JP3208592B2 - Display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic blackboard and the like for displaying a latent image formed on an image carrier such as a dielectric belt by a latent image forming means such as an electrostatic recording head as a toner image by a developing means for display. The present invention relates to a display device.

[0002]

2. Description of the Related Art Conventionally, a blackboard sheet is composed of an image carrier such as a dielectric belt, and a latent image is formed on the blackboard sheet based on document information from a reading device or the like. 2. Description of the Related Art An electronic blackboard device with a display function of developing with a developing device used for display is known (for example, see Japanese Unexamined Patent Application Publication No.
129375). A similar display device is also known as a display device connected to a computer or the like. In addition, it is possible to write on the image carrier in a display state with a felt pen or the like facing the opening of the device housing constituting the display unit, and to erase the toner image in the display state by erasing a blackboard or the like. For this reason, the toner image before being displayed by the flash fixing device does not easily fall off even if a hand or the like comes into contact at the time of rewriting, and is in a semi-fixed state in which the above-mentioned erasing is possible. Some are known.

[0003]

However, these display devices employ a developing device using a dry developer as a means for developing a latent image on an image carrier.
During development of a latent image or cleaning of the surface of an image carrier, powder toner may be scattered inside and outside the apparatus. In the case where the display unit is constituted by the opening of the device housing, in order to prevent powder toner from scattering from the opening to the outside of the device,
It is also known to close the opening with a transparent member, but in this case too, powder toner adheres to the surface of the transparent member on the inner side of the device, and the display becomes unclear. In the case where the toner image is made to be in a semi-fixed state on the image carrier, since the toner image is a toner image composed of a powder toner, it is compared with a toner image composed of a liquid toner obtained by developing with a liquid developer. Large fixing energy is required.

In order to solve the above-mentioned problems, the present inventors have employed a developing device using a liquid developer as a developing means for developing a latent image on an image carrier. Could be solved. However, he also discovered the following new defect. That is, when a conventionally known liquid developer, for example, as disclosed in JP-A-62-18572, is used, the solvent in the toner image formed on the image carrier is evaporated. It has been found that the toner constituting the toner image strongly adheres to the image carrier, which makes it difficult to remove the toner image by the cleaning device. This is because the binding force of the binder resin dispersed in the toner and sticking or solidifying when the solvent evaporates is too strong. That is,
In conventional toner, a binder resin that exhibits a strong binding force and is easily fixed and fixed on the transfer paper fibers or transfer material is dispersed so that the toner image can be permanently fixed to the transfer material. It is. In particular, when a thermosetting substance is mixed in the toner, the toner is strongly fixed on the image carrier by heat fixing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to reduce toner scattering inside and outside the apparatus as compared with the prior art , and to use a cleaning device to clean a toner image on an image carrier. Is to provide a display device that can easily remove the display. Also, the second object is to provide a display device can be made smaller than the d <br/> energy for pre-drying the toner image on the image carrier to be in a display state in the prior art.

[0006]

In order to achieve the first object, the present invention is directed to an image bearing member, a latent image forming means for forming a latent image on the image bearing member, and Developing means for attaching toner to the latent image to form a toner image on the image carrier, and cleaning means for removing the toner image from the image carrier
And a grayed section while subjected to display the toner image, said image
In a display device that repeatedly uses a carrier for display, a liquid developing device that supplies a liquid developer to the surface of the image carrier and adheres toner to the latent image is used as the developing unit.
As a binder resin, one of the main components of toner in liquid developer
And the expression (Where R represents H or CH 3, n is 1, 2,
Polymer having a repeating unit represented by 3, 4, or 5)
Or a copolymer . Here, as the image carrier and the latent image forming means, those used in various conventionally known recording methods can be used. For example, a photoconductive photoreceptor can be used as the image carrier, and an optical writing device can be used as the latent image forming means. An electrostatic recording medium can be used as the image carrier, and an electrostatic recording head can be used as the latent image forming means. Further, an electrostatic recording medium in which potential is attenuated by heating after charging as an image carrier, and a thermal writing device as a latent image forming means can be used. Further, as the liquid developer, a two-component liquid developer composed of a liquid carrier and a toner may be used, or a one-component liquid developer composed of only a toner may be used.

