JP3769424B2 - Image forming method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention generates an image recording liquid having a predetermined concentration and / or a predetermined color by changing a mixing ratio of a plurality of recording liquids based on an image signal, and uses the image recording liquid as a continuous flow on an image receptor. The present invention relates to an image forming method for guiding and forming an image, and an apparatus.
[0002]
[Prior art]
In US Pat. No. 4,109,282 (hereinafter referred to as Prior Art Document 1), 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. Disclosed is a printing apparatus in which the flow path of each ink is opened and closed by displacing the valve, and the total amount of the two liquids is kept constant, and these 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.
[0003]
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.
[0004]
Japanese Patent Laid-Open No. 63-291663 (hereinafter referred to as Prior Art Document 2) 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 thickness over the entire coating width, and a coating solution having a temporal concentration gradient with respect to the web running direction can be continuously applied with a uniform thickness in the width direction. It is a thing.
[0005]
[Problems of the prior art]
According to the method disclosed in Prior Art Document 1, the ink ejected from the nozzles is applied directly onto the paper, so if there is paper thickness or paper irregularities, the image will be faithful 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.
[0006]
According to the method disclosed in Prior Art Document 2, 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.
[0007]
Accordingly, the applicant causes a plurality of coating liquids to be discharged as a continuous flow from a plurality of coating liquid discharge ports while changing their mixing ratio based on the image signal, and the image recording liquid in the continuous flow is supplied to the image receptor. An image forming method (continuous application method) for continuous application was proposed (Japanese Patent Application No. 10-374661). Further, when the image recording liquid is continuously applied to the image receptor, the streamline of the image recording liquid is disturbed in the bead formed on the upstream side of the application portion, and the image quality is deteriorated. In order to prevent this disturbance of streamlines, the applicant has also proposed applying a transparent undercoat liquid between the image recording liquid and the image receptor (Japanese Patent Application No. 10-374663).
[0008]
  However, in these continuous coating methods, the image forming arearearEdges (edges in the direction of movement of the image receptor)in frontThe image recording liquid becomes thicker at the edge (also the edge opposite to the moving direction) compared to the center of the image forming area,rearMarginal side orin frontIt diffuses to the edge and thins. Further, the position of the image recording liquid may change. For this reason, especially in the image forming arearearNear the edgein frontIt has been found that there is a problem that the thickness of the image recording liquid is disturbed in the vicinity of the edge and the desired image quality and density cannot be obtained.
[0009]
OBJECT OF THE INVENTION
The present invention has been made in view of such circumstances. In the continuous coating method, the thickness of the image recording liquid and the position thereof are prevented from changing in the vicinity of the leading edge of the image forming region, and stable and high quality is achieved. It is a first object to provide an image forming method capable of forming a clear image. It is a second object of the present invention to provide an image forming method capable of preventing a change in the thickness or position of the image recording liquid in the vicinity of the trailing edge of the image forming region and forming a high-quality image stably. Objective. It is a third object of the present invention to provide an image forming apparatus that is directly used for carrying out these methods.
[0010]
[Structure of the invention]
  According to the present invention, a first object is to discharge an image recording liquid in which the mixing ratio of a plurality of recording liquids is changed based on an image signal from the image recording liquid discharge port, and to these image recording liquid discharge ports. An image forming method for forming an image by transferring a continuous flow to an image receptor that moves relative to the image receptor, wherein the image receptor includes an image forming area.Prior to image formationOn the tip sideIn the image forming areaThis is achieved by an image forming method characterized by transferring a dummy liquid that does not substantially form an image continuously.
[0011]
The dummy liquid is preferably transferred to the image receptor after waiting for the discharge from the dummy liquid discharge port to stabilize. Whether or not the discharge from the dummy liquid discharge port is stable can be determined based on the output of the bubble detection sensor provided in the vicinity of the dummy liquid discharge port. That is, when the dummy liquid contains bubbles, the discharge becomes unstable.
[0012]
This bubble detection sensor emits laser light to the surface (referred to as the discharge surface) of the dummy liquid discharged from the dummy liquid discharge port, and monitors the reflected light of this laser light from the surface of the dummy liquid (discharge surface). can do. In this case, it can be constituted by a laser light source, a scanning optical system for scanning the laser light with respect to the dummy liquid discharge surface, and a light receiving element for receiving the reflected light.
