JPH0983777A - Document reading method and read position setting method of image reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an accurate, noise-free read image and easily set a read start position at a free position. SOLUTION: When the read start position is set, an adjustment form 1 which is entirely white is read prior to a read of an adjustment form 2 given position marks 3, and the start position and end position of a part which is not white are detected in a horizontal scanning direction and a vertical scanning direction and stored in a nonvolatile memory. When a document is read, white dummy data are sent to the area between the start position and end position to replace the read data. When the read start position is set, the adjustment form 2 given the position marks 3 is read after a read of the white adjustment form 1, and based on the read signal of an area exceeding the stored end position as to the read signal, the read start position is sets. Shadows formed at the frame edge of an original platen and the edge of the document are erased and the read start position can freely be set by displacing and setting the adjustment form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flatbed type and automatic document feeding (ADF) type image reading apparatus, a method for setting an image reading start position in the main scanning direction and the sub scanning direction, and an original used with the method. The present invention relates to a reading method.

[0002]

2. Description of the Related Art An image reading apparatus is provided with a photoelectric conversion element such as a CCD and reads an original by forming an image on the original surface on the light receiving surface of the photoelectric conversion element. The image reading device used as an office machine is equipped with a one-dimensional image sensor (CCD). In the flatbed type, the image sensor side is driven to
In the DF type, a document is run to perform sub-scanning to read two-dimensional image information on the document surface. In any of these structures, there is a difference in the shape of the parts between the fixed position or the passing position of the document and the mounting position of the CCD in the apparatus, the assembly error, and the mounting position error of the parts such as lenses forming the optical system. , A relative position error occurs. Then, such an error appears as an error unique to each apparatus at the document reading position in the main scanning direction and the sub scanning direction.

The presence of such an error hinders the accurate reading of the original document. Therefore, when the assembly of each device is completed, the reading position is measured for each device and the reading is started for each device. You have to set the position. For this setting, for example, in which position of the light receiving cells of the image sensor the reading is started in the main scanning direction, and in the sub-scanning direction the reading unit is moved after the reading unit is moved in the flat bed type. Alternatively, in the case of the ADF type, it is carried out by storing, as an electrical set value, a non-volatile memory such as an EEPROM as to how much the original should be fed after the detection of the leading edge of the original before starting reading.

The setting of the reading position is performed by using the adjusting sheet 2 having the position marks 3 at the four corners of the reading area.
For example, in the case of a flat bed type device, as shown in FIG. 10, the reading operation is performed by aligning the corners of the adjustment sheet 2 with the reference corners 22 of the glass plate 21 serving as a document table.
The reading start position is automatically set based on the position where the image sensor actually reads the position mark 3. Normally, in both the main scanning direction and the sub scanning direction, the reading operation is set to be started slightly before the position where the position mark 3 is read. Shifting the reading start position to the front side is called offset, and is set as shown in A (sub scanning direction) and B (main scanning direction) in FIG.

In the flat bed type apparatus, the back side of the frame 23 around the glass plate 21 is white, and the ADF is used.
In the apparatus of the type, the backside pressing portion of the document at the reading position is made white, the position mark 3 of the adjusting paper 2 is provided in black, and when the image sensor first detects a black color having a predetermined density or more, this is changed. A method is adopted in which the reading start position is automatically set by processing as a position mark detection signal.

[0006]

In order to automatically set the reading start position by the above method, when the adjustment sheet 2 is read, the edge of the sheet abutted against the frame edge of the document table is read. A shadow 15 as shown in FIG. 11 is produced in the portion. Since the position mark 3 of the adjustment sheet is usually provided so as to indicate the edge of the sheet, even if such a shadow occurs, the standard reading start position setting operation is not hindered. But such a shadow 1
Since No. 5 occurs even when a normal document is read, it becomes a noise signal and interferes with accurate reading of the document.

Further, there is a demand for setting the reading position at a position slightly displaced from the standard reading position. This occurs, for example, when a facsimile transmission mark or the like is placed on one side of an original and it is not desired to read it. In such a case, the adjustment sheet 2 is set at the shifted position to set the reading position, or the adjustment sheet provided at the position where the position mark 3 is shifted is used to set the reading position. In this case, since the end of the position mark 3 is displaced from the frame edge of the document table,
There is a gap corresponding to the amount of shift between the shadow 15 in FIG. 11 and the position where the position mark 3 is read. In such a case, if the shadow 15 has a density that can be recognized as a position mark, the apparatus sets the reading start position with the detection position of the shadow 15 as a reference even if the position mark 3 is displaced. Therefore, there arises a problem that the reading position cannot be shifted.

According to the present invention, a more accurate and noise-free read image is obtained by not incorporating the shadow 15 of the frame edge of the platen or the edge of the paper as shown in FIG. 11 at the time of reading the original. The first object is to obtain the second position, and it is possible to set the reading position to a free position by not erroneously recognizing the shadow 15 when setting the reading start position. It is an issue.

