JP2001158552A - Image forming device having step-out detector for stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which can detect step-out of a stepping motor in a carrier system of the device without an encoder and which can also determine whether a jam has been caused by the step-out of the stepping motor. SOLUTION: In this image forming device, a measuring means measures a change in a current flowing in an exciting coil of a motor during a specific time period. When the measured change in the current exceeds a predetermined value, a step-out detecting means of this device determines that the motor is out of synchronism. A sheet detecting means is formed on a sheet path in a carrier system which is driven by the motor. When the motor is operating and the sheet detecting means continues detecting either a sheet or no sheet for a predetermined time period, a jam detecting means determines that a jam has occurred. When the step-out detecting means detects the loss of synchronism of the motor and the jam detecting means detects a jam, the device determines that the jam has been caused by the loss of synchronism of the motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus having a stepping motor out-of-step detecting device using a stepping motor which rotates by sequentially switching an excitation phase as a driving source of a recording paper conveying system.

[0002]

2. Description of the Related Art In a conventional image forming apparatus such as a copying machine, a DC motor or the like is used as a drive source of a paper transport system through which a recording paper actually passes, and the paper is transmitted through a transmission mechanism such as a gear or an electromagnetic clutch. A paper transport device that drives a plurality of transport rollers on a transport path has been widely used. In this paper transport apparatus, the paper transport control is realized by controlling the paper transport roller by opening and closing an electromagnetic clutch.

In recent years, there has been an increasing demand for high-speed processing in image forming apparatuses, and accordingly, there has been an increasing demand for high-speed paper transport in a paper (sheet) transport system. However, as a drawback of the paper transport control method of turning on and off the transport roller using a conventional electromagnetic clutch or the like,
The response speed of the electromagnetic clutch was slow, and this was a bottleneck for speeding up paper conveyance. On the other hand, a stepping motor has been widely used as a drive source of a servo system which is small and can be controlled in an open loop.

A stepping motor rotates a magnetic field by sequentially switching an exciting phase current of a winding, and a magnetic pole of a rotor attracts and repels the rotating magnetic field, thereby generating a torque. Is a motor that rotates while being dragged by the rotating magnetic field. Therefore, if the excitation phase is switched by inputting a pulse signal, the stepping motor rotates by the basic angle for one pulse of human power.

[0005] Therefore, in the stepping motor, open loop control is possible, and the system can be greatly simplified as compared with other servo actuators requiring a field-back system, which is advantageous in terms of cost. Become.

Therefore, in an image forming apparatus such as a copying machine, there is an image forming apparatus having a configuration in which stepping motors are used by the number of transport rollers as driving sources of a paper transport system and the transport rollers are driven without using an electromagnetic clutch. is there.

[0007]

However, a stepping motor can be constructed small and inexpensively. However, unlike a conventional servomotor, a stepping motor does not respond to a pulse signal input.
A phenomenon occurs in which the rotation of the rotor of the motor cannot be synchronized. This is called a step-out phenomenon. Generally, the step-out phenomenon occurs when the motor is overloaded with respect to the pulse rate commanded to the motor.

When a stepping motor is used in a paper transport system of an image forming apparatus, if a step-out phenomenon occurs during paper transport,
Paper conveyance stops, causing a new jam. Also, in the case of a jam caused by a stepping motor step-out, the jam can be detected only by the paper sensor, so that the cause of the jam may be a step-out of the stepping motor or a jam caused by another factor. It became difficult to identify what it was.

If a stepping motor or the like is provided with a sensor for detecting the rotation of the motor such as an encoder and the rotation of the motor is monitored, step-out detection is possible, but the system becomes complicated and the characteristics of the stepping motor cannot be utilized. . Therefore, detecting the step-out of the stepping motor at high speed without using a sensor is a great merit for the image forming apparatus.

Accordingly, an object of the present invention is to determine the out-of-step of a stepping motor without using an encoder or the like when a stepping motor is used in a conveyance system of an image forming apparatus. It is an object of the present invention to provide an image forming apparatus capable of identifying whether the cause is caused by a step out of a stepping motor.

[0011]

In order to achieve the above object, in an image forming apparatus according to the present invention, a motor drive for supplying a constant current chopper control system to a motor that sequentially switches an excitation phase such as a stepping motor and rotates. Means for counting the number of times of chopping is provided, and the number of times of chopping of the drive device within one cycle of the phase excitation signal is counted.

On the other hand, as a feature of the stepping motor,
When comparing the time of step-out with the time of driving according to the drive pulse (normal time), the number of times of chopping tends to increase at the time of step-out than at the time of normal rotation. Therefore, in the present invention, the number of chopping times measured by the comparing means is compared with a preset reference number, and when the measured number of chopping times exceeds the reference number, it is determined that the motor is in a step-out phenomenon. , And a step-out signal.

On the other hand, when viewed from the paper passing direction in the paper transport path, a paper detection sensor is arranged immediately after (immediately downstream) the paper transport roller driven by the stepping motor, and the paper detection sensor detects the paper. If the paper is not detected for a certain period of time from the time at which the paper is to be performed, it is determined that the paper is not being conveyed, and a jam occurrence signal is transmitted.

As another method for detecting the occurrence of a jam, a paper detection sensor is provided in front of (directly upstream of) a paper transport roller driven by a stepping motor when viewed from the paper passing direction in a paper transport path. If the paper detection sensor remains in the paper detection state for a certain period immediately after the paper detection sensor detects the paper, it is determined that the paper is not being conveyed, and a jam signal is generated.

Still another method for detecting the occurrence of a jam includes a first paper detection sensor and a paper conveyance roller in front of (immediately upstream of) a paper conveyance roller driven by a stepping motor in a paper conveyance path. Immediately after (immediately downstream) a second paper detection sensor, and if the second paper detection sensor does not detect paper after a certain period of time after the first paper detection sensor detects paper, It is determined that the sheet has not been conveyed, and a jam signal is generated.

When the control device of the image forming apparatus receives the step-out signal and the jam occurrence signal at substantially the same time, the control device determines that a jam has occurred due to the step-out of the stepping motor.

However, the number of times the motor current value changes (the number of times of chopping) depends on factors other than step-out, such as variations in the characteristics of the stepping motor, an increase in the ambient temperature of the stepping motor itself or the ambient temperature of the stepping motor, and a load on the stepping motor. It is considered that the fluctuation may be caused by such factors as fluctuation of the data.

