JPS61129673A - Lighting check system of flash lamp - Google Patents

Abstract

PURPOSE:To discriminate accurately lighting of a flash lamp to prevent misflash by providing the first means which detects a prescribed high voltage to detect a charging completion signal and the second means which detects a low voltage after discharging completion. CONSTITUTION:AC 200V is inputted to a high-voltage rectifying circuit 9 through a switching circuit 7 and a high voltage transformer T1 to generate a high voltage, and a capacitor C1 is charged thereby. A charging control circuit 8 turns on the switching circuit 7 by a charging signal CHON and turns off the switching circuit 7 when detecting a prescribed high voltage by resistances R3 and R4. The charging voltage of the capacitor C1 is detected by resistances R1, R2, and R7, and a charging completion signal is outputted if a prescribed high voltage is obtained by a comparator 10. The voltage of the capacitor C1 just after lighting of a lamp 4 due to conduction of an SCR is detected by resistances R1, R2, and R7 and is compared with a prescribed value by a comparator 12 to confirm the discharging completion. Thus, the misflash of the lamp 4 is detected accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a flash fixing device that thermally fixes toner using flash energy from a flash lamp.

In particular, the present invention relates to a flash lamp lighting check method for accurately checking the lighting state of a flash lamp used in the flash fixing device.

In general, a flash fixing device uses a developing device 1 to place toner 2 on a recording medium 3 to visualize an electrostatic latent image, as shown in FIG. The toner 2 is guided to a fixing section 6 consisting of a toner 5 and a flash lamp 4 is caused to emit flash light, and the toner 2 is fixed on the recording medium 3 by the flash energy.

The heat fixing method using the flash lamp 4 as described above does not require preheating and there is no risk of the recording paper catching fire.1
It has an equivalent feature of simple mechanism.

However, if a fixation error occurs due to a flash error,
Because it is not possible to tell whether or not there is a fixing problem just by looking at the print result, 1. For example, if printing was performed normally, but after erasing the print data, you notice that there is a fixing problem.
Calculations must be performed to obtain print data again, which is a huge waste of time.

Therefore, it is necessary to check the flash.

It is desired to put into practical use a method that can perform such a flash check simply, accurately, and reliably.

[Conventional technology]

FIG. 4 is a block diagram showing a conventional flash lamp lighting check method, and FIG. 5 is a conventional flash miss check timing diagram.

The commercial power supply A, C 200V is switched by the switching circuit 7, boosted to a predetermined high voltage by the high voltage transformer T1, and rectified by the high voltage rectifier circuit 9 to charge the charging capacitor C1 of the flash lamp 4 with a constant current. . Furthermore, the fifth
Figure (11) shows the charging and discharging status of the capacitor C1.

The capacitor C1 is charged until a certain reference voltage vF is reached. Further, this charging operation is controlled by a charging control circuit 8 that receives a charging signal CHON.

That is, the charging control circuit 8 starts charging and detects that the charging voltage to the capacitor C1 reaches a certain reference voltage VF by the voltage drawn between the resistors R3 and R4, and controls the switching circuit 7. A, C Cut off the 200V input and stop the charging operation.

On the other hand, when the charging voltage exceeds the voltage v1, the conveyor circuit 10
A charging completion signal CHOK is output from. That is, a charging voltage is drawn into the conveyor circuit 10 from between the resistors R1 and R2, and compared with a reference voltage vI in the conveyor circuit 10. If they match, a charging completion signal CHOK is output.

When the trigger signal TRG is applied in this state, the thyristor SCR is turned on, and the voltage charged in the capacitor c2 is boosted by the trigger coil T2.

The voltage is supplied to the trigger coil T2 of the flash lamp 4, and the flash lamp 4 is turned on.

The moment flash lamp 4 lights up, the current coil CT
(indicated by the dotted line ○) is detected by the current detection circuit 11, and the current detection circuit 11 transmits the current detection signal FLSI ((i.e., flash lamp lighting confirmation signal) to a control unit (not shown). Output to.

Note that the check signal CHEFF shown in FIG. 5 is the charging signal CH.
This is a signal that is set when the charge completion signal C) IOK is "high" at the falling edge of ON, that is, at the end of the charging operation. Further, the trigger signal TRG is applied to the current detection signal FL.
When SH is detected, the check signal CI (EFF) is reset.

Further, the flush miss signal PLMIS is not set when the check signal CHEFF is "low", that is, reset, during the period of the check timing CH5TB, indicating that a flush operation has been performed on the perch; When CHEFF is "high", that is, when the signal S11 is not detected, the signal FLMIS is set and it is determined that a flash miss has occurred.

