JP6057873B2 - Image forming apparatus and toner amount calculation method - Google Patents

Description

  The present invention relates to an image forming apparatus and a toner amount calculation method.

  An electrophotographic image forming apparatus such as a printer or a multifunction peripheral forms an image by taking out toner from a toner cartridge. Some of such electrophotographic image forming apparatuses measure toner consumption. Usually, the toner consumption amount is indirectly measured from image data, the number of operations of a device that transports toner from a toner cartridge, and the like (see, for example, Patent Document 1).

  In the apparatus described in Patent Document 1, in a period (first period) until the toner consumption reaches a predetermined value, the toner consumption is calculated based on the number of operations and the operation time of the apparatus that transports the toner. In a period (second period) after the toner consumption amount reaches a predetermined value, the toner consumption amount calculated based on the number of operations and the operation time of the apparatus that transports the toner is calculated based on the number of dots in the image and the image data. The toner consumption is calculated based on the data value.

  In another apparatus, the coefficient in the calculation formula for calculating the toner consumption amount in the second period is corrected based on the toner consumption amount obtained in the first period (see, for example, Patent Document 2).

JP 2005-173088 A Japanese Patent Laid-Open No. 2007-078886

  However, when determining the coefficient in the calculation formula for calculating the toner consumption based on the toner consumption calculated based on the number of operations and the operation time of the apparatus that transports the toner, the toner consumption is caused by toner blocking or the like. Since the amount varies, the coefficient is erroneously determined, and there is a possibility that the toner consumption is continuously measured erroneously.

  The present invention has been made in view of the above problems, and parameter values in a calculation formula for calculating a toner consumption amount based on a toner consumption amount calculated based on the number of operations and an operation time of an apparatus that transports toner. In the case of determining the toner amount, the object is to obtain an image forming apparatus and a toner amount calculation method that reduce the possibility that the toner consumption amount will be erroneously measured continuously.

An image forming apparatus according to the present invention includes: a first calculation unit that calculates a toner consumption amount by a first calculation method that calculates a toner consumption amount based on the number of operations or operation time of a toner conveyance unit that conveys toner from a toner cartridge ; After the predetermined switching condition is satisfied, the second calculation for calculating the toner consumption according to a predetermined calculation formula based on the data values for the plurality of pixel attributes in the image data and the parameters for each of the plurality of pixel attributes. a second calculator for calculating a preparative toner consumption in the process, the first based on the toner consumption amount calculated by the calculation method, a third repeatedly calculating the values of parameters in the equation of the second calculation method And a calculation unit. The third calculation unit causes the calculation to be performed when the parameter value is out of a predetermined allowable range, and the calculation formula is calculated based on the toner consumption calculated by the first calculation method after the calibration. When the parameter value calculated after calibration deviates from a predetermined allowable range, the toner consumption is calculated even before the switching condition is satisfied. An early switch is made from the first calculation method by the calculation unit to the second calculation method by the second calculation unit.

A toner amount calculation method according to the present invention includes a first calculation step of calculating a toner consumption amount by a first calculation method for calculating a toner consumption amount based on the number of operations or operation time of a toner conveyance unit that conveys toner from a toner cartridge. And after a predetermined switching condition is satisfied, a second calculation unit calculates toner consumption according to a predetermined calculation formula based on data values for a plurality of pixel attributes in the image data and parameters for each of the plurality of pixel attributes . a second calculation step of calculating a preparative toner consumption calculation method, based on the toner consumption amount calculated by the first calculation method, a third for calculating the value of a parameter in the formula for the second calculation method A calculation step. In the third calculation step, when the parameter value is out of a predetermined allowable range, calibration is executed, and the calculation formula is calculated based on the toner consumption calculated by the first calculation method after calibration. When the parameter value calculated after calibration deviates from a predetermined allowable range, the toner consumption is calculated even before the switching condition is satisfied. Switching from the first calculation method according to the calculation step to the second calculation method according to the second calculation step at an early stage.

