JPH075775A - Image forming device for electronic copying machine - Google Patents

Abstract

PURPOSE:To prevent leakage and to apply stable DC chute bias voltage, having the same polarity as the transferring polarity, to the chute. CONSTITUTION:The device is constituted of the transfer auxiliary corotron 22 superposed with DC of polarity opposite to the transferring polarity, the shield 24 for an AC corotron such as a peeling corotron which is impressed at the shield part with the half-wave rectified voltage whose polarity is the same as the DC polarity of the AC corotron and grounded through the circuit capable of taking out the smoothly rectified output having the same polarity as the transferring polarity at the intermediate part of the circuit, and moreover, the smoothly rectified output 25 is electrically connected with the chute parts 14 and 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for an electronic copying machine, and more particularly to a potential control means in a transfer section and a chute section of a sheet supply apparatus as a countermeasure against a water-containing paper transfer failure in the transfer section. .

[0002]

2. Description of the Related Art As shown in FIG. 1, an image forming apparatus for an electronic copying machine has a light image entrance section 3 and a developing machine 4 in the order of rotation around a photoconductor 1 with a charger 2 as the most upstream side. , A transfer device 5, a peeling device 6, and a cleaning device 7 are provided so as to face each other, and a paper supply device 8 faces the transfer device 5.
Is provided. The transfer device 5 is composed of a transfer corotron wire 9 and a shield 10, and the paper feeding device 8 is provided with chutes 14 and 15 vertically opposed to a paper feeding roll 13 for feeding the paper 12 in the cassette 11.
And a guide plate 16 for guiding the paper 12 from the chute to the transfer device 5.

In the image forming apparatus of such an electronic copying machine, when the paper 12 supplied to the transfer device 5 contains water,
The sheet 12 serves as a conductor, and the transfer charge in the transfer device 5 is transmitted through the sheet 12 to cause a transfer failure.

Various proposals have heretofore been made as measures against the above-mentioned water-containing transfer failure, the main ones having the structure shown in FIG. 1 and further JP-A-1-274171.
No. 61-240265, 61-6767
No. 76 and Japanese Utility Model Publication No. 57-28454.

[0005]

In each of the above prior arts, the one shown in FIG. 1 has a structure in which a chute 14, 15 and a guide plate 16 are connected to a dedicated power source 17 having the same polarity as the transfer corotron wire 9. Has become. In the case of this configuration, a stable shoot bias can be obtained, but there is a problem that it becomes very expensive because a dedicated power supply is required.

Japanese Unexamined Patent Publication Nos. 1-274171 and 61-61
In the methods disclosed in both publications of No. 240265, the chute is independently grounded at a constant voltage, which has only the effect of reducing the outflow amount of the transfer current, and is not sufficient as a measure for defective transfer of water-containing paper. It was

The method proposed in Japanese Patent Laid-Open No. 61-37676 is as shown in FIG.
The shield 10 is grounded by interposing a resistor 18 and a capacitor 19 in parallel, and the chutes 14, 15 and the guide plate 16 are also shielded by the shield 1 of the transfer device 5 via another resistor 20.
The shield 10 is connected to the 0 side, and the shield 10 is grounded via a resistor to apply the voltage drop to the chute. With this configuration, as shown in FIG. 3, when the corotron discharge current A and the shoot bias voltage B change as the load resistance of the chute changes, and when the shoot bias voltage greatly changes with the load change of the chute, the corotron changes. There was a fatal defect that the discharge current could not be obtained and the corotron itself would not function.

The method disclosed in Japanese Utility Model Laid-Open No. 57-28454 is as shown in FIG. 4, in which only a part of the shield 10 is separated and insulated by an insulator 21. The charges received by the chutes 14 and 15 and the guide plate 16 are supplied. The corotron discharge current with respect to the load resistance in this case is as shown by C in FIG. 5, and the change of this corotron discharge current is not so large, but the shoot bias voltage is greatly changed with load change as shown by D. It is extremely unstable, which has a drawback that leakage occurs due to an increase in shoot bias voltage and transfer failure occurs due to a voltage drop.

