JPS59228257A - Display device - Google Patents

Abstract

PURPOSE:To avoid damaging of the surface of an image bearing body and to permit its repeated uses for a long term in a display device for forming on said body a toner image corresponding to an information signal through repeating formation, display, and erasion of images, by giving said body a specified surface hardness. CONSTITUTION:A photoconductor layer 44 is formed on a transparent electrically conductive substrate 43 consisting of a base sheet 41 and a transparent conductive layer 42 to prepare an image bearing endless belt 4. It is moved in the arrow direction and imagewise exposed with laser beams L from an imagewise exposing device 10 from the side of the base sheet 41, and at the same time as an image formed at the preceding cycle is erased, a toner image is formed and displayed on the layer 44 with a developing device 13. The belt 4 to be used for said device has a surface hardness of >= pencil hardness F (JIS TESTING METHOD STANDARD K-540) on the image bearing side.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides visual recognition of, for example, electrical image information that is calculated or read out from an electronic computer or image reading device, image information that is stored as a soft copy on magnetic tape or microfilm, etc. The present invention relates to an image display device that reproduces and displays images as images that can be produced, or that is attached as an image monitor to image forming-related equipment such as copiers and office automation equipment.

t7] More specifically, as a display image, on the surface of the image carrier that is properly rotated,
The present invention relates to an improvement of the image carrier of the five apparatuses for creating a toner image and displaying the image in response to the input of the various information signals mentioned above.

Conventionally, CRT display devices, liquid crystal display devices, etc., have been widely used as image display devices, but these display devices do not necessarily have sufficient resolution9 display screen size or visibility. I can't say that. For example, if we look at recent developments in office automation equipment, we can see that the display screens required for word processors, microfilm retrieval machines, and optical disc memory monitors are high-fine still images, while CRTs and LCDs have flicker-free images. Alternatively, it is difficult to say that it is appropriate because of the visual angle dependence.

The present invention proposes a method of repeatedly forming toner images on a display screen as a device particularly suitable for displaying high-quality still images. Various methods can be applied to the means for creating a toner image in response to an information signal. For example, a method of forming a toner image at the same time as exposure using a photovoltaic layer as an image carrier (Japanese Patent Application No. 1974-1982) issue),
There is also a method of obtaining an electrostatic charge image on a dielectric belt of an image carrier using a pin electrode and converting it into a toner image (Utility Model Application No. 57-5506
1) Another method is to use an easily magnetized stylus to visualize magnetic powder or magnetic fluid toner on the surface of an image carrier according to a magnetization signal.

In any case, it is easy to understand that these displayed images have higher image quality than ordinary electrophotography, electrostatic printing, and magnetic printing, since they do not involve a transfer process. Furthermore, compared to the CRT and liquid crystal display devices mentioned above,
Since the image quality is comparable to that of printing, it can be said that Bamboo Shizu IJ: is excellent in image display.

On the other hand, there is a possibility of problems with display devices using toner PIJ images.
Because the carrier is used repeatedly, toner and the coloring materials used in it gradually adhere to the N m i & t4 display surface, resulting in non-image 1
There is a possibility that the $ portion will be significantly contaminated. That is, in this method of display, a latent image is formed on an image carrier by converting an information signal into light such as a laser beam, or time-series signals such as voltage or current, and
This is followed by a step of developing with toner and visualizing it. When the displayed image is no longer needed, it goes through an erasing step and then repeats the same process to create an image pattern on the same image carrier surface and display it repeatedly. Therefore, contamination on the surface of the image carrier significantly impairs image quality and has been a major obstacle to putting this type of display device into practical use.

Electrophotographic copying, which was mentioned earlier, is a method of obtaining images using a similar process.
There is an apparatus that creates a toner image on an intermediate master such as electrostatic printing or magnetic printing and transfers this onto plain paper or the like to obtain a printed image. The intermediate master used in these printing devices is used repeatedly, and even if the surface of the intermediate master itself becomes contaminated, as long as it does not affect the transferred image, there is no problem in practical use. It can be said that the characteristics are essentially different from the characteristics of the image carrier used in the apparatus.

The present invention is intended to improve the stain resistance of the surface of an image carrier used in the above-mentioned image display device.

