JP5618750B2 - Image reading apparatus and image forming apparatus having the same - Google Patents

Description

  The present invention relates to an image reading apparatus that reads a document. The present invention also relates to an image forming apparatus provided with the image reading apparatus.

  2. Description of the Related Art Conventionally, there is an image reading apparatus that reads a document and outputs image data (for example, a scanner). In general, an image reading apparatus includes a lamp that irradiates light on a document, an image sensor that receives photoelectrically reflected light from the document, and performs photoelectric conversion. The image reading apparatus may be mounted on an image forming apparatus such as a copying machine, a multifunction machine, or a FAX apparatus for copying and transmission. In recent years, a lamp in which a plurality of LEDs are arranged in place of a fluorescent tube or a halogen lamp is used as a lamp of an image reading device because of low power consumption and a short time until the light emission is stabilized after lighting. May be.

  An LED included in the lamp may fail (no longer turn on) due to overcurrent, disconnection, contact failure, soldering error, and the like. However, as compared with a line light source such as a fluorescent tube, even if a failure occurs in a lamp, not all LEDs are turned on. For example, a lamp may have a plurality of blocks in which a plurality of LEDs are connected in series. In such a lamp, even if an LED fails in a single unit or in blocks, other LEDs are lit and it is difficult to determine whether a failure has occurred. An example of an image reading apparatus that detects a failure of a lamp using a plurality of LEDs is described in Patent Document 1.

Specifically, Patent Document 1 discloses an image reading apparatus that includes an LED array in which a plurality of LED blocks each having a plurality of LEDs connected in series are arranged in series, and a drive control unit that performs constant voltage drive control of the LED array. The current detection means for detecting the current flowing through the LED array by controlling the drive by the drive control means, and comparing the current value detected by the current detection means with a predetermined threshold value, whether or not the LED is faulty based on the comparison result An image reading apparatus having a determination means for determining With this configuration, an image reading apparatus that automatically detects a failure of an LED array is provided (see Patent Document 1: Claim 1, paragraph [0004], etc.).
JP 2004-040669 A

  The invention described in Patent Document 1 performs failure detection for each LED block using current detection means (see Patent Document 1: Paragraph [0025] and the like). Thereby, the failed LED block can be detected. However, in the invention described in Patent Document 1, if there are a large number of blocks, there is a problem that detection takes time.

  When the light source (lamp) is a plurality of LEDs arranged in an array (array form), it is preferable to specify the location and number of failed LEDs (no longer lit) in order to determine whether or not reading is possible. For example, if there is only one failed LED, the document size can be read if the failed LED is not used. However, the invention described in Patent Document 1 cannot identify a faulty LED.

  In the invention described in Patent Document 1, it is determined whether or not a failure has occurred based on the current value flowing through the block. Specifically, in the invention described in Patent Document 1, an analog switch 301 for switching the LED block to be measured (what kind of switch is unknown), an A / D converter 303, a control program, and a CPU 304 are used. The flowing current is measured (see Patent Document 1: Paragraphs [0017] and [0018]). As described above, the invention described in Patent Document 1 has a problem that a circuit for measuring current (measuring instrument) flowing through the LED and wiring are necessary. The circuit for measuring current (measuring instrument) and the wiring associated therewith are only for measuring the current flowing through the LED, and there is a problem that the cost required for manufacturing the image reading apparatus increases.

  In view of the above-described problems of the conventional technology, an object of the present invention is to detect a failed LED without incorporating a measuring device for the current flowing through the LED into an image reading apparatus.

In order to achieve the above object, the image reading apparatus according to claim 1 includes a plurality of blocks each including a plurality of LEDs, and the LEDs in the other blocks are arranged between the LEDs in the block. Included in the lamp are an LED in which LEDs are arranged, an image sensor that is irradiated with light that is irradiated from the lamp, reflected by a reading object, and guided by an optical member, and that reads at least the reading object in units of lines. A failure detection unit that detects a failure of the LED, and a display unit that displays a failure detection result and a status display, and when performing failure detection that detects a failure of the LED included in the lamp, the lamps are arranged side by side The LED is turned on / off in units of blocks so that at least one LED is turned on at a time, and the failure detection unit outputs to the output of the image sensor. In the image data that follows, based on whether or not the light level of the pixel corresponding to the lit LED is greater than or equal to a predetermined threshold value, a failure of the LED is detected, and the display unit fails in the LED included in the lamp. when there, when reading the document placed in accordance with the reference point on the contact glass placement reading, it was decided to display the size of the readable document.

  According to this configuration, the failure detection unit detects a failure of the LED based on whether or not the light amount level of the pixel corresponding to the lit LED is greater than or equal to a predetermined threshold in the image data. Thereby, since the failure detection unit detects whether the LED is turned on or not based on the image data, a measuring instrument (circuit) for measuring the current flowing through the LED is not necessary. Therefore, it is possible to reduce the manufacturing cost of the image reading apparatus and simplify the design of the image reading apparatus.

  Further, when a failure is detected, if an LED adjacent to a failed LED (a non-lighting LED) is lit, the failure may not be detected due to the influence of irradiation light of the adjacent LED. However, according to this configuration, the LED in the other block is arranged between the LEDs in the block, and at least one of the arranged LEDs is turned on, and the adjacent LED is not turned on. Can be. Therefore, the position of the failed LED can be accurately identified.

  According to the present invention, it is possible to provide an image reading apparatus and an image forming apparatus in which it is not necessary to incorporate a current measuring device flowing through the LED into the image reading apparatus in order to detect a failure of the LED. It is also possible to provide an image reading apparatus and an image forming apparatus that can detect a failed LED reliably, accurately, and in a short time.

1 is a schematic front cross-sectional view illustrating a schematic configuration of a multifunction machine according to a first embodiment. 1 is a schematic cross-sectional view illustrating an example of an image reading apparatus according to a first embodiment. It is a top view which shows an example when the image reading part which concerns on 1st Embodiment is seen from upper direction. 1 is a block diagram illustrating an example of a configuration of a multifunction machine according to a first embodiment. FIG. 3 is a block diagram illustrating an example of a configuration of an image reading unit and a document conveying unit according to the first embodiment. It is explanatory drawing which shows an example of the lamp | ramp which concerns on 1st Embodiment. It is explanatory drawing which shows an example of the block division of the lamp | ramp which concerns on 1st Embodiment. It is explanatory drawing for demonstrating the failure detection process which concerns on 1st Embodiment. It is explanatory drawing which shows an example of the detection result display screen which concerns on 1st Embodiment. It is explanatory drawing which shows an example of the detection result display screen which concerns on 1st Embodiment. 6 is a flowchart illustrating an example of a flow of failure detection control in the image reading apparatus according to the first embodiment. It is explanatory drawing which shows an example of the block division of the lamp | ramp which concerns on 2nd Embodiment.