Therefore, in the present invention, there is provided a counting means for counting the number of times that the change of the current value continuously exceeds the change of the current value of the step-out detection reference, and the number of counts exceeds the step-out detection reference number. In this case, it is determined that the stepping motor is out of step, and a step-out signal is transmitted by the step-out signal generating means.

In this case as well, a paper detection sensor is disposed immediately after (immediately downstream) the paper conveyance roller driven by the stepping motor when viewed from the paper passing direction in the paper conveyance path.
If the paper detection sensor has not detected the paper for a certain period of time from the time at which the paper should be detected, it determines that the paper has not been conveyed and sends a jam occurrence signal.

Alternatively, a paper detecting sensor is disposed (immediately upstream) in front of the paper conveying roller driven by the stepping motor when viewed from the paper passing direction in the paper conveying path, and the paper detecting sensor detects the paper. If the paper detection sensor remains in the paper detection state for a predetermined time immediately after the sheet is detected, it is determined that the paper is not being conveyed, and a jam signal is generated.

Alternatively, a first paper detection sensor is provided (immediately upstream) before the paper conveyance roller driven by the stepping motor in the paper conveyance path, and a second paper detection sensor is provided immediately after (immediately downstream) the paper conveyance roller. If the second paper detection sensor does not detect the paper after a predetermined time from the detection of the paper by the first paper detection sensor, it is determined that the paper is not being conveyed, and a jam signal is generated. .

When the step-out signal and the jam occurrence signal are received almost simultaneously, the control device of the image forming apparatus determines that a jam has occurred due to step-out of the stepping motor.

[0023]

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

(Embodiment 1) FIG. 1 is an internal configuration diagram of an embodiment to which an image forming apparatus of the present invention is applied. The image processing apparatus includes a main body image output unit 10 which is a device for placing a manuscript image on recording paper and outputs the same, a main body image input unit 11 which is a device for reading image data from a manuscript, and a main body image input unit 1.
1 is provided with an automatic document feeder 12 mounted on the upper part of the printer 1 and a sorter 13 for sorting and discharging copy paper discharged from the main body image output unit 10 into a plurality of bins (containers).

This image forming apparatus is a digital copying machine. The original is converted into pixels by a CCD of a main body image input unit 11, which is a device for reading image data from the original, read as image data into the apparatus, and necessary image processing is performed. After being performed, it is stored in the image memory. The image data is transferred to the main body image output unit 10, where the image is reproduced and copied on recording paper.

A main body image input unit 11 includes a light source 21 that scans while irradiating a document stacked on a document table on the upper surface of the input unit.
Is provided. The light source 21 obtains a driving force from an optical system motor (not shown) and reciprocates in the left-right direction in FIG. Light source 21
Is reflected by the stacked originals, and an optical image is obtained. The optical images are mirrors 22, 23, 24
And transmitted to the CCD 26 via the lens 25. The mirrors 22, 23 and 24 are driven integrally with the light source 21. The CCD 26 converts light into an electric signal, and the electric signal is further converted into a digital signal (image data).

The image data of the read original is subjected to various correction processes and image processing by a process desired by the user, and is stored in an image memory (not shown).

The main body image output unit 10 reads out the image data stored in the image memory, reconverts the digital data into an analog signal, and amplifies it to an appropriate output value by an exposure control unit (not shown). The signal is converted by the unit 27 into an optical signal. The optical signal is transmitted to the scanner 28 and the lens 2
The light propagates through the mirror 9 and the mirror 30 to irradiate the photosensitive drum 31 to form an electrostatic latent image. Toner is attached to the latent image, and the attached toner is transferred onto a recording sheet conveyed in the main body, and is further fixed on the recording sheet by a fixing roller 32. That is, image data is recorded on the recording sheet. It is sent to the sorter 13.

The sorter 13 is a sorting device installed on the left side of the main body image output unit 10,
A process is performed in which the recording paper output from is sorted into the paper discharge tray 33 and discharged. The paper discharge tray is controlled by the main body controller (not shown), and the output recording paper is discharged to an arbitrary paper discharge tray designated by the controller.

The paper feed trays 34 and 35 are provided at the lower part of the main body.
It is possible to accumulate recording paper to some extent. The control unit conveys the recording paper accumulated from the paper feed trays 34 and 35 and outputs an image. The paper feed deck 36 is a device installed on the left side of the main body image output unit 10, and can store a large amount of recording paper. Paper trays 34, 3
As in the case of 5, the recording paper accumulated by the control unit is conveyed and an image is output.

On the left side of the main body image output unit 10, a manual feed tray 37 is provided, which enables the operator to relatively easily feed a small number of copy sheets of arbitrary documents. This manual feed tray is also used when special recording paper such as OHP sheets, thick paper, and postcard size paper is used.

Paper transport rollers 38, 39, 40, 41, 4
Each of the rollers 2 has a role of actually transporting the recording paper when the paper is fed in the copy output process. Each paper transport roller is independently connected to a stepping motor as a drive source via a transmission device such as a gear. FIG. 2 shows the details of this part.

FIG. 2 is a detailed configuration diagram of a paper transport device in the image processing apparatus of the present invention. Here, the arrow in the figure indicates the direction in which the paper is actually conveyed.

In FIG. 2, reference numeral 101 denotes a stepping motor serving as a driving source of the paper transport device. A feature of the stepping motor is that the stepping motor rotates in response to the pulse power. In addition, since the rotation angle changes in proportion to the number of input pulses and the rotation speed changes in proportion to the input frequency, it is possible to drive the motor without forming a feedback loop. Due to such features, it is widely used as a driving source for open loop positioning control and speed control.

As a method of classifying stepping motors, a general classification is based on the structure of the motor. This includes a PM type (Permanent Type) in which the rotor is made of permanent magnets and a VR (Variable rel) in which the rotor is made of a gear-shaped iron core.
uctance Type) and HR type (Hybrid Type) in which the rotor portion is constituted by a gear-shaped iron core and a magnet.

As another classification of the stepping motor, there is a classification by the drive winding. The classification based on the drive winding is classified into two phases, three phases, five phases, and the like. The classification by the excitation mode includes one-phase excitation, two-phase excitation,
It can be classified into two-phase excitation and the like. In this embodiment,
A two-phase excitation type HR type stepping motor is employed.

