JP7505311B2 - Image forming apparatus, drive control method and drive control program - Google Patents

Description

This invention relates to an image forming device, a drive control method, and a drive control program, and in particular to an image forming device that forms an image using toner, a drive control method executed in the image forming device, and a drive control program that causes a computer to execute the drive control method.

Image forming devices, such as MFPs (Multi Function Peripherals), form a toner image on an image carrier by developing an electrostatic latent image formed on the image carrier with toner, and then transfer the toner image to a recording medium such as paper to form an image on the paper. For this purpose, a toner container that contains toner is attached to the MFP. This toner container has a hollow cylindrical shape, and is attached to the MFP so that its longitudinal direction is horizontal. The toner container has a spiral protrusion on its inner wall, and by rotating the toner container around its rotation axis, the toner moves inside the toner container along the rotation axis and is discharged outside the toner container.

For example, Japanese Patent Application Laid-Open No. 2005-316034 describes a toner supply device that includes a toner bottle that stores toner, a drive motor that drives and rotates the toner bottle, a storage unit that stores toner dispensed by the rotation of the toner bottle, a piezoelectric sensor that measures the weight of the toner bottle, and a control unit, the toner bottle has a supply port through which toner is supplied to the storage unit, and the control unit controls the drive motor according to the detection result of the piezoelectric sensor to change the rotation speed of the toner bottle when supplying toner from the toner bottle to the storage unit.

The toner replenishing device described in JP 2005-316034 A is based on the premise that the fluidity of the toner is constant. For example, a wax layer is formed on the surface of the toner, but the adhesive force of the wax layer may increase due to changes in the environment. The amount of toner discharged from the toner bottle changes depending on the fluidity of the toner, but the effect of the toner fluidity on the amount of toner discharged is greater the smaller the amount of toner contained in the toner bottle. When the amount of toner contained in the toner bottle decreases, the toner may adhere to each other or to the inner wall of the toner storage container. For this reason, the toner replenishing device described in JP 2005-316034 A has a problem in that when the amount of toner contained in the toner bottle decreases, the appropriate amount of toner may not be discharged from the toner storage container.

JP 2005-316034 A

This invention has been made to solve the above-mentioned problems, and one of the objects of this invention is to provide an image forming device that can discharge an appropriate amount of toner from a toner storage container regardless of the amount of toner contained in the toner storage container.

Another object of the present invention is to provide a drive control method that can discharge an appropriate amount of toner from a toner storage container regardless of the amount of toner contained in the toner storage container.

Yet another object of the present invention is to provide a drive control program that can discharge an appropriate amount of toner from a toner storage container regardless of the amount of toner contained in the toner storage container.

In order to achieve the above-mentioned object, according to one aspect of the present invention, an image forming apparatus includes a toner storage container in which toner is stored, a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner outside the toner storage container, and a drive control means that controls the drive unit, wherein the drive control means drives the drive unit by a first drive method in a first period, and drives the drive unit by a second drive method in a second period after the first period, in which an external force applied to the toner storage container is different from that of the first drive method , and the absolute value of the angular acceleration of the toner storage container in the second drive method is greater than that of the first drive method .

According to this aspect, the drive unit is driven by a first drive method in a first period, and the drive unit is driven by a second drive method in which the external force applied to the toner storage container is different from that of the first drive method in a second period after the first period. Therefore, since the force applied to the toner stored in the toner storage container is different between the first period and the second period, the toner stored in the toner storage container can be discharged from the toner storage container more easily in the second period than in the first period. As a result, it is possible to provide an image forming device that can discharge an appropriate amount of toner from the toner storage container regardless of the amount of toner stored in the toner storage container.

Preferably, the second driving method differs from the first driving method in the external force applied to the toner storage container while the toner storage container rotates a predetermined amount of rotation during the second period.

In accordance with this aspect, since the external force applied to the toner storage container differs while the toner storage container rotates a predetermined amount, the magnitude of the force applied to the toner storage container can be made different between the first driving method and the second driving method.

Preferably, the second driving method involves a greater number of acceleration and deceleration operations in which the toner storage container accelerates and decelerates than the first driving method.

In accordance with this aspect, the second driving method has a greater number of acceleration and deceleration operations in which the toner storage container accelerates and decelerates than the first driving method, and therefore the force applied to the toner stored in the toner storage container fluctuates more frequently in the second driving method than in the first driving method. This makes it possible to reduce the degree to which the fluidity of the toner decreases during the second period.

According to another aspect of the present invention, an image forming apparatus includes a toner storage container in which toner is stored, a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner outside the toner storage container, and a drive control means that controls the drive unit, wherein the drive control means drives the drive unit with a first drive method in a first period, and drives the drive unit with a second drive method in a second period after the first period, in which an external force applied to the toner storage container is different from that of the first drive method, the drive unit includes a stepping motor as a drive source, and the second drive method has a smaller number of steps per unit rotation angle for driving the stepping motor than the first drive method.

In accordance with this aspect, the second driving method has a smaller number of steps per unit rotation angle for driving the stepping motor than the first driving method, so the amount of fluctuation in the force applied to the toner contained in the toner container is greater in the second driving method than in the first driving method. This makes it possible to reduce the degree to which the fluidity of the toner decreases during the second period.

According to another aspect of the present invention, an image forming apparatus includes a toner storage container in which toner is stored, a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container, a drive control unit that controls the drive unit, and a remaining amount prediction unit that predicts a remaining amount of toner in the toner storage container,
There are multiple toner storage containers, and the drive unit drives the multiple toner storage containers simultaneously. The drive control means drives the drive unit by a first drive method in a first period, and drives the drive unit by a second drive method in a second period after the first period in which an external force applied to the toner storage container is different from the first drive method. The drive control means determines that the period is the first period when the minimum value of the remaining toner amount predicted by the remaining amount prediction means for each of the multiple toner storage containers is greater than a remaining amount threshold, and determines that the period is the second period when the minimum value is equal to or less than the remaining amount threshold.

According to this aspect, when the minimum value of the remaining toner amount predicted for each of the multiple toner storage containers is greater than the remaining amount threshold, it is determined to be the first period, and when the minimum value is equal to or less than the remaining amount threshold, it is determined to be the second period. Therefore, even if the amount of toner stored in the multiple toner storage containers is different, the second period can be appropriately determined.

According to another aspect of the present invention, an image forming apparatus includes a toner storage container in which toner is stored, a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container, and a drive control means that controls the drive unit, wherein the drive control means drives the drive unit by a first drive method in a first period, and drives the drive unit by a second drive method in a second period after the first period in which an external force applied to the toner storage container is different from that of the first drive method, the second drive method including a first force-based drive method in which a maximum value of the force applied to the toner storage container by the drive unit is equal to or less than a maximum value of the force applied to the toner storage container by the drive unit in the first drive method, and a second force-based drive method in which a maximum value of the force applied to the toner storage container by the drive unit is greater than a maximum value of the force applied to the toner storage container by the drive unit in the first drive method, and when a load on the drive unit is greater than a load threshold value, the drive control means drives the drive unit by the first force-based drive method without driving the drive unit by the second force-based drive method in the second period.

According to this aspect, when the load on the drive unit is greater than the load threshold, the drive unit is driven in the second period by the first force-based drive method that is equal to or less than the maximum force that the drive unit applies to the toner storage container in the first drive method. This prevents the drive unit from becoming overloaded.

According to another aspect of the present invention, an image forming apparatus includes a toner storage container in which toner is stored, a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container, and a drive control means that controls the drive unit, the drive control means drives the drive unit by a first drive method in a first period, and drives the drive unit by a second drive method in a second period after the first period, the second drive method being different from the first drive method in that an external force applied to the toner storage container is different from that of the first drive method, the second drive method being a drive method in which the drive unit rotates the toner storage container by a predetermined rotation amount. The toner consumption predicting means predicts a toner consumption amount indicating an amount of toner consumed by the developing means, and the drive control means drives the drive unit by the second time reference drive method without driving the drive unit by the first time reference drive method during the second period when the toner consumption amount predicted by the consumption prediction means is equal to or greater than a consumption threshold value.

According to this aspect, when the toner consumption amount is equal to or greater than the consumption threshold, the drive unit is driven by the second time-based drive method in which the time it takes for the drive unit to rotate the toner container a predetermined amount of rotations is shorter than the time in the first drive method. Therefore, even when the toner consumption amount is large, an appropriate amount of toner can be discharged from the toner container.

According to another aspect of the present invention, an image forming apparatus includes a toner storage container in which toner is stored, a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner outside the toner storage container, and a drive control means that controls the drive unit, wherein the drive control means drives the drive unit with a first drive method during a first period, and drives the drive unit with a second drive method in a second period after the first period in which an external force applied to the toner storage container is different from that of the first drive method, the second drive method including a first sound-based drive method in which the volume of a sound generated while the toner storage container is rotated by the drive unit a predetermined amount is equal to or lower than that of the first drive method, and a second sound-based drive method in which the volume of a sound generated while the toner storage container is rotated by the drive unit a predetermined amount is higher than that of the first drive method, and the image forming apparatus includes a user detection means that detects a user present within a predetermined range from the apparatus, and when a user is detected by the user detection means, the drive control means drives the drive unit with the first sound-based drive method during the second period without driving the drive unit with the second sound-based drive method.

According to this aspect, when a user is present within a predetermined range of the device, the drive unit is driven by a first sound reference drive method in which the volume of the sound generated while the drive unit rotates the toner storage container a predetermined amount of rotation is equal to or lower than that of the first drive method. This makes it possible to prevent a user present within a predetermined range of the device from hearing a sound with a volume higher than the volume of the sound generated while the drive unit rotates the toner storage container a predetermined amount of rotation in the first drive method. This makes it possible to prevent a user present within a predetermined range of the device from hearing abnormal sounds.

Preferably, the toner storage device further includes a sub-hopper for receiving the toner discharged from the toner storage container, and a hopper remaining amount detection means for detecting the remaining amount of toner stored in the sub-hopper, and the drive control means drives the drive unit in response to the remaining amount of toner stored in the sub-hopper falling below a lower threshold value.

In this aspect, the drive unit is driven when the remaining amount of toner contained in the sub-hopper falls below the lower threshold, so that the sub-hopper can be maintained in a state where the toner contained therein is equal to or greater than the lower threshold.

Preferably, the device further includes a notification means for notifying the user while the drive unit is being driven using the second drive method.

In accordance with this aspect, the user is notified that the drive unit is being driven using the second drive method, which prevents the user from detecting a change in the sound generated by the drive unit and mistaking it for an error.

According to another aspect of the present invention, a drive control method is a drive control method executed in an image forming device including a toner storage container in which toner is stored and a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner outside the toner storage container, the drive control method including the steps of: driving the drive unit by a first drive method in a first period; and driving the drive unit by a second drive method in a second period after the first period, in which an external force applied to the toner storage container is different from that of the first drive method, and the second drive method has an absolute value of the angular acceleration of the toner storage container that is greater than that of the first drive method .

According to this aspect, it is possible to provide a drive control method capable of discharging an appropriate amount of toner from a toner storage container regardless of the amount of toner stored in the toner storage container.
According to another aspect of the present invention, a drive control method is a drive control method executed in an image forming device including a toner storage container in which toner is stored and a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container, the drive control method including the steps of driving the drive unit by a first drive method in a first period, and driving the drive unit by a second drive method in a second period after the first period, in which an external force applied to the toner storage container is different from that of the first drive method, the drive unit including a stepping motor as a drive source, and the second drive method having a smaller number of steps per unit rotation angle for driving the stepping motor than the first drive method.
According to another aspect of the present invention, a drive control method is a drive control method executed in an image forming apparatus including a toner storage container in which toner is stored and a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container, wherein the toner storage container is multiple, and the drive unit drives the multiple toner storage containers simultaneously, and includes a remaining amount prediction step of predicting a remaining amount of toner in the toner storage container, a step of driving the drive unit by a first drive method in a first period, a step of driving the drive unit by a second drive method in a second period after the first period, in which an external force applied to the toner storage container is different from the first drive method, and a step of determining that the period is a first period when a minimum value of the remaining amount of toner predicted in the remaining amount prediction step for each of the multiple toner storage containers is greater than a remaining amount threshold, and determining that the period is a second period when the minimum value is equal to or less than the remaining amount threshold.
According to another aspect of the present invention, a drive control method is a drive control method executed in an image forming apparatus including a toner storage container in which toner is stored and a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container, the drive control method including the steps of: driving the drive unit by a first drive method in a first period; and driving the drive unit by a second drive method in a second period after the first period, in which an external force applied to the toner storage container is different from that applied by the first drive method, the second drive method including a first force-based drive method in which a maximum value of the force applied by the drive unit to the toner storage container is equal to or less than a maximum value of the force applied by the drive unit to the toner storage container in the first drive method, and a second force-based drive method in which a maximum value of the force applied by the drive unit to the toner storage container is greater than a maximum value of the force applied by the drive unit to the toner storage container in the first drive method, and when a load on the drive unit is greater than a load threshold value, the drive unit includes the step of driving the drive unit by the first force-based drive method during the second period without driving the drive unit by the second force-based drive method.
According to another aspect of the present invention, a drive control method is a drive control method executed in an image forming apparatus including a toner storage container in which toner is stored, a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container, and a developing means that forms an image based on the toner discharged from the toner storage container, the drive control method including the steps of driving the drive unit by a first drive method in a first period, and driving the drive unit by a second drive method in a second period after the first period, the second drive method being different from the first drive method in which an external force applied to the toner storage container is different from that of the first drive method. the second driving method includes a first time reference driving method in which the time taken by the driving unit to rotate the toner storage container a predetermined amount of rotation is equal to or longer than the time in the first driving method, and a second time reference driving method in which the time is shorter than the time in the first driving method, and further includes a consumption prediction step of predicting a toner consumption amount indicating an amount of toner consumed by the developing means, and a step of driving the driving unit by the second time reference driving method without driving the driving unit by the first time reference driving method during the second period if the toner consumption amount predicted in the consumption prediction step is equal to or greater than a consumption threshold value.
According to another aspect of the present invention, a drive control method is a drive control method executed in an image forming device including a toner storage container in which toner is stored and a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container, the drive control method including a step of driving the drive unit by a first drive method in a first period, and a step of driving the drive unit by a second drive method in a second period after the first period, in which an external force applied to the toner storage container is different from that of the first drive method, the second drive method including a first sound-based drive method in which the volume of a sound generated while the toner storage container is rotated by the drive unit a predetermined amount of rotation is greater than that of the first drive method, and a second sound-based drive method that is equal to or less than the first drive method, and further including a user detection step of detecting a user present within a predetermined range from the device, and if a user is detected in the user detection step, a step of driving the drive unit by the second sound-based drive method without driving the drive unit by the first sound-based drive method during the second period.

According to another aspect of the present invention, a drive control program causes a computer to execute the drive control method described above.

In accordance with this aspect, it is possible to provide a drive control program that can discharge an appropriate amount of toner from a toner storage container regardless of the amount of toner contained in the toner storage container.

1 is a perspective view showing an external appearance of an MFP according to an embodiment of the present invention; FIG. 2 is a schematic cross-sectional view showing the internal configuration of the MFP. FIG. 2 is a perspective view showing the appearance of a toner bottle and a sub-hopper. FIG. 2 is a diagram showing the internal configuration of a toner bottle, a sub-hopper, and a developing unit. FIG. 2 is a block diagram showing an example of a hardware configuration of an MFP. FIG. 2 is a block diagram showing an example of functions of a CPU included in the MFP. 10 is a first diagram showing an example of the angular velocity of a toner bottle rotated by a first driving method. FIG. FIG. 11 is a first diagram showing an example of the angular velocity of the toner bottle rotated by the second driving method. FIG. 11 is a second diagram showing an example of the angular velocity of the toner bottle rotated by the second driving method. 10 is a flowchart showing an example of the flow of an image forming process. 10 is a flowchart showing an example of the flow of a drive control process.

Below, an embodiment of the present invention will be described with reference to the drawings. In the following description, identical parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

Fig. 1 is a perspective view showing the external appearance of an MFP according to one embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing the internal configuration of the MFP. With reference to Figs. 1 and 2, the MFP 100 functions as an image forming device and includes a document reading unit 130 for reading a document, an automatic document feeder 120 for transporting the document to the document reading unit 130, an image forming unit 140 for forming on paper or the like a still image that is read and output by the document reading unit 130, a paper feed unit 150 for supplying paper to the image forming unit 140, and an operation panel 160 as a user interface.

The automatic document feeder 120 separates one or more documents placed on the document table and conveys them one by one to the document reading unit 130. The document reading unit 130 exposes the image of the document set on the document glass 11 by the automatic document feeder 120 with an exposure lamp 13 attached to a slider 12 that moves below the document glass 11. The reflected light from the document is guided to a lens 16 by a mirror 14 and two reflecting mirrors 15 and 15A, and forms an image on a CCD (Charge Coupled Devices) sensor 18. The exposure lamp 13 and the mirror 14 are attached to the slider 12, which is moved by a scanner motor 17 in the direction of the arrow (sub-scanning direction) shown in the figure at a speed V according to the copying magnification. This allows the entire surface of the document set on the document glass 11 to be scanned. In addition, as the exposure lamp 13 and mirror 14 move, the two reflecting mirrors 15 and 15A move in the direction of the arrow in the figure at a speed of V/2. This ensures that the optical path length of the light irradiated onto the document by the exposure lamp 13, from when it is reflected by the document until it is imaged on the CCD sensor 18, is always constant.

The reflected light that forms an image on the CCD sensor 18 is converted into image data as an electrical signal within the CCD sensor 18 and sent to a main circuit (not shown). The main circuit performs A/D conversion processing, digital image processing, etc. on the received analog image data, and then outputs it to the image forming unit 140. The main circuit converts the image data into printing data in cyan (C), magenta (M), yellow (Y), and black (K), and outputs it to the image forming unit 140.

The image forming unit 140 has developing units 24Y, 24M, 24C, and 24K, and corresponding removable toner bottles 41Y, 41M, 41C, and 41K. The toner bottles 41Y, 41M, 41C, and 41K store yellow, magenta, cyan, and black toner, respectively. Here, "Y", "M", "C", and "K" represent yellow, magenta, cyan, and black, respectively. The toner in the toner bottles 41Y, 41M, 41C, and 41K is supplied to the developing units 24Y, 24M, 24C, and 24K, respectively, via sub-hoppers described below.

The image forming section 140 includes image forming units 20Y, 20M, 20C, and 20K for yellow, magenta, cyan, and black, respectively. An image is formed by driving at least one of the image forming units 20Y, 20M, 20C, and 20K. When all of the image forming units 20Y, 20M, 20C, and 20K are driven, a full-color image is formed. Print data for yellow, magenta, cyan, and black is input to the image forming units 20Y, 20M, 20C, and 20K, respectively. The only difference between the image forming units 20Y, 20M, 20C, and 20K is the color of the toner they handle, so here we will explain the image forming unit 20Y for forming a yellow image.

Image forming unit 20Y includes exposure head 21Y to which yellow printing data is input, photoconductor drum 23Y, electrostatic charger 22Y, developer 24Y, and transfer charger 25Y. Exposure head 21Y emits laser light in response to the received printing data (electrical signal). The emitted laser light is scanned one-dimensionally by a polygon mirror provided in exposure head 21Y, exposing photoconductor drum 23Y. The direction in which the photoconductor drum is scanned one-dimensionally is the main scanning direction.

The photoconductor drum 23Y is charged by the electrostatic charger 22Y, and then irradiated with laser light emitted by the exposure head 21Y. This forms an electrostatic latent image on the photoconductor drum 23Y. Next, the developer 24Y applies toner onto the electrostatic latent image to form a toner image. The toner image formed on the photoconductor drum 23Y is transferred onto the intermediate transfer belt 30 by the transfer charger 25Y.

Meanwhile, intermediate transfer belt 30 is suspended between drive roller 33C and roller 33A so as not to slacken. When drive roller 33C rotates counterclockwise in the figure, intermediate transfer belt 30 rotates counterclockwise in the figure at a predetermined speed. As intermediate transfer belt 30 rotates, roller 33A rotates counterclockwise.

As a result, image forming units 20Y, 20M, 20C, and 20K transfer toner images onto intermediate transfer belt 30 in sequence. The timing at which each of image forming units 20Y, 20M, 20C, and 20K transfers a toner image onto intermediate transfer belt 30 is adjusted by detecting a reference mark on intermediate transfer belt 30. As a result, yellow, magenta, cyan, and black toner images are superimposed on intermediate transfer belt 30.

Different sizes of paper are set in the paper feed cassettes 35, 35A, and 35B. The paper of the desired size is supplied to the conveying path by the paper feed rollers 36, 36A, and 36B attached to the paper feed cassettes 35, 35A, and 35B. The paper supplied to the conveying path is sent to the timing roller 31 by the conveying roller pair 37.

A timing sensor is installed to detect the reference mark on the intermediate transfer belt 30. When the timing sensor detects the reference mark on the intermediate transfer belt 30, the timing roller 31 supplies the paper to the intermediate transfer belt 30 in synchronization with the detection. The paper is pressed against the intermediate transfer belt 30 by the transfer roller 26, and the yellow, magenta, cyan, and black toner images formed in superimposition on the intermediate transfer belt 30 are transferred to the paper. A cleaner 28 is disposed on the outer periphery of the drive roller 33C. The cleaner 28 removes toner remaining on the intermediate transfer belt 30.

The paper with the transferred toner image is transported to the pair of fixing rollers 32 and heated by the pair of fixing rollers 32. This melts the toner and fixes it to the paper. The paper is then discharged to the paper output tray 39. Note that, although a tandem type MFP 100 equipped with image forming units 20Y, 20M, 20C, and 20K that form four color toners on the paper is described here, the MFP 100 may also adopt a four-cycle type in which the four color toners are transferred to the paper in sequence using a single photosensitive drum.

When forming a full-color image, the MFP 100 drives all of the image forming units 20Y, 20M, 20C, and 20K, but when forming a monochrome image, it drives one of the image forming units 20Y, 20M, 20C, and 20K. In addition, an image can be formed by combining two or more of the image forming units 20Y, 20M, 20C, and 20K.

Figure 3 is a perspective view showing the appearance of the toner bottle and sub-hopper. Referring to Figure 3, each of toner bottles 41Y, 41M, 41C, and 41K includes a bottle portion 411 that contains toner, and a cap portion 412 that is attached to one end of the bottle portion 411. A knob 413 is provided on the cap portion 412. With toner bottles 41Y, 41M, 41C, and 41K inserted into MFP 100, knob 413 is rotated a certain angle to fix cap portion 412 to MFP 100. Sub-hoppers 42Y, 42M, 42C, and 42K are provided integrally with toner bottles 41Y, 41M, 41C, and 41K, respectively. When toner bottles 41Y, 41M, 41C, and 41K are inserted into MFP 100, the caps 412 of toner bottles 41Y, 41M, 41C, and 41K are positioned above sub-hoppers 42Y, 42M, 42C, and 42K, respectively.

The sub-hoppers 42Y, 42M, 42C, and 42K have almost the same configuration, and the developers 24Y, 24M, 24C, and 24K have almost the same configuration. Here, the internal configurations of the toner bottle 41Y, the sub-hopper 42Y, and the developer 24Y are described as an example.

Figure 4 is a diagram showing the internal configuration of the toner bottle, sub-hopper, and developer. Referring to Figure 4, an opening 411a is provided at one end of the bottle portion 411, and a spiral protrusion is formed on the inner peripheral surface of the bottle portion 411. The cap portion 412 is attached to the bottle portion 411 so as to surround the periphery of the opening 411a. The cap portion 412 is formed with a supply port 412a that opens downward, and a shutter portion 415 is provided to be able to open and close the supply port 412a. The shutter portion 415 is linked to a knob 413 (Figure 3), and the shutter portion 415 is opened by rotating the knob 413. The bottle rotation mechanism 43 is connected to the other end of the bottle portion 411.

The bottle rotation mechanism 43 includes a stepping motor 43a, and the rotational force of the stepping motor 43a is transmitted to the toner bottle 41Y to rotate the toner bottle 41Y. In the bottle rotation mechanism 43, the stepping motor 43a is shared by the toner bottles 41Y, 41M, 41C, and 41K. The rotational force of the stepping motor 43a is transmitted to each of the toner bottles 41Y, 41M, 41C, and 41K via gears. Therefore, the toner bottles 41Y, 41M, 41C, and 41K rotate simultaneously in response to the driving of the stepping motor 43a. Note that in this embodiment, an example is shown in which the stepping motor 43a drives all of the toner bottles 41Y, 41M, 41C, and 41K simultaneously, but this configuration is not limited to this. The toner bottles 41Y, 41M, 41C, and 41K to be driven may be selected from among the toner bottles 41Y, 41M, 41C, and 41K depending on the direction of rotation of the stepping motor 43a. For example, when the stepping motor 43a rotates forward, the toner bottles 41Y and 41M rotate simultaneously but the toner bottles 41C and 41K do not rotate simultaneously, and when the stepping motor 43a rotates reversely, the toner bottles 41C and 41K rotate simultaneously but the toner bottles 41Y and 41M do not rotate simultaneously. Also, a stepping motor may be provided for each of the toner bottles 41Y, 41M, 41C, and 41K. In this case, each of the toner bottles 41Y, 41M, 41C, and 41K can rotate independently.

A supply port 422a is formed in the upper part of the sub-hopper 42Y so as to overlap with the supply port 412a of the toner bottle 41Y. The inside of the sub-hopper 42Y is divided into a storage section 422 and a conveying section 423 by a partition wall 421. A gap 421a is formed between one end of the partition wall 421 and the inner wall surface of the sub-hopper 42Y. The gap 421a is located above one end of the conveying section 423, and the storage section 422 communicates with the conveying section 423 via the gap 421a.

When the toner bottle 41Y is rotated by the bottle rotation mechanism 43, the toner in the bottle portion 411 moves forward along the spiral protrusion formed on the inner peripheral surface of the bottle portion 411 and flows out from the opening 411a. Furthermore, the toner that flows out from the opening 411a passes through the supply port 412a of the cap portion 412 and the supply port 422a of the sub hopper 42Y and falls into the storage portion 422 of the sub hopper 42Y.

The container 422 is provided with a float member 424 that swings around a horizontal axis. The inclination of the float member 424 changes depending on the amount of toner in the container 422. An empty sensor 427 is provided on the outer surface of the container 422. When the amount of toner in the container 422 is insufficient and the inclination of the float member 424 increases, the empty sensor 427 detects the object to be detected (e.g., a magnet) attached to the float member 424.

The conveying section 423 is provided with a spiral supply roller 425. The supply roller 425 is connected to a sub-hopper driving mechanism 426. The sub-hopper driving mechanism 426 includes a stepping motor 426a, and the rotational force of the stepping motor 426a is transmitted to the supply roller 425 to rotate the supply roller 425. The other end of the conveying section 423 (the end opposite the gap 421a) is connected to the developing device 24Y via a communication section 428. When the supply roller 425 is rotated by the sub-hopper driving mechanism 426, the toner is conveyed from one end of the conveying section 423 to the other end and supplied to the developing device 24Y through the communication section 428. Therefore, the amount of toner supplied to the developing device 24Y can be adjusted by the rotation speed of the supply roller 425. In addition, the relationship between the rotation speed of the supply roller 425 and the amount of toner supplied to the developing device 24Y is proportional if the state of the toner stored in the storage section 422 is normal. The state of the toner stored in the storage section 422 includes the amount of toner stored in the storage section 422 and the fluidity of the toner stored in the storage section 422. Therefore, by normalizing the state of the toner stored in the storage section 422 and measuring the number of rotations of the supply roller 425 and the amount of toner supplied to the developing device 24Y, the number of rotations of the supply roller 425 required to supply a unit amount of toner to the developing device 24Y can be determined as the reference drive amount.

The developing device 24Y includes a storage section 241, transport rollers 242 and 243, and a developing roller 244. The toner supplied from the sub-hopper 42Y is stored in the storage section 241. The transport rollers 242 and 243 are arranged in the storage section 241, and the developing roller 244 is arranged so as to be partially exposed from the storage section 241. The transport rollers 242 and 243 are rotated by a motor (not shown), respectively, to transport the toner in the storage section 241 toward the developing roller 244. The outer circumferential surface of the developing roller 244 faces the outer circumferential surface of the photosensitive drum 23Y. The storage section 241 contains a carrier. The carrier is magnetic, but the toner is not magnetic. While the toner and carrier are transported by the transport rollers 242 and 243, the toner adheres to the carrier due to static electricity. The developing roller 244 has a magnet fixedly arranged in a rotatable sleeve. The developing roller 244 is rotated by a motor (not shown), and magnetically carries and transports the carrier to which the toner is attached, causing the toner to adhere to the electrostatic latent image formed on the photoconductor drum 23Y. Here, the toner concentration is the ratio of the toner to the toner and carrier stored in the storage section 241.

The bias voltage applied to the developing roller 244 is determined on the assumption that the toner concentration is within a specified range. Therefore, if the toner concentration deviates from the specified range, the print quality becomes unstable. For example, a phenomenon called fogging may occur, in which toner adheres to areas other than the electrostatic latent image formed on the photoconductor drum 23Y, or a phenomenon called carrier adhesion may occur, in which carrier adheres to the photoconductor drum 23Y. If the carrier adhesion phenomenon occurs, it may damage the photoconductor drum 23Y, shorten the life of the parts, and may cause the MFP main body to break down. Therefore, it is necessary to keep the toner concentration in the storage unit 241 within a specified range.

The density detection sensor 27Y is disposed downstream of the developing roller 244 of the photoconductor drum 23Y. The density detection sensor 27Y is composed of a light-emitting diode and a phototransistor, and is disposed opposite the surface of the photoconductor drum 23Y. The density detection sensor 27Y receives light emitted from the light-emitting diode and reflected by the photoconductor drum 23Y with a phototransistor, and outputs an electronic signal that is photoelectrically converted by the phototransistor. The electrical signal output by the density detection sensor 27Y varies depending on the amount of toner attached to the photoconductor drum 23Y, so the amount of toner attached to the photoconductor drum 23Y can be detected from this electrical signal. In this embodiment, the amount of toner attached to the photoconductor drum 23Y is measured, but the amount of toner attached to the intermediate transfer belt 30 may be measured. When measuring the amount of toner attached to the intermediate transfer belt 30, one density detection sensor may be provided for each of the image forming units 20Y, 20M, 20C, and 20K.

Figure 5 is a block diagram showing an example of the hardware configuration of an MFP. Referring to Figure 5, the main circuit 110 of the MFP 100 includes a CPU 111, a communication interface (I/F) unit 112, a ROM 113, a RAM 114, a hard disk drive (HDD) 116 as a large-capacity storage device, a facsimile unit 117, a motion sensor 118, and an external storage device 119 to which a CD-ROM (Compact Disk ROM) 119A is attached. The CPU 111 is also connected to the automatic document feeder 120, the document reading unit 130, the image forming unit 140, the paper feed unit 150, and the operation panel 160, and controls the entire MFP 100.

ROM 113 stores the programs executed by CPU 111 or data required to execute the programs. RAM 114 is used as a working area when CPU 111 executes the programs.

Operation panel 160 is provided on the top surface of MFP 100 (see FIG. 1) and includes a display unit 161 and an operation unit 163. Display unit 161 is a display device such as a liquid crystal display (LCD) or an organic ELD (Electroluminescence Display), and displays an instruction menu for the user and information related to acquired image data. Operation unit 163 has a number of keys and accepts input of various instructions, letters, numbers, and other data by user operation corresponding to the keys. Operation unit 163 further includes a touch panel provided on display unit 161.

