JP2006267519A - Stereoscopic image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stereoscopic image forming apparatus which provides satisfactory projection and color development on any part with respect to a stereoscopic image including a part where color toner exists and a part where the color toner does not exist. <P>SOLUTION: The stereoscopic image forming apparatus comprises: color toner image forming means 5Y, 5M, 5C, 5K which form color toner images; a foam toner image forming means 5P which forms a foamed toner image; an intermediate transfer body 23 where the color toner image and the foamed toner image are formed on the surface and, thereby, a color foamed toner image is formed; a transfer means 24 which transfers the color foamed toner image to the surface of a medium to be recorded; a fixation means 25 which fixes the color foamed toner image; and a transparent toner image forming means 5T which forms a transparent toner image with a transparent toner before forming the foamed toner image by means of the foamed toner image forming means 5P. The transparent toner image forming means 5T is a means for forming the transparent toner image on the part where the foamed toner image in the color foamed toner image on the surface of the intermediate transfer body 23 is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stereoscopic image forming apparatus that forms a full-color semi-stereoscopic image using an electrophotographic process, an electrostatic process, or the like.

  Semi-stereoscopic images (protruding images) can transmit not only planar visual information, but also information such as shadows due to height differences and tactile sensation of the fingers, so they have a wide variety of uses and are very useful. . As a method for forming this stereoscopic image, the following methods are known.

Patent Document 1 discloses an image capable of forming a multi-color image on a recording medium using a stereoscopic image toner containing at least a binder resin and a foaming agent, and the foaming agent is not substantially exposed on the toner surface. A technique for use in a forming apparatus is disclosed.
In Patent Document 2, a toner image composed of a heat-foamable toner and a color toner image composed of a non-foamable full-color toner are transferred to the surface of a recording medium, and then subjected to a heat-fixing process, whereby a heat-foamable toner is obtained. Has been disclosed in which a three-dimensional image is formed by thermally foaming and a color three-dimensional image is formed by melting and fixing a color toner image made of a non-foamable toner.

  In the formation of these color three-dimensional images, an intermediate transfer member is used and a color toner image and a foamed toner image made of a heat-foamable toner are laminated on the intermediate transfer member. When the transfer is applied to the image forming apparatus, the transfer efficiency is different between the portion where only the heat-foamable toner is present and the portion where the color toner and the heat-foamable toner are overlapped. Therefore, no matter how the transfer conditions such as transfer applied voltage, current, and transfer pressure are controlled, the foamed toner image of only the heat-foamable toner is not sufficiently transferred, and the bulge after fixing is insufficient, The color toner image of the portion where the color toner and the heat-foamable toner overlap with each other is not sufficiently transferred, and the color development is insufficient, or the foamed toner image is not sufficiently transferred and the protrusion is not sufficient. There was a problem.

JP 2000-131875 A JP 2002-244384 A

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is to make any part of a stereoscopic image including a portion where a color toner is present and a portion where a color toner is not present good. An object of the present invention is to provide a three-dimensional image forming apparatus that realizes uplift and color development.

The above object is achieved by the present invention described below. That is, the present invention provides a color toner image forming unit that forms a color toner image by laminating three or more color toners, a foamed toner image forming unit that forms a foamed toner image using a thermally foamable toner, and the color toner. An intermediate transfer member on which a color foamed toner image is formed by laminating an image and the foamed toner image on the surface; transfer means for transferring the color foamed toner image on the surface of the intermediate transfer member onto the surface of a recording medium; A three-dimensional image forming apparatus comprising: a fixing unit that foams and fixes the color foamed toner image transferred to the surface of the recording medium by applying heat at least;
Further, prior to the formation of the foamed toner image by the foamed toner image forming means, the transparent toner image forming means for forming a transparent toner image with the transparent toner, and
The three-dimensional image formation characterized in that the transparent toner image forming means is a means for forming a transparent toner image on a portion of the color foamed toner image of the recording medium on the paper conveying belt to which the foamed toner image is transferred. Device.

The present invention can also be applied to an apparatus that directly forms a toner image on a recording medium carried on a paper conveyance belt without including an intermediate transfer member. That is, the three-dimensional image forming apparatus of the present invention having the above configuration includes a color toner image forming unit that forms a color toner image by laminating three or more color toners, and a foamed toner that forms a foamed toner image using a thermally foamable toner. An image forming means, a transfer means for transferring the color foamed toner image onto the surface of the recording medium on a paper conveying belt by laminating the color toner image and the foamed toner image on the surface; A three-dimensional image forming apparatus comprising: a fixing unit configured to foam and fix at least heat to a color foamed toner image;
Further, prior to the formation of the foamed toner image by the foamed toner image forming means, the transparent toner image forming means for forming a transparent toner image by the transparent toner, and
The transparent toner image forming means is means for forming a transparent toner image on a portion of the color foamed toner image of the recording medium on the paper conveying belt where the foamed toner image is transferred. .

