JP2006109408A - Image reading apparatus, method of adjusting the same and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimally synthesize images by easily measuring deviation amount of an image in a sub-scanning direction at a reading joint of reading sensors in a short period of time, and highly accurately obtaining the delay amount of image data read by a first reading sensor in an upstream with respect to image data read by a second reading sensor in a downstream. <P>SOLUTION: Respective differences are found which are calculated by causing the plurality of reading means to read an original document having a plurality of reference straight line patterns extending in a main scanning direction, and which are caused in such a way that a plurality of straight line images extending in a main scanning direction at a reading joint between a first reading means and a second reading means are displaced in a sub scanning direction. A value acquired by applying arithmetic mean to the differences is used as a mean value of the relative deviation amount. The mean value of the relative deviation value is determined as the delay amount of the image data read by the first reading means, and is set as a correction value for correcting the deviation value. The delay time of the first reading means in the compositing means is adjusted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for adjusting an image reading apparatus, an image reading apparatus using the same, and an image forming apparatus in an image forming apparatus such as a copying machine, a facsimile, or a printer that forms an image using an electrophotographic method or an inkjet method.

Hereinafter, the conventional technique will be described with reference to FIGS.
FIG. 1 is a schematic configuration diagram of a conventional image reading apparatus. The image reading apparatus recognizes that the original 11 has been inserted by the first paper detection 9 at the leading edge of the original 11 inserted from the original table 8, rotates the first conveying roller 1 and the second conveying roller 2, and The reading start timing is taken by the second paper detection 10. The image of the document 11 guided to the reading sensor 3 by the rotation of the first conveying roller 1 is read by the reading sensor 3, and the document 11 that has been read is discharged out of the machine by the second conveying roller 2.
Illumination means 5 is provided inside the reading sensor 3, and a predetermined amount of light is applied to the image surface of the document 11, and reflected light corresponding to the image pattern reflected from the image surface passes through the SELFOC lens 6. Thus, an image is formed on the light receiving element 7 at the same magnification. The analog output level of the light receiving element 7 corresponding to the image of the document 11 is converted from analog to digital value by the A / D conversion circuit, and the converted data is stored in the memory as image data.

FIG. 2 is a diagram illustrating types 1 to 3 of a conventional reading sensor. Conventional reading sensor reading methods are roughly classified into types 1 to 3. Type 1 in FIG. 2 (a) is a method of reading by one reading sensor 3-a having a length that can correspond to the maximum width of the document. Type 2 in FIG. This is a method of arranging a plurality of read sensors 3-b in the width direction and synthesizing the read images (see, for example, Patent Document 1). Type 3 in FIG. The type 2 is a reading sensor using an equal-magnification type imaging element, and the type 3 is a method using a reduction type reading sensor 3-c using a reduction lens 12. It is.
The advantage of Type 1 is that a high-quality image can be obtained with a simple configuration, but the disadvantage is that one reading sensor 3-a used in this method can handle any size in the width direction of the document. It must be. Since the parts cost of the reading sensor is proportional to the length of the document in the width direction, for example, when reading an A0 width document, an A0 length sensor is required, and the parts cost of the reading sensor increases, resulting in the apparatus being The disadvantage of Type 1 is that the cost of itself increases.
Type 2 is a method devised to compensate for the drawbacks of Type 1. The merit of Type 2 is that the parts cost of the reading sensor can be reduced by arranging a plurality of reading sensors 3-b with a short width, but the disadvantage is that the images read by the plurality of sensors are synthesized. Therefore, the image data processing becomes complicated.
The advantage of Type 3 is that the parts cost of the read sensor can be reduced in the same way as Type 2. However, in order to further reduce the cost compared to the Type 2 sensor, a reduced type read sensor 3-c is used. There is in point.

Here, as a specific type 2 image reading method, first, a part of the image in the width direction is read by a reading sensor arranged on the upstream side in the document conveying direction, and then arranged on the downstream side thereof. An image area that has not yet been read by the reading sensor is read. At this time, the image data read by the upstream reading sensor is temporarily stored in a predetermined memory and delayed, and is combined with the image data read by the downstream reading sensor.
As described above, in Type 2, since it is necessary to combine images read by a plurality of sensors, the position accuracy of the reading sensor is increased so that the images are normally connected at the reading joint of the reading sensor dividing unit when the images are combined. In addition to obtaining the relative distance in the sub-scanning direction of the upstream and downstream reading sensors, the image data read by the upstream reading sensor is delayed by an amount corresponding to the relative distance, and the downstream reading sensor A correction operation for combining the image data read in step 1 with the image data is required.

