JPH0814727B2 - Image forming device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image forming apparatus for forming an image by printing, and in particular, a coloring material is applied onto a toner image formed and fixed on a photoconductor and the coloring is applied. The present invention relates to an apparatus for contact-transferring a material to a transfer material.

(Prior Art) Conventionally, photoengraving has been widely used in producing a printing original plate used for printing. For this photoengraving,
For example, a method of baking an optical image on a substrate coated with a photosensitive resin to make the exposed part insoluble and then washing only the part not exposed to light with a solvent to form a plate, or light irradiation. The physical property of memorizing the electrical conductivity due to
There is a method of depositing a silver image by placing the substrate in a plating bath of silver halide or the like to form a plate. However, in any of the above methods, it is difficult to recycle the plate, and it is uneconomical to discard the required number of plates after printing. Further, in the above-mentioned photolithography, since a chemical reaction is used in the intermediate step, a large apparatus such as the plating bath is required, and it takes time and cost is high.

Therefore, as an image forming apparatus using a plate that can be recycled by an electrophotographic direct plate making method, there is one disclosed in US Pat. No. 4,471,941. In this method, a fixed toner image is formed on a photoconductive substrate by an electrophotographic method, and a non-image portion (non-toner portion) on the photoconductive substrate is lubricated with fountain solution for preventing scumming. In this state, ink was applied onto the fixed toner image, and the ink was transferred to a transfer material to form an image.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional example, an image is affected by a subtle change in the amount of dampening water, and it is extremely difficult to adjust the amount of dampening water supplied. That is, if the dampening water is too much, the ink on the fixed toner image and the dampening water are likely to come into contact with each other, the density of the transferred image is lowered due to the emulsification of the ink, and the dampening water is too small. There was a problem that the soiling could not be prevented sufficiently.

Further, when the humidity in the apparatus is increased by using the dampening water, there is a problem that the electrophotographic characteristics are adversely affected, the toner image becomes unclear, and the image quality of the transferred image deteriorates.

Therefore, the present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to make it possible to recycle and reuse the plate, and An object of the present invention is to provide an image forming apparatus capable of stably forming a high-quality image with less fog.

(Means for Solving the Problems) In order to achieve the above-mentioned object, an image forming apparatus according to the present invention includes a photoconductor mounted in the main body of the device and an optical image projected on the photoconductor. A toner image forming unit that forms a corresponding toner image, a fixing unit that fixes the formed toner image on the photoconductor, a coloring material applying unit that applies a coloring material onto the fixed toner image, and the toner image. An image forming apparatus having a transfer means for transferring the above coloring material to a transfer material by contact transfer, wherein a toner image is formed on the photoreceptor.
A coating means for coating the surface of the photoconductor with a resin-made protective material for preventing the coloring material from adhering to the surface of the photoconductor, and a removing means for removing the resin-made protective material and the fixed toner coated on the surface of the photoconductor. It is composed by having.

(Operation) In the present invention having the above configuration, since the resin-made preventive material for preventing the adhesion of the coloring material is applied onto the photoconductor by the applying means before the toner image is formed on the photoconductor, There is no background fog due to the coloring material, and further deterioration of the image quality of the formed image due to emulsification of the coloring material and increase in humidity is prevented.
Further, since the removing member removes the resin preventive material and the fixing toner applied to the surface of the photoconductor, it is possible to continuously form new images while the photoconductor is mounted inside the apparatus main body. Can be reused.

(Example) Below, this invention is demonstrated based on the Example shown in figure.

FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus according to the present invention. In FIG. 1, 1 is a photosensitive drum that rotates in the direction of arrow A, and 2 is disposed near the photosensitive drum 1. Means for applying a coloring material (ink) adhesion preventing material, 3 a toner image forming portion including a primary charging device, an image exposing portion, a developing device and the like (not shown), 4 a heating member for heating and fixing the toner image, 5
Is an ink application means for applying ink onto the fixed toner image, 6 is a transfer roller as a transfer means which is pressed against the photosensitive drum 1 and is driven to rotate, 7 is a cleaner, 8 is a transfer material, 9 is a resist roller, 10 is a fixing device.

