JP2000118021A - Image-forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image-recording apparatus with which a pixel position by coloring material particles is autonomously controlled highly accurately, no image quality deterioration occurs and image defects by a feed failure of coloring material particles are not brought about. SOLUTION: The image-forming apparatus has an image carrier 2, an image signal input means 3, a coloring material particle feed means 4 and a transfer means 10. The image carrier 2 to a surface of which an image by coloring material particles 1 is formed has a coloring material particle adhesion region of a smaller area than a unit pixel region within the unit pixel region. The coloring material particle feed means 4 supplies the coloring material particles 1 by a coloring material particle-holding supplying roll 4h which rotates in a driven direction to the image carrier 2 while holding the coloring material particles 1 at a surface and supplies the coloring material particles 1 to the surface of the image carrier 2, and a pressure-applying member 4j for applying a pressure to the coloring material particle-holding supplying roll 4h holding a layer of the coloring material particles 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a white / black, color image forming apparatus which can be used in a copying machine, a facsimile, a printer, and the like.

[0002]

2. Description of the Related Art In an image forming process of a conventional electrophotographic technique, several factors overlap and "pixel position shift" occurs. The term “pixel position shift” as used herein refers to a position shift of one toner particle, that is, scattering and spilling of toner, a microscopic method of movement and transfer that does not faithfully follow a latent image electric field, and a color shift. And a systematic macro perception relating to the entire copying machine and printer device.

First, the charge q held by the toner, the electrostatic force caused by the electric field E applied between the photoreceptor and the developing electrode, the paper or the intermediate transfer member, and the toner applied to the target medium by F = q · E The problem in the transfer of the image will be described.
The spatial electric field generated between the regular rectangular latent image on the photoreceptor and the developing electrode is shown, for example, in FIG. 25 (Journal of the Electrophotographic Society of Japan No. 104, Vol. 32 No. 3, 1993). The lines of electric force are such that the actual photoconductor and developing electrode are not perfectly parallel electrodes, and the lines of electric force are deflected with a curvature due to the edge effect at the edge of the rectangular latent image. It is not completely parallel to the plane. FIG. 25 shows the profile of the contrast potential when shifted from the center of the latent image by X in the process direction (photoconductor rotation direction) and by Y in the target electrode direction (gap). Here, a length of 100 μm
Latent images having a uniform charge density of m width are set at intervals of 100 μm.

FIG. 26 shows a contrast potential distribution when scanning is performed in the Y direction. The solid line a in the figure is
The position at the center of the central latent image, the dotted line b is the result of scanning at a position intermediate between the central latent image and the adjacent latent image, and the dashed line c is the result of scanning at a point 70 μm further away from the outer end of the outermost latent image.
These calculation results show that the maximum point of the contrast potential becomes lower as the distance from the center of the latent image increases in the process direction, and that the point shifts between the photosensitive member and the target electrode. In the actual development process, development does not start at the central portion of the latent image (X = 0) shown in FIG. 25, but is determined by the effective electric field threshold in the development nip (electric field of the photoconductor, toner charge, and development electrode bias). At the point in time when the effective electric field threshold value is reached, the actual development starts, and therefore, it is equal to the development that the X is shifted as shown in FIG.

[0005] Although the toner receives an electrostatic force for transferring and moving, the toner has a low contrast potential and is shifted in position, so that it cannot be reliably brought to the original pixel position. This is a fundamental problem of electrophotography in electrodynamics.

[0006] On the other hand, as a macro method, color shift,
There is a problem of color registration. This is the accuracy of the rotation or movement of the photoconductor, the transfer drum and the paper transport belt usually used in copiers and printers (hereinafter referred to as
It largely depends on “motion quality”, and occurs as a color shift in a low frequency band, and as a stripe in a regular process direction (hereinafter, referred to as “banding”) in a high frequency band. The color shift and banding caused by this poor motion quality appear as image defects in high-definition halftone reproduction or color character reproduction,
Significantly degrades image quality.

For this reason, in conventional copiers and printers, in order to improve the motion quality of the photosensitive member and the conveyor belt, control such as feed forward and feedback is performed, or the mechanical accuracy of components and assembly is improved. Has been responding. In addition, a change in light amount of the recording information writing device due to a change over time or an environmental change, particularly a change in temperature, a shift in synchronicity in each mechanical configuration (for example, a roll diameter for driving a transport belt in a tandem type copier or a printer) Is adjusted so that the ratio between the distance and the photosensitive member distance becomes an integer, but it is necessary to cope with various problems such as the deviation due to the temperature expansion of the apparatus frame and the roll. This poses problems such as an increase in the size, complexity, and cost of the apparatus, and can be considered to be the limit of the conventional electrophotographic technique as a recording technique that does not reduce the reliability.

[0008] Pixel position deviation in the printing technology field has an aspect of achieving higher accuracy in exchange for higher price of the apparatus. Basically, there is no misalignment of pixels in the image writing process such as electrophotography due to having a plate.Color printing of yellow, magenta, cyan, and black is unique to printing ink from plate cylinder to blanket cylinder and paper. The physical phenomenon of `` thixotropic properties '' means that printing is performed stably, and the plate cylinder, blanket cylinder, and paper support / transport cylinder have high reliability and durability while being driven by high precision helical gears etc. That
By performing pixel position deviation adjustment by a specialized operator, the pixel position deviation of high-quality printing is 15 to 3 as an average value.
0 μm is obtained. However, there remains a problem that an increase in the size and price of the entire apparatus is inevitable, and that the on-demand property is not sufficiently supported as a recording technique aimed at business and office use.

Recording technology Oce'3125C Euro Color Copi announced at CeBIT '96
This recording technique is a recording technique for visualizing toner by bias development without using an electrostatic latent image formed by a photoreceptor. FIG. 27 shows a cross section of the imaging drum. The ring-shaped ring electrode 70 is the insulating layer 7
1 is disposed at a resolution of 400 dpi in the axial direction, and the surface is covered with a dielectric layer 69.

FIG. 28 is a block diagram of the entire apparatus. Here, the suffixes K, B, R, G, M, C, and Y of the respective numbers represent the respective colors, and the suffixes are omitted when representing them. A fixed electrode group arranged in a matrix for transmitting recording information from a slip ring (not shown) is provided in the imaging drum 72, and the toner from the developing roll 74 to which an electric field is applied in accordance with the recording information is applied. It moves onto the imaging drum 72 to form an image. Imaging drums 72 are arranged around the intermediate transfer drum 73 in tandem from black 72K to yellow 72Y,
The developing roll 74 is also changed from black 74K to yellow 74.
Up to Y are arranged on each imaging drum. The recording process starts with black development and starts with black, and each of the seven colors is formed on the imaging drum 72 in a single-layer configuration. Then, the toner of each color is transferred onto the intermediate transfer drum 73 without overlapping. The paper is stored in the paper cassette 5 so that the timing matches the leading edge of the image.
8 to be transported. The image on the intermediate transfer drum 73 is transferred to the sheet by the secondary transfer roll 75 and the output tray 6
It is discharged to 2.

This technology is 63.5 μm (400 dpi).
The pixel position for each toner within that pixel is not controlled. In addition, since the toner is a conductive magnetic one-component toner and has a single toner layer, that is, a recording process of forming a color image structure of a juxtaposition type, a pixel position shift between pixels (color registration). Has a great effect on image quality degradation, especially on the color space reproduction area (color gamut).

As another recording technique, there is a toner jet recording technique represented by Array Printers AB. This is a system in which a non-magnetic one-component color toner (black is a magnetic one-component toner) on a developing sleeve flies directly onto paper to form a color image. A two-dimensionally arranged mesh-shaped control electrode is provided between the developing sleeve and the paper, and a uniform back electrode is provided on the back of the paper.
With the voltage of 0 V and the control electrode voltage (275 W during printing / -50 V during non-printing), the toner is caused to fly on the paper according to the recording information. The problem with this technology is that
The pore diameter of the mesh is about 100 to 150 μm, and the toner flies as a lump, causing rebound on the paper, resulting in a high background (the occurrence of paper background contamination). This is, of course, a weakness not only in the rebound phenomenon but also in the recording process itself in which the toner is caused to fly in an aggregate, and is the greatest factor that deteriorates the graininess.

Another problem is that the toner is clogged and adhered to the control electrode. A cleaning device for the control electrode is required, which leads to an increase in size and cost of the device. On the other hand, in the technique disclosed in Japanese Patent Application Laid-Open No. 4-83658, an AC voltage is applied to the back surface of the aperture electrode to prevent back surface contamination due to toner adhesion. In any case, the control electrode is inserted between the developing sleeve and the back electrode having a very small gap of about 200 μm, and the problem of electrode contamination in the recording technique of passing the toner through the hole of the control electrode is avoided. This is a technical issue that cannot be passed.

