JP6237673B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including a storage container that stores toner to be supplied to a developing unit for each color, and stores a stirring transport member that stirs and transports the toner.

  A general image forming apparatus includes a detection device that detects the amount of toner in the developing unit. Such a detection device has a CR oscillation circuit composed of a capacitor having a capacitance that changes according to the remaining amount of toner in the developing unit, and oscillates a pulse frequency having a different frequency according to the remaining amount of toner. And a pulse oscillating means for detecting the amount of toner remaining on the basis of the pulse signal generated by the pulse oscillating means. As a means for detecting the remaining amount of ink in an ink tank of an ink jet printer, there is one disclosed in Patent Document 1 below.

Japanese Patent Application Laid-Open No. 10-1000043

  The conventional detecting means counts the frequency of the pulse signal generated by the pulse oscillating means and detects the remaining amount of toner based on the counted frequency. Therefore, there is a resource for counting the oscillation frequency of the pulse signal. I need it. As a resource for counting the frequency, a timer function of a CPU (Central Processing Unit) is generally used.

  In an image forming apparatus that performs general color printing, a toner container and a developing unit are mounted for the amount of toner. Therefore, in order for the CPU to detect the remaining amount of toner in the storage container using the timer function described above, the timer resource of the CPU is required for each toner color, and thus there is a problem that the timer resource increases. .

  The present invention has been made to solve the above-described problem, and an object of the present invention is to make it possible to detect the remaining amount of toner in each color storage container while reducing an increase in timer resources as compared with the conventional technique.

An image forming apparatus according to an aspect of the present invention includes a plurality of storage containers that store toner to be supplied to a developing unit for each color, and have a toner supply port for supplying the toner on one end side;
A stirring / conveying member that is rotatably provided to each of the plurality of storage containers and has a rotation shaft extending from the one end portion toward the other end portion and conveys the toner to the toner supply port while stirring the toner. When,
A rotation driving unit that is provided for each of the plurality of storage containers and that rotates the stirring and conveying member;
A remaining toner sensor that is provided for each of the plurality of storage containers and detects the remaining amount of the toner;
A sampling unit that samples an output value of the toner remaining amount sensor for each color when the rotation driving unit is rotating the stirring conveyance member;
The period in which the stirring and conveying member rotates once is divided into a plurality of predetermined sampling periods, the sampling period is further divided for each color, and the divided sections are sampled for each color by the sampling unit. And a sampling period setting unit that is set as
The sampling unit obtains the remaining amount of toner from the toner remaining amount sensor of each color for each of the sampling periods set by the sampling period setting unit.

  According to the present invention, it is possible to detect the remaining amount of toner in the storage containers of the respective colors while reducing the increase in timer resources as compared with the prior art.

1 is a front sectional view showing a structure of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a side sectional view illustrating an outline of an internal configuration of a toner container. 2 is a functional block diagram illustrating a main internal configuration of the image forming apparatus. FIG. 6 is a graph illustrating an example of an output value from a toner remaining amount sensor. (A) (B) is a figure for demonstrating the sampling process by a sampling part. 10 is a flowchart illustrating an example of a process for changing a sampling period of a remaining amount of toner of each color.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view showing the structure of an image forming apparatus according to an embodiment of the present invention.

  An image forming apparatus 1 according to an embodiment of the present invention is a multifunction machine having a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function. The image forming apparatus 1 includes an apparatus main body 11 that includes an operation unit 47, an image forming unit 12, a fixing unit 13, a paper feeding unit 14, a document feeding unit 6, a document reading unit 5, and the like.

  The operation unit 47 receives instructions such as an image forming operation execution instruction and a document reading operation execution instruction from the operator regarding various operations and processes that can be executed by the image forming apparatus 1. The operation unit 47 includes a display unit 473. The display unit 473 is configured by an LCD (Liquid Crystal Display) having a touch panel function.

  When the image forming apparatus 1 performs a document reading operation, the document reading unit 5 optically reads a document fed by the document feeding unit 6 or a document placed on the document placing glass 161, Generate image data. Image data generated by the document reading unit 5 is stored in a built-in HDD or a network-connected computer.

