JP2006017988A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable image forming apparatus making appropriate a driving means driving a fixing apparatus and in which apparatus size and cost are small. <P>SOLUTION: The image forming apparatus is provided with a stepping motor driving a paper ejecting roller and a pressure roller of the fixing apparatus which are rotated forward and in reverse, a photoreceptor drum and a DC brushless motor driving a transporting roller and a both sides transporting roller. Output of the stepping motor is connected to the pressure roller of the fixing apparatus 107 through a pendulum gear switching mechanism always rotated in a direction ejecting paper regardless of the forward rotation or the reverse rotation and output of the DC brushless motor is connected to the output of the stepping motor through a one way mechanism in the apparatus. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention comprises a motor capable of forward rotation only and a motor capable of forward / reverse rotation (hereinafter referred to as forward / reverse rotation motor), and has a function of performing duplex transport (double-sided printing) by forward / reversely rotating a paper discharge roller with a forward / reverse rotation motor. The present invention relates to a forming apparatus, and more particularly, to a driving configuration of the motor.

Conventionally, this type of electrophotographic printer is configured as shown in FIG.
Here, 1 is a photosensitive drum for forming an electrostatic latent image, 2 is a charging roller for uniformly charging the photosensitive drum 1, and 5 is an optical for scanning the laser beam on the photosensitive drum 1. A unit 6 is a laser beam emitted from the optical unit 5, 3 is a developing unit for developing an electrostatic latent image formed on the photosensitive drum 1 by the laser beam with toner, and 4 is a photosensitive drum 1. A transfer roller charger for transferring the toner image on a predetermined sheet, 7 a fixing unit for melting the toner on the sheet and fixing it on the sheet, 8 a standard cassette for loading sheets to be printed, 9 Is a standard cassette paper feed roller for picking up paper from the standard cassette 8, 10 is a manual feed tray, 11 is a manual paper feed roller, 12 is a first discharge roller for discharging paper out of the machine, and 12 'is a forward / reverse motor. Connected Only a normal rotation during single-sided continuous printing, a reversing roller for reversing and feeding the paper to a double-sided conveyance path to be described later, 13 for a double-sided printing, 13 a registration roller for taking the leading edge resist for printing the conveyed paper, 14 Is a TOP sensor sensor for detecting the leading edge of the paper, 15 is a paper discharge sensor for confirming whether the paper is normally discharged from the fixing device, 16 is a sensor for detecting the presence or absence of paper in the standard cassette 8, and 17 is the presence or absence of manual paper. , 18 and 19 are double-sided conveyance rollers for conveying a sheet for double-sided printing sent from the reversing roller 12 'at the time of reverse rotation of the forward / reverse rotation motor, and 20 is a sheet once conveyed at the time of double-sided printing. Stop the double-sided sensor that detects the leading edge of the paper in order to confirm the stop position for restarting the paper transport after receiving the print request for the second side of both sides. Sa.

  Conventionally, in such a configuration, each roller and the drive motor are connected as shown in FIG.

  That is, the paper feed roller, transport roller, photosensitive drum, double-sided transport roller, etc. are all connected to a DC brushless motor that rotates in a certain direction, and the paper feed roller is connected via a solenoid to turn on and off. Yes.

  Further, only the reversing roller for reversing is connected to a stepping motor capable of forward and reverse rotation.

  The double-sided conveyance roller needs to be temporarily stopped in order to wait for the print request on the second side of both sides, and is therefore connected to a solenoid for turning on and off.

  Generally, a fixing device requires an appropriate roller pressure to melt toner and fix it on a sheet, and therefore a load torque for rotating the toner tends to be relatively large. Even needed a lot of power. Further, since the toner is melted and fixed on the paper, the load fluctuation during rotation is large, and fine adjustment of the rotation speed is required. Furthermore, if the rotation speed of the fixing device is not properly controlled, the slack (loop) of the paper on which the toner is placed immediately before the fixing device is not appropriate, and the image may be deteriorated.

  As described above, the fixing device requires an appropriate roller pressure in order to melt and fix the toner on the paper, and therefore the load torque for rotation tends to be relatively large. Motors also require a large amount of power, greatly affecting the equipment size and cost. Also, since the toner is melted and fixed on the paper, the load fluctuation during rotation is large and fine adjustment of the rotation speed is necessary.If the rotation speed of the fixing device is not controlled properly, There is a problem that the slack (loop) of the loaded paper is not appropriate and the image deteriorates.

