JP2017215523A - Image forming apparatus and method for controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for starting excitation at an appropriate timing in starting up a stepping motor used in a toner supply mechanism in an image forming apparatus.SOLUTION: A CPU 400 of an image forming apparatus (MFP) determines the amount of toner remaining in a developing unit 140 (the number of times N an ON signal is output from a toner sensor). When the CPU 400 stops a conveyance path motor 211 (S105), then turns off the excitation of the conveyance path motor 211 (S108). The CPU 400 subsequently starts the excitation of the conveyance path motor 211 before starting up the conveyance path motor 211 at a timing at which the amount of toner in the developing unit 140 falls below a predetermined threshold N(S110).SELECTED DRAWING: Figure 4

Description

  The present invention relates to an electrophotographic image forming apparatus and a control method thereof.

  In image forming apparatuses such as printers and copiers, stepping motors are widely used as drive sources for sheet conveying mechanisms and toner supply mechanisms. The stepping motor is driven to rotate when the windings of the respective phases are excited in a predetermined order (current is supplied). A stepping motor that is stopped in a non-excited state where no current is supplied takes a certain time to start (start) when the supply of current is resumed. For this reason, in order to improve the responsiveness of a stepping motor, the excitation state of a stepping motor may be maintained even during a stop period. In this case, it is possible to reduce the power consumption during the stop period by not starting the excitation state throughout the stop period but starting the excitation of the stepping motor a predetermined time before the start timing.

JP 2008-253139 A

  In the above-described technique, excitation of the stepping motor is started a predetermined time before the start timing with reference to a predetermined start timing of the stepping motor. However, the stepping motor used in the toner replenishing mechanism is intermittently started and stopped in accordance with the toner replenishment interval from the toner storage container (toner bottle) to the developing device. In this case, since the start timing of the stepping motor changes depending on the toner supply interval, the start timing cannot be specified in advance. Therefore, in order to apply the above-described technique to the stepping motor used for the toner replenishing mechanism, a mechanism for controlling the timing of starting excitation before starting the stepping motor is required.

  The present invention has been made in view of the above-described problems, and provides a technique for starting excitation at an appropriate timing when starting a stepping motor used in a toner supply mechanism in an image forming apparatus. With the goal.

  The present invention can be realized as an image forming apparatus, for example. An image forming apparatus according to an aspect of the present invention includes a replenishing unit that replenishes image forming toner to a developing device, a stepping motor that drives the replenishing unit, and a detection that detects a remaining amount of toner in the developing device. And a timing at which excitation of the stepping motor is started before the stepping motor is started for supplying toner to the developing device based on the remaining amount of toner detected by the detecting unit. And a control means.

  According to another aspect of the present invention, an image forming apparatus includes a replenishing unit that replenishes image forming toner to a developing device, a stepping motor that drives the replenishing unit, and a determination that determines a toner consumption amount in image formation. And control means for controlling the timing for starting excitation of the stepping motor before the stepping motor is started for replenishing toner to the developing device based on the determined toner consumption amount; It is characterized by providing.

  According to the present invention, in the image forming apparatus, it is possible to start excitation at an appropriate timing when starting the stepping motor used in the toner supply mechanism.

FIG. 3 is a cross-sectional view illustrating a configuration of an MFP. FIG. 3 is a schematic diagram illustrating a configuration of a toner supply unit. FIG. 2 is a block diagram showing a configuration of a control system of the MFP. The flowchart which shows the procedure of motor drive control. FIG. 6 is a diagram illustrating an example of a relationship among a printing rate, an image forming speed, and a toner consumption amount. FIG. 6 is a diagram illustrating an example of a correspondence relationship between toner consumption and excitation OFF period.

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

  The image forming apparatus according to the present embodiment is an apparatus that forms an image on a sheet by an electrophotographic method, such as a printing apparatus (printer), a copier, a multifunction peripheral (MFP), and a facsimile machine. Note that a multifunction peripheral is an apparatus having at least two or more functions among a plurality of types of functions including, for example, a print function, a scan function, a copy function, and a facsimile function. Here, a case where the image forming apparatus is an MFP having a printing function, a scanning function, and a copying function will be described.

