JPH07101279B2 - Original illumination device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash lamp type document illuminating device, and more specifically, to detect a breakage of a contact glass or an open / closed state of a protective cover to issue an alarm or a warning. In particular, it relates to a document illuminating device with improved safety.

[Prior art]

The flash lamp type document illuminating device in the electrophotographic apparatus has a trigger wire provided on the outer periphery of the flash lamp, and by applying a predetermined high voltage to the trigger wire, the lighting of the flash lamp is activated. ing. For this reason, the flash lamp is surrounded by a cover to ensure safety.

On the other hand, when the flash lamp is replaced or during maintenance, the cover is opened so that it can be detected, or (and) damage to the contact glass can be detected, and the power can be automatically cut off based on the detection to cause electric shock. Was trying to avoid the danger of.

However, even if the power supply to the device is stopped, the main capacitor for light emission of the flash lamp is installed in the device, and the main capacitor is charged with high voltage. At times, when the main body device cover is opened for replacement processing, or when the contact glass is damaged, there is a risk of contact with the high-voltage portion in the device and electric shock.

〔Purpose〕

The present invention has been made in view of these drawbacks,
It is an object of the present invention to provide an original illuminating device that prevents an electric shock accident due to opening of a protective cover for lamp replacement or contact with a high-voltage portion exposed due to damage of a contact glass.

〔Constitution〕

In order to achieve this purpose, it is detected that the charging voltage of the capacitor is more than an arbitrary voltage, and the contact glass is damaged or (and) the protective cover is open, and accordingly a warning such as a warning or display is issued. It is something to do.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 and 2 are explanatory views showing the structure of a document illuminating device used in the electrophotographic apparatus according to the present invention.

A flash lamp 1 that irradiates the original 4 with light and a lower base member 9 that is fixed below the flash lamp 1 are reflected by the light to the original 4 side to prevent direct irradiation of the original 4 with light. The reflecting mirror 2 for guiding and the flash lamp 1 for reflecting the light emitted on the opposite side to the reflecting mirror 2 to the reflecting mirror 2 side are arranged around the flash lamp 1, and a concentric reflector 5 is arranged to improve the illumination efficiency. I am raising.

The contact glass 3 on which the original 4 is placed is fixed to the upper base member 7 by a fixing member 6, and the lower portion of the contact glass 3 is adjusted so as to be constantly in contact with the lower surface of the contact glass 3 and the upper portion. A switch 8 fixed to a base member 7 by a bracket (not shown) or the like is provided to constantly detect damage to the contact glass 3.

An opening 10 is provided between the upper base member 7 and the lower base member 9 for holding the reflecting mirror 2 for maintenance and inspection of the inside of the flash lamp 1 and the like.
10 is closed by a protective cover 11, and the open / close detection switch 12 fixed to the lower base member 9 is a protective cover.
The open / closed state of 11 is always detected.

Further, an outer cover 13 for protecting the apparatus body is provided outside the protective cover 11 and the upper base member 7.

In addition, as shown in FIG. 2, two sides adjacent to the upper base member 7 are fixed to the contact glass 3 by the fixing member 6, and the fixing member 6 indicates the size of the original 4 and the placement position. It is printed. The switch 8 is arranged below the free end corner portion 14 of the contact glass 3 to detect damage to the contact glass 3.

The flash lamp 1 is held by a lamp holder 16 and fixed to a lower base member 9. Around the flash lamp 1, a trigger wire 17 as a trigger means for activating the light emission of the flash lamp 1 is encircled, and the trigger wire 17 is the flash wire 1.
Power is drawn from both ends of and connected to a trigger unit (not shown).

Furthermore, since a nickel wire is used for the trigger wire 17 and the metal part is exposed, a high voltage is applied to the trigger wire 17 when the flash lamp 1 is turned on, which is extremely dangerous. Therefore, the protective cover 11 is attached. There is something.

FIG. 3 is an explanatory diagram of the control circuit in the present invention.

Power supply 20 that supplies drive energy to the inside of the device, and power supply 20
Relay 18 (normally closed contacts 19 _a , 19 _b) that switches the supply of the power from the charging circuit to the warning circuit or vice versa.
And 39 _a , 39 _b ), a rectifying circuit 50 and the rectifying circuit 5
Capacitor 51 that removes pulsation from the voltage waveform obtained at 0
Rectifying and smoothing circuit 21 composed of a DC-DC converter 2 as a power conversion circuit for converting a DC input voltage into an arbitrary DC voltage
2 and are provided.

The DC-DC converter 22 has a resistor 30 for generating a charging detection voltage V _1.
A main capacitor 24, a flash lamp 1 which is made to emit light by the main capacitor 24, and a trigger circuit 25 for activating a trigger wire 17 provided around the flash lamp 1 in response to a trigger signal from a control unit 23 described later. Are connected.

