JP2003208060A - Image forming apparatus and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus carrying out detection of the existence of a unit without providing loading detection sensor for the attaching and detaching unit, as the image forming apparatus carrying out image formation using the attaching and detaching unit such as a developing unit, a carrying belt unit and a fixing device unit. <P>SOLUTION: The load on a motor driving the attaching and detaching unit is detected and the existence of the attaching and the detaching unit can be detected by the size of the load. For example, the existence of the attaching and detaching unit is detected (S29, S210) by detecting the rotating number of the motor during a specified period (S27) and then comparing with a standard rotating number which is determined beforehand (S28). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and a control method thereof, and more particularly to an image forming apparatus which forms an image using a detachable unit and a control method thereof.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus often uses a detachable unit (attachable / detachable unit) in which consumable items are enclosed for the purpose of facilitating maintenance. First, a configuration of a color image forming apparatus using an electrophotographic method will be described as an example of a conventional image forming apparatus using such a detachable unit.

FIG. 11 is a diagram showing a main configuration of a color image forming apparatus having image forming portions for four colors, that is, yellow Y, magenta M, cyan C and black K. In the figure, 1Y, 1M, 1C and 1K are developing units for yellow, magenta, cyan and black, respectively, and are photosensitive drums 1aY, 1aM, 1aC and 1a for forming electrostatic latent images.
K, a developing device (not shown) for developing the electrostatic latent image, and storage units 1bY, 1bM, 1bC, 1 for storing predetermined information.
The bK has a unitized structure and is attachable to and detachable from the image forming apparatus main body. In the following description, the developing units 1Y, 1M, 1C for Y, M, C and K will be described.
1K may be collectively referred to as developing unit 1. The same notation may be applied to other elements provided for each color such as the photosensitive drum and the storage unit.

The storage unit 1b transmits / receives predetermined information to / from a communication unit (not shown) on the main body side. 6Y, 6M, 6C, 6K
Is a motor for driving each developing unit.

2Y, 2M, 2C, and 2K are photosensitive drums 1aY, 1aM, and 1a corresponding to image signals, respectively.
A laser scanner 3 that exposes C and 1aK to form an electrostatic latent image on a photosensitive drum is an endless conveyor belt that sequentially conveys a recording medium such as paper to the developing unit 1 of each color,
It is unitized together with a storage unit 3a that stores predetermined information and a drive roller 4 described later, and is configured to be attachable to and detachable from the main body.

Reference numeral 4 denotes a drive roller which is connected to a motor 6e through a gear or the like and drives the conveyor belt 3, 6e denotes a motor which drives the drive roller 4, and 5 denotes a recording material (toner or the like) transferred to a recording medium. Is a fixing device that melts and fixes the toner, and is unitized with the storage unit 5a that stores predetermined information.
It has a structure that can be attached to and detached from the main body. 6f is a motor for driving the fixing unit.

Photosensitive drum 1a, conveyor belt 3, fixing device 5
Are consumable items that deteriorate with the use of the image forming apparatus and need to be replaced when they reach the end of their lives. Therefore, the developing unit 1 in which the photosensitive drum 1a and the developing device are unitized, the belt unit in which the conveying belt 3 is unitized, so that the user can easily replace the photosensitive drum 1a and the developing unit,
Like the fixing unit that unitizes the fixing device 5,
The unit is detachable from the image forming apparatus main body.

The use of the replaceable unit has advantages such as easy maintenance, but on the other hand, the influence of the individual difference of the unit on the image becomes a problem. for that reason,
As described above, the storage units 1b, 3a and 5 are provided in each unit.
By providing a, information such as characteristics peculiar to the unit is stored, and when the image is formed, the main body side reads the information and performs image formation control suitable for the characteristics of the unit to obtain a stable image. There is a known technique for enabling the above.

