JP2010252088A - Image reader, and image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a standard document size for a document used as a reading object without increasing cost nor requiring an extra operation by a user for inputting document size information even when a failure part is detected in an LED as a light source. <P>SOLUTION: A scanner part includes a light source composed by connecting a plurality of LEDs to a drive circuit for each of a plurality of blocks arranged in a main scanning direction, and arranged at a position without including two or more document size changeover points in each of which each block corresponds to document width in the main scanning direction of a different standard document size. A document size calculation part 2111 calculates, as a size of a document of a reading object, a standard document size having document width of a document size changeover point included in a block where a failure is detected when a standard document size having a document width calculated by a document width calculation part 2110 does not exist and the failure is detected in any of the blocks by a failure detection part 2112. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image reading apparatus and an image forming apparatus, and more particularly to a technique for detecting the size of a document to be read.

  2. Description of the Related Art Conventionally, as a light source for an image reading apparatus, an LED array light source in which an LED group having advantages of low heat generation and low power consumption is proposed. This LED array light source is configured to be connected to the drive circuit for each block composed of a plurality of LEDs, so that when a malfunction occurs in the electrical system, a part that cannot be partially read occurs, but a halogen lamp or Unlike xenon tubes, the risk of all LED groups disappearing is reduced. For this reason, as shown in Patent Document 1 below, even when a faulty part is detected in some LEDs, the reading of the document that is the reading target at that time is sufficient for light irradiation other than the faulty part. Makes it possible to read a document by bringing the document to an area other than the failed part even if a failure part is detected in the LED as a light source, as shown in the following Patent Document 2 Technology has been proposed.

JP 2004-64406 A JP 2007-201952 A

  As in each of the prior arts described above, the size information of the document to be read is necessary to perform document reading when a failure of the LED as the light source is detected. However, as a method for determining the document size, (1) the document size is detected by a reflective sensor installed at the boundary where the document size is switched on the document reading table, and (2) document size information input from the user to the operation unit Have been proposed, or (3) the size of the original is determined by reading the original with a line sensor, but these require a special mechanism for acquiring the original size information. In addition, there is a problem that the cost is increased, or that the user is required to perform an extra operation for inputting document size information.

  The present invention has been made to solve the above problem, and even when a failure portion is detected in the LED as the light source, the document size information is input to the user without increasing the cost. An object of the present invention is to enable detection of a standard document size of a document to be read without requiring an extra operation.

According to the first aspect of the present invention, there is provided a transparent document table on which a document to be read is placed;
A plurality of LEDs arranged in the main scanning direction are connected to a drive circuit for each of a plurality of blocks arranged in the main scanning direction, and each of the blocks has a document size corresponding to a document width in the main scanning direction of a different standard document size. An image reading unit having a light source disposed at a position not including two or more switching points, and a photoelectric conversion element that reads an image of the document by irradiating the document placed on the document table by the light source When,
An original for calculating a change point where a pixel value forming an image of the original read by the image reading unit is greater than or equal to a predetermined value in the main scanning direction as an original width in the main scanning direction of the original A width calculator;
A document size calculator that calculates a standard document size having a document width calculated by the document width calculator;
A failure detection unit that detects whether or not a failure has occurred in the LED for each block;
The document size calculation unit detects a failure when a fixed document size having the calculated document width does not exist and a failure is detected in any one of the blocks by the failure detection unit. The image reading apparatus calculates a standard document size having a document width corresponding to the document size switching point included in the arranged position of the block as the document size of the document to be read.

  In the present invention, a plurality of LEDs are connected to a drive circuit for each of a plurality of blocks arranged in the main scanning direction, and each block does not include two or more document size switching points corresponding to document widths of different standard document sizes. When the document size calculation unit does not have a document size having the calculated document width and a failure is detected in any one of the blocks by the failure detection unit, The document size having the document width corresponding to the document size switching point included in the arrangement position of the block where the failure is detected is calculated as the standard document size of the document to be read. For this reason, the present invention fails even when the block located at the paper width end of the document to be read in the main scanning direction fails and a read image in the irradiation area by the block cannot be obtained. A standard document size having a document width indicated by a document size switching point included in the block can be detected. Accordingly, the present invention requires a separate mechanism such as a reflective sensor or requests the user to input document size information even when a defective portion is detected in the LED as the light source. Therefore, it is possible to detect the standard document size of the document to be read.

  The invention according to claim 2 is the image reading apparatus according to claim 1, wherein the document width calculation unit is a case where a block in which a failure has occurred is detected by the failure detection unit. Even when the change point exists in the pixel value forming the image of the document read by the image reading unit and located in the irradiation region of the block in which no failure is detected by the failure detection unit Calculates the change point as the document width in the main scanning direction of the document.

  According to the present invention, when the block in which the failure is detected by the failure detection unit does not include the change point, and the change point can be detected in an area of another block in which no failure is detected, the document width calculation unit Since the detected change point is calculated as the document width in the main scanning direction of the document to be read, even if a defective part is detected in the LED as the light source, It is possible to detect the standard document size of the existing document.

