JP2002251150A - Image recording and display device - Google Patents

Abstract

(57) [Problem] To provide a writable and erasable color image display device by ink jet recording provided with a waste ink treatment layer. SOLUTION: A granular glass coated with a photocatalyst (titanium oxide) is disposed in a waste ink treatment layer, and organic substances in the waste ink are decomposed by ultraviolet irradiation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording and displaying apparatus having an ink jet recording means, a medium writable by the ink jet means, and an erasing means for erasing an image recorded on the medium. The present invention relates to an apparatus having a processing reaction tank.

[0002]

2. Description of the Related Art In general, there are image display apparatuses mainly for displaying moving images, such as CRTs and liquid crystal displays, which are display apparatuses such as computers.
On the other hand, there is a display device which repeatedly displays and deletes a large screen still image like a poster or a bulletin board. An example of this display device is an information board that displays destinations and information in a station yard. As a similar device, an electronic blackboard used for a meeting, a meeting, or the like can be given.

In recent years, an increase in paper consumption and an increase in power consumption for image display have become problems in terms of resource saving and environmental destruction. In order to solve these problems, there is a demand for the latter still image display device which consumes less power and drastically reduces paper consumption.

[0004] The conventional CRT and liquid crystal display, which are moving picture display devices, have a problem that as the size increases, the price of the device increases. Further, since power is used to maintain a display state even when a still image is displayed for a long time, there are many problems in terms of power consumption. Recently, many large and low power consumption type display devices such as a plasma display (PDP) have been developed and commercialized, but they are still expensive and
This is a display device for displaying a moving image like a CRT, and is not suitable for a long-time display of a still image.

As a display device for recording and erasing a still image display on the same medium, a computer or the like records an electrostatic latent image corresponding to an image signal on a special medium, develops the image with magnetic toner, and displays the information. The board has been commercialized. If the electrostatic image on the medium is removed, the image adhered and developed on the special medium is removed, and a new image can be repeatedly recorded. The only problem with this information board is that it is difficult to colorize it using magnetic toner.

On the other hand, although the method of use and purpose are different from those of the above-described display device, a still image (character) written by hand is displayed, the displayed content is read by a scanner, and a hard copy is recorded after taking a hard copy. There is an electronic blackboard device as a device for erasing a blackboard with a blackboard eraser. This device is useful in terms of reducing paper consumption and power consumption. However, there is currently no product that is connected to a computer or the like to record and display a still image and to automatically erase a written image. The development of an electronic blackboard device with an image erasure has been conventionally performed. For example, JP-A-61-9071, JP-A-5-597, and JP-A-5-14.
564, JP-A-5-160940, JP-A-5-1624
94, JP-A-6-32095, JP-A-6-48091,
Proposals as shown in JP-A-6-87295 and JP-A-6-245008 have been made. According to the above-mentioned invention, a method similar to an electrophotographic photosensitive member cleaning apparatus used in a copying machine such as a cleaning fur brush or a rubber blade for removing characters and images handwritten on a medium of a conventional electronic blackboard by a writing instrument for the electronic blackboard. Has proposed a device for wiping and erasing. However, with respect to the image writing unit, only the handwriting is performed with a writing instrument as in the related art.

The requirements for a still image information display device are as follows:
It is not only a stand-alone device in a conference room like an electronic blackboard, but also has a function as a display device in a network, and can display information from a remote place sequentially. It is hoped that it can be displayed.

Further, in such an apparatus, it is desired that the apparatus is provided with a facility for treating effluent and a waste liquid in consideration of reduction in environmental load.

[0009]

In a conventional image display device, the only device that can perform writing and erasing based on information from an external image input device is a magnetic recording type information board. However, colorization is difficult because magnetic toner is used, and an image display device capable of displaying a color image and recording and displaying a high-quality image has been desired.

[0010] Accordingly, the present applicant mounts an ink jet recording apparatus on a recording medium similar to an electronic blackboard as a system capable of displaying a color image, writes an image on the medium, displays the image, and performs the above-described erasing method. A prototype of an image recording and display device capable of erasing images was studied. At that time, the erased waste ink needs to be treated so as not to burden the environment. Also in the present apparatus, when the ink used in ink jet recording is discharged as waste ink, an image recording apparatus having a reaction tank capable of appropriately processing the waste ink is required. An image recording apparatus having such a waste ink treatment reaction tank was studied.

In the ink jet recording method, recording is performed by flying small ink droplets and attaching the ink to a recording medium such as paper. Ink used in the conventional inkjet recording method is generally an ink containing water as a main component, and a water-soluble high-boiling solvent such as Glycol for the purpose of preventing drying and preventing nozzle clogging. is there.

