JPS59221748A - Image forming device - Google Patents

Abstract

PURPOSE:To combine common program modules to realize a new function by editing tasks by a monitor for each generation of an event and macrocalling. and executing successively each fractionated task. CONSTITUTION:The program of an image forming device such as a laser beam printer containing a microcomputer, a facsimile, etc. is converted into a module every task. Then a task group is formed by a monitor 1. When the using right of a microprocessor MPU is sent back to the monitor 1, this using right is first entered to a header 2 to have a test to check whether or not a phenomenon to be urgently processed is produced. If this flag is set up, the processing under execution is interrupted to carry out immediately the tested phenomenon. An I/O relocation table 3 is provided to give flexibility to the hardware every application. When the timing pulses fed from outside are counted up to a set level, a task schedule is set. Then the task groups are formed to execute tasks successively.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an image forming apparatus, and more particularly to a software configuration of a microcomputer sequence.

BACKGROUND ART Conventionally, in the development of image forming apparatuses such as microcomputer-equipped devices, laser beam printers, facsimile machines, ocit% electronic files, etc., a dedicated program has been developed for each machine, unit, etc. design. Therefore, it was only used once and could not be extended to other models, and the development ability was poor.As the program structure did not separate the sequence control system and automatic control system depending on the monitor, they were all mixed in the same program. . Also, many things depend on the personality of the individual programmer, and there are cases where only the person who created it can understand the content, and the length and shortness of the program,
There was a lot of variation in the time required for divac. Furthermore, there was no flexibility in changing the specifications, and adding or changing programs meant building the program configuration and having to rewrite it from scratch.

Purpose In view of the above points, it is an object of the present invention to provide an image forming apparatus having a means for modularizing a program for each task and organizing a group of tasks to be processed according to the occurrence of an event.

Another object of the present invention is to configure a monitor with a header for detecting the occurrence of an abnormality or an event, and means for counting timing pulses, controlling zero-crossing pulses, and controlling terminating. .

Another object of the present invention is to provide a monitor for managing programs;
An object of the present invention is to provide an image forming apparatus having means for organizing program modules subdivided into tasks according to the occurrence of an event.

Another object of the present invention is to create a long program by dividing it into individual tasks, and to control these tasks using a dummy program, which makes complex programs easier. It's about creating.

Another object of the present invention is to make the monitor of the image forming apparatus resident on the memory of a one-chip microcomputer (hereinafter referred to as MPU) or on the external memory of the MPU in order to facilitate program development and operational management. , solid-state monitor, or silicon monitor.

EXAMPLES Hereinafter, examples to which the present invention is applied will be described in detail with reference to the drawings.

The purpose of the present invention is to create programs by dividing them into individual tasks for each task, and the execution management program is in charge of controlling these programs. Management program o,
It is called s. Here, we will call a small real-time monitor (hereinafter referred to as real-time monitor). A real-time monitor is a monitor program that controls multiple tasks in parallel using one MPU. Note that this individual work is called a task.

Next, the present invention will be described using a copying machine as an example of an image forming apparatus. In the real-time processing of a copying machine, programs that are extremely urgent and programs that have relatively few time constraints coexist.

For example, abnormality detection, thermal runaway of heaters in processing tasks, etc. have extremely high priority, and a certain tie 1 is located at a relatively low level in the sequence control performed by Mink. Therefore, in order to perform harmonious scheduling, priorities are divided into appropriate levels and a control method between these levels is determined. In the task scheduling method of this embodiment, a header is provided in the monitor and these tests are performed with the highest priority to switch tasks.

Next, FIG. 1 shows the structure of the real-time monitor in this embodiment. The monitor of this application consists of a header, an I10v location table, an I10 buffer, a timing pulse count control, a zero-crossing pulse count control, and a task schedule control, as shown in the figure.

Functions such as creation, deletion, synchronization, and communication of tasks are performed by this monitor. The structure of the monitor will be explained next.

? The sequence control shown in J photo i counts the encoder pulses generated by the rotation of the motor or the rotation of the drum, calls the processing program (sub71.-cheer) according to this integrated value, and advances the sequence. . The monitor of this embodiment basically controls the task schedule using this pulse count as the core.

Next, the contents of the monitor will be explained.

1 in FIG. 1 is a monitor, and 2 is a header.

MP[When the right to use J is returned to the monitor, first write header 2) IJ. Also, when the power is turned on and the program starts from address 0, when the monitor 1 is first entered, an entry is made to the header 2 in the same way. here,
Test flags or status to check whether an event that should be handled urgently has occurred or not. Line b1: If these flags or status are set, interrupt the process being executed and perform the event tested here. process immediately. Therefore, the events tested here will forcibly change the schedule of the task. Examples of events here include overheating of the heater, exposure lamp turned on and no brim, opening of the door (open door), etc. In this case, a serious abnormal phenomenon such as a jam near the fusing unit or a motor locking is detected.

1 (Figure 3 shows the I10 relocation table. In order to provide flexibility in the hardware for each application (corresponding to the machine model), the relocation table is used. This allows the configuration of the hardware to be different. Even if you are running a program, you can use only macro instructions without changing the program structure each time.
You can allocate number 10. When initializing the program, select an arbitrary port (corresponding to the hardware configuration at that time) from the port location table and assign it to an absolute address. - A macro instruction is provided to set the β relocation table (not shown) to an absolute address. (1) The 10 buffer is a buffer corresponding to a port, and input/output is performed via this buffer. It is also possible to perform Ilo Q bit manipulation on the on-chip port of the one-chip MPU, and there is a corresponding register for this, which can be achieved by manipulating this register. In this case as well, this is done via a buffer, and if it is an on-chip port, the Ilo output is performed by bit manipulation. Also, Figure 2 shows M
It is a figure showing the relationship between PU, an encoder, and a zero cross pulse.

The sequence control of the o-lute and 4J1 copying machine is performed using the timing pulse generator 6 shown in Fig. 1.
Sets and resets the load by counting the encoder pulses generated by the sensor, and tests the signal input from the sensor to determine the condition of the machine.
We are doing TOP.

