JP2009092827A - Image forming device, and method of controlling image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing a driving torque of an agitating member at the start of the image forming device. <P>SOLUTION: The image forming device includes an agitating blade 207 for a toner 208 that is rotated by a motor, and a stepping motor for driving the agitating blade 207. While the stepping motor is rotating, the change in the load torque is monitored. The stop position of the agitating blade is adjusted so that the agitating blade 207 stops at a position where the starting torque becomes small (Fig. (1)). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a method for controlling the image forming apparatus, and more particularly to an image forming apparatus having a developer stirring member such as toner and a method for controlling the image forming apparatus.

  In an image forming apparatus (MFP (Multi Function Peripheral), facsimile apparatus, copying machine, printer, etc.), a developing device that performs development using toner is used. A stirring blade for supplying toner is used in the developing device.

  Patent Document 1 below discloses a developing tank stirring device that prevents an excessive load torque from being applied to a stirring roller when a new toner cartridge is set. A manual drive system gear is provided on the rotating shaft of the agitation roller, and the developer is agitated manually before the developing cartridge is attached to the image forming apparatus.

Patent Document 2 below discloses an image forming apparatus that performs toner replenishment control with an inexpensive configuration using a simple electric circuit without using a large number of toner sensors. The toner replenishing operation and the developing operation are controlled based on the value of the current flowing through the motor that drives the stirring unit. When an overload is detected, control for stopping the drive member is performed.
Japanese Patent Laid-Open No. 5-142939 JP 2000-122394 A

  The first object of the present invention is to provide an image forming apparatus capable of suppressing the drive torque of the stirring member at the start of driving of the image forming apparatus, and a control method for the image forming apparatus.

  Furthermore, a second object of the present invention is to provide an image forming apparatus capable of preventing the stirring member of the image forming apparatus from being bent and a method for controlling the image forming apparatus.

  In order to achieve the above object, according to one aspect of the present invention, an image forming apparatus includes a stirring member, a motor for driving the stirring member, and the stirring member so that the stirring member stops at a position where the starting torque is reduced. Adjusting means for adjusting the position of the.

  According to another aspect of the present invention, an image forming apparatus includes a stirring member, a motor that drives the stirring member, and an adjusting unit that adjusts the position of the stirring member so that the stirring member stops at a position where the stirring member does not bend. .

  Preferably the motor is a stepping motor.

  Preferably, the adjusting means monitors the torque at the time of rotation of the stirring member to grasp the position of the stirring member at the end of printing, and adjusts the position of the stirring member by controlling the step of the stepping motor. However, the position of the stirring member is adjusted so as to stop at the position where the starting torque is lightest.

  Preferably, the adjusting means recognizes the inflection point from the rising state of the current flowing through the motor when grasping the torque during rotation of the stirring member, and the inflection point recognized by the inflection point recognition means. The detection means for detecting the load fluctuation amount based on the point and the setting means for automatically setting the motor current based on the load fluctuation amount detected by the detection means.

  Preferably, the setting means performs current setting based on the result recognized by the inflection point recognition means and the current current setting value.

  Preferably, the image forming apparatus samples the result recognized by the inflection point recognizing unit for a predetermined time, and sets the current based on the maximum and minimum shake widths.

  Preferably, the stirring member is a stirring blade for supplying toner.

  According to still another aspect of the present invention, a control method for an image forming apparatus is a control method for an image forming apparatus including a stirring member and a motor for driving the stirring member, and the stirring member has a starting torque. An adjustment step is provided for adjusting the position of the stirring member so as to stop at a lighter position.

  According to still another aspect of the present invention, a control method for an image forming apparatus includes a stirring member, a motor for driving the stirring member, and a control method for the image forming apparatus, wherein the stirring member stops at a position where the stirring member does not bend. And an adjusting step for adjusting the position of the stirring member.

  According to these inventions, it is possible to provide an image forming apparatus capable of suppressing the drive torque of the stirring member at the start of driving of the image forming apparatus, and a control method for the image forming apparatus.

  In addition, it is possible to provide an image forming apparatus capable of preventing the stirring member of the image forming apparatus from being bent, and a method for controlling the image forming apparatus.

