JPS5933478A - Fixation method of toner image - Google Patents

Abstract

PURPOSE:To make it possible to use a small-capacity power source, by lighting plural flash lamps successively at intervals of a certain time to fix a toner image onto a carrier. CONSTITUTION:Each time the carrier rus for a length L, a pulse is generated by a carrier running speed detecting circuit, and this pulse is inputted to a shift register as a clock. Driving circuits of switches SW1-SW5 are operated successively by this pulse to turn on and off switches SW1-SW5. Since flash lamps FL1-FL5 are lit successively, charge start times of main capacitors C1-C5 are shifted from one another. Consequently, a maximum current at the charge start time is dispersed in charging of the main capacitors C1-C5, and the current supplied from the power source is averaged as the whole. Thus, the small- capacity power source can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of fixing a toner image onto a carrier such as paper at high speed using a large number of flash lamps in an electrophotographic process.

In a low-speed electrophotographic process, when a toner image carried on a carrier such as paper running at a constant speed is fixed on the carrier by a flash run, one or two flash lamps are used. This flash lamp
Figure 1 shows a basic flashlight lighting circuit used in such a fixing method. In the figure, 1 and 2 are input terminals, and a power supply (not shown) of approximately 100 VAC is connected to these input terminals 1 and 2.
The rectified waveform 5 shown in FIG. 2(a) is formed by a bridge rectifier circuit consisting of diodes D1 to Dq shown as an example of a full-wave rectifier circuit. ing. Then, the current passes through a series circuit of the resistor R and the main capacitor C, and the voltage of the main capacitor C is charged to about D·,elLOo ov by n.

Here, the output voltage of the full-wave rectifier circuit is 1, and the voltage of the main capacitor C is V. Then, charging takes place at V r
) V c.

On the other hand, a DC power supply (not shown) of several tens of volts is connected to other input terminals 3 and 4, and a trigger capacitor C'
is charging. FL is a flash lamp used to fix the toner image on the carrier, and SW is a switch that causes the flash lamp FL to flash.When this switch SW is turned on, the instantaneous discharge current of the trigger capacitor C' is used for triggering. A high voltage flows to the primary side of the transformer T', generates a high voltage in the secondary side trigger coil TC, and induces discharge of the electric charge that has been accumulated in the main capacitor C from both electrodes of the flash lamp FL. flashes.

In this circuit, for example, one flash lamp FL with a two-arc length of 300 mm and a tube outer diameter of 16 mm is connected to IH.

When flashing at a period of
A 0V power supply will be about IQA.

FIG. 2(b) shows the charging waveform 6 of the main capacitor C when the charging start time of the main capacitor C coincides with the zero volt time of the rectified waveform 5, and FIG. 2(c) shows the charging waveform 6 of the main capacitor C when the charging start time of the main capacitor The charging current γ of C is shown.

As can be seen from the charging current I in Fig. 2(c), if one period is from zero volt to the next zero volt t of the rectified waveform 5, the main capacitor C is charged, and as the potential increases, each As the charging time for each cycle becomes shorter, the magnitude of the charging current 70 also decreases.

Therefore, the power supply capacity is determined by the magnitude of the current flowing in the first cycle 1tll or the second cycle of the rectified waveform 5 when charging of the main capacitor C starts.
The magnitude of the maximum charging current can be changed by shifting the phase of the start of charging of the main capacitor C with respect to the cycle of Problem (good, main capacitor C
After the second or third period of the rectified waveform 5 from the start of charging, the magnitude of the charging current 70 and the charging time decrease, and the power source is not used effectively.

Incidentally, in a high-speed electrophotographic process, in order to fix a toner image on a carrier, several to ten or more flash lamps are required depending on the speed.

The lighting circuit shown in Figures 8 and 3 has n flash lamps connected in parallel as shown in Figure 1, with a common bridge rectifier circuit, in order to flash n flash lamps during high-speed fixing. When the switches SW1 to SWo are made conductive at the same time, the flash lamps FLI to FLn
flashes at once, and immediately after that the main capacitors C1 to Co
The photoelectric waves are set to start at the same time.

Therefore, in a fixing method that uses the circuit shown in Figure 3 to flash multiple flash lamps at once, a power supply with a capacity n times that of the power supply used in the circuit shown in Figure 1 is required.
Another disadvantage is that a smoothing circuit with a large capacity is required at the stage following the rectifier circuit in order to reduce the burden on the power supply. One object of the present invention is to solve the above-mentioned drawbacks.For this purpose, a plurality of flash lamps are arranged at equal intervals so that their longitudinal direction crosses the running direction of the toner image carrier. The method is characterized in that the order and time for flashing each of the flash lamps are determined, and the flash lamps are sequentially closed at regular time intervals to fix the toner image on the carrier.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 4(a) is a simplified sectional view of the fixing device used in the present invention. Although lamps are used, only five flash lamps 'FL1 to FL5 will be shown and explained here.

