JP4654980B2 - Image forming apparatus and image forming method - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and an image forming method employing an electrostatic recording method, and an image forming apparatus and an image forming apparatus using toner capable of developing different colors by exposing light of different wavelengths. It is about the method.

  2. Description of the Related Art Conventionally, in a recording apparatus that obtains a color image by an electrophotographic method, the basic three primary colors are developed according to each image information, and these toner images are sequentially superimposed to obtain a color image. As a specific apparatus configuration, a so-called four-cycle machine that obtains a color image by repeatedly developing each color on a photosensitive drum on which a latent image is formed by an image forming method and transferring them to a transfer member, Alternatively, a tandem machine or the like that includes a photosensitive drum and a developing device for each color image forming unit and transfers a toner image successively and sequentially to obtain a color image by moving a transfer member.

  These are at least common by having a plurality of developing devices for each color. For this reason, in normal color image formation, four developing devices in which black is added to the three primary colors are required, and in the tandem machine, four photosensitive drums are required for each of the four developing devices. An increase in the size and cost of the apparatus is inevitable, for example, a means for matching the synchronization of the forming means is required.

On the other hand, a method for obtaining a color image with a single developing device has been proposed (see, for example, Patent Documents 1 and 2). However, in these techniques, light is irradiated to give color development information to the developed toner image. Therefore, when the position of light irradiation is shifted, there is a problem that the latent image (high potential) in the immediate vicinity of the toner image is abruptly collapsed and the toner is scattered due to homopolar repulsion.
JP-A 63-131364 JP 2003-330228 A

The object of the present invention is to solve the above-mentioned problems of the prior art.
That is, according to the present invention, coloring information is imparted to a formed toner image by coloring the toner image, and coloring information is imparted to the toner image when a full-color image is formed with one developing device. To provide an image forming apparatus and an image forming method capable of preventing the occurrence of toner scattering and preventing high-quality image formation by preventing a rapid change in high potential difference even when there is an exposure misalignment. With the goal.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> An image forming apparatus using toner that is controlled so as to maintain a colored state or a non-colored state by providing coloring information by light,
An image carrier, a charging unit for charging the surface of the image carrier, an electrostatic latent image forming unit for forming an electrostatic latent image on the charged surface of the charged image carrier, and the toner A developing means for forming a toner image with a developer containing the color developing means, a coloring information providing means for providing coloring information by light to the toner image formed on the surface of the image carrier, and a toner image to which the coloring information is provided as a recording medium A transfer means for transferring to the surface; a fixing means for fixing the toner image transferred to the surface of the recording medium by heat and / or pressure; and a coloring means for coloring the toner image to which the coloring information is given by heating. Including
The image forming apparatus further includes a charge removing unit that is disposed downstream of the developing unit in the moving direction of the image carrier and lowers at least the potential near the toner image on the surface of the image carrier before the exposure by the color information providing unit. It is.

In the image forming apparatus, for example, a toner image is formed on the image carrier by the logical sum of image formation information of four colors of cyan (C), magenta (M), yellow (Y), and black (K), and then The toner image is exposed to light of a wavelength according to color information to give color development information to the toner image, and then the toner image to which color development information is given is transferred and fixed on a recording medium. At the same time, a color image of the toner is performed by heat, whereby a color image is obtained. Therefore, since a full color image can be obtained with one image carrier and one developing device, the apparatus can be greatly reduced in size.
In addition, since the surface potential in the vicinity of the toner image on the image carrier can be lowered in advance or simultaneously with the color information applying exposure by the charge removing means, the toner scattering without causing a sudden high potential difference change due to the color information providing exposure. Can be prevented.

<2> The image forming apparatus according to <1>, wherein the charge removing unit is a light discharging unit, and irradiation light from the light discharging unit has a wavelength range in which the toner image is not absorbed and only the image carrier is absorbed. It is.

  When using a light neutralizing means as the charge removing means, the wavelength range of the irradiated light is set to a wavelength range that is absorbed only by the image carrier without absorbing the toner image, so that light for coloring is imparted to the toner image. Therefore, the potential of the surface portion of the desired image carrier can be lowered.

<3> The image forming apparatus according to <1>, wherein the charge removing unit is a non-contact charging unit.

<4> The image forming apparatus according to <1>, wherein the charge removing unit is a contact charging unit.

  The charge removing means may be a non-contact charging means or a contact charging means. By applying a charge having a polarity opposite to the potential of the surface of the image carrier, the potential of the surface of the image carrier is similarly set. Can be reduced.

<5> The color information imparting unit exposes the toner image formed on the surface of the image carrier from the back side of the image carrier, and the color information is applied to the toner image by the light transmitted through the image carrier. The image forming apparatus according to <1>, wherein the image forming apparatus is a means for imparting.

  If the exposure to give color information to the image carrier is performed from the back side, in addition to the above effects, exposure means for giving color information can be installed inside the image carrier, so that the entire apparatus is made more compact. be able to.

<6> Reflecting means for reflecting the light for imparting color development information to the toner image transmitted through the image carrier, wherein the charge removing means is disposed opposite to the color development information provision means via the image carrier. The image forming apparatus according to <5>.

  As described above, if the color information imparting exposure is reflected and exposure light is applied to the toner image again, the upper portion of the toner image is sufficiently exposed to the color information at the same time as the charge removal by the charge removing means. Generation | occurrence | production can be avoided and color development can be improved.

<7> The image forming apparatus according to <1>, wherein the charge removing unit is disposed at the same position as an exposure position of the color information providing unit with respect to the image carrier.

<8> The image forming apparatus according to <1>, further including a light irradiation unit that irradiates light onto the surface of the recording medium after fixing.

  In the toner after coloring, the coloring reaction may be further continued. On the other hand, by irradiating with light, reactive substances remaining in the coloring portion that is controlled to be incapable of coloring can be decomposed or deactivated, and variation in color balance after image formation can be more reliably performed. It is possible to suppress the background color and to remove or bleach the background color.

<9> A photocurable composition comprising a first component and a second component that are present in a state where the toners are separated from each other and react with each other, and any one of the first component and the second component <1>, wherein the photocurable composition is maintained in a cured or uncured state by providing color development information by light, and the reaction for color development is controlled. An image forming apparatus.

As the toner in the present invention, as described above, for example, when color development information by light called a color development portion is given in a binder resin, it is possible to develop a specific color (or maintain a non-color development state). If a structure having one or more continuous regions (which is possible) is used, the light-receiving portion receives light, so that the light-receiving efficiency of one toner particle can be increased. However, it is used in the image forming apparatus of the present invention. As a result, a higher quality image can be obtained.
Furthermore, since the coloring information imparting mechanism is not a reversible reaction, it has the advantage that there is no time restriction until coloring by heating, so printing up to a low speed range is possible, that is, it can correspond to a wide speed range, Also, there is a merit that the arrangement place of the fixing device or the like where coloring is performed by heating has a high degree of freedom.

<10> An image forming method using a toner that is controlled so as to maintain a colored state or a non-colored state by providing coloring information by light,
A charging step for charging the surface of the image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the charged surface of the charged image carrier, and a toner containing the electrostatic latent image by a developer containing the toner. A developing step for forming an image, a coloring information providing step for imparting coloring information by light to the toner image formed on the surface of the image carrier, and a transfer step for transferring the toner image to which the coloring information is imparted to the surface of the recording medium And a fixing step of fixing the toner image transferred to the surface of the recording medium by heat and / or pressure, and a coloring step of coloring the toner image provided with the coloring information by heating,
Further, the image forming method further comprises a charge removing step for lowering the potential of at least the vicinity of the toner image on the surface of the image carrier before the exposure for providing the color development information on the downstream side in the moving direction of the image carrier from the developing step. is there.

  According to the present invention, coloring information is imparted to a formed toner image by coloring the toner image, and the coloring information is imparted to the toner image when a full-color image is formed with one developing device. To provide an image forming apparatus and an image forming method capable of preventing the occurrence of toner scattering and preventing high-quality image formation by preventing a rapid change in high potential difference even when there is an exposure misalignment. Can do.

Hereinafter, the present invention will be described in detail.
An image forming apparatus (image forming method) of the present invention is an image forming apparatus (image forming method) that uses toner that is controlled so as to maintain a colored state or a non-colored state by the provision of coloring information by light. An image carrier, a charging unit for charging the surface of the image carrier, an electrostatic latent image forming unit for forming an electrostatic latent image on the charged surface of the charged image carrier, and the toner A developing means for forming a toner image with a developer containing the color developing means, a coloring information providing means for providing coloring information by light to the toner image formed on the surface of the image carrier, and a toner image to which the coloring information is provided as a recording medium A transfer means for transferring to the surface; a fixing means for fixing the toner image transferred to the surface of the recording medium by heat and / or pressure; and a coloring means for coloring the toner image to which the coloring information is given by heating. Further including It is arranged from the image unit in the downstream side in the movement direction of the image bearing member, characterized by having a charge removing means for reducing at least in the vicinity of the toner image potential of the image bearing member surface prior to exposure by the color information imparting means.

  The toner used in the present invention has a function of maintaining a state in which, for example, when each toner particle is exposed to light of a different wavelength, the color is developed according to the wavelength, or the color is not developed (non-colored). is doing. That is, the toner has a chromogenic substance (and a color developing portion including this) that can develop color by providing color development information by light, and the toner can develop color or non-color by the application of color development information by light. It is controlled to maintain this state.

Here, the “applying color development information by light” refers to a desired region of a toner image in order to control the color development / non-color development state and the color tone upon color development in units of individual toner particles constituting the toner image. On the other hand, it means that one or more kinds of light having a specific wavelength are selectively given, or no light is given.
Further, the toner as described above is not particularly limited as long as it can exhibit the above functions, and examples thereof include the toner described in Patent Documents 1 and 2 and the toner preferably used in the present invention described later. Can do.

  In the image forming apparatus (image forming method) using the toner, such a toner is mounted on one developing device, and four types of cyan (C), magenta (M), yellow (Y), and black (K) are used. An electrostatic latent image is formed on the image carrier by the logical sum of the color image formation information, and the electrostatic latent image is developed with the toner to form a toner image. Thereafter, light having a wavelength corresponding to the color information is obtained. Then, the toner image is exposed to give color development information to the toner image. Thereafter, the toner image to which the coloring information is given is transferred to a recording medium, and then fixed to the recording medium by heat and pressure. At this time, the color reaction of the toner is performed by the heat, and a color image is obtained.

  Accordingly, since a full color image can be obtained with one image carrier and one developing device, the size of the main body of the image forming apparatus is as close as possible to that of a monochrome printer, and the apparatus can be miniaturized. Become. In addition, since it is not necessary to layer toner for each color when forming a toner image, unevenness of the image surface can be suppressed, the gloss of the image surface can be made uniform, and the toner can be colored with a pigment or the like. Since no agent is used, it is possible to obtain a silver salt-like image.

  However, in the case of the above apparatus configuration, since the coloring information is applied to the toner image at least after the toner image is formed on the image carrier, it is natural that the latent image formation point on the image carrier and the coloring information addition point are provided. Need to align. In this case, even if the position control of both is performed as will be described later, the positional deviation between the image information given during the latent image formation and the light irradiation may occur due to fluctuations in the drive system of the apparatus. The image was sometimes disturbed.

That is, for example, FIG. 5 shows a state in which color development information is applied by reversal development by an electrophotographic process. When there is the positional deviation, the intensity of exposure 64 for color development information application is as follows. Therefore, the charging potential V _{H of the} unexposed portion of the image carrier on the end side of the toner layer 62 subjected to the reversal development greatly decreases, the end portion of the toner layer 62 collapses as shown by the arrow, and the toner splatters ( Blur) may occur.

In the present invention, in order to reduce the surface potential of at least the vicinity of the toner image on the image carrier in advance or simultaneously with the color forming information imparting exposure, the image carrier on the downstream side in the moving direction of the image carrier of the developing means. Charge removal means for lowering the surface potential of the body is arranged, and by this charge removal means, at least the surface potential in the vicinity of the coloring information application point is lowered before the coloring information application exposure so as not to cause a sudden high potential difference change. It has been found that toner scattering can be prevented by doing so.
Here, the vicinity of the toner image refers to a region obtained by extending the outer edge of the toner image formed on the surface of the image carrier by about 0.5 mm.

