JP2005210493A - Draft reader, draft reading method, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately output a paper size of a draft even if the draft is placed to be inclined to the reference position of the draft, and improve much more operability at a time of draft setting compared with conventional systems. <P>SOLUTION: A draft 20 is arranged by making the image formation face upwards on a platen cover 50 which has a different color from the paper color of the draft 20, and a size larger than the paper size of the draft 20. The apparatus comprises a scanner 11 which scans the platen cover 50 including the image formation face of the draft 20, and obtains an image data Din; a reader and processor 81 which develops the image data Din, and detects the paper image of the draft from the acquired image of the platen cover 50; an inclining corrector 82 which compares the paper image of the draft 20 and a reference position established beforehand, and corrects inclining of the paper image for the reference position; and a size detector 83 which calculates the paper size of the draft 20 after calculation of coordinates of top points of the paper image after correction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a scanner that reads a document of an arbitrary size and outputs document image information and document sheet size information, a digital copying machine that forms an image on a predetermined sheet based on document image information and document sheet size information, The present invention relates to a document reading apparatus, a document reading method, and an image forming apparatus that are suitable for application to a multi-function peripheral.

  In recent years, black and white and color printers and copiers that form images based on arbitrary image information, and multi-function peripherals thereof are often used. For example, a digital copier for black and white includes an image forming unit including an exposure unit, a developing unit, a photosensitive drum, and a fixing device in addition to a scanner function.

  The original is read by a scanner, and the original image is binarized to become image information. The exposure means draws an electrostatic latent image on the photosensitive drum based on the image information after image processing. In the developing device, a black toner agent is attached to the electrostatic latent image drawn on the photosensitive drum and developed. The toner image is transferred from the photosensitive drum to a sheet and then fixed by a fixing device. As a result, an image can be formed on the paper fed from the paper feed tray.

  By the way, this type of digital copying machine includes an apparatus having a function of reading the inclination of an original placed on the platen glass and correcting the inclination, and an original twice to detect the paper size of the original. An apparatus for reading is devised.

  In relation to a copying machine having such a document inclination correction function, Patent Document 1 discloses an image inclination correction apparatus, an original reading apparatus, and an image forming apparatus. According to this document reading device, a calculation means for calculating the maximum correction angle from the memory capacity for inclination correction, the magnification and the document size is provided, and a warning is displayed when the document is set to be tilted beyond the maximum correction angle. In addition, correction correction and the like are performed. With such a configuration, it is possible to provide a copying machine or the like that operates properly, does not malfunction, and is highly reliable and easy to use with respect to a document set with a large inclination exceeding the maximum correction angle. That's it.

  Patent document 2 discloses an image reading method. According to this image reading method, when reading an image from a manuscript, a screen capable of changing white and black is prepared, the manuscript image is read using two screens of white and black, and the two images obtained here are read. The document image data is compared, the size of the document image is detected, and the skew of the document is corrected. With this configuration, an accurate document size can be acquired even when the document is set at an angle.

JP 2000-244728 A (page 3, FIG. 1) JP 2002-271585 A (2nd page, FIG. 1)

  By the way, according to a conventional copying machine equipped with a document inclination correction function and its paper size detection function, there are the following problems.

  i. The document reading device disclosed in Patent Document 1 performs warning display, correction correction, and the like when a document is set with an inclination exceeding the maximum correction angle. Therefore, it is necessary to determine whether or not the original has been set beyond the maximum correction angle each time the original is read. Hinder improvement.

  ii. In the image reading method disclosed in Patent Document 2, when detecting the paper size of an original, the original image must be read using two screens of white and black. Therefore, since the detection time of the paper size of the document becomes long, there is a possibility that the time from when the document is set to when the document is imaged and output becomes long.

  Therefore, the present invention solves such a problem related to the conventional example, and can accurately output the paper size of the original even when the original is inclined with respect to the reference position. It is another object of the present invention to provide a document reading apparatus, a document reading method, and an image forming apparatus that can further improve the operability when setting a document compared to the conventional method.

  In order to solve the above-described problems, an original reading apparatus according to the present invention is an apparatus that reads an original of an arbitrary size and outputs original image information and original paper size information, and has a color different from the original paper color. And a background medium having a size larger than the paper size of the original, and a background medium including the image forming surface of the original, the original having an image forming surface facing the background medium An image reading means for acquiring document image information by scanning the image, an image detection means for detecting a paper image of a document that expands the document image information acquired by the image reading means and partitions the acquired image of the background medium, and A correction means for comparing the paper image of the document output from the image detection means with a preset reference position and correcting the inclination of the paper image with respect to the reference position, and the correction means Calculated vertex coordinate values of the paper image after and is characterized by comprising calculating means for calculating the paper size of the document based on the vertex coordinate values.

  According to the document reading device of the present invention, when a document of an arbitrary size is read and document image information and document paper size information are output, the document has a color different from the document paper color, and the document When a document with the image forming surface on the background medium having a size larger than the paper size is arranged, the image reading unit scans the background medium including the image forming surface of the document to scan the document image. Get information. The image detecting means detects the paper image of the original that develops the original image information acquired by the image reading means and partitions the acquired image of the background medium. Based on this assumption, the correction means compares the paper image of the document output from the image detection means with a preset reference position to correct the inclination of the paper image with respect to the reference position. The vertex coordinate value of the subsequent paper image is obtained, and the paper size of the document is calculated based on the vertex coordinate value. For example, the calculation means obtains the width and length of the original sheet from the four vertex coordinate values of the corrected sheet image (size detection calculation process).

  Therefore, even when the document is placed at an inclination with respect to the reference position, the paper size of the document can be output accurately. In addition, since the operation of aligning the document with the reference position as in the conventional method is not required, it is possible to save twice the trouble of resetting the document one by one when the document slightly deviates from the reference position. . Compared with the conventional method, the operability at the time of document setting is further improved.

  A document reading method according to the present invention is a method of reading document image information from a document of an arbitrary size, and has a color different from the paper color of the document and has a size larger than the paper size of the document. A document with an image forming surface facing the background medium is placed, the background medium including the image forming surface of the document placed on the background medium is scanned to obtain document image information, and the document obtained here Detect the paper image of the document that expands the image information and partitions the acquired image on the background medium, compares the detected paper image of the document with the preset reference position, and tilts the paper image with respect to the reference position Is corrected, the vertex coordinates of the corrected paper image are obtained, and the paper size of the document is calculated based on the vertex coordinates.

  According to the document reading method of the present invention, when document image information is read from a document of an arbitrary size, the document image information and the paper size of the document can be acquired simultaneously by one scan. In addition, the paper size of the document can be acquired with high accuracy.

  An image forming apparatus according to the present invention is an apparatus that reads a document of an arbitrary size and forms a document image on a sheet of a predetermined size, a document reading device that reads the document and outputs document image information, and the document Image forming means for forming a document image on a paper of a predetermined size based on document image information and document paper size information output from the reading device, the document reading device has a color different from the paper color of the document, In addition, a background medium having a size larger than the paper size of the document and a document with an image forming surface facing the background medium are arranged, and the background medium including the image forming surface of the document is scanned. Image reading means for acquiring document image information, and image detection means for detecting a paper image of a document that expands the document image information acquired by the image reading means and partitions the acquired image of the background medium, The paper image of the document output from the image detecting means is compared with a preset reference position to correct the inclination of the paper image with respect to the reference position, and the paper image corrected by the correction means And calculating means for calculating the paper size of the document based on the vertex coordinate values.

  According to the image forming apparatus of the present invention, the original reading apparatus according to the present invention is applied. Therefore, when an original of an arbitrary size is read to form an original image on a predetermined size of paper, the original is positioned at the reference position. Even when the image is placed at an angle to the image, an image is formed on a sheet having a size that matches the sheet size of the document.

  Accordingly, it is possible to prevent the document image from being formed and output on a sheet having a different size, or from being formed and output in a bent state. In addition, since the operation of aligning the document with the reference position as in the conventional method is not required, it is possible to save twice the trouble of resetting the document one by one when the document slightly deviates from the reference position. .

  According to the document reading apparatus of the present invention, when a document of an arbitrary size is read and document image information and document sheet size information are output, the document image of the document is compared with a preset reference position. The inclination of the paper image with respect to the reference position is corrected, a vertex coordinate value of the paper image after the correction is obtained, and calculation means for calculating the paper size of the document based on the vertex coordinate value is provided.

  With this configuration, even when the document is placed at an inclination with respect to the reference position, the paper size of the document can be accurately output. In addition, since the operation of aligning the document with the reference position as in the conventional method is not required, it is possible to save twice the trouble of resetting the document one by one when the document slightly deviates from the reference position. . Compared with the conventional method, the operability during document setting is further improved.

  According to the document reading method of the present invention, a document having an image forming surface as a front is arranged on a background medium having a predetermined color and size, and then the background medium including the image forming surface of the document is scanned. The original image information is acquired, the original image information is expanded to detect the original paper image that partitions the acquired image on the background medium, and the detected original paper image is compared with a preset reference position. Then, the inclination of the paper image with respect to the reference position is corrected, the vertex coordinates of the corrected paper image are obtained, and the paper size of the document is calculated based on the vertex coordinates.