As means for solving the above problems, there is a technique described in Japanese Patent Application No. 9-308678 filed by the present inventors (hereinafter referred to as "A technique"). In the A technique, in each pixel area when the surface of the image carrier is divided into a large number of pixel areas, an adhesive force changing section that is narrower than each pixel area and whose adhesive force with a coloring material changes by a predetermined stimulus is provided. By using the image carrier having the color material particles, the color material particles can be arranged without being shifted from a desired pixel position on the recording medium.
When the color material particles are transferred to a position shifted from a desired pixel position on the recording medium, the particles are scattered, the granularity is deteriorated due to the spill, the color space reproduction area (color gamut) is narrowed, and the color is reduced. Degradation of image quality such as generation of registration and banding occurs. However, the technology A can completely solve these problems.

[0015]

The technique A makes it possible to obtain the best image without any pixel displacement, but on the other hand, the technique of supplying the color material particles is more important than the conventional technique. If this is not enough, you will not be able to benefit from the excellent technology. The reason is shown in FIG.
This will be described with reference to FIG.

FIG. 29 is a sectional view (view from the side) and a plan view (view from the top) of the surface of the image carrier drum in the prior art and the A technique. It is drawn by paying attention to the relationship between the region having an adhesive force to the color material) and the pixel width. Compared with the prior art, the technology A has a smaller probability that the color material particles contact the adhesive force region because the adhesive region is smaller than the unit pixel region and smaller than the color material particles. When using a short-range force such as van der Waals force or liquid bridging force without using a long-range force such as an electrostatic force or a magnetic force as the adhesion force, apply an external force to the particles and move the particles to the adhesion region. Need to be brought into contact.
Further, in the A technology, only one color material particle is arranged in one pixel. Therefore, there is a pixel in which the color material particles are not arranged due to a supply failure, such as a region surrounded by a broken line in the A technology plan view in FIG. If it does, image defects will result. Therefore, as described above, the technique of supplying the color material particles is an important technique in the technique A.

In the technique A, as shown in FIG. 30A, as a means for supplying the color material particles 1, a color material particle supply roll 4a having the color material particles 1 arranged on the entire surface is rubbed against the image carrier 2. Was supplied. However, when the layer thickness of the color material particles 1 previously arranged on the color material particle supply roll 4a is not uniform, the color material particles 1 cannot be uniformly supplied to the image carrier 2, There is a possibility that an image defect will occur as in the area surrounded by the broken line. Also, as shown in FIG. 30B, the layer of the color material particles 1 formed by the color material particle supply rolls 4b in which the adhesion portions with the color material particles 1 are discretely arranged has a slightly improved uniformity in layer thickness. Insufficient filling of the color material particles 1 on the surface of the color material particle supply roll 4b or the image carrier 2 and the color material particle supply roll 4
b, it may not be possible to uniformly supply the colorant particles 1 to the image carrier 2 due to a speed difference between
Resolving image defects is not yet complete.

A cascade developing system exists as a developing means used in the early days of electrophotographic technology. This is US
P2618552 and the like, and a method of gravity-filling color material particles into a latent image portion like a waterfall. this is,
When the color material particles roll on the image, they adhere to the image portion due to the electrostatic force of the image. However, since the gravity acting on the color material particles and the adhesive force between the color material particles are almost the same, the gaps in the color material particle layer inevitably increase. As a result, color material particles that cannot be brought into contact with the image area are generated, resulting in image omission.On the other hand, the use of an electrostatic latent image causes an edge effect, which is not suitable for reproducing an area image or halftone. Have.

Accordingly, it is an object of the present invention to provide an image recording apparatus which can make the technique A which can solve the above-mentioned conventional problems even more effective. That is, in the present invention, the pixel position of the color material particles is autonomously controlled with high accuracy,
It is an object of the present invention to provide an image recording apparatus that does not cause deterioration in image quality and does not cause image defects due to a supply failure of color material particles.

[0020]

The above object is achieved by the present invention described below. That is, the present invention provides: (1) an image carrier having an image formed of color material particles formed on a surface thereof, wherein each surface of the image carrier is divided into a number of pixel regions, and each unit pixel region has: An adhesive force changing portion having an area smaller than the unit pixel region, comprising a viscoelastic substance whose adhesive force with the color material particles changes by an external stimulus, and capable of attaching the color material particles to the center thereof. An image carrier having an image signal input means for forming an image on the surface of the image carrier by the distribution of adhesion to color material particles by inputting an external stimulus according to an image signal to the image carrier. A color material particle supply means for supplying color material particles to the surface of the image carrier; and an image formed by the color material particles formed on the surface of the image carrier, directly or with a predetermined intermediate transfer medium interposed therebetween. Transfer to transfer the image to the image recording medium where the image is finally recorded Means for supplying color material particles to the surface of the image carrier while holding the color material particles on the surface and rotating in the driven direction with the image carrier. An image forming apparatus, characterized in that it is means for supplying color material particles by a holding supply roll and a pressure applying member that applies pressure to the color material particle holding supply roll holding a layer of color material particles. is there.

(2) An image carrier on which an image of color material particles is formed on the surface, wherein the unit is located in each unit pixel area when the surface of the image carrier is divided into a number of pixel areas. It has a smaller area than the pixel area, and comprises a viscoelastic substance whose adhesive force with the color material particles changes due to external stimuli,
And, an image carrier having an adhesive force changing portion capable of adhering the color material particles to the center thereof, and by inputting an external stimulus according to an image signal to the image carrier, on the surface of the image carrier, Image signal input means for forming an image based on the distribution of adhesion to color material particles, color material particle supply means for supplying color material particles to the surface of the image carrier, and color material formed on the surface of the image carrier Transfer means for transferring an image of particles directly or via a predetermined intermediate transfer medium to an image recording medium on which the image is finally recorded, A color material particle holding supply roll for holding the color material particles on the surface and supplying the color material particles to the surface of the image carrier while rotating in the driven direction with the image carrier, and the color in which a layer of the color material particles is held A pressure applying member for applying pressure to the material particle holding and supplying roll; An image forming apparatus which is a means for supplying Riirozai particles.

(3) An image carrier on which an image of color material particles is formed on the surface, wherein the unit is located in each unit pixel area when the surface of the image carrier is divided into a number of pixel areas. It has a smaller area than the pixel area, and comprises a viscoelastic substance whose adhesive force with the color material particles changes due to external stimuli,
And, an image carrier having an adhesive force changing portion capable of adhering the color material particles to the center thereof, and by inputting an external stimulus according to an image signal to the image carrier, on the surface of the image carrier, Image signal input means for forming an image based on the distribution of adhesion to color material particles, color material particle supply means for supplying color material particles to the surface of the image carrier, and color material formed on the surface of the image carrier Transfer means for transferring an image of particles directly or via a predetermined intermediate transfer medium to an image recording medium on which the image is finally recorded, A color material particle holding supply roll for holding the color material particles on the surface and supplying the color material particles to the surface of the image carrier while rotating in the driven direction with the image carrier, and the color in which a layer of the color material particles is held A pressure applying member for applying pressure to the material particle holding and supplying roll; An image forming apparatus which is a means for supplying Riirozai particles.

(4) The method according to any one of (1) to (3), wherein the process speed of the color material particle holding and supplying roll is set higher than the process speed of the image carrier.
2. The image forming apparatus according to 1. (5) The pressure applied to the color material particle holding / supply roll by the pressure applying member is set to be smaller than the pressure applied to the image carrier by the color material particle holding / supply roll. An image forming apparatus according to any one of (1) to (4).

[0024]

Embodiments of the present invention will be described below. FIG. 1 is a configuration diagram of an image forming apparatus according to a first embodiment of the present invention. The image forming apparatus shown in FIG.
A drum-shaped image carrier 2 which rotates in the direction of arrow A and on which an image is formed by the color material particles 1 is provided.
Along the rotation direction A of the image carrier 2, between the image signal input device 3 and the color material particle removing device 5 as color material particle removing means,
A coloring material particle supply device 4 serving as a coloring material particle supplying means is provided. Prior to the description of the first embodiment shown in FIG. 1, the basic mechanism in image formation of the present invention (that is, the part of the A technology in the configuration of the present invention) will be described first.

