consideration of the estimated overshoot amount.

According to a fifth aspect of the present invention, in the image reading apparatus according to the fourth aspect, the image reading control means reads the image so as not to capture an image corresponding to the excessive amount. Thus, the image reading operation is controlled.

According to a sixth aspect of the present invention, in the image reading apparatus according to the fourth aspect, the image reading control means reverses the driving means by an amount corresponding to the overshoot amount to position the document. By controlling the reading operation of the image.

According to a seventh aspect of the present invention, in the image reading apparatus according to the first, second, or third aspect, the image reading control means controls the driving means to convey the document. The image reading operation is controlled by changing the speed.

In the image reading apparatus according to the eighth aspect, in the image reading apparatus according to the seventh aspect, the image reading control means may control the document conveying speed to be substantially independent of the state of the image reading position of the document. The driving means is controlled so as to be constant.

According to a ninth aspect of the present invention, there is provided an image reading method, wherein rollers arranged on an upstream side and a downstream side of an image reading position are driven to convey a document, and an image of the conveyed document is read at the image reading position. In the image reading method for reading, the method includes a step of detecting a position of the document during the image reading, and a step of controlling the image reading operation according to the detected position of the document.

According to a tenth aspect of the present invention, the original is conveyed by driving rollers disposed on the upstream and downstream sides of the image reading position, and the image of the conveyed original is read at the image reading position. The storage medium, which is executed by a computer that controls the image reading apparatus and stores a program for reading an image of the document, includes a step of detecting a position of the document during image reading, and a step of detecting the position of the detected document. Controlling the image reading operation according to the position.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the image reading apparatus, method and storage medium of the present invention will be described.

[First Embodiment] FIG. 1 is a diagram showing a schematic configuration of an image reading apparatus according to a first embodiment. In the figure, reference numeral 101 denotes an image scanner. Reference numeral 107 denotes an original. Reference numeral 106 denotes a paper feed roller. Reference numeral 109 denotes a separation pad.

The original 107 is separated and conveyed one by one by a feed roller 106 and a separation pad 109. 105 and 108 are a pair of conveyance rollers. The document is conveyed while being sandwiched between the conveying rollers 105 and 108.

Reference numeral 114 denotes a document leading edge detection sensor for detecting the leading edge of the document. An image sensor 104 converts an image of the original into an electric signal.
It is represented by a CD. Here, a contact type sensor that reads an image in close contact with a document is used as the image sensor, but a sensor using a document reduction optical system may be used.

The image sensor 104 includes a light source for illuminating the original, glass on which the original adheres, a lot lens array for condensing light reflected from the original, and a photoelectric conversion element for converting the condensed light into an electric signal. 102 and 103 are a pair of paper discharge rollers. Discharge roller 102 and discharge roller 1
The original is conveyed with the original 03 interposed therebetween.

Each roller 102, 103, 105, 108
And 106 are driven by a stepping motor 110. The stepping motor 110, the document leading edge detection sensor 114, and the image sensor 104 are each a CPU.
A document is conveyed and an image is read at a predetermined timing based on a signal from the document leading edge detection sensor 114.

A memory 113 temporarily stores correction data for each pixel, image data for a predetermined line, and the like. Reference numeral 111 denotes a control table stored in a memory (not shown), in which a mode related to motor control selected according to the position of the document, the number of rotations of the motor, and the like are registered. Reference numeral 116 denotes a host computer which is connected to the image scanner 101 and exchanges data. For example, a request such as a reading resolution is sent from the host computer 116 to the CPU 11 of the image scanner 101.
2 is sent to the control table 111.
Select a mode related to motor control from.

FIG. 2 is a timing chart showing a temporal change in the position of the document. In the figure, the horizontal axis 202 indicates time, and the vertical axis 201 indicates a position in the transport direction. Reference numeral 209 denotes the position of the paper feed roller 106. Reference numeral 208 denotes the position of the transport rollers (first transport rollers) 105 and 108. 2
Reference numeral 07 denotes an image reading position of the image sensor 104. 206 is a paper discharge roller (2nd transport roller) 102;
The position of 103 is shown. Reference numeral 203 denotes the leading edge position of the document,
Reference numeral 204 denotes a rear end position of the document. The image of the conveyed document is read at the image reading position 207. As shown in FIG. 2, the image reading position can be divided into three states Y1, Y2, and Y3 from the relationship with the rollers involved in document conveyance. That is, the state Y1 is the conveyance roller 105,
A state 107 is a state where the document 107 is being conveyed by 108, a state Y2 is a state where the document 107 is being conveyed by the conveying rollers 105 and 108 and the paper discharge rollers 102 and 103, and a state Y3 is a state where the document 107 is being conveyed by the paper discharge rollers 102 and 103. The document 107 is being conveyed.

FIG. 3 is a diagram showing table values in the control table 111 according to the document conveying speed and the position of the document. The control table 111 describes various table values for optimally performing motor control according to the document conveyance speed (image reading resolution) and the position of the document.