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

  The image forming apparatus includes a developing device, and automatically adjusts the position of the stirring blade so that the starting torque of the stirring blade, which is an example of the stirring member, becomes lightest. Specifically, the image forming apparatus extracts the load fluctuation of the stepping motor from the torque of the stepping motor that drives the stirring blade in the image forming apparatus, and stops the stirring blade at a position where the load torque is lightest.

  The stirrer blade is stopped at a lightly loaded position and the set torque at the start of the stirrer blade drive (when the developer drive is started) is reduced to reduce surplus power and to save energy and reduce noise in the image forming apparatus. .

  In addition, the position of the stirring blade is automatically adjusted so that the stirring blade does not bend. This prevents bending of the stirring blade (creep phenomenon).

  FIG. 1 is a diagram showing a basic configuration of an image forming apparatus according to one embodiment of the present invention.

  Referring to the figure, the image forming apparatus 1 includes a scanner unit 10, a transfer unit 20, a developing unit 30, and a paper feeding unit 40.

  The scanner unit 10 includes a document glass 11 for reading an image from a document placed thereon, an automatic document feeder (ADF) 2 that transports paper onto the document glass, and a document to be read using the ADF. A document placing table 3 for placing the document and a document discharge tray 4 on which the documents read using the ADF are stacked are provided.

  The transfer unit 20 includes a secondary transfer roller 35 for transferring the toner image on the intermediate transfer belt 31 to a sheet at the nip T, a fixing device 36, a paper discharge roller 37, and a paper discharge unit 38. .

  The developing unit 30 includes developing units 20Y, 20M, 20C, and 20K corresponding to yellow (Y), magenta (M), cyan (C), and black (K), an intermediate transfer belt 31, and an intermediate transfer belt. , And transfer rollers 25Y, 25M, and 25C for transferring the toner image formed on the photosensitive member by the developing unit to the intermediate transfer belt 31. , 25K.

  The paper feed unit 40 includes a paper tray 41 that stores a plurality of sheets S for forming an image, a paper feed roller 42, and a paper transport roller 43.

  The image forming apparatus includes an information processing unit 100 including a CPU, a RAM, a ROM, and the like.

  FIG. 2 is a diagram illustrating one configuration of the developing devices 20Y, 20M, 20C, and 20K in the image forming apparatus.

  Referring to the drawing, the developing device has a hopper (toner storage) unit 201 and a buffer (toner supply) unit 202. In this figure, the charging device and the laser light source are omitted.

  This developing device uses a one-component toner and does not have a toner concentration detection sensor. Further, from the viewpoint of cost reduction, there is no toner amount detection sensor.

  According to the number of printed sheets, the stirring blade 207 in the hopper unit 201 rotates to supply the toner 208 from the hopper unit 201 to the buffer unit 202. If the toner in the buffer unit 202 is sufficiently supplied, the pressure in the valve 206 is applied by the toner in the buffer unit 202, and the toner supply from the hopper unit 201 to the buffer unit 202 is stopped. ing. Thereby, toner supply at a constant pressure is performed.

  The toner supplied from the hopper unit 201 to the buffer unit 202 is supplied to the developing roller 204 by the supply roller 203 and is supplied from the developing roller 204 to the photoconductor 205.

  The stirring blade 207 is driven by a motor (stepping motor: stirring blade drive motor) not shown. The torque output by the motor is referred to as “stirring blade torque: t”.

  The motor varies the output torque according to the size of the load by the CPU mounted on the information processing unit 100. The motor is controlled to output a torque with a certain margin in the load torque.

  FIG. 3 is a block diagram illustrating a configuration of the information processing unit 100 of the image forming apparatus.

  An information processing unit (control unit) 100 controls the image forming unit 102.

  The information processing unit 100 includes a data input / output unit 103, a data communication control unit 104, a control device 105, a volatile memory 106, and a stirring blade torque memory 107.

  The control device 105 includes a data writing unit 105a, a CPU 105b, and a RAM 105c.

  The image forming unit 102 includes a developing device driving motor 211 that drives the supply roller 203, the developing roller 204, and the stirring blade 207, and a photoconductor driving motor 213 that drives the photoconductor 205.

  The information processing unit 100 constantly monitors the torque of the stirring blade 207 by the data input / output unit 103, the data communication control unit 104, the control device 105, the volatile memory 106, and the stirring blade torque memory 107, and Controls storage and output. The information processing unit 100 has a function of grasping fluctuations in the torque of the stirring blade 207.

