JP2008158357A - Electrophotographic type image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic type image forming apparatus which can deal with a large size and with which a high gloss image of a photographic tone can be obtained with a simple configuration. <P>SOLUTION: The electrophotographic type image forming apparatus uses a recording medium having a transparent portion in at least a part through which paper can pass in order to form an image. The apparatus includes a UV curing ink applying means 15 which applies a non-transparent UV curing ink to at least an image forming region from above an image forming surface during a series of working operations after forming and fixing the image by an electrophotographic system on the recording medium. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus that uses a recording medium having a transparent portion at least part of which can be passed to form an image and obtains a glossy photographic image.

Conventionally, in an electrophotographic image forming apparatus, various attempts have been made to obtain a glossy photographic image (see, for example, Patent Documents 1 to 5).
For example, Patent Document 1 uses a special toner for producing gloss. After normal image formation on a sheet, before reaching the fixing unit, a transparent toner is uniformly formed on the entire surface and fixed to obtain a photographic image quality.
Further, in attempts such as Patent Document 2, a special recording medium is used to obtain gloss. It is said that a uniform gloss on the surface can be realized by providing a thermoplastic resin layer on the front and back of the paper and further applying pressure and heat after fixing the image normally.

Further, in Patent Document 3, a special fixing device is used to obtain gloss. After normal fixing (first fixing), a second fixing unit composed of a belt having high smoothness is provided, and the toner is melted again, followed by cooling and peeling, and using the smoothness of the belt, uniform gloss is obtained. You can get.
In Patent Document 4, a pressure-sensitive adhesive layer is formed on a transparent film, and the transparent film is adhered to the image surface (printing surface). Therefore, the adhesion between the image and the transparent film is poor, and the photographic image quality cannot be reproduced.
Further, Patent Document 5 is an image display plate using a light retroreflective sheet material, and it is difficult to print on the light retroreflective sheet material. It is not an attempt to pursue tonal image quality.
JP 2002-341623 A JP 2004-191678 A JP 2003-270991 A Japanese Patent Laid-Open No. 10-278183 JP 2004-302044 A

However, the technique of Patent Document 1 has problems such as always supplying uniform transparent toner to the entire surface and a high load on the fixing unit due to the difference in toner thickness between the image area and the non-image area.
Further, in order to obtain a predetermined effect using the technique of Patent Document 2, it is necessary to use a special fixing device shown in Patent Document 3 in combination, and there are problems in terms of configuration, cost, power consumption, and the like.
Therefore, in the prior art, in order to obtain a high-gloss image such as a photograph, there is a time required for cooling by passing through a special material recording medium or a special fixing device after fixing of normal image formation. Therefore, not only is productivity lowered, but it is difficult to cope with large sizes.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electrophotographic image forming apparatus capable of obtaining a photo-like high-gloss image capable of handling a large size with a simple configuration in consideration of the above situation. It is in.

In order to solve the above-mentioned problem, the invention according to claim 1 is an electrophotographic image forming apparatus using a recording medium having a transparent portion at least partially capable of passing paper for forming an image. Ultraviolet curable ink application means for applying non-transparent ultraviolet curable ink on at least the image forming area from above the image forming surface during a series of work operations after forming and fixing an image on a recording medium by electrophotography And an electrophotographic image forming apparatus.
According to a second aspect of the present invention, in the recording medium, the electrophotographic image forming apparatus according to the first aspect is characterized in that at least an image forming surface of the transparent portion is smooth.
According to a third aspect of the present invention, there is provided the electrophotographic image forming apparatus according to the first or second aspect, wherein the non-transparent ultraviolet curable ink is white after ultraviolet curing.
According to a fourth aspect of the present invention, there is provided the electrophotographic image forming apparatus according to any one of the first to third aspects, wherein a mirror image is formed by inverting the original image on the recording medium. To do.