The invention according to claim 3 is the image reading apparatus according to claim 1 or 2, wherein the display unit displays operation guidance for the user,
An operation unit for receiving an input of a document reading instruction from a user;
If the document size of the document to be read is calculated by the document size calculation unit when the failure detection unit detects a block in which a failure has occurred, A determination unit that determines whether a width in the main scanning direction of a continuous irradiation region irradiated by the block is equal to or larger than a width of the calculated document size in the main scanning direction;
When the determination unit determines that the irradiation area is equal to or larger than the width of the detected document size in the main scanning direction, the display unit includes a block in which a failure has occurred or a block in which a failure has not occurred. A display control unit for displaying a message indicating
And a control unit that causes the image reading unit to read an image of the document whose document size is detected when the input of the document reading instruction is accepted by the operation unit after the message is displayed. is there.

  According to the present invention, the width in the main scanning direction of the continuous irradiation region irradiated by each block in which no failure has occurred is equal to or larger than the main scanning direction width of the calculated document size. When it is determined that the display control unit displays a message indicating a block in which a failure has occurred or a block in which no failure has occurred on the display unit, the user visually recognizes the message, Even if a defective part is detected in the LED as a light source by changing the document placement position to a position on the document table corresponding to the irradiation area where no failure has occurred, Calculation of a standard document size and image reading of a document to be read can be executed without requiring a separate mechanism or requesting the user to input document size information.

  According to a fourth aspect of the present invention, in the image reading apparatus according to the third aspect, the display control unit is configured such that the irradiation area is equal to or larger than a width in a main scanning direction of the document size detected by the determination unit. If it is determined that the document size is not, a message indicating that the image cannot be read for the document whose document size is detected is displayed on the display unit.

  According to the present invention, when the determination unit determines that the irradiation area is not equal to or larger than the width of the detected document size in the main scanning direction, the display control unit determines whether the document size is detected. Since the message indicating that the image cannot be read is displayed on the display unit, depending on the image reading unit in which the failure has occurred, the user can recognize that the image of the document to be read cannot be read. be able to.

According to a fifth aspect of the present invention, there is provided the image reading device according to any one of the first to fourth aspects;
An image forming apparatus including an image forming unit that forms an image based on a document image read by the image reading apparatus.

  According to this invention, the effect obtained by the invention according to any one of claims 1 to 4 can be obtained.

  According to the present invention, even when a failure portion is detected in the LED as the light source, without incurring an increase in cost, without requiring an extra operation for inputting document size information to the user, It is possible to detect a standard document size for a document to be read.

1 is a longitudinal sectional view schematically showing an internal configuration of a multifunction machine according to an embodiment. It is a figure which shows schematic structure of the LED array light source of a scanner part. It is a figure which shows the relationship between each block of a LED array light source, and a fixed document size. 1 is a schematic side view showing an image reading apparatus of a multifunction machine. 1 is a block diagram illustrating a schematic configuration of an image reading circuit of an image reading apparatus. It is a block diagram which shows the internal structure of a document size calculation part, a failure detection part, and a shading correction part. It is a figure which shows the example of the sample data of a white reference value. 6 is a diagram illustrating an example of pixel value sample data in image reading performed when a document size is detected by a scanner unit. FIG. 6 is a flowchart illustrating processing during an image reading operation performed by a scanner unit of the multifunction peripheral. 6 is a flowchart illustrating processing during an image reading operation performed by a scanner unit of the multifunction peripheral. 6 is a diagram illustrating an example of pixel value sample data in image reading performed when a document size is detected by a scanner unit. FIG. It is a figure which shows the positional relationship of the original document mounted on the contact glass, and each block of a light source. It is a figure which shows the positional relationship of the original document mounted on the contact glass, and each block of a light source. It is a figure which shows the positional relationship of the original document mounted on the contact glass, and each block of a light source.

  Hereinafter, an image reading apparatus and an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiment, an example in which the image reading apparatus and the image forming apparatus according to the present invention are integrated into a multifunction machine having functions such as a color copy, a scanner, a facsimile, and a printer will be described.

  FIG. 1 is a longitudinal sectional view schematically showing the internal configuration of the multifunction machine 1 according to the present embodiment. FIG. 2 is a diagram showing a schematic configuration of the LED array light source of the scanner unit. FIG. 3 is a diagram showing the relationship between each block of the LED array light source and the standard document size.

  The multifunction device 1 is roughly composed of an image reading device 2 and a device body 3. The image reading apparatus 2 includes a document feeding unit (document feeding unit) 21 and a scanner unit 22. The document feeder 21 implements ADF, and includes a document tray 241, a sheet feed roller 232, a transport drum 233, a sheet discharge roller 234, and a sheet discharge tray 235. The document tray 241 is a place where the document is placed. The documents placed on the document tray 241 are taken one by one by the paper feed roller 232 and conveyed to the conveyance drum 233. The document that has passed through the transport drum 233 is discharged to a discharge tray 235 by a discharge roller 234.

  A scanner unit (an example of an image reading unit) 22 optically reads an image of a document and generates image data. The scanner unit 22 is provided in the apparatus main body 3. The scanner unit 22 includes a contact glass 221, a light source 222, a first mirror 223, a second mirror 224, a third mirror 225, a first carriage 226, a second carriage 227, an imaging lens 228, and a CCD (Charge Coupled Device) 229. Prepare. The scanner unit 22 uses an LED array light source as the light source 222, and the first mirror 223, the second mirror 224, the third mirror 225, the first carriage 226, the second carriage 227, and the imaging lens 228, from the document. Is guided to the CCD 229.

