KR20070010799A - Electrophotographic image forming apparatus for printing photographic image and method for printing photographic image using the same - Google Patents

Abstract

An electrophotographic image forming apparatus for printing photographic images and a photographic image printing method using the apparatus are provided to print a glossy image in a non-image region as well as an image region of a printing medium. An electrophotographic image forming apparatus includes a photosensitive medium(115), color developers(121C,121M,121Y,121K), a transparent developer(121TR), and an intermediate transfer medium(117). Electrostatic latent images for a color image and a transparent image is formed by exposure on the surface of the photosensitive medium. The color developers contain a color glossy toner charged with one polarity and provide the color glossy toner to the electrostatic latent image for the color image to develop the color image on the surface of the photosensitive medium. The transparent developer contains a transparent glossy toner charged with a polarity different from the polarity of the color glossy toner and supplies the transparent glossy toner to a region surrounding the electrostatic latent image for the transparent image to develop the transparent image on the surface of the photosensitive medium. The color image and the transparent image are sequentially transferred to the intermediate transfer medium.

Description

Electrophotographic image forming apparatus for printing photographic image and method for printing photographic image using the same}

1 is a cross-sectional view showing an electrophotographic image forming apparatus according to a first embodiment of the present invention.

2 is a cross-sectional view of an electrophotographic image forming apparatus according to a second exemplary embodiment of the present invention.

3 is a cross-sectional view of an electrophotographic image forming apparatus according to a third exemplary embodiment of the present invention.

4 is a plan view illustrating an example of a print medium on which an image printed by the electrophotographic image forming apparatus of the present invention is displayed.

5 is a partially enlarged cross-sectional view of the print medium of FIG. 4.

<Description of Symbols for Main Parts of Drawings>

100 ... Electrophotographic image forming apparatus 102 ... Feed cassette

105 ... pickup roller 108 ... transfer roller

110 ... fixing unit 115 ... photosensitive media

117 Intermediate transfer medium 120 Turret

121 ... developing 123 ... developing roller

125 ... toner charger 126 ... corona wire

130 ... Optical syringes 132, 134 ... Waste toner cleaner

The present invention relates to an electrophotographic image forming apparatus, and more particularly, to an electrophotographic image forming apparatus capable of printing photographic images.

In general, an electrophotographic image forming apparatus is configured to form an electrostatic latent image by scanning a light beam on a surface of a photosensitive medium charged at a constant potential, and developing the electrostatic latent image with a toner, which is a developer, and transferring the same to a print medium. The apparatus refers to a device for fixing a single color image or a color image.

The photographic image developed on the photo paper is different from the conventional printing image in that it is glossy. In order to achieve such a gloss effect with an electrophotographic image forming apparatus, a so-called glossy toner with a gloss should be used as a developer. However, the gloss toner is also distributed only in the image area where an image is formed on the print medium, but not in the non-image area without an image, so that a difference in glossiness occurs between the image area and the non-image area. Due to such a limitation, the photographic image printed by the conventional electrophotographic image forming apparatus is insufficient to give a feeling of a photograph developed on photo paper.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an electrophotographic image forming apparatus for printing a photo image capable of printing a glossy image in a non-image region as well as an image region of a print medium, and a photo image printing method using the same It is technical problem to provide.

In addition, the present invention provides an electrophotographic image forming apparatus for photographic image printing and a photographic image printing using the same, capable of printing an image in which the toner thickness distributed in the image area and the non-image area of the print medium is uniform and there is no difference in glossiness. It is a technical task to provide a method.

In order to achieve the above technical problem, the present invention provides a photosensitive medium having a color image and a transparent image electrostatic latent image formed on the surface by exposure to light; A color developer which is charged with one polarity and contains a colored glossy toner, and supplies the color gloss toner to the color image electrostatic latent image to develop a color image on the surface of the photosensitive medium; A transparent image on the surface of the photosensitive medium by supplying the transparent glossy toner to the outer region of the electrostatic latent image for the transparent image, and containing a transparent glossy toner charged with a polarity different from that of the color glossy toner. A transparent developing device for developing the film; And an intermediate transfer medium on which the color image and the transparent image are sequentially transferred.

Preferably, the electrophotographic image forming apparatus may be configured to be transferred onto an intermediate transfer medium so that the color image and the transparent image do not overlap.

Preferably, the electrophotographic image forming apparatus may further include a toner charger which charges the transparent gloss toner developed as a transparent image on the surface of the photosensitive medium with the same polarity as the color gloss toner.

Preferably, the toner charger may be a corotron charger that includes a corona wire to charge the transparent gloss toner in a non-contact state.

Preferably, the color developing device is provided with a plurality of colors containing glossy toners of different colors so as to print a multicolor image composed of a plurality of colors, and a plurality of different color images and transparent on the surface of the photosensitive medium. The images are sequentially developed, and the transparent electrostatic latent image may be formed on the surface of the photosensitive medium by exposure of an entire image region in which the plurality of different color image electrostatic latent images are combined.

Preferably, the plurality of color developers include a cyan developer containing cyan color gloss toner, a magenta developer containing magenta color gloss toner, and a yellow color gloss toner. And a black developer containing a black (K) black color glossy toner.

Preferably, the plurality of color developing devices and the transparent developing device are mounted on a rotating turret, and each developing device sequentially faces the photosensitive medium to supply toner to the photosensitive medium by rotating the turret. have.

Preferably, the plurality of color developing devices and the transparent developing devices may be arranged to be stacked around the photosensitive medium, and each developer may be configured to sequentially approach the photosensitive medium to supply toner to the photosensitive medium.

