JP2013114080A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of detecting abnormality of detaching operation of a white reference plate to color measuring means without newly installing a sensor.SOLUTION: An image forming apparatus determines abnormality of attaching operation of a white reference plate 230 by a white reference plate attaching/detaching motor 314 on the basis of a measurement value of a color sensor 200 in a state where the white reference plate 230 is attached to the color sensor 200. An image forming apparatus determines abnormality of detaching operation of the white reference plate 230 by the white reference plate attaching/detaching motor 314 on the basis of a measurement value of the color sensor 200 in a state where the white reference plate 230 is detached from the color sensor 200.

Description

  The present invention relates to an image forming apparatus having a colorimetric function.

  Image quality (hereinafter referred to as image quality) of the image forming apparatus includes graininess, in-plane uniformity, character quality, color reproducibility (including color stability), and the like. In today's widespread use of multicolor image forming apparatuses, the most important image quality is sometimes referred to as color reproducibility.

  Humans have a memory of expected colors (especially human skin, blue sky, metal, etc.) based on experience, and feel uncomfortable when the tolerance is exceeded. These colors are called memory colors, and their reproducibility is often asked when outputting photographs.

  Not only for photographic images but also for document images, color reproducibility (stable) for image forming devices, such as office user groups who feel uncomfortable with the color difference from the monitor, and graphic arts user groups who pursue color reproducibility of CG images. (Including sex) is increasing.

  Therefore, an image forming apparatus that reads a measurement image (patch image) formed on a recording sheet by a color measurement unit (color sensor) provided in the conveyance path of the recording sheet in order to satisfy the user's color reproducibility requirement. It has been proposed (see, for example, Patent Document 1). According to this image forming apparatus, it is possible to reproduce a certain density, gradation, and color by applying feedback to process conditions such as exposure amount and development bias based on the result of reading a patch image by a color sensor. Is possible.

JP 2004-086013 A

  However, in the color sensor described in Patent Document 1, the chromaticity detection accuracy deteriorates due to factors such as fluctuations in the output of the light source due to changes in the environmental temperature. Therefore, it is conceivable to arrange a white reference plate at a position facing the color sensor, and measure the white reference plate with the color sensor to correct the detection value of the color sensor.

  Specifically, when the reflected light from the white reference plate is W (λ) and the reflected light from the patch image is P (λ), the spectral reflectance R (λ) of the patch image is R (λ) = P It can be obtained by (λ) / W (λ).

  When obtaining the spectral reflectance of a patch image using a white reference plate, it is necessary to place the white reference plate close to the color sensor measurement surface for measurement. The recording paper on which the patch image is formed collides with the jam. Therefore, it is necessary to provide an attachment / detachment mechanism on the white reference plate so that it is attached to the color sensor measurement surface when measuring the white reference plate and detached from the color sensor measurement surface when measuring the patch image.

  However, if the white reference plate cannot be normally operated, an error occurs in the measured value of the white reference plate, which causes an error in the spectral reflectance of the patch image. If the white reference plate cannot be removed normally, the recording paper on which the patch image is formed collides with the white reference plate and a jam occurs. On the other hand, if a sensor for detecting the attachment / detachment operation is newly provided, the cost increases.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of detecting an abnormality in the attaching / detaching operation of a white reference plate with respect to a colorimetric means without providing a new sensor.

  In order to achieve the above object, an image forming apparatus according to the present invention performs colorimetry on an image forming unit that forms a plurality of measurement images on a recording paper with a color material and the measurement image formed on the recording paper. A color measurement means for outputting spectral reflectance, a white reference plate provided at a position facing the color measurement means, an attachment / detachment means for attaching / detaching the white reference plate to / from the color measurement means, and the white reference An abnormality in the wearing operation of the white reference plate by the attaching / detaching unit is determined based on a measurement value of the color measuring unit in a state where the plate is attached to the color measuring unit, and the white reference plate is used for the color measuring unit. Discriminating means for discriminating abnormalities in the removal of the white reference plate by the attaching / detaching means on the basis of the measured value of the color measuring means in a state of being detached from

  According to the present invention, it is possible to provide an image forming apparatus capable of detecting an abnormality in the attaching / detaching operation of the white reference plate with respect to the colorimetric means.