[0009]

According to another aspect of the present invention, there is provided a method of reading an original in an image reading apparatus, wherein when the reading start position of the image reading apparatus is set, the adjustment sheet 2 having a position mark 3 is read. The entire white adjustment sheet 1 is set at a standard document setting position and a reading operation is performed, and the start position and the end position of the non-white portion 15 read by the reading operation are set in the main scanning direction and the sub scanning direction. It is detected and stored in the non-volatile memory, and when the original is read, white dummy data is sent to the area between the stored start position and end position, and the read data in the area is replaced to replace the original dummy frame. The feature is that the shadow of the edge or the edge of the document sheet is prevented from being read as the read data.

According to a second aspect of the present invention, there is provided a method for setting a reading position in an image reading apparatus, wherein when the reading starting position of the image reading apparatus is set, the adjustment white sheet for adjusting the entire white color is read before reading the adjustment sheet 2 with the position mark 3. Non-volatile by detecting the start position and the end position of the non-white portion 15 read by the reading operation with the paper 1 set at the standard document setting position in the main scanning direction and the sub scanning direction. The adjustment sheets 4, 8, 11, 12 which are stored in the memory and then have the position mark 3 are read, and the read start position is read based on the read signal of the area of the read signals that exceeds the stored end position. Is set.

[0011]

As described above, as a standard, the reading start position is set slightly before the position where the frame edge of the document table is located. Therefore, when the shadow 15 is generated on the frame edge of the document table, the shadow is recognized as an image signal in the reading area and becomes a dirt or noise signal of the read image. According to the first aspect of the invention, the shadow 15 formed on the frame edge of the document table or the edge of the document at the standard position is detected when the white adjustment sheet 1 is read and stored in the non-volatile memory, and the document is read. Since the portion of the shadow 15 is sometimes replaced with white dummy data, the data of the shadow 15 at the frame edge of the platen is erased, and an accurate and noise-free read image is obtained.

According to the invention of claim 2, among the read signals of the adjustment sheets 1 and 2 with the position mark 3, the read signal of the area after the shadow 15 generated at the frame edge portion of the document table is used. Since the reading start position is set, the reading start position is not set by the signal of the shadow 15, and the adjustment sheets 4 and 8 having the position mark 3 at a position distant from the edge of the sheet,
By using 11 and 12, the desired displaced reading start position is automatically set without error.

[0013]

1 to 6 are views showing an embodiment of the present invention. FIG. 1 shows a white adjustment sheet 1.
Is a white paper of a size (for example, A4) corresponding to the size of the reading area to be set. FIG.
Is a diagram showing a standard adjustment sheet 2, in which black position marks 3 are provided at four corners of a white sheet having a size (for example, A4) corresponding to the reading area to be set.

3 and 4 show special adjustment sheets 4 and 8 used when displacing the reading start position in the sub-scanning direction.
The protrusion 6 having a width (width corresponding to the number of read dots a to be displaced) corresponding to the dimension to be displaced is provided on one of the short sides 5 of the standard adjustment sheet 2 shown in FIG. . FIG.
3 is a special adjustment sheet 8 in which a negative mark 7 is provided at the center of the side 5 on which the projection 6 of the special adjustment sheet 4 of FIG. 3 is provided.
This is an adjustment sheet used when the reading start position is displaced to the minus side by the width of.

5 and 6 show special adjustment sheets 11 and 1 used when displacing the reading start position in the main scanning direction.
In FIG. 2, a white tape 13 having a width corresponding to a dimension to be displaced along one long side 9 of the standard adjustment sheet 2 in FIG. is there. In FIG. 6, a negative mark 7 similar to that in FIG. 4 is provided on the special adjustment sheet of FIG. 5 so that the reading start position is displaced to the minus side.

The special adjustment sheets 4 and 8 in the sub-scanning direction are provided with protrusions 6 on their short sides 5, and the special adjustment sheets 11 and 12 in the main scanning direction are provided with white tape on one long side 9. 13 is attached to prevent the paper width from being widened. These special adjustment sheets are used not only for the flatbed-type image reading device but also for setting the reading start position of the ADF-type image reading device. This is so that it can be used. Therefore, the protrusion 6 of the special adjustment sheet of FIG. 3 and FIG.
Must be provided at the position where the document leading edge detection sensor of the ADF type device is arranged.

Such adjustment sheets 1, 2, 4, 8, 1
The method of the present invention, which is carried out by using Nos. 1 and 12, is shown in the flow charts of FIGS.

In the flowchart of FIG. 7, when the automatic adjustment operation for setting the reading start position is started, the shadow 15 of the frame edge is displayed.
It is determined whether or not a portion (in the flat-bed type image reading device, it appears at the boundary between the frame plate and the glass surface) has been measured. This determination can be made based on whether or not the shadow portion data is stored in a non-volatile memory such as an EEPROM. If the measurement has been completed, the process moves to automatic adjustment (adjustment operation according to the flowchart of FIG. 8) according to each adjustment sheet.

When the shadow 15 portion is not measured, the measurement operation of the shadow 15 portion (FIG. 11) is started. First, it is determined whether or not the adjustment sheet is white adjustment sheet 1, and if it is white adjustment sheet 1, the adjustment sheet is read and the start position and end position of the non-white portion are set in the main scanning and sub-scanning directions. Both are measured and stored in a non-volatile memory such as an EEPROM. When the set adjustment paper is not a white adjustment paper, it is determined that the shadow portion is not measured, and the reading start position is set by the method that has been conventionally used.