Preferably, the transparent gloss toner is developed into a transparent image in a state of being charged with a positive polarity, and the color gloss toner is developed into a color image in a state of being charged with a negative polarity.

In addition, the present invention includes a color glossy toner, which is charged with one polarity, contains colored glossy toner, and the color gloss toner is supplied to a color electrostatic latent image formed by exposure to color on the surface. A color developing device equipped with a photosensitive medium on which an image is developed; It is charged with a polarity different from that of the color gloss toner and contains a transparent glossy toner, and the transparent gloss toner is supplied to an outer region of a transparent image electrostatic latent image formed by exposure, so that a transparent image is formed on the surface. A transparent developer equipped with the photosensitive medium to be developed; And a transfer machine for transferring the color image and the transparent image onto a print medium.

Preferably, the electrophotographic image forming apparatus may be configured to be transferred to a transfer machine so that the color image and the transparent image do not overlap.

Preferably, the electrophotographic image forming apparatus may further include a toner charger which charges the transparent gloss toner developed as a transparent image on the surface of the photosensitive medium of the transparent developer with the same polarity as the color gloss toner.

Preferably, the toner charger may be a corotron charger that includes a corona wire to charge the transparent gloss toner in a non-contact state.

Preferably, the color developing apparatus includes a plurality of color toners containing different color gloss toners, each of which is equipped with a photosensitive medium, so as to print a multicolor image composed of a plurality of colors, and the photosensitive medium of the plurality of color developing devices. A plurality of different color images are developed on the surface, and a transparent image is developed on the surface of the photosensitive medium of the transparent developer, and the electrostatic latent image for the transparent image is formed of the entire image region in which the plurality of different color image electrostatic latent images are combined. It may be formed on the surface of the photosensitive medium by exposure.

Preferably, the plurality of color developers include a cyan developer containing cyan color gloss toner, a magenta developer containing magenta color gloss toner, and a yellow color gloss toner. And a black developer containing a black (K) black color glossy toner.

Preferably, the transparent gloss toner is developed into a transparent image in a state of being charged with a positive polarity, and the color gloss toner is developed into a color image in a state of being charged with a negative polarity.

In addition, the present invention is a color exposure step of forming a color image electrostatic latent image corresponding to a color image on the surface of the photosensitive medium by exposure to light; A color image developing step of developing a color image by supplying a color glossy toner, which is charged with one polarity, to the color image electrostatic latent image; A color image intermediate transfer step of transferring the color image to an intermediate liver transfer medium; Forming a transparent electrostatic latent image for forming a transparent image on the surface of the photosensitive medium by exposure; A transparent image developing step of developing a transparent image by supplying a transparent glossy toner that is charged with a different polarity from the color gloss toner to an outer region of the electrostatic latent image for the transparent image; A transparent image intermediate transfer step of transferring the transparent image to an intermediate transfer medium; And a sinus transfer step of transferring the color image and the transparent image transferred to the intermediate transfer medium to a print medium together.

Preferably, in the intermediate transfer step, the color image and the transparent image may be transferred onto the intermediate transfer medium so as not to overlap.

Preferably, the photographic image printing method may further include a transparent image charging step of charging the transparent gloss toner developed as a transparent image on the surface of the photosensitive medium with the same polarity as the color gloss toner.

Preferably, the color exposing step, the color image developing step, and the color image intermediate transfer step are performed on the gloss toners of different colors to form a cycle, such that a plurality of different color images are combined on the intermediate transfer medium. In the transparent exposure step, an electrostatic latent image for transparent images may be formed on the surface of the photosensitive medium by exposure of an entire image area in which a plurality of different color image electrostatic latent images are combined.

Preferably, the different color gloss toners include cyan color gloss toner, magenta color gloss toner, yellow color gloss toner, and black (K) black. It can be made of color gloss toner.

Preferably, the color gloss toner of the color image development step may be charged with a negative polarity, and the transparent gloss toner of the color image development step may be charged with a positive polarity.

In addition, the present invention is a color exposure step of forming a color image electrostatic latent image corresponding to a color image on the surface of the photosensitive medium by exposure to light; A color image developing step of developing a color image by supplying a color glossy toner, which is charged with one polarity, to the color image electrostatic latent image; Forming a transparent electrostatic latent image on the surface of the photosensitive medium by exposure; A transparent image developing step of developing a transparent image by supplying a transparent glossy toner that is charged with a different polarity from the color gloss toner to an outer region of the electrostatic latent image for the transparent image; And a transfer step of transferring the color image and the transparent image onto a print medium.

Preferably, the photographic image printing method may further include a transparent image charging step of charging the transparent gloss toner developed as a transparent image on the surface of the photosensitive medium with the same polarity as the color gloss toner.

Preferably, in the transfer step, the color image and the transparent image may be transferred onto the print medium so as not to overlap.

Preferably, the color exposure step and the color image development step are performed on the glossy toners of different colors to develop a plurality of different color images on a plurality of photosensitive media, and the plurality of different color images in the transparent exposure step. The electrostatic latent image for the transparent image may be formed on the surface of the photosensitive medium by exposure of the entire image region in which the electrostatic latent images are combined.

Preferably, the different color gloss toners include cyan color gloss toner, magenta color gloss toner, yellow color gloss toner, and black (K) black. It can be made of color gloss toner.

Preferably, the color gloss toner of the color image development step may be charged with a negative polarity, and the transparent gloss toner of the color image development step may be charged with a positive polarity.

Hereinafter, an electrophotographic image forming apparatus for photographic image printing and a photographic image printing method using the same will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing an electrophotographic image forming apparatus according to a first embodiment of the present invention.