The communication I/F unit 112 is an interface for connecting the MFP 100 to a network. The CPU 111 communicates with a computer connected to the network via the communication I/F unit 112 to send and receive data. The communication I/F unit 112 can also communicate with a computer connected to the Internet via the network.

The human sensor 118 detects a person within a predetermined range from the MFP 100 and outputs the fact that a person has been detected to the CPU 111. In this embodiment, an infrared sensor is used as the human sensor 118. Note that the human sensor 118 only needs to be able to detect the presence of a person within a predetermined range from the MFP 100, and a pyroelectric sensor, a temperature sensor, an ultrasonic sensor, a laser Doppler sensor, a sound collection microphone, or a pressure sensor may be used instead of an infrared sensor. When a pressure sensor is used as the human sensor 118, a mat with a built-in pressure sensor is placed on the floor within a predetermined range from the MFP 100, and the presence of a person within a predetermined range from the MFP 100 is detected by detecting the pressure points caused by walking on the mat. When a sound collection microphone is used as the human sensor 118, a change in the volume of footsteps is detected from the sound collected by the sound collection microphone, and a person approaching the MFP 100 is detected.

Facsimile unit 117 is connected to the public switched telephone network (PSTN) and transmits facsimile data to the PSTN or receives facsimile data from the PSTN. Facsimile unit 117 stores the received facsimile data in HDD 116 or outputs it to image forming unit 140. Image forming unit 140 prints the facsimile data received by facsimile unit 117 on paper. Facsimile unit 117 also converts data stored in HDD 116 into facsimile data and transmits it to a facsimile device connected to the PSTN.

CD-ROM 119A is attached to external storage device 119. CPU 111 can access CD-ROM 119A via external storage device 119. CPU 111 loads a program recorded on CD-ROM 119A attached to external storage device 119 into RAM 114 and executes it. Note that the program executed by CPU 111 is not limited to the program recorded on CD-ROM 119A, and a program stored in HDD 116 may be loaded into RAM 114 and executed. In this case, another computer connected to the network may rewrite the program stored in HDD 116 of MFP 100, or may add and write a new program. Furthermore, MFP 100 may download a program from another computer connected to the network and store the program in HDD 116. The program here includes not only a program that CPU 111 can directly execute, but also a source program, a compressed program, an encrypted program, and the like.

The medium for storing the programs executed by CPU 111 is not limited to CD-ROM 119A, but may be an optical disc (MO (Magnetic Optical Disc)/MD (Mini Disc)/DVD (Digital Versatile Disc)), IC card, optical card, mask ROM, EPROM (Erasable Programmable ROM), or other semiconductor memory.

Figure 6 is a block diagram showing an example of functions of a CPU included in an MFP. The functions shown in Figure 6 are functions formed in CPU 111 included in MFP 100 by CPU 111 executing a toner supply program stored in CD-ROM 119A. Referring to Figure 6, CPU 111 included in MFP 100 includes a drive control unit 51, a remaining amount prediction unit 53 that predicts the remaining amount of toner contained in each of toner bottles 41Y, 41M, 41C, and 41K as the remaining toner amount, a consumption amount prediction unit 55, a hopper drive unit 57, an empty determination unit 59, a nearby user determination unit 61, and a notification unit 63.

The remaining amount prediction unit 53 predicts the remaining amount of toner contained in each of the toner bottles 41Y, 41M, 41C, and 41K. The remaining amount prediction unit 53 outputs the remaining amount of each of the toner bottles 41Y, 41M, 41C, and 41K to the drive control unit 51. The remaining amount prediction unit 53 predicts the remaining amount of toner based on the rotation number of each of the toner bottles 41Y, 41M, 41C, and 41K. Here, the toner bottle 41Y will be described. The amount of toner contained in the toner bottle 41Y before the toner bottle 41Y is attached to the MFP 100 is predetermined. In addition, the amount of toner discharged from the toner bottle 41Y during one rotation of the toner bottle 41Y after the toner bottle 41Y is attached to the MFP 100 is predetermined. The remaining amount prediction unit 53 stores the number of rotations since the toner bottle 41Y is attached to the MFP 100, and calculates the remaining amount of the toner bottle 41Y based on the number of rotations. Furthermore, the remaining amount prediction unit 53 calculates the number of rotations of the toner bottle 41Y since it was attached to the MFP 100 based on the number of rotations of the stepping motor 43a. Note that, in the present embodiment, an example is shown in which the remaining amount prediction unit 53 predicts the remaining amount of toner based on the number of rotations of the toner bottle 41Y, but this configuration is not limiting. For example, the remaining amount prediction unit 53 may measure the weight of the toner bottle 41Y and calculate the remaining amount from the measured weight. Furthermore, the remaining amount prediction unit 53 may calculate the remaining amount of the toner bottle 41Y based on the consumption amount of yellow toner predicted by the consumption amount prediction unit 55 described later.

The consumption prediction unit 55 predicts the toner consumption based on the image data that is the subject of image formation. As described above, the cyan print data is output to the image forming unit 20C, the magenta print data is output to the image forming unit 20M, the yellow print data is output to the image forming unit 20Y, and the black print data is output to the image forming unit 20K. Each of the image forming units 20Y, 20M, 20C, and 20K forms an image on paper based on the corresponding print data. For example, the image forming unit 20Y forms an image on paper supplied from the paper feed unit 150 with the toner stored in the storage unit 241 based on the yellow print data.

Therefore, the consumption prediction unit 55 converts the image data consisting of RGB into printing data for cyan (C), magenta (M), yellow (Y), and black (K). Then, the consumption prediction unit 55 predicts the amount of toner (hereinafter referred to as "toner consumption amount") for each of cyan, magenta, yellow, and black consumed by the image forming unit 140 based on the printing data for each of cyan, magenta, yellow, and black. The consumption prediction unit 55 outputs the toner consumption amount for each of cyan, magenta, yellow, and black to the drive control unit 51 and the hopper drive unit 57. The control of the image forming units 20Y, 20M, 20C, and 20K by the CPU 111 is the same except for the printing data, so in the following explanation, unless otherwise specified, the control of the image forming unit 20Y by the CPU 111 will be explained.

The consumption prediction unit 55 predicts the amount of yellow toner consumed by the image forming unit 20Y based on the yellow printing data, and outputs the predicted toner consumption to the drive control unit 51 and the hopper driving unit 57. The consumption prediction unit 55 calculates the amount of toner consumption from the pixel values of the yellow printing data. The toner amount can be calculated from the pixel values of the printing data using a table in which a previously measured amount of toner is associated with each of a plurality of pixel values. A formula that defines the relationship between the pixel value and the amount of toner may also be prepared in advance.

The hopper drive unit 57 controls the sub hopper drive mechanism 426 to supply the toner stored in the storage section 422 of the sub hopper 42Y to the developing device 24Y. Specifically, the hopper drive unit 57 controls the stepping motor 426a to adjust the amount of toner supplied from the storage section 422 of the sub hopper 42Y to the developing device 24Y.

The hopper drive unit 57 determines the drive amount of the sub-hopper drive mechanism 426 based on the toner consumption amount input from the consumption amount prediction unit 55. Specifically, the hopper drive unit 57 determines the rotation speed of the stepping motor 426a from the toner consumption amount and the reference drive amount so that the same amount of toner as the toner consumption amount is supplied from the sub-hopper 42Y to the developing device 24Y. The hopper drive unit 57 determines the drive amount each time the total of the toner consumption amounts input from the consumption amount prediction unit 55 becomes equal to or greater than the upper limit value for refilling. The upper limit value for refilling is a predetermined value. The hopper drive unit 57 determines the drive amount when the total of the toner consumption amounts input from the consumption amount prediction unit 55 after determining the drive amount becomes equal to or greater than the upper limit value for refilling. The hopper drive unit 57 may determine the drive amount each time the toner consumption amount is input from the consumption amount prediction unit 55.

When the empty sensor 427 detects the object to be detected attached to the float member 424, the hopper drive unit 57 outputs a drive command to the drive control unit 51.

The nearby user determination unit 61 controls the human presence sensor 118 to detect a user present within a predetermined distance from the MFP 100. In response to the detection of a person by the human presence sensor 118, the nearby user determination unit 61 outputs a detection signal indicating that a person has been detected to the drive control unit 51. The nearby user determination unit 61 outputs the detection signal while a person is being detected by the human presence sensor 118.

In response to a drive command input from the hopper drive unit 57, the drive control unit 51 controls the bottle rotation mechanism 43 to supply the toner stored in the toner bottle 41Y to the sub-hopper 42Y. Specifically, the drive control unit 51 controls the stepping motor 43a to supply the toner stored in the toner bottle 41Y to the storage unit 422 of the sub-hopper 42Y.

The drive control unit 51 includes a period determination unit 71, a first drive unit 73, a second drive unit 75, a remaining toner amount determination unit 77, and a consumed toner amount determination unit 70. The period determination unit 71 determines whether the current date and time is in the first period or the second period following the first period, based on the remaining toner amount input from the remaining toner amount prediction unit 53. If the period determination unit 71 determines that the current date and time is in the first period, it outputs a first period signal to the first drive unit 73, and if it determines that the current date and time is in the second period, it outputs a second period signal to the second drive unit 75.

The remaining toner amount of each of the toner bottles 41Y, 41M, 41C, and 41K is input to the period determination unit 71 from the remaining amount prediction unit 53. The period determination unit 71 determines that the period is the first period when the minimum value of the remaining toner amount of each of the toner bottles 41Y, 41M, 41C, and 41K is greater than the remaining amount threshold, and determines that the period is the second period when the minimum value of the remaining toner amount of each of the toner bottles 41Y, 41M, 41C, and 41K is equal to or less than the remaining amount threshold. In other words, the period determination unit 71 determines that the period is the first period when the remaining toner amount of all of the toner bottles 41Y, 41M, 41C, and 41K is greater than the remaining amount threshold, and determines that the period is the second period when the remaining toner amount of at least one of the toner bottles 41Y, 41M, 41C, and 41K is equal to or less than the remaining amount threshold.

The amount of toner discharged from each of the toner bottles 41Y, 41M, 41C, and 41K is different for each of the toner bottles 41Y, 41M, 41C, and 41K. Therefore, the amount of remaining toner in each of the toner bottles 41Y, 41M, 41C, and 41K is different for each of the toner bottles 41Y, 41M, 41C, and 41K. When the toner bottles 41Y, 41M, 41C, and 41K are attached to the MFP 100, the amount of remaining toner in each of the toner bottles 41Y, 41M, 41C, and 41K is greater than the remaining amount threshold. During the process in which an image is formed in the MFP 100 and toner is consumed, the period until the amount of remaining toner in the toner bottle with the largest amount of discharged toner among the toner bottles 41Y, 41M, 41C, and 41K becomes equal to or less than the remaining amount threshold is determined as the first period, and when the amount of remaining toner in the toner bottle with the largest amount of discharged toner becomes equal to or less than the remaining amount threshold is determined as the second period.

