JPH0582151B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high-voltage power supply device for separating paper in a copying machine.

Conventional configuration and its problems Conventionally, an AC high-voltage power source has been used to separate paper in copying machines. This is because the surface of the photoreceptor is charged by DC high voltage, exposed to light, developed with toner, and transferred to the photoreceptor in the transfer process, where it is transferred to the next paper separation process. is adsorbed on the surface of the photoreceptor, and the electric charge on the photoreceptor, paper, and toner is erased by a high AC voltage with a DC bias, thereby suppressing electrostatic attraction force.

As this high-voltage power supply for paper separation, a switching regulator of a circuit type as shown in FIG. 1 is used. An overview of the configuration and operation of the high-voltage power supply device for paper separation shown in FIG. 1 will be explained.

Input terminal 13 and ground terminal 14 from DC power supply
When a DC input is applied between the oscillation and pulse width control circuit 1, the pulses A and A'
Supplied to Q ₁ and Q ₂ . Note that the frequency of pulse A is 1/2 that of pulse A'. When the pulse A _' is high and the pulse A is low, the transistor Q1 becomes conductive and turns on the transistor _Q3 . Also, transistor Q ₂ receives both pulses A and A'.
Turn on transistor _Q4 at the high timing.
That is, by pulse A, transistors Q ₃ and Q ₄
are turned ON alternately, and their ON time is a pulse.
This occurs only when A' is High. Transistors Q ₃ , Q ₄
By alternately repeating ON and OFF, a rectangular wave AC input is applied to the primary winding W of the transformer T by the switching means composed of transistors Q ₁ , Q ₂ , Q ₃ , and Q ₄ . An AC high voltage is generated in the secondary winding H, and an AC voltage for detection is generated in the detection winding B. In this example, the leakage inductance of the secondary winding H is generated by the shunt core 7, a resonant circuit is created with the capacitor _C1 , and the secondary winding is determined by the turns ratio of the primary winding W and the secondary winding H. By obtaining a secondary winding voltage much higher than the voltage, the number of turns of the secondary winding H is reduced. The AC output terminal 5 is electrically connected to a paper separating corotron of the copying machine. Further, the DC output terminal 5' is connected to a charging corotron or a transfer corotron of a copying machine. In addition, the first
In the circuit example shown in the figure, the circuit has a DC output, but the DC output is diode D, capacitor C ₂ ,
There are high-voltage power supplies that do not have a resistor R and output only AC, and conversely, there are also high-voltage power supplies that have multiple DC outputs or multiple AC outputs including one for static elimination. The voltage of the detection winding B is rectified by the adjustment circuit 15 and OP
In the amplifier 2, it is compared with the voltage of the reference voltage power supply 4, amplified, and fed back to the oscillation/pulse width control circuit 1 to control the high width of the pulse A', even if the input conditions and load conditions change. , the detection voltage 16 is always maintained constant, and the magnetic flux density interlinking with the secondary winding H and the detection winding B in the transformer T is constant, thereby stabilizing the output voltage.

In such a high-voltage power supply device for paper separation, the oscillation frequency is generally selected between 400 and 1000 Hz in order to minimize the size of the device in consideration of paper separation needs and load capacity loss. For this reason, the iron core 6 of the transformer T is relatively weak in this frequency range.
A grain-oriented silicon steel plate with low iron loss is used, which allows high magnetic flux density with low iron loss.
A primary winding W, a secondary winding H, a detection winding B, and a shunt core 7 are assembled into this core 6 to form a transformer as shown in FIG. 3 or FIG. 7.
Note that 17 is an insulating plate that electrically insulates between the secondary winding H and the iron core 6. Secondary winding H and detection winding B
is wound on the same bobbin (winding frame), and conventionally, the main method was lap winding, in which copper wire 8 and interlayer insulating paper 9 were wound alternately or in several layers on top of the bobbin 10, as shown in Fig. 2. In recent years, with the development of winding technology and winding equipment, automatic winding and wiring, and high-speed winding are possible.
As shown in the figure, split winding has become the mainstream. As shown in Figs. 4 and 5, the bobbin 11 is vertically divided into a plurality of winding grooves by a collar 12, and the secondary winding H and the detection winding B shown in Fig. 6 are wound therein. It is. The detection winding B is wound in the leftmost winding groove in FIG. 5, and the secondary winding H is wound in the leftmost winding groove.
It is wound in a winding groove of l~8l. The reason why the secondary winding H and the detection winding B are wound in separate winding grooves and insulated by the collar 12 is that the voltage of the detection winding B is normally
20V ^rms , DC bias is applied to the secondary winding H even at the lowest potential _H1 part by the DC bias circuit 3 shown in Figure 1, and normally
This is because the potential is often between 100V and 500V ^DC . The outline of the operation of the circuit shown in Figure 1 is as described above, but the DC bias of the AC output that supplies AC high voltage to the paper separation unit has an important effect on paper separation performance, and it is necessary to adjust the AC output to the paper separation unit according to the set specifications of the copying machine. Determine the voltage value of the DC bias of the lever. However, for this reason, the split-winding bobbin 11 must be provided with a special winding groove for the detection winding B, and the layer of the detection winding section with an extremely small number of turns has a lot of space, including the collar 12 for this purpose. However, this method has the disadvantage that there is a large space loss, and as a result, it is difficult to downsize the transformer.