  FIG. 4 is a diagram illustrating a stepping motor drive circuit included in the control device 105.

  Here, it is assumed that a two-phase bipolar type stepping motor is driven. The stepping motor 211 is connected to a motor driver (IC) 12 and rotates according to an excitation signal from the motor driver 12.

  The motor torque is set by varying the voltage at the Vref terminal of the motor driver. In FIG. 4, Vref is output from the CPU. Vref may be set by dividing the resistance.

  The motor driver 12 is provided with a SENSE terminal for detecting a current waveform flowing through the motor. The circuit 15 for inputting the voltage of the current detection resistor 14 to the CPU 105b makes it possible to recognize the rising state of the current flowing through the motor.

  More specifically, the SENSE terminal is used to detect the inflection point of the current flowing through the motor. By measuring the voltage of the current detection resistor 14 at predetermined time intervals, the current increase / decrease rate can be acquired. From the current increase / decrease rate, it is possible to obtain the presence or absence of an inflection point and the percentage of the set current at which the inflection point occurs.

  Further, by measuring the voltage of the current detection resistor 14 at a predetermined time interval, it is possible to determine at what sampling the inflection point is generated. For this reason, it is possible to grasp the time from the phase switching of the stepping motor until the inflection point occurs. Based on these pieces of information, it is recognized at which point the inflection point occurs.

  FIG. 5 is a diagram for explaining the transition of inflection point generation due to a load.

  5A to 5D, the graph shows the transition until the motor current reaches the constant current region (constant current chopping region).

  When the excitation signal is input and the motor coil current starts to flow, the motor current rises as shown in the figure. Although the current increase / decrease rate immediately after the excitation signal is input is small, the current increase rate gradually increases, and the current increase / decrease rate tends to decrease as the constant current region is approached. When the motor current rises to the set current, the motor current is repeatedly turned on and off to maintain the set current. In the waveform shown in FIG. 5, the current increase / decrease rate is a positive value, but the current may decrease depending on the motor and the load.

  In the present embodiment, the load on the motor is estimated by paying attention to a point where the current increase / decrease rate greatly changes (“inflection point”).

  When the load is light relative to the motor output (C in FIG. 5), the inflection point occurs at a point far from the constant current region. As the load is increased, the inflection point approaches the constant current control region (B in FIG. 5). When the load is further increased, an inflection point does not occur until the motor current reaches the constant current region (A in FIG. 5).

  If the load is further increased from this state, the time until the motor current reaches the constant current region is advanced as shown in FIG. This indicates a state in which the motor output with respect to the load is too small. In this case, motor output suitable for the load is not performed, and the motor is rotated in an unreliable state.

  Conventionally, a stepping motor sets a current in anticipation of a margin on the assumption that there is a change with time and a sudden change. Current setting that takes into account changes in load torque over time and sudden changes will be described with reference to FIGS.

  FIG. 6 is a diagram illustrating a load torque-time characteristic and a motor torque setting method.

  In the figure, the change over time of the load torque (a state where the load torque increases as time elapses) is shown by an oblique straight line. As shown in the “Conventional motor torque setting” line in FIG. 6, the motor current is set assuming that the motor torque is such that the motor rotates even when the maximum load torque is considered in the past. Was. For this reason, at the initial stage of the change with time, there is a problem that the current setting becomes excessive with respect to the load torque, and surplus power (surplus torque) is generated or the driving sound becomes large.

  In the present embodiment, as indicated by the stepped line of “motor torque setting of the present invention” in FIG. 6, when the power switch of the image forming apparatus is turned on or in an operation such as image stabilization processing, By detecting the inflection point, the load torque is periodically detected. Set an appropriate motor current according to the load torque.

  That is, in FIG. 6, the load torque is detected at the timing indicated by the upward arrow, and an appropriate motor current is set based on the detected load torque. Thus, it is possible to always set an appropriate current (torque) for the motor load.

  FIG. 7 is a diagram illustrating a load torque-time characteristic when there is a sudden change and a motor torque setting method.

  When the power switch is turned on or when the image stabilization process is performed, a part in which a load change occurs is intentionally operated without passing paper. FIG. 7 shows a state in which an electromagnetic clutch used for paper conveyance or the like is forcibly turned on without paper passing. In this case, the load torque suddenly increases as indicated by “electromagnetic clutch ON no paper” in the figure.

