JP3265584B2 - Image reading device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus (hereinafter, also referred to as an "apparatus"), and more particularly, to a reduction in reading accuracy of a color image due to distortion of the apparatus due to poor flatness of an installation place of the apparatus. And an image reading apparatus capable of reading a color image with high accuracy.

[0002]

2. Description of the Related Art Conventionally, in a color image reading apparatus, color image information on a document surface is transmitted from, for example, three line sensors (CCD) or the like via optical members such as an imaging lens and a diffraction grating as color separation means. An image is formed on the light receiving means surface, and color image information is digitally read using an output signal from the line sensor at this time.

In such a color image reading apparatus, a line sensor is formed in the vicinity of the document surface to prevent a light beam from a document surface different from the document surface to be read from entering the line sensor surface as noise light. And a slit having a long opening in the same direction as the arrangement direction of the pixels. When assembling the apparatus, the relative position between the slit and the line sensor is adjusted.

Generally, in a color image reading apparatus, in a so-called monolithic three-line sensor provided on the same substrate surface as three line sensors as light receiving means, the interval between lines is set to be as small as about 100 to 200 μm. Correspondingly, the opening width of the above-mentioned slit is also about 1-2 mm, which is a considerably narrow opening shape.

Therefore, in order to read a color image with high accuracy by using an output signal from the light receiving means, it is necessary to perform high-precision relative positioning between the slit and the three-line sensor. .

Generally, the alignment at this time is performed when assembling the color image reading apparatus. That is, high precision is performed using a jig or the like for optical adjustment in a factory equipped with facilities.

[0007]

However, when a color image reading apparatus is installed and used in the market, the installation location may be poor in flatness or inclined, and the installation conditions may be poor.

When the apparatus is installed in such a place, for example, there is a problem that the entire apparatus is distorted, the relative positional relationship between the slit and the three-line sensor is shifted, and the color image reading accuracy is reduced. Come.

In particular, when a light beam from a color image is separated into, for example, three color lights of R (red), G (green), and B (blue) by color separation means, and a color image is read based on the three color lights,
It becomes very difficult to read digitally and with high precision in a well-balanced manner with each color light.

The present invention corrects a color image with high accuracy by using a posture adjusting means to correct a deviation of a relative positional relationship between a slit and a light receiving means caused by poor installation conditions of a color image reading apparatus. It is an object of the present invention to provide a color image reading apparatus having a posture adjusting means capable of reading.

[0011]

According to the first aspect of the present invention, there is provided an image reading apparatus, comprising: a document placing portion; a slit for restricting reflected light from the document placed on the document placing portion; A line sensor for receiving light, a display for displaying information on a relative positional relationship between the slit and the line sensor using an output of the line sensor when reading a document of uniform density. Means, and adjusting means for adjusting a relative positional relationship between the slit and the line sensor, wherein a deviation of a relative positional relationship between the slit and the line sensor can be corrected. According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a determining means for determining a relative positional relationship between the slit and the line sensor in accordance with an output of the line sensor, and the display means determines by the determining means. It is characterized by displaying result information.

According to a third aspect of the present invention, in the second aspect of the present invention, the adjusting means automatically adjusts a relative positional relationship between the slit and the line sensor in accordance with a result of the judgment by the judging means. . A fourth aspect of the present invention is characterized in that, in any one of the first to third aspects of the invention, the adjusting means adjusts the attitude of the image reading apparatus. According to a fifth aspect of the present invention, in the fourth aspect of the present invention, a foot is provided at a bottom portion of the image reading apparatus, and the height of the foot is adjusted by the adjusting means.

[0013]

FIG. 1 is a schematic view of a main part of an image reading apparatus according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes an original surface on the original placing portion 1a. Usually, a color image is placed on the original placing portion 1a and the color image is read. Reference numeral 2 denotes an illuminating means, which comprises, for example, a halogen lamp, a fluorescent lamp, or the like. Reference numeral 7 denotes a slit which has an opening which is long in a direction (main scanning direction) perpendicular to the paper surface, which is a direction in which pixels of a three-line sensor 6 serving as a light receiving unit described later are arranged. I have. The slit 7 has an opening shape so as to prevent a light beam from the document surface 1 in a region different from the target reading document surface 1 in the sub-scanning direction from entering the three-line sensor 6 surface as noise light. And the location is specified.

Reference numerals 3a, 3b, and 3c denote optical path bending mirrors, respectively, which guide a light beam reflected on the original surface 1 to an image forming lens 4 described later. The imaging lens 4 is a document (color image)
Is formed on the surface of the three-line sensor 6 via the color separation means 5.

The color separation means 5 is composed of a diffraction grating and separates the light beam from the imaging lens 4 into three primary colors of R (red), G (green) and B (blue). Reference numeral 6 denotes a light receiving means, which is a so-called monolithic three-line sensor in which three line sensors (CCD) 6a, 6b, and 6c are arranged on the same substrate surface so as to be parallel to the main scanning direction.

