JP2016072750A - Image reading apparatus and dust detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading apparatus capable of determining whether or not cleaning of dust is finished in a state where an ADF unit is opened when cleaning the dust or dirt on an original reading glass, and obtaining an excellent image reading.SOLUTION: An image reading apparatus comprising: an ADF unit which can open and close to a glass on to which an original is placed for image reading; and reading means for performing photoelectric conversion to a reflected light obtained by irradiating the original with light and generating an image signal, performs a following processing. In a state where the ADF unit is closed, the image reading apparatus detects whether or not dust is attached on to the glass based on the image signal obtained by operating the reading means. If the dust attachment is detected, the image reading apparatus informs a user to clean the glass. In accordance with the information, the image reading apparatus detects whether or not dust on glass is removed based on the image signal obtained by the reading means in the state where the ADF unit is opened. If it is detected that the dust is removed, the image reading apparatus informs completion of cleaning to the user.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an image reading apparatus and a dust detection method, and more particularly, for example, an image reading apparatus and a dust detection function having a function of cleaning dust and dirt attached on a platen glass on which an optically read document is placed. Regarding the method.

In an image reading apparatus equipped with a conventional automatic document feeder (ADF), with an optical unit for irradiating light on a document being stopped at a predetermined position, documents are fed one by one at a constant speed by ADF. An apparatus having a “flow-reading mode” for reading a document is known. In this “flow-reading mode”, it is only necessary to feed a document in a certain direction. Therefore, when a large number of documents are continuously read, the document reading time is shorter than the operation of scanning the optical unit to read the document. There is an advantage.
When a document is read in such “flow-reading mode”, if there is dust or dirt on the document reading position on the platen glass, black streaks occur at the position of the scanned image corresponding to that position. . Therefore, in order to prevent the occurrence of black streaks, a method has been proposed in which dust adhering to the platen glass is detected and the user is prompted to clean the glass.

JP 2001-144901 A JP 2006-129162 A JP 2007-104444 A

  However, in the above conventional example, it is necessary for the user to determine whether or not the cleaning is completed after the user has cleaned the dust adhering to the platen glass. For this reason, even if the cleaning is not performed normally, the glass cleaning ends depending on the judgment of the user, and black streaks may still occur in the image obtained by the subsequent reading operation.

  In addition, it is necessary to once close the ADF in order to determine again whether there is dust and to confirm whether or not normal cleaning has been performed. This is troublesome for the user.

  The present invention has been made in view of the above-described conventional example, and can confirm that dust and dirt on the platen glass have been cleaned without bothering the user and can perform good image reading. An object of the present invention is to provide an image reading apparatus and a dust detection method thereof.

  In order to achieve the above object, the recording apparatus of the present invention has the following configuration.

  That is, an image reading apparatus including an ADF unit that is openable and closable with respect to a glass on which the document is placed in order to read an image of the document. A reading unit that receives the reflected light and photoelectrically converts the reflected light to generate an image signal; and a dust on the glass based on the image signal obtained by the reading unit with the ADF unit closed. A first detection means for detecting whether or not a dust is attached, and a notification for prompting a user to clean the glass when the first detection means detects that the dust is attached. In response to the notification from the first notification means and the first notification means, it is detected whether the dust has been removed based on the image signal obtained by the reading means with the ADF unit opened. A second detection means that, when the can dust has been removed by the second detection means is detected, and having a second notifying means for notifying the completion of the cleaning to the user.

  In another aspect of the present invention, an ADF unit that can be opened and closed with respect to a glass on which an original is placed for image reading, and irradiating the original with light and receiving reflected light from the original. And a dust detection method for an image reading apparatus comprising a reading means for photoelectrically converting the reflected light to generate an image signal, wherein the image signal obtained by the reading means in a state in which the ADF unit is closed A first detection step for detecting whether or not dust is attached to the glass, and cleaning the glass when it is detected that dust is attached in the first detection step. In response to the notification in the first notification step, the first notification step for notifying the user and the image signal obtained by the reading means in a state where the ADF unit is opened is used. A second detection step for detecting whether or not the dust has been removed, and a second notification step for notifying the user of the end of cleaning when it is detected that dust has been removed in the second detection step. A dust detection method is provided.