Further, in the invention described in claim 5, the ultraviolet curable ink applying means for applying the non-transparent ultraviolet curable ink on the recording medium after the electrophotographic image formation and fixing has a large number of application openings in a straight line. 4. The electrophotographic image forming apparatus according to claim 1, wherein the electrophotographic image forming apparatus is a so-called line head coating means arranged in a line.
According to a sixth aspect of the present invention, there is provided an electrophotographic image forming apparatus according to the fifth aspect, further comprising a control unit that changes a width of the coating region in accordance with the size of the recording medium.
According to a seventh aspect of the present invention, there is provided the electrophotographic apparatus according to any one of the first to third aspects, wherein an ultraviolet irradiation device that irradiates the recording medium with ultraviolet rays after the ultraviolet curable ink is applied. The image forming apparatus is characterized.

  According to the present invention, an image is formed on a transparent recording medium, a non-transparent white UV (ultraviolet) curable ink is applied to the surface on which the image is formed, and UV (ultraviolet) is irradiated after application. By this, it is possible to obtain an image of a photographic tone that is immediately dried, has good storage stability, and can be obtained. A photographic image can be easily obtained by an electrophotographic image forming apparatus that performs these operations in a series of operations.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus according to the present invention. FIG. 2 is a schematic view showing an example of a recording medium in which at least one part is transparent.
Referring to FIG. 1, the image forming apparatus 20 includes four image forming units 1Y, 1M, 1C, for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). It has 1K. The color order of Y, M, C, and K is not limited to that shown in FIG.
Each of the image forming units 1Y, 1M, 1C, and 1K includes photosensitive drums 11Y, 11M, 11C, and 11K as image carriers, and a charging unit, a developing unit, and a cleaning unit.
The image forming units 1Y, 1M, 1C, and 1K are arranged so that the rotation axes of the photosensitive drums 11Y, 11M, 11C, and 11K are parallel to each other and arranged at a predetermined pitch in the transfer sheet moving direction. Is set.

Above the image forming units 1Y, 1M, 1C, and 1K, a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like are provided. An optical writing unit 3 for irradiating while scanning with laser light is disposed.
Below the image forming units 1Y, 1M, 1C, and 1K, a belt drive having a transfer conveyance belt 60 that carries transfer paper and conveys it so as to pass through the transfer portions of the image forming units 1Y, 1M, 1C, and 1K. A transfer unit 6 as an apparatus is arranged.
A cleaning device 85 including a brush roller and a cleaning blade is disposed on the outer peripheral surface of the transfer conveyance belt 60 so as to come into contact therewith. The cleaning device 85 removes foreign matters such as toner adhering to the transfer conveyance belt 60.

On the side of the transfer unit 6, a belt fixing type fixing unit 7, a paper discharge tray 8, and the like are provided. Under the image forming apparatus, paper feed cassettes 4a and 4b on which transfer paper 100 is placed are provided. A manual tray MF that manually feeds paper from the side of the image forming apparatus is also provided.
In addition, a toner replenishing container TC is provided, and a waste toner bottle, a duplex / reversing unit, a power supply unit, and the like (not shown) are also provided in a space S indicated by a one-dot chain line.
The developing devices 10Y, 10M, 10C, and 10K as the developing means have the same configuration, and are the two-component developing type developing devices 10Y, 10M, 10C, and 10K that differ only in the color of the toner used. A developer composed of toner and a magnetic carrier is contained.
The developing devices 10Y, 10M, 10C, and 10K include a developing roller facing each of the photosensitive drums 11Y, 11M, 11C, and 11K, a screw that conveys and stirs the developer, a toner concentration sensor, and the like.

Although not shown, the developing roller includes an outer rotatable sleeve and a magnet fixed on the inner side. In accordance with the output of the toner density sensor, toner is supplied from the toner supply device.
First, a predetermined voltage is applied to the charging roller from a power source (not shown) to charge the surfaces of the opposing photosensitive drums 11Y, 11M, 11C, and 11K. The surface of the photosensitive drums 11Y, 11M, 11C, and 11K charged to a predetermined potential is subsequently scanned with laser light based on image data by the optical writing unit 3, and an electrostatic latent image is written.
When the surface of each of the photosensitive drums 11Y, 11M, 11C, and 11K carrying the electrostatic latent image reaches the developing devices 10Y, 10M, 10C, and 10K, a developing roller that is disposed to face the photosensitive drums 11Y, 11M, 11C, and 11K. As a result, toner is supplied to the electrostatic latent images on the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K to form toner images.
The above operation is similarly performed on the photosensitive units 2Y, 2M, 2C, and 2K at predetermined timings, and toner images of predetermined colors are formed on the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K, respectively. The

The transfer paper 100 is transported from any of the paper feed cassettes 4 a and 4 b or the manual feed tray MF, and once stops when it reaches the registration roller 5. Thereafter, the transfer paper 100 is sent out from the registration roller 5 in synchronization with the above-described image forming operations of the photoconductor units 2Y, 2M, 2C, and 2K.
The toner images on the photosensitive drums 11Y, 11M, 11C, and 11K are sequentially transferred onto the transfer paper 100 while being conveyed by the transfer conveyance belt 60. A voltage is applied from a power source (not shown) to the primary transfer rollers 67Y, 67M, 67C, and 67K that are disposed to face the photosensitive drums 11Y, 11M, 11C, and 11K with the transfer and conveyance belt 60 interposed therebetween.
As a result, the toner image is transferred onto the transfer paper 100, and the voltage to the primary transfer rollers 67Y, 67M, 67C, and 67K is opposite to the polarity of the toner on the photosensitive drums 11Y, 11M, 11C, and 11K. Is applied.
Then, the transfer paper 100 that has passed through the position facing the photosensitive drum 11K and on which the four color toner images are superimposed is subsequently conveyed to the fixing unit 7, where the image is fixed by receiving heat and pressure.
The transfer paper (recording medium) 100 used here is a recording medium having a partially transparent portion. Such a recording medium may have a shape in which a certain part is transparent, half may be transparent and half may be non-transparent, or all may be transparent.

As shown in FIG. 2, in FIG. 2A, the transfer paper (recording medium) 100 has a case where more than half of the recording medium is a non-transparent portion 100a and the rest is a transparent portion 100b in the transport direction. Show. FIG. 2B shows a case where all are transparent portions 100b.
FIG. 2C shows a case where the entire half in the longitudinal direction of the recording medium is the non-transparent portion 100a and the other half is the transparent portion 100b. FIG. 2D shows a case where only the upper end is the non-transparent portion 100a and the rest is the transparent portion 100b in the conveyance direction of the recording medium 100.
By applying non-transparent UV curable ink to the image forming surface side of the recording medium 100 after the image is formed on the transparent portion 100b and passed through the fixing unit 7 that fixes the image by heating and pressing. In addition, it is possible to obtain a photographic image using electrophotography.

FIG. 3 is a schematic view showing various application means for applying non-transparent UV curable ink on the image forming surface side of the recording medium on the same recording medium. FIG. 4 is a schematic view showing the ultraviolet irradiation means.
As the means for applying the non-transparent UV curable ink, a line head application means 15 as shown in FIG. 3 that can easily change the application area is desirable. However, any general method such as roller application means 16, spray application means 17, sponge application means, offset printing means, stencil printing means, intaglio printing means may be used.
The surface of at least the image forming surface of the transparent portion 100b of the recording medium 100 is smoothed, an image is formed on the smooth surface of the transparent recording medium 100, and a non-transparent liquid is applied to the surface on which the image is formed. To. As a result, when the image is viewed from the non-image surface of the transparent recording medium 100, the image is formed on the smooth surface. Obtainable. If the non-image forming surface is also smooth, a more glossy photographic image quality can be obtained.

For non-transparent UV curable inks, it is advantageous to use inks that are white after UV curing. By forming an image on the smooth surface of the transparent recording medium 100 and applying a white and non-transparent UV curable ink to the surface on which the image is formed, the image is formed on the transparent recording medium 100. A region that has not been formed becomes white when viewed from the non-image forming side, and a more photographic image can be obtained.
The original image is inverted on the recording medium 100 to form a mirror image. Thus, when the image is viewed from the non-image surface of the transparent recording medium 100, the original image is inverted to form a mirror image, so that a photographic image that is a normal image when viewed from the non-image surface side is obtained. It becomes possible.
In electrophotography, images are generally formed on a plurality of types of media having different recording medium (paper) widths, from a small size to a large size. It is desirable that the non-transparent UV curable ink application means for obtaining a photographic tone can be easily switched to a different width.