  In the present invention, the transparent toner image forming means is configured to add the transparent toner to at least a three-dimensional image portion made of only the heat-expandable toner that does not overlap with the color toner. As a result, the transfer efficiency of the portion where only the heat-foamable toner without the color toner is present and the portion where the color toner and the heat-foamable toner are overlapped are equal. Accordingly, it is possible to realize a good bulge and color development at any part of a stereoscopic image including a part with and without a color toner.

  As the transparent toner used in the transparent toner image forming unit, the color toner used in the color toner image forming unit, and the particle size, charge distribution, and shape thereof are each (more preferably two or more, more preferably all). It is preferable that they are substantially the same. By aligning the toner superimposed on the foamed toner image with the heat-foamable toner to the same physical properties as possible with the color toner and the transparent toner, the transfer efficiency can be leveled, and good bumps and color can be obtained at any part. Color development can be realized at a high level.

  In the transparent toner image forming means, the total toner amount of the color toner image and the transparent toner image at the portion where the foamed toner image is formed in the color foamed toner image on the surface of the intermediate transfer member is the color toner image formation. It is preferable to form a transparent toner image so that the amount of toner is at least twice the amount of toner when a monochromatic solid image is formed by means.

  In the color toner image, the color toner remains as a single layer depending on the part, or two to three layers are laminated to form a full color image, but the foamed toner image in the color foamed toner image on the surface of the intermediate transfer member is formed. The amount of color toner in the portion of the single-color halftone image in the portion to be printed and the portion of the solid image (particularly, process black obtained by stacking solid images of three colors of toner) by mixing two or three colors The transfer efficiency is very different and the transfer efficiency is naturally different. Therefore, by forming the transparent toner image so that the total toner amount of the color toner image and the transparent toner image is at least twice the amount of toner when the single color solid image is formed by the color toner image forming unit, The difference in transfer efficiency depending on the part can be further leveled.

  Further, in the transparent toner image forming means, the sum of the toner amounts of the color toner image and the transparent toner image at the portion where the foamed toner image is formed in the color foamed toner image on the surface of the intermediate transfer member is made uniform. In addition, if a transparent toner image is formed, the difference in transfer efficiency depending on the part can be further leveled.

  According to the three-dimensional image forming apparatus of the present invention, the foamed toner image formed on the surface of the intermediate transfer member does not have a portion that directly contacts the surface of the intermediate transfer member, and always passes through a color toner image and / or a transparent toner image. The transfer efficiency from the intermediate transfer member to the recording medium is leveled, and a good bulge and color development can be achieved at any part of the stereoscopic image including the part with and without the color toner. Can do.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments.
First, a schematic configuration of a stereoscopic image forming apparatus according to an embodiment which is an exemplary aspect of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram schematically illustrating a schematic configuration of the stereoscopic image forming apparatus of the present embodiment.

  In FIG. 1, a stereoscopic image forming apparatus 10 capable of forming a color image is provided with, for example, an original reading apparatus 3 that reads an image of an original A pressed by a platen cover 2 on the upper part thereof, while Inside, a transparent toner image forming unit (transparent toner image forming means) 5T, a color toner image forming unit (color toner image forming means) 5Y, 5M, 5C, 5K, and a foamed toner image forming unit (foamed toner image forming means) 5P An image forming unit 5 is provided. Below the image forming unit 5, sheet supply trays 7 capable of accommodating a large amount of recording paper are arranged in multiple stages.

  The document reader 3 illuminates a document placed on the platen glass with a light source (not shown), and reflects a reflected light image from the document A via a full-rate mirror, a half-rate mirror, and an imaging lens (not shown). For example, scanning exposure is performed on an image reading element (light receiving element) made of a CCD, for example, and the color material reflected light image of the original A is read at a predetermined dot density (for example, 16 dots / mm) by the image reading element. Yes.

The stereoscopic image forming apparatus 10 is connected to a personal computer 50. For example, the user instructs to set a processing process such as a stereoscopic process from image information read by the document reading apparatus 3, and the result is displayed as a stereoscopic image. By transmitting to the forming apparatus 10, various stereoscopic images can be formed. The personal computer 50 has a software configuration such as application software. The personal computer 50 also includes image editing software relating to a stereoscopic image and software for converting and transferring image data to output data corresponding to a printer.
Further, for example, a liquid crystal touch panel (not shown) is provided as a user interface on the upper portion of the stereoscopic image forming apparatus 10, and a user's operation instruction can be input from the liquid crystal panel.