[0007]

[0008] To further achieve the above second object, the invention of claim 2, in the display device according to claim 1, a display unit constituted by the opening of the apparatus housing, the surface of the image carrier composed of a material having releasability and over on top Kizo carrier
A drying means for drying the toner image is provided.

According to a third aspect of the present invention, in the display device of the second aspect, a backup member is provided so as to face the surface of the image carrier facing the opening opposite to the surface opposite to the opening. It is characterized by the following.

[0010]

According to the first aspect of the present invention, a latent image is formed on an image carrier by a latent image forming means, and a liquid developer is supplied to a surface of the image carrier on which the latent image is formed by a liquid developing device. Thus, the latent image is converted into a toner image, and the toner image on the image carrier formed by the liquid developing device is displayed. Also display
Cleaning the toner image on the image carrier
Means, thereby repeatedly displaying the image carrier on the display.
And use it. And, as a binder resin, one of the main components,
Use a toner that uses the specified polymer or copolymer.
To use. This toner has a stronger binding force than a conventionally known toner.
Is weak. In addition, this toner evaporates the solvent on the image carrier and
The same as when using a conventional felt-tip pen, etc.
Each time it becomes a powder with a large particle size.

[0011]

[0012] In the invention of claim 2, prior to subjecting to the display on the display unit constituted by the opening of the apparatus housing, the toner image on the I Riue Kizo bearing member drying means to dry . Here, the toner image is because those formed by using a liquid developer can be the by Do et <br/> energy smaller than the conventional powder toner dry. In addition, since the surface of the image carrier is made of a material having releasability, the toner image in a dry state on the display section can be relatively easily erased by a rubbing member such as a blackboard eraser. Furthermore, when a toner using a predetermined polymer or a copolymer as a binder resin, which is one of the main components, is used, erasing by a rubbing member such as a blackboard eraser becomes easier.

According to the third aspect of the invention, when writing is performed directly on the image carrier through the opening with a felt pen or the like, the back surface of the image carrier is supported by the backup member.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electronic blackboard device having a display function as a display device will be described below. FIG. 1A is a schematic configuration diagram of an electronic blackboard device according to the present embodiment. An endless belt-shaped blackboard sheet 1 as an image carrier is stretched over a pair of rollers 2 and 3. The color of the surface of the blackboard sheet 1 is not limited to black, but may be white or another color. The blackboard sheet 1 of this example has a photoconductive layer 12 formed on a conductive base layer 11 and a surface layer 13 made of a release material, as shown in FIG. 1B. For example, the conductive base layer 11 can be composed of an aluminum-evaporated polyester film. The photoconductive layer 12 can be constituted by a layer having a thickness of about 50 μm made of a silicone-modified acrylic resin in which photoconductive ZnO spectrally sensitized with a merocyanine dye is dispersed. Further, the surface layer 13 can be composed of a release silicone resin layer applied to a thickness of about 10 μm by a spray method. A drive source (not shown) is connected to at least one of the rollers 2 and 3 so that the blackboard sheet 1 can be transferred endlessly. The arrow A in the figure indicates the direction of movement of the blackboard sheet 1 during the formation of the toner image in the display operation. May be transported.

A latent image forming unit 4 serving as a latent image forming means is disposed opposite to the surface of the blackboard sheet 1. The latent image forming unit 4 in this example includes a corona charger 4
1, an LD light source 42a, a collimator lens 42b, a polygon mirror 42c, an f-θ lens 42d, and a first mirror 4
And an optical writing unit 42 made of 2e or the like. The light writing position by the light writing unit 42 is set downstream of the corona charger 41 in the transfer direction A during the formation of the toner image. In addition,
The drive of the optical writing unit 42 is controlled by a controller (not shown). As the information to be input to the controller, a document reading device may be attached to the apparatus and information from now on may be used, or information from another computer may be used.