Here, as a conventional correction operation method,
(1) A method in which the relative distance in the sub-scanning direction of the reading joints of the upstream and downstream reading sensors is mechanically measured and converted into a correction value, and the delay amount of the image data read on the upstream side is set.
(2) A monitor that displays the read image is connected to the type 2 image reading apparatus, and a single straight line extending in the main scanning direction is read and displayed on the monitor. A method of measuring the relative shift amount in the sub-scanning direction at the reading joint of the upstream and downstream reading sensors, converting it to a correction value, and setting the delay amount of the image data read on the upstream side.
(3) Further, as in Patent Document 2, each straight line extending in the main scanning direction is read by each reading sensor, and each regression is performed by a control circuit configured by a CPU or the like based on pixel data of the straight line image. A method of automatically obtaining a straight line, obtaining a relative shift amount in the sub-scanning direction of the reading joint of each reading sensor, and setting a delay amount of image data (see, for example, Patent Document 2).

However, in the conventional setting methods (1) and (2), it takes time and labor to measure the shift amount of the reading joint of the upstream and downstream reading sensors, and there is a problem that the manufacturing cost increases. In addition, there is a possibility that an accurate setting cannot be performed due to variations in measurement results due to the discretion of the operator, and accurate adjustment cannot be performed.
In the method (3), since the measurement of one sub-scanning direction and the setting of the correction value can be automatically performed by the CPU or the like, the problems (1) and (2) are reduced. However, there is no problem when the distance between the upstream and downstream reading sensors in the sub-scanning direction is small, but generally the width of the general-purpose reading sensor in the sub-scanning direction is equal to the width of the substrate on which the light receiving element is mounted and the housing. A width is required. For this reason, when the reading sensors are arranged in a staggered manner, the distance L (deviation amount) in the sub-scanning direction between the upstream and downstream reading sensors shown in FIG. 4 increases.

Accordingly, when the original is conveyed in the sub-scanning direction and an image is read, a shift in the conveyance speed between the distances in the sub-scanning direction between the upstream and downstream reading sensors cannot be ignored. If a single straight line extending in the main scanning direction is read as in the method (3) and the delay amount is determined based on the pixel data of the straight line image, the sub-scanning between the upstream and downstream reading sensors is performed. When the delay amount is set based on the read image that is largely different from the target conveyance speed due to the deviation of the document conveyance speed between the distances in the direction, for example, as shown in FIG. An image shift occurs in most of the straight line images that are read and combined as output.
FIG. 3 is a diagram showing an image shift at the reading joint of the reading sensor caused by a shift in the document conveyance speed. A linear image in which no image deviation occurs is a portion where there is no deviation at the moment of reading at the same conveyance speed as the original conveyance speed at the time of image reading with a delay amount set.

Furthermore, an image shift occurs in the reading connection portion also in the following cases.
In other words, the conveyance roller used in the reading apparatus normally has a diameter of the second conveyance roller on the downstream side slightly larger than the diameter of the first conveyance roller on the upstream side so that wrinkles do not occur when the document is conveyed. For example, the document surface is always conveyed by the pulling effect of the second conveyance roller on the downstream side. At this time, there is a difference in the document conveyance speed before and after the document is added to the second conveyance roller on the downstream side. Therefore, for example, the image data read by the first reading sensor on the upstream side and the image read by the second reading sensor on the downstream side are synthesized in accordance with the conveyance speed of the second conveyance roller on the downstream side. When the delay amount is set, the image before the document is fed to the downstream second transport roller is slower than the document transport speed by the downstream second transport roller. As shown in FIG. 9, the connecting portion causes an image shift such that an image read by the first reading sensor on the upstream side in the sub-scanning direction precedes the document conveyance direction.

JP 59-105762 A JP-A-8-97980

  The present invention has been made in view of the above-mentioned problems, and can easily measure the amount of deviation in the sub-scanning direction of an image at a reading joint of a reading sensor in a short time, and the measurement result varies depending on the discretion of the operator. Of the image reading apparatus that accurately obtains the delay amount of the image data read by the first reading sensor on the upstream side with respect to the image data read by the second reading sensor on the downstream side and optimally combines the images. It is an object of the present invention to provide an adjustment method, an image reading apparatus using the adjustment method, and an image forming apparatus.