The remaining toner amount determination unit 77 determines whether the load on the stepping motor 43a is equal to or greater than a predetermined load threshold. The remaining toner amount determination unit 77 receives the remaining toner amount of each of the toner bottles 41Y, 41M, 41C, and 41K from the remaining amount prediction unit 53. The remaining toner amount determination unit 77 determines that the load on the stepping motor 43a is equal to or greater than the load threshold when at least one of the remaining toner amounts of each of the toner bottles 41Y, 41M, 41C, and 41K is equal to or greater than the remaining amount threshold. The load on the stepping motor 43a is proportional to the remaining toner amount of each of the toner bottles 41Y, 41M, 41C, and 41K. The remaining toner amount determination unit 77 may determine whether the load on the stepping motor 43a is equal to or greater than the load threshold by calculating the load on the stepping motor 43a from the sum of the remaining toner amounts of each of the toner bottles 41Y, 41M, 41C, and 41K.

The toner consumption amount determination unit 79 determines whether at least one of the toner consumption amounts for cyan, magenta, yellow, and black predicted by the consumption amount prediction unit 55 is equal to or greater than a consumption threshold. The toner consumption amount determination unit 79 outputs the determination result to the second drive unit 75.

The first drive unit 73 drives the stepping motor 43a by the first drive method in response to a drive command input from the hopper drive unit 57 while the first period signal is being input from the period determination unit 71. The second drive unit 75 drives the stepping motor 43a by the second drive method in response to a drive command input from the hopper drive unit 57 while the second period signal is being input from the period determination unit 71. The second drive method differs from the first drive method in the external forces applied to the toner bottles 41Y, 41M, 41C, and 41K while they rotate a predetermined amount. Since the external forces applied to the toner bottles 41Y, 41M, 41C, and 41K are the same, the following description will be given using toner bottle 41Y as an example.

The first drive unit 73 and the second drive unit 75 each control the stepping motor 43a to accelerate the toner bottle 41Y from a non-rotating state until it reaches a predetermined angular velocity V1, rotate the toner bottle 41Y at angular velocity V1 after it has reached angular velocity V1, and then decelerate the toner bottle 41Y until it no longer rotates.

The second driving method includes a first force-based driving method in which the maximum value of the force that the stepping motor 43a applies to the toner bottle 41Y is equal to or less than the maximum value of the force that the stepping motor 43a applies to the toner bottle 41Y in the first driving method, and a second force-based driving method in which the maximum value of the force that the stepping motor 43a applies to the toner bottle 41Y is greater than the maximum value of the force that the stepping motor 43a applies to the toner bottle 41Y in the first driving method. The maximum value of the force that the stepping motor 43a applies to the toner bottle 41Y is smaller in the first force-based driving method than in the second force-based driving method.

The second driving method includes a first time-based driving method in which the time taken by the stepping motor 43a to rotate the toner bottle 41Y by a predetermined rotation amount R1 is equal to or longer than the time taken by the first driving method, and a second time-based driving method in which the time taken by the stepping motor 43a to rotate the toner bottle 41Y by a predetermined rotation amount R1 is shorter than the time taken by the first driving method. The time taken by the stepping motor 43a to rotate the toner bottle 41Y by a predetermined rotation amount R1 in the first time-based driving method is longer than the time taken by the second time-based driving method.

The second driving method includes a first sound-based driving method in which the volume of the sound generated while the stepping motor 43a rotates the toner bottle 41Y by a predetermined rotation amount R1 is equal to or lower than the volume in the first driving method, and a second sound-based driving method in which the volume is higher than the volume in the first driving method. The volume of the sound generated while the stepping motor 43a rotates the toner bottle 41Y by a predetermined rotation amount R1 is lower in the first time-based driving method than in the second time-based driving method.

Figure 7 is a first diagram showing an example of the angular velocity of a toner bottle rotating in a first driving method. Figure 8 is a first diagram showing an example of the angular velocity of a toner bottle rotating in a second driving method. In Figures 7 and 8, an example is shown in which the toner bottle 41Y is rotated by a rotation amount R1. Referring to Figure 7, the first driving unit 73 accelerates the toner bottle 41Y at a first angular acceleration A1 from a state in which the toner bottle 41Y is not rotating until the angular velocity reaches V1, rotates the toner bottle 41Y at the angular velocity V1 after the angular velocity reaches V1, and then decelerates the toner bottle 41Y at a second angular acceleration A2 until the toner bottle 41Y stops rotating. The time T1 from when the rotation of the toner bottle 41Y starts to when it ends is determined by the rotation amount R1 of the toner bottle 41Y.

Referring to FIG. 8, the second drive unit 75 accelerates the toner bottle 41Y at a third angular acceleration A3 from a state in which the toner bottle 41Y is not rotating until the angular velocity reaches V1, rotates the toner bottle 41Y at the angular velocity V1 after the angular velocity reaches V1, and then decelerates the toner bottle 41Y at a fourth angular acceleration A4 until the toner bottle 41Y no longer rotates. The third angular acceleration A3 is greater than the first angular acceleration A1, and the absolute value of the fourth angular acceleration A4 is greater than the absolute value of the second angular acceleration A2. The absolute values of the first angular acceleration A1 and the second angular acceleration A2 may be the same or different. Furthermore, the absolute values of the third angular acceleration A3 and the fourth angular acceleration A4 may be the same or different.

Therefore, in the second driving method, which increases the angular acceleration more than the first driving method, the maximum value of the force that the second driving unit 75 applies to the toner bottle 41Y is greater than the maximum value of the force that the first driving unit 73 applies to the toner bottle 41Y. Therefore, the second driving method, which increases the angular acceleration more than the first driving method, is the second force-based driving method.

In addition, the greater the force that the toner bottle 41Y receives, the louder the sound generated by the bottle rotation mechanism 43 becomes. For this reason, the second driving method, which increases the angular acceleration more than the first driving method, is the first sound-based driving method.

The time T2 from when the rotation of the toner bottle 41Y starts to when it ends is determined by the amount of rotation R1 of the toner bottle 41Y. Time T2 is shorter than time T1. Therefore, the second driving method, which increases the angular acceleration more than the first driving method, is the second time-based driving method.

The first drive unit 73 drives the stepping motor 43a with a first excitation method, and the second drive unit 75 drives the stepping motor 43a with a second excitation method. The second excitation method has fewer steps per unit rotation angle than the first excitation method. Specifically, the first excitation method is W1-2 phase, and the second excitation method is 1-2 phase. Since the number of steps per unit rotation angle is greater in the first excitation method than in the second excitation method, the rotation of the stepping motor 43a is smoother in the first excitation method than in the second excitation method. When the stepping motor 43a is driven with the second excitation method, the rotation of the toner bottle 41Y is not as smooth as when the stepping motor 43a is driven with the second excitation method, and the fluctuation in the force that the toner bottle 41Y receives from the stepping motor 43a increases. The greater the fluctuation in the force that toner bottle 41Y receives, the louder the sound generated by the bottle rotation mechanism 43. For this reason, the second driving method, which differs from the first driving method in the excitation method, is the first sound-based driving method.

When the stepping motor 43a is driven with the second excitation method at the same angular acceleration as when the stepping motor 43a is driven with the first excitation method, the time from when the toner bottle 41Y starts to rotate to when the rotation of the rotation amount R1 ends is the same as when the toner bottle 41Y is rotated by the rotation amount R1 with the first driving method. Therefore, the second driving method, which differs from the first driving method in terms of the excitation method, is the first time-based driving method.

When the stepping motor 43a is driven with the second excitation method at the same angular acceleration as that when the stepping motor 43a is driven with the first excitation method, the maximum value of the force that the second drive unit 75 applies to the toner bottle 41Y is the same as the maximum value of the force that the first drive unit 73 applies to the toner bottle 41Y. Therefore, the second drive method, which differs from the first drive method in excitation method, is the first force-based drive method.

Figure 9 is a second diagram showing an example of the angular velocity of the toner bottle rotating by the second driving method. In Figure 9, an example is shown in which the toner bottle 41Y is rotated by the rotation amount R1. Referring to Figure 9, the difference from Figure 7 is that the number of times the toner bottle 41Y is accelerated and decelerated is large. Specifically, the second driving unit 75 accelerates the toner bottle 41Y at the first angular acceleration A1 from a state in which the toner bottle 41Y is not rotating until the angular velocity becomes V1, then decelerates the toner bottle 41Y at the second angular acceleration A2 until the toner bottle 41Y no longer rotates, and further accelerates the toner bottle 41Y at the first angular acceleration A1 from a state in which the toner bottle 41Y is not rotating until the angular velocity becomes V1, rotates the toner bottle 41Y at the angular velocity V1 after the angular velocity becomes V1, and then decelerates the toner bottle 41Y at the second angular acceleration A2 until the toner bottle 41Y no longer rotates. In this way, the toner bottle 41Y is accelerated and decelerated twice, so the number of times that the force applied to the toner bottle 41Y by the second drive unit 75 changes is greater than the number of times that the force applied to the toner bottle 41Y by the first drive unit 73 changes.

The time T3 from when the rotation of the toner bottle 41Y starts to when it ends is determined by the amount of rotation R1 of the toner bottle 41Y. Time T3 is greater than time T1. Therefore, the second driving method, which differs from the first driving method in the number of accelerations and decelerations, is the first time-based driving method.

Because the first angular acceleration during acceleration and the second angular acceleration during deceleration are the same in the first and second driving methods, the maximum value of the force that the second driving unit 75 applies to the toner bottle 41Y is the same as the maximum value of the force that the first driving unit 73 applies to the toner bottle 41Y. Therefore, the second driving method, which has more accelerations and decelerations than the first driving method, is the first force-based driving method and also the second sound-based driving method.

Returning to FIG. 6, when the remaining toner amount determination unit 77 determines that the load on the stepping motor 43a is equal to or greater than the load threshold, the second drive unit 75 drives the stepping motor 43a using the first force-based drive method rather than the second force-based drive method. In the first force-based drive method, the maximum value of the force that the stepping motor 43a applies to the toner bottle 41Y is smaller than in the second force-based drive method, so that when the load on the stepping motor 43a is equal to or greater than the load threshold, the maximum value of the force that the stepping motor 43a applies to the toner bottle 41Y is reduced, preventing the bottle rotation mechanism 43 including the stepping motor 43a from being overloaded and from being damaged.

Furthermore, when the toner consumption amount determination unit 79 determines that at least one of the toner consumption amounts for cyan, magenta, yellow, and black is equal to or greater than the consumption threshold, the second drive unit 75 drives the stepping motor 43a using the second time-based drive method instead of the first time-based drive method. In the second time-based drive method, the time required to rotate the toner bottle 41Y by a predetermined rotation amount R1 is shorter than the time required in the first time-based drive method, so that an appropriate amount of toner can be supplied to the sub-hopper 42Y even when the toner consumption amount is large.

The second drive unit 75 drives the stepping motor 43a using the second sound reference drive method instead of the first sound reference drive method while a detection signal is being input from the nearby user determination unit 61. The volume of the sound generated by the bottle rotation mechanism 43 is louder in the first sound reference drive method than in the first drive method and is lower in the second sound reference drive method than in the first drive method, so that the volume of the sound heard by a user within a predetermined distance from the MFP 100 can be prevented from being louder than the sound heard during the first period.

The notification unit 63 notifies the user while the second drive unit 75 is driving the stepping motor 43a. For example, the notification unit 63 displays a message on the display unit 161 indicating that the toner bottles 41Y, 41M, 41C, and 41K are being rotated using the second drive method during the second period. Also, an image indicating that the toner bottles 41Y, 41M, 41C, and 41K are being rotated using the second drive method during the second period may be displayed on the display unit 161.

The empty determination unit 59 detects that the toner bottle 41Y is empty when the empty sensor 427 detects the detection object attached to the float member 424 after outputting a drive command to the drive control unit 51 and completing control of the bottle rotation mechanism 43 by the drive control unit 51. If the amount of toner contained in the sub hopper 42Y does not increase even when the drive control unit 51 controls the bottle rotation mechanism 43, the amount of toner supplied from the toner bottle 41Y to the sub hopper 42Y is decreasing, so when the amount of toner supplied from the toner bottle 41Y to the sub hopper 42Y becomes equal to or less than a predetermined amount, the empty determination unit 59 notifies the user when it determines that the toner bottle 41Y is empty. For example, the empty determination unit 59 displays an image or message indicating that the toner bottle 41Y is empty on the display unit 161.

Figure 10 is a flow chart showing an example of the flow of image formation processing. The image formation processing is a process that is executed by CPU 111 of MFP 100 as CPU 111 executes an image formation program stored in CD-ROM 119A. Referring to Figure 10, CPU 111 determines whether or not a job has been accepted (step S01). The process goes into a standby state until a job is accepted (NO in step S01), and if the job has been accepted (YES in step S01), the process proceeds to step S02.

In step S02, the job is executed and image formation processing begins. Then, it is determined whether the remaining amount of toner in any of the sub-hoppers 42Y, 42M, 42C, and 42K is below the lower threshold (step S03). If the remaining amount of toner in any of the sub-hoppers 42Y, 42M, 42C, and 42K is below the lower threshold, processing proceeds to step S04, but if not, processing proceeds to step S12. Here, an example is described in which the remaining amount of toner in sub-hopper 42Y is below the lower threshold. In step S12, it is determined whether image formation has ended. If image formation has not ended, processing returns to step S03, but if image formation has ended, processing ends.

In step S04, the drive control process is executed, and the process proceeds to step S05. The drive control process will be described in detail later, but it is a process for driving the bottle rotation mechanism 43 to rotate the toner bottles 41Y, 41M, 41C, and 41K. As a result, toner is supplied from the toner bottles 41Y, 41M, 41C, and 41K to the sub-hoppers 42Y, 42M, 42C, and 42K, respectively.

In step S05, it is determined whether the remaining amounts of all of the sub-hoppers 42Y, 42M, 42C, and 42K are equal to or greater than the lower threshold. If the remaining amounts of all of the sub-hoppers 42Y, 42M, 42C, and 42K are equal to or greater than the lower threshold, the process proceeds to step S12; otherwise, the process proceeds to step S06. In step S06, the variable i is incremented and the process proceeds to step S07. The variable i is a value that determines the number of times the drive control process in step S04 is executed, and is initially set to "1" before step S06 is executed for the first time.

In step S07, it is determined whether the variable i is equal to or greater than the threshold value TH1. If the variable i is equal to or greater than the threshold value TH1, the process proceeds to step S08. If not, the process returns to step S04. The threshold value TH1 determines the upper limit of the number of times the drive control process is repeatedly executed. In step S08, an empty error is notified, and the process proceeds to step S09. The empty error indicates that the toner bottle 41Y corresponding to the sub-hopper 42Y, which is determined in step S03 to have a toner remaining amount equal to or less than the lower threshold, among the toner bottles 41Y, 41M, 41C, and 41K, is empty. For example, a message indicating that the toner bottle 41Y is empty and prompting replacement is displayed on the display unit 161. This allows the user to perform the task of replacing the toner bottle 41Y with a new toner bottle. After replacing the toner bottle 41Y, the user inputs an operation indicating a restart instruction to the operation unit 163.

In step S09, the image formation process is temporarily stopped, and the process proceeds to step S10. In step S10, it is determined whether or not a restart instruction has been accepted. When the operation unit 163 accepts an operation indicating a restart instruction, it is detected that the restart instruction has been accepted. A standby state is entered until the restart instruction is accepted (NO in step S10), and if the restart instruction has been accepted (YES in step S10), the process proceeds to step S11.

In step S11, the image formation process that was temporarily stopped in step S09 is resumed, and processing returns to step S03.

Figure 11 is a flow chart showing an example of the flow of the drive control process. The drive control process is executed in step S04 of the image formation process, and is executed by CPU 111 of MFP 100 as CPU 111 executes a drive control program stored in CD-ROM 119A. The drive control program is part of the image formation program.

Referring to FIG. 11, the CPU 111 predicts the remaining amount of toner in each of the toner bottles 41Y, 41M, 41C, and 41K (step S21). The remaining amount of toner contained in each of the toner bottles 41Y, 41M, 41C, and 41K is predicted as the remaining amount of toner. Specifically, the remaining amount of toner is predicted based on the number of rotations of each of the toner bottles 41Y, 41M, 41C, and 41K. For example, since the amount of toner discharged from the toner bottle 41Y during one rotation of the toner bottle 41Y is predetermined, the remaining amount of toner in the toner bottle 41Y is calculated based on the number of rotations since the toner bottle 41Y was attached to the MFP 100. The weight of the toner bottle 41Y may also be measured, and the remaining amount may be calculated from the measured weight. The remaining amount of toner in the toner bottle 41Y may also be calculated based on the consumption amount of yellow toner.

In step S22, it is determined whether the minimum remaining toner amount in each of toner bottles 41Y, 41M, 41C, and 41K is greater than the remaining amount threshold. If the minimum remaining toner amount is greater than the remaining amount threshold, the process proceeds to step S23; otherwise, the process proceeds to step S36. In step S36, the first period is determined, and the process proceeds to step S37. In step S37, the first startup method is determined, and the process proceeds to step S32. In step S32, if the process proceeds from step S37, the stepping motor 43a is driven by the first drive method, and the process returns to the image formation process.

In step S23, the second period is determined, and processing proceeds to step S24. In step S24, the second driving method is determined, and processing proceeds to step S25. In step S25, the user is notified that it is the second period, and processing proceeds to step S26. For example, a message or image indicating that toner bottles 41Y, 41M, 41C, and 41K are being rotated using the second driving method during the second period is displayed on the display unit 161.

In step S26, it is determined whether the toner remaining amount in at least one of the toner bottles 41Y, 41M, 41C, and 41K is equal to or greater than the remaining amount threshold. If the toner remaining amount in at least one of the toner bottles 41Y, 41M, 41C, and 41K is equal to or greater than the remaining amount threshold, the process proceeds to step S33; if not, the process proceeds to step S27.

In step S33, the first force-based driving method is selected, and the process proceeds to step S34. In this embodiment, a second driving method is selected to drive the stepping motor 43a using the second excitation method. This is the case when the remaining toner amount in at least one of the toner bottles 41Y, 41M, 41C, and 41K is equal to or greater than the remaining amount threshold, or when the total remaining toner amount in each of the toner bottles 41Y, 41M, 41C, and 41K is equal to or greater than a predetermined value. In this case, the load on the stepping motor 43a increases, so the maximum value of the force that the stepping motor 43a applies to the toner bottles 41Y, 41M, 41C, and 41K is reduced to prevent the bottle rotation mechanism 43 including the stepping motor 43a from being overloaded and from being damaged.

In step S34, it is determined whether or not a user is present within a predetermined range from the MFP 100. If a user is present within the predetermined range from the MFP 100, the process proceeds to step S35; otherwise, step S35 is skipped and the process proceeds to step S32. In step S35, the second sound-based drive method is selected, and the process proceeds to step S32. In this embodiment, the second drive method, which has a greater number of accelerations and decelerations than the first drive method, is selected. This results in a lower volume of sound than the sound generated when the stepping motor 43a is driven by the second drive method, which drives the stepping motor 43a using the second excitation method, and therefore prevents the user from mistaking the sound for an abnormal sound.

In step S32, if the process proceeds from step S34, the stepping motor 43a is driven by the first force-based drive method, which in this embodiment is the second drive method that drives the stepping motor 43a by the second excitation method, and the process returns to the image formation process. In step S32, if the process proceeds from step S35, the stepping motor 43a is driven by the second sound-based drive method, which in this embodiment is the second drive method with two accelerations and decelerations, and the process returns to the image formation process.

In step S27, it is determined whether the toner consumption is equal to or greater than the consumption threshold. Based on the print data for each of cyan, magenta, yellow, and black toners to be used in image formation, the toner consumption for each of cyan, magenta, yellow, and black to be consumed by the image forming unit 140 is predicted, and it is determined whether the toner consumption is equal to or greater than the consumption threshold. If the toner consumption is equal to or greater than the consumption threshold, the process proceeds to step S28, but if not, the process proceeds to step S29. In step S28, the second time-based drive method is determined, and the process proceeds to step S30. In this embodiment, a second drive method that has a larger angular acceleration than the first drive method is determined. In step S29, the first time-based drive method is determined, and the process proceeds to step S30. In this embodiment, a second drive method that drives the stepping motor 43a using the second excitation method is determined.

In step S30, it is determined whether or not a user is present within a predetermined range from the MFP 100. If a user is present within the predetermined range from the MFP 100, the process proceeds to step S31; otherwise, step S31 is skipped and the process proceeds to step S32. In step S31, the second sound-based drive method is selected, and the process proceeds to step S32. In this embodiment, the second drive method, which has a greater number of accelerations and decelerations than the first drive method, is selected. This results in a lower volume of sound than the sound generated when the stepping motor 43a is driven by the second drive method, which increases the angular acceleration more than the first drive method, or the second drive method, which drives the stepping motor 43a with the second excitation method, and therefore prevents the user from mistaking the sound for an abnormal sound.

