JPH0443904Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to a flash fixing device, and in particular,
The present invention relates to a flash fixing device that can operate efficiently without malfunctioning even when using a commercial power source with a frequency of 50 Hz or 60 Hz. [Background of the invention] For example, in devices such as copying machines, facsimile machines, and laser printers, a visible image is formed by fixing a toner image formed by development onto a fixing support, usually made of paper. As a method for fixing toner images, a heat roller fixing method using a heat roller is conventionally known. However, in this heat roller fixing method, at the beginning of image formation, a waiting time is required for the heat roller to rise to the temperature required for fixing the toner, and this waiting time is especially necessary when the environmental temperature is low such as in winter. The problem is that it becomes quite long. For this reason, recently, a flash fixing method has been attracting attention, in which a flash lamp is used as a heat source for fixing, and a toner image is fixed by utilizing the optical energy from the flash lamp. According to such a flash fixing method, the flash lamp can be turned on instantly, and there is an advantage that the fixing process can be performed immediately without requiring standby time. [Prior Art] FIG. 4 shows an example of a flash lamp power supply circuit 40 used in such a flash fixing device. In the same figure, 31 is a power transformer, 34
is a rectifier circuit, 35 is a main capacitor for energy supply, 37 is a commercial power supply with a frequency of 50Hz or 60Hz,
38 is a switching circuit made of a semiconductor switching element such as a solid state relay; 39 is a control circuit for controlling the on/off operation of the switching circuit 38; 10 is a flash lamp;
1 is a power factor improving reactor, 42 and 43 are power factor improving capacitors, and 44 and 45 are changeover switches. The power factor improvement reactor and the power factor improvement capacitor increase the power factor when charging the main capacitor 35 for efficient charging, and also serve as a semiconductor switching device that constitutes the switching circuit 38 when charging the main capacitor 35. This is provided to complete charging of the main capacitor 35 within an appropriate time corresponding to the light emission cycle of the flash lamp 10 while preventing excessive current from flowing through the element. From this point of view, the changeover switch 44 connects the terminals 44A and 44C, and the changeover switch 45 connects the terminals 45A and 44C.
5B is open (state shown), the values of the inductance due to the reactor 41 and the capacitance due to the capacitor 42 are equal to the frequency
It is a value that resonates when using a 60Hz commercial power supply, and on the other hand, the changeover switch 44 causes the terminal 44B to
and terminal 44C are connected, and when terminal 45A and terminal 45B are connected by changeover switch 45, the values of inductance due to reactor 41 and capacitance due to capacitors 42 and 43 are the same as when using a commercial power supply with a frequency of 50 Hz. The constants of the reactor 41 and the capacitors 42 and 44 are selected in advance so as to have resonant values. [Problem to be solved by the invention] Therefore, the operator must check whether the frequency of the commercial power source 37 to be used is 50Hz or 60Hz before performing the switching operation using the changeover switches 44 and 45. Is required. However, if the operator forgets to perform the above-mentioned switching operation or performs the above-mentioned switching operation incorrectly, the input current will increase, and as a result, the power transformer 31, power factor correction reactor 41, etc. will burn out. There is a problem in that accidents such as these occur, and the service life of the power supply circuit 40 is shortened. [Purpose of the invention] The present invention was developed based on the above-mentioned circumstances, and its purpose is to eliminate the need for switching operations by the operator when using a commercial power source with a frequency of either 50Hz or 60Hz. It is an object of the present invention to provide a flash fixing device which can be operated properly without causing any malfunction. [Means for Solving the Problems] The flash fixing device of the present invention includes a flash lamp as a heating source and a power supply circuit for causing the flash lamp to emit light. The circuit includes a power transformer, a power factor correcting capacitor and a power factor correcting reactor connected to the secondary side of the power transformer, and a power factor correcting capacitor and a power factor correcting reactor connected downstream of the power factor correcting capacitor and power factor correcting reactor. a rectifier circuit, and a main capacitor for supplying energy for supplying luminous energy to the flash lamp, which is connected to the secondary side of the rectifier circuit; The reactor is characterized in that the values of the capacitance of the capacitor and the inductance of the reactor are selected to resonate for a specific frequency in the range 52-58 Hz. [Operation and Effect of the Invention] According to the invention, the power factor improvement capacitor and power factor improvement reactor constituting the power supply circuit can