FIG. 2A is a diagram (A) of the surface of the drum-shaped image carrier 2 as viewed from directly above, and FIG. The image carrier 2 includes a support layer 201 and periodically arranged holes 202.
and a porous layer 202 having a. Here, the image carrier 2 has a multilayer structure, but may have a single-layer structure as long as it has at least a perforated portion. The arrangement period of the holes 202a of the perforated layer 202 is determined by the image resolution 60
In the case of 0 dpi, the period is 40 μm. Hole 202a
Is a hole diameter smaller than the pixel width of 40 μm, for example, 13 μm
These are regularly and discretely two-dimensionally arranged on the surface of the image carrier 2. The unit pixel area 204 is
The image forming apparatus includes an adhesive force generating portion 205 where the adhesive force with the color material particles changes when an image signal is input, and a pixel region 206 other than the adhesive force generating portion.

The hole 202a is filled with a hot melt adhesive as an adhesive force generating material. Hot-melt adhesives have the characteristic that the viscosity sharply decreases due to heat melting, and the adhesive force sharply increases accordingly. FIG. 3 shows the temperature dependence of the viscosity of the hot melt adhesive. The measurement limit of viscosity is 100
000 mPa · s, and the hot melt adhesive has a certain hardness exceeding the measurement limit at room temperature. Further, it can be seen from FIG. 3 that the viscosity starts to rapidly decrease around 150 ° C. as the temperature increases, and becomes almost constant at around 180 ° C. That is, the softening point of the hot melt adhesive is 150 ° C.
It is near.

In this embodiment, a polyamide hot melt adhesive DA3251 manufactured by Nogawa Chemical Co., Ltd. was used as the hot melt adhesive. However, as long as it has a property of rapidly decreasing its viscosity around the above-mentioned softening point, specifically in the range of room temperature to 300 ° C., more preferably in the range of 40 to 200 ° C., Even a melt adhesive can be used. As such a hot melt adhesive, for example, an elastomer hot melt adhesive DA3051 manufactured by the same company is used.
J, polyester hot melt adhesive DH511L,
EVA hot melt adhesive DA574B, modified polyolefin hot melt adhesive 3120B, DA313
0 and the like.

All holes 202a on the surface of the image carrier 2 are filled with a hot melt adhesive so that the color material particles 1 can be selected for attachment. Examples of the method for filling the hot melt adhesive include the following methods. First, after a hot melt adhesive in a molten state is uniformly applied to the entire surface of the image carrier 2, the hot melt adhesive is cooled and solidified. By using a hot-melt adhesive having high brittleness during solidification, the surface of the image carrier 2 is rubbed with a blade-like member, so that the hot-melt adhesive except for the hot-melt adhesive filled in the holes 202a is removed neatly. .

The image forming apparatus shown in FIG. 1 includes an image signal input device 3. The image signal input device 3 is a light irradiation device based on an image signal, for example, 600 dpi.
It is a considerable LED element or semiconductor laser. The output light stimulus is applied to the hot melt adhesive filled in the hole 202a based on the image signal. If a high-efficiency light-absorbing substance such as phthalocyanine is uniformly dispersed in the hot-melt adhesive, it is mainly responsible for light absorption and heat energy generation, and changes the melting of the hot-melt adhesive. Note that the support layer 201 and the porous layer 202 are formed using polyimide, polyamide imide, polysulfone, or the like having high heat resistance because the support layer 201 and the porous layer 202 need to withstand the temperature rise of the high-efficiency light-absorbing substance.

The phenomenon that occurs when the rotation of the image carrier 2 and the light irradiation of the image signal input device 3 are not sufficiently synchronized to cause a shift Δx will be examined in detail. FIG. 4A shows the relationship between the irradiation energy to the hot-melt adhesive and the adhesive force Fa of the hot-melt adhesive, and FIG. 4B shows the change in the irradiation energy to the hot-melt adhesive due to the irradiation position shift. Indicates the status. The state of (C) in (B) is a state in which the irradiation position does not shift, the energy of the hatched portion acts on the hot melt adhesive filled in the hole 202a, and the color is changed as shown in (C) of (A). The adhesive force Fa1 necessary for holding the material particles is sufficiently obtained. Even if the irradiation position shifts as shown in (B) and (A) of (B), if the irradiation energy has reached a certain threshold or more, (A) and (B) of (A) As shown in ()), the adhesion Fa1 required for holding the adhesion of the coloring material particles is sufficiently obtained. That is, when the irradiation energy exceeds a certain threshold value, the adhesive force Fa of the hot melt adhesive to the coloring material particles sharply increases. This is because, as shown in FIG. 3, the viscosity of the hot-melt adhesive shows a sharp change at a certain temperature (about 150 ° C.), and the adhesive force greatly depends on the viscosity. Therefore, the adhesive strength of the hot melt adhesive filled in the holes 202a in the target pixel can be rapidly changed as long as the spot is irradiated with light at a certain area or more.

FIG. 5 shows the difference between the conventional technique and the present embodiment (A technique) in the case of various image signal input position shifts. This figure shows an image input signal, a cross-sectional structure near the surface of the image carrier (a cross-section of a non-porous layer in the prior art, a cross-section of a perforated layer in the present embodiment), and color material particles on the surface of the image carrier after input of an image signal. And the cross-sectional state near the surface of the image carrier after the supply of the colorant particles (near the non-porous layer in the prior art, near the perforated layer in the present embodiment) so that their relative positional relationships can be understood. It is shown.

In the prior art, the image carrier does not have a perforated layer, and the entire surface is a site where adhesive force can be generated. Cause misalignment. On the other hand, in the present embodiment, the portions where the adhesive force can be generated are regularly arranged in a discrete manner, so that the portions where the adhesive force is generated do not cause displacement and are generated around the pixel central axis.

Returning to FIG. 1, the description will be continued. The hot melt adhesive filled in the hole 202a into which the light stimulus has been input is
Before returning from the molten state to the solidified state, the coloring material particle supply device 4
Is used to supply the color material particles 1. The colorant particles 1 easily adhere to the hot melt adhesive in the image area because the hot melt adhesive is in a hot-melt state and has increased adhesive force by the above-described process.

Inside the color material particle supply device 4, the color material particle holding / supplying roll 4 h rotates in a group of color material particles deposited on the bottom of the color material particle supply device 4, thereby holding the color material particle holding device. The coloring material particles 1 adhere to the surface of the supply roll 4h.
However, in this state, it does not mean that there is no adhesion on the surface of the color material particle holding / supplying roll 4h without a gap.
As shown in (A), the color material particles 1 cannot be supplied to all the image portions, that is, the portions where the adhesive force has occurred. Therefore, even when a solid image signal is input, FIG.
Image omission occurs as indicated by the broken line in FIG. Therefore, it is important to dispose a pressure roll (pressure applying member) 4j that rotates while applying pressure to the color material particle holding and supplying roll 4h, thereby solving this problem.

The operation of the pressure roll 4j is as follows. Although the layer of the color material particles 1 on the surface of the color material particle holding and supplying roll 4h (hereinafter, may be simply referred to as “color material particle layer”) has a gap, the normal line of the surface of the color material particle holding and supplying roll 4h Focusing on the direction, the color material particle layer is not a single layer but a few layers.
The layers are in a multi-layer state. Since there is a cohesive force between the color material particles, it is difficult to make the color material particle layer a 100% single layer state only by the adhesive force without using the electrostatic force or the magnetic force. Therefore, in the case of the present embodiment, the color material particles 1 at the positions of the second and third layers are moved to the gaps of the first layer by pressing the pressure roll 4j as shown in FIG. This makes it possible to adhere the color material particles 1 to the surface of the color material particle holding / supplying roll 4h without gaps, and as a result, it is possible to obtain an image without image omission as shown in FIG.

FIGS. 7A and 7B are side views showing the periphery of the color material particle holding / supplying roll 4h and the pressure roll 4j and their movements used in the present embodiment ((A) is a normal state, (B) is an image bearing member). FIG. 8 is a front view showing a normal state of the color material particle holding / supplying roll 4h pressed by the body (in FIG. 8, the configuration around the pressure roll 4j is omitted). .

The color material particle holding / supplying roll 4h rotates in the driven direction with the image carrier 2 (in the present invention, "rotation in the driven direction" means not only the case of completely driven rotation but also the case of rotating both independently. Or the case where both surfaces have a speed difference and the other slides on one surface, that is, the concept encompasses all that rotate in the same direction as the driven rotation regardless of the rotation speed.) . The color material particle holding / supplying roll 4h may be driven to rotate with the image carrier 2. However, if the torque required for driving the image carrier 2 is excessively increased, a color material particle holding / supplying device (not shown) is used. The roll 4h may be driven.

