JPH08331380A - Terminal equipment having facsimile function - Google Patents

Abstract

PURPOSE: To provide the terminal equipment having a facsimile function by which a gain width of gradation at a halftone is decided more properly. CONSTITUTION: A black image detection section 13 detects whether or not a black level part is in existence in image data of a transmission original in the case of facsimile transmission, and a facsimile control section 2 conducts shading correction by using a white level reference value of a white original and a shading correction value stored in advance in a 1st shading correction value white reference level storage means 10 when the black level is present and using a white level reference value of a tip part of a white original and a shading correction value stored in advance in a 2nd shading correction value white reference level storage means 11 when the black level is not present.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal device having a facsimile function, such as a facsimile device or a compound terminal device having a facsimile function, and is capable of more appropriately determining the gain width of gradation in a halftone. The present invention relates to a terminal device having a facsimile function.

[0002]

2. Description of the Related Art Conventionally, in a terminal device having a facsimile function, as shown in FIG. 9, for example, a white plate 102 is arranged at a position facing a reading sensor 101, and the white plate 102 is read by the reading sensor 101, for example, as shown in FIG. The maximum value of the output indicated by a thick line in FIG. 10 is stored as a white reference value indicated by a thin line in the figure, and the difference between the white reference value and the detection value at each dot of the reading sensor 101 and the white reference value is indicated by an arrow in the figure. The shading correction value indicated by is stored. Then, when the transmission document is actually read, the corrected image data obtained by adding the shading correction value to the image data output by the reading sensor 101 is output to the telephone line or the printing unit.

Further, since the background of the original is generally white,
As shown in FIG. 11, when the leading edge of the original 103 passes between the reading sensor 101 and the white plate 102, the leading edge of the original or the width of the original cannot be detected. In the terminal device having a function, a leading edge detection sensor is provided separately from the reading sensor 101 to detect the leading edge of the document, and a sensor provided separately detects the width of the document.

[0004]

By the way, in a conventional terminal device having a facsimile function for determining a white reference value and a shading correction value using a white plate, when the background of the original is a color background, the gradation of Since the gain width is large, there is a problem that the resolution in the halftone is lowered. Further, since the portion facing the reading sensor 101 is white, in the case of a thin document such as a document, a part of the light output from the light source unit 104 is transmitted through the document and then reflected by the white plate, and the document is further reflected. As a result of being transmitted through the reading sensor 101 and being read by the reading sensor 101, characters and pictures written on the back of the document are read and transmitted while overlapping the characters and pictures on the front side of the document,
It may be copied.

Further, since another sensor is required to detect the leading edge of the document and another sensor is required to detect the document size, the number of parts is increased and the cost is reduced. There is also the problem of being disadvantageous.

The present invention has been made in view of the above circumstances, and has a facsimile function capable of increasing the resolution of a halftone of a color background document and eliminating the risk of reading characters and pictures on the back side. It is intended to provide a terminal device.

[0007]

In order to achieve the above object, a terminal device having a first facsimile function of the present invention has a white reference value and shading of a white original determined by reading the leading edge of the white original in advance. First storage means for storing the correction value, and second storage means for storing the white reference value and the shading correction value of the transmission original determined by reading the leading end portion of the transmission original every time the original is facsimile-transmitted.
Using the white reference value and the shading correction value stored in the first storage means, it is determined whether or not the image data of the read transmission original has a black portion. If there is no black portion, the second storage means stores the black portion. The present invention is characterized in that shading correction means is provided which uses the white reference value and the shading correction value to perform shading correction using the white reference value and the shading correction value of the first storage means when there is a black portion.

In order to achieve the above-mentioned object, the terminal device having the second facsimile function of the present invention further comprises a first storage means for storing the white reference value and the shading correction value of the white plate by reading the white plate in advance. Second storage means for reading the front end portion of the transmission original at the time of facsimile transmission and storing the white reference value and the shading correction value of the transmission original;
Using the white reference value and the shading correction value stored in the storage means, it is determined whether or not the image data of the read original has a black portion. If there is no black portion, the white reference value of the second storage means is determined. A shading correction unit for performing shading correction using the white reference value and the shading correction value of the first storage unit by using the value and the shading correction value when there is a black portion is provided.

Further, in order to achieve the above-mentioned object, the terminal device having the third facsimile function of the present invention, when the portion facing the reading sensor is colored black or a color close to black, and the original is transmitted by facsimile. , A means for detecting the leading edge position of the original by discriminating the black-and-white pattern of the original, a means for determining the paper size based on the black-and-white pattern of the leading edge of the original, reading the leading edge of the transmitted original, and reading the white reference value and the shading correction value. And means for determining

In addition, in order to achieve the above-mentioned object, the terminal device having the fourth facsimile function of the present invention colors the portion facing the reading sensor black or a color close to black, and preliminarily sets the leading edge of the white original. First storage means for reading a portion and storing the white reference value and shading correction value of a white original; and means for detecting the leading edge position of the paper by determining the black-and-white pattern of the leading edge of the transmitted original every time the original is faxed. A means for determining the paper size based on the black-and-white pattern at the leading edge of the document, a second storage means for reading the leading edge of the transmission document and storing the white reference value and the shading correction value for the transmission document, and the first storage means. It is determined whether or not there is a black portion in the white document that is read in advance by the read white reference value and the shading correction value. If there is no black portion, the second storage means Using white reference value and a shading correction value, if there is a black portion, characterized in that a shading correction unit that performs shading correction using the white reference value and the shading correction value of the first storage means.

[0011]

In the terminal device having the first facsimile function of the present invention, it is detected in advance that the front end of the white original passes through the reading sensor, and following this detection, the front end of the white original is read and the white original is detected. The white reference value and the shading correction value are determined and stored in the first storage means.

Here, in order to read the leading edge of the white original, a sensor is required to detect that the leading edge of the original has passed the reading sensor. This sensor is composed of a reading sensor and a sensor different from the conventional one. However, by coloring the portion facing the reading sensor with a color different from that of the original, the reading sensor can also be used as a sensor for detecting the leading edge. When the leading edge of the white original is detected by the reading sensor, it is preferable that the output difference of the reading sensor depending on the presence or absence of the original is large. Therefore, it is preferable to color the portion facing the reading sensor black or a color close to black.

Even when a document is transmitted by facsimile, the leading edge of the transmitted document is detected as in the case of a white document.
Subsequently, the white reference value and the shading correction value of the transmission original are determined by reading the leading end of the transmission original, and stored in the second storage means. Whether or not there is a black portion from the data read using the white reference value and the shading correction value stored in the first storage means in parallel with the storage of the white reference value and the shading correction value of the transmission document. Is determined.

If there is no black portion, it is considered that a background or halftone character or picture has been read over the entire reading line, and therefore white stored in the second storage means having a small tone gain width. It is considered that the reference value and the shading correction value are correct white reference value and shading correction value taking the background color into consideration, and the shading correction is performed using the white reference value and the shading correction value of the second storage means. Be seen.

If there is a black portion, it is considered that a character or a picture having a black reference value written on the background is read, so that it is stored in the first storage means having a large tone gain width. It is considered that the white reference value and the shading correction value are the correct white reference value and the shading correction value, and the shading correction is performed using the white reference value and the shading correction value of the first storage means.

In the terminal device having the second facsimile function of the present invention, the white reference value and the shading correction value are determined by reading the white plate by the reading sensor and stored in the first storage means.

Further, the white reference value and the shading correction value of the transmission original are determined by reading the leading end of the transmission original during facsimile transmission and stored in the second storage means.

Here, in order to read the leading edge of the white original, a sensor is required to detect that the leading edge of the original has passed the reading sensor. In this case, a white plate is placed facing the reading sensor. Therefore, it is necessary to be able to detect the leading edge of the transmission original by a sensor other than the reading sensor as in the conventional case.

However, after the white reference value and the shading correction value of the white plate are stored in the first storage means, the white plate is removed before the facsimile transmission, and the part facing the reading sensor is colored black or a color close to black. In this case, the leading edge and size of the transmission original can be detected by the reading sensor, and reading of characters and pictures on the back surface of the transmission original can be prevented.