The values of the capacitance of the capacitor and the inductance of the reactor are selected to resonate at a specific frequency within the range of ~58Hz, so when using a commercial power supply with a frequency of 50Hz or a commercial power supply with a frequency of 60Hz. In any case where a power source is used, a practically sufficient power factor improvement effect can be obtained, and the main capacitor can be charged in an appropriate amount of time corresponding to the flash lamp's light emission cycle. It does not require any switching operations, and can operate properly without malfunction when using commercial power sources with frequencies of either 50Hz or 60Hz. In other words, in flash fixing, the flash lamp repeatedly emits light in short cycles, so the charging time required for the charging voltage of the main capacitor to reach the set voltage required for light emission must be within an appropriate range corresponding to the light emission cycle. is required to be in
Moreover, this condition needs to be satisfied both when using a commercial power source with a frequency of 50 Hz and when using a commercial power source with a frequency of 60 Hz. As mentioned above, if you set the capacitance of the power factor correction capacitor and the inductance of the power factor correction reactor so that it resonates at a frequency of 52 to 58Hz, you can use a commercial power source with a frequency of 50Hz. Even when using a commercial power source with a frequency of 60 Hz, efficient charging can be performed with a practically sufficient power factor, and at the same time, it can be charged for an appropriate period of time corresponding to the flash lamp's light emission cycle. Charging of the main capacitor can be completed within [Specific Configuration] The present invention will be explained in detail below with reference to the drawings. FIG. 1 is an explanatory diagram schematically showing an example of a flash fixing device according to the present invention. Reference numeral 10 denotes a flash lamp as a heat source, such as a xenon flash lamp, and is held within a casing 11. Inside the casing 11, a gutter-shaped reflecting plate 12 made of aluminum, for example, is positioned to reflect the light from the flash lamp 10 toward the fixing support S, and at the bottom of the casing 11 is an opening for light projection. 13 is formed, and a transparent glass plate 14 is formed to close this opening 13.
is located. Reference numeral 30 denotes a power supply circuit for causing the flash lamp 10 to emit light, and this power supply circuit 30 is disposed below a carrier (not shown). As shown in FIG. 2, this power supply circuit 30 includes a step-up power transformer 31 whose secondary voltage is about 0.5 to 3 kV, and a power factor correction transformer 31 connected to the secondary side of this power supply transformer 31. Capacitor 32 and power factor improvement reactor 33, and these power factor improvement capacitor 32 and power factor improvement reactor 33
A rectifier circuit 34 connected to the latter stage, an energy supply main capacitor 35 connected to the secondary side of the rectifier circuit 34 for supplying luminous energy to the flash lamp 10, and a trigger circuit 36.
and a switching circuit 38 consisting of a semiconductor switching element such as a solid state relay.
and a control circuit 39 for controlling the on/off operation of this switching circuit 38.
37 is a commercial power source with a frequency of 50Hz or 60Hz. The capacitor 32 for power factor improvement and the reactor 33 for power factor improvement are configured such that the capacitance of the capacitor 32 and the reactor 33 resonate at a specific frequency within the range of 52 to 58 Hz.
The value of the inductance is selected. According to the device having the above configuration, the power factor improving capacitor 32 and the power factor improving reactor 33 that constitute the power supply circuit 30 are arranged so that the power factor improving capacitor 32 and the power factor improving reactor 33 resonate at a specific frequency within the range of 52 to 58 Hz.
Since the values of capacitance and inductance of the reactor 33 are selected, a practically sufficient power factor can be achieved whether a commercial power source with a frequency of 50 Hz or a commercial power source with a frequency of 60 Hz is used. Improvement effects can be obtained, and the main capacitor can be charged in an appropriate amount of time corresponding to the flash lamp's light emission cycle.
As a result, there is no need for switching operations by the operator, and the system can be operated efficiently without malfunctioning when using commercial power sources with frequencies of either 50 Hz or 60 Hz. That is, in flash fixing, since the flash lamp 10 is caused to emit light repeatedly in short cycles, the charging time required for the charging voltage of the main capacitor 35 to reach the set voltage required for light emission is set to an appropriate time corresponding to the light emission cycle. Moreover, this condition must be satisfied both when using a commercial power source with a frequency of 50 Hz and when using a commercial power source with a frequency of 60 Hz. Therefore, as described above, the capacitance of the power factor correction capacitor 32 and the power factor correction reactor 33 are adjusted to resonate at a frequency of 52 to 58 Hz.
By setting the inductance value of In addition, efficient charging can be performed with a practically sufficient power factor, and charging of the main capacitor 35 can be completed within an appropriate time corresponding to the light emission period of the flash lamp 10. In practice, when the flash lamp 10 is caused to emit light repeatedly with a cycle T, the resonance frequency is changed by appropriately selecting the capacitance of the power factor correction capacitor 32 and the inductance of the power factor correction reactor 33. As shown in Fig. 3, the time (charging time) t from the start of charging of the main capacitor 35 until reaching the set voltage necessary for the flash lamp 10 to emit light and the input current were calculated. It was measured. The results are shown in Table 1. Note that in Table 1, the values of charging time and input current are relative values.