In this embodiment having the above structure, image formation is performed as follows. That is, first, a liquid ink adhesion preventing material (made of a material that repels ink) made of a synthetic resin is applied to the rotating photosensitive drum 1 substantially uniformly by an applying means 2 such as a sprayer. At this time, the photosensitive drum 1 moves in the direction of arrow B and is not in contact with the transfer roll 6. Next, the photosensitive drum 1 moves in the direction of the arrow C to come into pressure contact with the transfer roller 6 to follow the transfer roller 6, and
The area where the ink adhesion preventing material is applied reaches the toner image forming unit 3. Here, the photosensitive drum 1 is subjected to uniform charging, image exposure by an optical system, and toner image formation in this order, and then this toner image is heated by a heating body 4 such as an infrared lamp as fixing means to be photosensitive drum. A fixed toner image (printing plate) is fixed on the surface of No. 1. Then, ink is applied onto the fixed toner image by the ink applying means 5.

On the other hand, the movement of the ink image position formed on the fixed toner image on the photoconductor drum 1 (rotation of the photoconductor drum 1)
At the same time, the transfer material 8 is sent from the paper feed table through the registration roller 9. Then, in the nip portion N where the photosensitive drum 1 is in pressure contact with the transfer roller 6, the transfer material 8 comes into contact with the ink image and transfers the ink image onto the transfer material 8. After that, the fixing device 10 fixes the ink image, and the transfer material 8 is discharged.

By rotating the photosensitive drum 1 as described above, the image formation for transferring the ink image is repeated, and after the transfer of the required number of sheets is completed, the unnecessary fixed toner image (printing plate) and the ink adhesion preventing material are removed. It is scraped off from the photosensitive drum 1 by the blade of the cleaner 7 as a means to prepare for the next image formation. However, the cleaner 7 is in a non-contact state with the photosensitive drum 1 during the image formation, and is movable so as to be in the contact state during the cleaning. Further, as a cleaning method, in addition to scraping with the above blade, a method of conveying a removal material such as heated paper to melt and remove the prevention material and toner, or a method of removing with a web impregnated with a solvent, etc. There is.

Further, the surface of the photosensitive drum 1 is composed of a photoconductive substrate, and a material having excellent durability is suitable as this material, and particularly, an amorphous silicone photoconductive material is formed on a hard substrate such as metal or glass. Forming a sexual tank (Japanese Patent Laid-Open No. 54-86341)
(Disclosed in Japanese Patent Publication) is suitable.

Further, the above ink adhesion preventive agent acts as a proxy for the stain prevention of the image back shadow part, which was conventionally performed with dampening water, and the material is a resin such as a silicone resin or a fluorine compound whose coating surface energy is 25 dyn · cm ⁻¹ or less. Is used. If the surface energy exceeds 25 dyn · cm ⁻¹ , the ink repulsion property is lowered, which is not preferable.

Furthermore, the coating thickness of the ink adhesion prevention material is 0.1μm-5.0μ
m is preferable, and if it is less than 0.1 μm, it is difficult to obtain sufficient ink repellency, while if it exceeds 5.0 μm, the deterioration of electrophotographic properties becomes remarkable.

As described above, in the present embodiment, the ink adhesion preventing material made of resin is uniformly applied to the surface of the photosensitive drum 1 in advance before the formation of the fixed toner image by electrophotographic printing.
Since the ink is prevented from adhering to the non-image portion where the toner image is not formed, the background fog does not occur in the image formed on the transfer material. Further, unlike the conventional case, since fountain solution for preventing the non-image area from being stained with ink is not used, the ink is not emulsified with water and the image density is not lowered. Furthermore, as the humidity inside the device does not affect the electrophotographic characteristics, a clear toner image can be obtained.
As a result, a high quality image can be obtained.

Further, since the removing means removes the resin preventive material and the fixed toner applied to the surface of the photosensitive drum 1,
It is possible to continuously perform a series of processes such as applying a new resin preventive material to the surface of the photoconductor drum 1 again to form a toner image, and reuse the photoconductor drum 1 as a plate. Of course, it is possible to quickly form a new image.

In the above embodiment, the ink adhesion preventing material is applied before the uniform charging when forming the toner image. However, since this preventing material does not affect the charging state of the photosensitive drum 1, uniform charging and light irradiation are performed. It may be applied afterward, that is, before the toner image is formed.

Further, in the above-mentioned embodiments, the case where a liquid material is used as the coloring material and the preventing material has been described, but a fine powdery coloring material or the preventing material may be used.

 Next, a specific example of this embodiment will be described.

