JP6926783B2 - Image reader and image forming device equipped with it - Google Patents

Description

The present invention relates to an image reading device for scanning and reading a document used in a digital copier, an image scanner, or the like, and an image forming device including the same.

Conventionally, in an image reading device mounted on a multifunction device or the like using an electrophotographic process, a sheet-shaped document is sequentially sent to a document mounting table (contact glass) in order to be read, and is ejected from the document mounting table after scanning is completed. Some are equipped with such an Automatic Document Feeder. In such an image reading device, a sheet-through method is used in which the document is automatically conveyed and read by the document conveying device with the scanning module fixed at the image scanning position, and a document retainer is opened and closed each time the document is read. Two types of scanning methods are possible: a document fixing method in which the scanning module is scanned and moved to scan the documents placed on the document mounting table while the documents on the mounting table are replaced one by one.

In recent years, in the above-mentioned sheet-through method, a double-sided simultaneous reading method in which the front side and the back side of a double-sided document are simultaneously read by using different reading modules in one document transporting operation by a document transporting device has become mainstream. The scanning module that reads the back side of the double-sided document is arranged on the document transfer device side. Further, the document transport device is provided with a cover member capable of opening a part of the document transport path for jamming the document.

Further, in the image reading device, there are various processes necessary for initial setting and adjustment of the reading module, and one of the processes is that the light source mounted on the reading module in the initial state such as when the image reading device is assembled. There is a light amount adjustment process for adjusting the light amount.

On the other hand, in the double-sided simultaneous reading type image reading device, a reading module for reading the back side of the double-sided document is arranged at the opening / closing part of the cover member in consideration of the space in the document conveying device and the convenience of cleaning the reading position. The configuration is known. Then, the white reference plate is attached to the cover member side with the document transport path interposed therebetween, and when the cover member is opened, the reading module and the white reference plate are separated from each other.

In the above configuration, since the reading module cannot receive the reflected light from the white reference plate when the cover member is open, it is conceivable that the amount of light is adjusted to the upper limit. As a result, when the image is read, the sensor receives saturation due to an excessive amount of light, and a reading abnormality occurs. Alternatively, since the reading module receives ambient light when the cover member is open, it is conceivable that the amount of light is adjusted in the lower limit direction. As a result, the light source is not lit when the image is read, or the sensor reading failure occurs due to insufficient light intensity.

Patent Document 1 discloses an image reading device that determines whether or not an image can be read according to the open / close detection result of the document transporting device for the image reading device and the intensity of the external light detected by the external light detecting means. ing.

Japanese Unexamined Patent Publication No. 2011-77648

However, the method of Patent Document 1 determines whether or not the image reading operation can be executed based on the open / closed state of the document transporting device with respect to the image reading device main body and the intensity of external light, and adjusts the amount of light of the light source of the reading module. The relationship between the treatment and the opening and closing of the cover member was not disclosed.

In view of the above problems, the present invention is an image reading device capable of preventing adjustment failure due to opening and closing of a cover member when performing light amount adjustment processing of a light source of a reading module arranged in a document transporting device, and an image provided with the image reading device. It is an object of the present invention to provide a forming apparatus.

In order to achieve the above object, the first configuration of the present invention is an image reading device including a document transporting device, a first reading module, and a control unit. The document transport device transports documents. The first scanning module is arranged in the document transporting device and can read the image of the transported document transported by the document transporting device. The control unit controls the first reading module. The document transfer device is arranged on a document transfer path through which the transfer document passes, a cover member capable of opening and closing a predetermined section of the document transfer path, and a white cover member facing the first reading module in a closed state. It has a reference plate and. The first reading module includes a light source composed of LEDs of one or more colors, and a sensor that reads the reflected light of the light from the light source as image light. The control unit lights each LED one color at a time with the white reference plate facing each other, acquires light intensity data by the sensor, and adjusts the light intensity by changing the lighting time width of each LED based on the acquired light intensity. It is possible to perform PWM adjustment. When executing PWM adjustment, the control unit lights one color of the LED after the first open / close determination process for determining the open / closed state of the cover member and the first open / close determination process determine that the cover member is in the closed state. It is determined that the cover member is in the closed state by the light amount adjustment process for executing the PWM adjustment, the second open / close determination process for determining the open / closed state of the cover member again after the light amount adjustment process, and the second open / close determination process. After that, the adjustment confirmation process for determining whether or not the amount of light satisfies a predetermined condition is sequentially executed for the LEDs of all colors.