In parallel with the storage of the white reference value and the shading correction value of the transmission original, the white reference value and the shading correction value stored in the first storage means are used to store the image data read by the reading sensor. It is determined whether there is a black portion.

If there is no black portion, it is considered that a background or halftone character or picture has been read over the entire reading line, so the white stored in the second storage means having a small tone gain width. It is considered that the reference value and the shading correction value are correct white reference value and shading correction value taking the background color into consideration, and the shading correction is performed using the white reference value and the shading correction value of the second storage means. Be seen.

If there is a black portion, it is considered that a character or a picture with a black reference value written on the background is read, and therefore, it is stored in the first storage means having a large gradation gain width. It is considered that the white reference value and the shading correction value are the correct white reference value and the shading correction value, and the shading correction is performed using the white reference value and the shading correction value of the first storage means.

In the terminal device having the third facsimile function of the present invention, when the document passes through the reading sensor, the output of the reading sensor changes corresponding to the black-and-white pattern of the document, so the output of the reading sensor changes. By detecting the presence or absence of the document, it is possible to detect that the leading edge of the document has passed the reading sensor, and it is possible to detect the size of the document.

Further, since the portion facing the reading sensor is colored black or a color close to black, most of the light transmitted through the document is absorbed by the portion facing the reading sensor, and characters or characters on the back surface of the document are absorbed. There is no fear of reading a picture, and it is possible to prevent characters or pictures on the back side from being transmitted or printed.

Further, since there is no possibility that the characters or pictures on the back side of the original will be read, the error due to the reading of the characters or pictures on the back side is determined when the white reference value and the shading correction value are determined by reading the leading edge of the transmission original. Can be lost,
It is possible to accurately determine the white reference value and the shading correction value of the transmission original.

In the terminal device having the fourth facsimile function of the present invention, the output of the reading sensor changes corresponding to the black-and-white pattern of the original because the leading edge of the white original has passed the reading sensor in advance. By detecting whether the output of the reading sensor has changed, it is possible to detect that the leading edge of the document has passed the reading sensor and the width of the document. There is no need to provide a sensor.

Following the detection of the leading edge of the original, the leading edge of the white original is read, the white reference value and the shading correction value of the white original are determined, and stored in the first storage means.

Further, at the time of facsimile transmission, the front end portion of the transmission original is read in the same manner as in the case of a white original, the front end position of the transmission original and the width of the transmission original are detected, and the white reference value and shading of the transmission original are detected. The correction value is determined and stored in the second storage means.

Here, since the portion facing the reading sensor is colored black or a color close to black, the light transmitted through the transmission original is prevented from being reflected by the reading sensor, and the characters and pictures on the back surface are read. Since there is no fear of being read by the sensor, the white reference value and the shading correction value of the transmission original are accurately determined.

In parallel with the storage of the white reference value and the shading correction value of the transmission original, the white reference value and the shading correction value stored in the first storage means are used to read one line of the line read by the reading sensor. It is determined whether or not there is a black portion in the image data.

If there is no black portion, it is considered that a background or halftone character or picture is read over the entire reading line, so the white reference stored in the second storage means having a small gradation gain width. It is considered that the white reference value and the shading correction value are correct in consideration of the value, the shading correction value, and the background color, and the shading correction is performed using the white reference value and the shading correction value of the second storage unit.

Further, when there is a black portion, it is considered that a character or a picture having a black reference value written on the background is read, and therefore, the white stored in the first storage means having a large gradation gain width. It is considered that the reference value and the shading correction value are the correct white reference value and the shading correction value, and the shading correction is performed using the white reference value and the shading correction value of the first storage means.

Here, since the portion facing the reading sensor is colored black or a color close to black, the light transmitted through the transmission original is prevented from being reflected by the reading sensor, and the characters and pictures on the back surface are read. Since there is no danger of being read by the sensor, there is no risk of characters or pictures on the back side being transmitted or printed.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A terminal device having a facsimile function according to an embodiment of the present invention will be specifically described with reference to the drawings.

As shown in the block diagram of FIG. 1, in the terminal device having the facsimile function according to the embodiment of the present invention, the facsimile is operated in accordance with the operation of the operation unit 1 for operating the facsimile function of the terminal device. The facsimile control unit 2 that controls the entire function operates, and the leading edge of the white original inserted in the reading unit 3 is read.

As shown in the perspective view of FIG.
Is provided with a reading sensor 6 including a light source unit 4 and a sensor unit 5 including a CCD for detecting a light beam emitted from the light source 4 and reflected by an original. The reading sensor 6 faces the reading sensor 6 and is colored black. The blackboard 7 is arranged.

As shown in the schematic plan view of FIG. 3, when a white manuscript 8 is inserted into the reading section 3, a part of the blackboard 7 is covered with the white manuscript 8 and the reading sensor 6 reads a black-and-white pattern. . Therefore, the leading edge of the white original 8 is detected by detecting that the reading sensor 6 has changed from detecting the reflected light from the black-colored blackboard 7 to detecting the reflected light from the black-and-white pattern. Can be detected.

In the reading sensor 6, along with the leading edge of the original, the originals A3, B4, and A4 sent based on the center are sent.
As shown in the schematic view of FIG. 4, the leading edge detection check for detecting the leading edge of the document within the A4 document length (216 mm), which has the smallest size in the center, can be automatically detected. A region is set, and black and white determination check regions are provided on both sides of the check region up to the document length of B4 (256 mm), and A3 is provided on both sides of the check region.
The black-and-white judgment check area is set up to the original length (297 mm).

Then, the front end of the white original 8 is detected by detecting that the output of the check area has changed from the output corresponding to black to the output corresponding to white in the facsimile controller 2.

Further, following the detection of the leading edge of the original, the leading edge of the white original 8 is read, the white reference value and the shading correction value of the white original 8 are determined as shown in FIG. 5, and the first reference shown in FIG. The one shading correction value is stored in the white reference value storage unit 10.

After that, when the transmission original is inserted into the reading unit 3 when the facsimile transmission is executed, the front end of the original is detected in the same manner as the detection of the front end of the white original 8, and based on the monochrome pattern continuously read. The document size of the transmitted document is determined by the document size determination unit 9.

That is, since the black and white of the black and white pattern is switched at the edge of the transmission document, the above-mentioned check area
It is possible to determine the size of the transmission original by determining the black and white of the check area based on the output of.

Here, black and white judgment checkpoints for B4 document lengths (256 mm) on both sides of the leading edge detection check area set at the center, and A3 document lengths (A3) for both sides are provided. 297 mm), the check points for black and white judgment are set. Therefore, if all the check points are black, it is judged that there is no transmission original, and the central check point detects white. If all the checkpoints on both sides thereof are black, it is determined that there is a document of A4 size (or smaller than this, for example, B5 size). If the checkpoint is black, it is determined that there is a B4 size document, and if all the checkpoints are white, it is determined that there is an A3 size document.

In this embodiment, in order to prevent erroneous detection, black and white in each check area are detected at points indicated by arrows with three appropriate intervals in each check area. The number of points in each check region can be selected from one or more arbitrary numbers.

Further, following the detection of the front end of the transmission original, the reading unit 3 reads the front end of the transmission original, for example, as shown in FIG.
The white reference value and the shading correction value of the transmission original are determined as shown in (4) and stored in the second shading correction value white reference value storage unit 11.

Further, following the detection of the leading edge of the transmitted document, the white reference value and the shading correction value stored in the first shading correction value white reference value storage unit 10 are transferred to the shading correction value white reference value storage unit 12, Based on the white reference value and the shading correction value, the facsimile control unit 2 sequentially reads the transmission document from the leading edge, and the black image detection unit 13 determines whether or not there is a black portion in the read image data in each reading line. judge.

If there is a black portion, the facsimile control unit 2 causes the shading correction value white reference value storage unit 1
The white reference value and the shading correction value of 2, that is, the first shading correction value, the white reference value and the shading correction value of the white original 8 stored in the white reference value storage unit 10 perform the shading correction of the image data, and there is no black portion. In this case, the second shading correction value white reference value storage unit 11
The white reference value and the shading correction value of the transmission original stored in step S4 are transferred to the shading correction value white reference value storage unit 12, and the facsimile control unit 2 performs the shading correction based on the white reference value and the shading correction value of the transmission original. To do.

At the time of reading the transmission original, since the blackboard 7 facing the reading sensor 6 is colored black, the light transmitted through the transmission original is absorbed by the blackboard 7 and may enter the reading sensor 6 side. Because it disappears
Even if the transmitted document is thin, there is no possibility that the characters or pictures written on the back side of the transmitted document will overlap the characters or pictures on the front side and will be read by the reading sensor 6, and the characters or pictures on the back side will not be accidentally transmitted.

As described above, the read line having no black portion is subjected to the shading correction by the white reference value and the shading correction value of the white original document 8. Therefore, as shown in FIG. Even if there is, the gain width of each gradation is sufficiently large, and the resolution of the halftone can be maintained above a certain level.

Since the reading line having a black portion is shading-corrected by the white reference value and the shading correction value of the transmission original, the gain width of each gradation is compressed and the halftone resolution as shown in FIG. 8, for example. Is maintained above a certain level.

In this way, the image data of the reading line without the black portion which is shading-corrected by the white reference value and the shading correction value of the white original document 8 and the image which is shading-corrected by the white reference value and the shading correction value of the transmission original document. The data is sequentially transferred from the facsimile control unit 2 to the facsimile modem unit 14, modulated into a facsimile signal and output to the telephone line.

A facsimile signal input from the telephone line to the facsimile modem unit 14 is demodulated by the facsimile modem unit 14 and then transferred to the facsimile control unit 2, and the printing unit 15 is driven to print. Further, the operating state of the facsimile function is displayed on the display unit 16.

In a terminal device having a facsimile function according to another embodiment of the present invention, a white plate is arranged facing the reading sensor 6 of the reading unit 3, and at the start of transmission, the white plate is read prior to reading the transmission original. Scan to determine the white reference value and shading correction value for the white board,
It is stored in the first shading correction value white reference value storage unit 10, and further stored in the shading correction value white reference value storage unit 12.

When the transmission document is read, the leading edge of the transmission document reaches the reading sensor 6 is detected by the leading edge detection sensor, and the leading edge of the transmission document is continuously read by the reading sensor 6 to determine the white reference value of the transmission document. And the shading correction value are determined and stored in the second shading correction value white reference value storage unit 11.

At the same time, it is determined whether or not there is a black portion in the image data of the transmission document by the shading correction value white reference value storage unit 12
The black image detection unit 13 makes a determination based on the white reference value and the shading correction value of the white plate stored in the table, and when there is a black image, the white reference value and the shading of the white plate stored in the shading correction value white reference value storage unit 12 Shading correction is performed based on the correction value, and when there is no shading correction value, the white reference value and the shading correction value of the transmission original stored in the second shading correction value white reference value storage unit 11 are transferred to the shading correction value white reference value storage unit 12. Then, the shading correction is performed based on the white reference value and the shading correction value of the transmission original.

The size of the transmission original is detected by a size detection sensor group provided separately from the reading sensor 6, and is determined by the original size determination unit 9.

Since the other construction, operation and effect of this embodiment are the same as those of the above-mentioned one embodiment, their description will be omitted to avoid duplication.

In a terminal device having a facsimile function according to another embodiment of the present invention, a white plate is arranged in advance so as to face the reading sensor 6 of the reading section 3, and the white plate is read to set the white reference value of the white plate. The shading correction value is determined, stored in the first shading correction value white reference value storage unit 10, and further stored in the shading correction value white reference value storage unit 12. After this, remove this white plate,
A blackboard 7 colored in black or a color close to black is arranged so as to face the reading sensor 6.

At the time of reading the transmission original, if the image data read by the reading sensor 6 has a black portion, the first shading correction value white reference value storage unit 10
Shading correction is performed using the white reference value and shading correction value of the white plate stored in the second white shading correction value and the white reference value and the shading correction value of the transmission document stored in the white reference value storage unit 11 when there is no black portion. I am trying to correct shading.

