JPS58208757A - Electronic copying device - Google Patents

Abstract

PURPOSE:To keep the quantity of charge/exposure at its optimum status, by providing a displaying means for displaying the number of revolutions detected by a detecting means for detecting the number of revolutions related to a recording drum. CONSTITUTION:Notches are formed on the whole peripheral edge of a pulse disc 62 coaxially fixed on a rotary shaft of a photosensitive drum and a photointerruptor 63 is arranged in a noncontact state so as to clip the pulse disc 62. When the pulse disc 62 is rotated integrally with the rotation of the photosensitive drum, the peripheral notches pass through the gap part of the photointerruptor 63, so that a phototransistor built in the photointerruptor is turned on and off repeatedly and generates square waves and the number of revolutions of the photosensitive drum can be detected by using said procedure. Consequently, the number of revolutions is controlled so that the quantity of charge/exposure is kept at its optimum status.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic copying machine equipped with a self-diagnosis function that detects and displays the rotational speed of an electronic copying machine.

A conventional electronic copying apparatus generally has a configuration as shown in FIG. Here, the photosensitive drum rotatably supported by the apparatus main body is rotated in the direction of the arrow by a drive system (see FIG. 2), which will be described later. On the outer peripheral surface of the photosensitive drum λ, a seventh-order charger 3, an exposure simultaneous charger Hiroshi, a full-surface exposure light source j1, a developer B, a transfer charger 7, and a cleaning device g are arranged in this order.

The optical system for reading the original image includes, in order, the original exposure light source 9, the first moving mirror /θ, the first moving mirror /θ, the lens /2, the third fixed mirror l3, and the qth fixed mirror /l.
It consists of l. The first moving mirror lθ and the second moving mirror // reciprocate in the horizontal direction at a speed ratio of /:2. The above-mentioned optical system slit-exposes the image of the document placed on the document stacking table/3 on the upper surface of the apparatus main body/onto the photosensitive drum λ. Also, the main unit of the device has a paper cassette/
6 is attached and detached freely. Paper/g is sent out from this paper feeding cassette/l by a paper feeding roller 17. Furthermore, paper/g is roller pair/? 1 and /92 toward the photosensitive drum λ in synchronization with the toner image on the photosensitive drum λ, and comes into close contact with the photosensitive drum λ at the position of the transfer charger 7, after which the toner image is transferred from the photosensitive drum λ. , is separated from the photosensitive drum and sent to a roller pair and a fixing section via a conveying device. Next, the transferred toner image is fixed on the paper /g as it passes between the image roller 2 / and a pair of paper ejection rollers 23 . and 232 and is discharged to the paper discharge tray 21.

FIG. 2 shows an example of a drive system of the conventional device shown in FIG. 1, in which a gear 3/ is attached to the output shaft of a motor 3θ. A pin 33 is implanted on the eccentric side of a large-diameter gear 32 that meshes with the gear 3/, and the photosensitive drum 2 is rotated via the pin 33. Further, another gear 3II meshes with the above-mentioned gear 3/. The driving force of the motor 30 is transmitted to the timing belt 36 via a timing pulley 3S installed coaxially with the rotating shaft of the gear 3g. The rotation of the timing boot 1JJ7 transmitted via the timing belt 36 is transmitted to the drive transmission mechanism 3.
It is transmitted to the wire pulley tis via g. The illumination lamp and the optical scanning mirrors /θ and // are reciprocated through the wire winding around the wire pulley 13 which rotates in two directions in forward and reverse directions by the on/off operation of the clutch means 41/. Furthermore,
Another gear is meshed with the large diameter gear 32 described above.

A timing bell Jθ is wound around a timing pulley coaxially attached to the rotating shaft 9 of the gear 4I7, and the driving force of the motor 30 is transmitted to the timing pulleys 3 and J through the bell) 5θ. Timing pulley S/
An electromagnetic clutch j3 is attached to the. When the electromagnetic clutch j3 is turned on, the timing pulley! The rotation of ;/ is transmitted to the shaft jII, and further to the timing pulley JJ
, timing belt St and timing pulley j7
through the paper feed roller/71. and /72, and its roller /7. The rotation of 172 sends the paper/g from the paper feed cassette lt to the drum λ. On the other hand, the timing pulley! , 2, a gear 59 is attached to the shaft 51r. Gear O is meshed with this gear 39, and an electromagnetic clutch O is attached to gear O. When the electromagnetic clutch 61 is turned on, the register rollers 9 and /92 connected coaxially with the gear 10 rotate, and the transfer paper /g is conveyed to the photosensitive drum λ in synchronization with the image.