A cleaning device 5 is provided so as to face the surface of the blackboard sheet 1 downstream of the latent image forming unit 4 in the transfer direction A. The cleaning device 5 of this example is a cleaning roller 52 (for example, a foam roller) that is driven to rotate clockwise with an arrow while the cleaning liquid is supplied from a supply nozzle 51.
And a cleaning blade 53. As the cleaning liquid, a liquid developer in a developer tank described later can be used. The cleaning roller 52 and the cleaning blade 53 are supported by a support mechanism (not shown) so as to be able to selectively take an operating position in contact with the surface of the blackboard sheet 1 and a retracted position separated from the surface. The cleaning device 5
The LED array 54 as a charge removing means is arranged so as to face the surface of the blackboard sheet 1 on the upstream side in the transfer direction A.
Are also provided.

A liquid developing device 6 as a developing means is disposed facing the surface of the blackboard sheet 1 downstream of the cleaning device 5 in the transfer direction A. The liquid developing device 6 of this example includes a developer tank 61 containing a liquid developer, a toner supply can 62 containing toner to be supplied into the tank, and a supply pipe 63a for pumping up the liquid developer in the tank 61. , A first developing roller 64 and a second developing roller 65 for supplying the liquid developer from the supply pipe 63a to the surface of the blackboard sheet 1, and a squeeze roller 66.
The first and second developing rollers 64 and 65 are made of Al, SU
The gap between the surface of the blackboard sheet 1 and the surface of the blackboard sheet 1 is maintained at about 100 μm by contacting spacer rollers provided at both ends of a shaft (not shown) with the end surface of the roller 3 with a pressing spring or the like. . Then, it is rotationally driven clockwise by an arrow by a drive mechanism (not shown). In this example, in order to form a developing electric field between the blackboard sheet 1 and each of the developing rollers 64 and 65, a voltage is applied to each of the developing rollers 64 and 65 from a power source (not shown). The developing roller 64, 65 and the blackboard sheet 1 are insulated from each other by insulating the end surface of the roller 3 with which the roller surface contacts. The squeeze roller 66 has a gap between the squeeze roller 66 and the surface of the blackboard sheet 1 maintained at about 50 μm by the same support mechanism as the developing rollers 64 and 65. The sheet 1 is rotationally driven at a high speed in the direction in which the surface moves in the same direction as the surface movement direction. The liquid developer used in the liquid developing device 6 will be described later in detail.

A blower 7 as a drying means is disposed opposite the surface of the blackboard sheet 1 downstream of the liquid developing device 6 in the transfer direction A. This blower 7 prevents the toner image from soiling hands and clothes when the surface of the blackboard sheet 1 is touched with a felt pen or the like while the toner image is formed and displayed on the blackboard sheet 1. In order to do so, the toner image is dried to a degree that does not stain the hands and clothes before being displayed.

The whole appearance of the electronic blackboard device is covered with a casing 8, a window 8a is formed as an opening on the entire surface of the casing 8, and the blackboard sheet 1 is formed through the window 8a.
It is possible to write on the surface with a felt-tip pen, or to write with a felt-tip pen or the like in a display state in which the surface area of the blackboard sheet 1 on which the toner image is formed in the window 8a is opposed to each other. ing. Also, this window 8a
A back-up member 8 for facilitating writing and rewriting with a felt pen or the like is provided on the back side of the blackboard sheet 1 facing the
1 is provided.

In the above configuration, when this electronic blackboard device is used as a normal blackboard, the user writes in the surface area of the blackboard sheet 1 facing the window 8a with a felt pen or the like.
Erase by blackboard eraser as appropriate. At this time, the blackboard sheet 1 can be run by an operator's instruction to change the area facing the window 8a.