  According to the present invention, when the variation of the parameter value is detected, the toner consumption calculation method is switched from the first calculation method to the second calculation method at an early stage. Compared to the case where the toner consumption amount is calculated by one calculation method, the toner consumption amount is accurately measured.

FIG. 1 is a side view showing a part of a mechanical internal configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing a part of the electrical configuration of the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a diagram for explaining the relationship between the integrated value of the operation time of the toner conveyance unit and the amount of toner supplied by the toner conveyance unit per unit operation time. FIG. 4 is a flowchart illustrating toner consumption calculation performed by the image forming apparatus according to the first embodiment. FIG. 5 is a diagram for explaining a parameter value calculation method according to the first embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.

  FIG. 1 is a side view showing a part of a mechanical internal configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus is an apparatus having an electrophotographic printing function, such as a printer, a facsimile machine, a copying machine, or a multifunction machine.

  The image forming apparatus of this embodiment has a tandem color developing device. The color developing device includes photosensitive drums 1a to 1d, an exposure device 2, and developing units 3a to 3d. The photoconductor drums 1a to 1d are four-color photoconductors of cyan, magenta, yellow, and black. The photosensitive drums 1a to 1d are made of amorphous silicon, for example.

  The exposure apparatus 2 is an apparatus that forms an electrostatic latent image by irradiating the photosensitive drums 1a to 1d with laser light while scanning. The laser beam is scanned in a direction (main scanning direction) perpendicular to the rotation direction (sub-scanning direction) of the photosensitive drums 1a to 1d. The exposure apparatus 2 has a laser scanning unit including a laser diode that is a light source of laser light and optical elements (lenses, mirrors, polygon mirrors, etc.) that guide the laser light to the photosensitive drums 1a to 1d.

  Further, around the photosensitive drums 1a to 1d, a charger such as a scorotron, a cleaning device, a static eliminator and the like are arranged. The cleaning device removes residual toner on the photosensitive drums 1a to 1d after the primary transfer, and the static eliminator neutralizes the photosensitive drums 1a to 1d after the primary transfer.

  The developing units 3a to 3d attach the toner cartridge filled with toners of four colors of cyan, magenta, yellow and black, and the toner conveyed from the toner hopper in the toner cartridge to the photosensitive drums 1a to 1d. A developing unit, and the toner is attached to the electrostatic latent images on the photosensitive drums 1a to 1d to form a toner image. The toner is transported from the toner hopper to the developing device by a toner transport unit that is operated by a driving device such as a motor (not shown).

  The photosensitive drum 1a and the developing unit 3a develop magenta, the photosensitive drum 1b and the developing unit 3b develop cyan, and the photosensitive drum 1c and the developing unit 3c develop yellow. Then, black development is performed by the photosensitive drum 1d and the developing unit 3d.

  The intermediate transfer belt 4 is an annular image carrier (intermediate transfer member) that comes into contact with the photosensitive drums 1a to 1d and primarily transfers the toner images on the photosensitive drums 1a to 1d. The intermediate transfer belt 4 is stretched around the driving roller 5 and circulates in the direction from the contact position with the photosensitive drum 1d to the contact position with the photosensitive drum 1a by the driving force from the driving roller 5.

  The transfer roller 6 brings the conveyed paper into contact with the intermediate transfer belt 4 and secondarily transfers the toner image on the intermediate transfer belt 4 to the paper. The sheet on which the toner image has been transferred is conveyed to the fixing device 9 and the toner image is fixed on the sheet.

  The roller 7 has a cleaning brush, and the cleaning brush is brought into contact with the intermediate transfer belt 4 to remove the toner remaining on the intermediate transfer belt 4 after the transfer of the toner image onto the paper.

  The sensor 8 irradiates the intermediate transfer belt 4 with a light beam, and detects reflected light from the surface of the intermediate transfer belt 4 or a toner pattern on the surface. For example, the sensor 8 irradiates a predetermined region of the intermediate transfer belt 4 with a light beam and detects reflected light of the light beam and outputs an electric signal corresponding to the light amount at the time of calibration of gradation and maximum toner density. .

