JP2015167370A - Image reading device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading device capable of successfully removing dew condensation in the device while suppressing deterioration of a light-emitting element for image reading.SOLUTION: An image reading device 100 removes dew condensation in first mode and in second mode. When removing dew condensation in first mode, the image reading device 100 switches supply current to a light-emitting element. When removing dew condensation in second mode, the image reading device 100 fixes supply current to the light-emitting element at a predetermined value. When a lamp 11 is removing dew condensation in first mode, a storage unit 112 acquires and retains output data of a dew condensation state detecting unit 20 at predetermined time intervals. When the difference between the current output data of the dew condensation state detecting unit 20 and the most recent output data of the dew condensation state detecting unit 20 is not less than a predetermined threshold value, an LED driving unit 17 makes the current supplied to an LED11a (light-emitting element) smaller than the present current value.

Description

  The present invention relates to an image reading apparatus and an image forming apparatus.

  2. Description of the Related Art Conventionally, an image reading apparatus that reads a document and generates image data is known, and is mounted on an image forming apparatus such as a multifunction peripheral. The original image data obtained by the reading of the image reading apparatus is output to the print output unit of the image forming apparatus, and the print output unit prints the original image on a sheet and outputs it.

  Here, depending on the installation environment of the image reading apparatus, condensation may occur in the image reading apparatus. For example, condensation adheres to a lens or a mirror in the image reading apparatus. When dew condensation occurs in the image reading apparatus, the image indicated by the image data obtained by reading becomes blacker than the actual image. In order to eliminate such inconvenience, conventionally, there has been proposed a technique for removing condensation in the image reading apparatus by using heat generated from a light source for generating light to be irradiated on a reading target (for example, , See Patent Document 1).

JP 11-127304 A

  In Patent Document 1, when condensation occurs in the image reading apparatus, the condensation removal is started by turning on a light source for generating light to be irradiated on the reading target. If the condensation in the reader is not removed, the light source is kept on at the same voltage as the drive voltage at the start of condensation removal (dew condensation removal is continued). Here, in the case of removing condensation in the image reading apparatus using heat generated by the light source for generating light to be irradiated on the reading target, it takes about several hours to remove the condensation in the image reading apparatus. Cost. That is, since the same voltage as the drive voltage at the start of condensation removal is continuously applied to the light source for a long time, the deterioration of the light source is accelerated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to satisfactorily remove condensation in the apparatus while suppressing deterioration of a light-emitting element for image reading.

  In order to achieve the above object, an image reading apparatus of the present invention includes a light emitting element that generates light to be irradiated on a reading target, and removes condensation in the image reading apparatus using heat generated when the light emitting element is turned on. A lamp that performs lighting, an element driving unit that drives the light emitting element to light, a dew state detector that outputs data indicating a dew state in the image reading device, and a storage unit that stores output data of the dew state detector Prepare. When the lamp is performing condensation removal, the storage unit acquires and holds the output data of the condensation state detection unit at a predetermined time interval, and the element driving unit outputs the output of the current condensation state detection unit. If the difference between the data and the output data of the most recent dew condensation state detection unit held in the storage unit is equal to or greater than a predetermined threshold, the current supplied to the light emitting element is made smaller than the current value, When the difference between the output data of the dew condensation state detection unit and the output data of the latest dew condensation state detection unit is below the threshold value, the current supplied to the light emitting element is made larger than the current value.

  Here, since the output data of the dew condensation state detection unit indicates the dew condensation state in the image reading device, the output data of the dew condensation state detection unit changes over time when dew condensation is removed in the image reading device. To do. For this reason, when the dew condensation in the image reading apparatus is well removed, the rate of change in the output data of the dew condensation state detection unit is larger than in the case where the dew condensation in the image reading apparatus is not removed well. Become.

  Therefore, in the configuration of the present invention, when the lamp is performing condensation removal, the storage unit acquires and holds the output data of the condensation state detection unit at a predetermined time interval. When the difference between the current output data of the dew condensation state detection unit and the output data of the latest dew condensation state detection unit held in the storage unit is equal to or greater than a predetermined threshold value, the element driving unit The current supplied to is made smaller than the current value. That is, when the condensation removal in the image reading apparatus is proceeding satisfactorily, the current supplied to the light emitting element is reduced to suppress the voltage from being applied to the light emitting element more than necessary.

  On the other hand, when the difference between the current output data of the dew condensation state detection unit and the output data of the latest dew condensation state detection unit held in the storage unit is below the threshold value, the element driving unit supplies the light emitting element. Current to be larger than the current value. That is, when the condensation removal in the image reading apparatus has not progressed well, the supply current to the light emitting element is increased. As a result, heat generation when the light emitting element is driven to light increases, and condensation removal in the image reading apparatus is promoted.

  As a result, it is possible to satisfactorily remove condensation in the image reading apparatus while suppressing deterioration of the light emitting element for image reading.