  A first embodiment of the present invention will be described below with reference to FIGS. However, each element such as configuration and arrangement described in this embodiment does not limit the scope of the invention and is merely an illustrative example.

(Outline of image forming apparatus)
First, an outline of an electrophotographic multifunction machine 200 (corresponding to an image forming apparatus) including the image reading apparatus 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a front-view schematic cross-sectional view showing a schematic configuration of a multifunction machine 200 according to the first embodiment of the present invention.

  As shown in FIG. 1, the multifunction peripheral 200 according to the present embodiment includes an image reading apparatus 100 on the upper side. The image reading apparatus 100 includes an image reading unit 1, a document conveying unit 2, and an operation panel 3. Details of the image reading unit 1 and the document conveying unit 2 will be described later.

  As indicated by a broken line in FIG. 1, an operation panel 3 is provided on the front side of the image reading unit 1. The operation panel 3 includes a liquid crystal display unit 30 (corresponding to a display unit) that displays keys for setting the multifunction device 200 and receives user input. Further, the liquid crystal display unit 30 can display the failure detection result of the LED 7 and the state of the multifunction device 200 and the image reading apparatus 100 such as an error. In addition, a numeric keypad 31 for inputting numbers such as the number of copies, a start key 32 for instructing copy execution, and the like are arranged on the operation panel 3.

  As shown in FIG. 1, the MFP 200 of the present embodiment includes a sheet feeding unit 4A, a conveyance path 4B, an image forming unit 5A, an intermediate transfer unit 5B, a fixing unit 5C, and the like inside the main body.

  Each of the plurality of paper supply units 4A in the main body has each size (for example, A type, B type paper such as A4, B4, etc.) and various types of paper (for example, copy paper, recycled paper, cardboard, OHP sheet, etc.). Accommodates multiple sheets. Each paper feed unit 4A includes a paper feed roller 41 that is driven to rotate, and feeds paper one by one to the transport path 4B during printing.

  The transport path 4B is a path for transporting paper in the apparatus. Then, on the conveyance path 4B, a guide for guiding the sheet, a pair of conveyance rollers 42 that are rotationally driven during conveyance of the sheet (a total of three from 42A, 42B, and 42C from the top in FIG. 1) and the conveyance path 4B are conveyed. There are provided a registration roller pair 43 and the like for waiting the sheet in front of the image forming unit 5A and feeding the sheet in accordance with the transfer timing of the formed toner image. In addition, a pair of discharge rollers 45 for discharging the sheet after completion of fixing to the discharge tray 44 is also provided.

  The image forming unit 5A includes a plurality of image forming units 50 (50Bk for black, 50Y for yellow, 50C for cyan, 50M for magenta) and an exposure device 51. The exposure device 51 outputs laser light while turning it on and off based on the image data read by the image reading unit 1, and scans and exposes each photosensitive drum. The image forming unit 50 includes a photosensitive drum that is rotatably supported, and a charging device, a developing device, a cleaning device, and the like disposed around the photosensitive drum. Then, a toner image is formed on the peripheral surface of the photosensitive drum by each image forming unit 50 and the exposure device 51.

  The intermediate transfer unit 5B receives the primary transfer of the toner image from each image forming unit 50 and performs the secondary transfer on the sheet. The intermediate transfer unit 5B includes primary transfer rollers 52Bk to 52M, an intermediate transfer belt 53, a driving roller 54, a plurality of driven rollers 55, a secondary transfer roller 56, a belt cleaning device 57, and the like. Each primary transfer roller 52 </ b> Bk to 52 </ b> M sandwiches a corresponding photosensitive drum and an endless intermediate transfer belt 53. A transfer voltage is applied to each of the primary transfer rollers 52 </ b> Bk to 52 </ b> M, and the toner image is transferred to the intermediate transfer belt 53.

  The intermediate transfer belt 53 is stretched around a driving roller 54 and the like, and rotates around the driving roller 54 connected to a driving mechanism (not shown) such as a motor. The drive roller 54 sandwiches the intermediate transfer belt 53 with the secondary transfer roller 56. The toner images (black, yellow, cyan, and magenta colors) formed by each image forming unit 50 are sequentially transferred to the intermediate transfer belt 53 in a superimposed manner without deviation, and then applied with a predetermined voltage. The image is transferred onto the sheet by the secondary transfer roller 56.

  The fixing unit 5C fixes the toner image transferred to the paper. The fixing unit 5C mainly includes a heating roller 58 containing a heating element and a pressure roller 59 in pressure contact therewith. When the sheet passes through the nip between the heating roller 58 and the pressure roller 59, the toner is melted and heated, and the toner image is fixed on the sheet. The sheet discharged from the fixing unit 5C is sent to the discharge tray 44.

(Configuration of Image Reading Apparatus 100)
Next, an example of the image reading apparatus 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing an example of the image reading apparatus 100 according to the first embodiment of the present invention. In FIG. 2, the operation panel 3 is not shown.

  First, the document conveying unit 2 is provided above the image reading unit 1, and the front side opens and closes with respect to the image reading unit 1 in the vertical direction. Then, the document transport unit 2 automatically and continuously transports a document (read target) to be read one by one toward the transport reading contact glass 11 (reading position). The document transport unit 2 includes, in order from the upstream side in the document transport direction, a document tray 21, a document supply roller 22, a document transport path 23, a plurality of document transport roller pairs 24, a document discharge roller pair 25, a document discharge tray 26, and the like. Further, the document conveying unit 2 is attached to the image reading unit 1 so as to be able to be opened and closed in the vertical direction with the back side of the paper surface of FIG. Function.

  A plurality of documents are placed on the document tray 21. Then, the document supply roller 22 contacts the uppermost document among the documents placed on the document tray 21. For example, when an input for reading a document, such as pressing of the start key 32, is input to the multi-function peripheral 200, the document supply roller 22 sends the document one by one to the document transport path 23.

  The fed document is guided to a plurality of document transport roller pairs 24 and guides, and passes through the upper surface of the transport reading contact glass 11 provided on the upper surface of the image reading unit 1. During this passage, the image reading unit 1 performs reading. Then, the document that has been read is discharged from the document discharge roller pair 25 to the document discharge tray 26 (the document transport path is shown by a two-dot chain line). Each of the rotating bodies (the document supply roller 22, the document transport roller pair 24, and the document discharge roller pair 25) rotates with the document transport motor 27 (see FIG. 5) as a drive source.

  Next, the image reading unit 1 in the present embodiment will be described. The image reading unit 1 irradiates light onto the upper surface of the transport reading contact glass 11 or the placement reading contact glass 12 and generates image data by the image sensor 15 based on the reflected light.

