JPS60263133A - Variable power copying machine - Google Patents

Abstract

PURPOSE:To eliminate inconvenience during the replacement of a process unit while an automatic unmagnification mode resetting means is provided by turning of the automatic unmagnification resetting means when the process unit is detached from the main frame. CONSTITUTION:An electrostatic charging electrode and an electrostatic discharging lamp 16 are formed as one process unit 6 together with a photosensitive drum 5 as an electrostatic image carrier, developing and cleaning device, etc., and the unit is fitted detachably while slid on a rail type holding member provided to the copying machine frame. A switch SW which is pressed with an end part 6a of the process unit 6 while the process unit 6 is attached to the copying machine frame is fixed. When the process unit 6 is detached from the copying machine frame, the switch SW is closed automatically to connect a power circuit which is not shown in a figure, and a voltage having the same level with +VB is applied to a point P1 of an automatic magnification resetting control circuit I, thereby stopping magnification resetting operation.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an improvement in a variable-magnification copying machine equipped with a mechanism for automatically returning the copying state of the copying machine to the same-magnification copying state after a copying operation. It is.

[Prior art]

Variable-magnification copying machines currently in practical use use buttons, knobs, levers, etc. to operate buttons, knobs, levers, etc. to change the magnification when copying at a reduced or enlarged magnification, but even after the magnification copying operation is completed, the magnification is automatically changed to the same size. Therefore, in order to perform the next same-size copy, it is often necessary to manually return the copying machine to the same-size copy state.

Looking at the usage status of such variable-magnification copying machines, 80% of the copy requests are
Since images above z are equal-size copies, currently used variable-magnification copying machines make copies without confirming whether they are equal-size copies or magnification copies before copying due to user carelessness or inexperience. When the work begins, a copy with an undesired magnification may be obtained and the entire copy may be wasted. Therefore, in a variable-magnification copying machine, it is absolutely necessary to confirm the magnification selection before making a full-size copy, but this confirmation is troublesome for the user, and moreover, it is easy to forget due to carelessness. There are many things.

Japanese Patent Publication No. 57-58658 proposes a method for preventing such errors in copying operations.

The above proposal automatically changes the copying state of the copying machine to the same size when the copying machine remains in an idling state, that is, a non-copying state, for a predetermined time interval or more from the completion of a magnification copying cycle or the completion of a magnification selection operation. The present invention proposes a variable magnification copying machine that is configured to return to the copying state and is convenient for the user because it does not require confirmation or operation of magnification selection as described above.

However, if the above proposal is applied to a variable magnification copying machine that is equipped with multiple process units containing monochromatic toners such as red and blue in addition to the commonly used black toner, the process Since the idling state continues for a long time due to unit replacement, a problem may arise in that the set variable magnification mode is switched to the same magnification mode in the middle of copying.

In such a case, if the user attempts to obtain variable-resolution copies with the same magnification in different colors, or to obtain multicolor copies by overlapping them, the user must check the magnification each time the process unit is installed.
This results in the proposal of an extremely inconvenient variable-magnification copying machine that requires settings to be made.

[Purpose of the invention]

The uninvented invention has an automatic resetting means for returning the variable magnification mode to the same magnification mode after a predetermined period of time after copying is completed, but on the other hand, this causes inconvenience when replacing the process unit. The purpose of this invention is to provide a variable magnification copying machine that does not

[Structure of the invention]

The present invention is configured such that, for example, a switch fixed to the copying machine body is activated by ejecting the process unit, thereby applying a specified voltage to the automatic magnification return control circuit to stop the return to the same magnification mode. to do,
At least in a copying machine in which a process unit having a drum can be inserted and removed from the main body, there is a copy magnification setting section that converts the copy magnification into a constant magnification mode and a variable magnification mode, and a variable magnification mode after copying is completed, such as after a certain number of seconds. This is achieved by a variable magnification copying machine, characterized in that the automatic reproduction means returns to the double mode, and the automatic reproduction means is inactivated when the process unit is removed from the main body. .

〔Example〕

FIG. 1 shows the automatic magnification return control circuit of the variable-magnification copying machine of the present invention, FIG. 2 shows the structure of the main body, and FIG. 3 shows the structure of the process unit.

11141 As shown in FIG.
is used in combination with a magnification selection circuit II which is a copy magnification setting section.

