JP2021004938A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that can quickly stop a motor while recovering a regenerative energy.SOLUTION: An image forming apparatus fixes a toner image transferred to a sheet with a fixing unit 109. The fixing unit 109 comprises a fixing roller 301 and a pressure roller 302. The fixing roller 301 is driven to rotate by a fixing motor 500. The fixing motor 500 is driven by a motor driving unit 501. The motor driving unit 501 is controlled by a motor control unit 256. At the occurrence of an abnormality not caused by the fixing unit 109, the motor control unit 256 stops the fixing motor 500 while recovering a regenerative energy from the fixing motor 500 and storing the energy in an electricity storage unit 503. At the occurrence of an abnormality caused by the fixing unit 109, the motor control unit 256 stops the fixing motor 500 in a short time compared with a case where it stops the motor while recovering the regenerative energy.SELECTED DRAWING: Figure 4

Description

The present invention relates to an electrophotographic image forming apparatus such as a printer or a copier.

The image forming apparatus includes a fixing device for fixing the toner image on the paper. The fixing roller included in the fixing device is driven by various types of motors such as a brushless DC motor and a stepping motor. In general, motors pursue efficiency at rated loads, and are not efficient at light loads. For example, when the motor that drives the fuser is stopped, the fuser is in a non-operating state. In this case, since the fuser has a low load, the efficiency of the motor is low and the heat loss increases. That is, energy is discarded as heat.
On the other hand, a technology has been proposed in which the motor is regenerated when the motor is decelerated or stopped, and the regenerative energy is stored in a capacitor or other storage device to recover the energy discarded as heat loss (patented). Document 1).

As the braking operation of the motor, either "short brake" or "reverse brake" is adopted. In the short brake, the motor winding is short-circuited, and while the resistance of the motor winding consumes rotational energy, braking control is performed by the torque generated by the electromagnetic induction effect. The reverse brake performs a control operation by controlling the winding current with a semiconductor element so that a reverse rotation torque is generated (Non-Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-278348

Koji Hagino, "How to Use Brushless DC Motor", published by Ohmsha, p. 103

When the power supply to the motor is stopped and the motor is stopped only by the inertia of the load, the time required for the motor to stop (stop time) is relatively long, so the regenerative energy can be efficiently used during the stop time. It can be collected in a capacitor.
However, when the configuration for storing the regenerative energy in the capacitor is applied to the motor for driving the fixing roller, the following problems may occur. Specifically, when paper jam occurs near the fuser, if the power supply to the motor is stopped and the motor is stopped only by the inertia of the load, the jam paper is wrapped around the fixing roller and the jam paper is concerned. Can be difficult to remove. Therefore, in order to prevent the jam paper from wrapping around the fixing roller, the rotation of the fixing roller needs to be stopped immediately. That is, since the stop time of the motor that drives the fixing roller is short, the regenerative energy cannot be efficiently recovered in the capacitor.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of quickly stopping a motor while recovering regenerative energy.

The image forming apparatus of the present invention includes an image forming means for forming an image on an image carrier, a transfer means for transferring an image from the image carrier to paper, and a first roller and a second roller. A fixing means for fixing the image on the paper by sandwiching and transporting the transferred paper between the first roller and the second roller, a motor for rotationally driving the first roller, and driving the motor. The drive means is provided, a control means for controlling the drive means to control the drive of the motor, and a storage means, and the control means regenerates from the motor when an abnormality not caused by the fixing means occurs. The motor is stopped while recovering the energy and stored in the power storage means, and when an abnormality caused by the fixing means occurs, the motor is stopped in a shorter time than when the regenerated energy is recovered and stopped. It is a feature.

According to the present invention, it is possible to quickly stop the motor while recovering the regenerative energy.

The block diagram of the image forming apparatus. Explanatory drawing of the controller. (A) and (b) are explanatory views of a fuser. Explanatory drawing of the drive mechanism of a fixing roller. Explanatory drawing of short brake operation. Explanatory drawing of control at the time of stopping of a fixing motor. The flowchart which shows the process at the time of the stop operation of a fixing motor.

