JP6900650B2 - Image forming device and image forming method - Google Patents

Description

The present invention relates to an image forming apparatus and an image forming method.

Conventionally, an electrophotographic image forming apparatus for forming an image using toner has been known (see, for example, Patent Document 1 and the like). In this technique, the toner image obtained by developing the electrostatic latent image on the photoconductor is primarily transferred to the intermediate transfer body, and an electric field is applied to the intermediate transfer body and the image forming object to obtain the toner image of the intermediate transfer body as the image forming object. By secondary transfer to the image, an image is formed on the image-forming object.

In order to transfer the toner image, an electric field sufficient to transfer the toner image to the toner layer on which the toner image is formed is applied. However, it may be difficult for the toner layer formed by the toner image to come into stable contact with the image-forming object during transfer, and in order to eliminate this, ultrasonic vibration is applied during transfer to stabilize and stabilize the image. A technique for contacting and transferring is known (see, for example, Patent Document 2 and the like).

Japanese Unexamined Patent Publication No. 2000-221780 Japanese Unexamined Patent Publication No. 10-43670

By the way, in recent years, an image forming technique using powder particles instead of toner has a small amount of volatile organic compounds (VOC) emitted, and powder particles that have not been used for image forming can be recovered and reused. Therefore, it is attracting attention in terms of the global environment. Further, the image forming apparatus is not limited to a recording material such as paper, and it is desired to form an image on various image forming objects, but for an image forming object having high insulation property. When forming an image, it may be difficult to form an image because the electric field is attenuated in the object to be formed.
INDUSTRIAL APPLICABILITY The present invention is an image forming apparatus capable of forming an image by suppressing attenuation of an electric field in an image forming object as compared with forming an image using charged particles without considering the conductivity of the image forming object. And an image forming method.

In order to achieve the above object, the image forming apparatus of the first aspect supplies a conductive material to an image forming object in which a larger electric field is required as the thickness increases when charged particles are attached. A conductive layer forming portion that forms a conductive layer, an image forming portion that forms an image by transferring a charged particle image formed of charged particles to the conductive layer of the image forming object, and the conductive layer. and a deposition unit for depositing the charged particle image formed by the charged particle image of a polarity opposite the charged particles voltage by applying to said conductive layer.

A second aspect is the image forming apparatus according to the first aspect , wherein the conductive layer forming portion is a main surface of the plate-shaped member including an image forming surface for forming the image on the image forming object of the plate-shaped member. Is provided with the conductive layer, and the conductive layer is provided on a surface other than the main surface of the plate-shaped member that is continuous with the main surface of the plate-shaped member .

A third aspect includes a first transport unit for transporting the image-forming object in the image forming apparatus according to the first or second aspect, and transports the first transport unit after forming the charged particle image. A particle cleaning unit for cleaning the particles remaining in the first transport unit is provided on the downstream side in the direction.

A fourth aspect is the image forming apparatus according to the third aspect , wherein the first conveying portion includes a conveying belt, and the conveying belt is a fixing portion for fixing the image forming object on the conveying belt during conveying. including.

A fifth aspect is the image forming apparatus according to the fourth aspect , wherein the transport belt has a plurality of perforations, and the fixing portion fixes the image forming object through the plurality of perforations by a suction device. To do .

The sixth aspect includes a demolding portion that demolds the conductive layer formed by the conductive layer forming portion in the image forming apparatus according to the fifth aspect so as to have a predetermined releasability. ..

A seventh aspect is the image forming apparatus according to the sixth aspect , wherein the conductive layer forming portion includes a second conveying portion that conveys an image forming object before forming the conductive layer, and the image forming portion and the conductive layer. The layer forming portion is provided at a position separated by a predetermined distance.

In the eighth aspect , in the image forming apparatus according to the seventh aspect , a conductive material cleaning section for cleaning the conductive material remaining in the second transport section is included on the downstream side in the transport direction of the second transport section.

A ninth aspect is the image forming apparatus according to any one of the eighth aspect of the first aspect, wherein the particles comprise powder particles having a heat-curable, are attached to the conductive layer by the image forming section Includes a heat-fixing portion that heat-fixes the charged particle image.

In the image forming method of the tenth aspect , a conductive material is supplied to form a conductive layer on an image forming object that requires a larger electric field as the thickness increases when particles are attached, and the image forming object is formed. An image of charged particles formed of charged particles is transferred to the conductive layer to form an image, and a voltage having a polarity opposite to that of the charged particle image is applied to the conductive layer to apply the charged particles. The image of the charged particles formed in (1) is attached to the conductive layer.

According to the first aspect and the tenth aspect , the attenuation of the electric field in the image forming object is suppressed as compared with the case where the image is formed by using the charged particles without considering the conductivity in the image forming object. The image can be formed.
According to the second aspect , the charged particles can easily apply a voltage having a polarity opposite to that of the image, as compared with the case where the surface forming the plate-shaped member is not considered.
According to the third aspect , it is possible to suppress the influence of the remaining particles and electric charges on the next image formation as compared with the case where the particles remaining in the image transporting portion are not cleaned and statically removed after the charged particle image formation.
According to the fourth aspect , it is possible to suppress a decrease in image formation accuracy due to the movement of the image forming object as compared with the case where the image forming object is not fixed to the transport belt.

Further, according to the above-described aspect , as compared with the case where the conductive layer forming portion for forming the conductive layer is not provided, the productivity is improved regardless of the conductivity of the image forming object, and the attenuation of the electric field in the image forming object is reduced. The image can be formed by suppressing it.
According to the sixth aspect , it is possible to suppress the deterioration of image quality caused by the state of the conductive layer that has not been demolded, as compared with the case where the demolding portion is not provided.
According to the seventh aspect , image quality deterioration due to the influence of residual particles during the formation of the conductive layer can be suppressed as compared with the case where the transfer of the image-forming object is not made independent between the image formation and the formation of the conductive layer.
According to the eighth aspect , the influence of the residual particles on the next formation of the conductive layer can be suppressed as compared with the case where the residual particles at the time of forming the conductive layer are not cleaned.
According to the ninth aspect , the image can be easily fixed as compared with the case where the thermosetting powder particles are not used.

It is the schematic which shows an example of the structure of the image forming apparatus which concerns on this embodiment. It is an image figure which shows an example of the conductive layer which concerns on this embodiment. It is a characteristic diagram which shows an example of the thickness of the insulating layer and the applied electric field which concerns on this embodiment. It is the schematic which shows an example of the structure of the image forming part which concerns on this embodiment. It is an image figure which shows an example of the structure of the transport belt which concerns on this embodiment. It is the schematic which shows an example of the structure of the development unit which concerns on this embodiment. It is a side sectional view which shows an example of the structure of the developer of the two-component developing system which concerns on this embodiment. It is a side sectional view which shows an example of the structure of the developer of the one-component developing type which concerns on this embodiment. It is an image figure which shows an example of the power feeding part which concerns on this embodiment. It is an image figure which shows an example of the power feeding part which concerns on this embodiment. It is explanatory drawing concerning the transfer of the image forming apparatus which concerns on this embodiment. It is a block diagram which shows an example of the image formation control part which concerns on this embodiment. It is a flowchart which shows an example of the flow of the process executed by the image formation control unit which concerns on this embodiment.

Hereinafter, an example of the image forming apparatus according to the embodiment of the present invention will be described in detail with reference to the drawings. It should be noted that components and processes having the same function and function may be given the same code throughout the drawings, and duplicate explanations may be omitted as appropriate.