  The image forming unit 5 according to the present embodiment employs an electrophotographic system, for example, and is a so-called tandem type full-color three-dimensional image forming unit. Specifically, a color image of a transparent toner layer forming unit (transparent toner image forming unit) 5T, four colors (in this embodiment, Y (yellow), M (magenta), C (cyan), K (black)). Layer forming units (color toner image forming means) 5Y, 5M, 5C, 5K and a foamed toner layer forming unit (foamed toner image forming means) 5P are sequentially arranged in the horizontal direction (from right to left in FIG. 1), and above Is provided with an intermediate transfer belt (intermediate transfer member) 23 that is circulated and conveyed in a predetermined direction (in this example, clockwise in the figure) along the arrangement direction of the image forming units 5T to 5P. On the other hand, a transparent toner cartridge 6T, color toner cartridges 6Y to 6K, and a foaming agent toner cartridge 6P corresponding to the image forming units 5T to 5P are disposed above the image forming units 5T to 5P.

  Each of the image forming units 5 includes a photosensitive drum 52 (TP) that forms and carries a toner image of each component. Around the photosensitive drum 52 (TP), the photosensitive drum 52 (TP) A charger 521 (TP) for charging (TP) to TP), an exposure device (not shown) such as a laser scanning device for writing an electrostatic latent image on the surface of the photosensitive drum 52 (TP), and toner for each component are accommodated. The developing device 523 (TP) that visualizes the electrostatic latent image on the surface of the photosensitive drum 52 (TP), and the intermediate transfer of each component toner image on the surface of the photosensitive drum 52 (TP). For example, a primary transfer device 524 (TP) made of a transfer roll and a cleaner 525 (TP) for cleaning residual toner on the surface of the photosensitive drum 52 (TP) are transferred to the surface of the belt (intermediate transfer member) 23. Each of the electrophotographic devices is arranged .

  The intermediate transfer belt 23 is circulated and conveyed by being stretched around a plurality of stretching rolls. The secondary transfer portion downstream of the image forming unit 5P in the circulation and conveyance direction of the intermediate transfer belt 23 has a secondary transfer portion. A transfer device (transfer means) 24 is provided. The secondary transfer device 24 includes a backup roll 241 that stretches the intermediate transfer belt 23 and a secondary transfer roll 242 that is disposed to face the backup roll 241. In FIG. 1, reference numeral 231 denotes a cleaner for cleaning the intermediate transfer belt 23.

The toner image of each component formed on the surface of each photosensitive drum 52 (TP) is transferred to the primary transfer device 524 (on the surface of the intermediate transfer belt 23 in contact with the photosensitive drum 52 (TP). (T to P) are sequentially primary-transferred and stacked in layers at the nip portion formed by the primary transfer roll. The toner image that has been primary-transferred multiple times onto the surface of the intermediate transfer belt 23 is secondarily transferred to the recording medium S by the secondary transfer device 24, and then the secondary-transferred recording medium S is secondary-transferred. It is guided to a fixing device (fixing means) 25 disposed on the downstream side in the transport direction of the recording medium S of the device 24. The fixing device 25 includes, for example, a pressure roll 251 and a heating roll 252 that face each other, and a recording medium S that has been secondarily transferred is formed by the pressure roll 251 and the heating roll 252. A three-dimensional image is formed on the surface of the recording medium S by being introduced into the nip portion and heated and pressurized and fixed at a predetermined temperature (about 140 ° C. to 190 ° C.).
In the present embodiment, the foamed toner layer refers to a toner layer made of a heat-expandable toner that expands and forms a raised image by heat fixing (about 140 ° C. to 190 ° C.).

  The foaming agent used in the heat-foamable toner is not particularly limited, and any foaming agent can be used as long as it expands by heat. It may be solid at room temperature or liquid. The foaming agent is not limited to a material made of a single substance, and may be a material made of a plurality of substances or a functional material such as a microcapsule. Further, the foaming temperature is preferably not more than the heat fixing temperature (generally about 140 ° C. to 190 ° C.).

  The binder resin of the heat-foamable toner is not particularly limited, and a resin generally used as a toner resin can be used. Specifically, a polyester resin, a styrene resin, an acrylic resin, a silicone resin, an epoxy resin, a diene resin, a phenol resin, an ethylene vinyl acetate resin, and the like are preferable, and a polyester resin is more preferable.

As a method for producing the thermally foamable toner in the present embodiment, for example, an oil phase in which at least a binder resin and a foaming agent are dissolved and / or dispersed in a solvent is suspended and dispersed in an aqueous phase, and then the oil phase is used. And a step including a step of removing the solvent from the particle. Moreover, you may produce by the process including the process of carrying out suspension polymerization of the monomer for binder resin which melt | dissolved or disperse | distributed the foaming agent at least in an aqueous phase.
Of course, each of the above toners may be produced by any method such as a kneading and pulverizing method, a polymerization method, and a dissolution suspension method.