  FIG. 2 is a block diagram showing a part of the electrical configuration of the image forming apparatus according to the embodiment of the present invention. As illustrated in FIG. 2, the image forming apparatus includes a communication device 11, an arithmetic processing device 12, and a printing device 13.

  The communication device 11 can be connected to a host device via a network or a peripheral device interface, and performs data communication using a predetermined communication protocol.

  The arithmetic processing unit 12 is a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and loads a program from a storage device, ROM, etc. (not shown) to the RAM. Various processing units are realized by executing the program by the CPU.

  The printing apparatus 13 is an internal device that prints a document image with a mechanical configuration as shown in FIG.

  After the image forming apparatus is activated, various programs are appropriately executed by the arithmetic processing unit 12. In this embodiment, the arithmetic processing unit 12 implements processing units such as an operating system (not shown), a communication processing unit 21, a print request processing unit 22, an image processing unit 23, a controller 24, and a toner consumption calculation unit 25. The

  The communication processing unit 21 is a processing unit that controls the communication device 11 to execute data communication with a host device or the like. For example, the communication processing unit 21 receives document data as a print request from the host device.

  The print request processing unit 22 receives a print request based on a user operation on the operation panel or a print request supplied from the host device, and executes a print job corresponding to the request. For example, when document data in a predetermined data format such as PDL (Page Description Language) or PDF (Portable Document Format) is received as a print request from the host device, the print request processing unit 22 reads image data from the document data. Is generated. This image data is bitmap data, and when the original data of bitmap data is received from the host device, the print request processing unit 22 uses the original data as image data as it is.

  The image processing unit 23 executes predetermined image processing on the image data, and generates print data (for example, print image data binarized for each color). The image processing unit 23 includes a pixel attribute determination unit 31 and a screen processing unit 32.

  The pixel attribute determination unit 31 specifies the pixel attribute of each pixel from the attribute data of each pixel in the image data, and specifies the character area, the gradation area (area having a halftone such as a photograph), etc. in the image data. .

  The screen processing unit 32 generates print data by a predetermined screen method. The screen processing unit 32 may change the screen method according to the pixel attribute specified by the pixel attribute determination unit 31.

  The controller 24 is a processing unit that monitors and controls an internal device such as the printing apparatus 13. The controller 24 controls an unillustrated drive source for driving the above-described roller, a bias application circuit for applying a development bias and a primary transfer bias, and the exposure device 2 to develop, transfer and fix a toner image, and It is a processing circuit for executing paper feeding, printing, and paper ejection. The developing bias is applied between the photosensitive drums 1a to 1d and the developing units 3a to 3d, respectively, and the primary transfer bias is applied between the photosensitive drums 1a to 1d and the intermediate transfer belt 4, respectively. In particular, the controller 24 controls a driving device that operates the above-described toner conveyance unit, and controls toner conveyance in the developing units 3a to 3d.

  Further, the toner consumption calculation unit 25 calculates the toner consumption accompanying printing by the printing apparatus 13. Further, the toner consumption calculation unit 25 calculates the remaining amount of toner in the toner cartridge from the toner consumption. Further, the toner consumption amount calculation unit 25 displays the toner consumption amount and the toner remaining amount on an operation panel (not shown), or displays a warning message on an operation panel (not shown) when the toner remaining amount is low. To do.

  The toner consumption amount calculation unit 25 includes a first calculation unit 41, a second calculation unit 42, and a coefficient calculation unit 43.

  The first calculation unit 41 repeatedly calculates the toner consumption amount by the first calculation method until a predetermined switching condition is satisfied. In the first embodiment, the first calculation method is a method of calculating the toner consumption based on the number of operations or the operation time (integrated value of the operation time) of the toner conveyance unit that conveys toner from the toner cartridge. In the first embodiment, the switching condition is that the integrated value of the toner consumption calculated by the first calculation method reaches a predetermined threshold (for example, 90% of the total amount of toner in the toner cartridge). The predetermined threshold value is a value within a range in which the toner supply time and the integrated value of the toner consumption are approximately proportional to each other, and is determined in advance by an experiment or the like.