Since the drum-shaped image carrier 2 has a certain degree of eccentricity due to manufacturing, when the absolute position of the color material particle holding / supplying roll 4h is fixed, the gap with the surface of the image carrier 2 is reduced. Change. This may cause fluctuations in the pressure applied to the image carrier 2 by the color material particle holding and supplying roll 4h, that is, fluctuations in the pressure applied to the color material particle layer. Therefore, in this embodiment, the first applied pressure adjusting means 410 is used so as not to change the relative positional relationship between the portion of the color material particle holding / supplying roll 4h facing the image carrier 2 and the surface of the image carrier 2.

The first applied pressure adjusting means 410 includes a pressure applying member base 400, a gap adjusting main spring 40.
1, a gap adjusting sub-spring 401b, an image carrier pressing rod 402, a pressure roll holder 403, a roller 404, a rod stretching member 305, and a dash pod mechanism (not shown).

The roller 404 arranged at the tip of the image carrier pressing rod 402 is pressed against a non-image portion at the longitudinal end of the image carrier 2. The image carrier pressing rod 402 and the pressure applying member base 400 are connected to a gap adjusting sub-spring 401b and a dash pod (d not shown).
, and a connection via an “Ashpot” mechanism. The image carrier pressing rod 402, the roller 404, the gap adjusting sub-spring 401b, and the dash pod mechanism are disposed at both ends in the longitudinal direction of the image carrier 2, and the pressure applying member base 4 is provided.
It is stretched by 00. With this configuration, even if the roller 404 is pressed by the image carrier 2 as shown in FIG.
The relative position of the portion closer to the image carrier 2 than 02 does not change.

A rod tensioning member 405 connected to the image carrier pressing rod 402 and a pressure roll holder 403 for rotatably holding the color material particle holding / supplying roll 4h from the longitudinal direction are provided by a gap adjusting main spring 401.
And a dash pod mechanism (not shown). By adopting such a configuration, it is possible to absorb the fluctuation of the applied pressure of the color material particle holding and supplying roll 4h due to the eccentricity of the image carrier 2.

In this embodiment, the second applied pressure adjusting means of the same mechanism as the first applied pressure adjusting means 410 (the pressure roll holder 407, the gap adjusting sub-spring 401c and the dash pod mechanism, but without rollers). Using 420, the pressure applied by the pressure roll 4j to the color material particle holding / supply roll 4h is adjusted. therefore,
The relationship between the pressure between the pressure roll 4j and the color material particle holding / supplying roll 4h and the pressure between the color material particle holding / supplying roll 4h and the image carrier 2 can always maintain a stable relationship. Becomes

In this embodiment, the surface of the pressure roll 4j is coated with a fluororesin in order to prevent the color material particles 1 from adhering, and has a high hardness.

In this embodiment, the pressure roll 4j
The cleaning blade 4k rubs against the pressure roll 4j as shown in FIG. 1 so as to be immediately peeled off even when the color material particles 1 adhere to the surface (not shown in FIG. 7). ). The cleaning blade 4h is set at a position distant from the abutting portion so that the separated coloring material particles 1 do not fly and move directly to the abutting portion between the coloring material particle holding and supplying roll 4h and the image carrier 2. I do.

Further, in this embodiment, a color material particle layer thickness adjusting blade 4m is also provided to adjust the thickness of the color material particle layer attached to the color material particle holding and supplying roll 4h.
If the thickness of the color material particle layer is adjusted to be substantially constant, the effect of the present invention can be more effectively achieved by strongly pressing the pressure roll 4j against the color material particle holding and supplying roll 4h.

The process speed of the color material particle holding / supplying roll 4h (the "process speed" in the present invention refers to the progress speed of the roll surface due to the rotation of the roll).
It is desirable to set the process speed higher than the process speed of the image carrier 2. The gap is considerably replaced by the color material particles 1 on the surface of the color material particle holding and supplying roll 4h by moving the color material particles 1 of the second and third layers by the pressure roll 4j to the first layer. However, the arrangement of the color material particles 1 is not regular but random, and there is a possibility that there is a point on the image carrier 2 that is inconsistent with the adhesive force generation site 205 arranged. Therefore, the process speed of the color material particle holding / supplying roll 4h is set to be higher than the process speed of the image carrier 2 so that the image carrier 2
It is preferable to increase the chance of supplying the coloring material particles 1 to the upper side and increase the probability that the coloring material particles 1 can come into contact with the adhesive force generation part 205.

The image forming apparatus of the present invention is intended for high-speed printing. On the other hand, in the current market, 20pp
High-speed printing of m or more (20 prints per minute is possible) is desired. In this case, assuming that the A4 transverse feed and the inter image are 20 mm, the process speed of the image carrier 2 is about 80 mm / s.

FIG. 9 shows an image forming apparatus of this embodiment,
The vertical axis indicates the development rate (the total number (x) of the adhesive force generation portions 205,
Ratio (y / x) to the number (y) of color material particles in contact with and attached thereto,
On the horizontal axis, the ratio (m / n; sometimes simply referred to as “speed ratio”) of the process speed (m) of the color material particle holding and supplying roll 4h and the process speed (n) of the image carrier 2 is taken.
Two levels (A, A) in which the pressure (hereinafter, abbreviated as “pressure B”) between the image carrier 2 and the color material particle holding and supplying roll 4h is changed.
6 is a graph in which a color material particle supply experiment of B) was performed and the result is plotted. The pressure A in the table is the pressure roll 4
j and the pressure between the coloring material particle holding and supplying roll 4h (the same applies hereinafter).

As shown in FIG. 9, it can be seen that the development rate greatly depends on the speed ratio and the pressure B. That is,
As the pressure B increases from 0.06137 kPa (first embodiment B) to 2.24 kPa (first embodiment A), the developing rate sharply increases, and the developing rate also increases with an increase in the speed ratio. ing.

Of the hot melt adhesives present in the adhesive force generation site 205, the hot melt adhesive in the image area is in a heat-melted state by the above-described process and has an increased adhesive force. Adheres. Due to the adhesion of the color material particles 1, heat conduction from the hot melt adhesive to the color material particles 1 occurs, and the temperature of the hot melt adhesive decreases. At this time, the viscosity and the cohesive force of the hot melt adhesive increase, and as a result, the coloring material particles 1 are more firmly held.

The coloring material particles 1 adhere to the hot melt adhesive in a state close to point contact. As a result, the asynchronism between the rotation of the image carrier 2 and the image signal input device 3 as a light irradiation device is absorbed as described above, and the color material particles 1 are positioned substantially on the central axis of the unit pixel. become.

In the case of the present embodiment, the allowable maximum image signal position shift is 26.5 μm (= {pixel width + adhesive force changing portion width}).
/ 2 = {40 + 13} / 2). On the other hand, the displacement amount of the color material particles 1 from the pixel center axis (= the maximum color material particle position displacement amount) is 6.5 μm (= {adhesive force changing portion width} /
2 = 13/2) is a theoretical value. That is, it can be seen that the obtained image can absorb a large image signal position shift.

FIG. 10 shows the frequency of misregistration measured for 60 color material particles of the image forming apparatus to which the prior art is applied and the image forming apparatus to which the present embodiment (A technique) is applied. (A) is a graph showing the present embodiment (B)
Represents the prior art. As shown in FIG. 10, it can be understood that the image signal input position shift that cannot be absorbed by the conventional technique can be absorbed by the present embodiment. That is, in the case of the present embodiment, the amount of misregistration can be greatly reduced as compared with the conventional method, the degree of variation in misregistration is small, and good behavior control of color material particles can be performed.

FIG. 11 is a schematic view of an image sample formed by the conventional image forming apparatus and an image sample formed by the image forming apparatus of the present embodiment (that is, the “A technique”). FIG.
11A is a conventional technique, and FIG. 11B is an image sample in which an alphabet "T" is formed by an image signal according to the present embodiment. It can be seen that it can be suppressed. The image sample shown in FIG. 11 is a conventional technology in which a hot-melt adhesive is applied to the entire region of a T-shape and irradiated with light to give color material particles 1, and the method of the present embodiment (A technology) is used. Is hole 2
The portion 02a is filled with a hot-melt adhesive and irradiated with light in a T-shape to give coloring material particles 1.

The color material particles 1 used in this embodiment had an average particle size of 40 μm. The preferred particle size of the coloring material particles used in the present invention is 0.1 to 100.
μm, and more preferably 1 to 50 μm.

