JPS60201332A - Original platen of copying machine - Google Patents

Abstract

PURPOSE:To set even a thin original on original platen glass without any position shift by providing an electrostatic attracting device to the original platen of the copying machine. CONSTITUTION:A couple of electrodes 26 and 28 of the electrostatic attracting device are formed in a comb shape and distributed uniformly over the entire surface of the original platen glass at nearly equal distance. A transparent insulating layer 30 covers the original platen glass including the couple of electrodes 26 and 28, which are connected to a power source 34 through a switch 32 provided on the top switch button board 18 of the copying machine frame. The transparent electrodes 26 and 28 are made of, for example, silver and the insulating layer 30 may be formed of transparent resin or transparent glass. The transparent electrodes are not made completely transparent as long as silver, etc., are used, but a copy is taken only by adjusting the development density of the copy when the transmissivity for exposure is >=70%.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a copying machine, and more specifically, to a document placement platen of a copying machine.

Prior Art Conventional electronic copying machines normally lift the platen cover above the document placement platen, place the document on the document placement platen, then lower the platen cover and set the document on the document placement platen. are doing. Otherwise, the document is set in a so-called document handler, the document handler feeds the document onto a document placement platen, and the document is set on the document placement platen.

With the method described above, relatively thick originals can be placed in the desired position on the document placement platen and the expected copies can be made, but relatively thin originals often cannot be copied as expected. I can't take it.

Specifically, when a thin original is placed on the original placing platen and the platen cover is lowered, the thin original is fanned by the platen cover and floats up, causing the original to shift by the time the platen cover is completely lowered. This results in a copy with a misaligned image.

In addition, so-called document handlers can only handle relatively thick originals, and if a relatively thin original is placed in the document handler, the feed roller will roll up the original when the document handler feeds the original onto the document placement platen. The original may become wrinkled or wrinkled, making it impossible to place the original on the original platen.

OBJECT OF THE INVENTION Therefore, the present invention provides a document placement platen for a copier that solves the above-mentioned problems with the conventional copier and the document handler used in combination with the copier, and allows a thin document to be set correctly. This is what I am trying to do.

According to the structure of the invention, that is, according to the present invention, an electrostatic adsorption device is provided on a document placement platen of a copying machine.

If an electrostatic attraction device is provided on the document placement platen in this manner, when a document is placed on the document placement platen, the document is attracted by the electrostatic attraction device and held on the document placement platen. Therefore, when the platen cover is lowered, the thin document will not be fanned by the platen cover and a portion of it will not be lifted up.

Therefore, from the time the platen cover is lowered until it is completely lowered, the thin original will not be fanned by the platen cover, which will cause the original to be set out of alignment. Therefore, the image will be in the correct position. You can make a copy.

As mentioned above, the electrostatic adsorption device exerts a strong adsorption force against the force that acts in the direction of peeling off the adsorbed document. You can do things freely. Therefore, after placing the original on the original placing platen, there is no problem in shifting and adjusting the position of the original.

Note that the electrostatic adsorption device may be provided on the entire surface of the document placement platen. In this case, the electrostatic adsorption device includes a pair of transparent electrodes that are formed so as to be distributed over the entire surface of the plate glass of the document placement platen and are spaced apart from each other, and a plate glass that covers the transparent electrodes. It can be configured to include a transparent insulating layer covering the entire surface.

However, instead of uniformly distributing the electrostatic chuck electrodes over the entire surface of the document placement platen, the electrostatic chuck electrodes of the electrostatic chuck device may be distributed at appropriate intervals.

Further, instead of providing the electrostatic adsorption device on the entire surface of the document placement platen glass, the document position example of the document placement platen glass may be formed in a band shape along the side.

In this case, the electrostatic adsorption device has a pair of electrodes spaced apart from each other over a band-shaped range along the sides of the document placement platen glass, and a plate glass plate that covers the transparent electrodes. It can be configured to include an insulating layer that covers at least the band-shaped range. In this case, the electrode may be formed of an opaque conductive material and the insulating layer may be formed of an opaque insulating material, or the electrode may be formed of a transparent conductive material and the insulating layer may be formed of a transparent insulating material. It may be made of material.

