JP2629780B2 - Electrostatic recording medium - Google Patents

Description

The present invention relates to an electrostatic recording medium suitable for use in a display device called an electronic blackboard, in which an electrostatic latent image is formed by discharging. The present invention relates to an electrostatic recording medium on which an image is formed by being converted into a visible image by post-toner.

[Summary of the Invention] The present invention relates to an electrostatic recording medium suitable for use in a display device called an electronic blackboard, and a toner after an electrostatic latent image is formed on a dielectric layer on a conductive layer by discharge. In an electrostatic recording medium on which an image is formed by converting to a visible image, the conductive layer or the base material is made white so that writing of the image on the medium is performed favorably. .

[Conventional technology]

2. Description of the Related Art Heretofore, there has been known an electronic blackboard for meetings having a function of hard-copying a character handwritten on a blackboard (whiteboard). With this electronic blackboard, even if you make a draft on paper, you need to handwrite it again on the blackboard and discuss it.If you can print the screen when the meeting ends halfway, Had to hand-write the same thing again.

For this reason, the present applicant has previously proposed an electronic blackboard with a display function capable of reading document information, writing it on a blackboard sheet, and displaying it (Japanese Patent Application No. 62-157176). As shown in FIG. 8, the electronic blackboard with a display function is arranged such that an electrostatic recording medium (1) as a blackboard board can be transferred endlessly via a feed motor (2) and a drive roller (3). I have. As shown in FIG. 10, this electrostatic recording medium (1) forms a conductive layer (1b) by depositing Al or the like on a base (1a) made of vinyl chloride, and forms a conductive layer (1b) on the conductive layer (1b). A dielectric layer (1c) made of polyvinylidene fluoride (PVDF) which contains titanium oxide and is white. In this case, the surface of the dielectric layer (1c) becomes the writing surface W.

On the back side of the endlessly arranged recording medium (1), a recording head (4) including a writing electrode, that is, a stylus electrode section (5) and a control electrode section (6), and an AC static eliminator (7).
, A cleaning blade (8), a CCD line sensor (10) having a lens system (9), a reflection mirror (11), and a developing device (12) for supplying toner.

The appearance of this electronic blackboard is shown in FIG.
The whole is covered with the cover (13), and the electrostatic recording medium (1) exposed from the window (13a) on the front surface of the cover (13) functions as a writing board. The cover (13) has a document insertion port (14), a discharge port (15), and a printout discharge port (16) for writing contents at the lower front part of the cover. Further, a leg (17) to which a caster (18) is attached is fixed to a lower end of the cover (13), so that the electronic blackboard is movable.

And when using this device as an electronic blackboard,
Writing is performed on the surface W of the recording medium (1) with, for example, a felt pen. When copying this, the recording medium (1) is transported, and the information written on the recording medium (1) on the back side of the apparatus is transferred to the CC via the reflection mirror (11).
Read with D sensor (10). Then, the image is copied onto a predetermined recording paper by a xerography method or the like, and is taken out from the discharge port (16). Next, when an image is displayed by electrostatic recording, an electrostatic latent image is recorded on the surface W of the recording medium (1) by the recording head (4), and the developing device (12) is transferred while the recording medium (1) is being transferred.
The black toner adheres to the charged portion to display a visible image. The cleaning blade (8) on the back side
Then, toner, ink written with a felt pen and the like are wiped off, and then the charge is removed by an AC static eliminator (7).