  As shown in FIG. 2, the scanner unit 22 includes, as a light source 222, a plurality of LEDs 220 arranged in the main scanning direction and a DC-DC converter 2221 for each of the plurality of blocks A to E arranged in the main scanning direction. And an LED array light source connected to a driving circuit such as a low current driving circuit 2222. The low current drive circuit 2222 is connected to a control unit 2115 described later. In the light source 222, each of the blocks A to E includes 12 LEDs. The low current drive circuit 2222 is connected to a control unit 2115 described later. In the present embodiment, an example is shown in which the light source 222 includes a LED whose size in the main scanning direction is 5 mm. In this case, each of the blocks A to E includes 12 LEDs.

  In the present embodiment, as shown in FIG. 3, each of the blocks B to E includes one document size switching point corresponding to the document width of the standard document size in the main scanning direction in the document reading area. Arranged in position. For example, each of the blocks A to E is juxtaposed in the main scanning direction with a width of 6 cm in the main scanning direction. By setting the width in the main scanning direction of each of the blocks A to E in this way, the block E has a document size corresponding to a document width of A3 size 297 mm (297 mm × 420 mm) which is an A size (mm) of a standard paper. Block D includes a document size switching point corresponding to a document width of A4 size 210 mm (210 mm x 297 mm), and block C includes a document size switching point corresponding to a document width of A5 size 148 mm (148 mm x 210 mm) The block B includes a document size switching point corresponding to a document width of 105 mm (105 mm × 148 mm) of A6 size.

  The CIS 231 is provided downstream of the scanner unit 22 in the document conveyance direction. The CIS 231 is provided at a position where the surface opposite to the document surface read by the scanner unit 22 can be read in the document transport path.

  A contact glass (an example of a document table in the claims) 221 is a place for placing a document. The document feeder 21 is attached to the upper surface edge of the apparatus body 3 (the back side in the drawing in FIG. 1) so as to be rotatable in the contact / separation direction with respect to the contact glass 221. In the flatbed reading mode described later, the user rotates the document feeder 21 in a direction away from the contact glass 221 to expose the contact glass 221.

  The light source 222 and the first mirror 223 of the scanner unit 22 are supported by the first carriage 226, and the second mirror 224 and the third mirror 225 are supported by the second carriage 227.

  As an original reading method of the image reading apparatus 2, there are a flat bed reading mode in which the scanner unit 22 reads an original placed on the contact glass 221 and an ADF reading mode in which the original is taken in by ADF and the original is read during the conveyance. is there.

  In the flat bed reading mode, the light source 222 irradiates a document placed on the contact glass 221, and reflected light for one line in the main scanning direction is reflected in the order of the first mirror 223, the second mirror 224, and the third mirror 225. Then, the light enters the imaging lens 228. The light incident on the imaging lens 228 is imaged on the light receiving surface of the CCD 229. The CCD 229 is a one-dimensional image sensor, and simultaneously processes a document image for one line. When the reading for one line is completed, the first carriage 226 and the second carriage 227 are moved in the direction orthogonal to the main scanning direction (sub-scanning direction, arrow Y direction), and the next line is read.

  In the ADF reading mode, the originals placed on the original tray 241 are taken one by one by the paper feed roller 232, and the originals are placed on the image reading position 230 provided in the conveyance path from the conveyance drum 233 to the paper discharge tray 235. When passing, the light source 222 irradiates the document, and the reflected light for one main scanning line is reflected in the order of the first mirror 223, the second mirror 224, and the third mirror 225, and enters the imaging lens 228. The light incident on the imaging lens 228 is imaged on the light receiving surface of the CCD 229. Subsequently, the document is conveyed by the document feeder 21 and the next line is read. In the following description, those not specifically described will be described on the assumption that an original is automatically fed in the flatbed reading mode and an image is read.

  Further, the document feeder 21 has a document reversing mechanism including a switching guide 236, a reversing roller 237, and a reversing conveyance path 238. The original whose surface (one side of the original) is read by the first ADF reading is reversed using the original reversing mechanism and conveyed again, so that the CCD 229 reads the back side (the other side of the original) again. Can be done. This document reversing mechanism operates only when reading both sides, and does not operate when reading one side. After reading the back side during single-sided reading and double-sided reading, the switching guide 236 is switched to the upper side, and the document that has passed through the transport drum 233 is discharged onto the discharge tray 235 by the discharge roller 234. After the surface reading at the time of double-sided reading, the switching guide 236 is switched to the lower side, and the document that has passed through the conveying drum 233 is conveyed to the nip portion of the reversing roller 237. Thereafter, the switching guide 236 is switched upward and the reversing roller 237 rotates in the reverse direction, whereby the document is re-conveyed to the conveying drum 233 via the reverse conveying path 238.

  Further, in the ADF reading mode, the image reading apparatus 2 according to the present embodiment causes the CCD 229 to read the front surface of the document while the document is being conveyed as described above, and at the same time reads the back side of the document by the CIS 231. Can be performed. That is, the front side of the original fed from the original tray 241 is read by the CCD 229 when passing over the image reading position 230, and the back side is read when passing through the CIS 231. By using the CCD 229 and the CIS 231 in this way, it is possible to read both sides of a document with one pass.