  The present invention has been made under such circumstances, and it is an object of the present invention to provide an image forming apparatus with high reliability by optimizing the driving means for driving the fixing device, reducing the size and cost of the apparatus. It is what.

  In order to solve the above problems, in the present invention, the image forming apparatus is configured as described in the following (1) to (7).

(1) An image forming apparatus comprising: a paper discharge roller that rotates forward and backward; a stepping motor that drives a pressure roller of a fixing device; and a DC brushless motor that drives a photosensitive drum, a conveyance roller, and a double-sided conveyance roller. ,
The output of the stepping motor is coupled to the pressure roller via a rotation direction switching means for always rotating the paper in the direction of discharging the paper regardless of whether it is forward rotation or reverse rotation, and the output of the DC brushless motor is the one-way mechanism An image forming apparatus coupled to the output of the stepping motor via

(2) In the image forming apparatus according to (1),
An image forming apparatus comprising control means for controlling to start the DC brushless motor before starting the stepping motor.

(3) A sheet feeding unit that feeds a sheet to be printed from a predetermined position and sends it to the conveyance path; and after forming an electrostatic latent image on the photosensitive drum according to image information, the electrostatic latent image is A toner image forming unit that visualizes with toner, a transfer unit that transfers a toner image formed by the toner image forming unit to a sheet fed to a conveyance path by the sheet feeding unit, and a sheet by the transfer unit. Fixing means for fixing the toner image transferred to the sheet onto the paper, discharging means for discharging the paper fixed by the fixing means to a predetermined position outside the apparatus, a fixing roller constituting the fixing means, and the fixing roller A first drive unit that drives a paper discharge roller that constitutes the discharge unit downstream of the second drive unit, a second drive unit that drives other than a conveyance system from the fixing roller to the paper discharge roller, and the paper discharge roller When rotating in the direction opposite to the paper discharge direction, A duplex conveying unit for feeding the photosensitive drum again receive paper, an image forming apparatus having a,
The first driving means can operate in three states of normal rotation, stop, and reverse rotation, the rotation speed can be finely adjusted from the driving source of the second driving means, and the fixing The roller has a rotation direction switching means for always rotating in the direction of discharging the paper regardless of the forward rotation or reverse rotation of the drive source,
The second driving means includes auxiliary driving means for driving the fixing roller and the paper discharge roller driven by the first driving means via a gear train having a predetermined reduction ratio and a one-way mechanism from the driving source. Have
Further, the first driving means starts driving by the second driving means, and then satisfies the predetermined condition, and then starts driving the first driving means and the first driving means. An image forming apparatus comprising: a drive state detection unit that detects a rotation state of the unit; and a drive control unit that instructs to drive / stop / redrive the first drive unit based on information from the drive state detection unit.

(4) In the image forming apparatus according to (3),
The predetermined condition is that the temperature of the fixing device satisfies a predetermined temperature requirement after the second driving unit starts driving and temperature control of the fixing device is started.

(5) In the image forming apparatus according to (3),
The predetermined condition is that the predetermined time requirement is satisfied after the second driving unit starts driving and temperature control of the fixing device is started.

(6) In the image forming apparatus according to (4),
The driving state detection unit is an image forming apparatus that detects a driving state of the first driving unit from a temperature rise characteristic of the fixing device after the driving of the first driving unit is started.

(7) In the image forming apparatus according to (5),
The drive state detection unit is an image forming apparatus that detects the drive state of the first drive unit from the energization power characteristic of the fixing device after the drive of the first drive unit is started.

  According to the present invention, since the fixing device is driven by the first driving source that can easily finely adjust the rotational speed, for example, a stepping motor, there is no image deterioration due to inappropriate rotational speed in the fixing device. Since the second drive source, for example, the DC brushless motor, does not need to drive a fixing device having a large load torque, the size can be reduced. In addition, since the output of the second drive source is coupled to the output of the first drive source, and the second drive source is activated prior to activation of the first drive source, the first drive source is activated. The torque can be reduced and the size can be reduced. As a result, the reliability of the image forming apparatus can be improved and the size and price of the apparatus can be optimized.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

FIG. 1 is a cross-sectional view of a mechanism portion of a “printer” that is Embodiment 1.
Here, 101 is a photosensitive drum for forming an electrostatic latent image, 102 is a charging roller for uniformly charging the photosensitive drum 101, and 105 is an optical for scanning the laser beam on the photosensitive drum 1. A unit 106 is a laser beam emitted from the optical unit 105, 103 is a developing unit for developing the electrostatic latent image formed on the photosensitive drum 101 by the laser beam with toner, and 104 is a photosensitive drum 101. A transfer roller charger for transferring the toner image on a predetermined sheet, 107 a fuser for melting the toner on the sheet and fixing it on the sheet, 108 a standard cassette for loading sheets to be printed, 109 Is a standard cassette feed roller that picks up paper from the standard cassette, 110 is a manual feed tray, 111 is a manual feed roller, and 112 is for ejecting paper out of the machine. The first discharge roller 112 ′ rotates only in the discharge direction during single-sided continuous printing and discharges the paper.At the time of double-sided printing, the paper is discharged to a predetermined position in order to send the paper to the double-sided conveyance unit. This is a second discharge roller that can be rotated in the reverse direction so that the sheet is fed to the double-sided conveyance unit, and also has a reverse function.

  113 is a registration roller for registering the leading edge for printing the conveyed paper, 114 is a TOP sensor for detecting the leading edge of the paper and measuring the length of the paper being conveyed, and 115 is for normally fixing the fixing device 107 to the paper. A paper discharge sensor for confirming whether or not the discharge is completed, 116 is a sensor for detecting the presence / absence of paper in the standard cassette, 117 is a sensor for detecting the presence / absence of manual paper, and 118 is for canceling the double feed of the fed paper. A retard roller 119, a conveyance roller for feeding the fed and separated printing paper to the registration unit, 120 a first double-sided conveyance roller for feeding the sheet reversed by the reversing roller 112 'to the duplex conveyance unit, Reference numeral 121 denotes a second double-sided conveyance roller for feeding from the double-sided conveyance unit to the registration unit. Reference numeral 122 denotes a sheet fed from the reversing roller 112 ′ to the first both-side conveyance roller. At a predetermined position before the transport rollers 120, a double-sided inversion sensor for detecting a position to wait for a print request waiting.

  FIG. 2 is a block diagram showing the printer control unit in the printer of this embodiment. Reference numeral 301 denotes communication with the host computer, reception of image data, development of the received image data into information that can be printed by the printer, and exchange of signals and serial communication with a printer engine control unit to be described later. A printer controller 302 performs an exchange of signals with the printer controller 301 and an engine control unit that controls each unit of the printer engine via serial communication.

  A serial communication command / status line 303 between the controller 301 and the engine control unit 302 has a bidirectional function. 304 is a serial synchronization clock for transferring the command status, 305 is a vertical synchronization signal indicating to the controller 301 that a sheet has been conveyed and the sensor has reached the TOP sensor 114 / TOP signal, and 306 for image output. The / BD signal, 307, which is a horizontal synchronizing signal, is an image signal.

  A sheet conveyance control unit 308 feeds and conveys a sheet to be printed and performs sheet conveyance until printing after printing based on an instruction from the engine control unit 302. 309 denotes a TOP sensor 114, a sheet discharge sensor 115, and a sheet presence sensor 116. 117 is a paper presence / absence sensor input unit that transmits the state of each sensor 117 to the engine control unit 302, 310 is a jam detection unit that detects paper jam based on an instruction from the engine control unit 302, and 311 is a scanner motor drive and laser. The optical system control unit 312 executes ON / OFF control based on an instruction from the engine control unit 302, and 312 performs a high voltage output necessary for an electrophotographic process such as charging, development, and transfer based on an instruction from the engine control unit 302. A system control unit 313 controls the temperature of the fixing device 107 based on an instruction from the engine control unit 302 and fixes Fixing temperature control section performs abnormality detection of 107, 314 is a failure detecting section detecting a failure of the function of the printer.

  The sheet conveyance control unit 308 (FIG. 2) controls two types of motors as shown in FIG. First, the motor is composed of two motors: a DC brushless motor 401 that drives a paper feed system, a registration unit, a drum system, and a double-sided transport system, and a stepping motor 402 that drives a fixing system and a paper discharge / reversing system. . Further, the DC brushless motor 401 is connected to a drive train to a stepping motor 402 through a predetermined reduction gear 404 and a One Way roller 405. The One Way roller 405 is rotated after releasing the driving from the DC brushless motor 401 during the period when the driving by the stepping motor 402 is rotating at a high speed, and the driving from the DC brushless motor 401 is faster. This is a roller having a function of generating torque for the drive train on the stepping motor side only in this case.