[0013]
  In order to prevent the dummy liquid from moving to the image receptor until the discharge of the dummy liquid is stabilized, the recording head is preferably separated from the image receptor. In addition to or instead of this, from the dummy liquid discharge portFinalA liquid recovery part may be provided in the middle of the transfer path of the dummy liquid reaching the image receptor, and unnecessary dummy liquid may be removed and recovered before reaching the image receptor.
[0014]
  The second purpose is to eject the image recording liquid in which the mixing ratio of the plurality of image recording liquids is changed based on the image signal from the image recording liquid ejection ports and to move relative to these image recording liquid ejection ports. An image forming method for forming an image by transferring the image receptor as a continuous flow to the image receptor, wherein the image receptor includes an image forming region.Delayed in image formationThe image forming method is characterized in that a dummy liquid that does not substantially form an image is transferred continuously to the rear end side.
[0015]
  In this case, it is preferable to end the transition to the image receptor immediately before the discharge of the dummy liquid is stopped, in other words, before the discharge becomes unstable. The transfer of the dummy liquid can be stopped by separating the recording head from the image receptor. With or instead of this, from the dummy liquid outletFinalYou may provide a liquid collection | recovery part in the middle of the transfer path | route of the dummy liquid which reaches an image receptor. The liquid recovery unit starts operation while the discharge of the dummy liquid transferred to the rear end side of the image forming unit is stable, and prevents the dummy liquid from transferring to the image receptor.
[0016]
  The dummy liquid is used in the image forming area.Prior to image formationTip side orDelayed in image formationYou may transfer also to the outer side of at least one of the width direction with a rear end side. In this case, not only image disturbance on the front end side or rear end side of the image forming area can be prevented, but also image disturbance on the edge in the width direction of the image forming area can be prevented.
[0017]
The image recording liquid transferred into the image forming area and the leading or rear end side of the image forming area, or the dummy liquid transferred to the outside in the width direction may be applied while being shifted in time. It is desirable that the image receptor is integrated in a direction perpendicular to or substantially perpendicular to the relative movement direction of the image receptor, and sequentially transitions sequentially in time as a strip-like continuous flow. It is desirable that at least one of the surface tension and the viscosity of the image recording liquid and the dummy liquid be substantially the same at least in the vicinity of the contact portion between the two so that the boundary between the two liquids is smoothly continuous. By making the temperature substantially the same when both are in contact, the boundary between the two can be made smoother and less disturbed.
[0018]
It is preferable that a large number of dummy liquid discharge ports are provided side by side in a direction orthogonal or substantially orthogonal to the relative movement direction of the image receptor, and the transition width of the dummy liquid is appropriately set according to the image formation width. In this case, the dummy liquid application amount from each dummy liquid discharge port can be changed to make the dummy liquid application thickness non-uniform in the length direction of the image forming region, that is, the relative movement direction of the image receptor. For example, the volumetric flow rate per unit transfer length of the dummy liquid should not exceed the volumetric flow rate per unit transfer length of the image recording liquid, or the transfer thickness of the dummy liquid gradually decreases toward the front or rear of the image forming area. By doing so, it is possible to further stabilize the dummy liquid transfer portion and improve the quality of the image at the leading edge and the trailing edge of the image forming region.
[0019]
If the image recording liquid discharge port and the dummy liquid discharge port can be shared (reused), it is possible to easily cope with changing the image forming width without replacing the recording head. The dummy liquid is preferably a transparent liquid (image non-forming liquid) that does not substantially contain an image forming substance. If at least one of a plurality of recording liquids constituting the image recording liquid is an image non-forming liquid that does not substantially form an image after image formation, the mixing ratio of the image non-forming liquid and the other recording liquid is The density can be adjusted by changing. The dummy liquid can be the same as at least a part of the image non-forming liquid that forms the image recording liquid. In this case, the type of liquid used can be reduced. Further, by keeping the volume flow rate of the image recording liquid ejected from the image recording liquid ejection port substantially constant, the transfer of the image recording liquid from the recording head to the image receptor is stabilized, which is suitable for improving the image quality.