As means for solving the above problems, the present invention has the following features.
An adjustment method for an image reading apparatus according to the present invention includes a first transport roller that transports a document inserted from a document insertion slot to a reading unit, a detection unit that detects the transported document, and a first transport roller. A plurality of reading means for reading the conveyed document, and the plurality of reading means are arranged in a row in the longitudinal direction along a predetermined line in the main scanning direction, and the first reading means on the upstream side and the first reading means on the downstream side. Each of the reading means is sub-scanned so that a plurality of reading start pixels and reading end pixels of the image data at the reading joint of the first reading means and the second reading means overlap each other. The image data read by the first reading means among the plurality of reading means arranged in a zigzag pattern are alternately allocated in the direction. A second image forming unit that combines the image read by the second reading unit with the second reading unit; a second conveying roller that guides and conveys the document that has been read in a direction opposite to the insertion port; In the method for adjusting the plurality of reading means in the image reading apparatus comprising a driving means for rotationally driving the conveying rollers and a control means for controlling the rotational driving of the first and second conveying rollers, the adjusting method comprises: Extending in the main scanning direction at the reading joint between the first reading means and the second reading means calculated by causing the plurality of reading means to read a document having a plurality of reference linear patterns extending in the main scanning direction. Each of the differences between the plurality of linear images in the sub-scanning direction is obtained, and the arithmetic average value is used as the average value of the relative shift amounts, thereby calculating the average value of the relative shift amounts in the first reading. Ri is determined as the delay amount of the image data read by means, characterized in that adjusting the delay time of the first reading means in said combining means.
In this way, at the reading joint between the reading means of the first reading means and the second reading means calculated by causing the plurality of reading means to read a document having a plurality of reference linear patterns extending in the main scanning direction. By determining the difference between the multiple linear images extending in the main scanning direction in the sub-scanning direction, it is possible to easily measure the amount of image shift at the reading joint of the reading sensor in a short time. The variation due to the discretion of the operator is eliminated, and the delay amount of each linear image is accurately obtained, and the image is optimally combined.

The image reading apparatus adjusting method according to the present invention includes a plurality of linear patterns extending in the main scanning direction within a range of the sub-scanning distance from the leading edge of the document to the second conveying roller and the first reading means. The original document arranged and read by a plurality of originals within a range upstream from the sub-scanning distance from the leading edge of the original document to the second transport roller and the first reading means, and held by the storage means The sub-scanning direction calculated from each linear pattern image data at the reading joint between the first reading means and the second reading means within the range of the distance between the second conveying roller and the first reading means from the front end. And the first reader in the range upstream of the distance between the second transport roller and the first reading means from the leading edge of the original to the sub-scanning distance. And the average value of the relative shift amounts in the sub-scanning direction calculated from the linear pattern image data at the reading joint of the second reading means, respectively, thereby obtaining the original by the first and second transport rollers. The rotational drive of the first and second transport rollers is adjusted and controlled so that the transport speed of the first and second transport rollers is constant.
As described above, the delay amount which is an average value of the relative shift amount in the sub-scanning direction at the reading joint within the range of the sub-scanning distance between the second conveying roller at the leading end of the document and the first reading unit, By calculating the difference in delay amount at the reading joint within the range upstream of the sub-scanning distance at the leading edge of the document, the control means for controlling the rotational driving of the first and second transport rollers is automatically used as the acceleration amount. And the document transport speed is always kept constant.

Further, the adjustment method of the image reading apparatus according to the present invention uses the center of gravity method for the Y coordinate of each linear image extending in the main scanning direction when the main scanning direction is the X coordinate and the sub scanning direction is the Y coordinate. It is characterized by calculating.
Recognition of the straight line to be evaluated is performed in two steps: “threshold search” using the pixel level and “centroid search” using the centroid method. A coordinate group recognized as a straight line by threshold discrimination is obtained, and the coordinates (center of gravity) of the straight line to be evaluated are obtained by calculation. One straight line is formed of several pixels in the X direction and the Y direction, and causes a reading density difference for each pixel. Therefore, the Y coordinate of the straight line can be accurately obtained by using the centroid method.

  The image reading apparatus of the present invention is characterized by using the above-described adjustment method.

  The image forming apparatus of the present invention is an electrophotographic or inkjet image forming apparatus that forms an image corresponding to an image information signal read by the image reading apparatus, and the image forming apparatus includes the above-described image reading apparatus. A device is provided.

  According to the means for solving the above-described problems, according to the adjustment method of the present invention, the measurement and adjustment of the deviation amount of the image in the sub-scanning direction can be performed in a short time at the reading joint of each reading means without depending on the discretion of the operator. So that the delay amount of the image data read by the upstream first reading sensor with respect to the image data read by the second reading sensor on the downstream side can be obtained accurately and the image can be optimally combined. In addition, automatic adjustment can be performed so that the document conveyance speed is always kept constant, and a high-quality image free from image displacement due to overlapping or missing pixels can be obtained. As described above, the present invention can provide a method for adjusting an image reading apparatus with improved convenience, an image reading apparatus using the same, and an image forming apparatus.

  Below, the best form for implementing this invention is demonstrated based on FIGS. However, these are merely embodiments, and do not limit the scope of the claims of the present invention.

  4A and 4B are schematic views of the image reading apparatus according to the present invention as viewed from the upper surface and the side surface. FIG. 4A is a schematic view as viewed from the upper surface, and FIG. 4B is a schematic diagram as viewed from the side surface. is there. The image of the document 11 conveyed between the contact glass 4 and the pressure plate 13 by the first conveying roller 1 is read by the upstream first reading sensors 3-1 and 3-3 and the downstream second reading sensor 3-2. The paper is discharged by the second transport roller 2. As shown in FIG. 5, the image data read by the first reading sensors 3-1, 3-3 is converted into digital signals (256 gradations) by the A / D conversion circuit. The number of lines (distance / distance) corresponding to the relative distance (shift amount) in the sub-scanning direction at the joint of the first reading sensors 3-1 and 3-2 and the second reading sensor 3-2 is converted by the next delay circuit. (Reading density) is delayed and the read image is combined into one line in accordance with the output of the image read by the second reading sensor, and sent to the downstream image processing circuit. Here, L in the drawing is a distance in the sub-scanning direction at a reading joint between the first reading sensors 3-1 and 3-3 and the second reading sensor 3-2, and corresponds to a shift amount in the sub-scanning direction. LL in the drawing is a distance in the sub-scanning direction between the second conveyance roller 2 and the first reading sensors 3-1 and 3-3 from the leading end of the document 11 until the document 11 is held by the second conveyance roller 2. This is a slight image area from the front end of the original to be read.

FIG. 5 is a diagram for explaining an adjustment method of the image reading apparatus.
FIG. 5A is a diagram illustrating a delay amount of image data generated between the upstream first reading sensor and the downstream second reading sensor. The delay amount L corresponds to the amount of deviation in the sub-scanning direction.
FIG. 5B is a block diagram illustrating a method for adjusting the image reading apparatus. In order to obtain the delay amount of the image data read by the first reading sensors 3-1 and 3-3, the delay amount is calculated from the page memory for holding the image read by the image device and the held image data. An adjusting device having a control circuit for determination is connected. The image data read by the first reading sensors 3-1 and 3-3 are converted into 256 gradation digital signals by the A / D conversion circuit, and a plurality of shift amounts L in the sub-scanning direction are respectively obtained by the delay circuit. Delayed by the number of lines corresponding to the average value of the averaged relative shift amounts, combined into one line in accordance with the output of the image read by the second reading sensor, and sent to the downstream image processing circuit. Here, the number of lines is a value obtained by dividing the shift amount L by the reading density.

