JPH06102720A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an image forming device suppressing dispersion in a response time caused by a change in a clutch state and simultaneously, having excel lent image formation. CONSTITUTION:When a power source is turned on and a main motor M1 obtains prescribed rotational speed, the clutch CL1 driving a pair of clutch timing rollers 15 is turned on. Time until the rotational speed of a pair of the timing rollers 15 reaches prescribed one after the clutch CL1 is turned on is counted and when the value beta of the count is smaller than a prescribed value alpha set in advance, the value of a clutch timer is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art An image forming apparatus is provided with a clutch for transmitting a driving force generated by a driving source such as a motor to driving units such as an image forming unit and a sheet conveying system. The operation operation of this clutch is controlled by the control circuit, and its response time due to wear, that is, the time from the generation of the operation signal to the actual transmission of the driving force to the driven portion becomes long. Conventionally, the clutch having such a long response time has been replaced.

[0003]

However, the response time of the clutch gradually changes due to wear.
Therefore, exchanging the clutch when the response time slightly changes results in wasteful cost and man-hours because the clutch is not used effectively. On the other hand, a clutch whose response time is greatly changed adversely affects image formation.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus which corrects the variation of the response time due to the change of the state of the clutch and can form an image well.

[0005]

In order to solve the above-mentioned problems, the present invention provides a driving source for generating a driving force for driving a driven part, and a driving force from the driving source to the driven part. A clutch that selectively transmits, a signal generating unit that outputs an operation signal for operating the clutch, and a response time from when the operation signal is generated to when the driving force is transmitted to the driven portion. And a changing means for changing the generation timing of the operation signal by the signal generating means based on the response time measured by the measuring means.

[0006]

In the above structure, the driving source generates the driving force for driving the driven portion. The clutch selectively transmits the driving force of this driving source to the driven part. The signal generating means outputs an actuation signal for actuating the clutch. The measuring means measures the response time from the generation of this actuation signal to the transmission of the driving force to the driven part. Based on the response time measured by the measuring means, the changing means changes the generation timing of the operation signal by the signal generating means.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the schematic arrangement of the copying machine of this embodiment. The copying machine 1 includes a scanning optical system 21, an image forming unit 22, and a transport system 23. The scanning optical system 21 exposes and scans a document placed on the platen glass 2. The scanning optical system 21 has a switch SW1 which is turned on when the scanner 5 passes a predetermined position. The image forming unit 22 forms an image from the reflected light image exposed and scanned by the scanning optical system 21. The image forming unit 22 has a photosensitive drum 6 rotatably supported in a direction in the drawing as a center, and a charging charger 7, a developing device 8, a transfer / separation charger 9, and the like around the photosensitive drum 6.
A cleaning device 10 and an eraser lamp 11 are provided. The transport system 23 transports the transfer paper stored in the paper feed cassette 12 to the image forming unit 22.
The transport rollers 13a, 13b, 13c and the timing roller pair 15 are provided. The transport system 23 also includes a transport belt 16 that transports the transfer sheet on which the image is transferred in the image forming unit 22 to the fixing unit 17. Further, the transport system 23 has a discharge roller pair 19 for discharging the transfer paper, on which the image is fixed by the fixing unit 17, from the copying machine 1. A main switch 3 for turning on the power is provided on the side of this copying machine.

The copying machine 1 includes an image forming section 22 and a conveying system 2.
A main motor M1 for driving a driving unit such as 3 is provided. Clutches CL1 to CL6 are provided for transmitting the power of the main motor M1 to the image forming unit 22 and the transport system 23. The clutch CL1 transmits power to the timing roller pair 15. The clutch CL2 transmits power to the pair of transport rollers 13a, 13b, 13c provided on the transport path from the paper feed cassette 12 to the pair of timing rollers 15. The clutch CL3 is a paper feed roller 14 that guides the transfer paper stored in the paper feed cassette 12 to the conveyance path.
Transmit power to. The clutch CL4 transmits power to the photoconductor drum 6 and the cleaning device 10. Clutch C
L5 transmits power to the developing device 8. The clutch CL6 transmits power to the conveyor belt 16 that conveys the transfer sheet onto which the toner image has been transferred to the fixing unit 17. The on / off control of the main motor M1 and the clutches CL1 to CL6 is performed by a microcomputer.

In the above structure, the original placed on the original table glass 2 is scanned by the scanning optical system 21 and projected onto the photosensitive drum 6 charged by the charging charger 7. An electrostatic latent image is formed by this projection. This electrostatic latent image is developed by the developing device 8 to be a toner image. This toner image is transferred from the timing roller pair 15 onto the transfer paper sent at a predetermined timing, and is fixed by the fixing unit 17 having the fixing roller pair 18. The transfer paper on which the toner image is fixed is discharged from the copying machine main body 1 by the discharge roller pair 19.

In the following description, the timing roller pair 15 is used.
The operation control of the clutch CL1 will be described below.
Similar operation control is executed for the other clutches CL2 to CL6.

FIG. 2 is a diagram showing the peripheral structure of the timing roller pair 15 and the clutch CL1. Since the timing roller pair 15 aligns the leading edge of the image formed on the photosensitive drum 6 with the leading edge of the transfer sheet, the transfer sheet is temporarily stopped before the timing roller pair 15 and the leading edge of the image on the photosensitive drum 6 is reached. The conveyance of the transfer paper is restarted at the timing when the leading edge of the transfer paper coincides. A clutch CL1 is provided at one end of the timing roller pair 15 in the longitudinal direction,
By turning on the clutch CL1, the driving force of the main motor M1 is transmitted to the timing roller pair 15. An encoder plate 26 is provided at the other end of the timing roller pair 15 in the longitudinal direction. A photo sensor 27 is provided so as to sandwich the encoder plate 26, and the encoder plate 26 and the photo sensor 27 form an encoder 24 that generates a pulse signal in synchronization with the rotation of the timing roller pair 15.

FIG. 3 is a diagram showing a control configuration of the copying machine 1.

The copying machine 1 includes a microcomputer 1
It is controlled by 06. The microcomputer 106 includes a switch SW1, a photo sensor 27, a clutch CL1, a display unit 29, and a main motor control circuit 11
It is connected to 0. The photo sensor 27 is connected to the microcomputer 106 via the frequency-voltage converter 28. The main motor control circuit 110 includes a reference oscillation unit 100, a phase comparison unit 101, a frequency comparison unit 102, a synchronization detection / integration unit 103, a PWM control unit 104, and an FG.
The pulse generator 107 is provided. Main motor M1
Are controlled by the main motor control circuit 110 to rotate at a constant speed.

The FG pulse generator 107 is a main motor M.
A pulse signal is generated according to the rotation speed of 1. This FG
The pulse signal of the pulse generator 107 is input to the phase comparator 101 and the frequency comparator 102. Phase comparison unit 101
In, the phase of the pulse signal of the FG pulse generator 107 is compared with the phase of the pulse signal generated from the reference oscillator 100. On the other hand, in the frequency comparison unit 102, the pulse signal of the FG pulse generation unit 107 is frequency-compared with the pulse signal generated from the reference oscillation unit 100. Phase comparison unit 101
The signal output from the frequency comparison unit 102 is input to the synchronization detection / integration unit 103. The synchronization detection and integration unit 103 includes a phase comparison unit 101 and a frequency comparison unit 102.
The PLL lock signal is output to the microcomputer 106 by detecting the synchronization state of the signal output from the. Further, the synchronization detection and integration unit 103 integrates the signals output from the phase comparison unit 101 and the frequency comparison unit 102, and outputs the integrated signal to the PWM control unit 104. The microcomputer 106 outputs a main motor drive signal for turning on / off the main motor M1 to the PWM control unit 104. PW
When the main motor drive signal output from the microcomputer 106 is on, the M control unit 104 determines the main motor M based on the signal from the synchronization detection and integration unit 103.
The voltage applied to 1 is pulse-width modulated. In this way
The PWM control unit 104 controls the electric power supplied to the main motor M1. Further, a current limiter circuit 105 is connected to the PWM control unit 104 in order to prevent a current of a certain level or more from flowing through the main motor M1.

FIG. 4 is a diagram showing a main routine of control executed in the microcomputer.

When the power is turned on and the program is started, initialization is performed in step S1 and an internal timer for defining the time required for the main routine to rotate once is set in step S2. This internal timer is counted by the reference clock in the microcomputer 106. Then, in step S3, a copy operation processing subroutine is performed, and in step S4, a response time detection processing subroutine is performed. In step S5, a subroutine for performing other processing is executed, and when the processing of all the subroutines is completed, the process returns to step S2 after waiting for the internal timer to be completed in step S6.
While the power is on, step S2 to step S6
The process of is repeated.

FIG. 5 is a flowchart of the copy operation processing subroutine (step S3).

First, in step S301, it is determined whether or not the copying operation has started. If the copying operation has started, the process proceeds to step S310, and if not started, the process returns to the main routine. The clutch CL1 is turned on in step S310, and other copying operations are controlled in step S320.

FIG. 6 is a flowchart of the on control of the clutch CL1 in step S310.

First, in step S311, the on-edge of the switch SW1 provided in the scanning optical system 21 is detected. Here, the "on edge" refers to a state change in which the signal from each sensor or switch changes from off to on. The switch SW1 is turned on when the scanner 5 reaches a predetermined position due to the movement of the scanner 5. If the switch SW1 is on-edge in step S311, the clutch timer Tcl is started in step S312, and the flag F4 necessary for turning on the clutch CL1 is set to 1 in step S313. The clutch timer Tcl defines the time from when the switch SW1 is turned on to when the clutch CL1 is turned on. On the other hand, if the switch SW1 is not on edge in step S311, step S3
Jump to 14. In step S314, it is determined whether the flag F4 is 1, and if the flag F4 is 1, it is determined in step S315 whether the clutch timer Tcl has expired. If the clutch timer Tcl has expired in step S315, the clutch CL1 is turned on in step S316, and the flag F4 is set to 0 in step S317. On the other hand, if the flag F4 is 0 in step S314, the process returns to the main routine. If the clutch timer Tcl has not expired in step S315, the clutch timer Tcl is counted up in step S318 and then the process returns to the main routine.

FIG. 7 is a flow chart of the response time detection processing subroutine (step S4).

First, in step S401, it is determined whether or not the copying machine 1 has just been powered on. Step S
In 401, if the power is just turned on, step S40
2, the main motor M1 is turned on, and step S40
In 3, the flag F1 is set to 1. In step S404, it is determined whether the flag F1 is 1. Step S40
If the flag F1 is 1 in step 4, step S405
At, it is determined whether or not the main motor M1 has reached a predetermined rotation speed, based on the PLL lock signal generated from the main motor M1. If the main motor M1 has reached the predetermined rotation speed in step S405,
The flag F2 is set to 1 in step S406, and the flag F1 is set to 0 in step S407. This flag F2 is a flag necessary for turning on the clutch CL1 and starting the response time measurement counter. On the other hand, if the flag F1 is 0 in step S404, and
If the main motor M1 has not reached the predetermined rotation speed in step S405, the process skips to step S408. In step S408, it is determined whether the flag F2 is 1. If the flag F2 is 1 in step S408, the clutch CL1 is turned on in step S409, that is, an on signal is output to the clutch CL1.
In step S410, the response time measurement counter is started. This response time measurement counter is the clutch CL
Timing roller pair 15 after the ON signal is output to 1
Is for measuring the time required to reach a predetermined rotation speed. Then, the flag F3 is set to 1 in step S411, and the flag F2 is set to 0 in step S412. On the other hand, if the flag F2 is 0 in step S408, the process skips to step S413. In step S413, it is determined whether the flag F3 is 1. If the flag F3 is 1 in step S413, the timing roller pair 15 is set in step S414.
Determines whether the rotation speed has reached a predetermined rotation speed. on the other hand,
If the flag F3 is 0 in step S413, the process returns to the main routine. If the timing roller pair 15 has reached the predetermined rotation speed in step S414, the response time measurement counter is stopped in step S415, and whether the count value β measured by the response time measurement counter in step S416 is larger than the predetermined value α or not. To judge. The predetermined value α is a preset threshold value for the microcomputer 106 to determine whether the clutch CL1 can be used or not. On the other hand, if the timing roller pair 15 has not reached the predetermined rotation speed in step S414, the response time measuring counter is counted up in step S419 and then the process returns to the main routine. If the count value β is larger than the predetermined value α in step S416, the microcomputer 106 determines in step S417 that the clutch CL1 cannot be used, and displays on the display unit 29 on the operation panel prompting replacement of the clutch. I do. On the other hand, if the count value β is smaller than the predetermined value α in step S416, step S42.
The routine proceeds to 0 to enter a subroutine for changing the value of the clutch timer Tcl. Finally, in step S418, the response time measurement counter is initialized and the flag F3 is set to 0.