  Therefore, according to the present invention, it is possible to determine whether or not the dust cleaning has been normally completed in real time while the user is cleaning, so that black streaks are generated in the read image by performing the image reading with the dust attached. Therefore, high-quality image reading can be realized.

1 is a side sectional view showing a configuration of an image reading apparatus that is a typical embodiment of the present invention. It is a figure which shows the relationship between a manuscript, a flow reading glass, and a reading position, and the image obtained by reading a manuscript. It is a block diagram which shows the control structure of an image reading apparatus. It is a flowchart which shows the dust detection process of a flow-reading glass. It is a figure which shows the relationship between the luminance value of the image data obtained by reading a white reading roller through a flow reading glass, and the position of a main scanning direction. It is a flowchart which shows the dust removal judgment process in cleaning mode. It is a timing chart of various signals used for LED lighting control. FIG. 6 is a diagram illustrating a relationship between a luminance value of image data obtained by first one-line reading after selecting a cleaning mode and a position in a main scanning direction. , It is the figure which showed the relationship between the brightness | luminance value of the image data acquired when a user wipes a wiping cloth and presses against reading glass, and the position of a main scanning direction.

  Hereinafter, preferred embodiments of the present invention will be described more specifically and in detail with reference to the accompanying drawings.

  In this specification, “recording” (sometimes referred to as “printing”) is not limited to the case of forming significant information such as characters and graphics, but may be significant. It also represents the case where an image, a pattern, a pattern, etc. are widely formed on a recording medium, or the medium is processed, regardless of whether it is manifested so that humans can perceive it visually. .

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  FIG. 1 is a side sectional view showing the structure of an image reading apparatus that optically reads an image of a document according to a typical embodiment of the present invention. The image reading apparatus shown in FIG. 1 includes a scanner unit 1 and an ADF unit 7.

  The ADF unit 7 is connected at the end of the scanner unit 1 and is openable and closable. By opening the ADF unit 7, the original can be placed on the original platen glass 14, and the original can be read. The ADF unit 7 is provided with a document tray 72. When a plurality of documents 74 are placed on the document tray 72, the scanner unit 1 continuously feeds the documents by feeding them one by one. Image reading can be performed. The scanner unit 1 uses the CIS unit 13 to irradiate light on a document, receive light reflected from the document, and photoelectrically convert the light to generate an image signal. In this way, image data is generated by reading an image of a document.

  The CIS unit 13 includes an illumination unit 131, an optical lens 133, and an imaging unit 134, and is disposed on the side opposite to the document placement side so as to be in close contact with the document table glass 14 or the flow reading glass 15. The illuminating unit 131 includes a white light guide tube provided with three of a blue LED, a green LED, and a red LED as a light source, and the blue LED, the green LED, and the red LED are inclined at different angles with respect to the document table glass 14. Illuminate the document from.

  The optical lens 133 is composed of a SELFOC (registered trademark) lens or the like, and guides the light emitted from the illumination unit 131 and reflected by the document surface to a predetermined imaging position, and the reflected light from the document is magnified by an equal magnification. Read with.

  The imaging unit 134 includes a plurality of photoelectric conversion elements arranged in a predetermined direction, and images light guided to a predetermined imaging position by the optical lens 133. In this embodiment, it is assumed that the imaging unit 134 is a CMOS sensor. Document image data obtained by imaging by the imaging unit 134 is stored in an image storage unit (described later). The CIS unit 13 having such a configuration is attached to the drive belt 16, and the driving force of the scanner motor 18 is transmitted through the drive belt 16, so that the arrow H direction (sub-scanning direction) along the guide rail 17. Moving.

  In the scanner unit 1, the CIS unit 13 is moved in the sub-scanning direction H by the driving force of the scanner motor 18, and the CIS unit 13 is electrically moved in the direction perpendicular (generally intersecting) to the drawing (main scanning direction). The image of the original is read by scanning. In general, a stepping motor, a DC motor, or the like is used as the scanner motor 18. Further, at the time of image reading, the white reference plate 12 provided at the end of the platen glass 14 is irradiated with light, and a reference signal for performing shading correction is obtained from the reflected light. Usually, the arrangement direction of a plurality of photoelectric conversion elements corresponds to the main scanning direction.