  As described above, according to the present invention, it is possible to satisfactorily remove condensation in the image reading apparatus while suppressing deterioration of the light emitting element for image reading.

1 is a schematic diagram of an image forming apparatus including an image reading apparatus according to an embodiment of the present invention. Detailed view of the image reading apparatus shown in FIG. 1 is a plan view of the image reading apparatus shown in FIG. 1 is a block diagram for explaining a hardware configuration of an image forming apparatus including the image reading apparatus shown in FIG. 1 is a block diagram for explaining a hardware configuration of the image reading apparatus shown in FIG. The figure for demonstrating an example of the screen displayed when accepting the setting of the dew condensation removal mode in the image reading apparatus shown in FIG. The flowchart for demonstrating the condensation removal operation | movement performed in the image reading apparatus shown in FIG. The flowchart for demonstrating the condensation removal operation | movement performed in the image reading apparatus shown in FIG.

(Overall configuration of image forming apparatus provided with image reading apparatus)
First, an overall configuration of an image forming apparatus provided with an image reading apparatus will be described by taking as an example a complex machine capable of executing a plurality of types of jobs such as copying, scanning, and faxing.

  As shown in FIG. 1, in the present embodiment, the image reading apparatus 100 is disposed above the image forming apparatus 200. The image reading apparatus 100 includes an image reading unit 1 and a document conveying unit 2. The image reading unit 1 reads the document D and generates image data. The document transport unit 2 transports the document D to the image reading unit 1 and presses the document D read by the image reading unit 1.

  Further, the image forming apparatus 200 includes a print output unit 7 including a paper feed unit 3, a paper transport unit 4, an image forming unit 5, and a fixing unit 6. Then, the print output unit 7 prints and outputs the image on the paper P based on the image data of the image to be printed.

  Specifically, the paper feed unit 3 stores the paper P and supplies the stored paper P to the paper transport unit 4. Therefore, the paper feed unit 3 is provided with a pickup roller 31 that pulls out the stored paper P one by one and supplies it to the paper transport unit 4. The paper transport unit 4 transports the paper P supplied from the paper feed unit 3 in the order of the image forming unit 5 and the fixing unit 6. A plurality of transport roller pairs 41 perform transport of the paper P in the paper transport unit 4. One roller pair of the plurality of transport roller pairs 41 is a registration roller pair 42, and the registration roller pair 42 waits for the paper P in front of the image forming unit 5 and matches the timing with the image forming unit 5. To send. The paper P transported by the paper transport unit 4 is finally guided to the discharge tray 43.

  The image forming unit 5 forms a toner image based on the image data of the image to be printed, and transfers the toner image onto the paper P. The image forming unit 5 includes a photosensitive drum 51, a charging device 52, an exposure device 53, a developing device 54, a transfer roller 55, and a cleaning device 56.

  As a toner image forming process and a toner image transfer process, first, the photosensitive drum 51 is rotationally driven, and the surface of the photosensitive drum 51 is charged to a predetermined potential by the charging device 52. The exposure device 53 includes a light emitting element (not shown) that generates exposure light, and scans and exposes the surface of the photosensitive drum 51 while turning on and off the light emitting element based on image data. . As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 51. Subsequently, the developing device 54 supplies toner to the electrostatic latent image formed on the surface of the photosensitive drum 51 and develops it.

  The transfer roller 55 is in pressure contact with the surface of the photosensitive drum 51. Then, the registration roller pair 42 measures the timing and causes the paper P to enter between the transfer roller 55 and the photosensitive drum 51. At this time, a transfer voltage is applied to the transfer roller 55. As a result, the toner image on the surface of the photosensitive drum 51 is transferred to the paper P. When the toner image transfer process is finished, the cleaning device 56 removes the toner remaining on the surface of the photosensitive drum 51.

  The fixing unit 6 heats and pressurizes the toner image transferred to the paper P and fixes it. The fixing unit 6 includes a fixing roller 61 having a built-in heat source and a pressure roller 62 that is pressed against the fixing roller 61. The paper P on which the toner image is transferred is heated and pressed by passing between the fixing roller 61 and the pressure roller 62. As a result, the toner image is fixed on the paper P and printing is completed. The printed paper P is sent to the discharge tray 43 by the transport roller pair 41.

  In addition, the image reading apparatus 100 (image forming apparatus 200) includes an operation panel 8. The operation panel 8 is disposed on the front side of the image reading apparatus 100 and includes a liquid crystal display unit 81 whose display surface is covered with a touch panel. The liquid crystal display unit 81 displays setting keys (soft keys) and messages for receiving various settings. Further, the operation panel 8 is provided with hard keys such as a numeric keypad 82 for accepting numerical input and a start key 83 for accepting job execution instructions. For example, the image reading unit 1 starts reading the document D when the start key 83 is pressed.

(Configuration of image reading apparatus)
Next, an example of the configuration of the image reading apparatus 100 (the image reading unit 1 and the document conveying unit 2) according to the present embodiment will be described.