In FIG. 4(a), 8 is a carrier that runs at a constant speed in the direction of the arrow, 9 is a toner image carried on this carrier 8, and 10
is a reflecting plate installed behind the flash lamps FLI to FL5 in order to improve the fixing efficiency of the toner image 9.

Each of the flash lamps FL1 to FL5 is arranged at intervals of a distance across the running direction of the supporting body 80, and the flash lamps FL1 to FL5 are arranged in the drawing as shown by the arrows in the supporting body 8. When driving in the direction of
The direction dimension opposite to this running direction, that is, from right to left, is FL.
They are arranged like 1, FL2...FL5.

Here, each of the flash lamps FL1 to FL5 has 4
- If the width in which the toner image 9 can be fixed along the running direction of the eye holder 8 is L', then the width is L (L' is set to 11, and in the toner image fixing operation described later, the unfixed portion is 〇And in this example,
Now, if the time is 1=0, then flash run F
The area of the carrier 80 where the toner image 9 is fixed by flashing the LI is P1, the area of the carrier 8 where the toner image 9 is fixed by the flash of the flash lamp FL2 is P2, and the same goes for the flash lamp FL. FL4. FL5
The areas of the carrier 8 where the toner image 9 is fixed by the flash of light are respectively defined as p5 + pHt' p5. This area P1
~P5, the flash lamps FLl~FL5 are rod-shaped,
Since they are arranged across the carrier 8, they are in the form of a band with a width L' and extending in the longitudinal direction of each of the flash lamps FL1 to FL5 (7), and are lined up at a pitch of a certain distance. Continuing from the areas P1 to P5, band-shaped areas with a width L' are set at distance pitches in the direction opposite to the arrow shown in the figure, and 71. Identification numbers are assigned as P6, P7, etc.O. FIG. 4(b) is a time chart when the fixing method of the present invention is carried out using the above-mentioned apparatus, and the flash lamp shown in FIG. 4(a) is used. The position of the carrier 8 from time 1=0 to t=10T is shown based on FLI to F.L5. Here, T represents the time required for the carrier 8 to travel the distance, and if the travel speed of the carrier 80 is f:V, then T=L/V.

Therefore, as shown in FIG. 4(b), when the flattening lamp FL1 is flashed at time 1=0, the toner image 9 in area P1 is fixed, and then at time t=T, the flash lamp
When Lz is flashed, the toner image 9 in area P3 is fixed, and the flattening lamp FLI,
The operation of flashing the flash lamps in the order of FL2...FL5 and flashing the flash lamp FL1 after the flash lamp FL5 is repeated.

In FIG. 4(b), the area P surrounded by a circle indicates the area where the toner image 9 was fixed when the flash lamps FLI to FL5 were flashed as described above. The areas of the carrier 8 where the toner images 9 are fixed in order from time 1=0 are P1→P5→P5→P7→
P9→P6-+ p8. Pio.

P12→Pl+1−+pH→・Φ・・ It will be as follows.

In this case, the toner image 9 is unfixed in areas P2 and Pll, but this is due to an initial setting problem, or the toner image 9 was originally fixed before 20, or the toner image 9 is not fixed at the end of the carrier 8. This is a part that does not require fixing, and everything beyond the area P5 to be fixed is fixed.

If the travel of the carrier 8 is to be stopped for a while, if the lighting circuit is equipped with a function to remember the last flash lamp and flash from the next flash lamp, the area P2 described above can be used. ．． P.I.

There will be no unfixed areas like this.

FIG. 5 is a diagram showing an example of a lighting circuit used in the above-described embodiment. This lighting circuit prevents charging between the main capacitors C1 to C5.
~D/ is added, and the other configurations are the same as in Figure A) 3.

FIG. 6 is a block diagram showing an example of the configuration of a circuit that drives the switches SW1 to SW5 in FIG. A carrier tip detection circuit 12 is an initial setting circuit that performs initial setting to sequentially flash light from an arbitrary flash lamp when the tip of the carrier 8 is detected.

In this embodiment, for example, when the tip of the supporting body 8 comes directly under the flash lamp FL3, the numbers F'l, FL)1, F'l, and FL)1, 5, and 5 are sequentially changed. FL5. By flashing light like FL6..., it is also possible to magnetize the unfixed part mentioned in AiJ, so that the supporting body 8 can be used not only for continuous paper but also for
It can also be applied to cut paper.

Reference numeral 13 denotes a carrier traveling speed detection circuit, which generates a pulse every time the carrier 8 travels a certain distance, and this pulse is clocked into the shift register 14.

As a result, the drive circuit 151 of switches SWI to SW5
~ ] 55 are operated in sequence, and switches SW1 to SW5 are turned to O.
N, turn off.