  The multifunction device 1 includes an apparatus main body 3 and a stack tray 6 disposed on the left side of the apparatus main body 3. The apparatus main body 3 includes a plurality of paper feed cassettes 461, a paper feed roller 462 that feeds sheets (recording media) one by one from the paper feed cassette 461 and conveys them to the recording unit (image forming unit) 40, and a paper feed cassette 461. And a recording unit 40 that forms an image on the sheet conveyed from the printer. Further, a manual feed tray 471 is provided. From this manual feed tray 471, paper of a size that is not stored in any paper feed cassette, paper on which an image is already formed on one side (back paper), or an OHP sheet is provided. An arbitrary recording medium can be placed, and is fed into the apparatus main body 3 one by one by a paper feed roller 472.

  The recording unit 40 is based on a charge eliminating device 421 that removes residual charges from the surface of the photosensitive drum 43, a charging device 422 that charges the surface of the photosensitive drum 43 after charge removal, and image data acquired by the scanner unit 22. The laser beam is output to expose the surface of the photosensitive drum 43, and an exposure device 423 that forms an electrostatic latent image on the surface of the photosensitive drum 43, and on the photosensitive drum 43 based on the electrostatic latent image, Developing devices 44C, 44M, 44Y, and 44K that form toner images of each color of cyan (C), magenta (M), yellow (Y), and black (K), and toner images of each color that are formed on the photosensitive drum 43 A transfer drum 49 on which toner images are transferred, a transfer device 41 that transfers the toner image on the transfer drum 49 to a sheet, and a sheet on which the toner image has been transferred is heated to set the toner image on the sheet. And a fixing device 45 for. Note that toner is supplied to each color of cyan, magenta, yellow, and black from a toner supply container (toner cartridge) (not shown). Further, conveyance rollers 463 and 464 that convey the sheet that has passed through the recording unit 40 to the stack tray 6 or the discharge tray 48 are provided.

  When images are formed on both sides of a sheet, after the recording unit 40 forms an image on one side of the sheet, the sheet is nipped by a conveyance roller 463 on the discharge tray 48 side. In this state, the transport roller 463 is rotated in the reverse direction to switch back the paper, and the paper is sent to the paper transport path L to be transported again to the upstream area of the recording unit 40. The recording unit 40 forms an image on the other surface. Then, the paper is discharged to the stack tray 6 or the discharge tray 48.

  Further, in front of the apparatus main body 3, a display unit 51 that allows a user to visually recognize an operation screen and various messages, and an operation unit 5 having operation buttons for inputting various operation commands are provided. . The operation unit 5 includes a display unit 51 including a touch panel, a numeric key group 53, a start button 55, and the like. The display unit 51 is configured by an LCD (Liquid Crystal Display), an ELD (Electronic Luminescent Display), or the like, and displays selection screens such as paper size selection, magnification selection, and density selection.

  Next, an operation of acquiring the black reference value and the white reference value for shading correction by the scanner unit 22 and the CIS 231 will be described. FIG. 4 is a schematic side view showing the image reading device 2 of the multifunction machine 1.

  In the image reading apparatus 2 of the present embodiment, a white reference plate (white reference member) 10 is provided at a position that is out of the image reading position 230 and that can be read by the scanner unit 22. The white reference plate 10 is a white belt-like member attached to the contact glass 221 so as to extend in the main scanning direction (a direction orthogonal to the paper surface in FIG. 4). When the scanner unit 22 acquires a white reference value for shading correction, the first carriage 226 and the second carriage 227 move to the position of the white reference plate 10 in the sub-scanning direction, and the white color of the white reference plate 10 is moved by the light source 222. The white surface is read with the surface illuminated. When the scanner unit 22 acquires the black reference value for shading correction, the first carriage 226 and the second carriage 227 are similarly moved to the position of the white reference plate 10, the light source 222 is turned off, and the white reference plate 10 is turned off. The white surface is read in a state where the white surface is not irradiated.

  Next, an image reading circuit for the image reading device 2 in the multifunction machine 1 will be described. FIG. 5 is a block diagram illustrating a schematic configuration of the image reading circuit of the image reading apparatus 2. The image reading circuit 210 of the image reading apparatus 2 includes a CPU 211, a RAM 212, a ROM 213, an A / D conversion unit 217, a shading correction unit 218, and an image processing unit 219. These units are communicably connected to each other via a bus BUS.

  The CPU 211 is a control circuit for managing overall operation control of the multifunction machine 1. The CPU 211 performs a document width calculation unit 2110, a document size calculation unit 2111, a failure detection unit 2112, a determination by an operation according to the operation control program of the MFP 1 and the image reading device 2 stored in the ROM 212 or the HDD (not shown). Functions as a unit 2113, a display control unit 2114, and a control unit 2115.

  The document width calculation unit 2110 changes the pixel value forming the image of the document read by the scanner unit 22 by more than a predetermined value (for example, pixel value 128 in the case of monochrome binary data) in the main scanning direction. Is calculated as the document width in the main scanning direction of the document.

  The document size calculation unit 2111 calculates a standard document size having the document width calculated by the document width calculation unit 2110.