Figure 2 5 shows an MPU (microcomputer'), and in this example, it uses an Intel 8751.
It has a built-in 2-channel event counter with 1Fi 16-bit capacity. One channel (TO terminal) of these is used for inputting all the encoder pulses 6. This event counter counts LJP node-wise regardless of the execution of the MPU program, so the execution of the MPU is not interrupted due to the counting, and there is no built-in event counter. If an MPU is used, a timing pulse is input to the interrupt, which is processed by an interrupt service routine program. In this case, each time a timing pulse is input, the currently running program is interrupted and the timing pulse is counted.1For example, if the timing pulse has a pulse width of 2m (8), an interrupt will be generated every 2m5ec. The program will be interrupted. The faster the pulses are linked, the more frequently interrupts occur and the execution program may be interrupted.

Therefore, it is not a wise method to count timing pulses, which uses interrupt terminals for faster pulses. or,
When using an extremely low-cost MPU, interrupts can also be
If you do not have a built-in counter, you can input pulses to the I10 boat and use software to recognize and count the pulses by polling. In this case, only relatively slow pulses can be counted. What means to use for timing pulse sensing may be selected depending on the size and purpose of the system.

The INT terminal of the MPU 5 shown in FIG. 2 is used for interrupting zero-cross pulses from the zero-cross pulse generator 7 by using an event counter to count timing pulses. The zero-crossing pulse detects the zero-crossing point of the variable current AC wave, inputs it to the MPU, recognizes it, and uses it for power control and timer counting. Interrupt IN'l”φ
In the case of 8751, edge detection and level detection can be performed by the program, and in this case, it is set to edge detection. It is recognized by the falling edge of the zero-crossing pulse. Timing pulses counted using these means are compared and verified within a monitor, and as a result, task scheduling is determined.

Figure 3 is a diagram showing the relationship of comparison and verification of timing pulse count values. Timing pulses are input from the outside as 0 event inputs, and these are the falling edges (
(or a rising edge) is detected, synchronized with an internal clock, and stored in the Cφ register, which is a 16-bit counter. Test the contents of this counter register Cφ in this monitor and set it to a predetermined value (n, ~nryl).
is checked to see if it has been reached. Then, a branch is made to the task schedule control that has reached a predetermined value, and here the status of the execution task is established and scheduling is established.

Similarly, the task is also deleted, which means the end of execution. In Figure 3, in the comparison and verification judgment, the reason why pulses are added by +1 (n, +1) and verification is performed again is because the timing pulse count is fast in order to ensure the reliability of count verification. This is a countermeasure in case a mistake occurs due to some factor (noise, processing delay due to program execution time).

In this way, the timing pulses arriving from the outside are counted in the monitor and the set value (for example, 40, 60, 100, etc.) is counted.
．． 200. ......1,100...), the K (task creation, deletion) task schedule is set to perform some processing. This counter register is used for this verification and comparison. During the program routine, the delimiter of one cycle of the copying sequence (for example, photoreceptor drum 1
When the photo sensor detects the end or start of the l segment (if it is a rotating belt-shaped photoreceptor), it is reset and then UP again from φ. In the case of a seamless photoconductor, the counted value is set to a predetermined value (for example,
When it reaches 1,200 or 1,500), Karan) TJ
It may be set so that an internal interrupt is generated when P is reached, and the counter register is reset when it reaches a predetermined value (one cycle). Setting of count values for creating and erasing tasks is done by macro instructions, for example, Y.
If the data is set as PSCOT=too, the task will be activated (created, deleted) when the number of pulses reaches 100. This task schedule control will be described later.

FIG. 4-1 is a diagram showing the generation of zcp (zero cross point) from alternating current AC. The zero-crossing pulse (ZCP) detected by the AC wave is input to the interrupt signal, and its falling edge (it can also be the rising edge) is detected and an interrupt signal is generated. cycle, i.e. the capital is thinner, e.g. MPU
internal pulse (1μ5ec when using a 12 MHz crystal in the case of pulse 8751 divided from a crystal)
If you count the interval by 50.60) (the frequency of Z can be discriminated, point a is the true ZCP. Father,
ZCP is the zero cross point trigger control of AC power, PWM (pulse width) of AC power, phase side (fLll
, generation of a timer by counting ZCP, task schedule control (scheduling of tasks according to the arrival of ZCP), etc.

FIG. 4-2 shows an enlarged view of the diagram shown in FIG. 4-1. a
is a true ZCP as in FIG.

Further, 1p is a period. The pulse width of the ZCP largely depends on the circuit configuration and is about 50 to 500 μ degrees.

Point a, which is the true ZCP, can be considered as the midpoint of the pulse width. Therefore, calculation is possible by starting the υ internal counter at the detection point C and counting the kan.The end of the gu is as follows.
It can be tested on a port by fanning it out to a port, or it can be input into another interrupt by a rising edge. be. If Z CP can be calculated by calculating the dark, b can be calculated in the same way. Just start the counter from C, decide the range of b, and set a flag on the status ZPFLG at the zero cross point only during that time.

Figure 4-3 shows the structure of the false cross pulse control registers ZPFLG, ZCPCOl, and ZCPCO2.

A zero-cross pulse control flowchart is shown in FIG. 4-4.

s'rgp-1: Z CP An interrupt is generated by point a. Internal counter C1 starts. Activation of this counter generates and erases a zero-crossing flag. The internal pulse of Intel MP08751 is 1μ passing (zc
control the flag of p).

5TEP-2: LaI3. of register ZP FLG. bφ
When performing a zero cross trigger, setting a flag on I1
Test this flag with 0 control and set 1 here
If you trigger when the flag is set, you can perform a zero cross trigger.This flag is set only for the 200μ type (if you want to improve accuracy, you can set it to be shorter than this).

S'J'EP-3: Wait for internal interrupt, this is 5TE
The value of the counter set in P-1 (in this example, 200μ(
3), that is, the 200th shot), an internal interrupt occurs.

5TEP-4: Since the predetermined value has passed, erase the flag set on bφ of ZPF'LG. In this example, zero cross triggering is possible for 200μ. As mentioned earlier, we want to improve the accuracy. In this case, the set value of the internal counter of s'i'Ep-1 may be selected.

In Figure 4-4, a predetermined b is measured, and this fourth step means that the trigger range of b has ended, and the flag is cleared. ) is a fixed value (cannot be calculated yet). After the fixed value is detected, it is set to a value such as the 100μ formula, and after it is calculated, it is reset to a new value. Immediately after the power is turned on, the load is not energized for the first time, so there is no effect on anything else.

S'l'BP-5: Test whether the power is turned on immediately or not.

s'rgp-6: y, CI) Perform pulse width measurement.

5TIDP-7: Measure period t, 50.60Hz
.

Perform frequency discrimination.