<Image forming apparatus (MFP)>
FIG. 1 is a cross-sectional view illustrating a configuration of the MFP 100 according to the present embodiment. The MFP 100 may be an image forming apparatus that forms a multicolor image using a plurality of colors of toner (developer), but an image forming apparatus that forms a single color image using a single color toner will be described. The MFP 100 includes a printer unit 101 that forms an image on a sheet, a reader unit 102 that reads an image of a document, and an ADF unit 103 that transports a document to be read. The sheet may be referred to as recording paper, recording material, recording medium, paper, transfer material, transfer paper, or the like.

  In the printer unit 101, the recording paper P stored in the paper feed cassette 110 is fed to the transport path one by one by the pickup roller 111, the paper feed roller 112 and the retard roller 113. The recording paper P fed from the paper feed cassette 110 is transported along the transport path by the transport roller 114. When the recording paper P reaches the position of the registration roller pair 115, skew correction is performed by the stopped registration roller pair 115. Thereafter, when the registration roller pair 115 starts to rotate, the recording paper P is conveyed to the transfer nip portion between the photosensitive drum 131 and the transfer roller 133.

  In the printer unit 101, the laser scanner unit 120, the photosensitive drum (photosensitive member) 131, the charging roller 132, the transfer roller 133, and the developing device 140 constitute an image forming unit that forms an image on the recording paper P. In the image forming portion, the outer peripheral surface of the rotationally driven photosensitive drum 131 is uniformly charged to a predetermined polarity potential by the action of the charging roller 132. The laser scanner unit 120 exposes the charged photosensitive drum 131 with a light beam (laser light). Specifically, the laser scanner unit 120 outputs laser light L that is modulated according to image information (time-series digital pixel signals), and scans the charged photosensitive drum 131 with the laser light L, thereby performing photosensitivity. An electrostatic latent image is formed on the drum 131. The laser scanner unit 120 uses the laser beam L based on image data (image information) obtained by reading an image of a document by the reader unit 102 or image data received from an external device such as a PC via a network. Is output.

  The developing device 140 includes a developing roller 141 and develops the electrostatic latent image on the photosensitive drum 131 using toner supplied (supplied) from the toner replenishing unit 150 to form a toner image. The toner image formed on the photosensitive drum 131 moves to the transfer nip portion as the photosensitive drum 131 rotates. By applying a transfer bias having a polarity opposite to that of the photosensitive drum 131 to the transfer roller 133, the toner image on the photosensitive drum 131 is transferred to the surface of the recording paper P at the transfer nip portion.

  The recording paper P on which the toner image is transferred in the image forming unit is conveyed into the fixing device 160. The fixing device 160 fixes the toner image on the recording paper P to the recording paper P by applying heat and pressure to the recording paper P by a fixing heater and a pressure roller. The recording paper P on which an image has been formed in this manner is discharged (discharged) to the discharge tray 171 outside the apparatus by the discharge roller 170 after passing through the fixing device 160.

  When double-sided printing is performed on the recording paper P, the recording paper P on which image formation on the first surface has been completed is transported in the reverse direction by the paper discharge roller 170 after passing through the position of the reverse flapper 181 and reversed. It is guided to the reverse conveyance path 180 by the flapper 181. The recording paper P guided to the reverse conveyance path 180 is conveyed again to the position of the registration roller pair 115 by the conveyance rollers 182 and 183. At that time, the recording paper P is in a state in which the first surface and the second surface are reversed as compared with the image formation on the first surface. Thereafter, the recording paper P is discharged to the paper discharge tray 171 after the image formation on the second surface is performed in the same manner as the image formation on the first surface.