Then, a toner image is formed on the blackboard sheet 1 on the basis of information from a document reading device or another computer attached to the main body, and a region where the toner image is formed is opposed to the window 8a. Actions can be taken. Hereinafter, this display operation will be described. When a display operation is instructed, first, the cleaning device 5 is moved to the operation position, and the blackboard sheet 1 is caused to travel in the direction of arrow A while performing the cleaning operation. Clean the large blackboard sheet 1 area. At this time, the charge may be removed by driving the LED array 54 as needed. Then, the cleaned blackboard sheet 1 area is uniformly charged by the corona charger 41, and the portion where the toner corresponding to the background of the image is not adhered to the charged area by the optical writing unit 42 driven and controlled by the controller. (Hereinafter, a non-image portion. Further, a portion of the image to which toner is to be attached is referred to as an image portion.) Light is irradiated to form a latent image. Then, after the cleaning is completed, the cleaning device 5 is moved to the evacuation position, and passes through a portion facing the cleaning device 5.
While passing through a portion facing the liquid developing device 6 in the operating state,
The latent image is developed to form a toner image. This development is a regular development in which toner charged to the same polarity as the charging polarity by the corona charger 41 is attached to the high potential portion of the blackboard sheet 1. Specifically, the first and second developing rollers 64 and 65 to which a bias for preventing background contamination has been applied as necessary.
The liquid developer held on the peripheral surfaces of the developing rollers 64 and 65 is supplied to the surface of the blackboard sheet 1 while passing through the gap between the developing roller 64 and 65, and the charged toner in the liquid developer adheres to the high potential portion of the latent image. Excess liquid developer is removed by the squeeze roller 66.
Then, the solvent in the toner image on the blackboard sheet 1 is evaporated by the blower 7 and sent to the portion facing the window 8a. When the entire toner image faces the window 8a, the blackboard sheet 1
Is stopped, and thereby the display state is set. In this display state, the surface of the blackboard sheet 1 can be directly retouched with a felt pen or the like via the window 8a, and at this time, the back side of the blackboard sheet 1 is backed up by the backup member 81.

As described above, according to the present embodiment, the toner image to be displayed is formed by using the liquid developer of the liquid developing device 6, so that the toner image to be displayed is formed by using the powder toner of the dry developing device as in the prior art. In comparison, it is possible to reduce toner scattering inside the apparatus during development and toner scattering outside the apparatus from the window 8a. In addition, when directly writing on the blackboard sheet 1 in the display state through the window 8a, the energy consumed by the blower 7 for preventing the toner image from soiling the hands and clothes is consumed by the liquid developing device. Since the formed toner image can be fixed by evaporating the solvent component, compared to the energy consumed by the fixing device for semi-fixing the toner powder prior to display when using a conventional dry developing device. And small. Further, since the backup member 81 is disposed on the back surface of the blackboard sheet 1 facing the window portion 8a, it is easy to write on the blackboard sheet 1 with a felt pen or the like.

Next, the liquid developer used in the liquid developing device 6 will be described. As the liquid developer of this embodiment, a two-component liquid developer including a liquid carrier and a toner is used. Examples of the liquid carrier include isododecane, n-hexane, and commercially available Shersol-71.
(Manufactured by Shell Sekiyu KK), Isopar G, H, E, L, K,
M, V (manufactured by Exxon) or the like can be used. Further, more as environmental health preferred odorless, dimethylpolysiloxane (e.g., manufactured by Shin-Etsu Chemical, KF96L
-0.65, KF96L-1.0, KF96L-1.
5), phenylmethyl polysiloxane (e.g., manufactured by Shin-Etsu Chemical, KF58), cyclic dimethylpolysiloxane (e.g., manufactured by Shin-Etsu Chemical, can also be used KF994).

The toner has a colorant and a binder resin as main components and, if necessary, a dispersion resin and a charge controlling agent. Examples of the coloring agent include inorganic pigments such as furnace black, acetylene black, and channel black as carbon black, and PRINTEX G, PRINTEX V, special black 15, special black 4, and special black 4-B (Degussa Co., Ltd.) as commercial products. Manufactured), Mitsubishi # 44, # 30, MA-11, MA-10
0 (Mitsubishi Carbon), Raven 30, Raven 4
0, Conductex SC (manufactured by Columbia Carbon), Legal 400, 600, 800, Black Pearl L (manufactured by Cabot) and the like. Further, inorganic white pigments such as zinc oxide, titanium oxide and silicon oxide can also be exemplified. Organic pigments, for example, phthalocyanine blue, phthalocyanine green, rhodamine lake, malachite green lake, methyl violet lake, peacock blue lake, nattole green B, permanent red 4R, Hansa yellow, benzidine yellow, thioindigolet, etc. . Further, an organic pigment alone, an inorganic pigment alone, or a mixed system of an organic pigment and an inorganic pigment may be used.