  At this time, the inflection point of the motor current is measured, and the load fluctuation amount is recognized from the change of the inflection point. A motor current (torque) is set based on the recognized load fluctuation amount.

  As indicated by “when electromagnetic clutch is turned on” in the figure, when the paper is passed, the load fluctuation due to the paper passing is added to the load fluctuation amount of only the electromagnetic clutch, and the load fluctuation occurs.

  When the electromagnetic clutch or the like is turned on based on the load fluctuation amount recognized during the initial operation or the image stabilization operation, an expected current that can correspond to the load is set in the motor. As a result, even if there is a sudden load fluctuation due to paper passing, feedback control can be performed without delay.

  In FIG. 7, the dotted line indicates the upper limit of the current setting. If the upper limit current is exceeded, the driver IC or the like will be damaged. In this case, the motor is stopped.

  As described above, according to the image forming apparatus of the present embodiment, it is possible to periodically detect temporal and sudden load fluctuations and to set the optimum and minimum current.

  FIG. 8 is a diagram for explaining a specific example of the inflection point detection method.

  When a motor current flows through the current detection resistor 14 shown in FIG. 4, a substantially similar voltage waveform appears at the SENSE terminal.

  In order to detect the inflection point, first, a linear function of current change from 0 V to the constant current control value is obtained (“linear linear function” in the figure). The constant current control value is obtained from the previous detection result of the inflection point.

  Now, let the obtained linear function be Y1 (n) = Atn.

  When actually performing motor control, the rising waveform of the voltage is sampled n times, and this result is defined as Y2 (n).

  By subtracting Y1 (n) from Y2 (n), it is possible to identify the 0 point or the place where the polarity of ± changes. The voltage value at this time is recognized as “inflection point 1”.

  If the “inflection point 1” is smaller than the target “inflection point A”, it is determined that the set current is large with respect to the load, and an instruction is output to lower the current set value as the next instruction.

  If “inflection point 1” is larger than the target “inflection point A”, it is determined that the set current is small with respect to the load, and control is performed to increase the current set value as the next instruction.

  An arithmetic expression for this control is described below as an example.

  I (next current setting value) = I (current current setting value) − (V (target inflection point A) −V (inflection point 1) × K1

  K1 indicates a current increase / decrease coefficient.

  If it is desired to set the safety factor to about 10% with respect to the current setting value, the target inflection point A may be divided by 1.1 to obtain the target inflection point.

  In addition, if the maximum / minimum fluctuation width of the inflection point is large as a result of sampling for a certain period of time, it is determined that the dynamic load fluctuation is large, and the current amplification factor may be set separately with the current increase / decrease coefficient K2. Good.

  An arithmetic expression for this control is described below as an example.

  I (next current set value) = I (current current set value) − (V (target inflection point A) −V (inflection point 1) × K1 × K2

  Further, when Y1 (n) is subtracted from Y2 (n), if only a point that becomes 0 appears, or if the polarity of ± does not change, there is no inflection point, so it may be determined that the step is out of step. .

  Whether the motor can rotate stably where the inflection point is relative to the load depends on the characteristics of the load, that is, whether there is a sudden load change during constant rotation, etc. To do.

  If the inflection point that actually occurs is closer to the constant current region than the inflection point position at the time of design, you can see that the load is heavier than the design value, so you can increase the motor setting current .

  Conversely, if the inflection point that occurs is far from the constant current region compared to the inflection point position at the time of design, it can be seen that the load is light relative to the design value, so the motor set current can be lowered. It ’s fine.

  The set current is fed back by the difference between the target inflection point position and the actual inflection point position obtained by the above method. As a result, it is possible to reduce excess energy by lowering the motor set current, and vibration suppression and energy saving can be achieved.

  The inflection point and the time until the start of constant current chopping have the following relationship.

  As shown in FIGS. 5C and 5B, when the motor is rotating with a light load, that is, with a surplus torque, the inflection point occurs on the side farther from the constant current region as the margin increases. The time from phase switching to the start of the constant current region is shortened.

  When the load increases (C → B in FIG. 5), that is, as the excess torque of the motor decreases, the inflection point approaches the constant current region, and the time from phase switching to the start of constant current increases.

  When the load becomes heavier (B → A in FIG. 5), that is, when the excess torque of the motor disappears, the current waveform shows a tendency for the bulge to reach the inflection point, and the motor current before the inflection point occurs. May reach a set current (constant current) and start constant current chopping.

  At this time, although the load is heavy, the time from phase switching to the start of the constant current region is shortened.

  If an inflection point occurs on the side close to the constant current region, if the setting change is made to increase the motor setting current, the inflection point will occur on the side far from the constant current region if the current setting change width is too large. There are two types of situations: a situation where the load is light relative to the motor output, and a situation where the inflection point cannot be confirmed before reaching the constant current range (the load is really heavy and the motor is in a state before the step-out). It is necessary to assume that this may occur.

  In order to identify these two types of situations, the past motor set current change contents are stored in the memory, and if the change to increase the set current has been repeated, the state before the step-out dimension is confirmed. It is desirable to be able to distinguish.

  In addition, after the excitation switching, it can be seen from the inflection point occurrence state at the motor set current and the inflection point occurrence state after the motor current setting change whether the motor output is appropriate for the actual load. By using this characteristic, it is possible to determine the risk of step-out and whether or not step-out has occurred.

  By leaving a history of repeated changes in which the load becomes heavy and the motor set current is increased, the load torque fluctuation transition is recorded.

  Since the upper limit value of the motor current that can be set is determined on the motor and the drive circuit, an inflection point may not occur even if the set current is increased. Even if there is no inflection point, the motor rotates, but this is not a state of rotating with an appropriate safety factor. In this case, it is possible to estimate the motor rotation state by measuring the time from phase switching to the start of the constant current region.

  When the load becomes heavier, the time from phase switching to the start of the constant current region is shortened. Further, this time is extremely shortened during step-out (D in FIG. 5). Using this characteristic, step-out determination and device control after determination can be performed.

  However, while the load becomes heavy in an abnormal state, if the current setting becomes infinitely large, a phenomenon such as breakage of the motor driver is caused. For this reason, it is desirable to set an upper limit of the current (FIG. 7) and stop the motor drive when the upper limit set value is exceeded.

  FIG. 9 is a flowchart illustrating motor current setting processing executed by the image forming apparatus.

  Referring to the figure, in step S101, a change with time of the current flowing through the motor is detected by sampling. In step S103, it is determined whether an inflection point exists in the motor current. If NO (state A or D in FIG. 5), it is determined in step S105 whether there is a history of increasing the set current in the past. judge.

  If “NO” in the step S105, an amount of increasing the current is calculated in order to increase the motor torque in a step S107. In step S108, the set current is increased based on the calculation result.

  If “YES” in the step S105, a time from when the current starts to flow until the set current is reached is measured in a step S111. In step S113, it is determined whether it is a predetermined time or more. If NO, step out (D in FIG. 5) is determined.

  If “YES” in the step S113, an amount to increase the current is calculated in order to increase the motor torque in a step S115. In step S117, the set current is increased based on the calculation result.

  If “YES” in the step S103, it is determined whether or not the inflection point is in an appropriate position in a step S119. If NO in step S119, it is determined in step S121 whether there is excess motor torque. If NO (a state between A and B in FIG. 5), the current is supplied to increase the motor torque in step S123. The amount to increase is calculated. In step S125, the set current is increased based on the calculation result.

  If YES in step S121 (state C in FIG. 5), in step S127, the amount by which the current is decreased to calculate the motor torque is calculated. In step S129, the set current is lowered based on the calculation result.

  If “YES” in the step S119, it is determined that the motor rotation is performed with an appropriate motor torque, and this routine is finished.

  FIG. 10 is a diagram showing the position of the stirring blade 207, and FIG. 11 is a diagram showing the stirring blade (load) torque for each position of the stirring blade 207 in FIG.

  As shown in FIG. 10, the stirring blade 207 rotates around the attachment shaft in the hopper portion 201. As a result, the stirring blade 207 moves from the position (1) to (6).

  When the stepping motor is driven by two-phase excitation, the stirring blade 207 is moved by 7.5 ° in one step. When the rotation angle from position (5) to position (1) is 105 °, stirring blade 207 can be moved from position (5) to position (1) in 14 steps.

  In the case of 1-2 phase excitation, since the stirring blade 207 is moved 3.75 ° in one step, the stirring blade 207 can be moved from position (5) to position (1) in 28 steps.