The particle size distribution of the color material particles 1 was monodisperse. Further, it is preferable that the sphericity of the color material particles be a value as close as possible to 1.00, that is, a material having a spherical shape. In this embodiment, the average sphericity of 1.12 is used. However, the preferable sphericity of the coloring material particles used in the present invention is in the range of 1.00 to 1.80, and more preferably 1 to 1.80. 0.01 to 1.17. In addition,
The definition of sphericity is given by the following equation (1).

[0057]

(Equation 1)

In the above formula (1), s is the actual surface area of the particles, v
Is the volume of the particle, dpv is the equivalent volume sphere diameter of the particle, dps
Represents the equivalent surface area sphere diameter of the particles.

Returning to FIG. 1, the description will be continued. The image forming apparatus shown in FIG. 1 includes a color material particle removing device 5 for removing (unnecessary) color material particles 1 not adhering to the hot melt adhesive from an image on the image carrier 2. . The color material particle removing device 5 is provided with a blade member 5 a having a knife edge shape, and the blade member 5 a is held at a fixed distance from the image carrier 2. The state in which the frictional force due to mechanical scraping of the blade member 5a acts on unnecessary color material particles will be described with reference to FIG.

FIG. 12A shows that an image signal by light irradiation is input to the image carrier 2 by the image signal input device 3 and the color material particles 1 are supplied by the color material particle supply device 4. FIG. 4 is a schematic diagram in which the color material particles 1 are attached only to the hot melt adhesive filled in the holes 202a located at the pixels to which the image signals are input. FIG. 12B shows a state in which the blade member 5a is relatively moved with respect to the image carrier drum, and does not adhere to the hot melt adhesive, that is, the adhesive force with the image carrier 2. Only the color material particles 1 having weak color are removed, and as shown in FIG. 12C, the color material particles 1 remain only in the pixels corresponding to the image signal, and an image is formed by the color material particles 1.

At this time, the adhesive force between the color material particles 1 and the hot melt adhesive in the pixel irradiated with light is represented by F _f , and the adhesion between the color material particles 1 and the hot melt adhesive in the pixel not irradiated with light is determined. when force application to F _n, the removal force of the colorant particles 1 by the blade member 5a such was _{F e, F f> F e} > F
_n must be satisfied. By satisfying this condition, it becomes possible to remove the coloring material particles 1 other than the coloring material particles 1 attached to the hot melt adhesive in the image area. When the blade member 5a is used, the removal force of the coloring material particles 1 is determined by the position of the blade, the blade shape, the elastic modulus of the blade, and the like. In addition to the above-described configuration, the coloring material particle removing device 5 may be configured such that a roll 5b provided with an adhesive / adhesive layer on its surface is driven and rotated relative to the image carrier 2 as shown in FIG. Such a configuration can be cited.

The unnecessary coloring material particles 1 that have not been used for image formation are removed by the coloring material particle removing device 5 shown in FIG. 1, whereby an image is formed on the image carrier 2 by the coloring material particles 1. . Further, it is preferable to perform the immobilization processing by the immobilization processing device 6 so that the color material particles 1 constituting the obtained image do not shift each other, but this is not essential in the present invention. In the present embodiment, a lamination process using an adhesive or an adhesive is performed as the immobilization process.
The lamination process is performed by rubbing the adhesive / adhesive in a molten state against the image carrier 2 with the heat roller 6a that is driven to rotate, and laminating the image surface with the color material particles 1. Adhesives / adhesives that can be used in the laminating process include colorless and transparent modified olefin hot melt adhesives DH597A and DH661 manufactured by Nogawa Chemical Co., Ltd.
EVA-based hot melt adhesive DA731B, which is white, is used. In the present embodiment, DH597A is used.

FIG. 14 is a conceptual diagram (cross-sectional view) showing the surface state of the image carrier 2 before and after the laminating process. In FIG. 14A, the color material particles 1 are immobilized by laminating an image of the color material particles 1 formed on the image carrier 2 with an adhesive / adhesive 30, and the immobilization process is performed. As compared with the case where the image is not transferred, it is possible to prevent the image from being disturbed at the time of the next transfer.

The image on the image carrier 2 having undergone the above process is transferred to a sheet 9 which is an image recording medium to be finally recorded. The paper 9 includes the image carrier 2 and the pressure thermal transfer roller 1.
0, and the heat of the pressure thermal transfer roller 10 is passed through the paper 9 and the color material particles 1 on the image carrier 2 at the same time when the pressure is applied.
And to the adhesive / adhesive 30 which is a laminate layer.
As a result, the color material particles 1 are melted by heat and the viscosity is reduced, so that the color material particles 1 bite into the gaps between the fibers of the paper 9 and are completely fixed. Transfer fixing is performed in this manner.

Next, a second embodiment of the image forming apparatus of the present invention will be described. Note that the second embodiment has almost no difference in configuration from the first embodiment described above, and therefore will be described with reference to FIG. 1 as in the first embodiment. In the second embodiment, as in the first embodiment, while the pressure (pressure A) is applied to the surface of the color material particle holding and supplying roll 4h by the pressure roller 4j, the image is carried by the color material particle holding and supplying roll 4h. The coloring material particles 1 are attached to the surface of the body 2. At this time, pressure is applied between the color material particle holding / supplying roll 4h and the image carrier 2 (pressure B). This embodiment is characterized in that attention is paid to the magnitude relationship between the pressure A and the pressure B. This makes it possible to improve the development rate as compared with the case where the magnitude relationship is not considered.

The reason will be described below. First, the adhesive force F _V to the color material particles 1 which greatly affects the development rate will be described. The adhesive force F _V is obtained by the following equation (2).

[0067]

(Equation 2)

In the above equation (2), h _w is
−van der Waals constant, and z is the minimum distance between the color material particles 1 and the surface of the image carrier 2. This state corresponds to the state shown in FIG. 15A, and the adhesive force at this time is F ₀ .

In this state, when the color material particles 1 move to the contact portion between the pressure roll 4j and the color material particle holding / supplying roll 4h, a pressure (pressure A) is applied from the pressure roll 4j to the color material particle holding / supplying roll 4h. Is done. Then, as shown in FIG. 15B, the deformation of the color material particles 1 and the surface of the color material particle holding and supplying roll 4h are deformed, and the contact area between the color material particles 1 and the surface of the color material particle holding and supplying roll 4h increases, As a result, the adhesive force increases (the adhesive force F _p ). Actually, in the region where the pressure A is 21.4 kPa, the deformation of the coloring material particles 1 hardly occurs, and the deformation of the coloring material particle holding and supplying roll 4h mainly contributes to the increase in the adhesive force. When the applied pressure decreases through the contact portion between the pressure roll 4j and the color material particle holding and supplying roll 4h, the deformation also decreases. However, when the pressure falls below a certain pressure range, the elastic energy due to the strain (to reduce the adhesive force). This strain is spontaneously preserved because the increase in the adhesive force due to the increase in the contact area exceeds the increase in the force acting on the contact area. Therefore, the state of the surface of the color material particles 1 and the color material particle holding / supplying roll 4h is shown in FIG.
Then, the adhesive force becomes F ₀ ′, which is larger than the adhesive force F ₀ before the pressure is applied. Thus, the relationship between the applied pressure and the adhesive force becomes a hysteresis. The above process is shown in FIG.

FIG. 16 shows how pressure is applied again at the contact portion between the color material particle holding and supplying roll 4h and the image carrier 2.
(B) and (C). The adhesiveness of the color material particle holding and supplying roll 4h is set lower than the adhesiveness of the hot melt adhesive disposed on the image carrier 2. However, FIG.
Since the process shown in FIG. 5 has been performed, the magnitude of the adhesion force in the state where no pressure is applied between the color material particle holding / supplying roll 4h and the image carrier 2 is reversed (F _s0 ′>).
F _I0 ). Note that the adhesive force between the color material particles 1 and the hot melt adhesive (filled in the adhesive force generating portion 205) disposed on the image carrier 2 is lower than the van der Waals force of the formula (2). it is a resultant force of the liquid bridge force F _L shown in equation (3).

[0071]

(Equation 3)

In the above formulas (3) to (5), R ₀ is the particle size of the color material particles 1, σ is the surface tension, θ is the contact angle, and α is the image carrier 2 passing through the center of the color material particles 1. This is the angle between the surface normal and the straight line connecting the liquid bridge end.

When the pressure B is applied in FIG. 16B, the adhesive force increases as in the case shown in FIG. 15, but in the first embodiment, the pressure B is smaller than the pressure A. Fifteen
No significant increase in the adhesive force occurs as in the case shown in FIG. Therefore, when the pressure B is reduced as shown in FIG. 16 (C), the increase in elastic energy due to strain does not exceed the increase in adhesive force due to the increase in the contact area, and the adhesive force of the color material particles 1 eventually increases. Does not increase or hardly increases. Therefore, the adhesive force between the color material particles 1 and the adhesive force generating portion 205 of the image carrier 2 does not exceed the adhesive force between the color material particles 1 and the color material particle holding / supplying roll 4h.
The color material particles 1 move to the image carrier 2 and are not developed (actually, unevenness of the applied pressure or color material particle holding / supplying roll 4h
Since the pressure disturbance is caused by the presence of the color material particles 1 that could not move to the first layer above, the state is different from that in FIG. 16 and the development rate does not become 0).

Therefore, in the second embodiment, the above-mentioned phenomenon is prevented from occurring by setting the pressure A to be smaller than the pressure B. By reducing the pressure A as shown in FIG. 17A, the color material particle holding and supplying roll 4h is not deformed,
The magnitude of the adhesion after the application of the pressure is such that the adhesion of the color material particle holding and supplying roll 4 h is determined by the adhesion force generation portion 205 of the image carrier 2.
Is lower than the adhesiveness of the hot melt adhesive existing in the above, and the initial setting relationship can be maintained. Therefore, even if pressure is applied again at the contact portion between the color material particle holding / supplying roll 4 h and the image carrier 2, the adhesion force generating portion 20 between the color material particles 1 and the image carrier 2 is applied.
5 can be maintained in a state where the adhesive force between the color material particles 1 and the color material particle holding / supplying roll 4h is larger than the adhesive force between the color material particles 1 and the color material particle holding / supplying roll 4h. Therefore, the color material particles 1 can be favorably developed on the image carrier 2. Further, even if both the pressures A and B are such that hysteresis occurs, if the pressure B is larger than the pressure A, it is possible to develop well as shown in FIG.

In the first embodiment, the pressure A is 21.4 k
Pa and pressure B are 0.06137 kPa and 2.24 kPa
(See FIG. 9), the pressure A was larger than the pressure B under both conditions. However, in the second embodiment, the pressure A was reduced to 0.0068 kPa without changing the pressure B, and the pressure B was changed. It is set smaller than.

FIG. 19 shows the results of the development ratio in the second embodiment and the development ratio in the first embodiment A. It can be seen that the second embodiment, in which the pressure A is smaller than the pressure B at any speed ratio, has a better development rate than the first embodiment A, in which the pressure A is larger than the pressure B.

FIG. 20 is a block diagram of a third embodiment of the image forming apparatus of the present invention. The differences between the second embodiment and the first and second embodiments shown in FIG. 1 will be described. Although the immobilization device 6 is shown in FIG. 1, the immobilization device 6 is not necessarily provided, and in the following embodiments, the immobilization device may not be illustrated in order to avoid complication of the drawing.

In the present embodiment, the image carrier 2 has the structure described below, and is made of a material having a high light transmittance such as transparent glass, polycarbonate, acrylic, or polypropylene as a whole.

The particle diameter of the color material particles 1 used is the same as that of the first embodiment, and the average particle diameter is about 40 μm, which is almost the same as the unit pixel width.
The particle size distribution used was monodisperse. The sphericity of the color material particles 1 is a value as close as possible to 1.00, that is, a spherical shape, which is the same as in the first embodiment.

FIG. 21 shows the surface of the image carrier 2 of this embodiment (in which the adhesion to the color material particles 1 on the image carrier 2 that changes based on the image signal is due to the liquid crosslinking force) from directly above. A view (A) and a sectional view (B) are shown. Since the liquid supplied from the liquid supply device 7 is disposed only in the hole 202a, the porous layer 202 of the image carrier 2 is formed of a water-repellent material, and the hole 202a is filled with a hydrophilic material. I have.

FIG. 22 is a diagram showing an image creation process according to the third embodiment. As shown in FIG. 22A, the liquid supply drum 7a, which is driven by rotation, is relatively moved on the perforated layer 202 of the image carrier 2, so that the droplet 211 is formed only in the hole 202a filled with the hydrophilic material. Is formed.
If the color material particles are supplied in this state, a liquid crosslinking force is generated in the holes 202a of all the pixels, and the color material particles 1 may adhere to one surface.

Further, when the droplet 211 of the non-image portion on the image carrier 2 is irradiated with light stimulation based on the image input signal, the irradiated droplet 211 is heated and vaporized by absorption of light energy (FIG. 22 ( B)). Accordingly, when the color material particles 1 are supplied, the liquid crosslinking force in the non-image area disappears, and the adhesive force distribution is formed imagewise. Then, in the color material particle supply process, if only the color material particles 1 are supplied by a general method, an image omission occurs as shown in a region surrounded by a broken line in FIGS. 30 (A) and 30 (B).

However, in the present embodiment, as in the first and second embodiments, the color material particles 1 are held on the surface, and the color material particles 1 The color material particles are supplied by a color material particle holding / supplying roll 4h that supplies the color material 1 and a roll 4c that applies pressure to the color material particle holding / supplying roll 4h holding the layer of the color material particles 1. Color material particle holding / supplying roll 4h by pressure roll 4c
In order to dispose the color material particles 1 on the surface without any gap, FIG.
An image without image omission as shown in (B) can be formed. In addition, the main component of the liquid for the droplet 211 that is responsible for the liquid crosslinking with the colorant particles 1 used in the present embodiment is ordinary water.

In this embodiment, the water-repellent material forming the porous layer 202 is polytetrafluoroethylene (P
TFE) [contact angle with water (hereinafter “θ”) = 104 °], but in the present invention, any other water-repellent material, for example, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), Tetrafluoroethylene-hexafluoropropylene copolymer (FE
P) [θ = 114 °], tetrafluoroethylene-hexafluoropropylene perfluoroalkylvinyl ether copolymer (EPE) [θ = 84 °], tetrafluoroethylene-ethylene copolymer [θ = 96 °], polychloro Trifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE)
[Θ = 85 °] or the like can be used. In the present embodiment, as the hydrophilic material to be filled in the hole 202a, 6-nylon [θ = 61 °, melting point (hereinafter “T _m ”)
= 215 ° C], but in the present invention, any other hydrophilic material, for example, 6,6-nylon [θ = 6
3 to 70 °, T _m = 260 ° C.].

In this embodiment, the liquid crosslinking force is used for forming an image on the image carrier 2. However, the transfer force of a transfer unit for transferring an image to an image recording medium to be finally recorded, It is also possible to use the liquid crosslinking force as described above for the color material particle removing force by the color material particle removing device that removes unnecessary color material particles that have not been used in the formation. It is not necessary to arrange the droplets discretely, but only to form a uniform liquid film on the desired member surface. If the transfer means or the color material particle removing device of this aspect is used, the member on which the liquid film is uniformly formed is merely rubbed against the image carrier,
Liquid crosslinking force naturally occurs between the color material particles on the image carrier and the surface of the member.

Instead of the liquid bridging force, an electrostatic force, a magnetic force, a chemical bonding force or the like may be applied to the transfer force of the transfer means and the color material particle removing force by the color material particle removing device. In this case, the basic idea is the same.

FIG. 23 is a block diagram of a fourth embodiment of the image forming apparatus of the present invention. The image forming apparatus according to the fourth embodiment shown in FIG. 24 is an example of an image forming apparatus that forms a color image. The components related to each color are denoted by numbers indicating the components, and the colors are distinguished from each other. C (cyan), M (magenta), Y (yellow), and K (black) are provided (colors in parentheses).

The image carrier 2 is arranged around the intermediate transfer belt (intermediate transfer medium) 16 in a tandem manner from cyan 2C to black 2B, and the color material particle supply device 4 also carries the respective image carriers from cyan 4C to black 4B. It is arranged facing the body 2. The image carrier 2 has holes 20 of a perforated layer 202 formed of a water-repellent material as shown in FIG.
A structure in which a hydrophilic material is filled in the portion 2a is employed.

FIG. 24 is a diagram showing an image creating process according to the fourth embodiment. As shown in FIG. 24A, the liquid supply drum 7a, which is rotationally driven, is relatively moved on the perforated layer 202 of the image carrier 2, so that the droplet 211 is only in the hole 202a filled with the hydrophilic material. Is formed.
A light irradiation device (image signal input device 3) that performs light irradiation according to an image signal is arranged outside the image carrier 2. The image signal input device 3 is, for example, 300 to 1200 dp.
A configuration in which an LED element or a semiconductor laser corresponding to i is incorporated therein may be used.

As shown in FIG. 24A, the liquid supply drum 7a driven by rotation is relatively moved on the perforated layer 202 of the image carrier 2, so that the holes 202 filled with the hydrophilic material are formed.
The droplet 211 is formed only in the portion a. In this state, first, the coloring material particles 1 are supplied, a liquid crosslinking force is generated in the holes 202a of all the pixels, and the coloring material particles 1 adhere to one surface (FIG. 24).
(B)). In the present embodiment, in the step of attaching the color material particles 1 to one surface of the surface of the image carrier 2, the surface of the image carrier 2 is held while the color material particles 1 are held on the surface and rotated in the driven direction with the image carrier 2. The color material particles are supplied by a color material particle holding and supplying roll 4h for supplying the color material particles 1 to the toner, and a roll 4c for applying pressure to the color material particle holding and supplying roll 4h holding the layer of the color material particles 1. However, the details are the same as in the first or second embodiment.

The image signal input device 3 emits light based on an image input signal sent from an image signal processing device (not shown),
When the rear surface of the image carrier 2 is irradiated, the light stimulus
The liquid droplets 211 which reach the surface and are present between the color material particles 1 and the image carrier 1 in the non-image area are irradiated. The irradiated droplet 211 rises in temperature due to absorption of light energy and disappears by vaporization (FIG. 24C). As a result, the liquid bridging force of the non-image portion also disappears, and the adhesive force distribution on the surface of the image carrier 2 changes like an image. Then, the unnecessary coloring material particles 1 that have lost the adhesive force due to the liquid crosslinking force are removed by the coloring material particle removing device 5, and an image is formed on the surface of the image carrier 2 by the coloring material particles 1 (FIG. 24D )).

As in the case of the first to third embodiments, the color material particles 1 used had a particle size distribution of 40 μm, which is almost the same as the unit pixel width, and a monodisperse particle size distribution. The sphericity of the color material particles 1 is a value as close as possible to 1.00, that is, spherical, and is specifically the same as in the first embodiment. The coloring material particles 1 are supplied by the coloring material particle supply device 4 onto the image carrier 2 on which the droplets 211 are regularly and discretely arranged.

In the step (C) in FIG. 24, the unnecessary coloring material particles 1 that have lost the adhesive force due to the liquid crosslinking force are removed by the coloring material particle removing device 5, and the coloring material particles 1 are left on the surface of the image carrier 2.
Is formed. The color material particle removing device 5 for removing unnecessary color material particles 1 from the surface of the image carrier 2 includes a first
A blade member 5a having a knife-edge shape is provided similarly to that described in the first embodiment.
“a” is held at a fixed distance from the image carrier 2, and a frictional force acts on the unnecessary color material particles 1 by mechanically scraping the blade member 5 a. At this time, only the droplet 211 that has not been subjected to the light stimulus remains on the surface of the image carrier 2.
The adhesive force due to the liquid crosslinking force between the droplet 211 and the color material particles 1 is F _f , the adhesive force of the color material particles at the pixel where the droplet 211 has disappeared due to the light stimulation is F _n , and the color material by the blade member 5 a and the like. Assuming that the removal force of the particles 1 is F _e , F _f > F _e >
F _n must be satisfied. By satisfying this condition, it is possible to remove the coloring material particles 1 other than the coloring material particles 1 attached to the droplet 211 in the image area (FIG. 24).
(D)).

An intermediate transfer belt 16 having an adhesive / adhesive layer on its surface is inserted between the image carrier 2 and a pressure roller 17 as a primary transfer means. At this time, the adhesion / adhesion layer on the surface of the intermediate transfer belt 16 causes the adhesive force between the color material particles 1 generated by the pressing of the pressure roller 17 and the intermediate transfer belt 16 to drop 211 on the image carrier 2. It is made to be larger than the adhesive force between the particles and the color material particles 1.
Then, the color material particles 1 are pressed by the pressure roller 17 between the image carrier 2 and the intermediate transfer belt 16 without causing the color material particles 1 to fly as in the case of electrophotography. Attach to surface. Therefore, the image formed on the image carrier 2 can be moved to the intermediate transfer belt 16 while maintaining a high-definition image state with no positional displacement.

The above operation is performed for four colors of cyan, magenta, yellow, and black, and the intermediate transfer belt 16
Each color image is superimposed on top to form a full color image. At this time, the immobilization processing device 6 prevents each of the primary transfer images on the intermediate transfer belt 16 from being misaligned due to the superposition operation, and facilitates the superposition of the color material particles 1 so that the color material particles 1 are superimposed. Each time an image is transferred to the intermediate transfer belt 16, a lamination process of an adhesive or an adhesive, which is an example of the immobilization process, may be performed. The laminating process is performed by rubbing the rotatable heat roller 61 with the adhesive / adhesive in a molten state against the intermediate transfer body belt 16. Specifically, it can be performed by the method described in the first embodiment.

The present invention has been described with reference to the first to fourth embodiments. However, the present invention is not limited to the above-described embodiments, but may be implemented within the scope of the technical concept of the present invention. It can also be achieved by any of the conventionally known substitution products and configurations substituted by the substitution method.

For example, as an example, the various components described in the first to fourth embodiments can be replaced with each other to carry out the embodiment. Further, for example, the image carrier is not limited to the drum-shaped one, but may be a belt-shaped one.
r Waals force, liquid bridging force, electrostatic force, magnetic force, or chemical bond may be used. External stimuli that change the adhesive force include light, heat, electric field, magnetic field, pressure, and chemical change (oxidation, polymerization). , Hydrogen bonding, etc.). Similarly, the coloring material removing means for removing unnecessary coloring material particles and the image transferring means for transferring an image may use any force.

[0098]

According to the present invention, the pixel position control as performed in the conventional electrophotographic apparatus is not required, and the pixel position of the color material particles is controlled with high precision and autonomous, resulting in image quality deterioration. It is possible to provide an appropriate supply technique of color material particles in the A technique which is an excellent recording technique. The point of the present invention is, as a color material particle supply means, a color material particle holding supply roll that supplies the color material particles to the surface of the image carrier while rotating in the driven direction with the image carrier while holding the color material particles on the surface, A pressure applying member for applying pressure to the color material particle holding / supply roll holding the color material particle layer, and a means for supplying the color material particles by using the pressure applying member. That is, an image of high quality can be formed.
Therefore, the present invention can be applied to black-and-white and color copiers, printers, and facsimile machines as a recording technique capable of high-accuracy pixel alignment, and has a possibility as a printer for mass printing (CRD). . On the other hand, it also has the ability as a color proofer where high image quality is important.

The effects of the present invention will be listed below. 1. Since the color material particles can be attached to a desired position on the recording medium without missing, high definition image quality can be obtained. 2. As a color material particle supply means, a color material particle holding and supply roll that holds the color material particles on the surface and supplies the color material particles to the image carrier surface while rotating in the driven direction with the image carrier, and a layer of the color material particles. The pressure applying member that applies pressure to the held color material particle holding / supplying roll, and only means for supplying color material particles are employed, so that a stable performance is simplified compared to that using electrostatic force or magnetic force. Thus, the image forming apparatus of the present invention is suitable for mass production, and therefore can be reduced in cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram illustrating a first embodiment of an image forming apparatus of the present invention.

FIG. 2 is a plan view (A) and a cross-sectional view (B) showing the surface structure of the image carrier according to the first embodiment.

FIG. 3 is a diagram showing the dependence of the viscosity of a hot melt adhesive on temperature.

FIG. 4 is a diagram illustrating a case in which light irradiation of an input signal causes a position shift with respect to a unit pixel region.

FIG. 5 is a diagram showing a difference in an adhesive force distribution and an image to be formed between the first embodiment (A technique) and the conventional method in an input signal position shift.

FIG. 6: Case where only color material particles are gravity filled (A)
FIG. 9 is a schematic enlarged view showing a difference between the entire solid image sample and a case where a series of color material particle supply and removal cycles is performed (B).

FIGS. 7A and 7B are side views showing the periphery of the color material particle holding / supplying roll 4h and the pressure roll 4j and their movements used in the first embodiment, wherein FIG. 7A is a normal state, and FIG. This shows a state in which the color material particle holding and supplying roll is pressed by the support.

FIG. 8 is a front view illustrating a coloring material particle holding / supplying roll used in the first embodiment and its periphery. It is.

FIG. 9 is a graph in which two levels (A, B) of color material particle supply experiments are performed using the image forming apparatus of the first embodiment while changing the pressure B, and the results are plotted. The vertical axis represents the development rate, and the horizontal axis represents the speed ratio.

