JPS6370260A - Reversal image copying method - Google Patents

Abstract

PURPOSE:To easily form a varicolored reversal image with an ordinary copying machine by the constitution consisting in transferring and fixing the toner image of an original image onto diazo photosensitive paper by a white toner, then coloring said image in a developing stage. CONSTITUTION:A non-image part causes photodecomposition and is not colored and an image part is not photodecomposed when a developing device contg. the white toner is mounted to the ordinary copying machine and the image is exposed to the diazo photosensitive paper through a light-transparent original. A diazonium salt forms an azo dye by a coupling reaction and the image is colored when the photosensitive paper is immersed in a developing soln. such as alkali soln. The varicolored reversal image is easily formed by the ordinary copying machine by which the positive image is easily obtd. from the negative original.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a reverse image copying method for obtaining a reversed image of an original image, and more specifically relates to an electrophotographic copying machine of a normal normal image copying system. The present invention relates to a copying method for obtaining a reversed image using a diazo developing mechanism.

(Prior Art and its Problems) In the electrophotographic copying method, in addition to the usual positive image copying system that forms a positive electrostatic latent image from an original to obtain a positive copy, it also uses a negative original such as microfilm or a laser beam copying system. There is a reversal image copying system in which a negative electrostatic latent image is formed by a light image such as a beam or a light emitting diode play and then reversed to obtain a positive copy.

A typical copying machine is equipped with only a positive image copying system, and is premised on obtaining a positive original with a white background from an original with a white background. Therefore, it is not possible to obtain a positive white background image from a black background image. However, some slides and some foreign pamphlets or catalogs have negative images, making them difficult to read.
It is desired to reproduce these images as positive images.

In recent years, copying machines that have both a normal image copying system and a reversed image copying system have been proposed, and the mechanisms employed in these machines can be broadly classified into the following two types.

One method uses a photoreceptor and a charging device that can be charged to both positive and negative polarities (pi-charge), and a toner that has frictional charging characteristics, and in the case of positive image copying, the charge on the photosensitive layer is In this method, development is carried out by making the polarity opposite to that of the toner, and in the case of reversal image copying, making the polarities the same and applying a bias voltage to the developing section. However, there are only a limited number of photoreceptors that can be charged to both polarities, which not only limits their sensitivity and durability, but also affects the sensitivity and other electrophotographic properties of the photoreceptor when charged positively and negatively. There are so many differences that it is very difficult to adjust the density and image quality of the normal image and the inverted image to a constant value.

Another method is to use a photoreceptor that can be electrically charged, and to form an electrostatic latent image by charging and imagewise exposure. In the case of reversal image formation, reversal development is performed by applying a bias to the developing section using toner of the same polarity as the electrostatic latent image. This method uses two types of toner, one for the normal image and one for the reverse image, and further requires electrical control such as switching the application of a bias voltage to the developing section. As described above, a copying machine having both a normal image copying system and a reverse image copying system requires a very complicated mechanism and control.

Therefore, a simple method for obtaining a reversed image using a normal copying machine is to copy an image onto colored paper using white toner. However, black paper generally contains carbon for the purpose of improving color development and preventing static electricity. Therefore, the entire paper becomes conductive, making it unsuitable for use as transfer paper for electrostatic transfer type copying machines.

In addition, using a copying machine with a built-in developing device equipped with black toner and white toner, first, the black toner is transferred to the entire surface of the white transfer paper, and then the obtained black copy paper is further fed to create the original. A method has been proposed in which a reverse image is formed by forming an image corresponding to the image using white toner. This method has the advantage of being able to transfer reliably with a simple configuration, but has the disadvantage that the paper passes through the fixing device twice, causing wrinkles and curls.

Also, in order to transfer white toner over black toner,
White toner is required to have strong hiding power.

Therefore, it is difficult to completely hide the black color of the base, and a bright white color cannot be obtained. Furthermore, it is difficult to uniformly transfer black toner over the entire surface, making it impossible to obtain a clear image.

(Object of the Invention) The present invention has been made to solve the above-mentioned problems, and its purpose is to provide an electrophotographic copying method for obtaining an inverted image of a document image using an electrophotographic copying machine and a diazo developing mechanism. It's about doing. Another object of the present invention is to provide a method for easily and reliably obtaining a reversed image using diazo photosensitive paper. Still another object of the present invention is to provide a method for forming various reversal images using a combination of toner and diazo photosensitive paper. Still another object of the present invention is to provide a copying method that can produce clear reversed images without wrinkles or curls on the paper.

(Structure of the Invention) In order to achieve the above object, the present invention uses diazo photosensitive paper as a transfer paper for an electrophotographic copying machine, and transfers and fixes a toner image corresponding to a document image using white toner onto the diazo photosensitive paper. After that, the diazo photosensitive paper is subjected to a diazo development process to develop color, thereby forming an inverted image of the original image.

(Example) Examples of the present invention will be described in detail below.

The electrophotographic copying machine used in the present invention is generally used and does not have a special mechanism for forming a reverse image, but the developing device is configured to have toner of each color built-in and is replaceable. ing.

For this reason, it is desirable that the developing device be integrated into a unit.

When performing the copying method of the present invention, a developing device containing white toner is attached to the main body of the copying machine, and diazo photosensitive paper is used as transfer paper. Diazo photosensitive paper generally has a photosensitive layer consisting of a diazonium salt and a cuff puller formed on a base paper. When irradiated with light, diazonium salts photodecompose into phenol, but this photodecomposition product is colorless and does not become colored under the influence of light, heat, oxygen, etc. When this diazo photosensitive paper is subjected to image exposure through a light-transmitting original, the portion corresponding to the non-image area undergoes photodecomposition and is not colored. On the other hand, since the portion of the diazo photosensitive paper corresponding to the original image is not irradiated with light, photodecomposition does not occur. Next, this diazo-sensitive paper is added to a developer consisting of an alkaline solution or the like, whereby the diazonium salt causes a coupling reaction and is colored to form an azo dye. As a result, an image corresponding to the original image is formed on the diazo photosensitive paper. In some diazo photosensitive papers, a one-component diazo photosensitive layer containing only a diazonium salt is developed with an alkaline solution containing a coupler.

In addition, development methods include wet development in which the film is immersed in an alkaline solution, semi-dry development in which the film is coated with an alkaline solution, and dry development in which it is exposed to ammonia gas.

The principle of forming a reversed image by using this diazo photosensitive paper as a transfer paper will be explained.

By performing a normal copying operation, a white toner image corresponding to the original image is transferred and fixed onto the diazo photosensitive paper. Next, this diazo photosensitive paper is loaded into a diazo developing mechanism.

At this time, the exposure mechanism of the diazo copying machine is not involved in the present invention, so only the development mechanism is necessary. The diazo photosensitive paper attached to the developing mechanism has not been exposed to light, so the diazonium salt causes a coupling reaction and develops color. However, the area to which the white toner is attached cannot be developed. Because it does not come in contact with the liquid, it does not react and does not develop color. Even if it develops color, the color tone is much weaker than the black toner used in electrophotographic copying machines, so even white toner with somewhat weak hiding power is sufficient. Therefore, for example, the white character information section stands out from the blue colored background section, thereby obtaining an inverted image of the original image.

To prepare the white toner used in the present invention, a binder resin,
A white colorant and other compounding agents such as a charge control agent and a release agent are used, and the composition thereof is not particularly limited as long as it does not adversely affect the color tone of the toner. The ratio of the white colorant to the binder resin is generally 2:100 to 35:
It is preferable that the weight ratio be 100. If the weight ratio is less than this, the white toner will not be able to hide the background area, and if it is more than this, the triboelectric charging characteristics of the toner will deteriorate, and furthermore, spent toner will be likely to be generated, so that it cannot be used as a developer. lifespan becomes shorter.

As the binder resin used in this toner, various resin materials conventionally known as toner binder resins for electrophotography are used. For example, polystyrene, polystyrene
Styrenic copolymers such as butadiene copolymers, styrene/acrylic copolymers, ethylene copolymers such as polyethylene, polyethylene/vinyl acetate copolymers, polyethylene/vinyl alcohol copolymers, phenolic resins, epoxy resins, allyl phthalate resins, polyamide resins, polyester resins, maleic acid resins, etc.

The white coloring agents used in this toner include zinc white,
Titanium oxide, tin oxide, antimony white, zinc sulfide, zinc oxide, barium carbonate, clay, silica, white carbon, talc, alumina, pallite, etc. are used.

As the charge control agent used in this toner, a known colorless or white one is used as it does not adversely affect the color tone of the white toner. For the purpose of positive charge control, organic compounds having basic nitrogen atoms, such as basic dyes, aminopyrine, pyrimidine compounds, polynuclear polyamine compounds, aminosilanes, or fillers surface-treated with these, are used. For the purpose of controlling negative charge, a carboxyl group-containing compound such as a metal chelate of alkyl salicylic acid is used. These charge control agents are preferably used in an amount of 1 to 10% by weight per toner.

Further, as the mold release agent used in this toner, silicone oil, low molecular weight olefin resins, various waxes, etc. are used.

The white toner is obtained by melting and kneading the above components, cooling them, and then crushing and classifying the mixture. It can also be obtained by dispersing toner ingredients in a resin solution and then spray granulating the resultant.

The commonly used diazo photosensitive paper is strong enough to be transported by electrophotographic copying machines, so there is no risk of wrinkling or curling, and it also has sufficient insulation for electrostatic transfer. Therefore, there is no problem with transfer efficiency.

In the method of the present invention, a reversal image was formed using white toner, but white in the present invention is not limited to pure white, and may include red, yellowish, or other colored tones. It is also considered a white toner. Further, the color of the toner is not limited to this. Toners with high brightness, such as light colors such as yellow, pink, and light blue, are also used, and transparent toners are also preferably used. Diazo-sensitive paper that develops various colors has also been developed, and by combining toner and diazo-sensitive paper, colorful copies can be obtained, making it possible to use a variety of copying applications.

(Effects of the Invention) With the copying method according to the present invention, a reversed image can be easily formed by using an electrophotographic copying machine and a diazo developing mechanism, so a copy of a positive image can be obtained from a negative original and is always easy to read. It becomes a copy.

Furthermore, a reversed image can be easily and reliably formed using diazo photosensitive paper.

Furthermore, if a document from a thermal transfer printer or facsimile is lost, a positive image can be obtained by copying from a transfer film containing a negative image of the tube used to create the document, making it possible to reproduce the document, which is convenient.

Furthermore, a clear reversed image can be obtained without wrinkles or curls on the copy.

Furthermore, if a negative image can be obtained from a positive original, various applications such as design, advertising, printing, etc. can be considered.

Claims (1)

[Claims] Diazo photosensitive paper is used as a transfer paper for an electrophotographic copying machine, and after a toner image corresponding to the original image is transferred and fixed using white toner onto the diazo photosensitive paper, the diazo photosensitive paper is subjected to a diazo development process to develop color. A reversed image copying method for forming a reversed image of a document image by