Toner, image bearing surface, and image forming factors that cause contamination9
This can be improved as a comprehensive technology that adds β-1 to the erasing process, but if the surface roughness of the image bearing member is measured and the surface smoothness exceeds a certain level, it is possible to improve the repeating process. To provide a contamination image display device with respect to the number of times the image is displayed. Another purpose is to provide high stability and high durability for use in devices that create and display toner images on display surfaces.
8! The purpose is to provide a counterpart.

The characteristics and effects of the image carrier of the present invention will be described in detail below. As an example of an image display device using a toner image,
FIG. 1 shows a method using an optical 4' fMa layer as an image carrier.

FIG. 1 shows the poles (approximately t1
Vertical cross section showing the structure (11, 11 side view. 1 is a vertical device exterior box, 2 is a display image viewing window formed with a thick (opening) on the front panel of the exterior box, generally made of a glass plate etc. A transparent plate 3 is stretched.

Reference numeral 4 denotes an endless belt type photoreceptor (image carrier) stretched between a driving pulley (or roller) 5 and a driven pulley (or roller) 6, which are horizontally installed in the upper and lower parts of the outer box.

(hereinafter simply abbreviated as belt). For example, as shown in the second figure, the belt is made by coating a metal or metal oxide (indium oxide, tin oxide, chromium oxide) on the outer surface of a transparent and strong base sheet material 41 such as a synthetic resin sheet or film. A transparent conductive substrate Jvi43 is formed by forming a transparent conductive layer 42 by thin (vapor deposition), and a photoconductor /144 is laminated on the conductive layer 42 surface by a coating method, a vapor deposition method, etc. The outer peripheral surface of the belt 4 is the photoconductor layer surface.The belt 4 is rotated in the direction of the arrow by the rotation of the drive pulley 5, and the tension side outer surface of the belt 4 moves from the bottom to the top of the display image viewing window 2. pass.

Reference numeral 10 denotes an optical device using a light beam scanning method, which is arranged in the space between the tension side belt portion and the slack side belt portion of the rotating belt, and includes a half-47 body laser (or It consists of a gas laser), a polygon mirror, an fθ lens, etc.

Then, a time-series electrical digital pixel signal S is inputted from an image reading device, electronic computer, etc. (not shown in the figure), and a laser beam L that has been changed in accordance with the signal is transmitted to a driven pulley 6.
oscillate in the direction. The oscillated beam is mirrored 1 on the way.
1 Back side part A of the driven goo 96 of the tension side belt
The slit 12a of the slit plate 12
The back surface portion A of the belt is scanned and misted in the width direction of the belt. The scanning of the laser beam in the belt width direction is defined as a main scanning, and the movement of the belt 4 is defined as a sub-scanning, whereby the back surface of the belt 4 is sequentially exposed to light images.

Reference numeral 16 denotes a developing device disposed at a position on the front side of the belt corresponding to the back side part A of the belt that receives the laser beam scanning exposure;
Reference numeral 4 denotes a lamp for irradiating the entire surface with light, which is disposed downstream of the exposure area A on the back side of the tension side belt in the direction of belt movement.

The illustrated developing device 16 includes a developer storage box 15 and a box 1 thereof.
A rotary developing sleeve 16 made of a non-magnetic material such as stainless steel or aluminum, which is horizontally disposed inside the box 5 and has its left side half circumferential surface exposed to the outside from inside the box, and a magnet row 217 that is inserted and built into the sleeve 16. It consists of a developer applying blade 18 to the outer surface of the sleeve and a developer (conductive magnetic toner) T housed in a box 15. The conductive magnetic toner T in the box 15 is attracted by the magnetic field of the magnet row 217 inside the sleeve, and is held on the outer peripheral surface of the sleeve as a magnetic adsorption layer, rotating together with the sleeve, and the toner near the rotating developing sleeve 16 is attracted by the magnetic field of the magnet row 217 inside the sleeve. At step 18, the layer thickness is regulated and the toner layer is leveled, and the toner leveling surface comes into contact with and passes through the belt surface portion corresponding to the belt back surface light image exposure area A by rotation of the sleeve.

A DC bias is applied between the conductive layer 42 on the side of the belt 4 and the developing sleeve 16, and E indicates the power source.

