JP2000174991A - Image reader and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader that can conduct image read scanning corresponding to an original width while omitting unnecessary read scanning at the outside of an original area, prevent expansion/contraction of an image without the use of an image processing means and also prevent a change in image density, and to provide an image forming device. SOLUTION: The image reader is provided with a positioning means that decides positions of originals 102, 103 by using positions, at which read start signals 104, 110 from a line image sensor to start reading for each line are received first, for reference positions, and a detection means that detects original widths A, B of the originals 102, 103 positioned by the positioning means. The image reader applies read scanning to the originals 102, 103, based on the read start signals 104, 110 to read the originals at a time interval of the read start signals corresponding to the original widths A, B, omits unnecessary read scanning at the outside of the original area and conducts read scanning corresponding to the original widths A, B and is also provided with a drive control means, a luminous quantity control means and an image density adjustment means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image scanner (also referred to as an image reading device) using a line image sensor, and a facsimile, an MFP having the image scanner,
The present invention relates to an image reading device such as a copying machine and an image forming device.

[0002]

2. Description of the Related Art Conventionally, an image scanner using a line image sensor, a facsimile having an image scanner,
In MFPs, copiers, and the like, the time interval of the read start signal of the line image sensor is not changed in accordance with the document width, not to mention the case where the document width dimension is not detected.

[0003]

However, according to the above-mentioned prior art, the time interval of the read start signal of the line image sensor is not changed in accordance with the width of the original. When the size is smaller than the size of the line image sensor, the image reading operation has been performed to the outside of the document area. For this reason, even when the document width dimension is smaller than the dimension of the line image sensor, it has not been possible to shorten the document reading time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and enables an image reading scan corresponding to a document width by omitting unnecessary reading scans outside a document area. It is an object of the present invention to provide an image reading apparatus and an image forming apparatus capable of preventing expansion and contraction of an image and preventing a change in image density.

[0005]

The present invention can solve the above-mentioned problems by providing the following constitution.

(1) In an image reading apparatus having a light source and a line image sensor for reading a document by the light source, a position where a reading start signal for starting reading for each line by the line image sensor is first input is used as a reference. Positioning means for determining the position of the document, detecting means for detecting the document width dimension of the document positioned by the positioning means, and the reading start signal read at a time interval of a reading start signal corresponding to the document width dimension, An image reading apparatus for reading and scanning the original, omitting unnecessary reading and scanning outside the original area, and performing reading and scanning corresponding to the width of the original.

(2) In the image reading apparatus according to the above (1), the moving speed for reading and scanning of the line image sensor and the moving speed for feeding the original document correspond to the time interval of the reading start signal. An image reading apparatus, comprising: a driving control unit corresponding to a relative moving speed of the image reading apparatus.

(3) In the image reading device according to any one of (1) and (2), the amount of light received by the document from the light source is controlled in accordance with the time interval of the reading start signal. An image reading device comprising light amount control means.

(4) In the image reading device according to any one of (1) and (2), the sensor output from the line image sensor is varied according to a time interval of the reading start signal, An image reading apparatus, comprising: image density adjusting means for adjusting the density of an image read from the document.

(5) An image forming apparatus comprising the image reading apparatus according to any one of (1), (2), (3) and (4).

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described below.

FIG. 1 is an explanatory view showing an original and input / output signals to and from a line image sensor corresponding to the line image sensor and the original width. FIG. 2 is a curve showing the relationship between the original width and the time interval of a reading start signal. 5 is a graph showing a relationship between a relative movement speed between the line image sensor and the document and a light amount irradiating the document with respect to a time interval of the reading start signal.

(First Embodiment) In FIG.
Denotes an image reading unit using a line image sensor, 102 denotes a document having a width A, and 103 denotes a document having a width B. Reference numeral 104 denotes a reading start signal for performing image reading scanning on the document 102 having the width A, and reference numeral 105 in the reading start signal 104 denotes a time interval of the reading start signal at the time of image reading scanning. 106 is a clock signal supplied to the image reading unit 101,
Reference numeral 107 denotes a sensor output output from the image reading unit 101. In the sensor output 107, 108 is the sensor output of the nth line, and 109 is the sensor output of the (n + 1) th line. Reference numeral 110 denotes a reading start signal when performing image reading scanning on the document 103 having the width B, and reference numeral 111 in the reading start signal 110 denotes a time interval of the reading start signal during image reading scanning.

Referring to FIG. 2, reference numeral 201 denotes a graph representing data for acquiring and determining the time interval of a reading start signal corresponding to the information based on the information on the document width (A or B). 202 is a graph representing data for acquiring and determining the relative movement speed between the line image sensor and the document corresponding to the information based on the information on the time interval of the reading start signal, represented by a curve. , 2
Reference numeral 03 denotes a graph representing data for acquiring and determining the amount of light for irradiating the original corresponding to the information based on the information on the time interval of the reading start signal, represented by a curve.

When performing image reading scanning on a document 102 having a width A, the image reading unit 101
In FIG. 1, a sensor output 107 is sequentially emitted from the left side in FIG. 1 in response to the reading start signal 104 for each line.

At this time, the time interval 105 of the read start signal in the read start signal 104 when reading the original 102 having the width A corresponds to the original width A of the original 102. At the same time, the image reading unit 101 and the document 102 relatively move in the vertical direction in FIG. 1, and perform reading scanning of the (n + 1) th line after reading scanning of the nth line. Image reading unit 101 and document 102
The relative movement speed and the amount of light irradiating the document are obtained and determined from the corresponding points on the data curve shown in FIG. 2 based on the information on the time interval 105 of the reading start signal.