When ink-jet recording is performed on a recording medium similar to a conventional electronic blackboard, it has been impossible to write and record using conventional ink-jet ink. In general, as a medium used for an electronic blackboard, a sheet in which a fluorine compound-based film or the like is stuck on a milky white base film is used. With a blackboard pen using water-based ink, when an image is written on a blackboard, the moisture is evaporated, and a resin film containing a release agent and a pigment remains, so that it can be easily wiped and erased with a cloth, felt, sponge, or the like. . In addition, the surface tension of the medium surface is set small so that the medium can be easily erased. Therefore, there is a problem that when recording is performed with ink jet ink, the ink is repelled on a conventional recording medium and image recording cannot be performed. Further, if the surface tension of the medium is made larger than that of the conventional one, there arises a problem that the erasing device such as a blade cannot perform sufficient erasing.

In order to achieve the above object, the present inventors have improved the conventional ink jet recording means, solved the problems which were impossible with the conventional ink jet recording means, and recorded on a display medium. Provided is an image recording and displaying apparatus provided with a waste ink processing reaction tank capable of easily performing image erasure by an erasing member after displaying an image and easily processing waste ink discharged upon erasure.

In the ink-jet recording method, since the ink is water-soluble, a problem such as poor water resistance or bleeding (migration) occurs in a medium such as paper. Therefore, in order to solve these problems, development for improving the fixing property has been performed. In recent years, various fixing methods have been proposed to increase the water resistance of the ink. Among them, there has been proposed a method in which a liquid for improving an image is attached to a medium in advance of ink ejection. In particular, an improvement in fixability has been observed by recording a liquid containing an organic compound having a cationic group on a medium and then using an ink containing an anionic dye.

In the present invention as well, by using the above-described recording method using ink, it is possible to perform good recording without repelling the ink on the display medium. Further, it has been found that there is a combination that not only improves the fixability to the display medium, but also enables good cleaning by the erasing member between the recording method and the selected display medium.

That is, the present invention provides an ink set comprising an adhesive ink containing an ink set in which a treatment liquid containing at least a cationic substance is combined, a display medium combined with the ink set, an ink jet recording means and an erasing means. As for the image recording and displaying apparatus, there is a problem in processing waste ink. Water containing organic substances, especially coloring water containing coloring components such as printing inks, printer inks and dyes, has a high degree of coloring even in a trace amount, and not only contaminates equipment and facilities, but also is difficult to handle during work. It is necessary to perform a decolorization process. Conventionally, as a decolorizing method, activated carbon adsorption method, coagulation sedimentation method, decomposition by microorganisms, oxidation by ozone or hydrogen peroxide and the like have been performed.

However, each of these methods
There is a problem in terms of cost, treatment efficiency, and the like, and the decolorizing treatment of the colored water has been a heavy load.

[0018]

That is, the present invention has been made to solve the above-mentioned problems, and an image is formed on a recording medium by discharging recording ink for image formation based on recording data. In an image recording and displaying apparatus having a recording means for forming a recording medium and an erasing means for erasing an image recorded on the recording medium, the processing of ink on the recording medium discharged together with erasing, that is, waste ink, can be performed simply and at low cost The apparatus is provided with a waste ink treatment reaction tank capable of treating waste ink, and is characterized in that an optical semiconductor catalyst is used for waste ink treatment.

According to the present apparatus, even if the ink used is not a solution but an emulsion, it can be used, and is widely applied regardless of the form of the ink. In addition, while the contact area between the reaction phase and the photocatalyst powder increases when the particle diameter of the photosemiconductor catalyst decreases, it becomes difficult to collect or remove the photosemiconductor catalyst particles by filtration or centrifugation after the reaction, In order to completely separate and collect these, a large-sized separation device is required. Further, even when the fine particles of the photosemiconductor catalyst are separated using various types of membranes, it is necessary to periodically exchange or wash the membranes so that the membranes are not clogged.

For this reason, an apparatus incorporating a photocatalyst dispersed in a resin solution to form a film or a photocatalyst film formed on the surface of a plate-like substance using a sol-gel method or a binder method and incorporating them is also considered. However, since the contact area is smaller than that of the powdery photocatalyst, the catalytic effect is reduced.