  As shown in FIGS. 1 and 2, the image reading unit 1 has a box-shaped housing. Then, on the left side of the upper surface of the image reading unit 1, a transparent plate-shaped conveyance reading contact glass 11 is arranged extending in a direction perpendicular to the paper surface of FIG. 2. Then, on the right side of the upper surface of the image reading unit 1, a transparent plate-like placement reading contact glass 12 is arranged extending in a direction perpendicular to the paper surface. The placement reading contact glass 12 is provided on the upper surface of the image reading unit 1. When reading a document such as a book one by one, the document is placed on the placement and reading contact glass 12 with the document transport unit 2 lifted and the reading surface facing downward.

  A white reference plate 11W (for example, a pure white resin plate) for obtaining a white reference in shading correction is provided below the document guide member 11G between the conveyance reading contact glass 11 and the placement reading contact glass 12. Is provided. The image reading unit 1 reads the white reference plate 11W and determines the white reference at each pixel of the line in the main scanning direction.

  As shown in FIG. 2, an optical system member such as a first moving frame 131, a second moving frame 132, a wire 133, a take-up drum 134, and a lens 14 in the housing of the image reading unit 1, and a document A lamp 6 for irradiating light and light irradiated on the original are incident, and an image sensor 15 for reading the original for each line and generating image data is disposed. The image sensor 15 is constituted by, for example, a CCD (Charge Coupled Device) in which photoelectric conversion elements are arranged in a line shape, and reads a document line by line in the main scanning direction based on the reflected light of the document.

  The light emitted from the lamp 6 strikes the original on the conveyance reading contact glass 11, and the reflected light is reflected by the optical system members such as the first mirror 161, the second mirror 162, and the third mirror 163, and guided to the lens 14. . The lens 14 collects the reflected light and enters the image sensor 15. The image sensor 15 is a line sensor in which a plurality of light receiving elements are arranged in three lines of R, G, and B, for example. The image sensor 15 converts the reflected light into an analog electrical signal corresponding to the image density. The original is read line by line in the main scanning direction (perpendicular to the original conveying direction), and the reading in line units is continuously repeated in the sub-scanning direction (original conveying direction). Read.

  The first moving frame 131 supports the lamp 6 that emits light upward and the first mirror 161 downward. The lamp 6 and each mirror have a shape extending in the direction perpendicular to the paper surface of FIG. The second moving frame 132 supports the second mirror 162 upward and the third mirror 163 downward. Further, the first moving frame 131 is disposed above the second moving frame 132. A plurality of wires 133 are attached to the first moving frame 131 and the second moving frame 132 (only one is shown in FIG. 2 for convenience). The other end of the wire 133 is connected to the take-up drum 134. The take-up drum 134 rotates forward and backward using the take-up motor 13M (see FIG. 5) as a drive source, and the first moving frame 131 and the second moving frame 132 are Move freely in the horizontal direction.

  Here, an example of a specific document reading operation will be described. First, in the case of reading a document transported by the document transport unit 2, after the winding motor 13M is driven, the first moving frame 131 and the second moving frame 132 are positioned below the transport reading contact glass 11 (reading position). ). The lamp 6 irradiates light on the passing document. The details of the lamp 6 will be described later.

  On the other hand, when reading a document placed on the placement reading contact glass 12, the first moving frame 131 and the second moving frame 132 are moved from the home position to the right in FIG. The entire original is read, and the original image is converted into an electrical signal.

(Scanning the document)
Next, based on FIG. 3, an outline of document reading by the image reading apparatus 100 according to the first embodiment of the present invention will be described. FIG. 3 is a plan view showing an example when the image reading unit 1 according to the first embodiment of the present invention is viewed from above.

  When a book or the like is used as an original, the user places the original on the placement reading contact glass 12 with the reading surface facing downward. Then, the document is placed according to the reference point P of the document. In the multifunction device 200 of the present embodiment, the upper left corner of the placement reading contact glass 12 is the reference point P when the multifunction device 200 is viewed from above. The user places the original by aligning the upper left corner of the original with the reference point P. Further, for example, the document is transported by the document transport unit 2 so that the upper side of the document placed on the document tray 21 (the side on the back side parallel to the document transport direction) coincides with the reference point P.

  In the multifunction device 200 of the present embodiment, for example, the maximum size that can be read is a standard size and is an A3 size. Therefore, the width in the main scanning direction that can be read by the image reading unit 1 is approximately 30 cm. With this width in the main scanning direction, the lamp 6 irradiates the original with light.

(Hardware configuration of MFP 200)
Next, an example of the hardware configuration of the multifunction machine 200 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing an example of the configuration of the multifunction machine 200 according to the first embodiment of the present invention.

  First, the main body control unit 8 is provided in the multifunction device 200. The main body control unit 8 controls each unit of the multifunction device 200. The main body control unit 8 of the multifunction device 200 is provided with a CPU 81 as a central processing unit. In addition, a storage unit 82 composed of nonvolatile and volatile memories such as a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), and a flash ROM is included in the main body control unit 8 (main unit control unit). 8 may be provided).

  The storage unit 82 stores programs, data, and the like for controlling the multifunction device 200. The main body control unit 8 can communicate with each unit (the operation panel 3, the sheet feeding unit 4A, the conveyance path 4B, the image forming unit 5A, the intermediate transfer unit 5B, and the fixing unit 5C) using the program and data stored in the storage unit 82. Connected to and controlled to perform printing or the like. The main body control unit 8 is a main control unit that performs overall control, communication control, and image processing, an engine control unit that controls printing by performing ON / OFF of a motor that rotates an image forming and various rotating bodies, and the like. A plurality of types may be provided for each function. In this description, a configuration in which these control units are combined is shown and described.

  The main body control unit 8 is provided with a second image processing unit 83 that performs image processing based on image data processed by a first image processing unit 9 (details will be described later) provided in the image reading apparatus 100. For example, the second image processing unit 83 includes an ASIC, a memory, and the like, and can perform various types of image processing such as density conversion processing, enlargement / reduction processing, rotation processing, image data compression / decompression processing, and the like. Note that the second image processing unit 83 can perform other image processing (for example, frame erasing processing) and the like, but will not be described as being capable of performing known image processing.

  Also, settings and copy execution instructions on the operation panel 3 are transmitted to the main body control unit 8. Therefore, the operation panel 3 functions as a part for performing setting input and display of the image reading apparatus 100 as well as a part for performing setting input and display of the multifunction device 200. The main body control unit 8 is also connected to the image reading apparatus 100 and gives an operation instruction to the image reading apparatus 100 at the time of executing a copy. For this reason, the main body control unit 8 sometimes functions as a control unit of the image reading apparatus 100. Then, the main body control unit 8 receives the image data of the document at the time of copying, and performs printing (copying) based on the image data.

