JP3992414B2 - Image forming method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, a recording liquid having a predetermined concentration and / or a predetermined color is generated by changing a mixing ratio of the image forming liquid and a transparent liquid which is substantially transparent after drying based on the image signal. The present invention relates to an image forming method for guiding an image receptor to form an image, and an apparatus.
[0002]
[Prior art]
In U.S. Pat. No. 3,416,153 (hereinafter referred to as Prior Art Document 1), unnecessary droplets are removed by passing charged ink droplets generated continuously at regular intervals through an electric field modulated by an image signal. It is shown that an image is formed by deflecting and selectively landing on an image support. This method is called a continuous ink jet method because ink droplets are continuously ejected.
[0003]
U.S. Pat. No. 3,946,398 (hereinafter referred to as Prior Art Document 2) discloses a recording medium in which ink is pushed out by deformation of a piezo vibrator modulated by an image signal, and the pushed ink droplet is ejected from an orifice. What is landed on is shown. This method is called a piezo ink jet method.
[0004]
In U.S. Pat. No. 4,490,728 (hereinafter referred to as Prior Art Document 3), ink is rapidly expanded by heating of a heater modulated by an image signal, and ink is ejected from an orifice by the gas of the rapidly expanded ink. What is landed on the recording medium is shown. This method is called a thermal ink jet method because ink droplets are ejected by heat.
[0005]
In U.S. Pat. No. 4,109,282 (hereinafter referred to as Prior Art Document 4), a valve called a flap valve is provided in a flow path for guiding two liquids of a clear ink and a black ink to a substrate for image formation. A printing apparatus is disclosed in which the flow path of each ink is opened and closed by displacing the valve, and the two liquids are mixed to a desired concentration and transferred onto a substrate. As a result, an image having the same gray scale information as the image information displayed on the TV screen can be printed out.
[0006]
Here, it is disclosed that a voltage is applied between a valve of a flap valve and an electrode provided on an opposite surface thereof, and the valve is displaced by mechanically deforming the valve itself by its electrostatic attraction. Yes. Further, the ink is sucked out from the tip of the flap valve to the paper by a capillary phenomenon acting on the ink between the fibers of the print paper.
[0007]
Japanese Patent Laid-Open No. 63-291663 (hereinafter referred to as Prior Art Document 5) describes mixing of two liquids of dark and light in a coating head, continuously ejecting them from a slot, and onto a web transported opposite to the slot. A continuous application of liquid is shown. That is, there is no generation of foreign matters with a uniform coating film pressure over the entire coating width, and a coating solution having a concentration gradient in time with respect to the running direction of the web is continuously applied, and is uniform in the width direction. It can be applied by thickness.
[0008]
[Problems of the prior art]
According to the method (continuous ink jet method) disclosed in the prior art document 1, it is possible to remove an unnecessary droplet by modulating an electric field and draw an arbitrary image. It is necessary to provide a mechanism for independently modulating the electric field for each nozzle provided, which makes it difficult to reduce the size of the nozzle. For this reason, it is difficult to form a large number of nozzles corresponding to the pixels at high density. Further, only a part of the continuously ejected droplets is used for image formation, and there is a problem that it is not suitable for high speed because it is removed without using many other droplets. Furthermore, since ink is ejected continuously, there is a lot of wasted ink, and there is a problem that the obtained print is expensive.
[0009]
According to the method (piezo ink-jet method) shown in the prior art document 2, it is possible to draw an arbitrary image by ejecting only the droplets used for image creation, and only the necessary ink is ejected. There is no waste and a relatively inexpensive print can be obtained. However, in order to achieve high image quality, it is necessary to arrange the nozzles at high density. In this case, there is a problem that the image is disturbed by the interaction of the flying ink droplets.
[0010]
According to the method (thermal ink jet method) shown in the prior art document 3, it is possible to draw an arbitrary image as in the case of the piezo ink jet method. Can be obtained. However, if the nozzles are made high density in order to achieve high image quality, there is a problem that the image is disturbed by the interaction of flying ink droplets. Further, since all of the above prior art documents 1 to 3 fly a droplet at high speed and hit the image receiving paper, when the droplet collides with the image receiving paper, a part thereof is not captured by the image receiving paper but becomes a fine mist. It has also been pointed out that it scatters and leaks into the installation environment of the printing apparatus and contaminates the environment.
[0011]
According to the method disclosed in Prior Art Document 4, since the ink ejected from the nozzles is applied directly onto the paper, if there is paper thickness or paper irregularities, the image is faithfully reproduced with respect to the electrical signal. However, there is a problem that it cannot be reproduced on paper. For this reason, it has not yet been used in earnest. Further, since the ink used is limited to two types, there is a problem that a color image cannot be recorded. Furthermore, because ink is drawn by the capillary action that acts between the ink and paper fibers, it is easily affected by the paper quality. When the paper quality changes, the image quality changes, and the same quality paper is used. Even in this case, there is a problem that the image cannot be faithfully reproduced due to partial non-uniformity of the fiber structure.
[0012]
According to the method disclosed in Prior Art Document 5, an image having a density gradient in the running direction of the web to be coated can be formed, but the density in the width direction of the web (direction orthogonal to the running direction). It cannot have a gradient. For this reason, it is impossible to apply a coating liquid whose color and density change for each pixel in accordance with the image signal.
[0013]
In order to solve the problems of the conventional system, the inventors of the present application have studied a system in which the recording liquid is transferred to the image receptor as a continuous flow. This method uses an image forming liquid in the recording head and a transparent liquid that is substantially transparent after drying. Mixing ratio Is generated based on the image signal, and the recording liquid is applied to the image receptor as a continuous flow. In this case, it is necessary to obtain a good image quality that the recording liquid ejected from the recording liquid ejection port corresponding to each pixel is transferred to the image receptor in synchronization with the image signal.
[0014]
On the other hand, when the recording liquid temporarily accumulates between the recording head and the image receptor to form a bead (liquid reservoir), the stream line of the recording liquid may be disturbed in the bead. For example, a recording liquid vortex may occur in the bead. When such streamline disturbance occurs, the recording liquid cannot be accurately transferred to the image receptor in synchronization with the image signal, and the image is disturbed or the image quality is deteriorated.
[0015]
OBJECT OF THE INVENTION
The present invention has been made in view of such circumstances, and there is provided an image forming liquid and a transparent liquid that is substantially transparent after drying. Mixing ratio In the case where an image is formed by transferring the recording liquid, which has been changed based on the image signal, to the image receptor as a continuous flow, it is possible to improve the image quality by preventing the streamline of the recording liquid from being disturbed. It is a first object to provide an image forming method that can be used. It is a second object of the present invention to provide an image forming apparatus that is directly used for carrying out this method.
[0016]
[Structure of the invention]
According to the present invention, a first object is to provide an image forming liquid for finally forming an image and a transparent liquid that is substantially transparent after drying. Mixing ratio The recording liquid in which the recording liquid is changed based on the image signal is continuously discharged as a continuous flow from the recording liquid discharge port provided independently for each pixel of the recording head, and the recording liquid is moved relative to the recording head. An image forming method for forming an image by continuously transferring to a receptor, Mixing ratio An undercoat liquid positioned on a surface in contact with the surface of the image receptor is laminated on the recording liquid controlled based on an image signal, and a bead of the undercoat liquid is formed at a position where the undercoat liquid meets the image receptor. While Downstream from this bead Said Recording liquid On the image receptor Migrate The stream line of the recording liquid is allowed to be disturbed on the upstream side in the bead while the stream line of the recording liquid is Downstream of This is achieved by an image forming method characterized in that it is prevented from being disturbed.
