KR100474428B1 - a high voltage changeover equipment for a color laser printer - Google Patents

Abstract

The developing device high voltage switching device of the disclosed color image forming apparatus is a device for sequentially applying a high voltage to the color developing units for developing an electrostatic latent image formed on the photosensitive medium of the color image forming apparatus with color toner. In particular, the high voltage applying terminal is fixed to the photosensitive medium and having a constant developing gap (gap), respectively formed in the rear end of the developer for each color; A high voltage circuit board having a high voltage circuit embedded therein, and having a color terminal terminal connected to each of the high voltage applying terminals on one side thereof, and a color contact terminal connected to the high voltage circuit disposed on the other side thereof; Color high voltage connection means for connecting a color-specific contact terminal of the high voltage circuit board and the color terminal terminals to apply a high voltage to the corresponding color-developers. The high voltage connection means, the holder; A contact member having one side connected to the holder and the other side fixed to the high voltage circuit board and connected to the terminal terminal through a circuit inside the high voltage circuit board; And a holder flow member for advancing and retracting the holder toward the high voltage circuit board such that one side of the contact member selectively contacts the contact terminal.

Description

A high voltage changeover device for a color laser printer}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic color image forming apparatus, and more specifically, a high developing voltage (hereinafter, collectively referred to as 'high voltage') for development in a color-specific developing unit for developing an electrostatic latent image of a photosensitive medium with toner. The present invention relates to a high voltage switching device for developing.

For example, an electrophotographic color image forming apparatus such as a color laser printer or a copying machine sequentially uses an electrostatic latent image formed on a photosensitive medium by using a color developer, that is, a yellow toner developer, a magenta toner developer, a cyan toner developer, and a black toner developer. By developing, a visible color image is formed, which is then transferred onto a printing sheet and printed.

In the printing process as described above, the developing process adopts a method in which the toner of the developer is transferred to the photosensitive medium by a potential difference between the photosensitive medium and the developing device. For this purpose, a high voltage is sequentially applied to any one of the selected developing devices or four developing devices. You must do it.

A typical example of the developing device high pressure switching device employed in a general electrophotographic color formation apparatus is shown in FIGS. 1, 2A, and 2B.

1, 2A and 2B, reference numeral 80 denotes a photosensitive drum, 82 denotes a developer, and 83 denotes a driving device. Prior to the description, as shown in FIG. 1, a general color image forming apparatus includes four developing devices for each color, but since the four developing devices have the same structure and operation, only one developing device is used for convenience of description. Explain.

As shown in FIG. 1, the four developing units 82 are provided to selectively or sequentially approach the photosensitive drum 80. Each of these developing units 82 includes a developing roller 90 and a toner supply roller 92, as shown in Figs. 2A and 2B.

FIG. 2A shows a state before the high voltage is applied to the developer 82 or a state where the high voltage is applied to the developer 82, and FIG. 2B shows that the high voltage is applied to the developer 82 so that the toner in the developer 82 is photosensitive. It is a figure which shows the state which develops at 80. FIG. As can be seen in the figure, the driving device 83 includes a motor 86 and a cam 84, and is disposed on the rear end side of each developing unit 82. The driving unit 83 moves the corresponding developer 82 back and forth toward the photosensitive drum 80 so that the developing roller 90 approaches the photosensitive drum 80 so that the toner of the developing roller 90 is exposed to the photosensitive drum 80. To be transported).

On the other hand, the high voltage terminal 88 for generating a potential difference required for development in the photosensitive drum 80 and the developing roller 90 is fixed to a frame (not shown). Therefore, when the developing unit 82 is advanced toward the photosensitive drum 80 by the driving device 83, the high voltage is applied to the developing roller 90 while the shaft of the developing roller 90 and the high voltage terminal 88 are in contact with each other. It is applied and the toner of the corresponding developer 82 is transferred to the photosensitive drum 80 (see Fig. 2B).

Thereafter, the developing unit 82 is retracted by the return spring 94 provided at the rear end thereof (see FIG. 2A), and the development by the toner of a different color is performed while the other developing unit is advanced by the driving of the driving device. In this series of continuous operations, the developer for each color flows sequentially to develop the electrostatic latent image of the photosensitive drum 80 with color toner.