  As shown in FIG. 2, the document transport unit 2 pulls out the document D set on the document set tray 21 and discharges it to the document discharge tray 23 through the document transport path 22. Note that when a plurality of documents D are set on the document set tray 21, the document transport unit 2 automatically and continuously pulls out the documents D one by one from the plurality of documents D.

  A document feed roller 24, a document transport roller pair 25, and a document discharge roller pair 26 are provided in the document transport path 22 in order from the upstream side in the document transport direction. Then, the document D set on the document setting tray 21 is pulled out by the document supply roller 24 and conveyed by the document conveyance roller pair 25. Thereafter, the document D is discharged to the document discharge tray 23 by the document discharge roller pair 26.

  The image reading unit 1 has a box-shaped housing. A conveyance reading contact glass 20a is disposed at one end of the upper surface of the casing, and a placement reading contact glass 20b is disposed at the center of the upper surface of the casing.

  Further, in the space on the back side of the conveyance reading contact glass 20a and the placement reading contact glass 20b (on the side opposite to the surface in contact with the document D), the lamp 11, the first mirror 12, the second mirror 13, and the third A mirror 14, a lens 15, an image sensor 16, and the like are provided.

  The lamp 11 includes a plurality of LEDs 11 a (corresponding to the “light emitting element” of the present invention) that generate light to be applied to the document D to be read. Although not shown, the plurality of LEDs 11a are arranged in a line in the main scanning direction (direction perpendicular to the paper surface of FIG. 2) which is the reading line direction.

  When reading the document D, the lamp 11 irradiates light toward the transport reading contact glass 20a (or the placement reading contact glass 20b). That is, when the document D is conveyed on the surface of the conveyance reading contact glass 20a, the light transmitted through the conveyance reading contact glass 20a irradiates the document D, and on the surface of the placement reading contact glass 20b. When the document D is placed on the document D, the light transmitted through the placement reading contact glass 20b irradiates the document D. The reflected light reflected by the document D is reflected in the order of the first mirror 12, the second mirror 13, and the third mirror 14 and guided to the lens 15. The lens 15 collects the reflected light.

  The image sensor 16 receives the light reflected by the document D (the light collected by the lens 15), thereby reading the document D in units of lines. The image sensor 16 is composed of a CCD having a plurality of photoelectric conversion elements arranged in a line in the main scanning direction. When the reflected light is received, the image sensor 16 performs photoelectric conversion for each pixel in units of lines and accumulates charges. The corresponding analog signal is output. That is, the output value of each pixel of the image sensor 16 varies according to the amount of reflected light.

  Further, a first moving frame 111, a second moving frame 112, a wire 113, and a winding drum 114 are provided on the back side of the conveyance reading contact glass 20a and the placement reading contact glass 20b.

  The first moving frame 111 supports the lamp 11 and the first mirror 12. The second moving frame 112 supports the second mirror 13 and the third mirror 14. One end of a wire 113 is connected to the first moving frame 111 and the second moving frame 112. The other end of the wire 113 is connected to the winding drum 114. Therefore, when the winding drum 114 rotates, the first moving frame 111 and the second moving frame 112 move in the sub-scanning direction (direction orthogonal to the main scanning direction). That is, the lamp 11, the first mirror 12, the second mirror 13, and the third mirror 14 move in the sub scanning direction.

  When reading the document D conveyed on the surface of the conveyance reading contact glass 20a, the take-up drum 114 rotates, and the first moving frame 111 and the second moving frame 112 are formed on the conveyance reading contact glass 20a. Moves down and stops still. Thereafter, the document transport unit 2 transports the document D onto the surface of the transport reading contact glass 20a. At this time, the lamp 11 irradiates light to the document D passing over the surface of the conveyance reading contact glass 20a, and the image sensor 16 continuously performs photoelectric conversion of the reflected light reflected by the document D. As a result, the document D is read line by line.

  On the other hand, when reading the document D placed on the placement reading contact glass 20b, the take-up drum 114 rotates and the first moving frame 111 and the second moving frame 112 move in the sub-scanning direction (viewed from the front). Move from left to right). Then, while the first moving frame 111 and the second moving frame 112 are moving in the sub-scanning direction, the lamp 11 irradiates the document D placed on the placement reading contact glass 20b. Then, the image sensor 16 continuously performs photoelectric conversion of the reflected light reflected by the document D. As a result, the document D is read line by line.

  The document conveying unit 2 is attached to the image reading unit 1 by rotating (opening and closing) the document conveying unit 2 with respect to the image reading unit 1 with a rotation shaft (not shown) provided on the back side as a fulcrum. ). When the document conveying unit 2 is closed (the state shown in FIG. 2), the image reading unit 1 and the document conveying unit 2 are overlapped, and the conveyance reading contact glass 20a and the placement reading contact glass 20b are the document conveying unit. 2 covered.