8TluP-8: Calculate the trigger range. After C is detected, perform a predetermined count and perform appropriate calculations. The narrower the interval between b, the greater the noise suppression effect at the time of triggering. However, the program From the relationship of execution time,
The slow MP[J will be surprised to freeze when he grabs this flag. The point is that it is determined based on the relationship with the speed of the MPU.

5TEP-9: Counts Z CP, and can configure a timer according to this count value.
4-3 Figure 1tC shown f K, ZCPCOI 1dZc
Similarly, the lower 8 bits of the P counter, ZCPCO2, indicate 8 bits that are high. +lL every time ZCP pulse arrives,
Te ZCPCOi K When ZCPCO is full and +1, when a carry occurs, ZCPCO
It will be raised to 2. In this way, the zero-cross pulse counter is stored in 16 bits of ZCPCOI and ZCPCO2.

, in Figure 4-3.
: Zero cross trigger flag. In Figure 4-2, when bφ of ZPFLG is set to 1 only during b (zero cross) IJ (with respect to load), 01JTPU
In T's program routine, shift ZPFLG to the right, test that the flag is set, and trigger.

As mentioned above, timing pulse count control is composed of encoder pulses and zero cross pulses (ZCP) Ic that arrive from the outside, and this count value is read to perform sequence or schedule control of tasks in an automatic control system. Ru.

A flowchart of a typical copying process is shown in FIG. In Fig. 5, in S'l''gP-501, when the power is turned on by the user and the power system is still cut off, MPtJ performs an initial check and initialization. Is there any danger in energizing the system? Is there any jammed paper near the heater? Is the heater's 0A detection element broken? Is the exposure lamp control circuit normal?
Turn on the power and check to see if there are any abnormalities.

Next, initial settings are made for the mechanical parts of the machine. This is usually called positioning, and this is used to return the slider to a predetermined position when it is not at its home position, or to return it to its initial position if there are cams, rings, etc. Set to . Also this is 5
Not only TEP-501 but also 5TEP-503 is tested in the waiting state before copying. If there is no problem with energizing the power system at this point, the power system relay for energizing the load closes and the state becomes ready for energization.

In 8TEl'-502, the power system becomes AfE enabled, a power source is connected to the heater, and the temperature is raised to a predetermined fixing temperature. Naturally, the condition of the machine is checked until the specified temperature is reached.

5TEP-503 is in a standby state where the copy is not available. The heater in the fixing section is controlled to a predetermined temperature.
In this routine as well, abnormal conditions are constantly monitored. The display shows the set number [l], and key inputs are scanned and are waiting for the operator's command.

In 5TEP-504, a copy start key is tested. When the copy start state is reached, the copy process is immediately started.

In 81'EP-505, a copy process necessary for copying is executed. Stripping, exposure, development, transfer, static elimination cleaning, and registration.

Separation, conveyance, fixing, etc. are performed based on a series of sequence programs.

5TEP-506 tests the completion of the copy process. When the set number of sheets matches the number of copies, a copy end flag is set and the process proceeds to a processing routine after copying is completed.

5TEP-507: In the post-process after copying is completed, the g-light body is cleaned in preparation for the next copy. If the next copy becomes possible during this processing step, an indication that copying is possible is issued even if this step is not completely completed. 5TEP- as soon as it is recognized that the copy start key is ON.
Entry to the SOS replication process routine.

As described above, copy modes exist depending on each state, and execution tasks are combined depending on the mode. This execution task is called by a macro instruction. Therefore, the execution task is configured according to the setting of the task schedule control mode in this monitor.

Next, the task schedule control 8 shown in FIG. 1 will be explained. Here, we perform task schedule switching, execute tasks according to a certain copy mode, sequence order, but if an emergency abnormal phenomenon or an interrupt occurs, this task schedule will change the priority order. and carry out actions with a high level of urgency.

Next, FIG. 6 shows the status checked in the task schedule control of this monitor. Abnormal mode, diagnostic mode (status), and steady mode are tested. Abnormality mode (serious abnormality) is executed with highest priority in the monitor. Since the status is checked in the header 2 of FIG. 1, it is determined whether any abnormality has occurred, and an execution task is immediately set up and executed. In this case, as soon as it is tested in Helada 2, the status MAI, FN
call. The status of the steady mode is 1 byte, and the execution order is determined from the M813C (from b7) side. If there are many tasks, the number of bytes can be increased by 1 if necessary.The diagnosis mode will be described later.

fA7 Figure u is a flowchart of task schedule control (hereinafter, this monitor will be referred to as a task scheduler).

Si'JnP-700: If abnormal mode (major abnormal mode) is tested in the header - immediately K 5 in the monitor
Jump the TEP-101 and check for any abnormalities (heater overheating, halogen lamp not turning on, etc.). Normally, status MALL! in FIG. 6 is used here. 'N, perform the ABNOM test.

ST] Dr-701: If an abnormality (blood or minor abnormality) is tested here, the abnormality processing task is immediately started from here.
The assembly process is executed at TEP-108.

In this case, the contents to be processed will naturally differ depending on the degree of abnormality in the military and light vehicles.

5TEP-702: Perform a steady mode test, that is, recognize which stage in FIG. 5 is being processed by MPIJ and the mode order.

5TEP-703-704. 706: Check the mode and send the task according to the mode s'rgp-tos
It is combined in.

5TEP-705: This is the stage where sequence control is performed in the copy mode. When this mode is tested, the control order of tasks is formed according to the count value of the timing pulse during the monitoring. This is called and the tasks in the copy mode are organized according to the count value of the timing pulse of the 08TEP-707 sequence control, which combines the execution of the tasks.Based on this, the execution tasks are configured.

5TEP-708: Configure tasks according to the mode. I have described a zero or more task scheduler that selects necessary tasks from a group of tasks according to the mode and arranges the execution order.Those that require urgent task switching are tested by the occurrence of an event in the header, and other tasks are The status is set and reset in the processing routine by the execution of the process and regular events (for example, when the fusing temperature reaches a predetermined level and copy is enabled, or when the copy start or stop button is pressed). It is done.

Table 1 shows the status and steady mode (CPMOD) for determining the task schedule shown in FIG. 6 above. Test the CPMOD in the monitor and organize the tasks necessary for the flagged mode. In the example of this application, there are eight stages in the steady mode, but if necessary, if there are many modes and stages, CPMOD may be expanded to 2 bytes or 3 bytes.