However, the general developing device high voltage switching device employed in the color image forming apparatus as described above uses the driving device 83 composed of the motor 86 and the cam 84 to move the developing device 82 to the photosensitive drum 80 side. In the forward and backward manner, not only vibration caused by the flow of the developer is induced, but also the developer periodically approaches and retracts the photosensitive drum, thereby causing a load change during the rotation of the photosensitive drum. These factors ultimately cause a change in the speed of the photosensitive drum, which causes jitter (JITTER) that is fatal to image quality, which is the life of color images.

In addition, in the conventional developing device flow type high voltage switching device as described above, a stable image quality can be obtained while maintaining a suitable developing gap only when the developing device has a constant flow distance, but the aging of the driving device 83 when used for a long period of time. As the flow distance of the developing device changes due to wear and the like, the quality of the image may be deteriorated because the developing device does not maintain a constant developing gap.

In addition, the conventional high voltage switching device of the developer requires a motor, a cam required for the developer flow, and a component such as a home sensor for sequentially driving the developer for each color, so that the manufacturing cost cannot be avoided. have.

The present invention has been made in view of the above problems, and employs a developer fixing method of sequentially applying a high voltage to each developing unit while the developing unit is fixed, thereby reducing the load variation of the photosensitive drum caused by the conventional developing unit flow method. SUMMARY OF THE INVENTION An object of the present invention is to provide a high voltage switching device for a developer of a color image forming apparatus which can prevent a deterioration of image quality.

Further, another object of the present invention is to provide a developing device high voltage switching device of a color image forming apparatus, such that even when the high voltage switching device is used for a long time, deformation of the contact member does not occur and stable high voltage is always applied.

It is another object of the present invention to provide a developer high voltage switching device of a color image forming apparatus which is simple in structure and reliably applies high voltage to each developer and can be switched, thereby improving reliability and reducing manufacturing costs.

The developing device high voltage switching device of the color image forming apparatus for achieving the above object of the present invention is a developing device high voltage switching device for supplying a voltage to each color developing device, the high voltage applying terminal formed on one side of the fixed color developing devices. field; A high voltage circuit board to which high voltage is applied; And high voltage connecting means for selectively connecting the high voltage applying terminal and the high voltage circuit board to a high voltage to the color developing devices. The terminal may further include a contact terminal and a terminal terminal to which a high voltage is not applied, and further comprising a spring terminal connecting the terminal terminal and the high voltage applying terminal. The high voltage connection means may include the contact terminal and the terminal. It is preferable to apply a high voltage to the color-specific developing device by selectively contacting the terminals. Therefore, by supplying a high voltage to the high-voltage applying terminal which is fixed to the color developing device and fixed to one side of each developing device by a high voltage applying means. Poor phenomenon occurs due to vibration of the developer . Does not Furthermore, the high voltage developing device switching apparatus of a color image forming apparatus of the present invention is a developing device a high voltage switching device to supply a voltage to the color-developing device, a high voltage circuit board is applied with a high voltage; A plurality of terminal terminals provided on the high voltage circuit board; A plurality of high voltage applying terminals provided at one end of the color developing device; a plurality of spring terminals connecting the terminal terminal to the high voltage applying terminal; And high voltage connecting means for selectively applying a voltage to the terminal terminal to selectively supply a high voltage to the color developing device. The high voltage connecting means includes: a holder; A contact member having one side connected to the holder and the other side connected to the terminal terminal; And a holder flow member for advancing and retracting the holder toward the contact circuit board. The contact member may be configured such that an upper end connected to the holder has a ring shape, and a lower end is connected to the terminal terminal. The color image forming apparatus of the present invention includes a photosensitive medium; Color-developers which are fixed to the photosensitive medium with a constant developing gap and develop electrostatic latent images formed on the photosensitive medium by color toner; A high voltage circuit board to which high voltage is applied; A plurality of terminal terminals provided on the high voltage circuit board; A plurality of high voltage applying terminals provided at one end of each color developing device; A plurality of spring terminals connecting the terminal terminal and the high voltage applying terminal; And high voltage connecting means for selectively applying a voltage to the terminal terminal to selectively supply a high voltage to the color-specific developing device. The high voltage connecting means includes: a holder; A contact member having one side connected to the holder and the other side connected to the terminal terminal; And a holder flow member for advancing and retracting the holder toward the high voltage circuit board such that one side of the contact member selectively contacts the contact terminal.