That is, first, the magnification selection circuit II will be explained.
A line 11 supplied with power from the power supply vll through relay contact a-1 and a ground line 1. Between the magnification selection pushbutton switches SWI, SW2, SW3 and the keep relay R,
, 1, and RL 2 are connected in series through a group of diodes. To explain in detail, one contact of the push button switch SWI for equal magnification selection is connected to the power supply line II, and the other contact is connected to the reset R3 terminal of the relay RL l via the diode D, and then to the reset R3 terminal of the relay RL l via the diode D11. They are connected to the reset terminals of R8 and R2, respectively.

One contact of the push button switch SW2 for copying with a magnification of 1 is connected to the power supply line 1. The other contact is connected to the terminal S1 terminal f- of the relay R1,1 through a diode D6 and to the reset R7 terminal of RL2 through a diode DIl, respectively. One contact of the push button switch SW3 for magnification 2 copying is connected to the power supply line 11, and the other contact is connected to the reset R1 of the relay RL1 via the diode D8.
to end E and through diode D, relay R1-2
are respectively connected to the set S2 terminals of . Relay R
The other ends of ,,1°RL2 are connected to the ground line 12, respectively. The diode groups D6 to D++ are grouped to prevent signal wraparound, and are connected to magnification selection push buttons SWI, SW2, SW3 and relays R, .

It is connected to RL2 so that the switch side is the anode and the relay side is the cathode. On the other hand, diodes D and D are connected between set terminal Sl and reset terminal R7 of keep relay R, 1 and ground line l, respectively, with their anodes facing ground line l, respectively. Diodes Dw3 and Dw3 are connected in the same direction between the cent terminal S2 and reset terminal R7 of RL2 and the ground line l, respectively. Diodes D, , D, ~D are surge absorbing diodes of keep relay RL 1°R142.

Next, the control circuit I of the automatic magnification return mechanism will be explained. The power supply line I and the ground line I.

Resistors R, , R, , R3 are connected in series between the lines 1 , . The collector is connected to the input terminal A of the timer circuit ■ (encircled by the dashed line), which will be described later, through the diode D. In between is a capacitor and a stabilizer for the operation of the transistor TRI.

A resistor R4 is connected that acts as a resistance when discharging J, and a variable resistor R and a capacitor CI are connected in parallel with this resistor R4.
are connected. Further, a diode D is connected between the input terminal A and the connection point between the variable resistor 8 and the capacitor C1, with the input terminal A side serving as a cathode. This diode D is provided with a comparator C which is used in the forward direction when discharging the capacitor C1 to shorten the time required for discharging.

Its reference voltage input terminal is connected to the connection point P3 of the resistor 5 and R6 connected in series between the power supply 8 and the ground line 1, and the other input terminal is connected to the ψ of the variable resistor vR and the capacitor C1. connected to a comma. The output terminal of comparator C is taken out from output terminal B of timer circuit l. A diode D2 and a resistor R7 are connected between the reference voltage input terminal and the output terminal of the comparator C, with the anode facing the input terminal side.
are connected in series. This diode D is a diode for preventing inflow from the comparator C output terminal.

The power source 8 also functions as a power source for the comparator C.

Next, the operation of the automatic magnification return mechanism control circuit will be explained.

The magnification of variable magnification copying machines is selected using the push button switch SW.
1, S W 2 , S W 3 dJ: This is performed by operating the iron magnification selection keep relays RL1 and RL2, but the mechanism itself is well known, so a description thereof will be omitted. Copy magnification can be selected using keep relays RLl and R.
This is done by combining the L2 contacts and outputting a selection signal for each magnification, and from the moment this selection signal is issued, the magnification variable device is driven to vary the copying magnification. The variable magnification drive signal, which is one of the operation stop signals, is output only while the variable magnification device is being driven.

The operation stop signal of this automatic magnification return control circuit is voltage +v8
When this level is applied to point P, the potential difference between the emitter and base of transistor TRI disappears, and TRI becomes inoperable.

When the driving of the variable magnification device is completed, the copying machine becomes ready for magnification copying, and copying can be performed at a selected specific magnification. Furthermore, it is also possible to select another copying magnification and copy at another magnification. In this case, when the magnification selection operation is performed, the above-mentioned operation is repeated, and after completion of driving, the state becomes available for copying again at the new magnification.