According to the first configuration of the present invention, when the PWM adjustment of the light source of the first reading module is executed, the closed state of the cover member is determined before and after the light amount adjustment of each LED. Then, when the cover member is opened before the light amount adjustment, the light amount is not adjusted, and even if the cover member is closed before the light amount adjustment, when the cover member is opened after the light amount adjustment, the adjustment confirmation process is performed. Readjust the amount of light without doing it. Therefore, the PWM adjustment can be performed in a state where the cover member is securely closed, and reading abnormality due to excess or deficiency of the amount of light can be prevented.

Side sectional view showing the overall configuration of the image forming apparatus 100 provided with the image reading unit 6 of the present invention. A side sectional view showing an internal structure of a document transporting device 27 that automatically transports a document to an image reading unit 6 and an image reading unit 6 according to an embodiment of the present invention. Partial enlarged view showing the structure inside the cover member 31 of the document transport device 27 in FIG. Partial enlarged view around the back surface reading module 50 and the back surface white reference plate 55 in FIG. A flowchart showing a control example in the case of performing PWM adjustment of the light source 70 of the back surface reading module 50 in the document transporting device 27 of the present embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an image forming apparatus 100 provided with the image reading unit 6 of the present invention. In FIG. 1, in the image forming apparatus 100 (here, a digital multifunction device is shown as an example), when performing a copy operation, the image reading unit 6 described later converts the image data of the original into a reading image signal. On the other hand, in the image forming unit 3 in the main body 2 of the multifunction device, the photoconductor drum 5 rotating in the clockwise direction in the drawing is uniformly charged by the charging unit 4. Then, the laser beam from the exposure unit (laser scanning unit or the like) 7 forms an electrostatic latent image based on the original image data read by the image reading unit 6 on the photoconductor drum 5. A developer (hereinafter referred to as toner) is adhered to the formed electrostatic latent image by the developing unit 8 to form a toner image. Toner is supplied to the developing unit 8 from the toner container 9.

Paper is conveyed from the paper feeding mechanism 10 to the image forming unit 3 via the paper conveying path 11 and the resist roller pair 12 toward the photoconductor drum 5 on which the toner image is formed as described above. The conveyed paper passes through the nip portion of the photoconductor drum 5 and the transfer roller 13 (image transfer portion), so that the toner image on the surface of the photoconductor drum 5 is transferred. Then, the paper on which the toner image is transferred is separated from the photoconductor drum 5 and conveyed to the fixing portion 14 having the fixing roller pair 14a to fix the toner image. The paper that has passed through the fixing portion 14 is transported to the paper transport path 15 that is branched in a plurality of directions. The paper is sorted in the transport direction by the route switching mechanisms 21 and 22 having a plurality of route switching guides provided at the branch points of the paper transport path 15, and is sent as it is (or sent to the reverse transport path 16 and copied on both sides). ), The paper is discharged to the paper ejection section including the first ejection tray 17a and the second ejection tray 17b.

Further, although not shown, a static eliminator for removing residual charges on the surface of the photoconductor drum 5 is provided on the downstream side of the cleaning device 18 with respect to the rotation direction of the photoconductor drum 5. Further, the paper feed mechanism 10 is detachably attached to the main body 2 of the multifunction device and includes a plurality of paper feed cassettes 10a and 10b for storing paper, and a stack bypass (manual feed tray) 10c provided above the paper feed cassettes 10a and 10b. These are connected to the image forming unit 3 including the photoconductor drum 5 and the developing unit 8 by the paper transport path 11.

An image reading unit 6 is arranged on the upper part of the multifunction device main body 2, and a document transfer device 27 is attached to the upper surface of the multifunction device main body 2. The lower surface of the document transport device 27 also serves as a platen (document retainer) that presses and holds the document placed on the contact glass 25 (see FIG. 2) of the image reading unit 6. An operation unit 80 is provided on the front surface of the image reading unit 6. The operation unit 80 is provided with a liquid crystal display unit and an LED so as to indicate the state of the image forming apparatus 100, the image forming status, and the number of printed copies. In addition, the operation unit 80 has a start button instructing the user to start image formation, a stop / clear button used when stopping image formation, and when various settings of the image forming device 100 are set to the default state. There is a reset button etc. used for.