  With this configuration, the original image information and the paper size of the original can be acquired simultaneously by one scan. In addition, the paper size of the document can be acquired with high accuracy.

  According to the image forming apparatus of the present invention, the original reading apparatus according to the present invention is applied. Therefore, when an original of an arbitrary size is read to form an original image on a predetermined size of paper, the original is positioned at the reference position. Even when the image is placed at an angle to the image, an image is formed on a sheet having a size that matches the sheet size of the document.

  With this configuration, it is possible to prevent the document image from being formed and output on paper of different sizes, or the document image being formed and output in a bent state. In addition, since the operation of aligning the document with the reference position as in the conventional method is not required, it is possible to save twice the trouble of resetting the document one by one when the document slightly deviates from the reference position. . Accordingly, it is possible to provide a copying machine and the like that can easily perform manuscript setting operations.

  Next, an embodiment of a document reading apparatus, a document reading method, and an image forming apparatus according to the present invention will be described with reference to the drawings.

(1) Document Reading Device FIG. 1 is a conceptual diagram showing a configuration example of a scanner 100 as a first embodiment according to the present invention.
In this embodiment, when a document of an arbitrary size is read and document image information is output, the sheet image of the document is compared with a preset reference position to correct the inclination of the sheet image with respect to the reference position. The control means for calculating the vertex coordinate value of the corrected paper image and calculating the paper size of the document based on the vertex coordinate value, even when the document is placed at an inclination with respect to the reference position, In addition to being able to output the paper size of the original document accurately, the operability at the time of document setting can be further improved as compared with the conventional system.

  A scanner 100 shown in FIG. 1 is an example of a document reading device, and is a device that reads a document of an arbitrary size and outputs document image information and document sheet size information. The scanner 100 has a scanner main body 11a, and is suitable for application to black and white and color digital copiers and multifunction machines that form images on predetermined paper based on original image information and original paper size information. is there.

  For example, an automatic document feeder (ADF) 40 is attached to the scanner body 11a and operates to automatically feed an arbitrary document 20. The ADF 40 includes a document placing portion 41, a roller 42 a, a roller 42 b, a roller 43, a transport roller 44, and a paper discharge tray 46. One or a plurality of documents 20 are placed on the document placing portion 41.

  A roller 42 a and a roller 42 b are provided on the downstream side of the document placing portion 41. When the automatic paper feeding mode is selected, the document 20 fed out from the document placing portion 41 is U-shaped by the downstream roller 43. It is conveyed so as to rotate. In the automatic paper feeding mode, the recording surface of the document 20 is placed upward on the document placement unit 41. Below the ADF 40, a scanner unit 11 as an example of an image reading unit is provided to read a document image based on an automatic paper feed mode or a platen mode.

  Here, the automatic paper feeding mode refers to an operation of automatically feeding a document 20 placed on the ADF 40 and automatically reading a document image. The platen mode refers to an operation of scanning a document 20 placed on a platen glass and automatically reading a document image. For example, in the automatic paper feeding mode, the scanner unit 11 reads the surface of the document 20 and outputs the image data Din when the document 20 is reversed in a U shape by the roller 43. It is made like. The document 20 read by the scanner unit 11 is transported by the transport roller 44 and discharged to the discharge tray 46.

  On the other hand, a platen cover (reading cover) 50 as an example of a background medium is provided below the ADF 40. The platen cover 50 has a color (reflection color) different from the paper color of the document 20 and a size larger than the paper size of the document 20. In the scanner unit 11 provided below the ADF 40, the platen cover including the image forming surface of the document 20 is disposed in the platen mode in which the document 20 with the image forming surface facing the platen cover 50 is disposed. 50 is scanned to obtain document image information.

  The scanner unit 11 includes, for example, a first platen glass 51, a second platen glass 52, a light source 53, mirrors 54, 55, and 56, an imaging optical unit 57, a CCD imaging device 58, and an optical system drive unit (not shown). doing. The document 20 is set on the platen glass 51 with the document recording surface facing downward, and is pressed by the platen cover 50 described above. In this state, the scanner unit 11 operates the optical system driving unit to scan the light source 53 and the mirrors 54, 55, and 56 with respect to the platen cover 50 including the image forming surface of the document 20. The scanner unit 11 is provided with a CCD imaging device 58 that constitutes a reduction type image sensor, and outputs a document reading signal Sin obtained by reading the document 20.

  A control unit 15 and an image processing unit 80 are provided inside the scanner body 11a. The image processing unit 80 includes, for example, a reading processing unit 81, an inclination correction unit 82, and a size detection unit 83. The read processing unit 81 is an example of an image detection unit, and is connected to the CCD imaging device 58 of the scanner unit 11. The reading processing unit 81 is provided with an analog / digital converter (hereinafter referred to as A / D converter) (not shown). The document reading signal Sin input from the CCD image pickup device 58 is A / D converted to obtain binary document image information ( Hereinafter, the image data Din) is output.

  The reading processing unit 81 has a memory (not shown), and operates to detect the paper image of the document 20 that develops the image data Din in the memory and partitions the acquired image of the platen cover 50. For example, the reading processing unit 81 obtains four vertex coordinate values of the paper image from the binary matrix. Of course, the reading processing unit 81 executes γ correction processing, shading correction, timing control, interline correction processing, and the like on the image data Din in the same manner as in the conventional example, and the image data Dout after image processing is transferred to a printer or the like. It is made to output.

  An inclination correction unit 82 is connected to the reading processing unit 81, and the sheet image of the document 20 based on the image data Din output from the reading processing unit 81 is compared with information related to a preset reference position, with respect to the reference position. It operates to correct the inclination of the paper image. For example, the inclination correction unit 82 performs correction so as to eliminate the inclination angle θ of the paper image based on the four vertex coordinate values of the paper image obtained by the reading processing unit 81. At this time, the inclination correction unit 82 executes graphic rotation processing or the like so that one side of the paper image is parallel to the reference line that defines the reference position. Thereby, the inclination of the original paper 20 'can be corrected so as to eliminate the difference in the paper image with respect to the reference position.

  The reading processing unit 81 is connected to a size detection unit 83 which is an example of a calculation unit, obtains the vertex coordinate value of the corrected paper image, and calculates the paper size of the document 20 based on the vertex coordinate value. For example, the size detection unit 83 is formed of a microprocessor or the like, and executes size detection calculation processing for obtaining the width and length of the original paper 20 ′ from the four vertex coordinate values of the corrected paper image to obtain original paper size information ( Dsz (hereinafter simply referred to as size data) is output. Accordingly, the size data Dsz can be detected from the reading processing unit 81 to the printer or the like in addition to the image data Dout.

  Control means 15 is connected to the reading processing unit 81. A CPU or the like is used for the control means 15, and an operation means 14 provided in the scanner body 11a is connected. The operation means 14 is operated to output image data Dout and size data Dsz obtained by reading an arbitrary document 20 to a printer or the like. The operation means 14 is provided with a start key (not shown), and the document 20 is placed on the ADF 40. When the start key is pressed, the automatic feeding mode is set, and the document 20 placed on the ADF 40 is automatically fed. The document image is automatically read. When the start key is pressed while the document 20 is placed on the platen glass, the platen mode is set, and the document 20 placed on the platen glass is scanned to automatically read the document image. Made.

  2A to 2C are diagrams illustrating examples of image processing in the platen mode. FIG. 2A is a diagram illustrating an example of the relationship between the document 20 and the platen cover 50 in the platen mode. The platen cover 50 shown in FIG. 2A has a color (reflective color) different from the paper color of the original 20 and has a size larger than the paper size of the original 20. In this example, a state in which the document 20 is set obliquely with respect to the platen cover 50 is shown. For example, it is a case where the angle θ is set with respect to the reference position (reference line). In such a state, the scanner unit 11 provided below the ADF 40 shown in FIG. 1 has the document 20 with the image forming surface facing the platen cover 50 in the platen mode. The platen cover 50 including the image forming surface is scanned to acquire image data Din.

  FIG. 2B is a diagram illustrating a relationship example between the document sheet image 20 ′ and the platen cover image 50 ′ in the platen mode. In FIG. 2B, the horizontal axis is the horizontal direction (H direction), and the vertical axis is the vertical direction (V direction). In FIG. 2B, a black portion is a document sheet image 20 'including a document image developed in a memory or the like by the reading processing unit 81 shown in FIG. 1, and a white portion around it is a platen cover image 50'. In this way, in order to clearly separate the original paper image 20 ′ and the platen cover image 50 ′, the platen cover 50 having a color (reflection color) different from the paper color of the original 20 may be prepared.

  FIG. 2C is a binary matrix diagram showing an example of the relationship between the image near the vertex of the original paper 20 'and the platen cover image 50' in the platen mode. In FIG. 2C, an HV image processing system is defined to specify the position of the vertex pixel. In this HV image processing system, the pixel position of a certain vertex pixel Dij is expressed by (hi, vj).