  The communication unit 84 is an interface for communicating with an external computer 300 (for example, a personal computer) or the FAX apparatus 400 through a network, a line, a cable, or the like. Therefore, the communication unit 84 includes various connectors, communication circuits, elements, controllers, and the like. The main body control unit 8 can receive printing data from the external computer 300 or the FAX apparatus 400 through communication via the communication unit 84, and can transmit image data to the external computer 300 or the FAX apparatus 400 (scanner function, FAX function).

(Hardware configuration of image reading unit 1 and document conveying unit 2)
Next, an example of the hardware configuration of the image reading unit 1 and the document conveying unit 2 according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a block diagram showing an example of the configuration of the image reading unit 1 and the document conveying unit 2 according to the first embodiment of the present invention. FIG. 6 is an explanatory diagram showing an example of the lamp 6 according to the first embodiment of the present invention. FIG. 7 is an explanatory diagram showing an example of block division of the lamp 6 according to the first embodiment of the present invention.

  As described above, the image reading apparatus 100 according to the present embodiment includes the document conveying unit 2 and the image reading unit 1. The document transport unit 2 is provided with a document transport control unit 20 that controls the operation of the document transport unit 2. On the other hand, the image reading unit 1 is provided with a reading control unit 10 (corresponding to a failure detection unit) that controls the operation of the image reading unit 1.

  First, the document conveyance control unit 20 will be described. The document conveyance control unit 20 is connected to the main body control unit 8 and the reading control unit 10 described above, and controls the operation of the document conveyance unit 2 in response to instructions and signals from the main body control unit 8 and the reading control unit 10. The document conveyance control unit 20 is a substrate including, for example, a CPU, a ROM, and a RAM as a storage device that stores a control program and data. The document conveyance control unit 20 communicates with the main body control unit 8 and the like, and receives an instruction from the main body control unit 8 and performs actual operation control of the document conveyance unit 2. For example, when there is a document reading instruction from the main body control unit 8 for copying or the like, the document conveying motor 27 is driven to rotate the document supply roller 22 or the document conveying roller pair 24.

  Next, the image reading unit 1 will be described. The image reading unit 1 is provided with a reading control unit 10 as a part that actually controls the operation of the image reading unit 1. The reading control unit 10 is also a board including a CPU as a central processing unit, a program necessary for controlling the image reading apparatus 100, a ROM, a RAM, and the like as storage devices for storing data.

  The reading control unit 10 is communicably connected to the main body control unit 8 and the document conveyance control unit 20 described above. The reading control unit 10 receives instructions and signals from the main body control unit 8 and controls the operation of the image reading unit 1. For example, when the start key 32 of the operation panel 3 is pressed, the reading control unit 10 receives an instruction from the main body control unit 8, and the reading control unit 10 is obtained by operation control or reading of the image reading unit 1 or the image reading apparatus 100. Transmission control of the image data of the document to the main body control unit 8 is performed. Further, the reading control unit 10 controls the rotation of the winding motor 13M, rotates the winding drum 134, and moves each moving frame.

  The reading control unit 10 is connected to the lamp 6, the image sensor 15, the A / D conversion unit 91, the first image processing unit 9, and the like, and instructs to read the document, in other words, to be driven. Give instructions.

  The lamp 6 includes a white LED 7. The white LED 7 may be a combination of LEDs 7 of red, green, and blue, or a blue LED 7 provided with a yellow filter. The LED 7 included in the lamp 6 is not necessarily limited to one that emits white light, and may emit light of another color (for example, any color of red, green, and blue).

  Here, an example of the lamp 6 will be described with reference to FIG. As shown in FIG. 6, the lamp 6 of this embodiment is a type of lamp 6 in which a plurality of LEDs 7 are arranged (arranged) in a line. For example, if the width of one LED 7 is 1 cm, about 30 LEDs 7 are arranged in accordance with the reading width in the main scanning direction.

  Next, the block 77 of the LED 7 in the lamp 6 will be described with reference to FIG. In FIG. 7, a square with a number indicates the LED 7. The numbers in the squares indicate the numbers of the blocks 77 to which the respective LEDs 7 belong.

  The block 77 in the lamp 6 of the present embodiment is obtained by connecting a plurality of LEDs 7 in parallel. In the present embodiment, an example in which a parallel circuit of three LEDs 7 is handled as one block 77 will be described. Note that the number of LEDs 7 in one block 77 is not limited to three, and may be two or four or more. Further, the LEDs 7 in one block 77 may be connected in series (a series circuit may be used). In the present embodiment, a plurality of blocks 77 are arranged. As a result, a plurality of LEDs 7 are arranged to form one lamp 6. In FIG. 7, the first to eighth blocks are shown as an example, and even-numbered blocks are shaded.

  In the lamp 6 of the present embodiment, the LEDs 7 of different blocks 77 are arranged between the LEDs 7 of one block 77. For example, in FIG. 7, the LEDs 7 of the second block are arranged between the LEDs 7 of the first block. This takes into account the combination of LEDs 7 to be lit when a failure is detected. Strictly speaking, one even-numbered LED 7 is arranged between each odd-numbered LED 7. One odd-numbered LED 7 is arranged between each even-numbered LED 7. In terms of block units, an even block LED is sandwiched between one odd block and the next odd block, and an odd block LED is sandwiched between one even block and the next even block. It is.

  As shown in FIG. 5, the lamp 6 is provided with a lighting circuit 60 as a switch for turning on / off each color. The lighting circuit 60 lights all the blocks 77 (all LEDs 7) in normal reading. On the other hand, the lighting circuit 60 turns on the LEDs 7 in the odd-numbered blocks and then turns on the LEDs 7 in the even-numbered blocks when the failure of the LED 7 is detected. Note that after the even-numbered block LEDs 7 are turned on, the odd-numbered block LEDs 7 may be turned on.

  In this way, since one LED 7 of the other block 77 is arranged between the LEDs 7 of the same block 77, only the LED 7 of the odd or even block can be turned on, so that the LED 7 can be turned on by one. it can. When the failure of the LED 7 is detected, the lamp 6 and the adjacent LEDs 7 are not lit at the same time.

  The image sensor 15 receives the light irradiated on the document, and outputs three types of analog electrical signals of R, G, and B for each pixel. The magnitude of the electric signal varies depending on the amount of received light (light quantity level). The A / D converter 91 receives the analog electric signal of each pixel obtained by the image sensor 15 and performs quantization to convert it into a digital signal. For example, the A / D conversion unit 91 performs quantization on 8 bits (24 bits in total) for R, G, and B, respectively.