  The second calculation unit 42 calculates the toner consumption amount according to a predetermined calculation formula using the second calculation method after the predetermined switching condition is satisfied. In the first embodiment, the second calculation unit 42 includes data values (pixel values of image data before screen processing or presence / absence of dots after screen processing) for a plurality of pixel attributes in image data and a plurality of pixel attributes. Toner consumption is calculated based on the parameters for each. More specifically, in the first embodiment, the second calculation unit 42 calculates the product of the print rate for a plurality of pixel attributes in the image data and the parameter (ie, coefficient) for each of the plurality of pixel attributes. The toner consumption is calculated based on the sum. Note that the pixel attribute of each pixel is specified by the pixel attribute specifying unit 31 based on attribute data included in the image data, for example.

  In the first embodiment, the number of the plurality of pixel attributes is 2, one of the plurality of pixel attributes is a character attribute, and the other is a gradation attribute. In the first embodiment, the number of measurement periods is the same as the number of pixel attributes (that is, 2). In Embodiment 1, the length of each of the plurality of measurement periods is set to be sufficiently longer than the fluctuation period of the toner consumption calculated by the first calculation method. Note that the number of the plurality of pixel attributes may be three or more. Further, the number of the plurality of measurement periods may be larger than the number of the plurality of pixel attributes.

  The coefficient calculator 43 repeatedly calculates the parameter values in the calculation formula of the second calculation method based on the toner consumption calculated by the first calculation method. In the first embodiment, the parameter is a coefficient for each pixel attribute used by the second calculator 42. In the first embodiment, the coefficient calculation unit 43 calculates data values for a plurality of pixel attributes in a plurality of measurement periods, and corresponds to the toner consumption and the plurality of measurement periods calculated by the first calculation method in the measurement period. The parameter value is calculated from the calculated data value. More specifically, the coefficient calculation unit 43 calculates the printing rate for a plurality of pixel attributes in a plurality of measurement periods, and corresponds to the toner consumption and the plurality of measurement periods calculated by the first calculation method in the measurement period. The value of the parameter is calculated from the print ratio calculated in the above.

  Further, when the parameter value is out of a predetermined allowable range, the coefficient calculation unit 43 causes the controller 24 and the like to execute the calibration of the gradation and the maximum toner density, and the toner calculated by the first calculation method after the calibration. When the parameter value in the calculation formula is calculated based on the consumption amount, and the parameter value calculated after the calibration is out of the predetermined allowable range, the toner consumption amount even before the above switching condition is satisfied. Is quickly switched from the first calculation method by the first calculation unit 41 to the second calculation method by the second calculation unit 42.

  In addition, when the calculation of the toner consumption is switched from the first calculation method by the first calculation unit to the second calculation method by the second calculation unit at an early stage, the second calculation unit 42 sets the parameters calculated in the past. The toner consumption is calculated by the second calculation method using the average value as the parameter value in the calculation formula. If the parameter value does not fall within the predetermined allowable range, the second calculation unit 42 uses the parameter value obtained in the experiment as the parameter value in the calculation formula, and uses the second calculation method to consume the toner. Calculate the quantity.

  Next, the operation of the image forming apparatus will be described.

  FIG. 3 is a diagram for explaining the relationship between the integrated value of the operation time of the toner conveyance unit and the amount of toner supplied by the toner conveyance unit per unit operation time.

  In the developing units 3a to 3d, toner is supplied from the toner cartridge to the developing device. The toner transport unit performs the toner transport operation for a predetermined operation time in one operation, and supplies the toner from the toner cartridge to the developing device. The amount of toner supplied in one operation is almost constant when there is a large amount of remaining toner, but it is almost constant, but as the remaining amount of toner decreases, it decreases as the remaining amount of toner decreases. At the same time, the fluctuation increases.