Embodiments Hereinafter, embodiments of a document placement platen for a copying machine according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view of an electronic copying machine that can be equipped with a document placement platen according to the present invention. The illustrated copying machine has two paper feed cassettes 12 and 1 on one side of the copying machine main body 10.
4 is attached, and a copy tray 16 is attached to the other side. Furthermore, a switch button board 18 and a document placement platen glass 20 are provided on the top surface of the copying machine main body. An indication plate 2 has a document position with the document size graduated along one side of the document placement Braden glass 20.
2 is installed. Furthermore, a platen cover 24 is hinged along the rear side of the copying machine main body and along one side of the document placement platen glass 20.

On the original platen glass 20 of the copying machine as described above,
According to the present invention, an electrostatic chuck electrode of an electrostatic chuck device is formed in a pattern as shown in FIG. In the case of FIG. 2, the pair of electrodes 26 and 28 of the electrostatic adsorption device are formed in a comb shape as shown by dotted lines, and are uniformly distributed over the entire surface of the document placement platen glass 20, and are spaced approximately equidistant from each other. It is located. As shown in the partial cross-sectional view of FIG. 3, a transparent insulating layer 30 covers the original platen glass so as to cover the pair of electrodes 26 and 28. Additionally, the electrodes 26 and 28 are connected to a power source 34 via a switch 32. This switch 32 is provided on the switch button board 18 on the top surface of the copying machine body described above.

Examples of materials that can be used for the transparent electrodes 26 and 28 include silver, gold-germanium alloy, and aluminum.

Further, the insulating layer 3 (+) may be made of transparent resin or transparent glass.

The material of the transparent electrode is silver, gold-Germany 911 alloy,
As long as aluminum is used, it cannot be made completely transparent. However, the transmittance of the exposure light of the copying machine is 70.
% or more, the exposure light is applied twice: once when it goes to the document, and once when it is reflected from the document.

Even if it passes through the electrode, a transmittance of almost 50% can be ensured, so
By simply adjusting the developing density of copies, you can make copies that are completely the same as before. And the current transmittance is 70
% or more transparent electrodes can be easily realized.

Further, the electrostatic attraction of the electrostatic attraction device is due to the action of an electric field that passes through the transparent insulating layer from the electrode and acts on the document. Therefore,
In order to strengthen the electric field protruding onto the upper surface of the document placement platen glass and increase the electrostatic adsorption force, the voltage of the power supply 34 should be increased, and at the same time, the transparent insulating layer should be formed as much as possible to ensure electrical insulation. It is preferable to make the thickness 30 thin.

When the voltage of the power source 34 was 500 volts and the thickness of the transparent insulating layer 30 was 100 microns, sufficient electrostatic attraction force could be obtained.

Note that the power supply 34 may be a DC voltage power supply or an AC voltage power supply.

The copying machine equipped with the document placement platen according to the present invention described above can be used as follows.

Open the platen cover 24 and place the original on the original placing platen glass 20. The switch 32 may be closed before this time, or it may be closed after the document is placed. When a voltage is applied between the electrodes 26 and 28, the original is electrostatically attracted to the original platen glass 20 by the electric field acting between the electrodes. If the original is misaligned, shift the original and adjust the position. As described above, the electrostatic adsorption force exerts a shallow resistance to the peeling force acting perpendicularly to the original platen glass 20. along the surface of −(
If you don't shift the original, it won't be much of a hindrance.

After that, the platen cover 24 is lowered. At this time, the document is held by electrostatic attraction on the document placement platen glass by the electrostatic attraction device, so that it does not shift at all. Next, the copy button on the switch button board 18 of the copying machine main body 10 is pressed to make a copy.

When copying is finished, the original can be easily peeled off from the original platen glass by opening the platen cover 24 and opening the switch 32. Note that if the switch 32 is kept closed, the document can be removed from the platen glass 20 by pulling it out along the document placement platen glass 20.

By distributing electrodes in the pattern shown in FIG. 2 on the original platen glass, any size original can be held by electrostatic attraction. However, the electrostatic attraction force to the extent that the document does not shift when the platen cover 24 is lowered can be obtained without distributing electrodes over the entire surface of the document placement platen glass.

For example, as shown in FIG. 4, the electrodes 26 and 28 may be arranged in a plurality of groups, for example four groups 36, 38, 40, 42.

Furthermore, as shown in No. 51 No. 1, the document positioning is done using the instruction plate 2.
Original platen glass 2 on the side where 2 is visible
Electrodes 26 and 2 are placed only in a narrow narrow area along one side of 0.
8 may be placed. In this case, since the periphery of the document is normally left blank, the electrodes 26 and 28 and the covering insulating layer 30 thereon may be made of an opaque material. However, since there are cases where there are letters and pictures even in the green color of the document, even in the embodiment of FIG. 5, it is preferable that the electrodes 26 and 28 and the covering insulating layer 30 thereon be made of an opaque material.

Furthermore, in the embodiment of FIG. 5, when the electrodes 26 and 28 and the overlying insulating layer 30 are formed of an opaque material,
Instead of providing the electrode of the electrostatic adsorption device on the document placement platen glass, a band-shaped electrostatic adsorption plate is used in which an electrostatic adsorption electrode is arranged between the document position indication plate 22 and the document placement platen glass 20. You may also place .

In addition, in the above-described embodiment, three types of patterns of the electrostatic chuck electrode were revealed, but the pattern of the electrostatic chuck electrode is not limited to these, and the pattern of the electrostatic chuck electrode is not limited to these, and it generates an electrostatic field on a necessary part of the document placement platen glass. Any pattern may be used as long as it is possible.

Additionally, it will be apparent to those skilled in the art that the document placement platen of the present invention is applicable to any copying machine that has a document placement platen.

Effects of the Invention As is clear from the above description, if the document placement platen of the present invention is provided in a copying machine, even a thin document can be set on the document placement platen glass without causing any positional deviation.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a copying machine equipped with the document placement platen of the present invention, and FIG. 2 is an example of an electrode pattern of an electrostatic adsorption device provided on the document placement platen glass according to the present invention. 3 is a partial sectional view of the original platen glass shown in FIG. 2, and FIG. 4 is another electrode pattern of the electrostatic adsorption device provided on the original platen glass according to the present invention. FIG. 5 is a diagram showing still another example of the electrode pattern of the electrostatic adsorption device provided on the document placement platen glass according to the present invention. [Main reference numbers] 10. Copying machine body, 12.14. Paper cassette, 1
6. Copy tray, 18. Switch button board, 20. Original platen glass, 22. Indication plate with document position, 24. Platen cover, 26. 28. Electrode, 30.
・Insulating layer, 32... Switch, 34... Power supply patent applicant Hiroyo Shimizu Attorney Patent attorney Masahiko Arai

Claims (7)

[Claims] (1) A copying machine characterized in that an electrostatic adsorption device is provided on the document placement platen. (2) The copying machine according to claim 1, wherein the electrostatic adsorption device has a pair of electrodes distributed over the entire surface of the document placement platen. (3) The electrodes of the electrostatic adsorption device are composed of a pair of transparent electrodes that are formed so as to be distributed over the entire surface of the plate glass of the document placement platen and that are spaced apart from each other, and cover the transparent electrodes. 3. The copying machine according to claim 2, wherein the transparent insulating layer covers the entire surface of the sheet glass. (4) The electrostatic adsorption device is characterized in that the document positioning device of the document placement platen glass has a pair of electrodes arranged in a band shape along the side of the document placement platen glass. Copying machine mentioned. (5) The electrodes of the electrostatic adsorption device are composed of a pair of electrodes that are spaced apart from each other over a band-shaped range along the sides of the document placement platen glass, and are arranged so as to cover the transparent electrodes. 5. The copying machine according to claim 4, wherein the insulating layer covers at least the band-shaped area of the sheet glass. (6) The copying machine according to claim 5, wherein the electrode is made of an opaque conductive material, and the insulating layer is made of an opaque insulating material. (7) The copying machine according to claim 5, wherein the electrode is made of a transparent conductive material, and the insulating layer is made of a transparent insulating material.