  In the binary matrix diagram shown in FIG. 2C, the image near the apex of the original paper 20 'is obtained by extracting and enlarging an image near the apex from the black original paper image 20' shown in FIG. 2B. In this example, when a total of 10 × 15 pixels of 10 pixels in the main scanning direction and 15 pixels in the sub-scanning direction are extracted in a matrix, each of the lattices forms a pixel Gij.

  In FIG. 2C, the portion of logical value “0” is the platen cover image 50 ′. The portion of logical value “1” is the original paper image 20 ′. In this example, the pixel at the vertex is G38, the vertex pixel G38 has a logical value “1”, and the surrounding area has a logical value “0”. When the position is expressed by the HV image processing system, (h8, v3) is obtained. On the left side of the vertex pixel G38, the pixels G47, G56, G65, G74, G83, G92, and G101 form an edge image of the original paper image 20 '. Further, pixels G49, G510, G611, G712, G813, G914, and G1015 form another edge image of the original paper on the right side of the vertex pixel G38.

  3A, 3B, 4A, and 4B are diagrams showing examples of extracting the first to fourth vertices # 1 to # 4 of the document sheet image 20 'in the platen mode. In this example, on the assumption that the original paper image 20 ′ has a rectangular shape, the reading processing unit 81 starts from the upper left of the binary matrix, for example, in the horizontal direction (H direction) and the vertical direction (V direction). ) To find four vertices. The fourth vertex (the last vertex) may be calculated without being extracted.

  In FIG. 3A, first, the pixel position of the first vertex # 1 is searched. For example, a pixel G1 that is predicted to be a certain vertex pixel is searched, and when the logical value of the pixel G1 is “1” and its surroundings have a logical value “0”, the first vertex coordinate is determined. The In the example shown in FIG. 3A, when the vertex # 1 is expressed by the HV image processing system including the reference line in the platen cover 50, the pixel position coordinates of the vertex pixel G1 when the origin (0, 0) is used as a reference. Is represented by G1 (h1, v1).

  Next, the pixel position of the second vertex # 2 is searched. In the example shown in FIG. 3A, an edge image of the original paper image 20 'is formed on the left side of the vertex pixel G1. Along with this, if the scanning is continued in the horizontal and vertical directions, the second vertex pixel is found. Then, the pixel position coordinate of the second vertex # 2 at which the logical value of the vertex pixel G2 is “1” and the surrounding logical value is “0” is determined. In this example, as shown in FIG. 3B, the pixel position coordinate of the second vertex pixel G2 is indicated by G2 (h2, v2).

  In FIG. 4A, the pixel position of the third vertex # 3 is searched. An edge image of the original paper image 20 'is formed on the right side of the vertex pixel G1 shown in FIG. 4A. Along with this, if the scanning is continued in the horizontal and vertical directions, the third vertex pixel is found. Then, the pixel position coordinate of the third vertex # 3 in which the logical value of the vertex pixel G3 is “1” and the surrounding logical value is “0” is determined. In this example, as shown in FIG. 4A, the pixel position coordinate of the third vertex pixel G3 is indicated by G3 (h3, v3).

  Similarly, in FIG. 4B, the pixel position of the fourth vertex # 4 is searched. An edge image of the original paper image 20 'is formed on the left side of the vertex pixel G3 shown in FIG. Along with this, if the scanning is continued in the horizontal and vertical directions, the fourth vertex pixel is found. Then, the pixel position coordinates of the fourth vertex # 4 at which the logical value of the vertex pixel G4 is “1” and the surrounding logical value is “0” are determined. In this example, as shown in FIG. 4B, the pixel position coordinate of the fourth vertex pixel G4 is indicated by G4 (h4, v4).

  FIGS. 5A and 5B are diagrams showing an example of inclination correction (part 1) of the original paper image 20 ′ in the platen mode. FIG. 5A shows the original paper image 20 ′ and the platen cover image 50 ′ after the system conversion. It is a figure which shows the example of a relationship.

  In this example, the inclination correction unit 82 compares the document sheet image 20 ′ of the document 20 based on the image data Din output from the reading processing unit 81 with information related to a preset reference position, and the document corresponding to the reference position. It operates to correct the inclination of the paper image 20 ′. For example, the inclination correction unit 82 has pixel coordinates G1 (h1, v1), G2 (h2, v2), G3 (h3, v3), and G4 of the four vertices of the original paper image 20 ′ obtained by the reading processing unit 81. The inclination angle θ of the original paper image 20 ′ is corrected based on (h4, v4). At this time, the inclination correction unit 82 performs graphic rotation processing or the like so that one side of the original paper image 20 ′ is parallel to a reference line that defines a reference position. Thereby, the inclination of the original paper image 20 ′ can be corrected so as to eliminate the inclination angle θ of the original paper image 20 ′ with respect to the reference position.

In FIG. 5A, the horizontal axis represents the sub-scanning direction (X direction) in the XY scanning system, and the vertical axis represents the main scanning direction (Y direction).
In this example, the pixel coordinates G1 (h1, v1), G2 (h2, v2), G3 of the first to fourth vertices when the original paper image 20 ′ described in FIGS. 3A, 3B, 4A and 4B is tilted. (H3, v3) and G4 (h4, v4) are converted into the position coordinates of the vertices A to D in the XY scanning system. For example, the pixel position coordinates G1 (h1, v1) of the first vertex pixel G1 shown in FIG. 3A are converted into position coordinates B (x2, y2) showing the vertex B as shown in FIG. 5A. Note that x2 and y2 are x2 = α1 · h1 and y2 = β1 · v1, where α1 and β1 are conversion constants.

  Similarly, the pixel position coordinate G2 (h2, v2) of the second vertex pixel G2 is converted into a position coordinate A (x1, y1) indicating the vertex A. Note that x1 and y1 are x1 = α2 · h2 and y2 = β2 · v2, where α2 and β2 are conversion constants. The pixel position coordinate G3 (h3, v3) of the third vertex pixel G3 is converted into a vertex position coordinate D (x4, y4) indicating the vertex D. Note that x4 and y4 are x4 = α3 · h3 and y4 = β3 · v3, where α3 and β3 are conversion constants. The pixel position coordinates G4 (h4, v4) of the fourth vertex pixel G4 are converted into vertex position coordinates C (x3, y3) indicating the vertex C, respectively. Note that x3 and y3 are x3 = α4 · h4 and y3 = β4 · v4 when the conversion constants are α4 and β4.

  FIG. 5B is a diagram illustrating an example of inclination correction of the original paper image 20 ′ after coordinate conversion. In this example, the four vertex position coordinates obtained in FIG. 5A = A (x1, y1), B (x2, y2), C (x3, y3), D (x4, y4) are obtained, and to correct. Here, correction is performed using a straight line of the line segment AC. For example, a matrix in the case of “no original paper tilt” is developed in the memory, and pixel values constituting the original paper image 20 ′ are described in each lattice point. In this example, the pixel value of the vertex A is described in the lattice point a, and the pixel value of the position advanced by one pixel from the coordinate A in the inclination direction of the line segment AB is described in the lattice point b.

  If the description process of such pixel values is continued, the result is equivalent to excluding the inclination angle θ, and each vertex of the matrix has four vertex position coordinates = A (x1, y1), B (x2, y2), Pixel values G1, G2, G3, and G4 relating to C (x3, y3) and D (x4, y4) are respectively described (graphic rotation processing).

  FIG. 6 is a diagram showing an example of the inclination correction (part 2) of the original paper image 20 ′ in the platen mode, and is a diagram showing an example of the relationship between the corrected original paper image 20 ′ and the platen cover image 50 ′. . In FIG. 6, the horizontal axis is the sub-scanning direction (X direction) in the XY scanning system, and the vertical axis is the main scanning direction (Y direction). The vertices A 'to D' of the corrected original paper image 20 'are equivalent to the case where the inclination angle θ in the figure is set to 0 °, that is, no inclination.

  In this example, the position coordinates of the vertex A ′ are (X1, Y1), the position coordinates of the vertex B ′ are (X2, Y2), the position coordinates of the vertex C ′ are (X3, Y3), and the vertex The position coordinates of D ′ are (X4, Y4).

From this coordinate acquisition result, the distance between the vertices A'-B 'is (X2-X1), and the distance between the vertices C'-D' is (X4-X3). Similarly, the distance between the vertices A′-C ′ is (Y3-Y1), and the distance between the vertices B′-D ′ is (Y4-Y2). Size data (original paper size information) Dsz is determined from these pieces of information. In this example, if the length of the document 20 is L, the length L is the expression (1), that is,
L = X2-X1 (1)
Given in. The length L may be a distance between C ′ and D ′, that is, L = X4−X3.