  For this reason, when the remaining amount of toner is large, the first calculation unit 41 acquires information on the number of operations or operation time of the toner transport unit from the controller 24 and calculates the toner consumption amount by the first calculation method. While calculating the toner consumption accurately by the first calculation method, the coefficient calculation unit 43 calculates the values of parameters used in the second calculation method. On the other hand, when the remaining amount of toner is low, the second calculation unit 42 uses the parameter value calculated by the coefficient calculation unit 43 based on the image data before or after the screen processing, to the toner by the second calculation method. Calculate consumption.

  FIG. 4 is a flowchart illustrating toner consumption calculation performed by the image forming apparatus according to the first embodiment. FIG. 5 is a diagram for explaining a parameter value calculation method according to the first embodiment.

First, when the toner remaining amount of the toner cartridge is 100%, such as when the toner cartridge is replaced, the first calculation unit 41 resets the integrated value of the toner consumption amount to zero, and calculates the toner consumption amount by the first calculation method. Calculation is started (step S1). Thereafter, each time the printing apparatus 13 performs an operation involving toner consumption such as a printing operation or density correction, the first calculation unit 41 calculates a toner consumption amount for the operation, and based on the toner consumption amount, The toner consumption amount integrated value and the toner remaining amount value are updated.

Thereafter, the coefficient calculation unit 43 monitors the integrated value of the toner consumption calculated by the first calculation unit 41. When the integrated value of the toner consumption reaches a predetermined value, the coefficient calculation unit 43 measures the printing rate in the first measurement period. Start (step S2).

  The coefficient calculation unit 43 stores the integrated value of the toner consumption amount at the start of the printing rate measurement in the first measurement period, and the increase amount of the integrated value of the toner consumption amount is set to a predetermined threshold To (for example, 50 grams). Until it reaches, the printing rate measurement in the first measurement period is continued. At this time, as shown in FIG. 5, the coefficient calculation unit 43 calculates the print rate of each page from the number of dots in the image data (print data) after the screen processing, for each pixel attribute (step S3). That is, the printing rate X1i of the character attribute area and the printing rate Y1i of the gradation attribute area are calculated.

  Then, when the increase amount of the integrated value of the toner consumption reaches a predetermined threshold value To, the coefficient calculation unit 43 ends the printing rate measurement in the first measurement period (step S4). The coefficient calculation unit 43 calculates the sums Xt1 and Yt1 of the printing rates for the character attribute area and the gradation attribute area in the first measurement period.

  When the integrated value of the toner consumption reaches a predetermined value after the end of the first measurement period, the coefficient calculation unit 43 starts the print rate measurement in the second measurement period (step S5), and the print rate for each pixel attribute. (Step S6), and when the increase amount of the integrated value of toner consumption from the start of the second measurement period reaches a predetermined threshold value To (for example, 50 grams), the printing rate measurement in the second measurement period is performed. The process ends (step S7). The coefficient calculation unit 43 calculates the sums Xt2 and Yt2 of the printing rates for the character attribute area and the gradation attribute area in the second measurement period.

  Then, after the end of the second measurement period, the coefficient calculation unit 43 performs the above-described threshold value To, the sums Xt1 and Yt1 of the print ratios for the pixel attributes in the first measurement period, and the pixel attributes in the second measurement period. As shown in FIG. 5, the values of parameters (here, coefficients a and b) in the calculation formula for calculating the toner consumption from the printing rate in the second calculation method based on the total printing rate Xt2 and Yt2 Is calculated (step S8).

  Here, the coefficient calculation unit 43 determines whether or not the values of the coefficients a and b are out of a predetermined allowable range (step S9).

  For example, when the reference values of the coefficients a and b obtained by experiments are a = 0.03 and b = 0.07, the allowable range of the coefficient a is 0.02 to 0.05, and the coefficient b The allowable range is 0.06 to 0.10.