[0020]
  A third object of the present invention is to discharge an image recording liquid in which the mixing ratio of a plurality of recording liquids is changed based on an image signal from the image recording liquid discharge ports, and to the image recording liquid discharge ports. An image forming apparatus for forming an image by moving as a continuous flow to a relatively moving image receptor,Orthogonal to the relative movement direction of the image receptorAn image recording liquid discharge port for discharging an image recording liquid that moves within the image forming width, and an image forming areaPrior to image formationTip side andDelayed in image formationTrailing edgeOn the sideA recording head having a dummy liquid discharge port for discharging a dummy liquid; image recording liquid discharge amount control means for controlling the discharge amount of the image recording liquid discharged from the image recording liquid discharge port; and discharging from the dummy liquid discharge port A dummy liquid discharge amount control means for controlling the discharge amount of the dummy liquid to be discharged; and determining the supply amount and supply timing of a plurality of recording liquids to be transferred to the image forming area based on the image signal with respect to the image recording liquid discharge port And controlling the image recording liquid discharge amount control means and determining the supply amount and supply timing of the dummy liquid to move outside the image forming area with respect to the dummy liquid discharge port to control the dummy liquid discharge amount control means. And an image forming apparatus characterized by comprising:
[0021]
By sequentially arranging the image recording liquid discharge port and the dummy liquid discharge port separately in the width direction of the recording head, the image recording liquid and the dummy liquid can be sequentially transferred to the image receptor while being shifted in time. . If the dummy liquid and the image recording liquid discharge port can be used interchangeably (mutually diverted), the dummy liquid can be transferred not only to the front end side or rear end side of the image forming area but also to the outside in the width direction, thereby changing the image forming width. It is possible to easily cope with this.
[0022]
When the image recording liquid discharge port and the dummy liquid discharge port are combined and the dummy liquid is transferred to the outside in the width direction of the image forming area, the image recording liquid discharge port and the dummy liquid discharge port are provided in the recording head. A slit-like liquid discharge port for discharging the image recording liquid and the dummy liquid in the width direction by integrating them in the width direction by connecting them in the width direction may be formed. In this case, the image recording liquid can be transferred to the image receptor more stably together with the dummy liquid. The recording head may be provided with a slit-like undercoat liquid discharge port for transferring the undercoat liquid. While transferring the undercoat liquid from the undercoat liquid discharge port, the image recording liquid and the dummy liquid are transferred on top of this, thereby preventing the thickness and position of the image recording liquid from being disturbed and further improving the image quality. it can.
[0023]
The image receptor may be transferred directly from the recording head to the image receptor as a sheet, but instead, the image receptor is replaced with an intermediate image receptor to which the transfer liquid discharged from the liquid discharge port is transferred. And the final image receptor to which the 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.
[0024]
When the image is transferred to the final image receptor via the intermediate image receptor as described above, it is preferable to provide a liquid recovery unit in the intermediate image receptor. This liquid recovery part can be formed by a blade that can contact and separate from the surface of the intermediate image receptor. That is, by pressing this blade against the surface of the intermediate image receptor, it is possible to remove and collect the liquid transferred to the surface of the intermediate image receptor and prevent it from being transferred to the final image receptor.
[0025]
The discharge amount control means can be formed by a discharge amount control valve provided in a passage from the liquid supply path to the 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.
[0026]
The transfer of the coating liquid from the recording head to the image receptor can be performed by various methods. For example, a slot coating method in which a liquid discharge port is opened on the upper surface, lower surface, or side surface of a recording head, and an image receptor or intermediate image receptor is moved to the surface where the liquid discharge port is opened at a constant interval to form an image. Can be used.
[0027]
In addition, 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 liquid discharged to the inclined surface flows down on the inclined surface and is guided to the image receptor. Further, a curtain coating method may be used in which the liquid supplied from the recording head flows down from the inclined surface onto the image receptor via the guide plate.
[0028]
[Action]
The controller transfers the dummy liquid prior to the image forming area, and transfers the image recording liquid continuously to the dummy liquid. When transferring the image recording liquid, the control unit determines a mixing ratio of a plurality of liquids led to each image recording liquid discharge port based on the image signal, and controls the color and density of the mixed liquid. The plurality of liquids forming the mixed liquid (recording liquid) are discharged as a continuous flow from the image recording liquid discharge port within the image forming width.
[0029]
  At this time, the dummy liquid may be simultaneously discharged from the dummy liquid discharge port outside the image forming width. In this case, the dummy liquid is transferred to the image receptor together with the image recording liquid. As a result, an image is formed on the image receptor. Here, since the image recording liquid is transferred in a state where the leading edge and / or the rear edge is sandwiched between the dummy liquids, the image recording liquid is transferred to the front and / or rear edge of the front edge.BehindThe thickness and position are stable, and a high-quality image can be formed. When the dummy liquid is transferred to the outside of the image forming width, the image quality of the image in the width direction is not disturbed, and the image quality is further improved.
