Electrostatic transmission mechanism

Abstract

An electrostatic transmission mechanism can be adopted for use in data media recorders such as printers, facsimile machines, or scanners to transport media. The invention has a feed roller with an electrostatic field generator located therein to generate static electricity on the surface of the feed roller to attract and transport media. The invention can eliminate the disadvantages of conventional transmission mechanisms such as crumpled paper resulting from the pressing of the feed rollers, star wheel tracks on the paper caused by the star wheels, etc.

Description

FIELD OF THE INVENTION

[0001] The invention relates to a transmission mechanism adopted for use in data media recorders such as printers, plotters, scanners, Multi-Function Peripherals (MFP, Copiers) and the like, and particularly to a transmission mechanism that utilizes static electricity to transport papers.

BACKGROUND OF THE INVENTION

[0002] Data media recorders are very popular these days. The equipment to print media data on paper or to convert media data on paper to digital data for storage includes printers (Inkjet, Laser, or Impact printers), plotters, scanners, and Multi-Function Peripherals (MFP, Copiers). These all need a transmission mechanism to transport the media (paper), whether feeding (delivering paper), printing (scanning) on the middle frame, or discharging (paper).

[0003] The current data media recorders being used in printers mostly adopt feed rollers, deflators or star wheels to transport the media for feeding, printing or discharging. Although these mechanisms aim at conveying or positioning the media in a flat manner, printing quality is still not desirable. For instance, papers transported by two feed rollers become crumpled (as shown in FIG. 1A). The discharging mechanisms that use star wheels 6 leave star wheel tracks on the paper and seriously affect the printing quality (referring to FIG. 1B).

[0004] There are other paper feeding mechanisms that employ gear transmission. In order to match the size of the paper, and to make the paper flat and smooth in the entire conveying process, the size of the mechanism becomes substantially larger (as shown in FIG. 1C), which incurs higher costs. Moreover, transmission mechanisms used in plotters employ air fans to create vacuum suction to place the paper on the printing middle frame, which generates substantial noise.

SUMMARY OF THE INVENTION

[0005] The object of the invention is to provide an electrostatic transmission mechanism to resolve the aforesaid disadvantages. The invention employs static electricity to attract media onto the feed roller in a flat and smooth manner to achieve high quality printing and to transport or re-direct the media.

[0006] The electrostatic transmission mechanism of the invention is adopted on various data media recorders for media feeding, printing and discharging in static printing operations and also for dynamic transporting. The transmission mechanism includes a feed roller and an electrostatic field generator. The electrostatic field generator generates a reaction on the feed roller and produces static electricity on the roller surface. Therefore the feed roller can transport the media without employing the complicated conventional designs of feed rollers or star wheels. Cost can be dramatically reduced and printing quality can also be improved.

[0007] The electrostatic field generator is formed by laying conductive wires on the feed roller surface. A single circuit wiring is used to form two conductors to connect respectively to two poles. The surface is coated with an insulation layer. Through deploying different types and densities of wiring configuration and different widths of insulation, power intensity generated by the electrostatic field generator may be controlled to enable the feed roller to generate different electrostatic attraction forces to transport or re-direct the media.

[0008] The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIGS. 1A-1C are schematic views of disadvantages of conventional transmission mechanisms;

[0010] FIG. 2 is a schematic view of the invention;

[0011] FIGS. 3A-3C are schematic views of wiring configurations of the invention;

[0012] FIG. 4 is a schematic view of the invention, adopted on a printing middle frame;

[0013] FIG. 5 is a schematic view of the print head and the paper, according to FIG. 4;

[0014] FIG. 6 is a schematic view of the invention, adopted on a paper discharging mechanism; and

[0015] FIGS. 7A, 7B and 8 are schematic views of the invention, showing re-direction of paper transportation.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016] The electrostatic transmission mechanism of the invention includes a feed roller and an electrostatic field generator. The electrostatic field generator generates a reaction on the feed roller and produces an electrostatic field on the roller surface. Therefore the feed roller can attract the media to be transported. Through the rotation of the feed roller, the media may be moved as desired. An electrostatic field may be generated by many methods. The following depicts one embodiment for elaboration of the invention.

[0017] Referring to FIG. 2, a feed roller 10 has its surface coated or taped with conductive wires 21. The conductive wires 21 are coated and covered by an insulation layer 22. Conductive wires 21a and 21b cross each other and connect to a positive pole and a negative pole (not shown in the drawing) of a power supply. The wiring configuration may be a band shape (as shown in FIG. 3A), a wave shape (as shown in FIG. 3B), or a saw shape (as shown in FIG. 3C). The wiring may be parallel with the spindle direction of the feed roller 10, or form an angle with the spindle direction. In principle, the conductive wires 21a and 21b must be crossed with each other to generate the electrostatic field on the surface of the feed roller 10. The intensity of the electrostatic field is controlled by different types and densities of the wiring configuration and different widths of insulation layer 22. Designs of the wiring configuration, in addition to considering the intensity of the electrostatic field, also depend on deploying environments, locations and utilization. And the intensity of the electrostatic field is also determined by the voltage difference output of the power supply.

[0018] When adopted on a printing middle frame as shown in FIG. 4, the feed rollers 11 and 12 have an electrostatic field and generate electrostatic force to attract a piece of paper 7 to their surfaces. Then the feed rollers 11 and 12 rotate to convey the paper 7. Such a design does not require that the paper is moved to a selected location behind the print head 2 as the discharging system of the conventional star wheel 6 does (comparing with FIG. 1C), so it does not need many intermediate transmission gears. As a result, the length of the printing middle frame may be shortened, and cost can be reduced. Noise generated by the intermediate transmission gears is also reduced. In addition, as the paper 7 is transported by a single feed roller 11 (12), paper crumpling can be avoided. Thus the paper 7 becomes flat and smooth. The gap G between the print head 2 and the paper 7 also may be shrunk (as shown in FIG. 5). As a result, printing quality may be improved (comparing with FIG. 1A).

[0019] By the same token, when deploying the invention on a paper discharging mechanism, the feed roller 12 with an electrostatic field attracts the paper 7 and discharges the printed paper 7. There is no press operation, as required by the star wheels 6. Hence the printed paper does not have the star wheel tracks that might otherwise occur when the star wheels 6 roll over the fresh printing data on the paper 7 (shown in FIGS. 1B and 6).

[0020] In addition, Referring to FIGS. 7A and 7B, the feed rollers 13 and 14 with static electricity generate a stretching force on the paper 7 and change the direction of paper movement. In other words, by deploying a roller seat 17 (as shown in FIG. 8) to encase and anchor the feed roller 14, and to form selected exposing areas on the feed roller 14, the feed roller 14 with static electricity can attract the paper 7. Then the rotating feed roller 14 can move the paper 7 to a selected location A, and the paper 7 leaves the feed roller 14. When the paper 7 reaches location B, the paper 7 bounces upwards due to its own tension. When the paper 7 reaches location C, it completely separates from the feed roller 14.

[0021] By means of the construction set forth above, the electrostatic transmission mechanism of the invention can generate static electricity on the feed roller through the electrostatic field generator for attracting and transporting the media. In addition, it provides the following functions:

[0022] 1. By employing the attraction of static electricity, the media on the printing middle frame is flat and smooth. The gap between the print head and the media may be reduced to improve printing quality.

[0023] 2. The length of the printing middle frame may be reduced to lower cost.

[0024] 3. The star wheel tracks produced by the star wheels in the paper discharging mechanism may be eliminated to improve printing quality.

[0025] 4. The media transporting mechanism requires fewer elements.

[0026] 5. The principle of attraction of static electricity of a single feed roller may be used for re-direction of the media without using multiple rollers.

[0027] 6. The intensity of the electrostatic field may be controlled by a single circuit, different configurations and density of wiring, and thickness of the insulation layer.

[0028] While the preferred embodiment of the invention has been set forth for the purpose of disclosure, modifications of the disclosed embodiment of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.

Claims

1. An electrostatic transmission mechanism for data media recorders to transport a paper through feeding, printing and discharging operations, comprising:

a feed roller driven to rotate by a driving apparatus of the data media recorders to transport the paper; and

an electrostatic field generator connecting electrically to the feed roller to generate static electricity on the surface of the roller to attract the paper and to allow the paper to move on the surface of the feed roller in a flat and smooth manner.

2. The electrostatic transmission mechanism of claim 1, wherein the electrostatic field generator includes:

a power supply which has a positive pole and negative pole; and

two pairs of conductive wires crossing with one another and being laid on the surface of the feed roller, and connecting respectively to the positive pole and the negative pole of the power supply for generating static electricity.

3. The electrostatic transmission mechanism of claim 2, wherein the conductive wires are covered by an insulation layer.

4. The electrostatic transmission mechanism of claim 3, wherein the intensity of the electrostatic field is determined by the thickness of the insulation layer.

5. The electrostatic transmission mechanism of claim 2, wherein the intensity of the electrostatic field is determined by the output voltage of the power supply.

6. The electrostatic transmission mechanism of claim 2, wherein the intensity of the electrostatic field is determined by the density of the conductive wires and wiring configurations of the conductive wires.

7. The electrostatic transmission mechanism of claim 2 further having a roller seat to control exposed areas of the feed roller and re-direction of the paper transportation.

8. An electrostatic transmission mechanism for data media recorders having a feed roller to transport media required by the data media recorders, characterized by:

two pairs of conductive wires crossing with one another and being laid on the surface of the feed roller and said conductive wires connecting to a power supply to generate static electricity on the feed roller to attract and transport the media.

9. The electrostatic transmission mechanism of claim 8, wherein the conductive wires are covered by an insulation layer.

10. The electrostatic transmission mechanism of claim 9, wherein the intensity of the electrostatic field is determined by the thickness of the insulation layer.

11. The electrostatic transmission mechanism of claim 8, wherein the intensity of the electrostatic field is determined by the density of the conductive wires and wiring configurations of the conductive wires.

12. The electrostatic transmission mechanism of claim 8 further having a roller seat to control exposed areas of the feed roller and re-direction of the paper transportation.