  In the three-dimensional image forming apparatus 10 configured as described above, the image forming unit 5 including the transparent toner image forming unit 5T, the color toner image forming units 5Y, 5M, 5C, and 5K, and the foamed toner image forming unit 5P is photosensitive. Each component toner image is formed on the surface of the body drums 52T, 52Y, 52M, 52C, 52K, and 52P, and is formed on the nip portion formed by the primary transfer rolls of the corresponding primary transfer devices 524T, 524Y, 524M, 524C, 524K, and 524P. Then, the toner image is primarily transferred and formed on the surface of the intermediate transfer belt 23. Specifically, first, a transparent toner layer T is formed on the surface of the intermediate transfer belt 23, and after the color toner layers Y, M, C, and K are sequentially transferred onto this layer, these color toner layers are further transferred. The foamed toner layer P is transferred and formed thereon. Then, these toner layers are collectively transferred at a secondary transfer site to the recording medium S supplied from the sheet supply tray 7 at a predetermined timing, and a heating roll 252-a pressure roll of the fixing device 25. The three-dimensional image is fixed on the recording medium S while the recording medium S is passed through the recording medium 251.

  At this time, the foamed toner layer P, the color toner layers K, C, M, and Y and the transparent toner layer T are collectively laminated on the recording medium S from the recording medium S side. (Of course, not all these layers are formed in all parts.) Then, the foamed toner layer P formed in the lowermost layer expands and expands by heat fixing, and a full-color three-dimensional image is formed together with the color toner layers Y, M, C, and K formed on the surface thereof. Here, the transparent toner layer T hardly contributes to the visual effect.

The formation of the transparent toner layer, which is a characteristic structure of the present invention, will be described.
FIG. 2 is a schematic cross-sectional view showing an example of the surface state of the recording medium S when the transparent toner layer is not formed. On the surface of the recording medium S, a foamed toner layer P and a color toner layer F are sequentially laminated. In FIG. 2, the four color toner layers Y, M, C, and K are collectively shown as a color toner layer F without distinction.

  In the present invention, a transparent toner image (on all the portions where only the foamed toner image (foamed toner layer) is formed in the color foamed toner image (toner image formed by the foamed toner layer and the color toner layer) on the surface of the intermediate transfer member. It is characteristic that it is configured to form a transparent toner layer.

  Referring to FIG. 2, first, of the regions (1) to (7), the regions (2), (4), and (6) that are portions where the foamed toner layer P is not formed are the color toner layer F. The formation of the transparent toner layer T is not essential regardless of whether or not the toner is formed. That is, the formation of the transparent toner layer T becomes a problem in the regions (1), (3), (5), and (7) that are portions where the foamed toner layer P is formed. Of these portions, the portion where the foamed toner layer P is exposed on the surface is inferior in transferability when transferring from the intermediate transfer member to the recording medium S as compared with the portion where the color toner F is interposed. For this reason, it is desirable to approximate the transferability in the state where the color toner F is interposed. In the present invention, by forming the transparent toner layer T in such a poorly transferable part, the transfer efficiency by the part is leveled.

  First, it is not essential to form the transparent toner layer T in the region (7) where the color toner layer F is formed on the entire surface. On the contrary, the transparent toner layer T is indispensable for the region (5) where the color toner layer F is not formed on the entire surface and the foamed toner layer P is exposed.

  In addition, in the regions (1) and (3) where the color toner layer F is partially formed on the surface, it is essential to form the transparent toner layer T only in the portion where the foamed toner layer P is exposed. Become. Specifically, the formation of the transparent toner layer T is essential for the small area b in the area (1) and the small areas b and d in the area (3).

  Each portion where the formation of the transparent toner layer T is essential must be already formed at the stage of the state of FIG. 2 where the toner image is transferred onto the surface of the recording medium. At the stage where the color toner layer F (Y, M, C, K) and the foamed toner layer P are laminated on the surface of the transfer belt 23, they are simultaneously formed. More specifically, as described above, the transparent toner layer T is first formed, and after the color toner layers Y, M, C, and K are sequentially transferred, the foamed toner layer P is further formed on these toner layers. Will be formed.

FIG. 3 is a schematic cross-sectional view showing a state where the transparent toner layer T, the color toner layer F, and the foamed toner layer P are transferred and formed on the surface of the intermediate transfer belt 23. The foamed toner layer P is formed on each part where the formation of the transparent toner layer T is essential, that is, the small area b in the area (1), the small areas b and d in the area (3), and the area (5). Prior to this, a transparent toner layer T is formed on the surface of the intermediate transfer belt 23.
Then, the toner image is secondarily transferred to the recording medium S by the secondary transfer device 24 in FIG. 1, and the color toner layer F or the transparent toner layer T is exposed.

  As can be seen from FIG. 3, according to the three-dimensional image forming apparatus of the present invention, there is no portion where the foamed toner layer P is in direct contact with the surface of the intermediate transfer belt 23, and the color toner layer F or the transparent toner layer T is always used. It has become a state. Therefore, there is no variation in transfer efficiency depending on the part, and leveling can be performed, and good bulge and color development can be realized at any part.