  FIG. 11 is a graph in which the position of the stirring blade 207 is taken on the horizontal axis and the stirring blade torque is taken on the vertical axis. The stirring blade torques for the positions (1) to (6) of the stirring blade 207 in FIG. 10 are t (1) to t (6).

  The stirring blade 207 supplies the toner 208 inside the hopper unit 201 to the buffer unit 202 during printing. As shown in FIG. 10, when the toner 208 is inside the hopper 201 and the stirring blade 207 is in each position (1) to (6), the load torque of the stirring blade 207 is as shown in FIG. .

  When the stirring blade is at the position (1), there is no load due to the toner 208, and the stirring blade 207 does not contact the wall of the hopper portion 201. At this time, since the stirring blade 207 rotates downward (gravity direction), the torque of the stirring blade 207 is the smallest of 360 °.

  When the stirring blade is at the position (2), since the stirring blade 207 is contained in the toner 208, torque for pushing the toner is required, and the torque of the stirring blade is increased.

  When the stirring blade is at position (3), since the stirring blade 207 is contained in the toner 208, the torque for pressing the toner is necessary, and the stirring blade 207 contacts the wall of the hopper 201. Therefore, a torque for overcoming this is also required. As a result, the torque of the stirring blade becomes the largest among 360 °.

  When the stirring blade is at the position (4), the stirring blade 207 is contained in the toner 208, and a torque for pushing the toner 208 is required, and the torque of the stirring blade is increased.

  When the stirring blade is at the position (5), there is no load by the toner 208, and the stirring blade 207 does not contact the wall of the hopper portion 201, but the stirring blade 207 rotates upward (antigravity direction). The torque of the stirring blade 207 at this time is slightly larger than (1).

  When the stirring blade is located at the position (6), the stirring blade 207 contacts the wall of the hopper portion 201, and thus a torque over this is necessary, and the torque is slightly increased.

  The magnitude of the torque with respect to each position of the stirring blade 207 is monitored during printing, and after the printing is finished, the stirring blade 207 is moved to the position (1) where the torque is lightest. Torque when starting to move can be reduced.

  In addition, when the stirring blade 207 is in the position (5) with respect to the position (1) where the torque of the stirring blade 207 is lightest, the torque is only large by the amount of gravity. Therefore, the stirring blade may be stopped at the position (5) (or any position where the stirring blade comes out of the toner and does not contact the wall) instead of the position (1) after the end of printing.

  However, in consideration of the time until the toner 208 is stirred, the stirring blade 207 can enter the toner 208 in a short time in the position (1) than in the position (5). . For this reason, if the stirring blade 207 after printing is moved to the position (1), the stirring time can be shortened slightly, but it is possible to contribute to energy saving.

  In FIG. 10, the stirring blade 207 may be moved to the position (1) and stopped in a state where the load at the start is least applied to the stirring blade 207, or the stirring blade 207 is not bent (the stirring blade 207). The stirring blade may be automatically adjusted and stopped at any position where the toner comes out of the toner and does not contact the wall.

  As a result, bending (creep phenomenon) of the stirring blade 207 can be prevented, and problems such as poor supply of the toner 208 due to bending of the stirring blade 207 and poor stirring of the toner 208 in the hopper 201 can be prevented. .

  FIG. 12 is a flowchart showing processing (stirring blade position control) for moving the stirring blade 207 to the position (1) in FIG.

  When the image forming apparatus executes printing in step S1, the load torque of the stirring blade 207 when the stirring blade 207 rotates during printing is monitored in step S2. In step S3, the position of the stirring blade 207 in FIG. 10 is grasped from the torque change state.

  In step S4, it is determined whether printing is completed. If NO (printing is not completed), the process returns to step S1 and printing is continued.

  If YES in step S4 (printing is completed), the position of the stirring blade 207 is determined from the torque change state before and after the end of printing (FIG. 11) in step S5, and the stirring blade is moved to the position (1). Let

  If the position of the stirring blade 207 is in the position (5) at the end of printing, the stirring blade is rotated at a rotation angle of 105 ° from the position (5) to the position (1), thereby causing the stirring blade to load torque. Is the lightest position (1).

  In this way, by determining the position of the stirring blade 207 from the change in the stirring blade torque until the end of printing and controlling the stepping motor, the stirring blade 207 can be moved to the position (1).