In step S32, if the process proceeds from step S30, and step S28 is executed, the stepping motor 43a is driven by the second time-based drive method, which in this embodiment is a second drive method that drives the stepping motor 43a with a larger angular acceleration than the first drive method, and the process returns to the image formation process. In step S32, if the process proceeds from step S30, and step S29 is executed, the stepping motor 43a is driven by the first time-based drive method, which in this embodiment is a second drive method that drives the stepping motor 43a with a second excitation method, and the process returns to the image formation process. In step S32, if the process proceeds from step S31, the stepping motor 43a is driven by the second sound-based drive method, which in this embodiment is a second drive method with two accelerations and decelerations, and the process returns to the image formation process.

<Modification>
In the present embodiment, as an example of the second driving method in which the external forces applied to the toner bottles 41Y, 41M, 41C, and 41K while each of the toner bottles 41Y, 41M, 41C, and 41K rotates by a predetermined rotation amount R1, an example in which the angular acceleration, the excitation method, and the number of acceleration and deceleration times are different from each other is shown. The second driving method may be different from the first driving method in at least one of the angular acceleration, the excitation method, and the number of acceleration and deceleration times.

For example, if the angular acceleration in the second driving method is greater than the angular acceleration in the first driving method, the stepping motor 43a is driven by the first driving method in the first period, and the stepping motor 43a is driven by the second driving method in the second period. Also, if the angular velocity V1 is set to a large value, the time T2 for driving the stepping motor 43a becomes shorter.

In addition, when the second driving method is a driving method for driving the stepping motor 43a with a second excitation method different from the first excitation method of the first driving method, the stepping motor 43a is driven with the first excitation method in the first period, and the stepping motor 43a is driven with the second excitation method in the second period.

In addition, when the number of accelerations and decelerations in the second driving method is made greater than the number of accelerations and decelerations in the first driving method, the stepping motor 43a is driven by the first driving method with one acceleration and deceleration in the first period, and the stepping motor 43a is driven by the second driving method with two accelerations and decelerations in the second period. Also, the angular velocity V1 may be set to a large value. In this case, the time T3 for driving the stepping motor 43a may be less than or equal to the time T1 in the first driving method.

The second driving method may be a driving method that drives the stepping motor 43a with an angular acceleration greater than that of the first driving method, and drives the stepping motor 43a with a second excitation method that is smaller than the number of steps per unit rotation angle in the first excitation method in the first driving method. The second driving method may be a driving method that drives the stepping motor 43a with an angular acceleration greater than that of the first driving method, and drives the stepping motor 43a with a greater number of accelerations and decelerations than the number of accelerations and decelerations in the first driving method.

The second driving method may also be a second excitation method with a smaller number of steps per unit rotation angle than the first driving method, and with a greater number of accelerations and decelerations than the first driving method.

In this case, if the sum of the remaining amounts of toner contained in each of the toner bottles 41Y, 41M, 41C, and 41K is equal to or greater than a predetermined value, the angular acceleration is not increased more than in the first driving method. This prevents damage to the bottle rotation mechanism 43.

In addition, when the toner consumption amount of any of toner bottles 41Y, 41M, 41C, and 41K is equal to or greater than the consumption threshold, the time for driving stepping motor 43a is set to be no longer than time T1 in the first driving method. For example, stepping motor 43a is driven by a second driving method that increases the angular acceleration compared to the first driving method. In addition, the maximum value of the angular velocity of stepping motor 43a may be large.

When a user is detected within a predetermined distance from the MFP 100, the stepping motor 43a is driven by a second driving method with a volume equal to or less than the volume of the sound generated when the stepping motor 43a is driven by the first driving method. For example, the second driving method is a driving method that drives the stepping motor 43a with an angular acceleration whose maximum value of angular acceleration of the stepping motor 43a is equal to or less than the angular acceleration in the first driving method. The second driving method is a driving method that drives the stepping motor 43a with a first excitation method whose number of steps per unit rotation of the stepping motor 43a is equal to or less than the number of steps per unit rotation in the first driving method.

As described above, the MFP 100 in this embodiment functions as an image forming device and includes a toner bottle 41Y containing toner, a bottle rotation mechanism 43 that rotates the toner bottle 41Y in a predetermined direction to discharge the toner outside the toner bottle 41Y, and a CPU 111 that controls the bottle rotation mechanism 43. The CPU 111 drives the bottle rotation mechanism 43 by a first driving method during a first period, and drives the bottle rotation mechanism 43 by a second driving method in which the external force applied to the toner bottle 41Y is different from that of the first driving method while the toner bottle 41Y rotates by a predetermined amount during a second period after the first period. Therefore, since the force applied to the toner contained in the toner bottle 41Y is different between the first period and the second period, the toner contained in the toner bottle 41Y can be discharged from the toner bottle 41Y more easily during the second period than during the first period. Therefore, the appropriate amount of toner can be discharged from toner bottle 41Y regardless of the amount of toner contained in toner bottle 41Y.

In addition, the absolute value of the angular acceleration of toner bottle 41Y is greater in the second driving method than in the first driving method. Therefore, the force applied to the toner contained in toner bottle 41Y is greater in the second driving method than in the first driving method, so the degree to which the fluidity of the toner decreases during the second period can be reduced.

In addition, the second driving method has a greater number of acceleration and deceleration operations in which the toner storage container accelerates and decelerates than the first driving method. Since the force applied to the toner stored in the toner bottle 41Y fluctuates more frequently in the second driving method than in the first driving method, the degree to which the fluidity of the toner decreases during the second period can be reduced.

The bottle rotation mechanism 43 also includes a stepping motor 43a as a drive source, and the second drive method has a smaller number of steps per unit rotation angle for driving the stepping motor 43a than the first drive method. Therefore, the amount of fluctuation in the force applied to the toner contained in the toner bottle 41Y is greater in the second drive method than in the first drive method, so that the degree to which the fluidity of the toner decreases during the second period can be reduced.

The CPU 111 also predicts the remaining amount of toner in the toner bottle 41Y and determines whether the first period or the second period is selected based on the predicted remaining amount of toner. The fluidity of the toner affects the amount of toner discharged from the toner bottle 41Y per unit rotation when the amount of toner contained in the toner bottle 41Y is small. Therefore, for example, the second period can be appropriately determined by determining the remaining amount of toner at which the fluidity of the toner affects the amount of toner discharged from the toner bottle 41Y per unit rotation.

The bottle rotation mechanism 43 also drives the multiple toner bottles 41Y, 41M, 41C, and 41K simultaneously, and the CPU 111 determines that the period is the first period when the minimum value of the remaining toner amount predicted for each of the multiple toner bottles 41Y, 41M, 41C, and 41K is greater than the remaining amount threshold, and determines that the period is the second period when the minimum value is equal to or less than the remaining amount threshold. Therefore, even if the amounts of toner contained in the multiple toner bottles 41Y, 41M, 41C, and 41K are different, the second period can be appropriately determined.

The second driving method includes a first force-based driving method in which the maximum value of the force applied by the bottle rotation mechanism 43 to the toner bottles 41Y, 41M, 41C, and 41K is equal to or less than the maximum value of the force applied by the bottle rotation mechanism 43 to the toner bottles 41Y, 41M, 41C, and 41K in the first driving method, and a second force-based driving method in which the maximum value of the force applied by the bottle rotation mechanism 43 to the toner bottles 41Y, 41M, 41C, and 41K is greater than the maximum value of the force applied by the bottle rotation mechanism 43 to the toner bottles 41Y, 41M, 41C, and 41K in the first driving method. When the load on the bottle rotation mechanism 43 is greater than the load threshold, the CPU 111 drives the driving unit by the first force-based driving method during the second period without driving the driving unit by the second force-based driving method. This prevents the bottle rotation mechanism 43 from becoming overloaded.

The second driving method includes a first time-based driving method in which the time required for the bottle rotation mechanism 43 to rotate the toner bottle 41Y a predetermined amount of rotation is equal to or longer than the time required for the first driving method, and a second time-based driving method in which the time required for the bottle rotation mechanism 43 to rotate the toner bottle 41Y a predetermined amount of rotation is equal to or longer than the time required for the first driving method, and the CPU 111 predicts a toner consumption amount indicating the amount of toner consumed by the developing device 24Y that forms an image based on the toner discharged from the toner bottle 41Y, and if the predicted toner consumption amount is equal to or greater than the consumption threshold, drives the driving unit by the first time-based driving method during the second period without driving the driving unit by the second time-based driving method. Therefore, even if the toner consumption amount is large, an appropriate amount of toner can be discharged from the toner storage container.

The second driving method includes a first sound-based driving method in which the volume of the sound generated while the toner bottle 41Y is rotated a predetermined amount by the bottle rotation mechanism 43 is equal to or lower than that of the first driving method, and a second sound-based driving method in which the volume is higher than that of the first driving method. When the CPU 111 detects a user present within a predetermined range from the MFP 100, the CPU 111 drives the driving unit by the first sound-based driving method without driving the driving unit by the second sound-based driving method during the second period. This makes it possible to prevent a user present within a predetermined range from the MFP 100 from hearing a sound with a volume higher than the volume of the sound generated while the toner bottle 41Y is rotated a predetermined amount by the bottle rotation mechanism 43 in the first driving method. Therefore, the bottle rotation mechanism 43 is driven so that the user present within a predetermined range from the MFP 100 does not hear the sound as an abnormal sound.

In addition, the CPU 111 detects the remaining amount of toner contained in the sub-hopper 42Y, and drives the bottle rotation mechanism 43 when the remaining amount of toner contained in the sub-hopper 42Y falls below the lower threshold. This makes it possible to maintain a state in which the sub-hopper 42Y contains toner at or above the lower threshold.

The CPU 111 also notifies the user while the drive unit is being driven using the second drive method. This prevents the user from mistaking the change in sound generated by the bottle rotation mechanism 43 for an error.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

<Additional Notes>
(1) Preferably, the toner storage device further includes a remaining amount predicting unit for predicting a remaining amount of toner in the toner storage container,
The drive control means determines that the load of the drive unit is greater than the load threshold when at least one of the remaining toner amounts in each of the plurality of toner storage containers predicted by the remaining amount prediction means is equal to or greater than a remaining amount threshold.
(2) Preferably, the toner storage container further includes an empty determination means for determining that it is time to replace the toner storage container when the remaining amount of toner stored in the sub hopper is equal to or less than the lower threshold value after the drive control means has driven the drive unit for the predetermined time.
(3) Preferably, in the second driving method, an external force applied to the toner storage container while the toner storage container rotates a predetermined amount in the second period is different from that in the first driving method.