Reference numeral 102 denotes a paper transport roller, which has a function of applying a force to and transporting the recording paper to be actually transported. The driving force from the stepping motor 101 is transmitted to the paper transport roller 102 through a gear, a shaft, or the like.

Reference numeral 103 denotes a paper detection sensor. Also 104
Is a photo-interrupter which plays a role of converting a reaction of the paper detection sensor into an electric signal. Although the paper passes in the direction indicated by the arrow in the figure, a paper detection sensor is provided immediately after the paper transport roller. When the leading edge of the paper passes the paper detection sensor 103, one end of the paper detection sensor 103 is pressed,
The other end has a shape that blocks between the light emitting unit and the light receiving unit of the photo interrupter 104.

Paper detection sensor 103 and paper transport roller 102
Is shorter than the length of the smallest recording paper usable in the image forming apparatus, and if the stepping motor operates normally and the paper transport roller 102 is driven, the paper transport roller 102 transports the paper and the motor is driven. The paper detection sensor 103 is designed to detect paper after a certain period of time has elapsed.

When the light emitting unit and the light receiving unit of the photo interrupter 104 are closed, the output signal from the photo interrupter 104 changes. The control unit of the image forming apparatus monitors the signal of the photointerrupter 104 at regular time intervals, and determines that the paper has been detected if there is a change in the output signal.

In the first embodiment, if the signal from the photointerrupter 104 is not a signal output in a state where paper is detected after a certain period of time after the motor is driven,
It is determined that a jam has occurred.

FIG. 3 shows a motor driving device built in the image forming apparatus which supplies power and controls the driving of the stepping motor used as the driving source of the paper transport device of the image forming apparatus in this embodiment. FIG.

In FIG. 3, reference numeral 101 denotes a stepping motor to be controlled; 201, a central processing unit (hereinafter referred to as CPU) for outputting a drive signal of the stepping motor;
Reference numeral 202 denotes a drive circuit that supplies a current necessary for rotating the stepping motor, 203 denotes a current sensor for measuring a current value, and 204 denotes an AD conversion for converting the current value measured by the current sensor into a digital signal handled by the CPU. Bowl, 20
5, a timer for measuring a sufficiently short time; 206, a ROM device storing a motor control program;
Reference numeral 7 denotes a RAM device used by the CPU as a temporary storage area.

In the motor driving device, the CPU 201 calls a stepping motor control program stored in the ROM device, and executes a stepping motor control program according to the instructions of the program.
It has a role of outputting a phase excitation signal, which is a drive signal of the stepping motor, to the drive circuit 202. That is, a phase excitation signal having a frequency corresponding to the target motor speed is output.

The CPU has a built-in timer 205, which can be called and used by a program, and is used for time measurement or when a specific interrupt process is generated for each cycle.

The step-out detecting process of the stepping motor having the characteristic configuration of the present invention is performed by the operation of the CPU 201. In the drive circuit 202, the constant current chopping control is implemented by hardware, and the current supplied to the stepping motor 101 is turned on / off in accordance with the phase excitation signal from the CPU 201 so that the current flowing through the motor becomes a constant current. It performs chopping control and supplies current to the stepping motor 101.

A current sensor 203 for measuring an actual current value supplied to the stepping motor 101 is mounted on the drive circuit 202, and the current sensor 203 outputs a voltage proportional to the measured current.

The AD converter 204 converts the analog voltage output from the current sensor 203 into a digital signal,
The current value information supplied to the motor is sent to U201. C
The PU 201 observes information from the current sensor 203 as an actual current of the stepping motor through the AD converter 204.

In recent years, a CPU in which an AD converter is integrated in the same package as the CPU has been widely provided. In this embodiment, a CPU 2 having a built-in AD converter is also provided.
01 is used.

The ROM 206 is a nonvolatile storage device. The ROM device 206 stores a motor control program.
Loaded into 1. The RAM device 207 is a CPU 201
Is a rewritable storage device for storing the calculation result and temporarily saving the calculation result during the calculation. In recent years, there has also been a CPU in which a ROM and a RAM are integrated in the same package as the CPU. When such a CPU is used, the ROM device 206 and the RAM device 207 can be omitted.

Next, differences in the characteristics of the actual current value between when the stepping motor is rotating normally and when step-out occurs will be described, and means for detecting step-out based on this characteristic will be described.

FIG. 4A is a graph showing the phase excitation signal and the current response when the stepping motor is rotating normally. FIG. 4B is a graph showing a phase excitation signal and a current response when a step-out occurs. 301
Is a phase excitation signal supplied to the drive circuit, 302 is a current response when the stepping motor is operating normally, and 303 is a current response when the step out of step.

When observing the graph 302 when the stepping motor is normally rotating, it can be seen that the current supplied to the stepping motor increases relatively gently, and therefore the number of times of chopping by the drive circuit is relatively small. On the other hand, when observing the graph 303 when the stepping motor loses synchronism, it can be seen that the current supplied to the stepping motor increases relatively sharply, and therefore the number of times of chopping by the drive circuit is relatively large.

From this, it can be seen that the number of times of chopping by the drive circuit with respect to the current supplied to the stepping motor tends to increase during step-out as compared with the normal state. That is, when the stepping motor is driven, the number of times of chopping is constantly observed, and when the number of times of chopping exceeds a certain reference number, it is predicted that a step-out has occurred. It is possible to constitute a key detection means.

However, the number of times of chopping by the drive circuit fluctuates due to factors other than step-out, such as variations in the characteristics of the stepping motor, an increase in the temperature of the stepping motor itself or the ambient temperature of the stepping motor, and variations in the load of the stepping motor. It is conceivable that the number of chopping times greater than the reference number is intermittently observed.

Therefore, if the number of times of chopping by the drive circuit is larger than the reference number within a necessary and sufficient time, that is, if the number of times of chopping continuously greater than the second predetermined number of times is counted, the stepping motor is disconnected. The present invention also employs a means for performing processing for determining that a tone is occurring.

Next, the actual processing flow of the step-out detection means will be described with reference to a flowchart. FIG. 5 is a flowchart for determining whether to call out-of-step detection processing in this embodiment. FIG. 6 is a flowchart illustrating a process of determining out-of-step detection according to the present embodiment.

