JPH0314181B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus having a switching function between a normal copying operation mode and an adjustment operation mode during adjustment.

2. Description of the Related Art Generally, in an image forming apparatus such as an electronic copying machine, when adjusting a timer time or the like during an assembly process, the adjustment is performed by connecting a time measuring device, a synchroscope, etc. to the copying machine. Furthermore, in the case of readjustment due to parts replacement by the user, the adjustment work is performed by connecting the measuring device to the copying machine in the same manner as described above. As described above, in the past, adjustment could not be performed without using various measuring instruments each time, which was extremely inconvenient.

The present invention has been made in view of the above circumstances, and its purpose is to provide a switching means for more reliably and safely switching between a normal copying operation mode and an adjustment operation mode during adjustment, and to switch between the adjustment operation mode and the adjustment operation mode. By providing a control means that generates a signal corresponding to the adjustment content when switching, performs adjustment operation using this signal, and displays the result, it is possible to easily perform various adjustments without a measuring device. An object of the present invention is to provide a forming device.

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

In FIGS. 1 and 2, reference numeral 1 denotes a main body of a copying machine, and a document table 2 is provided on the upper part of the main body 1 so as to be movable back and forth in the direction of arrow a. Also, main body 1
An operation panel 3 is provided on the top of the unit, and the operation panel 3 includes a power switch 4, a copy switch 5, a keyboard 6 for setting the number of copies, a number of copies display 7, a copy density adjustment dial 8, and a check button for abnormalities. Lamp 9, paper supply lamp 10, power lamp 1
1, a ready lamp 12, a cumulative counter 13 for cumulatively totaling the number of copies, and the like. On the other hand, a photosensitive drum 14 that rotates in the direction of arrow b in the figure is provided approximately at the center of the main body 1 . A charger 1 for charging is provided around the photoreceptor drum 14.
5, an exposure device 16, a developing device 17, a transfer charger 18, a peeling charger 19, a static elimination charger 20, a cleaning device 21, and the like are arranged radially.
Further, between the charger 15 and the exposure device 16, a static eliminator, for example, a static eliminator lamp 22, which removes the charges on the photoreceptor drum 14 is provided. A paper cassette 23 is detachably provided at the bottom of the main body 1, and the paper supplied from this cassette 23 is conveyed through a conveyance path 24 and passed between the photoreceptor drum 14 and the charger 18. then fuser 2
5, and then from the discharge port 26 to tray 2.
7. Note that 28 in FIG. 2 is a toner replenishing device, and 29 is a dust collecting device.

FIG. 3 shows the control circuit of the above-mentioned copying machine.
In the figure, 30, 31, 32, and 33 are the original platens 2, respectively.
Document platen position switch that detects the position of document platen 2
document platen passage switch that detects the passage of paper, paper ejection port 2
6, an exit switch under the paper ejection roller 6, and a paper stop switch that detects the position of the paper. Signals from these switches, a signal from the copy switch 5, and a signal from the copy number setting key 6 are input to the input interface circuit 34. has been done. Various signals from this input interface circuit 34 are input to a microprocessor 35. This microprocessor 3
5 receives a clock signal from a clock oscillator 36 having a ceramic oscillator. Further, this clock signal is inputted to the input interface circuit 34 through a frequency division counter 37. The output of microprocessor 35 is input to output interface circuit 38. From this output interface circuit 38, a clutch 39 for advancing the original platen, a clutch 40 for retracting the original platen, a clutch 41 for paper supply, a clutch 42 for paper transport, a cumulative counter 13, an exposure device 16, and a static elimination lamp 22.
outputs various control signals and heater adjustment control signals. Further, a display storage shift register 43 is provided for storing each status display information from the microprocessor 35 for displaying each status of the copying machine.
Added to 5. This segment driver 44
displays the number of copies currently copied on the copy number display 7.
The lamp driver 45 displays various current statuses of the copying machine on the power lamp 11, paper supply lamp 10, check lamp 9, and ready lamp 12. Further, the fixing heater control circuit 46 detects the temperature with a thermistor 47 to generate a fixing enable signal, sends this to the input interface circuit 34, and receives a heater adjustment control signal from the output interface circuit 38 to adjust the phase. An angle control signal is generated and applied to phase angle control element 48 and input interface circuit 34. The conduction time of the fixing heater 49 connected to the phase angle control element 48 is controlled by a control signal that controls the current conduction angle.
Heater heating is thereby controlled. Further, when the power of the copying machine is turned on, the microprocessor 35 and the fixing heater control circuit 46 are reset to the initial state by the initial reset circuit 50.

Details of the fixing heater control circuit 46 are shown in FIG. 4. In the figure, the supply voltage Vcc to the circuit
A resistor connected in series between
R ₁ , R ₂ , a resistor R ₃ connected in series, and a thermistor 47 for detecting the fuser temperature are provided in parallel as a bridge for temperature detection, and the common connection point of the former is the resistor R 3 .
It is connected to the inverting input terminal of the detected temperature determination comparator 51 via R ₄ , and the latter common connection point is connected to the non-inverting input terminal of the comparator 51 via resistor R ₅ . This comparator 51
The output terminal e of is connected to the comparator 51 via the resistor _R6 .
The output terminal e is connected to the input interface circuit 34 for sending out a fixable signal. The output terminal e of this comparator 51 is connected to the power supply Vcc through a resistor _R7 , and is connected in series to a timer for controlling the heater phase angle through a resistor _R8 and a variable resistor _VR1 for setting the maximum conduction angle. It is connected to the input terminal I ₂ of an IC (NE555 manufactured by Signetics) 52. Additionally, a flip-flop 5 is provided between the power supply Vcc and the ground GND to memorize the fixing possible state.
The heater adjustment control signal from the output interface circuit 38 is input to the set input terminal S of No. 3 through the OR circuit OR, and the output of the comparator 51 is also input, and the reset input terminal R receives the initial input signal. An initial reset signal from reset circuit 50 is input. On the other hand, the output terminal Q of this flip-flop 53 is connected to the above-mentioned timer.
Connected to input terminal _I5 of IC52. This timer IC 52 is provided between the power supply Vcc and the ground GND, and its input terminal I ₁ is connected to the power supply Vcc via a resistor R ₁₀ and to the collector of the transistor Q ₁ . Input terminals I ₃ , I ₄
is connected to the power supply Vcc via a resistor _R11 , to the ground GND via a timer capacitor _C1 , and to the collector of the transistor _Q1 via a diode _D1 with the polarity shown. This transistor Q ₁
The emitter of is connected to ground GND, and the base is connected to the collector of transistor Q ₂ through a Zener diode ZD and diode D ₂ of the polarity shown in series. A common connection point between these diodes ZD and _D2 is connected to the power supply Vcc via a resistor _R9 . Also, the emitter of the above transistor _Q2 is connected to the ground GND.
The base thereof is connected via a resistor _R14 to the output end of a rectifier circuit 54, which is composed of a transformer _T1 and diodes _D3 and _D4 , and rectifies alternating current AC. Furthermore, a capacitor C ₂ and a resistor are connected between the base of this transistor Q ₂ and the ground GND.
R ₁₃ is provided in parallel. Further, the center tap of the transformer _T1 of the rectifier circuit 54 is connected to the ground GND. On the other hand, the output terminal O ₁ of the timer IC 52 is connected to the power supply Vcc via the bidirectional photothyristor 55 and resistor R ₁₂ as shown in the figure, and the phase angle control signal is output from the output terminal O ₁ to the phase angle control signal. It is output to the angle control element 48.

Figure 5 shows the timer IC5 for controlling the heater phase angle.
This is the detailed circuit of No. 2. In the figure, 56, 57
is a threshold comparator, and the non-inverting input terminal of this comparator 56 is connected to the terminal _I3 into which the threshold voltage is input,
The inverting input terminal is connected to a terminal _I2 for threshold voltage control and also to a terminal _I0 for power supply Vcc via a resistor _R15 . The inverting terminal of the comparator 57 is connected to the terminal _I1 to which the trigger input is applied, and the non-inverting terminal is connected to the resistor _R16.
It is connected to the inverting terminal of the comparator 56 via a resistor R17, and to the ground terminal _I6 via a resistor _R17 . These resistors R ₁₅ to _{R 17} are threshold level and trigger level setting resistors, and each has the same resistance value. The output terminal of the comparator 56 is connected to the reset terminal R of the flip-flop 58, and the output terminal of the comparator 57 is connected to the set terminal S of the flip-flop 58. The clear terminal of flip-flop 58 is connected to terminal _I5 . The output terminal of the flip-flop 58 is connected to the base of a transistor 60 for controlling capacitor discharge, and is also connected to the output terminal O ₁ via an inverter buffer 59. The collector of the transistor 60 is connected to the timer capacitor discharge output terminal _I4 , and the emitter is connected to the ground terminal _I6 .

In the electronic copying machine configured as described above, when the power is turned on, the initial reset circuit 50 is activated and the power is turned on to the fixing heater 49.
In this state, when the fixing device 25 reaches a temperature that allows fixing, the ready lamp 12 lights up and the copy standby state is entered. When the copying switch 5 is pressed here, the paper conveyance device is operated, and the paper is conveyed from the paper cassette 23 to the paper stop switch 33 by the paper supply clutch 41 and then stopped. Paper stop switch 3
3 operates, the document table advancement clutch 39 operates, and the document table 2 moves forward. At the same time, the exposure device 16 operates, and the photoreceptor drum 14 is exposed to the original.
When the original platen 2 operates the original platen passage switch 31, the paper conveyance clutch 42 is operated, and the paper is conveyed again and guided to the transfer charger 18. A charger 15 for charging is provided on the surface of the photoreceptor drum 14.
A constant charge is given by . If the surface of the photoreceptor drum 14 is exposed in this state, a latent image of the document is formed on the surface of the photoreceptor drum 14. Toner is adsorbed to this latent image by the developing device 17,
This is transferred onto a sheet of paper conveyed by the transfer charger 18 to form a visible image. The paper with this image is fixed through the fixing device 25, and is discharged to the tray 27 from the paper discharge port 26 by the paper discharge roller. In preparation for the next copying process, the surface of the photosensitive drum 14 is cleaned by the cleaning device 21, and at the timing when the paper stop switch 33 is released from the paper, the document platen retreating clutch 40 is activated to move the document platen 2 to the normal position. At the same time, the exposure lamp of the exposure device 16 is turned off.

Next, the operation of the control circuit of the copying machine shown in FIGS. 3 to 5 will be explained. First, when the power switch is turned on, an initial reset signal is output from the initial reset circuit 50 as shown in FIG. 3, and the flip-flop 53 of the fixing heater control circuit 46 is reset. This flip-flop 5
Since the output Q of 3 is applied to the input terminal _I5 of the timer IC52, this input terminal _I5 is at the "L" level.
OV, thereby resetting the flip-flop 58 in FIG. Therefore, the output of the flip-flop 58 becomes "H" level OV, and this output becomes "L" level via the inverter buffer 59, and the bidirectional photothyristor 5
5, so this photothyristor 55
is always on. This photothyristor 5
The output signal from 5 is input to the fixing heater 49 through the phase angle control element 48 as shown in FIG.
%) state. This state continues until the temperature T _H detected by the thermistor 47 in the fixing device 25 increases as the heater 49 heats it and reaches the fixable set temperature T _S. Then, when the temperature T _H detected by the thermistor 47 becomes higher than the set fixing temperature T _S , the output of the temperature detection comparator 51 changes from the "L" level OV to the "H" level Vcc.
This "H" level signal is applied to the set terminal S of the flip-flop 53 via the OR circuit OR, so that the flip-flop 53 is set.
On the other hand, in order to notify this fixable state, the "H" level signal of the comparator 51 is sent as a fixable signal to the microprocessor 35 through the input interface circuit 34. At the same time, the set output Q of the flip-flop 53 becomes "H".
The potential of the input terminal _I5 of the timer IC52 becomes "H" level Vcc due to the level signal, so the timer IC52
The reset state of the flip-flop 58 in the flip-flop 2 is released. As a result, the fixing heater 49 shifts from full lighting to heater phase angle control lighting. After that, the temperature of the heater 49 is set to the fixing temperature T _S
Temperature control is performed using phase angle control so that

Next, a temperature control operation by controlling the phase angle of the fixing heater 49 using the timer IC 52 will be described. The alternating current power supply AC in FIG. 4 is common to the power supply applied to the fixing heater 49, and is full-wave rectified via a transformer T1 and diodes _D3 and _D4 , and this rectified voltage is passed through a resistor _R14. is applied to the base of transistor _Q2 . At this time, this transistor _Q2 is turned off only near the zero cross point of the AC power supply AC. The collector output signal of this transistor Q ₂ is waveform-shaped by a diode D ₂ , a Zener diode ZD, and a transistor Q ₁ , and is then used as a synchronization signal for controlling the phase angle at a terminal I ₁ for trigger input of the timer IC 52 .
It is also applied to terminal I ₃ for the threshold voltage input and terminal I ₄ for the capacitor discharge output through diode D ₁ . First, when the synchronizing signal (collector output signal of transistor _Q1 ) is at the "L" level OV, the charge in the capacitor _C1 is discharged to the ground GND through the transistor _Q1 shown in FIG. At the same time as this capacitor C1 is discharged, the trigger comparator 57 (Fig. 5) is activated by the above-mentioned "L" level synchronization signal.
The output of the flip-flop becomes the "H" level Vcc, and this "H" level signal is applied to the set input terminal S of the flip-flop 58.
8 is set. Therefore, the potential of the output terminal _O1 of the timer IC 52 becomes "H" level, and this "H" level signal is transmitted to the photothyristor 5 in FIG.
5, the photothyristor 55 is turned off. That is, near the zero cross point, the heating of the heater 49 is always turned off.

Next, when the synchronization signal changes from the "L" level to the "H" level, the capacitor _C1 is connected to the power supply.
Charging is started from Vcc via resistor _R11 . The charging voltage level of this capacitor _C1 (point c in Figure 4)
reaches the voltage level of the threshold voltage control terminal _I2 of the timer IC 52 (point d in Fig. 4), the threshold comparator 56
The output becomes "H" level. Since the "H" level output signal of the comparator 56 (FIG. 5) is applied to the reset terminal R of the flip-flop 58, the flip-flop 58 which is in the set state is reset. Therefore, the potential of the output terminal _O1 of the timer IC52 becomes "L" level, and this "L" level
Since the level signal is input to the photothyristor 55, the photothyristor 55 is turned on, and the heating of the heater 49 is turned on. At this time, the "H" level output signal of the flip-flop 58 is applied to the base of the transistor 60, so that the transistor 60 is turned on.
The charge stored in the capacitor _C1 through the transistor 60 in the on state is instantly discharged to the ground GND. The bidirectional photothyristor 55 maintains the on state until the synchronization signal (collector output signal of the transistor _Q1 ) reaches the next "L" level OV, that is, near the zero cross point. Therefore, the fixing heater 49 is turned on by the conduction angle θ through the phase angle control element 48.
The above conduction angle θ is determined by the potential level of the terminal I ₂ (point d) for threshold voltage control of the timer IC 52 because the charging curve of the capacitor C ₁ is constant.
It changes depending on the value of. In other words, when the input voltage to terminal _I2 is low, the conduction angle θ becomes large,
When the value is high, the conduction angle θ becomes small. here,
The input voltage to the terminal 12 changes according to the change in the resistance value of the thermistor 47.

Therefore, temperature control of the fixing device 25 is performed as follows. First, when the temperature of the fuser 25 becomes lower than the set temperature T _S , the resistance value R _H of the thermistor 47 becomes larger than the set resistance R ₂ of the temperature detection bridge, so the output of the comparator 51 for temperature detection The potential at point (point e) is
Along with this, the "H" level gradually decreases from Vcc,
“L” level OV. However, the fixable signal remains retained. Also, in conjunction with these operations, the potential (point d) applied to the threshold voltage control terminal 12 of the timer IC 52 gradually becomes lower than the potential at the fixable set temperature Ts, so the timer IC 52 As mentioned above, the conduction angle is made larger than that at the set temperature Ts for fixing.
It works to raise the temperature of the fixing device 24. Conversely, when the temperature of the fixing device 25 becomes higher than the set temperature T _S , the resistance value R _H of the thermistor 47 becomes smaller than the set resistance R ₂ of the temperature detection bridge.
Output point of comparator 51 for temperature detection (point e)
Accordingly, the potential gradually rises from the "L" level OV and reaches the "H" level Vcc. Therefore, the potential ( _d
Since the potential at point ) gradually becomes higher than the potential at the fixable set temperature Ts, the conduction angle θ of the fixing heater 49 becomes smaller, contrary to the above, and works to lower the temperature of the fixing device 25. In this way, the fuser 2
The temperature No. 5 is automatically controlled to be the fixable set temperature T _S.