  A white reference plate 27 for acquiring white reference data used for shading correction is provided on a predetermined portion of the document conveying unit 2 that faces the surface of the conveyance reading contact glass 20a when the document conveying unit 2 is closed. Is provided. That is, in a state in which the document conveying unit 2 is closed, the white reference plate 27 is disposed to face the surface of the conveyance reading contact glass 20a. For this reason, when the document D is not conveyed on the surface of the conveyance reading contact glass 20a (when there is no document D on the surface of the conveyance reading contact glass 20a), it is below the back surface of the conveyance reading contact glass 20a. When the lamp 11 is turned on, the light from the lamp 11 is reflected by the white reference plate 27.

  As shown in FIG. 3, the white reference plate 27 is formed in a substantially rectangular shape in plan view, and has an outer dimension smaller than that of the conveyance reading contact glass 20a. In FIG. 3, the white reference plate 27 is hatched to make the drawing easy to see.

(Hardware configuration of image forming apparatus provided with image reading apparatus)
Next, an example of a hardware configuration of the image forming apparatus 200 including the image reading apparatus 100 will be described.

  As shown in FIG. 4, the image forming apparatus 200 includes a main body control unit 210. The main body control unit 210 includes a CPU 211 that is a central processing unit, a storage unit 212, an image processing unit 213, and the like. The storage unit 212 includes a ROM, a RAM, an HDD, and the like. For example, various programs and data are stored in the ROM and expanded in the RAM. The image processing unit 213 includes an ASIC dedicated to image processing, a memory, and the like, and performs various types of image processing such as enlargement / reduction, density conversion, and data format conversion on the image data.

  Further, the main body control unit 210 is connected to the print output unit 7 (the paper feeding unit 3, the paper transport unit 4, the image forming unit 5 and the fixing unit 6) and the operation panel 8. Then, the main body control unit 210 performs control and calculation of each unit based on various programs and data stored in the storage unit 212. Further, the main body control unit 210 is connected to the image reading apparatus 100 (the image reading unit 1 and the document conveying unit 2), and also controls the image reading unit 1 and the document conveying unit 2.

(Hardware configuration of image reading apparatus)
Next, an example of a hardware configuration of the image reading apparatus 100 (the image reading unit 1 and the document conveying unit 2) will be described.

  As shown in FIG. 5, the image reading apparatus 100 includes a reading control unit 110 that controls the operation of the image reading unit 1 and a document conveyance control unit 120 that controls the operation of the document conveyance unit 2.

  The document conveyance control unit 120 is connected to the main body control unit 210. The document conveyance control unit 120 includes a CPU 121 and a storage unit 122 (ROM or RAM). For example, a program and data relating to conveyance of the document D are stored in the ROM, and the program and data are expanded in the RAM. The document conveyance control unit 120 is connected to the document conveyance motor M2. The document conveyance control unit 120 receives an instruction from the main body control unit 210 and controls the document D conveyance operation. That is, the document conveyance control unit 120 controls the driving of the document conveyance motor M2, and appropriately operates the document supply roller 24, the document conveyance roller pair 25, and the document discharge roller pair 26.

  The reading control unit 110 is connected to the main body control unit 210. The reading control unit 110 includes a CPU 111 and a storage unit 112 (ROM or RAM). For example, a program and data relating to reading of the document D are stored in the ROM, and the program and data are expanded in the RAM. The reading control unit 110 receives an instruction from the main body control unit 210 and controls the reading operation of the document D.

  Specifically, the reading control unit 110 is connected to the winding motor M1, and appropriately rotates the winding drum M1. That is, the reading control unit 110 controls the irradiation position (reading position) of the lamp 11. The reading control unit 110 is connected to the image sensor 16, the LED driving unit 17 (corresponding to the “element driving unit” of the present invention), the A / D conversion unit 18, and the image memory 19, and also controls these units.

  The LED drive unit 17 supplies current to the lamp 11 (LED 11a) to drive the LED 11a to light. The A / D converter 18 converts the analog signal output from the image sensor 16 into digital image data (density data) and outputs the digital image data. When the white reference plate 27 is read, the A / D converter 18 outputs white reference data. The image memory 19 accumulates the image data (white reference data) output from the A / D conversion unit 18 and transfers it to the main body control unit 210. Alternatively, the storage unit 112 acquires and holds white reference data.

  Receiving the image data of the document D obtained by reading the document reading unit 1, the main body control unit 210 performs various image processing on the image data of the document D, and exposes the image data for exposure (light emission of the exposure device 53). Image data for turning on and off the element). Then, the main body control unit 210 outputs the image data for exposure to the print output unit 7.

(Condensation removal operation)
In this embodiment, when dew condensation occurs inside the image reading apparatus 100 (specifically, inside the housing of the image reading unit 1), dew condensation removal using heat generated when the LED 11a constituting the lamp 11 is driven to turn on. It can be performed. For example, in the configuration of the present embodiment, when condensation occurs in the housing of the image reading unit 1, the condensation in the housing of the image reading unit 1 is removed by continuously lighting the LED 11 a for 1 to 2 hours. can do.