Automatic magnification return control circuit I and magnification selection circuit II are supplied with voltage from power supply V11 via relay contact a-1.

Relay contact a-1 is operated in conjunction with the copying mechanism to be open during the copying cycle of the copying machine and closed after the copying cycle is complete. Therefore, during the copy cycle, the power supply voltage of automatic magnification return circuit I and magnification selection circuit II is cut off, so that automatic magnification restoration mechanism and magnification selection function are not provided.

Now, assuming that the copying machine is in a state where copying is possible, relay contact a
-1 is closed and voltage across circuits I and II.

is applied. At this time, press buttons SW and SW for magnification selection are pressed.
Assume that 2 is pressed and magnification 1 is set.

When the transistor TRI becomes conductive and an input signal is supplied to the input terminal A of the timer circuit (2), the voltage at point P2 changes according to the time constant determined by the variable resistor VR and the capacitor C1.
2 is rising, while the reference voltage of comparator C is across resistor R.
5 and R5 is a constant voltage at point P, which is divided by R5 and R5. When V2 becomes higher than ■, the comparator C operates and the voltage at the output terminal B of the comparator becomes the ground voltage.

Output terminal B while comparison input voltage v2 is lower than reference voltage V
is holding +v8 (■), and output terminal B is strongly +V
8 (V), there is no potential difference between the emitter and base of the transistor TR2, and the transistor TR2 cannot operate. However, the comparison input voltage ■ is the reference voltage v3.
Once higher, transistor TR2 conducts and its output signal is supplied via diode D to the reset R2 terminal of relay RL l and to the reset R2 terminal of relay R,2, putting both relays RL l and RL2 in the reset state. do. This is exactly the same result as selecting the same-size selection push button SWl, and therefore the variable magnification device is driven to make a same-size copy.

If the copying machine continues in the magnification copying state as described above for a predetermined time interval or longer, the automatic magnification return control circuit operates and the copying machine automatically returns to the same-magnification copying state.

The predetermined time interval can be arbitrarily determined by changing the time constant by changing the values of variable resistor vR and capacitor C1 of timer circuit (2).

If the magnification copying operation or magnification selection operation is performed again within the set time interval, the magnification restoration operation is interrupted as follows.

When the next magnification copying cycle begins, relay contact a-1 is opened and the input signal to timer circuit m is cut off.

After the completion of the previous copying cycle, the capacitor C1 is charged and the voltage V at point P2 gradually rises, but as soon as the input signal to the timer circuit m is cut off, the charge that had been charged in the capacitor C1 until then is transferred to the diode. Discharge occurs through a closed circuit including D2 and resistor R4, but if the discharge occurs before voltage V becomes higher than voltage V3, comparator C does not operate and no output signal is output to output terminal B of timer circuit m. That is, the timer circuit m does not operate until the input signal is again supplied to its input terminal A. As a result, the transistor TR2 is not conductive and there is no magnification return signal to the magnification selection circuit II, so the magnification copying state is maintained as it is. .

Furthermore, when the magnification selection operation is performed within the set time interval, the variable magnification drive signal is applied to point P, so the transistor TRI is cut off and the input signal to the timer circuit ■ is cut off, which is exactly the same as described above. For the reason, magnification selection circuit II
No magnification return signal is generated and the magnification copy state is maintained as is.

On the other hand, in FIGS. 2 and 3, reference numeral 1 denotes a transparent glass original table, which reciprocates in the direction of the arrow during copying. The image on the document placed on the document table L is displayed by the document illumination lamp 2.
It is illuminated by a focusing light transmitter (trade name, SELFOC lens) 3, rotates in the direction of the arrow in synchronization with the movement of the document, and condenses onto the photosensitive drum 5, which has been fully charged in advance by a charging electrode 4. An electrostatic image is formed on the photosensitive drum 5.The formed electrostatic image is transferred onto a magnet roller 8 provided in a developing/cleaning device 7 of a process unit 6 (the area surrounded by a dashed line). Developed by a magnetic brush formed by magnetic toner.A one-component developer is sealed in the developing/cleaning section 7 in advance.The recording paper P is fed one by one by a paper feed roller 9, The image on the photosensitive drum is transferred by the transfer electrode 11 to the photosensitive drum 5 via the register roller 10, and is separated from the photosensitive drum 5 by the separation electrode 12, proceeds along the guide plate 13, and then passes through the fixing roller 14. After passing through the paper ejection roller 15, the completed recorded material is ejected out of the machine.The drum surface, which has completed the image transfer, continues to advance as it is, but the copying machine enters the cleaning operation in the !$2 mode.In other words, The entire surface is not charged by the charging electrode 4 and the image exposure by the focusing light transmitter 3 is not performed, and the static elimination lamp 16 is turned on, and the residual charge on the photosensitive drum 5 is erased by the light.The residual charge is erased and the photosensitive drum 5 is exposed. drum 5
The toner that has lost its attraction to the surface is caught by a magnetic brush formed on the magnet/troller 8L and is developed and cleaned. When the photosensitive drum 5 rotates once and the cleaning of its surface is completed, the operation of the copying machine returns to the first mode.
Image formation is again carried out by the process of charging the entire surface, exposing it to light, and developing it.

In the copying machine of this embodiment, the photosensitive drum 5 as an electrostatic image carrier, the developing/cleaning device, the charging electrode 4, and the static elimination lamp IB are integrated into a process unit ( ) 6, which is installed in the main body of the copying machine. The process unit 6, which is slidably and removably mounted on the rail μs holding member 17, 18, is fixed in a predetermined position in use by a locking means (not shown). Power and electric power are supplied to the process unit 6 through terminals and a power transmission mechanism (not shown in the figure) provided on the back side of the unit, that is, in the direction of the arrow in the partial cross-sectional perspective view of the process unit shown in FIG. It is done.

When replacing the process unit 6, by opening the front door of the main body and releasing the lock, the process unit 6 can be easily removed by pulling it out toward the front in the paper of FIG.

Further, in the variable magnification copying machine of the present invention, a switch SW is fixedly installed which is pressed by the end portion 6a of the process unit 6 when the process unit 6 is mounted on the copying machine main body. 6 is removed from the copying machine body, the switch SW is automatically closed to connect the power supply outlet (not shown), and the voltage at the same level as +VB is applied to point P1 of the automatic magnification return control circuit described above. is applied, thereby stopping the magnification return operation.

That is, according to the variable magnification copying machine of the present invention, when a plurality of process kits 6 containing toner of each single color are prepared and multicolor copying is to be performed with the same variable magnification, it is necessary to replace the process kits. Since the operation of the automatic magnification return control circuit is interrupted during the copy cycle, there is no switching from the variable magnification mode to the same magnification mode during the copy cycle. This makes it possible to complete multicolor copies.

Note that the means for stopping the operation of the automatic magnification return control circuit of a copying machine by escaping the process unit 6 of the present invention is not only shown in this embodiment but also applicable to a type of variable-magnification copying machine in which the copying machine main body can be divided into upper and lower halves. It is possible to do so.

〔Effect of the invention〕

The present invention maintains a predetermined variable magnification mode at all times during the copy cycle, not only for monochrome copying using a single process unit but also for multicolor copying performed by exchanging multiple process units. An extremely useful variable magnification copying machine that returns to the same magnification mode has now been provided.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram for automatic magnification return control, Fig. 2 is a main body configuration diagram of the variable magnification copying machine of the present invention, and Fig. 3 is a perspective view of its process kit. Magnification return control circuit II...
...... Magnification selection circuit ■ ...... Timer circuit 4 ...... Charged electrode 5 ...
...Photoreceptor drum 6...Process unit 7...Development and cleaning device 8
......Magnetic roller 16...
...Static elimination lamp 17.18 ...Rail holding member SW ...Switch agent Patent attorney No 1) Father-in-law Figure 1

Claims (2)

[Claims] (1) In a copying mode where a process unit having at least a drum can be inserted into and removed from the main body, the copy magnification setting section converts the copy magnification to the same magnification mode and the variable magnification mode, and the variable magnification mode changes after a certain period of time after copying is completed. 1. A variable-magnification copying machine comprising: an automatic return means for returning to a magnification mode for returning to a magnification mode, and the automatic return means to an equal-magnification mode is inactivated when the process unit is removed from the main body. (2) The variable-magnification copying machine according to claim 1, wherein the main body consists of an upper and lower main body and can be divided into two parts.