Here, the exposure amount of the document exposure light source 9 shown in FIG. 1 is almost constant without any change. On the other hand, the photosensitive drum 2 is rotated by the drive motor 30, but since its drive system has the above-described structure, various loads are applied to the photosensitive drum 2, and the load may fluctuate.

This variation is particularly influenced by the cleaner. For example, the cleaner load changes due to the wear of the cleaner blade, and the cleaner pressure also changes due to the wear of the surface of the photosensitive drum. Moreover, over a long period of time, the load increases due to wear of the rotating bearing. Therefore, the number of rotations of the photosensitive drum λ can change depending on variations in the load. Further, even if the apparatus is the same, there are variations in the load depending on the machine, so naturally the 0 rotation speed of the photosensitive drum will differ depending on the apparatus. However, in an electronic copying apparatus, it is necessary to always keep the charging and the exposure amount in an optimal state. For example, if the rotation of the photosensitive drum is extremely slower than the optimum rotation, the amount of exposure will increase and the charging time will also become longer, resulting in a recorded image that is washed out. On the other hand, if the rotation of the photosensitive drum 2 is extremely faster than the optimum rotation, the amount of exposure will be reduced and the charging time will be shortened, resulting in a recorded image appearing blackish. However, in the conventional electronic copying apparatus, since it was not possible to accurately detect and display changes in the rotational speed of the photosensitive drum, there was a drawback that the relationship between charging and exposure amount could not be maintained optimally.

Unfortunately, as mentioned above, the recorded image may become whitish,
It was difficult to obtain good image quality due to dark spots.

It is an object of the present invention to eliminate the above-mentioned drawbacks, detect and display the rotational speed of the motor that drives the photosensitive drum, adjust the rotational speed of the motor to maintain the optimum amount of charge and light, and speed up the copying process. It is an object of the present invention to provide an electronic copying apparatus having a self-diagnosis function that can maintain a constant value.

Furthermore, the present invention uses the motor rotation speed detection and display means to detect changes in the load on the photosensitive drum, such as abnormalities in cleaners, bearings, etc., or to detect extreme changes in motor rotation speed, making it easy to discover abnormalities in the drive system. An object of the present invention is to provide an electronic copying device that can perform the following functions.

In particular, since the present invention has a self-diagnosis function using a monitor,
For example, by using an inverter motor that can change the rotation speed freely as the drive motor for the photosensitive drum, it is possible to confirm that the rotation speed of the motor has changed during regular maintenance work, and to change the rotation speed of the motor at that time. It is characterized by the fact that high-quality copied images can always be obtained at a constant copying process speed.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 3 and FIG. 1I show an example of the configuration of an inverter motor used in the electronic copying apparatus of the present invention. Here, there are rectangular wave PWM, sine wave approximation PWM, etc. as control methods for the inverter of the induction motor, but among them, sine wave approximation PWM is superior to other methods in terms of motor efficiency, vibration noise, etc. ,
Furthermore, with the recent increase in the integration density and price reduction of digital ICs, digital sine wave approximation PWMO is attracting attention as being more suitable than analog sine wave approximation PWM. First, a predetermined bit signal corresponding to the frequency at which the motor is to be driven is supplied to the signal line A. For example, when driving a motor at 10 Hz, an address signal corresponding to the frequency and a combination of a plurality of bits specifying the initial address of the one-domain memory ROM is supplied to the signal line A. This signal may be given by an LSI such as a microcomputer, or it may be fixedly given by something like a dip switch. Then, the rate multiplier RM, which receives a signal from the oscillator O8C which oscillates at a certain frequency, determines the read interval time of the read-only memory ROM according to the information of the above-mentioned address signal on the signal line A. , the decision information is converted into a binary counter BC
The binary counter Be outputs a read-only memo through one output terminal according to the output. Specify the J ROM addresses in sequence.

Along with the address designation, a designated read-only memo! J
Pattern data II corresponding to the designated frequency is read from the ROM address and supplied to one input terminal of the waveform synthesis circuit WS. On the other hand, binary counter BO
The output from another output terminal O is supplied to the decoder D, and according to the output, the output of the decoder D is sent to the waveform synthesis circuit WSO.
Supplied to another input terminal. A plurality of output signals read from the read-only memory ROM at appropriate fixed time intervals are sequentially selected in the waveform synthesis circuit WS by the output of the decoder D, and thereby the waveform synthesis circuit WS calculates the approximate sine of each phase of the induction motor. Create a wave signal. The approximate sine wave signal is further supplied to a signal splitter SD, and a signal splitter S
The output of D is applied via amplifier B to the penis terminal of motor drive transistors TR/-TI in FIG. q. Through these series of operations, the motor is driven at a frequency corresponding to signal A in FIG.