A preferred embodiment of the present invention will be described below with reference to the drawings.

(overall structure)
FIG. 1 is a configuration diagram of an image forming apparatus of the present embodiment. The image forming apparatus 1 of the present embodiment forms a color image in which images of each color of yellow (Y), magenta (M), cyan (C), and black (K) are superimposed on the paper P. Therefore, the image forming apparatus 1 includes image forming units 100a, 100b, 100c, 100d, an intermediate transfer belt 107, a paper cassette 111, a paper feeding transport unit 130, a secondary transfer unit 108, a fixing device 109, and a fixing device 109 corresponding to each color. A paper ejection transport unit 131 is provided.

The image forming portions 100a, 100b, 100c, and 100d have the same configuration, and only the colors of the formed images are different. The image forming portions 100a to 100d include photosensitive drums 101a to 101d which are image carriers. The photosensitive drums 101a to 101d can be rotated in the direction of arrow R in the drawing. Around the photosensitive drums 101a to 101d, chargers 102a to 102d, laser scanning units 103a to 103d, developing machines 104a to 104d, primary transfer rollers 105a to 105d, and drum cleaners 106a to 106d are provided.

The surface of the photosensitive drums 101a to 101d is uniformly charged by the chargers 102a to 102d during rotation. The laser scanning unit 103a to 103d has a semiconductor laser as a light source, and irradiates the charged surface of the photosensitive drums 101a to 101d with the laser. The laser scanning units 103a to 103d form an electrostatic latent image corresponding to the image on the surface of the photosensitive drums 101a to 101d by irradiating the laser based on the image data representing the image to be formed.

The developing devices 104a to 104d develop the electrostatic latent image formed on the photosensitive drums 101a to 101d. The developer 104a develops an electrostatic latent image of the photosensitive drum 101a to form a yellow toner image on the surface of the photosensitive drum 101a. The developer 104b develops an electrostatic latent image of the photosensitive drum 101b to form a magenta toner image on the surface of the photosensitive drum 101b. The developing device 104c develops an electrostatic latent image of the photosensitive drum 101c to form a cyan toner image on the surface of the photosensitive drum 101c. The developer 104d develops an electrostatic latent image of the photosensitive drum 101d to form a black toner image on the surface of the photosensitive drum 101d.

The toner images of each color are sequentially transferred to the intermediate transfer belt 107 in the primary transfer portion where the primary transfer rollers 105a to 105d to which a high voltage is applied and the photosensitive drums 101a to 101d are rubbed via the intermediate transfer belt 107. .. The toner remaining on the photosensitive drums 101a to 101d after the transfer is removed by the drum cleaners 106a to 106d.

The intermediate transfer belt 107 is an endless image carrier, passes between the photosensitive drums 101a to 101d and the primary transfer rollers 105a to 105d, and is wound around the rollers constituting the secondary transfer unit 108. The intermediate transfer belt 107 is rotatable in the direction of arrow V, and a toner image is superimposed and transferred from each photosensitive drum 101a to 101d at a timing corresponding to the rotation to carry a full-color toner image. The full-color toner image is conveyed to the secondary transfer unit 108 by the rotation of the intermediate transfer belt 107.

Paper P is conveyed to the secondary transfer unit 108 according to the timing at which the toner image is conveyed by the intermediate transfer belt 107. The paper P is housed in the paper feed cassette 111, and is fed to the paper feed transport unit 130 according to the timing of image formation. The paper feed transport unit 130 includes a plurality of roller pairs, and the fed paper P is sandwiched and transported to the secondary transfer unit 108 by the plurality of roller pairs.

The secondary transfer unit 108 collectively transfers the four-color toner images formed on the intermediate transfer belt 107 to the paper P. The secondary transfer unit 108 includes two rollers, and when a high voltage is applied, the toner image is transferred from the intermediate transfer belt 107 to the paper P. The toner remaining on the intermediate transfer belt 107 after transfer is removed by a belt cleaner 112 provided in the vicinity of the intermediate transfer belt 107.