As a result of intensive studies to solve the above-mentioned problems, the present invention has revealed that a titanium oxide coating is applied to a granular substrate in order to maximize the contact area of the photocatalyst in the waste ink treatment reaction tank. Use the one laid in the processing tank. At this time, a base material that transmits ultraviolet light of 400 nm or less, for example, quartz glass is used as the base material so that the photocatalyst is efficiently irradiated with ultraviolet light. The production method is as follows: after coating the titania sol on a granular substrate having a particle size of several mm to several tens of mm, gradually from room temperature to 600 ° C. to 7 ° C.
A titanium oxide thin film is manufactured by heating to 00 ° C. and firing. Waste ink treatment that can effectively decompose and remove organic compounds dissolved in water by the redox effect of electrons and holes generated by irradiating light, and maintain the effect without maintenance. An object of the present invention is to provide an image display device having a reaction tank.

The mechanism of the photocatalytic reaction by titanium oxide in the present invention can be considered to proceed as follows. Photon absorption is performed on the surface of the TiO ₂ crystal by ultraviolet irradiation, and two electrons jump out from one O ²⁻ ion. These electrons move freely in the lattice,
^Reduces Ti ⁴⁺ ions to Ti ³⁺ . The ^O2- ion from which two electrons have jumped out becomes an O atom. This atomic oxygen performs an oxidizing action. In terms of the formula, O ²⁻ + hν → O + 2 (e) ⁻ 2TiO ⁴⁺ +2 (e) ⁻ → 2Ti ^3+, that is, 2TiO ₂ + hν → Ti ₂ O ₃ + 〇.

The surface of TiO ₂ thus photoexcited has a very strong oxidizing power of +3.0 V and can be decomposed even by an organic substance such as plastic.

According to the present invention, by contacting titanium oxide, which is a photo-semiconductor catalyst, with colored water containing a printing ink or a dye, etc., and irradiating light, the ink or the like in the colored water is utilized by utilizing the strong decomposition ability of the photocatalyst. Is decomposed to decolorize colored water and to make it colorless and transparent. Furthermore, not only coloring components in water but also organic solvents and the like can be simultaneously decomposed, so that there is no need for reprocessing and BOD can be reduced. In addition, as in the decomposition method using microorganisms, temperature,
There is no need to strictly adjust conditions such as PH. Since the photocatalyst repeatedly acts semipermanently, there is no waste such as activated carbon after use unlike the activated carbon treatment method, frequent maintenance and regeneration equipment are not required, and the cost is very small. Further, there is an advantage that the photocatalyst such as titanium oxide is harmless and inexpensive and is easy to handle.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described, and the present invention will be described in more detail. FIG. 1 is a schematic front view of the image recording / display apparatus of the present invention, and FIG. 2 is a schematic side view.

The waste ink treatment reaction tank which is the center of the present invention is designated by reference numeral 42 in the figure. The photocatalyst irradiates light having energy equal to or greater than the band gap to generate holes having strong oxidizing power and electrons having reducing power inside. The generated electrons and holes move to the semiconductor surface, and the electrons are used for a reduction reaction and the holes are used for an oxidation reaction, so that organic substances can be decomposed. Generally, various metal oxides such as titanium oxide, tungsten oxide, zinc oxide, iron oxide, strontium titanate, cadmium sulfide, and molybdenum sulfide, and metal sulfides are known as semiconductor photocatalysts. It is preferable to use titanium oxide having a higher oxidizing power and a higher ability to decompose organic substances.

The titanium oxide used in the present invention is obtained by coating a granular substrate having a particle size of several mm to several tens mm with a titanium oxide thin film in order to increase the efficiency of the reaction. The material of the base material is so that ultraviolet light is efficiently irradiated to the photocatalyst,
A base material that transmits ultraviolet light of 400 nm or less, for example, quartz glass is used. The coating is performed by dip coating using a titania sol and then heating and gradually increasing the temperature from room temperature to a final temperature of 600 ° C to 700 ° C.

The titania sol is prepared by suspending ultrafine titanium oxide in water or hydrolyzing an alkoxide of titanium obtained by a reaction of alcohol with titanium tetrachloride or titanium metal. that time,
When alcoholamines such as diethanolamine and triethanolamine are added, a uniform and transparent titania sol is obtained, and by using the same, a high performance titanium oxide thin film photocatalyst can be produced.

In this manner, the titanium oxide thin film coated on the obtained granular substrate has an anatase crystal form. The firing conditions are directly performed at a temperature of 600 ° C to 700 ° C, or the firing temperature is lower than 600 ° C,
When the temperature is higher than 700 ° C., only a titanium oxide thin film mixed with rutile or amorphous which has low activity as a photocatalyst can be obtained.

In order to further improve the performance of the titanium oxide photocatalyst used in the present invention, platinum, rhodium,
A metal film such as ruthenium, palladium, silver, copper, iron, and zinc may be coated.