Hereinafter, as the sub-scanning adjustment method of the present invention, the sub-scanning direction shift correction operation of the first reading sensors 3-1 and 3-2 and the second reading sensor 3-2 will be described with reference to FIGS. .
FIG. 6 is a diagram for explaining a method of recognizing a straight line pattern of a reading joint of the reading sensor in the adjustment method of the present invention. First, a document having a plurality of linear patterns orthogonal to the document conveyance direction (sub-scanning direction) in FIG. Next, the synthesized image is stored in the page memory of the adjusting device, and the control circuit recognizes the linear pattern of the regions a and b shown in FIG.
Next, the Y coordinate at the reading joint of each reading sensor of each recognized linear pattern is obtained as Y1 (n), Y2L (n), Y3 (n), Y2R (n) as shown in FIG. FIG. 7 is a diagram for explaining a method for obtaining the amount of deviation in the sub-scanning direction from the Y coordinate of the reading joint of each linear pattern.
Here, since the read linear pattern has a reading density difference in width and each dot unit in the Y direction as shown in FIG. 8, it is desirable to accurately obtain the Y coordinate of the straight line using the centroid method or the like. FIG. 8 is a diagram for explaining the width existing in the Y direction of the linear pattern and the reading density difference for each dot unit.
The average value R12 of the shift amount in the sub-scanning direction of the first reading sensor 3-1 and the second reading sensor 3-2 is obtained from the Y coordinate obtained as described above by the following equation (1).
R12 = Σ (Y1 (n) −Y2L (n)) / n Expression (1)
The average value R32 of the shift amount in the sub-scanning direction of the first reading sensor 3-3 and the second reading sensor 3-2 is obtained by the following equation (2).
R32 = Σ (Y3 (n) −Y2R (n)) / n (2)
Each of R12 and R32 is determined as a delay amount, and R12 and R32 are set as correction values for correcting the shift amount in the delay circuit from an input device (not shown) of the image reading apparatus.

  R12 and R32 each obtain a difference in which a plurality of linear images are shifted in the sub-scanning direction, and an arithmetic average value is used as an average value of relative shift amounts. For this reason, even when there is uneven conveyance speed between the distances in the first and second reading sensors in the sub-scanning direction, R12 and R32 are in a row because of the delay amount with respect to the deviation in the sub-scanning direction at the averaged conveyance speed. Deviations in the sub-scanning direction at the reading joints of the reading sensors generated in the synthesized image are corrected without deviation.

Further, the reason why the delay amount is determined by using the data of the linear pattern images in the upstream a and b regions apart from the leading edge of the document shown in FIG. 6 is as follows.
The conveying roller used in the reading device is usually configured such that the diameter of the second conveying roller 2 is slightly larger than the diameter of the first conveying roller 1 so that wrinkles do not occur when the document is conveyed. Due to the pulling effect, the document surface is conveyed so that it is always stretched. Since the document 11 is transported only by the first transport roller 1 having a small diameter until the document 11 is gripped by the second transport roller 2, the transport speed until the document 11 is gripped by the second transport roller 2 is It is slower than the conveyance speed after the document 11 is held by the second conveyance roller 2.
Here, as shown in FIG. 4, the image area of the original that is read until the original 11 is held by the second conveying roller 2 is the second conveying roller 2 and the first reading sensors 3-1, 3- 3 is a region having a sub-scanning distance LL. The LL area is a small area at the front end, and if the delay amount is determined using the linear pattern image data of the upstream a and b areas apart from the front end of the document other than the LL area, the area other than the slight area between the front end and LL is determined. Deviation is corrected over a wide range.

FIG. 9 is a diagram illustrating an image shift of the reading joint of the reading sensor due to a difference in conveying speed between the upstream conveying roller and the downstream conveying roller. Since the LL region at the leading edge of the document is conveyed and read by the first conveyance roller 1 that is slower than the conveyance speed of the second conveyance roller 2, the first reading sensors 3-1, 3 and 3 are matched with the conveyance speed by the second conveyance roller 2. When the image data read at -3 and the image read by the second reading sensor 3-2 are combined, the image is read by the first reading sensor in the document feed direction (sub-scanning direction) at the reading joint in the LL area. The image shifts as if the image preceded the conveyance direction.
For example, as shown in FIG. 4, when the diameter of the second transport roller 2 is 30.5 mm, the diameter of the first transport roller 1 is 30 mm, and the sub-scanning interval L between the first and second reading sensors is 30 mm, Since the diameter of the conveying roller 2 is about 0.17% larger, the amount of deviation is about 50 μm, and when read at a resolution of 600 dpi (42.3 μm per pixel), an image deviation of just over one line occurs.

