JP2002290685A - Image scanner and method of correcting input element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading unit which is capable of improving the images of both the front and rear of a manuscript in quality and uniformity by improving an input element located on is rear side in correction accuracy. SOLUTION: The image scanner reads image information on both the front and rear of a manuscript through a single run of the manuscript, a scanning means 8 of an optical system of one magnification is secured to an image scanner main body (an upper part of the scanner 2), a reference color member 254 used for correcting the input element 11 of a scanning means 8 is provided just under the running position of the manuscript, and the reference color plane of the reference color member 254 is so set as to be relatively movable to the input element 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction in which an original, which is an input image, is successively moved along a fixed optical path, and the original is read, processed (variable correction for density adjustment, etc.) and then printed or transmitted. For example, the present invention relates to an image forming apparatus such as a digital copying machine, a facsimile apparatus, and a scanner apparatus, and more particularly, to a DSPF that reads both sides of a document in one run.
The present invention relates to an image reading device and a method for correcting an input element in a (double-sided automatic document feeder).

[0002]

2. Description of the Related Art In an image forming process in a digital copying machine, a facsimile machine and a scanner, a document is mounted on a document table or a document feeder, and the document is illuminated by a light source. It is input (read) to an optical reading element (input element).

[0003] Image information of a document is usually taken line by line. When the document is placed on a fixed platen, the light path between the light source, the document and the element is sequentially moved. When a document is moved by an apparatus or the like, the document is read by moving the document while fixing an optical path between the light source, the document, and the element.

That is, the image information in the main scanning direction (line direction of the document) depends on the number of input elements, and the number of lines in the sub-scanning direction (direction perpendicular to the main scanning direction) depends on the reading timing of the elements and the light source (light source). Or document feed).

When reading the back side of an original, after the original is run, the original is turned upside down and placed on the original platen again (RADF) or run (RSPF), and the same operation as the front side is performed again. To read the back side to obtain image information on both sides.

However, in such double-sided reading, since the original is turned upside down during the process of reading the original twice, the original is placed (or run) twice in the reading device.
As a result, the reading time (times) is longer than that of reading only one side. Further, since the reversing mechanism is complicated, there is a problem that the device is bulky and the cost is high.

In order to solve such a problem, there is a device (DSPF) which can read image information on both front and back surfaces while a document is run once. This device is
The contact optical sensor is disposed so as to correspond to the back side of the document fed and moved by the document feeder (the front side is read by the same reading operation as in the related art).

This method is realized by adding a mechanism for reading the back side to the conventional document feeder, so that a mechanism for turning over the document is not required. Further, since the information on both the front and back sides can be read by one document feeding movement, both-side reading can be performed at the same speed as that for single-side reading.

[0009]

Normally, when the original is reversed and the front and back sides are read by the same reading device, there is no difference in image quality. However, as described above, when reading information on the front and back sides simultaneously by one document feeding movement, the reading devices are different between the front side and the back side, so that there is no difference in image quality between the front and back sides. The characteristics of the device must be well adjusted.

In addition, it is necessary to appropriately correct the input element of each reading device. In the case of a device using a conventional reduction optical system, a white plate for referencing and adjusting a reference of a white level is provided.
It is often attached to a contact glass on which a document is placed. In this case, an optical path between the white plate and the input element is in a closed space.

Therefore, since there is no fear that dirt or dust adheres to the white plate, adjustment for each reading element is performed at an appropriate timing when the power is turned on. Since the reference sub-scanning position can be changed, and the adjustment is usually performed based on the information of several lines, more stable adjustment can be performed.

On the other hand, the input element on the back side of the 1 × optical system is
The white plate to which the white level is to be adjusted is provided below the reading position (the position where the document passes) in a fixed state (to allow the document to pass), and the white plate reading position (white reference position) Is always the same.

For this reason, the optical path is always exposed to the outside, and when stains or the like are locally generated, when the correction between the reading elements is performed similarly to the surface, an image is formed on the stained portion. Since correction is made to make the image brighter, an image having white streaks is obtained as a reading result.

On the other hand, the input element on the back side of the 1 × optical system is
The white plate to be adjusted with reference to the white level is provided below the reading position (the position where the document passes) in a fixed state (to allow the document to pass), exposed to the outside, and the position where the white plate is read. (White reference position) is always the same.

Therefore, even if the input characteristics of the front and back surfaces are initially equivalent, input can be stably performed on the front surface every time with respect to a change such as aging, whereas the back surface is particularly suitable for the element. For each correction, since the initial data is continuously used (for example, there is a concern that a foreign substance may adhere to the white plate), the input state may be different from the front side.

At present, in image formation such as copier and facsimile, features of the input image are extracted from the input image.
An output image is formed by performing processing (correction) according to the feature (area separation processing). However, if the correction for each input element is not performed properly, it will affect the performance of the subsequent stage feature extraction, causing a difference between the front and back output images, making it impossible to homogenize the image quality.

The present invention has been made in view of such circumstances, and in particular, by improving the correction accuracy of the input element on the back side,
It is an object of the present invention to provide an image reading apparatus that improves and homogenizes the image quality of both sides of a document and a method of correcting an input element with stable accuracy.

[0018]

According to the present invention, means for solving the above-mentioned problems are constituted as follows.

(1) Image information of a document is read, processed to form an output image, and is provided in an image forming apparatus which prints or transmits the image. In an image reading apparatus for reading an image, a reading means of an equal-magnification optical system for reading image information on the back side of a running document is fixed to a reading apparatus main body, and an input element of the reading means is corrected. A reference color member is provided immediately below the document traveling position, so that a reference color surface of the reference color member is relatively movable with respect to the input element.

According to this configuration, the contaminated portion can be removed from the reading line by appropriately moving the reference color plane to be referred to with respect to the fixed reading means. Therefore, the correction accuracy can be remarkably improved as compared with the case of reading the same line of a fixed white plate (there is a high possibility that a portion contaminated by the attachment of dust or the like exists) as in the related art.

(2) The reference color member is a rotating body.

According to this configuration, by rotating and using the reference color member, a contaminated portion can be avoided and a portion that has not been exposed to the outside can be used as a reference portion.
It is possible to reduce the influence of foreign substances such as dirt and dust.

(3) The reference color member is a polygonal rotating polyhedron.

According to this configuration, the reference color surface having a certain area can be opposed (referenced) to the input element. For this reason, the setting of the corresponding positional relationship between the input element and the reference color member does not require a high degree of accuracy, so that the device can be manufactured relatively easily and the manufacturing cost can be reduced.

(4) The reference color member is a rollable belt-like body.

According to this configuration, the reference color surface that can be moved with a certain area is opposed to the input element (see).
Can be done. For this reason, the setting of the corresponding positional relationship between the input element and the reference color member does not require a high degree of accuracy, so that the device can be manufactured relatively easily and the manufacturing cost can be reduced.

(5) The reference color member is a take-up roll.

According to this configuration, the reference color plane that can be moved with a certain area is opposed to the input element (see).
Can be done. For this reason, the setting of the corresponding positional relationship between the input element and the reference color member does not require a high degree of accuracy, so that the device can be manufactured relatively easily and the manufacturing cost can be reduced.

(6) A cleaning member for cleaning the reference color member is provided in the reading device main body.

According to this configuration, since the reference color surface can be cleaned by the cleaning member, highly reliable correction can be realized.

(7) The reference color member has a plurality of reference color planes having different gradations.

Conventionally, correction of only white color is performed. However, according to this configuration, the intermediate density and black are checked and image processing is performed. Standard image quality can be obtained.

(8) The reference color member of the reference color member has a plurality of reflectances.

According to this configuration, when the relationship between the reflectance and the brightness is fluctuating, it is monitored, the fluctuation of the light amount of the light source of the apparatus and the fluctuation of the element sensitivity are detected, and the adjustment and input of the input apparatus are performed. By using it for image processing, a certain level of image quality can always be obtained.

(9) The invention is characterized in that the reference color surface of the reference color member facing the input element can be switched and used at the time of adjustment and at the time of document traveling.

According to this structure, the reference is corrected with an appropriate gradation or reflectance at the time of reference, and at the time of reading a document, the reference color plane having the gradation and reflectance so that the document is not affected by the reflected light. Is opposed to the input element, stable image quality can be ensured even for a thin original or a transparent original (OHP sheet).

(10) The portion of the reference color member facing the input element when the original is running has a surface characteristic suitable for running the original.

According to this configuration, an appropriate correction is made at the time of reference, and at the time of reading the original, a portion having a surface characteristic, for example, which makes the surface particularly smooth, is opposed so that the original runs smoothly. Thus, the original can be properly run, and the stability of the image quality can be improved.

(11) An opening is formed in the portion of the reference color member facing the input element when the original travels, so that an auxiliary member for smoothing the original traveling corresponds to the original travel path. Features.

According to this configuration, appropriate correction is performed at the time of reference, and at the time of reading a document, a portion whose surface shape has been changed is particularly opposed so that the document runs smoothly, thereby contributing to proper running of the document. I do.

(12) The portion of the reference color member facing the input element when the original is running has an original feeding function.

According to this configuration, by using the reference color member for driving the original, the corresponding positional relationship between the input element and the original can be more stably secured, and the thickness and warpage of the original can be secured. Since the influence can be reduced, the image quality can be stabilized regardless of the type of the original.

(13) The reference color member also serves as a reference when reading the front side.

According to this configuration, a reference color member for surface input is not required. In addition, since the front surface and the back surface can be adjusted based on the same reference, subsequent processes can be shared.

(14) The correction of the input element by the reference color member provided in the image reading apparatus according to any one of the first to thirteenth aspects is performed at a fixed timing such as when power is turned on.

According to this configuration, by performing the correction at a constant timing, the correction can be performed with higher reliability, and the image quality can be stabilized.

(15) The reference color surface of the reference color member provided in the image reading device according to any one of claims 1 to 13 is moved relatively to the input element, and the reference color information is obtained at different portions. It is characterized in that the input element is corrected a plurality of times and is corrected based on the data.

According to this configuration, since a plurality of lines of different parts are input, the part where the abnormality has occurred is specified,
Processing can be performed excluding the data, and the correction accuracy can be stabilized and improved.

(16) The correction of the input element is performed at a fixed timing such as when power is turned on.

According to this configuration, since the correction is performed at a constant timing, the correction accuracy can be further improved, and the image quality can be stabilized.

[0051]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image reading apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration of a reading apparatus having a scanner function of a conventional general digital multifunction peripheral.
This scanner device is used for applications such as copier / FAX / network scanners, and the main body of the reading device includes a scanner base 1 and a scanner upper part 2.

The scanner base 1 has a function of reading image information of a document placed on a document table 3 made of contact glass, and a function of reading image information of a document running while fixing the reading position. A lamp unit 4 having a lamp 4a and a reflecting mirror 4b capable of sufficiently exposing the main scanning length of the document table 3; and a CCD that reflects light incident on the document by light emitted from the lamp 4a.
And a mirror group 5 that forms an image on a read element array (input element) 6 composed of.

The optical path length between the lamp 4a, the original, the mirror group 5, and the reading element array 6 is configured to always maintain a constant value irrespective of the scanning position. It has a sufficient number of elements to read the number of pixels for one line, and is arranged in the main scanning direction.

The lamp unit 4 moves in the sub-scanning direction orthogonal to the main scanning direction with respect to the document surface, and the information scanned by the main scanning line is sequentially imaged on the reading element array 6, and the reading element array 6 is read. Outputs this as pixel information of each line (for example, an image forming unit not shown). Thereby, the pixel information of the main scanning and the sub-scanning is input, and the original is read.

Further, the lamp unit 4 is held in a fixed state at a part of the document table 3 or at a dedicated reading position, and the document fed (moved) by the scanner upper part 2 is moved.
By irradiating with the lamp 4a, the line information can be read at appropriate line update timing.

On the other hand, the scanner upper section 2 is provided with a mechanism for feeding and moving the original, and moves the original so that the scanner base 1 is moved.
, And also functions as a document holder when reading on the document table 3, and is configured like a lid with respect to the scanner base 1. Below, the upper part of the scanner 2
Will be described.

The scanner upper section 2 is provided with a document travel path 7 for feeding and moving the document in the direction of the arrow, and for reading by the scanner base 1, reading the back side (upper side in the figure) of the running document. On the downstream side of the original travel path 7, a contact image sensor 8 serving as a reading unit is provided in the main scanning direction.

The close contact type image sensor 8 constitutes an equal-magnification optical system, is disposed at a position close to the downstream side of the document traveling path 7, and irradiates the document with a light source (for example, a plurality of LEDs, hereinafter referred to as LED). 9) and a self-occurring lens array 10 provided on the optical path of the reflected light from the original.
And the number of elements that satisfy the main scanning length and resolution of the original,
An input element (read element array) 11 for reading pixel information formed by the self-occ lens array 10 and a dustproof glass 12 are provided, and these are integrated as a CIS unit (contact type image sensor) 8.

With this configuration, as the document (for one line in the main scan) travels, the contact-type image sensor 8 reads line information on the back side at appropriate timing for line update, and the scanner base 1 Along with the reading operation on the front side (lower side), the image on the back side (upper side) of the document can be read, whereby the front and back sides of the document can be read together with the scanner base 1. The reading on the front side by the scanner base 1 is performed by moving the lamp unit 4 to a reading position (not shown) slightly to the left of FIG.

With the above arrangement, when reading only one side of the original, the reduction optical system of the scanner base 1 is used. When reading both sides, the close contact type image sensor 8 of the same magnification optical system is used. Used for That is, the scanner base 1 is used for the front side of one side and both sides, the scanner upper part 2 is used for the back side of the both sides reading, the original table 3 and the front side of the traveling original are read by the scanner base 1, and the back side of the traveling original is read. Is read by the upper part 2 of the scanner.

It should be noted that reading by the contact type image sensor 8 on the scanner upper part 2 is always used and the scanner base 1 is used.
Although it is possible to set to use for reading both sides only, the above-described setting is performed in each embodiment of the present invention described later.

The number of input elements for both the scanner base 1 and the scanner upper part 2 is determined by the maximum original main scanning width and the resolution in the apparatus, but the number is several thousands of pixels, and the apparatus is constructed with sufficiently aligned element characteristics. In this case, a correction mechanism is provided in order to sufficiently adjust the element characteristics and input the data so that the input can be stabilized.

In reading by the scanner base 1, there is a variation in the amount of light in the main scanning direction of the lamp 4 a, which is a single tube. Since variations occur, corrections for stabilizing input conditions including these are actually performed.

The gist of the present invention is to make such a correction, and a method of the correction will be described below.

The input elements (reading element rows 6 and 11) of the scanner base 1 and the scanner upper section 2 are both analog devices that input the reflected light of the original and output a voltage according to the amount of light, and are proportional to the amount of light. The output voltage is output. Therefore, the output voltage can be A / D converted to output a black to white density value.

By the way, for example, when the range of the output density value is smaller than the fluctuation range of the amount of light input to the input element,
All portions brighter than a certain amount of light (light portions of the document) have the brightest density values, and portions darker than a certain amount of light (dark portions of the document) all have the darkest density values. That is, in such a case, an output having insufficient gradation is obtained. Therefore, it is necessary to adjust (correct) the relationship between the magnitude of the amount of light (reflected light from the document) input to the input element and the output density value.

When the range of the output density value is larger than the fluctuation of the amount of light input to the input element, the density of the original is included in a part of the output density value, and the density of the lighter (darker) is further reduced. Is not used, and the output is not accompanied by a smooth gradation change. Therefore, in order to prevent the occurrence of such inconveniences and to secure the desired performance, the output of the input element and the density value are appropriately adjusted.

The basic operation is as follows. A white reference plate (the conventional white reference plates 15 and 16 attached to the upper and lower surfaces of the document table 3 in FIG. 1) is read, and a predetermined target value is set, for example. In a system in which the output density digital value is set to 0 to 255, the output density digital value is set to 24.
The gain of the element sensitivity is adjusted to match 0 or the like. Normal,
Since the gains of the input elements cannot be individually adjusted, the gains of the input elements are adjusted for the entire element row (2Ch control or the like of the even-odd element row may be performed depending on the system). Note that the white reference plates 15 and 16 in FIG. 1 show a conventional example for explaining a general principle of correction.

Further, since the output of each element does not become the same value, it is managed by the average of the output of the element in a certain range, and the target value +
The actual operation takes into account the adjustment accuracy, the required time, the effect on the image quality, and the like.

The target value is set to the maximum value of the density value (255).
The reason is that, for example, when the density value 255 is output at the light amount A, the output is 255 even at the light amount 2A. Since the correction for lowering the gain cannot be performed for a bright light amount, such a gain correction of the element array is performed.

Further, the black reference is read with the black reference plate or the lamp turned off (there is an output even when the element is not exposed), and a preset target value, for example, an output density digital value is 0 to 255. Adjustment is performed while switching the offset of the element output so as to match the case of the system having the above. Normally, the offsets of the elements cannot be adjusted individually, so that the offset is adjusted for the entire element row.

Then, by optimizing the magnitude of the input light amount and the output density range, individual variations among the elements are corrected. Specifically, the density value (output of each element) of the white reference plate for one main scanning line (of the maximum document width of the apparatus) + the number of pixels of α (at the actual input resolution) is recorded.

At the time of this input, one line of data is taken, or a plurality of lines are inputted (the reading position is moved (only in the case of the scanner base 1)) to obtain an average value or abnormal data. And take other measures. As described above, the output of each element with respect to the white reference is recorded.

This output fluctuation is due to fluctuations in the amount of light illuminating the white reference plate and fluctuations in the characteristics of each element. At the same main scanning position, they correspond to the same portion of the light source and the same input element. There is no need for separation, as the relationship is maintained.

Now, based on the information on the output values of the respective elements, the output image is corrected in consideration of the characteristics of the input elements corresponding to one pixel in the main scanning, so that the corrected image is Variations in characteristics between the elements are absorbed. Such input element correction is called shading correction.
An example of the shading correction algorithm will be described below.

With reference to the white reference, the output values obtained from the respective input elements obtained as a result are A1 to Ax (x is the number of elements slightly more than one line in the main scanning), which is temporarily or permanently held. Is done. Hereinafter, the flow of correction will be described with the output value at a certain position as An.

An is, for example, when the output density digital value is 0 to
For a system with 255, the possible values are 0-255
Becomes Further, since the gain and offset of the entire input element have been adjusted before the shading correction, if the white reference and the light source and the element at the main scanning position have average characteristics (with respect to the average of the element array). It becomes a value near the target value.

If the value of An is larger than the target value,
It can be said that it has a characteristic of being input brighter than the average, and has a characteristic of being input darker if it is smaller. Note that this excludes cases where an abnormality described below has occurred.

At this time, if the image is brighter than the average, an average input image can be obtained by performing a process of making the input image darker. Further, when the input image is darker than the average, an average input image can be obtained by performing a process of making the input image brighter. These processes are performed by uniformly multiplying the image density value input according to An by the slope coefficient.

However, the white reference is sufficiently brighter than various originals,
If it is desired to make this brightness the maximum value of the density value, the average value / the target value is also multiplied by a coefficient. This is to sufficiently compensate the output range. For example, the target value is output value 240
In the case of this system, shading correction is performed by multiplying the input image by 255/240 to obtain an output value near 255 when an image is input with brightness about the white standard.

Therefore, the coefficient multiplied according to the value of An always includes a component for securing an output range of 255/240, and the multiplied coefficients are B0 to B255. This is a coefficient selected according to the density value obtained from An = 0 to 255, that is, the density value obtained from the white reference, and is set to Bm at a certain density m. For example, Bm = 255/240 × 24
0 / m. However, since the density is excessively corrected at a low density, the input image is actually multiplied by the coefficient Bm returned by referring to the table of B0 to B255 using the density m as a factor.

Therefore, the density of the image after shading correction at the n-th pixel in a certain main scanning position is: image density after shading = input image density × Bm (An) ← Bm is An
Thus, an image can be obtained in which the correction is made with the coefficients selected from the table, and the variation in the input characteristics in the main scanning direction is eliminated.

Although the shading correction operation has been outlined above, the correction in the scanner base 1 (hereinafter, shading correction), that is, the front side (lower side) of the original on the original platen 3 is described.
Between the elements for reading the original and reading the front side of the traveling original, and the correction in the scanner upper part 2 (hereinafter, shading correction), that is, the inter-element variation correction for reading the back side (upper side) of the traveling original. , There is a limitation on the current operation, especially for shading correction. In particular, the differences between and will be outlined below.

As described above, the positional relationship between the white reference plate and the input element in the conventional device is shown in FIG. In the conventional shading correction, the white reference plate 16 is provided outside the image input area of the document table 3 (the area deviating from the used portion when reading the document table), and the white reference plate 16 is read. At this time, the reading sub-scanning position can be set arbitrarily. For example, a plurality of lines of the white reference plate 16 can be read to obtain the above An. Thereby, local abnormalities (scratch,
Even if (dirt) occurs, shading correction can be performed with high accuracy so as not to be affected by the occurrence.

Further, since the optical path from the white reference plate 16 to the input element 6 is closed in the apparatus of the scanner base 1, the above-mentioned abnormality is unlikely to occur (that is, the stable input of the white reference is guaranteed twice). There). From this, normally, even when correction is frequently performed at the time of turning on the power, the white reference can be read sufficiently safely.

On the other hand, in the conventional shading correction, the white reference plate 15 disposed on the upper portion of the scanner base 1 (original platen 3) immediately below the input element but below the traveling position when the original is traveling is moved to the original. You will read through the platform 3. In addition, the position of the input element 11 for reading the traveling document is fixed. Therefore, only one line at the same position can always be referred to.

Thus, even if a correction algorithm in which the number of reference lines is increased, such as shading correction, is employed, the same line is actually read a plurality of times, and An can be obtained only from one line based on the substantially white reference. Can not.
Therefore, a local abnormality of the white reference plate 15 (the surface of the platen 3 or the like)
Is generated, the influence is considered (for example, it is determined that the output is abnormal with respect to the peripheral and overall input levels). It is necessary to carry a correction algorithm, but even if the abnormality can be detected, the LE of the main scanning position where the abnormality has occurred
The characteristics of the D array 9 and the input element 11) cannot be specified.

Further, the optical path from the white reference plate 15 to the input element 11 is not closed across the scanner base 1 and the scanner upper part 2 and penetrates the original travel path.
Abnormalities are more likely to occur than in shading correction.

From the above, it is assumed that there is no abnormality in the white reference plate 15 during the operation with respect to the shading correction. If the correction is performed frequently, the abnormality is reflected on the input of the image. The operation is extremely restricted as compared with the shading correction.

Therefore, for example, at the time of production and the white reference plate 15
When cleaning or replacing the input element 11 (white reference plate 15
Currently, it is necessary to confirm that the shading has been cleaned.

It is a feature of the present invention that the problem relating to the operation of the shading correction is eliminated and the operating conditions and reliability comparable to those of the shading correction are ensured. The embodiment will be described below.

(Embodiment 1) In this embodiment,
2, 14, 15, and 16. FIG. 2 shows the configuration of the reading device (note that the configuration other than the white reference plates 15 and 16 is the same as that of FIG. 1). In this case, a white roller member (rotary member) 151 is disposed as a reference color member below a document traveling position corresponding to a CIS unit (contact image sensor) 8 serving as a reading device. However,
The roller member 151 is rotatably supported in the scanner base 1, a part of the document table 3 is cut out, and the white peripheral surface of the roller member 151 is exposed from the notch 31 to form the roller member 151. It corresponds directly below.

With such a configuration, shading correction can be performed as follows. That is,
The LED array 9 of the CIS unit 8 emits light to irradiate the white peripheral surface of the roller member 151, and the reflected light is read by the reading element array (input element) 11. When reading of one line is completed, the roller member 151 is slightly rotated (moved) and stopped, and reading (input) of reflected light on the peripheral surface of a portion different from the previous time is performed.

By repeating such reading operation (input operation) several times, white reference data can be obtained from a plurality of different peripheral portions of the roller member 151. The upper portion of the peripheral surface of the roller member 151 is set below the document traveling position in order to allow the document to pass thereover.

By performing such a reading operation a plurality of times, the value of An can be obtained from the read data of a plurality of lines, and the reference color plane of the roller member 151 can be obtained by referring to the plurality of lines similarly to the shading correction. Shading correction can be performed without being affected by abnormalities (such as adhesion of dirt) of (white reference). Note that such shading correction is preferably performed under the same conditions. For example, the shading correction may be performed at the time of turning on the power or after a lapse of a predetermined time from the time of turning on the power (for example, after completion of warm-up). Also,
The gain correction of the entire reading element may be performed after the shading correction is performed in the same manner as in the conventional apparatus (claim 15).

Alternatively, an algorithm for detecting a local abnormality in the main scanning position is used together, the read data at the site where the abnormality occurs is discarded, and the roller member 151 is further removed.
By rotating and reading, abnormal data can be eliminated more effectively, and the reliability can be improved (claims 1 and 2).

As described above, a part of the peripheral surface of the roller member 151 is exposed to the outside. However, by rotating the roller member 151 to change the position of the peripheral surface to be exposed, the peripheral surface is exposed. It is possible to sufficiently eliminate the influence of abnormal data due to adhesion of dirt and the like. Therefore, as in the case of the shading correction, the white reference can be read sufficiently safely even if the shading correction is performed frequently every time when the power is turned on. T) The correction accuracy can be remarkably improved (claims 14 and 16).

(Embodiment 2) In this embodiment,
3 and 15. When the white reference roller member 151 as a reference color member is a regular cylinder, the rotation center of the roller member 151 needs to be accurately set at a set position in the exposure optical path as shown in FIG. If the rotation center shifts, the distance between the input element 11 and the white reference plane changes because the white reference plane is obliquely opposed to the incident axis, and the loss of the incident light amount (vignetting) occurs. ) Occurs. The distance relationship between the input element 11 and the white reference affects the input density, and a reading loss due to a change in the angle also causes an input density change.

Therefore, high accuracy is required for the set position of the roller member 151. That is, ideally, the white reference facing the input element 11 is a plane orthogonal to the reading surface, and means for realizing this is shown in FIG.
(B) and (c).

FIG. 4A shows a structure in which a rotating body 152 as a reference color member is formed in a polygonal prism. In this case, for example, each white reference plane is a regular octagonal prism, and each white reference plane corresponds to the input element 11 directly, and white reference data is obtained from the eight white reference planes by sequentially rotating the white reference plane by 45 degrees. Therefore, there is no difficulty that the incident light amount is lost as in the case of the cylindrical roller member 151 described above.
5).

FIG. 4B shows a CIS unit 8 using a rollable white belt-like member 153 as a reference color member.
, The white reference plane is a plane perpendicular to the exposure light path for reading. In this case, the white belt-like member 153 is
By rolling the white belt-like member 153 little by little by electric or manual operation, the different parts are made to correspond to predetermined positions corresponding to the exposure optical path to the input element 11 directly. , White reference data can be obtained from many white reference planes. Even in this case, there is no difficulty that involves the loss of the incident light amount as in the case of the cylindrical roller member 151 described above.

FIG. 4C shows a configuration in which a roll-shaped white member 154 of a type in which a reference color member is wound up is formed so as to be a plane immediately below the CIS unit 8 and orthogonal to the exposure optical path. In this case, by sequentially winding the roll-shaped white member 154 from one reel 18 to the other reel 18 via the guide rollers 19, 19, a large amount of white material is provided at a predetermined position corresponding to the exposure optical path. White reference data can be obtained from the reference surface.

In any of the above cases, since the white reference surface to be read is a flat surface, the setting of the corresponding position between the CIS unit 8 and the reference color member 15 does not require high precision, making it easy to manufacture and reducing the cost. Can also be reduced. In addition, the white reference can be referred to more reliably, and there is no difficulty such as loss of the incident light amount as in the cylindrical roller member 151 in the previous embodiment, and high correction accuracy can be stably obtained. Thus, the image quality can be stabilized.

When the original travels, the roller member 151 is used as shown in FIG.
As shown in FIG. 5A, there is a concern that a wobbling phenomenon may occur in the running document G due to the thickness and the strength of the document G. In the present embodiment, as shown in FIG. In addition, since a flat running path flush with the document table 3 can be ensured, it is not necessary to worry about the occurrence of such an adverse effect, and the document can be smoothly fed.

(Embodiment 3) This embodiment corresponds to claim 6. As shown in FIG. 6, a cleaning member 21 that comes into contact with a reference color surface of a rollable white belt-like member (reference color member) 153 and scrapes off foreign substances such as dirt and dust adhered to the reference color surface. By providing this, the reference color plane can be cleaned and homogenized, more accurate and stable correction can be performed, reliability can be improved, and higher image quality can be formed. In addition, since the number of abnormal parts is reduced, the correction operation can be simplified or the time required for correction can be reduced. Reference numeral 22 denotes a collection box for collecting scraped foreign substances.

Although not shown, such a cleaning member 21 can be similarly provided on the roller member 151 and the polygonal column 152. When the polygonal prism 152 is provided, the height position of the cleaning member 21 can be freely changed between a height position in contact with the reference color plane and a height position in which the polygonal prism 152 is allowed to rotate. do it.

(Embodiment 4) This embodiment is directed to Claim 7,
Corresponds to 8. In the conventional shading correction, since the operation refers to the white reference, it is not possible to cope with a variation in the input characteristics of the halftone. In the present embodiment, such a halftone correction is made possible, and FIGS. 7A and 7B show the configuration.

FIG. 7A shows a transition from white to black (in contrast to the case where the reference color surface of the rotating body 152 formed into the polygonal prism shown in FIG. 4A is all uniform white). Rotating body 15 having a reference color surface having multiple gradations
5 is assumed. Further, FIG. 7B shows (FIG.
(B) The white belt-shaped member 153 has a reference color surface having a plurality of different gradations from white to black, while the entire reference color surface is uniform white. 156 (the above is claim 7).

Instead of changing the gradation, the reflectivity may be changed in multiple steps from the setting of the reflectivity when referring to white (claim 8).

As described above, by changing the gradation and the reflectance, a change (variation) in the characteristics of the input element 11 due to the difference in the gradation and the reflectance can be grasped. As a result, the element characteristics can be made uniform. Further, such correction can be used to identify an abnormal part.

Conventionally, correction of only white was performed. However, as in the present embodiment, by confirming the intermediate density and black and performing image processing, a constant value is obtained even if the input characteristics of the halftone fluctuate. Image quality can be guaranteed. Also, when the relationship between the reflectance and the brightness is fluctuating, by monitoring this, detecting the fluctuation of the light amount of the light source and the fluctuation of the element sensitivity, and adjusting the input device and using it for input image processing, Image quality can be stabilized. Note that such a configuration in which the gradation and the reflectance of the reference color surface are changed can be applied to the roller member 151 and the roll-shaped white member 154.

(Embodiment 5) This embodiment corresponds to claim 9. At the time of shading correction, the reference color is
Naturally, it must be white, but when reading an original, if the reflectance of the reference color member disposed below the original travel path is high (high reflectance), for example, OHP
In the case of a transparent original such as a sheet or an original having a small paper thickness, there is a concern that light may be transmitted to the back side, and therefore, the white reference color may not be appropriate.

Such a problem does not occur in the case of reading on the original platen and the surface of the traveling original because the original reading position is different from the position of the reference color member. Must be taken into account.
Therefore, as shown in FIGS. 8A and 8B, such a problem is caused by configuring the surfaces having different reflectances to correspond to the exposure optical path when performing the shading correction and when reading the original. Can be eliminated.

That is, at the time of reference (at the time of shading correction)
Is corrected with the appropriate reflectance, and when reading the original,
By making the low-reflectance surface that does not reflect the irradiation light from the light source 9 face the input element 11, the transmitted light can be reduced even when inputting a thin original or a transparent original (an OHP sheet). Regardless, the image quality can be stabilized.

Specifically, half of the peripheral surface of the roller member 157 as a reference color member rotatably supported by the scanner base 1 is set as a white reference surface 157a, and the other peripheral surface is set as a low reflectance surface 157b. At the time of shading correction, as shown in FIG. 8A, a white reference surface 157a is made to correspond to the exposure optical path to the input element 11, and at the time of reading a document, as shown in FIG. The surface 157b is configured to correspond. With this configuration, it is possible to prevent the quality of the read image from deteriorating due to the transmission of light, and to stabilize and improve the image quality, even for a document that easily transmits light when reading the back side.

(Embodiment 6) In the present embodiment,
Corresponding to 0,11. At the time of shading correction, naturally, the reference color member is required to be uniform and white, but it is important that the reference color member is not referred to when the original is running, and is not an obstacle to the original running. You. Therefore, in the present embodiment, FIG.
As shown in (b), half of the peripheral surface of a roller member 158 as a reference color member rotatably supported by the scanner base 1 is used as a white reference surface 158a, and the other peripheral surface is used for traveling of the document G when the document is traveling. Slip surface 158 that does not interfere with
b.

With such a configuration, at the time of shading correction, as shown in FIG.
9A, the slip surface 158b corresponds to the running surface of the document G, and the document travels smoothly when reading the document. High image quality can be obtained by stabilization (claim 10).

As another configuration, FIG.
(B) As shown in FIG.
9, a rectangular opening 159 is provided at a portion other than the white reference reference position.
a, and when reading the original, the opening 159a is made to correspond directly below the CIS unit 8, and the opening 159a is formed.
Then, the document holder 159b as a travel assisting member for smoothing the document traveling is lifted to support the lower portion of the traveling document G and stabilize its traveling state (claim 11).

The document holder 159b can be moved to a raised position shown in FIG. 10B and a lower retracted position (not shown) by lifting means (not shown). Ribs 159c and guide rollers 159d arranged in such a manner as to slide on the lower surface of the document G to stabilize its running state. Note that such a white belt-shaped member 159 has a white background, but is shaded around the opening 159a so that the white reference reference position can be clearly identified. Although such a configuration is not shown and described, it can be similarly applied to a white belt-shaped member 153 as shown in FIG.

(Embodiment 7) This embodiment relates to a twelfth embodiment.
Corresponding to In this embodiment, the reference color member has a document feeding function, and a roller member 151 as a reference color member is connected to the drive source 22 via the drive force transmission member 21 as shown in FIG. When reading a document, the drive source 22 is activated, synchronized with the conveyance means, and the roller member 151 is driven to rotate to assist the document feeding movement. To improve the reading accuracy of the original.

In the configuration shown in FIG. 11B, one pulley 17 around which a white belt-shaped member 153 as a reference color member is wound is connected to a driving source 22 via a driving force transmitting member 21. When reading an original, the driving source 2
2, the white belt-shaped member 153 is rolled in synchronism with the conveying means to assist in the feeding movement of the original, thereby stabilizing the original conveying state regardless of the paper quality, and To improve the reading accuracy.

With the above configuration, it is possible to stably feed and move at a predetermined traveling speed even if the paper is thick or strong, or if the original is thin and stiff. And uniformity and stabilization of image quality can be achieved.

(Embodiment 8) This embodiment is directed to claim 13
Corresponding to In the present embodiment, for example, as shown in FIG. 12, a roll-type roll-shaped white member (reference color member) 254 formed so as to have the same spectral characteristics on the front and back surfaces is provided.
The lamp unit 4 is disposed immediately below the CIS unit 8 so that the lamp unit 4 can be moved directly below the roll-shaped white member 254. Therefore, by making it possible to refer to the front and back surfaces of the roll-shaped white member 254 in the position shown in the drawing, the shading correction of the scanner base 1 and the
The shading correction of the scanner upper part 2 can be sequentially performed.

Therefore, the conventional white reference member 16 provided on the document table 3 and indicated by a two-dot chain line is not required.
There is an advantage that the use area when using the document table 3 is expanded. The position of the lamp unit 4 at the time of shading correction of the conventional scanner base 1 is indicated by a two-dot chain line. Also,
Since the front side and the back side can be adjusted on the same basis, there is an advantage that the subsequent processing can be shared. In this embodiment, it is needless to say that the same function and effect as the roll-shaped white member 154 in the second embodiment can be obtained.

[0126]

According to the first aspect, the reference color plane of the reference color plane to be referred to is fixed for the fixed input element.
Since it is configured to be relatively movable, a contaminated portion of the reference color surface can be removed from the reading line. Therefore, the correction accuracy can be remarkably improved as compared with the case of reading the same line of a fixed white plate (there is a high possibility that a portion contaminated by the attachment of dust or the like exists) as in the related art.

According to the second aspect, since the reference color member is a rotating body, the reference color member is rotated and used, thereby avoiding a contaminated portion and removing a portion not exposed to the outside. It can be used as a reference point, and the influence of foreign matters such as dirt and dust can be reduced.

According to the third aspect, since the reference color member is a polygonal rotating polyhedron, a reference color surface having a certain area can be opposed (referenced) to the input element. The setting of the corresponding positional relationship between the element and the reference color member does not require high accuracy, making the device relatively easy to manufacture, and reducing the manufacturing cost.

According to the fourth aspect, since the reference color member is a rollable belt-like body, the reference color surface that can move with a certain area is opposed to (referenced to) the input element. Therefore, the setting of the corresponding positional relationship between the input element and the reference color member does not require a high degree of accuracy, making it relatively easy to manufacture the apparatus and reducing the manufacturing cost.

According to the fifth aspect, since the reference color member is a roll-type roll, a reference color surface movable with a certain area can be opposed to (referenced to) the input element. Therefore, the setting of the corresponding positional relationship between the input element and the reference color member does not require a high degree of accuracy, making it relatively easy to manufacture the apparatus and reducing the manufacturing cost.

According to the sixth aspect, since the cleaning member for cleaning the reference color member is provided in the main body of the reading device, the cleaning member can clean the reference color surface, and highly reliable correction can be performed. Can be realized.

According to the seventh aspect, since the reference color member has a plurality of reference color planes having different gradations, the intermediate density and the black (conventionally, only the correction of the white color has been performed) are confirmed. By performing image processing, a constant level of image quality can always be obtained even if the input characteristics of the halftone fluctuate.

According to the eighth aspect, since the reference color surface of the reference color member has a plurality of reflectivities, when the relationship between the reflectivity and the brightness is fluctuating, this is monitored and the light source of the device is monitored. A constant level of image quality can always be obtained by detecting the fluctuation of the light amount and the fluctuation of the element sensitivity and using the detected fluctuation for the input device adjustment and the input image processing.

According to the ninth aspect, the reference color surface of the reference color member facing the input element can be switched and used during the adjustment and when the original is running. Correction is performed using the reflectance, and when reading the original, a reference color surface having a gradation and a reflectance that prevents the original from being affected by reflected light is opposed to the input element, so that a thin original or a transparent original (an OHP sheet) can be read. ), Etc., stable image quality can be ensured.

According to the tenth aspect, the portion of the reference color member facing the input element when the original travels has surface characteristics suitable for the original travel. At the time of reading a document, the document runs smoothly, for example, by opposing a portion having a surface characteristic that particularly improves the surface slip,
The document can be run properly, and the stability of the image quality can be improved.

According to the eleventh aspect, the opening for forming the auxiliary member for smoothing the original running corresponding to the original running path is formed, so that an appropriate correction is made at the time of reference and the original runs smoothly at the time of reading the original. In particular, by opposing a portion having a changed surface shape so that the original document can travel properly.

According to the twelfth aspect, since the portion of the reference color member facing the input element when the original is running has an original feeding function, the corresponding positional relationship between the input element and the running original can be more stably established. As a result, the influence of the thickness and warpage of the document can be reduced, so that the image quality can be stabilized regardless of the type of the document.

According to the thirteenth aspect, since the reference color member also serves as a reference when reading the front side, a reference color member for front surface input is not required. Further, since the front surface and the back surface can be adjusted on the same basis, there is an advantage that the subsequent processing can be shared.

According to the fourteenth aspect, since the correction of the input element by the reference color member is performed at a fixed timing such as when the power is turned on, more reliable correction can be performed, and the image quality can be stabilized.

According to the fifteenth aspect, the reference color plane of the reference color member is moved relative to the input element, and a plurality of lines of different parts are input. Processing can be performed excluding the data, and the correction accuracy can be stabilized and improved.

According to the sixteenth aspect, since the correction is performed at a constant timing, the correction accuracy can be further improved and the image quality can be stabilized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a conventional image reading apparatus.

FIG. 2 is a main part configuration diagram of the image reading apparatus according to the first embodiment of the present invention.

FIG. 3 is a view for explaining a difficulty of the first embodiment in the second embodiment.

FIG. 4 is a main part configuration diagram of Embodiment 2;

FIG. 5 is a drawing for explaining the operation and effect of the second embodiment.

FIG. 6 is a main part configuration diagram of Embodiment 3;

FIG. 7 is a main part configuration diagram of Embodiment 4.

FIG. 8 is a main part configuration diagram of Embodiment 5;

FIG. 9 is a configuration diagram of a main part of the sixth embodiment.

FIG. 10 is an explanatory diagram of another configuration of a main part of the sixth embodiment.

FIG. 11 is a main part configuration diagram of Embodiment 7;

FIG. 12 is an explanatory diagram of a main part configuration of the eighth embodiment.

[Explanation of symbols]

 1, 2-reading device main body 8- reading means 11- input element 21- cleaning member 151-159- reference color member 254- reference color member 159b- travel assist member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuru Tokuyama 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Inside (72) Inventor Mihoko Tanimura 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside (72) Inventor Noriyasu Yasuoka 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Eiji Saiko 22-22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Sharp Corporation F term (reference) 5B047 AA01 AB02 BA07 BB02 BC05 BC09 BC11 BC14 CA30 DA04 DC06 5C072 AA01 BA08 BA13 CA02 DA02 DA04 EA05 FB12 LA15 LA18 UA02 WA02 XA01 5C077 LL19 MM27 PP06 SS01 SS03 TT06

Claims (16)

[Claims] An image forming apparatus is provided in an image forming apparatus for reading image information of a document, processing the read image, forming an output image, and printing or transmitting the image. In an image reading apparatus configured to read, a reading unit of a 1 × optical system for reading image information on the back side of a running document is fixed to a reading device main body, and an input element of the reading unit is corrected. An image reading device, wherein the reference color member is provided immediately below the document traveling position, and a reference color surface of the reference color member is relatively movable with respect to the input element. 2. The image reading apparatus according to claim 1, wherein the reference color member is a rotating body. 3. The image reading apparatus according to claim 1, wherein the reference color member is a polygonal column-shaped rotating polyhedron. 4. The image reading apparatus according to claim 1, wherein the reference color member is a rotatable belt-like body. 5. The image reading apparatus according to claim 1, wherein the reference color member is a take-up roll. 6. The image reading apparatus according to claim 1, wherein a cleaning member for cleaning the reference color member is provided in the reading apparatus main body. 7. The image reading apparatus according to claim 1, wherein the reference color member has a plurality of reference color planes having different gradations. 8. The image reading apparatus according to claim 1, wherein a reference color surface of the reference color member has a plurality of reflectances. 9. The apparatus according to claim 7, wherein a reference color surface of said reference color member facing said input element can be switched and used at the time of adjustment and at the time of document traveling.
An image reading device according to claim 1. 10. The image reading apparatus according to claim 9, wherein a portion of the reference color member facing the input element when the document runs has a surface characteristic suitable for running the document. 11. An apparatus according to claim 1, wherein a portion of said reference color member facing said input element at the time of document traveling has an opening formed therein for supporting a document traveling path with a traveling auxiliary member for facilitating document traveling. The image reading device according to claim 9, wherein: 12. The image reading apparatus according to claim 2, wherein a portion of the reference color member facing the input element when the document is running has a document feeding function. . 13. The image reading apparatus according to claim 4, wherein the reference color member also serves as a reference when reading the front side. 14. The input device according to claim 1, wherein the correction of the input device by the reference color member provided in the image reading device according to any one of claims 1 to 13 is performed at a fixed timing such as when power is turned on. Correction method. 15. The image reading apparatus according to claim 1, wherein a reference color surface of said reference color member is relatively moved with respect to said input element, and said reference color information is transmitted a plurality of times. A method for correcting an input element, comprising: reading and correcting the input element based on the read data. 16. The apparatus according to claim 1, wherein the correction of the input element is performed at a fixed timing such as when power is turned on.
6. The method for correcting an input element according to 5.