Examples of a method for coating the surface with these metal films include a photoelectrodeposition method, a CVD method, and a PVD method such as sputtering or vacuum deposition. In this case, if the thickness of the metal film is too large, the cost increases, and light hardly reaches titanium oxide. Therefore, the thickness of the metal film is preferably as thin as possible.

The thus-obtained titanium oxide thin film photocatalyst 62 used in the present invention is spread in the reaction tank 42, water is introduced from the water supply port 63, and a certain amount of ink is collected in the reaction tank and peeled and erased. A diluted solution having a concentration of about 100 ppm is prepared. Thereafter, by irradiating ultraviolet rays of 400 nm or less, the organic compounds in the ink waste liquid can be easily and continuously decomposed and removed. Therefore, the decolorized waste water can be directly discharged from the drain port 64 as the discharge water. it can. At this time, the waste ink is vibrated by the ultrasonic generator 65, so that the waste ink can be more efficiently processed. In addition, it has many advantages that it can be used at low cost, energy saving and maintenance-free only by irradiating light.

In the present invention, the light irradiating means 66 has a low pressure, a high pressure, and a high pressure in order to enhance the decomposition ability of the photocatalyst, rather than using a light source mainly including a visible light region such as a solar heat, an incandescent lamp, a fluorescent lamp, and a halogen lamp. It is preferable to use a light source device such as a high-pressure mercury lamp or a xenon lamp, which has a short wavelength of 400 nm or less and contains many wavelengths in an ultraviolet region having a large energy because the processing speed can be increased.

The image recording and displaying apparatus comprises an image writing section 1, a recording medium driving section 2, a display section 3, and an image erasing section 4.
Reference numeral 70 denotes a housing, which supports each part. Recording medium 10
The sheet (hereinafter, referred to as a sheet) is endlessly stretched by rollers 11 and 12 rotatably supported on a housing side plate (not shown). 13 and 14 are roller shafts of the respective rollers. The sheet driving unit 15 has a built-in stepping motor, transmits driving to the roller shaft 14, and drives the sheet 10. 28a and 28b are sheet guides for preventing the sheet 10 from skewing.

The image writing section 1 includes a recording head unit 20 and a carriage 21 on which the recording head unit 20 is mounted. The recording head unit 20 includes a guide shaft 22 and a guide shaft 23. FIG. 3 is a detailed schematic view of the image writing unit, and FIG. 4 is a schematic view from below the recording head. The carriage 21 is
It is configured to be movable in a direction determined by the two guide shafts 22 and 23, and scans the recording area on the sheet 10 back and forth. On the carriage 21, a recording head unit 20 including a recording head group 24 that discharges a plurality of color inks and processing liquids, and an ink tank 25 that supplies ink and processing liquid to each recording head 24 is mounted. The plurality of color inks mounted on the image display device are four colors of black (Bk), cyan (C), magenta (M), and yellow (Y). At the lower right of the front right end of the area where the carriage 21 can move, there is a recovery system unit 26 at the bottom,
An ink suction unit and a wiping unit for capping the ejection portion of the recording head 24 with a cap member (not shown) at the time of non-printing, and for cleaning the nozzle 27 or the vicinity of the nozzle of the recording head 24 are mounted.
Usually, the position where the recording unit 20 is located on the recovery system unit 26 is called the home position of the recording head 24. Black (Bk), cyan (C), magenta (M), and yellow (Y) colors and a recording head group 24 that discharges a processing liquid, a processing liquid tank 25a, a Bk tank 25b, a C tank 25c, and a M tank The tank 25d and the Y tank 25e are mounted. Each tank is connected to the printhead group 24 via a connection with the printhead group 24, and supplies ink and processing liquid to the ejection ports.

FIG. 4 is an enlarged view of the front surface of the recording head group. The recording head group 24 includes a head 24a for discharging the processing liquid and a head 24 for discharging the Bk ink.
and heads for discharging cyan, cyan 24c, magenta 24d, and yellow 24e. Each head is held by the recording unit 20. Each head is composed of 256 nozzles 27.