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Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view showing an embodiment of a high voltage switching device of the color image forming apparatus of the present invention, and shows only the yellow developer high voltage switching device for the convenience of description among the color-specific high voltage switching devices having the same structure.

In addition, FIG. 4 is a view illustrating all of the high voltage switching devices applying high voltage to each color developing device in the high voltage switching device of the color image forming apparatus of the present invention in FIG. 3, so that each of the four high voltage switching devices can be represented. The solenoid is removed and shown.

In the high voltage switching device of the color image forming apparatus of the present invention, a developer, that is, a yellow developer, a magenta developer, a cyan developer, and a black developer, is fixed in a non-contact manner with a photosensitive medium with a constant developing gap. A developing gap, which is an interval between the developing devices and the photosensitive medium, is usually maintained at about 200 μm, but is not limited thereto.

Hereinafter, a high voltage switching device for the yellow developing unit 28a will be described, and the remaining colors are also configured in the same manner. That is, the high pressure applying terminal 26a is formed at the rear end of the yellow developer 28a shown in FIG. 3, and the high pressure applying terminal 26a is formed at the rear end of each of the remaining color developing units.

As shown in FIG. 3, the yellow developer 28a is fixed to the photosensitive medium 27 with a constant developing gap, and the high voltage circuit board 20 is disposed behind the developer 28a. The high voltage circuit board 20 includes a high voltage circuit (not shown). A terminal terminal 30a is installed at a lower end of one side, and a contact terminal 22a is fixed at an upper end of the opposite side. have.

The contact terminal 22a is connected to a high voltage circuit (not shown) embedded in the high voltage circuit board 20. The terminal terminal 30a is also connected to a high voltage applying terminal formed at a rear end of a color-development developer. Of course, four are installed in the high voltage circuit board 20.

As shown in FIG. 4, holes 21a, 21b, 21c, and the lower ends of the contact terminals 22a, 22b, 22c, and 22d fixed to the upper end of one side of the high voltage circuit board 20 at a predetermined distance, 21d is formed, and bosses 32a, 32b, 32c, and 32d of the color image forming apparatus frame are provided so as to project through the holes 21a, 21b, 21c, and 21d.

Although the high voltage applying terminal 26a formed at the rear end of the yellow developing device 28a of FIG. 3 and the terminal terminal 30a installed at the lower end of one side of the high voltage circuit board 20 may be directly connected to each other, As such, it is preferably connected by a spring terminal 24a. The spring terminal 24a is excellent in elasticity to absorb shocks that may be transmitted from the high voltage circuit board 20 so as not to reach the developer 28a.

The high voltage connecting means 14a is composed of four so as to apply a high voltage to the developer for each color. As shown in FIG. 3, the high voltage connecting means 14a is disposed at the rear of the high voltage circuit board 20, and the holder 16a and the leaf spring. 18a, a solenoid 15a for advancing and reflowing the holder 16a to the high voltage circuit board 20 is provided.

One end of the leaf spring 18a is connected to the holder 16a, and the other end of the leaf spring 18a is fixed to the high voltage circuit board 20. The other side of the leaf spring 18a is connected to the terminal terminal 30a through a circuit (not shown) inside the high voltage circuit board 20.

The leaf spring 18a is an embodiment of a contact member for connecting the contact terminal 22a and the terminal terminal 30a, and the contact member may be any material as long as a high voltage can flow. It is preferable to comprise this excellent leaf spring 18a. As can be seen in the drawing, the leaf spring 18a has an upper end portion connected to the holder 16a in a bifurcated ring ring 34a shape, and the holder 16a is formed by the solenoid 15a. When the ring ring 34a is contacted with the contact terminal 22a of the high voltage circuit board 20, the contact property may be improved.