FIG. 10 is a diagram showing a difference in a pixel position shift distribution between the first embodiment and a conventional method.

FIG. 11 is a schematic enlarged view showing a difference between an image sample obtained in the first embodiment and an image sample obtained by a conventional method.

FIG. 12 is a view showing a step of removing unnecessary coloring material particles on an image carrier by a coloring material particle removing unit.

FIG. 13 is a schematic cross-sectional view showing an example of a coloring material particle removing unit using the adhesion / adhesive force of the adhesive / adhesive.

FIG. 14 is a schematic sectional view showing a lamination process.

FIG. 15 is a view showing that the adhesive force between the color material particles and the color material particle holding / supplying roll depends on the applied pressure of a pressure roll (pressure applying member).

FIG. 16 shows a change in the adhesive force between the color material particles and the color material particle holding / supplying roll and a change in the adhesive force between the color material particles and the adhesive force generating portion of the image carrier when the pressure B is smaller than the pressure A. FIG.

FIG. 17 shows a change in the adhesion between the color material particles and the color material particle holding / supplying roll and the change in the color material particles and the image carrier in the case of the second embodiment (when the pressure B is larger than the pressure A). It is a figure which shows the adhesive force change with an adhesive force generation part.

FIG. 18 is a diagram illustrating the adhesion between the color material particles and the color material particle holding and supplying roll when the pressure A causes deformation of the color material particles and / or the color material particle holding and supplying roll in the second embodiment. FIG. 7 is a diagram illustrating a change and a change in an adhesive force between a color material particle and an adhesive force generating portion of an image carrier.

FIG. 19 is a graph in which color material particle supply experiments are performed by the image forming apparatuses according to the first embodiment and the second embodiment, and the results are plotted. The vertical axis represents the development rate, and the horizontal axis represents the speed ratio.

FIG. 20 is a cross-sectional configuration diagram illustrating a third embodiment of the image forming apparatus of the present invention.

FIGS. 21A and 21B are a plan view and a cross-sectional view illustrating a surface structure of an image carrier according to a third embodiment. FIGS.

FIG. 22 is a diagram illustrating an image creation process according to the third embodiment.

FIG. 23 is a cross-sectional configuration diagram illustrating a fourth embodiment of the image forming apparatus of the present invention.

FIG. 24 is a diagram illustrating an image process according to the third embodiment.

FIG. 25 is a schematic cross-sectional view showing a state of an electric field formed by a ladder pattern latent image on a photoconductor surface.

FIG. 26 is a diagram showing a change in contrast potential in a spatial field.

FIG. 27 is a partially enlarged perspective view showing the structure of the imaging drum.

FIG. 28. Oce'3125C Euro Colo
FIG. 3 is a schematic cross-sectional view illustrating a configuration of r Copier.

FIG. 29 is a diagram showing a relationship between a unit pixel width, an adhesive force area width, and a color material particle width in the conventional technique and the A technique.

FIG. 30 is a diagram illustrating image defects that may occur when a conventional color material supply device is used in the A technique.

[Explanation of symbols]

1: Color material particles 2: Image carrier 3: Image signal input device 4: Color material particle supply device 4a: Color material particle supply roll 4b: Color material particle supply roll with discretely arranged attachment portions 4h: Color material particle holding supply Roll 4j: Pressure roll 4k: Cleaning blade 4m: Particle layer thickness adjusting blade 5: Color material particle removing device 5a: Blade member 5b: Roll having a surface provided with an adhesive / adhesive layer 6: Immobilization processing device 6a: Heat roller 7: Liquid supply device 7a: Liquid supply drum 9: Paper 10: Pressure thermal transfer roller 16: Intermediate transfer body belt (intermediate transfer medium) 17: Pressure roller 30: Adhesive / adhesive 58: Paper storage cassette 62: Discharge tray 69: Dielectric layer 70: Ring electrode 71: Insulating layer 72Y-72K: Yellow-black imaging
Drum 73: Intermediate transfer drum 74Y to 74K: (Yellow to Black) developing roll 201: Support layer 202: Perforated layer 202a: Hole 204: Unit pixel area 205: Adhesive force generating part 206: Pixel area 400: Pressure applying member Base 401: gap adjusting main spring 401b: gap adjusting sub-spring 401c: gap adjusting sub-spring 402: image carrier pressing rod 403: pressure roll holder 404: roller 405: rod tension member 407: pressure roll holder 410: first Applied pressure adjusting means

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Satoshi Usui 430 Green Tech Nakai, Nakai-cho, Ashigagami-gun, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. Inside (72) Inventor Yoshiro Yamaguchi 430 Green Tech Nakai, Nakai-cho, Ashigara-gun, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Takefumi Noguchi 430 Green Tech Nakai, Nakai-cho, Ashigaruga-gun, Kanagawa Fuji Xerox Co., Ltd. Terms (reference) 2C065 AA01 AB09 AB11 AC01 AE01 DA33 2H030 AA01 BB02 BB23 BB38 BB42

Claims (5)

[Claims] 1. An image carrier having an image formed of color material particles formed on a surface thereof, wherein the unit pixel is disposed in each unit pixel area when the surface of the image carrier is divided into a large number of pixel areas. An image carrier having an area smaller than the area, including a viscoelastic substance whose adhesive force with the color material particles changes by an external stimulus, and having an adhesive force changing portion capable of adhering the color material particles to the center thereof. A body, by inputting an external stimulus according to an image signal to the image carrier, an image signal input means for forming an image on the surface of the image carrier by an adhesive force distribution with color material particles; Color material particle supply means for supplying color material particles to the image carrier surface, and an image formed by the color material particles formed on the image carrier surface,
Transfer means for transferring the image to an image recording medium on which an image is finally recorded, directly or with a predetermined intermediate transfer medium interposed therebetween, wherein the color material particle supplying means comprises: Color material particle supply roll for supplying color material particles to the image carrier surface while rotating in the driven direction with the image carrier and the color material particle supply roll holding a layer of color material particles An image forming apparatus, comprising: a pressure applying member for applying pressure to a member; 2. An image carrier having an image formed of color material particles formed on a surface thereof, wherein the unit pixel is disposed in each unit pixel area when the surface of the image carrier is divided into a plurality of pixel areas. An image carrier having an area smaller than the area, including a viscoelastic substance whose adhesive force with the color material particles changes by an external stimulus, and having an adhesive force changing portion capable of adhering the color material particles to the center thereof. A body, by inputting an external stimulus according to an image signal to the image carrier, an image signal input means for forming an image on the surface of the image carrier by an adhesive force distribution with color material particles; Color material particle supply means for supplying color material particles to the image carrier surface, and an image formed by the color material particles formed on the image carrier surface,
Transfer means for transferring the image to an image recording medium on which an image is finally recorded, directly or with a predetermined intermediate transfer medium interposed therebetween, wherein the color material particle supplying means comprises: Color material particle supply roll for supplying color material particles to the image carrier surface while rotating in the driven direction with the image carrier and the color material particle supply roll holding a layer of color material particles An image forming apparatus, comprising: a pressure applying member for applying pressure to a member; 3. An image carrier on which an image of color material particles is formed on a surface, wherein the unit pixel is disposed in each unit pixel area when the surface of the image carrier is divided into a large number of pixel areas. An image carrier having an area smaller than the area, including a viscoelastic substance whose adhesive force with the color material particles changes by an external stimulus, and having an adhesive force changing portion capable of adhering the color material particles to the center thereof. A body, by inputting an external stimulus according to an image signal to the image carrier, an image signal input means for forming an image on the surface of the image carrier by an adhesive force distribution with color material particles; Color material particle supply means for supplying color material particles to the image carrier surface, and an image formed by the color material particles formed on the image carrier surface,
Transfer means for transferring the image to an image recording medium on which an image is finally recorded, directly or with a predetermined intermediate transfer medium interposed therebetween, wherein the color material particle supplying means comprises: A color material particle supply roll for supplying color material particles to the surface of the image carrier while rotating in the driven direction with the image material on the surface, and the color material particle supply roll holding a layer of color material particles An image forming apparatus, comprising: a pressure applying member for applying pressure to a member; 4. The image forming apparatus according to claim 1, wherein a process speed of the color material particle holding / supplying roll is set higher than a process speed of the image carrier. 5. The apparatus according to claim 1, wherein a pressure applied to the color material particle holding and supplying roll by the pressure applying member is set to be smaller than a pressure applied to the image carrier by the color material particle holding and supplying roll. 5. The image forming apparatus according to any one of claims 1 to 4.