Specifically, the paper transport path 15 is bifurcated to the left and right on the downstream side of the fixing roller pair 14a, and one path (the path that branches to the right in FIG. 1) communicates with the first discharge tray 17a. It is configured as follows. Then, the other path (the path that branches to the left in FIG. 1) is bifurcated via the transfer roller pair 19, and the other path (the path that branches to the left in FIG. 1) is the second discharge tray 17b. It is configured to communicate with. On the other hand, the other path (the path that branches downward in FIG. 1) is configured to communicate with the reverse transport path 16.

Further, a control unit (CPU) 90 that controls the operation of the image forming unit 3, the image reading unit 6, the document transporting device 27, and the like is arranged in the multifunction device main body 2. The control unit 90 mainly uses a processor such as a CPU or MPU, but may be an integrated circuit such as an ASIC.

FIG. 2 is a side sectional view showing an internal structure of a document transporting device 27 that automatically transports a document to the image reading unit 6 and the image reading unit 6 according to an embodiment of the present invention, and FIG. 3 is a side sectional view showing the document transporting device 27. It is a partially enlarged view which shows the structure in the cover member 31 of. A contact glass 25 composed of an automatic reading glass 25a and a hand-held original glass 25b is arranged on the upper surface of the image reading unit 6. A transfer guide 54 for scooping up the tip of the document transferred by the document transfer device 27 is arranged between the automatic scanning glass 25a and the hand-placed document glass 25b.

The cover member 31 of the document transfer device 27 is rotatably supported in the direction of arrow AA'with respect to the frame (not shown) of the document transfer device 27 with the rotation shaft 31a on the side surface side of the device (left side in FIG. 3) as a fulcrum. Has been done. A document transport path d from the document feed tray 29 to the document ejection tray 32 is formed in the cover member 31, and a pickup roller 33, a paper feed belt 34, a separation roller 35, and a resist are formed along the document transport path d. A document transporting member including a roller pair 36, a transport roller pair 37, a discharge roller pair 43, and the like, and a back surface reading module 50 for reading an image on the back surface side of the document are provided.

Further, the back surface reading glass 56 is arranged adjacent to the back surface reading module 50. The back surface scanning glass 56 constitutes a part of the inner wall surface of the document transport path d. Further, a backside white reference plate 55 for shading correction of the backside reading module 50 is arranged at a position facing the backside reading glass 56 with the document transport path d in between. The white reference plate 55 for the back surface is attached to the inside of the cover member 31, and is arranged at a position separated from the back surface reading glass 56 and a position facing the back surface reading glass 56 as the cover member 31 opens and closes.

The document transport path d is curved so as to be inverted between the resist roller pair 36 and the automatic reading glass 25a. Further, the document transport path d is provided with a plurality of paper detection sensors (not shown) including a paper feed sensor and an ejection sensor for detecting the presence or absence or passage of the document at appropriate positions.

An open / close detection sensor 60 for detecting the opening / closing of the cover member 31 is arranged in the cover member 31. The open / close detection sensor 60 is a PI (photo interrupter) sensor including a detection unit having a light emitting unit and a light receiving unit. As shown in FIG. 3, when the cover member 31 is in the closed position, the open / close detection sensor 60 is shielded from light by a light-shielding plate 61 provided on the cover member 31 side, and the light-receiving signal level of the detection unit is in the LOW state. There is. When the cover member 31 rotates in the opening direction (upward direction) from the state of FIG. 3, the light-shielding plate 61 retracts upward from the detection unit of the open / close detection sensor 60, and the received signal level of the detection unit becomes the HIGH state. The opening / closing of the cover member 31 is detected by transmitting the light receiving signal of the opening / closing detection sensor 60 to the control unit 90 (see FIG. 1).

A surface reading module 51 is arranged inside the image reading unit 6. The surface scanning module 51 reads the original image placed on the hand-held original glass 25b while moving in the sub-scanning direction (left-right direction in FIG. 2). Further, the surface reading module 51 reads the image on the front surface side of the document transported by the document transport device 27 in a state of being stopped directly under the automatic scanning glass 25a. A surface white reference plate 57 for shading correction of the surface reading module 51 is arranged below the transport guide 54.