As will be described later, as the charge removing means, there are those for irradiating the surface of the image carrier with light and those for imparting charges. These are the conventional pre-transfer exposure (PTL) and pre-transfer charging (PTC). Is completely different. That is, any of the above means is for improving the transfer efficiency, but the charge removing means in the present invention prevents the occurrence of toner scattering. In the pre-transfer exposure, since light in the absorption wavelength region of the photoconductor as an image carrier is irradiated, the toner image is usually exposed to the light. In the present invention, such a toner image should not be irradiated with light. The pre-transfer charging is for recharging the toner image and / or lowering the potential on the surface of the photoreceptor, but the charge removing means in the present invention is for lowering the charging potential on the surface of the photoreceptor.
Therefore, since the purpose of the charge removing means in the present invention is different from that of the pre-transfer exposure and the pre-transfer charging, the same structure cannot achieve the purpose, and the structure is not conventional as described later. It is unique.

  An image forming apparatus (image forming method) for forming a color image by an electrophotographic process using toner capable of controlling color development or non-color development according to color development information by light, to which the present invention is applied. This will be described in detail.

FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus of the present invention. An image forming apparatus shown in FIG. 1 includes a photoconductor (image carrier) 10 used in a normal electrophotographic process, a charging device (charging means) 12, an exposure device (exposure means) 14, a developing device (developing means) 16, a transfer device. An apparatus (transfer means) 18 and a fixing device (fixing means) 22 are provided. Further, in this apparatus, coloring information is applied from the back surface of the photosensitive member 10 to the charge removing device (charge removing unit) 17 on the downstream side of the developing device 16 in the rotation direction of the photosensitive member (arrow C) and the developed toner image. The fixing device 22 also serves as a coloring device (coloring means) for coloring the toner image. Further, a light irradiation device 24 (light irradiation means) for irradiating the recording medium 26 with light for fixing the color development of the toner is provided on the downstream side of the fixing device 22. Reference numeral 20 denotes a cleaner. In FIG. 1, the coloring information is given from the back surface of the photoconductor 10. However, the present invention is not limited to this mode, and the coloring information may be given from the front side of the photoconductor 10. .
Hereinafter, the configuration of the image forming apparatus of the present invention will be described along each step in image formation.

<Charging process>
In this step, first, the entire surface of the photoreceptor 10 is charged by the charging device 12.
As the photoreceptor 10, any known one can be used. For example, an inorganic photosensitive layer such as Se or a-Si, or a single or multilayer organic photosensitive layer is formed on a conductive substrate. In the case of a belt-shaped photoreceptor, a transparent resin such as PET or PC can be used as the substrate, and the thickness is determined by design matters such as the diameter and tension of the roll on which the belt-shaped photoreceptor is stretched, and is approximately 10 to 500 μm. Range. Other layer configurations are the same as in the drum.

  In the coloring information providing step, when exposure is performed from the back surface of the photoconductor 10 (inside the photoconductor) as shown in FIG. 1, a transparent photoconductor having the base as a transparent resin or the like can be used. . In the case of a transparent photoconductor, a material transparent to exposure light is used as the photoconductor substrate. For example, glass and plastic materials are used as the base material, and the thickness is about 0.1 to 5 mm. In addition, a transparent conductive layer is formed on the outer surface for electrode formation, but the base material itself may be subjected to a conductive treatment.

As the transparent conductive layer, a metal oxide such as ITO, SnO ₂ or the like, finely mixed with a binder resin and applied, or a conductive polymer such as polypyrrole can be used. The thickness is determined from the required conductivity and permeability, and is approximately in the range of 0.01 to 10 μm.
In addition, when not using a transparent photoconductor, base materials, such as metal cylindrical bodies, such as aluminum normally used, and a nickel seamless belt other than the above-mentioned transparent base | substrate can also be used.

Further, since the exposure for providing color information, which will be described later, is performed with a considerably stronger intensity than the exposure for forming a normal latent image (the amount of light energy used for providing color information is used in a normal electrophotographic process) The exposure amount to the photoconductor (approximately 1000 times the ² mJ / m ² ) is necessary), and the photoconductor 10 may be damaged. For example, the photosensitivity of the charge generation layer of the photoconductor 10 is 1/1000 of the conventional one. If so, there is no problem because it is balanced.
In addition, the thickness of the photosensitive layer is determined from an insulating property that can withstand a charged potential in consideration of the transparency and film thickness reduction with time, and is preferably in a range of approximately 5 to 50 μm.

  Further, when the color development information is applied from the surface side of the photoconductor 10, it is preferable that the surface of the photoconductor 10 has a function of preventing deterioration of the photoconductor 10 due to exposure for providing color development information. Specifically, a surface layer that transmits only the exposure light for forming a latent image and reflects the exposure light for providing color information (but transmits the exposure light for forming a latent image) on the surface of the photosensitive layer. It is effective to provide Examples of the surface layer include a dichroic mirror coat (reflection) and a sharp cut filter (absorption) in which a light absorbing material is dispersed.

  A known charging means can be used for charging the photoreceptor 10. In the case of the contact method, a roll, a brush, a magnetic brush, a blade, or the like can be used. In the case of non-contact, a corotron, a scorotron, or the like can be used. The charging means is not limited to these.

  Among these, a contact-type charger is preferably used because of its excellent charge compensation capability. In the contact charging method, the surface of the photosensitive member is charged by applying a voltage to a conductive member brought into contact with the surface of the photosensitive member. The shape of the conductive member may be any of a brush shape, a blade shape, a roll shape, and the like, but a roll-shaped member is particularly preferable. Usually, a roll-shaped member is comprised from the resistance layer, the elastic layer which supports them, and a core material from the outside. Furthermore, a protective layer can be provided outside the resistance layer as necessary.

As a method of charging the photosensitive member 10 using these conductive members, a voltage is applied to the conductive member, and the applied voltage is preferably a DC voltage or a DC voltage superimposed with an AC voltage. As a voltage range, in the case of charging only with direct current, an absolute value of positive or negative of a desired surface potential of about + 500V is preferable, and the value is in a range of 700 to 1500V. When the AC voltage is superimposed, the DC value is approximately the desired surface potential ± 50 V, the AC peak-to-peak voltage (Vpp) is 400 to 1800 V, preferably 800 to 1600 V, and the frequency of the AC voltage is 50 to 20000 Hz. The frequency is preferably 100 to 5000 Hz, and any of sine wave, square wave, and triangular wave can be used.
The charging potential is preferably set in the range of 150 to 700 V in absolute value of the potential.

<Electrostatic latent image forming process>
A known exposure device 14 can be used for forming the electrostatic latent image. As the exposure device 14, for example, a laser scanning system, an LED image bar system, analog exposure means, an ion flow control head, or the like can be used, and the surface of the photoconductor 10 is exposed as indicated by an arrow A in FIG. It is possible. In addition to this, new exposure means developed in the future can be used as long as the effects of the present invention are achieved.

  The wavelength of the light source is in the spectral sensitivity region of the photoconductor 10. Until now, the near-infrared having an oscillation wavelength near 780 nm as the wavelength of the semiconductor laser has been mainstream, but an oscillation wavelength laser in the 600 nm range and a laser having an oscillation wavelength near 400 to 450 nm can be used as a blue laser. . A surface-emitting laser light source capable of multi-beam output is also effective for color image formation.

  Exposure to the photoconductor 10 is performed as a logical sum of the image formation information of the four colors at a position where toner described later is developed in the case of reversal development, and at a position other than developing toner in the case of regular development. The exposure spot diameter is preferably in the range of 40 to 80 μm so that the resolution is in the range of 600 to 1200 dpi. As the exposure amount, it is preferable that the post-exposure potential is in the range of about 5 to 30% of the charging potential. However, when changing the toner development amount according to the gradation of the image, the exposure position The exposure amount may be changed according to the development amount every time.

<Development process>
A known developing device 16 can be used for developing the electrostatic latent image. As a development method, a two-component development method composed of fine particles and toner for carrying a toner called a carrier, or a one-component development method composed of only a toner, and further improvement of other characteristics in these development methods Any developing method in which other constituents may be added can be used.

  Further, depending on the developing method, any one of the developer that develops in contact or non-contact with the photoreceptor 10 or a combination thereof can be used. Furthermore, a hybrid development method combining the one-component development method and the two-component development method can also be used. In addition to this, a new developing means developed in the future can be used as long as the effect of the present invention is achieved.

As the toner contained in the developer, for example, a color developing portion (Y color forming portion) capable of developing color to Y color, a color developing portion capable of developing color to M color (M color forming portion), and a color developing portion capable of developing color to C color ( (C coloring portion) may be included in one toner particle, or the Y coloring portion, M coloring portion, and C coloring portion may be included separately for each toner.
The toner development amount (the amount of toner attached to the photoreceptor) varies depending on the image to be formed, but it is preferably in the range of 3.5 to 8.0 g / m ² in a solid image, and is preferably 4.0 to 6 More preferably, it is in the range of 0.0 g / m ² .

  In addition, in the formed toner image T, the light for providing coloring information to be described later must spread over the entire irradiated portion, and therefore it is preferable to keep the toner layer thickness below a certain level. Specifically, for example, in a solid image, the toner layer is preferably 3 layers or less, more preferably 2 layers or less. The toner layer thickness is a value obtained by measuring the thickness of the toner layer actually formed on the surface of the photoconductor 10 and dividing this by the number average particle diameter of the toner.

<Charge removal process>
In the present invention, after the developing step, the potential of the surface of the photoconductor 10 that has not been exposed at least in the electrostatic latent image forming step near the toner image is lowered. Specifically, the electric charge of the portion on the surface of the photoconductor 10 is removed by the charge removing device 17 to reduce the potential.
The charge removal region may be at least near the toner image, and may be the entire surface of the photoreceptor surface that passes through this process.

  The charge removing device 17 is a static eliminating lamp that neutralizes the surface of the photosensitive member, for example, a light neutralizing means that emits light at a predetermined wavelength such as an LED, EL (electroluminescence), or a fluorescent lamp; a photosensitizer such as corotron, scorotron, pin corotron Non-contact charging means applied with direct current or direct current superposition alternating current having a reverse polarity to the surface charge of the body 10; contact charging of rolls, brushes, blades, ionic conductive media disclosed in JP-A-7-325458, etc. Means; etc. can be used. Further, in the case of the contact charging unit, the upper layer of the toner image T that has been developed in multiple layers may be collected, and may also serve as a collecting unit that makes the toner image T substantially one layer.

  The light neutralizing device 17 has a wavelength range in which the toner image T does not absorb the irradiation light and only the photosensitive member 10 absorbs the irradiation light, and does not give light for color development to the toner image. This is an essential requirement in that the potential of the body surface portion can be lowered. Here, “does not absorb light” means that the transmittance (emitted light / incident light) is 80% or more, and “absorbs light” means that the transmittance is 20% or less. .

  As the wavelength range, for example, as will be described later, exposure wavelengths (wavelengths of light absorbed by the toner image) for imparting color development information to the toner image T are 405 nm, 532 nm, and 657 nm. When the wavelength range is about 720 to 830 nm, the peak wavelength of the irradiated light is preferably in the range of 750 to 810 nm, and more preferably in the range of 770 to 790 nm. In order to achieve exposure satisfying the above conditions, an LED that emits light at a wavelength other than that at which the toner absorbs light and at which the photosensitive member 10 absorbs light is used, or the light absorption wavelength region of the toner is cut. It is preferable to use a lamp having a filter to be used.

  In this case, the difference (absolute value) between the absorption peak wavelength of the toner and the peak wavelength of the irradiation light of the photostatic device is preferably 50 nm or more, and more preferably 100 nm or more. Further, the difference (absolute value) between the absorption peak wavelength of the photoconductor 10 and the peak wavelength of the irradiation light is preferably within 100 nm, and more preferably within 50 nm.

  As the charge removing means in the present invention, the toner image formed on the surface of the photosensitive member is not exposed to the problem that the toner image is exposed before coloring information is applied, or the toner image is disturbed by contact. It is preferable to use a non-contact charging means.