  When the values of the coefficients a and b are both within the allowable range, the coefficient calculation unit 43 determines whether or not the integrated value of the toner consumption has reached a predetermined reference value (step S10). If the integrated value of toner consumption has not reached the predetermined reference value, the process returns to step S2.

  On the other hand, when at least one of the values of the coefficients a and b is outside the predetermined allowable range, the coefficient calculation unit 43 causes the calibration to be performed, and after the calibration, the same processing as the processing in steps S2 to S8 is performed. (Step S12). Then, the coefficient calculation unit 43 determines whether or not the values of the coefficients a and b calculated after the calibration are outside a predetermined allowable range (step S13).

  When the values of the coefficients a and b calculated after the calibration are out of the predetermined allowable range, the coefficient calculation unit 43 determines that the variation of the coefficient values is large, and calculates the toner consumption amount by using the first calculation unit 41. The first calculation method according to the above is switched to the second calculation method according to the second calculation unit 42 at an early stage (step S14).

  When the values of the coefficients a and b calculated after the calibration are within a predetermined allowable range, the coefficient calculation unit 43 does not determine that the coefficient value variation is large here, and proceeds to step S10.

  Thereafter, in step S10, when the coefficient calculation unit 43 determines that the integrated value of the toner consumption amount has reached a predetermined reference value, the calculation of the toner consumption amount is changed from the first calculation method by the first calculation unit 41 to the second calculation method. The calculation unit 42 switches to the second calculation method (step S14). In this case, as the coefficients a and b in the second calculation method, the last measured value or the average value similar to the above is used.

  When the calculation of the toner consumption amount is switched from the first calculation method by the first calculation unit 41 to the second calculation method by the second calculation unit 42, the second calculation unit 42 starts calculating the toner consumption amount. The second calculating unit 42 calculates the printing rate of each page for each pixel attribute according to the following equation until the remaining amount of toner in the toner cartridge becomes zero or the toner cartridge is replaced, and the printing rate and coefficient calculating unit Based on the parameter value calculated by 43, the toner consumption amount of each page is calculated, and the integrated value of the toner consumption amount is updated with the toner consumption amount (step S15).

  T = a × X + b × Y

  However, T is the toner consumption amount of one page, X is the printing rate of the character attribute area, and Y is the printing rate of the gradation attribute area.

  As described above, according to the first embodiment, the first calculation unit 41 repeatedly calculates the toner consumption amount by the first calculation method until the predetermined switching condition is satisfied, and the second calculation unit 42 After the switching condition is satisfied, the toner consumption is calculated according to a predetermined calculation formula by the second calculation method. The coefficient calculation unit 43 repeatedly calculates parameter values in the second calculation method based on the toner consumption calculated by the first calculation method. Then, when the parameter value is out of the allowable range, the coefficient calculation unit 43 executes calibration, and calculates the parameter value in the calculation formula based on the toner consumption calculated by the first calculation method after calibration. When the parameter value is out of the allowable range, the toner consumption amount is calculated from the first calculation method by the first calculation unit 41 to the second calculation even before the above switching condition is satisfied. Switch to the second calculation method by the unit 42 at an early stage.

  Thus, when the parameter value variation is detected, the toner consumption calculation method is switched from the first calculation method to the second calculation method at an early stage. Therefore, the first calculation method is continued until the switching condition is satisfied. Compared with the case where the toner consumption amount is calculated in step 1, the toner consumption amount is measured more accurately.

Embodiment 2. FIG.

  In the first embodiment, the toner consumption calculation unit 25 calculates the printing rate from the image data (print data) after the screen processing. In the image forming apparatus according to the second embodiment, the toner consumption calculation unit 25 The printing rate is calculated from the pixel value of the image data before screen processing. Since the configuration and other operations of the image forming apparatus according to the second embodiment are the same as those of the first embodiment, description thereof is omitted.

  Each embodiment described above is a preferred example of the present invention, but the present invention is not limited to these, and various modifications and changes can be made without departing from the scope of the present invention. It is.

