JP2001309125A - Image reader, control method for the image reader, and medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader, a control method for the image reader and a medium by which an original read position can properly be set. SOLUTION: A read position at which an original supplied by a draft feeder is read in a state in which an optical scanning means is stopped at a prescribed read position is set on the basis of a result of reading a prescribed mark described on an original guide plate of the draft feeder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading technique in a copying machine, a scanner, a facsimile machine and the like.
In particular, the present invention relates to a technique of setting a document reading position when reading a document while moving the document while the optical scanning unit is stopped, that is, a stop position of the optical scanning unit.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a scanner, a facsimile apparatus, etc., an automatic document feeder (ADF) has : Auto Document
2. Description of the Related Art There is known an apparatus having a so-called flow reading function of reading a document (document information and document image) while moving the document by a feeder. The ADF is generally provided as an option, and is configured to be detachable from the document reading apparatus main body.

In this type of image forming apparatus, the positional relationship between the ADF and the document reading position in the document reading device main body is A
The target positional relationship may not be attained due to the mounting position of the DF or the variation of each component.

As a method of adjusting the positional relationship, for example, as disclosed in Japanese Patent Application Laid-Open No. Hei 6-178064, the optical scanning unit is sequentially stopped near the transport roller (platen roller) of the ADF and the transport roller is stopped. There is known a method of irradiating light to a document, reading the reflected light by a document reading apparatus main body, and setting the stop position where the reflected light is maximum as the document reading position.

[0005]

However, in the above-mentioned conventional method, an appropriate document reading position is erroneously detected due to a noise factor such as contamination of the conveying roller and electric noise of the document reading apparatus main body. The problem that the image rubber tip shifts and the image blurring is degraded due to defocusing has occurred.

The present invention has been made in view of such circumstances, and an object thereof is to make it possible to appropriately set a document reading position.

[0007]

In order to solve the above problems, the present invention provides an optical scanning means for optically scanning an original and a photoelectric conversion means for photoelectrically converting an optical image obtained by the optical scanning means. An image reading apparatus having a reading section including a document feeding apparatus for automatically feeding a document, wherein the light scanning unit is moved to a predetermined reading position for the document being fed by the document feeding apparatus. There is provided setting means for setting the reading position when reading in a stopped state based on a reading result obtained by reading a predetermined mark written on the document feeder by the reading unit.

According to another aspect of the present invention, there is provided a reading unit including an optical scanning unit for optically scanning an original and a photoelectric conversion unit for photoelectrically converting an optical image obtained by the optical scanning unit. A method for controlling an image reading apparatus in which a document feeding device for detachably feeding a document is detachable, wherein a document being fed by the document feeding device is read in a state where the optical scanning unit is stopped at a predetermined reading position. The reading position is set based on a result of reading a predetermined mark written on the document feeding device by the reading unit.

According to another aspect of the present invention, there is provided a reading unit including optical scanning means for optically scanning an original and photoelectric conversion means for photoelectrically converting an optical image obtained by the optical scanning means. In a computer-readable medium applicable to an image reading device in which a document feeding device for feeding a document is detachably attached, the optical scanning unit stops the document being fed by the document feeding device at a predetermined reading position. The reading position when reading in a state where the document is read is set based on a result of reading a predetermined mark written on the document feeder by the reading unit.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a schematic configuration of a digital scanner to which the present invention is applied.
This digital scanner comprises a scanner body 105 and an ADF detachably mounted on the scanner body 105.
101.

The ADF 101 is for setting the original document 102.
Is conveyed to the original platen glass 106 of the scanner main body 105 by the conveying roller 103 and collected. At this time, the original 102
Is a document guide plate 104 attached to the ADF 101
Then, the document passes between the document table glass 106 of the scanner body 105 and the scanner body 105 optically scans the document information during the passage process to read document information.

That is, the scanner body 105 includes a lamp 107 for irradiating light to the original surface, and a mirror 108 for guiding the reflected light from the original 102 corresponding to the light emitted from the lamp 107 to the lens 116 and the CCD 117. , 1
It has 10,111. Lamp 107 and mirror 10
8 is attached to the optical table 109, and mirrors 110, 11
1 is attached to the optical bench 112.