  The failure detection unit 2112 detects, for each block, whether or not a failure has occurred in the LED that constitutes the light source 222. Details of the failure detection processing by the failure detection unit 2112 will be described later.

  When the failure detection unit 2112 detects a faulty block and the document size calculation unit 2111 calculates the document size of the document to be read, the determination unit 2113 generates a failure. It is determined whether or not the width in the main scanning direction of the continuous irradiation region irradiated by each block that is not set is equal to or larger than the width of the calculated document size in the main scanning direction.

  The display control unit 2114 controls display control of the display unit 51. For example, when the determination unit 2113 determines that the irradiation area is equal to or larger than the area of the document size calculated by the document size calculation unit 2111, the display control unit 2114 changes the orientation of the document to the display unit 51. Display a message prompting.

  The control unit 2115 is responsible for overall operation control of the multifunction machine 1 and is also responsible for operation control of the image reading apparatus 2. For example, after the message is displayed, the control unit 2115 receives an instruction for causing the scanner unit 22 to read the document to the operation unit 5 and performs an image reading operation on the document in which the document size is detected. In addition, it controls the operation of the scanner 22 and the drive mechanism such as the CIS 231 necessary for performing the image reading operation for acquiring the white reference value for shading correction and the white reference value.

  The RAM 212 is a storage mechanism used as a work area when controlling the operations of the multifunction machine 1 and the image reading apparatus 2 according to the operation control program by the CPU 211.

  The ROM 213 stores the operation control program and the like.

  The operation unit 5 receives various operation instructions such as a copy operation start instruction from the operator.

  The A / D conversion unit 217 converts read image data composed of analog electric signals sent from the CCD 229 and the CIS 231 of the scanner unit 22 into digital read image data. Further, the A / D conversion unit 217 outputs the read image data after the digital conversion to the shading correction unit 218.

  The shading correction unit 218 uses the white reference value and the black reference value acquired by the reading operation of the white reference plate 10 by the scanner unit 22 and the reading operation of the shading roller 11 by the CIS 231, respectively. The shading correction is performed on each original image read in step (b). The shading correction unit 218 sends the data of the document image after the shading correction to the image processing unit 219.

  The image processing unit 219 performs various types of image processing on the shading-corrected image data sent from the shading correction unit 218. For example, the image processing unit 219 performs image processing such as level correction and gamma correction, image data compression or expansion, and enlargement or reduction on the image data.

  Next, the internal configuration of the document size calculation unit 2111, the failure detection unit 2112, and the shading correction unit 218 will be described. FIG. 6 is a block diagram showing the internal configuration of the document size calculation unit 2111, the failure detection unit 2112, and the shading correction unit 218. FIG. 7 is a diagram illustrating an example of white reference value sample data. FIG. 8 is a diagram illustrating an example of pixel value sample data in image reading performed when the scanner unit detects the document size.

  The shading correction unit 218 includes a black reference memory 2181, a white reference memory 2182, and a shading correction circuit 2185.

  The black reference memory 2181 stores the black reference value B (n) for shading correction acquired by the scanner unit 22 and the CIS 231.

  The white reference memory 2182 stores the white reference value W (n) for shading correction acquired by the scanner unit 22 and the CIS 231.

  The shading correction circuit 2185 is read by the scanner unit 22 or the CIS 231 using the black reference value and the white reference value acquired by the reading operation of the white reference plate 10 by the scanner unit 22 or the reading operation of the shading roller 11 by the CIS 231. Shading correction is performed on the original image. For example, in the case of 256 gradations, the shading correction circuit 2185 performs image processing using the following equation (1) to calibrate image data. The actual input data is actual document image data read by the scanner unit 22 or the CIS 231. The input image data value (I_out) is the document image data after shading correction. The actual input data (I_in) is data of an original image read by the scanner unit 22 or the CIS 231.

Input image data value (I_out) = 256 x (actual input data (I_in)-black reference value B (n)) ÷ (white reference value W (n)-black reference value B (n)) ... Formula (1)
The failure detection unit 2112 performs an abnormality detection and an abnormal position detection of the LED group provided in the LED array light source as the light source 222 provided in the scanner unit 22 at the time of shading correction at the time of image reading by the shading correction unit 218. When the white reference value W (n) for shading correction is acquired by the scanner unit 22 at the time of shading correction, if any of the blocks A to E constituting the light source 222 is abnormal, the white reference value W (n) shows the distribution of sample data as shown in FIG. That is, among the blocks A to E, in the irradiation area by the failed block, the luminance data of the area falls due to insufficient light amount due to LED non-lighting (in FIG. The case where irradiation by the LED group of the block D is not performed is shown). The failure detection unit 2112 obtains the sample data from the scanner unit 22 and compares the sample data with a predetermined value (threshold value A). Detects a block in which a lighting state, deterioration, or failure occurs. Here, the predetermined threshold A is a value (eg, luminance 200) that guarantees sufficient luminance so that the output image is not output as a black stripe or a white stripe. The failure detection unit 2112 stores the detected block name in a built-in memory.