  The ADF unit 7 feeds a plurality of documents 74 set on the document tray 72 with the surface facing upward from the uppermost document to the separation unit 732 by the pickup roller 731. The separation unit 732 has a separation roller on the upper side and a separation pad on the lower side, and separates a plurality of documents 74 from the uppermost sheet one by one. The separated original is subjected to skew correction generated during separation and conveyance by the registration roller 733, and then conveyed from the registration roller 733 by the registration roller 734 and the conveyance roller 735. Further, the separated document passes through a flow reading position (described later), and is sequentially discharged from the transport roller 736 onto the discharge tray 73 by the transport roller 737 and the discharge roller 738 with the document surface facing downward. A white reading roller 71 is provided between the conveyance roller 735 and the conveyance roller 736.

  On the scanner unit 1 side, the CIS unit 13 is moved to read a predetermined position (reading position R) of the flow reading glass 15, and the image on the original conveyed at a constant speed is read by the ADF unit 7 as described above. A predetermined position on the flow reading glass 15 being read by the scanner unit 1 is referred to as a “flow reading position”.

  FIG. 2 is a diagram showing the relationship between the document, the flow reading glass, and the reading position, and an image obtained by reading the document. FIG. 2A shows the relationship between the original, the flow reading glass, and the reading position, and FIG. 2B shows an image obtained by reading the original.

  In FIG. 2A, a broken line R indicates a reading position at a predetermined position on the flow reading glass 15. The document is moved and conveyed by an automatic document feeder (ADF) in the direction indicated by the broken line arrow in FIG. In the case of image reading in the flow reading mode, if dust or dirt 801 is present at the reading position R of the flow reading glass 15 as shown in FIG. 2A, the reading position is moved to that reading position as shown in FIG. A black streak 803 is generated at the position of the corresponding image in the main scanning direction.

  FIG. 3 is a block diagram showing a control configuration of the image reading apparatus.

  In the CIS unit 13, the LED driving circuit (driver) 3 performs light amount adjustment of the illumination unit 131 for each line in the main scanning direction to control the lighting time of the LED, and reads an image of a document. The LED drive circuit 3 can turn on each of the blue LED 1311, the green LED 1312, and the red LED 1313 included in the illumination unit 131 with an arbitrary PWM duty.

  The amplifier (AMP) 21 amplifies the electrical signal output from the CIS unit 13, and the A / D conversion circuit 22 A / D converts the amplified electrical signal, for example, converts each color component of each pixel to 16 bits. A digital image signal expressed as a luminance value is output. A configuration necessary for A / D conversion including the A / D conversion circuit 22 is collectively referred to as a conversion unit.

  The image signal detected by the imaging unit 134 is input to the A / D conversion circuit 22 in a line sequential manner and in synchronization with a synchronization signal in the main scanning direction because the blue LED 1311, the green LED 1312, and the red LED 1313 are sequentially turned on. . The display unit 53 is composed of, for example, an LCD, and can receive warnings and notifications to the user by receiving instructions from the CPU 5 on the screen.

  The image processing unit 6 performs image processing on the digital image signal converted by the A / D conversion circuit 22. The memory 61 stores image data obtained by image processing, and transfers images by connecting to an interface with a printer that employs an inkjet method or an electrophotographic method, or an external device. Information about dust and dirt is also stored in the memory 61.

  The timing generation circuit 4 can vary the PWM duty for each line in the main scanning direction according to the setting of the CPU 5, and adjusts the light amount of the LED by sending an LED ON / OFF control signal to the LED drive circuit 3. It is carried out. The CPU 5 includes a ROM 52 that stores a program executed by the CPU 5 and a RAM 51 that is used as a work area for executing the program.

  The motor drive circuit 91 can rotate the scanner motor 18 according to the setting of the CPU 5, and can move the CIS unit 13 at a constant speed. Further, the motor drive circuit 92 rotates the ADF motor 75 according to the setting of the CPU 5 and conveys the original set on the ADF unit 7. The ADF open / close sensor 19 changes the output signal according to the state of the open / close section connected to the ADF unit 7 and the end of the scanner unit 1, and outputs it to the open / closed state of the ADF unit 7.

  Next, processing up to dust detection executed by the image reading apparatus having the above configuration will be described.