Next, a sheet-through type document transfer operation using the document transfer device 27 will be described. In the sheet-through method, a plurality of originals are set in the original paper feed tray 29 with the image side facing up. After that, when the copy start button of the operation unit 80 (see FIG. 1) of the image forming apparatus 100 is turned on, the lift plate (not shown) raised by the elevating mechanism (not shown) is lifted by the elevating mechanism (not shown) to the pickup roller 33 via the document. Push up. As a result, the weight of the frame (not shown) including the pickup roller 33 is applied to the lift plate, so that the upper surface of the document is pressed against the pickup roller 33 at a predetermined pressure (paper feed pressure).

Here, the pickup roller 33, the drive roller 44a, the driven roller 44b, and the paper feed belt 34 are arranged in a frame (not shown). Further, the pickup roller 33 is connected to the drive roller 44a by a gear (not shown), and when the drive roller 44a is rotated by a roller drive motor (not shown), the supply is stretched by the drive roller 44a and the driven roller 44b. The paper belt 34 is rotationally driven, and the pickup roller 33 is also rotationally driven.

The original paper set in the document paper feed tray 29 is usually fed by the pickup roller 33 to the nip portion of the paper feed belt 34 and the separation roller 35. Then, only the uppermost one of the plurality of original sheets is separated by the separation roller 35 and conveyed toward the resist roller pair 36. At that time, after the document is conveyed by a predetermined distance after the tip of the document is detected by the paper feed sensor, the rotation drive of the pickup roller 33 and the paper feed belt 34 is stopped by stopping the operation of the roller drive motor to supply the primary feed. The paper is finished. The primary paper feed stops with the tip of the original being bent in the nip portion of the resist roller pair 36.

After a predetermined time has elapsed from the end of the primary paper feeding, the secondary paper feeding is started. That is, the resist roller pair 36 is rotationally driven by the operation of the secondary paper feed drive motor (not shown). The original is conveyed toward the automatic reading glass 25a by the resist roller pair 36 and the transport roller pair 37. The document conveyed to the automatic scanning glass 25a is pressed against the automatic scanning glass 25a from above by coming into contact with the document holding member 53 arranged to face the automatic scanning glass 25a. Then, the image on the front surface side (automatic scanning glass 25a side) of the document is read by the surface scanning module 51 through the automatic scanning glass 25a.

After that, the document that has passed through the automatic scanning glass 25a is conveyed toward the transfer roller vs. 37 and the ejection roller vs. 43 via the transfer guide 54, and finally is ejected onto the document ejection tray 32 by the ejection roller pair 43. Will be done. At that time, the completion of image reading of one document is detected by detecting the passage of the trailing edge of the document by the ejection sensor. Here, the ejection sensor has a counting function for counting the number of originals each time the originals are conveyed, and if the paper feed sensor detects the subsequent originals, the second and subsequent originals are conveyed in the same manner as described above. Continue to.

When reading a double-sided document, the back surface reading module 50 provided on the upstream side of the document holding member 53 reads the image on the back surface of the document, and then the front surface scanning module 51 reads the image on the front surface of the document.

FIG. 4 is a partially enlarged view of the periphery of the back surface reading module 50 and the back surface white reference plate 55 in FIG. As shown in FIG. 3, the back surface reading module 50 is a CIS sensor (Contact Image Sensor) type reading module, and has a light source 70 and a condenser lens 71 composed of a plurality of lenses inside. A CMOS (Complementary MOS) sensor 73 as a reading means is provided, and the light emitted from the light source 70 and passed through the back surface reading glass 56 is reflected by the document (not shown). The reflected light (image light) reflected on the image surface passes through the back surface reading glass 56 again, is collected by the condenser lens 71, and is imaged on the CMOS sensor 73. The imaged image light is pixel-decomposed by the CMOS sensor 73, converted into an electric signal according to the density of each pixel, and the image is read. The CMOS sensor 73 is supported by the CCD substrate 75.

Further, although description is omitted here, the front surface reading module 51 (see FIG. 2) is also a CIS sensor type reading module, and like the back surface reading module 50, the light source 70, the condenser lens 71, and the CMOS sensor 73. It has a CCD substrate 75.

As the reading method of the surface reading module 51, it is also possible to use a CCD sensor method using a charge-coupled device called a CCD (Charge Coupled Devices). The CCD sensor method makes it easy to focus on documents with a large depth of field and depth, so even book documents and documents with irregularities can be read uniformly even if they are not in close contact with the contact glass. ) It has the advantage of high speed. On the other hand, a mirror that guides the image light to the CCD sensor is required, which has the disadvantages that the structure of the scanner unit is complicated, the size is large, and the cost is high.