The optical tables 109 and 112 are connected to the wire 1
The motor 13 is connected to a motor 114, and is controlled to move in parallel with the original table glass 106 by the rotation of the motor 114. The position sensor 115 is a sensor for detecting the home position of the optical table 109. The motor 114 is rotated forward and backward with reference to the position of the position sensor 115, so that the optical tables 109 and 112 are moved and the original is moved. An original on the table glass 106 is optically scanned.

The motor 114 is constituted by a stepping motor. An encoder 302 (see FIG. 3) is connected to the motor 114. The output of the encoder 302 makes it possible to recognize how many pulses the optical benches 109 and 112 have moved. In other words, the position sensor 115 and the encoder 302
Optical tables 109 and 112 by the encoder pulse from
It is possible to grasp the position of.

Light reflected from the original is reflected by mirrors 108 and 11.
0, 111 to the lens 116 and the lens 11
The light is condensed on the CCD 117 by 6. CCD117
Converts the reflected light reflecting the document information photoelectrically, and outputs it as an electronic image signal.

Under such a configuration, with the optical table 109 stopped at the document reading position, the ADF 101 reads the document information while transporting the document by the ADF 101, and the document is placed on the platen glass 106. The document information can be read in two modes: a document table glass document reading mode in which the document information is read while the optical tables 109 and 112 are fixedly moved and the optical tables 109 and 112 are moved in the sub-scanning direction.

FIG. 2 is a diagram showing the configuration of the document guide plate 104 used in the present embodiment. Document guide plate 104
A is for guiding the document feeding direction by the ADF 105, and generally white is used to prevent show-through when reading the document. This white document guide plate 10
4, a black reading position mark 201 for setting a normal document reading position in the ADF document reading mode is described.

The reading position mark 201 is linearly written at the center of the document guide plate 104 from the downstream side to the upstream side in the document conveying direction (sub-scanning direction). When the scanning is performed while moving from the sensor 115 side to the upstream side of the document conveyance, the position (the position indicated by the broken line in FIG. 2) which becomes the end 201a of the reading position mark 201 indicates the normal reading position. Has become.

The width (line width) of the reading position mark 201 in the main scanning direction is preferably set to a somewhat large width in order to easily distinguish the mark from dust and the like.
7 has a width equal to or larger than a plurality of pixels (n pixels). Further, the width (line length) in the sub-scanning direction is desirably larger than the width of the stop accuracy of the motor 114 in order to prevent erroneous detection of the reading position mark 201 due to variation in the stop accuracy of the motor 114. In the embodiment, the document guide plate 1
04 is about 1/2 of the width in the sub-scanning direction.

FIG. 3 is a block diagram showing a schematic configuration of a control system of the digital scanner.

A transport roller 103 for transporting the original 102;
Lamp 107 for irradiating light to the original surface, optical bench 109, 1
Motor 12 for moving the original 12 in the sub-scanning direction and scanning the original
4. CCD 117 for photoelectrically converting reflected light from the document surface;
A / D conversion circuit 301 for A / D converting the output signal of CCD 117, encoder 30 connected to motor 114
2. Lamp 107 for irradiating the original with light, ADF1
01, a position sensor 115 for positioning the optical table 109 at the home position, a backup RAM 303 for setting a normal document reading position in the ADF document reading mode,
And a scanner controller 304.

Note that the scanner controller 304 includes a ROM 304a in which various programs such as a program corresponding to a flowchart of FIG. 4 described later are stored.

The scanner controller 304 grasps the positions of the optical tables 109 and 112 based on the encoder output and the output signal from the position sensor 115, and based on the output signal of the CCD 117 digitized by the A / D conversion circuit 301. Then, the presence or absence and position of the reading position mark 201 are detected, and the detected position of the reading position mark 201 is stored (set) in the backup RAM 303 as a normal document reading position in the ADF document reading mode.

The operation of detecting and setting the document reading position is performed by A
The operation is performed when the DF 101 is attached to the scanner main body 105, the reading operation in the ADF original reading mode is performed every time the operator instructs, or when the power of the digital scanner is turned on. You may. In any case, each time an original is read, the original reading position is not detected and set before each original reading operation, so that the original can be read quickly. It is. This document reading position detection
It is preferable that the timing of the setting can be arbitrarily selected by the operator.