2 is a cross-sectional view showing the structure of the image forming apparatus 100. FIG. 2 is a diagram illustrating a structure of a color sensor 200. FIG. 1 is a block diagram showing a system configuration of an image forming apparatus 100. FIG. 1 is a schematic diagram of a color management environment. 5 is a flowchart showing a calibration operation using a white reference plate 230. It is a flowchart which shows the white reference | standard board | plate attachment operation | movement 1. It is a flowchart which shows a white reference | standard board removal operation | movement. It is a flowchart which shows the white reference | standard plate attachment operation | movement 2.

(Image forming device)
In this embodiment, a solution to the above problem will be described using an electrophotographic laser beam printer. Here, as an example, an electrophotographic system is adopted as an image forming system. However, the present invention can also be applied to an ink jet method and a sublimation method. This is because the present invention is effective in an image forming apparatus in which a thermochromism phenomenon in which the chromaticity of an object to be measured changes with temperature can occur. In the ink jet system, an image forming unit that forms an image on recording paper by discharging ink and a fixing unit (drying unit) that dries the ink are used.

  FIG. 1 is a cross-sectional view illustrating the structure of the image forming apparatus 100. The image forming apparatus 100 includes a housing 101. The casing 101 is provided with various mechanisms for configuring the engine unit and a control board storage unit 104. The control board storage unit 104 stores an engine control unit 102 that performs control related to each printing process process (for example, a paper feed process) by each mechanism, and a printer controller 103.

  As shown in FIG. 1, the engine unit is provided with four stations 120, 121, 122, and 124 corresponding to YMCK. Stations 120, 121, 122, and 124 are image forming units that transfer toner onto the recording paper 110 to form an image. Here, YMCK is an abbreviation for yellow, magenta, cyan, and black. Each station is composed of almost common parts. The photosensitive drum 105 is a kind of image carrier and is charged to a uniform surface potential by a primary charger 111. A latent image is formed on the photosensitive drum 105 by the laser light output from the laser 108. The developing device 112 develops the latent image using a color material (toner) to form a toner image. The toner image (visible image) is transferred onto the intermediate transfer member 106. The visible image formed on the intermediate transfer member 106 is transferred to the recording paper 110 conveyed from the storage 113 by the transfer roller 114.

  The fixing processing mechanism of this embodiment includes a first fixing device 150 and a second fixing device 160 that heat and press the toner image transferred to the recording paper 110 and fix the toner image on the recording paper 110. The first fixing device 150 includes a fixing roller 151 for applying heat to the recording paper 110, a pressure belt 152 for pressing the recording paper 110 against the fixing roller 151, and a first post-fixing sensor for detecting completion of fixing. 153. These rollers are hollow rollers and each have a heater inside.

  The second fixing device 160 is arranged downstream of the first fixing device 150 in the conveyance direction of the recording paper 110. The second fixing device 160 imparts gloss (gloss) to the toner image on the recording paper 110 fixed by the first fixing device 150 or secures the fixing property. Similar to the first fixing device 150, the second fixing device 160 also has a fixing roller 161, a pressure roller 162, and a second post-fixing sensor 163. Depending on the type of recording paper 110, it is not necessary to pass through the second fixing device 160. In this case, the recording paper 110 passes through the transport path 130 without going through the second fixing device 160 for the purpose of reducing energy consumption.