[0030]
Embodiment
FIG. 1 is a view showing an embodiment of a slot coating method according to the present invention, FIG. 2 is a perspective view showing an internal structure of a recording head used therein, 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 coating liquid discharge ports, FIG. 6 is an explanatory diagram of the flow paths of the coating liquid and the dummy liquid, FIG. 7 is a schematic diagram showing the internal structure of the coating liquid, and FIG. It is sectional drawing which shows an application state.
[0031]
1 to 3, reference numeral 10 denotes a recording head. The recording head 10 has a large number of coating liquid discharge ports 12 opened on the upper surface thereof 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. The coating liquid discharge port 12 includes an image recording liquid / dummy liquid combined discharge port (hereinafter simply referred to as a combined discharge port) 12A and a dummy liquid discharge port 12B, which will be described later. .
[0032]
In FIG. 1, reference numeral 18 denotes a driving roller, which feeds the image receiver 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.
[0033]
Reference numeral 26 denotes a drive motor for the drive roller 18, and 28 denotes a control unit. The coating 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). As shown in FIG. 6, each coating liquid discharge port 12 within the image forming width is a dual-purpose discharge port 12A, from which the mixing ratio of the image forming liquid and the image non-forming liquid was controlled based on the image signal. A mixed liquid, that is, an image recording liquid is discharged, and a dummy liquid can be discharged instead of the image recording liquid. Further, the coating liquid discharge port 12 outside the image forming width is a dummy liquid discharge port 12B from which the dummy liquid is discharged.
[0034]
The non-image forming liquid is a liquid that does not substantially form an image after image formation (that is, after application of a recording liquid). For example, a liquid that becomes substantially transparent after drying, a UV curable liquid that becomes substantially transparent after curing, a liquid that becomes cured by heat or a chemical reaction, and becomes substantially transparent after being formed. The liquid that disappears. Here, this non-image forming liquid is also simply referred to as a transparent liquid. The image forming liquid is, for example, black ink, and the transparent liquid is transparent ink. By changing the mixing ratio of both, the image density can be changed in multiple steps (for example, 256 steps). The dummy liquid is a liquid that does not substantially contain an image forming substance, and is usually a transparent liquid.
[0035]
When the combined discharge port 12A discharges the image recording liquid, the mixing ratio of the image forming liquid and the transparent liquid forming the image recording liquid is controlled by the control unit 28 as follows. That is, 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 coating liquid discharge port 12 is divided into two paths 36 and 38 by a partition wall 34 (FIG. 3). These 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 the passages 36 and 38 are an image forming liquid discharge port 36A facing the coating liquid discharge port 12 and a transparent liquid discharge port 38A (FIGS. 2 and 3). The passages 36 and 38 are provided with an image forming liquid discharge amount control pump 40 and a transparent liquid discharge amount control pump 42 as application liquid discharge amount control means, 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 to the transparent liquid supply path 32 from the pump, and the configuration thereof is the same as that of the supply path of the image forming liquid.
[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]
When the dual-purpose discharge port 12A discharges the dummy liquid, the control unit 28 stops the image forming liquid discharge amount control pump 40 and the transparent liquid discharge amount control pump 42, and starts a dummy liquid discharge amount control pump 58 described below instead. Let That is, as shown in FIGS. 1, 3, and 6, a dummy liquid supply path 54 is formed in the width direction in the recording head 10, and each dual-purpose discharge port 12 </ b> A communicates with the dummy liquid supply path 54 through the dummy liquid path 56. ing. The dummy liquid supply path 54 is supplied with a dummy liquid by a pump (not shown). The dummy liquid passage 56 is provided with a dummy liquid discharge amount control pump 58 as dummy liquid discharge amount control means.
[0039]
Similarly, the undercoat liquid is guided to the undercoat liquid supply path 62 through the undercoat liquid supply port 60 (FIG. 2) by a pump (not shown). The undercoat liquid supply path 62 is formed long in the width direction of the recording head 10, and the slit-shaped undercoat liquid discharge port 14 communicates therewith. The undercoat liquid discharge port 14 is positioned upstream of the coating liquid discharge port 12 with respect to the feeding direction (right direction) of the image receiver 16 as shown in FIGS. Therefore, after the undercoat liquid is uniformly applied to the recording surface of the image receiver 16, a mixed liquid, that is, a recording liquid or a dummy liquid discharged from the coating liquid discharge port 12 is applied.