Table 1 CPMOD MPU CPMOD, i 7 # Yumv -Y1tC
IV[0VIJ L.

By sequentially rotating to the left and testing the carry, you can determine which bit status is 0 or which bit is set. Organize the necessary tasks and make macro calls when you are busy. In this case, there is relatively little urgency, so s b? There is no need to set an emergency stop flag etc.

Table 2 shows the status of the abnormality mode shown in Figure 6, especially the serious abnormality mode + VULFN0.When this is tested in the header, it immediately calls MULF"N to test what kind of abnormality it is. The processing task is immediately called.Whenever these buttons are pressed, the power system must be immediately shut off to prevent a disaster.In MULFNfC, the bφ bibin is when the operator presses the front cover, upper wall, or alligator. When raised, it touches the filled part,
This is to prevent electric shock and is different from a hardware malfunction.

Table 2 M, ULFN (major abnormality) Table 3 shows status AHN of minor abnormality in abnormal mode
Indicates OMI and ABNOM2. When these are tested, if copying is in progress, the copying operation is stopped as soon as the process currently in progress is completed (called a cycle stop), and the next copying is prohibited. -9-ply). ABNOM
1 is a jam. If you test it, you will find out which drain the jam occurred in. Furthermore, as you O-tit, you will be able to determine where and where the jam occurred. So b6. b, or 11. If Jamstitas is standing at , the previous copy is fixed.

If the copy is being ejected, first eject the copy completely and then stop the machine. Naturally, if a jam occurs in the fusing or paper ejecting section, the paper feed must be stopped and the machine must be stopped immediately.

Check the ABNOM214 supply 1 When testing the b7 flag, if ■ stands, it means the supply is gone. In this case, the machine will not stop immediately or the cycle will not stop, but if the specified size paper is on top. , the cycle is stopped only when the lower cassette is empty, and the upper cassette is empty.

When there is paper of the same size in the lower cassette, when the upper cassette runs out of paper, paper feeding from the lower cassette immediately begins, allowing for limitless paper feeding to make large quantities of copies. Regarding the toner and photoconductor, a warning is issued by display or sound (see Table 4) DIAGN (circuit diagnosis), but it does not stop, and the copy quality deteriorates, but it can still be used.

Table 4 is the status testing diagnostic mode. Each circuit has a diagnostic sensor, and diagnostic signals from these sensors are tested. When uncontrollable due to circuit failure or abnormal current or 1 voltage is detected, or when no output is output (power supply circuit, etc.) or when the lamp is not emitted, the status is set in the specified bits of these DIAGN. , b6
．． is an abnormal flag, and when status is set on any of bφ to b14, ') +++ K flag is set.

The entry names of the next task and its macro call will be explained with reference to Table 5. The copying machine to which the present invention is applied has 28 tasks, and each task can be called by calling a macro entry name. Then, each task is made into a block, which is used as a single macro to configure each stage of the copying process (for example, a pre-copy check routine, a copying process execution routine, etc.).

Table 5 Hereinafter, the functions shown in Table 5 will be simply explained.

The T-1 is a control program that displays the status of the Tawara Photographer. (Depending on the specifications of the machine, it performs dynamic scan control using a dot matrix display board, LCD, 7-segment LED, etc.) , the machine status of each copying stage, and responses to user commands.

T-2u, scan the key switches on the operating section to test the operator's input status.

In addition, input is permitted or prohibited depending on the copy stage and mode. For example, changing the number of copies setting during copy run is prohibited, and the clear key is pressed to stop FiA4G (emergency stop).
0T-3, which allows key input, initializes the mechanical parts and drives the photosensitive drum, scanner, cam, and other mechanical parts to return to their home positions. In this case, test the home position sensor, and if it does not return to the home position even after driving for a predetermined period of time, it will be considered abnormal. In this case, an abnormality signal is issued and the operator is notified by display or voice.

T-4 uses input information from a photo sensor, which is a paper size detector placed at the paper feed pulse, a mechanical switch, etc.
Checks the passage of paper inside the copying machine, checks the paper feed section, registration, separation, paper ejection, etc. Also checks the remaining paper during the initial check before starting copying. In this case, the paper inside the machine is ejected. If the paper is not ejected due to a jam or the like, an error occurs.

The rv-5 is ']'-4's LJAMI'AIC engine check, heater, lamp disconnection, temperature detection element failure, door opening, motor lock overheating, encoder failure that generates timing pulses. .

Test for abnormalities in the optical system, developing system, and photoreceptor using senna to detect abnormality modes within the machine.

T-6 has jams, density abnormalities, lamp abnormalities, unexpected case opening, no paper, no toner, motor locks,
Excessive? Depending on the degree of abnormality such as E flow or overload, abnormality processing such as emergency stop, cycle stop (stop after process completion), prohibition of restart, etc. is performed. The details of the abnormality are notified to the operator using means such as a display on the operation panel and a sound bar. When the content of the error is corrected and the mode returns to copy-ready mode, the photoconductor is cleaned depending on the severity (such as a jam during development or the machine stops before cleaning is completed), and then copy-ready mode is restored. Move to.

Tf7 controls stopping, starting, etc. of the motor depending on the state of the machine.

T-8c, servo control reads encoder pulses to detect position, control speed,
Performs forward/reverse rotation and short return according to the paper size signal.

The T-9 is controlled by a pulse motor in an open-loose manner to move the lens in response to inputs from the operation keys, such as borrow, 1. (reduction, enlargement).

T-1ou controls the paper feed from the upper and lower two cassettes, and automatically switches the paper size selected by the operator to the same size in the upper and lower cassettes to prepare for severe copying (limitless). paper feed). Furthermore, the deflection (loop) of the paper in the registration area is controlled to ensure accurate image alignment.

T-11 is responsible for control around the photoreceptor, charging, transfer, separation,
Controls static elimination, high voltage '11 source for corona generation, and static elimination lamp. Furthermore, as the number of copies increases, toner, paper dust, etc. adhere to the tungsten wire of the charger for high pressure generation, and the toner melts and clings to the surface, causing uneven corona discharge. In order to prevent this, a ceramic vibrating element is brought into contact with the tungsten wire of the charging corona, and is vibrated during the copy sequence each time the copy is completed? Perform Sf cleaning.

T I 2 VJ, *Monitory that controls the exposure lamp, halogen lamp for exposure OON.

OFF is performed according to the timing. In addition, to avoid being affected by voltage fluctuations, the power supply voltage is digitally detected by an IID converter, converted to an effective value, and phase control is performed digitally. This task involves sampling the AC power supply and determining the phase angle.
is performing the calculation.