It is also possible to execute the detection and setting of the document reading position at an arbitrary timing by operating a predetermined key, for example. This form is, for example, AD
The connection mechanism between the F101 and the scanner body 105 is an ADF
This is particularly useful when the ADF 101 and the scanner main body 105 may be displaced when the user touches the 101.

Next, the process of detecting and setting the document reading position will be described with reference to the flowchart of FIG.

The scanner controller 304 has a ROM 4
First, the motor 114 is driven and controlled in accordance with the program stored in the document guide plate 104a from the home position for a preset number of pulses from the home position.
The optical benches 109 and 112 are moved in the direction of and stopped (step S1). The movement amount at this time is the original guide plate 1
The moving amount is such that the optical bench 109 moves to a position where a part of the reading position mark 201 described in 04 can be surely read.

Next, the scanner controller 304 turns on the lamp 107 and outputs from the CCD 117
The signal converted into a digital signal by the / D conversion circuit 301 is read (steps S2 and S3). This read signal is usually as shown in FIG. That is, the read signal is
The portion corresponding to the black reading position mark 201 is Low.
Level, and the other parts corresponding to the white document guide plate 104 are at the high level.

Next, the scanner controller 304 determines whether there is a read signal equal to or less than a predetermined threshold (step S4). As a result, if there is a read signal equal to or smaller than the threshold, it is determined whether the read signal equal to or smaller than the threshold is continuous for a predetermined number of pixels (here, n pixels) (step S5).

As a result, if the read signal equal to or less than the threshold value is continuous for a predetermined number of pixels, it is considered that the read position mark 201 has been read, and the motor 114 is rotated by n pulses to move the optical table 109 to the upstream side. (Step S
6) Return to step S3. That is, until the reading position mark 201 is no longer detected, the reading position mark 201 is detected on the upstream side of the document conveying path.

On the other hand, if the read signals equal to or less than the threshold value are not continuous for a predetermined number of pixels, it is assumed that the read signals equal to or less than the threshold value correspond to noise components such as dust, and the process proceeds to step S7.

If it is determined in step S4 that there is no read signal image below the threshold (see FIG. 5B), or if the read signal below the threshold is not continuous for a predetermined number of pixels in step S5. Means that the upstream end 201a of the reading position mark 201 has been read, as can be inferred from the above description. Therefore, the number of drive pulses of the motor 114 from the home position to the present (i.e.,
The movement amount of the optical table 109 is stored in the backup RAM 303 as document reading position data (step S).
7), end.

As described above, since the original reading position is set by detecting the reading position mark 201 written on the original guide plate 104, the original reading position can be appropriately set without being affected by dust, dirt, and the like. Can be set,
This makes it possible to prevent image deterioration such as displacement of the leading end of the image at the time of reading the original and defocusing.

[Second Embodiment] In the second embodiment,
As shown in FIG. 6, a predetermined distance (for example, for n pulses) from the upstream end 201a of the reading position mark 201 to the upstream.
The distant position (the position indicated by the broken line) is set as the document reading position in the ADF mode.

As described above, by setting a position distant from the reading position mark 201 as the document reading position, it is possible to prevent the reading position mark 201 from showing off during actual document reading.

The present invention is not limited to the above-described embodiment. For example, the reading position mark 201 is described not upstream of the central portion of the document guide plate 104 but upstream of the central portion. It is also possible to set the document reading position by detecting from the upstream side to the downstream side. The reading position mark 201 is located on the original guide plate 1.
For example, it may be written in an area on the document guide plate 104 that is outside the central area of the document 04 and that is outside the conveyance area of the largest readable document.

Further, the reading position mark 201
It is also possible to write on a portion other than the document guide plate 104 on the document 101. However, in this case, it is natural that a reading position mark is written in a light irradiable area on the document conveyance path in the ADF mode, but the document is read while the document is lifted from the conveyance path and the image is read. It is desirable to write a reading position mark near the transport roller 103 as much as possible so as not to deteriorate.

[0039]

As described above, according to the present invention,
The document reading position can be set appropriately without being influenced by noise factors such as contamination of the conveying roller and electric noise of the document reading apparatus main body.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a digital scanner to which the present invention has been applied.