  The arrangement place of the charge removal device 17 is not particularly limited as long as the charge removal device 17 can remove the charge before exposure by the coloring information applying device 28 on the downstream side of the developing device 16 in the rotation direction of the photosensitive member. Here, “before exposure by the coloring information applying device 28” means both before the coloring information after the toner image development and at the same time as the coloring information.

Hereinafter, preferred embodiments including the arrangement of the charge removing means in the present invention will be described with reference to the drawings.
FIG. 2 is a schematic cross-sectional view showing an example of a state in which charge removal is performed using a corotron which is a non-contact charging means as the charge removal means. In the drawing, the exposure 56 for providing color information is performed from the back side of the photoconductor 52, and the corotron 50 is arranged to face the color information means (not shown) through the photoconductor 52. Further, the back plate surface of the corotron 50 is mirror-finished reflecting means, and as shown by arrows E and F in the figure, the coloring information providing exposure 50 that has passed through the toner image 54 is reflected by the reflecting means. .

  In the exposure from the back surface of the photoconductor 52, there is a case where the exposure light amount for providing color information is not sufficient due to the light absorption of the photoconductor 52. Therefore, if the color information imparting exposure 56 is reflected and the exposure light 56 is imparted again to the toner image as in the present embodiment, the color information imparting exposure is sufficiently performed on the upper portion of the toner image 54 simultaneously with the charge removal by the corotron 50. Therefore, occurrence of toner scattering can be avoided and color development can be improved. As shown in the figure, the corotron 50 is provided so as to face the coloring information applying exposure 56. However, since the charge application by the corotron 50 is performed with a spread toward the photoconductor 52, as described above. Even if it is arranged, the toner image 54 is not exposed for coloring information before the charge is removed by the corotron 50.

Further, in this embodiment, the corotron 50 that is a non-contact charging unit is used in FIG. 2, but a lamp that is a light neutralizing unit may be used instead of the corotron 50. In this case, for example, by providing a coating layer such as a half mirror on the lamp surface, light from the inside of the lamp can pass and light from the outside can be reflected. The information providing exposure 56 can be similarly reflected.
Note that the reflectance of the exposure light when the reflection means is provided is preferably 70% or more, and more preferably 80% or more.

FIG. 3 is a schematic cross-sectional view showing another example of a state where charge removal is performed using a corotron which is a non-contact charging means as the charge removal means. In the drawing, the corotron 58 is also opened on the back plate side (upper side in the drawing), and the exposure 60 for applying color information passes through the opened portion and the surface side (toner image forming side) of the photosensitive member 52 is provided. ) In this way, the charge removal means and the location at the color information application position are the same, so that the size can be reduced. Further, it is possible to easily exhaust gas such as ozone and nitrogen oxide generated in the corotron from the opened portion to the outside of the apparatus.
In the embodiment shown in FIG. 3, a lamp may be used as the charge removing means instead of the corotron.

The surface potential of the photosensitive member 52 is lowered by the charge removing means having the above configuration. The degree of the reduction is, for example, that the difference between V _H and V _L (V _H −V _L ) in FIG. 5 is 100%. When it does, it is preferable to make the electric potential after a fall into the range of 10 to 70%, and it is more preferable to set it as the range of 30 to 50%. If the potential after the decrease is less than 10%, blur due to toner image collapse due to toner homopolar repulsion as shown in FIG. 5 may occur before color information imparting exposure. If it exceeds 70%, the potential may not be sufficiently lowered, and blurring may occur in the same manner due to the color information providing exposure.

  Further, in order to achieve a potential decrease in the above range, the illuminance is obtained in the case of photostatic discharge from the photosensitivity, capacitance, volume resistance, etc. of the photoreceptor used, and in the case of non-contact charging means. The current value can be determined experimentally.

<Coloring information application process>
Next, as shown in FIG. 1, coloring information by light as indicated by arrow B is applied to the toner image T thus obtained from the back surface of the photoreceptor 10 by the coloring information applying device 28. Note that the position of the color information providing step shown in FIG. 1 is one example.

  The coloring information providing device 28 may be anything as long as the toner particles to be colored at that time can emit light having a wavelength for developing a specific color with a predetermined resolution and intensity. For example, an LED image bar, a laser ROS, or the like can be used. The irradiation spot diameter of the light irradiated on the toner image T is preferably adjusted so as to be in the range of 10 to 300 μm so that the resolution of the formed image is in the range of 100 to 2400 dpi. More preferably, it is in the range of ˜200 μm.

The wavelength of light used to maintain the colored or non-colored state is determined by the material design of the toner used. For example, when using a toner that develops color when irradiated with light of a specific wavelength (photochromic toner), yellow 405 nm light (referred to as λ _A light) for color development (Y color), 535 nm light (referred to as λ _B light) for cyan (C color) color development for magenta (M color) When irradiating, light of 657 nm (referred to as λ _C light) is irradiated to each desired position for color development.

When the secondary color is developed, the light is combined. When the red (R color) is developed, λ _A light and λ _B light are used. When the green (G color) is developed, λ _A light and When the λ _C light is colored blue (B color), the λ _B light and the λ _C light are respectively applied to the desired positions for color development. Further, when the black color (K color), which is the tertiary color, is developed, the λ _A light, λ _B light, and λ _C light are applied to the desired positions for color development.

On the other hand, in the case of a toner that maintains a non-colored state by irradiation with light of a specific wavelength (light non-colorable type toner), for example, to prevent yellow (Y color) from being colored, 405 nm light (λ _A light) , 535 nm light (λ _B light) to prevent magenta (M color) color development, and 657 nm light (λ _C light) color development to prevent cyan (C color) color development. Irradiate each desired position. Accordingly, λ _B light and λ _C light are generated when Y color is generated, λ _A light and λ _C light are generated when M color is generated, and λ _A light and λ _B light are generated when C color is generated. Each of the desired positions for color development is irradiated.

When the secondary color is developed, the light is combined. When the red (R color) is developed, λ _C light is emitted. When the green (G color) is developed, λ _B light is transformed into blue (B When a color is developed, λ _A light is irradiated to each desired position for the color development. Further, when black (K color) which is a tertiary color is developed, exposure is not performed at a desired position where the color is developed.

For the light from the coloring information applying device 28, a known image modulation method such as pulse width modulation, intensity modulation, or a combination of the two described above can be used as necessary. The exposure amount of light is preferably in the range of 0.05~0.8mJ / cm ^2, and more preferably in the range of 0.1~0.6mJ / cm ^2. Particularly with respect to the exposure amount, exposure required amount is correlated with the amount of toner developed, for example, 0.2～0.4MJ the toner developing amount (solid) of about 5.5g / ^{m 2} / ^{m 2} It is preferable to perform exposure within the above range.

  When the exposure light at this time is a laser beam, the laser beam is incident on the photosensitive member, usually tilted several degrees (4 to 13 degrees) in order to prevent return light to the monitor (Photo Detector) in the laser. Although it is necessary, in the color information imparting exposure according to the present invention, since the return light is absorbed by the toner, the return light is extremely reduced and can be incident at an arbitrary angle including 0 degrees.

Hereinafter, it will be briefly described at what timing and for what position control the exposure for giving the coloring information is performed.
FIG. 4 is a specific circuit block diagram of the print control unit in the image forming apparatus of the present invention. In the figure, the printer controller 36 includes an OR circuit 40, an oscillation circuit 42, a magenta color control circuit 44M, a cyan color control circuit 44C, a yellow color control circuit 44Y, and a black color control circuit 44K. On the other hand, the exposure unit 38 is composed of an optical writing head 32 and a coloring information applying exposure head 34.

  Image data obtained by converting input RGB signals into CMYK values by an interface (I / F) (not shown) is further transmitted from the interface (I / F) to magenta (M), cyan (C), yellow (Y), and black. The pixel data (K) is output to the OR circuit 40. Here, the logical sum circuit 40 calculates the logical sum of CMYK and outputs it to the optical writing head 32.

  That is, logical sum data including all CMYK pixel data is output to the optical writing head 32, and optical writing is performed on the photosensitive member 10 as described above. Therefore, an electrostatic latent image based on logical sum data including all CMYK pixel data is formed on the peripheral surface of the photoreceptor 10.

  The CMYK pixel data is also supplied to the corresponding magenta color control circuit 44M to black color control circuit 44K, and the color information providing exposure head is synchronized with the oscillation signals fm, fc, fy, and fk output from the oscillation circuit 42. 34. That is, color data corresponding to each of magenta (M), cyan (C), yellow (Y), and black (K) is supplied to the color information providing exposure head 34, and the toner image T developed on the photoreceptor 10 is developed. Corresponding to the above, light of a specific wavelength for maintaining a colored or non-colored state is irradiated. Therefore, a photocuring reaction, which will be described later, occurs in the toner that has received the irradiated light, and color development information is given.

For example, color signal fm outputted from the magenta coloring control circuit 44M irradiates the lambda _B light in the color of the toner to the toner in a state capable of color development of magenta (M) color. In addition, the color development signal fc output from the cyan color development control circuit 44C irradiates the color development portion in the toner with the λ _C light, and makes the toner capable of developing cyan (C) color. Further, the same applies to yellow (Y) and black (K), and the color signals fy and fk output from the yellow color control circuit 44Y and the black color control circuit 44K are transmitted to the color development portion in the toner by the λ _A light or Irradiation with λ _A light, λ _B light, and λ _C light enables a yellow (Y) or black (K) color.

  As described above, the mechanism for forming a full color image has been described with respect to the color information providing step (means) in the present invention. However, the color information providing step in the present invention is a monochromatic color that produces one of yellow, magenta, and cyan. It may be a color information providing step for forming a color image. In this case, only the light of a specific wavelength corresponding to the desired color development among the yellow, magenta and cyan is emitted from the color development information imparting exposure head 34. Other preferable conditions and the like are the same as those at the time of full-color image formation.

<Transfer process>
The toner to which the color development information is given is then transferred to the recording medium 26 at a time. A known transfer device 18 can be used for transfer. For example, rolls, brushes, blades, and the like can be used for the contact method, and corotron, scorotron, pin corotron, and the like can be used for the non-contact method. Also, transfer by pressure or pressure and heat is possible.

  The transfer bias is preferably in the range of 300 to 1000 V (absolute value), and alternating current (Vpp: 400 V to 4 kV, 400 to 3 kHz) may be superimposed.

<Fixing process and coloring process>
The toner image in a state where it can be colored (or maintained in a non-colored state) is colored as described above when the recording medium 26 is heated by the fixing device 22. A known fixing means can be used as the fixing device 22. For example, a roll or a belt can be selected as the heating member and the pressure member, and a halogen lamp, IH, or the like can be used as the heat source. The arrangement can also correspond to various paper paths, for example, a straight path, a rear C path, a front C path, an S path, a side C path, and the like.

  In the present embodiment, the fixing device 22 serves as both a coloring process and a fixing process, but the coloring process may be provided separately from the fixing process. There is no particular limitation on the position where the color developing device for performing the color developing step is arranged.

  As the color development method, various methods can be considered according to the color development mechanism of the toner particles. Therefore, as the color development device (color development means), for example, the color development-related substance is cured in the toner using light of a different wavelength. Alternatively, a light emitting device that emits specific light by a method such as photolysis or a method that restricts the color, or a pressure device that causes a color to be developed or restricted by a method such as destroying colored particles encapsulated by pressurization. , Etc. can be used.

  However, these chemical reactions that cause color development generally have a slow reaction rate due to migration and diffusion, so it is necessary to give sufficient diffusion energy to any of the above methods. It can be said that the method of promoting the reaction is the best. For this reason, it is preferable to use a fixing device 22 that serves as both the color developing step and the fixing step.

<Other processes>
In this invention, it is preferable to include the light irradiation process which irradiates light to the image obtained through the fixing and coloring process. This makes it possible to decompose or deactivate the reactive substances remaining in the color-development part that has been controlled to be incapable of color development. Can be removed and bleached.
In this embodiment, the light irradiation step is provided after the fixing step. However, in the case of a fixing method that does not heat and melt, for example, pressure fixing in which fixing is performed using pressure, the fixing step is performed after the light irradiation step. Can also be done.