  FIG. 4 is a flowchart showing dust detection processing of the flow-reading glass.

  If image reading is selected by the user, it is checked in step S101 whether reading using the ADF unit 7 is selected. If reading is selected using the ADF unit 7, the process proceeds to step S102. On the other hand, when reading without using the ADF unit 7 is selected, since reading is not performed below the flow reading glass 15, dust detection is not necessary, and the process ends.

  In step S102, the ADF opening / closing sensor 19 is used to check whether the ADF unit 7 is in a closed state. If it is determined that the ADF unit 7 is closed, the process proceeds to step S103. On the other hand, if it is determined that the ADF unit 7 is open, it is difficult to read dust, and the process ends.

  In step S103, the lighting control of each of the blue LED 1311, the green LED 1312, and the red LED 1313 is performed so that the image can be read. In step S104, the CIS unit 13 is moved to the lower part of the white reference plate 12, and in step S105, a reference signal for performing shading correction is obtained from the reflected light. In step S106, the CIS unit 13 is moved to the reading position R for flow reading. In step S107, the white reading roller 71 is read through the flow reading glass 15, and the image data is acquired.

  FIG. 5 is a diagram showing the relationship between the luminance value of the image data obtained by reading the white reading roller 71 through the flow reading glass 15 in step S107 and the position in the main scanning direction.

  FIG. 5A shows the relationship between the luminance value of the image data and the main scanning direction when dust does not adhere to the flow reading glass 15. In this case, since the white reading roller 71 can be normally read, the image data luminance value exceeds the preset dust detection threshold Ls1 in any of the main scanning directions.

  On the other hand, FIG. 5B shows the relationship between the luminance value of the image data and the main scanning direction when dust adheres to the flow reading glass 15. In this case, since the dust information is read, the luminance value is lowered only for the dust adhesion position. The example of FIG. 5B shows that the brightness value of the image data at each position falls below the dust detection threshold Ls1 when dust is attached at two locations.

  Returning to FIG. 4, the description is continued. In step S108, it is checked whether or not there is one or more image data equal to or less than the dust detection threshold Ls1 in the luminance value of the image data obtained by reading the white reading roller 71. If there is no dust, there is no image data whose luminance value is less than or equal to the dust detection threshold in step S108, so the determination result is “No” and the process ends. On the other hand, when there is dust, there is one or more image data whose luminance value is equal to or less than the dust detection threshold Ls1, and the process proceeds to step S109.

In step S109, the main scanning position of the image data whose luminance value is equal to or smaller than the dust detection threshold Ls1 is stored. In the example of FIG. 5B, the luminance values of the two pieces of image data with the dust detection threshold Ls1 = 80 or less are two, L ₁ = 10 and L ₂ = 40, respectively. In step S109, the main scanning positions X ₁ = 1000 and X ₂ = 3000 where the two image data existed are stored in the memory 61. When n image data having a luminance value lower than the dust detection threshold Ls1 is present, n main scanning positions (X _{1 to} X _n ) are stored according to the number of image data.

  In step S110, a message is displayed on the screen of the display unit 53 to warn the user that dust is attached. At that time, a message prompting the user to switch to the cleaning mode is displayed. In step S111, it is checked whether or not the user has selected the cleaning mode. If the user has not selected the cleaning mode, the process ends without shifting to the cleaning mode. On the other hand, when the user selects the cleaning mode, the process proceeds to step S112, shifts to the cleaning mode, and then the dust detection process ends.

  Next, processing up to the dust removal determination in the cleaning mode will be described with reference to FIGS.

  FIG. 6 is a flowchart showing the dust removal determination process in the cleaning mode.

  First, in step S201, a display prompting the user to open the ADF unit 7 is displayed using the display unit 53. In step S202, it is checked whether the ADF unit 7 is open based on the output signal from the ADF open / close sensor 19. If it is determined that the ADF unit 7 is closed, the process returns to step S201, and the display prompting the user to open the ADF unit 7 is continued until the ADF unit 7 is opened. On the other hand, if it is determined that the ADF unit 7 has been opened, the process proceeds to step 203 to move the CIS unit 13 to the reading position R.

  FIG. 7 is a timing chart of various signals used for LED lighting control.