Here, in this embodiment, the first driving pulley 14, the second driving pulley 15, and the timing belt 17 are driven by the stepping motor 16 that can control the rotational speed of the first and second transport rollers by a control means (not shown). , The document 11 is detected by the first paper detection 9, the first and second conveyance rollers are started to rotate, the leading edge of the document is detected by the second paper detection 10, and the second conveyance roller 2 is detected. Until the original 11 is held, the conveyance speed of the original is always kept constant by increasing the conveyance speed so as to be the same as the conveyance speed by the second conveyance roller 2 as shown in FIG. Image misalignment in the sub-scanning direction of the reading joint is prevented.
The speed increase amount is obtained as follows.
First, as shown in FIG. 6, a linear pattern of a document having a plurality of linear patterns orthogonal to the document conveyance direction is added to the second conveyance roller 2 and the first reading sensors 3-1 and 3-3 from the leading edge of the document. A plurality in the range of the inter-scanning distance LL, and a range in the sub-scanning direction upper part away from the sub-scanning distance LL between the second transport roller 2 and the first reading sensors 3-1, 3-3 from the leading edge of the document. Scan multiple documents placed in the document.
Next, the delay amounts R12 and R32, which are the average values of the relative shift amounts of the a and b regions apart from the LL region at the front end of the document obtained by the above formulas (1) and (2), and the LL obtained similarly. From the delay amounts R′12 and R′32 that are the average values of the relative shift amounts of the a ′ and b ′ regions within the region range, the speed increase amount is obtained by the following equation (3) or the following equation (4). It is done.
(R12−R′12) / R12 × 100 (%) (3)
(R32−R′32) / R32 × 100 (%) (4)
This is also set by the input device (not shown) of the image reading apparatus as a speed increase amount in a control means for controlling the rotational drive of the first and second transport rollers (not shown), so that the document transport speed is always constant. For this reason, the shift in the sub-scanning direction of the reading joint of the reading sensor as shown in FIG. 9 can be prevented, and a high-quality image free from image shift due to overlapping or omission of pixels can be obtained in the entire reading joint of each reading sensor. Can do.

Therefore, according to the present invention, since the delay amount of the image data in the sub-scanning direction is automatically set accurately by the adjustment device, it takes time and labor as in the conventional adjustment method, resulting in the manufacture. The cost is not increased, and accurate settings are made without variations that do not depend on the discretion of the operator, and high-quality images without image displacement due to overlapping or missing pixels can be obtained at the reading joints of each reading sensor. Further, it is possible to provide an adjustment method for an image reading apparatus with improved convenience, and an image reading apparatus and an image forming apparatus using the same.

FIG. 10 is a schematic configuration diagram of an image forming apparatus provided with the image reading apparatus of the present invention.
The image reading apparatus 100 includes a first conveyance roller 1 that conveys a document inserted from a document insertion opening to a reading unit 101 in a document conveyance direction A, a reading unit 101 that reads the conveyed document with a plurality of reading sensors, The plurality of reading sensors are composed of a plurality of combinations of an upstream first reading sensor and a downstream second reading sensor, each arranged in a line in the longitudinal direction along a predetermined line in the main scanning direction, Each reading sensor is alternately assigned in the sub-scanning direction so as to overlap a plurality of reading start pixels and reading end pixels of image data at the reading joint of the first reading sensor and the second reading sensor, and arranged in a staggered manner. Among the plurality of reading sensors arranged in a staggered pattern, the image data read by the first reading sensor is delayed. Comprising synthesizing means for synthesizing the image and a line read by the second reading sensor, and a second conveying roller 2 for conveying guided in a direction opposite to the insertion opening a document reading has been completed.
The image forming apparatus includes an image reading apparatus 100 that converts read document information into an electrical image signal, and an image forming unit 103 that forms an image corresponding to the read image signal on an image carrier using a writing unit 102. A developing unit 104 that carries the developer on the surface of the developing roller, transports the developer to a developing region facing the image carrier, and transfers the image to an electrostatic latent image formed on the image carrier, and an image; A fixing unit 105 is provided for fixing the toner image visualized on the carrier to the recording paper.
The image forming apparatus of FIG. 10 is also compatible with A0 size drawing originals, and the roll paper feeding unit 107 can be cut by the cutter 109 according to the length of the A0 size originals and sent as recording paper. The cassette paper feeding unit 108 is compatible with A3 size originals.
Note that the image forming apparatus may be either an electrophotographic system or an inkjet system, and by providing the image reading apparatus using the adjustment method of the present invention, a high-quality image without image displacement can be obtained and convenience can be improved. Can do.

It is a schematic block diagram of the conventional image reading apparatus. It is a figure explaining types 1-3 of the conventional reading sensor. FIG. 6 is a diagram showing image misalignment at a reading joint of a reading sensor caused by a deviation in document conveying speed. 1 is a schematic view of an image reading apparatus according to the present invention as viewed from the top and side surfaces. It is a figure explaining the adjustment method of an image reading apparatus. It is a figure for demonstrating the linear pattern recognition method of the reading joint of the reading sensor in the adjustment method of this invention. It is a figure explaining the method of calculating | requiring the deviation | shift amount of a subscanning direction from the Y coordinate of the reading joint of each linear pattern. It is a figure explaining the width which exists in the Y direction of a linear pattern, and the reading density difference of each dot unit. FIG. 5 is a diagram illustrating image misalignment of a reading joint of a reading sensor caused by a difference in conveying speed between an upstream conveying roller and a downstream conveying roller. 1 is a schematic configuration diagram of an image forming apparatus including an image reading apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st conveyance roller 2 2nd conveyance roller 3-1, 3-3 1st reading sensor 3-2 2nd reading sensor 4 Contact glass 5 Illumination means 6 Selfoc lens 7 Light receiving element 8 Original table 9 First paper detection 10 Second paper detection 11 Document 12 Reduction lens 13 Pressure plate 14, 15 Drive pulley 16 Stepping motor 17 Timing belt 21 Reading line 22 of first reading sensor Reading line 100 of second reading sensor 100 Document conveying section 101 Reading section 102 Writing section 103 Image unit 104 Developing unit 105 Fixing unit 106 Manual feeding unit 107 Roll paper feeding unit 108 Cassette paper feeding unit 109 Cutter A Original conveyance direction

Claims (5)

A first transport roller for transporting a document inserted from a document insertion slot to a reading unit;
Detection means for detecting the conveyed document;
A plurality of reading means for reading the document conveyed by the first conveying roller;
The plurality of reading means is composed of a plurality of combinations of an upstream first reading means and a downstream second reading means arranged in a line in the longitudinal direction along a predetermined line in the main scanning direction, The reading means are alternately allocated in the sub-scanning direction so that a plurality of reading start pixels and reading end pixels of the image data at the reading joint of the first reading means and the second reading means overlap each other, and are arranged in a staggered manner. ,
Among the plurality of reading means arranged in a staggered manner, the combining means for delaying the image data read by the first reading means and combining it with the image read by the second reading means,
A second transport roller for guiding and transporting the document that has been read in a direction opposite to the insertion slot;
Drive means for rotationally driving the first and second transport rollers;
In the method for adjusting the plurality of reading means in an image reading apparatus comprising control means for controlling the rotational drive of the first and second transport rollers,
In the adjustment method, main scanning at a reading joint between the first reading unit and the second reading unit calculated by causing the plurality of reading units to read a document having a plurality of reference linear patterns extending in the main scanning direction. The difference between the plurality of linear images extending in the direction is respectively determined in the sub-scanning direction, and the arithmetic average value is used as the average value of the relative shift amounts, thereby calculating the average value of the relative shift amounts. An adjustment method for an image reading apparatus, characterized in that it is determined as a delay amount of image data read by a first reading means, and a delay time of the first reading means in the synthesizing means is adjusted. In the adjustment method, a plurality of linear patterns extending in the main scanning direction are arranged within the range of the sub-scanning distance from the document leading edge to the second transport roller and the first reading means, and from the document leading edge. A plurality of originals arranged in a range upstream of the sub-scanning distance between the second transport roller and the first reading unit are read and held by a storage unit;
The sub-pattern calculated from each linear pattern image data at the reading joint between the first reading means and the second reading means within the range of the sub-scanning distance from the leading edge of the document to the second conveying roller and the first reading means. The average value of the relative displacement in the scanning direction;
From each linear pattern image data at the reading joint of the first reading means and the second reading means within the range upstream from the sub-scanning distance from the leading edge of the document to the second conveying roller and the first reading means. By calculating the difference from the calculated average value of relative displacements in the sub-scanning direction,
2. The image reading according to claim 1, wherein the rotational driving of the first and second transport rollers is adjusted and controlled so that the document transport speed by the first and second transport rollers is constant. Device adjustment method. In the adjustment method, when the main scanning direction is the X coordinate and the sub scanning direction is the Y coordinate,
The Y coordinate of each linear image extending in the main scanning direction is
The method of adjusting the image reading apparatus according to claim 1, wherein the calculation is performed using a center of gravity method. The image reading apparatus uses the adjustment method according to claim 1. An electrophotographic or inkjet image forming apparatus that forms an image corresponding to an image information signal read by the image reading apparatus,
The image forming apparatus includes the image reading apparatus according to claim 4.

Images