  For example, in each of the above-described embodiments, the present invention is applied to a color image forming apparatus. However, it is of course possible to apply the present invention to a monochrome image forming apparatus.

  Further, in each of the above embodiments, the pixel attributes are two of the character attribute and the gradation attribute, but may be three of the character attribute, the vector graphic attribute, and the gradation attribute. In this case, the number of parameters is three, and the toner consumption amount is calculated by linear combination of the printing rates of the character attribute, the vector graphic attribute, and the gradation attribute. Since the number of parameters is 3, the above-described measurement period is set to 3 or more.

  In each of the above embodiments, the value of the parameter (b) described above for the gradation attribute in a plurality of pixel attributes is fixed, and the second calculation unit 42 performs the remaining one or more pixel attributes (for example, character The toner consumption is calculated based on the data value for the attribute) and the parameters for the remaining one or more pixel attributes, and the coefficient calculation unit 43 calculates the remaining 1 calculated in each of the one or more measurement periods. Alternatively, parameter values for the remaining one or more pixel attributes are calculated from the data values for the plurality of pixel attributes and the toner consumption calculated by the first calculation method in each of the one or more measurement periods. . As a result, in an image forming apparatus that performs density correction for the tone characteristics of toner density, the toner consumption amount can be measured more accurately by using parameter values based on the result of density correction for pixels with tone attributes. Is done.

  The present invention is applicable to, for example, an electrophotographic image forming apparatus.

41 1st calculation part 42 2nd calculation part 43 Coefficient calculation part (an example of a 3rd calculation part)

Claims (3)

In an image forming apparatus that performs printing using toner,
A first calculation unit that repeatedly calculates toner consumption by a first calculation method that calculates toner consumption based on the number of operations or operation time of a toner conveyance unit that conveys toner from a toner cartridge ;
A second calculation method for calculating toner consumption according to a predetermined calculation formula based on data values for a plurality of pixel attributes in the image data and parameters for each of the plurality of pixel attributes after a predetermined switching condition is satisfied. a second calculator for calculating a preparative toner consumption in,
The first, based on the toner consumption amount calculated by the calculation method, and a third calculation unit for calculating repeatedly a value of the parameters in the equation of the second calculation method,
The third calculation unit performs calibration when the value of the parameter is out of a predetermined allowable range, and sets the parameter in the calculation formula based on the toner consumption calculated by the first calculation method after calibration. When the parameter value calculated after the calibration is out of a predetermined allowable range, the toner consumption amount is calculated even before the switching condition is satisfied. Early switching from the first calculation method according to the second calculation method by the second calculation unit;
An image forming apparatus.   When the calculation of the toner consumption is quickly switched from the first calculation method by the first calculation unit to the second calculation method by the second calculation unit, the second calculation unit is calculated in the past. The image forming apparatus according to claim 1, wherein the toner consumption is calculated by the second calculation method using an average value of the parameter values as a parameter value in the calculation formula. A first calculation step of calculating a toner consumption amount by a first calculation method for calculating a toner consumption amount based on the number of operations or the operation time of a toner conveying unit that conveys toner from a toner cartridge ;
A second calculation method for calculating toner consumption according to a predetermined calculation formula based on data values for a plurality of pixel attributes in the image data and parameters for each of the plurality of pixel attributes after a predetermined switching condition is satisfied. a second calculation step of calculating a preparative toner consumption in,
A third calculation step of calculating a parameter value in the calculation formula of the second calculation method based on the toner consumption calculated by the first calculation method;
With
In the third calculation step, when the value of the parameter is out of a predetermined allowable range, calibration is executed, and the parameter in the calculation formula is calculated based on the toner consumption calculated by the first calculation method after calibration. When the parameter value calculated after the calibration is out of a predetermined allowable range, the toner consumption is calculated even before the switching condition is satisfied. Early switching from the first calculation method according to the second calculation method according to the second calculation step;
A toner amount calculation method characterized by the above.

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