JPH04137664U - image reading device - Google Patents

Abstract

(57) [Summary] [Purpose] To ensure the maximum reading range of the manuscript. [Structure] A marker 12 is provided along the sub-scanning direction outside the document reading range of the document table 2, and prior to main scanning by the optical reading section 4, the position of the marker 12 along the main scanning direction is determined by the distance from the main scanning start point. In addition to detecting the marker position as By doing so, it is controlled so that reading always starts from a position that is a certain distance from the marker 12, and the optical reading section 4 and document table 2
The assembly error that exists between the two positions is absorbed by correcting the reading start position when reading the document.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea is an image reading system that maximizes the reading range of the original. Regarding equipment.

0002

[Conventional technology]

Image reading devices used in facsimile machines, image scanners, etc. In order to read the dimensional image data, the document is fed in the sub-scanning direction and is A method of main scanning in intersecting directions is used. Conventional image reading device shown in Figure 6 1 carries a document placed on a fixed document table 2 into an apparatus main body 3 that supports the document table 2. A so-called document table that is read by two-dimensional scanning with an optical reading section 4 installed on the A fixed method is adopted. The optical reading section 4 reads image information in the main scanning direction. It has a built-in line sensor 5 for reading, and the reading position of this line sensor 5 can be By moving line by line in the sub-scanning direction and performing main scanning between sub-scanning, Original image information can be read.

0003

[Problem that the idea aims to solve]

The above-mentioned conventional image reading device 1 is difficult to attach the original platen 2 to the main body 3 of the device. It is necessary to strictly control the degree of Even if the document table 2 is slightly bent relative to the main body 3, If the main scanning start position of the optical reading section 4 is assembled in the sub-scanning direction. The reference line Lr obtained by connecting the direction and the manuscript reading line with diagonal lines on the manuscript table Parallelism with the boundary line Lb that defines the left end of the cutting range cannot be obtained. For this reason, the main race There may be variations in the distance from the reference line Lr to the boundary line Lb for each line to be scanned. It becomes. However, the optical reading unit 4 detects the distance from the reference line Lr to the boundary line Lb. Image reading always starts from a position a certain distance from the reference line Lr, regardless of the Since the configuration is such that a document placed directly on the document table 2 can also be read by the optical reader inside the device main body 3. With respect to the main scanning direction of the cut-out portion 4, it is distorted and opposed to the main scanning direction. As a result, e.g. Optical scanning is useful when scanning originals filled with image information. As the sub-scanning of section 4 progresses, a part of the document enters the document reading range of optical reading section 4. There were times when I went out of line. In such cases, an image scanner can Of course, this can lead to incomplete reading results, and facsimile machines are rare. Part of the desired information may be omitted from being transmitted, especially when scanning with high scanning density. The more finely read a device becomes, the more likely it is that insufficient reading range will become a problem. I was faced with such issues.

0004

[Means to solve the problem]

This idea solves the above problem, and allows the user to read the manuscript placed on the manuscript table. , reads two-dimensional image information by repeating main scanning and sub-scanning by the optical reading section. In an image reading device that uses Markers provided along the main scanning direction and the main scanning direction prior to main scanning by the optical reading section Marker detection that detects the position of the marker along the direction as a distance from the main scanning start point section, and the marker position detected by the marker detection section during each main scan up to the previous time. The marker positions detected during main scanning are compared and read according to the comparison error obtained. Correct the reading start position and always start reading from a position that is a certain distance from the marker. The invention is characterized by comprising a control means for controlling the start of the process.

[0005]

[Effect]

This idea places markers along the sub-scanning direction outside the document reading range on the document table. , prior to main scanning by the optical reading section, the position of the marker along the main scanning direction; is detected as the distance from the main scanning start point, and is detected each time the main scanning is performed. Compare the marker positions including the marker positions detected along with the previous main scan. By correcting the reading start position during main scanning based on the comparison error obtained, control so that reading always starts from a position a certain distance from the marker. Reads the assembly error that exists between the optical reading section and the document table when reading the document. This can be absorbed by correcting the starting position.