The paper P on which the toner image is transferred is conveyed from the secondary transfer unit 108 to the fixing device 109. The fixing device 109 includes a fixing roller 301 and a pressure roller 302. The fixing device 109 fixes the unfixed toner image on the paper P by heating and pressurizing it with the fixing roller 301 and the pressing roller 302. The paper P is sandwiched and conveyed between the fixing roller 301 and the pressure roller 302 to perform the image fixing process. As a result, the image is fixed on the paper P and the product is completed. After the image is fixed, the paper P is discharged to the paper output tray 110 via the paper discharge transport unit 131.

FIG. 2 is an explanatory diagram of a controller that controls the operation of the image forming apparatus 1. The controller 201 includes a system controller 251, an A / D converter 252, a high voltage control unit 254, a motor control unit 256, a DC load control unit 257, sensors 258, and an AC driver 259. The image processing unit 202 and the operation unit 280 are connected to the system controller 251. The image processing unit 202 performs predetermined processing on the image data. The operation unit 280 is a user interface.
The system controller 251 is connected to the A / D converter 252, the high voltage control unit 254, the motor control unit 256, the DC load control unit 257, the sensors 258, and the AC driver 259. The A / D converter 252 is connected to the thermistor 253 provided in the fuser 109. The high voltage control unit 254 is connected to the high voltage unit 255. The AC driver 259 is connected to a fixing heater 260 provided in the fixing device 109.

The system controller 251 comprehensively controls the operation of the image forming apparatus 1. The system controller 251 mainly drives each load provided inside the image forming apparatus 1, analyzes the detection result by the sensors 258, and exchanges data with the operation unit 280. The system controller 251 is a computer including a CPU (Central Processing Unit) 270, a ROM (Read Only Memory) 271, and a RAM (Random Access Memory) 272. The CPU 270 controls the operation of the image forming apparatus 1 by executing the computer program stored in the ROM 271 using the RAM 272 as the work area. In the RAM 272, for example, a high voltage set value for the high voltage control unit 254, various data described later, image formation command information from the operation unit 280, and the like are stored.

The system controller 251 transmits the specification setting value data of each unit to the image processing unit 202. The system controller 251 receives a signal such as a document image density signal from each unit, and controls the high-voltage control unit 254 and the image processing unit 202 to make settings for performing optimum image formation. The system controller 251 acquires information such as a copy magnification and a density setting value set by the user from the operation unit 280. The system controller 251 transmits to the operation unit 280 data for presenting the state of the image forming apparatus 1, for example, information on the number of images formed, whether or not an image is being formed, the occurrence of a jam, its location, and the like to the user. To do. The system controller 251 and the operation unit 280 exchange various settings for the tab paper and display a warning for the tab paper.

The image forming apparatus 1 is internally arranged with a DC load such as a motor, a clutch / solenoid, and sensors 258 (photo interrupter, microswitch, etc.). The image forming apparatus 1 conveys the paper P and drives each unit by appropriately driving the motor and each DC load. The sensors 258 are used to monitor the motor, each DC load, the paper P, and the drive of each unit. The system controller 251 causes the motor control unit 256 to control each motor based on the monitoring result using the sensors 258, and the DC load control unit 257 to control the DC load to smoothly perform the image forming operation. The system controller 251 transmits various high-voltage control signals to the high-voltage control unit 254 to apply an appropriate high voltage to the high-voltage unit 255. The high-voltage unit 255 is a charger 102, a developing device 104, a primary transfer roller 105, and a secondary transfer unit 108.

The fixing heater 260 is provided on each of the fixing roller 301 and the pressurizing roller 302 of the fixing device 109 for heating the toner image. The thermistor 253 measures the internal temperature of the fuser 109 heated by the fixing heater 260. The system controller 251 acquires the temperature detected by the thermistor 253 via the A / D converter 252, and controls the temperature of the fixing heater 260 by the AC driver 259 according to the detected temperature. The AC driver 259 controls the amount of heat generated by the fixing heater 260 by controlling the on / off of the AC driver 259 and controlling the energization of the fixing heater 260. The thermistor 253 has a built-in variable resistor. The resistance value of the variable resistor changes according to the temperature change inside the fuser 109. The change in resistance value is input to the A / D converter 252 as a change in the voltage value of the thermistor 253. The A / D converter 252 converts the change in the voltage value into a digital value and inputs it to the system controller 251 as the detected temperature.