In T-13, the paper size is automatically detected by the paper conveyance path device, and the photoreceptor is erased according to the paper size.

T-14 controls the static elimination corona, static elimination lamp, and cleaner (blade) while sampling the surface potential using a surface potential sensor.

T-1s is a paper discharge control, which discharges paper, arranges copies on a stocker (paper discharge table), and increments a copy number counter by +1.

At T-t6, the heater temperature is controlled as follows. When the power source is turned on, the power is quickly controlled to keep the temperature at a predetermined level after startup, and during standby, the temperature is controlled below a predetermined temperature for the purpose of saving energy. 200°C during run, 150°C during standby). In order to control the power digitally, use the MPU's interval timer (\INTIM on Macro T-26) to detect the zero cross point (\ZEILOC on Macro T-28) and set the purpose (heater temperature). Performs phase control according to the

T-17 detects toner concentration and, in the case of a two-component developer, keeps the ratio of carrier to toner constant. In the case of a one-component developer, only the remaining amount of toner is detected and replenishment is performed.

In the case of the embodiment to which the present invention is applied, a standard pattern is placed on one corner of the document table, its reflected image is created on the photosensitive drum, and the amount of adhered toner is detected by an optical sensor.
/D conversion is processed and calculated by M P- and U, and toner replenishment is performed. The detected amount is stored in memory, and the D/A converter controls the current sent to the light emitting diode according to the condition so as to cancel fluctuations due to the ambient conditions of the photosensor. Double feeding is detected by comparing the paper with a reference value.

T-19i1: The developing bias is controlled according to the density of the original pattern and ground potential detection. The 0T-20, which controls the applied bias potential according to the degree of use (degree of fatigue) of the photoreceptor, detects dark and bright areas of the photoreceptor surface potential using an electrostatic field chopper sensor. In particular, when a residual potential is detected, the bias is controlled in a module 18 to be described later to maintain a certain level of image quality.

Dimming (feedback to lamp regulator).

T-22 is an output control by a voice synthesizer that responds to the operator with voice depending on the state.

'r-23 stores the spectrum of a specific speaker and is used as a substitute function for a key counter.

In addition, in case of an emergency, the machine will stop when the operator says ``Tomare'', ``0 stop''.

This allows you to stop the machine without being near the machine, so it can be used as a safety operation.

T-24 is for diagnosing the machine, and in the case of a minor breakdown, it provides voice guidance and asks the user to perform maintenance. The process of the machine is controlled without paper conveyance, and the machine status is checked in a timely manner so that the best copy can be made.

T-25 controls the external parts and accessories of the copier. In this case, the automatic document feeder (A, D.

F), sorter, collator, 0CR1 fee counter, etc.
Performs control with the main unit. The power supply is A, l),
F, 0C1lt, the charge counter can be powered from the main unit, and the sorter and collator are low.

Medium speed machine (10~4002M (CARDSPE MINU)
For 'rE)), power is supplied from the main unit, and for high-speed machines, a separate power supply is provided.

At T-26, the interval timer used in the program routine is controlled.

In this case, Intel 8051 is used as the MPU. This chip manages two 16-bit timers.

In T-27, if the copy start key is not pressed within a predetermined time (1 to 2 minutes), the set number of sheets, variable magnification, specified cassette, etc. are reset to standard mode, and the heater temperature is set to standby mode.

At T-28, the time counting IC is controlled such as notifying the copying job time, storing the copying date and time, and printing DATE on copy paper. It also controls fixed-time monitoring during machine diagnosis.

/' Next, the organization of tasks will be described. As mentioned above, Table 5 shows an example of organization in which tasks are organized according to the events that occur, and tasks are switched according to the count value of the timing pulse generated by the encoder when entering the copy cycle. This will be explained using entry salt.

Hi 1￥S) side, ￥RECAC, ￥P Shin-made The organization of the tasks listed in T-machi Hongan is to macro call each task via the monitor, and when the execution of one task (￥-) is completed, it will be displayed on the monitor. be returned. Between one task and the monitor,
Progress through the tasks in each mode one by one. If an emergency event occurs due to an interrupt or the like while a task is being executed, and the process is returned to the monitor (before the task execution is complete) and the execution mode is shifted to a different mode, except for the abnormal processing mode, There are cases where the same task is called in the next mode to continue processing, and cases where the task being executed is interrupted and the execution of the next task is started. In the former case, when the heater reaches a predetermined temperature from the pre-heater startup check routine, the mode shifts to the standby routine, but the macro\FU
SCN continues to control temperatures. The latter performs static neutralization and cleaning of the photoconductor after copying is completed, and when the copy start key is turned on during the execution of the task \PCCLN, this process is immediately interrupted and the copy run routine is entered.

The relationship between the monitor and the task has been described above, but if you configure it as in this application, even if the machine or control object is different, if you make the task into a program module and make it into a macro, you can easily change the monitor's task schedule. You can add or change any number of mechanical operations just by tinkering. For example, if there are many modes, you can set CPMOD in Table 1 to a 2-byte area, or if you want to change the execution order,
Just change the position of the bit. If the mode is not needed, it is sufficient to set only that bit pattern to 0 and not set it to 1. MULFN in Table 2, ABNOM 1, A in Table 3
BNOM 2. The same is true for DIAGN in Table 4. If the number of events increases, you can expand the registers. Therefore, create an extra unused register (10 to several hundred bytes) in advance.
It is usually stored inside the monitor. The monitor may be implemented as firmware, and in the case of a system using a one-chip MPU, it may be masked and resided in an on-chip memory. In the case of a system in which a memory is placed externally, a part of the memory or a monitor can be masked into one memory chip, and the system can be configured by placing that chip in the system.

That is, by appropriately inserting it into a machine system as a solid-state monitor, the program structure can be modularized, and the number of man-hours required for program creation and debugging can be greatly reduced.

Next, an outline of a copying machine to which the present invention is applied will be explained based on FIG. A two-stage paper feeder (7) 22, 23 is provided on one side of the main body 210 of the copying machine, and a paper discharge tray 24 is provided on the other side.