  The light irradiation device 24 is not particularly limited as long as the color development of the toner can be prevented from proceeding further, and a known lamp such as a fluorescent lamp, LED, EL, or the like can be used. Further, the wavelength includes three wavelengths in the light for coloring the toner, the illuminance is preferably in the range of 2000 to 200000 lux, and the exposure time is preferably in the range of 0.5 to 60 sec.

  In addition to these, the above-described image forming method may include a known process used in an electrophotographic process performed using a colorant such as a conventional pigment, for example, after transferring a toner image. A cleaning step for cleaning the surface of the image carrier may be included. As the cleaner 20, a known one can be used, and a blade, a brush, or the like can be used. A so-called cleaner-less process in which the cleaner 20 is removed is also applicable.

  In addition, the transfer process includes a first transfer process in which a toner image is transferred from an image carrier to an intermediate transfer body such as an intermediate transfer belt, and the toner image transferred onto the intermediate transfer body is used as a recording medium. An intermediate transfer method including a second transfer step for transferring may be used.

<Toner to be used>
Next, the toner used in the present invention will be described.
As described above, the toner used in the present invention is a toner that is controlled so as to be able to maintain a colored state or a non-colored state by applying coloring information by light. “Maintaining a colored or non-colored state” is also as described above.

  There are various types of toner having the above functions. For example, the toner disclosed in Patent Document 2 is a plurality of microcapsules having a capsule wall whose substance permeability is changed by an external stimulus. Are dispersed and mixed in a toner resin, and one of two kinds of reactive substances (color dye precursors) mixed with each other to cause a color reaction is contained in the microcapsule and the other. (Developer) is contained in the toner resin outside the microcapsule.

This toner uses a photoisomerized substance that increases the substance permeability when irradiated with light of a specific wavelength as the capsule wall, and when applying light irradiation or ultrasonic waves using this cis-trans transition, Two kinds of reactive substances existing inside and outside the capsule react to develop color.
Therefore, in such a toner, a large amount of the microcapsules cannot be present in the toner, and these may be unevenly distributed. Therefore, there are cases where the microcapsules cannot sufficiently receive light when used in the present invention. is there.

For this reason, in the present invention, a photocurable composition comprising a first component and a second component that exist in a state of being separated from each other and that develop color when reacted with each other, and any one of the first component and the second component And the photocurable composition is maintained in a cured or uncured state by the application of color development information by light, and the reaction for color development is controlled (hereinafter referred to as “F toner”). In some cases).
In this case, since the shape factor of the F toner can be controlled, it can be spherical to obtain high transfer efficiency. In such a case, it can be said that the aforementioned blur is likely to occur. Therefore, the use of the F toner in the present invention is a preferable combination for obtaining a high-quality image having high color developability and no blurring.

The color development mechanism and simple configuration of the toner will be described below.
As will be described later, the F toner can be colored in one specific color (or can maintain a non-colored state) when color development information by light called a color development portion is imparted to the binder resin. ) It has one or more continuous areas.
FIG. 6 is a schematic view showing an example of the color developing portion in the F toner. FIG. 6A is a cross-sectional view of one color developing portion, and FIG. 6B is an enlarged view of the color developing portion.

  As shown in FIG. 6 (A), the color forming portion 80 is composed of color-forming microcapsules 70 containing color formers of the respective colors and a composition 78 surrounding the color-forming microcapsules 70, as shown in FIG. 6 (B). The composition 78 is photopolymerized with a developer monomer (second component) 74 having a polymerizable functional group that develops color by approaching or contacting the color former (first component) 72 contained in the microcapsule 70. And an initiator 76.

  As the color former 72 encapsulated in the color developable microcapsules 70 in the color developing portion 80 constituting the toner particles, a triaryl leuco compound having excellent color hue is suitable. As the developer monomer 74 for coloring the leuco compound (electron donating property), an electron accepting compound is preferable. In particular, phenolic compounds are common, and can be appropriately selected from color developers used for heat-sensitive and pressure-sensitive paper. The color former develops color by an acid-base reaction between the electron-donating color former 72 and the electron-accepting developer monomer 74.

As the photopolymerization initiator 76, a spectral sensitizing dye that generates a polymerizable radical that is exposed to visible light and serves as a trigger for polymerizing the developer monomer 74 is used. For example, a reaction accelerator of the photopolymerization initiator 76 is used so that the color developing monomer 74 can cause a sufficient polymerization reaction for the three primary color exposures such as R color, G color, and B color. For example, by using an ion complex composed of a spectral sensitizing dye (cation) that absorbs exposure light and a boron compound (anion), the spectral sensitizing dye is photoexcited by exposure and electron transfer to the boron compound causes a polymerizable radical to be generated. To initiate polymerization.
By combining these materials, a color recording sensitivity of about 0.1 to 0.2 mJ / cm ² can be obtained as the photosensitive color developing portion 80.

  Depending on the presence or absence of light irradiation for color forming information on the color forming portion 80 having the above-described configuration, some of the color forming portion 80 has a polymer developer compound that is polymerized and a developer monomer 74 that is not polymerized. . In the color development unit 80 having the developer monomer 74 that has not been polymerized by a subsequent color development device such as heating, the developer monomer 74 migrates due to heat or the like, and migrates through the pores of the partition walls of the color developer microcapsules 70. Passes through and diffuses into the color former microcapsules. The developer monomer 74 and the color former 72 diffused in the microcapsule 70 are, as described above, the color former 72 is basic and the color developer 72 is acid-base as the developer monomer 74 is acidic. The reaction will cause color development.

  On the other hand, the developer compound that has undergone the polymerization reaction cannot diffusely pass through the pores of the partition walls of the microcapsule 70 due to the bulk due to the polymerization in the subsequent color development step by heating or the like, and the color developer 72 in the color development microcapsule. Color cannot be developed because it cannot react. Therefore, the chromogenic microcapsule 70 remains colorless. That is, the color developing portion 80 irradiated with the specific wavelength light is present without being colored.

  After color development, the entire surface is exposed again with a white light source at an appropriate stage to polymerize all remaining undeveloped color developing monomer 74 to achieve stable image fixing, and residual spectral sensitizing dye. The ground color is erased by disassembling. Note that the spectral sensitizing dye of the photopolymerization initiator 76 corresponding to the visible light region remains as a ground color until the end. Color phenomenon can be used. In other words, a polymerizable radical is generated by electron transfer from a photoexcited spectral sensitizing dye to a boron compound. This radical causes polymerization of the monomer, while reacting with the excited dye radical to cause color separation of the dye. As a result, the pigment can be decolored.

In the F toner, the color developing portions 80 (for example, Y color, M color, and C color) that perform such different color development are used as color developing agents other than the color developing agent 72 intended by each developer monomer 74. And can be used as one microcapsule in a state where they do not interfere with each other (in a state where they are isolated from each other). In this F toner, the space other than the microcapsules containing the electron-donating color former is filled with the electron-accepting developer and the photocurable composition, and the color-developing portion constituted thereby receives the light. The light receiving efficiency of the toner particles is overwhelmingly higher than that of the toner disclosed in Patent Document 2. Therefore, the effect of the back exposure can be fully utilized as compared with other toners.
In addition, as described above, the coloring information imparting mechanism is not a reversible reaction, and as a result, there is no time restriction until color development by heating. As a result, printing up to a low speed range is possible, that is, it is compatible with a wide speed range. In addition, there is also a merit that the degree of freedom is high with respect to the arrangement place of the fixing device or the like where coloring is performed by heating.

The configuration of the F toner will be further described in detail.
The F toner includes a first component and a second component that exist in a state of being separated from each other as colorable substances (coloring substances) and that develop colors when they react with each other. As described above, color development is facilitated by color development utilizing the reaction of two types of reactive components. The first component and the second component may be pre-colored in a state before color development, but are particularly preferably substantially colorless substances.

In order to facilitate the color development control, two types of reactive components that develop color when reacting with each other are used as the color developing materials. However, these reactive components do not diffuse the substance even when the color development information by light is not given. If they exist in the same easy matrix, spontaneous color development may progress during storage or manufacture of the toner.
For this reason, it is necessary that the reactive component be contained in different matrices (separated from each other) that are difficult to diffuse into each other region unless coloring information is given. is there.

  Thus, in order to inhibit the material diffusion in the state where the color development information by light is not given and prevent spontaneous color development at the time of storage or production of the toner, the first component of the two types of reactive components is Contained in the first matrix, the second component is contained outside the first matrix (second matrix), and between the first matrix and the second matrix, there is diffusion of the substance between the two matrices. When an external stimulus such as heat is applied, a partition wall having a function that enables diffusion of substances between both matrices according to the kind, strength, and combination of the stimulus is provided. Is preferred.

In order to arrange two types of reactive components in the toner using such a partition wall, it is preferable to use microcapsules.
In this case, the F toner preferably includes, for example, the first component of the two types of reactive components inside the microcapsule and the second component outside the microcapsule. In this case, the inside of the microcapsule corresponds to the first matrix and the outside of the microcapsule corresponds to the second matrix.

  This microcapsule has a core part and an outer shell covering the core part, and inhibits diffusion of substances inside and outside the microcapsule and external stimulus as long as external stimulus such as heat is not given. In this case, there is no particular limitation as long as it has a function that enables diffusion of substances inside and outside the microcapsule according to the type, strength, and combination of the stimulus. The core part contains at least one of the reactive components.

In addition, the microcapsule may be capable of diffusing substances inside and outside the microcapsule by applying light irradiation or a stimulus such as pressure, but the substance can be diffused inside and outside the microcapsule by heat treatment (outer shell substance). Particularly preferred are thermoresponsive microcapsules (which increase permeability).
In addition, the substance diffusion inside and outside the microcapsule when a stimulus is applied, from the viewpoint of suppressing a decrease in color density during image formation or suppressing a change in color balance of an image left in a high temperature environment, It is preferably irreversible. Therefore, the outer shell of the microcapsule irreversibly increases its substance permeability due to softening, decomposition, dissolution (compatibility with surrounding members), deformation, etc. by applying heat treatment, light irradiation and other stimuli. It is preferable to have the function of

Next, a preferable configuration when the F toner includes microcapsules will be described.
Such a toner preferably includes a first component and a second component that develop color when they react with each other, a microcapsule, and a photocurable composition in which the second component is dispersed. Examples of the toner include the following three modes.

That is, the F toner includes a first component and a second component that develop color when they react with each other, a photocurable composition, and microcapsules dispersed in the photocurable composition, and the first component is A mode (first mode) in which the second component is contained in the microcapsule and contained in the photocurable composition, a first component and a second component that develop color when reacted with each other, and a photocurable composition A mode in which the first component is included outside the microcapsule and the second component is included in the photocurable composition (second mode), or the first component that develops color when reacted with each other And a second component, one microcapsule containing the first component, and another microcapsule containing a photocurable composition in which the second component is dispersed (third embodiment). It is preferable.
Among these three modes, the first mode is particularly preferable from the viewpoints of stability before giving color development information by light, control of color development, and the like. In the following description of the toner, the toner will be described in more detail on the premise of the toner of the first aspect. However, the configuration, material, manufacturing method, etc. of the toner of the first aspect described below are the same as those of the second aspect. Of course, the toner of the third aspect and the third aspect can also be used / reused.

In addition, it is particularly preferable that the F toner using a combination of the above-described thermoresponsive microcapsule and the photocurable composition is one of the following two types.
(1) Even if the photocurable composition is heat-treated in an uncured state, the material diffusion of the second component contained in the uncured photocurable composition is suppressed, and light is emitted by irradiation with the color forming information providing light. When the heat treatment is performed after the curable composition is cured, a toner of a type that promotes material diffusion of the second component contained in the cured photocurable composition (hereinafter, referred to as “photochromic toner”). is there).
(2) When the photocurable composition is heat-treated in an uncured state (a state where the second component is not polymerized), the material diffusion of the second component contained in the uncured photocurable composition is promoted. When the photocurable composition is cured by irradiation with the color forming information imparting light (after the second component is polymerized), the material diffusion of the second component contained in the cured photocurable composition is caused. The type of toner to be suppressed (hereinafter sometimes referred to as “light non-color developing toner”).