Further, if the width of the document 20 is W, the width W is expressed by equation (2), that is,
W = Y3-Y1 (2)
Given in. The width W may be a distance between D ′ and D ′, that is, W = Y4−Y2. When the scanner 100 is configured in this manner, the size data Dsz can be output to a printer or the like in addition to the image data Dout equivalent to the case where the document 20 is not tilted. Therefore, the document 20 is placed on the platen glass. Even when the original 20 is displaced after the ADF 40 is closed, there is no need to reset the original 20 again. It is possible to save the user from the trouble of resetting.

Next, the document reading method according to the present invention will be described. FIG. 7 is a flowchart illustrating an example of document reading by the scanner 100.
In this embodiment, a platen cover 50 having a color different from the paper color of the original 20 and having a size larger than the paper size of the original 20 is provided in advance on the back surface of the ADF 40, etc. 20 is read, and image data Din and size data Dsz of the document 20 are output to a printer or the like. In this example, it is assumed that the control is branched based on the platen mode or the automatic paper feed mode. The automatic paper feed mode is automatically set by placing the document 20 on the ADF 40, and the platen mode is automatically set by placing the document 20 on the platen glass.

  Under these document reading conditions, the control unit 15 waits for a document set in step P1 of the flowchart shown in FIG. At this time, the user opens the ADF 40 on the platen glass upward, places the document 20 with the image forming surface turned down on the platen glass, and then operates the ADF 40 downward to cover the platen cover 50. As a result, the document 20 placed on the platen glass is covered with the platen cover 50 with the image forming surface facing downward (see FIG. 2A). The document 20 on the platen glass is recognized by the control means 15 by a sheet detection signal indicating that “the document has been set on the platen glass” by a known sheet detection technique.

  Thereafter, in step P2, the control means 15 branches control by pressing a start / stop key or the like. If the start key is pressed, the process proceeds to step P3, and the control is further branched based on the platen mode or the automatic paper feed mode. When the platen mode is set, the process proceeds to step P4, and the scanner unit 11 scans the document 20 including the image forming surface and the entire platen cover to read an image. The reading processing unit 81 A / D converts the document reading signal Sin output from the CCD imaging device 58 to obtain binary image data Din (binary matrix) (see FIG. 2C).

  In step P5, the reading processing unit 81 expands the image data Din and detects the document sheet image 20 'of the document 20 that partitions the acquired image of the platen cover 50. In this example, the four vertexes G1 to G4 of the document 20 are obtained from the binary image data Din in the HV image processing system. At this time, the reading processing unit 81 searches for the pixel position of the first vertex # 1 as shown in FIG. 3A. For example, a pixel G1 that is predicted to be a certain vertex pixel is searched, and when the logical value of the pixel G1 is “1” and its surroundings have a logical value “0”, the first vertex coordinate is determined. The In the example shown in FIG. 3A, the pixel position coordinate of the vertex pixel G1 is expressed by G1 (h1, v1) with respect to the vertex # 1.

  Similarly, the reading processing unit 81 searches for the pixel position of the second vertex # 2. In this example, as shown in FIG. 3B, the pixel position coordinate of the vertex pixel G2 is indicated by G2 (h2, v2). Thereafter, the pixel position of the third vertex # 3 is searched. In this example, as shown in FIG. 4A, the pixel position coordinate of the vertex pixel G3 is indicated by G3 (h3, v3). Then, the pixel position of the fourth vertex # 4 is searched. In this example, as shown in FIG. 4B, the pixel position coordinate of the vertex pixel G4 is indicated by G4 (h4, v4).

  Then, the process proceeds to step P6, where the reading processing unit 81 performs pixel coordinates G1 (h1, v1) and G2 (h2, v2) of the first to fourth vertices of the HV image processing system shown in FIG. 5A. , G3 (h3, v3), G4 (h4, v4) are converted into position coordinates of the vertices A to D in the XY scanning system. For example, the pixel position coordinates G1 (h1, v1) of the first vertex pixel G1 shown in FIG. 3A are converted into position coordinates B (x2, y2) showing the vertex B as shown in FIG. 5A. Similarly, the pixel position coordinate G2 (h2, v2) of the second vertex pixel G2 is converted into a position coordinate A (x1, y1) indicating the vertex A. The pixel position coordinate G3 (h3, v3) of the third vertex pixel G3 is converted into a vertex position coordinate D (x4, y4) indicating the vertex D. The pixel position coordinates G4 (h4, v4) of the fourth vertex pixel G4 are converted into vertex position coordinates C (x3, y3) indicating the vertex C, respectively.

  Thereafter, the process proceeds to step P7, where the inclination correction unit 82 compares the original paper image 20 'with a preset reference position, and executes a paper image inclination correction process with respect to the reference position. For example, the inclination correction unit 82 has pixel coordinates A (x1, y1), B (x2, y2), C (x3, y3), D (x4, 4) of the four vertices of the paper image obtained by the reading processing unit 81. Based on y4), correction is performed so that the inclination angle θ of the paper image becomes zero.

  At this time, according to the example shown in FIG. 5B, the four vertex position coordinates of the original paper image 20 ′ after the coordinate conversion = A (x1, y1), B (x2, y2), C (x3, y3), The inclination is obtained from D (x4, y4), and each is corrected. Here, correction is performed using a straight line of the line segment AC. For example, as shown in FIG. 5B, a matrix in the case of “no original paper inclination” is developed, and pixel values constituting the original paper image 20 ′ are described in each lattice point. In this example, the pixel value of the vertex A is described in the lattice point a, and the pixel value of the position advanced by one pixel from the coordinate A in the inclination direction of the line segment AB is described in the lattice point b.

  If the description process of such pixel values is continued, the result is equivalent to excluding the inclination angle θ, and each vertex of the matrix has four vertex position coordinates = A (x1, y1), B (x2, y2), Pixel values G1, G2, G3, and G4 relating to C (x3, y3) and D (x4, y4) are respectively described (graphic rotation processing). By this graphic rotation processing, one side of the paper image becomes parallel to the reference line that defines the reference position, and the inclination angle θ of the paper image with respect to the reference position is eliminated. Here, the vertices A to D of the original paper image 20 'after the inclination correction processing are rewritten as vertices A' to D 'as shown in FIG. In this example, the position coordinate of the vertex A ′ is A ′ (X1, Y1), the position coordinate of the vertex B ′ is B ′ (X2, Y2), and the position coordinate of the vertex C ′ is C ′ (X3, Y3). Y3), and the position coordinates of the vertex D ′ are D ′ (X4, Y4).

  In step P8, the size detection unit 83 calculates the paper size of the document 20 based on the vertex coordinates A ′ to D ′. At this time, the size detection unit 83 calculates the length L = X2−X1 of the document 20 based on the position coordinates (X1, Y1) of the vertex A ′ and the position coordinates (X2, Y2) of the vertex B ′. Further, the width W = Y3-Y1 of the document 20 is calculated based on the position coordinates (X1, Y1) of the vertex A ′ and the position coordinates (X3, Y3) of the vertex C ′ (size detection process). The information regarding the length L = X2-X1 and the width W = Y3-Y1 is the size data Dsz of the document 20.

  In step P9, the image data Din and the size data Dsz are output to a printer or the like. Thereafter, the process proceeds to step P11. If the automatic paper feed mode is set in step P3, the process proceeds to step P10 to execute automatic document feed reading processing. For example, the document 20 fed out from the document placing unit 41 is conveyed by the downstream roller 43 so as to rotate in a U-shape. In the automatic paper feeding mode, the recording surface of the document 20 is placed upward on the document placement unit 41. The scanner unit 11 provided below the ADF 40 reads a document image. Thereafter, the process proceeds to step P11.

  If the stop key is pressed in step P2 described above, the process proceeds to step P11, and the control unit 15 determines whether to end the document reading process. For example, the control unit 15 detects the power-off information and ends the document reading process. If the power-off information is not detected, the process returns to step P1 and the above-described processing is repeated.

  As described above, according to the scanner and the document reading method as the first embodiment according to the present invention, when the document 20 of an arbitrary size is read and the image data Din and the size data Dsz are output, the inclination correction unit 82 compares the original paper image 20 ′ output from the reading processing unit 81 with a preset reference position and corrects the inclination of the paper image with respect to the reference position, and the size detection unit 83 corrects the corrected paper image. , And the paper size of the document 20 is calculated based on the vertex coordinate value. At this time, the size detection unit 83 has four vertex coordinates A ′ (X1, Y1), B ′ (X2, Y2), C ′ (X3, Y3) or D ′ (X4, Y4) of the corrected paper image. The width W and the length L of the sheet of the document 20 are obtained from the above (size detection calculation processing).

  Therefore, even when the document 20 is placed at an inclination with respect to the reference position (reference line), the paper size of the document 20 can be output accurately. In addition, since the operation of aligning the original 20 with the reference position as in the conventional method is not required, it is possible to save the time and trouble of re-setting the original 20 while paying attention to the slight deviation of the original 20 from the reference position. be able to. In addition, it is possible to perform document inclination correction and size detection at the same time by one reading process, and the operability at the time of document setting is further improved as compared with the conventional method.