  For example, when setting is made to add a lot of gloss to the recording paper 110, or when the recording paper 110 requires a large amount of heat for fixing like a thick paper, the recording paper 110 that has passed through the first fixing device 150 is used. Is also conveyed to the second fixing device 160. On the other hand, when the recording paper 110 is plain paper or thin paper and the setting for adding a lot of gloss is not made, the recording paper 110 is transported through a transport path 130 that bypasses the second fixing device 160. Whether the recording paper 110 is conveyed to the second fixing device 160 or whether the recording paper 110 is conveyed bypassing the second fixing device 160 is controlled by switching the flapper 131.

  The transport path switching flapper 132 is a guide member that guides the recording paper 110 to the transport path 135 or guides the recording paper 110 to the discharge path 139 to the outside. The leading edge of the recording paper 110 guided to the transport path 135 passes through the reversing sensor 137 and is transported to the reversing unit 136. When the reverse sensor 137 detects the trailing edge of the recording paper 110, the conveyance direction of the recording paper 110 is switched. The transport path switching flapper 133 is a guide member that guides the recording paper 110 to the transport path 138 for forming a double-sided image or guides the recording paper 110 to the transport path 135.

  A color sensor 200 that detects a measurement image (hereinafter referred to as a patch image) on the recording paper 110 is disposed in the conveyance path 135. Four color sensors 200 are arranged side by side in a direction orthogonal to the conveyance direction of the recording paper 110, and can detect four rows of patch images. When color detection is instructed by an instruction from the operation unit 180, the engine control unit 102 executes density adjustment, gradation adjustment, multi-order color adjustment, and the like.

  The conveyance path switching flapper 134 is a guide member that guides the recording paper 110 to the discharge path 139 to the outside. The recording paper 110 conveyed through the discharge path 139 is discharged outside the image forming apparatus 100.

(Color sensor)
FIG. 2 is a diagram illustrating the structure of the color sensor 200. Inside the color sensor 200, a white LED 201, a diffraction grating 202, a line sensor 203, a calculation unit 204, and a memory 205 are provided. The white LED 201 is a light emitting element that emits light to the patch image 220 on the recording paper 110. The light reflected from the patch image 220 passes through the sensor surface 206 made of a transparent member.

  The diffraction grating 202 separates the light reflected from the patch image 220 for each wavelength. The line sensor 203 is a light detection element that includes n light receiving elements that detect light decomposed for each wavelength by the diffraction grating 202. The calculation unit 204 performs various calculations from the light intensity value of each pixel detected by the line sensor 203.

  The memory 205 stores various data used by the calculation unit 204. The calculation unit 204 includes, for example, a spectral calculation unit that performs a spectral calculation from a light intensity value, a Lab calculation unit that calculates a Lab value, and the like. Further, a lens for condensing the light emitted from the white LED 201 onto the patch image 220 on the recording paper 110 and condensing the light reflected from the patch image 220 onto the diffraction grating 202 may be further provided.

  A change occurs in the output of the white LED 201 due to a change in the environmental temperature. In order to correct this variation, a white reference plate 230 is detachably provided on the sensor surface 206 of the color sensor 200.

  FIG. 2 shows a state where the white reference plate 230 is moved away from the sensor surface 206 for convenience of explanation (de-state), but when actually performing the measurement operation, the white reference plate 230 is brought closer to the sensor surface 206. Set to the state (wearing state). That is, when measuring the white reference plate 230, the reflected light from the white reference plate 230 is measured with the white reference plate 230 in a wearing state. Based on this reflected light, the detection value of the color sensor 200 is corrected. Hereinafter, the correction process using the white reference plate 230 is referred to as calibration.

(Profile)
In performing the multi-order color correction process, the image forming apparatus 100 creates a profile from the detection result of the patch image, converts the input image using the profile, and forms an output image.

  Here, in the patch image including multi-order colors, the dot area ratio is changed in three stages (0%, 50%, and 100%) for each of the four colors of CMYK, and all combinations of dot area ratios for each color are performed. The patch image is formed. That is, when the dot area ratio of the patch image is represented by (C, M, Y, K), the first (0%, 0%, 0%, 0%), the second (50%, 0%, 0%). , 0%), 3rd (50%, 50%, 0%, 0%) ... 81st (100%, 100%, 100%, 100%). Thus, 81 patterns (3 to the 4th power) of patch images are formed in total.

