JPH06130857A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an erasable image and a preserving image with one device by providing a decoloring toner in at least one of developing devices and arranging the developing device in the upstream of an image forming process to other developing devices. CONSTITUTION:The developing device 2 arranged in the upstream of the image forming process to the developing device 6 has a developer 5 provided with the decoloring toner and the developing device 6 has a developer 9 provided with normal nondecoring toner. When the erasable image is selected for instance, the developing device 2 approaches up to the position where development can not be attained of a photosensitive body 1 by the rotation of a cam 10, the developing device 6 is separated to the position where the development can not be attained of the photosensitive body 1 by the rotation of a cam 11 and the decoloring toner stuck to a magnet roller 3 is stuck to the electrostatic latent image of the photosensitive body 1. On the other hand, when the preserving image is selected, the developing device 6 approaches the photosensitive body 1, the developing device 2 is away from the body 1, and the decoloring toner stuck onto a magnet roller 7 is stuck to the electrostatic latent image of the photosensitive body 1 and developed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a printer and other image forming apparatus using an electrophotographic system.

[0002]

2. Description of the Related Art In recent years, due to the rapid development of electronics, a great deal of information can be quickly obtained, and although it is said to be paperless, information can be printed on paper using an image forming apparatus such as a printer or a copying machine as in the past. It is generally done to confirm. Therefore, the amount of paper used increases with the increase in the amount of information, and the processing thereof has become a major social problem from the viewpoint of environmental protection.

However, most of these prints are not records required to be preserved, but most of them are transient,
Most of them are abandoned in a short period of time.

Against this background, it has been proposed in the Journal of the Electrophotographic Society, Vol. 31, No. 2 (1992) to use a decolorizable toner as a toner of a conventional image forming apparatus. The decolorizable toner is a color that is decolorized by light of a specific wavelength, and by using this, it is possible to erase unnecessary printed matter and reuse the paper.

[0005]

However, the decolorizable toner is not suitable for long-term storage because it is unstable with respect to light and the like. Therefore, in view of environmental protection, two types of image forming apparatuses are required, an image forming apparatus having a developing device provided with a decolorizable toner and a normal non-decolorizable toner, and for the user, the image forming apparatus is required. This imposes inconveniences such as the cost of purchase and expansion of the equipment installation location.

Further, when two types of developing devices, that is, a developing device provided with a decolorizable toner and a developing device provided with a normal non-decolorable toner are provided in one image forming apparatus, the development is A small amount of normal toner is mixed in the developing device provided with the decolorizable toner. Therefore, when the printed matter printed with the decolorizable toner is tried to be erased, some portions cannot be erased.

In view of the above points, the present invention provides an image forming apparatus capable of forming both an erasable image and an image for storage by one unit.

[0008]

SUMMARY OF THE INVENTION The present invention is an image forming apparatus having a plurality of developing devices each having a different type of toner, at least one of the developing devices having a decolorizable toner. It is characterized in that the developing device provided with the color toner is arranged upstream of the image forming process with respect to the other developing devices.

[0009]

Since the image forming apparatus of the present invention has the developing device equipped with the decolorizable toner and the developing device equipped with the normal non-decolorizable toner in one unit, the purchasing cost is reduced for the user. You can save space.

In the image forming apparatus having a plurality of developing devices, the toner of the upstream developing device is easily transported to and mixed in the downstream developing device. If a developing device equipped with decolorizable toner is placed upstream of the image forming process with respect to other developing devices, normal non-decolorable toner may mix into the developing device equipped with decolorizable toner. Therefore, the unerasable portion does not occur in the printed matter printed using the decolorizable toner.

On the contrary, although the decolorizable toner is mixed in the developing device provided with the non-decolorizable toner, there is no problem in terms of image because it is a small amount.

By arranging the developing device provided with the decolorizable toner upstream of the image forming process with respect to the other developing devices, the erasable image and the storable image can be stored at a low cost without increasing the number of parts. Both of the images for use can be formed well.

[0013]

First, the structure and image forming process of an example of an image forming apparatus (copier) of the present invention will be described with reference to FIG.

The recording papers stored in the recording paper cassette 18 are pulled out one by one by a paper feed roller (not shown) and conveyed to the front of the transfer charger 13. Photoconductor 1
Rotates at a constant speed by a rotating mechanism (not shown). The photoconductor used is a conventional organic material type photoconductor (OPC).
The photoconductor 1 is charged by the discharge from the corona charging device 5. An electrostatic latent image of the document 17 guided by the light source 16 and the optical system 19 is formed on the charged photoreceptor 1. On the other hand, this copying machine has two developing devices 2,6. The developing device 2 has a developer 5 having a decolorizable toner, and the developing device 6 has a developer 9 having a normal non-decoloring toner. In each developing device, the toner on the magnet rollers 3 and 7 is appropriately sent from the toner tank (not shown) to the developing devices 2 and 6 and agitated by the agitating rollers 4 and 8 so as to have a predetermined density. At this time, the toner is charged with the opposite polarity to the charging potential of the photoconductor. The charged toner adheres to the magnet rollers 3 and 7 and is carried to the body surface side with the photoconductor 1.

An erasable image or a stored image is selected by a changeover switch provided on an operation panel (not shown). For example, if you select an erasable image,
The rotation of the cam 10 causes the developing device 2 to approach the position where the photoconductor 1 can be developed (the surface of the photoconductor 1 and the magnet roller 3).
(The distance from the surface is 1 mm), and the rotation of the cam 11 causes the developing device 6 to move to the non-developable position of the photoconductor 1 (the distance between the photoconductor 1 surface and the magnet roller 7 surface is 5 mm). Here, the decolorizable toner that has adhered to the magnet roller 3 adheres to the electrostatic latent image on the photoconductor 1 and is developed. Conversely, when the stored image is selected, the developing device 6 approaches the photoconductor 1, the developing device 2 moves away from the photoconductor 1, and the non-erasable toner adhering to the magnet roller 7 becomes electrostatic on the photoconductor 1. It is attached to the latent image and developed.

The recording paper is transferred onto the transfer charger 1 at a timing corresponding to the developed image position on the photosensitive member 1.
3 is transported. At this time, a voltage having a polarity opposite to that of the toner is applied to the transfer charger 13. Therefore, the toner on the photoconductor 1 is transferred onto the recording paper.

The toner on the recording paper is nipped and conveyed by a heat roller 20 and a pressure roller 21 having a heater inside, and during this time, the toner is fused and fixed on the recording paper and the image formation is completed.

On the other hand, the photosensitive member 1 is then removed by the charge removing charger
The toner that has been discharged by 4 and has not been transferred on the photoconductor 1 is removed from the photoconductor 1 by the cleaner 15.
The decolorizable toner used in this example is 100 parts by weight of styrenacryl resin, 2 parts by weight of a commercially available charge control agent, 1.5 parts by weight of polypropylene wax, 1 part by weight of polyethylene wax, 4 parts by weight of cyanine dye as a colorant. Parts, and 2 parts by weight of an organic boron ammonium salt as a decoloring aid are mixed and kneaded, pulverized, and then 0.2 parts by weight of silica is added to obtain an average particle diameter of 10.0 μm.

In a series of image forming processes along the rotation direction A of the photosensitive member starting from the charging of the photosensitive member 1 as described above, the developing device 2 provided with the decolorizable toner 5 as shown in FIG. The developing device 6 is arranged upstream of the image forming process.

As a result, the usual non-erasable toner is not mixed into the developing device 2 provided with the erasable toner, so that an unerasable portion is generated in the printed matter printed with the erasable toner. Never.

On the contrary, the decolorizable toner is mixed in the developing device provided with the non-decolorizable toner, but since it is a small amount, there is no problem on the image.

In this way, both the erasable image and the image for storage can be satisfactorily formed at low cost without increasing the number of parts.

[0023]

According to the present invention, it is possible to provide an image forming apparatus capable of excellently forming both an erasable image and an image for storage by one unit.

[Brief description of drawings]

FIG. 1 is a schematic view of an image forming apparatus showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2, 6 Developing device 5 Developer with decolorizable toner 9 Developer with non-decolorable toner

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshitaka Urata 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Yoshiaki Akazawa 22-22 Nagaike-cho, Abeno-ku, Osaka, Osaka Within the corporation

Claims (1)

[Claims] 1. An image forming apparatus having a plurality of developing devices, each of which has a different type of toner, wherein at least one of the developing devices includes a decolorizable toner, and the developing device includes a decolorizable toner. Is arranged upstream of the image forming process with respect to another developing device.