Therefore, when the image is displayed on the exposed area A on the back side of the belt 4 while the belt 4 and the developing device 13 are driven, the image is displayed on the front side of the υ belt according to the principle described later. The conductive toner on the sleeve 164till adheres to the sleeve 164till in a resistive manner to form a toner image corresponding to the exposed image. The belt surface on which the toner image has been formed is rotated to a position within the range of the image viewing window 2 and once stopped. As a result, an image is displayed on the second window. After a predetermined period of time has elapsed, or by operating the belt re-rotation button, the belt 4 is rotated again and the next display image is moved to the window 2 section, and the belt is temporarily stopped and the image is displayed. By repeating this process, multiple images are sequentially displayed.

After the image display ends, the belt rotates and the developing device 1 is turned on again.
The displayed toner images on the belt surface that have reached the three positions are removed from the belt lfe surface by the developing and cleaning action of the developing device and are collected into the developing device fill. On the belt surface from which the toner image has been removed, toner images corresponding to the light image exposure pattern in the exposure area A are successively formed, and as the belt 40 rotates, the toner images are transferred to the second display window. do.

The entire surface light irradiation lamp 14 passes through the light image exposure portion A 17 and irradiates light uniformly in the width direction on the back side of the belt on which the toner image is formed on the surface t11], thereby exposing the inside of the non-electric material 44 at the end of the belt 4. It is arranged to separate the electrical status of each part.

The formation of the toner image on the belt surface is performed without charging and at the same time as the photoimage exposure, and the principle thereof will be explained with reference to FIGS. 6 and 4. For convenience of explanation, it is assumed here that the photoconductor layer 44 of the belt 4 is of N type, and that a negative bias is applied to the conductive layer 42 and a positive bias is applied to the developing sleeve 16.

At the light image exposure area A on the back side of the belt, the exposed bright area (A(L)
, FIG. 6) passes through the transparent substrate layer 46 and enters the photoconductor layer 44. Electron-hole pairs are generated in the portion of the photoconductor layer 44 where the light is incident, and electrons C of these are attracted by the negative bias of the belt conductive layer and the positive bias of the developing sleeve and move toward the surface side of the photoconductor layer 44. and move. Along with this, the electroconductive toner in the coating layer of the toner on the developing sleeve 16 side that comes into contact with and passes through the belt surface area corresponding to the light image exposure area A(L) on the back side of the belt is exposed to the transferred electrons e and opposing charges. A positive charge is generated. Then, due to the Coulomb force between the electron C and the positive charge induced toner, the positive charge induced toner adheres (Ta) from the developing sleeve 16 side to the belt surface side. The positive side of the attached toner Ta is exposed in the dark area (A (DI, Fig. 4).
), due to the bias between the conductive layer 42 of the belt 4 and the developing sleeve 16 and the capacitance between the conductive layer 42 and the conductive toner layer on the developing sleeve 16 side, the conductive layer portion and the surface toner of the conductive toner layer are respectively Although positive and negative charges are induced, the Coulomb force acting between them is weak (therefore, toner hardly adheres to the surface of the belt 40).

Therefore, without charging the surface of the photoconductor layer 44 of the belt 4, toner M (Ta) is selectively applied only to the surface portion of the photoconductor layer corresponding to the bright area of the photoimage exposure simultaneously with the photoimage exposure. ) to form a toner image.

In addition, the toner image that has been rotated to the developing device 16 after being displayed is easily removed from the belt surface by being rubbed by the toner layer held on the sleeve 16 side, and is deposited within the toner layer held by the sleeve. It is captured, collected, and used repeatedly to form toner images.

The method of displaying an image by forming a toner image on the surface of an image carrier using a light 4 camera as described in 5 above has a high resolution, for example, a CRT display device or a display device using liquid crystal. The image is easy to see because it is a still image and does not flicker, and has little angle dependence like a liquid crystal display (less eye strain. For those that require a displayed image, the toner image formed on the belt surface It has the advantage that a hard copy can be easily obtained by adding a mechanism for transferring the image to the copy paper surface.

Particularly, as in the above-mentioned example, a non-charged and photo-simultaneous toner image forming system in which both development and cleaning are performed has an extremely simple device configuration and is highly practical.