The binder resin is represented by the following formula: (Where R represents H or CH 3, n is 1, 2,
3, 4, 5, 6, 7, or 8, preferably 1, 2, 3, or 4), is used a polymer or a copolymer (a resin containing an acrylic ester) having a repeating unit. For example, polymethyl methacrylate, polyeryl methacrylate, polybutyl methacrylate, polyisobutyl methacrylate, poly 2-ethylhexyl methacrylate, polymethyl acrylate, polybutyl acrylate, poly 2-ethyl hexyl acrylate and the like can be mentioned.

The liquid developer is adjusted, for example, by mixing 0.3 to 3 parts by weight of a binder resin with 1 part by weight of a coloring agent, and mixing the mixture with 10 to 20 parts by weight of the liquid carrier. Attritor, ball mill, Keddy mill,
Disperse sufficiently with a dispersing machine such as a pearl mill to obtain a concentrated toner,
If necessary, this is diluted 3 to 10 times with the liquid carrier. In addition, if necessary, a dispersion control (hereinafter, margin) resin and a polarity controlling agent such as metal soap, lecithin, linseed oil, and higher fatty acid can be added to the mixture of the colorant and the binder resin.

When the above liquid developer is used, since the above-mentioned predetermined binder resin is used as the binder resin which is one of the main components of the toner, the binding force of the toner is lower than that of a conventionally known toner. Weak. Therefore, even when the solvent evaporates from the toner image on the blackboard sheet 1 made of the toner, the toner does not adhere to the surface of the blackboard sheet 1 as strongly as in the case of using a conventionally known toner. Therefore, the erasing of the toner image by erasing the blackboard or the like in the toner image display state, and the removal of the toner image from the blackboard sheet 1 by the cleaning device 5 become easy. Further, when the solvent evaporates on the image carrier, the toner becomes powdery with a particle size as large as that when writing with a conventional felt pen or the like. Even if toner adheres to hands or clothes when writing with a felt pen or the like, it can be easily washed off.

Hereinafter, specific examples of the toner using the binder resin will be described. [Specific Example 1] 100 parts by weight of carbon black (Mitsubishi # 44 manufactured by Mitsubishi Carbon) and polymethyl methacrylate 8
A mixture of 0 parts by weight, 300 parts by weight of Isopar H (manufactured by Exxon Corporation) and 0.1 part by weight of lecithin was dispersed for 10 hours by an attritor to prepare a toner having an average particle diameter of 0.8 μm. [Specific Example 2] 100 parts by weight of carbon black (Mitsubishi # 44 manufactured by Mitsubishi Carbon Co., Ltd.) and polymethyl methacrylate 8
0 parts by weight, dimethylpolysiloxane (manufactured by Shin-Etsu Chemical Co. of KF
96L-1.0) A mixture of 300 parts by weight of lecithin and 0.1 part by weight of lecithin was dispersed in a ball mill for 24 hours to prepare a toner having an average particle diameter of 1.3 μm. [Specific Example 3] Polyethyl methacrylate / 2-ethylhexyl methacrylate copolymer (molar ratio 50/50) as a binder resin
A toner having an average particle diameter of 1.4 μm was prepared by the same formulation and dispersion method as in Example 2 except for using. [Specific Example 4] A toner having an average particle diameter of 1.3 µm was prepared by the same formulation and dispersion method as in Specific Example 2 except that polybutyl methacrylate was used as the binder resin. [Specific Example 5] A toner having an average particle diameter of 1.0 µm was prepared by the same formulation and dispersion method as in Specific Example 2 except that polyisobutyl methacrylate was used as the binder resin. [Specific Example 6] A toner having an average particle diameter of 0.85 µm was prepared by the same formulation and dispersion method as in Specific Example 2 except that poly-2ethylhexyl methacrylate was used as the binder resin. Comparative Example A toner having an average particle diameter of 1.1 μm was prepared by the same formulation and dispersion method as in Example 2 except that polylauryl methacrylate was used as the binder resin.