[0040]
The coating liquid discharge port 12 outside the image forming width is the dummy liquid discharge port 12B as described above. Although not shown in FIGS. 2 and 4, these dummy liquid discharge ports 12 </ b> B communicate with a dummy liquid supply path 54 formed in the recording head 10 as shown in FIG. 6. That is, in the recording head 10, a dummy liquid similar to the image forming liquid discharge amount control pump (Pi) 40, the transparent liquid discharge amount control pump (Pc) 42, or the dummy liquid discharge amount control pump 58 provided in the dual-purpose discharge port 12A. A supply amount control pump (Ps) 58A is formed, and the dummy liquid is sent to the dummy liquid discharge port 12B by this pump 58A.
[0041]
In FIG. 5, a plurality of dummy liquid discharge ports 12B are provided on both outer sides of the image forming width, but these are controlled so as to have the same discharge amount by the same dummy liquid supply amount control pump 58A. Accordingly, in FIG. 6, one dummy liquid discharge port 12B and one pump 58A are shown on both outer sides of the image forming width, but actually, a plurality of these may be provided as shown in FIG. 5, or as shown in FIG. One discharge port 12B and one pump 58A may be used.
[0042]
The image forming liquid discharge amount control pump 40, the transparent liquid supply amount control pump 42, and the dummy liquid supply amount control pumps 58 and 58A can have the same structure. For example, a diaphragm pump driven by a piezo element is suitable. These pumps 40, 42, 58, 58A and the passages 30, 32, 56, etc. for accommodating these control pumps 40, 42, 58, 58A are micromachines that apply techniques used in the manufacturing process of semiconductor elements and the like. The manufacturing method can be used. In FIG. 2, the coating liquid discharge ports 12 are drawn with a large interval, but are actually provided with a very small pixel interval.
[0043]
In order to narrow the application interval between the application liquid discharge ports 12, the adjacent application liquid discharge ports 12 may be displaced in the feed direction of the image receptor 16 as shown in FIG. 5A alternately shifts the adjacent coating liquid discharge ports in the reverse direction, and FIG. 5B shows an appropriate number (for example, four) of the coating liquid (recording liquid) discharge ports 12 in a certain direction. They are arranged so as to be displaced in order. In these FIG. 5, the image receptor 16 is fed to the right. When the coating liquid discharge ports 12 are displaced as described above, the control unit 28 changes the operation timing of the pumps 40 and 42 and the dummy liquid pumps 58 and 58A for different pixels in accordance with the displacement amount. Of course there is a need.
[0044]
According to this embodiment, prior to forming an image in the image forming area, the control unit 28 applies the dummy liquid to the leading end side of the image forming area. That is, the dummy liquid is discharged from the dual-purpose discharge port 12A and the dummy liquid discharge port 12B. The dummy liquid may be applied to the same width as the width of the image forming region, or may be applied to a width slightly wider than this width. Moreover, you may apply | coat over the full width.
[0045]
When the image forming area comes to the position of the coating liquid discharge port 12, or the front end of the image forming area is the time delay until the image forming liquid and the transparent liquid discharged by the pumps 40 and 42 reach the image receptor 16. When it comes in front of the discharge port 12, the discharge of the dummy liquid is stopped and the discharge of the image recording liquid is started. That is, the control unit 28 determines the operation timing and the discharge amount of the pumps 40 and 42 so as to obtain a mixing ratio corresponding to the density of each pixel based on the image signal, and controls the pumps 40, 42, and 58A. As a result, a predetermined amount of image forming liquid and transparent liquid corresponding to each pixel density are discharged from the dual-purpose discharge port 12A within the image forming width. A predetermined amount of dummy liquid is discharged from the dummy liquid discharge port 12B and applied to both sides of the image forming area in the width direction.
[0046]
When the application of the image recording liquid to the image forming area is completed, the control unit 28 continuously operates the dummy liquid discharge amount control pumps 58 and 58A. As a result, the dummy liquid is continuously applied to the rear end side of the image forming area. 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.
[0047]
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. On top of that, the dummy liquid discharged from the coating liquid discharge port 12 is applied to the front end side and the rear end side of the image forming region within the same width as the image forming width or within a wider width. In addition, an image recording liquid and a dummy liquid having a predetermined density are applied to both sides of the image forming area and its width direction, and as a result, an image whose density changes in a single color is formed on the image receiver 16.
