JPH06202495A - Image forming device for electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To reduce cost without requiring an exclusive power source, simultaneously, to obtain a stable chute bias voltage without inhibiting the function of a corothoron and further, to apply the voltage to the corothoron to which an alternating current is applied by grounding the shield of an AC system corothoron via a constant voltage element having a rectifying action and electrically connecting the shield with the chute part of a paper sheet feeder. CONSTITUTION:The direct current of the same polarity as a transfer polarity and an alternating current are applied to the corothoron wire 9 of a transfer- peeling integrated type corothoron 22 and the corothoron 23 respectively. The shield 24 of the transfer-peeling integrated type corothoron 22 is grounded via the constant voltage element 25 using a Zener diode and moreover, chutes 14 and 15 and a guiding plate 16 are connected to the shield 24. The original functions of the discharge current of the corothoron wire 9, a shield voltage, etc., with respect to the load fluctuations of the chute part in this constitution are normally worked. A bias voltage acts on the chutes 14 and 15 and the guiding plate 16 as a chute voltage.

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 opposite to each other, and a paper supply device 8 is provided toward the transfer device 5. 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 been conventionally made as measures against the above-mentioned water-containing transfer failure, the main ones of which are shown in FIG. 1, and further, JP-A-1-27417.
1, JP-A-61-240265, JP-A-61-36.
776 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. In this configuration, as shown in FIG. 3, the corotron discharge current A and the shoot bias voltage B change as the load resistance of the chute changes, and the shoot bias voltage greatly changes as the load of the chute 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 change in the load resistance of the chute portion in this case is as shown by C in FIG. It is very unstable because of a large change in temperature, 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 in view of the above, and has been made in order to solve the drawbacks of the prior art in which a shoot bias is obtained using a corotron, and it is inexpensive without requiring a dedicated power source. In addition, it is possible to obtain a stable shoot bias voltage without hindering the function of the corotron, further applicable to a corotron to which an alternating current is applied, and to supply a stable half-wave rectified voltage to the chute, and further It is an object of the present invention to provide an image forming apparatus for an electronic copying machine which can save space.

[0010]

In order to achieve the above object, an image forming apparatus for an electronic copying machine according to the present invention is, in the first invention, a transfer / separation integrated corotron (T / DTC),
The shields 24 and 27 of an AC corotron such as a copy auxiliary corotron (PTC) are grounded via a constant voltage element 25 having a rectifying action, and the shields 24 and 27 are electrically connected to the chute portion of the paper feeding device 8. It has been configured. In the second invention, a part of the shield 27 of the transfer assisting corotron 26 also serves as a part of the upper chute of the sheet feeding device 8. In the third invention,
The shield of the AC corotron on which the same DC as the transfer polarity is superimposed is grounded via a parallel circuit of the constant voltage element 25 and the capacitor 28 having a rectifying function, and the shield and the chute portion of the paper feeding device 8 are electrically connected. It is configured to be connected physically.

[0011]

[Operation] In the first and second inventions, the shield of the corotron is half-wave rectified, and in the third invention, the rectified and smoothed self-bias of a constant voltage acts, and this bias voltage is applied to the sheet feeding device. 8 shoots.

[0012]

[Embodiment] FIG. 6 to FIG. 10 of the first embodiment of the present invention.
It will be described based on. In the description of this embodiment,
The same members as those of the conventional example shown in FIGS. 1 to 5 are designated by the same reference numerals and the description thereof will be omitted. The transfer device 5 and the peeling device 6 form an integrated transfer / peeling type corotron 22, in which the corotron wire 9 is supplied with direct current having the same polarity as the transfer polarity, and the corotron 23 is supplied with alternating current. It is applying. And this transfer / release integrated corotron 22
The shield 24 is grounded via a constant voltage element 25 using a Zener diode, and the shoots 14, 1
5 and the guide plate 16 are connected to the shield 24. The guide plate 16 is insulated from the shield 23.

The discharge current and the shield voltage of the corotron wire 9 with respect to the load fluctuation of the chute portion in this configuration are as shown in FIG. 7, and E in the figure is an alternating current of the corotron wire 9 of the transfer / separation integrated type corotron 22. , F indicates a direct current, and G indicates a shield voltage, respectively, which shows that the original function of the corotron in the practical range is operating normally. Further, a concrete output waveform in this configuration is as shown in FIG. 8, and H in the figure is an applied voltage waveform when the corotron wires 9 and 23 of the integrated transfer / separation type corotron 22 are mixed. Are offset by the superposition of. At this time, the constant current element 25
Thus, a half-wave rectified self-bias of a constant voltage indicated by I in the figure is obtained on the shield 24, and this bias voltage acts on the shoots 14 and 15 and the guide plate 16 as a shoot voltage. Further, the same effect can be obtained in the AC corotron in which the corotron 22 has the transfer polarity and the reverse polarity superposed on each other like the transfer assisting corotron.

FIG. 9 shows a modification of the first embodiment. In order to prevent toner stains on the guide plate 16 in the vicinity of the photoconductor 1, this guide plate 16 is independently used as a constant voltage element. An example of grounding via 25a is shown.

In the above embodiment, the shield 24 of the transfer / separation integrated type corotron 22 is grounded via the constant voltage element 25, and the half-wave rectified constant voltage self-bias obtained by the shield 24 at this time is shot 14. , 15 and the guide plate 16, but as shown in FIG. 10, in the case of the electronic copying machine having the transfer assisting corotron 26 on the upstream side of the transfer portion, this transfer assisting corotron 2
The shield 27 of No. 6 may be grounded via the constant voltage element 25, and the shoots 14, 15 and the guide plate 16 may be connected to this shield 27. In this structure, part of the shield 27 of the transfer assisting corotron 26 is used as part of the upper chute 15.

Next, a second embodiment of the present invention will be described with reference to FIGS. 11 to 14 and only differences from the first embodiment. A constant voltage element 25 having a rectifying function such as a zener diode (or a varistor) and a capacitor 28 are connected in parallel to the shield 24 of the transfer / separation integrated corotron 22, and the shield 24 shoots. 14, 15 and guide plate 16
It is connected to the.

FIG. 12 shows changes in the shoot bias voltage and the corotron discharge current with respect to changes in the load of the shoot section in this configuration. In the figure, J indicates an alternating current of the corotron wire 9, K indicates a direct current, and L indicates a shield voltage. Further, the specific output waveform in this configuration is as shown in FIG. 13, where M is the corotron wire 9
This is a mixed output waveform of the corotron wire 9,2.
It is offset by the DC voltage applied to 3.
At this time, a constant voltage self-bias rectified and smoothed on the shield 27 is obtained by the circuit of the constant voltage element 25 and the capacitor 28, and the stabilizing bias voltage indicated by N in the figure is applied to the shoots 14 and 15 and the guide plate 16. To work.

FIG. 14 shows another embodiment of the present invention. In order to prevent toner stains on the guide plate 16 near the photoconductor 1, the guide plate 16 is independently provided with a constant voltage element 25b. An example of grounding is shown.

[0019]

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. It is possible to obtain a stable chute bias voltage, further applicable to a corotron to which an alternating current is applied, and to supply a stable half-wave rectified voltage to the chute, and further, it is possible to achieve space saving. INDUSTRIAL APPLICABILITY According to the present invention, the guide plate 16 and the chutes 14 and 15 provided near the photoconductor 1 can be applied to an AC system corotron.
Can be integrated with the transfer assisting corotron, and it is possible to obtain effects such as space saving and no need for insulation. Moreover, it can be applied to an alternating current corotron of opposite polarity.

[Brief description of drawings]

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

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

FIG. 3 is a diagram showing changes in shoot bias voltage and corotron discharge current with respect to load fluctuations 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 shoot bias voltage and corotron discharge current with respect to load fluctuations in a third conventional example.

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

FIG. 7 is a diagram showing changes in a shoot bias voltage and a corotron discharge current with respect to a load change in the first embodiment 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 an example of an electronic copying machine having a transfer assisting corotron in the first example of the present invention.

FIG. 11 is an explanatory diagram showing a second embodiment of the present invention.

FIG. 12 is a diagram showing a shoot bias voltage and a corotron current with respect to a load change in the second embodiment of the present invention.

FIG. 13 is a diagram showing waveforms of voltage and shoot bias voltage of a corotron wire in the second example of the present invention.

FIG. 14 is a structural explanatory view showing a modification of the second 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, 4 ... 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 ... Corotron with integrated transfer and peeling, 2
3 ... Peeling corotron wire, 25, 25a, 25b ... Constant voltage element, 26 ... Transfer assisting corotron, 28 ... Capacitor.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 10, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 12

[Correction method] Change

[Correction content]

[Fig. 12]

Claims (3)

[Claims] 1. A corotron integrated with transfer and peeling (T / DT)
C), the shields 24 and 27 of an AC system corotron such as a transfer assisting corotron (PTC) are grounded via a constant voltage element 25 having a rectifying action, and the shields 24 and 27 are also grounded.
An image forming apparatus for an electronic copying machine, characterized in that a chute portion of a sheet feeding device 8 is electrically connected. 2. A shield 27 of the transfer assisting corotron 26.
2. An image forming apparatus for an electronic copying machine according to claim 1, wherein said shield 27 is electrically connected to a ground via a constant voltage element 25, and a chute portion is electrically connected to said shield 27. An image forming apparatus for an electronic copying machine, which is also used as a part of the chute. 3. Corotron integrated with transfer and peeling (T / DT
C), the shield of an AC system corotron such as a transfer auxiliary corotron (PTC) is grounded via a parallel circuit of a constant voltage element 25 having a rectifying action and a capacitor 28, and the shield and the chute part of the paper feeding device 8 are connected. An image forming apparatus for an electronic copying machine, which is electrically connected.