(2) Image Forming Apparatus FIG. 8 is a conceptual diagram showing a configuration example of a monochrome copying machine 200 as a second embodiment according to the present invention.
In this embodiment, the scanner 100 described above is incorporated in a monochrome copying machine 200, and a sheet of a corresponding size is automatically selected from a plurality of paper feed trays based on the size data Dsz output from the scanner 100. The original image is formed on the paper.

  A copying machine 200 shown in FIG. 8 is an example of an image forming apparatus, and reads a document 20 of an arbitrary size and forms a document image on a sheet 30 of a predetermined size. The copying machine 200 constitutes an image forming apparatus of a direct transfer type that obtains a monochrome image. The apparatus main body 201 includes the scanner 100 described with reference to FIGS. 1 to 7, and the scanner 100 includes a platen cover 50. The platen cover 50 has a color different from the paper color of the document, and has a size larger than the paper size of the document.

  The apparatus main body 201 includes a scanner unit 11, paper feed trays # 1 and # 2, an image writing unit 60, an image forming unit 70, a state management control block 202, and the like. For example, an additional paper feeder 35 is attached. The paper feeding device 35 is provided with a large capacity paper feeding tray.

  An automatic document feeder (ADF) 40 is attached to the upper portion of the scanner unit 11 and operates to automatically feed an arbitrary document 20 as described with reference to FIG. On the other hand, the scanner unit 11 provided in the main body device operates to read an arbitrary document 20. For example, when a document with an image forming surface facing the platen cover 50 is arranged, the scanner unit 11 scans the platen cover 50 including the image forming surface of the document. A control block 202 is connected to the CCD image pickup device 58 provided in the scanner unit 11, and a document reading signal Sin is output to an image processing means 80 (not shown) provided in the control block 202. .

  In the control block 202, the document reading signal Sin undergoes A / D conversion processing, tilt correction processing, size detection processing, and the like. The image data Dout after the image processing is output to the image writing unit 60. The image writing unit 60 generates laser light having a predetermined intensity based on the image data Dout. An image forming unit 70 is provided at a position facing the image writing unit 60, and an image is formed based on the image data Din obtained by the scanner unit 11.

  Below the image forming unit 70, a sheet feeding unit 23 having sheet feeding trays # 1 and # 2 is provided. The paper feeding means 23 includes a paper feeding device 35. For example, the paper feeding device 35 is provided with three paper feeding trays # 3 to # 5, and papers 30 of a predetermined size are stored in these paper feeding trays # 1 to # 5.

  The image forming unit 70 forms an image on the paper 30 fed out from one of the paper feed trays # 1 to # 5. The image forming unit 70 includes an organic photosensitive drum (hereinafter referred to as a photosensitive drum) 71, a charger 72, a developing unit 73, a transfer unit 74, a separator 75, a cleaning unit 76, a transport mechanism 77, and a fixing device 78. .

  A charger 72 is disposed above the photosensitive drum 71, and the photosensitive drum 71 is uniformly charged in advance based on a predetermined charging potential. An image writing unit 60 is provided, for example, on the upper right side of the photosensitive drum 71, and laser light having a predetermined intensity based on the image data Dout after image processing is irradiated to expose the photosensitive drum 71 to the drum. An electrostatic latent image is formed.

  On the right side of the photosensitive drum 71, a developing device 73 containing toner and a carrier (developer) is disposed, and the electrostatic latent image exposed by the image writing unit 60 is developed by the toner agent. Below the developing unit 73, a registration roller 62, paper feed trays # 1 and # 2, and the like are provided.

  A transfer device 74 is disposed below the photosensitive drum 71, and a toner image formed on the photosensitive drum 71 through charging, exposure, and development is transferred to a sheet 30 whose conveyance timing is controlled by a registration roller 62. Is done. A separator 75 is provided adjacent to the transfer device 74, and the paper 30 onto which the toner image has been transferred is separated from the photosensitive drum 71. A transport mechanism 77 is provided on the downstream side of the separator 75, and a fixing device 78 is provided at the end thereof. In the fixing device 78, the toner image transferred to the paper 30 is fixed. A cleaning unit 76 is provided between the transport mechanism unit 77 and the above-described charger 72 so as to face the photoconductive drum 71, and the toner remaining on the photoconductive drum 71 is cleaned.

  When double-sided copying is selected in this example, an image is formed on one side (front side) of the paper 30 and an image is also formed on the back side of the paper 30 discharged from the fixing device 78. The sheet 30 discharged from the fixing device 78 is branched from the sheet discharge path by the branching unit 91, and the front and back are reversed by the lower reversing roller 92 and the reversing unit 93 constituting the sheet feeding unit 2323, respectively. The sheet 30 passes through the reverse conveying path 94 and joins the normal sheet feeding path before the sheet feeding roller 61.

The paper 30 that has been transported in the reverse direction passes through the registration rollers 62 and is transported again to the transfer device 74, and the toner image is transferred onto the other surface (back surface) of the paper 30. The sheet 30 on which the toner image is transferred is fixed by the fixing device 78, is sandwiched between the discharge rollers 95, and is discharged to a discharge tray 96 or the like outside the apparatus. The time of forming these images, 52.3~63.9kg / m ² (1000 sheets) about thin and 64.0~81.4kg / m ² (1000 sheets) of approximately plain paper or a paper 30 83 .0~130.0kg / m ² (1000 sheets) about cardboard and 150.0kg / m ² (1000 sheets) about super thick paper is used. As the image forming conditions, it is preferable that the linear velocity is about 80 to 350 mm / sec, and the environmental conditions are a setting condition of a temperature of about 5 to 35 ° C. and a humidity of about 15 to 85%. The thickness of the paper 30 (paper thickness) is about 0.05 to 0.15 mm.

  FIG. 9 is a block diagram illustrating a configuration example of a control system of the copying machine 200. The copying machine 200 shown in FIG. 9 includes a scanner unit 11, a sheet feeding unit 23, a plurality of sheet feeding trays # 1 to # 5, an ADF 40, an operation panel 48 for setting conditions, an image forming unit 70, and a post-processing device (FNS). 90 and a control block 202 for state management.

  The scanner unit 11 and the ADF 40 constitute a document reading apparatus, and the scanner 100 described with reference to FIGS. In this example, the scanner unit 11 is provided with a scanner control unit 11b in addition to the CCD imaging device 58, and the ADF 40 is provided with an ADF control unit 40a. In the platen mode, under the control of the scanner control unit 11b, the scanner unit 11 reads the document 20 and outputs a document reading signal Sin to the control block 202. In the automatic paper feeding mode, under the control of the ADF control unit 40a, the ADF 40 reads the document 20 and outputs a document reading signal Sin to the control block 202.

  The control block 202 is connected with an operation panel 48 for setting conditions. The operation panel 48 includes an operation & control unit 14 ′ and a display unit (LCD) 18. Of the operation & control unit 14 ′, the operation unit is composed of, for example, a touch panel, and the display unit 18 is composed of a liquid crystal display panel. In this example, a touch panel forming an operation unit is combined with a liquid crystal display panel forming a display unit 18 to configure a GUI (Graphic User Interface) type condition setting unit.

  For example, the operation panel 48 is provided with a start / stop key for executing the automatic paper feed mode or the platen mode. The operation & control unit 14 ′ is operated to output image data Dout and size data Dsz obtained by reading an arbitrary document 20 to the image forming unit 70 and the like. The operation panel 48 is operated so as to select the size of the paper 30 prepared in the paper supply means 23.

  The display unit 18 displays the finished state of the original image on the sheet 30 of the size selected by the operation & control unit 14 '(preview display). In this way, it becomes possible to confirm on the display screen the finished state of the original image on the paper size selected by the user by operating the operation & control unit 14 ′ from among several paper 30 candidates.

  Further, a state management control block 202 is connected to the scanner unit 11 and the ADF 40. The control block 202 includes an image memory 13, a nonvolatile memory 21, a system bus 22, a program memory 24, an image control CPU (Central Processing Unit) 25, a system memory 26, a compression / decompression IC 28, and an I / O. It comprises an interface 29, an image writing unit 60, an image processing means 80, and an IC 85 for DRAM control.

  An image processing means 80 is connected to the above-described scanner unit 11, and an original reading signal Sin is input to perform image processing. The image processing unit 80 includes a reading processing unit 81, an inclination correction unit 82, and a size detection unit 83. The reading processing unit 81 A / D converts the document reading signal Sin input from the scanner unit 11 to obtain image data Din. Further, the image data Din is developed on the memory, and the paper image of the document that partitions the acquired image of the platen cover 50 is detected. In addition, the reading processing unit 81 inputs the image data Din, and executes density conversion processing, spatial filter processing, γ correction processing, shading correction processing, timing control, interline correction processing, and the like.

  The inclination correction unit 82 compares the original paper image output from the reading processing unit 81 with a preset reference position, and corrects the inclination of the paper image with respect to the reference position. The size detection unit 83 uses the vertex coordinates A ′ (X1, Y1), B ′ (X2, Y2), C ′ (X3, Y3), and D ′ (X4) of the paper image corrected by the inclination correction unit 82. Y4) is obtained, and the size data (20) of the document 20 based on the vertex coordinates A ′ (X1, Y1), B ′ (X2, Y2), C ′ (X3, Y3) and / or D ′ (X4, Y4) Calculate Dsz (including width W and length L information).