[0048]
The dummy liquid applied to the front end side and the rear end side of the image forming area prevents the image recording liquid from becoming thicker at the front edge and the rear edge, or from being diffused forward and rearward and thinner. The dummy liquid supplied along both edges of the image recording liquid prevents the edge of the image recording liquid from becoming thick or diffusing outward in the width direction.
[0049]
Accordingly, it is desirable that the discharge volume flow rate per unit application width of the dummy liquid does not exceed the discharge volume flow rate per unit transfer width of the image recording liquid, and it is more desirable that both are set to substantially the same flow rate. Further, since the dummy liquid is preferably one that does not disturb or affect the flow of the image recording liquid, it is more desirable that the surface tension, viscosity, and temperature are substantially the same as the image recording liquid.
[0050]
The distance between the recording head 10 and the image receptor 16 is determined by the balance between the application liquid discharge port 12 and the undercoat liquid discharge port 14 and the discharge pressure of the undercoat liquid and the tension of the image receiver 16. Within this interval, a liquid pool, that is, a bead B is formed by the image recording liquid L formed of the image forming liquid I and the transparent liquid C, the dummy liquid S, and the undercoat liquid U. The image recording liquid L in this bead B is neatly transferred to the image receiver 16 without being disturbed, so that it is necessary to form an undisturbed image.
[0051]
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 C are supplied over the undercoat liquid U which has been rectified by U-turning upstream in the bead B, the image forming liquid I is a transparent liquid. It flows without disturbance along with C, and a good image can be formed.
[0052]
In this embodiment, as shown in FIG. 3, the coating 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 flow line of the coating liquid is not particularly disturbed and smoothly flows on the undercoat liquid. Further, since the transparent liquid discharge port 38A (FIGS. 2 and 3) is located downstream of the image forming liquid discharge port 36A, the transparent liquid C is interposed between the image forming liquid I and the upper surface of the recording head 10. Become. For this reason, even if the transparent liquid C 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.
[0053]
Since the dummy liquid S is continuously supplied to the front end side and the rear end side of the image recording liquid L, the boundary between the image recording liquid L and the dummy liquid S is integrated as shown in FIG. Superimposed on U. In addition, the dummy liquid is integrated on both edges of the image recording liquid L and is superimposed on the undercoat liquid U.
[0054]
The application length and width of the undercoat liquid U are the same as or larger than the total area of the image forming area and the front and rear end sides and the dummy liquid application areas on both sides thereof. For this reason, the image recording liquid L is applied in a state in which the front and rear edges and both edges are surrounded by the dummy liquid S, and the front, rear and both edges of the image recording liquid L are prevented from being disturbed.
[0055]
FIG. 8 shows the state of application in cross section in the moving direction of the image receptor 16. FIG. 8A shows the case where the dummy liquid S is not applied. As is apparent from this figure, the image recording liquid L rises due to the surface tension at the front and rear edges of the image forming area, and the image is disturbed. Yes. 8B and 8C show the case where the dummy liquid S is applied. In (B), since the image recording liquid L and the dummy liquid S are continuous, the edge of the image recording liquid L is not disturbed, and the edge of the dummy liquid S rises due to surface tension and is disturbed. However, if the dummy liquid S is transparent, the disturbance does not affect the image quality at all. (C) shows a case where the surface tension of the image recording liquid L and the dummy liquid S is small. In this case, the application thickness of the dummy liquid S changes so as to become gradually thinner toward the outside, but the application thickness of the image recording liquid L is kept constant over the entire image forming area. For this reason, the image quality does not deteriorate.
[0056]
In this embodiment, since one image forming liquid and one transparent liquid are supplied to each coating 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 coating liquid discharge port.
[0057]
The undercoat liquid, the transparent liquid, the dummy liquid, or the image forming liquid preferably contains a discoloration preventing agent for preventing deterioration of the recording liquid due to ultraviolet rays or oxidation. 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.
[0058]
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 absorbent 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 (27) -page, Japanese Patent Application Nos. 62-234103, 62-31096, Japanese Patent Application No. 62-230596, and the like.
[0059]
Examples of useful anti-fading agents are described in JP-A-62-215272, pages (125) to (137). 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.
[0060]
[Other Embodiments]
FIG. 9 is a conceptual diagram of another embodiment, and FIG. 10 is a diagram showing the operation timing. This embodiment is of the slot coating type similar to that shown in FIGS. 1 to 6, except that the recording head 10A forms an image on the final image receptor 16B via the intermediate image receptor 16A.
