JPH10254162A - Electrophotographic print forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance tone reproduction and color fidelity reproduction, in the case of forming a color photographic print which is obtained by exposing a uniformly and electrostatically charged electrophotographic photoreceptor by light including image information so as to form an electrostatic latent image, then, developing the electrostatic latent image by plural kinds of color toner so as to form a color toner image, and then, transferring the color toner image to a printing paper. SOLUTION: The toner image formed on the photoconductive body 250 of the uniformly and electrostatically charged photoreceptor drum 254 is transferred to an intermediate transfer medium 266 once, then, the image is retransferred from the intermediate transfer medium 266 to the printing paper H, besides, the printing paper H satisfying the following conditions is used; 90<L*, -2<a*<2 and -10<b*<2 as for tone L*a*b*, and also, the paper H whose glossiness is >10 is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method for making a color print of an image by electrophotography, and more particularly to transferring a toner image to a final print sheet via transfer to an intermediate transfer medium. The present invention relates to such an electrophotographic print creation method.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 5-50027
As shown in No. 8, a uniformly charged electrophotographic photosensitive member is exposed to light modulated based on an image signal indicating a continuous tone image to form an electrostatic latent image, and the electrostatic latent image is formed. There is known a method of developing an image by toner development to obtain a toner image, and then transferring the toner image to print paper to create an electrophotographic print. In this type of electrophotographic print creation method, it has been proposed to create a color print by superimposing three or four color toner images on print paper.

[0003] Various attempts have been made to obtain silver halide photographic quality prints by electrophotography.
For example, Japanese Patent Application Laid-Open No. 5-281863 discloses a method in which a toner image on an electrophotographic photosensitive member is temporarily transferred to an easily transferable intermediate transfer medium, and then the toner image is transferred from the intermediate transfer medium to final print paper. It has been disclosed.

There have been various attempts to improve the image quality of photographic prints by such an electrophotographic method by selecting print paper. For example, JP-A-1-
Japanese Patent Publication No. 245265 and Japanese Patent Publication No. 5-82940 disclose the use of print paper having a glossiness enhanced by providing a coating layer on the surface.

Conventionally, in addition to the print paper having the above-mentioned coating layer, various types of print paper, such as ordinary high-quality paper, have been used, but these papers have L ^* a ^* b ^* space and L ^* a ^* b ^* space ^. It is generally in the range of <90, -2 <a ^* <2, -2 <b ^* <10, with a gloss of less than 10 and an average surface roughness of more than 1 μm.

[0006]

The printing paper provided with the above-mentioned coating layer has a smoother surface than general high-quality paper, which is an uncoated paper, and adheres uniformly to the electrophotographic photosensitive member. Theoretically, when such print paper is used, a clear toner image should be obtained. However, in practice, it has been found that even when print paper provided with this coating layer is used, the image quality of the print is almost the same as when using high quality paper. Therefore, the printing paper provided with the coating layer is hardly used in practice.

On the other hand, a printing paper provided with a coating layer has a high glossiness in a blank portion or a high density portion having a very large amount of toner, but has a high glossiness in a halftone portion or a highlight portion having a relatively small amount of toner. However, the glossiness is rather reduced due to the unevenness caused by the adhesion of the toner, and the gloss balance of the entire image is deteriorated. For this reason, it is difficult to obtain a silver halide photographic grade print using ordinary photographic paper even when using print paper provided with this coating layer.

The present invention has been made in view of the above circumstances, and provides a high quality and high quality color print comparable to silver halide photography, especially a color print excellent in gradation reproducibility and color fidelity reproducibility. An object of the present invention is to provide an electrophotographic print creation method that can be created.

[0009]

According to the present invention, there is provided a method for producing an electrophotographic print, which comprises exposing a uniformly charged electrophotographic photosensitive member to light containing image information to form an electrostatic latent image. A method of developing the electrostatic latent image with a plurality of color toners to form a color toner image, and transferring the color toner image to printing paper to form a color electrophotographic print; The transferred toner image is temporarily transferred to an intermediate transfer medium, and is then transferred from the intermediate transfer medium to print paper.
The glossiness is 10 or more and the average surface roughness is 1 μm or less.

[0010] As the print paper, L ^* a ^*
90 <L ^* , -2 <a ^* <2, -10 <b in b ^* space
^{* It} is desirable to use the one in the range of <2, and furthermore, the reflectance for light in the wavelength range of 450 to 700 nm is high.
It is more preferable to use printing paper having a reflectance of 80% or more and a difference between the maximum reflectance and the minimum reflectance for light in this wavelength range of 5% or less.

On the other hand, as the intermediate transfer medium, it is desirable to use an intermediate transfer medium capable of adhesively transferring a toner image to an adhesive layer formed on the surface thereof.

[0012]

According to the electrophotographic print forming method of the present invention, the color toner image formed on the electrophotographic photoreceptor is temporarily transferred to an intermediate transfer medium which is easy to transfer, and then transferred from the intermediate transfer medium to print paper. Therefore, the transfer rate of the toner can be sufficiently increased. For example, as disclosed in Japanese Patent No. 2568273, when using an intermediate transfer medium that adhesively transfers a toner image to an adhesive layer formed on the surface, it is necessary to obtain a toner transfer rate of 100% or extremely close thereto. Can also. If so, the color toner image formed on the electrophotographic photoreceptor can be transferred to print paper as it is or in a state very close to it, so that a color print excellent in gradation reproducibility and color fidelity reproducibility can be created. become.

[0013] In addition, by using a printing paper having a glossiness of 10 or more and an average surface roughness of 1 µm or less, the color reproduction range is significantly expanded as compared with the related art. In addition, by using print paper having a gloss level of more than 10, the gloss of the color print surface is increased, and a print having the same impression as a silver halide photograph using photographic paper can be obtained.

Further, as this print paper, L ^* a
90 <L ^* , -2 <a ^* <2, -10 <in the ^* b ^* space
When a print paper in the range of b ^* <2, that is, a print paper that is extremely white and has high saturation, is used, the color toner image transferred to the print paper does not become dull, the saturation is improved, and the color is further improved. Color prints with excellent fidelity can be created.

As described above, according to the photographic print producing method of the present invention, it is possible to produce a high quality and high quality color print comparable to a silver halide photograph.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an example of an electrophotographic printer for implementing the method of the present invention, and FIG. 2 shows a signal processing system for supplying image data to the electrophotographic printer.

First, the electrophotographic printer shown in FIG. 1 will be described. As shown, in this device, the photoconductor
The toner image forming means disposed around the photosensitive drum 254 provided with the photoconductor drum 250 forms a toner image on the peripheral surface thereof while being rotated in the direction of the arrow. The toner image forming unit includes a charger 251, an exposure unit 252, a developing unit 253, a drum drying unit 257, a static eliminator 298, a cleaning unit 248, and an erasing lamp 27 (eraser) arranged along the rotation direction of the photosensitive drum 254. ) And so on.

The exposing unit 252 includes, for example, a semiconductor laser,
A laser light source 252a composed of a He-Ne laser or the like, and an optical modulator such as an AOM (acousto-optic light modulator) for modulating the intensity of a light beam (laser beam) L emitted therefrom.
252b, an optical deflector 252c such as a polygon mirror that reflects and deflects the modulated light beam L and scans the photosensitive drum 254 in a direction substantially perpendicular to its rotation direction, And a scanning lens 252d composed of an fθ lens that focuses the light beam to a uniform beam diameter.

Here, the light modulator 252b is used only when writing an image by the intensity modulation method described later, and when writing an image by the area modulation method, the light beam L is applied to the light modulator 252b. Switching can be performed by a method (not shown) so as not to pass.

The developing device 253 may be any developing device capable of developing the electrostatic latent image on the photoconductor 250 with toner. For example, the developing device 253 may be a liquid developing device disclosed in Japanese Patent Application Laid-Open No. 1-62014 filed by the present applicant. A developing device can be used. As the toner, a liquid developer (liquid toner) in which fine toner particles having electric charges are dispersed in an insulating carrier liquid is preferably used, but a dry toner may be used.

Here, the developing unit 253 is used for forming a color image. The developing unit 253 for Y (yellow) toner, the developing unit 253M for YM (magenta) and the developing unit 253C for C (cyan) or three colors are used. And a developing device for four colors, in which a developing device 253B for B (black) is added, can be used in turn.

The drying means 257 is a squeeze roller 257a which rotates in a non-contact manner at a high speed in a direction opposite to the rotation direction of the photosensitive drum 254 to scrape off the insulating liquid attached to the photoconductor 250 together with the toner particles; A blade 257b for rubbing off the insulating liquid scraped off by the roller and removing most of the insulating liquid; however, hot air for drying the toner image on the squeeze roller 257a and the photoconductor 250. Or dryer 257c to supply hot air
have. A plurality of dryers 257c may be provided and used separately for drying the squeeze roller 257a and for drying the toner image on the photoconductor 250.

The static eliminator 298 is an AC corona static eliminator that zeroes the surface potential of the photoconductor 250 of the photosensitive drum 254 by charging it with an AC corona.

The cleaning means 248 cleans the photoconductor 250 after the transfer of the toner image, and comprises a flexible base 248a impregnated with a cleaning liquid CL such as an insulating carrier liquid used for the liquid developer, and a flexible base 248a. Substrate 248a is replaced with photoconductor 250
A pressing roller 248b for pressing the surface of the flexible substrate 248a with the cleaning liquid CL, a first roller 248c for winding and storing an unused flexible substrate 248a, and winding the used flexible substrate 248a It has a second roller 248d, a tension roller (not shown), a dryer 248e for drying the surface of the cleaned photoconductor 250, and a known driving means (not shown). The outer surface of the conductor 250 is cleaned.

The erasing lamp 27 is used to completely remove the electric charge from the photoconductor 250 of the photosensitive drum 254.
4 is to irradiate light.

In this embodiment, almost 100% of the toner image on the photoconductor 250 of the photosensitive drum 254 is transferred to an adhesive layer on an intermediate transfer medium to be described later.
Although it is not necessary to provide the surface, it is preferable to provide the surface so that the surface of the photoconductor is always clean before uniformly charged.

The adhesive transfer means 256 is moved in the direction of arrow B by a known means to be in contact with the photoconductor 250 around the photosensitive drum 254, and is moved in the direction B 'to move the photoconductor 250. Transfer roller 255, which can be at a position separated from the image receiving sheet 266, an image receiving sheet supply roller 263 for winding and storing the image receiving sheet 266, and an image receiving sheet adhered to the release sheet 296 sent out from the image receiving sheet supply roller 263. Sheet
The nip rollers 258a and 258b sandwich the belt 266, and a release sheet take-up roller 264 that winds the strip-shaped release sheet 296 separated from the image receiving sheet 266 at a position sandwiched by the nip rollers 258a and 258b. The image receiving sheet 26
6 has an adhesive layer as a transfer medium on one surface side, and this adhesive layer side is attached to a release sheet 296.

Downstream of the transfer roller 255, as a means for re-transfer to the final support, a paper stocker 261 for storing print paper H having a toner receiving layer with the toner receiving layer facing upward, A sheet sending roller 260 provided near the sheet outlet adsorbs the sent print sheet H, and overlaps the toner receiving layer on the sheet H with the toner image on the adhesive layer of the image receiving sheet 266 so as to face each other. Paper holding belt 295 that transports print paper H
And print paper H superimposed on the image receiving sheet 266
A pair of thermocompression transfer rollers 259a and 259b for thermocompression bonding the image receiving sheet 266 with the image receiving sheet 266, an extraction guide 299 for taking out the printing paper H on which the toner image has been transferred, and a method for reusing the image receiving sheet 266 after this transfer. And an image receiving sheet winding roller 262 for winding. The characteristics of the print paper H will be described later in detail.

Each of the thermocompression transfer rollers 259a and 259b has a heat source therein and is heated to a predetermined temperature, and is driven to rotate in a direction indicated by an arrow by driving means (not shown).

In this embodiment, the release sheet 296 that protects the adhesive layer of the image receiving sheet 266 is used. For example, if the back surface of the image receiving sheet 266 is provided with release properties, It is not necessary to use it.

Next, a process for forming a color print will be described. In the apparatus of FIG.
The rotation of the photoconductor 250
Moves relative to the charger 251, and is uniformly charged by the charger 251. The uniformly charged photoconductor 250 is irradiated with a light beam L modulated according to image data via a light deflector 252c and a scanning lens 252d. The modulation of the light beam L will be described later in detail.

The light beam L is deflected by the light deflector 252c and scans (main scans) the photoconductor 250 one-dimensionally.
The sub-scanning of the light beam L is performed by rotating the photosensitive drum 254, and the photoconductor 250 is eventually scanned two-dimensionally by the light beam L. As described above, the light beam L is modulated based on the image data. Therefore, on the photoconductor 250 irradiated with the light beam L, an electrostatic latent image of the image carried by the image data is formed. It is formed.

This electrostatic latent image is developed into a toner image by the developing device 253. The developing device 253 contacts the photoconductor 250 with a liquid developer obtained by dispersing charged fine toner particles in an insulating carrier liquid, and attaches the toner particles to the photoconductor 250 by electrostatic attraction. Thus, the electrostatic latent image is developed with toner. Thus, the photosensitive drum 254
The toner image formed thereon is dried by drum drying means 257. In the present invention, a dry toner may be used instead of the liquid toner described above.

On the other hand, the image receiving sheet 266 is
The sheet 263 is sent out from the release sheet 263 while being adhered to the strip-shaped release sheet 296, and is peeled off from the release sheet 296 at a position sandwiched by the nip rollers 258a and 258b. Peeled release sheet 29
6 is taken up by a release sheet take-up roller 264.
Then, the image receiving sheet 266 from which the release sheet 296 has been peeled off is
It is suspended by the transfer roller 255 with the adhesive layer facing outward.

When it is detected or determined by a known means that the toner-developed portion on the photoconductor 250 has been sent to a position immediately before the position facing the transfer roller 255, the photosensitive member has been detected. The transfer roller 255, which has been separated from the drum 254,
Move in the direction. When the transfer roller 255 moves as described above, the transfer roller 255 is driven to rotate by the photosensitive drum 254, and the adhesive layer side of the image receiving sheet 266 suspended there is pressed against the photoconductor 250.

At this time, if the adhesive force between the toner particles forming the toner image and the photoconductor 250 is made smaller than the adhesive force between the adhesive layer and the toner particles and the cohesive force between the toner particles, the toner particles Is easily and completely separated from the photosensitive drum 254 by lightly pressing the adhesive layer of the image receiving sheet 266, and almost 100% is transferred to the adhesive layer of the image receiving sheet 266. Thus, the toner image on the photoconductor 250 is adhesively transferred to the adhesive layer of the image receiving sheet 266.

Thereafter, the transfer roller 255 moves in the direction B 'and separates from the photosensitive drum 254. The image receiving sheet 266 on which the toner image on the photoconductor 250 is adhesively transferred is sent between the heated thermocompression rollers 259a and 259b, and the image receiving sheet
266 and print paper H are bonded together such that the adhesive layer and the toner receiving layer face each other. The image receiving sheet 266 and the printing paper H that have been adhered to each other are heated and pressed between the thermocompression transfer rollers 259a and 259b, and then conveyed while being cooled.

During this time, the toner is melted by thermocompression and fused with the toner particles. At the same time, the toner is firmly fixed to the toner receiving layer of the printing paper H. Therefore, the adhesion between the toners, that is, the cohesive force increases, and the toner is fixed. The adhesive force between the toner and the print paper H increases. When the toner receiving layer of the print paper H has a substance that increases the toner adhesion by thermocompression bonding or the like, the adhesion further increases.

Here, the temperature and pressure for heating and pressing may be appropriately determined according to the toner, the adhesive layer, the printing paper, and the like. However, the heating temperature must be set at least equal to or higher than the softening point of the coating polymer of the toner. The temperature is preferably from 120 to 150 ° C., and the pressure is preferably from 0.05 to 0.8 kg / cm ² .

Thereafter, the image receiving sheets 266 adhered to each other
The print paper H is peeled off by the removal guide 299 or the like. At this time, the adhesive force between the toner and the adhesive layer needs to be smaller than the cohesive force between the toners and the adhesive force between the toner and the printing paper H. The cooling at the nip roller needs to be determined appropriately. The temperature for cooling by the nip roller may be appropriately determined according to the toner, the adhesive layer, the printing paper H, and the like.
Is preferred.

After heat fixing and cooling, almost 100% of the toner image on the adhesive layer of the image receiving sheet 266 is transferred to the toner receiving layer of the printing paper H. Then, the image receiving sheet 266 is peeled from the print paper H. The image receiving sheet 266 is taken up by a take-up roller 262 for reuse.

On the other hand, the print paper H on which the toner image has been formed is conveyed to a predetermined position while being held on the paper holding belt 295, where it stands by until the transfer of the second color toner image. The second color toner image is a photosensitive drum as described above.
254, an image receiving sheet that is an intermediate transfer medium
The adhesive transfer is performed on the transfer roller 266, and the transfer is performed toward the transfer roller 255. The printing paper H is conveyed and sent at a timing such that the second color toner image on the image receiving sheet 266 overlaps the first color toner image, and is nipped by the transfer roller 255 so as to overlap the image receiving sheet 266. . As a result, the second color toner image is transferred over the first color toner image on the print paper H.

Print paper H having a second color toner image
Is transported to a predetermined position while being held on the paper holding belt 295, as described above, and waits for the next toner image transfer. In the case of a color image consisting of three or four colors, a full-color image is formed by repeating the above operation three or four times.

In this embodiment, the image receiving sheet 266 is taken up by the winding roller 262 and is reused. However, the present invention is not limited to this. After the image receiving sheet 266 is used, the image receiving sheet supply roller 263 may be used. The used image receiving sheet 266 may be wound up by the take-up roller 262 after reversing and returning the image receiving sheet 266 to a predetermined position and immediately reusing it.

After the adhesive transfer of each color toner image, the photoconductor 250 is neutralized by a neutralizer 298.
The toner is cleaned by the cleaning unit 248, and becomes ready to be used for the next toner image formation.

Next, the modulation will be described with reference to FIG. 2 showing an electrical configuration for modulating the light beam L based on image data.

For example, digital image data D carrying a color multi-tone image generated by subjecting a signal obtained by photoelectrically reading a photographic film to amplification, A / D conversion, etc., is processed by an image processing unit 285. Is input to The image data D includes color density gradation conversion means 230 for converting density data, color data and gradation data of image data, saturation conversion means 231 for converting saturation data, gamma correction means 232, and the number of pixel data. Digital magnification conversion means 234 for converting, frequency processing means 235 for performing frequency processing, dynamic range conversion means 236 for converting a dynamic range, and a D / A converter 237 are sequentially passed to thereby convert analog image data D '. Generated.

Here, as a method of forming a full-color continuous tone image by electrophotography, a so-called intensity modulation in which a latent image is formed by modulating the intensity of a laser beam applied to a photoreceptor in accordance with the image density and toner development is performed. A so-called area modulation method in which a continuous tone image is represented by binarized dots and the dot density is changed according to the image density is known.

The configuration shown in FIG. 2 is configured so that both of these modulation methods can be applied. When the intensity modulation method is applied, as shown by a symbol (b) in FIG. 2, the image data D ′ is used as it is as an input signal to the optical modulator 252b, and the light beam L is applied to the optical modulator 252b. Is intensity-modulated.

On the other hand, when the area modulation method using a line screen implemented in the present embodiment is applied, FIG.
As shown in the specific example of the screen generator, the triangular wave signal generated from the triangular wave generator 241 in synchronization with the signal from the line clock generator 240 for generating the reference clock of the line screen, and the image data D ′ are The comparison is performed by the comparator 242, thereby forming a line screen image signal C having a pulse width corresponding to the size of the image data D '.

Laser drive circuit for driving laser light source 252a
The line screen image signal C is input to 243, and the light beam L emitted from the laser light source 252a is pulse width modulated based on the signal C. As a result, the photosensitive drum 254
On the photoconductor 250, an electrostatic latent image having a discrete surface potential is formed. In this example, a triangular wave is used to form a line screen. However, the present invention is not limited to this, and a signal having a sine wave or a similar waveform may be generated.

In this embodiment, the screen generator for each color has a raster pitch in the sub-scanning direction of 400 lines / line.
It outputs an image signal based on a line screen equivalent to inches, but the timing of generating the line clock from the line clock generator 240 differs for each color component screen generator. The screen angles are set to be different from each other while the screen pitch is substantially equal.

That is, in this case, in the screen generator for the single-color image forming unit that generates the yellow image (Y), as shown in FIG. Is set to 188 lines / inch, and a screen generator for a single-color image forming unit for generating a magenta image (M) is shown in FIG.
As shown in FIG. 5, when the screen angle is 0 ° in the main scanning direction, the screen angle is 63.5 °, and the screen pitch is 224 lines /
A screen generator for a single-color image forming unit that generates a cyan image (C) is set when the screen angle is 0 ° in the main scanning direction, as shown in FIG. 63.5 °
A line screen having a screen pitch of 224 lines / inch is set. In a screen generator for a single-color image forming unit that generates a black image (K), as shown in FIG. Is set to 0 °, a line screen is set at 90 ° and the screen pitch becomes 200 lines / inch.

More specifically, the line screen for the black image (K) has a basic structure of 200 lines and 90 ° which is generally used.

The line screen for the yellow image (Y) is a line screen which is the source in the main scanning direction, which is 133 lines.
The line screen is 90 ° (the pitch width is 1.5 times larger than the 200-line screen), and the line screen for each line is １ ／ of the 133-line 90 ° line screen pitch (in other words, the basic structure). (Corresponding to 1/2 of the 200-line line screen pitch), and raster scanning is performed. As a result, a 188 line 45 ° line screen is obtained.

Further, the line screen for the magenta image (M) has a line screen that is the source in the main scanning direction.
It has a basic structure of 0 lines and 90 °, and the line screen for each line is shifted by ４ of the line screen pitch of the above basic structure and raster-scanned. As a result, 224 lines 63.5 Obtained as a line screen with the number of lines of ° and the screen angle.

The line screen of the cyan image (C) is the same as the line screen which is the source in the main scanning direction.
It has a basic structure of 0 °, and the line screen for each line is shifted by ／ of the line screen pitch of the above basic structure, and raster scanning is performed. As a result, 224 lines, −63.5 are obtained. Obtained as a line screen with the number of lines of ° and the screen angle.

Next, a description will be given of a difference in print image quality with the print paper H. In the present invention, as described above, the printing paper H having a glossiness of 10 or more and an average surface roughness of 1 μm or less is used. Assuming that this condition was satisfied, the print papers of Examples A and B were prepared, while Comparative Examples A and B deviated from this condition.
Commercial printing papers of B, C, D and E were prepared.
The values of L ^* a ^* b ^* , glossiness and average surface roughness of these print papers are shown in Table 1 below. FIG. 7 shows their spectral reflectances. In FIG. 7,
The prominent reflectance exceeding 100% (1.0) near the wavelength of 430 nm is due to the influence of the fluorescent light generated from the printing paper.

[0059]

[Table 1]

Here, the color tone L ^* a ^* b ^* value and the spectral reflectance were measured using SPM100-2 manufactured by Gretag. The color tone L ^* a ^* b ^* value was measured with respect to reflected light in a D55 2 degree visual field.

On the other hand, the glossiness is measured according to JIS-K5400-19.
According to No. 79, specular glossiness at 20 degrees was measured using a Model 500 Pico Gloss Master manufactured by Erichsen AG of Germany.
The average surface roughness was measured using Surfcom manufactured by Tokyo Seimitsu Co., Ltd.

As shown in FIG. 7, the print papers of Examples A and B have a reflectance of 80% or more with respect to light in the visible wavelength range of 450 to 700 nm, and light in this wavelength range. The difference between the maximum reflectance and the minimum reflectance is 5
% Or less.

The print papers of the above seven examples were used in the apparatus shown in FIG. 1 and color toner images were transferred to the respective print papers as described above to produce color photographic prints. Note that the input image data D may be 8 bits or more for each color gradation of RGB,
An image signal obtained by reading a color photographic film at a resolution of 250 dpi (dots perinch) or more was used. The beam spot diameter of the light beam L for exposure was 100 μm or less, and the developing toner used had an average particle diameter of 1 μm or less.

The result of the visual evaluation of the color fidelity reproducibility of the color photographic print for each sheet prepared as described above is shown below.
It is also shown in Table 1 above. The evaluation symbols ○, Δ and × in Table 1 indicate “good (comparable to conventional silver halide photography)”, “OK” and “poor”, respectively. As shown here, according to the method of the present invention, that is, when the print papers of Examples A and B are used, compared with the print papers of other comparative examples A to E,
It was confirmed that the color fidelity of color photographic prints was improved.

Next, another example of an electrophotographic printer suitable for carrying out the method of the present invention will be described. Note that, in the following drawings, the same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description thereof will be omitted.

In the apparatus shown in FIG. 1, an image receiving sheet having an adhesive layer on its surface is used as an intermediate transfer medium. In the electrophotographic printer shown in FIG. 8, an intermediate transfer drum 270 wound with a conductive film is used as a photosensitive drum. The toner image on the photosensitive drum 254 is electrostatically transferred onto the conductive film by applying a potential having a polarity opposite to that of the toner charge to the conductive film. A configuration in which an image is further transferred to a print sheet H is employed. In addition, about such a structure, for example,
No. 341666 provides a more detailed description.

In the electrophotographic printer shown in FIG.
The toner image on the photosensitive drum 254 is primarily transferred to the intermediate transfer belt 271, and the unfixed toner image is further transferred to the print paper H. Such a configuration is described in, for example, JP-B-49-209 and JP-A-6-209.
A detailed description is given in 2-206567.

Further, in the electrophotographic printer shown in FIG. 10, toner images of three colors or four colors are formed on a plurality of photosensitive drums 254, respectively, and these toner images are positioned on the intermediate transfer belt 271. The toner image is transferred onto the printing paper H, and the full-color toner image is further transferred to the printing paper H.
Is adopted. Such a configuration is described in detail in, for example, JP-A-8-179545.

In the present invention, it is desirable to transfer 100% of the toner image formed on the electrophotographic photosensitive member to printing paper using the intermediate transfer belt 271 and the image receiving sheet 266 having an adhesive layer. Generally, not limited to 9
If the transfer is 0% or more, preferably 95% or more, the gradation reproducibility and the color faithful reproducibility of the color photographic print can be surely enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an example of an electrophotographic printer for implementing the method of the present invention.

FIG. 2 is a block diagram showing an electrical configuration for modulating an exposure beam in the apparatus of FIG.

FIG. 3 is a schematic diagram showing a line screen for a yellow image.

FIG. 4 is a schematic diagram showing a line screen for a magenta image.

FIG. 5 is a schematic diagram showing a line screen for a cyan image.

FIG. 6 is a schematic diagram showing a line screen for a black image.

FIG. 7 is a graph showing the spectral reflectance of print paper used in the present invention and print paper as another comparative example.

FIG. 8 is a schematic side view showing another example of an electrophotographic printer for implementing the method of the present invention.

FIG. 9 is a schematic side view showing still another example of an electrophotographic printer for implementing the method of the present invention.

FIG. 10 is a schematic side view showing still another example of an electrophotographic printer for implementing the method of the present invention.

[Explanation of symbols]

 250 Photoconductor 251 Charger 252 Exposure unit 253 Developing unit 254 Photoreceptor drum 266 Image receiving sheet having adhesive layer 270 Intermediate drum 271 Intermediate transfer belt L Light beam (exposure light) H Print paper

[Procedure amendment]

[Submission date] April 10, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0059

[Correction method] Change

[Correction contents]

[0059]

[Table 1]

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 3

FIG. 4

FIG. 2

FIG. 5

FIG. 6

FIG. 7

FIG. 8

FIG. 10

FIG. 9

Claims (4)

[Claims] 1. A uniformly charged electrophotographic photosensitive member is exposed to light containing image information to form an electrostatic latent image, and the electrostatic latent image is developed with a plurality of color toners to form a color toner image. Forming an electrophotographic print by transferring the color toner image to print paper, wherein the toner image formed on the electrophotographic photosensitive member is temporarily transferred to an intermediate transfer medium, and An electrophotographic print making method, comprising transferring to a print sheet and using, as the print sheet, a sheet having a gloss of 10 or more and an average surface roughness of 1 μm or less. 2. The printing paper according to claim 1, wherein L ^* a ^* b ^*
In space, 90 <L ^* , -2 <a ^* <2, -10 <b ^*
2. The method for producing an electrophotographic print according to claim 1, wherein the one in the range of <2 is used. 3. The printing paper according to claim 1, wherein a wavelength range of the printing paper is 450 to 450.
The reflectance for light of 700 nm is 80% or more, and the difference between the maximum reflectance and the minimum reflectance for light in this wavelength range is 5%.
%. The method for producing an electrophotographic print according to claim 1, wherein the content is not more than%. 4. The electrophotographic print according to claim 1, wherein the intermediate transfer medium adhesively transfers the toner image to an adhesive layer formed on the surface of the intermediate transfer medium. Method.