In this way, switch sw1. sw2...SW5
．． SWl, sw2, etc. are made conductive one after another in that order, and part 1.
Since the flattening lamps FLI to FL5 are sequentially flashed in accordance with the time, the charging start time of the main capacitors C1 to C5 can be shifted. Therefore, in charging the main capacitors C1 to C5, the maximum current at the start of charging can be made into a fraction, and the current supplied from the power source as a whole can be averaged.

On the other hand, it is also possible to control the main capacitors C1 to C5 by constant current, and a lighting circuit in that case is shown in FIG. , Here, for comparison with the lighting circuit of Fig. 1, Fig. 7 shows the lighting circuit of one flash lamp FL.
, 16 in the figure is a constant current control circuit. In this case, the rectification waveform 5 and the charging waveform 17 of the main capacitor C are shown in FIG. 8(a), and the current waveform 18 is shown in FIG. 8(b).

As seen in Fig. 8 (aL (b)), the maximum value of the photoelectric current is constant, but the charging time decreases with each cycle of the rectified waveform 5 from the start of charging. In order to flow current, a smoothing circuit is required before the constant current control circuit 16, and this trick requires multiple flash lamps F.
The same thing can be said when flashing L1 to FLn at once and simultaneously starting charging the main capacitors C1 to Cn through the constant current control circuit 16. That is, in the lighting circuit shown in FIG. 3 and the circuit shown in FIG. 7 equipped with the constant current control circuit 16, a smoothing circuit with a large capacity is generally required.

However, in the fixing method based on the present invention, the smoothing circuit is not used or a smoothing circuit with a small capacity is provided.
The current flowing from the power supply can be averaged. hot theory,
If the above-described fixing method according to the present invention is carried out using the lighting circuit equipped with the constant current control circuit 16 shown in FIG. In the above embodiment, a method of fixing a toner image using an odd number of flash lamps was explained, but even if the number of flash lamps is an even number. The second flash is from the flash lamp FLl of the first main port, and the second flash is from the flash lamp F of the second main port.
If the timing of the flash start is shifted, such as starting from L2 and the third flash is again from the flash lamp FL1 of the first main port, the entire surface of the carrier 8 will be illuminated as in the case of an odd number of flash lamps. The toner image 9 can be fixed.

As explained above, the present invention charges the main capacitor of each flattening lamp in order to cause each of the plurality of flashlungs to flash at regular time intervals to fix a toner image on the carrier. Because there is a time delay tL in the current, and therefore the photoelectric current is averaged out, it is possible to prevent large currents from flowing, such as when charging multiple main capacitors simultaneously. That is, the present invention has the effect that a power supply with a small capacity can be used, and also has the effect that a smoothing circuit is not required or the capacity of the smoothing circuit can be reduced. Since multiple flash lamps are not flashed at once, it is effective for noise control and light shielding.
It can be used in high-speed printers, high-speed copying machines, etc. using electrophotographic processes.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the basic lighting circuit when using one flat yurung, Figures 2 (a), (b) and (c)
) is a diagram showing the rectifying waveform of the full-wave rectifier circuit, the charging waveform and charging current of the main capacitor in Figure 1, Figure 3 is a diagram showing a lighting circuit that flashes n flashlungs simultaneously, and Figure 4 (a ) and (b) are simplified cross-sections of the device for carrying out the toner fixation method according to the present invention and time charts showing its operation; FIG. 5 is a diagram showing an example of a lighting circuit used in the present invention; FIG. is a diagram showing an example of the configuration of a circuit that drives the switch in FIG. 5, FIG. 7 is a diagram showing a lighting circuit when charging the main capacitor with a constant current, and FIG.
Figures (a) and (b) are diagrams showing charging waveforms and current waveforms in FIG. 7. T...Transformer D1~DI+...Diode R
, R1-Rn... Resistance C, C1-Co,... Main capacitor FL. FLI~FLn...Flash lamp TC,'rc
i~TCn...Trigger coil T', T'1~T
'n...Trigger transformer SW, SWt ~SW,
-...Switch C'90'1~C/n...Trigger capacitor D1~D'5...Diode R',
R'l~R'. ...Resistor 1, 2, 3.4...Input terminal 8...Carrier 9...Toner image 11...
- Carrier bear tip 1] U circuit 12... Initial set circuit 13... Carrier running speed detection circuit 14... Soft registers 151 to 155... Switch drive circuit 1
6. . , Constant Current Control Circuit Patent Applicant: Oki Electric Industry Co., Ltd. Agent, Patent Attorney: Takashi Kanakura, 5t17')

Claims (1)

[Claims] 1. A plurality of flashlamps are installed along the running direction of the carrier so that the longitudinal direction of the flashlamps crosses the carrier carrying the toner image, and the plurality of flashlamps are flashed to carry the toner image. This is a method of fixing the flash lamps on the body, where the installation interval of the flash lamps is L1, the running direction of the carrier is V, and the number of flash lamps is from the end in the opposite direction to the running direction of the carrier, FLl*FL2...
- A toner image fixing method characterized by sequentially flashing a flash lamp at time intervals T=L/V, where FLn.