[0017]
According to the present invention, a bead is formed by laminating an undercoat liquid at a position in contact with the surface of the image receptor of the recording liquid. Downstream of A stable undercoat liquid flow without any disturbance is generated, and a recording liquid is placed on the stable underflow of the undercoat liquid and transferred to the image receptor. If the supply amount of the undercoat liquid is made substantially constant without being modulated by the image signal, the flow of the undercoat liquid is always stable and the image quality is further improved. Even if the undercoat liquid is supplied at a substantially constant supply pressure, the same effect can be obtained. Here, the image forming liquid and the transparent liquid can be continuously applied in a layered manner in the coating thickness direction without being mixed homogeneously. As the undercoat liquid, a transparent liquid that becomes substantially transparent after drying, or an achromatic color liquid that becomes substantially achromatic after drying (for example, white or gray) is suitable.
[0018]
If a plurality of recording liquid discharge ports are provided side by side in the width direction of the image receptor, and the undercoat liquid is discharged from a slit-like undercoat liquid discharge port parallel to the parallel arrangement direction of the recording liquid discharge ports, the undercoat liquid is It becomes a strip or film and its streamline is more stable and the image quality is further improved. The recording liquid discharge ports are arranged in parallel for each pixel arranged in the width direction of the image receptor, and the recording liquid discharged from each recording liquid discharge port is integrated into a strip or film and laminated on the undercoat liquid. By doing so, the recording liquid is uniformly placed on the undercoat liquid, and the flow of this laminate is stable and suitable for improving the image quality.
[0019]
The application density of the pixels can be controlled by the mixing ratio of the transparent liquid that is substantially transparent after drying and the image forming liquid. Further, the color can be controlled by the mixing ratio of a plurality of image forming liquids. The plurality of liquids to be used preferably have a property of being applied in a state of being layered in the coating thickness direction, and preferably have a small viscosity difference, specific gravity difference, surface tension difference, and temperature difference.
[0020]
The image receptor can be formed by an intermediate image receptor to which the coating liquid discharged from the coating liquid discharge port is transferred and a final image receptor to which the coating liquid is transferred from the intermediate image receptor. In this case, the undercoat liquid may be a layer in contact with the surface of the intermediate image receptor so as to cover the surface of the final image when transferred to the final image receptor.
[0021]
Also, if another undercoat liquid is laminated so as to be the uppermost layer when applied to the intermediate image receptor, and the other undercoat liquid contacts the surface of the final image receptor when transferred to the final image receptor, The image quality can be improved by preventing the influence of non-uniformity such as the surface state of the final image receptor surface. In addition, when coating is performed using an intermediate image receptor, consideration is given so that the coating solution can be smoothly transferred to the final image receptor when transferred from the intermediate image receptor to the final image receptor. For example, the adhesion force between the intermediate image receptor and the undercoat liquid in contact therewith, or the cohesive force in this undercoat liquid is determined by the cohesion between other liquids and between liquids and the final image receptor and the liquid in contact therewith. Set smaller than any of the adhesive forces.
[0022]
If the undercoat liquid is transparent, an image faithful to the image signal can be obtained regardless of the presence or absence of the intermediate image receptor. If the undercoat liquid in contact with the surface of the final image receptor is achromatic, preferably white, a good image can be obtained regardless of the color of the final image receptor. Furthermore, when the surface of the final image covers the surface of the final image when transferred to the final image receptor, an image in which a uniform color is added to the whole, for example, a sepia tone, is obtained by setting the undercoat liquid to a desired color. be able to.
[0023]
If the adjacent recording liquid discharge ports are deviated from each other in a non-orthogonal direction with respect to the relative movement direction of the image receptor, the interval between adjacent pixels can be narrowed to improve the image quality. In this case, the image shift can be prevented by correcting the image signal in accordance with the deviation amount of the adjacent recording liquid discharge port.
[0024]
If the recording liquid and the undercoat liquid are always discharged from the recording liquid discharge opening and the undercoat liquid discharge opening even during the period when the image is not formed, the flow of the liquid becomes stable. In this case, the recording liquid unnecessary for image formation is removed and collected while being transferred from the recording liquid discharge port to the image receptor alone or together with the undercoat liquid.
[0025]
According to the present invention, a second object is to record a recording liquid in which a mixing ratio of an image forming liquid for finally forming an image and a transparent liquid which is substantially transparent after drying is changed based on an image signal. An image forming apparatus that forms an image by discharging from a liquid discharge port and moving to an image receptor that moves relative to the recording liquid discharge port, An undercoat liquid discharge port provided in the recording head for uniformly applying the undercoat liquid to the image receptor and forming a bead of the undercoat liquid at a position where the undercoat liquid meets the image receptor; Pixel by pixel Set in Parallel to the direction substantially perpendicular to the relative movement direction of the image receptor. Continuous Recording liquid discharged continuously Downstream of the bead Lead to image receptor Multiple recording liquid outlets And a discharge amount control means for controlling the supply amount of the image forming liquid and the transparent liquid supplied to each recording liquid discharge port, and the mixing ratio of the recording liquid discharged from each recording liquid discharge port based on the image signal A controller for controlling the discharge amount control means, and the streamline of the recording liquid is disturbed on the downstream side of the bead while allowing the streamline of the undercoat liquid to be disturbed on the upstream side in the bead. It is achieved by an image forming apparatus characterized by preventing.
[0026]
One recording liquid discharge port may be provided for each pixel arranged in the width direction of the image receptor, or a plurality of recording liquid discharge ports are provided in the moving direction of the image receptor for one pixel, and the color differs from each recording liquid discharge port. Alternatively, coating liquids having different properties may be supplied. The recording liquid discharge ports and undercoat liquid discharge ports provided for a large number of pixels are divided into a plurality of groups in the width direction of the image receptor, and from some groups corresponding to the width of the image receptor and the width of the image. The discharge of the recording liquid and the undercoat liquid may be stopped. In this case, wasteful consumption of the recording liquid and undercoat liquid can be prevented, and the amount of recovery processing is reduced when unnecessary liquid that does not contribute to coating is removed and recovered.
[0027]
The liquid can be transferred from the recording head to the image receptor by various methods. For example, the coating liquid discharge port and the undercoat liquid discharge port are opened on the upper surface, the lower surface, or the side surface of the recording head, and the image receptor is moved at a constant interval to the surface having the coating liquid discharge port and the undercoat liquid discharge port. A slot coating method for forming an image can be used.
[0028]
Also, a slide coating method can be used in which an inclined surface that descends toward the image receptor is formed on the upper surface of the recording head, and the recording liquid and the undercoat liquid discharged onto this inclined surface flow down on the inclined surface and lead to the image receptor. It is. The image receptor itself may be a final image receptor such as a printing paper, but may be formed by an intermediate image receptor and a final image receptor. In this case, the intermediate image receptor is interposed between the recording head and the final image receptor and transfers the recording liquid and the undercoat liquid received from the recording head to the final image receptor. There can be things.
[0029]
The discharge amount control means can be formed by a discharge amount control valve provided in a passage from the coating liquid supply path to the coating liquid discharge port. For example, it is formed by a diaphragm valve using a piezo element. This discharge amount control valve is provided for each pixel arranged in the width direction of the recording head, and the flow rate is controlled by any one of the opening degree, the opening time, the number of opening times, or a combination thereof. Further, the discharge amount control means may be formed by a pump having a variable discharge amount. This pump can be composed of, for example, a piezo element and a check valve provided for each pixel arranged in the width direction of the recording head. In this case, the flow rate is controlled by any one or a combination of the operation speed, operation time, operation frequency of the pump.