  The toner amount of the transparent toner image T to be formed is sufficient as long as the toner image is uniformly formed and the foamed toner layer P is not in direct contact with the surface of the intermediate transfer belt 23. The amount of toner is preferably 50% or more, more preferably 80% or more, and even more preferably 100% or more of the amount of toner when a monochromatic solid image is formed with F. As will be described later, it may be preferable to form the transparent toner layer with a larger amount of toner.

  In the present embodiment, an example in which the transparent toner layer T is formed only in a portion where only the foamed toner layer P is formed is described as an example. However, in the present invention, at least only the foamed toner layer P is formed. The formation of the transparent toner layer T is required at a site, and the formation of the transparent toner layer T is optional for other sites, and is appropriately selected according to the purpose and the like.

FIG. 4 shows only the region (3) in FIG. 3 and enlarges it, and omits the foamed toner layer P (in other words, the intermediate transfer belt 23 just before the foamed toner layer P is formed). It is a schematic cross-sectional view showing a surface state. As described above, in this region, there is no portion where the foamed toner layer P is in direct contact with the surface of the intermediate transfer belt 23, and the color toner layer F (F ₁ and F ₂ ) or the transparent toner layer T is always used. Therefore, the transfer efficiency is leveled at any part. In this example, the color toner layer F ₂ is a tertiary color layer in which the three colors of the color toner layers Y, M, and C are laminated, and the total amount of all the color toners is the same as when a single color solid image is formed. The amount exceeds twice the amount of toner.

However, the color toner layer F ₁ and the color toner layer F ₂ have greatly different color toner amounts as indicated by h _x and _hy in FIG. Of course, it can be said that both transfer efficiencies are close to each other in comparison with a portion where neither the color toner layer nor the transparent toner layer is interposed, but strictly speaking, there is a difference in transfer efficiency. Therefore, it is desirable to form the transparent toner image so that the total toner amount of the color toner image and the transparent toner image is at least twice the amount of toner when the color solid image forming unit forms a single color solid image. .

FIG. 5 shows that the total toner amount of the color toner image and the transparent toner image is twice the amount of toner when the solid color image is formed by the color toner image forming unit with respect to the region (3) in FIG. FIG. 6 is a schematic cross-sectional view showing a state where a transparent toner image is formed. In this example, the transparent toner layer T ′ is formed not only in the small areas b and d where the color toner layer is not formed, but also in the small area a where the thin color toner layer F ₁ is formed. It has a h _Z total is twice the toner amount in the case of forming a single color solid image. Therefore, the total amount of toner in the small areas a, b, and d is unified to h _Z , and even when compared with the toner amount _hy of the small area c in which the color toner layer F ₂ having the tertiary color and the large amount of toner is formed. The difference is slight. Therefore, the total toner amount of the color toner layer F (F ₁ and F ₂ ) and the transparent toner layer T ′ interposed between the surface of the intermediate transfer belt 23 and the foamed toner layer P is leveled, and FIGS. Compared to the example of FIG. 5, the difference in transfer efficiency depending on the part is also leveled.

To further smooth the difference in transfer efficiency by site may be to even out even a slight difference between the toner amount h _y subregions a, b and d of the toner amount h _Z and a small region c. Specifically, the transparent toner is set so that the total toner amount of the color toner image and the transparent toner image is more than twice the amount of toner when a single color solid image is formed by the color toner image forming unit. It is preferable to form an image, and most preferably, the amount of toner is three times or more the amount of toner when a single color solid image is formed by the color toner image forming means.

  In addition, the total toner amount of the color toner image and the transparent toner image at the portion where the foamed toner image is formed in the color foamed toner image on the surface of the intermediate transfer member is uniform instead of the specific toner amount. If a transparent toner image is formed so that the total amount of toner is uniform, the transfer efficiency is further leveled. The toner amount of the transparent toner image is such that the toner amount of the color toner image at the portion where the foamed toner image is formed in the color foamed toner image on the surface of the intermediate transfer member is aligned to the maximum value (that is, all the portions are aligned). The total toner amount of the color toner image and the transparent toner image may be set to the maximum value of the toner amount of the color toner image).

FIG. 6 is a schematic cross-sectional view showing a state in which a transparent toner image is formed so that the total toner amount of the color toner image and the transparent toner image is uniform with respect to the region (3) in FIG. In this example, a transparent toner layer T ″ is formed in the small areas a, b and d, and the total amount of these toners is that of the small area c where the color toner layer F ₂ having a tertiary color and a large amount of toner is formed. has become equal to the toner amount h _y. Accordingly, the toner amount of the color interposed toner layer F (F ₁ and F ₂₎ and the transparent toner layer T "between the surface of the intermediate transfer belt 23 and the expandable toner layer P Is almost uniform, and the transfer efficiency by the part is further leveled.