Further, a coil 52 is installed between the main capacitor 24 and the flash lamp 1 in order to control the discharge time of the flash lamp 1.

A transformer 26 _a next transforms the power from the power source 20 as a charging voltage detection circuit, and the same rectifying smoothing circuit 27, three-terminal regulator 28 and _a, resistors for producing the reference voltage V ₀ 29
and _a, 29 _b, a diode 34 for holding the charge detection voltages V ₁ to a peak voltage, the capacitor 35 is provided.

Further, the comparator 31 for comparing the reference voltage V ₀ and the charge detection voltage V ₁ and the ON state by the operation of the comparator 31
Then, the transistor 32 that turns on the relay 33, the photocoupler 36 that turns on upon receiving a trigger signal from the control unit 23, and the transistor 37 that operates when the photocoupler 36 turns on,
A normally open contact 38 is arranged between the switch 8 and the switch 12 connected in parallel, and between the switch 8 and the switch 12 and the relay 18.

Next, as a warning circuit, a transformer 26 _b for transforming the power from the relay 18, a rectifying / smoothing circuit 40 similar to the above, a three-terminal regulator 28 _b, and a buzzer 41 and an alarm for the rectifying / smoothing circuit 40 An indicator lamp 42 for notifying "danger" or "caution" is connected.

The operation of the above configuration will be described with reference to the time chart of FIG.

Normally, the switches 8 and 12 are in the OFF state when the contact glass is not damaged and the protective cover is not opened, and thus the relay 18 is also in the OFF state. Power is supplied from the power supply 20 to the DC-DC converter 22 via the rectifying / smoothing circuit 21 by the normally closed contacts 19 _a and 19 _b of the relay 18.

During the copying operation, the main capacitor 24 is charged by the charging signal from the control unit 23 to the DC-DC converter 22, and then the trigger circuit 25 is activated by the trigger signal from the control unit 23, and the trigger wire 17 is used to discharge. The flash lamp 1 emits light.

On the other hand, the direct current is supplied via a transformer 26 _a and three-terminal regulator 28 _a for the charging voltage detection circuit. Further, the resistors 29 _a and 29 _b generate a reference voltage V ₀ , and when the main capacitor 24 is charged, a good charge detection voltage V ₁ is generated in the resistor 30.

The comparator 31 compares the reference voltage V ₀ with the charge detection voltage V ₁ , and compares the reference voltage V ₀ with the charge detection voltage V ₁
When exceeds, the output becomes High, the transistor 32 turns on, and the relay 33 operates.

In this case, the charge detection voltage V ₁ is held at the peak voltage by the diode 34 and the capacitor 35.

The photo coupler 38 is turned on by the trigger signal from the control unit 23.
As a result, the transistor 37 is activated, the capacitor 35 is discharged, and the peak hold is released. By this release, the output of the comparator 31 becomes Low, and as a result, the transistor 32 is turned off and the relay 33 is released.

Therefore, when the flash lamp is turned on, the relay 33 repeats the opening / closing operation. Further, when the switches 8 and 12 are both OFF, the normally open contact 38 of the relay 33 does not operate the relay 18 even if the normally open contact 38 is turned ON and OFF.

Next, when the contact glass 1 is damaged or (and) the protective cover is in an open state, a charging signal is emitted due to malfunction or noise to the control unit 23,
When the main capacitor 24 is charged and the charge detection voltage V ₁ becomes higher than the reference voltage V ₀ , the relay 33 operates. At this time, since the switch 8 and / or the switch 12 is ON, the normally open contact 38 of the relay 33 is closed, so that the relay 18 operates. As a result, the relay
The 18 normally closed contacts 19 _a and 19 _b are released, and the supply of power to the charging circuit is stopped.

On the contrary, the normally closed contacts 39 _a and 39 _b of the relay 18 are closed, and as a result, power is supplied to the transformer 26 _b , and the buzzer 41 and the indicator lamp 42 are turned on via the rectifying / smoothing circuit 40 and the three-terminal regulator 28 _b. , A warning is given to the operator.

The normally open contact 38 of the relay 33 is closed even if the contact glass 1 is damaged or (and) the protective cover is opened while the main capacitor 24 is being charged,
Furthermore, since the switch 8 or (and) the switch 12 is ON, the relay 18 operates similarly, and as a result, the relay 18
Since 18 normally closed contacts 19 _a and 19 _b are released,
The power supply to the charging circuit is stopped.

On the contrary, the normally closed contacts 39 _a and 39 _b of the relay 18 are closed, and as a result, power is supplied to the transformer 26 _b , and the buzzer 41 and the indicator lamp 42 are turned on via the rectifying / smoothing circuit 40 and the three-terminal regulator 28 _b. , A warning is given to the operator.