  As described above, in the image forming apparatus of the present embodiment, the image forming unit is an example of an image forming unit that includes the developing device 140 and forms an image using the toner supplied by the toner replenishing unit 150. The toner replenishing unit 150 is an example of a replenishing unit that replenishes the developing device 140 with toner for image formation. In this embodiment, an agitation member (not shown) provided inside the developing device 140 for conveying the toner in the developing device 140 while stirring also functions as an example of a replenishing unit.

<Toner supply part>
FIG. 2 is a schematic diagram illustrating the configuration of the toner replenishing unit 150 in the MFP 100. A toner bottle (toner storage container) 200 pre-filled with toner is installed in the toner supply unit 150 by the user. The toner supply unit 150 includes a toner bottle 200, a bottle motor 201, a toner transport path 210, a screw 212 provided in the toner transport path 210, and a transport path motor 211. The toner conveyance path 210 is provided between the toner bottle 200 and the developing device 140 and corresponds to a toner hopper (storage unit) that stores toner discharged (supplied) from the toner bottle 200. The toner conveyance path 210 is used for conveying the toner discharged from the toner bottle 200 to the developing device 140.

  The rotation axis of the toner bottle 200 is connected to the bottle motor 201 via a drive gear train (not shown), and a rotational driving force can be applied from the bottle motor 201 via the drive gear train. When the bottle motor 201 is driven to rotate, the toner bottle 200 rotates in the direction indicated by the arrow A. As the toner bottle 200 is driven and rotated by the bottle motor 201, the toner is discharged from the inside of the toner bottle 200 and flows into the toner conveyance path 210.

  A screw 212 is provided in the toner conveyance path 210. The rotation shaft of the screw 212 is connected to the conveyance path motor 211 via a drive gear train (not shown), and a rotational driving force is applied from the conveyance path motor 211 via the drive gear train. As described above, a power transmission mechanism that transmits a driving force from the conveyance path motor 211 to the screw 212 is provided between the conveyance path motor 211 and the screw 212. The screw 212 is driven and rotated by the conveyance path motor 211 to convey the toner flowing from the toner bottle 200 into the toner conveyance path 210 in one direction (from left to right in FIG. 2). The toner conveyed through the toner conveyance path 210 is discharged to the developing device 140 at the end of the toner conveyance path 210.

  Inside the developing device 140, a toner sensor 221 for detecting the presence or absence of toner in the developing device 140 is provided. The developing unit 140 includes a stirring member (not shown) that transports the toner in the developing unit 140 while stirring the toner in the developing unit 140. As will be described later, the stirring member is rotationally driven by a stirring motor 421 (FIG. 3). In the present embodiment, the bottle motor 201, the conveyance path motor 211, and the agitation motor 421 are each composed of a stepping motor and function as an example of a stepping motor that drives the replenishing means.

<MFP control system>
FIG. 3 is a block diagram showing the configuration of the control system of MFP 100 according to the present embodiment. FIG. 3 shows a configuration particularly related to the present embodiment, such as motor drive control described later. The MFP 100 includes a CPU 400, a ROM 401, a RAM 402, and an EEPROM 403 as a control system.

  The ROM 401 stores a control program for controlling the entire MFP 100. The RAM 402 is a volatile storage device (memory) that is used as a work area of the CPU 400 and is used for temporarily storing various data such as image data. CPU 400 controls MFP 100 as a whole by reading a control program stored in ROM 401 into RAM 402 and executing it. The EEPROM 403 is a non-volatile storage device (memory) and is used to hold various data such as the remaining amount of toner in the toner bottle 200. The operation unit 410 includes a display unit (liquid crystal display or the like), receives a user operation, transmits operation information indicating the content of the user operation to the CPU 400, and operates an operation screen based on the screen information transmitted from the CPU 400. Is displayed on the display.