In order to level the transfer efficiency with high accuracy between the part where the color toner is formed and the part where the transparent toner is formed, the physical properties of the color toner and the transparent toner to be used, for example, the particle size, shape and charge amount are It is desirable to approximate as much as possible, and it is particularly preferable that they are substantially the same.
The toner particle size, shape, and charge amount are substantially the same, which means that the difference can be considered to be substantially the same in view of physical characteristics. The reference of is helpful.

  As for the particle diameter of the toner, the volume average particle diameter of the transparent toner is preferably in the range of 50 to 200%, more preferably in the range of 75 to 150% with respect to the color toner.

The shape of the toner can be considered by the toner shape factor SF-1. Here, the toner shape factor SF-1 is an index representing the degree of toner sphere. The closer the shape factor SF-1 is to 100, the closer it is to a sphere. In the true sphere, the shape factor SF-1 is 100. Become. Specifically, it is represented by the following formula (1).
SF-1 = (π / 4 ) × (ML 2 / A) × 100 ··· (1)
ML: Maximum length of diameter in projected image of toner A: Projected area in projected image of toner As the shape factor SF-1 of the toner, the difference between the transparent toner and the color toner is preferably within 30%. More preferably, it is within%.

As for the charge amount of the toner, the absolute value of the transparent toner value is preferably within ± 50%, more preferably within ± 20% of the absolute value of the color toner.
The charge amount of the toner can be easily measured by a conventionally known method, and further using a commercially available charge amount measuring device (for example, a charge amount measuring device TB300 manufactured by Toshiba Chemical Corporation).

  As the color toner that can be used in the present invention, various color toners produced by any conventionally known method can be used. However, in order to adjust the particle size and shape to align with a transparent toner, a wet manufacturing method (for example, an emulsion polymerization method, an emulsion aggregation method, an interfacial polymerization method) having a shape controllability higher than that of a dry manufacturing method such as a kneading pulverization method. , Suspension polymerization and the like).

  The color toner contains a binder resin and a coloring material as essential components, and, if necessary, a wax and other internal additives are added. In addition, various external additives are generally added to improve graininess and chargeability. Of course, the color toner used in the present invention may be appropriately added. Preferred materials, preferred amounts, and the like for these materials can be appropriately selected based on conventionally known knowledge.

On the other hand, the transparent toner can also be produced by any conventionally known method, but the wet production method is preferable for the same reason as the color toner.
Transparent toner is basically a product obtained by removing color material from color toner, and the binder resin to be used is not particularly limited, and a resin generally used as a resin for toner is used as it is. can do. Specifically, polyester resins, styrene resins, acrylic resins, silicone resins, epoxy resins, diene resins, phenol resins, ethylene vinyl acetate resins, and the like can be listed as binder resins. Among them, polyester resins are selected. It is preferable.
From the viewpoint of approximating the physical characteristics of the color toner and the transparent toner, it is desirable that the materials used for both toners and the blending ratio thereof be the same or approximate.

In this embodiment, an image forming apparatus using a tandem intermediate transfer belt has been described. However, the present invention is not limited to such an image forming apparatus. For example, a so-called rotary image is used. Of course, the present invention can also be applied to other general image forming apparatuses including an intermediate transfer member such as a forming apparatus.
In this embodiment, a four-color image forming apparatus using four color toners of Y, M, C, and K has been described. However, the configuration of the present invention has three colors that do not use black toner. The present invention can be applied to a color image forming apparatus without any problem.

[Verification test]
Here, the result of a verification test for verifying the effect of the present invention using an image forming apparatus (see FIG. 1) having the configuration of the present embodiment will be described. In this verification test, only the color toners of three colors Y (yellow), M (magenta), and C (cyan) are filled, the K (black) toner is not filled, and the color image layer forming unit 5K was not activated. Therefore, as for the black color, so-called process black, which is a tertiary color formed by stacking three color toners of Y (yellow), M (magenta), and C (cyan), is formed.

  In this verification test, the developer contained in the developing device 523P or the foaming toner cartridge 6P in the foaming toner layer forming unit (foaming toner image forming means) 5P includes the following thermally foamable toner and a carrier for foaming toner. A two-component developer (mixing ratio; toner: carrier = 20: 80 (mass ratio)) was used.

(Thermal foaming toner)
・ Binder resin (polyester resin): 70% by mass
・ Foaming agent (Expansel 051, manufactured by Expancel): 25% by mass
・ Wax (polyethylene resin): 5% by mass
A heat-expandable toner having a volume average particle diameter of about 25 μm and a shape factor SF-1 of 103 produced by a suspension polymerization method, depending on the raw materials and the blending ratio.

(Carrier for foamed toner)
A carrier having an average particle diameter of about 100 μm, wherein a ferrite core is coated with 0.25% by mass of an acrylic resin having a fluorine-containing group and an amino group.

  Further, as a developer housed in the developing device 523T or the transparent toner cartridge 6T in the transparent toner layer forming unit (transparent toner image forming means) 5T, a two-component developer (mixing ratio) comprising the following transparent toner and a transparent toner carrier is used. Toner: carrier = 8: 92 (mass ratio) was used.

