JPS6368857A - Copying method for reversed image - Google Patents

Abstract

PURPOSE:To easily form a reversed image without using any copying machine by applying water base ink to a copy obtained by transferring a toner image corresponding to an original image to transfer paper with white or transparent toner and fixing the toner by using an electrophotographic copying machine. CONSTITUTION:A developing device which contains the white toner is mounted on a copying machine main body and normal white transfer paper is used as transfer paper for copying operation, so that the white toner image corresponding to the original image is formed on the transfer paper. This obtained copy is coated with water base ink of desired color. The toner is made principally of resin, so no water base ink sticks on a toner part and only the background part is colored to cause the white toner image to be seen above the colored background part, thus obtaining the reversed image of the original image. Consequently, the reversed image of the original image is obtained without requiring any special device nor control mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electrophotographic copying method for obtaining a reversed image of a document image. The present invention relates to a copying method for obtaining a reversed image using the present invention.

(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 are reversal image copying systems in which a negative electrostatic latent image is formed by a light image, such as a beam or a light emitting diode array, 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, but 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 triboelectric charging characteristics with a constant thickness. In the case of positive image copying, the charged charge on the photosensitive layer is This is a method of developing by applying a bias voltage to the developing section with polarities opposite to those of the toner, or in the case of reversal image copying, with the polarities being the same. 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 uses a photoreceptor that can be electrostatically charged, and forms an electrostatic latent image by charging and image exposure, and in the case of positive image formation, it is charged to the opposite polarity to the electrostatic latent image. This is a method in which development is performed using toner, and in the case of reversal image formation, reversal development is performed by applying a bias to the developing section using toner having 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, as a simple method of obtaining a reversed image using a normal copying machine, a method of copying an image on colored paper using white toner can be considered. 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.

(Object of the Invention) The present invention has been made to solve the above problems, and its purpose is to provide a reversed image copying method for obtaining a reversed image of a document image without requiring any special device or control mechanism. There is a particular thing. Another object of the present invention is to provide a copying method for easily and reliably obtaining a reversed image using ordinary white paper. Still another object of the present invention is to provide a method of forming various reverse images by changing the color of water-based ink. Still another object of the present invention is to provide a copying method that allows a clear reversed image to be obtained even with toner having weak hiding power.

(Structure of the Invention) In order to achieve the above object, the present invention uses an electrophotographic copying machine to transfer and fix a toner image corresponding to a document image onto a transfer paper using white toner or transparent toner. The present invention is characterized in that an inverted image of the original image is formed by further applying water-based ink to the copy.

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

The 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 contains toner of each color and is configured to be replaceable. . For this reason, it is desirable that the developing device be integrated into a unit.

When carrying out the copying method of the present invention, a developing device containing white toner is attached to the main body of the copying machine, and ordinary white transfer paper is used as the transfer paper. When a copying operation is performed under these conditions, a white toner image corresponding to the original image is formed on the transfer paper. A water-based ink of a desired color is applied to the copy thus obtained.

Since most of the toner is made of resin, the water-based ink does not adhere to a portion of the toner, and only the background portion is colored. As a result, the white toner image stands out from the colored background area, thereby obtaining an inverted image of the original image. Commercially available water-based inks may be used, and by changing the color, the background image can be colored in a variety of colors, expanding the range of copying applications. It is desirable to uniformly apply a small amount of water-based ink to the entire surface, and application using a roller is preferably employed.

Since the white toner used in the present invention does not need to hide the base, it is not necessary to use a material with excellent hiding power.

A binder resin, a white colorant, and other compounding agents such as a charge control agent and a release agent are used to produce a white toner, and the composition is not particularly limited as long as it does not adversely affect the color tone of the toner. do not have.

The weight ratio of the white colorant and the binder resin is preferably 0 to 35 parts by weight of the white colorant to 100 parts of the binder resin.
If the amount ratio of the white colorant is greater than this, the triboelectric charging characteristics of the toner will deteriorate, and furthermore, spent toner will be more likely to be generated, resulting in a shortened lifespan as a developer.

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
Styrene 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.

Transparent toner is also suitably used in the copying method of the present invention.

A transparent toner is produced without adding a color pigment in a normal toner production process, but preferably one in which the addition of a white pigment is omitted in the above-mentioned white toner production process. As the binder resin, a highly transparent resin is selected, and as the charge control agent, a colorless one or a white one with weak hiding power is selected. Furthermore, even if a colored charge control agent is used after being pulverized, its hiding power will be weak.

A developing device containing this transparent toner is attached to the copying bridge body, and an image corresponding to the original image is transferred and fixed using the transparent toner. When a water-based ink is applied to the obtained copy as described above, an image is formed in which only the toner image portion is not colored. The portion where the transparent toner is fixed is visible through the paper base, resulting in an inverted image of the original image.

When transparent toner is used, the following effects are also obtained. Even if transparent toner is transferred to white paper, the image cannot be seen with the naked eye, and only appears as an entirely white paper. Therefore, confidential matters can be maintained by copying important or confidential matters onto white paper using transparent toner, storing copies, and applying water-based ink to obtain the information when necessary.

Alternatively, a copy onto which transparent toner has been transferred may be sent to a recipient, and the recipient may apply water-based ink.

In the method of the present invention, a reversal image is formed using white toner and transparent toner, but the toner colors are not limited to these.Colorful images can be created by using various colored toners and water-based inks. A copy is obtained. Furthermore, by using a copying machine that has an editing function, it is also possible to produce copies with partially different colors.

(Effects of the Invention) With the copying method according to the present invention, a reversed image can be easily formed without using a special copying machine, so a copy with a positive image can be obtained from a negative original, and the copy will always be easy to read. . Furthermore, a reversed image can be easily and reliably formed using ordinary white paper.

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

Furthermore, secret texts can be easily created.

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] Using an electrophotographic copying machine, a toner image corresponding to the original image is transferred and fixed using white toner or transparent toner onto transfer paper, and the resulting copy is further coated with water-based ink to invert the original image. A reverse image copying method for forming an image.