Around the photosensitive drum 25, a corona charger 46,
Erase lamp 47, optical system 48, developing roller 9, transfer/separation charger 10. A cleaning device 11 and a front fatigue lamp 12 are arranged as shown in the figure. A contact glass 13 is provided on the top surface of the main body 21, and the original on this is illuminated by an exposure lamp 14, and a lens system 15
is guided through the optical system 8 to the optical system 8. Each paper feed force cella)
22 and 230 sheets are guided to registration rollers 18 by respective sheet feed rollers 16 and 17. Due to the operation of the transfer/separation charger 10, the paper to which the toner image on the photoreceptor drum 25 has been transferred is separated by a separation bell).
19 to the fixing roller 20, and is finally stored on the paper discharge tray 24.

Next, the hardware configuration will be explained with reference to diagram #c9.

The MPU 5 uses an 8051 based on Intel Corporation, and uses two external ROMs.

ROM, 32 is 2732 (4 bytes), ROM
, 33 is equipped with 2764 (8 pieces) as a diagnostic nonvolatile memory, and 2 is provided with a byte C-MO8 RAM 34 as a data segment for monitoring 0 and S. Therefore, when all these are implemented, code memory (ROM
> will be 16 bytes, and RAM will be 2 + 128 bytes.

The MPU S has an internal 4-byte ROM and a 128-byte RAM that can be used by the user.

A program with byte 0 and S resides in internal 4, and the program for machine control is stored in external ROM, 32, “
Uses ROM, 33.

As a 1.10 element, Intel's 8255 PP1 (
4 programmable peripherals (ink face) are used. PPi has three 8-pit ports, and input/output ports can be configured by specifying the mode. Further, 36.2 8-bit A/D converters are of the 4-channel successive approximation type, and are used for acquiring analog data, and can be accessed by the PP1335 with p port support.

Similarly, the speech synthesizer is accessed from the PPi 335 boat. The built-in speech ROM allows for 30-second announcements on its own, but by adding one speech ROM, it is possible to make 100-second announcements.

Similarly, access the clock IC for boats.

PP1335, issue a command via Siboto, and
Count the hours, minutes, and seconds and enter the date and time on the copy; count the operating time and idle time of the machine; and check the process conditions (initialization of the diphotoreceptor, cleaning time, corona potential, (bias potential) settings.

Also, 7 bits out of the 8 bits of the input port of the PP1335 are wire-FOR'ed (37) and input to the external side input INT of the MPU 5. This person's capo is recognized by an interrupt, and by polling which line receives the signal, it is possible to perform bit shifting and prioritize. Therefore, it becomes possible to weight the signals. The main part of this priority setting is explained in 10-
It is shown in Figure 1 and Figure 10-2. The signal input to baud) A is sequentially shifted to the LSB side, that is, shifted to the right, as shown in FIG. 10-2, and tested for carry. Therefore,
bo has the highest priority. Therefore,
1)o-+l), weighting can be performed by selecting and arranging signals according to their importance.

Furthermore, using the serial input/output of MPU5 and UART,
Data communication with the outside world is possible.

If the system is incomplete with only the elements shown in FIG. 9, the pass line of the MPU 5 can be extended to the outside using a bus transducer 7 bar.

In addition, the D/A converter 39 has 8 bits and 2 channels and converts analog data acquisition to A/D.
The converter converts the power, the MPU 5 processes it digitally, and it is used for analog feedback. It is used for paper double feed detection, LED analog control, bias, high voltage power supply analog signal source (output proportional to analog signal), and servo motor rotation control signal.

As mentioned earlier, MPU5 is a single-chip MCU
(Microcomputer Units), CPU.

A computer (ROM, RAM, Ilo, counter, etc., all integrated into one chip) 8051 is used, and a zero cross pulse (ZCP) generated by a commercial power source is input to the interrupt line INTo. and timing pulse (50
It was used to count 10 seconds at Hz and 8.3 seconds at 60Hz! ! 11. When performing AC power control, phase control, and pulse width control using a program, when zCP is input, an internal counter is started and D/A conversion is performed.

Counter input T. , T, counts external pulses on the nodes regardless of program execution. Therefore, program execution efficiency is improved.

Interrupt INT is used for input port recognition of the line input to PPi 335 as described above.

The system reset 42 initializes the system immediately after the power is turned on, by sending a predetermined delay pulse to M
Input to the reset terminal of PU5.

FIG. 11 is a diagram showing a memory map, showing examples of a case (a) in which a monitor is stored in the memory on the MPU and (b) a case in which the monitor is stored in an external memory.

The monitor is the shaded area in the figure, and the internal memory is 4 bytes (0OOOH to 0FFFI(), and the monitor area is 2
Byte (QfQNIQfH - 47FFH). Also, if the monitor is stored in external memory (b), I
This is an example in which the monitor is stored in byte 2 of MBQfH~17FF)I.

FIG. 12 is a block diagram showing the state of connection with peripheral devices such as a sorter, collator, ADF, and charge counter.

In addition, if standard controllers are prepared for system tJ, small-scale systems (Figure 13), medium-scale systems, and large-scale systems and can be used in selected locations, software productivity can be increased. , the cost advantage is great. This is because the software has a built-in framework called a monitor, so all you have to do is install the necessary application programs into the machine.

In the embodiment of the present application, for example, the system example shown in FIG.
Multiple signals from one point on the photoreceptor drum (P, C, D) 25 are used as a start pulse. When a copy (several dozen copies) is finished, a start pulse is provided so that the image is not placed on the seam or the winding position, so that a new segment is automatically wound and a new segment is used. In the case of a seamless photoconductor, such a start pulse is not necessary (because it is seamless, it is okay to create an image from ζ), but when a servo motor is used for scanning the optical system,
In order to correct rotational fluctuations caused by power fluctuations, the accurate time required for one revolution of the drum is measured, and when scanning irregularities in rotation, this is calculated and processed as a correction value for the rotation control of the servo motor, allowing for proper image formation. The %MPU5 has rung control, heater control, display,
display scan, interface, keyboard switch,
Connected to the input/output hoard.

Figure 14 shows the hardware configuration and MPU shown in Figure 9.
Configuration of MPU 243 that connects 43 MI (MI) U2 by 5 VART and controls the optical system's servo motor controller (), the pulse motor control that sets the variable magnification value of the lens, and the display, voice recognition, and key human power section. FIG.

The MPU 243 further includes a voice recognition device.

Jinre is an optional feature that serves as a substitute for a key counter for a specific speaker.