  The feed rollers 109 and 111 are connected to the DC brushless motor 401 via solenoids because they must be stopped in a predetermined time. The other rollers connected to the DC brushless motor 401 are rollers that always rotate in a constant rotation direction when the DC brushless motor 401 is driven.

  On the other hand, since the fixing roller system connected to the stepping motor 402 rotates in a certain direction even when both sides are reversed, the pendulum gear connected to the pendulum gear 403 is connected with the rotation direction of the stepping motor 402. It is an element capable of switching the gear train, and the fixing system roller connected thereto always rotates in a fixed direction, that is, in the direction of discharging the paper regardless of the rotation direction of the stepping motor 402. Further, since the paper discharge roller 112 'is connected to the stepping motor 402 via a normal gear train, it is configured to rotate forward and backward as the stepping motor rotates forward and backward.

  FIG. 4 is a diagram illustrating the configuration of the pendulum gear in detail. A paper discharge roller is connected to a stepping motor 402 (not shown) through three stages of gears. On the other hand, the pressure roller is connected through a pendulum gear on the way, and is configured to be connected to the gear A or the gear B based on the rotation direction of the stepping motor 402. In addition, a gear train from a DC brushless motor 401 (not shown) which is a main motor is connected to a drive system of the stepping motor 402 via a One Way mechanism.

  FIG. 5 is a flowchart illustrating how the driving of the fixing device 107 is specifically controlled in the configuration of the control unit as described above. First, in step 1 (abbreviated as S1 in the figure, the same applies hereinafter), the printer control unit 302 transitions to a waiting state for a print request from the printer controller 301. When a print request from the printer controller is received from this state, the driving of the DC brushless motor is started (step 2). The DC motor failure detection timer Tm is started (step 3), then the process proceeds to step 4 and after the DC brushless motor starts to start, the DC brushless motor reaches a predetermined rated rotational speed based on the rotational speed information output from the DC brushless motor. Determine if you did. After determining that the DC brushless motor has reached the rated rotation speed, the process proceeds to step 5 and step 6 to start energization to the fixing heater. At this time, since only the DC brushless motor is driven, the fixing device is in a low-speed rotation state based on a predetermined reduction ratio, and energization to the heater is started from this state. Start energizing in a fixed state.

  The process proceeds to step 7 and the timer Tr starts counting in order to detect the initial value of the fixing heater at the time of starting energization and the time from the initial value until a predetermined temperature difference ΔT ° C. rises in temperature by the measurement timer Tr. The process proceeds to step 8, waits for a predetermined target temperature difference to be reached, and then proceeds to step 9, and when the rising time Tr is detected, the value is stored in the Tr1 memory.

  Step 10 is started to start the stepping motor, and then step 11 is started. At the same time, the time until the heater temperature further rises by ΔT ° C. from the temperature at that time is also started to be measured by the measurement timer Tr. The process waits for ΔT ° C. rise, and the process proceeds to step 13 where the measurement result of the measurement timer Tr is stored in Tr2. When the above control is completed, the routine proceeds to step 14, where the timer measurement values of Tr1 and Tr2 are compared, and Tr2 is larger than Tr1 by a predetermined value T0 or more, that is, the rising gradient of the heater temperature is gentle as a result of starting the stepping motor. If it is determined that the stepping motor has started, it is determined that the stepping motor has started up normally without stepping out, and an electrophotographic process (photosensitive drum high-pressure application process) for printing operation is started (step 15). , 16, 17) When the fixing heater temperature reaches a predetermined temperature (step 18), the paper feeding operation is started (step 19).

  On the other hand, if it is determined in step 14 that the difference in the temperature gradient of the fixing heater after starting the stepping motor is smaller than a predetermined value, it is determined that the stepping motor has stepped out and the stepping motor starting process is performed again. Control is performed (step 20).

  If the failure detection timer Tm finishes counting before the DC brushless motor reaches the predetermined number of revolutions (steps 4 and 21), it is determined that the DC brushless motor has failed, and the process proceeds to step 22 to perform failure processing.