Here, to describe the recording state of the electrostatic latent image, the contact portion between the recording head (4) and the recording medium (1), the voltage pulse P ₁ for example plus a selected write voltage pulse is applied and styli electrode portion (5) a predetermined electrode in (5A), during a predetermined electrode in the control electrode section to which the voltage pulse P ₂ is applied minus (6) (6A),
An equivalent circuit as shown in FIG. 11 is formed via the dielectric layer (1c) and the conductive layer (1b) of the recording medium (1), and a discharge occurs between the stylus electrode (5A) and the dielectric layer (1c). , Gas ions remain on the dielectric layer (1c). Alternatively, use a stylus electrode (5
A) charges the dielectric layer (1c). (5B) is a stylus electrode of the same series, and (6B) is a control electrode adjacent to the selected control electrode. The recording head (4) is usually
As shown in FIG. 13, a plurality of stylus electrodes arranged in one direction and a plurality of (five in the example shown) stylus electrodes on both sides of the stylus electrode are provided so as to sandwich the stylus electrode. A so-called multi-head structure having a plurality of control electrodes [C ₁ , C ₂ ‥‥ C _n ] arranged as described above. The recording head (4) is driven by a recording matrix circuit as shown in FIG. That is, each control electrode (though one control electrode is omitted)
The five stylus electrodes facing C ₁ , C ₂ ‥‥ C ₇ are regarded as one electrode group, and two sets are arranged in such a manner that the electrodes corresponding to every other one of the plurality of electrode groups are in the same series. A
The terminals are divided into a series and a B series, and the stylus electrodes corresponding to each series are commonly connected to each other to derive terminals a _{1 to} a ₅ and terminals b _{1 to} b ₅ , and each terminal a _{1 to} a ₅ , b ₁ to independent of the write voltage is applied to b _5. On the other hand, independent of the selection voltage is applied to each control electrode C ₁ -C _7. Thus, for example, a stylus electrode side in the case of writing to _a point x in Figure 12 for this terminal b ₂ voltage pulse P ₁ plus is applied to the terminal b ₂ of B series is selected, the control electrode side control to electrode C ₄ is selected voltage pulse P ₂ minus is applied. In this case, x ₂ points of Figure 11 to be all stylus electrodes on the same series, which are connected to the terminal b _2, to the stylus electrodes ₃ points x voltage pulse P ₁ plus is applied in the stylus electrode side In other words, it is in a semi-selected state. Positive and negative voltage pulses P ₁ and P _2,
This does not discharge the semi-selected state, are adjusted to discharge only in the selected state, that is x ₁ point.

[Problems to be solved by the invention]

Incidentally, in the electrostatic recording medium (1) as shown in FIG. 10, the dielectric layer (1c) has a white color so that written characters and the like can be displayed well. If polyvinylidene fluoride contains titanium oxide as the dielectric layer (1c), the performance of the dielectric layer (1c) deteriorates. That is, titanium oxide has properties as an optical semiconductor, and when exposed to light depending on the use state of the electronic blackboard, the dielectric constant and volume resistivity of the dielectric layer (1c) decrease, and the recording head (4) causes the dielectric layer (1c) to decrease. In this case, the amount of charge accumulated in the recording medium (1) is reduced, and the writing state of the original on the recording medium (1) is deteriorated.

The conductive layer made of a deposited film or the like (1b), the relatively high state suitable surface resistance value in the writing of an electrostatic latent image (10 ⁴ to 10 ⁸
(Ω / □), it was difficult to make it uniform. For this reason, the amount of electric charge accumulated in the dielectric layer (1c) by the recording head (4) is not stable from this point, and the writing state of the original on the recording medium (1) is not uniform. Was.

Further, when the recording medium (1) is mounted in an endless state as shown in FIG. 8, there is a possibility that the deposited film may peel off from the base (1a) at a bent portion such as a contact portion with the drive roller (3). At the same time, the base (1a) made of vinyl chloride may be extended by the tension applied from the drive roller (3) or the like, and the durability of the recording medium was low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an electrostatic recording medium capable of performing favorable display by writing a document.

[Means for solving the problem]

The electrostatic recording medium of the present invention is an electrostatic recording medium comprising a sheet-like base, a conductive layer formed on the base, and a dielectric layer formed on the conductive layer, wherein the base or the conductive layer is It is characterized by being white, and the base is insulating.

Further, another aspect of the electrostatic recording medium according to the present invention uses the above-mentioned base made of polyethylene terephthalate.

According to another aspect of the present invention, in the electrostatic recording medium described above, the conductive layer includes a polymer containing a conductive substance.

Another aspect of the present invention is an electrostatic recording medium including a sheet-like base, a conductive layer formed on the base, and a dielectric layer formed on the conductive layer. An adhesive layer for adhering the dielectric layer, and the adhesive layer reduces the amount of transmitted ultraviolet light.

[Action]

According to the electrostatic recording medium of the present invention, the dielectric layer can be made transparent by making the base or the conductive layer white, and for example, by making this dielectric layer polyvinylidene fluoride, the dielectric layer having good characteristics can be obtained. It is possible to form a layer, and display by writing a document can be performed favorably.

〔Example〕

Hereinafter, an embodiment of the electrostatic recording medium of the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

The electrostatic recording medium of this example is used for an electronic blackboard with a display function as shown in FIG.
0) indicates the entire electrostatic recording medium, and the recording medium (2
In (0), the base (21) is made of polyethylene terephthalate (PET) having a thickness of 100 μm. And this base (21)
A conductive layer (23) made of a polymer such as polyurethane and having a thickness of 50μ is formed thereon via an adhesive layer (22) having a thickness of 10μ. The polymer forming the conductive layer (23) contains a conductive substance such as a metal oxide such as titanium oxide or indium oxide to have conductivity and to be white.

Then, a 25 μm thick dielectric layer (23) made of transparent polyvinylidene fluoride is formed on the conductive layer (22) via an adhesive layer (24) having a thickness of 10μ. In this case, the pressure-sensitive adhesive layer (24) contains an ultraviolet ray cut agent.
The pressure-sensitive adhesive is used because polyvinylidene fluoride is a substance that cannot be bonded with an adhesive. And
The surface of the dielectric layer (25) is used as a surface W for writing.

Then, the electrostatic recording medium (20) of this example is mounted in an endless form on an electronic blackboard as shown in FIG. At this time, the writing surface W is set to the front side. By doing so, an electrostatic latent image is formed on the recording medium (20) by the recording head (4). First, as shown in FIG. 2, the recording head (4) of the electronic blackboard is arranged such that the vicinity of the central stylus electrode portion (5) is formed on the electrostatic recording medium (20). A roller (19) made of a soft material such as a sponge is provided at a position facing the stylus electrode section (5) with the recording medium (20) interposed therebetween. W is the recording head (4)
Is in contact with

As shown in FIGS. 3 and 4, the recording head (4) has a flexible structure in which a plurality of conductive portions (5c) constituting electrodes are arranged in parallel on a thin plate (5a) of glass or the like. The substrate (5b) is covered in a U-shape and the stylus electrode (5)
Is configured. In this case, each conductive portion (5c) is connected to a control circuit (not shown) of the recording head (4). Then, the control electrode section (6) is arranged so as to sandwich the side face of the stylus electrode section (5). This control electrode part (6)
Is a stainless steel plate (6b) that is divided at predetermined intervals to form control electrodes on the upper surface of a base (6a) made of ABS resin
Is attached, and the gap between the stainless steel plates (6b) is filled with silicon (6c). A conducting wire (6d) is led out from each stainless steel plate (6b) and connected to a control circuit of the recording head (4).

With this configuration, the conductive portion (5c) exposed above the stylus electrode portion (5) becomes a stylus electrode, and the stainless steel plates (6b) on both sides thereof become control electrodes.

The conductive layer (5c), which is a stylus electrode of the recording head (4), and the stainless steel plate (6b), which is a control electrode near the conductive layer, come into contact with the writing surface W of the electrostatic recording medium (20). Electric charges corresponding to the potential difference between the conductive portion (5c) and the stainless steel plate (6b) set by the control circuit accumulate in the dielectric layer (25) of the electrostatic recording medium (20), and the electric charge is reduced by the amount of electric charge. An electrostatic latent image is formed.

Then, the portion of the recording medium (20) where the electrostatic latent image is formed is sent to the developing device (12), so that a toner of a predetermined color (other than white) corresponding to the charge amount is formed on the writing surface W. The visible image corresponding to the original is written and displayed on the white recording medium (20) with the toner.

According to the electrostatic recording medium (20) of the present example written in this way, good display is performed. That is, the conductive layer (23) made of a polymer contains titanium oxide or indium oxide to make the recording medium (20) white, so that the dielectric layer (25) can be made transparent. Therefore, the dielectric constant (25) of the dielectric layer (25) does not change due to light or the like.
The writing state of the original is favorably performed. The conductive layer (2
In 3), since a polymer such as polyurethane contains titanium oxide or indium oxide, it is easy to make the surface resistance uniform at a relatively high value of, for example, 10 ⁴ to 10 ⁸ Ω □. The writing state is uniform and good. Further, since the conductive layer (23) is fixed to the base (21) with an adhesive, there is no danger of peeling off from the base like a vapor-deposited film, and the base (21) is made of polyethylene terephthalate, which has a small expansion. Therefore, the durability of the electrostatic recording medium (20) is high. Further, since the adhesive for bonding the transparent dielectric layer (25) and the white conductive layer (23) contains an ultraviolet cut agent, the color (white) of the conductive layer (23) is used.
Is prevented from changing over time due to ultraviolet light.

As shown in FIG. 5, a hard coat layer (26) is applied to the surface of the dielectric layer (25) as an electrostatic recording medium (20 '), and the surface of the hard coat layer (26) is written. The surface W may be used. As the hard coat, for example, one sold under the trade name of tough coat is used. By doing so, it is possible to prevent the writing surface W from being damaged and to easily erase characters and the like written on the writing surface W.

Further, as the electrostatic recording medium, the conductive layer may be transparent and the base may be white. That is, as shown in FIG. 6, a base (31) is made of white polyethylene terephthalate as an electrostatic recording medium (30), and an ITO film (indium synoxide film) as a transparent electrode is formed on the base (31).
Is formed as a conductive layer (32) by vapor deposition, and a dielectric layer (34) made of transparent polyvinylidene fluoride is formed on the conductive layer (32) via an adhesive layer (33). ) May be used as the writing surface W. Alternatively, an ITO film as a conductive layer (32) may be formed on the lower surface of the dielectric layer (34).

By doing so, the dielectric layer (34) is formed in the same manner as in the example of FIG.
In addition, the characteristics of the conductive layer (32) are improved, so that writing of a document can be performed satisfactorily.

Further, as shown in FIG. 7, a base (41) made of polyethylene terephthalate is used as the electrostatic recording medium (40).
A conductive paint (42) having a white color and conductivity may be applied thereon to form a conductive layer, and a dielectric layer (43) made of transparent polyvinylidene fluoride may be formed on the conductive paint (42). .

In the case of FIG. 7 as well, the characteristics of the dielectric layer (43) and the paint (42) as the conductive layer are good, as in the case of FIG.

In addition, when the electrostatic recording medium has the above-described configuration, and the fixing property of the toner on the medium is improved,
For example, a double cleaning blade may be provided so that erasing is completely performed. Further, a cleaning brush may be used together with the cleaning blade to erase traces of fingerprints on the medium. Further, such an erasing means can be arranged to prevent erasing from being performed away from the electrostatic recording medium as necessary.

Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

〔The invention's effect〕

According to the electrostatic recording medium of the present invention, since the conductive layer or the base is made white, the dielectric layer can be made transparent, so that the characteristics of the dielectric layer become good, and the display by writing of the original becomes good. There are benefits that can be made.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the electrostatic recording medium of the present invention, FIG. 2 is a structural view showing a recording state, FIG. 3 is a perspective view showing an example of a recording head, and FIG. FIG. 5, FIG. 6, FIG. 7, and FIG. 7 are cross-sectional views showing another embodiment of the electrostatic recording medium of the present invention, and FIG. 8 and FIG. FIG. 10 is a perspective view showing an example of a blackboard, FIG. 10 is a sectional view showing an example of a conventional electrostatic recording medium, FIG. 11 is a diagram showing a recording principle, and FIG. 12 is a recording matrix circuit for driving a recording head. FIG. 13 is a front view showing an example of a recording head. (20), (30) and (40) are electrostatic recording media, (21),
(31) and (41) are bases, (23) and (32) are conductive layers, (25), (34) and (43) are dielectric layers, and (42) is a conductive paint.

Claims (4)

(57) [Claims] 1. An electrostatic recording medium comprising a sheet-like base, a conductive layer formed on the base, and a dielectric layer formed on the conductive layer, wherein the base or the conductive layer is white. An electrostatic recording medium, characterized in that the base is insulative. 2. The electrostatic recording medium according to claim 1, wherein polyethylene terephthalate is used for said base. 3. The electrostatic recording medium according to claim 1, wherein said conductive layer comprises a polymer containing a conductive substance. 4. An electrostatic recording medium comprising a sheet-like base, a conductive layer formed on the base, and a dielectric layer formed on the conductive layer, for adhering the conductive layer and the dielectric layer. An electrostatic recording medium comprising: an adhesive layer; and an adhesive layer that reduces the amount of transmitted ultraviolet light.