Reference numeral 8 denotes a sensor driver, 9 denotes an A / D converter, and 10 denotes a processing circuit which processes digital signals for each of the line sensors 6a, 6b and 6c converted by the A / D converter 9 and will be described later. It is input to the display unit 11. The display unit 11 as a display means is composed of a liquid crystal display, and displays each of the line sensors 6a, 6b, 6c based on output information from the processing circuit 10.

That is, in the present embodiment, as described later, for example, ordinary white paper or the like having a uniform density is placed on the original surface 1, and
At this time, output signals from the respective line sensors 6a, 6b, 6c corresponding to the R, G, B color lights are processed by passing through the sensor driver 8, the A / D converter 9, and the processing circuit 10, and the output signals are output. To each line sensor 6a,
The output waveform is displayed on the display unit 11 for each of 6b and 6c.

From the shape of the output waveform at this time, the assembling accuracy of the entire apparatus, for example, an error in the relative positional relationship between the slit 7 and the three-line sensor 6, that is, the attitude of the entire apparatus when the apparatus is installed in the market. Checking the normality of the status.

That is, it is assumed that when the apparatus is installed at a place where the apparatus is used, the flatness of the installation place is good and the relative positional relationship between the slit 7 and the three-line sensor 6 has been correctly adjusted. In this case, for example, if a document surface having a uniform density is placed on the document surface 1, the light beam from the document surface 1 is transmitted through a three-line sensor 6
When an image is formed on the surface, the same line image is formed in the sub-scanning direction on each of the line sensors 6a, 6b, and 6c corresponding to each of R, G, and B.

Therefore, as the output signals from the line sensors 6a, 6b, 6c corresponding to R, G, B, ie, output waveforms, substantially the same waveforms in the main scanning direction are obtained as shown in FIG. According to this, a color image can be digitally read with high precision.

On the other hand, when the installation location is inclined and the flatness is poor and the relative positional relationship between the slit and the three-line sensor is shifted, as shown in FIGS. Three line sensors 6a and 6 corresponding to G and B
The output signals from b and 6c, that is, the output waveforms appear differently.

For example, when the apparatus is installed, if the front side and the back side of the apparatus are not balanced, FIG.
As shown in the figure, a part of the light beam of the G color light is incident on the line sensor surface corresponding to the B color light on the front side of the apparatus. , The output signal from the line sensor corresponding to the G color light rises above the reference output signal (output level for reading a color image), and conversely, falls below the reference output signal on the front side and appears as an uneven output waveform. .

If the left and right sides of the apparatus are not balanced when the apparatus is installed, vignetting occurs due to, for example, a slit, and the output from each line sensor on the left side of the apparatus as shown in FIG. 3B. The signal falls below the reference output signal and appears as an uneven output waveform.

That is, the waveform of the output signal from the three-line sensor differs depending on the installation conditions of the apparatus. For this reason, in this embodiment, the output signal from the three-line sensor is displayed on the display unit, and the output signal is adjusted by using the signal displayed on the display unit, thereby adjusting the position of the slit or the three-line sensor. Adjusting relationship. In this way, each element is properly adjusted, and a color image is read with high accuracy.

As described above, in this embodiment, R, G, B
The normality of the relative positional relationship between the slit 7 and the three-line sensor 6 is confirmed by displaying an output waveform, which is an output signal from each of the line sensors 6a, 6b, and 6c, on the display unit 11. . If an abnormality is found in the output waveform displayed on the display unit 11, the relative position shift between the slit 7 and the three-line sensor 6 is adjusted by the attitude adjustment means described later while observing the output waveform. ing.

One of the means for adjusting the posture in the present embodiment utilizes a plurality of feet for supporting the apparatus (a portion corresponding to a surface on which the apparatus is installed), and the height of the feet can be freely changed. Then, the posture of the device is adjusted by appropriately adjusting the height of the foot, whereby the slits 7 and 3 are adjusted.
The relative positional deviation from the line sensor 6 is corrected.

As described above, in this embodiment, even if the relative positional deviation between the slit and the three-line sensor is caused by the installation location of the apparatus, the relative positional deviation can be easily readjusted by using the above-described method. As a result, a color image can be digitally read with high precision at any installation location.

In this embodiment, ordinary white paper is used as the above-mentioned original having a uniform density. However, any original having a uniform density may be used.

In this embodiment, a liquid crystal display is used as the display unit, but the present invention is not limited to this, and another display device may be used.

Next, as a second embodiment of the present invention, a method of collecting output signals from a three-line sensor as light receiving means will be described.

Generally, in a display unit such as a liquid crystal display, the number of pixels in the vertical (V) and horizontal (H) directions of the display unit is designed to be considerably smaller than the number of pixels of the line sensor. Therefore, there is a limit to displaying output signals from, for example, thousands of pixels forming the line sensor on the display unit as they are.

In general, even if an arbitrary number is selected from thousands of pixels forming a line sensor and an output signal is obtained, the output waveform from each line sensor displayed on the display section is normal or abnormal. This is not a big problem in determining whether there is.

Therefore, in the present embodiment, when the output signals from the line sensors corresponding to the R, G, and B color lights, that is, the output waveforms are displayed on the display unit, the number of output signals obtained from the line sensors is arbitrary. Is displayed.

That is, in the present embodiment, for example, 5 or 10 out of thousands of pixels forming the line sensor are used.
An arbitrary number is selected for each individual interval, and an output signal from the pixel is processed by a processing circuit and displayed on a display unit.

The relative positional relationship between the slit and the three-line sensor is adjusted by the above-described attitude adjusting means while observing the output signal from the three-line sensor, that is, the output waveform displayed on the display unit.

Next, as a third embodiment of the present invention, a method of displaying a display unit as a display means will be described.

In each of the above embodiments, the output waveform from the three-line sensor is directly displayed on the display unit, and the normality of the output waveform is independently determined by the operator (operator), and the slit and the three-line sensor are used. Is adjusted by the above-described posture adjusting means.

In this embodiment, a judging means for judging the normality of the output waveform from the three-line sensor is provided in the apparatus, and the content of the processing result from the judging means is displayed on the display unit as message information (judgment result information). it's shown.

For example, by displaying message information such as "the posture state is normal" or "the posture state is abnormal, please adjust the height of the feet", the operator can respond to the message information by displaying the entire system. Can be adjusted.

Next, as a fourth embodiment of the present invention, a method for automatically controlling the attitude adjusting means will be described.

In the third embodiment, message information is displayed on the display unit on the basis of the judgment result obtained by the judging means, and the output information is used by the operator to manually use the posture adjusting means, for example, for a plurality of feet corresponding to the installation surface of the apparatus. Had adjusted the height.

In this embodiment, a drive mechanism using a motor or the like capable of automatically adjusting the height of the foot is incorporated in the foot, and the information signal obtained by the judging means is used, for example. In the case of an abnormality, a motor or the like is automatically driven to adjust the height of the foot. Thereby, the relative positional deviation between the slit and the three-line sensor is corrected.

Next, another means different from the attitude adjusting method for adjusting the height of the apparatus as described above as the fifth embodiment of the present invention will be described.

In the first to fourth embodiments, in order to correct the flatness of the installation surface of the device as the posture adjusting means, the heights of the feet are appropriately adjusted by using a plurality of feet supporting the device. This corrects the relative positional deviation between the slit and the three-line sensor.

In this embodiment, in addition to the above-described adjustment method based on the height of the foot, for example, a method of adjusting the mounting position of the slit fixed directly in the apparatus by the driving means, or each of the components constituting the optical system Optical members (lenses, etc.)
The error generated from the attitude of the entire apparatus is corrected by a method of adjusting the height of the mounting position of the apparatus.

As described above, the same effect as in the above-described embodiment can be obtained by appropriately adjusting the mounting state of each optical member, for example, the height of the mounting position.

[0048]

According to the present invention, the relative positional deviation between the slit and the light receiving means, which is caused by the poor flatness of the installation place of the apparatus, can be easily adjusted, whereby the reading of the color image can be performed with high accuracy. An image reading apparatus that can perform the image reading can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of an image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a normal output waveform from a line sensor.

FIG. 3 is an explanatory diagram showing an abnormal output waveform from a line sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Original surface 2 Light source means 3a, 3b, 3c Optical path bending mirror 4 Imaging lens 5 Diffraction grating 6 Light receiving means (3 line sensor) 7 Slit 8 Sensor driver 9 A / D converter 10 Processing circuit 11 Display means (display section)

Claims (5)

(57) [Claims] 1. An image reading apparatus, comprising: a document placing portion; a slit for regulating reflected light from a document placed on the document placing portion; and a line sensor for receiving light passing through the slit. display means for displaying information about the relative positional relationship between the line sensor and the slit by using an output of the line sensor when reading a document of uniform density, the Sri
To adjust the relative position of the line sensor and the line sensor.
Knot means, and the slit and the line sensor
An image reading apparatus capable of correcting a relative positional deviation . 2. The switch according to claim 1, further comprising:
Judge the relative positional relationship between the lit and the line sensor.
Determining means, wherein the display means is based on the determining means.
2. The image reading apparatus according to claim 1, wherein the determination result information is displayed . 3. The result of the judgment by said judging means is determined by said adjusting means.
According to the relative position of the slit and the line sensor
3. The image of claim 2, wherein the relationship is adjusted automatically.
Image reading device. (4) The adjusting means adjusts the attitude of the image reading device.
The method according to any one of claims 1 to 3, wherein
The image reading device according to claim 1. (5) The image reading device has a foot on the bottom,
The height of the foot is adjusted by adjusting means.
The image reading device according to claim 4, wherein: