JPS6015065B2 - Automatic stop device in copying machine - Google Patents

Description

[Detailed description of the invention] The present invention relates to an automatic stop and turn device for a copying machine.

The automatic stop device here refers to a device that disconnects the power supply path of the mechanical operation circuit of the copying machine after a certain period of time after the main switch is turned on and after the end of copying. Such an automatic stop device sets a time interval t3 after each copy cycle in which the next print cycle can be started immediately (copy standby state) by turning on the print switch within a relatively short time interval after the end of copying, for example. used for providing. The conventional automatic stop device for the copy standby state is triggered at the same time as the main switch is turned on, and the automatic stop time to until the intended stop of the copy standby state is set to a "fixed time" longer than the stabilization time t of the heating and fixing unit. If the time for one copy cycle is , then there is a relationship of to=t,+ra+etc.

However, the stabilization time t, varies depending on the outside temperature and the length of time left after the main switch is turned off, and therefore the waiting time for copying after copying also varies. This results in unnecessary operations that are several times to several tens of times longer than the copy standby time required for the actual button, which is very disadvantageous in terms of machine durability, power consumption, and the like. An object of the present invention is to activate the function of the automatic stop device of a copying machine that takes time to stabilize, such as a heat-fixing section, immediately after those elements are stabilized, thereby wasting copying waiting time after copying is completed. The goal is to reduce operating time. The present invention will be described below with reference to the illustrated embodiments.

In FIG. 1, the main switch SW has two stages. First, when the SW is set to "1", the power is turned on only to the fixing unit 10.
If C is only connected, the machine will not operate, and then when it is set to "2", power will be supplied to the control circuit 20, and from the operation and self-maintenance of the relay RAI in the circuit, which will be described later.
The mechanical operation circuit 30 is connected to the first stage contact "1" of the main switch SW via the contacts RAI-1 and RAI-2. When the main switch SW is released from the "2" state, it returns to the "1" state. Figure 2 is the first
This shows the control circuit 20 in the figure, which includes an automatic stop circuit 21 and a printed circuit 22.
and a temperature control circuit 25. Note that one part of the heater control circuit 11 shown in FIG.
It is designated by the reference numeral 11' in FIG. Automatic stop circuit 21
has a switching transistor Tr2 and switching transistors Tr3 and Tr4 connected in series with each other. The base of the transistor Tr2 is connected to the DC power supply bus 23.
, 23', and the emitter is connected to the bus 23, and the collector is connected to the resistor R3.
and capacitor C, to bus bar 23'. The base of the Darlington-connected transistor T3 is connected to this capacitor C via a resistor R, and a relay RAI for controlling the mechanical operation circuit 30 is inserted in the output circuit of Tr4. . Capacitor C
, and resistor R, acts to determine the de-energization time of relay RAI, that is, the automatic stop time.

The capacitor C is charged not only by the transistor Tr2 inserted between the connection point 28 and the bus 23, but also by the switching transistor Tr, which is also inserted between the connection point 28 and the bus 23 via the diode D. It is also controlled by This transistor Tr, is the temperature control circuit 25
a controlled switching element, e.g. thyristor 2, connected to
7, and turns off when the temperature of the fixing section 10 reaches a predetermined temperature. Now, when power is supplied to the control circuit 20 at the second stage of the main switch SW, the emitter of the transistor Tr2. Capacitor C2 is charged through the base and resistor R2, while transistor Tr2
becomes ON state.

Capacitor C, via transistor Tr2 and resistor R3.
is charged, and the charges stored in the capacitor C turn on the transistors Tr3 and Tr4. Relay RAI is energized and its contacts RAI-1 and RAI-2 are closed, and the entire circuit of control circuit 20 and mechanical operation circuit 30 enters a self-holding state. Then main switch S
Even if W releases his hand from the second stage state and returns to the first stage state, the circuit remains unchanged. Under this state, when the main switch SW is in the first stage, power is supplied to the heater 2 of the fixing unit 10 via the heater control circuit 11, and the fan motor 13 is activated. Unless we consider the effect of the transistor Tr, when the capacitor C2 is fully charged, the base current of the transistor Tr2 will stop flowing, the charging of the capacitor C will be cut off, and the charge of the capacitor C will be transferred to the resistor R, and the transistor Tr.
3. Discharge occurs via Tr4.

In other words, the function of the automatic stop circuit 21 starts working, and the capacitor C
After a certain period of time T determined by the values of , and resistor R, transistors Tr3 and Tr4 are turned OFF, deactivating relay RAI. Therefore, the power supply to the mechanical operating circuit 30 is interrupted. However, until the temperature of the fixing unit 10 reaches a predetermined temperature,
Capacitor C, transistor Tr, diode D,
Since the battery continues to be charged through the circuit, the function of the automatic stop circuit described above is inhibited, and its function starts working from the time when the transistor Tr is turned FF. The temperature control circuit 25 has a differential amplifier consisting of transistors Q and Q2, and until the temperature of the fixing section 10 reaches a predetermined temperature, the change in the resistance value of the thermistor 26 depending on the temperature is controlled by the transistor Q. , appears as the terminal voltage of resistor R5 connected to the collector of .

The transistor Q connected to this terminal via the Zener diode ZD is thereby made conductive, and the heater control circuit 1
1' and 11, the heater 12 is connected to a power source AC. Therefore, the temperature of the fixing section 10 increases. During this time, transistor Q2 is in a cutoff state. The thyristor 27 connects the temperature control circuit 25 and the transistor Tr so that it is ignited by the terminal voltage of a resistor R6 connected to the collector of the transistor Q2 of the temperature control circuit 25, and turns off the transistor T. ing.

That is, the thyristor 27 is inserted between the base of the transistor Tr and the bus 23', and its gate is connected to the resistor R.
7 to the collector of transistor Q2. Both transistors Q and Q2 of the differential amplifier are turned on and off relatively, and if the base voltage of transistor Q is lower than the base voltage of transistor Q2,
Transistor Q, is ○N and transistor Q2 is OFF
F, and if the base voltage of transistor Q, is higher than that of transistor Q2, transistor Q, becomes ○F.
F and transistor Q2 is turned on. The base voltage of the transistor Q depends on the resistance value of the thermistor 26, and the resistance value of the thermistor 26 depends on the temperature of the fixing section 10. Since thermistor 26 exhibits a large resistance value when it is closed, the base voltage of transistor Q is lower than that of transistor Q2 when it is cold, so that transistor Q. is 0N and transistor Q2 is OFF. Fixing section 10
When the temperature of the thermistor 26 rises and exceeds a certain value, the thermistor 26
The resistance value of transistor Q becomes smaller, and the base voltage of transistor Q becomes higher than that of transistor Q2, so that transistor Q is turned off and transistor Q2 is turned on. Therefore, while the temperature of the fixing unit 10 is lower than the predetermined temperature, the transistor Q2 is OFF as described above.
The thyristor 27 is OFF and the transistor Tr is ON. Therefore, after the main switch is turned on, until the predetermined fixing temperature is reached, the automatic stop circuit's capacitor C. It is expected that the transistor Tr will continue to be charged and the transistor Tr will be turned off. When the temperature of the fixing unit 10 reaches a predetermined temperature, the transistor Q2 becomes conductive and the thyristor 27 is turned on, so that the base potential of the transistor Tr falls and becomes OFF. Therefore, from this point on, the charge in the capacitor C is discharged through the low resistance R, transistors Tr3 and Tr4, and the automatic stop timer is then activated by the relay RA.
I becomes FF, and the mechanical operation circuit 30 is disconnected from the power supply AC. Incidentally, the thyristor 27 continues to turn on until the power supply DC is cut off, regardless of the temperature control circuit 25. As described above, according to the present invention, the automatic stop function starts working after an element that requires time to stabilize, such as the fixing section 10, is stabilized.

The automatic stop time T is determined by the time constants of the capacitor C and the resistor R, so by setting this time T to a desired length, the automatic stop time T is always constant regardless of the fluctuating stabilization time. Copy waiting time can be created. Therefore, it is possible to eliminate wasted operation time during copy waiting time after copying. In order to create a copying standby time immediately after copying is completed, a printed circuit 22 as shown in FIG. 2, for example, may be provided.

In the case of this printed circuit 22, the printed switch SW,
When is pressed, relay RA2 is energized through the switch, its contact RA2-1 is closed, and copy operation circuit 24 is activated through repeat switch SW2, which remains closed until a predetermined number of sheets have been copied, and diode D2 and resistor R3 are activated. Capacitor C, continues to be charged through. Therefore, capacitor C is charged until a predetermined number of copies are completed. When copying is completed, repeat switch SW2 is opened for a moment, which deenergizes relay RA2.
Relay contact RA2-1 opens, and from this point on, the capacitor C starts discharging. Therefore, relay RAI is turned off after a certain copying standby time has elapsed after copying is completed.
When turning off all the circuits including the heater 12, the main switch SW is manually returned to the OFF position from the first stage.

Note that it is advantageous to use a planar heating element for the heating element of the fixing section, which does not require rotation of the fixing roller.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an electric circuit of a copying machine having an automatic thickness device according to the present invention, and FIG. 2 is a diagram showing a part of the electric circuit in a control section thereof. 10... Fixing unit, 11... Heater control circuit, 12... Heater, 20... Control circuit, 2
1... Automatic stop circuit, 22... Printed circuit, 24... Copy operation circuit, 25...
... Temperature control circuit, 26 ... Thermistor, 27 ... Thyristor, Tr, ... Transistor, C, ... Capacitor, R, ... Resistor, SW ... Main switch,
SW. ...Print switch. Figure 1 Figure 2

Claims (1)

[Claims] 1. For copying machines that include elements that require time to stabilize after the main switch is turned on, the automatic stop circuit that closes off the power supply path of the machine operating circuit after a certain period of time after the main switch is turned on, and the automatic stop function described above, are prohibited from starting. a first switch means and a second switch means connected to an automatic stop circuit;
The inhibiting operation of the first switch means is canceled when copying is completed,
The prohibited operation of the second switch means is configured to be canceled by a switch element that operates when the above-mentioned element that requires time to stabilize is stabilized, and when both switch means are released, the automatic stop function of the automatic stop circuit is activated. An automatic stop device characterized in that it is configured to start.