Here, CNT1 is a variable for recording the number of times of chopping within the HIGH level of the phase excitation signal.
NT1f is a constant that stores a reference count for judging step-out detection in comparison with CNT1, CNT2 is a variable for recording the number of times CNT1 continuously exceeds the value of CNT1f, and CNT2f is a variable for recording CNT2. It is a constant that stores a reference number of times for comparing and judging step-out detection.
Err is a flag indicating that step-out of the stepping motor has been detected.

FIG. 5 is a flowchart showing a process of counting the number of times of chopping necessary for the process of determining the step-out detection according to the present embodiment.

The chopping frequency counting process is a process in which the process is called during the motor rotation from the step-out detecting process, the number of chopping times by the constant current control of the driving device is monitored, and the number is counted. When the process is called,
The process proceeds to step 1 (steps are denoted by “S” in the figure).

In step 1, a process for initializing CNT1, which is a counter for counting the number of times of chopping, to 0 is performed. Next, the process proceeds to step 2.

In step 2, the state of the phase excitation signal is observed. If the phase excitation signal is at the HIGH level, the process proceeds to step 3. If the phase excitation signal is at the LOW level, the process is continued until the phase excitation signal becomes the HIGH level. , Is performing a waiting process.

In step 3, the presence or absence of occurrence of chopping by the constant current control of the driving device is detected. If chopping has occurred, the process proceeds to step 4. If no chopping occurs, the process proceeds to step S5.

In step 4, a process of incrementing the value of CNT 1, which is a counter of the number of times of chopping, is performed, and the process proceeds to step 5.

In step 5, the state of the phase excitation signal is observed, and if the phase excitation signal is at the HIGH level, the process returns to step 3 to proceed. If the phase excitation signal is at the LOW level,
The chopping frequency counting process ends.

In the above-described process, the number of times of chopping in one cycle of the phase excitation is counted, and the value is stored in the counter CNT1.

Next, the step-out detection processing of the present invention will be described. FIG. 6 is a flowchart showing the out-of-step detection process of this embodiment. After the process is started, the process proceeds to step S11.

In step 11, a process is performed to determine whether or not the stepping motor is rotating. If the motor is rotating, the process proceeds to step S12. If the drive control of the motor is stopped, the out-of-step detection process ends.

In step 12, a process for initializing each counter of CNT1 and CNT2 is performed. After the completion of the initialization, the process proceeds to step S13.

In step 13, a process for calling the process of counting the number of times of chopping described with reference to FIG. 5 is performed. As described above, in the count processing of the number of times of chopping, the number of times of chopping in one cycle of the phase excitation is counted, the value is stored in CNT1, and the process returns to this processing. After returning from the chopping frequency counting process, the process proceeds to step S14.

In step 14, the number of times of chopping CN
Compare the value of T1 with the value of the reference number of times CNT1f.
If T1 exceeds the reference number of times CNT1f, step 1
The process proceeds to 5. If CNT1 is the reference number of CNTs
If it is 1f or less, the process proceeds to step S16.

In step 15, CNT1 is set to the reference number C
The value of CNT2, which is the second counting means for counting the number of times continuously exceeding NT1f, is incremented, and the process proceeds to step S17.

At step 16, a process for initializing the value of CNT2 is performed. After the initialization is completed, the process proceeds to step S19.

In step 17, the value of CNT2 which counts the number of times CNT1 continuously exceeds the first reference number CNT1f is compared with the value of CNT2f which is the second reference number. If CNT2 is the reference number CN
If it exceeds T2f, the process proceeds to step S18.
If CNT2 is equal to or less than the reference number CNT2f,
The process proceeds to step S19.

In step 18, it is determined that the stepping motor is out of step, and MtrErr is set to 1 in order to notify other steps of the stepping motor step-out. Then, the step-out detection process ends.

In step 19, a process for determining whether or not the stepping motor is rotating is performed. If the motor is rotating, the process returns to step 13 to proceed, and the step-out detection process is continuously performed until the driving of the motor is stopped. If the drive control of the motor is stopped, the out-of-step detection process ends.

Next, a jam detecting process in the paper conveying apparatus will be described with reference to FIG. In this processing, the paper is conveyed, and the processing is called by the control unit of the image forming apparatus at a timing slightly earlier than an ideal time when the paper detection sensor immediately after the paper feed roller is turned on.

The variable time is a variable indicating the time from the start of this processing until the sensor determines that a jam has occurred. flg is a variable indicating whether a jam has been determined based on the state of the sensor. When this process is started, the process proceeds to a step 101.

In step 101, the process of reading the output signal of the photo interrupter 104, that is, the paper detection sensor 10
3 to detect whether paper is present. After the processing is completed, the process proceeds to step 102.

In step 102, a process for branching the process is performed based on the determination of the state of the paper detection sensor 103 in the previous step 101. That is, if the recording paper is present on the paper detection sensor 103, the paper detection sensor 10
Since this indicates that the paper has been conveyed to the position 3, the process is terminated. If no recording paper exists on the paper detection sensor 103, the process proceeds to step 103.

In step 103, immediately after the start of the processing, since the paper has not reached the position of the sensor 103, ti
by the reference time stored in the
3 starts a timer device for observing whether or not paper is detected. After the timer is started, the process proceeds to step 104.

In step 104, the process of reading the output signal of the photo interrupter 104, that is, the paper detection sensor 10
3 to detect whether paper is present. After the processing is completed, the process proceeds to step 105.

In step 105, the process branches depending on the determination of the state of the paper detection sensor 103 in the previous step 104. That is, if the recording paper is present on the paper detection sensor 103, the paper detection sensor 10
Since this indicates that the paper has been conveyed to the position 3, the process is terminated. If no recording paper is present on the paper sensor 103, the process proceeds to step 106.
Proceed to.

In step 106, the count time of the timer device is compared with the value of the variable time to determine whether or not the reference time has elapsed since the start of the process. If the count time has not reached the value of the variable time, the processing of steps 104 to 106 is repeated. If the count time matches or exceeds the value of the variable time, the process proceeds to step 107.

At step 107, the paper detection sensor 103 detects the paper from the start of this processing, that is, a time slightly earlier than the ideal time when the paper detection sensor immediately after the paper feed roller is turned on to the reference time. This indicates that the paper was stopped at a position before the sensor even though the paper feeding operation was being performed because the paper could not be detected. Therefore, the variable jam indicating that a jam has occurred The flag is set to 1 and the process ends.

Next, the out-of-step jam determination process in the paper transport device will be described with reference to FIG. This process is performed when the paper transport device is transporting paper and driving the stepping motor.
Processing is performed at regular intervals. When the process starts,
First, the process proceeds to step 201.

In step 201, the variable jam indicating the jam determination in the jam detection processing described with reference to FIG. The state of flg is determined, and the process branches. If the variable jam
If the value of flg is 1, the process proceeds to step 202. If the variable jam If the value of flg is not 1, this processing is terminated.

In step 202, the state of the variable MtrErr indicating the step-out determination of the stepping motor 101 in the step-out detection process described with reference to FIG. 6 is determined, and the process is branched. If the value of the variable MtrErr is 1, the process proceeds to step 203. If the value of the variable MtrErr is not 1, this processing is terminated.

In step 203, the paper detection sensor 103
Since it is determined that a jam has occurred and that the stepping motor 101 has lost synchronization, it is determined that a jam has occurred due to the loss of synchronization of the stepping motor, and the synchronization loss processing is started.

The out-of-step jam process is a process of notifying that an out-of-step jam has occurred through information transmission means to an operator such as the operation unit of the present embodiment.

As described above, in the image forming apparatus using the stepping motor according to the present embodiment as a driving source for paper conveyance,
The step-out detection by the built-in motor driving device and the jam detection by the sensor make it possible to determine whether or not the cause of the jam is step-out of the stepping motor.

(Embodiment 2) FIG. 9 is a detailed block diagram of a paper conveying apparatus of Embodiment 2 in the image processing apparatus of the present invention, and FIG. 10 shows a procedure of jam detection processing in Embodiment 2. FIG. In the first embodiment, the paper detection sensor is disposed immediately after the paper transport roller, but in the second embodiment, as shown in FIG. 9, the paper detection sensor is disposed before the paper transport roller. Therefore, as shown in FIG. 10, the operation for detecting a jam is different from the operation for detecting a jam in the first embodiment. However, the other configurations (FIGS. 1 and 3) and the step-out detection operation and the like (FIGS. 5, 6, and 8) are the same as those in the first embodiment, and thus description thereof will be omitted. Hereinafter, with reference to FIG. 9 and FIG.
The image forming apparatus will be described.

Reference numeral 102 denotes a paper transport roller, which has a role of applying a force to and transporting the recording paper to be actually transported. The driving force from the stepping motor 101 is transmitted to the paper transport roller 102 through a gear, a shaft, or the like.

Reference numeral 103 'denotes a paper detection sensor. Also 10
Reference numeral 4 'denotes a photo interrupter which plays a role of converting a response of the paper detection sensor into an electric signal. Although the paper passes in the direction indicated by the arrow in the figure, a paper detection sensor is provided in front of the paper transport roller. The tip of the paper is the paper detection sensor 10
After passing through 3 ', one end of the paper detection sensor 103' is pushed, and the other end closes the light emitting unit and the light receiving unit of the photo interrupter 104 '.

The paper detection sensor 103 'and the paper transport roller 10
2 is shorter than the length of the smallest recording paper usable in the image forming apparatus, and if the stepping motor operates normally and the paper conveyance roller 102 is driven, the paper detection sensor 103 'detects the paper and It is designed so that the paper detection is turned off within a certain time.

When the light emitting portion and the light receiving portion of the photo interrupter 104 'are closed, the output signal from the photo interrupter 104' changes. The control unit of the image forming apparatus monitors the signal of the photointerrupter 104 'at regular time intervals, and determines that paper has been detected if there is a change in the output signal.

In the second embodiment, if the signal from the photo-interrupter 104 is a signal output in a state where the paper is detected for a predetermined time, it is determined that a jam has occurred.

Next, with reference to FIG. 10, a jam detecting process in the paper transporting apparatus according to the second embodiment will be described. In this process, the variable ti is set by the timer device during the paper conveyance.
Processing is performed for each time stored in me. The value stored in the variable "time" is configured such that the control unit sets different times depending on the size of the paper conveyed by the paper conveyance device.

The variable flg is a variable indicating whether or not the paper sensor has detected the paper before the time stored in the time. flg is a variable indicating whether or not a jam has been determined based on the state of the sensor. When the process is started by the timer device, the process proceeds to step 101 '.

In step 101 ', the process of reading the output signal of the photo-interrupter 104', that is, the detection of the presence or absence of paper on the paper detection sensor 103 'is performed. After the processing is completed, the process proceeds to step 102 '.

In step 102 ', the previous step 10
The processing for branching the processing is performed according to the determination of the state of the paper detection sensor 103 'in 1'. That is, if there is a recording sheet on the sheet detection sensor 103 ', the process proceeds to step 103'. If no recording paper exists on the paper detection sensor 103, the process proceeds to step 106 '.

At step 103 ', a process for branching the process is performed by judging the state of the variable flg. If flg is 1, the paper detection sensor 103 'has detected paper before the time stored in time. In this case, the process proceeds to step 104 '. Also, if f
If lg is 1, the paper detection sensor 103 has not detected paper before the time when time is stored. In this case, the process proceeds to step 105 '.

At step 104 ', the value stored in "time"
Paper remains on the paper sensor for
It is determined that Therefore, during operation when paper is being conveyed
It was determined that the paper had stopped near sensor 103 '.
Therefore, the paper jam occurs at the position of the paper detection sensor 103 '.
Is determined. Because the jam was determined, the variable jam f
A process of setting 1 to lg is performed.

In step 105 ', no paper jam occurs because the paper detection sensor 103 has not detected paper before the time stored in time. Further, in order to determine whether or not a jam has occurred in the next process of determining the state of the paper detection sensor 103 ', a process of setting 1 to a variable flg is performed.

In step 106 ', the paper detection sensor 10
Since paper no longer exists on 3 ', processing is performed to return each variable to the initial state.

After the end of steps 104 ', 105', and 106 ', this processing ends, and the processing is called after the time stored in the variable time.