In Figure 1, AC is AC'ili source (commercial power supply), D
I is a diode rectifier for converting AC voltage into DC voltage, C is an electrolytic capacitor for rectification, TR/, TR2゜...TR6 is a power transistor that controls the current of the three-phase motor (IN) JO, D/, Du,...
...D6 are transistors TR/ and TR2, respectively.
,...TI protection diode, and LOAD
is the load of the three-phase motor IN.

FIG. 5 shows an example of the configuration of the drive system of the electronic copying apparatus of the present invention. Note that the same parts as in the conventional example shown in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

Here, 6- is a digit pulse disk (pulse encoder) t2 installed coaxially with the rotating shaft of the photosensitive drum.

Since the pulse disk 62 and the gear 32 are integrally connected via the rotating shaft, rotation of the photosensitive drum 62 is transmitted to the pulse disk 62 via the pin 33. On the outer peripheral edge of this pulse disk λ, cutouts are formed at equal intervals along the circumferential direction as shown in FIG. 6 over the entire circumference. 63 is a photo interrupter (photo coupler), and the pulse disk 6
Attach 2 so that they are sandwiched together and do not touch each other. Therefore, a photosensitive drum! When the pulse disk 63 rotates together with the rotation of the pulse disk 63, the notches formed on the outer periphery of the pulse disk 61 sequentially pass through the gaps of the photointerrupter 3. As the light passes through this notch, the phototransistor in the photointerrupter 63 shown in FIG. 7 is repeatedly turned on and off, generating a rectangular wave as shown in the figure as its output. This rectangular wave signal is used for control during normal copying operations.

Here, as shown in FIG.
If it is divided into 00 parts and notched, exactly 700 pulses CLK will be obtained for one rotation of the photosensitive drum. On the other hand, the main body has a built-in microcomputer CPU as shown in FIG.
Count the number of pulses CLK per second and display the display DI.
The counted number is displayed digitally on the SP. In this embodiment, by pressing a predetermined key on the numeric keypad 0KEY for setting the number of copies per copy, the self-diagnosis mode is entered, the pulse CLK is counted, and the pulse number is displayed on the DISP display for displaying the number of copies per copy. indicate. Also, based on the number of pulses, the built-in microcomputer (hereinafter referred to as microcomputer) CPU calculates the rotation speed in units of rpm, for example.
The operation of the apparatus shown in FIG. 9 will now be described in more detail with reference to the flowchart shown in FIG. 10.

First, when the operator presses a predetermined key on the numeric keypad CKEY to issue a self-diagnosis instruction, such as the "za" key, a human input signal from that key is supplied to the microcomputer CPU, and its internal switch is A self-diagnosis mode selector switch SW (not shown) is turned on (closed) to enter the self-diagnosis mode (steps S/and S2).

Based on this self-diagnosis mode, after clearing the contents of timer T (not shown) and pulse counter PCT (not shown) in the microcomputer CPU, timer T is activated (step S
3).

Furthermore, step SV sends a drive start signal from the microcomputer CPU to the motor control board (motor drive circuit) MTO.
), motor control base i MTC17 of motor 3θ
) Starts rotation according to the drive signal, and gears 3/ and 32
The photosensitive drum λ and the pulse disk O 2 integrated with the drum λ are rotated through the drum λ. This rotation of the pulse disk 62 causes the photointerrupter 63 to generate a pulse CLK (step S5).

The microcomputer CPU takes in the pulse OLK from the photointerrupter O3 (step S) and counts the pulse OLK using the above-mentioned pulse counter POT (step S7). Subsequently, the timer T is set for a predetermined time t1, for example, 2
Steps s and r to determine whether or not the time of seconds has elapsed.
), if the determination is negative, the reading and counting of the pulse OLK is continued (steps S6 and S7). Next, when the predetermined time t has elapsed, the motor 3θ is stopped, and the process moves to the next step, where the count number of pulse OLK is converted to the number of pulses per 7 seconds (step Sq), and the converted value is digitally displayed on the display DISP. Display (step S70)
). Next, after turning off the self-diagnosis mode changeover switch SW (step S/l and 572), the display DISP
Turn off the count display and turn off the light (Step 5)
73), the control branches from the self-diagnosis mode and enters the normal Fubee control work mode (steps Stl~S/B/B).
...). During regular maintenance, service personnel and operators perform the above self-diagnosis process (step S).
~ S/3) by executing the drum 20 revolutions (
If you notice that the rotation speed (rotation speed) has changed beyond the allowable value, you can change the set value of the rotation speed of the motor 30 via the 91J ditub switch DSW, etc., thereby increasing the copying process speed. It can be corrected to a constant value.

In other words, if you change the setting of dip switch DSW,
The value of the drive signal supplied to the signal line A in FIG. 3 changes, and the rotation speed of the motor 3θ can be reset.