The main difference between the photochromic toner and the non-photochromic toner is in the material constituting the photocurable composition. In the photochromic toner, the photocurable toner has no photopolymerizability. ) Whereas the second component and the photopolymerizable compound are at least included, the photo-non-colorable toner includes at least the second component having a photopolymerizable group in the molecule in the photocurable composition. .
The photocurable composition used in the photochromic toner and the non-photochromic toner preferably contains a photopolymerization initiator, and various other materials are contained as necessary. May be.

  As the photopolymerizable compound and the second component used in the photochromic toner, the interaction between the photocurable composition and the second component in the photocurable composition works in an uncured state. In the photocurable composition, the substance diffusion is suppressed, and the interaction between the two decreases in the state after curing of the photocurable composition (polymerization of the photopolymerizable compound) by irradiation with the color forming information imparting light. A material that facilitates diffusion of the second component is used.

Therefore, in the photochromic toner, before the heat treatment (coloring step), the coloration information imparting light having a wavelength for curing the photocurable composition is irradiated in advance, so that the first color contained in the photocurable composition. The two-component material diffusion becomes easy. Therefore, when the heat treatment is performed, a reaction (coloring reaction) between the first component in the microcapsule and the second component in the photocurable composition occurs due to dissolution of the outer shell of the microcapsule or the like.
On the contrary, the second component is trapped in the photopolymerizable compound even if it is heat-treated without irradiating the color-forming information imparting light having a wavelength for curing the photocurable composition, and comes into contact with the first component in the microcapsule. The reaction between the first component and the second component (coloring reaction) does not occur.

  As described above, in the photochromic toner, the first component and the second component are applied by combining the presence / absence of irradiation with color forming information providing light having a wavelength for curing the photocurable composition and the heat treatment. Can control the color development of the toner.

Further, in the non-photochromic toner, since the second component itself has photopolymerization property, even when irradiated with the color forming information imparting light, the wavelength of this light is not the wavelength that cures the photocurable composition, Since the second component contained in the photocurable composition can be easily diffused, if the heat treatment is performed in this state, the first component in the microcapsule and the photocurable composition are dissolved by dissolution of the outer shell of the microcapsule. Reaction (coloring reaction) with the second component in the composition occurs.
On the contrary, when the coloring information imparting light having a wavelength for curing the photocurable composition is irradiated before the heat treatment, the second components contained in the photocurable composition are polymerized with each other. The material diffusion of the second component contained in the composition becomes difficult. Therefore, the second component cannot be brought into contact with the first component in the microcapsule even when the heat treatment is performed, and the reaction (coloring reaction) between the first component and the second component does not occur.

  As described above, in the non-photochromic toner, the first component and the second component can be applied by combining the heat treatment with the presence / absence of irradiation with color forming information providing light having a wavelength for curing the photocurable composition. Since the reaction (coloring reaction) with the components can be controlled, the color development of the toner can be controlled.

Next, a preferable structure of the F toner will be described in more detail when the toner includes the photocurable composition and microcapsules dispersed in the photocurable composition.
In this case, the toner may have only one color developing portion including a photocurable composition and microcapsules dispersed in the photocurable composition, but preferably has two or more. Here, the “coloring part” means a continuous region that can develop a specific color when an external stimulus is applied as described above.
When the toner includes two or more coloring portions, only one type of coloring portion that can develop the same color may be included in the toner, but two or more types of coloring that can develop colors different from each other may be included. It is particularly preferable that the part is contained in the toner. This is because the color that can be developed by one toner particle is limited to only one type in the former case, but can be two or more in the latter case.

For example, as two or more types of color developing portions capable of developing colors different from each other, a yellow coloring portion capable of developing yellow, a magenta coloring portion capable of developing magenta, and a cyan coloring portion capable of developing cyan Combinations including these are mentioned.
In this case, for example, when only one type of coloring portion is colored by the application of an external stimulus, the toner can be colored in one of yellow, magenta, or cyan, and any two When various types of coloring portions develop color, the colors developed by these two types of coloring portions can be combined, and various colors can be expressed with a single toner particle.

The control of the color to be developed when the toner includes two or more types of coloring portions that can develop colors different from each other depends on the types and combinations of the first component and the second component contained in each type of coloring portion. In addition to making the wavelength different, it can be realized by making the wavelength of light used for curing the photocurable composition contained in each type of color developing portion different.
That is, in this case, since the wavelength of light necessary for curing the photocurable composition contained in the color developing portion differs for each type of color developing portion, a plurality of types having different wavelengths according to the type of color developing portion are used as control stimuli. Coloring information imparting light may be used. In order to make the wavelength of light necessary for curing the photocurable composition contained in the color developing part different, a photopolymerization initiator sensitive to light of a different wavelength is used for each type of color developing part. It is suitable for inclusion in the product.

For example, when the toner includes three types of color-developing parts capable of coloring yellow, magenta, and cyan, the photocurable composition contained in each type of color-forming part has a light wavelength of 405 nm, 532 nm, and If a material that cures in response to any of 657 nm is used, the toner can be colored to a desired color by properly using these three color-developing information-giving lights (lights having specific wavelengths).
The wavelength of the coloring information imparting light can be selected from the visible wavelength, but may be selected from the ultraviolet wavelength.

  The toner used in the present invention may include a base material mainly composed of a binder resin similar to that used in a toner using a colorant such as a conventional pigment. In this case, it is preferable that each of the two or more coloring portions is dispersed as a particulate capsule in the base material (hereinafter, one capsule-like coloring portion may be referred to as a “photosensitive / thermosensitive capsule”). is there). Further, in the base material, a release agent and various additives may be contained in the same manner as a toner using a colorant such as a conventional pigment.

The photosensitive / thermosensitive capsule has a core portion containing a microcapsule or a photocurable composition, and an outer shell covering the core portion, and this outer shell is used in the toner production process and toner storage described later. In the above, there is no particular limitation as long as the microcapsules and the photocurable composition in the photosensitive / thermosensitive capsule can be stably held so as not to leak out of the photosensitive / thermal capsule.
However, in the present invention, in the toner production process described later, the second component passes through the outer shell and flows out to the matrix outside the photosensitive / thermosensitive capsule, or in the photosensitive / thermosensitive capsule capable of developing other colors. In order to prevent the second component from flowing through the outer shell, it is preferable that the second component contains a water-insoluble material such as a binder resin made of a water-insoluble resin or a release material as a main component.

Next, the toner constituent materials used for the F toner and the materials and methods used for adjusting the toner constituent materials will be described in more detail below.
In this case, at least a first component, a second component, a microcapsule containing the first component, and a photocurable composition containing the second component are used for the toner, and a photopolymerization initiator is contained in the photocurable composition. Is particularly preferable, and various auxiliary agents and the like may be included. Further, the first component may be present in a solid state in the microcapsule (core portion), but may be present together with a solvent.

In the light non-color-forming toner, an electron-donating colorless dye or a diazonium salt compound is used as the first component, and an electron-accepting compound having a photopolymerizable group or a photopolymerizable group is used as the second component. A coupler compound or the like is used. In the photochromic toner, an electron-donating colorless dye is used as the first component, and an electron-accepting compound (“electron-accepting developer” or “developer”) is used as the second component. And a polymerizable compound having an ethylenically unsaturated bond is used as the photopolymerizable compound.
In addition to the above-listed materials, various materials similar to those constituting conventional toners using colorants; binder resins, mold release agents, internal additives, external additives, etc., as necessary It can be used as appropriate. Hereinafter, each material etc. are demonstrated in detail.

-1st component and 2nd component-
As the combination of the first component and the second component, the following combinations (a) to (tu) can be preferably mentioned (in the following examples, the former represents the first component and the latter represents the second component, respectively). .

(A) A combination of an electron-donating colorless dye and an electron-accepting compound.
(A) A combination of a diazonium salt compound and a coupling component (hereinafter appropriately referred to as “coupler compound”).
(C) A combination of an organic acid metal salt such as silver behenate or silver stearate and a reducing agent such as protocatechinic acid, spiroindane or hydroquinone.
(D) A combination of a long-chain fatty acid iron salt such as ferric stearate or ferric myristate and a phenol such as tannic acid, gallic acid or ammonium salicylate.
(E) Organic acid heavy metal salts such as nickel, cobalt, lead, copper, iron, mercury and silver salts such as acetic acid, stearic acid and palmitic acid, and alkali metals or alkaline earth such as calcium sulfide, strontium sulfide and potassium sulfide A combination of a metal sulfide or a combination of the organic acid heavy metal salt and an organic chelating agent such as s-diphenylcarbazide or diphenylcarbazone.

(F) A combination of a heavy metal sulfate such as a sulfate such as silver, lead, mercury or sodium and a sulfur compound such as sodium tetrathionate, sodium thiosulfate or thiourea.
(G) A combination of an aliphatic ferric salt such as ferric stearate and an aromatic polyhydroxy compound such as 3,4-hydroxytetraphenylmethane.
(H) A combination of an organic acid metal salt such as silver oxalate or mercury oxalate and an organic polyhydroxy compound such as polyhydroxy alcohol, glycerin or glycol.
(G) A combination of a ferric salt of a fatty acid such as ferric pelargonate or ferric laurate and a thiocesylcarbamide or isothiocecilcarbamide derivative.
(Co) A combination of a lead salt of an organic acid such as lead caproate, lead pelargonate or lead behenate and a thiourea derivative such as ethylenethiourea or N-dodecylthiourea.

(Sa) A combination of a higher aliphatic heavy metal salt such as ferric stearate or copper stearate and zinc dialkyldithiocarbamate.
(B) Those that form an oxazine dye such as a combination of resorcin and a nitroso compound.
(Su) A combination of a formazan compound and a reducing agent and / or a metal salt.
(C) A combination of a protected dye (or leuco dye) precursor and a deprotecting agent.
(So) A combination of an oxidizing color former and an oxidizing agent.
(Ta) A combination of phthalonitriles and diiminoisoindolines. (A combination that produces phthalocyanine.)
(H) A combination of isocyanates and diiminoisoindolines (a combination that produces a colored pigment).
(Iv) A combination of a pigment precursor and an acid or a base (a combination formed by a pigment).

The first component listed above is preferably a substantially colorless electron-donating colorless dye or a diazonium salt compound.
As the electron-donating colorless dye, conventionally known dyes can be used, and any dye that reacts with the second component and develops color can be used. Specifically, phthalide compounds, fluoran compounds, phenothiazine compounds, indolylphthalide compounds, leucooramine compounds, rhodamine lactam compounds, triphenylmethane compounds, triazene compounds, spiropyran compounds, pyridine Examples thereof include various compounds such as phosphines, pyrazine compounds, and fluorene compounds.

  In the case of the non-photochromic toner, the second component is a substantially colorless compound having a photopolymerizable group and a site that develops color by reacting with the first component in the same molecule. Any compound that has both functions of reacting with the first component such as an electron-accepting compound having a photopolymer or a coupler compound having a photopolymerizable group to develop a color and reacting with light to be cured and cured. be able to.

  The electron-accepting compound having a photopolymerizable group, that is, a compound having an electron-accepting group and a photopolymerizable group in the same molecule has a photopolymerizable group and is one of the first components. Any colorant can be used as long as it reacts with an electron-donating colorless dye and develops color and can be cured by photopolymerization.

  The electron-accepting developer as the second component in the case of the photochromic toner includes phenol derivatives, sulfur-containing phenol derivatives, organic carboxylic acid derivatives (for example, salicylic acid, stearic acid, resorcinic acid, etc.), and Examples thereof include metal salts thereof, sulfonic acid derivatives, urea or thiourea derivatives, acidic clay, bentonite, novolac resins, metal-treated novolac resins, metal complexes, and the like.

  Further, in the photochromic toner, a polymerizable compound having an ethylenically unsaturated bond is used as a photopolymerizable compound, and this is at least in a molecule such as acrylic acid and a salt thereof, an acrylic ester, and an acrylamide. It is a polymerizable compound having one ethylenically unsaturated double bond.

  Next, the photopolymerization initiator will be described. The photopolymerization initiator can generate radicals by irradiating with color forming information imparting light to cause a polymerization reaction in the photocurable composition, and can accelerate the reaction. The photocurable composition is cured by this polymerization reaction.

The photopolymerization initiator can be appropriately selected from known ones, and includes, among others, a spectral sensitizing compound having a maximum absorption wavelength at 300 to 1000 nm and a compound that interacts with the spectral sensitizing compound. It is preferable that
However, if the compound that interacts with the spectral sensitizing compound is a compound having both a dye part and a borate part having a maximum absorption wavelength at 300 to 1000 nm in the structure, the spectral sensitizing dye is used. It does not have to be.

As the compound that interacts with the spectral sensitizing compound, one or more compounds are appropriately selected from known compounds capable of initiating a photopolymerization reaction with the photopolymerizable group in the second component. Can be used.
By making this compound coexist with the above-mentioned spectral sensitizing compound, it is sensitive to the irradiation light in the spectral absorption wavelength region and can generate radicals with high efficiency. Generation of radicals can be controlled using an arbitrary light source in the outer region.

  The “compound interacting with the spectral sensitizing compound” is preferably an organic borate salt compound, a benzoin ether, an S-triazine derivative having a trihalogen-substituted methyl group, an organic peroxide or an azinium salt compound. Borate salt compounds are more preferred. By using this “compound that interacts with the spectral sensitizing compound” in combination with the spectral sensitizing compound, radicals can be generated locally and effectively in the exposed exposed portion, thereby increasing the sensitivity. Can be achieved.

In addition, the photo-curable composition further promotes the polymerization by a transfer agent such as an oxygen scavenger or a chain transfer agent of an active hydrogen donor as an auxiliary agent for the purpose of promoting the polymerization reaction. Other compounds can also be added.
Examples of the oxygen scavenger include phosphine, phosphonate, phosphite, first silver salt, and other compounds that are easily oxidized by oxygen. Specific examples include N-phenylglycine, trimethyl parbituric acid, N, N-dimethyl-2,6-diisopropylaniline, and N, N, N-2,4,6-pentamethylanilic acid. Furthermore, thiols, thioketones, trihalomethyl compounds, lophine dimer compounds, iodonium salts, sulfonium salts, azinium salts, organic peroxides, azides and the like are also useful as polymerization accelerators.

In the F toner, a first component such as an electron-donating colorless dye or a diazonium salt compound is encapsulated in a microcapsule.
A conventionally known method can be used as a microencapsulation method. For example, a method using coacervation of hydrophilic wall forming materials described in U.S. Pat. Nos. 2,800,547 and 2,800,458, U.S. Pat. No. 3,287,154, British Patent No. 990443, Japanese Patent Publication No. 38-19574, No. 42 No. -446, No. 42-771, etc., an interfacial polymerization method described in US Pat. Nos. 3,418,250 and 3,660,304, and an isocyanate polyol wall material described in US Pat. No. 3,796,669 are used. A method using an isocyanate wall material described in US Pat. No. 3,914,511, a method using a urea-formaldehyde system, a urea formaldehyde-resorcinol-based wall forming material described in US Pat. Nos. 4001140, 4087376, and 4089802, US 402 A method using a wall forming material such as melamine-formaldehyde resin and hydroxybrovir cellulose described in No. 455, an in situ method by polymerization of monomers described in JP-B No. 36-9168 and JP-A No. 51-9079, Electrolytic dispersion cooling method described in British Patent Nos. 952807 and 965074, US Pat. No. 3,111,407, Spray drying method described in British Patent No. 930422, Japanese Patent Publication No. 7-73069, Japanese Patent Laid-Open No. 4-101858 And the method described in JP-A-9-263057.

  The microcapsule wall material that can be used is added inside and / or outside the oil droplets. Examples of the material of the microcapsule wall include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer, styrene-acrylate copolymer, and the like. Among these, polyurethane, polyurea, polyamide, polyester, and polycarbonate are preferable, and polyurethane and polyurea are more preferable. Two or more kinds of the polymer substances can be used in combination.

  The volume average particle size of the microcapsules is preferably adjusted to be in the range of 0.1 to 3.0 μm, and more preferably adjusted to be in the range of 0.3 to 1.0 μm.

The photosensitive / thermosensitive capsule may contain a binder, and this is the same for a toner having one color developing portion.
Examples of the binder include those similar to the binder used for emulsifying and dispersing the photocurable composition, a water-soluble polymer used for encapsulating the first reactive substance, polystyrene, polyvinyl formal, polyvinyl butyral, poly Acrylic resins such as methyl acrylate, polybutyl acrylate, polymethyl methacrylate, polybutyl methacrylate and copolymers thereof, solvent-soluble polymers such as phenol resin, styrene-butadiene resin, ethyl cellulose, epoxy resin, urethane resin, or these It is also possible to use a polymer latex. Of these, gelatin and polyvinyl alcohol are preferred. Moreover, you may use the binder resin mentioned later as a binder.

  For the F toner, a binder resin used in conventional toners can be used. For example, in a toner having a structure in which photosensitive / thermal capsules are dispersed in a base material, the binder resin can be used as a main component constituting the base material and a material constituting the outer shell of the photosensitive / thermal capsule. It is not limited to this.

  The binder resin is not particularly limited, and a known crystalline or amorphous resin material can be used. In particular, a crystalline polyester resin having sharp melt properties is useful for imparting low-temperature fixability. In addition, as the amorphous polymer (amorphous resin), a known resin material such as a styrene acrylic resin or a polyester resin can be used, but an amorphous polyester resin is particularly preferable.

  In addition, the F toner may contain other components other than those listed above. Other components are not particularly limited and may be appropriately selected depending on the purpose. For example, various known additives used in conventional toners such as release agents, inorganic fine particles, organic fine particles, and charge control agents. Can be mentioned

Next, a method for manufacturing F toner will be briefly described.
The F toner is preferably prepared using a known wet manufacturing method such as an aggregation coalescence method. In particular, a first component and a second component that develop color when they react with each other, a photocurable composition, and a microcapsule dispersed in the photocurable composition, wherein the first component is contained in the microcapsule. The wet manufacturing method is suitable for producing a toner having a structure in which the second component is contained in the photocurable composition.
The microcapsule used for the toner having the above structure is particularly preferably a thermoresponsive microcapsule, but may be a microcapsule that responds to other stimuli such as light.

For the production of toner, a known wet manufacturing method can be used. Among the wet manufacturing methods, the maximum process temperature can be kept low, and the toner having various structures can be easily produced. It is particularly preferable to do this.
Compared to conventional toners mainly composed of pigments and binder resins, toners having the above structure contain more photocurable compositions containing low-molecular components as the main component. Although the strength of the particles obtained by the above method tends to be insufficient, the aggregation and coalescence method does not require a high shearing force, and it is preferable to use the aggregation and coalescence method in this respect as well.

In general, the aggregation and coalescence method includes an aggregation step in which a dispersion of various materials constituting a toner is prepared, and then aggregated particles are formed in a raw material dispersion obtained by mixing two or more types of dispersions. And a coalescing step for fusing the agglomerated particles formed on the surface of the agglomerated particles to form a coating layer between the agglomeration step and the fusing step. The adhesion process (coating layer formation process) to form is implemented.
Also in the production of the F toner, although the types and combinations of the various dispersions used as raw materials are different, the toner can be prepared by appropriately combining the adhering step in addition to the aggregation step and the fusion step.

  For example, in the case of a toner having a photosensitive / thermosensitive capsule dispersion structure in a resin, first, (a1) a microcapsule dispersion in which microcapsules containing a first component are dispersed and a photocurable composition containing a second component A first aggregating step for forming first agglomerated particles in a raw material dispersion containing a photocurable composition dispersion in which a product is dispersed; and (b1) a raw material on which the first agglomerated particles are formed. An adhesion step of adding a first resin particle dispersion in which resin particles are dispersed to the dispersion and attaching the resin particles to the surface of the aggregated particles; and (c1) attaching the resin particles to the surface. One or more types of photosensitive materials that can develop colors different from each other through a first fusion step in which a raw material dispersion containing aggregated particles is heated and fused to obtain first fused particles (photosensitive / heat-sensitive capsules).・ Prepare heat-sensitive capsule dispersion .

Subsequently, (d1) second aggregated particles are formed in a mixed solution obtained by mixing the one or more types of photosensitive / thermosensitive capsule dispersion and the second resin particle dispersion in which the resin particles are dispersed. By passing through a second aggregating step and (e1) a second fusing step of heating the mixed solution containing the second agglomerated particles to obtain second fused particles, a photosensitive / thermosensitive capsule dispersion structure is obtained. A toner having the same can be obtained.
In addition, the kind of photosensitive / heat-sensitive capsule dispersion used in the second aggregation step is preferably two or more. Alternatively, the photosensitive / heat-sensitive capsules obtained through the steps (a1) to (c1) may be used as they are as toner (that is, toner including only one color developing portion).

  In the case of producing a toner including only one color developing portion, a release agent dispersion liquid in which a release agent is dispersed in the raw material dispersion liquid in which the first aggregated particles are formed instead of the above-described adhesion step. And adding a first resin particle dispersion liquid in which resin particles are dispersed in a raw material dispersion liquid after passing through the first adhesion process. A second adhesion step of adding resin particles to the surface of the aggregated particles to which the release agent has been added may be carried out.

The volume average particle size of the F toner that can be used in the present invention is not particularly limited, and can be appropriately adjusted according to the structure of the toner and the type and number of color developing portions contained in the toner.
However, there are about 2 to 4 types of coloring portions that can be developed in different colors contained in the toner (for example, when the toner includes three types of coloring portions that can develop colors of yellow, cyan, and magenta) ), The volume average particle diameter corresponding to each toner structure is preferably within the following range.

  That is, for example, when the toner structure is a photosensitive / thermosensitive capsule (color developing part) dispersion structure in the resin, the volume average particle diameter of the toner is preferably in the range of 5 to 40 μm, more preferably in the range of 10 to 20 μm. . The volume average particle size of the photosensitive / thermosensitive capsule contained in the photosensitive / thermosensitive capsule dispersed structure toner having such a particle size is preferably in the range of 1 to 5 μm, preferably in the range of 1 to 3 μm. It is preferable that

  When the volume average particle diameter of the toner is less than 5 μm, the amount of color developing components contained in the toner decreases, so that color reproducibility may deteriorate and image density may decrease. On the other hand, if the volume average particle size exceeds 40 μm, unevenness on the image surface becomes large, and gloss unevenness on the image surface may occur.

  In addition, the photosensitive / thermosensitive capsule dispersion type toner in which a plurality of photosensitive / thermosensitive capsules are dispersed therein has a particle diameter as compared with a small-diameter toner (volume average particle diameter of about 5 to 10 μm) using a conventional colorant. However, since the resolution of the image is determined not by the particle size of the toner but by the particle size of the photosensitive / heat-sensitive capsule, a higher-definition image can be obtained. In addition, since the powder fluidity is also excellent, sufficient fluidity can be ensured even if the amount of the external additive is small, and the developability and cleaning properties can be improved.

  On the other hand, in the case of a toner having only one color developing portion, it is easier to reduce the diameter as compared with the case described above, and the volume average particle diameter is preferably in the range of 3 to 8 μm, and in the range of 4 to 7 μm. Is preferred. When the volume average particle size is less than 3 μm, the particle size is too small, so that sufficient powder fluidity may not be obtained or sufficient durability may not be obtained. If the volume average particle size exceeds 8 μm, a high-definition image may not be obtained.

  In the present invention, in addition to the F toner described above, any toner can be used as long as it is controlled so as to maintain a colored or non-colored state by light irradiation (or by no light irradiation). It can be used regardless of the structure, coloring mechanism, etc.

The toner that can be used in the present invention has a volume average particle size distribution index GSDv of 1.30 or less and a ratio (GSDv / GSDp) of the volume average particle size distribution index GSDv to the number average particle size distribution index GSDp is 0. .95 or more is preferable.
More preferably, the volume average particle size distribution index GSDv is 1.25 or less, and the ratio (GSDv / GSDp) of the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp is 0.97 or more. Is more preferable.

  When the volume distribution index GSDv exceeds 1.30, the resolution of the image may decrease, and the ratio of the volume average particle size distribution index GSDv to the number average particle size distribution index GSDp (GSDv / GSDp) is If it is less than 0.95, the toner chargeability may be reduced, the toner may be scattered, fogging, etc. may occur, leading to image defects.

In the present invention, the volume average particle diameter of the toner and the values of the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp are measured and calculated as follows.
First, with respect to the divided particle size range (channel) of the toner particle size distribution measured using a measuring device such as Coulter Multisizer II (manufactured by Beckman-Coulter), the smaller diameter side of the volume and number of individual toner particles A cumulative distribution is drawn from the particle size, and the particle size that is 16% cumulative is defined as the volume average particle size D16v and the number average particle size D16p. The particle size that is 50% cumulative is the volume average particle size D50v and the number The average particle size is defined as D50p. Similarly, particle diameters that are 84% cumulative are defined as volume average particle diameter D84v and number average particle diameter D84p. In this case, the volume average particle size distribution index (GSDv) is defined as (D84v / D16v) ^1/2 and the number average particle size index (GSDp) is defined as (D84p / D16p) ^1/2. Can be used to calculate the volume average particle size distribution index (GSDv) and the number average particle size index (GSDp).

  The volume average particle size of the microcapsules or the photosensitive / thermosensitive capsules can be measured using, for example, a laser diffraction particle size distribution measuring device (LA-700, manufactured by Horiba, Ltd.).

In the toner of the present invention, the shape factor SF1 represented by the following formula (1) is preferably in the range of 110 to 130.
SF1 = (ML ² / A) × (π / 4) × 100 (1)
[In the above formula (1), ML represents the maximum length (μm) of toner, and A represents the projected area (μm ² ) of toner. ]

When the shape factor SF1 is less than 110, the toner tends to remain on the surface of the image carrier in the transfer process during image formation. Therefore, it is necessary to remove the residual toner. The cleaning property at the time of cleaning tends to be impaired, and as a result, an image defect may occur.
On the other hand, when the shape factor SF1 exceeds 130, when the toner is used as a developer, the toner may be destroyed due to collision with a carrier in the developing device. At this time, as a result, the fine powder increases or the release agent component exposed on the toner surface may contaminate the surface of the image bearing member and the like to impair the charging characteristics, and the occurrence of fog caused by the fine powder. May cause problems.

  The shape factor SF1 was measured as follows using a Luzex image analyzer (manufactured by Nireco Corporation, FT). First, an optical microscope image of the toner dispersed on the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length (ML) and projected area (A) of 50 or more toners are measured. The square of the maximum length and the projected area were calculated, and the shape factor SF1 was obtained from the above equation (1).

<Developer>
The toner used in the present invention may be used as it is as a one-component developer, but in the present invention, it is preferably used as a toner in a two-component developer comprising a carrier and a toner.
Here, from the viewpoint that a color image can be formed with one type of developer, the developer is (1) a color development including the photocurable composition and microcapsules dispersed in the photocurable composition. One type of toner having two or more types of parts, and two or more types of coloring parts contained in the toner can develop colors different from each other, or (2) the photo-curing property Two or more kinds of toners having one coloring part including a composition and microcapsules dispersed in the photocurable composition, and the coloring parts of the two or more kinds of toners are mixed with each other. It is preferable that the developer be of a type that can develop different colors.

  For example, in the former type of developer, the toner includes three types of color developing portions, and the three types of color developing portions include a yellow color developing portion capable of developing a yellow color and a magenta color forming portion capable of developing a magenta color. In the latter type of developer, a yellow color developing toner that can develop a yellow color and a magenta color that can develop a magenta color. The toner is preferably contained in the developer in a state where the color developing portion and the cyan color developing toner capable of developing a cyan color are mixed.

The carrier that can be used for the two-component developer is preferably formed by coating the surface of the core material with a resin. The core material of the carrier is not particularly defined as long as the above conditions are satisfied, for example, magnetic metals such as iron, steel, nickel, cobalt, alloys of these with manganese, chromium, rare earth, ferrite, magnetite, etc. From the viewpoint of the surface property of the core material and the resistance of the core material, ferrite, particularly an alloy with manganese, lithium, strontium, magnesium or the like is preferable.
Further, the resin for covering the surface of the core material is not particularly limited as long as it can be used as a matrix resin, and can be appropriately selected according to the purpose.

  The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably in the range of toner: carrier = 1: 100 to 30: 100, and in the range of 3: 100 to 20: 100. Is more preferable.

<Test example>
In order to confirm the operation of the above embodiment, the following test was performed.
(toner)
In the following manner, the light non-color-forming F toner in which the light emitting portion (photosensitive / heat-sensitive capsule) was dispersed in the binder resin was obtained.

-Preparation of microcapsule dispersion (1)-
In 16.9 parts by mass of ethyl acetate, 8.9 parts of an electron-donating colorless dye (1) capable of developing a yellow color is dissolved, and capsule wall material (trade name: Takenate D-110N, Takeda Pharmaceutical Co., Ltd.) 20 parts by mass and 2 parts by mass of capsule wall material (trade name: Millionate MR200, manufactured by Nippon Polyurethane Industry Co., Ltd.) were added.
The resulting solution was added to a mixed solution of 42 parts by mass of 8% by mass phthalated gelatin, 14 parts by mass of water, and 1.4 parts by mass of a 10% by mass sodium dodecylbenzene sulfonate solution. Emulsified and dispersed at 0 ° C. to obtain an emulsion. Next, 72 parts by mass of a 2.9% tetraethylenepentamine aqueous solution was added to the obtained emulsion and heated to 60 ° C. with stirring. After 2 hours, the electron-donating colorless dye (1) was added to the core. To obtain a microcapsule dispersion (1) having an average particle size of 0.5 μm.
The glass transition temperature of the material constituting the outer shell of the microcapsule contained in this microcapsule dispersion (1) (the material obtained by reacting Takenate D-110N and Millionate MR200 under the same conditions as above). Was 100 ° C.

-Preparation of microcapsule dispersion (2)-
A microcapsule dispersion (2) was obtained in the same manner as in the preparation of the microcapsule dispersion (1) except that the electron-donating colorless dye (1) was changed to the electron-donating colorless dye (2). The average particle size of the microcapsules in this dispersion was 0.5 μm.

-Preparation of microcapsule dispersion (3)-
A microcapsule dispersion (3) was obtained in the same manner as in the preparation of the microcapsule dispersion (1) except that the electron-donating colorless dye (1) was changed to the electron-donating colorless dye (3). The average particle size of the microcapsules in this dispersion was 0.5 μm.
The chemical structural formulas of the electron donating colorless dyes (1) to (3) used for the preparation of the microcapsule dispersion are shown below.

—Preparation of Photocurable Composition Dispersion (1) —
100.0 parts by mass (mixing ratio 50:50) of a mixture of electron-accepting compounds (1) and (2) having a polymerizable group and 0.1 part by mass of a thermal polymerization inhibitor (ALI) were added to isopropyl acetate (to water). Was dissolved at 42 ° C. in 125.0 parts by mass to obtain a mixed solution I.
In this mixed solution I, hexaarylbiimidazole (1) [2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′tetraphenyl-1,2′-biimidazole] 18.0 Part by mass, 0.5 part by mass of a nonionic organic dye, and 6.0 parts by mass of an organic boron compound were added and dissolved at 42 ° C. to obtain a mixed solution II.
The above mixed solution II was added to a mixed solution of 300.1 parts by mass of an 8% by mass gelatin aqueous solution and 17.4 parts by mass of a 10% by mass surfactant (1) aqueous solution, and a homogenizer (manufactured by Nippon Seiki Co., Ltd.). ) For 5 minutes at a rotational speed of 10,000, followed by desolvation treatment at 40 ° C. for 3 hours to obtain a photocurable composition dispersion (1) having a solid content of 30% by mass.
In addition, the electron-accepting compound (1) which has a polymeric group used for preparation of a photocurable composition dispersion liquid (1), the electron-accepting compound (2) which has a polymeric group, and thermal polymerization inhibitor (ALI) Structural formulas of hexaarylbiimidazole (1), surfactant (1), nonionic organic dye, and organoboron compound are shown below.

-Preparation of photocurable composition dispersion (2)-
0.6 parts by mass of the following organic borate compound (I), 0.1 part by mass of the spectral sensitizing dye-based borate compound (I) shown below, and the following auxiliary agent (1) for the purpose of increasing sensitivity: 5 parts by mass of the following electron-accepting compound (3) having a polymerizable group was added to a mixed solution of 1 part by mass and 3 parts by mass of isopropyl acetate (solubility of about 4.3% in water).

The obtained solution was mixed with 13 parts by weight of a 13% by weight aqueous gelatin solution, 0.8 part by weight of the following 2% by weight surfactant (2) aqueous solution, and 0.8 part by weight of the following 2% by weight surfactant (3) aqueous solution. And emulsified with a homogenizer (manufactured by Nippon Seiki Co., Ltd.) for 5 minutes at a rotational speed of 10,000 rotations to obtain a photocurable composition dispersion (2).
In addition, the electron-accepting compound (3), auxiliary agent (1), surfactant (2) and surfactant (3) having a polymerizable group used for the preparation of the photocurable composition dispersion (2). The structural formula is shown below.

-Preparation of photocurable composition dispersion (3)-
In place of the spectral sensitizing dye-based borate compound (I), the photocurable composition dispersion liquid (2) was used except that 0.1 part by mass of the spectral sensitizing dye-based borate compound (II) shown above was used. A photocurable composition dispersion (3) was obtained in the same manner as in the preparation.

-Preparation of resin particle dispersion-
Styrene: 460 parts by mass nbutyl acrylate: 140 parts by mass Acrylic acid: 12 parts by mass Dodecanethiol: 9 parts by mass The above components were mixed and dissolved to prepare a solution. Subsequently, an emulsion (monomer) in which 12 parts by weight of an anionic surfactant (manufactured by Rhodia, Dowfax) was dissolved in 250 parts by weight of ion-exchanged water, and the above solution was added and dispersed and emulsified in a flask. Emulsion A) was prepared.
In addition, 1 part of an anionic surfactant (Dowfax, manufactured by Rhodia Co., Ltd.) was dissolved in 555 parts by mass of ion-exchanged water and charged into a polymerization flask. The polymerization flask was sealed, a reflux tube was installed, and the polymerization flask was heated to 75 ° C. with a water bath while being slowly stirred while injecting nitrogen.

Next, a solution obtained by dissolving 9 parts of ammonium persulfate in 43 parts by mass of ion-exchanged water was added dropwise to the polymerization flask through a metering pump over 20 minutes, and then the monomer emulsion A was also added to the metering pump. Over 200 minutes.
Thereafter, the polymerization flask was kept at 75 ° C. for 3 hours while stirring slowly, to complete the polymerization.
As a result, a resin particle dispersion having a median particle diameter of 210 nm, a glass transition point of 51.5 ° C., a weight average molecular weight of 31,000, and a solid content of 42% by mass was obtained.

-Preparation of photosensitive / thermosensitive capsule dispersion (1)-
-Microcapsule dispersion (1): 150 parts by mass-Photocurable composition dispersion (1): 300 parts by mass-Polyaluminum chloride: 0.20 parts by mass-Ion exchange water: 300 parts by mass The above ingredients are mixed. Nitric acid is added to the prepared raw material solution to adjust the pH to 3.5, and after thoroughly mixing and dispersing with a homogenizer (IQA, Ultra Tarrax T50), it is transferred to a flask and stirred with a three-one motor in a heating oil bath. While heating to 40 ° C. and holding at 40 ° C. for 60 minutes, 300 parts by mass of the resin particle dispersion was further added and gently stirred at 60 ° C. for 2 hours. Thus, a photosensitive / thermosensitive capsule dispersion (1) was obtained.
The volume average particle size of the photosensitive / thermosensitive capsules dispersed in this dispersion was 3.53 μm. Further, spontaneous color development of the dispersion was not confirmed during the preparation of this dispersion.

-Preparation of photosensitive / thermosensitive capsule dispersion (2)-
-Microcapsule dispersion (2): 150 parts by mass-Photocurable composition dispersion (2): 300 parts by mass-Polyaluminum chloride: 0.20 parts by mass-Ion exchange water: 300 parts by mass A photosensitive / thermosensitive capsule dispersion (2) was obtained in the same manner as in the preparation of the photosensitive / thermosensitive capsule dispersion (1) except that the components were used.
The volume average particle size of the photosensitive / thermosensitive capsules dispersed in this dispersion was 3.52 μm. Further, spontaneous color development of the dispersion was not confirmed during the preparation of this dispersion.

-Preparation of photosensitive / thermosensitive capsule dispersion (3)-
-Microcapsule dispersion (3): 150 parts by mass-Photocurable composition dispersion (3): 300 parts by mass-Polyaluminum chloride: 0.20 parts by mass-Ion exchange water: 300 parts by mass A photosensitive / thermosensitive capsule dispersion (3) was obtained in the same manner as in the preparation of the photosensitive / thermosensitive capsule dispersion (1) except that the components were used.
The volume average particle size of the photosensitive / thermosensitive capsules dispersed in this dispersion was 3.47 μm. Further, spontaneous color development of the dispersion was not confirmed during the preparation of this dispersion.

Photosensitive / thermosensitive capsule dispersion (1): 750 parts by mass Sensitive / thermosensitive capsule dispersion (2): 750 parts by mass Photosensitive / thermosensitive capsule dispersion (3): 750 parts by mass The flask was transferred to a flask, heated to 42 ° C. while heating in the flask, and maintained at 42 ° C. for 60 minutes, and then 100 parts by mass of the resin particle dispersion was further added and gently stirred.
Thereafter, the pH in the flask was adjusted to 5.0 with a 0.5 mol / liter sodium hydroxide aqueous solution, and then heated to 55 ° C. while stirring was continued. During the temperature rise to 55 ° C, the pH in the flask usually drops to 5.0 or lower, but here, an aqueous sodium hydroxide solution is added dropwise to keep the pH from dropping to 4.5 or lower. did. This state was maintained at 55 ° C. for 3 hours.

After completion of the reaction, the mixture was cooled, filtered, thoroughly washed with ion exchange water, and then solid-liquid separated by Nutsche suction filtration. Then, it was redispersed in 3 liters of ion exchange water at 40 ° C. in a 5 liter beaker, and stirred and washed at 300 rpm for 15 minutes. This washing operation was repeated 5 times, followed by solid-liquid separation by Nutsche suction filtration, followed by freeze-drying for 12 hours to obtain toner particles in which photosensitive / thermosensitive capsules were dispersed in a styrene resin. When the particle diameter of the toner particles was measured with a Coulter counter, the volume average particle diameter D50v was 15.2 μm.
Subsequently, 1.0 part by mass of hydrophobic silica (manufactured by Cabot, TS720) was added to 50 parts by mass of the toner particles, and mixed with a sample mill to obtain an externally added toner.

(Developer)
As a carrier, 30% by mass of styrene / acrylic copolymer (number average molecular weight: 23000, weight average molecular weight: 98000, Tg: 78 ° C.) and granular magnetite (maximum magnetization: 80 emu / g, average particle size: 0.5 μm) 70% by mass kneaded, pulverized and classified to a volume average particle size of 100 μm, weighed the toner and the toner concentration to 5% by mass, mixed with a ball mill for 5 minutes, and developed. 1 was obtained.

(Image formation)
An image forming apparatus as shown in FIG. 1 was prepared, and the developing agent 16 was loaded with the developer.
As the photoreceptor 10, a conductive layer is formed by sputtering ITO to a thickness of 3 μm on the surface of a transparent substrate made of cylindrical glass (thickness 3 mm), and a charge generation layer is gallium chloride phthalocyanine on the conductive layer. A multilayer organic photosensitive layer having a film thickness of 25 μm, wherein the charge transport layer contains N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine. What was formed by coating was used.

  As the exposure device 14, an LED image bar having a wavelength of 780 nm capable of forming a latent image with a resolution of 600 dpi was used. The developing device 16 includes a metal sleeve for developing a two-component magnetic brush and can perform reversal development. The toner charge amount when the developer 1 was loaded in the developing unit was about −5 to −30 μC / g.

  As the charge removing device 17 on the surface of the photoconductor, an LED having a peak wavelength of 780 nm is used, and the position of the point where the amount of light irradiated on the surface of the photoconductor 10 is maximum is 10 mm downstream from the development point on the photoconductor 10. And 10 mm upstream from the coloring information application point.

The color-information providing device 28, the peak wavelength of 405 nm (exposure ^{amount: 0.2mJ / cm 2), 532nm} ( exposure ^{amount: 0.2mJ / cm 2), 657nm} ( exposure amount: 0.4mJ / cm ²⁾ light An LED image bar with a resolution of 600 dpi capable of irradiating the image was placed inside the photoconductor 10, and the point of coloring information was placed 20 mm away from the development point on the photoconductor surface. The transfer device 18 includes a semiconductive roll formed by coating a conductive elastic body on the outer periphery of a conductive core material as a transfer roll. The conductive elastic body is made by dispersing two types of carbon black consisting of ketjen black and thermal black in an incompatible blend formed by mixing NBR and EPDM, and has a roll resistance of 10 ^8.5 Ωcm, The Asker C hardness is 35 degrees.

  The fixing device 22 used was a fixing device used in DPC1616 manufactured by Fuji Xerox Co., Ltd., and was arranged at a position 30 cm from the point of coloring information application. Moreover, as the light irradiation means 24, the high-intensity shakasten containing the three wavelengths of the said coloring information provision apparatus was used, and the irradiation width was 5 mm.

The printing conditions were set as follows by the image forming apparatus having the above configuration.
Photoconductor linear velocity: 100 mm / sec.
-Charging conditions: -400V applied to scorotron screen and -6kV DC applied to wire. At this time, the surface potential of the photosensitive member was −400V.
-Exposure: The exposure was performed with a logical sum of image information for four colors of Y, M, C, and black, and the potential after the exposure was about -50V.
Development bias: A rectangular wave of alternating current Vpp 1.2 kV (3 kHz) is superimposed on direct current −330V.
Developer contact conditions: peripheral speed ratio (development roll / photoreceptor) 2.0, development gap 0.5 mm, developer weight on the development roll 400 g / m ² , toner development amount on the photoreceptor was solid The image was 5 g / m ² .
-The illuminance of the LED, which is a photostatic device, was adjusted to 1000 lux, and the photoreceptor surface potential after charge removal was adjusted to -150V.
Transfer bias: DC + 800V applied.
Fixing temperature: The fixing roll surface temperature is set to 180 ° C.
-Light irradiation device illuminance: 130000 lux.

  Under the above conditions, a chart having a gradation image portion was printed for each color of Y, M, C, R, G, B, and K. The coloring information was imparted to the toner in the combinations shown in Table 1 below (indicating that the toner is colored in a desired color when the LED marked with a circle emits light). In addition, in order to control the color density by the light emission intensity or the light emission time, time width modulation in which the time of one dot is divided into eight is adopted.

(Image evaluation)
The following evaluation was performed about the print sample obtained on the said conditions. In addition, as a print sample at the time of evaluation, as an image pattern, the first sheet was composed of a solid color of yellow, magenta, and cyan, a secondary color, a secondary color, a 2 cm square large, and a line image.

The following evaluation was performed about the print sample obtained on the said conditions.
-Color density-
When the image density of the solid image part for each of the colors Y, M, and C was examined with a density measuring device X-Rite 938 (manufactured by X-Rite), the image density was 1.5 or more and sufficient color development was obtained for any color. confirmed.

-Image quality-
When the image was visually checked for the presence or absence of toner scattering, a good print with no blur on the edge of the solid portion or the line image was obtained for any color image.

  Next, when the image serving as the light static eliminating device was turned off and the image was output in the same manner, a similar color development was obtained, but a noticeable blur was observed on the edge and line image of the solid portion.

  As described above, in the image forming apparatus (image forming method) that exposes the toner image on the surface of the photoconductor with the color forming information-imparting light, the toner is provided by providing the charge removing unit that reduces the surface potential of the photoconductor before the exposure. A high-quality image with excellent color development and no blurring could be obtained.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention. It is typical sectional drawing which shows an example of the state which is performing charge removal. It is typical sectional drawing which shows another example of the state which is performing charge removal. It is a circuit block diagram of a printing control unit. It is a figure which shows the state which is providing color development information after reversal development like an electric potential model. 2A and 2B are schematic diagrams for explaining a toner color development mechanism, in which FIG. 1A shows a color development portion and FIG. 2B shows an enlarged state thereof.

Explanation of symbols

4 Reflecting means 10, 52 Photoconductor 12 Charging device 14 Exposure device 16 Development device 17 Charge removal device 18 Transfer device 20 Cleaner 22 Fixing device 24 Light irradiation device 26 Recording medium 28 Color development information provision device 34 Color development information provision exposure head 36 Printer controller 38 Exposure unit 40 OR circuit 42 Oscillation circuit 44 Color control circuit 50, 58 Corotron (charge removing means)
54 Toner images 56, 60, 64 Color development information imparting exposure 62 Toner layer 70 Microcapsule 72 Color developer 74 Developer monomer 76 Photopolymerization initiator 80 Color development part

Claims (10)

An image forming apparatus using toner that is controlled to maintain a colored state or a non-colored state by providing coloring information by light,
An image bearing member; a charging unit that charges the surface of the image bearing member; an electrostatic latent image forming unit that forms an electrostatic latent image on the charged image bearing member surface; A developing means for forming a toner image with a developer containing the color; a coloring information giving means for giving color development information by light to the toner image formed on the surface of the image carrier; and a toner image to which the color development information is given Transfer means for transferring to the recording medium, fixing means for fixing the toner image transferred to the surface of the recording medium by heat and / or pressure, and coloring means for coloring the toner image to which the coloring information is given by heating. ,
And a charge removing unit that is disposed downstream of the developing unit in the moving direction of the image carrier and lowers the potential of at least the vicinity of the toner image on the surface of the image carrier before exposure by the color information providing unit. An image forming apparatus.   The image according to claim 1, wherein the charge removing unit is a light discharging unit, and the irradiation light in the light discharging unit has a wavelength range in which the toner image is not absorbed but only the image carrier is absorbed. Forming equipment.   The image forming apparatus according to claim 1, wherein the charge removing unit is a non-contact charging unit.   The image forming apparatus according to claim 1, wherein the charge removing unit is a contact charging unit.   The color information imparting means exposes the toner image formed on the surface of the image carrier from the back side of the image carrier, and imparts color information to the toner image by light transmitted through the image carrier. The image forming apparatus according to claim 1, wherein the image forming apparatus is a means.   The charge removing means is disposed opposite to the color information providing means via the image carrier, and has a reflection means for reflecting light that gives color information to the toner image transmitted through the image carrier. The image forming apparatus according to claim 5.   The image forming apparatus according to claim 1, wherein the charge removing unit is disposed at the same position as an exposure position by the coloring information providing unit with respect to the image carrier.   The image forming apparatus according to claim 1, further comprising a light irradiation unit configured to irradiate the recording medium surface after fixing with light.   A first component and a second component that are present in a state where the toners are isolated from each other and react with each other; and a photocurable composition containing any one of the first component and the second component. 2. The toner according to claim 1, wherein the photocurable composition maintains a cured or uncured state by the application of color development information by light, and the reaction for color development is controlled. The image forming apparatus described. An image forming method using a toner controlled to maintain a colored state or a non-colored state by providing coloring information by light,
A charging step for charging the surface of the image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the charged surface of the charged image carrier, and a toner containing the electrostatic latent image by a developer containing the toner. A developing step for forming an image, a coloring information providing step for imparting coloring information by light to the toner image formed on the surface of the image carrier, and a transfer step for transferring the toner image to which the coloring information is imparted to the surface of the recording medium And a fixing step of fixing the toner image transferred to the surface of the recording medium by heat and / or pressure, and a coloring step of coloring the toner image provided with the coloring information by heating,
And a charge removing step of lowering the potential of at least the toner image on the surface of the image carrier before exposure for providing the color development information on the downstream side in the moving direction of the image carrier from the developing step. Image forming method.

Images