(Embodiment 3) FIG. 11 is a detailed configuration diagram of a paper conveying apparatus of Embodiment 3 in an image processing apparatus of the present invention, and FIG. 12 shows a procedure of a jam detection process in Embodiment 3. 1 shows an example of the flowchart. Example 1
In the embodiment, the paper detection sensor is disposed immediately after the paper conveyance roller. In the second embodiment, the paper detection sensor is disposed before the paper conveyance roller. In the third embodiment, the two paper detection sensors are disposed. In use, the first paper detection sensor is disposed before the paper transport roller, and the second paper detection sensor is disposed immediately after the paper transport roller. Therefore, similarly to the first and second embodiments, it is possible to detect a jam using one of the paper detection sensors. However, as shown in FIG. 12, the jam is detected using the two paper detection sensors. Can be detected. The flowchart shown in FIG.
This is merely an example in the case where two paper detection sensors are used. Note that other configurations (FIGS. 1 and 3) and a step-out detection operation and the like (FIGS. 5, 6, and 8) are the same as those in the first and second embodiments, and a description thereof will be omitted. Hereinafter, FIGS. 11 and 12
Third Embodiment An image forming apparatus according to a third embodiment will be described with reference to FIG.

Reference numeral 102 denotes a paper transport roller, which has a role of applying a force to and transporting the recording paper to be actually transported. The driving force from the stepping motor 101 is transmitted to the paper transport roller 102 through a gear, a shaft, or the like.

Reference numeral 102 denotes a paper transport roller, which has a function of applying a force to and transporting the recording paper to be actually transported. The driving force from the stepping motor 101 is transmitted to the paper transport roller 102 through a gear, a shaft, or the like.

Reference numeral 103 "denotes a paper detection sensor.
Reference numeral 4 "denotes a photo-interrupter for converting the response of the paper detection sensor into an electric signal. The paper passes in the direction indicated by the arrow in the figure, but the paper detection sensor is installed immediately after the paper transport roller. The leading edge of the paper is the paper detection sensor 10
After passing through 3 ", one end of the paper detection sensor 103" is pushed, and the other end closes the light emitting portion and the light receiving portion of the photo interrupter 104 ".

The paper detection sensor 103 ″ and the paper transport roller 10
2 is shorter than the length of the smallest recording paper usable in the image forming apparatus, and if the stepping motor operates normally and the paper conveyance roller 102 is driven, the paper conveyance roller 102 conveys the paper and the motor The paper detection sensor 103 ″ is designed to detect paper after a certain time from being driven.

When the light emitting portion and the light receiving portion of the photo interrupter 104 "are closed, the output signal from the photo interrupter 104" changes. The control unit of the image forming apparatus monitors the signal of the photointerrupter 104 ″ at regular time intervals, and determines that the paper has been detected if there is a change in the output signal.

In the third embodiment, as shown in FIG. 11, a paper detection sensor 103 "and a photo interrupter 104" are installed before and after the paper transport roller 102 to observe whether or not paper exists on the paper transport roller. are doing.

Next, with reference to FIG. 10, a jam detecting process in the paper transporting device of the second embodiment will be described. In step 101 ", the output signal of the photo interrupter 104" of the first detection sensor 103 "is read, and the process proceeds to step 102".

In step 102 ", it is detected whether or not the first detection sensor is ON, that is, whether or not paper exists on the first paper detection sensor. Then, the first detection sensor is turned ON. At this time, the process proceeds to step 103 ", and if not ON, the process is terminated.

In step 103 ", the control waits for the elapse of a predetermined time (time during which the second detection sensor detects the paper in a normal operation).
Proceed to.

In step 104 ", a reading process of the second detection sensor is performed, and the flow advances to step 105".

In step 105 ", it is determined whether or not the second detection sensor is ON. If the second detection sensor is ON, it is determined that it is operating normally, and the process is terminated. Then, the process proceeds to step 107 ″.

In step 107 ", 1 is set to a variable jam_flg indicating that a jam has occurred, and the process ends.

[0120]

As described above, according to the image forming apparatus of the present invention, the motor control device for driving the stepping motor built in the image forming apparatus includes the chopping frequency measuring means and the measured chopping frequency. The comparison means compares the number of times of chopping with the preset number of times. If the measured number of times of chopping exceeds the number of times of reference, it is determined that the motor is out of sync. Step out detection is possible with.

On the other hand, when viewed from the paper passing direction in the paper transport path, a paper detection sensor located immediately after the paper transport roller driven by the stepping motor is used for a predetermined time from the time when the paper should be detected. , If no paper is detected,
Alternatively, if the paper detection sensor is located immediately before the paper transport roller driven by the stepping motor and the paper is detected for more than a certain period of time after detecting the paper, the paper further driven by the stepping motor If the paper is not detected by the second paper detection sensor existing immediately before the paper conveyance roller after a predetermined time after the paper is detected by the first paper detection sensor existing immediately before the conveyance roller, the paper is not conveyed. And a means for transmitting a jam occurrence signal, and the control device of the image forming apparatus determines that a jam has occurred due to step-out of the stepping motor when the step-out signal and the jam occurrence signal are received almost simultaneously. Has become. Thus, when a jam occurs, it is possible to determine whether the step-out of the stepping motor is the cause of the jam or whether another factor is the cause of the jam.

Furthermore, a motor drive device that determines that the motor has lost synchronism when the number of times of chopping continuously exceeds the predetermined number of times, which is equal to or more than the predetermined number of times, is obtained. Accordingly, when the number of times of chopping temporarily exceeds the reference number due to a factor other than the step-out phenomenon of the stepping motor, it is possible to exclude the step-out determination from the step-out determination and to perform a highly accurate step-out determination. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment to which an image processing apparatus of the present invention is applied.

FIG. 2 is a detailed configuration diagram of a paper transport device according to the first embodiment in the image processing device of the present invention.

FIG. 3 is a diagram illustrating a motor driving device built in the image forming apparatus that supplies power and controls driving to a stepping motor used as a driving source of a paper conveying device of the image forming apparatus according to the present invention; It is a block diagram.

FIG. 4 is a graph in which current supplied to the stepping motor is measured when the stepping motor is operating normally, and is a diagram for explaining a criterion for detecting step-out of the stepping motor. It is.

FIG. 5 is a flowchart illustrating a procedure of a task that monitors an excitation signal and calls a step-out detection process in the embodiment.