The voiceprint of a specific speaker is memorized, and the input voice is spectrum-analyzed and compared with the voiceprint in memory. If the voiceprint matches, the input of a copy command is permitted. In addition, special voices (for example, stop, /stop,
You can prepare for unexpected situations by allowing copy stop, power off, dangerous, /) input. As this speech recognition device, a three-chip structure manufactured by NEC Corporation is used as an example. MC-4760 (analog I/F processor), μ
PD-7716 (speech recognition processor), μpl)-7
762 (controller). As will be described later, a microphone 118 for voice input is placed in the operation section. Although not shown, the copying machine may be equipped with a human body detection sensor to provide a human-machine interface (voice recognition, response) using voice when a person is detected.

FIG. 15 is a diagram showing the display operation section of the copying machine. In the figure, 101 is a jam indicator lamp, 102 is a toner empty indicator lamp, 23 is a cassette paper empty indicator lamp, 104 is a serviceman call lamp, 105 is a cartridge replacement lamp for photoconductor, etc., and 106 is a speaker of a voice synthesizer. ,
107 is an image density selection key, and 108 is a variable magnification mode selection key, which also performs display. 109 is a numeric keypad, 110 is a display for the number of sheets, etc., and 111 is an interrupt copy mode selection key for displaying information. 112 indicates whether access is possible, 113 is a voice guide key, 114 is a copy stop key, 115
116 is the number of copies set, 116 is a power switch, 117 is a cancel key, and 118 is an optional microphone for voice recognition.

When another copy is urgently required during continuous copying, the interrupt key 111 temporarily saves the data currently being copied (for example, the number of copies set, number of copies, copy magnification value, image density) etc. Remember it. Then, the interrupt is copied, and after the copying is completed, the data is automatically restored and the copying continues. The display 110 displays the set amount, such as the number of copies, using a segment LED or LCD, for example.

Although the display 110 displays only two digits and the number of sets is 0 to 99, it allows endless copying. Until the copy stop key 114 is turned on, copying can be continued until the paper runs out.

In addition, for low-speed machines, the upper limit for displaying the number of sheets, for example, 20 sheets, is inputted, and above that, for example, 7 SegL.
It is also easy to use by displaying FF on the ED to enable multi-copying. This upper limit value may be 2 or 10 sheets depending on the machine specifications.
It may be 01, 30, or 50. Since there are two segments, there is no need to allow input of up to 99 images, and it is sufficient to decide based on operability. Furthermore, the performance of recent popular copying models has improved, and the number of copies per unit time is now 15 to 2 compared to the conventional model.
From 0 sheets to 30-40 sheets, even 135 sheets are now available, making it possible to make a large amount of copies in a short period of time. 25 pieces of paper of the same size each in the upper and lower two cassettes.
If you insert 0 sheets one by one and make 500 copies, for example, if you set it so that when the upper cassette runs out of paper, the paper is automatically fed from the lower cassette, you can make 500 copies in a short time. With such endless copying, if you turn on the voice guide key, you will be notified by voice of the total number of copies to be made. It is also possible to notify the copy job time before or after copying. (For example, it will take 13 minutes.)
"It took 3 minutes.", etc.) When the voice guide key 113 is turned on, it notifies the user of the status of the copying machine by voice. For example, if you turn it ON during copying, it will say "Copy set number XX sheets, copy number XX sheets, remaining 00 sheets. It will take 00 seconds." There is a paper jam.

1 or ``There is a paper jam in the paper output section.'' Furthermore, if the supply is low, it will notify you of things like ``There is no paper in the upper cassette.'', ``Toner is low. Please replenish.'', ``Please replace the cartridge.'' . Copying machines equipped with a paper remaining amount detection mechanism will compare the number of sheets in the copy set and notify you that ``There is not enough paper left. Only 00 copies can be made.''

Also, when a failure is displayed, for example, if there is a jam in the transfer section,
"Please open the front cover.", "Next, pull out the transfer charger.", "Next, remove the jammed paper.", "Now you can remove the paper. All you need to do is cover the front cover." Please close and restart.'' Furthermore, if the user is unable to perform maintenance, the service man call 25 lamp will light up and the telephone number of the service station will be announced.

The image density selection key 107 is used to set the light of the exposure lamp, and when the key is shifted toward bright display, the light becomes brighter, and when the -\ key is shifted toward dark display, the light becomes darker. In this way, the brightness can be controlled manually.

As described above, the present invention manages each program moduleized task using a monitor for controlling the copying machine. The monitor of the present application tests for an abnormal value called a header, and if a serious abnormality occurs, it immediately takes action. Copy mode switching is also tested by the occurrence of an event. And Ilo glue location, there is also a buffer here! l), it is possible to test the input/output status of Ilo.

Then there is the timing pulse count controller,
Here, the timing pulses generated by the encoder are counted and the switching of the temporary task is performed. Similarly, it also controls the count of zero-crossing pulses, and manages a timer configured by counting zero-crossing triggers and zero-crossing pulses. There is also a task schedule controller, which switches each copy mode and configures and organizes the tasks to be executed accordingly.

Additionally, this controller can also test diagnostic status. It also organizes tasks for processing when abnormal values are detected through diagnosis.

FIG. 16 shows the functions of a copying machine managed and operated by an MPU and a monitor. In FIG. 16, ROM is a program memory, RAM is a data memory, and N-RAM is a program memory.
is a non-volatile data memory, ADC is an A/D converter, D
AC is a D/A converter, 10 is an I10 board, and a communication interface is an interface between an external device and the MPU system.

As mentioned above, by using the monitor proposed in this application, it is possible to design programs each time a machine is developed.
Instead of debugging, all you have to do is select the necessary program from the library, deploy it, and configure the task schedule. This can be easily accomplished by preparing a dedicated macro instruction. As a result, the program development period can be greatly reduced, and the efficiency and reliability of the software can be improved. FIG. 17 shows a general flowchart showing the functions of the monitor.

5TEP-101: Turn on the power and start from 5TEP-101. Here, a test is performed to initialize the data memory, Ilo. Determine whether RAM has already been initialized (power ON)
(If you have done it once, you don't need to do it again) STEP-102: Clear RAM. This is done by accessing a predetermined location in the mapped memory.

5TEP-103: Test whether or not the same mK Ilo has already been initialized. You only need to clear the RAM (same as 5TEP-102) once at 08:00. The RAM clear is the same, but when the CPU goes out of control due to noise etc., if these initial settings (initialization) are necessary through the diagnostic program, use 5TEP-102, except when the power is on.
5TEP-104 is executed.

5TEP (04: Set the absolute address of Ilo. This determines the input/output port and address of the I10 element.