[0030]
[Action]
Based on the image signal, the controller controls the image forming liquid and transparent liquid that are guided to each recording liquid discharge port. Mixing ratio Control the color and concentration of the mixture. This mixed liquid (recording liquid) is discharged as a continuous flow from the recording liquid discharge port and transferred to the image receptor. As a result, an image is formed on the image receptor. Here, since the recording liquid is applied as a continuous flow, there is no waste in the recording liquid, and a high-quality image can be formed at high speed.
[0031]
The undercoat liquid supplied from the undercoat liquid discharge port is located upstream in a bead (liquid reservoir) generated between the recording head and the image receptor. For this reason, the streamline of the undercoat liquid may be formed so as to be folded back upstream in the bead and then returned to the downstream side, or a vortex may be generated during the folding. However, since no image signal is superimposed on the undercoat liquid, there is no problem even if the flow of the undercoat liquid is temporarily disturbed. The undercoat liquid returns to the downstream side after returning to the upstream side and becomes stable rectification. Therefore, the flow of the recording liquid placed on the rectified undercoat liquid is rectified without being disturbed and stabilized.
[0032]
Embodiment
FIG. 1 is a diagram showing an embodiment by a slot coating method, FIG. 2 is a perspective view showing an internal structure of a recording head used here, FIG. 3 is an enlarged sectional view of the recording head, and FIG. FIG. 5 is a diagram showing an example of the arrangement of the recording liquid discharge ports.
[0033]
In FIG. 1, reference numeral 10 denotes a recording head, and this recording head 10 has a large number of recording liquid discharge ports 12 opened on its upper surface and one slit-like undercoat liquid discharge port 14. On the upper surface of the recording head 10, an image receptor 16 made of recording paper is transferred in one direction (right side) while being pressed by the recording head 10 at a constant pressure. Reference numeral 18 denotes a driving roller which feeds the image receptor 16 in one direction (right side) with the driven roller 20 interposed therebetween. A tension roller 22 is located on the opposite side of the drive roller 18 and the driven roller 20 with the recording head 10 interposed therebetween. The tension roller 22 applies a certain tension to the image receiver 16 with the image receiver 16 sandwiched between the driven roller 24 and the tension roller 22.
[0034]
Reference numeral 26 denotes a drive motor for the drive roller 18, and 28 denotes a control unit. The recording liquid discharge port 12 of the recording head 10 is provided independently for each pixel in the width direction of the image receptor 16 (direction substantially orthogonal to the transfer direction). From each recording liquid discharge port 12, a mixed liquid, that is, a recording liquid, in which the mixing ratio of the image forming liquid and the transparent liquid substantially transparent after drying is controlled based on the image signal is discharged. Here, the image forming liquid is, for example, black ink, and the transparent liquid is transparent ink. The image density is changed in multiple steps (for example, 256 steps) by changing the mixing ratio while keeping the total volume flow of both substantially constant, and since the total volume flow is substantially constant, it is stably connected to the image receptor. Can be migrated. The mixing ratio is controlled by the control unit 28 as follows.
[0035]
That is, as shown in FIG. 3, an image forming liquid supply path 30 and a transparent liquid supply path 32 are formed in the recording head 10 in the width direction, and each recording liquid discharge port 12 is divided into two by partition walls 34 (FIG. 3). The passages 36 and 38 are partitioned into two passages 36 and 38, and the passages 36 and 38 communicate with the image forming liquid supply path 30 and the transparent liquid supply path 32, respectively. The other ends of these passages 36 and 38 are an image forming liquid discharge port 36A facing the recording liquid discharge port 12 and a transparent liquid discharge port 38A (FIG. 2). The passages 36 and 38 are provided with an image forming liquid discharge amount control valve 40 and a transparent liquid supply amount control valve 42, respectively.
[0036]
A constant pressure image forming liquid (ink) is supplied to the image forming liquid supply path 30 from a pump 44 shown in FIG. In FIG. 4, 46 is a damper that absorbs the pulsation of the discharge pressure of the pump 44 and keeps the discharge pressure constant. 48 is a filter. Similarly, a transparent liquid having a constant pressure is supplied from the pump to the transparent liquid supply path 32, and the configuration thereof is the same as that of the image forming liquid supply system path.
[0037]
These image forming liquid and transparent liquid are supplied to the image forming liquid supply path 30 and the transparent liquid supply path 32 from the image forming liquid supply port 50 and the transparent liquid supply port 52 shown in FIG.
[0038]
Similarly, the undercoat liquid is guided to the undercoat liquid supply path 56 through the undercoat liquid supply port 54 (FIG. 2) by a pump (not shown). The undercoat liquid supply path 56 is formed long in the width direction of the recording head 10, and the slit-like undercoat liquid discharge port 14 is in communication therewith. The undercoat liquid discharge port 14 is located upstream of the recording liquid discharge port 12 with respect to the feeding direction (right direction) of the image receptor 16 as shown in FIGS. For this reason, after the undercoat liquid is uniformly applied to the recording surface of the image receiver 16, a mixed liquid, that is, a recording liquid discharged from the recording liquid discharge port 12 is applied.
[0039]
The image forming liquid discharge amount control valve 40 and the transparent liquid supply amount control valve 42 can have the same structure. For example, a diaphragm valve driven by a piezo element is suitable. The control valves 40 and 42 and the passages 36 and 38 for accommodating the control valves 40 and 42 can be made by using a micromachine manufacturing method to which a technique used in a manufacturing process of a semiconductor element or the like is applied. . In FIG. 2, the recording liquid discharge ports 12 are drawn with a large interval, but in reality, they are provided with an extremely narrow pixel interval.
[0040]
In order to narrow the application interval between the recording liquid discharge ports 12, the recording liquid discharge ports 12 adjacent to each other may be displaced in the feeding direction of the image receiver 16, as shown in FIG. 5A alternately shifts the adjacent recording liquid discharge ports in the opposite direction, and FIG. 5B shows that an appropriate number (for example, four) of the recording liquid discharge ports 12 are sequentially changed in a certain direction. Is arranged. In these FIG. 5, the image receptor 16 is fed to the right. When the recording liquid discharge ports 12 are deviated as described above, the control unit 28 needs to change the operation timing of the control valves 40 and 42 with respect to different pixels according to the deviation amount. is there.
[0041]
According to this embodiment, the control unit 28 determines the open / close timing and open / close time ratio of the control valves 40 and 42 so as to obtain a mixing ratio corresponding to the density of each pixel based on the image signal. To control. As a result, a predetermined amount of image forming liquid and transparent liquid corresponding to each pixel density are discharged from the recording liquid discharge port 12. On the other hand, a predetermined amount of undercoat liquid is always discharged from the undercoat liquid discharge port 14 in the form of a strip, a plane, or a film. For this reason, when the image receptor 16 is fed in a certain direction by the motor 26, first, the undercoat liquid is applied to a uniform thickness and the base is processed. A recording liquid having a predetermined density discharged from the recording liquid discharge port 12 is applied thereon, and as a result, an image whose density changes in a single color is formed on the image receiver 16.
[0042]
In this case, the distance between the recording head 10 and the image receptor 16 depends on the balance between the discharge pressure of the recording liquid and the undercoat liquid discharged from the recording liquid discharge port 12 and the undercoat liquid discharge port 14 and the tension of the image receiver 16. Determined. Within this interval, a liquid pool, that is, a bead B, is formed by the image forming liquid I, the transparent liquid D, and the undercoat liquid U (see FIG. 3). The image forming liquid I in the bead B is neatly transferred to the image receiver 16 without being disturbed so as to form an image without being disturbed.