  The MFP 100 includes a motor drive circuit 411 that drives the bottle motor 201 by supplying a drive current to the bottle motor 201, and a motor drive circuit 412 that drives the transport path motor 211 by supplying a drive current to the transport path motor 211. Yes. The CPU 400 controls the operation of the toner replenishing unit 150 by performing drive control of the bottle motor 201 and the conveyance path motor 211 via the motor drive circuits 411 and 412, respectively. The MFP 100 further includes a motor drive circuit 413 that supplies a drive current to the stirring motor 421 to drive the stirring motor 421. The CPU 400 controls the stirring and transporting operation of the toner by the stirring member in the developing device 140 by controlling the driving of the stirring motor 421 via the motor driving circuit 413.

  A signal output from the toner sensor 221 of the developing device 140 is input to the CPU 400. The CPU 400 controls the supply (replenishment) of toner from the toner replenishing unit 150 to the developing device 140 based on the signal output from the toner sensor 221. The toner sensor 221 is, for example, a magnetic permeability sensor. When toner containing magnetic material is detected, the toner sensor 221 outputs an ON state signal (ON signal), and when no toner is detected, an OFF state signal (OFF signal). Output. As described above, when the toner sensor 221 detects toner, the toner sensor 221 outputs an ON signal as a detection signal indicating that the toner has been detected.

  The CPU 400 determines (detects) the presence or absence of toner in the developing device 140 based on the output signal from the toner sensor 221. For example, the CPU 400 determines the presence or absence of toner in the developing device 140 based on the number N of ON signal outputs per predetermined unit time from the toner sensor 221. Further, the CPU 400 may determine (detect) the remaining amount of toner in the developing device 140 based on the number N of outputs of the ON signal per predetermined unit time from the toner sensor 221. For example, data indicating the correspondence relationship between the output count N and the remaining amount of toner may be stored in the EEPROM 403 in advance, and the remaining amount of toner may be determined based on such data.

  The CPU 400 performs motor control for controlling the start and stop of the bottle motor 201, the conveyance path motor 211, and the stirring motor 421 according to the remaining amount of toner in the developing device 140 detected using the toner sensor 221. Specifically, the CPU 400 performs a toner supply operation (supply operation) for supplying (supplying) toner from the toner bottle 200 to the developer 140 when the remaining amount of toner in the developer 140 falls below a predetermined threshold. Run. In the toner replenishing operation, the CPU 400 replenishes toner from the toner bottle 200 to the toner transport path 210 by driving the bottle motor 201 to rotate the toner bottle 200. Further, the CPU 400 drives the conveyance path motor 211 to rotate the screw 212 to convey the toner in the toner conveyance path 210 and replenish the toner from the toner conveyance path 210 to the developing device 140. Further, the CPU 400 drives the stirring motor 421 to rotate the stirring member in the developing device 140, thereby conveying the toner to the developing roller 141 while stirring the toner replenished in the developing device 140.

<Outline of motor drive control>
Next, drive control of the stepping motors (bottle motor 201, transport path motor 211, and agitation motor 421) used in the toner supply mechanism according to the present embodiment will be described with reference to FIGS. In the following description, control of timing for starting excitation of the conveyance path motor 211 is mainly described. However, the same control as the conveyance path motor 211 can be applied to the bottle motor 201 and the agitation motor 421.

  As described above, the stepping motor used for the toner replenishment function is driven and controlled to be intermittently started and stopped according to the toner replenishment interval from the toner bottle 200 to the developing device 140. In this case, since the start timing of the stepping motor changes depending on the toner replenishment interval, the start timing of the stepping motor cannot be predetermined. Therefore, in order to start excitation at an appropriate timing when starting the stepping motor, it is necessary to predict the start timing of the motor. Furthermore, it is necessary to control the timing for starting excitation of the stepping motor based on the predicted timing.