(Fixer)
FIG. 3 is an explanatory diagram of the fuser 109. In FIG. 3, the fuser 109 includes a thermistor 253, a fixing roller 301, a pressurizing roller 302, a heat roller 303 as a fixing heater 260, an inlet sensor 401, and an outlet sensor 402. The inlet sensor 401 detects that the paper P has entered the fuser 109. The exit sensor 402 detects that the paper P has passed through the fuser 109. The pressurizing roller 302 has a built-in fixing heater (not shown).

FIG. 3A is a diagram showing paper P1 that has been normally conveyed. The paper P passes through the detection position of the inlet sensor 401, is conveyed while being nipated by the fixing roller 301 and the pressurizing roller 302, and passes through the detection position of the outlet sensor 402 (paper P1). In this case, the exit sensor 402 detects the paper P1 within a predetermined time after the inlet sensor 401 detects the paper P1. However, as shown in FIG. 3B, the paper P may stick to the fixing roller 301 due to the toner of the paper P functioning as an adhesive (paper P2). The state in which the paper P2 is wound around the fixing device 109 in this way is referred to as “fixing winding”. When the fixing wrapping occurs, the outlet sensor 402 does not detect the paper P even if a predetermined time elapses after the inlet sensor 401 detects the paper P. The system controller 251 can determine the occurrence of jam (fixation wrapping) inside the fuser 109 based on the detection results (difference in detection timing) of the inlet sensor 401 and the outlet sensor 402.

In a fixed winding state such as the paper P2, it is difficult for the user to easily remove the paper P2, and usability is deteriorated. In order to prevent the paper P from being caught in the depth of the fixing roller 301, it is necessary to shorten the distance between the inlet sensor 401 and the outlet sensor 402 to detect the fixing wrapping at an early stage or to stop the fixing roller 301 suddenly. There is. However, it is difficult to arrange the inlet sensor 401 and the outlet sensor 402 with a reduced distance because the temperature of the fixing roller 301 and the pressure roller 302 is controlled at a high temperature. Therefore, it is important to suddenly stop the fixing roller 301 when the fixing wrapping occurs. As a control method for suddenly stopping the fixing roller 301, for example, there is a short brake described later.

When stopping the fixing roller 301, it is better to separate the heat roller 303 and the pressure roller 302 that come into contact with the fixing roller 301 from the fixing roller 301. This is because when the heat roller 303 and the pressure roller 302 come into contact with the fixing roller 301 whose rotation has stopped, the fixing roller 301 locally becomes hot only at the contacting position and suffers damage.

FIG. 4 is an explanatory diagram of the drive mechanism of the fixing roller 301. This drive mechanism controls the drive of the fixing motor 500 that efficiently drives the fixing roller 301 while recovering the regenerative energy. The drive mechanism includes a motor drive unit 501 and a switch unit 502 whose operation is controlled by the motor control unit 256. The switch unit 502 selectively connects the fixing motor 500 and either the motor drive unit 501 or the power storage unit 503. A voltage conversion unit 504 that converts the output voltage of the power storage unit 503 and supplies it to the load 506 is connected to the power storage unit 503.

The driving force generated by the fixing motor 500 is transmitted to the fixing roller 301 via a gear (not shown). The fixing roller 301 rotates at a rotation speed corresponding to the rotation speed of the fixing motor 500 and the gear ratio. The motor drive unit 501 includes switch elements SW1 to SW4 that form an H-bridge circuit. The fixing motor 500 is rotationally driven by operating the switch elements SW1 to SW4 based on a drive signal which is a control signal output from the motor control unit 256 and flowing a current through the winding of the fixing motor 500. The switch elements SW1 to SW4 are, for example, FETs (Field Effect Transistors) in this embodiment. In the present embodiment, the case where the winding of the fixing motor 500 has one phase will be described, but the configuration of the present embodiment can be applied even to a two-phase and three-phase motor.