[0043]
According to this embodiment, as shown in FIG. 3, the streamline of the undercoat liquid U in the bead B bends from the undercoat liquid discharge port 14 to the upstream side (left side) and then returns to the downstream side (right side). Since the undercoat liquid U is transparent, there is no inconvenience even if the streamline is disturbed in the bead B. Since the image forming liquid I and the transparent liquid D are supplied over the undercoat liquid U that has been U-turned and rectified on the upstream side in the bead B, the image forming liquid I is a transparent liquid. It flows without disturbance along with D, and a good image can be formed.
[0044]
Further, in this embodiment, as shown in FIG. 3, the recording liquid discharge port 12 and the undercoat liquid discharge port 14 have their downstream end wall surfaces curved toward the downstream side (right side) along the streamline, and their upstream side. The shape of the wall surface of the tip was pointed toward the downstream side. For this reason, the streamline of the recording liquid is not particularly disturbed, and smoothly flows on the undercoat liquid. Further, since the transparent liquid discharge port 38A (FIG. 3) is located downstream of the image forming liquid discharge port 36A, the transparent liquid D is interposed between the image forming liquid I and the upper surface of the recording head 10. For this reason, even if the transparent liquid D comes into contact with the upper surface of the recording head 10 and a delay occurs, the delay of the image forming liquid I is reduced and the image quality is further improved.
[0045]
In this embodiment, since one image forming liquid and one transparent liquid are supplied to each recording liquid discharge port 12, an image having a single color and changing in density is formed. However, it is possible to form a color image by discharging a plurality of color image forming liquids (for example, four colors of yellow, magenta, cyan and black) from a common recording liquid discharge port.
[0046]
It is desirable to add a fading preventing agent for preventing deterioration of the recording liquid due to ultraviolet rays or oxidation to the undercoat liquid, transparent liquid or image forming liquid. Examples of the anti-fading agent include an antioxidant, an ultraviolet absorber, and a certain metal complex. Examples of the antioxidant include a chroman compound, a coumaran compound, a phenol compound (for example, hindered phenols), a hydroquinone derivative, a hindered amine derivative, and a spiroindane compound. In addition, compounds described in JP-A 61-159644 are also effective.
[0047]
Examples of ultraviolet absorbers include benzotriazole compounds (US Pat. No. 3,533,794, etc.), 4-thiazolidone compounds (US Pat. No. 3,352,681 etc.), benzophenone compounds (Japanese Patent Laid-Open No. Sho 56-56). 2784, etc.) and other compounds described in JP-A Nos. 54-48535, 62-136641, 61-88256, and the like. Further, an ultraviolet absorbing polymer described in JP-A-62-260152 is also effective. US Pat. Nos. 4,241,155, 4,245,018, columns 3-36, 254,195, columns 3-8, JP-A-62-174741, 61 -88256, Japanese Patent Application Nos. 62-234103, 62-31096, Japanese Patent Application No. 62-230596, and the like.
[0048]
Examples of useful anti-fading agents are described in JP-A-62-215272. The anti-fading agent for preventing fading of the dye transferred to the image receiving material may be previously contained in the image receiving material, or may be supplied from the outside to the image receiving material by a method such as transferring from the dye donating material. May be. The above antioxidants, ultraviolet absorbers, and metal complexes may be used in combination. Moreover, you may use said antioxidant, a ultraviolet absorber, and a metal complex as an emulsion.
[0049]
[Other Embodiments]
FIG. 6 is a perspective view of a recording head according to another embodiment. The recording head 10A is formed by opening a downstream side of the recording liquid ejection port 12 in the recording head 10 shown in FIG.
[0050]
According to this embodiment, since the recording liquid discharged for each pixel is continuously integrated in the width direction at the slit-shaped recording liquid discharge port 12A, the recording liquid has a wide band shape, a sheet shape, or a film shape. Applied. For this reason, it becomes possible to apply | coat stably. In addition, the lamination with the undercoat liquid is performed stably, which is suitable for improving the image quality.
[0051]
[Other Embodiments]
FIG. 7 is a conceptual diagram of another embodiment, and FIG. 8 is a perspective view showing the inside of a recording head used here. FIG. 9 is a schematic diagram showing the relationship between the adhesive force and cohesive force of the liquid. This embodiment is of the slot coating type similar to that shown in FIGS. 1 to 6, except that the recording head 10B forms an image on the final image receiver 16B via the intermediate image receiver 16A.
[0052]
The intermediate image receiver 16A has a cylindrical shape, and the recording head 10B supplies the recording liquid I and the undercoat liquid U to the upper edge of the intermediate image receiver 16A. Here, since the recording head 10B is configured in the same manner as that described with reference to FIGS. The recording head 10B is held by the guide posts 100, 100 so as to be movable up and down, and auxiliary rollers 102, 102 attached to both the left and right side surfaces are brought into rolling contact with both ends of the upper edge of the intermediate image receiver 16A, so that the recording head 10B and the intermediate image The distance from the receptor 16A is kept constant.
[0053]
The coating liquid (recording liquid) and the transparent liquid discharged from the recording head 10B are placed on the intermediate image receiver 16A and are conveyed downward by the rotation of the intermediate image receiver 16A in the counterclockwise direction. A final image receptor 16B such as a recording sheet is pressed by the pressure roller 104 and travels at the same speed on the lower edge of the intermediate image receptor 16A. For this reason, the recording liquid and the undercoat liquid on the intermediate image receiver 16A are transferred to the final image receiver 16B. The final image receptor 16B is fed to the right in FIG. 7 at a constant speed by the guide roller 106 and the guide belt 108, and the recording liquid and the undercoat liquid are dried by the heater 110 on the way. Reference numeral 112 denotes a suction box provided between the guide belts 108, which sucks the final image receptor 16 </ b> B onto the upper surface of the guide belt 108 so as to be brought into close contact with the guide belt 108 and transport it.
[0054]
Reference numerals 114 and 114 denote cleaning rollers that are brought into contact with the intermediate image receptor 16A to clean the surface, and 116 and 118 are heaters and charging electrodes, which heat and charge the surface of the intermediate image receptor 16A. A pretreatment is performed to facilitate the adhesion of the recording liquid and the undercoat liquid. Reference numerals 120 and 122 denote a heater and a drying air blowing duct for predrying the recording liquid and the undercoat liquid supplied from the recording head 10B.
[0055]
Reference numeral 124 denotes a liquid recovery blade which serves as a coating liquid recovery means. The blade 124 peels off and collects liquid that is not necessary for image formation from the intermediate image receiver 16A. Since the recording liquid and the undercoat liquid can be constantly discharged from the recording head 10B to stabilize the coating state, the liquid is always supplied, while unnecessary liquid is removed by the blade 124, thereby forming an image. Can be stabilized. A cleaning roller 126 further cleans the surface removed by the blade 124.
[0056]
In the recording head 10B, as shown in FIG. 8, the undercoat liquid discharge port 14 is positioned upstream of the recording liquid discharge port 12 on the intermediate image receiver 16A. That is, in FIG. 8, the intermediate image receptor 16A travels from left to right. Therefore, the undercoat liquid is placed on the intermediate image receptor 16A so as to overlap the recording liquid. When the undercoat liquid and the recording liquid are transferred to the intermediate image receptor 16A, the undercoat liquid comes into contact with the surface of the intermediate image receptor 16A to stabilize the flow of the recording liquid, thereby eliminating the disturbance and improving the image quality. Improve.
[0057]
In order to smoothly transfer the undercoat liquid and the recording liquid applied to the intermediate image receptor 16A to the final image receptor 16B, the following conditions are required. FIG. 9 is a schematic diagram of each layer for explaining the relationship between the adhesive force of the liquid and the cohesive force in the liquid at this time. In this figure, the intermediate image receptor 16A is M, the undercoat liquid is U, the recording liquid is I, the final image receptor 16B is P, and the adhesion force acting between these is F. _MU , F _UI , F _IP And the cohesion force in the undercoat liquid and the recording liquid is F _UU , F _II And At this time, F _MU Each liquid and the surface state of the receivers 16A and 16B are set in advance so that is minimized.
[0058]
Here, the recording liquid may be a homogeneous mixture of the image forming liquid and the transparent liquid. For example, the recording liquid discharge port 12 can be mixed by providing a honeycomb-shaped or pipe-shaped static mixer for stirring the liquid. In the case where the image forming liquid and the transparent liquid are separated and laminated in a layered form without mixing, the intermediate image receptor 16A and the same are divided into the adhesive force between each layer and the cohesive force in each layer as described above. What is necessary is just to make it the adhesive force with the liquid which closely_contact | adheres become the minimum.
[0059]
[Other Embodiments]
FIG. 10 is a cross-sectional view of a recording head according to another embodiment. The recording head 10 </ b> C is used in a slot coating method similar to that in FIG. 7, and the supply amount of the image forming liquid supplied from the image forming liquid supply path 30 is controlled by the image forming liquid discharge amount control valve 40. The transparent liquid is supplied in two layers so as to sandwich the image forming liquid from both sides. That is, one transparent liquid supply path 32A always discharges a fixed amount, and the other transparent liquid supply path 32B discharges from the discharge port 12 by the transparent liquid discharge amount control valve 42 so that stable application can be performed. The total volume flow rate of the liquid and the image forming liquid is controlled to be substantially constant.
[0060]
Here, since the total flow rate of the transparent liquid and the image forming liquid supplied from the transparent liquid supplying paths 32A and 32B and the image forming liquid supplying path 30 is considered to have a substantially constant fluid pressure, the downstream of the transparent liquid supplying path 32A. It is almost determined by the cross-sectional area of the channel on the side. Accordingly, the flow rate of the transparent liquid discharged from the transparent liquid supply path 32A is increased or decreased as the total flow rate of the transparent liquid and the image forming liquid supplied from the transparent liquid supply path 32B and the image forming liquid supply path 30 as other coating liquids increases. Decrease. For this reason, a discharge amount control valve is not required in the flow path of the transparent liquid supply path 32A, and the configuration of the recording head 10C is simplified.
[0061]
Further, the undercoat liquid discharge port 14 is opened upstream of the recording liquid discharge port 12. For this reason, the flow line of the undercoat liquid that is always supplied from the undercoat liquid supply path 56 may be folded upstream in the bead B, but has a three-layer structure in which the image forming liquid is sandwiched from both sides with a transparent liquid. Since the coating liquid is sent over the stable undercoat liquid, image distortion does not occur. Further, since both sides of the image forming liquid are sandwiched by the transparent liquid, the liquid directly contacts the inner wall surface of the recording liquid discharge port 12 becomes the transparent liquid, and the flow of the image forming liquid becomes smooth and the image quality is further improved.
[0062]
[Other Embodiments]
FIG. 11 is a cross-sectional view of a recording head 10D according to another embodiment, and FIG. 12 is a cross-sectional view schematically showing a laminated structure of a coating liquid by the recording head 10D. The recording head 10D is used for forming a color image by the slot coating method described above.
[0063]
The recording head 10D includes four color image forming liquid supply paths 30D (Y), 30D (M), 30D (C), and 30D for yellow (Y), magenta (M), cyan (C), and black (K). (K), four image forming liquid discharge amount control valves 40D for controlling the discharge amounts of these image forming liquids to the passage communicating with the coating liquid discharge port 12D, and the image forming liquids of these colors. And two transparent liquid supply paths 32D for supplying the transparent liquid (D) to both surfaces of these laminates, and a transparent liquid supply amount control valve 42D (Y) for controlling the amount of the transparent liquid supplied to the vicinity of each image forming liquid. , 42D (M), 42D (C), 42D (K) and two transparent liquid supply amount control valves 42D for controlling the transparent liquid supply amount supplied to both surfaces of the laminate. Here, the transparent liquid (D) entering between the image forming liquids of the respective colors is supplied in place of the changed image forming liquid when the supply amount of the image forming liquid is changed, thereby reducing the thickness of the laminate. Has a function to keep it almost constant. Further, the transparent liquid covering both surfaces of the laminated body is set to a constant flow rate regardless of the image signal.
[0064]
The cross-sectional structure of the laminate at this time is as shown in FIG. In this figure, Y, M, C, and K are image forming liquids (inks) of respective colors, and the supply amounts thereof are modulated based on image signals. When the image forming liquids (Y, M, C, K) of each color are stacked in the order of Y, M, C, K from the side closer to the intermediate image receptor 16A as shown in FIG. 11, the stacked body of FIG. Will be located on the intermediate image receiver 16A side. Further, in this laminate, the case where two color image forming liquids overlap in the thickness direction of the coating film is shown. However, by supplying a transparent liquid (D) instead of all the image forming liquids, Of course, two or more colors (three colors or four colors) may be mixed.
[0065]
The surface (front surface side) and the lower surface (intermediate image receptor side) of the laminate are each covered with a transparent liquid (D). In this case, the transparent liquid D (intermediate receptor side) on the lower surface becomes the undercoat liquid (U) and has streamlines that fold back upstream in the bead B, but the recording liquid (I) is downstream of the transparent liquid (D). The streamline is stable without being disturbed. The transparent liquid supply amount control valve 42D may be controlled so that the supply amount of the transparent liquid (D) is controlled by an image signal. In this case, the transparent liquid supplied in the vicinity of each image forming liquid supply passage opening functions to prevent the image forming liquid from adhering to the inner wall of the recording head. Moreover, you may make it apply | coat another transparent liquid (DD) also to the both end surfaces of the width direction of this laminated body. In this case, another transparent liquid supply path may be added to the recording head 10D.
[0066]
In this embodiment, the laminate is formed in the final image receptor 16B and dried because the image forming liquids (Y, M, C, K) and the transparent liquid (D) of each color are applied in an orderly manner and are not mixed with each other. In the obtained image, streaky unevenness corresponding to each color in each pixel can be recognized. In order to remove such unevenness, it is preferable to mix the image forming liquid and the transparent liquid immediately before the recording liquid discharge port 12D of each pixel. For this purpose, for example, a so-called static mixer such as a thin plate honeycomb shape or a pipe type spiral shape is preferably provided in the middle of the mixed solution.
[0067]
[Other Embodiments]
FIG. 13 is a diagram showing an outline of another embodiment, FIG. 14 is a sectional view of the recording head, and FIG. 15 is a diagram showing a layer structure of a coating liquid (recording liquid). This embodiment shows a coating apparatus by a slide coating method.
[0068]
A recording head 10E is provided on one side (left side) of the intermediate image receiver 16A and supplies coating liquid (recording liquid and undercoat liquid) to the intermediate image receiver 16A from this position. At the other side (right side) of the intermediate image receiver 16A, the final image receiver 16B is pressed by the pressure roller 200, and the coating liquid (recording liquid and undercoat liquid) is applied from the surface of the intermediate image receiver 16A at this position. Transferred to final image receptor 16B. Here, the final image receptor 16B is fed almost vertically from the upper side to the lower side by the guide roller 202 and the guide belt 204, and is dried by the heater 206 halfway after the application.
[0069]
As shown in FIG. 14, the recording head 10E has an inclined surface 208 on its upper surface. The inclined surface 208 is inclined so as to descend toward the intermediate image receptor 16A, and its lower edge is horizontal in the width direction and is close to the intermediate image receptor 16A. In the inclined surface 208, an undercoat liquid discharge port 14E, a first recording liquid discharge port 12E1, and a second recording liquid discharge port 12E2 are opened in that order from the lower edge side. The undercoat liquid discharge port 14E has a slit shape continuous in the width direction, and the first and second recording liquid discharge ports 12E1 and 12E2 are provided separately for each pixel.
[0070]
The undercoat liquid used here is supplied from the undercoat liquid supply path 56E, and the adhesive force or cohesive force with the intermediate image receptor 16A is set smaller than the adhesive force or cohesive force of other image forming liquids or transparent liquids. The recording liquid discharge ports 12E1 and 12E2 have three-layer coating liquids (recording liquids) in which the image forming liquids B and A, the discharge amounts of which are controlled by the image forming liquid discharge amount control valve 40E, are sandwiched by transparent liquids from both sides. ) Is discharged. 30E and 30E are supply flow paths for the image forming liquids (A, B), and 32E is a supply path for the transparent liquid supplied to both sides of each image forming liquid (A, B). Reference numeral 42E denotes a transparent liquid supply amount control valve for controlling one of the transparent liquids for the recording liquid discharge ports 12E1 and 12E2.
[0071]
According to this embodiment, as shown in FIG. 15, the image forming liquids A and B are layered while being sandwiched between transparent liquids, flow down the inclined surface 208 in an orderly manner, and are undercoat discharged from the undercoat liquid discharge port 14E. It is placed on the liquid and transferred to the intermediate image receptor 16A together with the undercoat liquid. The image forming liquids A and B controlled in response to the image signal are controlled by correcting the operation timing of the control valves 40E and 42E so that they have the same phase on the intermediate image receptor 16A. In addition, since the undercoat liquid is the lowest layer, even if the flow of the undercoat liquid encountering the intermediate image receptor 16A is disturbed, the recording liquid is rectified and placed on the stable undercoat liquid, so that the image quality is disturbed. There is no.
[0072]
In FIG. 13, reference numerals 210 and 210 denote cleaning rollers, and 212 denotes a heater, which improves the wettability of the liquid by performing a pretreatment on the surface of the intermediate image receptor 16A. Reference numeral 214 denotes an exhaust pump, and 216 denotes a decompression chamber. The decompression chamber 216 faces the coating liquid moving part between the recording head 10E and the intermediate image receiver 16A from below, and air is mixed between the coating liquid and the intermediate image receiver 16A to prevent the image from being disturbed. It is something to prevent. Reference numeral 218 denotes a heater for predrying the applied liquid. Reference numeral 220 denotes a blade as a coating liquid collecting means, and 222 denotes a cleaning roller, which removes and collects a coating liquid that is not necessary for image formation, for example, an unnecessary coating liquid on the front end side or rear end side of an image.
[0073]
[Other Embodiments]
FIG. 16 is a cross-sectional view of a recording head according to another embodiment. This recording head 10F is used for the slide coating method similar to that shown in FIG. 13, and the same parts as those of the recording head 10E shown in FIGS. 14 and 15 is that a recovery switching plate 230 as a coating liquid recovery means and a coating liquid recovery path 232 are added to the inclined surface 208.
[0074]
The recovery switching plate 230 is closed during normal image formation, and a coating liquid is placed on the upper surface of the recovery switching plate 230 to flow down to the intermediate image receiver 16A. Unnecessary coating liquid before and after image formation is guided to the coating liquid collection path 232 by opening the collection switching plate 230. As described above, the recovery switching plate 230 is opened before the coating liquid is transferred to the intermediate image receptor 16A so that the recovery can be performed. In addition, the structure is simple and suitable for miniaturization.
[0075]
When forming a final image whose width is narrower than the effective recording width of the recording head 10F, it is sufficient to discharge the coating liquid (image forming liquid, transparent liquid, and undercoat liquid) by a necessary width. For that purpose, the control valve is closed so that unnecessary liquid is not discharged from the recording liquid discharge port, and the discharge port for transparent liquid and undercoat liquid is also grouped into multiple discharge blocks in the width direction, corresponding to the width of the final image It is desirable to selectively discharge liquid from only the portion. In this way, it is possible to reduce the load on the blade 220 (see FIG. 13) and the recovery switching plate 230 for removing and recovering unnecessary liquid and reducing the cleaning load on the intermediate image receptor 16A.
[0076]
[Other Embodiments]
FIG. 17 is a cross-sectional view of a recording head according to another embodiment. The recording head 10I includes a coating liquid discharge port 12I that opens downward. The final image receiver 16 is sent close to the lower part of the coating liquid discharge port 12I and at a predetermined interval. A coating liquid recovery switching plate 280 as a coating liquid recovery means is provided between the coating liquid discharge port 12I and the image receiver 16 so as to be movable forward and backward.
[0077]
That is, the recovery switching plate 280 is formed long in the width direction of the recording head 10I, and has an end edge that enters the coating liquid discharge port 12I below a thin plate shape, and the other end edge is folded upward in an L shape. It is tuned. The upper surface is inclined so as to descend from the thin plate-shaped end edge toward the other end edge. Further, a coating liquid suction port 282 that is long in the width direction of the recording head 10I is opened inside the portion bent in an L shape.
[0078]
Therefore, if the thin plate-like tip of the recovery switching plate 280 is made to enter below the coating liquid discharge port 12I, the coating liquid discharged from the coating liquid discharge port 12I is placed on the recovery switching plate 280 and is L-shaped. It flows to the bent side. Then, the liquid is sucked from the coating liquid suction port 282 and removed and collected. When the recovery switching plate 280 is withdrawn from the lower side of the coating liquid discharge port 12I, the coating liquid discharged from the coating liquid discharge port 12I is transferred to the image receiver 16 and an image can be formed.
[0079]
[Other Embodiments]
When the recording head is not used for a long time, the solute precipitates or solidifies as the liquid solvent evaporates. This causes a problem that the liquid discharge port and the liquid passage of the recording head are clogged. In order to avoid this, it is preferable to flow a liquid (cleaning liquid) for cleaning the recording head at the end of use. Further, when the recording head is not used, it is possible to obtain a great effect by covering the surface of the recording head (particularly the inclined surface) with a cover and preventing the liquid from coming into contact with the outside air. As the cleaning liquid, a liquid that dissolves the solidified component contained in the coating liquid is desirable, but an undercoat liquid or a transparent liquid that becomes substantially transparent after drying can also have this function.
[0080]
For uniform coating, it is effective to control the coating liquid such as the image forming liquid, the transparent liquid, and the undercoat liquid and the ambient temperature around the recording head and the recording head to be the same. In the case of the slot type, it is effective for uniform application that the temperature of the final image receptor or the intermediate image receptor for temporarily holding the coating liquid between the recording head and the intermediate image receptor is the same as that of the coating liquid and the recording head. It is. It is preferable to provide a heat exchange part in the middle of the coating liquid storage tank or the coating liquid feeding pipe so that when the coating liquid is replaced during coating, the coating liquid reaches a predetermined temperature before reaching the recording head. .