FIG. 2 is an explanatory diagram for explaining a reading position mark and a document reading position according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a control system of the digital scanner in FIG. 1;

FIG. 4 is a flowchart illustrating a document reading position setting process according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a read signal for explaining a method of detecting a read position mark.

FIG. 6 is an explanatory diagram for explaining a reading position mark and a document reading position according to a second embodiment of the present invention.

[Explanation of symbols]

 101 ADF 103 Conveying roller 104 Document guide plate 105 Scanner body 107 Lamp 114 Motor 115 Position sensor 117 CCD 201 Reading position mark 201a Edge of reading position mark 303 Backup RAM 304 Scanner controller 304a ROM

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H108 AA01 CB01 FA03 FA21 FA34 5B047 AA01 BA01 BB02 BC05 BC09 BC11 BC14 CB09 CB22 DB01 DC06 5C072 AA01 BA15 CA02 DA02 DA04 EA05 NA04 RA04 RA07 UA06 UA11 XA01

Claims (13)

[Claims] An optical scanning unit for optically scanning the original; and a photoelectric conversion unit for photoelectrically converting an optical image obtained by the optical scanning unit. The original is automatically fed. In an image reading apparatus in which a document feeding device is detachable, the reading position when reading the document being fed by the document feeding device with the optical scanning unit stopped at a predetermined reading position is the document. An image reading apparatus comprising: setting means for setting a predetermined mark written on a feeding device based on a result of reading by the reading unit. 2. The method according to claim 1, wherein the setting unit detects an end of the mark by reading the mark by the reading unit while moving the optical scanning unit from a predetermined position, and detects an end of the mark. The moving amount of the optical scanning means at a point in time is set as the reading position.
The image reading device according to claim 1. 3. The setting unit detects an end of the mark by reading the mark by the reading unit while moving the optical scanning unit from a predetermined position, and detects an end of the mark. 2. The image reading apparatus according to claim 1, wherein a movement amount slightly larger than a movement amount of the optical scanning unit at a time is set as the reading position. 4. The image according to claim 1, wherein a width of the mark in the main scanning direction of the light scanning unit is equal to or more than a predetermined number of pixels of the photoelectric conversion unit. Reader. 5. The mark is considered to have been read when an image signal of a signal level corresponding to the mark is continuously obtained by the photoelectric conversion unit for at least the predetermined plurality of pixels. 5. The image reading apparatus according to claim 4, wherein: 6. The image reading apparatus according to claim 1, wherein a width of the mark in the sub-scanning direction of the optical scanning unit is larger than a width of stopping accuracy of the optical scanning unit. . 7. The mark according to claim 1, wherein the mark is linear and its longitudinal direction is parallel to the sub-scanning direction of the optical scanning unit. The image reading device according to claim 1. 8. The image reading apparatus according to claim 1, wherein the mark is provided on a document guide plate for guiding a direction of feeding the document. 9. The image according to claim 8, wherein the mark is written from an end on the document guide plate on a downstream side of the optical scanning unit in a sub-scanning direction toward an upstream side. Reader. 10. The apparatus according to claim 1, wherein said setting means performs setting processing of said reading position when power is turned on.
The image reading device according to any one of the above. 11. The image forming apparatus according to claim 1, wherein the setting unit performs the setting process of the reading position when an image reading process using the document feeder is instructed. Image reading device. 12. A reading section comprising optical scanning means for optically scanning an original and photoelectric conversion means for photoelectrically converting an optical image obtained by the optical scanning means, and automatically feeding the original. In a method for controlling an image reading device in which a document feeding device is detachable, the reading position when reading the document being fed by the document feeding device with the optical scanning unit stopped at a predetermined reading position is determined. A method for setting a predetermined mark on the document feeder based on a result of reading by the reading unit. 13. A reading unit including optical scanning means for optically scanning a document and photoelectric conversion means for photoelectrically converting an optical image obtained by the optical scanning means, and automatically feeds the document. In a computer-readable medium applicable to an image reading device in which a document feeding device is detachable, a document being fed by the document feeding device is read with the optical scanning unit stopped at a predetermined reading position. A medium having contents for setting the reading position in the case based on a reading result obtained by reading a predetermined mark written on the document feeding device by the reading unit.