Next, the operation of the image forming apparatus will be described. When data to be image-formed is sent from an external device such as a personal computer (PC) to the image-forming device, an image signal for each color is generated by a predetermined process such as bitmap expansion of the data. When an image can be formed, a sheet serving as a recording medium is conveyed from a sheet cassette (not shown), reaches the conveyor belt 3, and the conveyor belt 3 sequentially conveys the sheet to the developing units 1 for the respective colors. The image signal of each color is sent to each laser scanner 2 in synchronism with the sheet conveyance by the conveyor belt 3,
An electrostatic latent image is formed on the photosensitive drum 1a. The electrostatic latent image is developed by a developing device (not shown) in each developing unit, and a toner image is formed on the photosensitive drum. The toner image is sequentially transferred onto the paper by a transfer unit (not shown). In the figure, images, development, and transfer are sequentially performed in the order of Y, M, C, and K. After that, the paper is separated from the conveyor belt 3, the toner image is thermally fixed on the paper by the fixing device 5, and the paper is discharged to the outside. Note that various parameters used for image formation are stored in the storage units 1b, 3a, and 5a provided in each of the developing unit 1, the conveyor belt unit, and the fixing unit.
Optimal values are set for the characteristics of each unit based on the values read from.

In such an image forming apparatus, a DC brushless motor is used as a motor (6e, 6f, etc.) for driving the replaceable unit. FIG. 12 shows a configuration example of the DC brushless motor and its drive circuit. The DC brushless motor 50 has a coil 51 and a rotor 52 that are U-, V-, and W-three-phase star-connected. Furthermore, three Hall elements 53 that detect the magnetic poles of the rotor are provided as a rotor position detection unit, and the output thereof is amplified by an amplifier 54. Further, it has a rotation speed detection unit composed of a magnetic pattern 55 and a magnetic sensor 56 provided on the outer circumference of the rotor, the output of which is amplified by an amplifier 57 and input to the speed control unit 60.

Reference numeral 70 denotes a driver for driving a DC brushless motor, which includes three high-side transistors 71 and three low-side transistors 72, and U of the coil 51,
It is connected to V and W. Reference numeral 58 is an energization logic circuit that controls energization. 80 is a current limiter unit.

The energization logic circuit 58 includes a Hall element 53.
The position of the rotor is specified by the rotor position signals HU to HW that are generated, and a phase switching signal is generated. The phase switching signals UU to UW and LU to LW control the on / off states of the transistors 71 and 72 of the driver 70 to sequentially switch the phases to be excited and rotate the rotor 52.

The speed controller generates a voltage proportional to the motor rotation speed with the F / V converter 61, and then the comparator 62.
Then, it is compared with the reference voltage Vref to obtain its differential output. Further, the PLL section 63 compares the phases of the motor rotation frequency signal and the reference frequency signal Fref to obtain an output according to the phase shift. Further, the two outputs are mixed by the mixer 64, and the PWM signal generator 65 generates the PWM signal. P
The WM signal is input to the energization logic circuit 58 to control the rotation speed of the motor.

The current limiter 80 has a detection resistor 81,
The drive current is converted into a voltage, and the comparator 82 outputs the reference voltage Vre.
Compare with f. As a result of the comparison, when the voltage conversion value of the drive current is larger than the reference voltage, a signal is output to the energization logic circuit 58 so as to stop the drive.

[0015]

In such a conventional image forming apparatus, whether or not a unit detachable from the main body, for example, a developing unit, a conveyor belt unit, a fixing unit, etc. is mounted is stored in the unit. Judgment is based on whether communication with the department is possible. That is, if the communication can be performed normally, it is determined that the device is attached, and if the communication cannot be performed, it is determined that the device is not attached.

Therefore, if the storage unit provided in the unit is out of order, for example, if the communication with the storage unit cannot be performed normally, it is determined that there is no unit, and the unit itself can be used. Image forming processing cannot be performed. As described above, even though the image forming apparatus is not fatal, the image cannot be formed, resulting in deterioration of usability. Alternatively, due to a failure of the communication unit,
It may be judged that abnormal data can be received even though communication is not possible. In this case, in reality, the unit is erroneously detected even though the unit is not attached. Furthermore, there is a risk that parameters for image formation will be set based on abnormal data, leading to failure of the image forming apparatus body.

In order to prevent such a situation, a detection sensor such as a photo sensor is generally used together. However, for example, in a color printer having a developing unit for four colors, a total of six detection sensors are required for the developing unit, one for the belt unit and one for the fixing unit. It is necessary to input the sensor output to the CPU or the like in order to determine the presence or absence of.
Therefore, six input ports for the CPU and the like are required, and in a color printer that originally requires a large number of ports, the number of ports may be insufficient, and the specifications of the CPU may have to be increased. As a result, the cost and power consumption of the image forming apparatus are increased.