When reading an image of the document 103 having the width B, the image reading unit 101 sequentially outputs a sensor output 107 from the left side as viewed in FIG.

At this time, the time interval 111 of the reading start signal in the reading start signal 110 when reading the document 103 having the width B corresponds to the document width B of the document 103. At the same time, the image reading unit 101 and the document 103 relatively move in the vertical direction in FIG. 1, and perform reading scanning of the (n + 1) th line after reading scanning of the nth line. Image reading unit 101 and original 103
The relative movement speed and the amount of light irradiating the document are determined from the corresponding points on the data curve shown in FIG. 2 based on the information of the time interval 111 of the reading start signal.

When an image is read from the original 102 having the width A or the original 103 having the width B, unnecessary scanning outside the original area is omitted, and
Reading scan is performed corresponding to the area of No. 3.

Comparing each case, the document 103 having the width B has a smaller document width than the document 102 having the width A, so that the time interval of the reading start signal is reduced. The image reading time can be reduced by increasing the relative movement speed between the image reading unit 101 and the originals 102 and 103.

(Second Embodiment) In the second embodiment,
In the case where the light amounts irradiating the originals 102 and 103 are not to be made to correspond to the time intervals 105 and 111 of the reading start signal, the sensor output 107 is converted into reference data for density conversion in an image forming unit based on the sensor output 107. , The image density is adjusted by corresponding to the time interval of the reading start signal.

Further, by omitting unnecessary scanning for reading outside the document area, the image reading time can be reduced.

(Third Embodiment) In the third embodiment,
When the relative movement speed between the line image sensor of the image reading unit 101 and the originals 102 and 103 is not made to correspond to the time intervals 105 and 111 of the reading start signal, the image forming unit based on the sensor output 107 The line image sensor and the document 10
By making the enlargement / reduction ratio in the direction of relative movement with respect to 2, 103 correspond to the time intervals 105, 111 of the reading start signal, image expansion and contraction can be prevented.

Also, as in the above-described embodiment, unnecessary reading scanning outside the document area is omitted, so that the image reading time can be reduced.

[0025]

According to the present invention, means for driving the line image sensor based on the time interval of the read start signal for each line corresponding to the document width, and the time of the read start signal for each line corresponding to the document width A sheet feed type image scanner based on the interval information and a means for feeding a document in a facsimile, MFP, or copier using the image scanner in correspondence with a document feed speed, or a flatbed type image scanner Means for sending the image reading unit in a facsimile, MFP, or copier using the same image scanner, and a time interval of a read start signal for each line corresponding to the document width Current value for driving the light source to give an appropriate amount of light from the light source for irradiating the original, based on the information of With a structure in which a means for controlling the light source in correspondence with the lighting time rate of the light source,
It is possible to omit unnecessary reading scanning outside the document area to enable image reading scanning corresponding to the document width, to prevent the image from expanding and contracting without using image processing means, and to provide an effect of preventing a change in image density. .

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an input / output signal to a line image sensor corresponding to a document, a line image sensor, and a document width dimension.

FIG. 2 is a graph showing the relationship between the width of a document and the time interval of a reading start signal, and the relationship between the time interval of a reading start signal, the relative moving speed of the line image sensor and the document, and the amount of light irradiating the document. Graph showing the curves shown

DESCRIPTION OF SYMBOLS 101 Image reading unit 102 Document of width A 103 Document of width B 104 Reading start signal 105 Time interval of reading start signal 106 Clock signal 107 Sensor output 108 Sensor output of n-th line 109 Sensor of n + 1st line Sensor output 110 Reading start signal 111 Time interval of reading start signal 201 Graph showing data for acquiring and determining the time interval of reading start signal corresponding to the information based on the information of the document width dimension (A or B) 202 Based on the information on the time interval of the reading start signal, a graph 203 showing data for acquiring and determining the relative moving speed between the line image sensor and the document corresponding to the information, based on the information on the time interval of the reading start signal, To determine the amount of light to irradiate the document corresponding to the information Graph showing data

Claims (5)

[Claims] 1. An image reading apparatus comprising: a light source; and a line image sensor for reading a document by using the light source, wherein the line image sensor receives a read start signal for starting reading line by line with reference to a first input position. Positioning means for determining the position of the document, detecting means for detecting a document width dimension of the document positioned by the positioning means, and the reading start signal read at a time interval of a reading start signal corresponding to the document width dimension, An image reading apparatus which scans a document, omits unnecessary reading scanning outside the document area, and performs reading scanning corresponding to the document width. 2. The image reading apparatus according to claim 1, wherein a moving speed for reading and scanning of the line image sensor and a moving speed for feeding the document are relative to a time interval of the reading start signal. An image reading device comprising a drive control means corresponding to a moving speed. 3. The image reading device according to claim 1, wherein a light amount control unit that controls a light amount received by the document from the light source in accordance with a time interval of the reading start signal. An image reading device comprising: 4. The image reading apparatus according to claim 1, wherein a sensor output from said line image sensor is changed in accordance with a time interval of said reading start signal, and said image reading device reads said original from said document. An image reading apparatus comprising an image density adjusting unit for adjusting a read image density. 5. An image forming apparatus comprising the image reading apparatus according to claim 1.