The motor drive unit 501 appropriately controls the on and off of the switch elements SW1 to SW4 by the drive signal acquired from the motor control unit 256, and controls the rotation of the fixing motor 500.

The switch unit 502 has three terminals, a fixing motor 500 is connected to the input terminal, a power storage unit 503 is connected to one of the two output terminals, and a motor drive unit 501 is connected to the other. The switch unit 502 may have a switch function of a switching device such as a relay or a transistor. The switch unit 502 is controlled by the motor control unit 256.
The motor control unit 256 controls the switch unit 502 so as to connect the fixing motor 500 and the motor driving unit 501 when the image forming operation is performed (during normal drive control of the fixing motor 500). As a result, the fixing motor 500 is driven by the motor drive unit 501.
On the other hand, the motor control unit 256 controls the switch unit 502 so as to connect the fixing motor 500 and the power storage unit 503 when the fixing motor 500 is stopped or decelerated. As a result, the regenerative current of the fixing motor 500 when the fixing motor 500 is stopped or decelerated is supplied to the power storage unit 503.

The power storage unit 503 is a device having a power storage function such as a capacitor. The voltage conversion unit 504 converts the output voltage of the power storage unit 503 and supplies it to the load 506. The load 506 is, for example, a fan that cools the fuser 109, and can operate by utilizing the energy stored in the power storage unit 503 even when the power supply to the image forming apparatus 1 main body is stopped due to a power failure or the like. With such a configuration, the temperature rise in the image forming apparatus 1 can be suppressed.

Next, the regenerative braking operation and the short braking operation will be described.

During the regenerative braking operation, the switch elements SW1, SW2, SW3, and SW4 of the H-bridge circuit of the motor drive unit 501 are turned off. The fixing motor 500 rotates due to inertia when the drive control is stopped. During the period in which the fixing motor 500 is rotating due to inertia, a counter electromotive force is induced in the winding of the fixing motor 500, and an induced current flows in the winding of the fixing motor 500. In the present embodiment, the induced current is sent to the power storage unit 503 because the fixing motor 500 and the power storage unit 503 are connected by the switch unit 502 during the regenerative braking operation. The power storage unit 503 recovers the induced current as regenerative energy.

The brake torque T1 generated during the regenerative braking operation is the sum of the load torque applied to the fixing motor 500 and the regenerative torque generated by the countercurrent force generated due to the rotation due to the inertia of the fixing motor 500. The regenerative torque changes according to the amount of energy stored in the power storage unit 503. As the amount of energy stored in the power storage unit 503 increases, the amount of regenerative current when the fixing motor 500 is regenerated decreases, so that the regenerative torque decreases. As the amount of energy stored in the power storage unit 503 decreases, the amount of regenerative current when the fixing motor 500 is regenerated increases, so that the regenerative torque increases.

FIG. 5 is an explanatory diagram of the short brake operation. During the short brake operation, one of the switch elements SW1 and SW2 and the switch elements SW3 and SW4 of the H-bridge circuit of the motor drive unit 501 is turned on. That is, the other of the switch elements SW1 and SW2 and the switch elements SW3 and SW4 is in the off state. The winding of the fixing motor 500 is short-circuited by applying the same potential to both ends when any one of the switch elements SW1 and SW2 and the switch elements SW3 and SW4 is turned on. Here, the case where the switch elements SW3 and SW4 are turned on will be described.

When the switch elements SW3 and SW4 are turned on, the fixing motor 500 is short-circuited to the ground. The fixing motor 500 rotates due to inertia when the drive control is stopped. During the period in which the fixing motor 500 is rotating due to inertia, a counter electromotive force is induced in the winding of the fixing motor 500, and as shown by the dotted line in FIG. 5, the fixing motor 500 is fixed via the switch element SW3 and the switch element SW4. An electromotive current flows through the winding of the motor 500. Due to the induced current, torque (short brake torque) in the direction opposite to the rotation direction is generated in the fixing motor 500.