  Therefore, the MFP 100 according to the present embodiment determines the toner consumption amount in the image formation executed by the image forming unit. Further, based on the determined toner consumption, the MFP 100 controls the timing at which excitation of the conveyance path motor 211 is started before the conveyance path motor 211 is activated to supply toner to the developing device 140. Specifically, CPU 400 determines a toner consumption amount in image formation by the image forming unit based on an output signal of toner sensor 221. The toner consumption amount corresponds to, for example, toner consumption amount per unit time in image formation, and can be determined based on a change in the remaining amount of toner in the developing device 140 detected from the output signal of the toner sensor 221. is there. Further, when the conveyance path motor 211 is stopped, the CPU 400 predicts the next timing at which the conveyance path motor 211 should be started based on the determined toner consumption. Further, the CPU 400 determines a timing a predetermined time before the predicted timing as a timing at which excitation of the conveyance path motor 211 is started.

  By controlling the timing for starting the excitation of the transport path motor 211 in this way, when starting the transport path motor 211, the excitation is started at an appropriate timing determined according to the start timing of the transport path motor 211. be able to. Therefore, the period during which the conveyance path motor 211 is excited while the conveyance path motor 211 is stopped can be shortened as much as possible, and power consumption while the conveyance path motor 211 is stopped can be suppressed.

<Motor drive control procedure>
FIG. 4 is a flowchart showing a procedure of motor drive control executed in MFP 100 according to the present embodiment. The processing in each step shown in FIG. 4 is realized in MFP 100 under the control of CPU 400 by CPU 400 reading and executing a control program from ROM 401. FIG. 4 shows an example in which the CPU 400 detects the remaining amount of toner in the developing device 140 and controls the timing for starting excitation of the stopped conveyance path motor 211 based on the detected remaining amount of toner. ing.

In S101, the CPU 400 determines whether or not the execution of the print job has started, and if it is determined that the execution of the print job has started (“YES” in S101), the process proceeds to S102. In S102, the CPU 400 determines whether or not the number N of ON signal outputs from the toner sensor 221 per predetermined unit time is less than a predetermined threshold N _th1 (N <N _th1 ). Here, the number N of ON signal outputs corresponds to the remaining amount of toner in the developing device 140. When the toner remaining amount (output count N) in the developing device 140 is below the threshold value N _th1 , the CPU 400 advances the process to S103.

In step S103, the CPU 400 activates the bottle motor 201, the conveyance path motor 211, and the stirring motor 421 that are used in the toner supply mechanism. As a result, execution of a toner supply operation for supplying (supplying) toner from the toner bottle 200 to the developing device 140 is started. In this way, the CPU 400 activates the conveyance path motor 211 when the remaining amount of toner (number of times of output N) in the developing device 140 falls below the threshold value N _th1 while the conveyance path motor 211 is stopped.

Thereafter, in S104, the CPU 400 determines whether or not the remaining amount of toner (number of times of output N) in the developing device 140 is _{equal to} or greater than a predetermined threshold N _th3 . Here, N _th3 is predetermined as a value higher than N _th1 (N _th1 <N _th3 ), and is a threshold value for determining that sufficient toner for image formation exists in the developing device 140. It corresponds to. When the toner remaining amount (output count N) in the developing device 140 changes to a predetermined threshold value N _th3 or more, the CPU 400 advances the process to S105 and stops the bottle motor 201, the conveyance path motor 211, and the stirring motor 421.

Next, in step S106, the CPU 400 determines whether or not the execution of the print job has ended. If the execution of the print job has ended, the process returns to step S101, and if the execution of the print job has not ended. The process proceeds to S107. In step S107, the CPU 400 determines again whether or not the remaining amount of toner (number of times of output N) in the developing device 140 is _{equal to} or greater than the threshold value N _th3 .

If the toner remaining amount (output count N) has already fallen below the threshold value N _th3 in S107, the CPU 400 advances the process to S110 and maintains the excitation state of the transport path motor 211. As a result, when the toner consumption in the image forming unit is large and the toner replenishment interval is short (that is, the time interval at which the conveyance path motor 211 is activated is short), the excitation state of the conveyance path motor 211 is maintained and the conveyance path is maintained. It is possible to prepare for the next activation of the motor 211.

On the other hand, if the toner remaining amount (output count N) is equal to or greater than the threshold value N _th3 in S107, the CPU 400 advances the process to S108 and turns off the excitation of the conveyance path motor 211. Specifically, the CPU 400 stops the supply of drive current from the motor drive circuit 412 to the transport path motor 211, thereby bringing the transport path motor 211 into a non-excited state.

Thereafter, in S109, the CPU 400 determines whether or not the remaining amount of toner (number of times of output N) in the developing device 140 is below the threshold value _Nth2 . Here, N _th2 is determined in advance as a value higher than N _{th1 and} lower than N _th3 (N _th1 <N _th2 <N _th3 ), in order to determine the timing for starting excitation before the transport path motor 211 is started. It corresponds to the threshold value.

When the toner remaining amount (output count N) falls below the threshold value N _th2 in S109, the CPU 400 advances the process to S110 and turns on the excitation of the conveyance path motor 211. Specifically, the CPU 400 resumes the supply of drive current from the motor drive circuit 412 to the transport path motor 211, thereby bringing the transport path motor 211 into an excited state. That is, when reaching the timing for starting excitation while the transport path motor 211 is stopped, the CPU 400 causes the transport path motor 211 to be in an excited state by supplying a drive current from the motor drive circuit 412 to the transport path motor 211. As described above, the CPU 400 determines the timing at which the remaining amount of toner falls below the threshold value N _th2 as the timing at which excitation of the conveyance path motor 211 is started based on the change in the remaining amount of toner in the developing device 140.

After starting the excitation of the conveyance path motor 211, the CPU 400 returns the process to S102. Thereafter, when the remaining amount of toner (output count N) in the developing device 140 falls below the threshold value N _th1 (“YES” in S102), the CPU 400 activates the bottle motor 201, the conveyance path motor 211, and the agitation motor 421 (S103). ). In this way, the CPU 400 repeatedly executes the processes of S102 to S110 while the execution of the print job continues.

As described above, in the present embodiment, the CPU 400 detects the remaining amount of toner (number of outputs N) in the developing device. When the CPU 400 stops the conveyance path motor 211 (S105), the CPU 400 turns off the excitation of the conveyance path motor 211 (S108). Thereafter, the CPU 400 starts excitation of the conveyance path motor 211 at a timing when the remaining amount of toner in the developing device falls below a predetermined threshold N _th2 before the conveyance path motor 211 is activated (S110). Thus, when the conveyance path motor 211 is activated, the excitation of the conveyance path motor 211 can be started at an appropriate timing determined according to the activation timing of the conveyance path motor 211. Therefore, the period during which the conveyance path motor 211 is excited while the conveyance path motor 211 is stopped can be shortened as much as possible, and power consumption while the conveyance path motor 211 is stopped can be suppressed.

<Modification>
In the above-described example, it is assumed that the time for changing the remaining amount of toner in the developing device 140 is constant. However, the amount of toner change per unit time (toner consumption) can also be determined based on the printing rate (necessary for print jobs) and image forming speed (productivity) in image formation by the image forming unit. It is. FIG. 5 is a diagram illustrating an example of the relationship between the printing rate and image forming speed and the toner consumption (X _{1 to} X ₅ ) in the MFP 100. As shown in FIG. 5, the lower the printing rate, the smaller the toner consumption, and the lower the image formation speed, the smaller the toner consumption. Therefore, the CPU 400 may determine that the toner consumption is smaller as the printing rate is lower. Further, the CPU 400 may determine that the toner consumption is smaller as the image forming speed is lower.

When the present modification is applied to the procedure illustrated in FIG. 4, the CPU 400 may determine the timing for turning on the excitation of the conveyance path motor 211 in S <b> 110 based on the toner consumption determined in this way. . For example, the CPU 400 sets the excitation off period T _off from when the excitation of the conveyance path motor 211 is turned off at S108 to when the excitation of the conveyance path motor 211 is turned on at S110 based on the determined toner consumption. May be. As shown in FIG. 6, the excitation off period T _off can be set in advance as a period corresponding to the toner consumption (X _{1 to} X ₅ ) obtained from the relationship shown in FIG.