Referring to FIG. 1, the electrophotographic image forming apparatus 100 according to the first exemplary embodiment of the present invention has a multi-path in which an image is transferred to a printing medium P via an intermediate transfer medium 117. The image forming apparatus is a turret (120) equipped with five developing devices (121) inside the case 101, a cylindrical photosensitive medium 115, a optical scanner 130, an intermediate transfer medium 117 And a transfer roller 108.

The photosensitive medium 115 has a photosensitive layer made of a photoconductive material formed on the outer circumferential surface of a metal drum by a method such as vapor deposition. The optical scanner 130 is installed below the photosensitive medium 115 and scans a light beam corresponding to image information to the photosensitive medium 115. An electrostatic latent image is formed on the surface of the photosensitive medium 115 exposed by the light beam. In general, the laser scanning unit 130 employs a laser scanning unit (LSU) using a laser diode as a light source.

The five developing devices 121C, 121M, 121Y, 121K, and 121TR mounted on the turret 120 are cyan (C), magenta (M), yellow (Y), black (K) color, and colorless transparent solid powder phases, respectively. Is holding toner. In order to take advantage of the glossiness of the photographic image, the toners employ a glossy gloss toner. Glossy toner can be made by adding wax in addition to colorants or other internal additives and external additives which are usually added to the binder resin. Specific examples of the wax may include natural wax, paraffin wax, ester wax, and the like. As the amount of the wax added increases, the glossiness of the toner increases and can be added up to about 5% of the total weight ratio of the toner. Preferably an amount of about 3% may be added.

The glossy toner contained in the transparent developer 121TR is colorless and transparent. Thus, unlike conventional toners, no colorant is added. Color gloss toners having a color in this embodiment are charged with negative polarity when they are accommodated in the corresponding color developing devices 121C, 121M, 121Y, 121K. However, the transparent gloss toner contained in the transparent developer 121TR is charged with a positive polarity at the time of receipt unlike the other toners. In order to have a positive polarity, a transparent gloss toner may be prepared by adding a wax having an acid value of 10 or less to a polyester resin binder resin having an acid value of 10 or less. The transparent gloss toner may be hydrophobized to add at least one of silica, silica titanium oxide, and aluminum oxide having a BET surface area of 150 m 2 / g or more as an external additive.

Four color developing devices 121C, 121M, 121Y, and 121K each develop a color image or a transparent image of each color by supplying toner contained therein to the photosensitive medium 115. The rollers 123C, 123M, 123Y, 123K and 123TR are respectively provided. The turret 120 rotates counterclockwise to sequentially face the developing devices 121C, 121M, 121Y, 121K, and 121TR to the photosensitive medium 115, and to face the photosensitive medium 115. 121M, 121Y, 121K, and 121TR supply toner to the photosensitive medium 115 to develop a color image or a transparent image.

Although not shown, a supply roller for supplying toner to the developing rollers 123C, 123M, 123Y, 123K, and 123TR in the developing units 121C, 121M, 121Y, 121K, and 121TR, and the developing rollers 123C, 123M, A doctor blade for regulating the amount of toner supplied to 123Y, 123K, and 123TR is provided, and an agitator for firmly shaking the toner is provided.

A toner charger 125 is arranged around the photosensitive medium 115 to charge the negatively-transparent toner, which is developed as a transparent image, on the outer circumferential surface of the photosensitive medium 115 to negative (-) polarity as the color gloss toner. The toner charger 125 includes a corona wire 126 extending in a lengthwise direction of the photosensitive medium 115 and a conductor 127 surrounding the corona wire 126. As a type of charger for charging the photosensitive medium 115 to a constant potential, it is known to those skilled in the art.

When a voltage is applied to the corona wire 126, gas molecules around the corona wire 126 are ionized, and the ions move toward the photosensitive medium 115 that is not covered by the conductor 127. The ions thus moved are adsorbed on the transparent gloss toner on the surface of the photosensitive medium 115, thereby charging the transparent gloss toner with negative polarity. The toner charger 125 charges the toner to a negative polarity without contacting the transparent gloss toner adhered to the surface of the photosensitive medium 115, and thus the transparent gloss toner charged to the negative polarity is Similar to the color gloss toner, it may be transferred to the intermediate transfer medium 117 and the print medium P. FIG. In a preferred embodiment, a voltage of 3 kV to 5 kV is applied to the corona wire 126.

The intermediate transfer medium 117 is a transfer belt for transferring a color image or a transparent image made of toner, and is circulated by being supported by a plurality of support rollers. A cyan (C) image, a magenta (M) image, a yellow (Y) image, a black (K) image, and a transparent image are sequentially transferred to the intermediate transfer medium 117 so that a multi-color image is obtained. Is formed. In the multicolor image, glossiness appears not only in an image region in which characters, symbols, patterns, etc. are expressed in a predetermined color, but also in a transparent non-image region. The length of the intermediate transfer medium 117 is equal to or longer than the length of the print medium P to which the multicolor image is finally transferred.

The transfer roller 108 is disposed to face the intermediate transfer medium 117. The transfer roller 108 is spaced apart from the intermediate transfer medium 117 while the toner is transferred to the intermediate transfer medium 117. When the toner image is completed on the intermediate transfer medium 117, the transfer medium 108 is printed. To contact the intermediate transfer medium 117 to transfer to.

The fixing unit 110 fixes the toner image transferred to the printing medium P on the printing medium P. FIG. The fixing unit 110 is configured to rotate a pair of rollers engaged with each other at a predetermined pressure, and includes a heating element (not shown) for heating the printing medium P. When the print medium P on which the toner image is transferred passes through the fixing unit 110, the toner image is fixed to the print medium P by heat and pressure, thereby completing printing of the image.

In the lower portion of the image forming apparatus 100, a paper feed cassette 102 on which a printing medium P is loaded is detachably inserted into the case 101, and a printing medium P loaded on the paper cassette 102 is mounted. Is picked up one by one from the one loaded on top by the pickup roller 105. The paper feed roller 106 feeds the print medium P picked up by the pickup roller 105 toward the transfer roller 108. Reference numeral 113 denotes a discharge roller for discharging the print medium P out of the case 101. An upper side of the case 101 is provided with a discharge stand 103 on which the print medium P discharged by the discharge roller 113 is loaded.

On the other hand, the image forming apparatus 100 is a first waste toner cleaner which scrapes and removes the waste toner remaining on the outer circumferential surface of the photosensitive medium 115 without being transferred to the intermediate transfer medium 117 from the photosensitive medium 115. 132 and a second waste toner cleaner 134 which scrapes off the waste toner remaining on the intermediate transfer medium 117 without being transferred to the print medium P from the intermediate transfer medium 117.

A method of printing a photographic image with an electrophotographic image forming apparatus 100 having such a configuration will be described.

First, when the turret 120 is rotated such that the cyan developer 121C faces the photosensitive medium 115, the optical scanning device 130 emits a light beam corresponding to the image information of cyan (C) color. ), Thereby forming an electrostatic latent image for cyan (C) image corresponding to an image of cyan (C) color on the surface of the photosensitive medium 115. Then, the negative polarity cyan (C) gloss toner contained in the cyan developer 121C is attached to this electrostatic latent image so that a toner image of glossy cyan (C) color is developed on the photosensitive medium 115, and this toner The image is transferred to the intermediate transfer medium 117.

When the toner image formation of the cyan (C) color is completed on the intermediate transfer medium 117, the turret 120 rotates 72 degrees counterclockwise so that the magenta developer 121M faces the photosensitive medium 115, A 130 scans a light beam corresponding to the image information of magenta (M) color onto the photosensitive medium 115 to form an electrostatic latent image for the magenta (M) image. Then, a negative polarity magenta (M) gloss toner contained in the magenta developer (121M) is attached to this electrostatic latent image, and a toner image of glossy magenta (M) color is developed on the photosensitive medium (115). The image is transferred to the intermediate transfer medium 117.

At this time, in consideration of the circulation speed of the intermediate transfer medium 117, the scan timing of the light beam scanned from the optical scanning machine 130 is appropriately set, and the cyan (C) color toner first formed on the intermediate transfer medium 117 is formed. The front end of the image and the front end of the toner image of magenta (M) color starting to be transferred from the photosensitive medium 115 to the intermediate transfer medium 117 are exactly matched.

This process is repeated for yellow (Y) and black (K) sequentially so that toner images of cyan (C), magenta (M), yellow (Y), and black (K) appear on the intermediate transfer medium 117. Are combined.

After the toner image of the black (K) color is transferred to the intermediate transfer medium 117, the turret 120 rotates 72 degrees counterclockwise so that the transparent developer 121TR faces the photosensitive medium 115. The electrostatic latent image for the transparent image for forming a transparent image is formed on the surface of the photosensitive medium 115 by the light beam scanned from the 130. The electrostatic latent image for the transparent image is formed by exposure of the entire image region in which the electrostatic latent images for cyan (C), magenta (M), yellow (Y), and black (K) images are combined, 130 scans the light beam based on the image information obtained by combining the image information of the respective colors C, M, Y, and K. For example, with reference to FIG. 4, the telephone image area into which the light beam is scanned is an area inside the boundary line of the letter 'A' drawing, and the non-image area is an area outside the boundary line of the letter A 'drawing.

On the other hand, the positive polarity transparent (TR) glossy toner contained in the transparent developer 121TR is not attached to the transparent image electrostatic latent image having a relatively positive polarity, and has a relatively negative polarity. A band is attached to the outer region of the electrostatic latent image for the transparent image so that a glossy transparent toner image is developed on the photosensitive medium 115.

The transparent toner image is charged from the positive polarity to the negative polarity by the toner charger 125 and transferred to the intermediate transfer medium 117. At this time, the light beam scanned from the optical scanner 130 in consideration of the circulation speed of the intermediate transfer medium 117 so that the color toner image formed on the intermediate transfer medium 117 and the boundary portion of the transparent toner image do not overlap. The timing of injection should be set appropriately.

The color toner image of each color (C, M, Y, K) and the transparent toner image are combined to finally transfer the toner image onto the printing medium P. Specifically, the printing medium P loaded in the paper feed cassette 102 is picked up by the pickup roller 105 and fed by the paper feed roller 106 to between the transfer roller 108 and the intermediate transfer medium 117. At this time, the toner image of the intermediate transfer medium 117 is transferred to the print medium P by the transfer bias applied to the transfer roller 108 at this time. The toner image transferred to the print medium P passes through the fixing unit 110 and is fixed to the print medium P by heat and pressure to form a photo image. The print medium P on which the photographic image is printed in this way is discharged by the discharge roller 113 and loaded on the discharge stage 103.

2 is a cross-sectional view of an electrophotographic image forming apparatus according to a second exemplary embodiment of the present invention.

Referring to FIG. 2, the electrophotographic image forming apparatus 200 according to the second embodiment of the present invention is a multi-path image forming apparatus similar to the first embodiment, and the inside of the case 201. Cylindrical photosensitive medium 215, five developing devices (220C, 220M, 220Y, 220K, 220TR) arranged in the vicinity of the photosensitive medium 215, optical scanner 230, intermediate transfer medium 217 And a transfer roller 208.

The photosensitive medium 215 has a photosensitive layer made of a photoconductive material formed on the outer circumferential surface of the metal drum by vapor deposition or the like. The optical scanner 230 is installed below the photosensitive medium 215, and scans a light beam corresponding to image information to the photosensitive medium 215. An electrostatic latent image is formed on the surface of the photosensitive medium 215 exposed by the light beam.

The five developing devices 220C, 220M, 220Y, 220K, and 220TR contain toners of cyan (C), magenta (M), yellow (Y), black (K) color, and colorless transparent solid powder, respectively. In order to take advantage of the glossiness of the photographic image, the toners employ a glossy gloss toner. In addition, color gloss toners are charged with a negative polarity, and transparent gloss toners are charged with a positive polarity. The toner applied to the second embodiment is the same as the toner applied to the first embodiment, and therefore, further description is omitted.

The four color developing units 220C, 220M, 220Y, and 220K each develop a color image of each color or a transparent image by supplying the toner contained therein to the photosensitive medium 215. The rollers 222C, 222M, 222Y, 222K, and 222TR are respectively provided. The developing units 220C, 220M, 220Y, 220K, and 220TR sequentially approach the photosensitive medium 2215 and supply the toner to color the colors C, M, Y, and K on the outer circumferential surface of the photosensitive medium 215. Develop a toner image or a transparent toner image. Although not shown, a supply roller, a doctor blade, and an agitator are provided inside the developing devices 220C, 220M, 220Y, 220K, and 220TR as in the case of the first embodiment.

A toner charger 225 is arranged around the photosensitive medium 215 to charge the transparent gloss toner, which is developed as a transparent image, on the outer circumferential surface of the photosensitive medium 215 with negative (-) polarity, such as color gloss toner. The toner charger 225 has the same configuration as the toner charger 125 (refer to FIG. 1) described in the first embodiment, and thus further description thereof will be omitted.

The intermediate transfer medium 217 is a transfer belt to which a color image or a transparent image made of toner is transferred, and is circulated by being supported by a plurality of support rollers. The length of the intermediate transfer medium 217 is equal to or longer than the length of the print medium P.

The transfer roller 208 is disposed to face the intermediate transfer medium 217. The transfer roller 208 is spaced apart from the intermediate transfer medium 217 while the toner is transferred to the intermediate transfer medium 217, and is then printed onto the intermediate transfer medium 217 when the toner image is completed. The intermediate transfer medium 217 is contacted to transfer it.

In addition, the image forming apparatus 200, as in the image forming apparatus 100 (see FIG. 1) of the first embodiment, and the fixing unit 210 for fixing the toner image transferred to the printing medium P to the printing medium P; And a pickup roller 105 for picking up the printing medium P on which the printing medium P is stacked, a pickup roller 105 for picking up the printing medium P loaded on the paper cassette 102 one by one, and a pickup roller 105. The feed roller 206 for feeding the printed medium P toward the transfer roller 208, the discharge roller 213 for discharging the print medium P out of the case 101, and the discharge roller 113. And a discharge tray 103 on which the print medium P discharged is loaded. In addition, the first waste toner cleaner 232 which scrapes and removes the waste toner remaining on the outer circumferential surface of the photosensitive medium 215 without being transferred to the intermediate transfer medium 217 from the photosensitive medium 215 and the print medium ( And a second waste toner cleaner 234 for scraping off the waste toner that is not transferred to P) and remaining in the intermediate transfer medium 217 from the intermediate transfer medium 217.

A method of printing a photographic image with the electrophotographic image forming apparatus 200 according to the second embodiment will be described.

First, the cyan developing device 220C approaches the photosensitive medium 215, and the optical scanning machine 230 scans the light beam corresponding to the image information of the visual (C) color onto the photosensitive medium 215, whereby the photosensitive medium ( 215) The electrostatic latent image for cyan (C) image corresponding to the cyan (C) color image is formed. Then, a negative (-) polar cyan (C) gloss toner contained in the cyan developer 220C is attached to this electrostatic latent image so that a glossy cyan (C) color toner image is developed on the photosensitive medium 215. The image is transferred to the intermediate transfer medium 217.

When the toner image formation of the cyan (C) color is completed on the intermediate transfer medium 217, the cyan developer 220C retreats and the magenta developer 220M approaches the photosensitive medium 215, and the optical scanner 230 is magenta. (M) A light beam corresponding to the color image information is scanned on the photosensitive medium 215 to form an electrostatic latent image for magenta (M) images. Then, a negative polarity magenta (M) gloss toner contained in the magenta developer (220M) is attached to this electrostatic latent image, and a toner image of glossy magenta (M) color is developed on the photosensitive medium 215, and this toner The image is transferred to the intermediate transfer medium 217.

At this time, in consideration of the circulation speed of the intermediate transfer medium 217, the scan timing of the light beam scanned from the optical scanning machine 230 is appropriately set, and the cyan (C) color toner formed on the intermediate transfer medium 217 first. The front end of the image and the front end of the toner image of magenta (M) color starting to be transferred from the photosensitive medium 215 to the intermediate transfer medium 217 are exactly matched.

This process is repeated for yellow (Y) and black (K) sequentially so that toner images of cyan (C), magenta (M), yellow (Y), and black (K) appear on the intermediate transfer medium 217. Are combined.

After the toner image of the black (K) color is transferred to the intermediate transfer medium 217, the black developer 220K retreats and the transparent developer 220TR approaches the photosensitive medium 215, and is scanned from the optical scanner 230. The electrostatic latent image for transparent image for forming a transparent image is formed on the surface of the photosensitive medium 215 by the light beam. The electrostatic latent image for the transparent image is formed by exposure of the entire image region in which the electrostatic latent images for cyan (C), magenta (M), yellow (Y), and black (K) images are combined, 230 scans the light beam based on the image information obtained by combining the image information of the respective colors C, M, Y, and K.

The positive polarity transparent (TR) gloss toner contained in the transparent developer 220TR does not adhere to the transparent image electrostatic latent image having a relatively positive polarity, and has a relatively negative polarity. A transparent transparent toner image adhered to an outer region of the electrostatic latent image for a transparent image is developed on the photosensitive medium 215.

The transparent toner image is charged from the positive polarity to the negative polarity by the toner charger 225 and transferred to the intermediate transfer medium 217. At this time, the scanning timing of the light beam scanned from the optical scanner 230 in consideration of the circulation speed of the intermediate transfer medium 217 so that the color toner image first formed on the intermediate transfer medium 217 and the transparent toner image do not overlap. Should be set appropriately.

The toner image obtained by combining the color toner image of each color (C, M, Y, K) and the transparent toner image is finally put on the printing medium P passing between the transfer roller 208 and the intermediate transfer medium 217. It is transferred and fixed to the print medium P by the fixing unit 210 to form a picture. The print medium P on which the photographic image is printed is discharged by the discharge roller 213 and loaded on the discharge table 203.

3 is a cross-sectional view of an electrophotographic image forming apparatus according to a third exemplary embodiment of the present invention.

Referring to FIG. 3, an electrophotographic image forming apparatus 300 according to a third embodiment of the present invention is a single-path image forming apparatus in which an image is directly transferred onto a printing medium P. Five developing machines 330C, 330M, 330Y, 330K, and 330TR are provided in the case 301, five optical scanners 325C, 325M, 325Y, 325K, and 325TR, and a transfer machine 310.

The five developing devices 330C, 330M, 330Y, 330K, and 330TR contain toners of cyan (C), magenta (M), yellow (Y), black (K) color, and colorless transparent solid powder, respectively. In order to take advantage of the glossiness of the photographic image, the toners employ a glossy toner. Four kinds of color gloss toners are charged with a negative polarity, and transparent gloss toners are charged with a positive polarity. The toner applied in the third embodiment is the same as the toner applied in the first embodiment, and therefore, further description is omitted.

Four color developing devices (330C, 330M, 330Y, 330K) and one transparent developing device (330TR) are used for the photosensitive medium (332C, 332M, 332Y, 332K, 332TR) and developing rollers (334C, 334M, 334Y, 334K, and 334TR). ). The developing rollers 334C, 334M, 334Y, 334K, and 334TR supply the toner contained in the developing machines 330C, 330M, 330Y, 330K, and 330TR to the photosensitive medium 332C, 332M, 332Y, 332K, and 332TR. A color image or a transparent image of each color (C, M, Y, K) is developed. Although not shown, a feed roller, a doctor blade, and an agitator are provided inside the developing devices 330C, 330M, 330Y, 330K, and 330TR as in the first embodiment.

On the other hand, around the photosensitive medium 332TR of the transparent developer 330TR, a toner for charging a transparent gloss toner, which is developed as a transparent image on the outer circumferential surface of the photosensitive medium 332TR, with a negative polarity, like a color gloss toner, Electricity 335 is disposed. The toner charger 335 has the same configuration as the toner charger 125 (refer to FIG. 1) described in the first embodiment, and thus further description thereof will be omitted.

The five photosensitive scanners 325C, 325M, 325Y, 325K, and 325TR corresponding to the five developing devices 330C, 330M, 330Y, 330K, and 330TR are used for image information on the photosensitive media 332C, 332M, 332Y, 332K, and 332TR. Scan the corresponding light beam. Electrostatic latent images are formed on the surfaces of the photosensitive media 332C, 332M, 332Y, 332K, and 332TR exposed by the light beam.

The transfer machine 310 is supported by a plurality of support rollers and circulates in the vertical direction. The transfer belt 311 transfers the print medium P from the bottom up, and causes the static electricity to transfer the print medium P to the transfer belt. Adsorption roller 312 which adsorb | sucks to 311 is provided. In addition, five transfer rollers 315C, which are disposed to face the photosensitive media 332C, 332M, 332Y, 332K, and 332TR of each of the developing devices 330C, 330M, 330Y, 330K, and 330TR with the transfer belt 311 interposed therebetween. 315M, 315Y, 315K, 315TR).

In addition, the image forming apparatus 300, like the image forming apparatus 100 (refer to FIG. 1) of the first embodiment, has a fixing unit for fixing the toner image transferred to the printing medium P to the printing medium P with heat and pressure ( 320), a paper feed cassette 302 on which the print medium P is loaded, a pickup roller 305 for picking up the print medium P sheet by sheet from the paper cassette 302, and the picked up print medium P. A paper feed roller 306, a discharge roller 323 for discharging the printed medium on which an image is printed out of the case 301, and a discharge tray 303 on which the print medium P discharged to the outside of the case 301 is loaded. It is provided.

A method of printing a photographic image with the electrophotographic image forming apparatus 300 having such a configuration will be described.

The five optical scanners 325C, 325M, 325Y, 325K, and 325TR scan light beams to the photosensitive media 332C, 332M, 332Y, 332K, and 332TR of the corresponding developing devices 330C, 330M, 330Y, 330K, and 330TR. As a result, electrostatic latent images are formed on the photosensitive media 332C, 332M, 332Y, 332K, and 332TR. In detail, the optical scanning machines 325C, 325M, 325Y, and 325K corresponding to the color developing devices 330C, 330M, 330Y, and 330K scan a light beam corresponding to the image information of each color (C, M, Y, K). On the surfaces of the photosensitive media 332C, 332M, 332Y, and 332K, electrostatic latent images for color images of respective colors C, M, Y, and K are formed. The optical scanning machine 325TR corresponding to the transparent developing device 330TR scans a light beam based on the image information obtained by combining the image information of the respective colors C, M, Y, and K, and thus the surface of the photosensitive medium 332TR. The entire image region in which the electrostatic latent images of the color images of each color (C, M, Y, K) are combined is exposed to form an electrostatic latent image for transparent images.

The negative polarity color gloss toner accommodated in the color developing units 330C, 330M, 330Y, and 330K are attached to the color image electrostatic latent images of the respective colors (C, M, Y, and K), so that the photosensitive media 332C, 332M, Glossy cyan (C), magenta (M), yellow (Y), and black (K) toner images are developed on the surfaces of 332Y and 332K. On the other hand, the positive polarity transparent gloss toner accommodated in the transparent developer 330TR is not attached to the electrostatic latent image having a relatively positive polarity, and has relatively negative polarization. A glossy transparent toner image is developed on the surface of the photosensitive medium 332TR by being attached to an external region of a commercial electrostatic latent image. The transparent toner image is charged from the positive polarity to the negative polarity by the toner charger 335.

The print medium P is picked up from the paper feed cassette 302 by the pickup roller 305, is fed by the paper feed roller 306, and static electricity is induced by the suction roller 312 to be attached to the transfer belt 311. Then, the conveyance belt 311 is conveyed at the same speed as the circulation driving speed.

The transfer bias is applied to the transfer rollers 315C, 315M, 315Y, 315K, and 315TR as the print medium P attached to the conveying belt 311 proceeds from the bottom to each color (C, M, Y, K). The color toner image and the transparent toner image are transferred to the print medium P in sequence. At this time, in order to prevent the color toner image and the transparent toner image from overlapping, the scanning timing of the light beam scanned from the optical scanning machine 325TR should be appropriately set in consideration of the circulation speed of the transfer belt 311.

The toner image, which is a color toner image of each color (C, M, Y, K) and a transparent toner image, is combined to be fixed to the print medium P by the fixing unit 320 to form a photo image. The print medium P on which the photographic image is printed is discharged by the discharge roller 323 and loaded on the discharge table 303.

Hereinafter, the features of the photographic image printed by the image forming apparatuses 100, 200 and 300 of the first, second and third embodiments will be described.

4 is a plan view illustrating an example of a print medium on which an image printed by the electrophotographic image forming apparatus of the present invention is displayed, and FIG. 5 is a partially enlarged cross-sectional view of the print medium of FIG. 4.

Referring to FIG. 4, the print medium P in which the letter 'A' is printed as a photographic image has an image area defined as green (G) defined inside the border of the letter 'A', and is outside the border of the letter 'A'. The non-image area limited to is shown in the color of the print medium (P), and the entire printing surface is glossy, so that it feels like a photographic image developed on photo paper.

Referring to FIG. 5, the print medium P has a uniform thickness of the toner distributed in the image area and a thickness of the toner distributed in the non-image area. Transparent (TR) glossy toners are distributed in the non-image region, and cyan (C) glossy toners and yellow (Y) glossy toners are alternately distributed in the image region to appear green (G). The transparent (TR) glossy toner does not overlap with the cyan (C) and yellow (Y) glossy toners in the image area and is present only in the non-image area.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. For example, the technical idea of the present invention may be applied to an electrophotographic image forming apparatus capable of printing only a mono color photographic image. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

According to the electrophotographic image forming apparatus for photographic image printing and the photographic image printing method of the present invention, it is possible to print a glossy image not only in the image region but also in the non-image region of the print medium.

In addition, the thickness of the gloss toner distributed in the image area and the non-image area of the print medium is uniform so that there is no difference in glossiness over the entire printing surface, and an image without printing irregularities due to the difference in the toner thickness can be printed. Can be.

Claims (28)

A photosensitive medium having a color image and a transparent image electrostatic latent image formed on a surface by exposure to light; A color developer which is charged with one polarity and contains a colored glossy toner, and supplies the color gloss toner to the color image electrostatic latent image to develop a color image on the surface of the photosensitive medium; A transparent image on the surface of the photosensitive medium by supplying the transparent glossy toner to the outer region of the electrostatic latent image for the transparent image, and containing a transparent glossy toner charged with a polarity different from that of the color glossy toner. A transparent developing device for developing the film; And, And an intermediate transfer medium on which the color image and the transparent image are sequentially transferred. According to claim 1, And the color image and the transparent image are transferred to an intermediate transfer medium without overlapping. According to claim 1, And a toner charger which charges the transparent gloss toner developed as a transparent image on the surface of the photosensitive medium with the same polarity as the color gloss toner. The method of claim 3, wherein And the toner charger is a corotron charger that includes a corona wire to charge the transparent groche toner in a non-contact state. According to claim 1, In order to print a multi-color image composed of a plurality of colors, the color developing device is provided with a plurality of containing glossy toners of different colors, On the surface of the photosensitive medium, a plurality of different color images and transparent images are sequentially developed. And the transparent electrostatic latent image is formed on the surface of the photosensitive medium by exposure of an entire image region where the plurality of different color image electrostatic latent images are combined. The method of claim 5, The color developer includes a cyan developer containing cyan color gloss toner, a magenta developer containing magenta color gloss toner, and a yellow color gloss toner. An electrophotographic image forming apparatus comprising a yellow developer and a black developer containing black (K) color gloss toner. The method of claim 5, And a plurality of color developing and transparent developing units are mounted on a rotating turret, and each developing unit sequentially faces the photosensitive medium and supplies toner to the photosensitive medium by rotating the turret. Type image forming apparatus. The method of claim 5, And a plurality of color developing devices and transparent developing devices are arranged stacked around the photosensitive medium, and each developing device sequentially approaches the photosensitive medium to supply toner to the photosensitive medium. According to claim 1, An electrophotographic image forming apparatus, wherein the transparent gloss toner is developed as a transparent image while being charged with a positive polarity, and the color gloss toner is developed as a color image while being charged with a negative polarity. . Photosensitive that is charged with one polarity, contains colored glossy toner, and is supplied to the color electrostatic latent latent electrostatic latent image formed by exposure to develop a color image on the surface. A color developer on which the medium is mounted; It is charged with a polarity different from that of the color gloss toner and contains a transparent glossy toner, and the transparent gloss toner is supplied to an outer region of a transparent image electrostatic latent image formed by exposure, so that a transparent image is formed on the surface. A transparent developer equipped with the photosensitive medium to be developed; And, And a transfer machine for transferring the color image and the transparent image onto a print medium. The method of claim 10, And the color image and the transparent image are configured to be transferred to a transfer machine without overlapping. The method of claim 10, And a toner charger which charges the transparent gloss toner developed as a transparent image on the surface of the photosensitive medium of the transparent developer with the same polarity as the color gloss toner. The method of claim 12, And the toner charger is a corotron charger that includes a corona wire to charge the transparent groche toner in a non-contact state. The method of claim 10, In order to print a multicolor image composed of a plurality of colors, the color developing device includes a plurality of glossy toners of different colors, each of which is provided with a photosensitive medium, A plurality of different color images are developed on the surface of the photosensitive medium of the plurality of color developing devices, and a transparent image is developed on the surface of the photosensitive medium of the transparent developing device. And the transparent electrostatic latent image is formed on the surface of the photosensitive medium by exposure of an entire image region where the plurality of different color image electrostatic latent images are combined. The method of claim 14, The color developer includes a cyan developer containing cyan color gloss toner, a magenta developer containing magenta color gloss toner, and a yellow color containing yellow color gloss toner. An electrophotographic image forming apparatus comprising a developing unit and a black developing unit containing black (K) black color glossy toner. The method of claim 10, An electrophotographic image forming apparatus, wherein the transparent gloss toner is developed as a transparent image while being charged with a positive polarity, and the color gloss toner is developed as a color image while being charged with a negative polarity. . A color exposure step of forming an electrostatic latent image corresponding to a color image on the surface of the photosensitive medium by exposure to light; A color image developing step of developing a color image by supplying a color glossy toner, which is charged with one polarity, to the color image electrostatic latent image; A color image intermediate transfer step of transferring the color image to an intermediate transfer medium; Forming a transparent electrostatic latent image on the surface of the photosensitive medium by exposure; A transparent image developing step of developing a transparent image by supplying a transparent glossy toner that is charged with a different polarity from the color gloss toner to an outer region of the electrostatic latent image for the transparent image; A transparent image intermediate transfer step of transferring the transparent image to an intermediate transfer medium; And, And a criminal image transfer step of transferring the color image and the transparent image transferred to the intermediate transfer medium together on a print medium. The method of claim 17, And the color image and the transparent image are transferred to the intermediate transfer medium without overlapping in the intermediate transfer step. The method of claim 17, And a transparent image charging step of charging the transparent gloss toner developed as a transparent image on the surface of the photosensitive medium with the same polarity as the color gloss toner. The method of claim 17, The color exposure step, the color image development step, and the color image intermediate transfer step are performed to cycle the glossy toners of different colors to form a multicolor image in which a plurality of different color images are combined on the intermediate transfer medium. , And in the transparent exposure step, the electrostatic latent image for transparent image is formed on the surface of the photosensitive medium by exposure of the entire image region where a plurality of different color image electrostatic latent images are combined. The method of claim 20, The different color gloss toners include cyan color gloss toner, magenta color gloss toner, yellow color gloss toner, and black color gloss toner. Photo image printing method, characterized in that made. The method of claim 17, And the color gloss toner of the color image developing step is charged with a negative polarity, and the transparent gloss toner of the color image developing step is charged with a positive polarity. A color exposure step of forming an electrostatic latent image corresponding to a color image on the surface of the photosensitive medium by exposure to light; A color image developing step of developing a color image by supplying a color glossy toner, which is charged with one polarity, to the color image electrostatic latent image; Forming a transparent electrostatic latent image for forming a transparent image on the surface of the photosensitive medium by exposure; A transparent image developing step of developing a transparent image by supplying a transparent glossy toner that is charged with a different polarity from the color gloss toner to an outer region of the electrostatic latent image for the transparent image; And, And a transfer step of transferring the color image and the transparent image to a print medium. The method of claim 23, wherein And the color image and the transparent image are transferred to a print medium so as not to overlap in the transfer step. The method of claim 23, wherein And a transparent image charging step of charging the transparent gloss toner developed as a transparent image on the surface of the photosensitive medium with the same polarity as the color gloss toner. The method of claim 23, wherein Performing the color exposure step and the color image development step on the gloss toners of different colors to develop a plurality of different color images on a plurality of photosensitive media, And in the transparent exposure step, the electrostatic latent image for transparent image is formed on the surface of the photosensitive medium by exposure of the entire image region where a plurality of different color image electrostatic latent images are combined. The method of claim 26, The different color gloss toners include cyan color gloss toner, magenta color gloss toner, yellow color gloss toner, and black color gloss toner. Photo image printing method, characterized in that made. The method of claim 23, wherein And the color gloss toner of the color image developing step is charged with a negative polarity, and the transparent gloss toner of the color image developing step is charged with a positive polarity.

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