[0006]

【Example】 Examples of this invention will be described below with reference to FIGS. 1 to 5. Figure 1 2 is a schematic perspective view showing an embodiment of the image reading device of this invention, and FIG. The schematic circuit configuration diagram of the image reading device shown in FIG. 3 is a part of the document table shown in FIG. The enlarged view, FIG. 4, is a flowchart for explaining the correction operation by the CPU shown in FIG. It is a chart.

[0007] The image reading device 11 shown in FIG. Markers 12 are provided along the direction. The marker 12 is strip-shaped and colored black. Its left end is strictly parallel to the edge line of the document table 2. This marker 12 can be read by the marker detection unit 13 integrated into the optical reading unit 4. 3, and the marker detection unit 13 detects the image shown in FIG. As shown, the distance Xn from the reference line Lr to the left end of the marker 12 is defined as the marker position. to detect. However, n is an integer indicating the line number.

[0008] As shown in FIG. 2, the marker detection unit 13 controls the entire image reading device 11. It is connected to the CPU 14 that controls the optical reading section 4 and its feeding mechanism 15 or Peripheral devices such as the memory 16 and external interface section 17 also perform marker detection. Like the section 13, it is connected to the CPU 14. The CPU 14 uses markers each time the main scan is performed. The marker position detected by the detection unit 13 is detected along with the previous main scan. The resulting comparison error is used to improve the reading speed associated with main scanning. Correct the starting position and set the boundary line Lb at a certain distance Y from the marker 12. control so that reading always starts from

[0009] When reading a document by placing it on the document table 2, first follow the steps in Figure 4. As shown in step (101), the marker 12 located outside the document reading range of the document table 2 The marker detection unit 13 detects the position of the marker 12 from the reference line Lr. The distance to the left end is stored in the memory 16 as the distance X1. Next, in step (102) As shown, the image can be read from the point X1+Y, which is the distance X1 plus the specified value Y. The scanning section 4 starts reading, and one line of image data is captured. like this After reading the first line, in step (103), optical reading is performed. The scraping section 4 is moved together with the marker detection section 13 by one line in the sub-scanning direction.

0010 For the second line as well, before starting to read the second line, read the original on the original platen 2. The marker detection unit 13 detects the marker 12 that is outside the range, and the process proceeds to step (104). As shown, the marker position is defined as the distance X2 from the reference line Lr to the left end of the marker 12. and stores it in the memory 16. Next, in step (105), from the distance The distance X1 obtained last time is subtracted to calculate the difference X2-X1. thus obtained The difference X2-X1 is the assembly error between the document table 2 and the optical reading section 4, in other words. For example, it shows the error D of the reference line Lr with respect to the boundary line Lb. Here, from next time It is used repeatedly to correct the reading start position when reading at low speeds. However, the For line 2, since X2-D matches X1, step (107) is performed. Then, reading the second line from the position X2-D+Y means main scanning. It is possible to read from the exact same position X1+Y as the first line along the direction. means.

[0011] Thereafter, reading from the third line onwards is performed in the same way, but in step (109) When reading the third and subsequent lines, for example, the nth line, there is an error due to the distance Xn. Optical reading is performed by subtracting the difference D (=X2-X1) and adding the specified value Y. The reading start position of section 4 is determined. Therefore, the error obtained from the first two lines is Using this information, the reading start position is corrected up to the last line. 3rd la The distance Xn (n≧3) obtained after in is strictly speaking not included in the comparison, but is simply It is concerned only with the calculation of Xn-X2+X1+Y, which simply determines the reading start position.

0012 In this way, according to the image reading device 11, if the document is outside the document reading range of the document table 2, A marker 12 is provided along the sub-scanning direction, and prior to the main scanning by the optical reading section 4. That is, the position of the marker 12 along the main scanning direction is determined from the main scanning start point (reference line Lr). At the same time as detecting the distance The first two lines are compared, including the marker positions detected along with the main scans up to The reading start position associated with main scanning is corrected using the comparison error D obtained from the scan. child Due to this, reading is always started from a position that is a certain distance from marker 12. It can be controlled so that Therefore, there is a The existing assembly error can be absorbed by correcting the reading start position when reading the document. can be collected. Therefore, even if the document table 2 is slightly different from the optical reading section 4, Even if the optical reading section 4 is assembled with The reading start position in the scanning direction can be corrected. This makes the image information visible. Even fully-filled documents can be read completely without any omissions. Ru. In addition, there is a certain amount of margin of error in the assembly accuracy between the document table 2 and the optical reading section 4. This allows the assembly process to be simplified, while keeping manufacturing costs down. It is also possible to achieve high reading accuracy.