  When the image forming apparatus 1 performs an image forming operation, it is based on image data generated by the document reading operation, image data received from a computer connected to a network, image data stored in a built-in HDD, or the like. Then, the image forming unit 12 forms a toner image on the recording paper P as a recording medium fed from the paper feeding unit 14. When performing color printing, the magenta image forming unit 12M, the cyan image forming unit 12C, the yellow image forming unit 12Y, and the black image forming unit 12Bk of the image forming unit 12 respectively A toner image is formed on the photosensitive drum 121 by charging, exposure, and development processes based on an image composed of each color component constituting data, and the toner image is formed on the intermediate transfer belt 125 by the primary transfer roller 126. Let them transcribe.

  The toner images of the respective colors transferred onto the intermediate transfer belt 125 are superimposed on the intermediate transfer belt 125 with the transfer timing adjusted to form a color toner image. The secondary transfer roller 210 passes the toner image of the color formed on the surface of the intermediate transfer belt 125 from the paper supply unit 14 through the conveyance path 190 at the nip portion N with the driving roller 125A across the intermediate transfer belt 125. It is transferred to the recording paper P that has been conveyed. Thereafter, the fixing unit 13 fixes the toner image on the recording paper P to the recording paper P by thermocompression bonding. The recording paper P on which the color image has been formed after completion of the fixing process is discharged to a discharge tray 151.

  In the case of performing double-sided printing in the image forming apparatus 1, the recording paper P having an image formed on one side by the image forming unit 12 is nipped by the discharge roller pair 159, and then the recording paper P is switched back by the discharge roller pair 159 and sent to the reverse conveyance path 195, and the conveyance roller pair 19 conveys the recording paper P again upstream in the conveyance direction of the recording paper P with respect to the nip portion N and the fixing unit 13. As a result, an image is formed on the other surface of the recording paper by the image forming unit 12.

  The developing unit 122M in the image forming unit 12M, the developing unit 122C in the image forming unit 12C, the developing unit 122Y in the image forming unit 12Y, and the developing unit 122Bk in the image forming unit 12Bk are respectively magenta (M), cyan (C), Development processing of yellow (Y) and black (Bk) is performed. To the position away from these developing units 122M, 122C, 122Y, and 122Bk, specifically, a toner container 61M that stores magenta toner, a toner container 61C that stores cyan toner, and yellow above the intermediate transfer belt 125, yellow A toner container 61 </ b> Y that stores toner and a toner container 61 </ b> Bk that stores black toner are detachably mounted on a toner container mounting portion (not shown) provided in the apparatus main body 11. When the toner has been used up, the toner containers 61M, 61C, 61Y, 61Bk can be replaced as necessary by opening and closing a container cover (not shown) provided in the apparatus main body 11.

  Each of the toner containers 61M, 61C, 61Y, 61Bk has a toner supply port 617 (see FIG. 2) formed in the bottom surface. The toner replenishing port is connected to the inside of the corresponding developing unit among the developing units 122M, 122C, 122Y, and 122Bk through a pipe (not shown) installed in the apparatus main body 11 in a substantially vertical posture. The toner containers 61M, 61C, 61Y, and 61Bk are examples of storage containers in the claims.

  FIG. 2 is a side sectional view showing an outline of the internal configuration of the toner container 61M. The toner containers 61C, 61Y, 61Bk and the developing units 122C, 122Y, 122Bk have the same configuration as the toner container 61M and the developing unit 122M, and thus the description thereof is omitted.

  The toner container 61M is provided with a toner reservoir 611, an agitating and conveying screw 615, and a motor 70.

  The toner storage unit 611 stores toner to be supplied to the developing unit 122M, and has a toner supply port 617 for the developing unit 122M on the one end 611A side. A stirring and conveying screw 615 is provided from the other end 611B of the toner storage unit 611 to the one end 611A. The agitating and conveying screw 615 conveys the toner to the toner replenishing port 617 while agitating the toner. The agitating and conveying screw 615 is an example of an agitating and conveying member in the claims.

  The agitating / conveying screw 615 is rotatably provided in the toner storage unit 611, and includes a rotation shaft 615A and a spiral 615B provided in a spiral shape around the rotation shaft 615A. The rotation shaft 615A extends in the direction from the other end 611B toward the one end 611A. For example, one end of the rotation shaft 615 </ b> A is attached to one end 611 </ b> A of the toner storage unit 611. A gear 6150 that meshes with a gear 750 provided in the motor 70 is provided at the other end of the rotating shaft 615A.

  When the rotating shaft 615A of the agitating and conveying screw 615 is rotated by receiving the rotational driving force from the motor 70, the toner in the toner storage unit 611 is directed toward the toner supply port 617 by the spiral 615B that rotates together with the rotating shaft 615A. Be transported. The toner conveyed to the toner supply port 617 falls from the toner supply port 617 to the developing unit 122M due to its own weight. As a result, toner is supplied to the developing unit 122M.

  A toner remaining amount sensor 17 is provided on the side of the apparatus main body 11 at a position facing the one end 611A of the toner storage unit 611. The toner remaining amount sensor 17 is provided for the toner container 61M and detects the remaining amount of toner stored in the toner container 61M, in particular, the remaining amount of toner present in the one end 611A of the toner storage unit 611. The toner remaining amount sensor 17 outputs a voltage value corresponding to the toner remaining amount. A similar toner remaining amount sensor 17 is also provided for each of the toner containers 61C, 61Y, 61Bk, detects the remaining amount of toner stored in each container, and sets a voltage value corresponding to the remaining amount of toner. Output.

  FIG. 3 is a functional block diagram showing the main internal configuration of the image forming apparatus 1. The image forming apparatus 1 includes a control unit 10, a document feeding unit 6, a document reading unit 5, an image forming unit 12, an HDD 92, a fixing unit 13, a motor 70, a driver 700, an operation unit 47, a facsimile communication unit 71, and a network interface unit. 91, a toner remaining amount sensor 17 and the like. In addition, the same number is attached | subjected to the same component as demonstrated using FIG. 1, and description is abbreviate | omitted.

  The document reading unit 5 includes a reading mechanism 163 (FIG. 1) having a light irradiation unit and a CCD sensor. The document reading unit 5 reads an image from the document by irradiating the document with the light irradiating unit and receiving the reflected light with a CCD sensor.

  The HDD 92 is a large-capacity nonvolatile storage device that stores image data and the like of a document read by the document reading unit 5.

  The motor 70 supplies a rotational driving force to the stirring and conveying screw 615. The driver 700 drives the motor 70 under an instruction from the control unit 100. The motor 70 and the driver 700 are provided in each color toner container, and are an example of a rotation drive unit in the claims.

  The facsimile communication unit 71 includes an unillustrated encoding / decoding unit, modulation / demodulation unit, and NCU (Network Control Unit), and performs facsimile transmission using a public telephone network.

  The network interface unit 91 includes a communication module such as a LAN board, and transmits / receives various data to / from an external device 20 such as a personal computer in a local area or the Internet via a LAN connected to the network interface unit 91. I do.

  The control unit 10 includes a CPU, a RAM, a ROM, a dedicated hardware circuit, and the like. The control unit 10 includes a control unit 100, a sampling unit 101, and a sampling period setting unit 102.

  The control unit 100 governs overall operation control of the image forming apparatus 1. The control unit 100 includes a document feeding unit 6, a document reading unit 5, an image forming unit 12, an HDD 92, a fixing unit 13, a driver 700, an operation unit 47, a facsimile communication unit 71, a network interface unit 91, and a toner remaining amount sensor 17. Etc., and control these parts.

  The sampling unit 101 displays the output value of the toner remaining amount sensor 17, that is, the toner remaining amount detected by the toner remaining amount sensor 17 when the stirring and conveying screw 615 is rotationally driven by the motor 70 and the driver 700. Sampling is performed for each color of (M), cyan (C), yellow (Y), and black (Bk). The sampling unit 101 performs the sampling a plurality of times while the stirring and conveying screw 615 rotates once. This is because the remaining amount of toner changes according to the rotation of the agitating / conveying screw 615, so that the sampling following the change in the remaining amount of toner accompanying the rotation of the agitating / conveying screw 615 is realized.

  The sampling period setting unit 102 divides the period of one rotation of the stirring and conveying screw 615 into a plurality of predetermined sampling periods, and further divides the sampling period into magenta (M), cyan (C), yellow (Y), and black This is divided for each color of (Bk), and each divided section is set as a sampling period for each color by the sampling unit 101 (hereinafter referred to as a first sampling period).

  The control unit 10 functions as the control unit 100, the sampling unit 101, and the sampling period setting unit 102 by operations according to the operation control program. However, the control unit 100, the sampling unit 101, and the sampling period setting unit 102 can be configured by hardware circuits without depending on the operation according to the operation control program by the control unit 10.

  Next, an example of the toner remaining amount sampling operation according to the present embodiment will be described with reference to FIG. FIG. 4 is a graph showing an example of the output value V [bit] from the toner remaining amount sensor 17. The output value V [bit] from the toner remaining amount sensor 17 indicates that the higher the value, the larger the toner amount. The horizontal axis of the graph represents the stirring time [ms]. 4A to 4D show waveforms W1 to W4 of the output value V from the remaining toner sensor 17 provided for each of the toner containers 61M, 61C, 61Y, and 61Bk.

  4A to 4D, the waveforms W1 to W4 are shown in the same shape in order to simplify the description of the detection operation.

  In this example, at time t1, the driver 700 starts driving the motor 70 under an instruction from the control unit 100. Accordingly, the agitating and conveying screw 615 provided for each of the toner containers 61M, 61C, 61Y, and 61Bk starts to rotate at time t1. In addition, the code | symbol T shown to FIG. 4 (A)-(D) is time which shows the period which each stirring conveyance screw 615 rotates once.

  For example, the sampling period setting unit 102 divides the period T shown in FIG. 4A into a plurality of predetermined sampling periods, and further divides the sampling period into magenta (M), cyan (C), yellow (Y), And black (Bk), and the divided sections are set as sampling periods TM, TC, TY, and TBk for each color by the sampling unit 101.

  In this example, the sampling period setting unit 102 divides the cycle T into a plurality of (for example, 20) sections at the sampling cycle Tmin shown in FIG. 4A, and then divides the sampling cycle Tmin to perform sampling for each color. Periods TM, TC, TY, and TBk are set.

  For example, the sampling unit 101 samples the output value V from the toner remaining amount sensor 17 for the corresponding color once in each sampling period. That is, when the sampling period TM has come, the sampling unit 101 acquires the toner remaining amount detected by the magenta toner remaining amount sensor 17 once. Even at the arrival of the sampling periods TC, TY, and TBk, the sampling unit 101 acquires the remaining toner amount detected by the remaining toner sensor 17 for each corresponding color once. That is, in the sampling period Tmin, the output value V from the toner remaining amount sensor 17 of each color is sampled sequentially for all colors of magenta (M), cyan (C), yellow (Y), and black (Bk). It is the time used for The order of sampling each color is not limited to the order of magenta (M), cyan (C), yellow (Y), and black (Bk), but can be changed.

  FIG. 5A is a diagram for describing sampling processing by the sampling unit 101. The sampling unit 101 measures the arrival of the sampling period Tmin with one timer, and measures the arrival of the sampling periods TM, TC, TY, and TBk for each color from the arrival of the sampling period Tmin. That is, in this embodiment, the sampling periods TM, TC, TY, and TBk for all colors are ensured within one sampling period Tmin in which one timer measures arrival. The sampling unit 101 does not measure the arrival of the sampling periods TM, TC, TY, and TBk for each color by using separate timers provided for the respective colors.

  For example, the sampling unit 101 starts sampling the output value V of the toner remaining amount sensor 17 at the same timing as time t1 when the stirring and conveying screw 615 starts to rotate, that is, in synchronization with the rotation of the stirring and conveying screw 615. To do. During the period from time t1 to time t2 (= t1 + T) when each stirring and conveying screw 615 rotates once, the sampling unit 101 performs magenta (M), cyan (C), yellow (Y), and black (Bk). In order, every time the sampling period Tmin (sampling period) arrives, the output value V from each toner remaining amount sensor 17 is sampled a plurality of times (for example, 20 times).

  The sampling unit 101 calculates, for each color, the average value of the output values V during the period in which the stirring and conveying screw 615 rotates based on the output value V acquired every time the sampling cycle Tmin (sampling period) arrives. Calculate and output each average value. That is, the sampling unit 101 detects each average value as the remaining amount of toner for each color.

  Waveforms W10, W20, W30, and W40 shown in FIGS. 4A to 4D are obtained by the sampling unit 101 for each color of magenta (M), cyan (C), yellow (Y), and black (Bk). The waveform of the average value of the output value V output is shown. Note that the sampling unit 101 is not limited to the average value, and the maximum value among the output values V sampled at the arrival of the sampling period Tmin (sampling period) within the period in which the stirring and conveying screw 615 rotates once is colored. It may be calculated every time, and the maximum value may be detected as the remaining amount of toner of each color.

  Next, a process for changing the sampling period of the remaining amount of toner for each color will be described. For example, the sampling period setting unit 102 maintains the first sampling period when the remaining amount of toner acquired by the sampling unit 101 exceeds a predetermined first threshold (for example, Vmin shown in FIG. 4). On the other hand, when the remaining amount of toner acquired by the sampling unit 101 is equal to or less than the first threshold, the first sampling period is changed to a second sampling period shorter than the first sampling period. The sampling period setting unit 102 performs the processing for each color of magenta (M), cyan (C), yellow (Y), and black (Bk).

  In this case, when the period during which the agitating and conveying screw 615 rotates once is divided into the plurality of sampling periods, for example, 20 sampling periods, the sampling period setting unit 102, for example, for each of the colors in every other sampling period The sampling period is set as the first sampling period. The sampling unit 101 samples the output value V from the toner remaining amount sensor 17 for each color in the first sampling period.

  Then, when the remaining amount of toner acquired by the sampling unit 101 is equal to or less than the first threshold, the sampling period setting unit 102, for example, in the sampling period of each color in all of the 20 sampling cycles. The sampling unit 101 sets a sampling period (that is, the sampling period becomes the second sampling period) so as to sample the output value V from the toner remaining amount sensor 17 of each color.

  The sampling period setting unit 102 maintains the first sampling period when the remaining amount of toner acquired by the sampling unit 101 is equal to or less than a predetermined second threshold (for example, Vmax shown in FIG. 4). When the remaining amount of toner sampled by the sampling unit 101 exceeds the second threshold, the first sampling period is changed to a third sampling period longer than the first sampling period. The sampling period setting unit 102 performs the processing for each color of magenta (M), cyan (C), yellow (Y), and black (Bk).

  Also in this case, similarly to the above, the sampling period in every other sampling period is set as the first sampling period, and the sampling period setting unit 102 causes the remaining amount of toner acquired by the sampling unit 101 to exceed the second threshold value. For example, for the 20 sampling periods, the sampling period of each color in every two sampling periods is set as the third sampling period.

  With reference to FIG. 6, a process for changing the sampling period of the remaining amount of toner of each color will be described. FIG. 6 is a flowchart illustrating an example of processing for changing the sampling period of the remaining amount of toner for each color.

  First, the control unit 100 controls the driver 700 to start rotational driving of the agitating and conveying screw 615 provided for each of the toner containers 61M, 61C, 61Y, and 61Bk (step S1).

  The sampling unit 101 starts sampling the output value from each toner remaining amount sensor 17 at the same timing as the start of rotational driving by the stirring and conveying screw 615 (step S2). At this time, each time the first sampling period for the respective colors of magenta (M), cyan (C), yellow (Y), and black (Bk) arrives, the sampling unit 101 detects the remaining toner amount sensor for each color. The output value V from 17 is sampled.

  The sampling period setting unit 102 determines whether or not the output value V of each color sampled by the sampling unit 101 exceeds the second threshold value (for example, Vmax shown in FIG. 4) (step S3). For example, the sampling period setting unit 102 determines for each color whether or not the average value obtained from the sampling unit 101 exceeds the second threshold value.

  When there is a color whose output value exceeds the second threshold (YES in step S3), the sampling period setting unit 102 changes the sampling period of the color to the third sampling period that is longer than the first sampling period. (Step S4). As a result, the color toner with a larger amount of remaining toner has a smaller number of times of sampling by the sampling unit 101, so that there is a margin in the remaining amount of toner and the toner container of a color that does not require frequent detection of the remaining amount of toner. Therefore, it is possible to refrain from detecting the remaining amount of toner, and it is possible to reduce unnecessary control and processing.

  When the output value V is less than or equal to the second threshold (NO in step S3), the sampling period setting unit 102 further determines that the output value V of each color sampled by the sampling unit 101 is the first threshold ( For example, it is determined whether or not it is equal to or lower than Vmin shown in FIG.

  When the output value V is equal to or less than the first threshold value (YES in step S5), the sampling period setting unit 102 changes the sampling period of the color to the second sampling period shorter than the first sampling period ( Step S6). As a result, the color toner having a smaller amount of toner has a higher number of times of sampling by the sampling unit 101, so that the detection accuracy of the remaining amount of toner can be improved.

  On the other hand, when the output value V is larger than the first threshold (NO in step S5), the sampling period setting unit 102 maintains the first sampling period without changing the sampling period of the color (step S7). .