[0081]
The above embodiment has been described as forming an image. That is, the description has been made on the assumption that an image is drawn two-dimensionally on a sheet of paper or film. However, the present invention is suitable for the manufacture of industrial products with spatially varying color and density, such as mosaic filters used in image displays such as liquid crystal color displays, that is, color filters in which yellow, magenta, and cyan colors are repeatedly arranged in a mosaic pattern. Can be used. Furthermore, the present invention can also be applied to the manufacture of industrial products that form spatially repeatable patterns.
[0082]
【The invention's effect】
According to the first aspect of the present invention, as described above, a plurality of recording liquids are respectively ejected as a continuous flow from a plurality of recording liquid ejection ports arranged in a direction (width direction) substantially orthogonal to the relative movement direction of the image receptor. Therefore, the amount of wasted ink is small and image formation can be performed at high speed, and it is not necessary to form a different electric field for each pixel, so that the size of the nozzle can be reduced. In addition, the image disturbance due to the interaction between ink droplets as in the ink jet method and the installation environment are not adversely affected, and the image can be stably formed without being affected by the thickness or surface condition of the image receptor. Can do.
[0083]
In this case, the undercoat liquid is laminated so as to be positioned on the surface of the recording liquid in contact with the image receptor, and the flow of the undercoat liquid is rectified in the bead while allowing the streamline of the undercoat liquid to be disturbed upstream in the bead. Since the recording liquid is placed on the undercoat liquid and sent, the streamlines of the recording liquid are not disturbed in the bead, the image is not disturbed, and the image quality can be improved.
[0084]
If the undercoat liquid is not modulated by the image signal and is always supplied at a substantially constant supply rate or supplied at a substantially constant supply pressure, the flow of the undercoat liquid is stabilized and the image quality is further improved. 2, 3). If a plurality of recording liquid discharge ports are provided in the width direction of the image receptor and the undercoat liquid discharge ports are formed in a slit shape in the same direction, the undercoat liquid is discharged in the form of a strip or film, and its flow is stabilized. Since the recording liquid to be placed can be sent stably, the image is further improved.
[0085]
The recording liquid discharge ports are arranged side by side for each pixel, and the recording liquid discharged from each recording liquid discharge port is integrated in the direction in which the coating liquid discharge ports are arranged in parallel and discharged in a strip shape to be stacked on the undercoat liquid. (Claim 5). In this case, the recording liquid discharge port for each pixel may be opened in the slit-shaped recording liquid discharge port, and integrated into the band shape in the slit-shaped recording liquid discharge port.
[0086]
The recording liquid and the undercoat liquid can be transferred from the recording head to the final image receptor via the intermediate image receptor. When the intermediate image receptor is used as described above, the adhesive force or cohesive force of the undercoat liquid contacting the intermediate image receptor surface is set to be smaller than the adhesive force or cohesive force between the other coating liquid layers. It is possible to smoothly transfer the coating liquid from the intermediate image receptor to the final image receptor (claims 7 and 8).
[0087]
For small pixel intervals, the adjacent recording liquid discharge ports may be displaced in the relative movement direction of the image receptor. In this case, image deviation can be prevented by applying temporal correction to the image signal for each pixel corresponding to this displacement. The coating liquid (recording liquid and undercoat liquid) is discharged even during a period in which no image is formed. For example, by continuously discharging a transparent liquid, the liquid is continuously applied to enable stable image formation. 10). In this case, unnecessary recording liquid is removed and collected between the coating liquid discharge port and the image receptor.
[0088]
If the undercoat liquid is a transparent liquid that becomes substantially transparent after drying, an image faithful to the image signal can always be recorded regardless of the presence or absence of the intermediate image receptor. If the undercoat liquid is an achromatic liquid that becomes substantially achromatic after drying, a good image can always be recorded without being affected by the color of the final image receptor.
[0089]
According to the thirteenth aspect of the present invention, an image forming apparatus used directly for carrying out the method of the first aspect can be obtained. The recording liquid discharge port may be provided for each pixel arranged in the width direction of the image receptor (Claim 14). If the recording liquid discharge port for one pixel is divided into a plurality in the moving direction of the image receptor, The recording head can be easily manufactured. Further, if the recording liquid discharge ports for the adjacent pixels are displaced from each other in the moving direction of the image receptor, the interval between the adjacent recording liquid discharge ports is widened, and the productivity of the recording head is improved.
[0090]
If each of the recording liquid discharge ports is a slit-shaped recording liquid discharge port and is continuous in the width direction, the recording liquid can be smoothly ejected in a strip shape. The undercoat liquid discharge port has a slit shape and discharges the undercoat liquid in a strip shape, so that the undercoat liquid can be supplied uniformly and smoothly, smoothing the flow of the undercoat liquid and rectifying the flow of the recording liquid placed on it. To improve the image quality (claim 18). The recording head can be configured in accordance with a coating method such as a slot coating method (claims 19 and 20) or a slide coating method (claim 21). In addition, a means for removing and collecting the coating solution in the middle can be provided. In this case, a more stable image can be formed by continuously discharging the coating solution.
[0091]
The image receptor may be supplied in the form of a sheet or film such as paper directly by a recording head (Claim 23), but the final image receptor such as paper via an intermediate image receptor The coating liquid may be transferred to (Claim 24). In this case, the surface condition of the intermediate image receptor is stabilized by the undercoat liquid to enable good image formation on the intermediate image receptor, and the characteristics of the undercoat liquid are appropriately set to set the coating liquid. This transition from the intermediate image receptor to the final image receptor can be performed smoothly. Therefore, it is possible to form a higher quality image.
[0092]
The discharge amount control means can be formed by a discharge amount control valve provided in a passage from the coating liquid supply path to the coating liquid discharge port. Further, the discharge amount control means may control the discharge amount from each discharge port by a pump provided for each coating liquid discharge port.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment according to a slot coating method.
FIG. 2 is a perspective view showing the internal structure of the recording head.
FIG. 3 is an enlarged sectional view of the recording head.
FIG. 4 is a conceptual diagram of a coating liquid supply path.
FIG. 5 is a view showing an example of arrangement of coating liquid discharge ports
FIG. 6 is a perspective view of a recording head according to another embodiment.
FIG. 7 is a conceptual diagram of another embodiment.
FIG. 8 is a perspective view of the recording head.
FIG. 9 is a schematic diagram for explaining the relationship between the adhesion force and the cohesive force of a coating solution.
FIG. 10 is a cross-sectional view of a recording head according to another embodiment.
FIG. 11 is a cross-sectional view of a recording head according to another embodiment.
FIG. 12 is a cross-sectional view schematically showing a laminated structure of a coating solution
FIG. 13 is a diagram showing an outline of another embodiment.
FIG. 14 is a sectional view of the recording head.
FIG. 15 is a diagram showing the layer structure of the coating solution
FIG. 16 is a cross-sectional view of a recording head according to another embodiment.
FIG. 17 is a cross-sectional view of a recording head according to another embodiment.
[Explanation of symbols]
10, 10A-10F, 10I Recording head
12, 12E, 12I Coating liquid discharge port
12A Slit-like coating liquid discharge port
14, 14E Undercoat liquid outlet
16 Image receptor
16A intermediate image receptor
16B Final image receptor
28 Control unit
30, 30D, 30E, 30I Image forming liquid supply path
32, 32A, 32B, 32D, 32E, 32I Transparent liquid supply path
40, 40D, 40E, 40I Image forming liquid discharge amount control valve
42, 42D, 42E, 42I Transparent liquid discharge amount control valve
124, 220 Blade as coating solution recovery means
230, 280 Recovery switching plate as coating liquid recovery means

Claims (26)

A recording liquid in which a recording liquid in which a mixing ratio of an image forming liquid for finally forming an image and a transparent liquid substantially transparent after drying is changed based on an image signal is provided independently for each pixel of the recording head An image forming method for forming an image by continuously ejecting from a discharge port as a continuous flow and continuously transferring the recording liquid to an image receptor that moves relative to the recording head,
The recording liquid whose mixing ratio is controlled on the basis of an image signal is laminated with an undercoat liquid positioned on a surface in contact with the surface of the image receptor, and the bead of the undercoat liquid is placed at a position where the undercoat liquid meets the image receptor. The recording liquid is transferred to the image receptor on the downstream side of the bead, and the streamline of the recording liquid is allowed to be disturbed on the upstream side of the bead while the recording liquid is streamed. An image forming method characterized by preventing disturbance on the downstream side of a bead. The image forming method according to claim 1, wherein the undercoat liquid is supplied without being modulated by the image signal with a substantially constant supply amount. 2. The image forming method according to claim 1, wherein the undercoat liquid is supplied at a substantially constant supply pressure without being modulated by the image signal. The recording liquid obtained by mixing the image forming liquid and a transparent liquid that is substantially transparent after drying is discharged from a plurality of recording liquid discharge ports arranged in a direction substantially perpendicular to the relative movement direction of the image receptor, and the undercoat liquid is discharged from the recording liquid. The image forming method according to claim 1, 2, or 3, wherein the image forming method is discharged from a slit-like undercoat liquid discharge port parallel to the direction in which the outlets are arranged in parallel. The recording liquid discharge port is divided and arranged for each pixel arranged in a direction substantially orthogonal to the relative movement direction of the image receptor, and the recording liquid discharged from each recording liquid discharge port is arranged in the parallel direction of the recording liquid discharge port. The image forming method according to claim 4, wherein the image forming method is integrated into a belt and laminated on the undercoat liquid. 6. The image forming method according to claim 1, wherein the recording liquid and the undercoat liquid are transferred from the recording head to the final image receptor via the intermediate image receptor. The adhesion between the intermediate image receptor and the undercoat liquid in contact with the intermediate image receptor is determined by the cohesion between the image forming liquid and the transparent liquid that is substantially transparent after drying, and the final image receptor and the coating liquid in contact therewith. 7. The image forming method according to claim 6, wherein the image forming method is set to be smaller than any of the adhesive forces. The cohesion force in the undercoat liquid in contact with the intermediate image receptor surface is determined by the cohesion force in and between the image forming liquid and the transparent liquid substantially transparent after drying, and the final image receptor and these liquids. The image forming method according to claim 6 , wherein the image forming method is set smaller than any of the adhesive forces. The recording liquid discharge ports adjacent to each other are offset from each other in a non-orthogonal direction with respect to the relative movement direction of the image receptor, and the image signal for each pixel is corrected in advance so as to prevent image displacement due to the displacement of the recording liquid discharge port. The image forming method according to claim 1. The recording liquid and the undercoat liquid are continuously discharged from the recording liquid discharge port and the undercoat liquid discharge port even during the output period of the image signal that does not form an image, and the recording liquid discharged during the output period of the image signal that does not form an image is used as the recording liquid. The image forming method according to claim 1, wherein the image is removed and collected between the discharge port and the image receptor. 4. The image forming method according to claim 1, wherein the undercoat liquid is a transparent liquid that is substantially transparent after drying. 4. The image forming method according to claim 1, wherein the undercoat liquid is an achromatic liquid that becomes substantially achromatic after drying. The recording liquid in which the mixing ratio of the image forming liquid for finally forming an image and the transparent liquid substantially transparent after drying is changed based on the image signal is discharged from the recording liquid discharge port, and this recording liquid An image forming apparatus that forms an image by shifting to an image receptor that moves relative to a discharge port,
An undercoat liquid discharge port for uniformly applying the undercoat liquid to the image receptor provided in the recording head and forming a bead of the undercoat liquid at a position where the undercoat liquid meets the image receptor;
A plurality of leads on the image receptor at the downstream side of the continuously said bead recording liquid discharged in the direction eclipse set for each pixel in the recording head substantially perpendicular to the relative movement direction of said image receptor as co beauty continuous flow A recording liquid discharge port ;
A discharge amount control means for controlling the supply amount of the image forming liquid and the transparent liquid supplied to each recording liquid discharge port;
A control unit for determining the mixing ratio of the recording liquid ejected from each recording liquid ejection port based on the image signal and controlling the ejection amount control means;
An image forming apparatus, wherein the streamline of the undercoat liquid is allowed to be disturbed upstream in the bead and the streamline of the recording liquid is prevented from being disturbed downstream of the bead. 14. The image forming apparatus according to claim 13, wherein one recording liquid discharge port is provided for each pixel of the image arranged in the width direction of the image receptor. The image forming apparatus according to claim 13, wherein a plurality of recording liquid discharge ports are formed in the moving direction of the image receptor corresponding to each pixel. 16. The image forming apparatus according to claim 14, wherein the recording liquid discharge ports for adjacent pixels are offset from each other in the transfer direction of the image receptor. A recording liquid discharge port corresponding to each pixel is connected to the recording head in the width direction of the image receptor, and the coating liquid discharged from each recording liquid discharge port is integrated in the width direction of the image receptor and discharged in a band shape. The image forming apparatus according to claim 13, wherein a slit-like recording liquid discharge port is formed. 18. The image forming apparatus according to claim 13, wherein the undercoat liquid discharge port is formed in a slit shape for discharging the undercoat liquid in a wide band shape in the width direction of the image receptor. The undercoat liquid discharge port and the recording liquid discharge port are sequentially opened on the upper surface of the recording head in the relative movement direction of the image receptor, and the image receptor is transferred with its lower surface facing the upper surface of the recording head. The image forming apparatus according to any one of 13 to 18. The undercoat liquid discharge port and the recording liquid discharge port are sequentially opened in the relative movement direction of the image receptor on the lower surface of the recording head, and the image receptor is transferred with its upper surface facing the lower surface of the recording head. The image forming apparatus according to any one of 13 to 18. The recording head is inclined such that the upper surface is lowered toward the image receiver, the lower edge of the inclined surface is horizontal in the width direction , and the lower edge moves relative to the lower edge. in proximity to the body facing undercoating liquid discharge port and the recording liquid discharge port is opened in order from the lower edge side on the inclined surface, discharging recording liquid ejected from the recording liquid discharge ports from the undercoat liquid discharge port The image forming apparatus according to any one of claims 13 to 18, wherein the image forming apparatus is guided to the image receptor by flowing down on the inclined surface in a state of being laminated on the applied undercoat liquid. The image forming apparatus according to any one of claims 13 to 21, further comprising a coating liquid recovery means for removing and recovering at least the recording liquid between the recording head and the image receiving surface. The image forming apparatus according to any one of claims 13 to 22, wherein the image receptor is a sheet-like final image receptor. The image receptor is formed of an intermediate image receptor and a final image receptor, and the recording liquid and the undercoat liquid supplied from the recording head are transferred to the final image receptor through the intermediate image receptor. The image forming apparatus according to any one of 22. Oite in the image forming apparatus according to claim 13, the discharge amount control means image forming apparatus which is formed by the discharge amount control valve provided in a passage leading to the coating solution discharge ports from the supply passage of the coating solution. Oite in the image forming apparatus according to claim 13, the discharge amount control means image forming device formed by a pump for changing the supply amount of the coating solution.

Images