  7A shows LED lighting control during normal reading of a black and white image, FIG. 7B shows LED lighting control in the cleaning mode, and FIG. 7C shows LED lighting control at the end of cleaning. Each is shown.

  Returning to FIG. 6, the description will be continued. In step S204, the LED is controlled to be lit in the cleaning mode.

  In the LED lighting control during normal reading of a black and white image, each of the blue LED 1311, the green LED 1312, and the red LED 1313 is controlled to light up simultaneously in one line section. As shown in FIG. 7A, the lighting control signals LED_B, LED_G, and LED_R corresponding to these LEDs become high level in synchronization with the synchronizing signal HSYNC indicating one line section, and the three LEDs are simultaneously lit. To do.

  On the other hand, in the lighting control of the LED in the cleaning mode, as shown in FIG. 7B, the blue LED 1311 and the green LED 1312 are controlled to reduce the lighting frequency with respect to the red LED 1313. Specifically, the lighting control signals LED_B and LED_G are controlled so that the frequency at which the lighting control signals LED_B and LED_G are at the high level is 1/3 of the frequency at which the lighting control signal LED_R is at the high level. In other words, the lighting duty of the blue LED 1311 and the green LED 1312 is about 33% of the red LED 1313. As a result, the blue LED 1311, the green LED 1312, and the red LED 1313 are simultaneously turned on every three lines, and only the red LED 1313 is turned on otherwise. By performing such control, the user can visually see the LED light in a color close to red. In the cleaning mode, it is necessary to perform accurate dust detection based on the acquired image data. Therefore, when only the red LED 1313 emits light, control is performed so as not to output an image signal to the image processing unit 6.

In step S205, image reading for one line is performed and image data corresponding to this is acquired. At this time, as described above, the image data when the blue LED 1311, the green LED 1312, and the red LED 1313 are simultaneously lit is acquired. In step S206, the average luminance value L _AVE1 is calculated from the image data for the first line obtained by reading.

  FIG. 8 is a diagram showing the relationship between the luminance value of the image data obtained by the first one-line reading after the cleaning mode is selected and the position in the main scanning direction.

Since the ADF unit 7 is open before the user starts wiping, the reflected light of the irradiation light from the LED does not enter the imaging unit 134. Therefore, as shown in FIG. 8, the luminance value is a low value as a whole. That is, the amount of light received by the photoelectric conversion element of the imaging unit 134 decreases as a whole. In the example shown in FIG. 8, the values are large at the _two positions X ₁ and X ₂ in the main scanning direction, but the luminance values obtained at all the positions are less than the dust removal threshold L _s2 . These specific positions and the luminance values at those positions are as shown in FIG. At this time, the acquired average luminance value is L _AVE1 = 8.6, and L _AVE1 = 8.6 is stored in the memory 61 as the average luminance value of the first one line of image data.

In step S207, an image for one line is read in order to confirm whether dust has been removed and whether the user has started wiping. In step S208, the average brightness L _AVE1 obtained first is compared with the average brightness value L _AVE of the image data obtained by image reading for one line in step S207. Here, when there is no luminance difference of 5 or more with _respect to L _AVE1, that is, when | L _AVE −L _AVE1 | <5, it is determined that the user is not wiping off. In this case, the process proceeds to step S210, and it is checked whether or not 3 minutes or more have passed since the image reading was started.

If it is determined that three minutes or more have elapsed since the start of image reading, the process proceeds to step S211, a time-out is notified to the user using the display unit 53, and the cleaning mode ends. This is a process for automatically terminating the cleaning mode when wiping by the user has not been performed for a long time. On the other hand, if it is determined that 3 minutes or more have not elapsed since the start of image reading, the process returns to step S207 and image reading is performed again. In this way, the process is repeated until the average luminance value L _AVE becomes a difference of 5 or more with respect to the average luminance value L _AVE1 obtained first.

  9 to 10 are diagrams showing the relationship between the luminance value of the image data acquired when the user presses the wiping cloth against the reading glass 15 and the position in the main scanning direction.

When the wiping cloth is pressed as shown in FIG. 9, the luminance value increases because the reflected light reflected by the wiping cloth is incident on the imaging unit 134 only in the pressed portion. Along with this, the average luminance value rises to L _AVE = 45.7.