(Transparent toner)
・ Binder resin (polyester resin): 95% by mass
・ Wax (polyethylene resin): 5% by mass
A toner having a volume average particle diameter of 7 μm and a shape factor SF-1 of 110 manufactured by an interfacial polymerization method, depending on the raw materials and the mixing ratio.

(Transparent toner carrier)
A carrier having an average particle diameter of about 35 μm, in which a ferrite core is coated with 0.1 mass% of an acrylic resin having a fluorine-containing group and an amino group.

  Further, as the developer accommodated in the developing devices 523 (Y to C) or the color toner cartridges 6Y to 6C in the color image layer forming units (color toner image forming means) 5Y, 5M, and 5C, the following color toners and color toners are used. A two-component developer (mixing ratio; toner: carrier = 8: 92 (mass ratio)) composed of a carrier for use was used.

(Color toner)
・ Binder resin (polyester resin): 88% by mass
・ Coloring material (* see below): 7% by mass
* Color material yellow toner Y ... C.I. I. Pigment Yellow 17
Magenta Toner M ... C.I. I. Pigment Red 48: 1
Cyan toner C... I. Pigment Blue 15: 1
・ Wax (polyethylene resin): 5% by mass
A toner having a volume average particle diameter of 7 μm and a shape factor SF-1 of 110 manufactured by an interfacial polymerization method, depending on the raw materials and the mixing ratio.

(Carrier for color toner)
The same carrier as the transparent toner carrier was used.

  Each surface of the photosensitive drums 52Y, 52M, 52C, 52K, 52T, and 52P is uniformly charged to a charging potential of about −700 V by a charger 521 (TP), and then a color toner image and a transparent toner image. And the part which should form a three-dimensional image is exposed with the laser writing apparatus not shown, respectively, and the electrostatic potential image whose electric potential of an exposed part is about -300V is formed.

The transparent toner T in the developing device 523T and the color toners of the colors Y, M, and C in the developing device 523 (Y to C) each have a charge amount of about −40 μC / g, and the developing bias is about − It was 600V.
In contrast, the charge amount of the thermally foamable toner P in the developing device 523P was about −4 μC / g, and the developing bias was about −600V.

According to the color information of the image, the transparent toner T is superimposed on the region where the heat-foamable toner is formed, for example, as shown in FIG. This processing may be performed by software included in the computer or may be performed by software inside the image output apparatus.
Transfer to the intermediate transfer belt 23 is performed in the order of T, Y, M, C, and P as described above. Thereafter, multiple transfer (secondary transfer) is performed on the recording paper (recording medium S) at the secondary transfer portion (secondary transfer device 24). As described above, the foamed toner layer P, the color toner layers K, C, M, and Y, and the transparent toner layer T are formed on the recording paper surface in this order from the paper side.

  In the above apparatus configuration or apparatus conditions, "thermal foaming toner alone", "thermal foaming toner + primary color", "thermal foaming toner + tertiary color", "primary color only" and "tertiary color only" are included. I actually formed the image. At that time, image formation was performed by appropriately changing the transfer application voltage at the secondary transfer site, and the transfer efficiency from the intermediate transfer belt 23 to the recording medium S was confirmed.

  Here, the primary color is a case where an amount of toner corresponding to a solid image of one color among transparent, Y, M, and C color toners is transferred, and the tertiary color is transparent, Y, M, and C. This is a case where an amount of toner corresponding to a solid image for three colors is transferred. In this verification test, the primary color in “thermally foamable toner + primary color” is formed by forming only a transparent toner layer, and the “primary color only” is formed by forming only Y color toner. “Including heat-foamable toner + tertiary color”), so-called process black in which all color toners of Y, M, and C were formed was employed.

In this verification test, the transfer efficiency is defined as satisfying the following expression when the toner mass per unit area before transfer on the intermediate transfer belt is M1 and the toner mass per unit area after transfer is M2. .
[Transfer rate (%)] = (M1-M2) / M2 × 100 (%)
The results are shown graphically in FIG. In this apparatus, in the case of color toner, since the transfer application voltage is about 2 to 3 kV, the transfer efficiency within the range is verified.

  As can be seen from the graph shown in FIG. 7, the transfer efficiency is higher when the transparent applied toner is superimposed on the thermally foamable toner even when the transfer applied voltage is higher than in the case of “thermally foamable toner alone”. It can be seen that the transfer efficiency is high because the transfer efficiency can be maintained over a wide transfer voltage range.

  In the portion where the foamed toner layer is formed, there is no significant difference in transfer efficiency between the case where the toner layer to be superimposed is “primary color” and the case of “tertiary color”. It can be seen from the graph shown in FIG. 7 that it is only necessary to form the region “single”. However, in order to more accurately match the transfer efficiency, the total toner amount of the color toner and the transparent toner is always leveled as much as possible for the portion where the heat-foamable toner exists, that is, as described above. As described above, the toner amount of the color toner image and the transparent toner image is made uniform so that the toner amount of the color toner image and the transparent toner image is more than twice or three times the amount of toner when the solid color image is formed by the color toner image forming unit. In addition, it is desirable to form a transparent toner image by adjusting the toner amount.

1 is a schematic configuration diagram schematically illustrating a schematic configuration of a stereoscopic image forming apparatus according to an embodiment which is an exemplary aspect of the present invention. 3 is a schematic cross-sectional view illustrating an example of a surface state of a recording medium when a transparent toner layer is not formed. FIG. FIG. 4 is a schematic cross-sectional view showing a state where a transparent toner layer, a color toner layer, and a foamed toner layer are transferred and formed on the surface of an intermediate transfer belt. FIG. 4 is a schematic cross-sectional view in which only a region (3) in FIG. 3 is extracted and enlarged, and a foamed toner layer is not shown. The total toner amount of the color toner image and the transparent toner image with respect to the region (3) in FIG. 2 is twice the toner amount when the single color solid image is formed by the color toner image forming unit. It is a schematic cross-sectional view showing a state in which a transparent toner image is formed. FIG. 3 is a schematic cross-sectional view showing a state in which a transparent toner image is formed so that the total toner amount of the color toner image and the transparent toner image is uniform with respect to the region (3) in FIG. It is a graph which shows the result of a verification test, a horizontal axis is transfer application voltage, and a vertical axis is transfer efficiency from an intermediate transfer belt to a recording medium.

Explanation of symbols

  2: platen cover, 3: document reading device, 5: image forming unit, 5T: transparent toner image forming unit (transparent toner image forming means), 5Y, 5M, 5C, 5K: color toner image forming unit (color toner image forming) Means), 5P: foamed toner image forming unit (foamed toner image forming means), 6: toner cartridge, 7: sheet supply tray, 10: three-dimensional image forming apparatus, 23: intermediate transfer belt (intermediate transfer member), 24: two Next transfer device (transfer means), 25: Fixing device (fixing means), 50: Personal computer, 52: Photosensitive drum, 241: Backup roll, 242: Secondary transfer roll, 251: Pressure roll, 252: Heating roll 521: charger, 523: developing device, 524: primary transfer device, 525: cleaner

Claims (6)

Color toner image forming means for forming a color toner image by laminating three or more color toners, foamed toner image forming means for forming a foamed toner image with a thermally foamable toner, the color toner image and the foamed toner An intermediate transfer member in which a color foamed toner image is formed by laminating the image on the surface, a transfer means for transferring the color foamed toner image on the surface of the intermediate transfer member to the surface of the recording medium, and a transfer to the surface of the recording medium A three-dimensional image forming apparatus comprising: a fixing unit that applies at least heat to the color foamed toner image that has been foamed and fixed;
Further, prior to the formation of the foamed toner image by the foamed toner image forming means, the transparent toner image forming means for forming a transparent toner image by the transparent toner, and
The three-dimensional image forming apparatus, wherein the transparent toner image forming means is a means for forming a transparent toner image on a portion of the color foamed toner image on the surface of the intermediate transfer member where the foamed toner image is formed. Color toner image forming means for forming a color toner image by laminating three or more color toners, foamed toner image forming means for forming a foamed toner image with a thermally foamable toner, the color toner image and the foamed toner Transfer means for transferring the color foamed toner image onto the surface of the recording medium on the paper conveying belt by laminating the image on the surface; and applying at least heat to the color foamed toner image transferred to the surface of the recording medium to cause foaming; A fixing means for fixing, and a stereoscopic image forming apparatus comprising:
Further, prior to the formation of the foamed toner image by the foamed toner image forming means, the transparent toner image forming means for forming a transparent toner image by the transparent toner, and
The three-dimensional image formation characterized in that the transparent toner image forming means is a means for forming a transparent toner image on a portion of the color foamed toner image of the recording medium on the paper conveying belt to which the foamed toner image is transferred. apparatus. The three-dimensional image forming apparatus according to claim 1 or 2, wherein the transparent toner used in the transparent toner image forming unit has substantially the same particle diameter as the color toner used in the color toner image forming unit. The three-dimensional image forming apparatus according to claim 1, wherein the transparent toner used in the transparent toner image forming unit has substantially the same charge distribution as the color toner used in the color toner image forming unit. The three-dimensional image forming apparatus according to claim 1, wherein the transparent toner used in the transparent toner image forming unit has substantially the same shape as the color toner used in the color toner image forming unit. In the transparent toner image forming means, the total toner amount of the color toner image and the transparent toner image is uniform in the portion where the foamed toner image is formed in the color foamed toner image on the surface of the intermediate transfer member. The three-dimensional image forming apparatus according to claim 1, wherein a transparent toner image is formed.

Images