FIG. 8 is a flowchart of a subroutine for performing the process of changing the clutch timer Tcl in step S420.

Since the clutch CL1 wears as the number of times of use increases, it takes a long time from when the microcomputer 106 outputs an ON signal to the clutch CL1 until the timing roller pair 15 reaches a predetermined rotation speed.
Therefore, since the count value β also gradually increases as the number of times of use of the clutch CL1 increases, the value of the clutch timer Tcl is changed to correct the response time of the clutch CL1.

First, in step S421, the correction value s is obtained by taking the difference between the count value β and the preset reference count value r. In step S422,
In order to accelerate the on-timing of the clutch CL1 by the correction value s, the value of the clutch timer Tcl is set by taking the difference between the reference value R of the timer and the correction value s.

As described above, when the clutch CL1 slips due to wear of the clutch CL1 and the response time of the clutch becomes long, the response time of the clutch CL1 is delayed by setting the value of the clutch timer Tcl to a small value. Can be supplemented.

In the embodiment described above, the clutch timer Tcl is started by the switch SW1 provided in the scanning optical system.
The start of cl may be performed by other switch means.
Further, although the response time of the clutch CL1 is detected immediately after the power of the copying machine 1 is turned on in the present embodiment, it may be detected every copying operation.

[0029]

As described above, according to the present invention, the changing means changes the generation timing of the clutch actuation signal based on the response time measured by the measuring means, so that the variation of the response time due to the change of the clutch state is corrected. Along with
A good image can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a copying machine in this embodiment.

FIG. 2 is a diagram showing a schematic configuration of a timing roller pair in this embodiment.

FIG. 3 is a diagram showing a control configuration of a main motor in the present embodiment.

FIG. 4 is a diagram showing a main routine of the present embodiment.

FIG. 5 is a flowchart of a response time detection processing subroutine.

FIG. 6 is a flowchart of a subroutine for performing processing for changing a clutch timer.

FIG. 7 is a flowchart of a copy operation processing subroutine.

FIG. 8 is a flowchart of clutch on control.

[Explanation of symbols]

 15 Timing roller pair 21 Scanning optical system 22 Image forming unit 23 Conveying system 24 Encoder 27 Photo sensor M1 Main motor CL1-CL6 Clutch

Claims (1)

[Claims] 1. A drive source for generating a driving force for driving a driven part, a clutch for selectively transmitting the driving force from the drive source to the driven part, and a clutch for operating the clutch. A signal generating unit that outputs an actuation signal, a measuring unit that measures a response time from when the actuation signal is generated until the driving force is transmitted to the driven unit, and a response time measured by the measuring unit. An image forming apparatus comprising: a changing unit that changes the generation timing of the operation signal by the signal generating unit based on the above.