By the way, in the image reading unit 6, when assembling the image forming apparatus 100 or the like, processing necessary for initial setting and adjustment of the front surface reading module 51 and the back surface reading module 50 is performed. As one of the processes, the light source 70 of the front surface reading module 51 or the back surface reading module 50 is turned on under predetermined conditions, and the light intensity data of the reflected light from the front surface white reference plate 57 or the back surface white reference plate 55 is obtained. There is a light amount adjusting process that acquires and adjusts the light amount of the light source 70.

Here, as the light source 70 mounted on the front surface reading module 51 and the back surface reading module 50, three color LEDs of R (red), G (green), and B (blue) are used, and the amount of light varies from LED to LED. be. Therefore, PWM (Pulse Width Modulation) adjustment is performed to adjust the RGB light amount balance. PWM is a modulation method in which the duty ratio of a pulse signal is changed to modulate it, and when the light source 70 is turned on under a predetermined condition, the white reference plates 55 and 57 arranged opposite to the reading modules 50 and 51 are used. The reflected light is received by the CMOS sensor 73, and the light amount is adjusted by changing the lighting time width so that the light amount converges to a predetermined value.

When performing PWM adjustment of the light source 70 of the back surface reading module 50, as shown in FIG. 3, the cover member 31 is closed and the back surface white reference plate 55 is arranged to face the back surface reading glass 56. In this state, one of the three color LEDs (for example, R) is turned on, the light emitted from the light source 70 is reflected by the white reference plate 55 for the back surface, and is condensed by the condenser lens 71, and is collected by the CMOS sensor. The output level of the CMOS sensor 73 when the light is guided to the 73 is acquired as light quantity data. Then, the lighting time width is changed so that the acquired light amount of the LED converges to a predetermined value. For example, when the amount of light is lower than a predetermined value, the lighting time width is set to double or triple. Hereinafter, the light amount data is acquired for the remaining two colors (G, B) in the same manner, and the lighting time width is set so that the light amount converges to a predetermined value.

At this time, if the PWM adjustment is performed with the cover member 31 open, the white reference plate 55 for the back surface is separated from the glass 56 for reading the back surface, so that the CMOS sensor 73 can be turned on even if the LED of the light source 70 is turned on. The reflected light from the white reference plate 55 for the back surface cannot be received, and the amount of light may be adjusted to the upper limit. Alternatively, when the cover member 31 is open, the CMOS sensor 73 receives ambient light, and the amount of light may be adjusted in the lower limit direction. Therefore, there is a possibility that a reading abnormality may occur due to an excessive amount of light or an insufficient amount of light when reading an image.

As described above, the PWM adjustment of the back surface reading module 50 requires a certain amount of time because the RGB three-color LEDs are turned on one by one and the adjustments are made sequentially. Therefore, if the cover member 31 is opened during the execution of the PWM adjustment, proper adjustment cannot be performed during the PWM adjustment, which may lead to poor adjustment of the amount of light. Further, the opening / closing detection of the cover member 31 is performed by detecting the blocking or opening of the optical path of the opening / closing detection sensor 60 provided on the document transporting device 27 side by the light-shielding plate 61 provided on the cover member 31 side. A certain detection time is required due to the approaching or separating stroke between the opening / closing detection sensor 60 and the light-shielding plate 61 accompanying the opening / closing of the 31 and the soft detection process. Therefore, a time lag occurs between the opening / closing detection timing of the cover member 31 and the start timing of the PWM adjustment, and even though the cover member 31 has begun to be opened, the PWM adjustment is executed without detecting the opening of the cover member 31. This may lead to improper adjustment of the amount of light.

Therefore, in the present embodiment, when the PWM adjustment of the back surface reading module 50 is performed, one of the three color LEDs of the light source 70 is turned on after the open / close detection sensor 60 detects that the cover member 31 is in the closed position. Then, the light amount data is acquired, and the PWM adjustment is executed based on the acquired light amount. Then, after the PWM adjustment is completed, it is re-detected that the cover member 31 is in the closed position, and when it is confirmed that the cover member 31 is in the closed position, it is determined whether or not the amount of light satisfies a predetermined condition. It is decided to shift to the PWM adjustment of the next one-color LED.