  The first image processing unit 9 receives the image data output from the A / D conversion unit 91 and performs image processing. In the present embodiment, the first image processing unit 9 is used as the image reading unit 1 and the second image processing unit. An example in which 83 is provided in the main body control unit 8 will be described. However, for example, only one image processing unit is provided on the main body side or in the image reading unit 1, and the processing of the first image processing unit 9 and the second image processing unit in the present description are included in only one image processing unit. You may make it perform the process of 83. In other words, only one image processing unit may be provided.

  In the first image processing unit 9, a work memory 92, a lighting control unit 93, a synchronization signal generation unit 94, a synthesis processing unit 95, a correction processing unit 96, and the like are provided. The work memory 92 is a work area for processing image data, and the image data from the A / D converter 91 is stored in the work memory 92. The synchronization signal generator 94 generates a synchronization signal for synchronizing with reading of the document. For example, the synchronization signal generation unit 94 generates a horizontal synchronization signal HSYNC for synchronization by reading one line.

  The horizontal synchronization signal HSYNC is given to, for example, the lighting control unit 93, the image sensor 15, and the A / D conversion unit 91. For example, when detecting a failure of the LED 7 or reading a document, the image sensor 15 starts outputting an electrical signal from the pixel at the head of one line in accordance with the horizontal synchronization signal HSYNC. For example, the A / D converter 91 digitizes the electrical signal in accordance with the horizontal synchronization signal HSYNC, and outputs the image data to the first image processor 9.

  For example, the lighting control unit 93 is a PWM circuit, and gives a signal indicating a block 77 to be lit (lighting block instruction signal G1) to the lighting circuit 60 based on an instruction from the reading control unit 10 (in FIG. The signal lines are shown.) The lighting circuit 60 functions as a switch for lighting the block 77 (LED 7) whose signal from the lighting control unit 93 is High.

  The composition processing unit 95 generates monochrome image data from R, G, and B color image data. In other words, the composition processing unit 95 generates image data of luminance signals from the image data of R, G, and B colors. That is, each pixel value of the image data indicates the level of the amount of reflected light. For example, the composition processing unit 95 performs processing when detecting a failure of the LED 7 of the lamp 6 or copying in black and white.

  The reading control unit 10 detects a failure of the LED 7 included in the lamp 6 and specifies the position of the failed LED 7 or the block 77. The reading control unit 10 may perform failure detection processing based on image data for one line of each color of R, G, and B. However, in the present embodiment, an example will be described in which the reading control unit 10 receives image data for one line processed by the synthesis processing unit 95 and performs failure detection processing.

  The correction processing unit 96 corrects distortion derived from the characteristics of the LED 7 lamp 66 and the image sensor 15 such as gamma correction and shading correction on the image data. The image data processed by the first image processing unit 9 is stored in the image memory 97 and then transferred to the main body control unit 8. Further, after the second image processing unit 83 performs image processing, for example, image data is given to the exposure device 51. Note that the reading control unit 10 may receive the image data for one line subjected to the image processing by the synthesis processing unit 95 and the correction processing unit 96 and perform the failure detection processing.

(Fault detection processing)
Next, failure detection processing according to the first embodiment of the present invention will be described based on FIG. FIG. 8 is an explanatory diagram for explaining the failure detection processing according to the first embodiment of the present invention. The squares between the two graphs in FIG. 8 each indicate an LED 7, and a block 77 belonging to each LED 7 is entered. The LED 7 in the lit state is shown with a black character white background, the LED 7 in the off state is shown with a white character black background, and the failed LED 7 is shown with shading.

  When the failure of the LED 7 is detected, the reading control unit 10 of the present embodiment turns on the LED 7 of the lamp 6 in a single step. Then, the reading control unit 10 specifies the position of the LED 7 and the block 77 that are not lit based on the read image data. For example, when performing failure detection, the reading control unit 10 reads the white reference plate 11W by moving the lamp 6, each moving frame, and the like to a position where the white reference plate 11W is read, for example.

  First, the upper graph of FIG. 8 shows the distribution of the light amount level in the image data of one line in the main scanning direction when the reading control unit 10 turns on the even-numbered block 6 of the lamp 6 that has no failure and reads the white reference plate 11W. Is shown.

  The graph in the lower part of FIG. 8 shows one line in the main scanning direction when the reading control unit 10 reads the white reference plate 11W by turning on the LEDs 7 of the even-numbered blocks in the lighting control unit 93 for failure detection. The distribution of the light quantity level in the image data is shown. The light amount level corresponds to the pixel value of each pixel in the image data. For example, the A / D conversion unit 91 outputs a larger pixel value as the amount of light received by each pixel of the image sensor 15 is larger.

  For example, as shown in the lower graph of FIG. 8, the light intensity level of the pixel at the position corresponding to the LED 7 that is faulty and does not light is lower than the threshold value. Therefore, the reading control unit 10 detects that the LED 7 that irradiates the portion below the threshold is broken. For example, the lower graph in FIG. 8 shows an example in which one LED 7 is not turned on among the LEDs 7 included in the second block.

  Further, in the block 77 that does not fail, all the pixels at positions corresponding to the LEDs 7 included in the block 77 have a light amount level below the threshold value. Therefore, the reading control unit 10 detects that the block 77 that irradiates the portion below the threshold is broken. For example, the lower graph in FIG. 8 shows an example in which the sixth block fails and all the LEDs 7 included in the sixth block are not turned on.

  If there is no failure in the LED 7, the light quantity level of the pixel irradiated by the lit LED 7 is large and the pixel value shows a bright value. On the other hand, if there is a failure in the LED 7, the light amount level of the pixel irradiated by the lit LED 7 is small and the pixel value indicates a dark value. Therefore, a threshold value is provided to confirm whether the LED 7 that has been turned on is turned on. The reading control unit 10 determines whether the LED 7 is out of order based on whether the light amount level (pixel value) is greater than or less than a threshold value. The threshold value is stored in the memory 17 of the image reading unit 1, for example.

  Here, in the specification, it is determined in advance from the number of pixels to the number of pixels in the image data of one line in the main scanning direction that corresponds to the portion irradiated by each LED 7 (the range of each LED 7). In a relationship. And the reading control part 10 does not need to compare a pixel value and a threshold value about all the pixels corresponding to the irradiation part of LED7 which made it light. For example, a pixel (one or a plurality) of positions on a line in the main scanning direction corresponding to the central axis (position that can be brightest) in the light irradiation of each LED 7 is set as a representative point in one LED 7. The representative point may be arbitrarily determined within the range of each LED 7. Then, the reading control unit 10 may check whether the LED 7 is out of order by comparing the pixel value (light amount level) of the representative point pixel corresponding to each LED 7 with a threshold value.

  For example, the memory 17 in the image reading unit 1 stores the position of the pixel to be compared with the threshold according to the lighting pattern (the combination of the LEDs 7 that light up the odd blocks and the even blocks). In other words, the memory 17 stores information (comparison pixel position information) corresponding to each LED 7 and indicating the position of the pixel to be compared with the threshold value. Then, the reading control unit 10 uses the threshold value stored in the memory 17 or the pixel at the position defined in the comparison pixel position information to determine whether each LED 7 is out of order.

(Display accompanying failure detection)
Next, an example of display accompanying failure detection in the image reading apparatus 100 according to the first embodiment of the present invention will be described with reference to FIGS. 9 and 10. 9 and 10 are explanatory diagrams illustrating examples of the detection result display screens S1 and S2 according to the first embodiment of the present invention.

  If a failure occurs in any of the LEDs 7 included in the lamp 6, the level of the amount of light applied to the document decreases at the failed portion, resulting in dark reading. Accordingly, the reproducibility of the original document is lowered.

  However, depending on the location of the failed LED 7, even if there is a problem in reading a large-size document, there may be no problem with a small-size document. In the image reading unit 1 of this embodiment, the reference point P and the upper left corner of the document are aligned and the document is read. Therefore, the lamp 6 emits light within the range of the maximum reading width along the main scanning direction from the reference point P.

  If the position of the failed LED 7 is, for example, a position farther from the reference point P than the length of the short side of the A4 paper (front side), the main scanning direction and the short side of the A4 paper are read in parallel. Then, reading can be performed without being affected by the failed LED 7. Therefore, based on the position of the failed LED 7 specified by the reading control unit 10, the detection result display screens S1 and S2 are displayed on the operation panel 3.

  The liquid crystal display unit 30 of the operation panel 3 displays a detection result display screen S1 as shown in FIG. 9 when there is a document of a size that can be read without being affected by the failure of the LED 7 even if the LED 7 has a failure. . As a result, the user can know the size of the original that can be read without problems for copying and the like. Even if the LED 7 included in the lamp 6 breaks down, the multifunction device 200 does not immediately become unavailable. Further, since the liquid crystal display unit 30 of the operation panel 3 has a failure in the LED 7, the size of the document affected by the failure of the LED 7 is also displayed on the detection result display screen S1.

  On the other hand, when a failure occurs in the LED 7 at a position close to the reference point P (for example, an LED 7 whose position from the reference point P is closer than the length of the side of the smallest readable paper), there is no influence by the failure of the LED 7. There is no document size that can be scanned. In such a case, the liquid crystal display unit 30 of the operation panel 3 displays a non-readable detection result display screen S2 as shown in FIG.

  For example, the reading control unit 10 of the image reading unit 1 obtains the size of the original that does not affect the reading and the size of the affected original based on the position of the LED 7 detected as a failure. For example, table data that defines the document size that has an effect on reading is stored in the memory 17 of the image reading unit 1 for the position of the failed LED 7 or block 77. Then, the reading control unit 10 compares the table data and the position of the failure LED 7 to obtain the size of the document that does not affect the reading and the size of the document that has an effect.

  The reading control unit 10 sends the obtained result to the main body control unit 8. Then, the main body control unit 8 transfers the obtained result to the operation panel 3. Alternatively, the reading control unit 10 transmits the obtained result directly to the operation panel 3. In response to the obtained result, the operation panel 3 displays the failure detection result on the liquid crystal display unit 30. The table data is stored in the storage unit 82, the main body control unit 8 receives the position information of the failed LED 7 from the reading control unit 10, and the main body control unit 8 determines the size of the original that does not affect the reading and the influence. You may ask for the size of a document.

(Flow of failure detection control)
Next, the flow of failure detection control in the image reading apparatus 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 11 is a flowchart illustrating an example of a flow of failure detection control in the image reading apparatus 100 according to the first embodiment of the present invention.

  The start in FIG. 11 is a point in time when failure detection is started. At this time, the main body control unit 8 gives an instruction to the reading control unit 10 to detect the failure of the LED 7 of the lamp 6. The failure detection can be performed at an arbitrary time. For example, failure detection can be performed when the main power supply of the multifunction device 200 is turned on, when returning from the power saving mode, or when the start key 32 is pressed to start copying or the like.

  When the failure detection is started, the lighting control unit 93 lights the LEDs 7 of the odd-numbered blocks 77 among the blocks 77 included in the lamp 6 (step # 1). At this time, the LED 7 is turned on by one. That is, the lamp 6 is arranged such that one LED 7 of another block 77 is arranged between the LED 7 and the LED 7 in the block 77, and when the failure is detected, the arranged LED 7 is skipped by one. The LED 7 is turned on and off in units of blocks 77 so that it is lit. Then, the reading control unit 10 operates the winding motor and the image sensor 15 to read the white plate (step # 2). Then, image data is obtained as a reading result (step # 3).

  Then, the reading control unit 10 reads data (comparison pixel position information) indicating the position of the pixel to be compared with the threshold value in the image data corresponding to the position of the LED 7 of the odd block from the threshold value, the memory 17 or the like (step) # 4). Then, based on the read threshold value and the like, the reading control unit 10 compares the pixel value of each pixel (the light amount level of each LED 7) with the threshold value in the image data (step # 5).

  That is, the image reading apparatus 100 according to the present invention includes a plurality of blocks 77 including a plurality of LEDs 7, and the LEDs 7 of the other blocks 77 are arranged between the LEDs 7 in the block 77 and the LEDs 7. The reflected light of the reading object is incident at least by the read lamp 6, the optical system member (first moving frame 131 and the like) that guides the light irradiated from the lamp 6 and reflected by the reading object, and the optical system member. The image sensor 15 that reads the target in units of lines, and a failure detection unit (reading control unit 10) that detects a failure of the LED 7 included in the lamp 6, and detects a failure of the LED 7 included in the lamp 6 When performing, the lamp 6 switches on / off of the LEDs 7 in units of block 77 so that at least one of the arranged LEDs 7 is lit, and the fault detection is performed. The unit (reading control unit 10) detects a failure of the LED 7 based on whether or not the light amount level of the pixel corresponding to the LED 7 that is turned on is equal to or higher than a predetermined threshold in the image data based on the output of the image sensor 15. To do.

  Then, the reading control unit 10 confirms whether there is an LED 7 that is not turned on, in other words, whether there is a failure in the LED 7, depending on whether there is an LED 7 (pixel) that is below the threshold (step # 6). . If there is a failure (Yes in step # 6), the reading control unit 10 checks whether or not the failure is in units of block 77 (step # 7). That is, the failure detection unit (reading control unit 10) detects whether or not a failure occurs in units of block 77 based on the position of the lit LED 7, and / or whether or not a failure occurs in units of LED 7. Detect whether or not.

  If the failure is in units of blocks 77 (Yes in step # 7), data indicating the block 77 identified as a failure is stored in the memory 17 (may be the storage unit 82 on the main body side) (step # 8). ). On the other hand, if the failure is not the block 77 unit but the LED 7 alone (No in step # 7), the data indicating the position of the LED 7 identified as the failure is stored in the memory 17 (may be the storage unit 82 on the main body side). Is stored (step # 9). Data indicating these failure positions is used for maintenance.

  When there is no failure in the LED 7 (No in Step # 6), after Step # 8 and Step # 9, the reading control unit 10 confirms whether failure detection has been performed on all the LEDs 7 (Step # 10). If failure detection has not been performed for all the LEDs 7 (No in step # 10), the lighting control unit 93 turns on the LEDs 7 of even-numbered blocks 77 among the blocks 77 included in the lamp 6 (step # 11). . Also at this time, the LED 7 is turned on by one. Then, the reading control unit 10 operates the winding motor and the image sensor 15 to read the white plate (step # 12). Then, image data is obtained as a reading result (step # 13).

  The reading control unit 10 reads out data indicating the position of the pixel corresponding to the position of the LED 7 in the even block (comparison pixel position information) from the threshold value, the memory 17 and the like (step # 14). Then, based on the read threshold value and the like, the reading control unit 10 compares the pixel value of each pixel (the light amount level of each LED 7) with the threshold value in the image data (step # 15). Thereafter, the process returns to step # 6.

  If the failure detection of all the LEDs 7 has been executed (Yes in step # 10), the reading control unit 10 checks whether there is a failed LED 7 (step # 16). If there is no failed LED 7 (No in step # 16), the process is terminated. On the other hand, if there is a failed LED 7 (Yes in step # 16), the reading control unit 10 reads normally even if there is a failure in the LED 7 included in the lamp 6, based on the position of the LED 7 where the failure is detected. It is confirmed whether or not there is a document size that can be used (step # 17).

  If there is a size of a document that can be read normally even if there is a failure in the LED 7 (Yes in step # 17), the liquid crystal display unit 30 of the operation panel 3 indicates that a failure has occurred in the LED 7, The possible document sizes are displayed (step # 18, see FIG. 9). That is, the image reading apparatus 100 includes a display unit (liquid crystal display unit 30) that displays the size of a readable document when the LED 7 included in the lamp 6 has a failure. On the other hand, if there is no size of the original that can be read normally (No in step # 17), the liquid crystal display unit 30 displays that the LED 7 has failed and that the original cannot be read (step #). 19, see FIG. The failure detection process ends at step # 18 and step # 19.

  As described above, according to the invention of the present embodiment, the failure detection unit (reading control unit 10) determines whether the light amount level of the pixel corresponding to the lit LED 7 is equal to or higher than a predetermined threshold in the image data. A failure of the LED 7 is detected based on the above. Thereby, since the failure detection unit detects whether the LED 7 is turned on or not based on the image data, a measuring instrument (circuit) for measuring the current flowing through the LED 7 is not necessary. Therefore, the manufacturing cost of the image reading apparatus 100 can be reduced, and the design of the image reading apparatus 100 can be simplified. In addition, when the failure is detected, if the LED 7 adjacent to the failed LED 7 (the LED 7 that does not turn on) is lit, the failure may not be detected due to the influence of the irradiation light of the adjacent LED 7. However, according to this configuration, the LED 7 of the other block 77 is arranged between the LED 7 and the LED 7 in the block 77, and at least one of the arranged LEDs 7 is turned on, and the adjacent LED 7 is turned on. It can be turned off. Therefore, the position of the failed LED 7 can be accurately specified.

  The failure detection unit (reading control unit 10) detects whether or not a failure occurs in units of block 77 based on the position of the lit LED 7, and detects whether or not a failure occurs in units of 71 LEDs. . Thereby, when there is a failure, the position of the failed LED 7 can be specified, and a block 77 unit (whether the LED 7 included in the block 77 is turned on) can also be detected. Further, when a failure is detected, the arranged LEDs 7 are turned on one by one. Thereby, at the time of failure detection, the position of the failed LED 7 can be easily specified. Moreover, the failure detection is completed only by changing the combination of the LEDs 7 to be lit once. Therefore, it is possible to accurately identify the failed LED 7 and the block 77 in a short time.

In addition, when the LED 7 breaks down, there is a case where the amount of light is insufficient in a part of the main scanning direction in the maximum size document reading. However, depending on the position of the failed LED 7, the document may be read if the document has a small size that is out of the irradiation range of the failed LED 7. For example, when the LED 7 located at the end in the main scanning direction out of the arranged LEDs 7 fails, the A3 size original cannot be read, but the B5 size or A4 side (the main scanning direction and the A4 short side are aligned). ) May be readable without problems. Therefore, according to this configuration, when there is a failure in LED7 included in the lamp 6, when reading the document placed in accordance with the reference point P on the contact glass 12 for placement reading, the display unit (liquid crystal The display unit 30) displays the size of the readable document. As a result, it is possible to inform the user of a reading method in which there is no deterioration in image quality such as dark streaks due to failure of the LED 7.

  The LED 7 can be a white LED 7. In addition, when reading a document and using image data, image formation that can accurately and quickly detect the position of the failed LED 7 and the block 77 including the LED 7 among the plurality of LEDs 7 included in the lamp 6 as a light source. An apparatus can be provided.

(Second Embodiment)
Next, a second embodiment will be described based on FIG. FIG. 12 is an explanatory diagram showing an example of block division of the lamp 6 according to the second embodiment of the present invention.

  The first embodiment differs from the first embodiment in the way in which the LEDs 7 of the lamp 6 are arranged, but the configuration of the multifunction device 200, the image reading unit 1, the document conveying unit 2, and the like may be the same and common. The description of parts is omitted and the same reference numerals are used.

  FIG. 12 showing the second embodiment shows a relationship between the arrangement of the LEDs 7 in the lamp 6 and the block 77 as in FIG. Also in FIG. 12, a square with a number indicates the LED 7. The numbers in the squares indicate the numbers of the blocks 77 to which the respective LEDs 7 belong.

  Even in the lamp 6 of the second embodiment, one block 77 includes a plurality of LEDs 7 connected in parallel (a series connection may be used). In the description of the second embodiment, an example in which a parallel circuit including three LEDs 7 is handled as one block 77 will be described. Also in the second embodiment, a plurality of blocks 77 are arranged. As a result, a plurality of LEDs 7 are arranged to form one lamp 6. In FIG. 12, the first to ninth blocks 77 are shown as an example.