Further, the lower end of the leaf spring 18a is fixed to the high voltage circuit board 20 via a boss 32a of the image forming apparatus frame. As shown in FIG. 4, the leaf springs 18a are provided as many as the number corresponding to each contact terminal.

The solenoid 15a is one embodiment of a holder flow member for flowing the holder 16a. The holder flow member may be not only the solenoid 15a but also various other embodiments. Reference numeral 36 in FIG. 3 denotes a bracket 36a for supporting the solenoid 15a.

Hereinafter, the operation of the developer high voltage switching device of the color image forming apparatus according to the present invention configured as described above will be described with reference to FIGS. 3 and 5.

3 illustrates a state in which power is not applied to the solenoid 18a, that is, a state in which a high voltage is not applied to the corresponding developer 28a.

 As shown, the leaf spring 18a is retracted from the high voltage circuit board 20. Therefore, a high voltage is not applied to the developer 28a. In this case, the developing unit 28a is in an undeveloped state, and only one of the other three developing units except for the developing unit 28a is in a developing state. That is, the three other developers except for the developer in the developing state are not applied with the high voltage in the state shown in FIG. 3.

Thereafter, when the developing order of the developing unit in the undeveloped state is reached, power is applied to the solenoid 28a to advance the holder 15a toward the high voltage circuit board 20 side. Accordingly, as shown in FIG. 5, a portion of the upper non-ring ring 34a of the leaf spring 18a connected to the holder 16a is connected to the contact terminal 22a of the high voltage circuit board 20.

In FIG. 5, the arrow 38 is applied to the solenoid 28a so that the ring ring 34a portion of the upper end of the leaf spring 18a is connected to the contact terminal 22a of the high voltage circuit board 20. It shows the flow path of high voltage when high voltage is applied. That is, the terminal terminal 30a is energized from the contact terminal 22a of the high voltage circuit board 20 to the plate spring 18a, and is connected by a circuit embedded in the plate spring 18a and the high voltage circuit board 20 again. The high voltage is applied to the developing device 28a via the spring terminal 24a and the high voltage applying terminal 26a.

As described above, the high voltage application flow of the high voltage switching device may be summarized as follows.

1. Apply power to solenoid 28a

2. A portion of the ring ring 34a, which is the upper end of the leaf spring 18a, is connected to the contact terminal 22a of the high voltage circuit board 20.

3. High voltage is applied and high voltage is applied

4. Complete development of the developer

5. High voltage crackdown

6. Solenoid (28a) power interruption

7. A portion of the ring ring 34a, which is the upper end of the leaf spring 18a, retracts from the contact terminal of the high voltage circuit board 20.

8. Apply power to solenoid 28b of another developer

When the color image is printed as described above, the development of the corresponding color is completed in the order of the numbers 1 to 7, and the development of other colors is repeated by repeating the order of the numbers 1 to 7 again for the development of other developing devices. .

By repeating the above process, the electrostatic latent image formed on the photosensitive medium is developed into a visible color image. At this time, since the high voltage is sequentially applied to these developing apparatuses while the developer for each color is fixed in the developing process as described above, the problem of deterioration in image quality due to the load fluctuation of the photosensitive medium caused by the conventional developing method can be solved. have.

Since the developing device high voltage switching device of the color image forming apparatus of the present invention as described above can be configured by the developing device fixing method, it is possible to ensure stable image quality without changing the rotational speed and load variation of the photosensitive medium during development. .

In addition, according to the present invention, it is possible to eliminate components such as motors and cams as in the prior art for flowing the developing device, so that a high voltage switching device having a simple structure can be formed, and there is almost no development gap change between the developing device and the photosensitive medium. Defects can be prevented.

In addition, according to the present invention, by directly contacting using a solenoid, it is possible to minimize the high voltage section transmitted from the high voltage circuit board to each developer, and to minimize the contact point only by the contact between the contact terminal and the leaf spring, and as a direct contact The reliability of the high voltage contact is secured, so that high voltage can be stably applied to each color developing device, and ultimately, perfect color image quality can be realized.

Further, in the apparatus for applying a high voltage to four color color developing devices for implementing color printing, high voltage control for each developing device can be simply configured.