The present invention has been made to solve the above-mentioned drawbacks of the prior art in which a shoot bias is obtained by utilizing a corotron, and can be made inexpensive without requiring a dedicated power source. At the same time, a stable shoot bias voltage can be obtained without inhibiting the function of the corotron, and it can be applied to an alternating current corotron in which a direct current with a reverse polarity and a reverse polarity is superimposed, and the shield reduces the electric field to the corotron. An object of the present invention is to provide an image forming apparatus for an electronic copying machine in which a half-wave rectified voltage of polarity is applied to prevent leakage and a stable shoot bias voltage of direct current having the same polarity as the transfer polarity can be supplied to the chute. It is what

[0010]

In order to achieve the above object, an image forming apparatus for an electronic copying machine according to a first aspect of the present invention is a transfer auxiliary corotron in which a direct current having a reverse polarity to a transfer polarity is superposed, and a peeling device. A shield of an AC corotron such as a corotron is applied with a half-wave rectification voltage of the same polarity as the DC polarity of the AC corotron to this shield part, and at the middle of the circuit, the output rectified and smoothed to the same polarity as the transfer polarity is taken out. The rectifying and smoothing output section and the chute section are electrically connected to each other while being grounded via a circuit capable of performing the above. According to a second aspect of the present invention, a shield of an AC corotron is applied, a half-wave rectification voltage having the same polarity as the DC polarity of the AC corotron is applied to the shield portion, and a half-wave rectification output having the same polarity as the transfer polarity is provided at the circuit middle. It is configured such that it is grounded through a circuit that can be taken out, and that the half-wave rectification output section having the same polarity as the transfer polarity and the chute section are electrically connected. Further, according to a third aspect of the present invention, the shield of the AC corotron is grounded via a circuit having a rectifying / smoothing effect having the same polarity as the transfer polarity, and the rectifying / smoothing output section and the chute section of the circuit are electrically connected. Has become.
Further, in claim 4, the rectifying / smoothing output portion in the configuration of claim 3 is grounded via a resistor.

[0011]

[Operation] A half-wave rectification voltage of the same polarity as the DC polarity of this corotron is applied to the shield part of the AC corotron, and an output rectified and smoothed to the same polarity as the DC polarity of the corotron is applied to the chute part. Alternatively, a half-wave rectified output is applied to the chute.

[0012]

[Embodiment] A first embodiment of the present invention will be described with reference to FIGS. In the following description of each embodiment, the same members as those in the configuration of the conventional example shown in FIGS. 1 to 5 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 6, reference numeral 22 is a transfer assisting corotron located upstream of the transfer corotron 5, which is an alternating current corotron, and is a corotron wire 2
A direct current having a polarity opposite to that of the transfer polarity of the transfer device 5 is superimposed on 3. A half-wave rectified voltage having the same polarity as the DC polarity applied to the corotron wire 23 is applied to the shield 24 of the transfer assisting corotron 22, and an output rectified and smoothed to have the same polarity as the transfer polarity is provided in the middle of the circuit. A rectifying / smoothing circuit 25 that can be taken out is connected.

That is, as shown in FIG. 6, the rectifying / smoothing circuit 25 includes a zener diode 26 and a capacitor 2.
The first circuit 28 in which 7 is connected in parallel and the second circuit 30 in which two Zener diodes 26 are connected in parallel in opposite directions and one of the diodes is connected in series to the capacitor 29 are connected in series. The first circuit 28 is connected to the shield 24, and the second circuit 30 is grounded. And the second circuit 30
The chutes 14 and 15 and the guide plate 16 are connected between the Zener diode 26 and the capacitor 29.

The AC discharge current of the corotron wire 23 with respect to the change in the load resistance of the chute portion in the first embodiment is shown by E in FIG. 7, and the DC discharge current is shown by F. Since the shield voltage acting on the shield 24 changes as shown by G, it can be seen that the original function of the corotron in the practical range is operating normally.

On the other hand, the concrete output waveform in this embodiment is as shown in FIG. 8, and the waveform H of the alternating current acting on the corotron wire 23 is offset by the superposition of the direct current, and the shield 24 shows I. As shown, a half-wave rectified voltage having the same polarity as the DC polarity of the corotron 23 acts.
In addition, J is attached to the chutes 14 and 15 and the guide plate 16.
As shown in, the voltage rectified and smoothed to the same polarity as the transfer polarity in the transfer device 5 is output. In the figure, a is the maximum electric field of the corotron.

FIG. 9 shows a modification of the first embodiment, in which only the guide plate 16 is used as a constant voltage element 31.
To ground. According to this configuration, it is possible to prevent toner stains on the guide plate 16 that is close to the photoconductor 1.