Since the other construction, operation and effect of this embodiment are the same as those of the above-mentioned one embodiment, these explanations are omitted to avoid duplication.

[0061]

As described above, in the terminal device having the first facsimile function of the present invention, when there is a black portion in the image data of the transmission original, the white original of the white original stored in the first storage means is stored. Shading correction having a large gradation gain width is performed using the reference value and the shading correction value, and when there is no black portion in the image data of the transmission document, the white reference value and the shading correction value of the transmission document stored in the second storage means. Since the shading correction with a small tone gain width is performed by using, the gain width in the halftone is determined more appropriately, the resolution of the halftone of the color background original is increased, and the print image quality of the halftone is improved. be able to.

Further, in the terminal device having the first facsimile function of the present invention, especially when the portion facing the reading sensor is colored black or a color close to black, the leading edge and size of the transmission original are set to the reading sensor. Since it can be detected by using it, the number of parts can be reduced and the cost can be reduced, and the light transmitted through the transmission original can be prevented from being reflected on the reading sensor. It is possible to prevent the picture from being transmitted accidentally, and to accurately determine the white reference value and the shading correction value of the transmission original.

In the terminal device having the second facsimile function of the present invention, when there is a black portion in the image data of the transmission original, the shading is performed using the white reference value of the white plate and the shading correction value stored in the first storage means. Since the correction is performed and the shading correction is performed using the white reference value and the shading correction value of the transmission document stored in the second storage means when there is no black portion, the resolution of the halftone of the color document can be increased.

In the terminal device having the second facsimile function of the present invention, in particular, after storing the white reference value and the shading correction value of the white plate in the first storage means, the white plate is removed and the portion facing the reading sensor is removed. When coloring in black or a color close to black, the leading edge and size of the transmitted original can be detected using a reading sensor,
Since the number of parts can be reduced to reduce costs and the light transmitted through the transmission document can be prevented from being reflected by the reading sensor, letters and pictures written on the back side of the transmission document can be mistakenly transmitted. In addition, the white reference value and the shading correction value of the transmission original can be accurately determined.

In the third terminal device having the facsimile function of the present invention, the portion facing the reading sensor is colored black or a color close to black, and when the document is transmitted by facsimile, the monochrome pattern of the document is determined. Since it is equipped with a means for automatically detecting the leading edge of the paper and a means for determining the paper size based on the black-and-white pattern of the leading edge of the original, a sensor for detecting the leading edge of the transmission original and a sensor for detecting the size of the transmission original are separately provided. Since it is not necessary to provide it, the number of parts can be reduced and the cost can be reduced.

Further, since the portion facing the reading sensor is colored in black or a color close to black, most of the light transmitted through the document is absorbed by the portion facing the reading sensor, and characters or characters on the back surface of the document are absorbed. There is no fear of the picture being read, it is possible to prevent the letters and pictures written on the back side of the transmission original from being mistakenly transmitted, and it is possible to accurately determine the white reference value and shading correction value of the transmission original. .

The terminal device having the fourth facsimile function of the present invention uses the white reference value and the shading correction value of the white original document stored in the first storage means when the image data of the transmission original document has a black portion. Shading correction with a large gradation gain width is performed, and when there is no black portion in the image data of the transmission original, the gradation gain width is small with the white reference value and the shading correction value of the transmission original stored in the second storage means. Since the shading correction is performed, the gain width in the halftone can be determined more appropriately, the resolution of the halftone of the color background document can be increased, and the print image quality of the halftone can be improved.

In addition, when the portion facing the reading sensor is colored in black or a color close to black and the original is sent by facsimile, a black-and-white pattern of the original is determined to automatically detect the leading edge position of the paper. Since it has means for determining the paper size based on the black and white pattern at the leading edge of the document,
Since it is not necessary to separately provide a sensor for detecting the leading edge of the transmission document or a sensor for detecting the size of the transmission document, the number of parts can be reduced and the cost can be reduced.