[0013] In addition, in the above example, the data obtained from the first two lines of the first line and the second line are Calculate the error D using the distances X1 and X2, and use this error D to calculate the distance from the third line onwards. The configuration is such that the reading start position is corrected. However, step (201) in Figure 5 As shown below, for the first line and the second line, X1+Y, Even if you start reading from position X2+Y, for the third line, the second Reading start position with error D2 (=X2-X1) between the line and the first line may be modified. In other words, the reading start position of the third line is It is determined as 3-D2+Y, that is, X3-X2+X1+Y. On the 4th line If so, read with the error D3 (=X3-X1) between the 3rd line and the 1st line. To correct the reading start position, reading starts from the position X4-X3+X1+Y. Begins. Similarly, for the nth line, set Xn-X(n-1)+X1+Y. Then, the reading start position of the optical reading section 4 is determined. For this reason, the above embodiment The method shown in Figure 2 fixes the error D using the information obtained from X2-X1 and the first two lines. On the other hand, in this modification, the previous scan line X(n-1) and the first scan line The reading start position of the nth line is determined based on the error D(n-1) generated between Fix it. For this reason, there is a negative Although there is some burden, the precision of the correction is limited because it uses error information about the immediately preceding scan line. The degree will be extremely high.

[0014]

[Effect of the idea]

As explained above, this idea allows the document to be placed outside the document reading range of the document table in the sub-scanning direction. A marker is provided along the main scanning direction, and prior to main scanning by the optical reading section, The position of the marker along the line is detected as the distance from the main scanning start point, and the main scanning This marker position detected each time is compared to the marker position detected during the previous main scan. The reading start position is corrected according to the comparison error obtained. By doing this, you can control the reading to always start from a position that is a certain distance from the marker. Because the configuration is designed to eliminate assembly errors between the optical reading section and the document table, the document This can be absorbed by correcting the reading start position during reading, and therefore the temporary Even if the original platen is installed slightly offset from the optical reading section, the original Correct the reading start position of the optical reading unit in the main scanning direction to match the manuscript table. As a result, even if the document is filled with image information, some parts may be omitted. It can be read completely without any problems. Also, the assembly between the document table and the optical reading section Since there is a certain margin of error in attachment accuracy, it is possible to simplify the assembly process. It has advantages such as being able to achieve high reading accuracy while keeping manufacturing costs down. It has a great effect.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of an image reading device of this invention.

FIG. 2 is a schematic circuit diagram of the image reading device shown in FIG. 1;

FIG. 3 is a partially enlarged view of the document table shown in FIG. 1;

FIG. 4 is a flowchart for explaining a correction operation by the CPU shown in FIG. 2;

FIG. 5 is a flowchart for explaining the correction operation of the CPU shown in FIG. 2 by another method.

FIG. 6 is a schematic perspective view showing an example of a conventional image reading device.

[Explanation of symbols]

2 Document table 3 Device body 4 Optical reading section 11 Image reading device 12 Marker 14 Control means (CPU)

Claims (1)

[Scope of utility model registration request] Claims: 1. An image reading device that reads two-dimensional image information from a document placed on a document table while repeating main scanning and sub-scanning by an optical reading section, wherein a sub-scan is performed outside the document reading range of the document table. a marker provided along the main scanning direction; a marker detection section that detects the position of the marker along the main scanning direction as a distance from the main scanning start point prior to main scanning by the optical reading section; The marker position detected by the marker detection unit is compared, including the marker position detected in the previous main scan, and the reading start position is corrected according to the obtained comparison error, so that the reading start position is always at a constant distance from the marker. 1. An image reading device comprising: control means for controlling reading to start from a position.