  Here, an ICC profile accepted in the market in recent years is used as a profile for realizing excellent color reproducibility. However, the present invention is not an invention that can be applied only to an ICC profile. The present invention can also be applied to CRD (Color Rendering Dictionary) adopted from Level 2 of PostScript proposed by Adobe, or a color separation table in Photoshop.

  When replacing parts by a customer engineer, before a job that requires color matching accuracy, or when you want to know the color of the final output at the design concept stage, the user operates the operation unit 180 to perform color Instructs the profile creation process.

  The profile creation process is performed in the printer controller 103 shown in the block diagram of FIG. The printer controller 103 has a CPU, and reads a program for executing a flowchart described later from the storage unit 350 and executes it. In FIG. 3, the inside of the printer controller 103 is represented by blocks in order to make the processing performed by the printer controller 103 easier to understand.

  When the operation unit 180 receives a profile creation instruction, the profile creation unit 301 outputs the CMYK color chart 210, which is an ISO12642 test form, to the engine control unit 102 without passing through the profile. The profile creation unit 301 sends a color measurement instruction to the color sensor control unit 302. The engine control unit 102 controls the image forming apparatus 100 to execute processes such as charging, exposure, development, transfer, and fixing. As a result, an ISO 12642 test form is formed on the recording paper 110. The color sensor control unit 302 controls the color sensor 200 to measure the color of the ISO12642 test form. The color sensor 200 outputs spectral reflectance data, which is a color measurement result, to the Lab calculation unit 303 of the printer controller 103. The Lab calculation unit 303 converts the spectral reflectance data into L * a * b * data and outputs it to the profile creation unit 301. Note that the Lab calculation unit 303 may convert the spectral reflectance data into the CIE 1931XYZ color system that is a color space signal independent of the device.

  The profile creation unit 301 creates an output ICC profile from the relationship between the CMYK color signal output to the engine control unit 102 and the L * a * b * data input from the Lab calculation unit 303. The profile creation unit 301 stores the created output ICC profile instead of the output ICC profile stored in the output ICC profile storage unit 305.

  The ISO12642 test form includes patches of CMYK color signals that cover a color reproduction range that can be output by a general copying machine. Therefore, the profile creation unit 301 creates a color conversion table from the relationship between each color signal value and the measured L * a * b * value. That is, a conversion table of CMYK → Lab is created. Based on this conversion table, an inverse conversion table is created.

  Upon receiving a profile creation command from the host computer via the I / F 308, the profile creation unit 301 outputs the created output ICC profile to the host computer via the I / F 308. The host computer can execute color conversion corresponding to the ICC profile with an application program.

  The first fixing driving motor is a motor for driving the first fixing device 150, the second fixing driving motor is a motor for driving the second fixing device 160, and these motors are engine controlled. Controlled by the unit 102. Further, the engine control unit 102 controls a white reference plate attaching / detaching motor 314 for attaching / detaching the white reference plate 230 to / from the sensor surface 206 of the color sensor 200. Details of this control will be described later.

(Color conversion processing)
In color conversion in normal color output, an image signal input assuming an RGB signal value input from the scanner unit via the I / F 308 or a standard print CMYK signal value such as Japan Color is an input for external input. It is sent to the ICC profile storage unit 307. The input ICC profile storage unit 307 performs RGB → L * a * b * or CMYK → L * a * b * conversion according to the image signal input from the I / F 308. The input ICC profile stored in the input ICC profile storage unit 307 includes a plurality of LUTs (lookup tables).

  These LUTs are, for example, a one-dimensional LUT that controls the gamma of the input signal, a multi-order color LUT called direct mapping, and a one-dimensional LUT that controls the gamma of the generated conversion data. The input image signal is converted from device-dependent color space to device-independent L * a * b * data using these LUTs.

  The image signal converted into L * a * b * chromaticity coordinates is input to the CMM 306. CMM is an abbreviation for color management module. The CMM 306 performs various color conversions. For example, the CMM 306 executes GUMAT conversion for mapping a mismatch between a reading color space such as a scanner unit as an input device and an output color reproduction range of the image forming apparatus 100 as an output device. In addition, the CMM 306 performs color conversion that adjusts a mismatch between a light source type at the time of input and a light source type when observing an output (also referred to as a color temperature setting mismatch).

  In this way, the CMM 306 converts the L * a * b * data into L ′ * a ′ * b ′ * data and outputs the data to the output ICC profile storage unit 305. A profile created by colorimetry is stored in the output ICC profile storage unit 305. Therefore, the output ICC profile storage unit 305 performs color conversion on the L ′ * a ′ * b ′ * data using the newly created ICC profile, converts the data into CMYK signals depending on the output device, and outputs the CMYK signal to the engine control unit 102. To do.

  In FIG. 3, the CMM 306 is separated from the input ICC profile storage unit 307 and the output ICC profile storage unit 305. However, as shown in FIG. 4, the CMM 306 is a module that manages color management, and performs color conversion using an input profile (print ICC profile 501) and an output profile (printer ICC profile 502).

(White plate attachment / detachment operation)
FIG. 5 is a flowchart showing a calibration operation using the white reference plate 230.

  This flowchart is executed by the printer controller 103. Note that the control of the image forming apparatus 100 is executed by the engine control unit 102 according to an instruction from the printer controller 103. The storage unit 350 also removes the measured value (initial value A) of the color sensor 200 when the white reference plate 230 is attached to the sensor surface 206 of the color sensor 200, which is measured when the apparatus is assembled at the factory. The measured value (initial value B) of the color sensor 200 in the state is stored in advance.

  First, the printer controller 103 places the white reference plate 230 on the sensor surface 206 of the color sensor 200 (S501). Details of the white reference plate attaching operation will be described later with reference to FIG. When the wearing operation is completed, the printer controller 103 measures the reflected light W (λ) from the white reference plate 230 by the color sensor 200 (S502).

  Next, the printer controller 103 removes the white reference plate 230 from the sensor surface 206 of the color sensor 200 (S503). Details of the white reference plate removal operation will be described later with reference to FIG. When the removal operation is completed, the printer controller 103 starts passing the recording sheet on which the patch image for measurement is formed, that is, the color chart 210 (S504).

  Next, the printer controller 103 waits until it detects the tip of the color chart 210 based on the output from the color sensor 200 (S505). Here, the printer controller 103 constantly monitors the output of the color sensor 200 and detects the timing when the amount of received light is increased as the leading edge timing of the color chart 210. A sensor for detecting the tip of the color chart 210 may be newly provided.

  When the front end of the color chart 210 is detected, the printer controller 103 causes the white reference plate 230 to be put on the sensor surface 206 of the color sensor 200 (S506). Details of the white reference plate attaching operation will be described later with reference to FIG. When the wearing operation is completed, the printer controller 103 measures the reflected light P (λ) from the patch image 220 on the color chart 210 (S507). Then, the printer controller 103 calculates the spectral reflectance of the patch image 220 as R (λ) = P (λ) / W (λ) (S508).

  Next, the printer controller 103 removes the white reference plate 230 from the sensor surface 206 of the color sensor 200 (S503), and ends the processing according to this flowchart. Details of the white reference plate removal operation will be described later with reference to FIG.

  When the white reference plate 230 is worn, the white reference plate 230 is not completely in contact with the sensor surface 206 of the color sensor 200, and the color chart 210 is between the white reference plate 230 and the sensor surface 206. There is enough space to enter.

FIG. 6 is a flowchart showing the white reference plate attaching operation 1.
This flowchart is a subroutine showing the processing of step S501 in FIG. Note that the control of the image forming apparatus 100 is executed by the engine control unit 102 according to an instruction from the printer controller 103.

