JP2007336208A - Image reading apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus and an image forming apparatus which can provide vivid image data where fluctuation caused by a noise component in the horizontal direction of an image which occurs during scanning is eliminated. <P>SOLUTION: The image reading apparatus reads an image in the horizontal direction and the vertical direction and captures an area-shaped image or reads the image in the horizontal direction by a plurality of pixels and reads the image in the vertical direction while directly or optically moving pixels to thereby capture the area-shaped image, wherein a plurality of pieces of data read in the vertical direction are averaged. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image reading apparatus and an image forming apparatus.

  In an image reading apparatus in which the reading period (T2) in the vertical direction is significantly different from the reading time (T1) for one line in the horizontal direction, a noise component in the horizontal direction tends to appear in the read image. The noise component referred to here is noise generated from poor S / N of the image signal or noise generated by vibration. 1 to 6, the horizontal direction (main scanning direction) is read by a plurality of pixels, and the vertical direction (sub-scanning direction) is read while moving the pixels directly or optically, thereby forming an area shape. The image obtained by the image reading apparatus that captures the image is taken as an image. The numbers in the figure represent the amount of light that enters each area.

  When there is one image (FIG. 1) extending in the vertical direction, if there is no noise component, there are five capture timings in one pixel in the vertical direction as an example. Even when data is used once, it appears as a straight line image as shown in FIG. However, when scanning, there may be a case where a horizontal component appears in the horizontal direction due to the influence of vibration or electrical noise. At this time, the scanning period (T2) in the vertical direction is significantly different from the scanning time (T1) for one horizontal line (in the example of FIG. 3, there are five capture timings in one vertical pixel). In the case of using one out of five data for image formation), a noise component is placed on the captured image as shown in FIG. 4, and the image is recognized as an image different from the original image.

  As a conventional technique, Patent Document 1 discloses a fluctuation correction unit in the main scanning direction due to camera shake of a manual image scanner apparatus. In this example, there is an example in which a detection means for detecting the amount of fluctuation in the main scanning direction is provided in the image scanner apparatus and the detected amount is used for correction. However, the signal is included in the signal due to poor S / N. The noise component cannot be detected and cannot be corrected. Further, as another conventional technique, Patent Document 2 discloses a technique for performing an appropriate black level correction process and reducing a horizontal stripe without being affected by a noise component as much as possible.

Also, there is a technology that removes noise components by capturing the data multiple times and averaging it with a device that captures images at once like a digital camera, but this technology captures the data multiple times. Since it is necessary to capture, there is a time loss for the number of times data is captured.
JP-A-7-303176 JP 2006-025286 A

  The present invention has been made in view of the above circumstances, and provides an image reading apparatus and an image forming apparatus that can obtain an image close to the original data and that it does not take time to remove noise components. The purpose is to do.

  In order to achieve this object, the invention according to claim 1 is an image reading apparatus that reads an image in a horizontal direction and a vertical direction and takes an image of an area shape, and averages a plurality of data read in the vertical direction. It is characterized by doing.

  According to a second aspect of the present invention, in the image reading apparatus for reading an area-shaped image, the horizontal direction is read by a plurality of pixels, and the vertical direction is read while moving the pixels directly or optically. A plurality of data read in the vertical direction are averaged.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the number of data to be averaged is changed.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, characterized in that the length averaged in the vertical direction is the same as the reading length of one pixel in the horizontal direction. .

  The invention described in claim 5 is characterized in that in the invention described in any one of claims 1 to 4, it has a switching function for switching between a case where a plurality of data are averaged and a case where they are not averaged.

  According to a sixth aspect of the present invention, there is provided the image reading device means according to any one of the first to fifth aspects.

  The invention according to claim 7 reads the data having no fluctuation as a reference for the fluctuation evaluation, determines the fluctuation amount, analyzes the fluctuation amount, calculates an appropriate reading speed and the average number of times, and reads the reading speed and the average The number of times is set.

  The invention described in claim 8 is characterized in that, in the invention described in claim 7, there is provided data for evaluating lateral fluctuation and means for printing the data.

  According to the present invention, it is possible to obtain clear image data in which a fluctuation due to a noise component in a horizontal direction of an image that occurs during scanning is eliminated.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

The configuration of an image reading apparatus and an image forming apparatus according to an embodiment of the present invention is shown in FIG.
As shown in FIG. 10, the image forming apparatus 1 of this embodiment includes an apparatus main body 2, an automatic document feeder 3, an image reading unit 4, a paper feeding unit 5, and a writing unit 6. .

  The apparatus main body 2 is formed in a box shape, for example, and is installed on a floor or the like. The apparatus main body 2 accommodates an image reading unit 4, a paper feeding unit 5, and a writing unit 6.

  The automatic document feeder 3 is attached to the upper part of the apparatus body 2. The automatic document feeder 3 includes a document placing plate 7 and a belt feeder 8. The document placing plate 7 is formed in a flat plate shape, is attached to the upper part of the apparatus main body 2, and a plurality of documents 9 are placed on the surface. The belt feeding device 8 feeds the documents 9 on the document placing plate 7 one by one onto a contact glass 10 which will be described later, and the document 9 on which a reflected image is read by a lens block 16 which will be described later is sent from the contact glass 10 Drain out of the main body 2.

  The image reading unit 4 is provided above the apparatus main body 2 and below the automatic document feeder 3 described above, and includes a contact glass 10 on which an original is placed and an optical scanning system 11. The contact glass 10 is attached to the upper surface of the apparatus main body 2 with both surfaces parallel to the horizontal direction. The optical scanning system 11 includes an exposure lamp 12, a first mirror 13, a second mirror 14, a third mirror 15, a lens block 16, and the like.

  The exposure lamp 12 irradiates the document 9 on the contact glass 10 with light. The first mirror 13, the second mirror 14, and the third mirror 15 guide the reflected image from the document 9 to the lens block 16. The exposure lamp 12 and the first mirror 13 are fixed on a first carriage (not shown), and the second mirror 14 and the third mirror 15 are fixed on a second carriage (not shown). When reading a document, the first carriage and the second carriage are mechanically moved at a relative speed of 2: 1 so that the optical path length does not change. The aforementioned first carriage and second carriage of the optical scanning system 11 are moved by a scanner drive motor (not shown).

  The lens block 16 includes an imaging lens system 31, an image sensor 32, and the like. The lens block 16 reads the reflection image of the document described above by the image sensor 32, converts the optical signal into an electrical signal, and processes it. The converted electrical signal is output toward an image processing unit (not shown). When the imaging lens system 31 and the CCD image sensor 32 are moved in the left-right direction (horizontal direction) in FIG. 10, the image magnification can be changed. That is, the positions of the imaging lens system 31 and the CCD image sensor 32 in the left-right direction in FIG. 10 are set corresponding to the specified magnification.

  The paper feed unit 5 includes a plurality of transfer paper storage portions 19 provided at the lower part of the apparatus main body 2 and a transfer paper feed unit 20. The transfer paper storage unit 19 stores a plurality of transfer papers 21. The transfer paper feed unit 20 sends the transfer paper 21 in the transfer paper storage unit 19 between registration rollers 25 described later. The paper feeding unit 5 feeds the transfer paper 21 in the transfer paper storage unit 19 one by one toward the registration roller 25, that is, the writing unit 6.

  The writing unit 6 includes a laser output unit 22, an imaging lens 23, a mirror 24, a registration roller 25, a photosensitive drum 26, a developing device 27, a transfer member 28, and a fixing device 29. Yes.

  Inside the laser output unit 22, there is provided a polygon mirror that rotates at a high speed at a high speed by a laser diode as a laser light source and a motor. Laser light emitted from the laser output unit 22 is deflected by the polygon mirror that rotates at a constant speed, passes through the imaging lens 23, is folded back by the mirror 24, and is condensed on the outer peripheral surface of the photosensitive drum 26. Image. The deflected laser light is exposed and scanned in a so-called main scanning direction orthogonal to the direction in which the photosensitive drum 26 rotates, and recording is performed in line units of an image signal output from an image processing unit (not shown). Then, the writing unit 6 forms an image, that is, an electrostatic latent image, on the outer peripheral surface of the photosensitive drum 26 by repeating main scanning at a predetermined cycle corresponding to the rotational speed and recording density of the photosensitive drum 26. .

  In this way, the laser light output from the writing unit 6 is applied to the photosensitive drum 26 of the image forming system, and a main scanning synchronization signal is generated at the irradiation position of the laser light near one end of the photosensitive drum 26. A beam sensor (not shown) is arranged. Based on the main scanning synchronization signal output from the beam sensor, control of image recording timing in the main scanning direction and generation of a control signal for input / output of an image signal described later are performed.

  The registration roller 25 sends the transfer paper 21 sent from the transfer paper storage unit 19 by the transfer paper sending unit 20 between the transfer member 28 and the photosensitive drum 26. The photosensitive drum 26 is formed in a columnar shape or a cylindrical shape that is rotatable around an axis. The photosensitive drum 26 is developed by the toner attached to the electrostatic latent image formed and carried by the laser output unit 22, and the toner image thus obtained is transferred onto the transfer paper 21 positioned between the transfer member 28. Transcript.

  The developing device 27 causes toner to adhere to the outer peripheral surface of the photosensitive drum 26 and develops the electrostatic latent image on the outer peripheral surface of the photosensitive drum 26. The transfer member 28 presses the transfer paper 21 against the outer peripheral surface of the photosensitive drum 26 to transfer the toner on the outer peripheral surface of the photosensitive drum 26 to the transfer paper 21 and directs the transfer paper 21 toward the fixing device 29. Send it out. The fixing device 29 fixes the toner image formed on the photosensitive drum 26 and the like onto the transfer paper 21 and discharges the transfer paper 21 out of the apparatus main body 2.

  In the image forming apparatus 1 described above, the automatic document feeder 3 automatically feeds the document onto the contact glass 10 of the image reading unit 4 and automatically discharges the document after reading. In the image forming apparatus 1, the image reading unit 4 irradiates a document set on the contact glass 10 with light, and a reflected image from the document is read by a line type photoelectric conversion element 42 as a photoelectric conversion element described later.

  In the image forming apparatus 1, the writing unit 6 forms an image on the photosensitive drum 26 in accordance with the image signal of the read original, and transfers the image onto the transfer paper 21 fed from the paper feeding unit 5. And fix. The image forming apparatus 1 discharges the transfer paper 21 that has been fixed to the outside of the apparatus main body 2.

  Note that the image reading apparatus (image reading unit 4) and the image forming apparatus of the present embodiment shown in FIG. 10 have an arithmetic circuit and a control circuit (not shown), and execute the operations of the following examples by program control. .

  In Embodiment 1 of the present invention, in the image forming apparatus having the above-described configuration, horizontal and vertical images are read, an area-shaped image is captured, and a plurality of data read in the vertical direction is averaged.

  FIG. 5 shows an example in which data is read five times in the horizontal direction while the vertical direction advances by one pixel. At this time, when the data is averaged in the vertical direction, the result is as shown in FIG. 6 and becomes a straight line substantially similar to the original data in FIG.

  As described above, according to the present embodiment, when a plurality of pieces of data read in the vertical direction are averaged, the images swayed in the horizontal direction in the meantime can be averaged, and the data at the substantially center position of the horizontal fluctuation is extracted. I can do it. As a result, clear image data can be obtained in which fluctuations caused by noise components in the horizontal direction of the image that occur during scanning are eliminated.

  In the first embodiment of the present invention, in the image reading apparatus and the image forming apparatus having the above-described configuration, the horizontal direction reads by a plurality of pixels, and the vertical direction moves the pixels directly or optically. By reading the image, the area-shaped image is captured, and a plurality of data read in the vertical direction are averaged.

  As described above, according to the present embodiment, when a plurality of pieces of data read in the vertical direction are averaged, the images swayed in the horizontal direction in the meantime can be averaged, and the data at the substantially center position of the horizontal fluctuation is extracted. I can do it. As a result, a clear image can be obtained in which fluctuations due to noise components in the horizontal direction of the image occurring during scanning are eliminated.

  In the present embodiment, the average number of data is changed in the first embodiment. That is, in the first embodiment, the average number of times in the vertical direction is 5. However, by increasing this number, it is possible to cut a noise component having a lower frequency. However, if the average number is increased too much, the image reading resolution is lowered. Therefore, this number should be set appropriately according to the specifications of the image reading apparatus and the magnitude and frequency of noise.

  As described above, according to the present embodiment, the degree of rounding of data can be adjusted by changing the number of data to be averaged. As a result, the amount of erasure can be controlled and unnecessary image deterioration can be prevented. The rounded condition referred to here is how the image obtained as an image feels as a sense of the viewer. For image data such as photographs, it is easier to see images with smoother image changes by increasing the averaging to reduce noise, and for images with many characters and lines, the averaging is reduced and fine data changes can be seen. The image will be easier to see as the image. An apparatus capable of changing this condition is obtained.

  In this embodiment, in Embodiments 1 and 2, the average length in the vertical direction is the same as the reading length of one pixel in the horizontal direction. As shown in FIG. 5, the length averaged in the vertical direction is the same as the reading length of one pixel in the horizontal direction.

  As described above, according to the present embodiment, the calculated image data is image data having an aspect ratio of 1: 1, and the subsequent processing and handling such as writing are facilitated.

  In this embodiment, in the first to third embodiments, the averaging number can be changed by an arithmetic circuit in the image reading apparatus. The length averaged in the vertical direction can be set to be the same as the reading length of one pixel in the horizontal direction.

  Further, in the present embodiment, in the first to third embodiments, the averaging process has a switching function for the case of averaging and the case of not averaging. This switching function is provided in the image reading apparatus, and an input for the switching may be performed by a person or automatically performed according to the calculation result in the calculation circuit.

  As described above, when averaging is performed according to the present embodiment, noise can be eliminated as described above, and image data such as a photograph becomes an image with less noise, but an image with many characters and lines has its side effects. As a result, the data may be rounded. When noise can be eliminated by other methods, it is possible to see fine changes in data that cannot be seen by averaging by switching so as not to perform averaging.

  The present embodiment is an image forming apparatus having the functions of the first to fourth embodiments. This image forming apparatus is generally the same as the image forming apparatus shown in FIG. 10, but the part that performs image processing can perform the functions of the first to fourth embodiments.

  As described above, according to this embodiment, a high-quality image can be formed.

  The present embodiment is the same as the copying machine shown in FIG. 10, but the control circuit reads the data having no fluctuation as a reference for the fluctuation evaluation in the means for evaluating the horizontal fluctuation and compares it with the original data. Thus, by determining the amount of fluctuation that the reading means has, and analyzing the amount of fluctuation, an appropriate reading speed and average number of times are calculated, and this reading speed and average number of times are set.

Here, the procedure for evaluating the amount of looseness will be described.
A chart with a straight line extending in the vertical direction is prepared and placed on the reader. In this state, the chart is read, and the linear position of the read data is obtained for each position in the vertical direction. When the difference between the obtained straight line position and the original straight line position is obtained, the amount of fluctuation is obtained.

Here, a method for calculating (determining) the optimum reading speed and the average number of times will be described.
The apparatus prepares several patterns of the average number of times (for example, an average of 2 times, 3 times, and 5 times). Further, since simply increasing the average number of times will increase the reading time, it is necessary to increase the reading speed in the horizontal direction corresponding to the average number of times. Therefore, a plurality of patterns are prepared for the horizontal scanning speed. (Note that the horizontal scanning speed is related to the sensitivity of the CCD and cannot be increased indefinitely. However, if the horizontal scanning speed is changed, the gain is adjusted in the subsequent processing circuit. Also, it is necessary to adjust the light level of the light source to adjust to the appropriate signal level.) Also, read the chart written not only in the vertical direction but also in the diagonal direction and horizontal direction and check its reproducibility . If the number of averaging is increased too much, the reproducibility of the chart in the diagonal direction and the horizontal direction will deteriorate. Therefore, in consideration of the vertical amount of slack and the reproducibility of the diagonal chart, the average number of times and the reading speed are determined so that both can satisfy a predetermined standard.

  In the above, the horizontal scanning speed is changed according to the average number of times. However, the scanning speed is set to the highest speed from the beginning, and the interval between the horizontal scanning and the next horizontal scanning is used. Alternatively, the average number of times may be changed. With this method, since the amount of light entering the reading pixel does not change, light amount adjustment and gain adjustment of the light source are unnecessary.

  As described above, according to the present embodiment, the data having no fluctuation as a reference for the fluctuation evaluation in the means for evaluating the horizontal fluctuation is read, and compared with the original data, the amount of fluctuation that the reading means has can be obtained. Can be judged. By analyzing this amount and calculating and setting an appropriate reading speed and average number of times, a clear image can be obtained in which fluctuation due to noise components has been eliminated.

  The present embodiment is the same as the copying machine shown in FIG. 10, but the control circuit has data for evaluating lateral fluctuation (when printed, it becomes an evaluation chart). This printed chart is a chart in which vertical lines are written, but may be one using diagonal lines, horizontal lines, or block-shaped pictures as long as it can cover the reading range for averaging in the vertical direction. . The image forming apparatus also has means (printing means) for writing out the data.

  As described above, according to this embodiment, even if the evaluation unit is not prepared in advance, it is possible to make the device to be adjusted to make the evaluation unit and to improve the operability.

  In the above description, the data is averaged, but a weighted filter may be applied. In the case of the data in Table 7, if the weighting in Table 8 is performed, the data in Table 9 is obtained. The calculation for weighting is (data 1 × 1 + data 2 × 2 + data 3 × 3 + data 4 × 2 + data 5 × 1) ÷ 9 = 1 pixel data.

  The data of FIG. 9 obtained at this time is less noise components than averaging, but is more suitable than averaging if data that emphasizes data for each pixel pitch in the sub-scanning direction is desired.

  Further, each of the above embodiments is not limited to the image reading apparatus using the reduction optical system as shown in FIG. 10, but is an image capturing apparatus using an equal magnification sensor (CIS) or the like, or a sheet through type The present invention is also applied to the image capturing device.

  An example using CIS is shown in FIG. The content is obtained by replacing the image reading unit 4 of the copying machine shown in FIG. 10 with a CIS.

  As another embodiment, an example in which a plurality of reading pixels are used has been described. However, the horizontal direction is a single reading pixel, which is optically moved by moving the pixel directly or by scanning the vibration movement of the mirror. Image reading apparatus that reads an image while moving the image and moves the reading pixel directly in the vertical direction, or reads the image while moving optically by scanning a mirror, etc. (Example 1 (example using a single reading pixel)).

  In the above description, the data captured at the time of averaging is simply averaged. However, the data may be weighted while averaging. As a result, the effect of noise component removal is different from that in the case of no weighting, and the weighting coefficient may be changed as appropriate while viewing the image.

  As mentioned above, although each Example of this invention was described, it is not limited to said each Example, A various deformation | transformation is possible in the range which does not deviate from the summary.

  The present invention can be applied to a scan-type image reading apparatus (digital camera, X-ray photography apparatus, etc.).

It is a figure which shows an example of the image of the image obtained with the image reader. It is a figure which shows an example of the image of the image obtained with the image reader. It is a figure which shows an example of the image of the image obtained with the image reader. It is a figure which shows an example of the image of the image obtained with the image reader. It is a figure which shows an example of the image of the image obtained with the image reader. It is a figure which shows an example of the image of the image obtained with the image reader. It is a figure which shows an example of the image of the image obtained with the image reader. It is a figure which shows an example of the image of the image obtained with the image reader. It is a figure which shows an example of the image of the image obtained with the image reader. 1 is a side view illustrating a schematic configuration of an image reading apparatus and an image forming apparatus according to an embodiment of the present invention. 1 is a side view illustrating a schematic configuration of an image reading apparatus and an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Apparatus main body 3 Automatic document feeder 4 Image reading unit 5 Paper feed unit 6 Writing unit 7 Document placing plate 8 Belt feeder 9 Document 10 Contact glass 11 Optical scanning system 12 Exposure lamp 13 First mirror 14 Second mirror 15 Third mirror 16 Lens block 19 Transfer paper storage unit 20 Transfer paper feeding unit 21 Transfer paper 22 Laser output unit 23 Imaging lens 24 Mirror 25 Registration roller 26 Photosensitive drum 27 Developing device 28 Transfer member 29 Fixing device 31 Imaging lens system 32 Image sensor 40 CIS
41 Light source 42 Rod lens array 43 Image sensor

Claims (8)

In the image reading apparatus that reads the image in the horizontal direction and the vertical direction and captures the image of the area shape,
An image reading apparatus that averages a plurality of data read in the vertical direction. In an image reading apparatus that captures an area-shaped image by performing reading with a plurality of pixels in the horizontal direction and performing reading while moving the pixels directly or optically in the vertical direction.
An image reading apparatus that averages a plurality of data read in the vertical direction.   3. The image reading apparatus according to claim 1, wherein the number of data to be averaged is changed.   4. The image reading apparatus according to claim 1, wherein an average length in the vertical direction is the same as a reading length of one pixel in the horizontal direction. 5.   5. The image reading apparatus according to claim 1, further comprising a switching function that switches between averaging and non-averaging of the plurality of data.   An image forming apparatus comprising the image reading device unit according to claim 1.   Reads the data without the standard for the evaluation of fluctuation, determines the amount of fluctuation, analyzes the amount of fluctuation, calculates the appropriate reading speed and the average number of times, and sets the reading speed and the average number of times An image forming apparatus.   8. The image forming apparatus according to claim 7, further comprising: data for evaluating the horizontal fluctuation and means for printing the data.

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