Specifically, when the motor is temporarily stopped to temporarily stop the reading operation and then restarted to restart the reading operation again, the original due to the inertia of each roller, the backlash of the gears, etc. Of the overrun (the amount of overshoot at the time of suspension) is stored in the control table 111.
Is registered as a table value. Immediately after the restart, image reading control is performed such that image data for a predetermined line indicated as a table value is not taken in.

FIGS. 4 and 5 are flow charts showing the procedure of the document conveying process. This processing program is executed by the CPU
The program is stored in a ROM in the CPU 112 and executed by the CPU 112. First, when an image reading operation start request is received from the host computer 116, a reading mode is set according to the information of the image reading resolution or the document conveyance speed (step S1). That is,
The speeds V1, V2, V3 according to the reading mode are set to the motor speed V (steps S2, S3, S4).

The motor is driven at the motor speed V to start feeding and transporting the original (step S5). It waits for the detection of the leading edge of the document (step S6). When the leading edge of the document is detected, a timer used for estimating the position of the subsequent document is started (step S7).

Then, the document position Y is calculated from the document conveying speed (motor speed) V and the time of the timer T (step S).
8). Document position Y is image reading position state Y1, Y
2 or Y3 (step S9),
Based on the states Y1, Y2, Y3 and the document conveying speed V,
A table value of the control table 111 is selected and read (steps S10, S11, S12).

Thereafter, it is determined whether there is a pause request (step S13). If there is no pause request, the process returns to step S8. The number M of overrun lines is obtained as a table value according to the speed V and the time of the timer T (step S14). Then, it is determined whether or not there is a restart request (step S15). If there is a restart request, data read from the control table 111 (here, data indicating that there is an overrun for M lines)
, An image reading operation is performed so as not to take in image data for M lines (step S16).

Then, it is determined whether or not the image reading operation for one page has been completed (step S17). If the image reading operation for one page has not been completed, the process returns to step S6. On the other hand, if the image reading operation for one page has been completed, it is determined whether or not all reading operations have been completed. (Step S18) If all reading operations have not been completed, the process returns to step S6. On the other hand, if all reading operations have been completed, post-processing is performed (step S19), and the process ends.

As described above, it is possible to appropriately control the pause and restart of the image reading operation based on the position of the document and the document conveying speed, and it is possible to prevent a reading error at the time of restart.

It should be noted that, instead of preventing the image for M lines from being captured in step S16, it is also possible to control to return the position of the original for M lines which has gone too far. FIG. 6 is a flowchart showing a part of another document transport processing procedure. This process corresponds to FIG.
Following the processing of. That is, when a restart request is made in step S15, the motor is reversed for M lines (step S16A), and then the motor is restarted (step S16B). Then, the processing after step S17 is performed. Thereby, the restart control can be appropriately performed.

[Second Embodiment] In the first embodiment, when restarting from a temporary stop depending on the position of the document, a reading error at the time of restarting is prevented. In the second embodiment, the number of rotations of the motor is changed according to the position of the document, thereby preventing partial expansion and contraction of the read image. The configuration of the image reading apparatus according to the second embodiment is the same as that of the first embodiment.

FIG. 7 is a timing chart showing a change over time in the position of the document and the motor rotation speed in the second embodiment. In FIG. 9A, the horizontal axis 502 indicates time, and the vertical axis 501 indicates a position in the transport direction. Reference numeral 509 denotes a paper feed roller position, 508 denotes a transport roller (1st transport roller) position, 507 denotes an image reading position by an image sensor, and 506 denotes a paper discharge roller (2nd transport roller) position.

Reference numeral 503 denotes the position of the leading edge of the original of the first page.
Reference numeral 504 denotes a rear end position of the original of the first page. Reference numeral 520 indicates the leading edge position of the document of the second page. The first page of the conveyed document is read during the image reading period 505, and the second page of the document is read during the image reading period 521.

In FIG. 5B, the vertical axis 513 indicates the motor rotation speed (rotation speed). The horizontal axis indicates time. Conventionally, the conveyance speed of the document during the image reading period is different (see FIGS. 9 and 10). However, in the second embodiment, the conveyance speed of the document (image reading speed) during the image reading period is constant. In addition, the rotation speed of the motor is changed to a rotation speed of 5 in accordance with the image reading position states Y1, Y2, and Y3.
Rotation speeds 523, 524, 5 without significant change from 22
25, the image reading period 5
The document transport speed at 05 is made substantially constant, and partial expansion and contraction of the read image is prevented. Even in the second page manuscript,
Similarly, in the image reading period 521, the rotation speed of the motor is switched stepwise from the rotation speed 526 corresponding to the state of the image reading position to the rotation speeds 527 and 528 without much change.

Since these motor speeds are changed according to the reading mode selected in step S1, the table values using the control table 111 shown in FIG. 3 can be used.

As described above, in the second embodiment, the number of rotations of the motor is changed according to the position of the original, and the conveying speed of the original at the image reading position is made substantially constant. No beautiful images can be obtained at low cost. Further, by using the first embodiment together, it is possible to realize more accurate reading.

The present invention may be applied to a system constituted by a plurality of devices, or may be applied to an apparatus constituted by one device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In this case, by reading out a storage medium storing a program represented by software for achieving the present invention into a system or an apparatus, the system or the apparatus can enjoy the effects of the present invention.

FIG. 8 is a diagram showing a memory map of the ROM in the CPU 112 as a storage medium. The ROM in the CPU 112 stores a document transport processing program module shown in the flowcharts of FIGS. 4 and 5, a document transport processing program module shown in the flowchart of FIG. 6, and the like.

The storage medium for supplying the program module is not limited to the ROM, but may be a floppy disk, a hard disk, an optical disk, a magneto-optical disk,
A D-ROM, a CD-R, a DVD, a nonvolatile memory card, or the like can be used.

[0052]

According to the present invention, by performing motor control at the time of restarting from a temporary stop depending on the position of a document, reading errors at the time of restarting can be prevented, and reading line errors at the time of restarting from a temporary stop can be prevented. A clear read image that does not occur can be obtained.

Further, by changing the number of rotations of the motor according to the position of the original, partial expansion and contraction of the read image can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an image reading apparatus according to a first embodiment.

FIG. 2 is a timing chart showing a temporal change in the position of a document.

FIG. 3 is a diagram showing table values according to a document conveyance speed and a document position in a control table 111;

FIG. 4 is a flowchart illustrating a document transport processing procedure.

FIG. 5 is a flowchart illustrating a document transport processing procedure following FIG. 4;

FIG. 6 is a flowchart illustrating a part of another document transport processing procedure.

FIG. 7 is a timing chart showing a change over time in a position of a document and a motor rotation speed in the second embodiment.

FIG. 8 is a diagram showing a memory map of a ROM in a CPU 112 as a storage medium.

FIG. 9 is a timing chart showing a time change of a document position, a document conveying speed, and a document pulling force in a conventional image reading apparatus.

FIG. 10 is a timing chart showing a time change of a document position, a document conveyance speed, and a document pulling force in another conventional image reading apparatus.

[Explanation of symbols]

 101 Scanner 102, 103 Discharge roller 104 Image sensor 105, 108 Transport roller 106 Feed roller 107 Document 110 Stepping motor 111 Control table 112 CPU 114 Document leading edge detection sensor 115 Timer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H108 AA14 CB01 FA01 FA29 FA31 5C062 AA02 AA05 AA13 AB02 AB17 AB30 AB32 AB41 AB42 AC12 AC13 AC14 AC66 AF06 BA00 5C072 AA01 BA15 BA17 FB23 NA01 NA05 NA07 RA04 UA11 UA13 UA14 XA

Claims (10)

[Claims] An image reading unit that reads an image of a document being transported at an image reading position; and an image reading unit that is arranged upstream and downstream of the image reading position.
An image reading apparatus comprising: a document feeder that feeds the document; and a driving unit that drives the document feeder. A document position detector that detects a position of the document during image reading; and the detected image. An image reading apparatus, comprising: image reading control means for controlling an image reading operation according to a position of a document being read. 2. The document position detecting means comprises: a document leading edge detecting means for detecting a leading edge of the document; and a timer means for measuring a time from when the leading edge of the document is detected. 2. The image reading apparatus according to claim 1, wherein a position of the document during image reading is detected based on the information. 3. The image reading control means includes: a position at which the document is conveyed by a roller disposed upstream of the image reading position; and a conveyance of the document by a roller disposed downstream of the image reading position. 2. The image reading operation according to claim 1, wherein the image reading operation is controlled in accordance with a position where the document is conveyed by a roller and a position where the document is conveyed by both rollers arranged on the upstream side and the downstream side. apparatus. 4. The image reading control means includes estimating means for estimating an overshoot amount of the document when the image reading operation is paused and restarted after the pausing, and the estimated overshoot is provided. 4. The image reading apparatus according to claim 1, wherein the image reading operation is controlled in consideration of an amount. 5. The image reading control unit according to claim 4, wherein the image reading control unit controls the image reading operation by reading the image so as not to capture an image corresponding to the overshoot amount. Image reading device. 6. The image reading control unit controls the image reading operation by reversing the driving unit and returning the position of the document by an amount corresponding to the overshoot amount. Item 5. The image reading device according to Item 4. 7. The image reading control unit controls the driving unit to change a conveyance speed of the document,
4. The image reading apparatus according to claim 1, wherein the image reading operation is controlled. 8. The image reading control unit controls the driving unit such that the conveying speed of the document is substantially constant irrespective of the state of the image reading position of the document. 8. The image reading device according to 7. 9. An image reading method for driving a roller disposed upstream and downstream of an image reading position to convey a document and reading an image of the conveyed document at the image reading position. An image reading method, comprising: a step of detecting a position of a document in the document; and a step of controlling the image reading operation in accordance with the detected position of the document. 10. A computer for controlling an image reading apparatus that drives a roller disposed upstream and downstream of an image reading position to convey a document and reads an image of the conveyed document at the image reading position. A storage medium that is executed and stores a program for reading the image of the document, the program comprising: a procedure for detecting a position of the document during reading of the image; and Controlling a reading operation.