FIG. 5 is a flowchart showing a control example in the case of performing PWM adjustment of the back surface reading module 50 in the document transport device 27 of the present embodiment. The procedure for executing the PWM adjustment will be described along the steps of FIG. 5 with reference to FIGS. 1 to 4 as necessary.

When the execution of the PWM adjustment is requested at a predetermined timing such as when the image forming apparatus 100 is assembled (step S1), the control unit 90 sets the PWM adjustment order n to n = 1 (step S2). Start adjusting. Next, the control unit 90 determines whether or not the cover member 31 is in the closed position based on the detection signal transmitted from the open / close detection sensor 60 (step S3, first open / close determination process). When the cover member 31 is in the open position (No in step S3), the liquid crystal display unit of the operation unit 80 is displayed to request the closure of the cover member 31 (step S4), and the process returns to step S3.

When the cover member 31 is in the closed position (Yes in step S3), the control unit 90 turns on the first adjustment color (for example, red) of the three color LEDs of the light source 70 under a predetermined condition (step S5). ). Then, the light amount data of the light emitted from the light source 70, reflected by the white reference plate 55 for the back surface, and incident on the CMOS sensor 73 is acquired, and the PWM adjustment is performed by changing the lighting time width of the LED based on the acquired light amount. (Step S6, light intensity adjustment process).

Next, the control unit 90 determines whether or not the cover member 31 is in the closed position based on the detection signal transmitted from the open / close detection sensor 60 again after a predetermined time has elapsed from the execution of the PWM adjustment (Yes in step S7). Judgment (step S8, second open / close determination process). When the cover member 31 is in the open position (No in step S8), the cover member 31 may have been opened during the execution of the PWM adjustment. Therefore, after turning off the light source 70 (step S9), the process returns to step S4. The cover member 31 is requested to be closed, and the process returns to step S3 to confirm the closure of the cover member 31, turn on the LED of the first adjustment color, and re-execute the PWM adjustment (steps S2 to S6).

When the cover member 31 is in the closed position in step S8 (Yes in step S8), the control unit 90 determines whether or not the light amount adjustment executed in step S6 satisfies a predetermined condition (step S10, adjustment). Confirmation process). Then, when the light amount adjustment satisfies the condition (Yes in step S10), the light source 70 is turned off (step S11), and it is determined whether or not the PWM adjustment of the LEDs of all colors is completed (step S12). If there is an unadjusted LED (No in step S12), set n = n + 1 (n = 2 when the PWM adjustment of the first adjustment color is completed) (step S12), return to step S5, and then return to step S5. The PWM adjustment of the color (for example, green) of (steps S5 to S11) is executed.

If the PWM adjustment of the LEDs of all colors is completed in step S12 (Yes in step S12), the process ends. On the other hand, if the amount of light does not satisfy the condition in step S10 (No in step S10), the liquid crystal display unit of the operation unit 80 is displayed to notify the PWM adjustment abnormality of the light source 70 (step S14), and the process is completed. ..

As described above, the image reading unit 6 of the present embodiment determines the open / closed state of the cover member 31 before and after the PWM adjustment of the LEDs of each color when the PWM adjustment of the back surface reading module 50 is executed. Then, when the cover member 31 is opened before the execution of the PWM adjustment, the cover member 31 is requested to be closed without lighting the LED. Further, even if the cover member 31 is closed before the execution of the PWM adjustment, if the cover member 31 is opened after the execution of the PWM adjustment, the cover member 31 is requested to be closed without executing the adjustment confirmation process. Re-execute the PWM adjustment. Therefore, the PWM adjustment can be executed in a state where the cover member 31 is securely closed, and the adjustment failure of the light amount can be prevented.

Further, by re-determining the closed state of the cover member 31 after a lapse of a predetermined time from the execution of the PWM adjustment, even if it takes a certain time to detect the opening / closing of the cover member 31, the cover member 31 has the cover member 31 after the execution of the PWM adjustment. The open / closed state can be reliably detected. Therefore, it is possible to more effectively prevent improper adjustment of the amount of light of the light source 70.