It should be noted that these signals include the charging signal CHON, the trigger signal TRG, the check signal CHEFF, the check timing Cll5TB, the charge completion signal C)IOK, and the current detection signal FLSH.

It is assumed that the flash miss signal FLMIS ((L) in FIG. 5 indicates "low") and the like are generated, outputted, and received by a control section (not shown).

[Problem that the invention seeks to solve]

In the above method, the current change obtained from the current coil CT is detected by the current detection circuit 11.
The current detection signals pt and so outputted by 1 are current pulse signals, and the pulse width of this current pulse signal is several hundred μs.
It is difficult to distinguish it from noise because it is narrow and unstable.

Therefore, there is a problem in that the control section (not shown) makes an erroneous detection as shown in FIG.

[Means for solving problems]

The present invention is a novel infrastructure that solves the above problems.

The purpose of this method is to realize a Schlump lighting check method, and the problem is that the first detection means detects a predetermined voltage as a charge completion signal, and the second detection means detects another predetermined voltage as a discharge completion signal. The problem is solved by the flash lamp lighting check method according to the present invention, which includes a detection means and checks the lighting state of the flash lamp based on the detection results of both the detection means.

[Effect]

In other words, the charging voltage after flashing the flash lamp is:
By paying attention to the fact that the value decreases to almost zero and checking the signal indicating the completion of charging before flashing and the signal indicating completion of discharging after flashing, the lighting status of the flash lamp can be confirmed. This makes it possible to perform this reliably with a simple circuit configuration.

〔Example〕

The main points of the present invention will be explained in detail below with reference to embodiments shown in FIGS. 1 and 2.

FIG. 1 is a block diagram showing an embodiment of the flash lamp lighting check method according to the present invention, and FIG. 2 is a flash mischeck timing diagram in the flash lamp lighting check method according to the present invention.

Next, the operation of the two embodiments will be explained, focusing mainly on the parts related to the present invention. The same reference numerals indicate the same objects throughout the figures.

The discharge completion signal DCHOK of this embodiment is the capacitor CI
This is a signal obtained when the charging voltage of the flash lamp is turned on, that is, when it drops to a predetermined voltage (e.g., equivalent to several volts) after the start of discharge, and its reference voltage is v2.

That is, the conveyor circuit 12 compares the voltage drawn between the resistors R7 and R2 with the reference voltage v2, and if they match, sends the discharge completion signal DCHOK to the control section (not shown), and outputs it from the conveyor circuit 10. Charging completion signal CHO
The lighting state of the flash lamp is checked using the discharge completion signal DCHOK and the discharge completion signal DCHOK.

The method of setting the check signal CHEFF shown in FIG. 2 is to set the charging completion signal C when the charging signal Cl0N falls.
II OK and discharge completion signal DCHOK are both “high”
It is set when the check timing CHSTB falls, and is reset when the check timing CHSTB falls.

Then, during this check timing CH5TB,
Check signal CHEFF is “high”, discharge completion signal DC
Check that HOK is "low".

If the check signal CHEFF is “
If the discharge completion signal DCI (OK is "high"), the flash miss signal FLMIS is set and it is determined that a flash miss has occurred.

〔Effect of the invention〕

According to the present invention as described above, there is an effect that accurate flash lamp lighting check can be performed with a simple circuit configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a flash lamp lighting check method according to the present invention. FIG. 2 is a timing diagram of the Franchemise check in the flash lamp lighting check method according to the present invention. FIG. 3 is a schematic diagram of a flash fixing device. FIG. 4 is a block diagram showing a conventional flash lamp lighting check method. FIG. 5 is a conventional flash miss check timing diagram. are shown respectively. In fig. 1 is the developing machine, 2 is the toner. 3 is a recording body, 4 is a Fra Nosurump. 5 is a reflector, 6 is a fixing section. 7 is a switching circuit, and 8 is a charging control circuit. 9 is a high voltage rectifier circuit, 10.12 is a conveyor circuit. 11 is a current detection circuit. are shown respectively.

Claims (1)

[Claims] A flash fixing device comprising: a high voltage generation circuit that generates a high voltage for a flash lamp that thermally fixes toner by switching a predetermined AC power source; and a trigger circuit that brings the high voltage generation circuit into conduction for lighting the flash lamp. The device includes a first detection means for detecting a predetermined voltage as a charge completion signal, and a second detection means for detecting another predetermined voltage as a discharge completion signal, and detects the flash lamp based on the detection results of both the detection means. A flash lamp lighting check method characterized by checking the lighting state of a flash lamp.