Purpose of the Invention The present invention has the drawbacks mentioned above, namely, that a special winding groove must be provided for the detection winding, and there is a large amount of space in the detection winding section with very few windings, including the collar for this purpose. This was done in view of the fact that the space loss was large and as a result, the transformer could not be downsized.This paper was developed for copying machines that could be downsized by making it possible to omit the special groove for the detection winding. The present invention provides a high-voltage power supply device for separation.

Structure of the Invention In order to achieve this object, the high-voltage power supply device for paper separation in a copying machine of the present invention winds a detection winding serving as a first winding in one winding groove of a bobbin in a transformer. A second winding is wound on top of the first winding, and both ends are fixed to a part of the collar of the bobbin without electrical connection, and a third winding, which becomes a secondary winding, is wound on top of the second winding.
The second winding connects the detection winding and the second winding.
It is constructed by insulating the secondary winding, incorporating the bobbin into the iron core, and electrically connecting the detection winding and the secondary winding to other circuit components.

With this configuration, the detection winding and the secondary winding are completely insulated by the second winding without the need for an insulating bobbin collar, and a special bobbin winding for the detection winding is used. Line grooves and collars are no longer necessary.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 8 and 9 are drawings showing a bobbin structure and winding state according to an embodiment of the present invention.
For convenience of drawing, the width of the winding groove for winding the first layer (1l) of the detection winding B, the waste winding D, and the secondary winding H is drawn wide, but in reality, the width of the winding groove for winding the first layer (1l) of the detection winding B, the waste winding D, and the secondary winding H is drawn wide. Discarded winding D
The volume ratio of the secondary winding H is extremely small and can be ignored, and the number of turns per layer can be determined according to the predetermined number of divisions of the secondary winding H.
The width of the winding groove in which the first layer (1l) of the disposable winding D and the secondary winding H is wound is usually the same as the width of the other winding grooves. D ₁ and D ₂ are protrusions around which the winding start and winding end of the disposable winding D are wound and fixed, and are made of the same material as the bobbin 11 and are formed when the bobbin 11 is formed. Therefore, the disposable winding D is in a state where there is no electrical connection, and it is not connected to the outside like the terminals B ₁ and B ₂ of the detection winding B and the terminals H ₁ , H ₂ , and H ₃ of the secondary winding H. They are different from metal terminals that make electrical connections. As shown in FIG. 9, the first winding, which is the detection winding B, is first wound around the terminals B ₁ and B ₂ in the same winding groove. Next, wind the second winding D, which is a waste winding, until the detection winding B becomes calm (usually 2 to 3 layers are stacked).
Wrap it around the insulating protrusions D ₁ and D ₂ . Thereon, the winding start of the secondary winding H, which is the third winding, is wound around the terminal _H1 , and then wound in order from the second winding groove 2l to the seventh winding groove 7l. Wrap the middle tap around terminal _H2 and the end of the winding around terminal _H3 . In addition, the detection winding B,
The waste winding D and the secondary winding H may have the same wire diameter.
In terms of current, any winding wire with a diameter of φ0.04 or less is acceptable, but in general, φ0.05 to φ0.07 are often used depending on the winding method. In addition, the discarded winding D
Since no current flows through the terminals B ₁ , B ₂ and the insulating protrusion,
It is possible to continuously wind each detection winding B, waste winding D _, and secondary winding H while winding the taps around D ₁ , D ₂ , terminals H 1 , H ₂ , and H ₃ . FIG. 10 is a line diagram at this time.

Now, FIG. 11 shows the detection winding B, the discarded winding D,
FIG. 3 is an enlarged sectional view of a winding groove around which a secondary winding H is wound. In this embodiment, a case will be described in which 500 V DC is applied to the secondary winding H as a DC bias voltage. The part where the secondary winding H contacts the sacrificial winding D is approximately 0V in terms of AC, and it can be considered that only 500V DC is applied thereto. Also, the detection winding B is
AC is about 20V ^rms , and the DC bias is 0V, so for convenience, consider both AC and DC to be 0V. The sacrificial winding D is not electrically connected anywhere, and if the insulation coatings of the copper wires of the detection winding B, the sacrificial winding D, and the secondary winding H have the same thickness, the voltage will be DC250V. Therefore, between the secondary winding H and the discarded winding D, and between the discarded winding D and the detection winding B
The potential difference between both is 250V DC. On the other hand, the 12th
The figure shows the case where there is no disposable winding D, and the secondary winding H-
A potential difference of 500V DC occurs at the part where the copper wires between the detection windings B are in contact.