  FIG. 6 schematically shows the temperature transition of the fixing heater in the start-up process. When the stepping motor is rotating normally, the temperature rise curve becomes smooth because the energizing power is kept constant despite the increase in heat dissipation after the stepping motor starts up and the heat of the fixing device increases. On the other hand, when the stepping motor steps out, it draws the same temperature rise curve as before, so as shown by the broken line in the figure, the time until ΔT ° C rises is much shorter than when the stepping motor is rotating normally. Become. As described above, by monitoring the temperature rise characteristic of the fixing heater, it is possible to predict the rotation state of the stepping motor that drives the fixing device, and to greatly improve the reliability of the printer.

  As described above, according to the present embodiment, the fixing device is driven by the stepping motor that allows easy adjustment of the rotational speed, so that there is no deterioration of the image due to inappropriate rotational speed of the fixing device. Since the DC brushless motor does not need to drive a fixing device having a large load torque, it can be miniaturized. Also, since the output of the DC brushless motor is combined with the output of the stepping motor and the DC brushless motor is started prior to the start of the stepping motor, the stepping motor startup torque can be small, and the stepping motor can be downsized. Become. As a result, the reliability of the image forming apparatus can be improved and the size and price of the apparatus can be optimized.

  A “printer” according to the second embodiment will be described. In this embodiment, after the driving of the DC brushless motor is started, the normal rotation / step-out of the stepping motor is identified from the energized power for keeping the temperature of the fixing heater constant.

  Since the configuration of the main body, the configuration of the motor drive system, and the like are the same as those of the first embodiment, the description thereof will be omitted, and the processing of this embodiment will be described with reference to the flowchart of FIG.

  First, the printer control unit transitions to a waiting state for a print request from the printer controller (step 31). When a print request from the printer controller is received from this state, the process proceeds to step 32 to start driving the DC brushless motor. The process proceeds to step 33, and counting of the DC brushless motor failure detection timer Tm is started. Moving to step 34, after starting the DC brushless motor, it is determined whether or not the DC brushless motor has reached a predetermined rated rotational speed based on the rotational speed information output from the DC brushless motor. After determining that the DC brushless motor has reached the rated rotational speed, energization of the fixing heater is started (step 35). The target temperature at a temperature considerably lower than the temperature for printing in the fixing heater is set to Tm, and fixing temperature control is started (steps 35 and 36). First, the fixing heater is set to the target temperature Tm during low-speed rotation of only the DC brushless motor. Wait until it reaches (step 37). After the fixing heater reaches the target temperature Tm, the average power measurement timer ta starts counting (step 38), and the power supplied to the heater energized during the ta period is sampled (step 39). The average value of the sampled power is stored in the memory as W1 (steps 40 and 41). Thereafter, the stepping motor is started (step 42). After starting the stepping motor, the power supplied to the fixing heater during the ta period is sampled as described above (step 44), and the average power during the ta period is stored in the memory as W2 (steps 45 and 46). Then, these average energized powers W1 and W2 are compared (step 47), and if it is determined that W2 is larger than the predetermined power compared to W1, it is determined that the stepping motor is rotating normally, If it is determined that the power is not greater than the predetermined power, it is determined that the stepping motor has stepped out, and the stepping motor is restarted (step 56).

  FIG. 8 schematically shows the temperature transition at the start-up. During the low speed rotation only for driving the DC brushless motor before starting the stepping motor, the energization power for maintaining the fixing heater temperature at the target Tm ° C. is relatively small. However, when the stepping motor is driven, the electric power necessary to maintain the target temperature increases because of high speed rotation. On the other hand, when the stepping motor steps out, the power change does not appear so much. In this embodiment, the difference in power is detected from the average powers W1 and W2 at time ta. Here, a description is added of a method of measuring the energization power to the fixing heater.

  FIG. 9 shows a part of the fixing heater driving circuit and its control system in this embodiment.

  The AC input is divided into two systems: a fixing heater driving circuit, a low-voltage power supply, and a zero cross detection circuit.

  The fixing heater driving circuit energizes the heater 92 via the triac 91 after a predetermined time from the zero cross every half cycle of the AC waveform by the FSRD signal output from the CPU of the engine control unit. A thermistor 93 for detecting the temperature of the fixing heater is attached in the vicinity of the heater 92. The temperature-resistance characteristic of the thermistor 93 is converted into an analog voltage level by a pull-up resistor 94, and then an A / D input of the CPU. Connected to the terminal. The low-voltage power supply circuit also has an AC waveform zero-cross detection circuit that converts the AC sine waveform to a rectangular wave and captures the rising and falling edges of the AC waveform into the interrupt terminal of the CPU to recognize the zero-cross timing. ing. The CPU determines the power to be energized, that is, the FSRD output timing ton (FIG. 10) for turning on the fixing heater from the zero cross, from the temperature information from the A / D input and the information on the difference between the target temperatures.