As the above specific example, after changing various conditions such as the type of ink adhesion preventing material (liquid) and the toner particle size, the plate making and printing were actually repeated, and the degree of stain on the non-image area and the image resolution were visually checked. A confirmatory test was performed. Here, as the implementation conditions of the above specific examples, there are 3 examples of the present invention and 2 examples of comparative examples. The conditions are shown below, and the results thereof are shown in the table.

[Example] As a photoreceptor, an amorphous silicon hydride thin film deposited to a thickness of 20 μm on the surface of an aluminum cylinder was used, and a fluorine-based polymer coating (FC-721) was used as an ink adhesion preventing liquid.
Was applied to obtain a coating film thickness of about 10 μm.

Original produced gives a potential of -430V by corona application charge of -6KV the photosensitive member, the exposure light illuminance 20l _ux and 0.2sec irradiation, the volume average particle diameter 4.4 mainly composed of styrene-acrylic resin and carbon black A magnetic brush was developed with a developer prepared by mixing a toner of μm (measured with a Coulter Counter using a 100 μm aperture) and a carrier, and then fixed by an infrared lamp to form.

Printing is performed by applying black ink (Aqualess G Sumi PLK manufactured by Toyo Ink Co., Ltd.) on the toner image with a rotating roller, and transferring the ink image onto a transfer paper. This is repeated 100 times, and the non-image area is printed. And the image resolution was confirmed.

Next, the toner image and the ink adhesion preventing liquid film were peeled off with a phosphor bronze leaf spring, one cycle was completed, and the steps after the application of the ink adhesion preventing liquid were repeated again.

[Example] As the ink adhesion preventing liquid, the fluorine-based paint Morse Vat MR-S20 (manufactured by Asahi Glass Co., Ltd.) was used, and the other conditions were the same as those in the above-mentioned example.

[Example] A toner having a volume average particle diameter of 12.1 μm was used as the toner, and the other conditions were the same as those of the above-described example.

[Comparative Example] The same as the above example except that the ink adhesion preventing liquid was not applied.

Comparative Example The same as the above example except that a selenium photoconductor was used as the photoconductor and no ink adhesion preventing liquid was applied.

As can be seen from the table above, when the ink adhesion preventive material is not applied, the ink adheres to the non-toner area and the printed image cannot be identified, or when the selenium photoconductor is used, the toner image is peeled off by the leaf spring. It was found that the surface was scratched during the removal. Therefore, it can be said that a photosensitive member using amorphous silicon is excellent in abrasion resistance. In addition, as an ink adhesion prevention material, the above FC-721, MR-
It was found that both S20 were effective and did not adversely affect the formed image.

(Effects of the Invention) The present invention has the above-mentioned constitutions and operations, and by applying a resin-made preventive agent for preventing the adhesion of the coloring agent on the photoconductor, the background fog can be prevented and the ink density can be reduced. Since it is possible to prevent deterioration of image quality due to deterioration or change in electrophotographic characteristics, it is possible to obtain an extremely high quality image, and the removing means removes the resin-made preventive material and the fixed toner applied to the surface of the photoconductor. Therefore, the photoconductor can be reused as a plate for continuously forming new images in the state where it is mounted in the apparatus main body, and has an effect that new images can be formed quickly.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum, 2 ... Coating means 3 ... Toner image forming section, 4 ... Heating body 5 ... Ink applying means, 6 ... Transfer roller 8 ... Transfer material

Front page continuation (72) Inventor Masa Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-55-135861 (JP, A) JP-A-48-19305 ( JP, A) JP-A-57-94756 (JP, A)

Claims (2)

[Claims] 1. A photoconductor mounted in the main body of the apparatus,
A toner image forming unit that forms a toner image corresponding to the optical image projected on the photoconductor, a fixing unit that fixes the formed toner image on the photoconductor, and a coloring material is provided on the fixed toner image. An image forming apparatus comprising: a coloring material applying unit for performing a contact transfer of the coloring material on the toner image to a transfer material, wherein the coloring material of the coloring material is formed before the toner image is formed on the photoreceptor. A coating means for coating the surface of the photoconductor with a resin-made preventive material for preventing adhesion to the surface of the photoconductor, and a removing means for removing the resin-made preventive material and the fixed toner applied on the surface of the photoconductor An image forming apparatus characterized by the above. 2. The image forming apparatus according to claim 1, wherein the photoconductor contains amorphous silicone as a main component.