By the way, Figure 13 shows the V-T of polyurethane copper wire (a) with a copper wire diameter of 0.05 and two types of polyurethane copper wire (b) with a copper wire diameter of 0.05 which are commonly used in electronic equipment. The time required for dielectric breakdown of the copper wire film against the applied voltage, which is called a characteristic, is plotted and made into a curve, taking into account the temperature rise of the transformer.
Tested at 80℃. In addition, one type of copper wire,
The two types represent the types of insulation film thickness, and the first type has a larger insulation film thickness. The test piece was made by folding an appropriate length of copper wire in half and applying a tension of 3g to the
After aligning the 12 cm long pieces with 50 twists, remove the tension, cut the folded part and make these 2 pieces.
The time required for dielectric breakdown was determined by applying voltages of 50 Hz at various levels between the wires. In this graph, it can be seen that since semi-permanent insulation can be ensured between adjacent copper wires, the voltage is 350V ^rms (495V peak) for one type of copper wire, and 300V ^rms (425V peak) for two types of copper wire. Converting this to 1 mm, the insulation film thickness for one type of copper wire is 0.009 mm.
495V peak/0.018mm=27.5KV peak/mm. The 14th is an enlarged and electric field distribution diagram of the 11th. Between the secondary winding H and the waste winding D and the waste winding D
The electric field strength between the detection winding B and the detection winding B is 13.9 KV ^DC /mm, which is sufficient for the semi-permanent use limit of 27.5 KV peak/mm for one type of copper wire. However, if there is no waste winding D, the electric field strength will be
27.8KV peak/mm, exceeding the limit value,
Unusable. That is, since the electric field strength between adjacent insulating coated copper wires is reduced by the discarded winding D, a special winding groove and collar are provided for the detection winding B as in the conventional case, and the detection winding B to the secondary It becomes unnecessary to insulate the windings H. Note that C in FIGS. 14 and 15 represents an insulating film.

Effects of the Invention As described above, the present invention electrically insulates the first and third windings in the same winding groove by the second winding in one winding groove. It is no longer necessary to provide special winding grooves and flanges on the bobbin to insulate the windings of the transformer, which prevents space loss and allows transformers to be made smaller and lower in cost, which is of great practical value. be.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an example of a high-voltage power supply device for paper separation in a copying machine, FIGS. 2 to 7 are diagrams showing conventional high-voltage power supply devices for paper separation, and FIGS. 2A to C show detection windings. , a front view, a right side view and a sectional view of the wire ring of the secondary winding, Figures 3A to C are a front view, a top view and a side view of a transformer using the winding shown in Figure 2, and Figure 4 is a A perspective view of the bobbin for the detection winding and secondary winding, which is different in structure from Figures 2 and 3, Figure 5 is a cross-sectional view of the coil, Figure 6 is a circuit diagram of the coil, and Figure 7. A to C are a front view, a plan view and a side view showing the assembled state of the transformer,
Figures 8 to 15 are diagrams used for an embodiment of the present invention and its supplementary explanation; Figure 8 is a perspective view of the bobbin;
Figure 9 is a cross-sectional view of the wire, Figure 10 is a circuit diagram of the wire, Figure 11 is a cross-sectional view of the detection winding, sacrificial winding, and secondary winding, and Figure 12 is the sacrificial winding from Figure 11. 13th is a V-T characteristic diagram of 1 type and 2 types of polyurethane copper wire wire diameter φ0.05, 1st
Figure 4 is an enlarged view of Figure 11 and the electric field distribution diagram, Figure 15.
The figure is an enlarged view of FIG. 12 and an electric field distribution diagram. 1...Oscillation/pulse width control circuit, 2...OP amplifier, 3...DC bias circuit, 4 reference voltage power supply, 5...AC output terminal, 5'...DC output terminal,
6... Iron core, 7... Shunt iron core, 8... Copper wire,
9... Interlayer insulating paper, 10... Bobbin, 11... Bobbin, 12... Bobbin collar, 13... Input terminal, 14... Earth terminal, 15... Rectifier circuit, 1
6...Detection voltage, 17...Insulating plate, A...Pulse output, A'...Pulse output, _Q1 , _Q2 , _Q3 , _Q4 ...
Transistor, T...transformer, W...primary winding, B...detection winding, _B1 ...detection winding start terminal, _B2 ...detection winding end terminal, H...2
Secondary winding, H ₁ ... Secondary winding start terminal, H ₂ ...
Intermediate tap terminal of secondary winding, H ₃ ... winding end terminal of secondary winding, 1l to 8l ... winding groove of secondary winding,
D...Discarded winding, D ₁ ...Start of discarded winding, D ₂
... End of discarded winding, ST ... Start of winding, FIN...
... End of winding, D ... Diode, C ₁ , C ₂ ... Capacitor, R ... Diode, C ... Insulating film of copper wire.

Claims (1)

[Claims] 1 Oscillation that generates pulses by applying DC input
A copy consisting of a pulse width control circuit, switching means for inputting the output of the oscillation/pulse width control circuit and converting it into AC output, and a transformer for inputting the AC output output from the switching means and generating high voltage. In the high voltage power supply for paper separation of the machine, a first winding is wound in one layer of the bobbin of the transformer, a second winding is wound on top of the first winding, and both ends are electrically connected. The third winding is placed on top of the second winding, and the second winding electrically insulates the first and third windings. , a high-voltage power supply device for paper separation in a copying machine, which includes a bobbin assembled into an iron core and first and third windings electrically connected to other circuit components.