  Even in such a modification, as in the above-described embodiment, the period during which the conveyance path motor 211 is excited while the conveyance path motor 211 is stopped can be shortened as much as possible, and consumption while the conveyance path motor 211 is stopped. It becomes possible to suppress electric power.

100: MFP (image forming apparatus), 131: photosensitive drum, 140: developing device, 150: toner replenishing unit, 200: toner bottle, 201: bottle motor, 210: toner transport path, 211: transport path motor, 212: screw 221: toner sensor, 400: CPU, 403: EEPROM, 411-413: motor drive circuit, 421: stirring motor

Claims (14)

Replenishment means for replenishing toner for image formation to the developing device;
A stepping motor for driving the replenishing means;
Detecting means for detecting the remaining amount of toner in the developing unit;
Control means for controlling the timing of starting excitation of the stepping motor before starting the stepping motor for replenishing toner to the developing device based on the remaining amount of toner detected by the detecting means; ,
An image forming apparatus comprising: The control means includes
The excitation is started at a timing when the remaining amount detected by the detection unit falls below a second threshold value that is higher than a first threshold value that is a timing at which the stepping motor is activated. Image forming apparatus. Replenishment means for replenishing toner for image formation to the developing device;
A stepping motor for driving the replenishing means;
Determination means for determining toner consumption in image formation;
Control means for controlling the timing of starting excitation of the stepping motor before the stepping motor is started for replenishing toner to the developing device based on the determined toner consumption amount;
An image forming apparatus comprising: When the stepping motor is stopped, the control means predicts the next timing when the stepping motor is started based on the toner consumption determined by the determination means, and is a predetermined time before the predicted timing. The image forming apparatus according to claim 3, wherein a timing is set to a timing at which the excitation is started. The image forming apparatus according to claim 3, wherein the determination unit determines the toner consumption based on a printing rate and an image formation speed in the image formation. The image forming apparatus according to claim 5, wherein the determination unit determines that the toner consumption is smaller as the printing rate is lower. The image forming apparatus according to claim 5, wherein the determination unit determines that the toner consumption is smaller as the image forming speed is lower. The control means increases the length of a period during which the stepping motor is in a non-excited state before the stepping motor is stopped and started as the determined toner consumption amount is smaller. The image forming apparatus according to any one of claims 3 to 7. The image forming apparatus according to claim 3, wherein the toner consumption amount is a toner change amount per unit time in the image formation. The said replenishing means contains the screw which conveys the toner discharged | emitted from the toner storage container by being driven by the said stepping motor to the said developing device. The one of Claim 1 to 9 characterized by the above-mentioned. Image forming apparatus. The replenishing means includes a toner storage container that discharges toner by being driven by the stepping motor, and a toner transport path for transporting the toner discharged from the toner storage container to the developer. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. Motor driving means for supplying a driving current to the stepping motor to drive the stepping motor;
When the timing for starting the excitation is reached while the stepping motor is stopped, the control unit causes the stepping motor to be in an excited state by supplying a driving current from the motor driving unit to the stepping motor. The image forming apparatus according to any one of claims 1 to 11. A control method for an image forming apparatus, comprising: a replenishing unit that replenishes toner for image formation to a developing device; and a stepping motor that drives the replenishing unit,
A detection step of detecting a remaining amount of toner in the developing unit;
A control step of controlling the timing of starting excitation of the stepping motor before the stepping motor is started for replenishing toner to the developing device based on the remaining amount of toner detected in the detection step; ,
A control method for an image forming apparatus. A control method for an image forming apparatus, comprising: a replenishing unit that replenishes toner for image formation to a developing device; and a stepping motor that drives the replenishing unit,
A determination step of determining toner consumption in image formation;
A control step of controlling the timing of starting excitation of the stepping motor before the stepping motor is started for replenishing toner to the developing device based on the determined toner consumption amount;
A control method for an image forming apparatus.

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