Further, when the temperature T _H detected by the thermistor 47 in the fuser 25 is sufficiently lower than the set temperature T _S for fixing, for example, when using a copying machine installed in a cold region, the conduction angle θ of the fuser heater becomes large enough. However, in order to reduce the power consumption of the entire copying machine and to prevent the paper from igniting in the fuser 25, the maximum conduction angle θmm of the fuser heater 49 is set to a fixed value, for example 70 mm.
It is necessary to adjust the setting to %. For this a timer
Terminal I ₂ for threshold voltage control of IC52
The potential applied to (point d) is adjusted so that it does not become lower than a certain potential using the variable resistor VR ₁ for setting the maximum conduction angle and the constants of resistors R ₇ , R ₈ , R ₁₅ , R ₁₆ , and R ₁₇ . There is a need.

Conventionally, a measuring device such as a synchroscope is used for this adjustment, but in the present invention, without using a measuring device, the optimum maximum conduction angle of the phase angle control of the fixing heater 49 can be determined using the control device of the copying machine itself. θmm can be adjusted, which will be explained next with reference to the flowchart of FIG. The HF flag shown in FIG. 6 is a register provided in the microprocessor 35 that stores the "H" level ("1" level) state of the phase angle control signal (FIGS. 3 and 4). , H.CNT is a register provided in the microprocessor 35 that adds up the number of times the processor 35 executes the count routine CR only while the phase angle control signal is at the "L" level.

Now, when the power is turned on to the copying machine at step _S1 , the initial reset circuit 50 is turned on at step _S2 .
The microprocessor 35 and the flip-flop 53 of the fixing heater control circuit 46 are set to the initial state by an initial reset signal from the fusing heater control circuit 46. Next, in step _S3 , when a signal that is not input at the same time in the normal use mode, for example, the copy switch 5 and the "0" key of the copy number setting key 6 are turned on at the same time, both signals are input to the microprocessor 35. , the microprocessor 35 performs a maximum conduction angle θmm setting routine (step _S5) of the fixing device 25.
~ _S17 ) and execute each step in sequence. If the above keys are not turned on at the same time in step _S3 , a copy operation is executed in the normal copy mode in step _S4 . When the microprocessor 35 enters the maximum conduction angle setting routine, it first converts the heater control signal into a pulse signal with a pulse width of 1 ms in steps _S5 to _S7 , and fixes this pulse signal through the output interface circuit 38. (FIG. 3, FIG. 4). This adjustment control signal passes through the OR circuit OR of the fixing heater control circuit 46, and the flip-flop 53 is set. That is, the timer is activated by the "H" level set output signal of the flip-flop 53.
Since the flip-flop 58 of the IC 52 is released from the reset state, the fixing heater 49 shifts to heater phase angle control lighting as described above. Here, as shown in FIG. 4 by inputting the heater control signal to the OR circuit OR, the normal temperature control of the heater 49 is completely ignored and executed. In this state, when the copy switch 5 is turned on in step _S8 , that is, the start key for adjustment is turned on, the phase angle control signal from the output terminal _O1 of the timer IC 52 is transferred to the input interface circuit 34.
The data is inputted to the microprocessor 35 through the microprocessor 35.
Next, if this phase angle control signal is at the "H" level in step _S9 , the HF flag is set to "1" in step _S10 , and if not, the HF flag is set to " ₁ " in step S11. 1” is determined. That is, the change of the phase angle control signal from "H" level to "L" level is confirmed. If the HF flag is set to "1" in these steps _S9 to _S11 , then steps _S12 to _S14
, count the "L" level time of the phase angle control signal with H・CNT, and determine that the phase angle control signal is
When the next "H" level is reached, at step _S15 ,
The count contents of H.CNT are displayed on the copy number display 7 through the display storage shift register 43 and the segment driver 44. If the time count number N of the "L" level of the above phase angle control signal is performed using a soft timer with a period of 0.5 msec as in step _S14 , if the commercial frequency is 50 Hz, half the period will be
Since it is 10 msec, the conduction angle θ can be directly determined as N/10/0.5×100 [%]. The count number N of H·CNT may be displayed as is on the display 7, or the result calculated using the above formula may be displayed on the display 7. The display time on the display 7 is displayed for 5 seconds at step _S16 , and thereafter, at step _S17 , the HF flag and H.CNT are reset to the initial value "0". In this state, if the variable resistor VR1 for setting the maximum conduction angle (Fig. 4) is adjusted again and the copy switch 5 is turned on again, the time when the phase angle control signal is at the "L" level is counted again, and the number of counts is calculated. The number of copies is displayed on the copy number display 7.
By executing the flowchart operation shown in FIG. 6 as many times as possible while adjusting the variable resistor VR1 in this manner, it is possible to set the optimum maximum conduction angle θmm.