  Specifically, the reading control unit 110 first obtains data indicating the dew condensation state in the housing of the image reading unit 1 at a predetermined time such as when the power is turned on or when the job is finished. It is determined whether or not condensation has occurred in the housing of the image reading unit 1. When the reading control unit 110 determines that condensation has occurred in the housing of the image reading unit 1, the reading control unit 110 causes the condensation in the housing of the image reading unit 1 to be removed.

  Here, in an environment where condensation occurs in the housing of the image reading unit 1, condensation adheres to the white reference plate 27. In this way, when dew adheres to the white reference plate 27, the white reference data (output data of the A / D converter 18) determined by the output of the image sensor 16 when the white reference plate 27 is read is the white reference plate 27. Compared to the white reference data in the case where no dew condensation is attached, the value approaches black. That is, there is a difference between the white reference data when condensation is attached to the white reference plate 27 and the white reference data when condensation is not attached to the white reference plate 27. Therefore, the reading control unit 110 acquires the white reference data as data indicating the dew condensation state in the housing of the image reading unit 1 when the power is turned on and when the job is finished, and based on the white reference data, the reading control unit 110 It is determined whether or not condensation has occurred in the housing. In this configuration, the image sensor 16 and the A / D conversion unit 18 correspond to the “condensation state detection unit” of the present invention. Hereinafter, the image sensor 16 and the A / D conversion unit 18 may be referred to as a dew condensation state detection unit 20.

  For example, the reading control unit 110 performs reading at a plurality of locations on the white reference plate 27 and acquires white reference data (output data of the dew condensation state detection unit 20) at a plurality of locations on the white reference plate 27. Thereafter, the reading control unit 110 determines whether at least one of the current white reference data is out of a preset range (a range set based on the white reference data when no condensation occurs). to decide. In other words, it is determined whether or not the current white reference data is the same as or substantially the same as the white reference data when no condensation occurs. For example, it is determined whether or not the average value of the image values for one line is out of the set range. Alternatively, it is determined whether or not the pixel values out of the setting range among the pixel values for one line exceed a predetermined number. If the current white reference data is out of the set range (if different from the white reference data when no condensation occurs), the reading control unit 110 determines that condensation has occurred in the housing of the image reading unit 1. to decide. On the other hand, if all the white reference data among the current white reference data is within the set range (if the white reference data is the same or substantially the same as the white reference data when no condensation occurs), the reading control unit 110 Then, it is determined that no condensation has occurred in the housing of the image reading unit 1.

  If the reading control unit 110 determines that condensation has occurred in the housing of the image reading unit 1, the reading control unit 110 turns on the LED 11a constituting the lamp 11 (shifts to the condensation removal mode). Thereby, dew condensation generated in the housing of the image reading unit 1 is removed by heat generated when the LED 11a is turned on. Note that if an instruction to execute a job involving a scan is received during the condensation removal mode, priority is given to the execution of the job that has received the execution instruction.

  However, if condensation is removed in the housing of the image reading unit 1 using heat generated when the LED 11a is turned on, a voltage is applied to the LED 11a for 1 to 2 hours each time the condensation removal mode is entered. It becomes a state. For this reason, there arises a disadvantage that the deterioration of the LED 11a is accelerated.

  Therefore, in the present embodiment, when the lamp 11 is performing condensation removal, the current supplied to the LED 11a is adjusted according to the condensation state in the housing of the image reading unit 1 (the voltage applied to the LED 11a is adjusted). . In other words, when the condensation removal within the housing of the image reading unit 1 is proceeding satisfactorily, the current supplied to the LED 11a is lowered (the voltage applied to the LED 11a is lowered).

  In order to recognize the dew condensation state in the housing of the image reading unit 1 when the lamp 11 is performing dew condensation removal, the reading control unit 110 determines the white reference determined by the output of the image sensor 16 when the white reference plate 27 is read. Data (output data of the dew condensation state detection unit 20) is acquired and held in the storage unit 112 at predetermined time intervals. Then, the current white reference data is compared with the latest white reference data held in the storage unit 112 (for example, the average value of image values for one line is compared). Here, the small difference between the current white reference data and the most recent white reference data means that the current state of condensation on the white reference plate 27 has hardly changed compared to the most recent state. Yes, it means that condensation removal has not progressed well. On the other hand, the fact that the difference between the current white reference data and the latest white reference data is large means that the condensation on the white reference plate 27 has decreased, and that the condensation removal has progressed well. That is.

  For this reason, the reading control unit 110 determines that the condensation removal is proceeding satisfactorily when the difference between the current white reference data and the latest white reference data is equal to or greater than a predetermined threshold. In this case, the LED driving unit 17 makes the current (voltage applied to the LED 11a) supplied to the LED 11a smaller than the current current (voltage). On the other hand, when the difference between the current white reference data and the latest white reference data is below the threshold, the reading control unit 110 determines that the condensation removal has not progressed well. In this case, the LED drive part 17 makes the electric current (voltage concerning LED11a) supplied to LED11a larger than the current electric current (voltage).