The above-described line head coating means 15 in which a large number of coating ports are arranged in a straight line is used for coating non-transparent UV curable ink after electrophotographic image formation and fixing. The line head coating unit 15 can easily switch the coating width. By combining the coating unit and the electrophotographic image forming apparatus 20, the configuration of the apparatus can be changed even for recording media having different widths. A photographic image can be obtained.
For this reason, although not shown in the figure, a control means is provided for changing the width of the application region in accordance with the size of the recording medium 100. Accordingly, the control unit can arbitrarily change the width of the application region based on the information in the width direction of the recording medium 100, so that application to unnecessary portions can be minimized.
Any non-transparent UV curable ink may be used as long as it is suitable for application to the recording medium 100 having the transparent portion 100b. As for the color, white is desirable as the most general photograph, but other colors may be used.

As shown in FIG. 4, the image forming apparatus 20 is provided with an ultraviolet irradiation device 18 for irradiating the recording medium 100 with ultraviolet rays after the UV curable ink is applied. As described above, since the ultraviolet rays are irradiated after the application of the UV curable ink, the image discharged from is immediately dried, and can correspond to high-speed printing, large-size printing, and the like.
FIG. 5 is a schematic view showing an embodiment of an image forming apparatus provided with UV curable ink application means and an ultraviolet irradiation device. In FIG. 5, the image forming apparatus 20 has a UV curable ink application unit 15 using a line head and an ultraviolet irradiation device 18 using an ultraviolet lamp at the upper left part.
According to this embodiment, the application area of the UV curable ink can be changed to an arbitrary size corresponding to the recording medium width (in the depth direction in FIG. 5) by a control means (not shown). In FIG. 5, the other configuration is the same as that of the image forming apparatus 20 of FIG.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to the present invention. It is the schematic which shows the example of a recording medium with at least one part transparent. It is the schematic which shows the various application | coating means which apply | coats non-transparent UV curable ink on the image formation surface side of a recording medium on the same recording medium. It is the schematic which shows an ultraviolet irradiation means. It is the schematic which shows embodiment of the image forming apparatus provided with UV curable ink application means and an ultraviolet irradiation device.

Explanation of symbols

1Y Image forming unit 6 Transfer unit 7 Fixing unit 10Y Developing device 11Y Photosensitive drum (image carrier)
15 UV curable ink application means (application means by line head)
18 Ultraviolet irradiation device 20 Electrophotographic image forming apparatus 100 Recording medium (transfer paper, paper)
100a Non-transparent part 100b Transparent part

Claims (7)

  In an electrophotographic image forming apparatus that uses a recording medium having a transparent portion at least part of which can be passed to form an image, an image is formed on the recording medium by an electrophotographic method and fixed. An electrophotographic image forming apparatus comprising: an ultraviolet curable ink application unit that applies non-transparent ultraviolet curable ink to at least an image forming region from above an image forming surface during a work operation.   2. The electrophotographic image forming apparatus according to claim 1, wherein at least the surface of the image forming surface of the transparent portion is smooth on the recording medium.   3. The electrophotographic image forming apparatus according to claim 1, wherein the non-transparent ultraviolet curable ink is white after ultraviolet curing.   4. The electrophotographic image forming apparatus according to claim 1, wherein a mirror image is formed by inverting the original image on the recording medium.   After the electrophotographic image formation and fixing, the ultraviolet curable ink application means for applying the non-transparent ultraviolet curable ink on the recording medium is applied by a so-called line head in which a large number of application ports are arranged in a straight line. 4. The electrophotographic image forming apparatus according to claim 1, wherein the electrophotographic image forming apparatus is a means.   6. The electrophotographic image forming apparatus according to claim 5, further comprising a control unit that changes a width of the coating area in accordance with a size of the recording medium.   4. The electrophotographic image forming apparatus according to claim 1, wherein an ultraviolet irradiation device for irradiating the recording medium with ultraviolet rays is disposed after the application of the ultraviolet curable ink.

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