In the above embodiment, the operation time of the fixing heater 49 is adjusted by providing a function of adjusting the conduction angle of the fixing heater 49 using a phase angle control signal, but the operation time of the fixing heater 49 is adjusted using the phase angle control signal. For example, in order to match the leading edge of the paper conveyed in the conveyance path 24 and the image on the surface of the photoreceptor drum 14, the paper conveyance may be started by adjusting the time from when the start key is turned on until the paper conveyance starts. The time measurement of other signals such as signals may be performed by a microprocessor.

As described above, according to the image forming apparatus of the present invention, there is provided a means for switching between a normal copying operation mode and an adjustment operation mode during adjustment, and when switching to this adjustment operation mode, a signal corresponding to the adjustment content is sent. By providing a means for generating a signal, performing an adjustment operation using this signal, and displaying the result, it is possible to utilize the necessary functions of a copying machine, without increasing the price, and without using a measuring device. An image forming apparatus that can easily and accurately perform adjustment operations can be provided. In other words, among the means for executing the adjustment operation of the image forming apparatus, in particular, at least the above-mentioned time measuring means and signal generating means are also used as the control means conventionally provided in the image forming apparatus for executing the image forming operation. Moreover, the cost of the image forming apparatus is reduced because it does not require special switches or the like to switch from the normal copy operation mode to the adjustment operation mode, and is configured so that the conventional operation means can also be used. Adjustment operations can be performed through simple operations while suppressing the rise.

[Brief explanation of drawings]

1 is an external perspective view showing the overall structure of a copying apparatus according to an embodiment of the present invention, FIG. 2 is a side view showing the internal structure of the apparatus shown in FIG. 1, and FIG. 4 is a detailed circuit diagram of the fixing heater control circuit in FIG. 3, and FIG. 5 is a detailed circuit diagram of the fixing heater control circuit in FIG.
FIG. 6 is a detailed circuit diagram of the phase angle control timer IC shown in the figure, and FIG. 6 is a diagram showing a flowchart of time adjustment. 1...Copy machine main body, 5...Copy switch, 6...
...Copy number setting key, 7...Copy number display, 1
4... Photosensitive drum (photosensitive member), 15... Charger for charging, 16... Exposure device, 22... Static elimination lamp, 25... Fixing device, 35... Microprocessor, 43... For display storage Shift register, 44...
... Segment driver, 46 ... Fixing heater control circuit, 47 ... Thermistor, 48 ... Phase angle control element, 49 ... Fixing heater, 52 ... Timer IC for heater phase angle control.

Claims (1)

[Scope of Claims] 1. Various process means for executing image forming operations, an operation means provided with a plurality of keys for setting various conditions for image formation by the process means, and an operation means for the operation means. The image forming apparatus has a display means for displaying various set conditions, and a control means for controlling the various process means according to the various conditions set by the operation means, and further performs an image forming operation. In an image forming apparatus capable of switchably setting a forming mode and an adjustment mode for executing various adjustment operations different from this image forming mode, the image forming mode and the adjusting mode can be set by using a plurality of keys of the operating means. a switching means for switching when the adjustment mode is set by the switching means, and a power control means for supplying power to the part to be adjusted for a predetermined conduction time; a setting means for variably setting the conduction time of the power control means; a timekeeping means for measuring the conduction time changed by the setting means; and a signal according to the time measurement result of the timekeeping means outputted to the display means. An image forming apparatus comprising: a signal generating means for executing a display corresponding to the time measurement result, wherein the control means also serves as at least the signal generation means and the time measurement means.