  The LED driving unit 17 decreases the supply current to the LED 11a by a predetermined value every time the difference between the current white reference data and the latest white reference data is equal to or greater than a threshold value. The LED drive unit 17 increases the supply current to the LED 11a by a predetermined value every time the difference between the current white reference data and the latest white reference data falls below the threshold value. For example, the predetermined value is set to a value that does not deviate from the allowable current range even if the current is increased or decreased over a plurality of stages from the LED drive current value at the start of condensation removal (for example, the LED drive current value at the time of normal reading). The In addition, when the supply current value to the LED 11a exceeds the upper limit value or the lower limit value of the allowable current range, the LED drive unit 17 holds the supply current to the LED 11a without changing.

  By the way, depending on the user, there is a case where it is desired to quickly end the condensation removal in the housing of the image reading unit 1. For this reason, in this embodiment, it is configured to accept whether the condensation removal in the housing of the image reading unit 1 is performed in the first mode or the second mode. The first mode is a mode (recommended mode) for switching the supply current to the LED 11a based on the difference between the current white reference data and the latest white reference data when the lamp 11 is performing condensation removal. On the other hand, in the second mode, when the lamp 11 is performing condensation removal, the supply current to the LED 11a is not switched and the supply current to the LED 11a is set to a relatively large value (the upper limit value of the allowable current range). Or a value in the vicinity thereof (high speed mode).

  The operation panel 8 accepts the setting of the condensation removal mode. When the operation panel 8 accepts the setting of the condensation removal mode, as shown in FIG. 6, the operation panel 8 receives a soft key K1 for accepting an instruction to perform condensation removal in the recommended mode (first mode), and the high-speed mode (second mode). ) Displays a soft key K2 for receiving an instruction to remove condensation. When one of the soft keys K1 and K2 is pressed and the “OK” key K3 is subsequently pressed, the operation panel 8 corresponds to the pressed soft key of the soft keys K1 and K2. Accept to set to mode.

  Then, if the operation panel 8 accepts that the condensation removal is performed in the first mode, the LED drive unit 17 has the current white reference data and the latest white reference data when the lamp 11 is performing the condensation removal. Based on the difference between the two, the current supplied to the LED 11a is switched, and if the operation panel 8 accepts that condensation is removed in the second mode, the current supplied to the LED 11a is fixed to a predetermined value.

  Hereinafter, the flow of the condensation removal operation will be described with reference to the flowcharts shown in FIGS.

  First, at the start of the flowcharts of FIGS. 7 and 8, the dew condensation removal mode is a mode (recommended mode) in which the supply current to the LED 11a is switched based on the difference between the current white reference data and the latest white reference data. Assume that one mode is selected. The flowcharts of FIGS. 7 and 8 start when predetermined times such as power-on and job end are reached.

  In step S <b> 1, the reading control unit 110 acquires the current white reference data (data indicating the dew condensation state in the housing of the image reading unit 1). That is, the reading control unit 110 causes the white reference plate 27 to be read.

  In step S2, the reading control unit 110 determines whether or not the current white reference data is within a preset range (the current white reference data is the same as or substantially the same as the white reference data when no condensation occurs). Whether or not). As a result of the determination, if the current white reference data is within the set range, the condensation removal by the lamp 11 is not started and the process is ended as it is. On the other hand, if the current white reference data is not within the set range, the process proceeds to step S3.

  In step S3, the reading control unit 110 instructs the LED driving unit 17 to start the condensation removal by the lamp 11. That is, the LED driving unit 17 supplies current to the LED 11a and drives the LED 11a to light. At this time, for example, the LED 11a is driven to light at the same current value as that at the time of reading. In step S <b> 4, the reading control unit 110 acquires and holds the current white reference data in the storage unit 112. At this time, the white reference data acquired in step S1 is stored in the storage unit 112.

  In step S5, the reading control unit 110 determines whether or not a predetermined time has elapsed (whether or not an elapsed time from the time when the white reference data is acquired has reached a predetermined time). As a result of the determination, if a predetermined time has elapsed, the process proceeds to step S6, and if the predetermined time has not elapsed, the determination in step S5 is repeated.

  In step S6, the reading control unit 110 reads the white reference plate 27 to acquire the current white reference data (white reference data when a predetermined time has elapsed).

  In step S7, the reading control unit 110 determines whether or not the current white reference data is within a preset range (the current white reference data is the same as or substantially the same as the white reference data when no condensation occurs). Whether or not). If it is determined that the current white reference data is not within the set range, the process proceeds to step S8.