In the control example of FIG. 5, the light source 70 is turned off (step S9) when the cover member 31 is not closed (No in step S8) after the PWM adjustment is executed (step S6), but the light source 70 is turned off. The cover member 31 may be requested to be closed while the cover member 31 is lit, and the PWM adjustment may be re-executed as it is after the closure of the cover member 31 is confirmed.

Others The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the image reading device includes an image reading unit 6 and a document transporting device 27, and is arranged in the back surface scanning module 50 and the image reading unit 6 arranged in the document transporting device 27. An image reading device having the front surface reading module 51 has been described as an example, but an image used separately from the image forming device 100 having only one reading module corresponding to the back surface reading module 50 described above. It can be applied to scanners in exactly the same way.

Further, in the above embodiment, the PWM adjustment of the back surface reading module 50 having the three color LEDs of R, G, and B as the light source 70 has been described, but the back surface reading module 50 having only the white LED as the light source 70 has been described. The PWM adjustment of the above can be performed in exactly the same procedure. In this case, since the PWM adjustment may be performed once for the white LED, steps S12 and S13 in FIG. 5 are unnecessary.

The present invention can be used for an image reading device including a reading module arranged in a document transporting device. By utilizing the present invention, it is possible to provide an image reading device capable of preventing erroneous detection due to opening and closing of a cover member when performing light amount adjustment processing of a reading module, and an image forming device including the same.

6 Image reader (image reader)
25 Contact glass 27 Document transfer device (image reader)
31 Cover member 50 Back side reading module (first reading module)
51 Surface reading module (second reading module)
55 White reference plate for the back side 57 White reference plate for the front side 60 Open / close detection sensor 61 Shading plate 70 Light source 71 Condensing lens 73 CMOS sensor 90 Control unit 100 Image forming device

Claims (8)

A document transport device that transports documents and
A first scanning module arranged in the document transporting device and capable of reading an image of a transported document transported by the document transporting device, and a first scanning module.
A control unit that controls the first reading module and
In an image reader equipped with
The document transport device is arranged on the cover member, a document transport path through which the transport document passes, a cover member capable of opening and closing a predetermined section of the document transport path, and the first cover member in a closed state. It has a white reference plate facing the reading module,
The first reading module includes a light source composed of three-color LEDs and a sensor that reads the reflected light of the light from the light source as image light.
The control unit lights each LED one color at a time with the white reference plate facing each other, acquires light intensity data by the sensor, and changes the lighting time width of each LED based on the acquired light intensity. It is possible to perform PWM adjustment to adjust the amount of light,
When the control unit executes the PWM adjustment, the control unit has a first open / close determination process for determining an open / closed state of the cover member, and
After the cover member is determined to be in the closed state by the first open / close determination process, one color of the LED is turned on to adjust the amount of light.
A second open / close determination process for redetermining the open / closed state of the cover member after executing the light amount adjusting process,
An adjustment confirmation process for determining whether or not the amount of light satisfies a predetermined condition after the cover member is determined to be in the closed state by the second open / close determination process.
Is sequentially executed for the LEDs of all colors. The image reading device according to claim 1, wherein the control unit executes the second open / close determination process after a lapse of a predetermined time after executing the light amount adjusting process. 2. The image reader of the description. When the control unit determines that the cover member is in the open state by the second open / close determination process after executing the light amount adjustment process of the nth (n; natural number) adjustment color of each of the LEDs. Any of claims 1 to 3, wherein a notification requesting closure of the cover member is given, and the process returns to the first open / close determination process to re-execute the light amount adjusting process of the nth LED. The image reading device described in the cover. Any one of claims 1 to 4, wherein the control unit notifies the light amount adjustment abnormality of the light source when it is determined by the adjustment confirmation process that the light amount does not satisfy a predetermined condition. The image reader according to the above. The image reading device according to any one of claims 1 to 5, wherein the first reading module is a close contact type image sensor. Contact glass fixed to the top of the scanner frame,
A second reading module arranged below the contact glass so as to be reciprocally movable in the sub-scanning direction,
With more
The first scanning module can read an image on the back side of the conveyed document, and can read the image.
The second scanning module can read the image on the front surface side of the hand-held document placed on the contact glass while moving in the sub-scanning direction, and is transported to the upper surface of the contact glass by the document transport device. The image reading apparatus according to any one of claims 1 to 6, wherein the image on the front surface side of the conveyed document can be read while being stopped at the reading position. An image forming apparatus equipped with the image reading device according to any one of claims 1 to 7.

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