  The document width calculation unit 2110 reads a document to be read that is placed on the contact glass 221 by the scanner unit 22 under the control of the control unit 2115 immediately before the document feeding unit 21 is closed during flatbed mode reading. Is read for one or more predetermined lines for document size detection, the scanned image of the document is acquired from the scanner unit 22, and the pixel value forming the image of the document is the main scanning direction. , Based on the pixel values from the first pixel arranged first in the main scanning direction to the last pixel (in the case of reading in a plurality of lines, the average value in a plurality of lines at the same pixel position in the main scanning direction). Thus, the change point as shown in FIG. 8 is detected, and the distance from the first pixel position arranged in the main scanning direction to the position of the pixel located at the change point is defined as the main scanning direction of the document. Is calculated as the document width at.

  The document size calculation unit 2111 includes a document width information storage unit 2141 and a document size detection unit 2143.

  The document width information storage unit 2141 stores document width information in the main scanning direction corresponding to each of a standard document size (specified document size) according to vertical and horizontal directions such as A size and B size. In the present embodiment, in order to detect the A-size vertical standard document size, it is sufficient to store the document width information in the main scanning direction corresponding to the A-size vertical standard document size.

  The document size detection unit 2143 reads the document size having the document width in the main scanning direction calculated by the document width calculation unit 2110 from the document width information storage unit 2141, and sets the read document size as the reading target. Is detected as the size of the original. Further, the document size detection unit 2143 does not have the document size having the document width calculated by the document width calculation unit 2110 in the document width information storage unit 2141, and the failure detection unit 2112 forms a plurality of the blocks constituting the light source 222. When a failure is detected in any one of the blocks, the document size corresponding to the document width corresponding to the document size switching point included in the arrangement position of the block in which the failure is detected is set as the reading target. This is detected as the original size of the original.

  Next, an image reading operation by the scanner unit 22 of the multifunction machine 1 will be described. FIG. 9 and FIG. 10 are flowcharts showing processing at the time of image reading operation by the scanner unit 22 of the multifunction machine 1. FIG. 11 is a diagram illustrating an example of pixel value sample data in image reading performed when a document size is detected by the scanner unit. 12 to 14 are views showing the positional relationship between the document placed on the contact glass and each block of the light source.

  When the copying operation is started in the multifunction device 1 based on an instruction from the user and shading correction is performed, the shading data of the white reference value W (n) and the black reference value B (n) is acquired by the scanner unit 22. Then (S1), the failure detection unit 2112 determines whether all the white reference values W (n) for the pixels arranged in the main scanning direction are equal to or greater than the threshold A (S2). That is, the failure detection unit 2112 detects whether or not a failure such as non-lighting has occurred in each of the blocks A to E of the LED group constituting the light source 222 based on the white reference value W (n).

  If the failure detection unit 2112 determines that the white reference values W (n) of the pixels arranged in the main scanning direction are all equal to or greater than the threshold A (YES in S2), the control unit 2115 performs a normal copy operation. Is executed (S18). That is, since the failure detection unit 2112 determines that no failure has occurred in each block of the LED group constituting the light source 222, a normal copy operation is performed.

  On the other hand, when the failure detection unit 2112 determines that there is an area indicating a pixel value having a value less than the threshold A among the white reference values W (n) of the pixels arranged in the main scanning direction (NO in S2). The display control unit 2114 causes the display unit 51 to display a message prompting the user to input an instruction as to whether or not to continue the copy operation (S3). In this embodiment, as shown in FIG. 2, each LED group of the light source 222 is connected to the drive circuit for each of a plurality of blocks, and thus a defect such as a non-lighting state occurs in one LED. In such a case, all the LEDs belonging to the block including the LED causing the malfunction are not lit, and the LEDs belonging to the block not including the LED causing the malfunction are kept lit. For this reason, as shown in FIG. 7, the brightness value of the white reference value W (n) falls due to insufficient light quantity due to LED non-lighting in the pixel value of the portion corresponding to the irradiation area of the failed block.

  After the message is displayed, when the user inputs an instruction not to continue the copy operation by operating the start button 55 or the like (NO in S4), the subsequent document image reading operation and the recording unit by the scanner unit 22 are performed. The image forming operation by 40 is not performed. The display control unit 2114 causes the display unit 51 to display a message indicating a serviceman call that prompts the user to request a repair to the maintenance work (S19).

  In addition, after the message is displayed, if the user inputs a copy operation continuation instruction by operating the start button 55 or the like (YES in S4), the display control unit 2114 displays the standard size document for the user. Is displayed on the display unit 51 (S5). Here, the reason for prompting the placement of the standard-size document is that any of the blocks A to E of the light source 222 is out of order, so that the free-size document is placed on the contact glass 221 and placed. This is because the width of the placed document cannot be calculated, and the document size cannot be calculated.

  Then, the control unit 2115 causes the scanner unit 22 to read the image of the placed document in order to acquire document size detection data (S6). The control unit 2115 causes the scanner unit 22 to read the document with the light source 222 turned on. At this time, as described above, the control unit 2115 causes the scanner unit 22 to read an image of only one scanning line, and the pixel value of the pixel forming the scanned image for the one scanning line is used as the document size detection data. Alternatively, the control unit 2115 may cause the scanner unit 22 to read an image for a plurality of scanning lines, and the average value of the pixel values forming the read image for the plurality of scanning lines may be used as the document size detection data. Good.