[Table] As can be understood from the results in Table 1, if the resonance frequency of the power factor improvement capacitor 32 and power factor improvement reactor 33 is within the range of 52 to 58Hz, the When using power supply,
In addition, even when using a commercial power source with a frequency of 60Hz, the charging time will vary depending on the flash lamp 1.
This is within a practically appropriate range corresponding to a light emission period T of 0, and the main capacitor 35 can be efficiently charged without causing an excessive current to flow through the semiconductor switching elements constituting the switching circuit 38. On the other hand, if the resonant frequency of the power factor improvement capacitor 32 and the power factor improvement reactor 33 is too low or too high, the power factor decreases and the power factor improvement effect cannot be obtained, and the main capacitor is not charged. If the time becomes longer, it becomes difficult to charge the main capacitor in accordance with the light emission cycle of the flash lamp, or if the charging time of the main capacitor becomes shorter, an excessive current flows through the semiconductor switching element that constitutes the switching circuit 38, causing the element to become damaged. Problems such as destruction of the An example of the device according to the present invention has been described above, but in the present invention, the specific configurations of the switching circuit, its control circuit, rectifier circuit, trigger circuit, etc. are not particularly limited, and various configurations may be adopted. I can do it.

[Brief explanation of drawings]

Fig. 1 is an explanatory cross-sectional view schematically showing an example of a flash fixing device according to the present invention, Fig. 2 is an explanatory view showing an example of a power supply circuit, and Fig. 3 shows repeated charging and discharging of the main capacitor for energy supply. An explanatory diagram showing,
FIG. 4 is an explanatory diagram showing a power supply circuit in a conventional flash fixing device. 10... Flash lamp, 11... Casing, 12... Reflection plate, 13... Light projection opening, 1
4...Transparent glass plate, 30...Power circuit, 31...
...power transformer, 32... power factor improvement capacitor, 33... power factor correction reactor, 34... rectifier circuit, 35... main capacitor, 36... trigger circuit, 37... 50Hz or 60Hz commercial power supply, 3
8... Switching circuit, 39... Control circuit, 4
0... Power supply circuit, 41... Reactor for power factor improvement, 42, 43... Capacitor for power factor improvement, 4
4,45...changeover switch.

Claims (1)

[Claims for Utility Model Registration] A flash fixing device comprising a flash lamp as a heating source and a power circuit for causing the flash lamp to emit light, the power circuit comprising a power transformer and a power transformer. A power factor correction capacitor and a power factor correction reactor connected to the secondary side of the and a main capacitor for energy supply for supplying luminous energy to the flash lamp, which is connected to the next side, and the power factor correction capacitor and the power factor correction reactor are connected to the flash lamp, and the power factor correction capacitor and the power factor correction reactor have a A flash fixing device characterized in that the values of the capacitance of the capacitor and the inductance of the reactor are selected so as to resonate at a specific frequency.