However, even if the detection sensors are used together, if each unit presence / absence detection sensor fails, it may be determined that there is no unit even though the unit is attached, and image formation may not be possible. There is no change.

[0019]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and its object is to:
In an image forming apparatus that forms an image by using a detachable unit such as a developing unit, a conveyor belt unit, and a fixing unit, an image forming apparatus capable of detecting the presence or absence of the detachable unit without providing a mounting detection sensor and its control To provide a method.

That is, the gist of the present invention is, in an image forming apparatus for forming an image using the detachable unit, a motor for driving the attached detachable unit, a load detection means for detecting the load of the motor, and a detection. The image forming apparatus has an presence / absence detecting unit that detects whether the detachable unit is mounted or not mounted based on the applied load.

Another aspect of the present invention is a control method of an image forming apparatus having a motor for driving a detachable unit and performing image formation by using the detachable unit, the load of the motor being detected. A control method for an image forming apparatus, comprising: a load detection step; and a presence / absence detection step of detecting attachment / detachment of a detachable unit based on the detected load.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on its preferred embodiments with reference to the drawings. In the following embodiments, a case where a color laser beam printer having the configuration described with reference to FIG. 11 is used as an image forming apparatus and the presence / absence of the developing unit 1 (Y, M, C, K) is detected. Although described as an example, the present invention can be applied to a color / monochromatic image forming apparatus having another configuration, and can also be applied to the presence / absence detection of another unit such as a conveyor belt unit or a fixing unit. Is.

FIG. 3 is a block diagram showing a main configuration of the image forming apparatus according to the present embodiment, showing a state in which the image forming apparatus is connected to a host computer 18 as an external device.

In the figure, 10 is a printer. 11
Is a printer control unit that controls each device in the printer, and includes, for example, a CPU, a RAM, a ROM, and the like.
Reference numeral 12 is a power supply for supplying electric power to each device in the printer. Reference numeral 13 denotes sensors that detect the status of each part in the printer. A motor control unit 14 controls the motors according to an instruction from the printer control unit 11. Reference numeral 15 is a motor that is a power source of each device in the printer. A display unit 16 notifies the user of the operating status of the printer. A communication controller 17 communicates between the printer and the host computer 18. A host computer 18 transfers data to be printed by the printer 10. A communication unit 19 communicates with the developing unit.

Next, the configuration of the motor control unit 14 and its surroundings, which is a characteristic configuration of the present invention, will be described with reference to FIGS. 4, 5 and 6. 4 is a block diagram showing the motor control unit 14 according to the present embodiment, the motor 40 controlled by the motor control unit 14 and its peripheral circuits, and FIG.
FIG. 3 is a circuit diagram showing in more detail.

Reference numeral 20 is a DSP, 40 is a DC brushless motor, 30 is a driver for controlling electric power to the motor, and 46 is a rotating body (for example, a photosensitive drum in the case of a developing unit) driven by the motor. DSP (Digit
al Signal Processor) 20 is a DC brushless motor 40
Based on the phase switching control based on the rotor position signal from the printer controller, the start / stop control of the motor 40 based on the control signal from the printer controller 11, and the comparison between the speed signal from the printer controller 11 and the output of the speed detector. Driver 3
The speed of the motor 40 is controlled via 1.

The DC brushless motor 40 has a U-, V-, and W 3-phase star-connected coil 43 and a rotor 44 (FIG. 5). Further, three Hall elements 42 for detecting the magnetic poles of the rotor 44 are provided as a position detecting portion of the rotor 44, and the outputs thereof are connected to the DSP 20. Also, the rotor 4
4 has a rotation speed detection unit composed of a magnetic pattern 45 and a magnetic sensor 41 provided on the outer periphery of the output 4, and its output is DS.
It is connected to P20.

Reference numeral 30 is a driver for driving the DC brushless motor 40, which includes three high-side transistors 31 and three low-side transistors 32, which are connected to U, V, and W of the coil 43, respectively. 34 is a current detection resistor,
Converts motor drive current to voltage. The generated voltage is DS
It is taken into the A / D port of P20.

The DSP 20 specifies the position of the rotor 44 based on the rotor position signals HU to HW generated by the Hall element 42 and generates a phase switching signal. Phase switching signal UU
.About.UW and LU to LW sequentially turn on and off the respective transistors of the driver to sequentially switch the exciting phases to rotate the rotor.

Further, the DSP 20 compares the rotation speed target value with the rotation speed information, and generates and outputs a PWM signal. PW
The value 0 of the M signal is duty0, and the value 255 is duty100.
Becomes The PWM signal is ANDed with the phase switching signals UU to UW by the NAND gate 33 to chop the drive current to control the rotation speed of the motor. It should be noted that all processing may be performed by the DSP 20 without using the NAND gate 33.

The configuration other than the motor control circuit 14 in FIGS. 4 and 5 can be applied to other unit driving motors 6e and 6f (see FIG. 11) used in the image forming apparatus.

FIG. 6 is a block diagram showing a configuration example of the DSP 20. 21 is a program controller, 22a is an ALU that performs addition / subtraction and logical operations, 22b is a MAC that performs product-sum operations, 23 is a data memory, 24 is a program memory, 25a is a data memory bus, 25b is a program memory bus, and 26 is A / D port, 27 is a serial port, 28 is a timer, and 29 is an I / O port. In this way, the memory is made independent for the data and the program, the bus is also separated into the data bus and the program bus, and the MAC for executing the multiplication and the addition in one machine cycle enables the high-speed operation.

Next, the operation of the image forming apparatus according to this embodiment will be described. FIG. 1 is a flowchart showing a processing procedure when the image forming processing according to the present embodiment sets the image forming control parameter. This parameter setting process can be performed at any timing, but it is preferably performed when the image forming apparatus is powered on or when the door for accessing the inside of the image forming apparatus is closed.

The printer control section 11 is a detachable unit (developing unit in this embodiment) via the communication section 19.
It communicates with the storage unit 1b included in the device (step S1) and determines whether communication can be normally performed (step S2). If the communication can be normally performed, the parameters used at the time of image formation are set in, for example, a RAM (not shown) or a non-volatile RAM in the printer control unit 11 based on the predetermined information read from the storage unit 1b (step S3).

On the other hand, if the communication cannot be performed normally, the motor control unit 14 is instructed to execute the detachable unit presence / absence detection process (step S4). It waits until the result of the presence / absence detection is notified from the motor control unit 14 (step S5), and determines whether or not there is a detachable unit (step S6). When the result that there is no detachable unit is received, for example, the display unit 16
The user is informed of the absence of the unit by displaying a message such as "no detachable unit" on the display panel constituting the unit or by issuing a warning sound from a speaker (not shown) (step S7).

If there is a detachable unit in step S6, the printer controller 11 sets a predetermined value that is stored in advance in a non-volatile storage means such as a ROM (not shown) as a parameter used during image formation (step S6).
8). As the parameter value prepared in advance in the printer control unit 11, for example, a value determined under arbitrary conditions such as a center value of a range that can be set for each parameter or an average value of setting values used in the past. Can be used.

Next, the attachment / detachment unit presence / absence detection processing executed by the motor controller 14 corresponding to step S4 of FIG. 1 will be described with reference to the flowchart shown in FIG. In the present embodiment, the motor control unit 14 determines the presence or absence of the detachable unit based on the magnitude of the load torque of the motor that drives the detachable unit. The magnitude of the load torque is
By the open loop control, the motor can be driven with a constant input power, and it can be detected from the motor rotation speed at that time.

The motor controller 14 is the printer controller 11
When the execution of the detachable unit presence / absence detection is instructed by the CPU, the PWM value is set so that the motor is driven with a constant input power (step S22). For example, the PWM value is fixed to 100.

Next, the timer 28 is set to a predetermined time (step S23). This timer value is set to a time sufficient for the motor speed to reach the equilibrium state. further,
The driving of the motor is started by the PWM value (step S24), and the timer 28 is started. Then, when the time-out occurs (step S26), the motor rotation speed is measured (step S27).

After the measurement, the detected motor rotation speed is compared with the reference rotation speed (step S28) to determine the presence or absence of the detachable unit. If the detected rotation speed is higher than the reference rotation speed, the load torque is small, and it is determined that there is no detachable unit (step S29). If the detected rotation speed is equal to or lower than the reference rotation speed, the load torque becomes large, and it is determined that the detachable unit is present (step S210). After the presence / absence of the detachable unit presence / absence is determined, the detachable unit presence / absence detection result is notified to the printer control unit (step S211), and the detection process is terminated.

Although the presence / absence of the developing unit is determined in the present embodiment, the motor control unit 14 determines that the other units are
Needless to say, the presence / absence of these units can be determined by performing the same processing on the drive motors such as the conveyor belt unit and the fixing unit.

(2nd Embodiment) In the first embodiment of the present invention, the presence or absence of the detachable unit is determined by detecting the load torque from the rotation speed of the motor for a predetermined time. On the other hand, the present embodiment is characterized in that the motor is controlled in a closed loop, and the load torque of the motor is detected by the magnitude of the supplied electric power when the motor is driven at a constant rotation speed. Therefore, the other parts of the configuration, the parameter setting process of the printer control unit 11 and the like are the same as those in the first embodiment, and the description thereof will be omitted.

Next, the detachable unit presence / absence detection processing of the printer controller 14 in this embodiment will be described with reference to the flowchart shown in FIG. Printer control unit 11
When instructed to execute the detachable unit presence / absence detection by the motor control unit 14, the motor control unit 14 sets a final target rotation speed set in advance. (Step S72)

Next, after the motor driving is started by the closed loop control (step S73), the motor rotation speed is detected (step S74), and the motor is controlled to rotate at the final target rotation speed.

When the motor rotation speed reaches the final target rotation speed (step S75), the timer 28 is set and activated, and the PWM value addition variable α is cleared to zero.
(Step S76). After that, at regular intervals, PWM
The PWM value is added to the value addition variable α (step S7
7) When the timer 28 times out, the addition of the PWM value is finished. (Step S79).

After the addition of the PWM values is completed, the value of the variable α representing the sum of the calculated PWM values is compared with a predetermined reference value (step S710) to determine the presence / absence of the detachable unit. If the total sum α of the calculated PWM values is larger than the reference value, the load torque becomes large, and it is determined that the detachable unit is present (step S711). If the sum α of the calculated PWM values is less than or equal to the reference value, the load torque is small, and it is determined that there is no detachable unit (step S712). After the presence / absence of the detachable unit presence / absence determination, the printer controller 11 is notified of the detachable unit presence / absence detection result (step S713), and the detection process ends.

Although the presence / absence of the developing unit is determined in the present embodiment, the motor control unit 14 determines whether another unit is
Needless to say, the presence / absence of these units can be determined by performing the same processing on the drive motors such as the conveyor belt unit and the fixing unit. Further, in the present embodiment, the applied power is detected from the PWM value, but the drive current value converted into the voltage is A of the DSP 20.
The input power may be detected using the value captured by the / D port.

(3rd Embodiment) In the second embodiment of the present invention, the load torque of the motor is controlled by the magnitude of the applied power when the motor is controlled in a closed loop and driven at a constant rotation speed. It was detected and the presence or absence of the detachable unit was determined. On the other hand, the present embodiment is characterized in that the load torque is detected and the presence or absence of the detachable unit is determined from the magnitude of the input power when the motor is accelerated from a certain speed to a certain speed. Therefore, the other parts of the configuration, the parameter setting process of the printer control unit 11 and the like are the same as those in the first embodiment, and the description thereof will be omitted.

Next, the detachable unit presence / absence detection processing of the printer controller 14 in this embodiment will be described with reference to the flowchart shown in FIG. When the printer controller instructs to execute the detachable unit presence / absence detection, the motor controller 14 sets a predetermined final target rotation speed,
The PWM value addition variable α is cleared to 0 (step S8).
2).

Next, the motor drive is started (step S8).
3), the motor is accelerated from the rotation speed = 0 rpm to the final target rotation speed. Then, during motor acceleration, PWM is performed at a constant cycle.
The value is detected and the PWM value is added (step S8
4).

The number of rotations of the motor is detected (step S8
5) It is determined whether or not the final target rotation speed has been reached (step S86). When the final target rotation speed is reached, the motor drive and PWM value detection and addition processing are stopped, and the calculated P
The value of the variable α representing the sum of the WM values is compared with a predetermined reference value (step S87) to determine the presence / absence of a detachable unit. If the total sum α of the calculated PWM values is larger than the reference value, the load torque becomes large, and it is determined that the detachable unit is present (step S88). Sum of calculated PWM values α
Is smaller than the reference value, the load torque is small and it is determined that there is no detachable unit (step S89). After the presence / absence of the detachable unit presence / absence determination, the printer controller 11 is notified of the detachable unit presence / absence detection result (step S810), and the detachable unit presence / absence detection process ends.

Although the presence / absence of the developing unit is determined in the present embodiment, the motor control unit 14 determines that the other units are
Needless to say, the presence / absence of these units can be determined by performing the same processing on the drive motors such as the conveyor belt unit and the fixing unit. Further, in the present embodiment, the applied power is detected from the PWM value, but the drive current value converted into the voltage is A of the DSP 20.
The input power may be detected using the value captured by the / D port.

(Fourth Embodiment) In the present embodiment, in the detachable unit detection process,
When the electric power supplied to the motor is changed from 0 to a predetermined value, the load torque is detected from the time required for the rotation speed of the motor to reach a predetermined value from 0 rpm, and the presence or absence of the detachable unit is determined. Characterize. Therefore, the other parts of the configuration, the parameter setting process of the printer control unit 11 and the like are the same as those in the first embodiment, and the description thereof will be omitted.

Next, the detachable unit presence / absence detection processing of the printer controller 14 in this embodiment will be described with reference to the flowchart shown in FIG. Printer control unit 11
When instructed to execute the detachable unit presence / absence detection from the motor control unit 14, the motor control unit 14 sets the PWM value, the reference rotation speed of the motor, and the timer 28, and activates the timer 28 (step S92). The reference rotation speed of the motor is set to a value smaller than the motor rotation speed reached when the motor is driven with the set PWM value while the maximum load is being applied to the motor. Further, driving of the motor is started (step S93), and the motor speed is detected continuously or at regular intervals (step S95).

It is determined whether or not the motor speed reaches the target rotation speed (step S96), and when the target rotation speed is reached, the value of the timer 28 at that time is stored (step S9).
7). After the storage is completed, the stored timer value is compared with the reference value (step S98) to determine the presence / absence of the detachable unit.
If the stored timer value is less than or equal to the reference value, the load torque is small and it is determined that there is no detachable unit (step S9).
9). If the stored counter value is larger than the reference value,
The load torque becomes large, and it is determined that the detachable unit is present (step S910).

After the presence / absence of the detachable unit presence / absence is determined, the printer controller is notified of the detachable unit presence / absence detection result (step S
911), the attach / detach unit presence / absence detection process ends. In the present embodiment, the presence / absence of the developing unit is determined, but the motor control unit 14 performs the same processing on the drive motors of other units, such as the conveyor belt unit and the fixing unit, so that these units can be processed. It goes without saying that the presence / absence determination can be performed.

(Fifth Embodiment) In the present embodiment, in the detachable unit detection process,
When the input power to the motor driven at a constant rotation speed is changed to 0, the load torque is detected from the time required until the motor rotation speed falls below a certain value, and the presence or absence of the detachable unit is determined. It is characterized by doing. Therefore, the other parts of the configuration, the parameter setting process of the printer control unit 11 and the like are the same as those in the first embodiment, and the description thereof will be omitted.

Next, the detachable unit presence / absence detection processing of the printer controller 14 in this embodiment will be described with reference to the flowchart shown in FIG. Printer control unit 1
When the instruction to execute the detachable unit presence / absence detection is instructed from 1, the motor control unit 14 sets a predetermined motor rotation speed (step S102) and accelerates the motor by closed loop control (step S103). The number of rotations of the motor is detected (step S104), and it is determined whether or not the set number of rotations has been reached (step S105). When the set rotation speed is reached, the timer 28 is reset and started (step S106). Further, the PWM value is set to 0 (step S107), and the power supply to the motor is stopped.

The motor speed is detected (step S10
9), it is determined whether or not the motor rotation speed is below a predetermined reference rotation speed (step S1010). When the rotation speed of the motor falls below the reference rotation speed, the value of the timer 28 is stored (step S1011), the reference values are compared (step S1012), and the presence or absence of the detachable unit is determined. If the stored timer value is larger than the reference value, the load torque is small and it is determined that there is no detachable unit (step S101).
2). If the stored counter value is less than or equal to the reference value, the load torque is high, and it is determined that the detachable unit is present (step S1013). After the determination of the presence / absence of the detachable unit, the printer control unit 11 is notified of the detachment unit presence / absence detection result (step S1014), and the detachment unit presence / absence detection process ends.

Although the presence / absence of the developing unit is determined in the present embodiment, the motor control unit 14 determines that the other unit
Needless to say, the presence / absence of these units can be determined by performing the same processing on the drive motors such as the conveyor belt unit and the fixing unit.

[0061]

Other Embodiments In the above embodiments, only the case where the present invention is applied to a laser beam printer as an example of an image forming apparatus has been described. However, the essence of the present invention is to detect the presence / absence of a detachable unit used in an image forming apparatus by using a motor that drives the detachable unit. It is obvious that the present invention can be applied to other printers such as a liquid crystal printer, and any device having an image forming function, such as a copying machine, a facsimile machine, and a multifunction machine.

It should be noted that the software program for realizing the functions of the above-described embodiment (in the embodiment, the program corresponding to the flowchart shown in any one or more of FIGS. 1, 2, and 7 to 10) and itself. A computer-readable storage medium storing the above-mentioned data also constitutes the present invention.

In this case, the program may take any form such as an object code, a program executed by an interpreter, or script data supplied to an OS as long as it has the function of the program.

As a recording medium for supplying the program, for example, a floppy disk, a hard disk,
Magnetic recording media such as magnetic tape, MO, CD-ROM, C
D-R, CD-RW, DVD-ROM, DVD-R, D
There are optical / magneto-optical storage media such as VD-RW and nonvolatile semiconductor memory.

[0065]

As described above, according to the present invention,
In an image forming apparatus that forms an image using a detachable unit such as a developing unit, a conveyor belt unit, and a fixing unit, it is possible to detect the presence or absence of the detachable unit attachment detection sensor, which increases the cost and waste of the apparatus. Power consumption and deterioration of usability can be suppressed.

[Brief description of drawings]

FIG. 1 is a flowchart showing an image forming control parameter setting process in an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a detachable unit presence / absence detection process in FIG.

FIG. 3 is a block diagram showing a main configuration of the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a motor control unit and its peripheral circuits in FIG.

5 is a circuit diagram showing the motor control unit, driver, and motor portion in FIG. 4 in more detail.

6 is a block diagram showing a configuration example of a DSP in FIG.

FIG. 7 is a flowchart showing a detachable unit presence / absence detection process in the image forming apparatus according to the second embodiment of the present invention.

FIG. 8 is a flowchart showing a detachable unit presence / absence detection process in the image forming apparatus according to the third embodiment of the present invention.

FIG. 9 is a flowchart showing a detachable unit presence / absence detection process in the image forming apparatus according to the fourth embodiment of the present invention.

FIG. 10 is a flowchart showing a detachable unit presence / absence detection process in the image forming apparatus according to the fifth embodiment of the present invention.

FIG. 11 is a diagram showing a main configuration of a color laser printer as an example of an image forming apparatus to which the present invention can be applied.

FIG. 12 is a diagram showing a circuit configuration related to a conventional DC brushless motor and its drive control.

[Explanation of symbols]

1 ... Photosensitive drum 2 ... Laser scanner 3 ··· Conveyor belt 4 ... Drive roller 5 ... Fixer 6 ... Motor 10 ... Printer 11 ... Printer control unit 12 ... Power supply 13 ... Sensors 14 ... Motor control unit 15 ... Motors 16 ... Display section 17 ... Communication controller 18 ... Host computer 19 ... Communication section 20 ... DSP 21 ... Program controller 22a ... ALU 22b ... ・ MAC 23 ... Data memory 24 ... Program memory 25a ... Data memory bus 25b ... Program memory bus 26 ... A / D port 27 ... Serial port 28 ... Timer 29 ... I / O port 30 ... driver 31 ... High side transistor 32 ... Low side transistor 33 ... Nand Gate 34 ... Current detection resistor 40 ... DC brushless motor 41 ... Magnetic sensor 42 ... Hall element 43 ... Coil 44 ... Rotor 45 ... Magnetic pattern 46 ... Rotating body 50 ... DC brushless motor 51 ... Coil 52 ... Rotor 53 ... Hall element 54 ... Amplifier 55 ... Magnetic pattern 56 ... Magnetic sensor 57 ... Amplifier 58 ... Energizing logic circuit 60 ··· Speed control unit 61 ... F / V converter 62 ... Comparator 63 ... PLL 64 ··· Mixer 65 ... PWM signal generator 70 ... Driver 71 ... High side transistor 72 ... Low side transistor 80 ・ ・ ・ ・ Current limiter 81 ... Current detection resistor 82 ... Comparator