  However, in the second embodiment, two LEDs 7 in other different blocks 77 are arranged between the LEDs 7 in one block 77. For example, in FIG. 12, the LEDs 7 of the second block and the third block are arranged between the LEDs 7 of the first block. Strictly speaking, between the LEDs 7 of the n + 1 (n ≧ 0) th block 77, one LED7 of the n + 2th and n + 3th block 77 is arranged.

  The lighting circuit 60 as a switch for turning on / off each LED 7 of the lamp 6 turns on the LED 7 of the n + 1 (n ≧ 0) -th block 77 when the failure of the LED 7 is detected. As a result, only the LED 7 of the n + 1 (n ≧ 0) th block 77 is lit. Next, the lighting circuit 60 lights the LED 7 of the n + 2 (n ≧ 0) th block 77. Further, after that, the lighting circuit 60 lights the LED 7 of the n + 3 (n ≧ 0) -th block 77 when the failure of the LED 7 is detected. The position of the failed LED 7 and the failed block 77 are identified by the three lightings. In other words, unlike the first embodiment, failure detection is repeated three times. That is, the lamps 6 are arranged such that two or more LEDs 7 of other blocks 77 are arranged between the LEDs 7 in the block 77, and when a failure is detected, a plurality of the arranged LEDs 7 are skipped. The LED 7 is turned on / off in units of block 77 so that the light is turned on.

  By arranging the two LEDs 7 of the other block 77 between the LEDs 7 of the same block 77 and switching the lighting, the LEDs 7 are lit in two. In other words, when the failure of the LED 7 is detected, the lamps 6 are not lit simultaneously and the two LEDs 7 are lit in two steps. In the normal reading of the original, the lighting circuit 60 lights all the LEDs 7.

  As a basic characteristic, the LED 7 has high directivity of light. Therefore, a member (a diffusing member) for diffusing light, such as a filter, may be provided in the lamp 6 in order to make the light amount level irradiated on the document uniform in the main scanning direction line. Thereby, the bias due to the location of the light intensity level of the irradiation light of the lamp 6 can be eliminated. However, in the failure detection of the LED 7, the surrounding LED 7 supplements the light of the failed LED 7 with the diffusion member, and the failed LED 7 is specified. It may be difficult.

  However, in the second embodiment, the failure can be detected by turning on the LED 7 in two steps. Thereby, even if the surrounding LED 7 can easily supplement the light of the failed LED 7 by the diffusing member, the failed LED 7 can be accurately identified.

  A diffusion member (for example, a filter) for expanding the irradiation angle may be provided in order to eliminate the bias due to the location of the light irradiated from the lamp 6 to the document. Depending on the characteristics of such a diffusing member, it may be difficult to specify the position of the failed LED 7 even if one is skipped. However, according to the invention of the second embodiment, in addition to the effects obtained in the first embodiment, a plurality of the arranged LEDs 7 are lit up at the time of failure detection. Thereby, at the time of failure detection, the arranged LEDs 7 can be turned on at least two times. Therefore, the failed LED 7 and the block 77 can be reliably detected.

  Next, another embodiment will be described. At the time of failure detection, an example in which the LED 7 is turned on by skipping one in the first embodiment and two in the second embodiment has been described. However, three or more LEDs 7 in other different blocks 77 may be arranged between the LEDs 7 in one block 77. At this time, the failure detection is repeated by the number of the LEDs 7 arranged between the LEDs 7 in one block 77 + 1 times.

  In the above embodiment, the example in which the reading control unit 10 performs the failure detection has been described, but the failure detection may be performed by a part other than the reading control unit 10. For example, hardware (dedicated circuit) that executes a failure detection process in the image reading unit 1 is provided as a failure detection unit, and the provided failure detection unit performs failure detection based on image data, threshold values, and comparison pixel position information. May be.

  Alternatively, the main body control unit 8 may perform failure detection. In this case, the threshold value and the comparison pixel position information are stored in the storage unit 82, and the main body control unit 8 reads the image data obtained by reading with the LED 7 turned on every other one or every plurality. Obtained from Part 1. Thus, the main body control unit 8 can also be used as a failure detection unit.

  The embodiment of the present invention has been described above, but the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

  The present invention is applicable to the image reading apparatus 100 and an image forming apparatus including the same.

1 Image Reading Unit 10 Reading Control Unit (Failure Detection Unit)
131 First moving frame (optical system member) 132 Second moving frame (optical system member)
133 Wire (optical system member) 134 Winding drum (optical system member)
14 Lens (optical system member) 15 Image sensor 161 First mirror (optical system member) 162 Second mirror (optical system member)
163 Third mirror (optical system member) 30 Liquid crystal display unit (display unit)
6 lamp 7 LED
77 Block 8 Control unit (Fault detection unit)
DESCRIPTION OF SYMBOLS 100 Image reading apparatus 200 Multifunction machine (image forming apparatus)

Claims (6)

A lamp in which LEDs are arranged in such a manner that a plurality of blocks each including a plurality of LEDs are included, and LEDs in other blocks are arranged between the LEDs in the block,
An image sensor that is irradiated from the lamp, reflected by a reading target, and incident by light guided by an optical member, and at least reads the reading target in units of lines;
A failure detection unit for detecting a failure of the LED included in the lamp;
A display unit for displaying a failure detection result and a status display,
When performing failure detection to detect a failure of an LED included in the lamp,
The lamp is switched on / off in units of blocks so that the arranged LEDs are lit at least once.
The failure detection unit detects a failure of the LED based on whether or not the light level of the pixel corresponding to the lit LED is equal to or higher than a predetermined threshold in the image data based on the output of the image sensor,
Wherein the display unit, when there is a failure in the LED included in the lamp, when reading the document placed in accordance with the reference point on the contact glass placement reading, displaying a size of readable document A characteristic image reading apparatus.
  The failure detection unit detects whether or not a failure occurs in units of blocks based on the position of the lit LED, and / or detects whether or not a failure occurs in units of one LED. The image reading apparatus according to claim 1.   The LED is arranged such that one LED in another block is arranged between the LEDs in the block, and the LEDs arranged in the block are turned on one by one when the failure is detected. The image reading apparatus according to claim 1, wherein the LED is switched on and off in units of blocks.   The lamps are arranged so that two or more LEDs of other blocks are arranged between the LEDs in the block, and when the failure is detected, a plurality of arranged LEDs are lit in a blinking manner. The image reading apparatus according to claim 1, wherein the LED is switched on and off in units of blocks. The LED includes an image reading apparatus according to any one of claims 1 to 4, characterized in that a white LED. An image forming apparatus comprising an image reading apparatus according to any one of claims 1 to 5.

Images