Next, the processing liquid will be described. When a treatment liquid is used, the treatment liquid contains at least a cationic substance, and further contains finely ground cellulose.
The function of the processing liquid containing a cationic substance at the time of image formation will be described below. For simplicity of explanation,
A case where recording is performed using a dye ink containing a water-soluble dye containing an anionic group will be described, but the same applies to a case where recording is performed using a pigment ink containing an anionic compound and a pigment. The treatment liquid contains an anionic compound, for example, when used with an ink containing a dye as a coloring material, when mixed with the ink on a sheet, the first step of the reaction is the cationic liquid contained in the treatment liquid. The low molecular weight component of the substance and the anionic compound in the ink are associated by ionic interaction, and the dye in the ink is instantaneously aggregated and separated from the solution phase. Next, as a second stage of the reaction, an aggregate of an anionic compound and a low molecular weight cationic substance is adsorbed by finely ground cellulose (preferably having an average particle diameter of 5.0 μm or less) contained in the treatment liquid. As a result, the size of the aggregate of the dye formed in the above-mentioned association is further increased, and as a result, solid-liquid separation is performed. In this state, the liquid portion has a role of a portion to be fixed on the sheet, and has a feature that the image is easily erased, which will be described in detail later. Further, the aggregate formed by the low molecular weight component of the cationic substance, the anionic dye, and the finely ground cellulose not only satisfies the condition for appropriately fixing to the sheet due to the increase in the viscosity thereof, but also the image on the sheet. The image does not flow due to dripping. Further, even if migration is caused by leaving for a long period of time, and dots are not mixed with each other even if they are formed of different color inks of adjacent dots, the phenomenon of bleeding (bleeding) of ink at the boundary surface between different color images does not occur. That is, it is possible to form a high-quality image that can be erased and does not cause migration, bleeding, or dripping on a sheet, which is impossible with a commonly used inkjet ink.

The above-mentioned cationic substance contained in the processing solution,
JP-A-8-7 describes finely-divided cellulose and other inks containing anionic groups corresponding to additives and processing liquids.
2393, and from there,
What is necessary is just to use the ink set of an ink and a processing liquid.

Next, the sheet 10 on which an image is written by the writing unit will be described. In the apparatus of the present invention, EMMA was most suitable as the sheet surface material capable of performing the best writing and erasing with the ink set. Further, among the sheets considering erasing, it was found that a sheet having a porous shape in which the dye penetrates into the sheet surface was not suitable for the present display device, and a sheet having a smooth surface was suitable for writing / erasing. .

Next, the image display unit 3 will be described. The images sequentially written by the image writing unit 1 are conveyed by driving of the sheet driving unit 2 in the direction of arrow A in the figure. When the desired image has been written, the image is displayed at an appropriate display position on the image display unit. A support plate 33 is provided on the back surface of the sheet 10 so that the sheet 10 does not loosen.

Next, the image erasing section 4 will be described. FIG. 5 is an enlarged schematic view of the image erasing section 4. The image erasing unit 4 mainly includes a detachable blade 40 for wiping and erasing ink on the sheet 10, a blade support plate 41, and a waste ink processing reaction tank 42 for accumulating and accumulating the erased ink and thereafter processing the waste ink. In addition, a cleaning roller 43 and a cleaning roller shaft 44 are provided for improving the cleaning on the sheet.

The blade separation / contact means is a plate-like blade 40 made of an elastic material such as urethane rubber and having substantially the same width as a sheet.
And a blade support plate 41 on which a blade is mounted, blade support plate rotating means 45, a tension spring 46 and a solenoid 47. The blade supporting plate rotating means 45 includes a supporting plate 48 having a rotating shaft 49, a connecting rod 50 and a blade supporting plate 41.
And a plunger 51 connected to the solenoid 47 is fixed to the center of the connecting rod 50.
The rotating shaft 49 is rotatably supported by a frame (not shown). The solenoid 47 is fixed to a frame (not shown), and the plunger 51 is rotatably attached to the center of the connecting rod 50. One end of the tension spring 46 is attached to a part of the support plate 48, and the other end is attached to a frame (not shown). As a result, the blade 40 rotates and moves away from the sheet 10.

The cleaning roller 43 is made of a polyurethane sponge or the like, and is composed of a cylindrical porous roller 43 and a roller shaft 44 substantially equal in width to the sheet 10, and is supported by a frame (not shown) to be rotatable. ing. The driving of the roller 43 is transmitted from the driving unit 2 that drives the sheet driving roller 12, and is rotated so as to be opposed to the traveling direction A of the sheet 10 (counter direction). If this is the case, it will be completely removed.

According to the above configuration, after an image is formed on the sheet by ink jet recording, display is performed, and furthermore,
The created image could be deleted as needed.

A display / operation panel for directly giving instructions to the apparatus and for displaying the state of the apparatus on a monitor is provided below the display section in FIG.

Next, the operation of the image display device of the present invention will be described.

FIG. 6 is a block diagram of an image recording and displaying apparatus applicable to the present invention. Character and image data to be recorded (hereinafter referred to as image data) are input to a receiving buffer 101 of the recording apparatus from a host computer 100. You.
Further, data for confirming whether or not data is correctly transferred, data for notifying the operation state of the recording and display device, and the like are returned from the recording and display device to the host computer 100. The data in the reception buffer 101 is transferred to the memory unit 103 and temporarily stored in a random access memory (RAM) under the control of a control unit 102 having a CPU. The mechanical control unit 104 drives a mechanical unit 105 such as a carriage motor or a sheet feed stepping motor according to a command from the control unit 102. Sensors,
The switch control unit 106 sends a signal from a sensor including various sensors and switches, and a signal from the switch unit 107 to the control unit 102. Display element control unit 108
Is the LE of the display panel group according to the command from the control unit 102.
It controls the display element unit 109 including D, a liquid crystal display element, and the like.

The print head controller 110 controls the print head 111 according to a command from the controller 102.
Further, temperature information indicating the state of the recording head 111 is sensed and transmitted to the control unit 102. The image processing unit 112 processes the image data input to the reception buffer 101, and generates data for recording.

Hereinafter, a recording / display erasing operation using the image display / recording apparatus will be sequentially described with reference to FIG. When the power is turned on by turning on an unshown device switch (S1),
Drive unit 2 The sheet drive motor operates (S2), and sheet 1
0 is sent in the arrow direction A in FIG. When the sensor 53 detects the marker 52 provided at the end of the sheet 10 (S3), the sheet 10 stops (S4). The image writing section 1 performs the following initial operation of the writing section (S5). After the recovery system cap of the recovery system unit 26 is released, the home position of the head unit 20 is detected. After detecting the head home position, the recovery system unit performs an initial operation of the recording head by suctioning ink from the head and wiping operation. When the initial operation is completed, the control unit waits for a recording signal (S6). When the control unit receives the input signal of the recording signal, a signal is sent from the mechanical control unit to the solenoid 47 before the printing by the recording head 24 starts, and the blade 40 and the cleaning roller 43 are brought into contact with the sheet 10 (S7).

When the above operation is completed, preparation for writing is made. The host computer 100 corrects the image to be displayed to the size of the sheet 10, and transmits an image signal. At this time, unlike a normal printer, an image is developed so that a signal is sent to a recording head so that printing is performed from below the image so that the image can be observed from the front of the apparatus. When a recording signal is sent to the recording head group 24, black, cyan, magenta, and yellow inks and a colorless processing liquid are respectively ejected from the recording head. Further, prior to the ejection of the recording ink, the treatment liquid is ejected and attached to at least a portion where the recording ink of each color adheres to the sheet. In the present embodiment, the recording head group 24 is composed of five recording heads. However, the present invention is not limited to this. Is also good. Further, the head arrangement is not limited to the head arrangement of the present embodiment, and the head arrangement of each color ink and the processing liquid,
The number can be freely selected.

When the recording signal is transmitted, the recording head 24 prints on the sheet 10 along the guide shafts 22 and 23. The recording head 24 is fed stepwise according to the width of the recording head for each reciprocation. When printing is started, the sheet drive motor is repeatedly driven and stopped according to the sheet feed amount in the direction A in the drawing, and ink is ejected from the nozzles of the recording head during the time when the sheet is stopped, and printing is performed on the sheet 10. Perform (S8). When the printing of the image on the display area is completed (S9), the following write section ending operation is performed (S10). The recording head 24 returns to the home position, performs a cleaning operation by the recovery unit 26, and the recording head 24 is capped by the cap unit. At the same time, the solenoid 4
7, a signal is sent to the blade 40, and the blade 40 is separated from the sheet 10 (S11).

If the image recording is completed (S12), the power is turned off.
FF (S13) and the apparatus stops. Next, in order to record and display a new image, the process returns to S5, and a new recording is started. The previous image erasing method has a mode in which the recording head 24 records and simultaneously erases the previously recorded image at the same time as recording and a mode in which only the recorded image is erased. Selection can be made by instructing 100. In the erasing only mode, the erasing mode can be selected from a display / operation panel attached to the exterior of the apparatus (not shown).

Examples of the present invention will be described below.

Example 1 Titanium tetraisopropoxide was diluted with isopropanol, hydrochloric acid and diisopropanolamine were added with stirring to prepare a transparent sol solution, and granular quartz having a particle diameter of 5 mm was obtained by dip coating. The surface of the glass was coated with a titanium oxide film.
After drying this, it was heated and gradually heated from room temperature to 630 ° C. and fired. This was repeated five times to form a 0.5 μm titanium oxide film on the surface of the quartz glass particles. This is applied to the waste ink treatment reaction tank 4 in the image display device shown in FIG.
2

Next, the following liquid composition A and ink B were used.
Was adjusted. Components of Liquid Composition A First, after mixing and dissolving the following components, the mixture is further pressure-filtered through a membrane filter (trade name: Fluoropore Filter, manufactured by Sumitomo Electric) having a pore size of 0.22 μm, and the pH is 4.8. Was obtained.・ Benzyltri-n-butylammonium chloride (molecular weight: 311) 5.0 parts ・ Theolus cream (average particle diameter 3.5 μm) [Asahi Kasei, microcrystalline cellulose, 10% slurry] 10.0 parts ・ Diethylene glycol 10.0 parts -75.0 parts of ion-exchanged water Preparation of ink B Next, the following components were mixed, and the pore size was further reduced to 0.22.
The solution is filtered under pressure through a μm membrane filter (trade name: Fluoropore Filter, manufactured by Sumitomo Electric Industries, Ltd.), and contains yellow, magenta, cyan containing an anionic group-containing dye whose pH is adjusted to 4.8. Black inks Y1, M1, C1, and B1 were obtained. This Y1, M1, C1
And B1 were ink B.

(Yellow ink Y1) C.I. I. Direct Yellow 86 2 parts ・ Thiodiglycol 10 parts ・ Acetyleneol EH 0.05 parts ・ Ion exchange water 87.95 parts (Magenta Ink M1) ・ C.I. I. Acid Red 289 2.5 parts ・ Thiodiglycol 10 parts ・ Acetyleneol EH 0.05 part ・ Ion exchange water 87.45 parts (cyan ink C1) ・ C.I. I. Acid Blue 9 2.5 parts-Thiodiglycol 10 parts-Acetyleneol EH 0.05 parts-Ion exchange water 87.45 parts (black ink B1)-C.I. I. Food Black 2 4.0 parts ・ Thiodiglycol 10 parts ・ Acetyleneol EH 0.05 parts ・ Ion-exchanged water 85.95 parts Using the liquid composition A and the ink B of the present example obtained as described above. An ink set was constructed, injected into an ink cartridge, and image recording and erasing were performed using the image recording and display device shown in FIG. The waste liquid of the used ink peeled and erased from the ink layer used in the present embodiment was treated with a treatment reaction tank in which silica glass particles coated with titanium oxide prepared as described above were spread and several hundred ppm.
Water was added so that the ink concentration became about the same, and waste ink treatment was performed as follows. The aqueous solution at this time was dark purple. The ink aqueous solution was irradiated with light from a 100 W high-pressure mercury lamp by flowing cooling water using a light source having a lamp installed in a quartz inner cylinder.

At this time, in order to increase the decomposition efficiency, the entire tank was vibrated by ultrasonic vibration. After about 20 spectral irradiations, the color of the aqueous solution that was dark purple disappeared, and became visually colorless and transparent.

(Example 2) As in Example 1, granular quartz glass coated with titanium oxide was spread over a waste ink treatment reaction tank. Next, the same liquid composition A as in Example 1 and the following ink B were prepared.

(Yellow ink Y) C.I. I. Direct Yellow 86 3 parts ・ Diethylene glycol 10 parts ・ Isopropyl alcohol 2 parts ・ Urea 5 parts ・ Acetyleneol EH 1 part ・ Ion exchange water 79 parts (Magenta Ink M) ・ C. I. Acid Red 289 3 parts ・ Diethylene glycol 10 parts ・ Isopropyl alcohol 2 parts ・ Urea 5 parts ・ Acetylene EH 1 part ・ Ion exchange water 79 parts (cyan ink C) ・ C.I. I. Direct Blue 199 3 parts ・ Diethylene glycol 10 parts ・ Isopropyl alcohol 2 parts ・ Urea 5 parts ・ Acetylene EH 1 part ・ Ion exchange water 79 parts (black ink Bk) ・ C.I. I. 3 parts of food black 2-10 parts of diethylene glycol-2 parts of isopropyl alcohol-5 parts of urea-1 part of acetylenol EH-79 parts of ion-exchanged water The ink set of the present embodiment obtained as described above is formed, and the ink cartridge is formed. After the injection, image recording and erasing were performed in the same manner as in Example 1 using the image recording and displaying apparatus shown in FIG.