  The CPU 25 for image control is connected to the image processing means 80, and the size data Dsz of the document 20 calculated by the size detection unit 83 is input. A system bus 22 is connected to the CPU 25. In addition to the CPU 25, a nonvolatile memory 21, a program memory (ROM) 24, a system memory (RAM) 26, and an I / O interface 29 are connected to the system bus 22.

  The nonvolatile memory 21 updates and stores content data communicated between the CPU 25 and the paper feed means 23, for example, data such as the types of paper stored in the paper feed trays # 1 to # 5. . As the nonvolatile memory 21, a hard disk (HDD), an EEPROM, or the like is used. HDDs, EEPROMs, and the like are memories that can rewrite data and are not erased even when the power is turned off.

  The program memory 24 stores system program data for controlling the entire copying machine. The system memory 26 is used as a work memory, and temporarily stores control commands, size data Dsz, and the like, for example. When the power is turned on, the CPU 25 reads the system program data from the program memory 24, starts the system, and controls the entire copying machine based on the operation data D3 from the operation & control unit 14 '.

  The I / O interface 29 is connected to a paper feeding unit 23 and operates to feed a predetermined size of paper 30 to the image forming unit 70. For example, the sheet feeding unit 23 performs sheet feeding control for the five sheet feeding trays # 1 to # 5 based on the sheet feeding control signal Sf from the CPU 25. The paper feed control signal Sf includes document size data Dsz.

  In this example, the paper feed unit 23 has five paper feed trays # 1 to # 5 that store papers 30 of different sizes. The CPU 25 receives the size data Dsz of the document 20 from the size detection unit 83, and controls the paper feeding means 23 so as to select the optimum size paper 30 from the five paper feeding trays based on the size data Dsz. To do.

  Sensors S1 to S5 for detecting paper size are attached to the respective paper feed trays # 1 to # 5. The sensor S1 detects the size of the paper 30 set in the paper feed tray # 1, and outputs a size detection signal SP1 to, for example, the paper feeding unit 23. Similarly, the sensor S2 detects the size of the paper 30 set in the paper feed tray # 2, and outputs a size detection signal SP2 to the paper feed means 23.

  The sensor S3 detects the size of the paper 30 set in the paper feed tray # 3 and outputs a size detection signal SP3 to the paper feed means 23. The sensor S4 detects the size of the paper 30 set in the paper feed tray # 4 and outputs a size detection signal SP4 to the paper feed means 23. The sensor S5 detects the size of the paper 30 set in the paper feed tray # 5 and outputs a size detection signal SP5 to the paper feed means 23. The paper feeding means 23 recognizes what size paper 30 is set in which paper feed trays # 1 to # 5 based on the respective size detection signals SP1 to SP5.

  In this example, the paper feeding unit 23 compares the size of the paper 30 prepared in each of the paper feeding trays # 1 to # 5 with the paper size of the document 20 received from the CPU 25, and the result of the comparison is stored in the paper feeding tray. When there is a paper 30 of the corresponding size, the operation is performed to select a paper feed tray that stores the paper 30 of the size. If there is no paper 30 of the corresponding size in the paper feed tray as a result of the comparison, an operation is performed to select a paper feed tray containing the paper 30 of the closest size.

  In addition to the CPU 25, the above-described image processing means 80 is connected to an IC 85 for DRAM control. The IC 85 is further connected to the image memory 13, the compression / decompression IC 28 and the image writing unit 60. The image data Dout output from the reading processing unit 81 is output to the compression / decompression IC 28 under the DRAM control of the IC 85 during document reading. In the IC 28, the image data Dout is compressed. The compressed image data Dout is transferred to the image memory 13 under the DRAM control of the IC 85. A compression memory 27 is constructed in the image memory 13, and the compressed image data Din is temporarily stored.

  The compressed image data Din stored in the image memory 13 is read from the compression memory 27 at the time of image formation. The image data Dout read from the compression memory 27 is output to the compression / decompression IC 28 under the DRAM control of the IC 85. In the IC 28, the image data Dout is expanded. The decompressed image data Dout is transferred to the image writing unit 60 under the DRAM control of the IC 85.

  In the image writing unit 60, the laser drive signal Sd is PWM-modulated based on the image data Dout. An image forming unit 70 is connected to the image writing unit 60 and operates to form an original image on a sheet 30 of a predetermined size based on the image data Din and size data Dsz output from the scanner 100. The image forming unit 70 includes a printer control unit 70b in addition to the laser diode (LD) 70a.

  For example, the modulated laser drive signal Sd is output to the laser diode 70a. The laser diode 70a emits a laser beam having a predetermined intensity based on the laser drive signal Sd. The laser beam emitted from the laser diode 70a is scanned on the photosensitive drum 71 shown in FIG. Thereby, an electrostatic latent image based on the image data Dout is formed (written) on the photosensitive drum 71.

  The electrostatic latent image formed on the photosensitive drum 71 is developed by the toner member under the control of the printer control unit 70b. The developed toner image is transferred to a sheet 30 whose sheet feeding is controlled by the sheet feeding unit 23. The toner image transferred to the paper 30 is fixed and discharged as a copy 30 '. Alternatively, a copy 30 ′ after image formation is post-processed under the control of the FNS controller 90 a by a post-processing device (FNS) 90.

  10A to 10F are conceptual diagrams illustrating examples of selection of the paper size in the paper feeding unit 23. FIG.

  In this example, the size of the original paper as shown in FIG. 10A handled by the paper supply unit 23 is the size of the original 20 read by the scanner unit 11, the length is Lx, and the width is Wx. It is. The length Lx and the width Wx of the document 20 are recognized by the size data Dsz.

  Also, the paper size as shown in FIG. 10B is the paper 30 stored in the paper feed tray # 1, the length is L1, and the width is W1. The length L1 and the width W1 of the paper 30 are recognized by the size detection signal SP1. The paper size shown in FIG. 10C is the paper 30 stored in the paper feed tray # 2, the length is L2, and the width is W2. The length L2 and the width W2 of the paper 30 are recognized by the size detection signal SP2.

  Furthermore, the paper size shown in FIG. 10D is the paper 30 stored in the paper feed tray # 3, the length is L3, and the width is W3. The length L3 and the width W3 of the paper 30 are recognized by the size detection signal SP3. The paper size shown in FIG. 10E is the paper 30 stored in the paper feed tray # 4, the length is L4, and the width is W4. The length L4 and the width W4 of the paper 30 are recognized by the size detection signal SP4.

  The paper size shown in FIG. 10F is the paper 30 stored in the paper feed tray # 5, the length is L5, and the width is W5. The length L5 and the width W5 of the paper 30 are recognized by the size detection signal SP5. The paper feed means 23 recognizes what size paper 30 is set in which paper feed trays # 1 to # 5 based on the respective size detection signals SP1 to SP5.

  In this example, the paper feed unit 23 compares the size of the paper 30 prepared in each of the paper feed trays # 1 to # 5 with the paper size of the document 20 received from the CPU 25. For example, the length Lx of the document 20 and the lengths L1 to L5 of the sheets 30 prepared in the respective sheet feeding trays # 1 to # 5 are sequentially compared. Thereafter, the width Wx of the document 20 and the widths W1 to W5 of the paper 30 prepared in the respective paper feed trays # 1 to # 5 are sequentially compared.

At this time, in the paper feeding means 23, the length of the document 20 is Lx, the width is Wx, the length of the paper 30 registered in advance is L1, L2, L3, L4, or L5, and the width is W1. , W2, W3, W4 or W5, the judgment formula J shown in the formula (2), that is,
J = [Wx− (W1, W2, W3, W4 or W5)] ²
+ [Lx− (L1, L2, L3, L4 or L5)] ² ... (3)
The paper size that minimizes is selected.

  If there is a paper 30 of the corresponding size in any of the five paper feeding trays # 1 to # 5 as a result of this comparison, the paper feeding tray storing the paper 30 of that size is selected. The paper feed unit 23 controls the paper feed trays # 1 to # 5. If there is no paper 30 of the corresponding size in any of the five paper feed trays # 1 to # 5 in the comparison result, the paper feed tray containing the paper 30 of the closest size is selected. The paper feed unit 23 controls the paper feed trays # 1 to # 5.

FIG. 11 is a conceptual diagram showing a display example of the paper size selection screen PR1 on the operation panel 48. As shown in FIG.
In addition to the start key K6 and the stop key K7, the operation panel 48 shown in FIG. The display unit 18 displays a paper size selection screen PR1 when setting image forming conditions. On the paper size selection screen PR1, icon keys K1 to K5 of “size 1” to “size 5” are displayed. The display unit 18 displays a paper size selection screen PR1 based on the display data D2. Five icon keys K1 to K5 are selected in order from the paper size that minimizes the determination formula J based on the formula (3) described with reference to FIG. 10, and are displayed based on the display data D2.