Further, since the portion facing the reading sensor is colored in black or a color close to black, most of the light transmitted through the document is absorbed by the portion facing the reading sensor, and characters on the back surface of the document and There is no fear of the picture being read, it is possible to prevent the letters and pictures written on the back side of the transmission original from being mistakenly transmitted, and it is possible to accurately determine the white reference value and shading correction value of the transmission original. .

[Brief description of drawings]

FIG. 1 is a block diagram of the present invention.

FIG. 2 is a perspective view of a main part of a reading unit according to the present invention.

FIG. 3 is a schematic plan view of a reading unit of the present invention.

FIG. 4 is a schematic diagram showing an arrangement of check areas set in the reading sensor of the present invention.

FIG. 5 is a voltage characteristic diagram showing a white reference and a shading correction value of a white original (or a white plate).

FIG. 6 is a voltage characteristic diagram showing image data subjected to shading correction using the output of the reading sensor, the white reference of the white plate, and the shading correction value.

FIG. 7 is a voltage characteristic diagram showing a white reference and a shading correction value of a transmission original.

FIG. 8 is a voltage characteristic diagram showing image data subjected to shading correction using the output of the reading sensor, the white reference of the transmission original, and the shading correction value.

FIG. 9 is a perspective view of a main part of a conventional reading unit.

FIG. 10 is a voltage characteristic diagram showing a white reference and a shading correction value of a white plate.

FIG. 11 is a schematic plan view of a reading unit of a conventional example.

[Explanation of symbols]

 1 Operation Section 2 Facsimile Control Section 3 Reading Section 6 Reading Sensor 7 Blackboard 8 White Original 9 Original Size Determining Section 10 First Shading Correction Value White Reference Storage Section 11 Second Shading Correction Value White Reference Storage Section 12 Shading Correction Value White Reference Storage Part 13 Black image detection unit

Claims (4)

[Claims] 1. A first storage unit for storing a white reference value and a shading correction value of a white original, which is determined by reading the front end of the white original in advance, and the front end of the original is read every time the original is sent by facsimile. Second storage means for storing the determined white reference value and shading correction value of the transmission original, and a black portion in the image data of the transmission original read using the white reference value and the shading correction value stored in the first storage means. If there is no black portion, the white reference value and shading correction value of the second storage means are used, and if there is a black portion, the white reference value and shading correction of the first storage means are used. A terminal device having a facsimile function, comprising: a shading correction unit that performs shading correction using a value. 2. A first storage unit for storing a white reference value and a shading correction value of the white plate by reading the white plate in advance, and a white reference value and a shading correction value of the transmission original by reading the front end of the transmission document during facsimile transmission. It is determined whether there is a black portion in the image data of the transmission document read by using the second storage unit that stores the white reference value and the shading correction value that are stored in the first storage unit. Shading correction means for performing shading correction using the white reference value and shading correction value of the second storage means when there is no black portion and using the white reference value and shading correction value of the first storage means when there is a black portion. A terminal device having a facsimile function, characterized by being provided with. 3. A means for detecting the position of the leading edge of the paper by determining the black and white pattern of the original when sending the original by facsimile by coloring the portion facing the reading sensor black or a color close to black, and A terminal device having a facsimile function, comprising: a unit for determining a sheet size based on a black-and-white pattern; and a unit for reading the leading end of a transmission document to determine a white reference value and a shading correction value. 4. A first storage means for coloring the portion facing the reading sensor in black or a color close to black and reading the leading end portion of the white original in advance to store the white reference value and the shading correction value of the white original. Each time a document is sent by facsimile, a means for determining the black-and-white pattern at the leading edge of the transmission document to detect the leading edge position of the paper, a means for determining the paper size based on the black-and-white pattern at the leading edge of the document, The second storage means for reading and storing the white reference value and the shading correction value of the transmission original, and the black portion in the image data of the transmission original read using the white reference value and the shading correction value stored in the first storage means. If there is no black portion, the white reference value and the shading correction value of the second storage means are used. If there is a black portion, the white reference value of the first storage means is used. A terminal device having a facsimile function, comprising: a shading correction unit that performs shading correction using a reference value and a shading correction value.