Water was added to the used ink peeled and erased from the ink layer used in the present embodiment so that the ink concentration became about several hundred ppm using a waste ink treatment reaction tank in the same manner as in the first embodiment to prepare an aqueous solution. Thereafter, waste ink treatment was performed as shown below. The aqueous solution at this time was dark blue. Here, using a light source in which a lamp was installed in an inner tube made of quartz, light of a high-pressure mercury lamp of 100 W was irradiated while flowing cooling water. At this time, the entire tank was vibrated by ultrasonic vibration to increase the decomposition efficiency. After about 30 spectral irradiations, the color of the dark blue aqueous solution disappeared, and the solution became visually colorless and transparent.

[0061]

The image display apparatus provided with the waste ink treatment tank provided by the present invention decomposes organic substances such as dyes in water by utilizing the strong decomposition ability of the photocatalyst and decolorizes colored water. Can be. In addition to coloring components in water,
Organic solvents and the like can be decomposed at the same time to reduce BOD. In addition, photocatalysts such as titanium oxide are harmless, inexpensive, and act semipermanently repeatedly, so that they are easy to handle, do not generate waste or sludge, and do not require maintenance or regeneration equipment. According to the present invention, it has become possible to provide an image display device that addresses environmental issues.

[Brief description of the drawings]

FIG. 1 is a schematic front view of an image recording and displaying device of the present invention.

FIG. 2 is a schematic side view and a front view of an enlarged portion of the image recording and displaying device of the present invention.

FIG. 3 is a detailed schematic diagram of an image writing unit of the image recording / display device of the present invention.

FIG. 4 is a schematic diagram of the image recording and displaying apparatus of the present invention as viewed from below a recording head.

FIG. 5 is an enlarged schematic view of an image erasing section of the image recording and displaying apparatus of the present invention.

FIG. 6 is a block diagram of an image recording and displaying device applicable to the present invention.

FIG. 7 is a flowchart illustrating an example of a recording / display erasing operation of the image recording / display apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image writing part 2 Recording medium drive part 3 Display part 4 Image erasing part 10 Recording medium 11, 12 Roller 13, 14 Roller shaft 15 Sheet drive part 20 Recording head unit 21 Carriage 22, 23 Guide shaft 24a, b, c, d And e recording head group 25: ink tank 25a processing liquid tank 25b black tank 25c cyan tank 25d magenta tank 25e yellow tank 26 recovery system unit 27a, b, c, d, e nozzle 28a, b sheet guide 33 Support plate 40 Blade 41 Blade support plate 42 Waste ink treatment reaction tank 43 Cleaning roller 44 Cleaning roller shaft 45 Blade support plate rotating means 46 Tension spring 47 Solenoid 49 Rotating shaft 50 Connecting rod 51 Plunger 60 Marker 61 Sensor 62 Photocatalyst 63 Water supply port 64 Drain port 65 Ultrasonic wave generator 66 Light irradiation means (light source) 67 Valve 68 Pump 70 Housing 100 Host computer 101 Receiving buffer of recording device 102 Control unit 103 Memory unit 104 Mechanical control unit 105 Stepping motor, etc. Mechanism section 106 sensor, switch control section 107 switch section 108 display element control section 109 display element section 110 head control section 111 recording head 112 image processing section

Claims (10)

[Claims] 1. An image recording and displaying apparatus comprising: recording means for forming an image on a recording medium by discharging recording ink for image formation based on recording data; and erasing means for erasing an image recorded on the recording medium. An image display device, comprising: a reaction tank for performing waste ink treatment using an optical semiconductor catalyst. 2. The image display device according to claim 1, wherein the photosemiconductor catalyst comprises a solid catalyst, titanium oxide (TiO ₂ ). 3. The image display device according to claim 2, wherein the crystal form of the titanium oxide is anatase. 4. The photo-semiconductor catalyst has a particle size of several mm to several tens m.
2. A titanium oxide thin film coated on a granular substrate of m with a titania sol.
The image display device as described in the above. 5. The image display device according to claim 1, further comprising an ultraviolet light source having a wavelength of 400 nm or less. 6. The image display device according to claim 4, wherein the granular substrate is a substrate that transmits ultraviolet light having a wavelength of 400 nm or less. 7. The image display device according to claim 1, wherein the photosemiconductor catalyst is laid in the reaction tank. 8. The image display device according to claim 1, wherein the reaction vessel is provided with a low-pressure / high-pressure and ultra-high-pressure mercury lamp or a xenon lamp. 9. The image display device according to claim 1, wherein the reaction tank is provided with a water supply port, a drain port, and an ultrasonic generator for vibrating the treated water. 10. The image display device according to claim 1, wherein the waste ink is an aqueous ink composed of a treatment liquid containing a cationic substance and an ink containing an anionic dye.