The brake torque T2 generated during the short brake operation is the sum of the load torque and the short brake torque. Unlike the regenerative torque, the short brake torque is not used for recovering the regenerative energy to the power storage unit 503. Therefore, the brake torque T2 generated during the short brake operation is larger than the brake torque T1 generated during the regenerative braking operation. As a result, the braking force generated when the fixing motor 500 is stopped becomes larger during the short braking than during the regenerative braking. Therefore, the short brake can completely stop the fixing motor 500 in a shorter time than the recovery brake.

FIG. 6 is an explanatory diagram of control when the fixing motor 500 is stopped. FIG. 6 shows an operation sequence when the fixing motor 500 is stopped. This operation sequence represents the difference in the stop time of the fixing roller 301 when the fixing motor 500 is stopped between the time when the fixing wrapping is detected and the time when the fixing wrapping is detected.

The stop control in the case other than the case of fixing wrapping detection will be described. In this case, the motor control unit 256 controls the motor drive unit 501 so as to perform the regenerative braking operation at time t1. Further, the motor control unit 256 switches the switch unit 502 to connect the fixing motor 500 and the power storage unit 503. By the time t2 when the rotation of the fixing motor 500 is completely stopped, the regenerative energy of the fixing motor 500 is recovered by the power storage unit 503.

Next, stop control when fixing wrapping is detected will be described. In this case, the motor control unit 256 controls the motor drive unit 501 so as to perform a short brake operation at time t1. The motor drive unit 501 performs a short brake operation until the time t3 when the rotation of the fixing motor 500 is completely stopped.

As described above, when the fixing motor 500 is stopped except when the fixing winding is detected, the fixing motor 500 is braked by the regenerative braking operation, and the regenerative energy is recovered in the power storage unit 503. When the fixing wrapping is detected and the fixing motor 500 is stopped, the fixing motor 500 is suddenly stopped by a short brake operation to suppress the wrapping of the paper P around the fixing roller 301.

When the fixing motor 500 is stopped except when the fixing winding is detected, the fixing roller 301 and the pressurizing roller 302 are separated from each other, so that the fixing motor 500 is completely stopped at time t4 (time t4> time t3). ). Since the regenerative time is long, the regenerative energy can be efficiently recovered in the power storage unit 503.

FIG. 7 is a flowchart showing processing when the fixing motor 500 is stopped.
When the job is started, the system controller 251 starts driving the fixing motor 500 in the fixing device 109 by the motor control unit 256 (S1). During the execution of the job, the system controller 251 monitors an abnormality such as a jam or an operation error in the image forming apparatus 1 based on the detection result of the sensors 258 and the control signal to each unit (S2).

If the occurrence of an abnormality is not detected (S2: N), the system controller 251 continues to monitor the occurrence of the abnormality until the job is completed (S5: N). When the job ends without detecting the occurrence of an abnormality (S2: N, S5: Y), the system controller 251 connects the fixing motor 500 and the power storage unit 503 by the switch unit 502 (S6). As a result, the system controller 251 stops the fixing motor 500 while being regenerated by the regenerative brake (S7), and ends the job.

When the occurrence of an abnormality is detected (S2: Y), the system controller 251 determines whether or not the abnormality is caused by fixing wrapping from the difference in detection timing between the inlet sensor 401 and the outlet sensor 402 (S3). When the abnormality is caused by the fixing wrapping (S3: Y), the system controller 251 stops the fixing motor 500 by the short brake (S4), and ends the job. When the abnormality is not caused by the fixing wrapping (S3: N), the system controller 251 stops the fixing motor 500 by the regenerative brake (S6, S7), and ends the job.

As described above, the image forming apparatus 1 of the present embodiment includes the fixing device 109 having a configuration for storing the regenerative energy in the power storage unit 503, and when the fixing motor 500 is stopped except for the fixing winding, the fixing motor 500 is regenerated. Stop with the brake. When the fixing motor 500 is stopped by the fixing winding, the fixing motor 500 is stopped by the short brake. As a result, the image forming apparatus 1 can quickly stop the fixing motor 500 when the fixing wrapping occurs while recovering the regenerative energy generated when the fixing motor 500 is decelerated or stopped. Therefore, it is possible to reduce the energy loss that occurs when the fixing motor 500 is decelerated or stopped, and to prevent the fixing device 109 from being damaged by the fixing winding or the like.