  First, the printer controller 103 starts driving the white reference plate attaching / detaching motor 314 so that the white reference plate 230 is attached to the sensor surface 206 of the color sensor 200 (S601). Next, the printer controller 103 waits until a sufficient time has elapsed for the white reference plate 230 to contact the sensor surface 206 of the color sensor 200 (S602).

  Next, the printer controller 103 measures the reflected light from the white reference plate 230 by the color sensor 200 (S603), and reads the initial value A in the wearing state from the storage unit 350 (S604). Then, the printer controller 103 determines whether or not the measured value in step S603 is greater than (initial value A−α) (S605). Here, α is a value that takes into account variations due to the S / N ratio of the output signal from the color sensor 200, deterioration of the white reference plate 230, and the like. Note that (initial value A−α) corresponds to the first threshold value.

  When the measured value in step S603 is equal to or less than (initial value A−α), the measured value of the reflected light from the white reference plate 230 is too small, that is, the white reference plate 230 can be attached to the sensor surface 206 of the color sensor 200. Will not be.

  Therefore, if the printer controller 103 determines that the measured value in step S603 is greater than (initial value A−α), the printer controller 103 has successfully performed the landing operation, and thus the processing flow of this subroutine is skipped and the processing of FIG. Return to. On the other hand, if the measured value in step S603 is equal to or less than (initial value A−α), the printer controller 103 notifies the display on the operation unit 180 that the wearing operation is defective (S606). The process ends.

FIG. 7 is a flowchart showing the white reference plate removal operation.
This flowchart is a subroutine showing the processing of steps S503 and S509 in FIG. 5 and is executed by the printer controller 103. Note that the control of the image forming apparatus 100 is executed by the engine control unit 102 according to an instruction from the printer controller 103.

  First, the printer controller 103 starts driving the white reference plate attaching / detaching motor 314 so that the white reference plate 230 is detached from the sensor surface 206 of the color sensor 200 (S701). Next, the printer controller 103 waits until a sufficient time has elapsed for the white reference plate 230 to be removed from the sensor surface 206 of the color sensor 200 (S702).

  Next, the printer controller 103 measures the reflected light from the white reference plate 230 by the color sensor 200 (S703), and reads the initial value B in the detached state from the storage unit 350 (S704). Then, the printer controller 103 determines whether or not the measured value in step S703 is smaller than (initial value B + β) (S705). Here, β is a value that takes into account variations due to the S / N ratio of the output signal from the color sensor 200, deterioration of the white reference plate 230, and the like. Note that (initial value B + β) corresponds to the second threshold value. Note that the initial value B, which is the initial value in the detached state, is smaller than the initial value A, which is the initial value in the worn state.

  When the measured value in step S703 is equal to or greater than (initial value B + β), the measured value of the reflected light from the white reference plate 230 is too large, that is, the white reference plate 230 is not removed from the sensor surface 206 of the color sensor 200. It will be.

  Therefore, if the printer controller 103 determines that the measured value in step S703 is smaller than (initial value B + β), the printer controller 103 has been released normally, so that the processing flow of this subroutine is exited and the processing returns to FIG. . On the other hand, if the measured value in step S703 is equal to or greater than (initial value B + β), the printer controller 103 notifies the display on the operation unit 180 that there is a malfunction, and performs the processing according to this flowchart. finish.

FIG. 8 is a flowchart showing the white reference plate attaching operation 2.
This flowchart is a subroutine showing the processing of step S506 in FIG. 5 and is executed by the printer controller 103. Note that the control of the image forming apparatus 100 is executed by the engine control unit 102 according to an instruction from the printer controller 103.