In addition, in the above-mentioned steps Sq and SIO, the time per rotation of the drum may be converted and displayed, and the pulse count number may be converted into a speed value (v ctn / sec
) may of course be converted and displayed. Further, instead of the rotation speed of the photosensitive drum, the rotation speed of a rotating device such as a fixing device or a developing device may be displayed.

In this way, in this embodiment, a pulse disk is mounted on the photosensitive drum shaft, and the number of rotations of the pulse disk, which moves together with the photosensitive drum rotated by the drive of a motor, is counted by a microcomputer via a photointerrupter. Since it is displayed on the display, the drum rotation speed can be accurately monitored, and the service person can easily reset the motor rotation speed during regular maintenance.

As explained above, the present invention provides a means for generating clock pulses corresponding to the rotational speed of a rotating body such as a motor, a counting means for counting the clock pulses generated by the means, and a counter for the counting means. Since it is equipped with a means for displaying the rotational speed of the rotating body based on numerical values, it is easy to detect abnormalities in the mechanical system, and the motor speed can be corrected to copy at a predetermined process speed that provides good image quality. child

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the internal configuration of a conventional device, FIG. 2 is a perspective view showing an example of the configuration of a drive system of the conventional device, and FIGS. A block diagram showing an example, FIG. 5 is a perspective view showing an example of the configuration of the drive system of the device of the present invention, FIG. 6 is an enlarged front view showing the shape of the pulse disk in FIG. 5, and FIG. Figure 1 is a circuit diagram showing an example of the configuration of the photointerrupter, Figure 9 is a signal waveform diagram of the output signal of the photointerrupter, and Figure 9 is a block diagram showing an example of the configuration of the control system of the device in Figure 5. FIG. 10 is a flowchart showing the operation of the apparatus of FIG. 9. /...Device main body, λ...Photosensitive drum, 3.
...Seventh charger, G...Exposure simultaneous charger, 5.
...Full surface exposure light source, ≦...Developer, 7...Transfer charger, Z...Cleaning device, Wa...
Original exposure light source, /θ...first moving mirror, l/...
...28th moving mirror, 12...Rengi, /3...Third fixed mirror, tG...Third fixed mirror, lj...
・Haraakidan stand, /6...Paper cassette, /7・
...Paper feed roller, 7g...Paper, /91. /92・Roller pair, 〃...conveying device, 2/,〃...roller pair, 23. , 232... Paper ejection roller pair, knob...
Paper output tray, 3θ...motor, 3/...gear,
3 no...gear, 33...pin, 3ri...gear, 3! ;...timing pulley, 36...timing belt, n...timing pulley, 3g, ff, ψ, g/, Q, g3,1411...
・Drive transmission mechanism, II5... Wire pulley, name...
・Wire, guar...gear, q/shaft,〃
...timing pulley, 5θ medium timing belt, ri/...timing pulley, j co...timing pulley, j3...electromagnetic clutch, j g...axis,! !・
...Timing pulley, j B...Timing belt, j
7. Timing pulley, 5g...shaft, j...gear, α...gear, 6/...electromagnetic clutch, Ω...pulse disk, 3. Photo interrupter, ROM... Read-only memory, RM...rate multiplier, O20...oscillator, Bc...binary counter, D
...Decoder, WS...Waveform synthesis circuit, SD...
Signal distributor, B...Amplifier, AC...AC power supply (commercial power supply), DI...Diode rectifier, TR/~T
R: Power transistor, D/~D: Protection diode, M: Three-phase motor, LOAD: Three-phase motor information, (3KEY: Numeric keypad, DISP: Display vessel, D
SW...Dip switch, (EPU...Microcomputer, M
TO...Motor control board (motor drive circuit), CLK
...Pulse signal, SW...Self-diagnosis mode changeover switch. Patent applicant Canon Co., Ltd. agent Patent attorney Yoshi Tani
VCC Figure 9

Claims (1)

[Scope of Claims] 1) Detection means for detecting the rotational speed related to the recording drum, and display means for displaying either the rotational speed detected by the detection means or the rotational speed converted based on the rotational speed. An electronic copying device characterized by comprising: 2. In the apparatus according to claim 1, the detection means includes a generation means for generating clock pulses corresponding to the detected rotational speed, and a clock pulse generated from the generation means for counting the clock pulses for a predetermined period of time. 1. An electronic copying apparatus comprising: a counting means for calculating the number of copies; 5) An electronic copying apparatus according to claim 1 or 2, wherein the detection means and the display means are operated by a mode selection means regardless of a copying operation. 4) In the apparatus according to claims 1 to 5, the motor for driving the recording drum is an inlet motor whose drive speed can be freely set, and further includes speed switching means for the motor. An electronic copying device characterized by: