JPS6084554A - Electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To prevent rise of temp. of members, such as contact glass, near an exposure lamp, by controlling the turn-off time of the lamp at the time of successive copying in accordance with the change of power feed. CONSTITUTION:The lighting time of an exposure lamp is made constant, and it can be set to a prescribed time in accordance with copying magnification, and the turn-off time of the lamp can be changed in successive copying. Such an electrophotographic copying machine is provided with a power feed setting means (A) for setting an amt. of power to be fed to the lamp, a power feed judging means (B) for judging an amt. of power to be fed set with the means (A), and a lamp turn-off time deciding means (C) for deciding the turn-off of the lamp in successive copying on the basis of the judged result by the means (B).

Description

[Detailed description of the invention] Technical field The present invention relates to an electronic copying machine.

2. Description of the Related Art As a prior art electronic copying machine, one is known in which the power supplied to an exposure lamp of an exposure device can be adjusted in multiple stages.

However, this electronic copying machine has a drawback in that when a large amount of power is supplied to the exposure lamp of the exposure device, the temperature of members such as contact glass near the exposure lamp increases too much during continuous copying.

Purpose The purpose of the present invention is to prevent the temperature of members such as contact glass near the exposure lamp from rising too much by adjusting the turn-off time of the exposure lamp during continuous copying in response to changes in the power supplied to the exposure lamp. The object of the present invention is to provide an electronic copying machine that can prevent such problems.

composition The configuration of the present invention will be explained based on illustrated embodiments.

The present invention makes the lighting time of the host lamp constant, or
In an electronic copying machine that can set a predetermined time depending on the copying magnification and also change the exposure lamp turn-off time during continuous copying, the power supplied to the exposure lamp is set as shown in Figure 1. a supply power setting means A for determining the power supply setting means A; a supply power determination means B for determining the magnitude of the supply power set by the supply power setting means AIC; and an exposure lamp during continuous copying based on the determination result of the supply power determination means B. and a lights-out time determining means C for determining the lights-out time.

Next, specific examples of the present invention will be explained based on FIGS. 2 to 6.

FIG. 2 schematically shows an example of an electronic copying machine according to the present invention.

In FIG. 2, reference numeral 1 indicates a contact glass. A document 2 is placed on the contact glass 1 . An original pressing plate 4 for pressing the original 2 onto the contact glass 1 is provided on the exterior plate 3 near the contact glass 1 so as to be openable and closable.

An exposure device 5 is arranged below the contact glass 1. A drum-shaped photoreceptor 6 is arranged below the exposure device 5 . This photoreceptor 6 is rotated at a predetermined circumferential speed in the direction of arrow 8 during copying.

The photoreceptor 6 is surrounded by a charging device 7, a developing device 8, a transfer device 9, a transfer paper supply device 10, a fixing device @ 11, a transfer paper conveyance device 12, a cleaning device 13, and a static eliminator 1.
4 etc. are arranged at predetermined positions.

The exposure device 5 includes an exposure lamp 5a that illuminates the original 2;
Reflector 5b, first mirror 5c, second mirror 5d, zoom lens 5e, third mirror 5f and fourth mirror 5g
It consists of The exposure lamp 5a1, the reflector 5b and the first mirror 5C are moved in the direction indicated by the arrow, and the second mirror 5d is moved in the same direction as these at a speed ratio of 2:1, thereby forming a slit shape from the original 2. The photoreceptor 6 is irradiated with image light. The speed of the exposure lamp 5as') collector 5b and first mirror 5C in the direction of the arrow is determined to be a predetermined ratio to the circumferential speed of the photoconductor 6 according to the copying magnification, and the circumferential speed of the photoconductor 6 is Since the exposure lamp 5a is constant, the lighting time of the exposure lamp 5a is set to a predetermined time depending on the copying magnification.

After the photoreceptor 6 is irradiated with image light from the entire surface of the document 2, the exposure lamp 5a stops in an extinguished state, moves in the direction opposite to the direction indicated by the arrow, and returns to the standby position.

An operation panel 15 is provided on the upper surface of the exterior plate 3. As shown in FIG. 3, this operation panel 15 includes a magnification setting switch 16 for setting the copy magnification, a power setting switch 17 for setting the power supplied to the exposure lamp 5a, and the number of copies to be made. A number-of-copies setting switch 18, a start switch 19, a stop switch 20, etc. are provided for this purpose.

As shown in FIGS. 3 and 4, the magnification setting switch 16 includes, for example, four key switches. Information as to which of the magnification setting switches 16 is turned on is given to the input port of the micro convenience store 21. The power setting switch 17 includes, for example, eight key switches. Information as to which of these power setting switches 17 is turned on is given to the input port of the microcomputer 21. The number-of-copies setting switch 18 consists of ten key switches. Information about which of these copy number setting switches 18 is turned on or in what order a plurality of copy number setting switches 18 are turned on is provided to the input port of the microcomputer 21. It will be done. Further, information indicating that the start switch 19 and stop switch 20 have been turned on is given to the input port of the microcomputer 21.

The output port of the microcomputer 21 is a resistor r1
is connected to the base of transistor 220 via.

A light emitting diode 23a of a 7-opto coupler 23 is connected to the collector of this transistor 22. The exposure lamp 5a and the triac 24 are connected in series to an AC power source 25.

A DC power supply 26 is connected between the power supply terminal of the triac 24 and the emitter of the phototransistor 23b of the photocoupler 23. The phototransistor 23b
The collector of is connected to the gate terminal of the triac 24 via a resistor r2. The above triac 24 has
When the phototransistor 23b is in the ON state, the DC power supply 2
A gate current flows from the phototransistor 6 through the phototransistor 23b.

During the lighting time of the exposure lamp 5a, a pulsed output signal consisting of an ON signal and an OFF signal is applied from the output port of the microcomputer 21 to the base of the transistor 22. When an ON signal is applied from the output port of the microcomputer 21 to the base of the transistor 22, the transistor 22 is turned on, a current flows through the photocoupler 230 and the light emitting diode 23aK, the light emitting diode 23a emits light, and the phototransistor 23b is turned on. Then, a gate current flows from the DC power supply 26 to the triac 24 and the triac 24 is turned on, so that current is supplied from the AC power supply 25 to the exposure lamp 5a and the exposure lamp 5a is turned on. Each of the above power setting switches 17 In response to an ON signal from another device, the microcomputer 21 controls the exposure lamp 5.
By changing the phase of the output signal from the output boat during the lighting time a, the energization ratio of the triac 24 is changed, and the magnitude of the power supplied to the exposure lamp 5a is changed in multiple stages.

The input section of the power supply setting means A includes a circuit including a power setting switch 17, and as shown in FIG.
A variable resistor r3 and a resistor r4, whose resistance value can be changed by operating a knob 28 with fingers, are connected in series between the terminal 27 to which a predetermined voltage is applied by a DC power source and the ground. The voltage at the connection point between r3 and resistor r4 is transmitted to the microcomputer 2 via the A/D conversion circuit 29.
Knob 2 that is given to 1 and changes the resistance value of variable resistor r3
8 may be configured to provide the microcomputer 21 with information for setting the power supplied to the exposure lamp 5a.

Next, an example of the operation of the electronic copying machine configured as described above will be explained.

The start switch 19 is turned on, one of the magnification setting switches 16 is turned on, one of the power setting switches 17 is turned on, and one or more copy number setting switches 18 are turned on. Then, the operation of the electronic copying machine is started according to the four-gram procedure stored in the ROM of the microcomputer 21 and shown in the flowchart of FIG.

First, as shown in FIG. 6, in step (2), the lighting time of the exposure lamp 5a is set to a predetermined time based on information from the magnification setting switch 16. When changing the copying magnification by turning on one of the magnification setting switches 16 in step (3), an output signal is given from the output port of the microcomputer 21 to the optical member driving means (not shown), and the exposure The position and focal length of the zoom lens 5e of the device 5 and the position of the third mirror 5f are changed.

Next, in step (2), the magnitude of the power to be supplied to the exposure lamp 5a is set based on the information from the power setting switch 17, and the set power value P is stored in the RAMK.

Next, in step (2), based on the information from the number of copies setting switch 18, it is determined whether the number of copies N is 2 or more.
That is, it is determined whether or not it is N22.

If it is determined in step ■ that it is N22, step ■
The set power value P and the reference power value P stored in the ROM
1 and it is determined whether P≦P1.

If it is determined in step ■ that P≦P1 is not satisfied, then in step ■ the set power value P is compared with a reference power value P2 (P2>Pi) stored in the ROM, and it is determined whether P≦P2. be done.

If it is determined in step ■ that P≦P1, step ■
Then, the turn-off time t of the exposure lamp 5a during continuous copying is determined to be the time t1. When it is determined that P≦P2 in step (ji), the turn-off time t of the exposure lamp 5a is executed.
is determined at time t2 (t2)tl). If it is determined in step (2) that P≦P2 is not satisfied, then in step (2) the extinguishing time t of the exposure lamp 5a is determined to be the time ta(ta)tz).

Next, in step (2), the image of the original document 2 is copied. Next, in step [phase], it is determined whether or not copying is complete. If step [phase] determines that copying is not completed, step ■
Then the next copy is made. When it is determined in step [phase] that copying is complete, the copying operation is stopped.

The set power value P is compared with a reference power value of 3 or more to determine whether it is large or small, and based on this determination result, the extinguishing time type of the exposure lamp 5a during continuous copying is determined in double V stages. Good too.

The present invention is also applicable to an electronic copying machine that does not have a means for changing the copying magnification, ie, an electronic copying machine in which the lighting time of the exposure lamp is constant.

Effects The electronic copying machine of the present invention is a supply type to the exposure lamp.By adjusting the extinguishing time of the exposure lamp during continuous copying in response to changes in force, the temperature of members such as contact glass near the exposure lamp can be reduced. This can prevent it from rising too high.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a partially cutaway front view showing an outline of the configuration of an electronic copying machine as an embodiment of the present invention, and FIG. 3 is an operation panel of the same electronic copying machine. FIG. 4 is an electric circuit diagram showing an electric circuit according to an embodiment of the present invention, FIG. 5 is an electric circuit diagram showing main parts of another embodiment of the same electric circuit, and FIG. is a flowchart showing an example of a program for operating the electronic copying machine of the present invention. 5... Exposure device, 5a... Exposure lamp, 6... Photoreceptor, 17... Power setting switch, 21... Microcomputer

Claims (1)

[Claims] In an electronic copying machine, the lighting time of the exposure lamp can be fixed or set to a predetermined time depending on the copying magnification, and the lighting time of the exposure lamp can be changed during continuous copying. A supply power setting means for setting the supply power, a supply power determination means for determining the magnitude of the supply power set by the supply power setting means, and an exposure lamp during continuous copying based on the determination result of the supply power determination means. 1. An electronic copying machine comprising: a light-off time determining means for determining a light-off time.