  In step S8, the reading control unit 110 determines whether or not the difference between the current white reference data and the most recent white reference data held in the storage unit 112 is equal to or greater than a predetermined threshold value. As a result of the determination, if the difference between the current white reference data and the latest white reference data is greater than or equal to the threshold, the process proceeds to step S9. In step S9, the reading control unit 110 instructs the LED driving unit 17 to decrease the current supplied to the LED 11a by a predetermined value.

  On the other hand, if the difference between the current white reference data and the latest white reference data is less than the threshold value in step S8, the process proceeds to step S10. In step S10, the reading control unit 110 instructs the LED driving unit 17 to increase the current supplied to the LED 11a by a predetermined value.

  After step S9 or after step S10, the process proceeds to step S4. In step S4, the reading control unit 110 causes the storage unit 112 to hold the current white reference data. At this time, the white reference data acquired in step S6 is held in the storage unit 112 (the white reference data stored in the storage unit 112 is rewritten). And operation | movement of step S5-step S7 is performed.

  If it is determined in step S7 that the current white reference data is within the set range, the process proceeds to step S11. In step S11, the reading control unit 110 stops the condensation removal by the lamp 11. That is, the LED drive unit 17 stops supplying current to the LED 11a. In step S <b> 12, the reading control unit 110 erases the white reference data stored in the storage unit 112.

  As described above, the image reading apparatus 100 of the present embodiment includes the LED 11a (light emitting element) that generates light to be irradiated to the reading target, and uses the heat generated when the LED 11a is driven to turn on. , A LED 11 that performs dew condensation removal, an LED drive unit 17 (element drive unit) that drives the LED 11a to light, and a dew state detection unit 20 that outputs data indicating the dew condensation state inside the image reading apparatus 100 (image sensor 16 and A / D conversion unit 18) and a storage unit 112 that stores output data of the dew condensation state detection unit 20. And when the lamp | ramp 11 is performing dew condensation removal, the memory | storage part 112 acquires and hold | maintains the output data of the dew condensation state detection part 20 at a predetermined time interval, and the LED drive part 17 is the present dew condensation state. If the difference between the output data of the detection unit 20 and the output data of the most recent dew condensation state detection unit 20 held in the storage unit 112 is equal to or greater than a predetermined threshold value, the current supplied to the LED 11a is determined as the current current value. If the difference between the current output data of the dew condensation state detection unit 20 and the output data of the latest dew condensation state detection unit 20 is less than the threshold value, the current supplied to the LED 11a is less than the current current value. Also make it bigger.

  Here, since the output data of the dew condensation state detection unit 20 indicates the dew condensation state inside the image reading apparatus 100, when the dew condensation is removed inside the image reading apparatus 100, the output of the dew condensation state detection unit 20 is output. Data changes over time. For this reason, when the dew condensation inside the image reading apparatus 100 is well removed, the output data of the dew condensation state detection unit 20 is compared with the case where the dew condensation inside the image reading apparatus 100 is not well removed. The rate of change increases.

  Therefore, in the present embodiment, when the lamp 11 is performing condensation removal, the storage unit 112 acquires and holds the output data of the condensation state detection unit 20 at a predetermined time interval. When the difference between the output data of the current condensation state detection unit 20 and the output data of the latest condensation state detection unit 20 held in the storage unit 112 is equal to or greater than a predetermined threshold, the LED drive unit 17 Makes the current supplied to the LED 11a smaller than the current value. That is, when the dew condensation inside the image reading apparatus 100 is proceeding satisfactorily, the supply current to the LED 11a is reduced to suppress the voltage from being applied to the LED 11a more than necessary.

  On the other hand, when the difference between the current output data of the dew condensation state detection unit 20 and the output data of the latest dew condensation state detection unit 20 held in the storage unit 112 is below the threshold, the LED drive unit 17 The current supplied to the LED 11a is made larger than the current value. That is, when the condensation removal inside the image reading apparatus 100 is not progressing well, the supply current to the LED 11a is increased. As a result, heat generation when the LED 11a is driven to light increases, and condensation removal inside the image reading apparatus 100 is promoted.

  As a result, it is possible to satisfactorily remove condensation inside the image reading apparatus 100 while suppressing deterioration of the image reading LED 11a.

  Further, in the present embodiment, as described above, the LED driving unit 17 causes the difference between the current output data of the dew condensation state detection unit 20 and the output data of the latest dew condensation state detection unit 20 to be equal to or greater than a threshold value. The current supplied to the LED 11a is decreased by a predetermined value. As a result, if the dew condensation inside the image reading apparatus 100 is proceeding well, the supply current to the LED 11a decreases each time a predetermined time elapses (the voltage applied to the LED 11a decreases). Therefore, deterioration of LED11a can be suppressed more.

  In the present embodiment, as described above, the LED driving unit 17 causes the LED 11a to be output each time the difference between the current output data of the dew condensation state detection unit 20 and the output data of the latest dew condensation state detection unit 20 falls below the threshold value. The supply current to is increased by a predetermined value. Thereby, the condensation removal inside the image reading apparatus 100 is further promoted.