  A preview display area PR2 is provided on the left side of the display area of these icon keys K1 to K5, and an output image on which a document image is formed is displayed on the paper 30 having the size selected on the paper size selection screen PR1. Made. The user can confirm the output image after the image formation in advance without actually forming the image on the paper size selection screen PR1. In this example, “size 2” is selected, and the icon key K2 of “size 2” is highlighted.

  Further, the output image after image formation displayed in the preview display area PR2 is displayed based on the display data D2. The display data D2 relating to the output image after the image formation is created by the CPU 25. For example, the CPU 25 creates display data D2 after the image data Dout of the document 20 is pasted (synthesized) on the paper 30 having the size selected on the paper size selection screen PR1. The display unit 18 displays a preview of the output image after image formation based on the display data D2.

  Next, an example of image formation including document reading in the copying machine 200 will be described. 12 and 13 are flowcharts showing image formation examples (Nos. 1 and 2) in the copying machine 200. FIG.

  In this embodiment, in the copying machine 200 having the function of the scanner 100, even when the document 20 can be detected and the document 20 is set to be tilted without adjusting the document 20 to the reference position, the tilt is automatically corrected. Thus, the trouble of resetting the original 20 can be omitted, and the paper 30 of the corresponding size is selected from the five paper feed trays # 1 to # 5 based on the size data Dsz output from the image processing means 80. Is automatically selected, and a correct original image can be formed on the paper 30.

  Also in this example, it is assumed that control is branched based on the platen mode or the automatic paper feed mode. The automatic paper feed mode is automatically set by placing the document 20 on the ADF 40, and the platen mode is automatically set by placing the document 20 on the platen glass.

  Using these as image forming conditions, the scanner controller 11b waits for a document set in step Q1 of the flowchart shown in FIG. At this time, the user opens the ADF 40 on the platen glass upward, places the document 20 with the image forming surface turned down on the platen glass, and then operates the ADF 40 downward to cover the platen cover 50. As a result, the document 20 placed on the platen glass is covered with the platen cover 50 with the image forming surface facing downward (see FIG. 2A). The document 20 on the platen glass is recognized by the scanner control unit 11b by a known sheet detection technique by a sheet detection signal indicating that “the document has been set on the platen glass”.

  Thereafter, in step Q2, the CPU 25 inputs image forming conditions. At this time, the user operates the operation & control unit 14 'to input image forming conditions. For example, the number of copies and the image density are set. In the automatic paper feed mode, an operation is performed to select a paper feed tray. In the platen mode, the paper feed tray selection operation may or may not be performed.

  In step Q3, the CPU 25 branches the control by pressing the start key K6 or the stop key K7. When the start key K6 is pressed, the process proceeds to step Q4, and the control is further branched based on the platen mode or the automatic paper feed mode. When the platen mode is set, the process proceeds to step Q5, and the scanner control unit 11b controls the optical drive system and the like so as to scan the document 20 including the image forming surface and the entire platen cover and read the image. .

  At this time, the reading processing unit 81 A / D converts the document reading signal Sin output from the CCD image pickup device 58 to obtain binary image data Din (binary matrix) (see FIG. 2C). The reading processing unit 81 also receives the image data Din and executes density conversion processing, spatial filter processing, γ correction processing, shading correction processing, timing control, interline correction processing, and the like.

  In step Q6, the reading processing unit 81 detects the original paper image 20 'that develops the image data Din on the memory and partitions the acquired image on the platen cover 50. In this example, the four vertexes G1 to G4 of the document 20 are obtained from the binary image data Din in the HV image processing system. At this time, the reading processing unit 81 searches for the pixel position of the first vertex # 1 as shown in FIG. 3A. For example, a pixel G1 that is predicted to be a certain vertex pixel is searched, and when the logical value of the pixel G1 is “1” and its surroundings have a logical value “0”, the first vertex coordinate is determined. The In the example shown in FIG. 3A, the pixel position coordinate of the vertex pixel G1 is expressed by G1 (h1, v1) with respect to the vertex # 1.

  Similarly, the reading processing unit 81 searches for the pixel position of the second vertex # 2. In this example, as shown in FIG. 3B, the pixel position coordinate of the vertex pixel G2 is indicated by G2 (h2, v2). Thereafter, the pixel position of the third vertex # 3 is searched. In this example, as shown in FIG. 4A, the pixel position coordinate of the vertex pixel G3 is indicated by G3 (h3, v3). Then, the pixel position of the fourth vertex # 4 is searched. In this example, as shown in FIG. 4B, the pixel position coordinate of the vertex pixel G4 is indicated by G4 (h4, v4).

  Then, the process proceeds to step Q7, and the reading processing unit 81 performs pixel coordinates G1 (h1, v1) and G2 (h2, v2) of the first to fourth vertices of the HV image processing system shown in FIG. 5A. , G3 (h3, v3), G4 (h4, v4) are converted into position coordinates of the vertices A to D in the XY scanning system. For example, the pixel position coordinates G1 (h1, v1) of the first vertex pixel G1 shown in FIG. 3A are converted into position coordinates B (x2, y2) showing the vertex B as shown in FIG. 5A. Similarly, the pixel position coordinate G2 (h2, v2) of the second vertex pixel G2 is converted into a position coordinate A (x1, y1) indicating the vertex A. The pixel position coordinate G3 (h3, v3) of the third vertex pixel G3 is converted into a vertex position coordinate D (x4, y4) indicating the vertex D. The pixel position coordinates G4 (h4, v4) of the fourth vertex pixel G4 are converted into vertex position coordinates C (x3, y3) indicating the vertex C, respectively.

  Thereafter, the process proceeds to step Q8, where the inclination correction unit 82 compares the original paper image 20 'with a preset reference position, and executes a paper image inclination correction process with respect to the reference position. For example, the inclination correction unit 82 has pixel coordinates A (x1, y1), B (x2, y2), C (x3, y3), D (x4, 4) of the four vertices of the paper image obtained by the reading processing unit 81. The inclination angle θ of the paper image is corrected based on y4).

  At this time, according to the example shown in FIG. 5B, the four vertex position coordinates of the original paper image 20 ′ after the coordinate conversion = A (x1, y1), B (x2, y2), C (x3, y3), The inclination is obtained from D (x4, y4), and each is corrected. Here, correction is performed using a straight line of the line segment AC. For example, as shown in FIG. 5B, a matrix in the case of “no original paper inclination” is developed, and pixel values constituting the original paper image 20 ′ are described in each lattice point. In this example, the pixel value of the vertex A is described in the lattice point a, and the pixel value of the position advanced by one pixel from the coordinate A in the inclination direction of the line segment AB is described in the lattice point b.

  If the description process of such pixel values is continued, the result is equivalent to excluding the inclination angle θ, and each vertex of the matrix has four vertex position coordinates = A (x1, y1), B (x2, y2), Pixel values G1, G2, G3, and G4 relating to C (x3, y3) and D (x4, y4) are respectively described (graphic rotation processing). By this graphic rotation processing, one side of the paper image becomes parallel to the reference line that defines the reference position, and the inclination angle θ of the paper image with respect to the reference position is eliminated. Here, the vertices A to D of the original paper image 20 'after the inclination correction processing are rewritten as vertices A' to D 'as shown in FIG. In this example, the position coordinate of the vertex A ′ is A ′ (X1, Y1), the position coordinate of the vertex B ′ is B ′ (X2, Y2), and the position coordinate of the vertex C ′ is C ′ (X3, Y3). Y3), and the position coordinates of the vertex D ′ are D ′ (X4, Y4).

  In step Q9, the size detection unit 83 calculates the paper size of the document 20 based on the vertex coordinates A 'to D'. At this time, the size detection unit 83 calculates the length Lx = X2−X1 of the document 20 based on the position coordinates (X1, Y1) of the vertex A ′ and the position coordinates (X2, Y2) of the vertex B ′. Further, the width Wx = Y3-Y1 of the document 20 is calculated based on the position coordinates (X1, Y1) of the vertex A ′ and the position coordinates (X3, Y3) of the vertex C ′ (size detection processing). Information regarding the length Lx = X2-X1 and the width Wx = Y3-Y1 is the size data Dsz of the document 20.

  Then, the process proceeds to step Q10 in the flowchart shown in FIG. 13, and the CPU 25 stores the image data Din in the image memory 13 and notifies the paper feeding means 23 of the size data Dsz. At this time, the size data Dsz is transferred to the paper feed means 23 as a paper feed control signal Sf. Further, the image data Dout output from the above-described reading processing unit 81 is output to the compression / decompression IC 28 under the DRAM control of the IC 85. In the IC 28, the image data Dout is compressed. The compressed image data Dout is transferred to the image memory 13 under the DRAM control of the IC 85 and temporarily stored. Thereafter, the process proceeds to step Q12.