If | L _AVE −L _AVE1 | ≧ 5 in step 208, the process proceeds to step S 209 to check whether the luminance value at the dust detection position exceeds the dust removal threshold L _S2 .

In the example shown in FIG. 9, it has a luminance value L ₁ = 10, the luminance value L ₂ = 37 separate dust detection position X ₂ of the dust detection position X _1. Since these luminance values are respectively lower than the dust removal threshold L _S2 = 120, in this case, the process returns to step S207 according to the determination in step S209. Here, as shown in Figure 9, if not possible dust removal in the main scanning direction of the position X ₁ attached to the glass 15 flow reading, the luminance value even if pressed wiping cloth is rise Because there is no such result.

On the other hand, in the example shown in FIG. 10, the luminance values at the dust detection positions X ₁ and X ₂ corresponding to FIG. 9 are L ₁ = 240 and L ₂ = 37. When these values are compared with the dust removal threshold value L _S2 , the luminance value L _{1 at the} position X ₁ exceeds L _S2 . This means that the dust at position X ₁ has been removed by wiping, and as a result, the luminance value at that position has increased. Therefore, in this case, it is determined that dust has been removed, and the process proceeds to step S212.

In step S212, it is stored in the memory 61 which position from X _{1 to} X _n the dust detection position where the luminance value exceeding the dust removal threshold L _S2 was obtained. In the example shown in FIG. 10, the luminance value L _{1 at} the dust detection position X ₁ is stored in the memory 61 on the assumption that it exceeds the dust removal threshold L _S2 . In step S213, it is checked whether the luminance values at all dust detection positions X _{1 to} X _n exceed the dust removal threshold L _S2 . Here, if it is determined that all the luminance values at the dust detection position do not exceed the dust removal threshold value, the process returns to step S207, and the above process is repeated. On the other hand, if it is determined that the luminance values at all dust detection positions exceed the dust removal threshold, the process proceeds to step S214.

  In step S214, in order to notify the user that the cleaning is completed, a message indicating the completion of the cleaning is displayed on the display unit 53, and the manner in which the LED of the CIS unit 13 is lit is changed. Specifically, as shown in FIG. 7C, the blue LED 1311 and the red LED 1313 are turned off, and only the green LED 1312 is turned on. With such control, the entire light emission duty of the blue LED 1311, the green LED 1312, and the red LED 1313 is about 33%, and only the light emission color of the LED is changed while the total light amount is low. As a result, the user visually perceives that the color of the LED has changed from red to green, so that the user can recognize that the cleaning has ended without wiping the flow-reading glass 15 and looking at the display unit 53.

  In step S215, it is checked whether the ADF unit 7 is closed based on the output signal from the ADF open / close sensor 19. If it is determined that the ADF unit 7 is closed, the process proceeds to step S216, the LED is turned off, and the cleaning mode ends. On the other hand, if the ADF unit 7 remains open, the process returns to step S214, and the user is notified of the end of cleaning.

  Therefore, as described above, according to the embodiment, in the cleaning mode, the image data obtained from the flow reading glass is analyzed to determine that the dust has been removed, and the end of the cleaning is displayed as a message on the display unit. Notification is made by changing the color of the LED to be lit. Thus, even when the ADF unit is open, the user can know the end of cleaning. At this time, as a method of notifying the end of the cleaning, either the message display or the LED color change may be used. Further, instead of changing the color of the LED, for example, the LED lighting method may be changed so as to blink the LED.

  In the embodiment described above, a single-function image reading device (scanner) has been described as an example, but the present invention is not limited thereto. For example, the present invention can also be applied to a copying machine, a facsimile machine, or another multifunction machine in which the image reading apparatus includes an image forming unit and a facsimile communication unit.