When the buzzer 41 and the indicator lamp 42 are turned on, the main capacitor 2
Since 4 is spontaneously discharged, the warning can be stopped by outputting a release signal (pulse signal) from the control unit 23 after a sufficient time for discharging has elapsed.

Further, in order to ensure reliable operation of the charging voltage detection circuit and the warning circuit so as not to stop when the main switch is turned off, another power source (for example, a lithium battery) may be installed.

Part (I) of FIG. 4 means the operation of each part in the normal copy mode.

That is, charging is started by the charging signal and the flash lamp 1 emits light by the trigger signal. The relay 33 is turned on when the charging detection voltage V ₁ becomes higher than the reference voltage V ₀ , and turned off by a trigger signal from the control unit 23.

Part (II) of FIG. 4 shows that the relay 18 does not operate and the warning circuit does not operate even if the switches 8 and 12 are turned on during non-charging.

The part (III) in FIG. 4 means the operation of each part when the contact glass 3 is damaged or / and the charging is started when the protective cover 11 is opened.

That is, when the reference voltage is reached after the start of charging, the relay 33 and
18 is turned on. When the switch 8 and / or the switch 12 is opened, the relay 18 is turned off and the warning is released, but the relay 33 is not turned off and is in the hold state.

However, since the charging operation is stopped when the relay 18 is turned on, the actual charging detection voltage decreases as the main capacitor 23 spontaneously discharges, as indicated by the chain double-dashed line 43.
When the charge detection voltage is checked again by the release signal 44 from the control unit 23, the charge detection voltage V ₁ is lower than the reference voltage V _0, so that the relay 33 is released at that time.

The part (IV) in FIG. 4 means the operation of each part when the contact glass 3 is damaged or (and) the protective cover 11 is opened after charging.

Switch 8 or (and) because relay 33 is ON
The relay 18 is turned on at the same time when the switch 12 is turned on, and a warning is issued.

Even if the release signal 45 is issued from the control unit 23, the actual charge detection voltage V ₁ decreases as shown by 46, so that the relay 33 is not released when the reference voltage V ₀ or higher. Has become. Therefore, even if the release signal 45 is issued, the relay 33 is not released unless the main capacitor 23 is sufficiently discharged. At this time, if the protective cover 11 or the like is opened, the relay 33 is released.
18 turns on and issues a warning.

In addition, in this embodiment, since the switch 8 is arranged below the corner portion of the free end of the contact glass 3, when the contact glass 3 is damaged, the broken pieces are fixed.
Even if they are sandwiched between the upper base member 7 and remain, the fragments of the free end portion 14 are not pressed, so that the switch 8 operates reliably.

If the broken pieces of the contact glass 3 remain with the switch 8 held down (for example, the broken line in FIG. 2).
In 15), since the switch 8 is arranged on the flash lamp 1 side, in general, the operator hardly touches the lamp part by inserting his / her hand toward the fracture surface. The arrangement on the free end side 14 of the contact glass 3 is very effective in terms of safety.

(Effect) As described above, according to the document illumination device of the present invention, it is detected that the charging voltage of the capacitor is equal to or higher than an arbitrary voltage, the contact glass is broken, and / or the protective cover is open, and Since a warning such as a squeezing alarm and a display is given, it is possible to prevent an electric shock accident caused by opening the protective cover for lamp replacement or contact with the exposed high-voltage part due to damage of the contact glass.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a document illuminating device according to the present invention, FIG. 2 is a partially broken perspective view of a document illuminating device according to the present invention, and FIG. 3 is an operation circuit of the document illuminating device according to the present invention. FIG. 4 is an explanatory diagram, and FIG. 4 is a time chart showing the operation of each part of the document illuminating device according to the present invention. Explanation of code 1 …… Flash lamp 3 …… Contact glass, 4 …… Original 8,12 …… Switch 17 …… Trigger wire, 18 …… Relay 23 …… Control section, 24 …… Main capacitor 25 …… Trigger circuit 31 …… Comparator, 36 …… Photo coupler 41 …… Buzzer, 42 …… Indicator lamp

Claims (2)

[Claims] 1. A document illuminating device which irradiates a document with light emitted from a flash lamp having a trigger wire for urging and exposes a photoconductor by the reflected light, and detects damage to a contact glass on which the document is placed. A glass detecting means, a cover detecting means for detecting an open / closed state of a protective cover for protecting the lamp, and a voltage detecting means for detecting a potential of a capacitor for causing the lamp to emit light are provided. A document illuminating device characterized in that warning means such as an alarm and a display are activated based on a signal from the glass detection means or / and the cover detection means on the premise of signal input. 2. The document illuminating apparatus according to claim 1, wherein the warning means is activated and power supply to the capacitor is stopped.