In addition to the laser beam scanning method in the above example, 1 optical image exposure device [10] includes an LF3D array device, liquid crystal, P
It is also possible to use a shutter array that selectively transmits LZT or white light. It may also be a fog light device using X4;l. In this case, the base layer 46 of the belt 40 does not have to be transparent to visible light, as long as it is transparent to X-rays. or,
The image carrier used in Kisei EjFJ includes the photoconductor layer 4 described above.
A layer (not shown) can be formed on top of 4. Examples of this surface include polymethyl methacrylate resin, acrylic polyol 41 resin, urethane-modified polybutadiene n+1)ms saturated polyester ipano, acrylic-modified silicone, alginate-modified silicone, polyether sulfone, styrene-methyl methacrylate copolymer, etc. It can be formed by scanning the dispersed crane obtained by dispersing the light Mi='tM on the body layer 44.

The display ↓ position explained above can be done by using a light guide (1 layer) or (1) for the 14-day break, but it is also possible to use a signal input method other than light by using a bin'#:゛ζ A method of forming an electrostatic charge image on a special layer to form a toner image, or a method of using magnetic toner and inputting a current signal to an easily magnetizable stylus to form a magnetic toner image can be similarly applied. .

In single-image display devices using these toner images, after repeated use, many scratches occur on the surface of the image carrier, and stains occur due to image defects and toner embedding in the scratches. increases, and the image quality tends to deteriorate significantly. There are various possible causes of scratches on the surface of the image carrier, but -
As a result of examining the hardness of the surface of the image carrier as a factor, it was found that when the pencil hardness of the surface of the image carrier is at least a certain value, no deterioration in image quality due to scratches occurs.

That is, J18 (Japanese Industrial Standards) test method standard -5400
It has been found that it is necessary for the measured pencil hardness to be F or higher in order to prevent image defects and toner contamination due to the occurrence of scratches.

As will be described in detail in Example 1, using the display device shown in FIG. 1, the number of repeated uses and image quality of two types of image bearing belts having different pencil hardnesses were investigated.

The pencil hardness of the produced belt is (A) 2H (corresponding to the curve in Figure 5) and (B) B (corresponding to the curve in Figure 5).
%lB). The toner used at this time was 1 part of methyl methacrylate fat 40% and 60% magnetite.
This is a conductive magnetic toner that is prepared by melting and mixing parts by weight, pulverizing the toner, and adhering conductive carbon fine powder to the surface in a hot air stream.

Changes in base density for each belt were measured using a reflection densitometer, and the maximum and minimum values were plotted in FIG. 5, and the average values were connected by a curve. In addition, a visual inspection of the belt revealed that there was an overall increase in dirt during the early stages of repeated use, and that after about 2,000 uses, the image was rough and there were five black spots in the conveying direction of the belt. Streaks began to appear, and then the black streaks became clear and tended to spread throughout the belt.No such black streaks were observed in Belt 4.

It is clear from Figure 5 and the visual results that the hardness of the lead part is 2H.
Belt (A) had a slight deterioration in image quality, but Belt (B), which had a pencil hardness of B, had a significant deterioration in image quality and was not suitable for practical use.

Considering this result, it can be seen that the surface of the image carrier comes into contact with the conductive magnetic toner in the developing device, as explained above in the image display principle. (B) As shown in (B), the surface of the image carrier with low pencil hardness is prone to scratches due to contact with toner, and the scratches accumulate toner contamination that cannot be erased, increasing the base density and making the image rough. It can be determined that image quality deterioration such as black streaks along the transport direction occurs.

Therefore, it is possible to compare the appropriate hardness by preparing various samples with different pencil hardnesses and examining changes in base concentration and occurrence of black streaks.

As a result, it was necessary to have a pencil hardness of F or higher.

As is clear from the above description, in the present invention, in an apparatus that creates a toner image and displays an image, in order to maintain stable image quality, the surface of the image carrier is small (and has a pencil hardness as shown in the claims). This is based on the fact that we found that F or higher is necessary.

This result relates only to the surface of the image carrier and toner development, and can be said to be effective for all display devices, regardless of the image forming method. Therefore, the present invention is not limited to the embodiments shown below.