<Image forming device>
FIG. 1 shows an example of the configuration of the image forming apparatus 10 according to the present embodiment.

The image forming apparatus 10 according to the present embodiment is an image forming unit 12 for forming an image (powder particle image) of powder particles on a recording medium MD by using an electrophotographic method, and powder particles formed on the recording medium MD. A heat fixing portion 14 for heating and fixing the image is provided. Further, a conductive layer forming portion 16 and a conductive layer stabilizing portion 18 are provided on the upstream side of the recording medium MD in the transport direction.

Examples of the recording medium MD as an image forming object that can be used in the image forming apparatus 10 according to the present embodiment include a plate-like body made of metal, ceramic, or resin. In the present embodiment, the recording medium MD preferably has at least an image-forming surface having conductivity from the viewpoint of electrostatically adhering powder particles in the image-forming unit 12. Here, the conductivity means, for example, a volume resistivity of 1013 Ωcm or less.

In the present embodiment, the image forming unit 12 can form an image (powder particle image) of powder particles on the recording medium MD regardless of the presence or absence of conductivity of the recording medium MD. A conductive layer forming portion 16 and a conductive layer stabilizing portion 18 are provided on the upstream side in the transport direction to form the conductive layer on the recording medium MD.

Then, as will be described in detail later, when the image forming unit 12 forms the powder particle image on the recording medium MD with the powder particles, the recording medium MD (specifically, from the viewpoint of electrostatically adhering the powder particles). The voltage is applied to the recording medium MD or the recording medium MD is grounded so that the polarity of the image forming surface) is opposite to the polarity of the charged powder particles.

When a metal plate-like body such as a conductive steel plate or a conductive plate-like body in which a conductive layer is previously provided on the surface of a non-metallic material is used as the recording medium MD, the conductive layer forming portion 16 And the process of forming the conductive layer in the conductive layer stabilizing portion 18 may be omitted, and the recording medium MD may be conveyed to the image forming portion 12.

(Conductive layer forming part)
As shown in FIG. 1, the conductive layer forming unit 16 is provided on the upstream side of the image forming unit 12 in the transport direction of the recording medium MD, and is a processing unit for forming the conductive layer Ep on the recording medium MD. The conductive layer forming portion 16 includes a conductive material coating portion 16-1 that forms a conductive layer Ep by applying a conductive material to at least the image forming surface (main surface) of the recording medium MD. As an example of the treatment of forming the conductive layer Ep on the image forming surface of the recording medium MD in the conductive material coating portion 16-1, the surface such as a primer treatment for applying a primer containing a conductive material, a metal plating treatment, and electrodeposition coating. Processing can be mentioned. Further, as another example of the treatment for forming the conductive layer Ep, there is a coating treatment for applying thermosetting conductive particles.

Further, the conductive layer forming portion 16 includes a conveying portion 17 that conveys the recording medium MD. The transport unit 17 includes a transport roller 17A and a transport belt 17B wound around the transport roller 17A, and transports the recording medium MD by moving the transport belt 17B by rotationally driving the transport roller 17A.

Further, the conductive layer forming portion 16 includes a transport body cleaning portion 16-2. After forming the conductive layer Ep on the recording medium MD, the transport body cleaning unit 16-2 cleans the conductive material remaining on the transport belt 17B of the transport unit 17.

FIG. 2 shows an example of the conductive layer Ep formed on the recording medium MD in the conductive layer forming portion 16.
FIG. 2A shows an example of the recorded recording medium MD being conveyed. FIG. 2B shows an example of the conductive layer Ep formed on the image forming surface (main surface) of the recording medium MD. Further, FIG. 2C shows an example of a conductive layer Ep further formed on a side surface continuous with the image forming surface (main surface) of the recording medium MD, and FIG. 2D shows recording. An example of the conductive layer Ep formed on another surface (another main surface) continuous with the side surface of the medium MD is shown. The formed conductive layer Ep is preferably formed to have a uniform thickness.

Therefore, even if the recording medium MD is an insulating material, the conductive layer Ep can be formed on the recording medium MD in the conductive layer forming portion 16, and an electric field is applied to the recording medium MD as described in detail later. it can.

That is, in the image forming apparatus 10, when the image forming unit 12 forms the powder particle image on the recording medium MD by the powder particles, an electric field is applied to electrostatically attach the powder particles (for details, refer to the details. See below). However, when the recording medium MD has high insulating properties, a larger electric field is applied to attach (transfer) the charged powder particles to the recording medium MD.

FIG. 3 shows an example of an electric field applied to the insulating recording medium MD.
In FIG. 3, the vertical axis is the electric field (applied voltage: voltage applied at the time of transfer) applied at the time of transfer of the powder particle image formed by the image forming unit 12 to the recording medium MD, and the thickness of the recording medium MD is horizontal. As the axis, the applied voltage characteristic with respect to the thickness of the recording medium MD is shown by a curve Ld. In the example of FIG. 3, the case where the applied voltage is doubled in order in eight steps is shown as curves Ld1 to Ld8. That is, the curves Ld1 to Ld8 have larger applied voltages in order (Ld1 <Ld2 = 2, Ld1 <Ld3 = 3, Ld1 <Ld4 = 4, Ld1 <Ld5 = 5, Ld1 <Ld6 = 6, Ld1 <Ld7 = 7). -Ld1 <Ld8 = 8-Ld1) is set.

As shown in FIG. 3, as the thickness of the recording medium MD increases, the applied voltage during transfer increases. For this reason, as the thickness of the recording medium MD increases, a larger transfer voltage is required, and it is required to increase the size of the device and the capacity of the power supply device. However, even if a larger transfer voltage is applied, the effect on the electric field is small. On the other hand, when the recording medium MD is thick and a sufficient transfer voltage is not applied, image unevenness occurs due to transfer failure in which the transfer efficiency is deteriorated. Therefore, in the present embodiment, in order to enable the image forming unit 12 to form a powder particle image on the recording medium MD regardless of the presence or absence of conductivity of the recording medium MD, that is, the insulating property, the conductive layer forming unit No. 16 is configured to form a conductive layer on the recording medium MD.

The conductive layer forming portion 16 of the present embodiment is an example of the conductive layer forming portion of the present invention. Further, the transport unit 17 is an example of the second transport unit of the present invention, and the transport body cleaning unit 16-2 is an example of the conductive material cleaning unit of the present invention.

(Conductive layer stabilizing part)
As shown in FIG. 1, the conductive layer stabilizing portion 18 is provided on the downstream side of the conductive layer forming portion 16 in the transport direction of the recording medium MD and on the upstream side of the image forming portion 12 in the transport direction of the recording medium MD. This is a processing unit that stabilizes the conductive layer Ep formed on the recording medium MD on the recording medium MD. The conductive layer stabilizing unit 18 includes a mold release unit 18-1, a cooling unit 18-2, and a carrier cleaning unit 18-3. Further, the conductive layer stabilizing unit 18 includes a transport unit 19 that conveys the recording medium MD. The transport unit 19 includes a transport roller 19A and a transport belt 19B wound around the transport roller 19A, and transports the recording medium MD by moving the transport belt 19B by rotationally driving the transport roller 19A.

The demolding unit 18-1 is a functional unit that performs a process of improving the releasability of the conductive layer Ep formed on the image forming surface of the recording medium MD by the conductive layer forming unit 16. In the present embodiment, the releasability does not mean the property of indicating the ease of separation between the conductive layer Ep and the recording medium MD, but the stability of the conductive layer Ep. For example, the stability of the conductive layer Ep can be expressed by a state such as the viscosity of the surface of the conductive layer Ep in contact with the outside. That is, when the conductive layer Ep is formed of a wet conductive material, it has viscosity until it reaches a dry state, and articles are likely to adhere to the surface of the conductive layer Ep, and it is considered that the stability is low. .. Therefore, in order to improve the releasability, that is, the stability, for example, the conductive layer Ep is dried in a high temperature environment to make it difficult for articles to adhere to the conductive layer Ep, and the conductive layer Ep is stabilized on the recording medium MD. Therefore, the stability of the conductive layer Ep can be rephrased as a property showing a viscous state in which it is difficult for the article to adhere to the surface of the conductive layer Ep. As a result, the releasability increases as the degree of drying increases. Further, the stability of the conductive layer Ep can be expressed by, for example, the structural state of the conductive layer Ep. That is, when the conductive layer Ep is formed by placing a material such as thermosetting conductive particles on it, it is in a state where it easily loses its shape until it reaches a fixed state, and it is considered that the stability is low. Therefore, in order to improve the releasability, that is, to improve the stability, for example, the conductive layer Ep is heated until it reaches a fixed state to stabilize the conductive layer Ep on the recording medium MD. Therefore, the stability of the conductive layer Ep can be rephrased as the property that the conductive layer Ep is hard to lose its shape. As a result, the mold releasability increases as the degree of shape loss (for example, hardness) due to heating increases. Therefore, in the present embodiment, in order to improve the releasability, for example, the conductive layer Ep surface is dried until it reaches a dry state or heated until it reaches a fixed state to stabilize the conductive layer Ep on the recording medium MD.

In the present embodiment, a case where the mold releasability is improved by drying the conductive layer Ep will be described as an example. That is, the mold release unit 18-1 includes a dryer, and the conductive layer Ep is dried in a high temperature environment by the dryer to improve the mold releasability of the conductive layer Ep. Specifically, the mold release unit 18-1 is provided with a heat source 18-1, and is arranged so as to face the conductive layer Ep formed on the image forming surface of the recording medium MD to be conveyed. Examples of the heat source 18-1 include known heat sources such as halogen lamps, ceramic heaters, and infrared lamps. Further, as another example of the heat source, a laser irradiation device that irradiates an infrared laser to heat the powder particle layer may be used.

The conductive layer stabilizing portion 18 and the demolding portion 18-1 of the present embodiment are examples of the demolding portion of the present invention.

(Image forming part)
As shown in FIG. 1, the image forming section 12 is provided on the downstream side of the conductive layer forming section 16 and the conductive layer stabilizing section 18 in the transport direction of the recording medium MD, and an electrophotographic method is used for the recording medium MD. This is a processing unit that forms an image by laminating powder particle images of powder particles in multiple layers. A recording medium MD having a conductive layer Ep formed by the conductive layer forming portion 16 and stabilized by the conductive layer stabilizing portion 18 is carried into the image forming portion 12. The image forming unit 12 is equipped with a multi-layer forming function that receives various data via the communication unit 64 (see FIG. 12) and performs a multi-layer forming process on the recording medium MD based on the received data.

FIG. 4 shows an example of the configuration of the image forming unit 12 according to the present embodiment. The image forming unit 12 includes a conveying unit 54 that conveys the recording medium MD. The transport unit 54 includes a transport roller 54A and a transport belt 54B wound around the transport roller 54A, and transports the recording medium MD by moving the transport belt 54B by rotationally driving the transport roller 54A.

The image forming unit 12 forms an image by stacking powder particle images in multiple layers and transferring them to a recording medium MD. Therefore, when the stacked powder particle images are transferred, the position shift of the recording medium MD affects the quality of the image. That is, if the recording medium MD is misaligned on the transport belt 54B during the transfer of the powder particle image, the image quality may deteriorate. Therefore, in the present embodiment, the recording medium MD is fixed on the transport belt 54B to suppress the misalignment of the recording medium MD that occurs on the transport belt 54B.

FIG. 5 shows an example of the configuration of the transport belt 54B that suppresses the misalignment of the recording medium MD.
As shown in FIG. 5, the transport belt 54B has a plurality of perforations 54C on one surface. A suction device (not shown) is communicated with the plurality of perforations 54C, and the recording medium MD placed on the transport belt 54B is sucked, and the recording medium MD is being transported by the transport belt 54B. Is fixed on the transport belt 54B. As a result, the positional deviation that occurs in the recording medium MD on the transport belt 54B can be suppressed, and the deterioration of image quality can be suppressed.

In the following description, the image forming unit 12 is a multicolored four-color image in which black (black) is added to three colors of yellow, magenta, and cyan for each layer formed by laminating multiple layers on the recording medium MD. The case where the image forming process is performed will be described, but the colors used for the color image forming process are not limited to four colors. For example, a plurality of colors such as white may be used in which one or more different colors are added to the three colors of yellow, magenta, and cyan. Further, two or more of the four colors of yellow, magenta, cyan and white may be the same color with any one of yellow, magenta, cyan and white or another color. Moreover, you may use clear (transparent color).

Further, regarding the colors, each of yellow, magenta, cyan, and black will be described by notating them with alphabetic characters (color codes) of Y, M, C, and K. Further, when distinguishing each color of yellow, magenta, cyan, and black in the constituent elements of the image forming apparatus 10, the letters Y, M, C, and K (color codes) are added after the numbers. When it is not necessary to distinguish each color, the letters Y, M, C and K (color code) after the number are omitted.

The image forming unit 12 includes a developing unit 20 for each of the colors Y, M, C, and K. Further, the image forming unit 12 is provided with a primary transfer device 30 corresponding to each of the development units 20 for each of Y, M, C, and K colors.

FIG. 6 shows an example of a schematic side sectional view showing a main part configuration of the developing unit 20.
The developing unit 20 includes a photoconductor 21 as an image holder that rotates in the direction of arrow A, a charger 22, an exposure unit 23, and a developer 24. Further, the photoconductor 21 of the developing unit 20 is arranged to face the primary transfer device 30, and the intermediate transfer belt 32 is located between the photoconductor 21 and the primary transfer device 30.

The charger 22 charges the surface of each photoconductor 21 by applying a charging bias. The exposure unit 23 exposes the surface of the charged photoconductor 21 with exposure light modulated based on the image information of each color, and forms an electrostatic latent image on the photoconductor 21. The developing device 24 includes a developing roll 240 that holds a developing agent (powder particles) of each color. The developer 24 develops an electrostatic latent image on the photoconductor 21 with powder particles of each color by applying a development bias to the developing roll 240 with a development bias power supply (not shown), and powders on the photoconductor 21. Form a particle image.

Then, the powder particle image formed on the photoconductor 21 is transferred to the intermediate transfer belt 32 by the primary transfer device 30.

The developing unit 20 includes a cleaning device 25 including a cleaner for cleaning the surface of the photoconductor 21 and a static eliminator for removing residual charges on the surface of the photoconductor 21.

The developer 24 of the developing unit 20 in the image forming apparatus 10 according to the present embodiment will be described. In the present embodiment, the developing unit 20 is arranged so that powder particle images of each color of Y, M, C, and K are laminated on the intermediate transfer belt 32 in the order of Y, M, C, and K. Therefore, in the present embodiment, the powder particle images of each color of Y, M, C, and K are laminated on the intermediate transfer belt 32 in the order of Y, M, C, and K. Further, in the present embodiment, as the developer 24 for each color of Y, M, C, and K, a developer of a two-component developing method may be used, or a developer of a non-magnetic one-component developing method may be used.

FIG. 7 shows an example of a schematic side sectional view showing a main part configuration of a two-component developing method developer 24Y for Y color. In the present embodiment, the Y, M, C, and K color developing devices 24Y, 24M, 24C, and 24K are configured in the same manner. Therefore, the Y color developing device 24Y will be described here, and other developing devices will be described. The description of 24M, 24C, and 24K will be omitted.

As shown in FIG. 7, the Y-color developer 24Y includes a developing roll 240Y, a first stirring member 241Y, a second stirring member 242Y, and a particle layer regulating member 243Y. In the Y-color developer 24Y, the non-magnetic one-component particles (non-magnetic one-component developer) are placed on the developing roll 240Y, and the powder particles are placed on the surface of the developing roll 240Y by the first stirring member 241Y and the second stirring member 242Y. It is supplied to form a powder particle layer by the particle layer regulating member 243Y, and after charging the powder particles, the powder particles are attached to an electrostatic latent image on the surface of the photoconductor 21Y for development. That is, the developer mixed with the powder particles by the second stirring member 242Y moves to the side of the first stirring member 241Y, and while being stirred by the first stirring member 241Y, the powder particles magnetic force on the surface of the developing roll 240Y. Is attached by. Then, the developer is conveyed to the photoconductor 21Y side by the developing roll 240Y from the direction opposite to the rotation direction of the photoconductor 21Y to develop the electrostatic latent image of the photoconductor 21Y. As the developing unit of the non-magnetic one-component developing method, a well-known device (see, for example, Japanese Patent Application Laid-Open No. 2006-911183) may be adopted.

In the present embodiment, the case where the developer 24 of the two-component developing method is used will be described, but the developer of the non-magnetic one-component developing method may be used.
FIG. 8 shows, as an example, a schematic side view of a main part configuration when a non-magnetic one-component developing method developer is used as the K-color developing device 24K.

As shown in FIG. 8, in the image forming apparatus 10, a non-magnetic one-component developing type developing apparatus is applied to the developing device 24K of the developing unit 20K for developing black (K) powder particles. The non-magnetic one-component development type developer 24K develops powder particles by, for example, a particle supply roller 244K adjacent to the development roll 240K and a stirring member 245K for non-magnetic one-component particles (non-magnetic one-component developer). It is supplied to the surface of 240K to form a K-colored powder particle layer by the particle layer regulating member 243K, and after charging the K-colored powder particles, the powder particles are added to the electrostatic charge image on the surface of the photoconductor 21K. It is a developing unit of a method of adhering and developing. A well-known device (see, for example, Japanese Patent Application Laid-Open No. 2003-76120) may be used as the developing unit of the non-magnetic one-component developing method.

As shown in FIG. 4, the image forming unit 12 includes a secondary transfer device 40 that transfers the powder particle image on the intermediate transfer belt 32 to the recording medium MD. The secondary transfer device 40 faces the backup roll 42, which conveys the intermediate transfer belt 32 together with the rollers 34 and 35 by a motor (not shown) while stretching the intermediate transfer belt 32, and sandwiches the intermediate transfer belt 32 and the transfer belt 54B. It is provided with a secondary transfer roll 44 provided at the position. That is, the intermediate transfer belt 32 and the transfer belt 54B are transferred to the gap between the backup roll 42 of the secondary transfer device 40 and the secondary transfer roll 44 (hereinafter referred to as a roll pair). That is, the secondary transfer roll 44 is provided at a position facing the backup roll 42 via the transport belt 54B which is transported while being stretched by the transport roller 54A.

A voltage (or current) is applied to the roll pair of the secondary transfer device 40 from the secondary transfer power supply 46, and the applied voltage can be adjusted by a transfer control unit (not shown). The negative electrode of the secondary transfer power supply 46 is connected to the ground potential (for example, 0V), and the positive electrode is connected to the metal shaft of the backup roll 42. The metal shaft of the backup roll 42 is also connected to the ground potential (for example, 0V).

The backup roll 42 is, for example, a rotatable roller having a diameter of 18 mm in which solid rubber is formed around a metal shaft having a diameter of 14 mm. The solid rubber is a conductive material whose resistance value is adjusted to 1 x 106 Ω or more and 1 x 107 Ω or less by mixing an ionic conductive agent with acrylonitrile butadiene rubber (NBR), which has excellent oil resistance, wear resistance, and aging resistance. I am using it. As an example of solid rubber, a conductive material in which NBR and epichlorohydrin rubber (ECO) are blended can also be used. Further, as another example, a conductive material made of urethane rubber in which an ionic conductive agent is mixed with rubber obtained by reacting a polyether polyol with isodianate can be used. Furthermore, as another example, a conductive material made of ethylene propylene diene rubber (EPDM) can be used. The metal shaft is connected to the ground potential (for example, 0 V).

Further, the secondary transfer roll 44 is, for example, a rotatable roller having a diameter of 18 mm in which foam rubber is formed around a metal shaft having a diameter of 12 mm. For the foam rubber, an ion conductive agent is applied to urethane having excellent cushioning properties. The foam rubber 7E is mixed and the resistance value of the foam rubber 7E is adjusted to 1 × 107Ω or more and 1 × 108Ω or less. The metal shaft is connected to the positive electrode side of the secondary transfer power supply 46.

The transfer control unit (not shown) of the secondary transfer device 40 applies the voltage of the negative electrode from the secondary transfer power supply 46 to the roll pair at the timing when the recording medium MD is conveyed to the gap formed by the roll pair.

The image forming unit 12 includes a belt cleaner 52 for cleaning the powder particles remaining on the surface of the intermediate transfer belt 32 after transferring the powder particle image to the recording medium MD. Further, the image forming apparatus 10 includes an image forming control unit 50 that controls image forming. Further, the image forming unit 12 is provided with a cleaning device 56 for removing deposits such as residual particles adhering to the surface of the transport belt 54B.

By the way, in the secondary transfer device 40, a voltage is applied from the secondary transfer power supply 46 to the roll pair (backup roll 42 and secondary transfer roll 44), but when the recording medium MD is thick and the insulation is high, the transfer voltage is high. Insufficient transfer may lead to poor transfer. In the present embodiment, a conductive layer Ep is formed on the surface of the recording medium MD, and power is supplied to the conductive layer Ep to compensate for the insufficient transfer voltage. That is, the secondary transfer device 40 according to the present embodiment includes a feeding unit 48 that applies a voltage to the conductive layer Ep formed on the surface of the recording medium MD.

FIG. 9 shows an example of an intermediate transfer belt 32 having a configuration that functions as a feeding unit 48.
In FIG. 9A, the intermediate transfer belt 32 is provided with a feeding portion 48 for supplying power to the conductive layer Ep (see FIG. 2B) formed on the image forming surface (main surface) of the recording medium MD. An example is shown. FIG. 9B shows an example of the positional relationship between the power feeding unit 48 and the conductive layer Ep formed on the recording medium MD.

As shown in FIG. 9, the feeding portion 48 is provided with the insulating layer 32-1 and the conductive layer 32-2 laminated in this order on one side edge portion in the width direction of the intermediate transfer belt 32. The conductive layer 32-2 is connected to the positive electrode side of the secondary transfer power supply 46 applied to the secondary transfer roll 44. As a result, in the secondary transfer device 40, when a voltage is applied from the secondary transfer power source 46 to the roll pair (backup roll 42 and secondary transfer roll 44), the recording medium MD is thick and has high insulation. Even if there is, the electric field can be applied between the backup roll 42 and the recording medium MD by supplying power to the conductive layer Ep on the recording medium MD, the transfer voltage shortage can be suppressed, and the transfer failure can be suppressed. ..

Here, when the feeding portion 48 is provided on the intermediate transfer belt 32 as shown in FIG. 9, a part of the image forming surface (main surface) of the recording medium MD, that is, the contact portion of the feeding portion 48 is an image forming region. Is excluded from. This is because the contact portion of the feeding portion 48 is used as a region corresponding to the electrode for particle transfer. In order to use the entire image forming surface (main surface) of the recording medium MD as an image forming region, the contact portion of the power feeding unit 48 may be set to a portion other than the image forming surface (main surface) of the recording medium MD. Good. For example, the conductive layer Ep may be further formed on the side surface continuous with the image forming surface (main surface) of the recording medium MD (see FIG. 2C).

FIG. 10 shows an example of the power feeding unit 48 that supplies power to the conductive layer Ep formed on the side surface of the recording medium MD.
As shown in FIG. 10, the feeding portion 48 includes an electrode 48A and an electrode fixing portion 48B. One end of the electrode 48A is in contact with the conductive layer Ep formed on the side surface of the recording medium MD, and the other end is connected to the electrode fixing portion 48B. The electrode fixing portion 48B is the positive electrode of the secondary transfer power supply 46. It is configured to be connected to the side. With this configuration, power can be supplied to all the conductive layers Ep formed on the image forming surface (main surface) of the recording medium MD by the electrodes 48A, and the image forming surface (main surface) of the recording medium MD can be supplied. ) Can be used as an image forming region.

Further, the conductive layer Ep may be formed on another surface (another main surface) continuous with the side surface of the recording medium MD (see FIG. 2D). In this case, the surface of the transport belt 54B may be configured to have conductivity, and power may be supplied from the surface of the transport belt 54B.

Therefore, even if the recording medium MD is an insulating material, the conductive layer forming portion 16 can supply power to the conductive layer Ep formed on the recording medium MD, and an electric field is applied to the insulating recording medium MD. Can be done.

The image forming unit 12 of the present embodiment is an example of the image forming unit of the present invention. Further, the secondary transfer device 40 and the feeding unit 48 are examples of the attachment unit of the present invention, and the transport unit 54 is an example of the first transport unit of the present invention. Further, the cleaning device 56 is an example of the particle cleaning unit of the present invention.

(Heat fixing part)
The heat fixing unit 14 shown in FIG. 1 is an image forming unit 12 and is a processing unit that heats and fixes the powder particle image transferred to the recording medium MD. The heat fixing unit 14 is configured to heat and heat-cure the powder particle layer formed on the image forming surface (conductive layer Ep) of the recording medium MD by the image forming unit 12, for example. The heat fixing unit 14 includes a heat source 14-1 for heat fixing, and the heat source 14-1 is arranged so as to face the powder particle image transferred (laminated) on the recording medium MD to be conveyed. There is. Examples of the heat source 14-1 include known heat sources such as halogen lamps, ceramic heaters, and infrared lamps. Further, as another example of the heat source 14-1, a laser irradiation device that irradiates an infrared laser to heat the powder particle layer may be used.

The heat-fixing portion 14 of the present embodiment is an example of the heat-fixing portion of the present invention.

<Outline of image formation operation>
Next, an outline of the image forming operation in the image forming apparatus 10 according to the present embodiment will be described.

First, the original image information of the image forming target is output to the image forming apparatus 10 from a terminal device such as a personal computer (not shown) via a communication line (not shown). When the original image information is input to the image forming apparatus 10, the image forming apparatus 10 forms the conductive layer Ep on the recording medium MD at the conductive material coating portion 16-1 of the conductive layer forming portion 16 (see FIG. 2). .. The recording medium MD on which the conductive layer Ep is formed is carried out to the conductive layer stabilizing portion 18 by driving the conveying portion 17, and the conductive layer Ep is formed by, for example, drying in the demolding portion 18-1 of the conductive layer stabilizing portion 18. Be stabilized. The recording medium MD in which the conductive layer Ep is stabilized is, for example, cooled by the cooling unit 18-3 in order to lower the temperature raised by drying, and then carried out to the image forming unit 12 by the drive of the transport unit 19. Then, the image forming apparatus 10 applies a charging bias to the charging device 22 to charge the surface of the photoconductor 21 to the negative electrode.

In the conductive layer forming unit 16, after the conductive layer Ep is formed on the recording medium MD, the conductive material remaining on the transport belt 17B is cleaned by the transport body cleaning unit 16-2, and the transport belt 17B is always clean. Keep in state. Further, the conductive layer stabilizing portion 18 also cleans the conductive material remaining on the transport belt 19B by the transport body cleaning unit 18-2, and keeps the transport belt 19B in a clean state at all times.

On the other hand, the original image information is input to the image formation control unit 50. The image formation control unit 50 decomposes the original image information into image data of each color of YMCK, and then outputs a modulation signal based on the image data of each color to the exposure unit 23 of the corresponding color. The exposure unit 23 outputs a laser beam modulated according to the input modulation signal. The modulated laser beam irradiates the surface of the photoconductor 21. The surface of the photoconductor 21 is in a state where the negative electrode is charged by the charger 22, and when the surface of the photoconductor 21 is irradiated with the laser beam, the charge of the portion irradiated with the laser beam disappears and the surface of the photoconductor 21 is on the photoconductor 21. An electrostatic latent image corresponding to the image data (each color of YMCK) included in the original image information is formed.

When the electrostatic latent image formed on the photoconductor 21 reaches the developing device 24, a developing bias is applied to the developing roll 240 in the developing device 24 by a developing bias power supply (not shown). Then, the powder particles of each color held on the peripheral surface of the developing roll 240 adhere to the electrostatic latent image of the photoconductor 21, respectively, and the powder particles corresponding to the image data of each color of the original image information are attached to the photoconductor 21. An image is formed.

Further, the intermediate transfer belt 32 is conveyed to the gap formed by the primary transfer device 30 of each color and the photoconductor 21, so that the intermediate transfer belt 32 is pressed against the photoconductor 21 of each color. At this time, when the primary transfer bias is applied by the primary transfer device 30 of each color, the powder particle image of the image data of each color formed on the photoconductor 21 is transferred to the intermediate transfer belt 32. Therefore, by controlling the movement of the intermediate transfer belt 32 so that the transfer start positions of the powder particle images of each color to the intermediate transfer belt 32 are matched, the powder particle images of each color are superimposed and correspond to the original image information. The resulting powder particle image is formed on the intermediate transfer belt 32.

In the photoconductor 21 on which the powder particle image is transferred to the intermediate transfer belt 32, deposits such as residual particles adhering to the surface of the photoconductor 21 are removed by the cleaning device 25, and the residual charge is removed.

The powder particle image corresponding to the original image information formed on the intermediate transfer belt 32 reaches the secondary transfer device 40 as the intermediate transfer belt 32 rotates. On the other hand, the recording medium MD having the conductive layer Ep formed by the conductive layer forming portion 16 and stabilized by the conductive layer stabilizing portion 18 is carried into the image forming portion 12. The recording medium MD is conveyed to the gap between the backup roll 42 of the secondary transfer device 40 and the secondary transfer roll 44 via the transfer belt 54B by driving the transfer unit 54.

In the secondary transfer device 40, the voltage of the negative electrode is applied from the secondary transfer power supply 46 to the roll pair at the timing when the recording medium MD is conveyed to the gap formed by the roll pair of the backup roll 42 and the secondary transfer roll 44. Will be done. Then, in addition to the pressing force that presses the recording medium MD and the intermediate transfer belt 32 while the roll pair rotates, the charged powder particle image is peeled from the intermediate transfer belt 32 by the electric field generated in the gap between the roll pairs. A force is generated, and the powder particle image formed on the intermediate transfer belt 32 is transferred to the recording medium MD.

When the powder particle image is transferred by the secondary transfer device 40, the power is supplied from the feeding unit 48 to the conductive layer Ep formed on the recording medium MD. As a result, an electric field can be generated between the backup roll 42 and the conductive layer Ep of the recording medium MD regardless of the thickness and the insulating property of the recording medium MD, and the charged powder particle image is intermediately transferred. A force for peeling from the belt 32 is generated, and the powder particle image formed on the intermediate transfer belt 32 can be transferred to the recording medium MD.

The recording medium MD on which the powder particle image is transferred is carried out toward the heat fixing unit 14 by the drive of the transport unit 54. The powder particle image transferred onto the recording medium MD is heated and melted by the heat source 14-1 of the heat fixing unit 14, and fixed on the recording medium MD.

Further, in the intermediate transfer belt 32 in which the powder particle image is transferred to the recording medium MD, the deposits such as residual toner adhering to the surface of the intermediate transfer belt 32 are removed by the belt cleaner 52.

Further, the transport belt 54B on which the powder particle image is transferred to the recording medium MD is removed from the deposits such as residual toner adhering to the surface by the cleaning device 56, and the residual charge is removed.

As described above, regardless of the thickness and the insulating property of the recording medium MD, an image corresponding to the original image information is formed on the recording medium MD, and the image forming operation is completed. That is, the powder particle image formed on the intermediate transfer belt 32 is transferred to the recording medium MD and fixed to form an image on the recording medium MD.

FIG. 11 shows an example of the relationship between the powder particle layers of each color in the intermediate transfer belt 32 and the recording medium MD. In FIG. 11, in the image forming apparatus 10, the electrostatic latent image of each color is developed to form a layer of powder particle images of each color on the intermediate transfer belt 32, and then transferred to the recording medium MD, for example, a recording material. A state in which a color image (multicolor image) is formed on the MD is shown.

As shown in FIG. 11, when a color image (multicolor image) is formed and then transferred in the image forming apparatus 10, the intermediate transfer belt 32 has a powder particle image of each color in which the latent image of each color is developed, that is, Layers (powder particle layers) of powder particles of each color of Y, M, C, and K are sequentially laminated. The powder particle image formed by the plurality of powder particle layers laminated on the intermediate transfer belt 32 is fixed after being transferred to the recording medium MD. In this way, when the powder particle image by the plurality of powder particle layers is transferred to the recording medium MD, the recording medium MD keeps the state in which the powder particle layers of different colors are laminated on the intermediate transfer belt 32. Transfer to.

<Powder particles>
Next, the powder particles used in the heat-curable powder coating material suitable for the high-dielectric-constant particles and the low-dielectric-constant particles used in the image forming apparatus 10 according to the present embodiment will be described. However, it will be referred to as powder particles according to the present embodiment.

The powder particles according to this embodiment include a thermosetting resin and a thermosetting agent. As the powder particles, particles having a so-called core / shell structure may be used.

The powder particles according to the present embodiment may be either a transparent powder coating material (clear coating material) containing no coloring agent in the powder particles or a colored powder coating material containing a coloring agent in the powder particles. .. Further, as the powder particles, those having a volume particle size distribution index GSDv of 1.50 or less and an average circularity of 0.96 or more of the powder particles can be used in order to reduce the diameter. ..

(Thermosetting resin)
The thermosetting resin is a resin having a thermosetting reactive group. Examples of the thermosetting resin include various types of resins conventionally used for powder particles.
The thermosetting resin is preferably a water-insoluble (hydrophobic) resin. When a water-insoluble (hydrophobic) resin is applied as the thermosetting resin, the environmental dependence of the charging characteristics of the powder particles is reduced. Further, when the powder particles are produced by the aggregation and coalescence method, the thermosetting resin is preferably a water-insoluble (hydrophobic) resin from the viewpoint of realizing emulsification and dispersion in an aqueous medium. The water-insoluble (hydrophobic) means that the amount of the target substance dissolved in 100 parts by mass of water at 25 ° C. is less than 5 parts by mass.

Among the thermosetting resins, at least one selected from the group consisting of thermosetting (meth) acrylic resins and thermosetting polyester resins is preferable.

(Thermosetting agent)
The thermosetting agent is selected according to the type of curing reactive group of the thermosetting resin.
Specifically, when the curing reactive group of the thermosetting resin is an epoxy group, the thermosetting agent includes, for example, succinic acid, glutaric acid, adipic acid, pimeric acid, suberic acid, azelaic acid, sebatic acid, and dodecane. Diacid, Aicosandioic acid, Maleic acid, Citraconic acid, Itaconic acid, Glutaconic acid, Phthalic acid, Trimellitic acid, Pyromellitic acid, Tetrahydrophthalic acid, Hexahydrophthalic acid, Cyclohexene-1,2-dicarboxylic acid, Trimerit Acids such as acids and pyromellitic acids; anhydrides of these acids; urethane modified products of these acids and the like can be mentioned. Among these, as the thermosetting agent, an aliphatic dibasic acid is preferable from the viewpoint of the physical properties of the coating film and storage stability, and dodecane diic acid is particularly preferable from the viewpoint of the physical properties of the coating film.

When the curing reactive group of the thermosetting resin is a carboxyl group, the thermosetting agent includes, for example, various epoxy resins (for example, polyglycidyl ether of bisphenol A), epoxy group-containing acrylic resin (for example, glycidyl group-containing acrylic resin). Etc.), polyglycidyl ethers of various polyhydric alcohols (eg 1,6-hexanediol, trimethylolpropane, trimethylolethane, etc.), polyglycidyl esters of various polyvalent carboxylic acids (eg phthalic acid, terephthalic acid, isophthales, etc.) Acids, hexahydrophthalic acid, methylhexahydrophthalic acid, trimellitic acid, pyromellitic acid, etc.), various alicyclic epoxy group-containing compounds (eg, bis (3,4-epoxycyclohexyl) methyladipate, etc.), hydroxyamide (For example, triglycidyl isocyanurate, β-hydroxyalkylamide, etc.) and the like.

When the curing reactive group of the thermosetting resin is a hydroxyl group, examples of the thermosetting agent include polyblock isocyanate and aminoplast. Examples of the polyblock polyisocyanate include various aliphatic diisocyanates (for example, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, etc.), various cyclic aliphatic diisocyanates (for example, xylylene diisocyanate, isophorone diisocyanate, etc.), and various aromatic diisocyanates (for example, xylylene diisocyanate, isophorone diisocyanate, etc.). Organic diisocyanates such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, etc.; adjuncts of these organic diisocyanates to polyhydric alcohols, low molecular weight polyester resins (eg polyester polyols), water, etc .; Polymers (polymers also containing isocyanurate-type polyisocyanate compounds); various polyisocyanate compounds such as isocyanate biuret compounds blocked with a known and commonly used blocking agent; self-blocking having a uretdione bond as a structural unit Examples include polyisocyanate compounds.

The thermosetting agent may be used alone or in combination of two or more.

The content of the thermosetting agent is preferably 1% by mass or more and 30% by mass or less, and preferably 3% by mass or more and 20% by mass or less, based on the thermosetting resin.
When a thermosetting resin is applied as the resin of the resin coating portion, the content of the thermosetting agent means the content of the core portion and the resin coating portion with respect to the total thermosetting resin.

-Colorant-
The powder particles may contain a colorant.
Examples of the colorant include pigments. As the colorant, a dye may be used in combination with the pigment.
Pigments include, for example, inorganic pigments such as iron oxide (for example, red iron oxide), titanium oxide, titanium yellow, zinc white, lead white, zinc sulfide, lithopone, antimony oxide, cobalt blue, carbon black; quinacridone red, phthalocyanine blue, etc. Examples thereof include organic pigments such as phthalocyanine green, permanent red, Hansa yellow, indanthrone blue, brilliant first scarlet, and benzimidazolone yellow.
Other examples of pigments include bright pigments. Examples of the brilliant pigment include metal powders such as pearl pigments, aluminum powders, and stainless steel powders; metal flakes; glass beads; glass flakes; mica; phosphorescent iron oxide (MIO) and the like.

The colorant may be used alone or in combination of two or more.

The content of the colorant is selected according to the type of pigment and the color, lightness, depth and the like required for the coating film. For example, the content of the colorant is preferably 1% by mass or more and 70% by mass or less, and preferably 2% by mass or more and 60% by mass or less, based on the total resin of the core portion and the resin coating portion.

-Other additives-
The powder particles may contain other additives.
Examples of other additives include various additives used in powder coating materials. Specifically, other additives include, for example, surface conditioners (silicone oils, acrylic oligomers, etc.), foaming (armpit) inhibitors (eg, benzoins, benzoin derivatives, etc.), and curing accelerators (amine compounds, imidazole compounds, etc.). , Cationic polymerization catalyst, etc.), plasticizers, charge control agents, antioxidants, pigment dispersants, flame retardants, fluidizers, and the like.

Next, the image forming control unit 50 that performs the image forming operation by the image forming apparatus 10 will be described.
FIG. 12 shows an example of the configuration of the image forming control unit 50 that performs the image forming operation by the image forming apparatus 10.
FIG. 12 shows an example of a computer 50X in which the image formation control unit 50 is composed of a computer. The computer 50X has a configuration in which a CPU (Central Processing Unit) 50A, a ROM (Read Only Memory) 50B, a RAM (Random Access Memory) 50C, and an input / output interface (I / O) 50E are connected via a bus 50F. Yes, a non-volatile memory 50D is also connected to the I / O 50E. Further, an image forming mechanism unit 60, an operation display unit 62, and a communication unit 64 are connected to the I / O 50E.

The image formation control program 50P to be executed by the computer 50X is stored in the ROM 50B. The CPU 50A expands the image formation control program 50P from the ROM 50B into the reading RAM 50C, and executes processing by the image formation control program 50P. When the CPU 50A executes the process by the image formation control program 50P, the computer 50X operates as the image formation control unit 50. The image formation control program 50P may be provided by a recording medium such as a CD-ROM.

Further, in the non-volatile memory 50D, various types of information indicating the potential required for the image forming apparatus 10 to execute the image forming operation and various types for obtaining the potential at the portion where the electrostatic latent image of the photoconductor 21 is formed are obtained. Information indicating the voltage of is stored.

The image forming mechanism unit 60 is a device necessary for the image forming apparatus 10 to perform an image forming operation, for example, a photoconductor 21, a charger 22, an exposure unit 23, a developing device 24, an intermediate transfer belt 32, and a secondary. Each drive unit of the transfer device 40 is included. The image forming mechanism portion 60 may include each driving portion of the conductive layer forming portion 16, the conductive layer stabilizing portion 18, and the heat fixing portion 14, and the conductive layer forming portion 16 and the conductive layer may be included. A control signal may be output to each of the stabilizing unit 18 and the heating fixing unit 14 via the communication unit 64 to operate each of them.

The operation display unit 62 includes a display button for receiving operation instructions, a touch panel type display (not shown) for displaying various information, and hardware keys (not shown) such as a numeric keypad and a start button. ..

The communication unit 64 is an interface for mutual data communication with a terminal device such as a personal computer (not shown).

Next, the image forming process executed by the computer 50X operating as the image forming control unit 50 will be described. In the present embodiment, each of the conductive layer forming portion 16, the conductive layer stabilizing portion 18, and the heat fixing portion 14 has an independent configuration, and a control signal is output to each of them via the communication unit 64. The case of operating will be described.

FIG. 13 shows the processing flow of the image formation control program 50P executed by the CPU 50A of the computer 50X.

The image formation control program 50P is executed by the CPU 50A when the power is turned on to the image forming apparatus 10 and an image formation start instruction is received from the CPU 50A.

First, in step S90, a control signal is output to the conductive layer forming unit 16 via the communication unit 64 to operate the conductive layer forming unit 16. That is, in step S90, a control signal indicating that the conductive layer Ep is formed on the recording medium MD is output to the conductive layer forming unit 16 via the communication unit 64. In the conductive layer forming unit 16, the conductive material coating unit 16-1 executes a process of forming the conductive layer Ep on the recording medium MD. The conductive layer forming unit 16 returns a signal indicating the completion of forming the conductive layer in response to the completion of the forming process of the conductive layer Ep on the recording medium MD. Then, when the CPU 50A receives the signal indicating that the formation of the conductive layer is completed, the CPU 50A outputs a control signal indicating that the conductive layer Ep is stabilized to the recording medium MD to the conductive layer stabilizing unit 18 via the communication unit 64. The conductive layer stabilizing unit 18 stabilizes the conductive layer Ep by, for example, drying in the mold release unit 18-1 while transporting the recording medium MD by the transport unit 19. Then, the conductive layer stabilizing portion 18 is cooled by the cooling unit 18-3 and then conveyed to the image forming portion 12 in order to lower the temperature raised by, for example, drying for stabilization, and the stabilization process of the conductive layer Ep is completed. Returns a signal indicating. Then, when the CPU 50A receives the signal indicating the end of the conductive layer stabilization process, the process shifts to step S100.

Next, in step S100, the original image information indicating the color image formed on the recording medium MD is acquired from a terminal device (not shown) via the communication unit 64. Next, in step S102, an electrostatic latent image is formed using the original image information acquired in step S100. That is, a charging bias is applied to the charger 22, the surface of the photoconductor 21 is charged to the negative electrode, a modulation signal of each color of YMCK based on the original image information is output, and the exposure unit 23 of the corresponding developing unit 20 outputs the modulation signal. The laser beam corresponding to the modulated signal is output. The laser beam is applied to the surface of the photoconductor 21, the electric charge of the irradiated portion of the laser beam is extinguished, and an electrostatic latent image is formed.

In the next step S104, the electrostatic latent image formed in step S102 is developed. That is, in the developing device 24 of each color, the powder particles colored in the corresponding colors and charged in the negative electrode are attached to the portion where the electrostatic latent image is formed on the surface of the photoconductor 21. Specifically, a development bias is applied to the development roll 240 in the developing device 24, and powder particles of each color held on the peripheral surface of the development roll 240 are attached to the electrostatic latent image of the photoconductor 21. Therefore, when the electrostatic latent image formed on the photoconductor 21 reaches the developing device 24, a powder particle image corresponding to the electrostatic latent image is formed.

In the next step S106, the powder particle image developed in step S104 is transferred. That is, first, a primary transfer bias is applied to the primary transfer device 30 of each color, and the powder particle image of each color formed on the photoconductor 21 is transferred to the intermediate transfer belt 32. Next, a secondary transfer voltage (or current) is applied to the secondary transfer device 40 and the feeding unit 48 to transfer the powder particle image formed on the intermediate transfer belt 32 to the recording medium MD.

In the next step S108, the powder particle image transferred onto the recording medium MD is heated and melted by the heat fixing unit 14, fixed to the recording medium MD, and the image forming process is completed.

As described above, according to the present embodiment, the conductive layer Ep is formed in advance on the recording medium MD, and then the charged powder particles are transferred. Thereby, regardless of the thickness and the insulating property of the recording medium MD, multiple transfer by the powder particles can be easily performed, and the thickness of the recording medium MD increases as the thickness of the recording medium MD increases and the insulating property becomes higher. It is possible to suppress an increase in the transfer voltage that increases accordingly. Therefore, the transfer voltage can be determined according to the thickness and the insulating property of the recording medium MD, and the transfer electric field generated can be reduced as compared with the case where the powder particle image is transferred. In addition, it is possible to suppress transfer defects due to insufficient transfer voltage to be generated.

In the present embodiment, as compared with the case where high dielectric constant particles and low dielectric constant particles are alternately transferred and layers of each powder particle are laminated to form a layer in which insulating powder particles are laminated. Therefore, the thickness of the laminated layers can be increased. Further, by making the colors of the high dielectric constant particles and the low dielectric constant particles different from each other, it is possible to obtain a vivid color image.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. Various changes or improvements can be made to the above embodiments without departing from the gist of the invention, and the modified or improved forms are also included in the technical scope of the present invention.

10 Image forming device 12 Image forming part 14 Heat fixing part 16 Conductive layer forming part 18 Conductive layer stabilizing part 20 Development unit 21 Photoreceptor 22 Charger 23 Exposure part 24 Developer 30 Primary transfer device 32 Intermediate transfer belt 40 Secondary transfer device 42 Backup roll 44 Secondary transfer roll 48 Feeding unit 50 Image formation control unit 50X Computer Ep Conductive layer MD Recording medium

Claims (12)

A conductive layer forming portion that supplies a conductive material to form a conductive layer on an image forming object that requires a larger electric field as the thickness increases when charged particles are attached.
An image forming unit that forms an image by transferring a charged particle image formed of charged particles to the conductive layer of the image forming object.
A bonding portion for attaching a charged particle image formed of the charged particles to the conductive layer by applying a voltage having a polarity opposite to that of the charged particle image to the conductive layer.
An image forming apparatus having a,
The conductive layer forming portion is provided with the conductive layer on the main surface of the plate-shaped member including the image-forming surface that forms the image on the image-forming object of the plate-shaped member, and is provided on the main surface of the plate-shaped member. An image forming apparatus that provides the conductive layer on a surface other than the main surface of the continuous plate-shaped member . Includes a first transport unit that transports the image-forming object.
The image forming apparatus according to claim 1, further comprising a particle cleaning unit for cleaning the particles remaining in the first transport unit on the downstream side in the transport direction of the first transport unit after forming the charged particle image. A conductive layer forming portion that supplies a conductive material to form a conductive layer on an image forming object that requires a larger electric field as the thickness increases when charged particles are attached.
An image forming unit that forms an image by transferring a charged particle image formed of charged particles to the conductive layer of the image forming object.
A bonding portion for attaching a charged particle image formed of the charged particles to the conductive layer by applying a voltage having a polarity opposite to that of the charged particle image to the conductive layer.
It is an image forming apparatus equipped with
Includes a first transport unit that transports the image-forming object.
A particle cleaning unit for cleaning the particles remaining in the first transport unit is provided on the downstream side in the transport direction of the first transport unit after the formation of the charged particle image .
The first transport unit includes a transport belt, and the transport belt is an image forming apparatus including a fixing portion for fixing the image forming object on the transport belt during transport. The conductive layer forming portion is provided with the conductive layer on the main surface of the plate-shaped member including the image-forming surface that forms the image on the image-forming object of the plate-shaped member, and is provided on the main surface of the plate-shaped member. The image forming apparatus according to claim 3, wherein the conductive layer is provided on a surface other than the main surface of the continuous plate-shaped member. The transport belt has a plurality of perforations, and the fixing portion fixes the image-forming object through the plurality of perforations by a suction device.
The image forming apparatus according to claim 3 or 4. The image according to any one of claims 1 to 5, which includes a demolding portion that demolds the conductive layer formed by the conductive layer forming portion so as to have a predetermined releasability. Forming device. The conductive layer forming portion includes a second conveying portion that conveys an image-forming object before forming the conductive layer.
The image forming apparatus according to claim 6, wherein the image forming portion and the conductive layer forming portion are provided at positions separated by a predetermined distance. The image forming apparatus according to claim 7, further comprising a conductive material cleaning unit for cleaning the conductive material remaining in the second transport unit on the downstream side in the transport direction of the second transport unit. Any one of claims 1 to 8, wherein the particles include powder particles having thermocurability and include a heat-fixing portion for heat-fixing the charged particle image adhered to the conductive layer at the image forming portion. The image forming apparatus according to the section. A conductive layer forming portion that supplies a conductive material to form a conductive layer on an image forming object that requires a larger electric field as the thickness increases when charged particles are attached.
An image forming unit that forms an image by transferring a charged particle image formed of charged particles to the conductive layer of the image forming object.
A bonding portion for attaching a charged particle image formed of the charged particles to the conductive layer by applying a voltage having a polarity opposite to that of the charged particle image to the conductive layer.
It is an image forming apparatus equipped with
The conductive layer formed by the conductive layer forming portion includes a demolding portion that demolds the conductive layer so as to have a predetermined releasability.
The conductive layer forming portion includes a second conveying portion that conveys an image-forming object before forming the conductive layer.
The image forming portion and the conductive layer forming portion are provided at positions separated by a predetermined distance.
A conductive material cleaning unit for cleaning the conductive material remaining in the second transport unit is included on the downstream side in the transport direction of the second transport unit.
Image forming device. The particles include powder particles having heat curability, and include a heat-fixing portion for heat-fixing the charged particle image adhered to the conductive layer at the image forming portion.
The image forming apparatus according to claim 10. A conductive material is supplied to an image-forming object that requires a larger electric field as the thickness increases when particles are attached to form a conductive layer.
An image of charged particles formed of charged particles is transferred to the conductive layer of the image-forming object to form an image.
An image forming method in which a voltage having a polarity opposite to that of the charged particle image is applied to the conductive layer to attach a charged particle image formed of the charged particles to the conductive layer.
When the conductive layer is formed, the conductive layer is provided on the main surface of the plate-shaped member including the image-forming surface that forms the image on the image-forming object of the plate-shaped member, and the main surface of the plate-shaped member is provided. An image forming method in which the conductive layer is provided on a surface other than the main surface of the plate-shaped member that is continuous with the plate-shaped member .

Images