A toner image is formed with a liquid developer using the toner according to the above specific examples and comparative examples, and is displayed.
Eight hours later, the toner image was erased by a blackboard eraser, PILOT new whiteboard Eraser.
(Made by Pilot). Ease of erasure at this time was determined. The following table shows the result of this determination together with the image density (reflection density by Macbeth densitometer) of the toner image on the blackboard sheet 1 before erasure. In addition to the above determination, a state in which the toner adhered to the cloth was observed 10 minutes after wiping the A4 size black solid toner image formed on the blackboard sheet 1 with the cloth. In Nos. 1 to 4, the toner powder was easily removed. Further, in the specific examples 5 and 6, although the toner powder could not be completely removed easily and some dirt was conspicuous, the toner could be removed to the extent that there was no problem in washing. On the other hand, in the comparative example, the stain was still adhered even after washing.

In the electronic blackboard apparatus shown in FIG. 1, the blackboard sheet 1 in the displayed state can be directly added using a felt pen or the like via the window 8a. As shown in FIG. 2A, a transparent cover 82 made of, for example, a transparent acrylic resin is provided so as to cover the window 8a, and the transparent cover 82 is retouched with a felt pen or the like. The image may be superimposed and viewed. In this case, since the retouching is not performed directly on the blackboard sheet 1, the blower 7 (FIG. 1)
(A)) can be omitted.

In the electronic blackboard apparatus shown in FIG. 1, the latent image forming unit 4 uses the optical writing unit 42 composed of the LD light source 42a and the like.
As shown in (b), for example, a 2 mm pitch LED array 43 may be used. In this case, the LED array 43 is also used for static elimination of the blackboard sheet 1 before cleaning, whereby the LED array 54 dedicated to static elimination in FIG. 1 can be omitted. Thus, the LED array 43 for forming a latent image
Is also used for the pre-cleaning charge removal of the blackboard sheet 1, the entire surface is turned on during the pre-cleaning charge removal operation, and the entire width of the image forming area of the blackboard sheet 1 is removed.
Of course, in this case as well, as in the apparatus of FIG.
A transparent cover 82 made of, for example, a transparent acrylic resin is provided so as to cover a, and the transparent cover 82 is retouched with a felt pen or the like, and the retouched line drawing and the toner image on the blackboard sheet 1 are superimposed and visually observed. Alternatively, the blower 7 may be omitted.

In the electronic blackboard device shown in FIG. 1, the optical writing unit 4 is driven to irradiate the non-image portion with light to form a latent image, and the latent image is normally developed. Instead, the optical writing unit 4 is driven to irradiate the image portion with light so as to form a latent image, and the toner of the toner is adhered to the low potential portion irradiated with the light of the latent image. It is also possible to apply a developing bias having the same polarity as the charging polarity to each of the developing rollers 64 and 65 to perform reversal development. Of course, also in this case, similarly to the apparatus of FIG. 2A, a transparent cover 82 made of, for example, a transparent acrylic resin is provided so as to cover the window 8a, and the transparent cover 82 is rewritten with a felt pen or the like. The added line drawing and the toner image on the blackboard sheet 1 may be superimposed and viewed, and the blower 7 may be omitted.

In the electronic blackboard apparatus shown in FIG. 1, the latent image is formed by an electrophotographic method. Alternatively, the latent image may be formed by an electrostatic recording method. In this case, a blackboard sheet 1 having a dielectric layer is used. For example, as shown in FIG. 3B, a material in which a dielectric layer 14 is formed on the conductive base layer 11 and the surface layer 13 is made of a release material can be used. For example, the conductive base layer 11 can be composed of an aluminum-evaporated polyester film. The dielectric layer 14 can be constituted by a layer having a thickness of about 30 μm made of a silicone-modified acrylic resin in which white TiO ₂ is dispersed. Further, the surface layer 13 can be composed of a release silicone resin layer applied to a thickness of about 10 μm by a spray method.
Then, for example, as shown in FIG.
The direct-discharge type recording head 44 of the same surface control type in which the recording electrode 44a and the control electrode 44b are disposed on the same surface side of the blackboard sheet 1 is disposed so as to be in contact with the surface of the blackboard sheet 1. In this case, the image portion is directly charged to a high potential by the discharge recording head 44, and is normally developed with a toner having a polarity opposite to that of the potential portion. Of course, also in this case, as shown in the drawing, a transparent cover 82 made of, for example, a transparent acrylic resin is provided so as to cover the window 8a, and the transparent cover 82 is retouched with a felt pen or the like, and the retouched line drawing and the blackboard sheet are added. The toner image on the first image may be superimposed and visually checked, and the blower 7 may be omitted. In the example shown in FIG. 3A, an AC corona discharger 55 is used as a means for removing electricity from the blackboard sheet 1 before cleaning.

When the blackboard sheet 1 having the dielectric layer 14 is used as shown in FIG. 3A, the latent image forming unit 4 is connected to the corona charger 41 and the direct discharge type recording head as shown in FIG. The direct discharge recording head 44 is driven by applying a charge having a polarity opposite to the charge polarity to the blackboard sheet 1 uniformly charged by the corona charger 41 so that the image portion becomes a low potential portion. You may do it. In this case, reverse development is performed using a bias having the same polarity as the toner as a developing bias in order to attach the toner to the low potential portion. Conversely, the direct discharge recording head 44 is driven by applying a charge of the opposite polarity to the charged polarity on the blackboard sheet 1 uniformly charged by the corona charger 41 so that the non-image portion becomes a low potential portion. Alternatively, regular development may be performed in order to attach toner to the high potential portion.

Further, when the blackboard sheet 1 having the dielectric layer 14 is used as shown in FIG. 3A, the latent image forming unit 4 is provided with an ion current controlling aperture electrode 45a as shown in FIG. 4B. It is also possible to use an indirect discharge type recording head 45 composed of a corona discharger 45b. In this case, similarly to the apparatus shown in FIG. 3A, the image portion is charged to a high potential by the indirect discharge recording head 45, and is normally developed with a toner having a polarity opposite to that of the potential portion. Also in this case, a corona charger 41 is added to the latent image forming unit 4 as in FIG. 4A, and the indirect discharge recording head 45 is moved to the corona charger 4.
The blackboard sheet 1 uniformly charged in step 1 may be driven so that a charge having a polarity opposite to the charge polarity is given to partially remove the charge to form a latent image.

In the electronic blackboard apparatus shown in FIG. 1, the latent image is formed by an electrophotographic method. Alternatively, the latent image may be formed by a thermal writing method. In this case, a blackboard sheet 1 having a dielectric layer whose charging potential is reduced (causes potential attenuation) by heating is used. For example, as shown in FIG. 5B, a material in which the dielectric layer 18 is formed on the conductive base layer 11 and the surface layer 13 is made of a release material can be used. For example, the conductive base layer 1
1 can be composed of aluminum-deposited polyimide. The dielectric layer 15 can be constituted by a layer having a thickness of about 30 μm made of a silicone-modified acrylic resin in which white TiO ₂ is dispersed. Further, the surface layer 13 can be composed of a release silicone resin layer applied to a thickness of about 10 μm by a spray method.
Then, for example, as shown in FIG.
Is composed of a corona charger 41 and a heating writing head 46. In this case, the blackboard sheet 1 uniformly charged by the corona charger 41 is heated to drive the thermal writing head 46 so that the image portion becomes a low-potential portion, and toner is attached to the low-potential portion. Therefore, it is desirable to perform reversal development using a bias having the same polarity as the toner as the developing bias. Of course, also in this case, as shown in the figure, a transparent cover 82 made of, for example, a transparent acrylic resin is provided so as to cover the window 8a, and the transparent cover 82 is retouched with a felt pen or the like, and the retouched line drawing and the blackboard sheet are added. The toner image on the first image may be superimposed and visually checked, and the blower 7 may be omitted. In the illustrated example, an AC corona discharger 55 is used as a means for removing electricity from the blackboard sheet 1 before cleaning.

[0037]

According to the display device of the present invention, the latent image formed on the image carrier by the latent image forming means is
Since a liquid developer supplies a liquid developer to the surface of the image carrier to form a toner image and provides the toner image for display, toner scattering inside and outside the apparatus is reduced as compared with a conventional dry developing apparatus. There is an excellent effect that you can. Further, after being provided for display, the image on the image carrier
The toner image is removed by cleaning means, and the image carrier is displayed.
When used repeatedly, binding is one of the main components
Use specified polymer or copolymer as resin
As a result, the toner having a weaker binding force than the conventionally known toner
Cleaning, the cleaning device is used to
Has an excellent effect that the toner image can be easily removed.
In addition, since the toner has weaker binding power than
The toner image provided to the printer by a rubbing member such as a blackboard eraser
It can be erased relatively easily. Also, this toner
Is a conventional felt when the solvent evaporates on the image carrier.
The particle size is as large as that of a pen
Therefore, if it gets on your hands or clothes, remove it easily.
Can be.

[0038]

Further, according to the display device of the second aspect of the present invention, since the toner image is formed by using the liquid developer, the toner image is provided for display on the display portion formed by the opening of the device housing. to prior, drying means over on I Riue Kizo carrier to
Per the serial toner image to a dry state, the at Do energy smaller than the conventional powder toner dry. Also,
Since the surface of the image carrier is made of a material having releasability, the toner image in a dry state in the display unit,
It can be erased relatively easily by a rubbing member such as a blackboard eraser.
Furthermore, when a toner using a predetermined polymer or a copolymer as a binder resin, which is one of the main components, is used, erasing by a rubbing member such as a blackboard eraser becomes easier.

Further, according to the display device of the third aspect of the present invention, when writing is performed directly on the image carrier through the opening with a felt pen or the like, the back side of the image carrier by the backup member. Is supported, so that it is easy to directly write on the image carrier.

[Brief description of the drawings]

FIG. 1A is a side view illustrating a schematic configuration of an electronic blackboard device according to an embodiment, and FIG. 1B is a cross-sectional view of a blackboard sheet of the electronic blackboard device.

FIGS. 2A and 2B are side views each showing a schematic configuration of an electronic blackboard device according to another embodiment.

FIG. 3A is a side view showing a schematic configuration of an electronic blackboard device according to still another embodiment, and FIG. 3B is a cross-sectional view of a blackboard sheet of the electronic blackboard device.

FIGS. 4A and 4B are side views each showing a schematic configuration of an electronic blackboard device according to still another embodiment.

FIG. 5A is a side view showing a schematic configuration of an electronic blackboard device according to still another embodiment, and FIG. 5B is a cross-sectional view of a blackboard sheet of the electronic blackboard device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 blackboard sheet, 11 conductive base layer 12 photoconductive layer, 13 surface layer 14 dielectric layer 15 dielectric layer having potential decay characteristic by heating 4 latent image forming unit, 41 corona charger 42 optical writing unit, 43 L
ED array 44 direct discharge type recording head, 45 indirect discharge type recording head 5 cleaning device, 6 liquid developing device 7 blower, 8 housing 8a window, 81 backup member

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Manabu Mochizuki 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (56) References JP-A-64-966 (JP, A) JP-A Sho 62-18572 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/22 G03G 9/13 G03G 15/10 H04N 1/29

Claims (3)

(57) [Claims] An image carrier, a latent image forming means for forming a latent image on the image carrier, and a developing means for adhering toner to the latent image to form a toner image on the image carrier. , The toner image
Cleaning means for removing from the image carrier ,
While the toner image is being displayed, the image carrier is repeatedly displayed.
In a display device that is used repeatedly, a liquid developing device that supplies a liquid developer to the surface of the image carrier and adheres toner to the latent image is used as the developing unit, and a main component of the toner of the liquid developer is used . With one binder resin
Then the formula (Where R represents H or CH 3, n is 1, 2,
Polymer having a repeating unit represented by 3, 4, or 5)
Or a display device using a copolymer . 2. The display device according to claim 1, wherein the display unit is constituted by an opening of the device housing.
The surface of the image carrier is made of a material having releasability, and
The toner image on the image carrier prior to providing for display
A drying means for drying the product is provided.
1 display device. 3. The image carrier portion facing the opening.
A backup unit facing the surface opposite to the opening.
The display device according to claim 2, wherein a material is provided.