FIG. 8 shows a case where a white adjustment sheet 1 is used to shade 15
Adjustment papers 4, 8, 11, 1 after scanning the part
6 is a flowchart showing a procedure for setting a reading start position by No. 2.

In this case, the adjustment sheet is read by starting to take in the image data from the end position of the shadow portion 15 stored when the white adjustment sheet 1 is read. Then, when the position mark 3 of the adjustment sheet is read with a dot delay from the end position of the shadow 15 in the sub-scanning direction, it is determined whether or not the negative sheet 7 is attached to the adjustment sheet. , The reading start position is set by correcting the offset in the sub-scanning direction by a dots smaller than the standard value. If a negative mark 7 is attached to the side of the sheet, the offset in the sub-scanning direction is corrected by a dot larger than the standard value and the reading start position is set. The offset (A and B in FIG. 12) is an amount by which the reading start position is shifted from the reading position of the position mark 3 to the front side, and correcting the offset small means delaying the reading start position. Then, the reading start position in the sub-scanning direction set in this way is stored in a non-volatile memory such as an EEPROM.

Similarly in the main scanning direction, when the position mark 3 of the adjusting sheet is detected a dot behind the position where the shadow 15 appears, whether the negative mark 7 is attached to the center of the side of the sheet is determined. If not, the offset in the main scanning direction is corrected by a dot smaller than the standard value to set the reading start position. If there is a negative mark 7, the offset in the main scanning direction is corrected by a dot larger than the standard value and the reading start position is set. Then, the set value is stored in a nonvolatile memory such as an EEPROM, and the automatic adjustment work of the reading start position is completed.

FIG. 9 is a flow chart showing a procedure for reading an original according to the present invention. When the document is read, it is determined whether or not the shadow 15 is read using the white adjustment sheet 1. If not, the read data is directly read as in the conventional method. Data. If the shadow 15 portion is measured, the data in the area corresponding to the shadow portion of the read data is replaced with white data to obtain read image data.

[0024]

According to the method of the present invention described above,
When a manuscript is read, it is possible to obtain image data without such a shadow when a black shadow is read on the frame edge of the manuscript table or the edge of the paper as shown in FIG. it can. In addition, as a reading area of a document, the conventional reading area shown in FIG.
As shown in FIG. 3, the offsets A and B in the sub-scanning and main-scanning directions of the paper are fixed, but the width can be set to an arbitrary width including a minus width, and special adjustment as shown in FIGS. The use of the use paper has an effect that the reading start position can be automatically set to a free position.

[Brief description of drawings]

FIG. 1 is a plan view of a white adjusting paper.

FIG. 2 is a plan view of a standard adjusting sheet.

FIG. 3 is a plan view of an adjustment sheet for displacing the reading start position in the sub-scanning direction.

FIG. 4 is a plan view of an adjustment sheet for displacing the reading start position in the sub-scanning direction to the negative side.

FIG. 5 is a plan view of an adjustment sheet for displacing the reading start position in the main scanning direction.

FIG. 6 is a plan view of an adjustment sheet for displacing the reading start position in the main scanning direction to the negative side.

FIG. 7 is a flowchart showing a first stage of a reading position setting method.

FIG. 8 is a flowchart showing a second step of the reading position setting method.

FIG. 9 is a flowchart showing a document reading method.

FIG. 10 is a plan view showing the relationship between a document table and adjustment sheets.

FIG. 11 is a diagram showing a shadow of a read image.

FIG. 12 is a diagram showing an offset of a reading start position.

[Explanation of symbols]

 1 White adjustment paper 2 Standard adjustment paper 3 Position mark 4 Special adjustment paper 8 Special adjustment paper 11 Special adjustment paper 12 Special adjustment paper 15 Shadow

Claims (2)

[Claims] 1. When setting the reading start position of the image reading device, prior to reading the adjustment sheet (2) with the position mark (3), the entire white adjustment sheet (1) is set as a standard document. Set the position and perform the reading operation, detect the start position and the end position of the non-white part (15) read by the reading operation in the main scanning direction and the sub scanning direction and store them in the non-volatile memory. At the time of reading, by sending white dummy data to the area between the stored start position and end position and replacing it with the read data in the area, the shadow of the frame edge of the document table or the edge of the document paper is read data. A method of reading an original in an image reading apparatus, characterized in that it is prevented from being read as. 2. When setting the reading start position of the image reading device, prior to reading the adjustment sheet (2) with the position mark (3), the entire white adjustment sheet (1) is set as a standard document. Set the position and perform the reading operation, and detect the start position and the end position of the non-white portion (15) read by the reading operation in the main scanning direction and the sub scanning direction and store them in the non-volatile memory. Read the adjustment sheet (4,8,11,12) with the position mark (3) on it, and set the read start position based on the read signal of the area of the read signal that exceeds the stored end position. A reading position setting method in an image reading apparatus, comprising: