JP3185859B2 - Image processing apparatus and image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a color printer or a color copying machine for forming a color image on a recording medium by using a color image signal, and an image processing section of such an image forming apparatus. In particular, the image processing apparatus, in particular, on a recording medium having a surface provided with a thermoplastic transparent resin layer, by a special electrophotographic method that can be called a thermal transfer simultaneous fixing method, a color image using a colored toner and transparent particles. The present invention relates to an image forming apparatus to be formed and an image processing apparatus constituting an image processing unit of such an image forming apparatus.

[0002]

2. Description of the Related Art In recent years, in addition to the development of computers, maintenance of communication networks, and the emergence of large-capacity storage media,
2. Description of the Related Art With the spread of scanners and digital cameras, photographic image data is rapidly spreading, and there is an increasing demand to print out image data such as photographic image data with high quality.

[0003] In the field of photographic film, there is an increasing demand for multi-functional printouts of higher image quality by performing image processing and image editing by digitizing images instead of analog output.

There are various methods for forming a color image on paper or the like, including printing, an electrophotographic method, an ink jet method, and the like. Among them, the electrophotographic method has a wide range of applications such as the ability to transfer a color toner image onto plain paper without the need for photosensitive paper. Recently, high-speed fixing has been performed, and fixing property has been improved by applying instantaneous heating and pressure to a toner image.

However, an image formed by a conventional electrophotographic image forming apparatus becomes an image having no gloss or uneven gloss due to the following reasons.

In the electrophotographic system, generally, 5 to 12 μm
A thermoplastic toner having a particle diameter of 0.3 to 1.3 mg / cm ² per color is transferred onto the recording medium over one to four layers. However, although the toner is softened and melted when heated and melted, not all of the toner penetrates into a recording medium such as paper even in a heated and pressurized state.
It is formed to be raised about μm.

As a result, the image formed on the recording medium has a relatively high gloss in the solid image portion, but the lines and dots structure are raised in the halftone region and the highlight region, and the entire image is uneven. And the scattering of incident light increases. Therefore, in the case of an image having a relatively large density gradation such as a person image, the image becomes a mixed image of a high gloss area and a low gloss area, and the user feels strange. Further, it is known that such uneven images have low color reproducibility and low clarity due to the influence of irregular reflection on the image surface.

[0008]

Therefore, as an electrophotographic image forming apparatus, an electrostatic latent image of each color formed on one or a plurality of photoconductors is developed into a toner image and superimposed on an intermediate transfer member. Together, the intermediate transfer body on which the multicolor toner images have been transferred and the recording medium are sandwiched and brought into close contact, and the intermediate transfer body and the recording medium are heated and pressurized in that state, and then cooled or cooled, and then A method of separating a recording medium from an intermediate transfer member together with a toner image has been proposed by Japanese Patent Application No. 7-329159 (filed on December 18, 1995).

Further, in a special electrophotographic system which can be called a simultaneous thermal transfer fixing system, a method using a recording medium provided with a thermoplastic transparent resin layer on the surface is disclosed in Japanese Patent Application No. 8-155615. (June 1, 1996
7th application).

More specifically, in this method, as shown in FIG. 11A, a belt-like intermediate transfer circuit circulating while moving in the direction of an arrow 6a between a heating roll 8 and a pressure roll 9 is used. The toner image 15 of each color is transferred onto the body 6 from the photoreceptor not shown in the figure, and the recording medium 20 having the thermoplastic transparent resin layer 22 formed on the base material 21 is transferred between the heating roll 8 and the pressure roll 9. The intermediate transfer body 6 holding the toner image 15 and the recording medium 20 are passed through the heating roll 8 and the pressure roll 9.
The intermediate transfer body 6 and the recording medium 20 are heated and pressed by the heating roll 8 and the pressure roll 9 in this state.

As a result, the toner image 15 on the intermediate transfer body 6 and the thermoplastic transparent resin layer 22 on the surface of the recording medium 20 are melted, and as shown in FIG.
5 penetrates into the thermoplastic transparent resin layer 22.

Thereafter, the intermediate transfer body 6 and the recording medium 20
With the movement, the intermediate transfer body 6 and the recording medium 20 are cooled by the cooler 13 to coagulate and solidify the toner image 15 that has permeated into the thermoplastic transparent resin layer 22, and then the recording medium 20 is The toner image 15 is separated from the intermediate transfer body 6 together with the fixed toner image 15.

According to this method, as shown in FIG. 11B, the toner image 15 is embedded in the thermoplastic transparent resin layer 22, and the portion where there is no toner is the same as the portion where the toner is present. Since it is covered with the resin layer 22, it is possible to obtain a photographic color image having no difference in gloss due to the presence or absence of the toner.

On the other hand, as shown in FIG. 11C, a recording medium 10 having no thermoplastic transparent resin layer on its surface is used.
When the toner image 15 is transferred and fixed thereon, a difference in gloss occurs depending on the presence or absence of the toner, and a photographic color image cannot be obtained.

As described above, the thermoplastic transparent resin layer 2
In the method in which the toner image 15 is transferred and fixed on the recording medium 20 by the thermal transfer simultaneous fixing method using the recording medium 20 provided with the recording medium 2, it is possible to obtain a photographic color image having no gloss difference due to the presence or absence of toner. Becomes

However, when the toner image 15 is transferred and fixed at a high speed by this method, when the dot area ratio of the input image is about 50%, the toner image 15 is transferred to the thermoplastic transparent resin layer 22.
This makes it difficult to sink into the inside, causing uneven gloss and edge differences in the image, thereby deteriorating the image quality.

That is, in the above method, as shown in FIG. 12, heat is transmitted from the heating roll 8 to the toner image 15 and the thermoplastic transparent resin layer 22 through the intermediate transfer member 6,
As the transfer / fixing speed is increased, a sufficient amount of heat cannot be supplied to the toner image 15 and the thermoplastic transparent resin layer 22.

However, when the halftone dot area ratio of the input image is low, the amount of heat necessary for melting the toner image 15 may be small because the toner is originally small, and the thermoplastic transparent resin layer 22 may be in the middle due to the small amount of toner. Since it is easy to adhere to the transfer member 6, heat is easily transmitted directly from the intermediate transfer member 6 to the thermoplastic transparent resin layer 22, and the toner image 15 and the thermoplastic transparent resin layer 22 are easily melted.

Conversely, when the dot area ratio of the input image is high, the amount of toner is large and the air layer 16 between the toners is small, so that heat is easily transmitted in the toner spreading direction and the thermoplastic transparent resin Heat is easily transmitted to the layer 22, and the toner image 15 and the thermoplastic transparent resin layer 22 are also easily melted.

On the other hand, especially when the dot area ratio of the input image is about 50%, as shown in FIG. 12, since the toner is sparse and the air space 16 increases, the air space 16 is increased. Since the rate at which heat is transferred to the toner image 15 and the thermoplastic transparent resin layer 22 increases, and air has poor thermal conductivity, the toner image 15 and the thermoplastic transparent resin layer 22
Is reduced, the toner image 15 and the thermoplastic transparent resin layer 22 are less likely to be melted, and the toner image 15 is less likely to sink into the thermoplastic transparent resin layer 22.

At a portion where a step is generated in the toner pile height, for example, at a boundary portion between a solid portion and a white portion as shown as an edge portion 15e in FIG. At the stepped portion, the toner image 15 and the thermoplastic transparent resin layer 22
The toner image 15 does not sufficiently penetrate into the thermoplastic transparent resin layer 22 and an edge step occurs in the image.

If the heating temperature of the heating roll 8 is increased in accordance with the increase in the transfer / fixing speed in order to avoid such gloss unevenness and the edge difference of the image, only the toner is excessively melted. In addition, a hot offset that remains on the intermediate transfer member 6 without transferring and fixing the toner image 15 on the recording medium 20 occurs.

As described above, in the conventional electrophotographic system, the image on the recording medium is entirely uneven, the scattering of incident light is large, and the density gradation is relatively small like a human image. In the case of a large image, the image becomes a mixture of a high gloss area and a low gloss area, and the user feels strange.

Therefore, Japanese Patent Application Laid-Open No. Hei 7-248662 discloses that
The document density is converted into a toner adhesion amount, and specifically, 0.5 to 1.5 mg / cm ² so that the total amount of the toner adhesion including the adhesion amount of the transparent toner (transparent particles) becomes a certain value or more.
A method of spraying and fixing a transparent toner in addition to the color toner so as to be equal to or more than a certain value within the range described above is shown.

However, as described above, a method of transferring and fixing a toner image onto a recording medium by a simultaneous thermal transfer fixing method using a recording medium having a thermoplastic transparent resin layer on the surface is disclosed in Japanese Patent Application Laid-Open No. 7-248662. Is applied, a large amount of transparent toner is adhered to a white background (non-image part) in order to make the total amount of adhesion of the colored toner and the transparent toner equal to or more than a certain value, and a thermoplastic transparent resin layer is applied to the white background. In addition to the above, a large amount of transparent toner is present, which causes a problem that hot offset is likely to occur and a consumption amount of the transparent toner increases.

Accordingly, the present invention provides a color image using a colored toner and transparent particles on a recording medium having a thermoplastic transparent resin layer provided on a surface thereof by a special electrophotographic method which can be called a thermal transfer simultaneous fixing method. In an image forming apparatus for forming an image, and an image processing apparatus constituting an image processing unit of such an image forming apparatus, a high-quality photographic image having no gloss unevenness or edge steps regardless of a dot area ratio of an input image. A color image can be formed at high speed, hot offset can be prevented from occurring, and the consumption of transparent particles can be suppressed.

[0027]

An image processing apparatus according to the present invention converts an input color image signal from an image input device into an image recording signal of a plurality of colors for forming a toner image and a transparent particle image signal for forming a transparent particle image. An image processing apparatus for converting an image into an output color image signal to be sent to an image output apparatus, and particularly, a maximum halftone dot area ratio determined by characteristics of the image output apparatus, and an image of the plurality of colors. From the total of the dot area ratios of the recording signals, the dot area ratio of the transparent particle image is set to the maximum value when the difference between the two is a predetermined value, and the dot area of the transparent particle image when the difference between the two exceeds the predetermined value. The dot area ratio of the transparent particle image is determined so that the ratio is equal to or less than the maximum value.

In this case, the image processing apparatus includes color conversion means for converting an input color image signal into an image recording signal of a plurality of colors, and a halftone dot of a transparent particle image from the image recording signals of the plurality of colors from the color conversion means. A transparent particle image halftone dot area ratio determining means for determining an area ratio and generating a transparent particle image signal.

Further, the transparent particle image halftone dot area ratio determining means addresses the difference between the maximum halftone dot area ratio determined by the characteristics of the image output device and the total halftone dot area ratio of the image recording signals of a plurality of colors. It is desirable to have a look-up table for determining the dot area ratio of the transparent particle image.

Further, in this case, the transparent particle image halftone dot area ratio determining means obtains, from the image input device, an area information signal for distinguishing an image portion of the input image represented by the input color image signal from a white background portion. When the area information signal indicates a white background, the halftone dot area ratio of the transparent particle image can be set to zero regardless of the look-up table.

The image output device in each of the above cases is
The image carrier holding the toner image and the transparent particle image and the recording medium provided with a thermoplastic transparent resin layer on the surface are sandwiched and brought into close contact with each other, and the image carrier and the recording medium are heated and pressed in that state, After melting the toner image and the transparent particle image and the thermoplastic transparent resin layer, they are cooled or allowed to cool, and then the recording medium is separated from the image carrier together with the toner image and the transparent particle image.

The image forming apparatus of the present invention converts an input color image signal from an image input device into an output color image comprising a plurality of color image recording signals for forming a toner image and a transparent particle image signal for forming a transparent particle image. An image processing unit that converts the image into a signal, and an image output unit that forms a color image on a recording medium by an output color image signal from the image processing unit.In particular, the image processing unit includes: From the maximum dot area ratio determined by the characteristics of the image output unit and the total dot area ratio of the plurality of color image recording signals, the dot area ratio of the transparent particle image when the difference between the two is a predetermined value. Is the maximum value, and when the difference between the two exceeds a predetermined value, the dot area ratio of the transparent particle image is determined so that the dot area ratio of the transparent particle image is equal to or less than the maximum value, and the image output unit is , Toner image and transparent grain An image holding member holding an image and a recording medium provided with a thermoplastic transparent resin layer on its surface are sandwiched and brought into close contact with each other, and in this state, the image holding member and the recording medium are heated and pressed to form a toner image and transparent particles. After the image and the thermoplastic transparent resin layer are melted, they are cooled or allowed to cool, and then the recording medium is separated from the image carrier together with the toner image and the transparent particle image.

In this case, it is desirable to use, as the transparent particles for forming the transparent particle image, those having substantially the same optical characteristics and melting characteristics as the thermoplastic resin of the toner for forming the toner image.

The softening point of the thermoplastic transparent resin layer is -30 ° C. with respect to the softening point of the toner forming the toner image.
It is desirable to use a polyester-based resin having a temperature within the range of + 20 ° C.

It is desirable to use a recording medium in which the contact angle between the fused toner image and the transparent particle image and the thermoplastic transparent resin layer is 50 degrees or less.

Further, the thermoplastic transparent resin layer has a weight average molecular weight Mw in the range of 5,000 to 60,000, a number average molecular weight Mn in the range of 2,000 to 7000, and a ratio Mw / Mn of the two. It is desirable to be within the range of ~ 20.

[0037]

In the image processing apparatus or the image forming apparatus according to the present invention, the toner image and the image on the image holding member are filled in the image output device or the image output section so that the toner is filled with the transparent particles. A transparent particle image is formed, an image carrier holding the toner image and the transparent particle image and a recording medium having a surface provided with a thermoplastic transparent resin layer are sandwiched and adhered, and in that state, the image carrier and The recording medium is heated and pressed to melt the toner image and the transparent particle image and the thermoplastic transparent resin layer.

Therefore, even when the transfer and fixing of the toner image and the transparent particle image to the recording medium are performed at a high speed, and the dot area ratio of the input image is around 50%, it is not hindered by the air layer. A sufficient amount of heat is supplied to the toner image, the transparent particle image, and the thermoplastic transparent resin layer, and the toner image, the transparent particle image, and the thermoplastic transparent resin layer are reliably melted, and the toner image and the transparent particle image are heated. Since the resin sinks into the plastic transparent resin layer, uneven gloss and edge steps of an image do not occur.

Further, the dot area ratio of the transparent particle image is the difference between the maximum dot area ratio determined by the characteristics of the image output device or the image output unit and the total dot area ratio of the image recording signals of a plurality of colors. Is larger than or equal to the maximum value when the value exceeds a predetermined value, the development of the transparent particle image is suppressed or the transparent particle image is completely suppressed in a white background where the total dot area ratio of the image recording signals of a plurality of colors is zero. Since development is not performed, the occurrence of hot offset is prevented, and the consumption of transparent particles is suppressed.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] FIG. 1 shows an example of an image forming apparatus of the present invention equipped with an example of an image processing apparatus of the present invention.
00, an image processing device 200 and an image output device 300.

The image input device 100 takes in color images of various formats from the outside, and
8 bits for each color (red, green, blue)
It outputs RGB data of a total of 24 bits of 256 gradations.

Specifically, the image input device 100 is 35 m
m color negative film, positive film, or APS
A silver halide photographic film typified by a film
Read as RGB data by sensor or K
CD-ROM in ODAK / PhotoCD format
To read and convert the image data into RGB data, or capture the photographing data from a digital camera such as Canon DCS1c and convert it into RGB data, or edit the MO or Zi by using another computer by the user.
The color image data stored in a recording medium represented by p is read from the recording medium and converted into RGB data, or the image information transmitted from a device connected on a network is converted into RGB data,
Each has a function of transferring to the image processing apparatus 200.

The image processing apparatus 200 includes a color conversion unit 210
And the RGB data input from the image input device 100 are converted by the color conversion device 210 into YMCK (yellow, magenta, cyan,
(Black) is converted to data of four colors.

In the transparent particle image halftone dot area ratio determining means 220, the YMCK data from the color converting means 210 is
The dot area ratio of the transparent particle image is determined as described below,
T data, which is transparent particle image data, is generated, and YMCKT data obtained by adding YMCK data to the T data is sent to the image output device 300.

In the image output device 300, an image is formed on a recording medium having a surface provided with a thermoplastic transparent resin layer as described later, based on the YMCKT data output from the image processing device 200.

The input color image signal from the image input apparatus 100 is most generally RGB data, and the following example also shows the case of RGB data.
Data in another color space such as the YCC color space used in oCD may be used. Also, the color space of the image output device 300 is
The following example shows the case of the YMCK color space, but other color spaces such as the YMC color space and the RGB color space may be used.

As the color conversion means 210, for example, a means comprising a DLUT (direct look-up table) and an interpolation operation circuit is used in order to perform high-precision color conversion. In this case, the upper 4 bits of each of the 8 bits of RGB data from the image input device 100 provide R
The address of the lattice point near the point determined by the GB data is generated, and the YMCK data of the neighboring lattice point is read from the DLUT by the neighboring lattice point address, and the read lattice point data is used as the RGB data. Each of the lower four
Interpolation is performed by the bits to obtain output YMCK data.

For example, “Display and Imaging, SCI, Volume2, Number1 (199)
3) In P17 to P25, refer to the method of performing cubic interpolation with reference to the lattice points of eight neighboring points, the method of performing prism interpolation with reference to the lattice points of six neighboring points, and referencing the lattice points of four neighboring points. The method of performing tetrahedral interpolation is shown, and in this example,
Those methods, for example, a method of performing prism interpolation can be used. However, the neighboring grid point address need not be limited to the upper 4 bits.

The color conversion means 210 is not limited to the one comprising the DLUT and the interpolation arithmetic circuit as described above, but may be a matrix type color conversion circuit or a neural network type color conversion circuit which is generally widely used as the color conversion means. Other color conversion circuits may be used.

FIG. 2 shows an example of the image output device 300. In the case of a tandem engine type electrophotographic color printer of the above-mentioned thermal transfer simultaneous fixing type, the YMCKT data from the image processing device 200 is KYMCT data.
, Are converted by the screen generator 390 into a binary signal whose pulse width is modulated according to the data value, that is, a screen signal.

The laser diode 381 of the laser beam scanner 380 is driven by the screen signal from the screen generator 390, and the laser diode 3
From 81, a laser beam 1 is obtained.

The laser light modulated by the screen signal of each color of KYMCT (for convenience, “transparent” by the transparent particles is also one color) is applied to the photosensitive members 2K and 2K, respectively.
Raster irradiation is performed on 2Y, 2M, 2C, and 2T. Photoconductor 2
K, 2Y, 2M, 2C, and 2T are uniformly charged by scorotron chargers 3K, 3Y, 3M, 3C, and 3T, respectively, and are irradiated with laser light, so that their surfaces correspond to data of each color of KYMCT. An electrostatic latent image is formed.

The electrostatic latent images formed on the photoconductors 2K, 2Y, 2M, and 2C are developed into toner images by developing units 4K, 4Y, 4M, and 4C loaded with toners of respective colors KYMC. The electrostatic latent image formed on 2T is developed into a transparent particle image by a developing device 4T loaded with transparent particles.

The toner images and the transparent particle images of the respective colors KYMC are transferred from the photosensitive members 2K, 2Y, 2M, 2C and 2T to the belt-like intermediate transfer member 6 by the transfer units 5K, 5Y, 5M, 5C and 5T. Are sequentially transferred electrostatically.

The intermediate transfer body 6 is supported by rolls 7a and 7b and a heating roll 8, and circulates while moving in the direction of arrow 6a. A pressure roll 9 is disposed opposite to the heating roll 8, and the pressure roll 9 is attached to the recording medium tray 1.
As the recording medium is supplied from 1 to the recording medium supply device 12, the recording medium is pressed against the heating roll 8.

As shown in FIGS. 11A and 11B, the recording medium has a thermoplastic transparent resin layer formed on one surface of a base material such as paper, and the surface on which the thermoplastic transparent resin layer exists. Is inserted between the heating roll 8 and the pressure roll 9 so as to face the intermediate transfer member 6.

Then, the intermediate transfer body 6 holding the toner image and the transparent particle image of each color of KYMC and the recording medium are sandwiched between the heating roll 8 and the pressure roll 9 at a proper timing, and adhere to each other. While moving between the heating roll 8 and the pressing roll 9, it is heated and pressed.

As a result, the toner image and the transparent particle image on the intermediate transfer member 6 and the thermoplastic transparent resin layer on the surface of the recording medium are softened and melted, and the toner image and the transparent particle image are placed in the thermoplastic transparent resin layer. It penetrates and sinks.

Thereafter, the intermediate transfer member 6 and the recording medium are
It moves while being in close contact, and is cooled by the cooler 13. As a result, the toner image and the transparent particle image penetrating and sinking into the thermoplastic transparent resin layer on the surface of the recording medium are aggregated and solidified in the thermoplastic transparent resin layer, and have a strong adhesive force with the recording medium. And the toner image and the transparent particle image are fixed on the recording medium.

Thereafter, the recording medium on which the toner image and the transparent particle image are fixed is transferred from the intermediate transfer body 6 to the toner image and the transparent particle image at the position of the roll 7b having a small radius of curvature due to the stiffness of the recording medium itself. , And is discharged outside the image output device 300.

The intermediate transfer member 6 has a two-layer structure including a base layer and a surface layer. As the base layer, for example, a polyimide film having a thickness of 70 μm to which carbon black is added is used. In this case, the volume resistivity of the base layer is adjusted by adjusting the amount of carbon black added.

In addition, as the base layer, for example, a highly heat-resistant sheet having a thickness of 10 to 300 μm can be used, and polyester, polyethylene terephthalate, polyether sulfone, polyether ketone, polysulfone, polyimide, polyimide amide can be used. And a polymer sheet such as polyamide.

As the surface layer, for example, a silicon copolymer having a thickness of 50 μm is used. The silicon copolymer has a surface that is tacky to toner and transparent particles at room temperature, and further melts and fluidizes the toner and transparent particles to efficiently transfer the toner and transparent particles onto the recording medium. Since it has the property of easily releasing particles, it is most suitable for the surface layer.

In addition, as the surface layer, for example, a highly releasable resin layer having a thickness of 1 to 100 μm can be used. For example, tetrafluoroethylene, perfluoroalkyl vinyl ether copolymer, polytetrafluoroethylene Etc. can be used.

As the toner of each color of KYMC, a known toner composed of a thermoplastic binder containing a dye of each color can be used. In this example, the toner has a temperature-viscosity characteristic as shown in FIG. A polyester toner is used. This toner has a weight average molecular weight Mw of 54000, a melting temperature Tm of 120 ° C., and a viscosity η at the melting temperature Tm of 4000 P
as. The average particle size of the toner is, for example, 7 μm.

The above exposure or development conditions are set so that the amount of toner of each color on the recording medium is in the range of about 0.4 to 0.7 mg / cm ² depending on the content of the dye. . In this example, the toner amount of each color is 0.65 mg.
/ Cm ² .

Known transparent particles can be used. For example, (1) a homopolymer or copolymer of styrene or a derivative or substituted product thereof, such as styrene, vinyltoluene, α-methyltoluene, chlorostyrene, and aminostyrene; (2) methacrylic acid, methyl methacrylate, and ethyl methacrylate Such as methacrylic acid ester homopolymers or copolymers,
(3) homopolymers or copolymers of acrylates, such as acrylic acid, methyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate;
Dienes such as butadiene and isoprene, acrylonitrile or vinyl ethers, (5) homopolymers of vinyl monomers such as maleic anhydride, vinyl chloride and vinyl acetate, or copolymers with other monomers , (6) polyamide, (7) polyester, (8) polyurethane,
And the like can be used alone or as a mixture, but polyester is particularly preferred.

The polyester can be produced by reacting a polyhydric alcohol with a polybasic carboxylic acid.
Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol,
1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,
Diols such as 4-butanediol and cyclohexane dimethanol, bisphenol A alkylene oxide adducts such as hydrogenated bisphenol A and polyoxypropylene bisphenol A, and other dihydric alcohols can be used.

The polybasic carboxylic acids include, for example, maleic acid, fumaric acid, metaconic acid, citraconic acid, itaconic acid, terephthalic acid, isophthalic acid, cyclohexanedicarnbonic acid, succinic acid, acid anhydrides thereof, alkyls Esters and other dibasic carboxylic acids can be used. Further, conventionally known external additives can be used for the purpose of charge control and the like.

In this example, as the transparent particles, those having the same temperature-viscosity characteristics as the polyester toner having the temperature-viscosity characteristics shown in FIG. 3 are used. The average particle size of the transparent particles is, for example, 7 μm.

As the heating roll 8 and the pressure roll 9, a metal roll or a metal roll having a heat-resistant elastic layer such as silicon rubber on the surface thereof can be used. The heating temperature is set to about 120 to 240 ° C. so that the temperatures of the toner, the transparent particles, and the thermoplastic transparent resin layer in the heating and pressurizing section are equal to or higher than the respective melting temperatures. The pressure is set at about 3 to ²⁰ kg / cm ² .

The base material of the recording medium is not particularly limited, and may be a conventionally known acidic or neutral high-quality paper,
It is possible to use a medium paper, a waste paper, a recycled paper, a synthetic paper, and the like. The filler used for these does not need to be particularly limited, either.
Calcium carbonate such as heavy calcium carbonate, light calcium carbonate, chalk, and silicic acids such as kaolin, calcined clay, porphyrolite, sericite, talc,
An inorganic filler such as titanium dioxide or an organic pigment such as urea resin or styrene can be used. The sizing agent does not need to be particularly limited, and a sizing agent such as a rosin sizing agent, a synthetic sizing agent, a petroleum resin sizing agent, a neutral sizing agent, and a sizing agent such as a sulfate band and a cationized starch, and a fiber are used. Can be used in combination with the fixing agent. In addition, a paper strength enhancer, a dye, a pH adjuster, and the like may be added.

Further, the surface of the base material on which the thermoplastic transparent resin layer is provided is coated with a white pigment in order to reduce the irregular reflection component of the light incident on the thermoplastic transparent resin layer and obtain an image having good coloring. A layer may be provided.

Examples of the white pigment used for the white pigment coating layer include heavy calcium carbonate, light calcium carbonate, titanium dioxide, aluminum hydroxide, satin white, talc, calcium sulfate, barium sulfate, zinc oxide, magnesium oxide, and the like. Magnesium carbonate, amorphous silica, colloidal silica, white carbon, kaolin,
Mineral pigments such as calcined kaolin, delaminated kaolin, aluminosilicate, sericite, bentonite, smexite, and organic pigments such as polystyrene resin fine particles, urea folimarin resin fine particles, and fine hollow particles, are used alone or in combination. They can be used in combination.

As the resin for binding the white pigment,
A water-soluble adhesive, an emulsion, a latex, or the like can be used alone or as a mixture. For example, polyvinyl alcohol, modified polyvinyl alcohol, starches, gelatin, casein, methylcellulose, hydroxyethylcellulose, acrylamide-acrylate copolymer, acrylamide-acrylic acid-methacrylic acid terpolymer, styrene-acrylic resin , Isobutylene-maleic anhydride resin, water-soluble resin such as carboxymethylcellulose, acrylic emulsion,
A vinyl acetate emulsion, a vinylidene chloride emulsion, a polyester emulsion, a styrene-butadiene latex, an acrylonitrile-butadiene latex, or the like can be used.

[0076] Further, those obtained by finishing the coating surface by the casting method using the above-mentioned white pigment and casein are preferable because they have higher smoothness. In addition, a minute amount of a dye or a colored pigment may be added to the white pigment coating layer to adjust the color tone, and a fluorescent dye may be added to improve the visual whiteness. Further, various assistants such as a dispersant, an antifoaming agent, a plasticizer, a pH adjuster, a lubricant, a flow modifier, a solidification accelerator, a water resistance agent, and a sizing agent can be appropriately added as necessary.

When the recording medium is provided with the white pigment coating layer on the substrate as described above, the white pigment coating layer is formed on the white pigment coating layer.
When a white pigment coating layer is not provided, a thermoplastic transparent resin layer is provided directly on the substrate. It is desirable to use a polyester resin as the thermoplastic transparent resin layer.

The polyester resin can be produced by a reaction between a polyhydric alcohol and a polybasic carboxylic acid. Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol,
Diols such as 1,4-butanediol and cyclohexanedimethanol, bisphenol A such as hydrogenated bisphenol A and polyoxypropylene bisphenol A
Alkylene oxide adducts and other dihydric alcohols can be used, but bisphenol A alkylene oxide adducts such as polyoxypropylene-modified bisphenol A are particularly desirable.

The polybasic carboxylic acids include, for example, maleic acid, fumaric acid, metaconic acid, citraconic acid, itaconic acid, terephthalic acid, isophthalic acid, cyclohexanedicarnbonic acid, succinic acid, anhydrides of these acids, alkyls Esters and other dibasic carboxylic acids can be used.

Further, in order to adjust the surface electric resistance, sodium chloride, potassium chloride, potassium chloride,
Inorganic substances such as sodium sulfate, zinc oxide, titanium dioxide, tin oxide, aluminum oxide, and magnesium oxide, and organic materials such as alkyl phosphate ester salts, alkyl sulfate ester salts, sodium sulfonate salts, and quaternary ammonium salts, They may be blended alone or blended. Further, in order to adjust the friction coefficient of the recording medium or the like, styrene-based plastic particles or the like may be mixed in a minute amount that does not impair the image quality, or various surfactants may be applied.

The thickness of the thermoplastic transparent resin layer made of a polyester resin is preferably about 2 to 20 μm, particularly 4 to 20 μm.
A range of 15 μm is preferred. Below this range, the melted toner image and the transparent particle image cannot be embedded in the thermoplastic transparent resin layer and rise, and above this range, the offset phenomenon tends to occur.

As described above, the softening point of the polyester resin is preferably in the range of -30.degree. C. to + 20.degree. C., more preferably in the range of -20.degree.

The weight average molecular weight Mw of the polyester resin is
The number average molecular weight Mn ranges from 5,000 to 60,000
It is desirable that the ratio Mw / Mn of both ranges from 2 to 20. When the molecular weight and the molecular weight distribution exceed the upper limit of this range, the softening point of the thermoplastic transparent resin layer rises, and the sinking of the toner and the transparent particles becomes worse. May become too soft and cause an offset phenomenon.

[0084] The molecular weight of the polyester resin can be measured by gel permeation chromatography. For example, a fully automatic high-temperature high-speed chromatograph (Waters ALS / G manufactured by Waters) is used as a measuring device.
PC150C), tetrahydrofuran as a solvent, a flow rate of 1.0 ml / min, a temperature of 40 ° C., and a differential refractometer (RI) as a detector.

The sinking of the molten toner and the transparent particles into the recording medium also relates to the compatibility between the molten toner and the transparent particles and the thermoplastic transparent resin layer on the recording medium.
In order to check the compatibility, the contact angle between the molten toner and the molten transparent particles and the thermoplastic transparent resin layer was measured by the following method. However, in this example, since the toner and the transparent particles have the same melting characteristics as described above, the measurement was performed only for the toner.

(1) First, powder toner is filled into a concave tablet frame having a diameter of 13 mm and a height of 33 mm of a tablet press SSP-10 type tablet press manufactured by Shimadzu Corporation. Ton load is applied for 1 minute to form a toner disk. At this time, a standard disc has a diameter of 13 mm, a thickness of 1.2 mm, and a weight of 0.18 g.

(2) Next, the recording medium is placed on a hot plate, the toner disk is placed on the recording medium so as to be in contact with the thermoplastic transparent resin layer, and left at a set temperature for 90 seconds. After that, the recording medium and the toner disk are
The recording medium is placed on an aluminum plate that has been left in the air at a temperature of ° C., and is rapidly cooled. The set temperature is 10 ° C. higher than the softening point of the toner.

(3) Next, using a contact angle measuring device manufactured by Kyowa Interface Chemical Co., Ltd., the angle of the foot in contact with the thermoplastic transparent resin layer after the toner was solidified was rotated by 90 degrees. The measurement is made at four points, and the average value is defined as the toner contact angle.

The contact angle of the toner, that is, the contact angle of the thermoplastic transparent resin layer with the molten toner is preferably 50 degrees or less, particularly preferably 30 degrees or less. If the upper limit is exceeded, the sinking of the image becomes poor, causing uneven gloss or causing a phenomenon that the edge of the image appears to float. In the above example, the toner contact angle was 30 degrees or less.

The image output device 300 is not limited to the tandem engine type shown in FIG. 2, but may be a single engine type. Even with the single engine system, the above-described thermal transfer simultaneous fixing system can be adopted.

Further, without using the intermediate transfer member, the toner image and the transparent particle image of each color are developed on the belt photoreceptor, and the toner image and the transparent particle image of each color on the belt photoreceptor are directly thermoplastically transparent. The image can be transferred and fixed on the recording medium having the resin layer formed thereon by the simultaneous thermal transfer fixing method described above.

In the color conversion means 210 of the image processing apparatus 200, the input RG from the image input apparatus 100 is used as described above.
B data is converted to YMCK data. In this case,
As is well known, input RGB data is first converted to YMC data, and then the YMC data is converted to YMCK data by under color removal (UCR) and black plate generation.

That is, assuming that the rate of replacement with black (UCR rate) in undercolor removal and black plate generation is 50%, as shown in FIG. 4, the color with the lowest halftone dot area ratio among the three YMC colors (see FIG. 4). In the case of 4, an amount equivalent to 50% of Y) is replaced with black (K).

As is known, when the UCR rate is lowered, Y
If the toner consumption of each color of the MC increases and approaches 100%, on the other hand, the saturation decreases and the image lacks vividness.
Therefore, the UCR rate is generally set to 30 to 70%. In particular, considering that a photographic image is output, since the decrease in saturation is fatal, the UCR rate is set to 50% in this example. Hereinafter, the dot area ratio of the transparent particle image, which is the gist of the present invention, when the UCR rate is set to 50% will be discussed.

As shown in FIG. 5, the maximum halftone dot area ratio of the YMC data obtained by the color conversion means 210 from the RGB data input from the image input device 100 is 100%.
Assuming that the R rate is 50%, YMCK after generation of the undercolor removal black plate
The maximum value of the total dot area ratio of the data is 200%.
This is the maximum halftone dot area ratio determined by the characteristics of the image forming apparatus.

The halftone dot area ratio determining means 220 of the image processing apparatus 200 determines the maximum halftone dot area ratio M determined by the characteristics of the image forming apparatus and the color conversion means 21.
Difference A from 0 to total S of dot area ratio of YMCK data
The halftone dot area ratio of the transparent particle image is determined according to (= MS), and T data which is transparent particle image data is generated.

More specifically, the one-dimensional LUT (look-up table) is provided in the transparent particle image dot area ratio determining means 220.
The relationship between the above-mentioned difference A and the area ratio of the halftone dot area of the transparent particle image is described in advance. Then, the transparent particle image halftone dot area ratio determining means 220
The above difference A is calculated from the total dot area ratio S of the YMCK data from
The dot area ratio of the transparent particle image is read from T.

Here, the relationship between the dot area ratio of the transparent particle image and the difference A is, for example, as shown by the solid line 31 in FIG. 6, when the difference A is in the range of 0 to 100%. 0 to 100% so that the ratio becomes larger as the difference A becomes larger.
When the difference A is in the range of 100 to 200%,
The relationship is such that the dot area ratio of the transparent particle image changes in the range of 100 to 30% so that the larger the difference A, the smaller the dot area ratio.

Incidentally, the above-mentioned Japanese Patent Application Laid-Open No.
When the total amount of the toner adhering amount including the adhering amount of the transparent particles is made to be a constant value as in No. 2, as shown by a chain line 32 in FIG.
In the entire range of the total dot area ratio S of the data, the larger the difference A, that is, the smaller the total dot area ratio S of the YMCK data, the larger the dot area ratio of the transparent particle image.
In a white background where the total dot area ratio S of the MCK data is 0%, the dot area ratio of the transparent particle image is 100%.

The relationship between the halftone dot area ratio of the transparent particle image and the difference A as shown by the solid line 31 in FIG.
When the total dot area ratio S of the K data is 100%, the dot area ratio of the transparent particle image becomes the maximum 100%.

Therefore, even when the transfer and fixing of the toner image and the transparent particle image to the recording medium are performed at a high speed and the dot area ratio of the input image is about 50%, the image is not hindered by the air layer. A sufficient amount of heat is supplied to the toner image, the transparent particle image, and the thermoplastic transparent resin layer, and the toner image, the transparent particle image, and the thermoplastic transparent resin layer are reliably melted, and the toner image and the transparent particle image are heated. Since the resin sinks into the plastic transparent resin layer, uneven gloss and edge steps of an image do not occur.

Furthermore, in a white background where the total dot area ratio S of the YMCK data is 0%, the dot area ratio of the transparent particle image becomes sufficiently small, and the development of the transparent particle image is suppressed. While the occurrence of offset is prevented,
The consumption of transparent particles is reduced.

In the image output device 300 of the above example,
When toner or transparent particles having a weight of 0.3 to 1.3 mg / cm ² can be placed on a recording medium, and the dot area ratio of YMCK data and T data is 100%, 0.6
5 mg / cm ² of toner and transparent particles are formed on the recording medium.

However, as shown in FIG.
When a toner image and a transparent particle image are formed on 2Y, 2M, 2C, and 2T and transferred onto the intermediate transfer member 6, T
Only the conditions for creating a transparent particle image based on data can be different from the conditions for creating a toner image based on YMCK data,
The maximum transparent particle amount when the dot area ratio of the transparent particle image is 100% can be appropriately selected.

In the above-described example, the toner image was evaluated for sinking, edge step, and uneven gloss with the transfer speed of the intermediate transfer member 6 set to 160 mm / sec. The screen used vertical lines, and the number of lines was 200 lines. As a result, as shown in FIG. 7 as “in the case of the present invention”, even if the conveyance speed of the intermediate transfer body 6 is as high as 160 mm / sec, the dots and edges of the image remain in the thermoplastic transparent resin layer of the recording medium. A high-quality, photographic color image was obtained without sinking and uneven gloss.

By the way, "conventional (30 mm / sec)"
Means that the transport speed of the intermediate transfer body 6 is set to 30 without using transparent particles.
mm / sec, the image is formed as “conventional (160 m
m / sec) "is a case where an image was formed at a conveyance speed of the intermediate transfer body 6 of 160 mm / sec without using transparent particles.

As described above, according to this example, the coloring toner and the transparent particles are formed on a recording medium having a surface provided with a thermoplastic transparent resin layer by a special electrophotographic method which can be called a thermal transfer simultaneous fixing method. With the use of, regardless of the dot area ratio of the input image,
A high-quality, photographic color image can be formed at high speed, hot offset can be prevented, and the consumption of transparent particles can be suppressed.

[Second Embodiment] FIG. 8 shows another example of the image forming apparatus of the present invention, on which another example of the image processing apparatus of the present invention is mounted.

In this example, the image input device 100 uses an internal area discriminating section to discriminate an image portion and a white background portion of an input image represented by RGB data, and to process a 1-bit area information signal, for example, by image processing. Output to the device 200. The area determination unit is
A known configuration can be employed. For example, when data from a computer is received by a printer controller and image information is developed, an image portion and a white background portion can be distinguished.

In the image processing device 200, the area information signal is received by the transparent particle image halftone dot area ratio determining means 220, and as shown in FIG. The combined region is defined as a transparent particle image forming region 27, and the other region is defined as a white background portion 26. As shown below, the transparent particle image forming region 27 and the white background portion 26 The point area ratio is determined separately.

That is, also in this example, a one-dimensional LUT is provided, and the maximum dot area ratio M determined by the characteristics of the image forming apparatus and the dot area ratio of the YMCK data from the color conversion means 210 are provided in advance. In this example, the relationship between the dot area ratio of the transparent particle image and the difference A with respect to the difference A with respect to the total S is shown by a solid line 33 in FIG. Thus, the difference A is 0-100
%, The halftone dot area ratio of the transparent particle image changes in the range of 0 to 100% so that the larger the difference A is, the larger the difference A is in the range of 100 to 200%. Instead, the halftone dot area ratio of the transparent particle image is maintained at 100%.

Then, the transparent particle image halftone dot area ratio determining means 2
In the transparent particle image forming area 27, the difference A is calculated from the total dot area ratio S of the YMCK data from the color conversion means 210 from the area information signal, and the difference A is used as an address. The dot area ratio of the transparent particle image is read from the LUT, and the white background portion 26 does not rely on the LUT,
The dot area ratio of the transparent particle image is set to 0%.

Therefore, according to this second example, the first
As in the case of the above example, even when the transfer and fixing of the toner image and the transparent particle image to the recording medium are performed at a high speed, and the dot area ratio of the input image is about 50%, the hindrance by the air layer may occur. Without sufficient heat is supplied to the toner image and the transparent particle image and the thermoplastic transparent resin layer, the toner image and the transparent particle image and the thermoplastic transparent resin layer are reliably melted, and the toner image and the transparent particle image are formed. The first example is obtained because the ink is sunk into the thermoplastic transparent resin layer to prevent uneven gloss and edge steps of the image, and the halftone dot area ratio of the transparent particle image is 0% in the white background portion 26. It is possible to further reduce the consumption of transparent particles.

[0114]

As described above, according to the present invention, on a recording medium having a surface provided with a thermoplastic transparent resin layer, a colored toner and a color toner can be formed by a special electrophotographic method which can be called a simultaneous thermal transfer fixing method. Using transparent particles, it is possible to form high-quality, photographic color images without gloss unevenness and edge steps at high speed, regardless of the dot area ratio of the input image, and prevent hot offset from occurring. And the consumption of transparent particles can be suppressed.

When the halftone dot area ratio of the transparent particle image is determined by the look-up table as in the third aspect of the present invention, the halftone dot area ratio of the input image is controlled after suppressing the consumption of the transparent particles. Regardless of the above, the dot area ratio of the transparent particle image from which an image having no uneven gloss and no edge step can be obtained can be freely and easily set.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first example of an image processing apparatus or an image forming apparatus according to the present invention.

FIG. 2 is a diagram illustrating an example of an image output device.

FIG. 3 is a diagram illustrating a temperature-viscosity characteristic of an example of a toner to be used.

FIG. 4 is a diagram for explaining undercolor removal and black plate generation;

FIG. 5 is a diagram provided for describing a maximum halftone dot area ratio.

FIG. 6 is a diagram showing characteristics of a lookup table used in a transparent particle image halftone dot area ratio determining means of the first example.

FIG. 7 is a view showing an experimental result in a case according to the present invention.

FIG. 8 is a diagram illustrating a second example of the image processing apparatus or the image forming apparatus according to the present invention.

FIG. 9 is a diagram illustrating a relationship between an image portion and a white background portion and a transparent particle image forming region in a second example.

FIG. 10 is a diagram showing characteristics of a look-up table used for a transparent particle image dot area ratio determining means of the second example.

FIG. 11 is a diagram for explaining a recording medium provided with a thermoplastic transparent resin layer and a thermal transfer simultaneous fixing method.

FIG. 12 is a diagram provided to explain a case where an image is formed by a simultaneous thermal transfer fixing method on a recording medium provided with a thermoplastic transparent resin layer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 image input device 200 image processing device 210 color conversion means 220 transparent particle image dot area ratio determination means 300 image output device 2K, 2Y, 2M, 2C, 2T photoreceptor 3K, 3Y, 3M, 3C, 3T scorotron charger 4K , 4Y, 4M, 4C, 4T Developing device 5K, 5Y, 5M, 5C, 5T Transfer device 6 Intermediate transfer member 8 Heating roll 9 Pressure roll 11 Recording medium tray 13 Cooler 20 Recording medium 21 Substrate 22 Thermoplastic transparent resin layer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobuyuki Kato 430 Nakai-cho, Sakaigami-gun, Kanagawa Prefecture Green Tech Nakai Fuji Xerox Co., Ltd. In-house Stock Company (72) Inventor Masahiro Takamatsu 430, Nakai-cho, Ashigagami-gun, Kanagawa Prefecture Green Tech Nakai Fuji Xerox Co., Ltd. In-house (56) References JP-A-10-55089 (JP, A) JP-A-4-338984 (JP) JP-A-9-200551 (JP, A) JP-A-10-55085 (JP, A) JP-A-7-266614 (JP, A) JP-A-6-175461 (JP, A) 4-283756 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) G03G 13/01 G03G 15/01-15/01 117 G03G 15/00 303 H04N 1/46

Claims (10)

(57) [Claims] An input color image signal from an image input device is to be sent to an image output device comprising a plurality of color image recording signals for forming a toner image and a transparent particle image signal for forming a transparent particle image. An image processing apparatus that converts the image data into an output color image signal, comprising: a maximum halftone dot area ratio determined by characteristics of the image output device; When the difference is a predetermined value, the dot area ratio of the transparent particle image is set to the maximum value, and when the difference between the two exceeds the predetermined value, the dot area ratio of the transparent particle image is set to be equal to or less than the maximum value. An image processing apparatus for determining a dot area ratio. 2. An image processing apparatus according to claim 1, wherein said image processing apparatus converts said input color image signal into said plurality of color image recording signals, and a plurality of color conversion means. An image processing apparatus comprising: a transparent particle image halftone dot area ratio determining unit that determines a halftone dot area ratio of a transparent particle image from a color image recording signal to generate the transparent particle image signal. 3. The image processing apparatus according to claim 2, wherein said transparent particle image halftone dot area ratio determining means calculates a total of the maximum halftone dot area ratio and the halftone dot area ratios of the plurality of color image recording signals. An image processing apparatus having a look-up table for determining a dot area ratio of a transparent particle image using a difference between the two as an address. 4. The image processing apparatus according to claim 3, wherein said transparent particle image halftone dot area ratio determining means is configured to output, from the image input device, an image portion of an input image represented by the input color image signal and a white background. Image processing for obtaining a region information signal for discriminating a region and when the region information signal indicates a white background portion, the halftone dot area ratio of the transparent particle image is set to zero regardless of the lookup table. apparatus. 5. The image processing apparatus according to claim 1, wherein the image output device has an image carrier holding a toner image and a transparent particle image, and a thermoplastic transparent resin layer provided on a surface thereof. The recording medium is sandwiched and brought into close contact, the image carrier and the recording medium are heated and pressurized in that state, the toner image and the transparent particle image and the thermoplastic transparent resin layer are melted, and then cooled or cooled, Thereafter, the recording medium is separated from the image carrier together with the toner image and the transparent particle image. 6. An image processing for converting an input color image signal from an image input device into an output color image signal comprising a plurality of color image recording signals for forming a toner image and a transparent particle image signal for forming a transparent particle image. Unit, and an image output unit that forms a color image on a recording medium according to an output color image signal from the image processing unit, wherein the image processing unit has a maximum halftone dot determined by characteristics of the image output unit. From the area ratio and the total of the dot area ratios of the image recording signals of the plurality of colors, when the difference between the two is a predetermined value, the dot area ratio of the transparent particle image is set to the maximum value, and the difference between the two is a predetermined value. When exceeding, the dot area ratio of the transparent particle image is determined so that the dot area ratio of the transparent particle image is equal to or less than the maximum value.The image output unit includes an image holding member holding a toner image and a transparent particle image. A thermoplastic transparent resin layer is provided on the surface The image carrier and the recording medium are heated and pressurized in that state, and the toner image and the transparent particle image and the thermoplastic transparent resin layer are melted and then cooled or cooled. And an image forming apparatus for separating the recording medium from the image carrier together with the toner image and the transparent particle image. 7. The image forming apparatus according to claim 6, wherein the transparent particles forming the transparent particle image have substantially the same optical characteristics and melting characteristics as the thermoplastic resin of the toner forming the toner image. An image forming apparatus using: 8. The image forming apparatus according to claim 6, wherein the softening point of the thermoplastic transparent resin layer is -30 ° C. to + 20 ° C. with respect to the softening point of the toner forming the toner image.
An image forming apparatus comprising a polyester resin in the range of 9. The image forming apparatus according to claim 6, wherein the recording medium has a contact angle between the fused toner image and the transparent particle image and the thermoplastic transparent resin layer of 50 degrees or less. An image forming apparatus comprising: 10. The image forming apparatus according to claim 6, wherein the thermoplastic transparent resin layer has a weight average molecular weight Mw of 5,000.
660,000, and the number average molecular weight Mn is 2,000.
70007000, and the ratio Mw / Mn of both is 2２〜
20. An image forming apparatus, wherein the number falls within a range of 20.