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2C061 AQ06 AR01 BB12 CF03 CF06                       CF08 HH11 HJ02 HK08 HK11                 2H027 DA01 DA27 DA35 DA50 DE07                       EC06 EE08 EE10 GB07 HA12                       HB13 HB14 HB16                 2H071 BA03 BA13 BA17 BA20 BA34                       DA12 DA15 DA23 DA32 EA18

Claims (20)

[Claims] 1. An image forming apparatus for forming an image using a detachable unit, a motor for driving the attached detachable unit, load detecting means for detecting a load of the motor, and the detected load. Based on the mounting of the detachable unit,
An image forming apparatus, comprising: presence / absence detection means for detecting non-attachment. 2. The image according to claim 1, wherein the load detection means detects the load of the motor based on the number of rotations for a predetermined time when the motor is driven with a constant input power. Forming equipment. 3. The image forming apparatus according to claim 1, wherein the load detection unit detects the load of the motor based on the amount of input electric power when the motor is driven at a constant rotation speed. . 4. The load detection means detects the load of the motor based on the amount of input power required to increase the rotation speed of the motor by a predetermined number. Image forming apparatus. 5. The load detection means detects the load of the motor based on the time required for the rotation speed of the motor to change by a predetermined amount when the input power to the motor is changed. The image forming apparatus according to claim 1, wherein: 6. The apparatus further comprises: a communication unit for communicating with the detachable unit; and an image forming condition setting unit for setting an image forming condition based on information read from the detachable unit by the communication unit. The image forming apparatus according to any one of claims 1 to 5. 7. The image according to claim 6, wherein the attachment / detachment of the attachment / detachment unit is detected by using the load detection unit and the presence / absence detection unit according to a result of communication by the communication unit. Forming equipment. 8. When the communication by the communication unit is not normally terminated, the load detection unit and the presence / absence detection unit are used to detect the attachment / detachment of the detachable unit, and the attachment of the detachable unit is detected. 8. The image forming apparatus according to claim 7, wherein the image forming condition setting means sets the image forming condition stored in advance in the case of the above. 9. The image forming apparatus according to claim 1, wherein the detachable unit incorporates a consumable item used for the image formation. 10. The image forming apparatus according to claim 9, wherein the consumable item includes at least one of a recording material, a photoconductor, a conveyance belt for a recording medium, and a fixing device. 11. A method for controlling an image forming apparatus having a motor for driving a detachable unit, wherein the detachable unit is used to form an image, the load detecting step comprising: detecting a load of the motor; Mounting the detachable unit based on the detected load,
A presence / absence detecting step of detecting non-attachment. 12. The image according to claim 11, wherein the load detecting step detects the load of the motor based on the number of rotations for a predetermined time when the motor is driven with a constant input power. Control method of forming apparatus. 13. The image forming apparatus according to claim 11, wherein the load detection step detects the load of the motor based on the amount of electric power supplied when the motor is driven at a constant rotation speed. Control method. 14. The load detection step according to claim 11, wherein the load detection step detects the load of the motor based on a magnitude of input electric power required to increase the rotation speed of the motor by a predetermined number. A method for controlling an image forming apparatus. 15. The load detection step detects the load of the motor based on the time required for the rotation speed of the motor to change by a predetermined amount when the input power to the motor is changed. The method of controlling an image forming apparatus according to claim 11, further comprising: 16. The method further comprises a communication step of communicating with the removable unit, and an image forming condition setting step of setting an image forming condition based on information read from the removable unit in the communication step. Item 11
A method for controlling the image forming apparatus according to claim 15. 17. The image according to claim 16, wherein the attachment / detachment of the detachable unit is detected using the load detection step and the presence / absence detection step in accordance with a result of communication by the communication step. Control method of forming apparatus. 18. When the communication in the communication step is not normally completed, the attachment / detachment of the detachable unit is detected in the load detection step and the presence / absence detection step, and the attachment of the detachable unit is detected. In this case, in the image forming condition setting step, the image forming condition stored in advance is set. 19. The method of controlling an image forming apparatus according to claim 11, wherein the detachable unit contains a consumable item used for the image formation. 20. The method of controlling an image forming apparatus according to claim 19, wherein the consumable item includes at least one of a recording material, a photoconductor, a recording medium conveyance belt, and a fixing device.