In the above example, the configuration in which the fixing motor 500 is stopped by the short brake when the fixing winding occurs is described. In addition to this, the fixing motor 500 may be stopped by the short brake when a jam occurs in the vicinity of the fixing device 109 or when an abnormality occurs due to the fixing device 109 such as an excessive temperature rise of the fixing device 109. In this case, the system controller 251 determines the overheating of the fuser 109 based on the temperature detected by the thermistor 253.

The operation of quickly stopping the fixing motor 500 may be a reverse brake as well as a short brake. The reverse braking is performed by controlling the current of the winding of the fixing motor 500 so that the reverse rotation torque is generated. In this case, the motor control unit 256 controls the switch elements SW1 to SW4 of the motor drive unit 501 on and off so that the fixing motor 500 generates the reverse rotation torque.

In the present embodiment, an example in which the energy stored in the power storage unit 503 is used for the operation of the fan has been described. In addition to this, the energy stored in the power storage unit 503 may be used for other purposes such as the operation of the CPU 270 in the energy saving mode.

Claims (10)

An image forming means for forming an image on an image carrier,
A transfer means for transferring an image from the image carrier to paper,
A fixing means having a first roller and a second roller and fixing the image on the paper by sandwiching and transporting the paper on which the image is transferred between the first roller and the second roller.
A motor that rotationally drives the first roller and
The driving means for driving the motor and
A control means that controls the drive means to control the drive of the motor, and
Equipped with storage means
The control means stops the motor while recovering the regenerative energy from the motor and storing it in the power storage means when an abnormality not caused by the fixing means occurs, and the regenerating means occurs when an abnormality caused by the fixing means occurs. The motor is stopped in a shorter time than when energy is recovered and stopped.
Image forming device. When an abnormality not caused by the fixing means occurs, the control means ends the driving of the motor by the driving means, and the regenerative energy generated by the rotation of the motor after the driving due to inertia is stored in the storage means. The motor is stopped while being stored in the motor.
The image forming apparatus according to claim 1. The control means is characterized in that the first roller and the second roller are separated from each other when an abnormality not caused by the fixing means occurs.
The image forming apparatus according to claim 1 or 2. The control means is characterized in that, when an abnormality caused by the fixing means occurs, the drive means short-circuits the motor to stop the motor.
The image forming apparatus according to any one of claims 1 to 3. The control means is characterized in that the motor is short-circuited by applying the same potential to both ends of the winding of the motor by the drive means.
The image forming apparatus according to claim 4. The control means is characterized in that, when an abnormality caused by the fixing means occurs, the driving means generates a reverse rotation torque in the motor to stop the motor.
The image forming apparatus according to any one of claims 1 to 3. Further comprising a selection means for selectively connecting the motor, the drive means, or any one of the power storage means.
The control means connects the motor and the power storage means to the selection means when an abnormality not caused by the fixing means occurs, and when an abnormality caused by the fixing means occurs, the motor and the motor are connected to the selection means. It is characterized by connecting with a driving means,
The image forming apparatus according to any one of claims 1 to 6. The fixing means includes a first detecting means for detecting the entry of the paper into the fixing means and a second detecting means for detecting that the paper has passed through the fixing means.
The control means is characterized in that it determines the occurrence of an abnormality caused by the fixing means based on the difference in detection timing between the first detection means and the second detection means.
The image forming apparatus according to any one of claims 1 to 7. The control means causes an abnormality caused by the fixing means when the second detecting means does not detect the passage of the paper even after a predetermined time has elapsed after detecting the entry of the paper by the first detecting means. Is characterized by determining that
The image forming apparatus according to claim 8. The fixing means has a measuring means for detecting the internal temperature, and has a measuring means.
The control means is characterized in that it determines the occurrence of an abnormality caused by the fixing means based on the temperature detected by the measuring means.
The image forming apparatus according to any one of claims 1 to 7.

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