[0061]
  The intermediate image receiver 16A has a cylindrical shape, and the recording head 10A supplies the recording liquid L, the dummy liquid S, and the undercoat liquid U to the right edge of the intermediate image receiver 16A. Here, since the recording head 10A is configured in the same manner as that described with reference to FIGS. The recording head 10A is held by a guide post 100 so as to be able to approach and separate from the intermediate receiver 16A. A pair of left and right auxiliary rollers 102 (only one is shown) are attached to the left and right sides of the recording head 10A. These auxiliary rollers102The recording head 10A is an intermediate image receptor16AThe recording head by rolling contact with both ends of the right edge of the intermediate image receiver 16A.10AAnd the intermediate image receptor 16A are kept constant.
[0062]
The image recording liquid L and the dummy liquid discharged from the recording head 10A are placed on the intermediate image receiver 16A and are conveyed upward by the rotation of the intermediate image receiver 16A in the counterclockwise direction. At the left edge of the intermediate image receptor 16A, a final image receptor 16B such as a recording sheet is pressed by the pressure roller 104 and travels at the same speed. For this reason, the coating liquid and the undercoat liquid on the intermediate image receptor 16A are transferred to the final image receptor 16B. The final image receptor 16B is sent downward at a constant speed in FIG. 9 by the guide roller 106 and the guide belt 108, and the coating 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.
[0063]
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 make the coating liquid (image recording liquid L, dummy liquid S) and the undercoat liquid U adhere smoothly. Reference numerals 120 and 122 denote a heater and a drying air blowing duct for pre-drying the coating liquid and the undercoat liquid supplied by the recording head 10A.
[0064]
Reference numeral 124 denotes a liquid recovery blade that serves as a liquid recovery unit. The blade 124 peels off and collects liquid that is not necessary for image formation from the intermediate image receiver 16A. The coating state can be stabilized by constantly discharging the coating liquid and the undercoat liquid from the recording head 10A. Therefore, the liquid is always supplied, while unnecessary liquid is removed by the blade 124, thereby forming an image. Can be stabilized.
[0065]
However, in this embodiment, the application is started after the discharge of the dummy liquid from the recording head 10A is stabilized. For this reason, the amount of liquid removed by the blade 124 is reduced, and the amount of liquid consumption can be suppressed. That is, the recording head 10A is provided with a bubble detection sensor (not shown) at the dummy liquid discharge port, and when this sensor stops detecting bubbles for a certain period of time, it is determined that the discharge of the dummy liquid is stable. is there.
[0066]
As the bubble detection sensor, for example, a sensor that determines whether or not a bubble is contained can be used by irradiating the discharge surface of the dummy liquid with laser light and monitoring the position where the amount of laser light reflected by the discharge surface changes. A cleaning roller 126 further cleans the surface removed by the blade 124.
[0067]
Next, the operation of this embodiment will be described with reference to FIG. FIG. 10 shows the gap between the recording head 10A and the intermediate image receiver 16A, that is, the coating gap (unit: mm), and the feed speed (unit: mm / mm) of the intermediate image receiver 16A with respect to the elapsed time t on the horizontal axis. sec) and the discharge amount (unit: mL / mim / mm) of the coating liquid (dummy liquid). Here, the viscosity of the coating solution was 10 mPa · sec, and the surface tension of the coating solution was 40 mN / m.
[0068]
First, the dummy liquid discharge amount control pump 58 (see FIGS. 3 and 6) is operated in order to apply the dummy liquid to the leading end side of the image forming area. Since bubbles are normally contained in the coating liquid discharge port 12 when not in use, the discharge becomes unstable. Time t in FIG.₁~ T₂Indicates a range in which the discharge of the dummy liquid is unstable. It is desirable to prevent such a dummy liquid whose ejection is unstable from being transferred to the intermediate image receptor 16A. Therefore, the recording head 10A is separated from the intermediate image receiver 16A prior to the discharge of the dummy liquid. That is, the coating gap is about 1.0 mm. At this time, since the dummy liquid is not transferred to the intermediate image receiver 16A, the intermediate image receiver 16A is stopped.
[0069]
  Bubble detection sensor timet ₂ When the dummy liquid bubbles are no longer detected and the state continues for a predetermined time, it is determined that the discharge of the dummy liquid is stable. Then, the intermediate image receiver 16A is activated (rotated), and the recording head 10A is brought close to the intermediate image receiver 16A, so that the coating gap is about 0.2 mm. Then, the dummy liquid discharged from the coating liquid discharge port 12 (shared discharge port 12A) is applied to the intermediate image receiver 16A. The dummy liquid discharged when the discharge is unstable isCombined useSince it is attached to the ejection port 12A, the attached dummy liquid is transferred to the intermediate image receiver 16A at a time when the recording head 10A approaches the intermediate receiver 16A. This dummy liquid is removed using a blade 124.