3 LED drive circuit, 4 timing generation circuit, 5 CPU, 6 image processing unit,
7 Automatic document feeder (ADF unit), 12 White reference plate, 13 CIS unit,
15 flow reading glass, 19 ADF open / close sensor, 21 amplifier,
22 A / D conversion circuit, 53 display unit, 61 memory, 71 white reading roller,
731 Pickup roller, 732 Separation part, 733-734 Registration roller,
735-737 Conveying roller, 738 Discharging roller,
1311 Blue LED, 1312 Green LED, 1313 Red LED

Claims (12)

An image reading apparatus comprising an ADF unit that can be opened and closed with respect to a glass on which the document is placed in order to read an image of the document,
Reading means for irradiating the original with light, receiving reflected light of the light from the original, and photoelectrically converting the reflected light to generate an image signal;
First detection means for detecting whether dust is attached to the glass based on an image signal obtained by the reading means in a state where the ADF unit is closed;
First notification means for notifying a user to clean the glass when the first detection means detects that dust is attached;
Second detection means for detecting whether or not the dust has been removed based on an image signal obtained by the reading means in a state where the ADF unit is opened in response to the notification by the first notification means; ,
An image reading apparatus comprising: a second notification unit that notifies the user of the end of cleaning when the second detection unit detects that dust is removed.   The display device further includes a display unit that displays a notification prompting the user to clean the glass by the first notification unit, and displays a notification that the cleaning is completed to the user by the second notification unit. The image reading apparatus according to claim 1.   3. The image reading according to claim 1, wherein the second notifying unit notifies the user of the end of cleaning when the reading unit emits light different from that when reading the document. apparatus. Moving means for moving the reading means in a predetermined direction;
4. The storage device according to claim 1, further comprising a storage unit that stores a position on the glass at which the first detection unit detects that dust is attached. 5. Image reading apparatus.   The glass is a glass provided at a predetermined position in a direction in which the reading unit moves by the moving unit for continuous reading, in which a plurality of documents fed by the ADF unit are continuously read. The image reading apparatus according to claim 4, wherein the image reading apparatus is provided. The reading means includes
A plurality of light sources for irradiating the original with light;
An optical lens that guides reflected light emitted from the plurality of light sources and reflected by the document to a predetermined imaging position;
A plurality of photoelectric conversion elements which are arranged in a direction different from the moving direction of the reading means by the moving means and which convert the reflected light guided by the optical lens into an electric signal. The image reading apparatus according to claim 4 or 5.   The image reading apparatus according to claim 6, wherein the plurality of light sources include a red LED, a green LED, and a blue LED.   Whether the red LED, the green LED, and the blue LED are simultaneously turned on when the document is read by the reading unit with respect to the plurality of light sources, and whether the dust is removed by the second detection unit. Is detected so that the light emission duty of the green LED and the blue LED is smaller than the light emission duty of the red LED, and when the notification is made by the second notification means, The image reading apparatus according to claim 7, further comprising a lighting control unit that controls to turn off the LED and the blue LED and to turn on the green LED. The first detection means includes
First comparison means for comparing the luminance value of the image signal obtained by the reading means with the ADF unit closed with a predetermined first threshold;
And a first determination unit configured to determine that dust is attached when a luminance value of the image signal compared by the first comparison unit is equal to or less than the first threshold value. Item 9. The image reading apparatus according to any one of Items 6 to 8. The second detection means includes
Second comparing means for comparing the luminance value of the image signal obtained by the reading means with the ADF unit opened to a predetermined second threshold;
7. A second determination unit that determines that dust has been removed when the luminance value of the image signal compared by the second comparison unit is greater than the second threshold value. 10. The image reading device according to any one of items 1 to 9. Image signals obtained by driving the reading means are acquired at a plurality of positions in the arrangement direction of the plurality of photoelectric conversion elements,
10. The position on the glass where the dust stored in the storage means is detected is a position in the arrangement direction of the plurality of photoelectric conversion elements. The image reading apparatus described. An ADF unit that can be opened and closed with respect to a glass on which an original is placed for image reading, and irradiating the original with light, receiving reflected light from the original, and photoelectrically converting the reflected light to generate an image. A dust detection method for an image reading apparatus comprising a reading means for generating a signal,
A first detection step of detecting whether dust is attached to the glass based on an image signal obtained by the reading unit in a state where the ADF unit is closed;
A first notification step for notifying a user to clean the glass when it is detected that dust is attached in the first detection step;
A second detection step of detecting whether or not the dust has been removed based on an image signal obtained by the reading means in a state where the ADF unit is opened in response to the notification in the first notification step; ,
A dust detection method comprising: a second notification step of notifying the user of the end of cleaning when it is detected in the second detection step that dust is removed.

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