5TEP405: Perform batch processing of Ilo. As a result of program processing in each task, the output of data on the sofa and external information are input through the input boat and stored in the input buffer. Therefore, input/output to the outside is based on the execution results of each task. Badge processing is performed all at once in this step.Therefore, the execution results of processing tasks may be slightly delayed depending on the speed of the MPU used.

In cases where even the slightest delay is not acceptable and extremely high precision control is required (for example, registration alignment of high-speed copying machines, servo control of optical systems, etc.), input/output may be performed by interrupting. If a zero cross trigger is required, an interrupt processing program shown in FIG. 4-4 is installed in the monitor, tests this flag, and performs a trigger.

5TEP-106: Test the registers shown in FIG. 6 and schedule tasks. The outline of this is shown in Figure 7 in the flow chart. or,
Tables 1 to 3 explain the contents of status. Task scheduling is tested by giving priority to abnormality processing tasks and copy processes in progress.

S'I'EP-107: Perform abnormal mode test.

5TEP-108° Test the mode during copy process execution.

5TEP-109: Perform initial check mode test.

5TEP-110: Perform warm-up mode test.

5TEP-111: Perform a standby test in a copyable state.

5TEP'-112: Perform a test during the processing process after copying is completed.

5TEP-113: The execution of this processing task is entered when it is not scheduled in any stage, and it may have gone out of control due to noise or the like, so it should be diagnosed. As a result of the diagnosis, perform abnormality handling tasks or
System again.

After initialization, the same process as when the power is turned on is performed from the beginning.

5TEP-114: Jump to the abnormality processing stage ○ Test whether the task organization has already been completed, and if the organization has already been completed, 5TEP-1
Jump to 16.

5TEP-115: Organize the abnormality processing task. The contents of the organization are as shown in the explanation section of the organization example (■) above.

5TEP-116: Task scheduling is performed here. That is, each subdivided task is returned to the monitor after one task is executed, and the next task is sequentially executed. Some of them do not need to be executed once the process is completed, unless a new event occurs. The execution order of such individual tasks is controlled by registers.

5TEP-117: Performs a macro call for a processing task according to the scheduling of 5TEP-11 and 6. Then, move away from the monitor and execute the task. The structure is such that the screen returns to the monitor at the end of each subdivided task. The monitor may be called to re-enter the monitor, or the monitor may be made aware of the end of execution by an interrupt (software interrupt).

5TEP-118: Copy process execution processing in progress.

Test whether the task has already been organized.

5TFI: Organize P-119+ tasks. The contents of the organization were shown in the explanation section of the organization example ① above.

5TEIP-120° process is running and task switching depends on encoder pulse count. Test the current value by testing the pulse count value input to the event counter or interrupt.

Tasks are scheduled according to the values of the 5TEP-12C encoder pulses. Tasks that are not related to the encoder pulse count value, such as display, input key entry, and clock counting, are executed sequentially and alternately regardless of the value.

5TEP-122: Make a macro call for the task.

Please refer to Figure 17-b.

5TEP-123: In the same way, initial check tasks are organized according to the contents of Pn126 55, ■ and are executed sequentially based on scheduling.

It was shown in

5TEP-131: Organize the tasks of the standby routine.

? 134 The contents of the composition are shown in the explanation section of the composition example ■ above.

5TEP-135: Tasks for the process at the end of copying? 139. At this stage, the photoconductor drum and other mechanical parts are being cleaned and positioned in preparation for the next copy operation, and in some cases, the copy process may still be in progress (e.g., paper ejection, scanner return). Because there is, it depends on the encoder pulse count value. Also, if there is no problem with the next copy operation, a copy enable signal is issued.

Effects As explained above, the present invention uses a monitor to organize tasks each time an event occurs, and executes each subdivided task sequentially by calling a macro. By preparing a menu of standardized program modules, it is possible to add new functions at will, which has the effect of greatly improving the productivity of programs and hardware.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of the monitor. Figure 2 UMPU,! : Diagram showing the relationship between encoder and zero-cross pulse. FIG. 3 is a diagram showing the relationship between timing pulse counting and comparison verification. FIG. 4-1 is a diagram showing the generation of Hzcp in an alternating current AC. Figure 4-2 is a partially enlarged view of Figure 4-1. FIG. 4-3 is a diagram showing the structure of a flag register for zero-cross pulse control. Figure M4-4 is a zero-cross pulse control flowchart. FIG. 5 is a flowchart of the copying process. FIG. 6 is a diagram showing the status checked on the monitor. FIG. 7 is a flowchart of task schedule control. FIG. 8 is a diagram showing an outline of a copying machine which is an embodiment of the present invention. FIG. 9 is a diagram showing the hardware configuration. FIG. 10-1 is a diagram showing an interrupter fan-out. FIG. 10-2 is a diagram showing a test of interrupt input. FIG. 11 is a diagram showing a memory map. FIG. 12 is a diagram showing the state of connection with peripheral devices. FIG. 13 is a diagram showing an example of a system configuration. Figure 14 shows MP connected by VART of MPU5.
The figure which shows the structure of U243. FIG. 15 is a diagram showing the display and operation section of the copying machine. FIG. 16 is a diagram showing the functions of the copying machine managed by the MPU and the monitor. Figures 17-a and 17-b are general flowcharts showing the functions of the monitor. 1 is a monitor, 2 is a header, 8 is a task schedule control, 5 is an MPU, and 43 is an MPU. Patent Applicant: Canon Co., Ltd. 11.1.110(a)(b)

Claims (5)

[Claims] (1) A monitor means for managing programs, a task scheduler means for organizing program modules for each task so that a predetermined task group can be executed according to the occurrence of an event, and a task group organized by the task scheduler means. An image forming apparatus characterized by having means for performing the following. (2) The image forming apparatus according to claim 1, further comprising means for reducing the length of the organized program and making it common according to the object to be controlled. (3) The event is generated by counting timing pulses emitted by an encoder driven by a motor and reaching a predetermined fat set in advance. The image forming apparatus according to item 1. (4) The monitoring means is characterized by comprising a header for detecting the occurrence of an abnormality and the occurrence of an event, a means for counting timing pulses, a means for controlling zero-crossing pulses, and a means for controlling the schedule of tasks. An image forming apparatus according to claim 1. (5) The image forming apparatus according to claim 1, wherein switching of tasks during an image forming cycle is performed by a timing pulse count included in a monitor means.