  FIG. 10 is a timing chart showing the operation of the fixing heater driving circuit. From the top, the AC waveform, the zero cross waveform, the FSRD signal waveform, and the energization phase of the triac 91 are shown.

  As described above, the determination of whether the stepping motor is rotating normally or out of step can be detected from the change in the energized power.

  As described above, according to the present embodiment, the same effects as those of the first embodiment can be obtained.

The figure which shows the structure of Example 1. Diagram showing the configuration of the printer controller Diagram showing motor drive configuration Diagram showing gear configuration The figure which shows the process in Example 1. Schematic diagram showing motor startup processing The figure which shows the process in Example 2. Schematic diagram showing motor startup processing The figure which shows a part of fixing heater drive circuit and its control system Timing chart showing operation of fixing heater drive circuit Diagram showing the configuration of a conventional example The figure which shows the drive structure of the motor in a prior art example

Explanation of symbols

107 Fixing Device 401 DC Brushless Motor 402 Stepping Motor 403 Pendulum Gear 404 One Way Mechanism

Claims (7)

A stepping motor that drives a forward and reverse paper discharge roller and a pressure roller of the fixing device;
A DC brushless motor that drives a photosensitive drum, a conveyance roller, and a double-sided conveyance roller;
The output of the stepping motor is coupled to the pressure roller through a rotation direction switching means for always rotating the paper in the direction of discharging the paper regardless of forward rotation or reverse rotation, and the output of the DC brushless motor is a one-way mechanism. The image forming apparatus is coupled to an output of the stepping motor via The image forming apparatus according to claim 1.
An image forming apparatus comprising control means for controlling to start the DC brushless motor before starting the stepping motor. A sheet feeding unit that feeds a sheet to be printed from a predetermined position and sends it to the conveyance path, and after forming an electrostatic latent image on the photosensitive drum according to the image information, the electrostatic latent image can be formed with toner. A toner image forming means for visualizing; a transfer means for transferring a toner image formed by the toner image forming means to a paper fed to a conveyance path by the paper feeding means; and a transfer means for transferring the toner image to the paper. A fixing means for fixing the toner image on the paper, a discharging means for discharging the paper fixed by the fixing means to a predetermined position outside the apparatus, a fixing roller constituting the fixing means, and a downstream of the fixing roller. A first driving unit that drives a paper discharge roller constituting the discharge unit; a second driving unit that drives a part other than a conveying system from the fixing roller to the paper discharge roller; and the paper discharge roller is in a paper discharge direction When the paper is rotated in the opposite direction, A duplex conveying unit for feeding the photosensitive drum again taken only, an image forming apparatus having a,
The first driving means can operate in three states of normal rotation, stop, and reverse rotation, the rotation speed can be finely adjusted from the driving source of the second driving means, and the fixing The roller has a rotation direction switching means for always rotating in the direction of discharging the paper regardless of the forward rotation or reverse rotation of the drive source,
The second drive means includes an auxiliary drive means for driving the fixing roller and the paper discharge roller driven by the first drive means via a gear train having a predetermined reduction ratio and a one-way mechanism from the drive source. Have
Further, the first drive means starts driving by the second drive means, and then starts driving the first drive means after satisfying a predetermined condition, and the first drive Drive state detecting means for detecting the rotation state of the means, and drive control means for instructing driving / stopping / re-driving of the first drive means based on information from the drive state detecting means. Image forming apparatus. The image forming apparatus according to claim 3.
The predetermined condition is that the temperature of the fixing unit satisfies a predetermined temperature requirement after the second driving unit starts driving and starts temperature control of the fixing unit. apparatus. The image forming apparatus according to claim 3.
The image forming apparatus according to claim 1, wherein the predetermined condition is that a predetermined time requirement is satisfied after the second driving unit starts driving and temperature control of the fixing device is started. The image forming apparatus according to claim 4.
The image forming apparatus, wherein the driving state detecting unit detects a driving state of the first driving unit from a temperature rise characteristic of the fixing device after the driving of the first driving unit is started. The image forming apparatus according to claim 5.
The image forming apparatus according to claim 1, wherein the driving state detecting unit detects a driving state of the first driving unit from an energization power characteristic of the fixing device after the driving of the first driving unit is started.