Next, a second embodiment of the present invention will be described with reference to FIGS. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Figure 1
At 0, as in the first embodiment, the transfer assisting corotron 22 is applied with an alternating current in which a direct current having a reverse polarity to the transfer polarity in the transfer device 5 is superimposed on the corotron wire 23 of the transfer assisting corotron 22. A half-wave rectified voltage having the same polarity as the DC polarity of the corotron wire 23 is applied to the shield 24 of the transfer auxiliary corotron 22, and a half-wave rectified output having the same polarity as the transfer polarity can be taken out in the middle of the circuit. A half-wave rectifier circuit 32 is connected.

That is, as shown in FIG. 10, the half-wave rectifier circuit 32 includes a zener diode 26 and a capacitor 2.
7 is connected in parallel to the first circuit 28, and another Zener diode 26 connected in series to the first circuit 28, the first circuit 28 is connected to the shield 24, The other Zener diode 26 is grounded. Then, the first circuit 28 and the Zener diode 26
The chutes 14 and 15 and the guide plate 16 are connected between and. The AC discharge current of the corotron wire 23 with respect to the change of the chute load resistance in the second embodiment is shown by K in FIG. 11, the DC discharge current is shown by L, and the shield voltage is M. It changes as shown in.

On the other hand, the concrete output waveform in this embodiment is as shown in FIG. 12, and the waveform N of the alternating current acting on the corotron wire 23 is offset by the superposition of the direct current, and the shield 24 is turned to O. As shown, a half-wave rectified voltage having the same polarity as the DC polarity of the corotron 23 acts. Further, as indicated by P, a half-wave rectified voltage having the same polarity as the transfer polarity in the transfer device 5 is output to the chutes 14 and 15 and the guide plate 16.

FIG. 13 shows a modification of the second embodiment described above, in which only the guide plate 16 alone is used as the constant voltage element 3.
Ground via 1 With this configuration, the guide plate 16 that is close to the photoconductor 1 is prevented from being contaminated with toner.

Next, a third embodiment of the present invention will be described with reference to FIGS. 14 to 17. The same components as those of the first and second embodiments are designated by the same reference numerals and the description thereof will be omitted. In FIG. 14, the transfer assisting corotron 22 is the corotron wire 2 of the same as in the first and second embodiments.
An alternating current in which a direct current having a reverse polarity to the transfer polarity in the transfer device 5 is superimposed is applied to 3. Then, the corotron wire 23 is attached to the shield 24 of the transfer assisting corotron 22.
A rectifying / smoothing circuit 33 having the same rectifying / smoothing effect as the polarity of the direct current is connected.

The rectifying / smoothing circuit 33 has the same structure as the second circuit 30 in the first embodiment, and the chutes 14, 15 and the plate 16 are provided between the Zener diode 26 and the capacitor 29 of the circuit 33. It is connected.

The alternating discharge current of the corotron wire 23 with respect to the change in the load resistance of the chute portion in this embodiment is shown by Q in FIG.
The shield voltage acting on 4 changes as shown by R.

On the other hand, the concrete output waveform in this embodiment is as shown in FIG. 16, and the waveform S of the alternating current acting on the corotron wire 23 is offset to the polarity opposite to the transfer polarity by the superposition of the direct current. , Shield 24 has T
As shown in, the half-wave rectified voltage having the polarity opposite to the direct current polarity of the corotron wire 23, that is, the same polarity as the transfer polarity acts. In addition, the chutes 14 and 15 and the guide plate 16
As indicated by U, a rectified and smoothed rectified voltage having the same polarity as the transfer polarity in the transfer device 5 is output to the U.

FIG. 17 shows a modification of the second embodiment, in which only the guide plate 16 is used as the constant voltage element 3.
Ground via 1 With this configuration, the guide plate 16 that is close to the photoconductor 1 is prevented from being contaminated with toner.

FIG. 18 shows another modification of the third embodiment, in which a resistor 34 is provided in parallel with the capacitor 29 of the rectifying / smoothing circuit 33. As a result, it is possible to prevent electric shock due to electric charges accumulated in the capacitor 29, such as removing jam.

[0027]

According to the present invention, an image forming apparatus using a corotron to obtain a shoot bias can be manufactured inexpensively without the need for a dedicated power source, and can function without impairing the function of the corotron. A stable shoot bias voltage can be obtained, and it can be applied to an alternating current corotron in which a direct current with a polarity opposite to the transfer polarity is superimposed, and a half-wave rectified voltage with a polarity that reduces the electric field to the corotron wire is applied to the shield. It is possible to prevent leakage by being applied, and to supply a stable DC shoot chute bias voltage having the same polarity as the transfer polarity to the chute.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view showing a first conventional example.

FIG. 2 is a structural explanatory view showing a second conventional example.

FIG. 3 is a diagram showing changes in a shoot bias voltage and a corotron discharge current with respect to a load change of a shoot unit in a second conventional example.

FIG. 4 is a structural explanatory view showing a third conventional example.

FIG. 5 is a diagram showing changes in a shoot bias voltage and a corotron discharge current with respect to a load change of a shoot unit in a third conventional example.

FIG. 6 is a structural explanatory view showing a first embodiment of the present invention.

FIG. 7 is a diagram showing changes in the shoot bias voltage and the corotron discharge current with respect to load fluctuations in the shoot unit in the first example of the present invention.

FIG. 8 is a diagram showing waveforms of a voltage of the corotron and a shoot bias voltage in the first example of the present invention.

FIG. 9 is a structural explanatory view showing a modification of the first embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a second embodiment of the present invention.

FIG. 11 is a diagram showing a shoot bias voltage and a corotron discharge current with respect to a load change of a shoot unit in the second example of the present invention.

FIG. 12 is a diagram showing waveforms of voltage and shoot bias voltage of a corotron wire in the second example of the present invention.

FIG. 13 is an explanatory diagram showing a modification of the second embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a third embodiment of the present invention.

FIG. 15 is a diagram showing a shoot bias voltage and a corotron discharge current with respect to a load change of a shoot unit in the third embodiment of the present invention.

FIG. 16 is a diagram showing waveforms of voltage and shoot bias voltage of a corotron wire in the third example of the present invention.

FIG. 17 is a structural explanatory view showing a modification of the third embodiment of the present invention.

FIG. 18 is a structural explanatory view showing another modification of the fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photosensitive member, 2 ... Charging device, 3 ... Light image entrance part, 4 ... Developing device, 5 ... Transfer device, 6 ... Separator, 7 ... Cleaning device,
8 ... Paper feeding device, 9 ... Transfer corotron wire, 10,
24, 27 ... Shield, 12 ... Paper, 13 ... Paper feed roll, 14, 15 ... Chute, 16 ... Guide plate, 1
7 ... Dedicated power supply, 18, 20 ... Resistor, 19 ... Capacitor,
21 ... Insulator, 22 ... Transfer auxiliary capacitor, 23 ... Corotron wire, 24 ... Shield, 25, 33 ... Rectifying / smoothing circuit, 26 ... Zener diode, 27, 29 ... Capacitor, 28, 30 ... First and second , 31 ... Constant voltage element, 32 ... Half-wave rectifier circuit, 34 ... Resistor.

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[Procedure amendment]

[Submission date] December 10, 1992

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Claims (4)

[Claims] 1. A shield of an alternating current corotron, such as a transfer assisting corotron and a peeling corotron, on which a direct current having a reverse polarity to the transfer polarity is superposed, and a half-wave rectified voltage having the same polarity as the direct current polarity of the alternating current corotron is provided on the shield part. In addition to grounding via a circuit that can be applied and rectified and smoothed to the same polarity as the transfer polarity in the middle of the circuit, the rectified and smoothed output section and the chute section are electrically connected. The image forming apparatus of the electronic copying machine that features. 2. A shield of an alternating current corotron, such as a transfer assisting corotron or a peeling corotron, on which a direct current having a reverse polarity to the transfer polarity is superposed, and a half-wave rectified voltage having the same polarity as the direct current polarity of the alternating current corotron is provided on the shield part. It is applied and grounded via a circuit that can extract a half-wave rectified output having the same polarity as the transfer polarity in the middle of the circuit, and the half-wave rectified output part and shoot part having the same polarity as the transfer polarity are electrically connected. Image forming apparatus of an electronic copying machine, which is characterized in that the image forming apparatus is connected to each other. 3. The shield of an alternating current corotron such as a transfer assist corotron and a peeling corotron on which a direct current having a reverse polarity to the transfer polarity is superimposed is grounded via a circuit having a rectifying and smoothing effect having the same polarity as the transfer polarity. An image forming apparatus for an electronic copying machine, wherein a rectifying / smoothing output section of the above circuit and a chute section are electrically connected. 4. An image forming apparatus for an electronic copying machine according to claim 3, wherein the rectifying / smoothing output section connected to the chute section is grounded via a resistor.