  Thereafter, the document width calculation unit 2110 has pixels whose pixel values forming the image of the document read by the scanner unit 22 are first to last pixels arranged in the main scanning direction in the main scanning direction. Based on the value, the distance from the first pixel in the main scanning direction to the pixel serving as the change point is calculated as the document width in the main scanning direction of the document (S7).

  Subsequently, the document size detection unit 2143 determines whether or not a document size having the document width calculated by the document width calculation unit 2110 is stored in the document width information storage unit 2141 (S8). In this embodiment, it is assumed that the document width information storage unit 2141 stores A-size portrait document size information, and the multifunction device 1 detects the A-size portrait document size. If a document size having the calculated document width is stored in the document width information storage unit 2141 (YES in S8), the document size detection unit 2143 sets the document size as the reading target. It is detected as the document size of the document being scanned (S17).

  In addition, when the document size having the document width calculated by the document width calculation unit 2110 does not exist in the document width information storage unit 2141 (NO in S8), the document size detection unit 2143 performs the failure detection unit 2112 in S2. Based on the detected failure detection result (sample data distribution of the white reference value W (n) as shown in FIG. 7), it is determined which block A to E is the block in which the failure has occurred. At the same time, it is detected whether there is only one defective block (S9). When the document size detection unit 2143 detects that there is only one defective block (YES in S9), the document size detection unit 2143 corresponds to the document size switching point included in the arrangement position of the block in which the failure is detected. A document size having a document width is read from the document width information storage unit 2141 and the read document size is detected as the document size of the document to be read (S10).

  When the document size detection unit 2143 detects that there are a plurality of failed blocks (NO in S9), the display control unit 2114 sends a repair request for maintenance work to the display unit 51 to the user. A message indicating the urgent serviceman call is displayed (S19).

  For example, when a failure has occurred in any one of the blocks A to E of the light source 222, as shown in FIG. 11, the change point is adjacent to the block in which the failure is detected and the block. It appears as the pixel value of the pixel located at the boundary of the current block. In this example, FIG. 11 shows a case where the block D is faulty. Here, in the present embodiment, each of the blocks B to E is set so as to include an original width point corresponding to one standard size in the main scanning direction. , The A size vertical document size information corresponding to the document width is not stored in the document width information storage unit 2141. At this time, if the above change point does not appear in the pixel values of the irradiation areas by the blocks A to C and the pixel values of the irradiation areas by the block E, the size of the document placed on the contact glass 221 is A size. It is assumed that the document size is a vertical standard document size, and if the document size corresponding to the document width is not stored in the document width information storage unit 2141, a true change indicating the document width of the document to be read The point is not a change point shown in FIG. 11 but is likely to be a document size switching point included in the failed block. Therefore, in this example, the document size detection unit 2143 is a case where a failure has occurred in any of the blocks A to E of the light source 222, and the document size corresponding to the calculated document width. Is not stored in the document width information storage unit 2141, the document size of the document to be read is a standard document size having a document width corresponding to the document size switching point included in the failed block. That is, it detects that it is A4 vertical size.

  Further, the determination unit 2113 determines whether or not a document having the detected document size can be read only by the LED group of the block in which no failure has occurred in the light source 222 (S11). For example, as shown in FIG. 12, when the block D of the light source 222 is broken, an A4 vertical document detected in the processes of S9 and S10 is a non-irradiated area due to the failed block D. Therefore, it is impossible for the scanner unit 22 to read a normal document image. However, as shown in FIG. 13, when the block B of the light source 222 is faulty and the A6 vertical size is detected in the processes of S9 and S10, the original is read by the faulty block B. Although a part is the non-irradiated region R, a normal document image can be read by the scanner unit 22 by changing the placement position of the document on the contact glass 221 to the irradiated regions of the other blocks C and D. It becomes possible. For this reason, the determination unit 2113 determines whether or not the document having the detected document size can be read only by the LED group of the block in which the failure in the light source 222 has not occurred.

  Specifically, in the main scanning direction, the determination unit 2113 determines that the width in the main scanning direction of the continuous irradiation area irradiated by each block in which no failure has occurred is the main scanning direction of the detected document size. By determining whether or not the width is greater than or equal to the width, it is determined by the scanner unit 22 in the above state whether or not an image of the document that is to be read at this time can be read.

  If the determination unit 2113 determines that the width of the continuous irradiation area in the main scanning direction is equal to or larger than the width of the detected document size in the main scanning direction (YES in S11). The display control unit 2114 causes the display unit 51 to display a message that prompts the user to change the document placement position on the contact glass 221 (S12). In this case, the determination unit 2113 stores the arrangement position information in the main scanning direction for each of the blocks A to D, and is a continuous irradiation region by each block in which no failure has occurred. It is detected which of the blocks A to D is a block that forms an irradiation area that is equal to or larger than the width of the detected document size in the main scanning direction. In S12, the display control unit 2114 detects the block. The displayed block is preferably displayed on the display unit 51 together with the message. In addition, the determination unit 2113 detects a failed block or a non-failed block among the blocks A to D, or both of them, and the display control unit 2114 detects the failed block or failure. The blocks that are not used and both of them may be displayed on the display unit 51 as the message.