  If the automatic paper feed mode is set in step Q4 described above, the process proceeds to step Q11 to execute automatic document feed reading processing. For example, the document 20 fed out from the document placing unit 41 is conveyed by the downstream roller 43 so as to rotate in a U-shape. In the automatic paper feeding mode, the recording surface of the document 20 is placed upward on the document placement unit 41. The scanner unit 11 provided below the ADF 40 reads a document image.

  Thereafter, the process proceeds to step Q12, in which the paper feed unit 23 selects a paper feed tray for the original paper and performs paper feed processing. At this time, the paper feeding unit 23 compares the size of the paper 30 prepared in each of the paper feeding trays # 1 to # 5 with the paper size of the document 20 received from the CPU 25, and uses the comparison result as the paper feeding tray. When there is a paper 30 of the corresponding size, the operation is performed to select a paper feed tray that stores the paper 30 of the size. If there is no paper 30 of the corresponding size in the paper feed tray as a result of the comparison, an operation is performed to select a paper feed tray containing the paper 30 of the closest size.

  In step Q13, the CPU 25 executes an image forming process. At this time, the compressed image data Din stored in the image memory 13 is read from the compression memory 27. The image data Dout read from the compression memory 27 is output to the compression / decompression IC 28 under the DRAM control of the IC 85. In the IC 28, the image data Dout is expanded. The decompressed image data Dout is transferred to the image writing unit 60 under the DRAM control of the IC 85. In the image writing unit 60, the laser drive signal Sd is PWM-modulated based on the image data Dout.

  The laser drive signal Sd after the PWM modulation is output to the laser diode 70a. The laser diode 70a emits a laser beam having a predetermined intensity based on the laser drive signal Sd. The laser beam emitted from the laser diode 70a is scanned by the photoconductor drum 71 shown in FIG. Thereby, an electrostatic latent image based on the image data Dout is formed (written) on the photosensitive drum 71. The electrostatic latent image formed on the photosensitive drum 71 is developed by the toner member under the control of the printer control unit 70b. The electrostatic latent image is converted into a toner image by the developing device 73. The developed toner image is transferred to the paper 30 selected in the previous step and controlled to be fed by the paper feeding means 23. The toner image on the paper 30 is fixed by the fixing device 78. Thereafter, the sheet (image formed product) 30 on which the toner image is fixed is discharged onto a discharge tray 96 or the like.

  In step Q14, the CPU 25 determines whether the page related to the image forming process is the last page. At this time, if the CPU 25 determines that the page related to the image forming process is not the last page, the CPU 25 returns to step Q13 to repeat the image forming process. If it is determined that the page related to the image forming process is the last page, the process proceeds to step Q15.

  If the stop key is pressed in step Q2, the process proceeds to step Q15, and the CPU 25 determines whether to end the document reading process. For example, the CPU 25 detects the power-off information and ends the document reading process. If the power-off information is not detected, the process returns to step Q1 to repeat the above-described processing.

  As described above, according to the copying machine as the second embodiment of the present invention, the scanner function (scanner 100) of the present invention is applied. Therefore, a document 30 of a predetermined size is read by reading a document of an arbitrary size. When an original image is formed, an image is formed on a paper 30 having a size that matches the paper 30 size of the original even if the original is inclined with respect to the reference position.

  Accordingly, it is possible to prevent the original image from being formed and output on the paper 30 having a different size, or the original image being formed and output in a bent state. In addition, since the operation of aligning the document with the reference position as in the conventional method is not required, it is possible to save twice the trouble of resetting the document one by one when the document slightly deviates from the reference position. . Thereby, it is possible to provide a copying machine or the like in which the manuscript setting operation is simple.

  The present invention relates to a scanner that reads a document of an arbitrary size and outputs document image information and document sheet size information, a digital copying machine that forms an image on a predetermined sheet based on document image information and document sheet size information, It is extremely suitable when applied to a multifunction machine or the like.

1 is a conceptual diagram illustrating a configuration example of a scanner 100 as a first embodiment according to the present invention. (A)-(C) is a figure showing an example of image processing at the time of platen mode. (A) and (B) are diagrams showing examples of extracting the first and second vertices # 1 and # 2 of the document sheet image 20 'in the platen mode. (A) and (B) are diagrams showing examples of extracting the third and fourth vertices # 3 and # 4 of the document sheet image 20 'in the platen mode. (A) and (B) are diagrams showing an example (part 1) of correcting the inclination of the original paper image 20 ′ in the platen mode. It is a figure which shows the example 2 of the inclination correction | amendment of the original paper image 20 'at the time of a platen mode. 6 is a flowchart illustrating an example of reading a document by the scanner. It is a conceptual diagram which shows the structural example of the copying machine 200 for monochrome as 2nd Example which concerns on this invention. 3 is a block diagram illustrating a configuration example of a control system of the copying machine 200. FIG. (A) to (F) are conceptual diagrams showing examples of selection of the paper size in the paper supply means 23. 7 is a conceptual diagram illustrating a display example of a paper size selection screen PR1 on the operation panel 48. FIG. 6 is a flowchart illustrating an image forming example (part 1) in the copying machine. 6 is a flowchart illustrating an image forming example (No. 2) in the copying machine.

Explanation of symbols

11 Scanner unit (image reading means)
DESCRIPTION OF SYMBOLS 13 Image memory 14 Operation means 14 'Operation & control part 15 Control means 18 Display part 23 Paper feed means 25 Image control CPU (control means)
35 Paper Feeder 48 Operation Panel (Display Unit + Operation & Control Unit)
50 Platen cover (background medium)
60 Image Writing Unit 70 Image Forming Unit 80 Image Processing Unit 81 Reading Processing Unit (Image Detection Unit)
82 Inclination correction unit (correction means)
83 Size detector (calculation means)
100 Scanner (document reading device)
200 copier

Claims (8)

An apparatus for reading a document of an arbitrary size and outputting document image information and document paper size information,
A background medium having a color different from the paper color of the original and having a size larger than the paper size of the original;
An image reading unit that arranges a document with an image forming surface facing the background medium, scans the background medium including the image forming surface of the document, and acquires document image information;
Image detecting means for expanding the original image information acquired by the image reading means and detecting a paper image of the original that partitions the acquired image of the background medium;
Correction means for comparing the paper image of the document output from the image detection means and a preset reference position to correct the inclination of the paper image with respect to the reference position;
An original reading apparatus comprising: an arithmetic means for obtaining a vertex coordinate value of the paper image after being corrected by the correcting means and calculating a paper size of the original based on the vertex coordinate value. The computing means is
2. The document reading apparatus according to claim 1, wherein a size detection calculation process for obtaining a width and length of the sheet of the document from four vertex coordinate values of the corrected sheet image is executed. A method for reading original image information and original paper size information from an original of an arbitrary size,
Placing a document with an image forming surface facing the background medium having a color different from the paper color of the document and having a size larger than the paper size of the document;
Scanning the background medium including the image forming surface of the document placed on the background medium to obtain document image information;
A paper image of the original document that expands the acquired original image information and partitions the acquired image of the background medium, and
Comparing the detected paper image of the document with a preset reference position to correct the inclination of the paper image with respect to the reference position,
An original reading method comprising: obtaining vertex coordinates of the paper image after correction, and calculating a paper size of the original based on the vertex coordinates. An apparatus for reading a document of an arbitrary size and forming a document image on a sheet of a predetermined size,
A document reading device that reads the document and outputs document image information and document sheet size information;
Image forming means for forming a document image on a sheet of a predetermined size based on document image information and document sheet size information output from the document reader;
The document reading device includes:
A background medium having a color different from the paper color of the original and having a size larger than the paper size of the original;
An image reading unit that arranges a document with an image forming surface facing the background medium, scans the background medium including the image forming surface of the document, and acquires document image information;
Image detecting means for expanding the original image information acquired by the image reading means and detecting a paper image of the original that partitions the acquired image of the background medium;
Correction means for comparing the paper image of the document output from the image detection means and a preset reference position to correct the inclination of the paper image with respect to the reference position;
An image forming apparatus comprising: an arithmetic unit that obtains a vertex coordinate value of the paper image after being corrected by the correction unit, and calculates a paper size of the document based on the vertex coordinate value. The computing means is
5. The image forming apparatus according to claim 4, wherein a size detection calculation process for obtaining a width and a length of the paper of the original from four vertex coordinate values of the paper image after correction is performed. A paper feeding unit that feeds the predetermined size paper to the image forming unit;
The paper feeding means is
It has multiple paper feed trays that store paper of different sizes,
Receiving the document paper size information from the document reader;
The image forming apparatus according to claim 4, wherein the paper feed tray is selected based on the document paper size information. The paper feeding means is
Comparing the size of the paper prepared in the paper feed tray with the original paper size information received from the control means;
The image forming apparatus according to claim 6, wherein when there is no paper of a size corresponding to the paper feed tray as a result of the comparison, the paper feed tray storing the paper of the closest size is selected. Operating means operated to select the size of the paper prepared in the paper feeding means;
The image forming apparatus according to claim 6, further comprising: a display unit that displays a finished state of the original image on the sheet of the size selected by the operation unit.

Images