(Example 1) According to the following steps, a photoconductive image-bearing belt (see FIG. 2)9 The image-bearing belt in this example has a two-layer structure, that is, a transparent conductive base film is coated with a photoconductive image-bearing belt (see FIG. 2). It is formed by coating a photoconductor layer and an interface layer.

The transparent conductive base film is manufactured by Daicel Chemical Industries, Ltd.
CELEC-KEe manufactured by CELEC was used.

In addition, the photoconductor layer coating liquid and the surface layer coating liquid are the following W
Obtained by performing t adjustment.

1) Photoconductor layer coating solution Doped with Cu and In to form a semiconductor laser (820-
) is sensitive to 100 parts by weight of CdS powder and the average molecular! A dispersion liquid of 7 parts by weight of polybutyl methacrylate (10,000 ml) was made into a dispersion liquid with methyl ethyl ketone, and the mixture was kneaded with a roll mill to obtain a coating liquid.

2) 30 parts by weight of surface layer coating liquid TjOv M material and 44 parts by weight of acrylic polyol (Hytaloid 5340 manufactured by Hitachi Chemical Co., Ltd.) were added with xylene, and the solution with a solid content ratio of 60 parts by weight was mixed in a sand mill dispersion machine ( 2000 rpm) for 20 hours, and 6 weights of isocyanate V polymer (Kaban Takenate D-11ON, Kurade Pharmaceutical Co., Ltd.) was added to this solution to prepare a coating solution.

The TiQt pigment was added to increase the whiteness of the image display surface and to adjust the electrical resistance of the surface layer.

Then, a surface layer was applied using a roll coater to obtain a dry film thickness of 15 microns, thereby obtaining an image bearing belt.

The pencil hardness of this image bearing belt was measured according to JIS test method standard -5400. The pencil hardness was 2H.

The belt is suspended and driven on the image display device shown in FIG.
Image display was performed repeatedly using the method described above. The toner powder used was one prepared by the method described above.

As shown in FIG. 5(A), this image bearing belt showed no deterioration in image quality even after repeated display (Comparative Example 1) The following surface layer was formed on the photoconductor layer prepared in Example 1. Ties Pigment 4 forms a surface layer with a dry film thickness of 5 microns using a coating solution.
A liquid having a solid content of 20% by weight was prepared by adding 4 parts of the pigment (CM-8000) and 30 parts by weight to ethyl alcohol. This solution was dispersed for 5 hours using a ball pot to obtain a coating liquid.

The pencil hardness of this image bearing belt was B. The base concentration for repeated use of this belt was not desirable as shown in FIG. 5(B).

(Example 2) On the photoconductor layer produced in Example 1, a surface layer having a dry thickness of 11 mm and 15 microns was formed using the following surface layer coating solution.

(Surface layer coating liquid) A liquid having a solid content ratio of 35 parts by weight was prepared by adding 60 parts by weight of butyl acetate. Spread this solution using a sand mill disperser (
2000 rpm) for 5 hours to prepare a coating solution.

The pencil hardness of this image bearing belt was F.

Example 1 In the same manner as in Example 1, changes in base density and image quality were observed in repeated cycles. The change in base density after turning the edges 5,000 times was 0.05, and no deterioration in image quality such as blemishes or black streaks was observed.

(Examples 6 to 8) The resins and solvents shown in Table 1 were used in place of the urethane-modified polybutadiene and butyl acetate used in Example 2 on the optical fiber layer prepared in Example 1. A surface layer was formed in the same manner as in Example 2. Table 1 shows the pencil hardness of each belt and the change in base density after repeated use.

Table 1 (Comparative Examples 2 to 6) On the photoconductor layer prepared in Example 1, the resins and solvents shown in Table 2 were used in place of the urethane-modified polybutadiene and butyl acetate used in Example 2. A surface layer was formed in the same manner as in Example 2. Table 2 shows the lead can hardness of each belt and the change in base concentration during repeated use.

Table 2 (Example 9) Crys on polyester film as image bearing belt
A magnetic tape provided with a thin film was coated with the surface smoothing layer shown in Example 1 to a dry film thickness of 10 microns. The surface hardness of this image bearing belt was similar to that of Example 1.

The image forming process using this belt had the same configuration as the apparatus shown in Fig. 1, except that instead of a laser scanner, a magnetic head was installed in front of the developing station A to generate a barcode pattern signal. A magnetized lh image was created by inputting the following information. or,
In the Momonzoiso in Figure 2, this was intended for the Emperor so as not to disturb magnetic development. The 4i and JL toner images created with this device had sufficient contrast to be recognized by the OCR head.

The erasing process is carried out by thermally quenching the back side of the image carrying belt. In this (...), 19 Il
l J', 'J belts always provided stable OCR, resistance, and confidence in the case of edge-backed production.

4. fjit fn Lilingming of the drawings 1st diagram: A very schematic configuration diagram of an example of a display device, 2nd diagram:
[゛I 1 is Dl, image jf: 2 f! FIG. 6 is a schematic diagram showing the principle of image formation in the exposed bright portion, and FIG. 4 is a schematic diagram showing the principle of image formation in the exposed dark portion. Mushi 5 is a statue JL! It is an explanatory diagram showing a change in pace density when using a continuous repetition 1--FIG.

Shi-1-1) q Procedural amendment (voluntary) August 1, 1980 Commissioner of the Patent Office Kazuo Wakasugi 1 Indication of the case 1981 Patent Application No. 103172 2,
Invention title display device 3, relationship with the case of the person making the amendment Patent applicant Address: 3-30-2 Shimomaruko, Ota-ku, Tokyo Address: m146 3-30-25 Shimomaruko, Ota-ku, Tokyo, subject of amendment (1) Details Book 6, Contents of amendment (1) The scope of claims is amended as shown in the attached sheet.

(2) "On the other hand," from page 3, line 19 to page 5, line 1 of the specification
A display device using toner images can be said to be based on a different perspective. "On the other hand, there are problems with display devices that use toner images.

As the same carrier is used repeatedly, many scratches occur on the surface of the image carrier, and stains increase due to image defects and toner embedding in the scratches, which tends to significantly degrade image quality. That is, displaying using this method consists of a step of forming a latent image on an image carrier by converting the information signal into light such as a laser beam or time-series signal such as voltage or current, and then developing it with toner to make it visible. When the displayed image is no longer needed, it goes through an erasing step and then repeats the same process to create an image pattern on the same image carrier surface and display it repeatedly. Therefore, contamination caused by scratches on the display surface of the image carrier or toner embedded in the scratches significantly impairs image quality.
This has been a major obstacle in putting this type of display device into practical use.

Electrophotographic copying, which was mentioned earlier, is a method of obtaining images using a similar process.
There is a device that creates a toner image on an intermediate master such as electrostatic printing or magnetic printing and transfers it to plain paper etc. to obtain a print.The intermediate master used in these printing devices cannot be used repeatedly. However, even if the surface is contaminated, there is no practical problem as long as it does not affect the transferred image, and the characteristics of the image carrier used in the apparatus of the present invention are essentially It can be said that he takes a different perspective from the others.''

(6) ``Stain resistance'' in line 3 of page 5 above is corrected to ``scratch resistance.''

(4) On page 5, line 4 of the same page, ``It is a developmental factor'' is corrected to ``The generation is.''

(5) Same as above, page 5, line 6, ``Surface roughness'' is corrected to ``1 surface hardness''.

(6) Same as above, page 5, line 7, "smoothness" is corrected to "hardness".

(7) Insert "attributable to scratches on the surface of the image carrier" after "for" on page 5, line 8 of the same document.

(8) Same as above, page 5, line 13, "high durability" is corrected to "high scratch resistance."

λ Patent Claims Display device.

Claims (2)

[Claims] (1) An image carrier having a photoconductor layer on a substrate having a transparent conductive layer is subjected to photoimage exposure from the substrate side, and at the same time the surface of the photoconductor layer corresponding to the photoimage exposure area is exposed to light. A display device of a type that displays by forming a toner image, characterized in that the lead foil hardness measured according to the JIS test method standard -5400 on the side of the image carrier on which the toner image is formed has a hardness of 2 or more. display device. (2) The display device according to claim 1, wherein the image carrier has a light beam of 41M and a surface smooth layer on the body layer.