  After the display of the message in S12, when the copy operation execution instruction is input again by the user operating the start button 55 (YES in S13), the control unit 2115 receives from the paper feed cassette 461, the manual feed tray 471, and the like. The size of the original fed by the paper feeding mechanism is set to the detected original size (S14). The control unit 2115 scans the document image by the scanner unit 22 by irradiation with a block forming a continuous irradiation region that is equal to or larger than the width of the detected document size in the main scanning direction. 22 is set, an image reading operation by the scanner unit 22 and an image forming operation by the recording unit 40 are performed (S15). However, in S15, the control unit 2115 causes the scanner unit 22 to irradiate all of the blocks A to D to read the original image, and the image processing unit 219 forms the continuous irradiation region. It is also possible to extract only the original image read in the irradiation area by the block being used, and use the extracted image data as image data for the image forming operation by the recording unit 40.

  If the copy operation execution instruction is not input again by the user operating the start button 55 after displaying the message in S12 (NO in S13), the subsequent document image reading operation by the scanner unit 22 and the image by the recording unit 40 are performed. No forming operation is performed.

  If the determination unit 2113 determines that the width of the continuous irradiation area in the main scanning direction is not equal to or larger than the width of the detected document size in the main scanning direction (NO in S11), the detection is performed. Since the current scanner unit 22 cannot read the original image of the original size, the display control unit 2114 causes the display unit 51 to display a message indicating that the original cannot be read (S16). ). After the process of S16, after it is determined NO in S13, the display control unit 2114 causes the display unit 51 to display a message indicating the above-mentioned surviving man call (S19).

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, in the above embodiment, detection of A size vertical size has been described as an example, but the number of blocks of the light source 222 is increased, each block width is shortened, and the main scanning direction corresponding to each size of A size vertical Each block for all document width information consisting of document width information in the main scanning direction corresponding to each size of B size, and each document width information in the main scanning direction of other sizes. Each block is arranged so as not to include two or more document width information, and the document width information storage unit 2141 is provided for each of A size vertical size, B size vertical size, and other standard document sizes. By storing the corresponding document width information in the main scanning direction, calculation of the document width in the main scanning direction for A size portrait, B size portrait, and other sizes, and thus A size portrait, B size portrait, Still other services It is possible to calculate the size of the original document.

DESCRIPTION OF SYMBOLS 1 Multifunctional device 2 Image reader 22 Scanner part 222 Light source 2221 Converter 2222 Low current drive circuit 40 Recording part 51 Display part 55 Start button 210 Image reading circuit 211 CPU
2110 Document width calculation unit 2111 Document size calculation unit 2112 Failure detection unit 2113 Determination unit 2114 Display control unit 2115 Control unit 2141 Document width information storage unit 2143 Document size detection unit 218 Shading correction unit 219 Image processing unit 221 Contact glass A to E blocks

Claims (5)

A transparent document table on which a document to be read is placed;
A plurality of LEDs arranged in the main scanning direction are connected to a drive circuit for each of a plurality of blocks arranged in the main scanning direction, and each of the blocks has a document size corresponding to a document width in the main scanning direction of a different standard document size. An image reading unit having a light source disposed at a position not including two or more switching points, and a photoelectric conversion element that reads an image of the document by irradiating the document placed on the document table by the light source When,
An original for calculating a change point where a pixel value forming an image of the original read by the image reading unit is greater than or equal to a predetermined value in the main scanning direction as an original width in the main scanning direction of the original A width calculator;
A document size calculator for calculating a standard document size having a document width calculated by the document width calculator;
A failure detection unit that detects whether or not a failure has occurred in the LED for each block;
The document size calculation unit detects a failure when a fixed document size having the calculated document width does not exist and a failure is detected in any one of the blocks by the failure detection unit. An image reading apparatus that calculates a standard document size having a document width corresponding to the document size switching point included in the arranged position of the block as the document size of the document to be read.   The document width calculation unit is a pixel value that forms an image of a document read by the image reading unit, even when a failure block is detected by the failure detection unit. The change point is calculated as a document width in the main scanning direction of the document when the change point exists in a pixel value located in an irradiation area of a block in which no failure is detected by the detection unit. The image reading apparatus described. A display unit for displaying operation guidance for the user;
An operation unit for receiving an input of a document reading instruction from a user;
If the document size of the document to be read is calculated by the document size calculation unit when the failure detection unit detects a block in which a failure has occurred, A determination unit that determines whether a width in the main scanning direction of a continuous irradiation region irradiated by the block is equal to or larger than a width of the calculated document size in the main scanning direction;
When the determination unit determines that the irradiation area is equal to or larger than the width of the detected document size in the main scanning direction, the display unit includes a block in which a failure has occurred or a block in which a failure has not occurred. A display control unit for displaying a message indicating
And a control unit that causes the image reading unit to read an image of the document in which the document size is detected when the input of the document reading instruction is received by the operation unit after the message is displayed. The image reading apparatus according to claim 1.   When the determination unit determines that the irradiation area is not greater than the width of the detected document size in the main scanning direction, the display control unit cannot read an image of the document in which the document size is detected. The image reading apparatus according to claim 3, wherein a message to the effect is displayed on the display unit. An image reading apparatus according to any one of claims 1 to 4,
An image forming apparatus comprising: an image forming unit that forms an image based on a document image read by the image reading apparatus.

Images