  The processes in steps S1 to S7 are continued until the control unit 100 controls the driver 700 to stop the rotational drive of the stirring and conveying screw 615 provided for each of the toner containers 61M, 61C, 61Y, and 61Bk. (NO in step S8), the control unit 100 controls the driver 700 to end when the rotation of each stirring and conveying screw 615 is stopped (YES in step S8).

  As described above, in this embodiment, the sampling period setting unit 102 divides the period T into a plurality of sampling periods Tmin, and then divides the sampling period Tmin to separate the sampling periods TM, TC, TY, and TBk for each color. Therefore, the sampling periods TM, TC, TY, and TBk for all colors are ensured within the sampling period Tmin.

  On the other hand, in a general image forming apparatus that performs color printing, the sampling period for all colors of magenta (M), cyan (C), yellow (Y), and black (Bk) is the sampling period Tmin. Only one color is sampled within the sampling period Tmin. For example, the comparative example shown in FIG. 5B shows a case where the sampling period TM for magenta (M) is secured as the sampling period Tmin. In this case, for all the colors of magenta (M), cyan (C), yellow (Y), and black (Bk), the timer resources for four colors are consumed when sampling the output value from the toner remaining amount sensor. The

  In this respect, in this embodiment, the sampling unit 101 performs sampling for all the colors of magenta (M), cyan (C), yellow (Y), and black (Bk) within the sampling period Tmin. The unit 101 can sample the remaining amount of toner for four colors using a timer resource for one color used in a general image forming apparatus. Therefore, in the image forming apparatus 1 of the present embodiment, the consumption of timer resources can be reduced by three colors compared to a general image forming apparatus, and sampling for four colors can be performed. That is, in the image forming apparatus 1 according to the present embodiment, the sampling unit 101 can sample the output value from the remaining toner sensor 17 while reducing the consumption amount of the timer resource as compared with the conventional one.

  That is, according to the present embodiment, it is possible to detect the remaining amount of toner in each color toner container 61M, 61C, 61Y, 61Bk while reducing the increase in timer resources as compared with the prior art.

  Note that the configuration and processing shown in each of the above embodiments using FIGS. 1 to 6 are only one embodiment of the present invention, and the configuration and processing of the present invention are not limited to this.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Control unit 12 Image forming part 17 Toner remaining amount sensor 61C Toner container 61M Toner container 61Y Toner container 61Bk Toner container 70 Motor 100 Control part 101 Sampling part 102 Sampling period setting part 121 Photosensitive drum 122C Developing unit 122M Developing Unit 122Y Developing unit 122Bk Developing unit 615 Agitating and conveying screw 615A Rotating shaft 617 Toner supply port 700 Driver

Claims (3)

A plurality of storage containers each containing toner for replenishing the developing unit and having a toner replenishing port on one end side for replenishing the toner;
A stirring / conveying member that is rotatably provided to each of the plurality of storage containers and has a rotation shaft extending from the one end portion toward the other end portion and conveys the toner to the toner supply port while stirring the toner. When,
A rotation driving unit that is provided for each of the plurality of storage containers and that rotates the stirring and conveying member;
A remaining toner sensor that is provided for each of the plurality of storage containers and detects the remaining amount of the toner;
A sampling unit that samples an output value of the toner remaining amount sensor for each color when the rotation driving unit is rotating the stirring conveyance member;
The period in which the stirring and conveying member rotates once is divided into a plurality of predetermined sampling periods, the sampling period is further divided for each color, and the divided sections are sampled for each color by the sampling unit. And a sampling period setting unit that is set as
The image forming apparatus, wherein the sampling unit acquires the toner remaining amount from the toner remaining amount sensor of each color for each sampling period set by the sampling period setting unit. The sampling period setting unit, for each color,
When the remaining amount of toner acquired by the sampling unit exceeds a predetermined first threshold indicating a reduction in the remaining amount of toner, the sampling period is maintained,
The sampling period is changed to a second sampling period shorter than the sampling period when the remaining amount of toner acquired by the sampling unit is equal to or less than the first threshold. Image forming apparatus. The sampling period setting unit
When the remaining amount of toner acquired by the sampling unit exceeds a predetermined second threshold value that is greater than the first threshold value, the sampling period is set to a third sampling period that is longer than the sampling period. The image forming apparatus according to claim 2 to be changed.

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