  [Effects of the embodiment]

  As described above, the image forming apparatus according to the present embodiment automatically sets the stirring blade to the position where the starting torque of the stirring blade becomes the lightest, thereby performing the optimum and minimum motor current automatic setting at the start of motor driving. be able to. Thereby, high efficiency and low noise of the stepping motor at the start of motor driving are realized. In addition, bending of the stirring blade can be prevented.

  [Others]

  The present invention can be implemented for an image forming apparatus such as an MFP, a facsimile machine, and a copying machine.

  Further, the processing in the above-described embodiment may be performed by software or by using a hardware circuit.

  In addition, a program for executing the processing in the above-described embodiment can be provided, and the program is recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, and a memory card and provided to the user. You may decide to do it. The program may be downloaded to the apparatus via a communication line such as the Internet.

  In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a diagram illustrating a configuration of an image forming apparatus according to one embodiment of the present invention. 2 is a diagram illustrating one configuration of developing devices 20Y, 20M, 20C, and 20K in the image forming apparatus. FIG. 1 is a block diagram illustrating a configuration of an information processing unit 100 of an image forming apparatus. It is a figure which shows the stepping motor drive circuit with which the control apparatus 105 is provided. It is a figure for demonstrating transition of the inflection point generation | occurrence | production by load. It is a figure which shows the setting method of a load torque-time characteristic and a motor torque. It is a figure which shows the setting method of the load torque-time characteristic when there is a sudden change, and a motor torque. It is a figure for demonstrating the specific example of the inflection point detection method. 5 is a flowchart illustrating motor current setting processing executed by the image forming apparatus. It is a figure which shows the position of the stirring blade 207. FIG. It is a figure which shows the stirring blade (load) torque with respect to each position of the stirring blade 207 in FIG. 11 is a flowchart showing a process (stirring blade position control) for moving the stirring blade 207 to the position (1) in FIG. 10.

Explanation of symbols

  12 motor driver IC, 105b CPU, 14 current detection resistor, 100 information processing unit, 102 image forming unit, 103 data input / output unit, 104 data communication control unit, 105 control device, 106 volatile memory, 107 stirring blade torque memory, 201 Hopper unit, 202 buffer unit, 203 supply roller, 204 developing roller, 205 photoconductor, 206 valve, 207 stirring blade, 208 toner, 211 stepping motor.

Claims (10)

A stirring member;
A motor for driving the stirring member;
An image forming apparatus comprising: an adjusting unit that adjusts a position of the stirring member so that the stirring member stops at a position where the starting torque becomes light. A stirring member;
A motor for driving the stirring member;
An image forming apparatus comprising: an adjusting unit that adjusts a position of the stirring member so that the stirring member stops at a position where the stirring member does not bend.   The image forming apparatus according to claim 1, wherein the motor is a stepping motor.   The adjusting means monitors the torque at the time of rotation of the stirring member to grasp the position of the stirring member at the end of printing, and adjusts the position of the stirring member by controlling the step of the stepping motor. The image forming apparatus according to claim 3, wherein the position of the stirring member is adjusted so that the member stops at a position where the starting torque is lightest. The adjusting means includes
An inflection point recognizing means for recognizing an inflection point from the rising state of the current flowing through the motor when grasping the torque during rotation of the stirring member;
Detection means for detecting a load fluctuation amount based on the inflection point recognized by the inflection point recognition means;
The image forming apparatus according to claim 4, further comprising a setting unit that automatically sets a current of the motor based on a load fluctuation amount detected by the detection unit.   The image forming apparatus according to claim 5, wherein the setting unit performs current setting based on a result recognized by the inflection point recognition unit and a current current setting value.   The image forming apparatus according to claim 5, wherein the result recognized by the inflection point recognition unit is sampled for a certain period of time, and the current is set based on the maximum and minimum shake widths.   The image forming apparatus according to claim 1, wherein the stirring member is a stirring blade for supplying toner. A stirring member;
A control method of an image forming apparatus provided with a motor for driving the stirring member,
A control method for an image forming apparatus, comprising: an adjusting step for adjusting a position of the stirring member so that the stirring member stops at a position where the starting torque becomes light. A stirring member;
A control method of a motor for driving the stirring member and an image forming apparatus,
A control method for an image forming apparatus, comprising: an adjustment step of adjusting a position of the stirring member so that the stirring member stops at a position where the stirring member does not bend.

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