  First, the printer controller 103 performs a measurement operation by the color sensor 200 while the white reference plate 230 is in a detached state, and obtains the measurement value 1 of the blank portion at the tip of the color chart 210 (S801). Next, the printer controller 103 starts driving the white reference plate attaching / detaching motor 314 so that the white reference plate 230 is attached to the sensor surface 206 of the color sensor 200 (S802). Next, the printer controller 103 waits until a sufficient time has elapsed for the white reference plate 230 to contact the sensor surface 206 of the color sensor 200 (S803).

  Next, the printer controller 103 performs a measurement operation by the color sensor 200, and acquires the measurement value 2 of the margin part at the tip of the color chart 210 (S804). Then, the printer controller 103 determines whether or not the measurement value 2 is larger than (measurement value 1 + σ) (S805). Here, σ is a value determined based on the amount of light increase when the white reference plate 230 is brought into contact with the back of the recording paper. Since the amount of light increase is determined by the light transmission amount of the recording paper, the value of σ may be set according to the paper type.

  When the measurement value 2 is equal to or less than (measurement value 1 + σ), the measurement value of the reflected light from the white reference plate 230 is too small, that is, the white reference plate 230 is not attached to the sensor surface 206 of the color sensor 200. .

  Therefore, if the printer controller 103 determines that the measured value 2 is larger than (measured value 1 + σ), the landing operation is normally performed, and the process exits the subroutine and returns to the process of FIG. On the other hand, if the measured value 2 is less than (measured value 1 + σ), the printer controller 103 notifies the display on the operation unit 180 that there is a defective wearing operation (S806), and ends the processing according to this flowchart.

  As described above, in this embodiment, the white reference plate 230 is attached by the white reference plate attaching / detaching motor 314 based on the measurement value of the color sensor 200 in a state where the white reference plate 230 is attached to the color sensor 200. Determine abnormal operation. Further, an abnormality in the removal of the white reference plate 230 by the white reference plate attaching / detaching motor 314 is determined based on the measurement value of the color sensor 200 in a state where the white reference plate 230 is detached from the color sensor 200. Thus, according to the present embodiment, it is possible to detect an abnormality in the attaching / detaching operation of the white reference plate 230 with respect to the color sensor 200 without newly providing a sensor.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 102 Engine control part 103 Printer controller (discriminating means)
110 Recording paper 150 First fixing device (fixing means)
160 Second fixing device (fixing means)
200 Color sensor (colorimetric means)
230 White reference plate 314 White reference plate attaching / detaching motor (detaching means)

Claims (5)

Image forming means for forming a plurality of measurement images on a recording paper with a color material;
A colorimetric means for measuring the image for measurement formed on the recording paper and outputting a spectral reflectance;
A white reference plate provided at a position facing the colorimetric means;
An attaching / detaching means for attaching / detaching the white reference plate to / from the color measuring means,
Based on the measurement value of the color measurement means in a state where the white reference plate is attached to the color measurement means, an abnormality in the wearing operation of the white reference plate by the attaching / detaching means is determined, and the white reference plate is A discriminating unit for discriminating an abnormality in the demounting operation of the white reference plate by the attaching / detaching unit based on a measurement value of the color measuring unit in a state of being removed from the color measuring unit;
An image forming apparatus comprising:   The discriminating means attaches the white reference plate by the attaching / detaching means when a measured value of the color measuring means in a state where the white reference plate is attached to the color measuring means is not more than a first threshold value. The image forming apparatus according to claim 1, wherein an abnormality is determined.   The discriminating means determines whether the white reference plate is detached by the attaching / detaching means when the measured value of the color measuring means in a state where the white reference plate is detached from the color measuring means is equal to or greater than a second threshold value. The image forming apparatus according to claim 1, wherein abnormality is determined.   3. The first threshold value is set based on an initial value of a measurement value of the color measurement unit in a state where the white reference plate is attached to the color measurement unit. Image forming apparatus.   4. The image according to claim 3, wherein the second threshold value is set based on an initial value of a measurement value of the color measurement unit in a state where the white reference plate is detached from the color measurement unit. Forming equipment.

Images