FIG. 6 is a flowchart illustrating a procedure of a step-out detection process according to the embodiment;

FIG. 7 is a flowchart illustrating a procedure of a jam detection process according to the first embodiment;

FIG. 8 is a flowchart illustrating a procedure of a step-out jam detection process according to the embodiment;

FIG. 9 is a detailed configuration diagram of a paper transport device according to a second embodiment in the image processing device of the present invention.

FIG. 10 is a flowchart illustrating a procedure of a jam detection process according to the second embodiment.

FIG. 11 is a detailed configuration diagram of a paper conveyance device according to a third embodiment in the image processing device of the present invention.

FIG. 12 is a flowchart illustrating an example of a procedure of a jam detection process according to the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Main body image output part 11 Main body image input part 12 Automatic document feeder 13 Sorter 21 Light source 22-24 Mirror 25 Lens (input system) 26 CCD 27 Optical irradiation part (laser) 28 Scanner 29 Lens (output system) 30 Mirror 31 Photosensitivity Drum 32 Fixing roller 33 Paper feed tray 34, 35 Paper feed tray 38-42 Paper transport roller 101 Stepping motor 102 Paper transport roller 103, 103 ', 103 "Paper detection sensor 104, 104', 104" Photo interrupter 201 CPU 202 Drive Circuit 202 Current sensor 203 A / D converter 204 Timer 205 ROM 206 RAM 301 Phase excitation signal 302 Current response graph at normal time 303 Current response graph at step-out CNT1 Chopping counter CNT2 Continuous counter CNT Flag indicating flag flg sheet detecting that indicates the generation of flag time jam detection time interval jam_flg jam indicating the occurrence of a reference value MtrErr step out of the continuous counting of the reference value CNT2f CNT2 successive counts of f CNT1

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F048 AA02 AB01 BA14 BB10 BC03 CC15 DA06 DB11 DC17 EB21 5H580 AA04 BB10 CA03 CA12 CB03 FA14 FA21 FA22 GG04 HH08 HH22 HH39 HH40 KK03

Claims (13)

[Claims] An image forming apparatus using a stepping motor that uses a stepping motor, which is driven by switching a phase excitation of an exciting current supplied to an exciting coil of a motor every time a drive signal is applied, as a driving source of a sheet conveying system. The change in the value of the current flowing through the excitation coil of the motor is measured by a measuring unit for a predetermined time, and the measurement result of the change in the current value of the measuring unit obtained by measuring during the predetermined time is a predetermined value. A step-out detecting means for determining that step-out has occurred when the value is exceeded is provided, and a sheet detecting means is provided on a sheet conveying path of a sheet conveying system driven by the motor,
Jam detection means for judging that a jam has occurred when the motor is driven and the sheet detection means detects a sheet for a certain period of time or does not detect a sheet, and the step-out detection means A stepping motor out-of-step detection device, comprising: control means for determining that the step-out is caused by a step-out of the motor when the jam detecting unit detects a jam when it is determined that step-out has occurred. Image forming device. 2. The image forming apparatus according to claim 1, wherein a current is supplied to an exciting coil of the motor by a constant current chopper control method, and a change in a current value measured by the measuring means is one phase of the motor. An image forming apparatus having a stepping motor out-of-step detecting device, wherein the number of times of current chopping in an excitation range is obtained. 3. An image forming apparatus according to claim 1, wherein said sheet detecting means is disposed immediately before or immediately after a sheet conveying means driven by a motor whose step-out is detected by said step-out detecting means. An image forming apparatus having a stepping motor out-of-step detecting device. 4. An image forming apparatus using a stepping motor which uses a stepping motor, which is driven by switching a phase excitation of an exciting current supplied to an exciting coil of the motor every time a drive signal is applied, as a driving source of a sheet conveying system. The change in the value of the current flowing through the excitation coil of the motor is measured by a measuring unit for a predetermined time, and the measurement result of the change in the current value of the measuring unit obtained by measuring during the predetermined time is a predetermined value. A step-out detecting means for judging that step-out has occurred when the value is exceeded, and a sheet detecting means comprising two sheet detecting sensors provided on a sheet conveying path of a sheet conveying system driven by the motor; The sheet is driven by the second sheet detection sensor after a lapse of a predetermined time after the sheet is detected by the first sheet detection sensor of the sheet detection means. A jam detection means for determining that a jam has occurred in a state where the motor has not been detected. An image forming apparatus having a stepping motor out-of-step detection device, comprising: a control unit that determines a jam caused by a key. 5. An image forming apparatus according to claim 4, wherein said first sheet detecting sensor of said sheet detecting means is provided immediately before a sheet conveying means driven by a motor whose step-out is detected by said step-out detecting means. An image forming apparatus having a stepping motor out-of-step detecting device, wherein the second sheet detecting sensor is disposed immediately after the sheet conveying means. 6. A stepping motor as a driving source of a paper transport system, motor driving means for sequentially switching an excitation phase of the stepping motor and supplying a current to the stepping motor by a constant current chopper control method, and the motor driving means. Chopping detecting means for detecting that chopping has occurred in the current flowing in the inside; counting means for counting the number of times of chopping within one cycle of the phase excitation signal by the chopping detecting means; A comparison unit that compares the set reference number of times, a step-out detection unit that determines that step-out has occurred when the number of times of chopping measured by the comparison unit exceeds the reference number, and the stepping motor is driven. The presence of paper immediately after the paper transport rollers on the paper transport path Paper detecting means for detecting the paper, and the paper if the paper detecting means does not detect the paper for a predetermined time from the time when the paper detecting means should detect the paper while the stepping motor is being driven. A jam detecting means for determining that a jam has occurred at a position in front of the detecting means; and a step-out of the stepping motor when the step-out detecting means and the jam detecting means respectively detect the step-out occurrence and the jam occurrence substantially simultaneously. An image forming apparatus having a stepping motor out-of-step detection device, comprising: control means for determining that the jam is the cause. 7. A stepping motor as a driving source of a paper transport system, motor driving means for sequentially switching an excitation phase of the stepping motor and supplying a current to the stepping motor by a constant current chopper control method, and the motor driving means. Chopping detecting means for detecting the occurrence of chopping in the current flowing in the first section, first counting means for counting the number of times of chopping within one cycle of the phase excitation signal by the chopping detecting means, and measurement by the first counting means. First comparing means for comparing the number of times of chopping with a first predetermined number of times, second counting means for counting the number of times the number of times of chopping measured by the first comparing means exceeds the first number of times, The number of times measured by the second counting means and a preset second unit A second comparing means for comparing the number of times, and a step-out detection for determining that step-out has occurred when the count value of the second counting means exceeds the second reference number as a result of the comparison by the second comparing means. Means, paper detection means for detecting the presence of paper immediately on the paper conveyance path with respect to the paper conveyance roller driven by the stepping motor, and the paper detection means while the stepping motor is driving If the paper detection unit does not detect the paper for a certain period of time from the time at which the paper should be detected, a jam detection unit that determines that a jam has occurred at a position in front of the paper detection unit; Control means for determining that a step-out of the stepping motor is caused by a step-out when the jam detecting means detects the occurrence of step-out and the occurrence of the jam almost simultaneously, respectively. An image forming apparatus having a stepping motor out-of-step detection device. 8. A stepping motor as a driving source of a paper transport system, motor driving means for sequentially switching an excitation phase of the stepping motor and supplying a current to the stepping motor by a constant current chopper control method, and the motor driving means. Chopping detecting means for detecting that chopping has occurred in the current flowing in the inside; counting means for counting the number of times of chopping within one cycle of the phase excitation signal by the chopping detecting means; A comparison unit that compares the set reference number of times, a step-out detection unit that determines that step-out has occurred when the number of times of chopping measured by the comparison unit exceeds the reference number, and the stepping motor is driven. The presence of paper immediately before the paper transport roller on the paper transport path Paper detection means for detecting the paper, the paper detection means detects paper while the stepping motor is driven, and if the paper detection means has been in the paper detection state for a certain period of time, a jam has occurred Jam detecting means for determining, and step-out detecting means and control means for determining that jam is caused by step-out of the stepping motor when the step-out detecting means and the jam detecting means respectively detect the step-out occurrence and the jam occurrence almost simultaneously. An image forming apparatus having a stepping motor out-of-step detecting device, comprising: 9. A stepping motor as a driving source of a paper transport system, motor driving means for sequentially switching an excitation phase of the stepping motor and supplying a current to the stepping motor by a constant current chopper control method, and the motor driving means. Chopping detecting means for detecting the occurrence of chopping in the current flowing in the first section, first counting means for counting the number of times of chopping within one cycle of the phase excitation signal by the chopping detecting means, and measurement by the first counting means. First comparing means for comparing the number of times of chopping with a first predetermined number of times, second counting means for counting the number of times the number of times of chopping measured by the first comparing means exceeds the first number of times, The number of times measured by the second counting means and a preset second unit Second comparing means for comparing the number of times, and step-out detection for determining that step-out has occurred when the count value of the second counting means exceeds the second reference number as a result of comparison by the second comparing means. Means, paper detection means for detecting the presence of paper immediately before the paper conveyance roller driven by the stepping motor on the paper conveyance path, and the paper detection means while the stepping motor is driving Jam detection means for detecting paper and judging that a paper jam has occurred if the paper detection means has been in the paper detection state for a certain period of time; and the step-out detection means and the jam detection means have step-out occurrence and jam occurrence, respectively. And control means for judging that the jam is caused by the step-out of the stepping motor when the stepping motor is detected almost at the same time. Image forming device. 10. A stepping motor as a driving source of a paper transport system, motor driving means for sequentially switching an excitation phase of the stepping motor and supplying a current to the stepping motor by a constant current chopper control method, and the motor driving means. Chopping detecting means for detecting that chopping has occurred in the current flowing in the inside; counting means for counting the number of times of chopping within one cycle of the phase excitation signal by the chopping detecting means; A comparison unit that compares the set reference number of times, a step-out detection unit that determines that step-out has occurred when the number of times of chopping measured by the comparison unit exceeds the reference number, and the stepping motor is driven. Immediately before and after the paper transport roller on the paper transport path First and second paper detecting means for detecting the presence of paper later, and the second paper for a predetermined time after the first paper detecting means detects paper while the stepping motor is being driven. If the detecting means does not detect the paper, a jam detecting means for determining that a jam has occurred at a position between the first and second paper detecting means; and the step-out detecting means and the jam detecting means, respectively. And control means for judging that the jam is caused by the step-out of the stepping motor when the occurrence of the jam is detected almost simultaneously. An image forming apparatus having a stepping motor step-out detecting device. 11. A stepping motor as a driving source of a paper transport system, a motor driving means for sequentially switching an excitation phase of the stepping motor and supplying a current to the stepping motor by a constant current chopper control method, and the motor driving means. Chopping detecting means for detecting the occurrence of chopping in the current flowing in the first section, first counting means for counting the number of times of chopping within one cycle of the phase excitation signal by the chopping detecting means, and measurement by the first counting means. First comparing means for comparing the number of times of chopping with a first predetermined number of times, second counting means for counting the number of times the number of times of chopping measured by the first comparing means exceeds the first number of times, The number of times measured by the second counting means and a predetermined second A second comparing means for comparing with a quasi number of times, and a step out which determines that step out has occurred when the count value of the second counting means exceeds the second reference number as a result of comparison by the second comparing means. Detecting means; first and second paper detecting means for detecting the presence of paper immediately before and immediately after the paper transport roller driven by the stepping motor on the paper transport path; and If the second paper detecting means does not detect the paper for a certain period of time after the first paper detecting means detects the paper while the paper jam occurs, a jam occurs at the position between the first and second paper detecting means. Jam detection means for determining that step-out has occurred, and when the step-out detection means and the jam detection means detect the occurrence of step-out and the occurrence of jam almost simultaneously, respectively, to determine that the step-out of the stepping motor is caused by the step-out. An image forming apparatus having a stepping motor step out detector, characterized in that it comprises a control means. 12. An image forming apparatus according to claim 6, wherein a step-out detection time detected by said step-out detection means and a jam occurrence time detected by said jam detection means are recorded. An image forming apparatus having a stepping motor out-of-step detecting device, characterized by having a history storing means for storing as step data. 13. An image forming apparatus according to claim 6, wherein a plurality of stepping motors are used, and control and step-out detection are performed independently for each stepping motor. An image forming apparatus having a stepping motor out-of-step detecting device, which is capable of being performed.