  In the present embodiment, as described above, the operation panel 8 (receiving unit) that receives whether the dew condensation inside the image reading apparatus 100 is performed in the first mode or the second mode is provided, and the LED driving unit 17 is provided. If the operation panel 8 accepts that condensation is removed in the first mode, when the lamp 11 is removing condensation, the output data of the current condensation state detection unit 20 and the latest condensation state detection unit The supply current to the LED 11a is switched based on the difference with the output data of 20, and if the operation panel 8 accepts that the condensation is removed in the second mode, the supply current to the LED 11a is fixed to a predetermined value. . For example, if the operation panel 8 accepts that the condensation removal is performed in the second mode, the LED drive unit 17 sets the supply current to the LED 11a to a value larger than that during normal reading (the upper limit value of the allowable current range or its upper limit value). (Near value). Therefore, in the case where condensation is removed in the second mode, the condensation removal inside the image reading apparatus 100 is completed more quickly than in the case where condensation is removed in the first mode. Therefore, by making it possible to select whether to perform condensation removal in the first mode or to perform condensation removal in the second mode, the convenience of the user who wants to end condensation removal inside the image reading apparatus 100 quickly is improved. .

  In the present embodiment, as described above, the white reference plate 27 for obtaining the white reference data used for the shading correction is provided, and the dew condensation state detection unit 20 includes the image sensor 16 for reading the white reference plate 27. In addition, white reference data determined by the output of the image sensor 16 when the white reference plate 27 is read is output as data indicating the dew condensation state inside the image reading apparatus 100. Here, in an environment where dew condensation occurs inside the image reading apparatus 100, dew condensation adheres to the white reference plate 27. As described above, the white reference data when condensation is attached to the white reference plate 27 is closer to a value indicating black than the white reference data when condensation is not attached to the white reference plate 27. That is, there is a difference between the white reference data when condensation is attached to the white reference plate 27 and the white reference data when condensation is not attached to the white reference plate 27. Thereby, if the white reference data is used as data indicating the dew condensation state inside the image reading apparatus 100, the dew condensation state inside the image reading apparatus 100 can be easily recognized.

  It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is shown not by the description of the above-described embodiment but by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

  For example, in the above embodiment, white reference data is used as data indicating the dew condensation state. However, the present invention is not limited to this, and a humidity detection unit is provided in the image reading apparatus, and dew condensation is performed based on output data of the humidity detection unit. The state may be identified. In this case, the humidity detector corresponds to the “condensation state detector” of the present invention.

8 Operation panel (reception part)
11 lamp 11a LED (light emitting element)
16 Image sensor 17 LED drive unit (element drive unit)
20 Condensation State Detection Unit 27 White Reference Plate 100 Image Reading Device 112 Storage Unit 200 Image Forming Device

Claims (5)

A lamp that includes a light-emitting element that generates light to irradiate a reading target, and that performs condensation removal in the image reading apparatus using heat generated when the light-emitting element is turned on;
An element driving unit for driving the light emitting element to light;
A dew state detector that outputs data indicating the dew state in the image reader;
A storage unit for storing output data of the dew condensation state detection unit;
An accepting unit for accepting whether or not condensation removal in the image reading apparatus is performed in the first mode or the second mode;
With
If the receiving unit accepts that the element driving unit performs condensation removal in the first mode, the lamp is performing condensation removal.
The storage unit acquires and holds the output data of the dew condensation state detection unit at a predetermined time interval,
When the difference between the current output data of the dew condensation state detection unit and the latest output data of the dew condensation state detection unit held in the storage unit is equal to or greater than a predetermined threshold, When the current supplied to the light emitting element is made smaller than the current current value, and the difference between the current output data of the dew condensation state detection unit and the output data of the latest dew condensation state detection unit is below the threshold value The current supplied to the light emitting element is larger than the current value,
An image reading apparatus characterized in that if the accepting unit accepts that condensation is removed in the second mode, the supply current to the light emitting element is fixed to a predetermined value.   The element driving unit determines a supply current to the light emitting element every time the difference between the output data of the current condensation state detection unit and the output data of the latest condensation state detection unit is equal to or greater than the threshold value. The image reading apparatus according to claim 1, wherein the image reading apparatus is decreased by a predetermined value.   The element driving unit has a predetermined supply current to the light emitting element each time a difference between output data of the current dew state detection unit and output data of the latest dew state detection unit falls below the threshold value. The image reading apparatus according to claim 1, wherein the image reading apparatus is increased by a predetermined value. A white reference plate is provided for acquiring white reference data used for shading correction.
The dew condensation state detection unit includes an image sensor for reading the white reference plate, and the white reference determined by the output of the image sensor when the white reference plate is read as data indicating the dew condensation state in the image reading apparatus. The image reading apparatus according to claim 1, wherein the image reading apparatus outputs data.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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