As described above and described with reference to a preferred embodiment for illustrating the principle of the present invention, the present invention is not limited to the configuration and operation as shown and described as such.

That is, the high voltage switching device of the present invention can be applied not only to color laser printers but also to various printers, copiers, multifunction devices, and the like which require sequential control of the developer applied voltage.

Also, those skilled in the art will appreciate that many modifications and variations of the present invention are possible without departing from the spirit and scope of the appended claims.

Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

1 is a cross-sectional view schematically showing a developer high voltage switching device employed in a general color image forming apparatus;

Figures 2a and 2b is a view showing a part to explain the structure and operation of the developing high voltage switching device shown in Figure 1, Figure 2a shows a state before the high voltage is applied to the developing device, Figure 2b is a high voltage is applied Enlarged cross section indicating status,

FIG. 3 is a diagram illustrating a developer high voltage switching device of a color image forming apparatus according to an embodiment of the present invention, and a side view showing a state before application of the high voltage of the yellow developer high voltage switching device among the same developer high voltage switching devices for each color; FIG.

4 is a view showing a developing device high voltage switching device of a color image forming apparatus according to an embodiment of the present invention, a perspective view showing the solenoid removed to show all the high voltage switching devices for each color;

FIG. 5 is a side view illustrating a state after high voltage application of the yellow developer high voltage switching device illustrated in FIG. 3.

<Description of the symbols for the main parts of the drawings>

14a: high voltage connection means 15a: solenoid

16a, b, c, d: holder 18a, b, c, d: plate spring

20: high voltage circuit board 22a, b, c, d: contact terminal

24a: Spring terminal 26a: High voltage terminal

27: photosensitive medium 28a: developing

30a: Terminal terminals 32a, b, c, d: Boss

21a, b, c, d; hole 34a: ring ring

36a: Bracket

Claims (9)

A developer high voltage switching device that supplies voltage to each color developer.  A high voltage applying terminal formed at one side of the color-specific developing devices that are fixed; A high voltage circuit board to which high voltage is applied; And high voltage connecting means for selectively connecting the high voltage applying terminals and the high voltage circuit board to a high voltage to the color developing devices. The method of claim 1, And the high voltage circuit board further comprises a contact terminal to which high voltage is applied and a terminal terminal to which high voltage is not applied. The method of claim 2, And a spring terminal for connecting the terminal terminal and the high voltage applying terminal. The method of claim 2, And the high voltage connecting means applies a high voltage to the color developing device by selectively contacting the contact terminal and the terminal terminal. A developer high voltage switching device that supplies voltage to each color developer. A high voltage circuit board to which high pressure is applied; A plurality of terminal terminals provided on the high voltage circuit board; A plurality of high voltage applying terminals provided at one end of each color developing device; A plurality of spring terminals connecting the terminal terminal and the high voltage applying terminal; And, And a high voltage connection means for selectively applying a voltage to the terminal terminal to selectively supply a high voltage to the color-specific developing device. The method of claim 5, wherein the high voltage connection means, holder; A contact member having one side connected to the holder and the other side connected to the terminal terminal; And a holder flow member for advancing and retracting the holder to the contact circuit board side. The method of claim 6, The contact member is a high voltage switching device of the color image forming apparatus, characterized in that the upper end connected to the holder is configured in a ring shape, the lower end is connected to the terminal terminal. Photosensitive medium; Color-developers which are fixed to the photosensitive medium with a constant developing gap and develop electrostatic latent images formed on the photosensitive medium by color toner; A high voltage circuit board to which high voltage is applied; A plurality of terminal terminals provided on the high voltage circuit board; A plurality of high voltage applying terminals provided at one end of each color developing device; A plurality of spring terminals connecting the terminal terminal and the high voltage applying terminal; And, And high voltage connection means for selectively applying a voltage to the terminal terminal to selectively supply a high voltage to the color-specific developing device. The method of claim 8, wherein the high voltage connection means, holder; A contact member having one side connected to the holder and the other side connected to the terminal terminal; And a holder flow member for advancing and retracting the holder toward the high voltage circuit board such that one side of the contact member selectively contacts the contact terminal.