100 MFP, 110 main circuit, 111 CPU, 112 communication I/F section, 113 ROM, 114 RAM, 116 HDD, 117 facsimile section, 118 human sensor, 119 external storage device, 119A CD-ROM, 120 automatic document feeder, 130 document reading section, 140 image forming section, 150 paper feed section, 160 operation panel, 161 display section, 163 operation section, 20Y, 20M, 20C, 20K image forming unit, 21Y, 21M, 21C, 21K exposure head, 22Y, 22M, 22C, 22K electric charger, 23Y, 23M, 23C, 23K photoconductor drum, 24Y, 24M, 24C, 24K Developing unit, 41Y, 41M, 41C, 41K toner bottle, 42Y, 42M, 42C, 42K sub hopper, 43 bottle rotation mechanism, 43a stepping motor, 51 drive control unit, 53 remaining amount prediction unit, 55 consumption amount prediction unit, 57 hopper drive unit, 59 empty determination unit, 61 proximity user determination unit, 63 notification unit, 67 drive amount determination unit, 70 toner consumption amount determination unit, 71 period determination unit, 73 first drive unit, 75 second drive unit, 77 remaining toner amount determination unit, 79 toner consumption amount determination unit.

Claims (17)

a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container;
A drive control means for controlling the drive unit,
the drive control means drives the drive unit by a first drive method during a first period, and drives the drive unit by a second drive method different from the first drive method during a second period after the first period, the second drive method being different from the first drive method in accordance with an external force applied to the toner storage container ;
The image forming apparatus, wherein the second driving method has an absolute value of angular acceleration of the toner storage container that is greater than that of the first driving method . The image forming apparatus according to claim 1, wherein the second driving method is different from the first driving method in the external force applied to the toner container while the toner container rotates a predetermined amount of rotation during the second period. 3. The image forming apparatus according to claim 1 , wherein the second driving method includes a greater number of acceleration and deceleration operations of accelerating and decelerating the toner storage container than the first driving method. a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container;
A drive control means for controlling the drive unit,
the drive control means drives the drive unit by a first drive method during a first period, and drives the drive unit by a second drive method different from the first drive method during a second period after the first period, the second drive method being different from the first drive method in accordance with an external force applied to the toner storage container;
The drive unit includes a stepping motor as a drive source,
The image forming apparatus, wherein the second driving method has a smaller number of steps per unit rotation angle for driving the stepping motor than the first driving method. a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container;
A drive control means for controlling the drive unit;
a remaining amount predicting unit for predicting a remaining amount of toner in the toner storage container,
the toner storage container is a plurality of containers, and the driving unit drives the plurality of containers simultaneously;
the drive control means drives the drive unit by a first drive method during a first period, and drives the drive unit by a second drive method different from the first drive method during a second period after the first period, and determines that the period is the first period when a minimum value of the remaining toner amounts predicted by the remaining amount prediction means for each of the multiple toner storage containers is greater than a remaining amount threshold, and determines that the period is the second period when the minimum value is equal to or less than the remaining amount threshold . a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container;
A drive control means for controlling the drive unit,
the drive control means drives the drive unit by a first drive method during a first period, and drives the drive unit by a second drive method different from the first drive method during a second period after the first period, the second drive method being different from the first drive method in accordance with an external force applied to the toner storage container;
the second driving method includes a first force-based driving method in which a maximum value of the force applied by the driving unit to the toner storage container is equal to or smaller than a maximum value of the force applied by the driving unit to the toner storage container in the first driving method, and a second force-based driving method in which a maximum value of the force applied by the driving unit to the toner storage container is greater than a maximum value of the force applied by the driving unit to the toner storage container in the first driving method,
An image forming apparatus, wherein when the load of the drive unit is greater than a load threshold, the drive control means drives the drive unit by the first force-based drive method during the second period without driving the drive unit by the second force - based drive method. a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container;
A drive control means for controlling the drive unit,
the drive control means drives the drive unit by a first drive method during a first period, and drives the drive unit by a second drive method different from the first drive method during a second period after the first period to control an external force applied to the toner storage container;
the second driving method includes a first time reference driving method in which a time period during which the driving unit rotates the toner storage container by a predetermined rotation amount is equal to or longer than a time period during which the driving unit rotates the toner storage container by a predetermined rotation amount in the first driving method, and a second time reference driving method in which a time period during which the driving unit rotates the toner storage container by a predetermined rotation amount is shorter than a time period during which the driving unit rotates the toner storage container by a predetermined rotation amount in the first driving method,
a developing unit for forming an image based on the toner discharged from the toner storage container;
a toner consumption prediction unit that predicts a toner consumption amount indicating an amount of the toner consumed by the developing unit,
An image forming apparatus, wherein when the toner consumption predicted by the consumption prediction means is equal to or greater than a consumption threshold, the drive control means drives the drive unit using the second time reference drive method without driving the drive unit using the first time reference drive method during the second period. a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container;
A drive control means for controlling the drive unit,
the drive control means drives the drive unit by a first drive method during a first period, and drives the drive unit by a second drive method different from the first drive method during a second period after the first period to control an external force applied to the toner storage container;
the second driving method includes a first sound-based driving method in which the volume of a sound generated while the toner storage container is rotated by the driving unit by a predetermined rotation amount is greater than that of the first driving method, and a second sound-based driving method in which the volume of a sound generated while the toner storage container is rotated by the driving unit by a predetermined rotation amount is less than that of the first driving method,
The device further includes a user detection unit for detecting a user present within a predetermined range from the device itself;
An image forming apparatus, wherein when a user is detected by the user detection means, the drive control means drives the drive unit using the second sound-based drive method without driving the drive unit using the first sound-based drive method during the second period. a sub-hopper for receiving the toner discharged from the toner storage container;
a hopper remaining amount detection unit for detecting a remaining amount of the toner contained in the sub-hopper,
9. The image forming apparatus according to claim 1, wherein the drive control means drives the drive unit in response to a remaining amount of the toner contained in the sub-hopper becoming equal to or less than a lower limit threshold. 10. The image forming apparatus according to claim 1 , further comprising a notification unit that notifies a user while the drive unit is being driven by the second drive method. a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container,
Driving the driving unit by a first driving method in a first period;
and driving the driving unit by a second driving method different from the first driving method, the second driving method being different from the first driving method, so that an external force applied to the toner storage container during a second period that is after the first period is applied to the toner storage container.
The second driving method is a driving control method in which an absolute value of an angular acceleration of the toner storage container is greater than that of the first driving method . a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container,
Driving the driving unit by a first driving method in a first period;
and driving the driving unit by a second driving method different from the first driving method, the second driving method being different from the first driving method, so that an external force applied to the toner storage container during a second period that is after the first period is applied to the toner storage container.
The drive unit includes a stepping motor as a drive source,
The second driving method is a driving control method in which the number of steps per unit rotation angle for driving the stepping motor is smaller than that of the first driving method. a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container,
the toner storage container is a plurality of containers, and the driving unit drives the plurality of containers simultaneously;
a remaining amount prediction step of predicting a remaining amount of toner in the toner storage container;
Driving the driving unit by a first driving method in a first period;
driving the driving unit by a second driving method different from the first driving method in a second period after the first period, the second driving method being different from the first driving method, so that an external force is applied to the toner storage container;
a step of determining that the period is the first period when a minimum value of the remaining toner amount predicted in the remaining amount prediction step for each of the plurality of toner storage containers is greater than a remaining amount threshold, and determining that the period is the second period when the minimum value is equal to or less than the remaining amount threshold. a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container,
Driving the driving unit by a first driving method in a first period;
and driving the driving unit by a second driving method different from the first driving method, the second driving method being different from the first driving method, so that an external force applied to the toner storage container during a second period that is after the first period is applied to the toner storage container.
the second driving method includes a first force-based driving method in which a maximum value of the force applied by the driving unit to the toner storage container is equal to or smaller than a maximum value of the force applied by the driving unit to the toner storage container in the first driving method, and a second force-based driving method in which a maximum value of the force applied by the driving unit to the toner storage container is greater than a maximum value of the force applied by the driving unit to the toner storage container in the first driving method,
A drive control method comprising the step of driving the drive unit by the first force-based driving method without driving the drive unit by the second force-based driving method during the second period when the load of the drive unit is greater than a load threshold. a toner storage container in which toner is stored;
A drive control method executed in an image forming apparatus including a drive unit that rotates a toner storage container in a predetermined direction in order to discharge the toner to the outside of the toner storage container, and a developing unit that forms an image based on the toner discharged from the toner storage container, comprising:
Driving the driving unit by a first driving method in a first period;
and driving the driving unit by a second driving method different from the first driving method, the second driving method being different from the first driving method, so that an external force applied to the toner storage container during a second period that is after the first period is applied to the toner storage container.
the second driving method includes a first time reference driving method in which a time period during which the driving unit rotates the toner storage container by a predetermined rotation amount is equal to or longer than a time period during which the driving unit rotates the toner storage container by a predetermined rotation amount in the first driving method, and a second time reference driving method in which a time period during which the driving unit rotates the toner storage container by a predetermined rotation amount is shorter than a time period during which the driving unit rotates the toner storage container by a predetermined rotation amount in the first driving method,
a consumption amount prediction step of predicting a toner consumption amount indicating an amount of the toner consumed by the developing means;
The drive control method further includes a step of driving the drive unit by the second time reference drive method without driving the drive unit by the first time reference drive method during the second period when the toner consumption predicted in the consumption prediction step is equal to or greater than a consumption threshold value. a toner storage container in which toner is stored;
a drive unit that rotates the toner storage container in a predetermined direction to discharge the toner to the outside of the toner storage container,
Driving the driving unit by a first driving method in a first period;
and driving the driving unit by a second driving method different from the first driving method, the second driving method being different from the first driving method, so that an external force applied to the toner storage container during a second period that is after the first period is applied to the toner storage container.
the second driving method includes a first sound-based driving method in which the volume of a sound generated while the toner storage container is rotated by the driving unit by a predetermined rotation amount is greater than that of the first driving method, and a second sound-based driving method in which the volume of a sound generated while the toner storage container is rotated by the driving unit by a predetermined rotation amount is less than that of the first driving method,
a user detection step of detecting a user present within a predetermined range from the own device;
The drive control method further includes a step of driving the drive unit with the second sound-based drive method without driving the drive unit with the first sound-based drive method during the second period when a user is detected in the user detection step. A drive control program that causes a computer to execute the drive control method according to any one of claims 11 to 16.

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