[0070]
A stable dummy liquid is applied to the intermediate image receptor 16A, and after a predetermined time, an image recording liquid is discharged instead of discharging the dummy liquid. In FIG. 10, the time is t._ThreeIt is shown in The image recording liquid is transferred to the intermediate image receptor 16A while its density and / or color is controlled by the image signal. At the rear end of the image forming area, the coating liquid discharge port 12 discharges the dummy liquid again instead of the image recording liquid. This time is t in FIG._FourIt is shown in
[0071]
After the dummy liquid is discharged for a predetermined time from this time t4, the recording head 10A is separated from the intermediate image receiver 16A to increase the coating gap. For this reason, the dummy liquid does not move to the intermediate image receptor 16A. Thereafter, the movement (rotation) of the intermediate image receiver 16A is stopped, the discharge of the dummy liquid is also stopped, and a series of recording operations is completed.
[0072]
[Other Embodiments]
  FIG. 11 is an explanatory view of a flow path according to another embodiment. In this embodiment, a transparent liquid used for the image recording liquid is used as the dummy liquid in FIG. That is, the dummy liquidDischarge portA dummy liquid is supplied to 12B from the transparent liquid supply path 32. According to this embodiment, since the types of liquids to be used are reduced, the apparatus can be handled easily and the structure of the recording head can be simplified.
[0073]
[Other Embodiments]
FIG. 12 is a diagram showing another embodiment by the slot coating method, and FIG. 13 is an enlarged sectional view of the recording head 10B. The recording head 10B is for transferring the image recording liquid and the dummy liquid to the upper surface of the image receiver 16 that is fed horizontally.
[0074]
The image receptor 16 is fed to one side (from right to left in the figure) while being in close contact with the upper surface of the platen 70. The recording head 10B is held above the platen 70 so as to be movable up and down, and auxiliary rollers 72 (only one is shown in FIG. 12) provided at both ends in the width direction of the recording head 10B are provided at both edges of the image receiver 16. Roll contact. The auxiliary roller 72 keeps the gap between the recording head 10B and the image receiver 16 constant.
[0075]
In the recording head 10 </ b> B, 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 pump 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 pump 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.
[0076]
Further, the undercoat liquid discharge port 14 is opened upstream of the coating 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.
[0077]
Further, according to this embodiment, since the coating liquid discharge port 12 and the undercoat liquid discharge port 14 are opened on the lower surface of the recording head 10B, it is difficult for dust and dust to adhere to these discharge ports 12 and 14 and the like. For this reason, the discharge of the coating liquid becomes smooth during application, which is suitable for improving the image quality.
[0078]
【The invention's effect】
  As described above, the first aspect of the present invention provides an image forming area.Prior to image formationSince the dummy liquid that does not substantially form an image is transferred to the leading end side, the leading edge of the image recording liquid is prevented from diffusing on the image receptor, and the image is prevented from being disturbed at the leading edge of the image. Can do. Therefore, the image quality can be improved.
[0079]
If the dummy liquid is regulated so that it does not move to the image receptor until the discharge is stabilized, unnecessary dummy liquid does not adhere to the surface of the image receptor, and unevenness or unevenness of the surface does not occur outside the image forming area. The image quality is improved (claim 2). It can be detected that the discharge of the dummy liquid is unstable because the dummy liquid contains bubbles, and in this case, a bubble detection sensor may be provided. In order to prevent the dummy liquid from transferring to the image receptor when the discharge of the dummy liquid is unstable, the recording head may be separated from the image receptor. Further, a liquid recovery section may be provided in the middle of the dummy liquid transfer path, and the dummy liquid with unstable ejection may be recovered here to prevent the transfer to the image receptor.
[0080]
  According to the invention of claim 6, the image forming areaDelayed in image formationSince the dummy liquid is transferred to the rear end side, the rear end of the image recording liquid can be prevented from diffusing on the image receptor, and the image can be prevented from being disturbed at the rear edge of the image. In this case, if the transition of the dummy liquid to the image receptor is restricted while the discharge of the dummy liquid is stable, the unstable discharge of the dummy liquid will not be applied to the image receptor, which is suitable for improving the image quality ( Claim 7). In order to prevent the unstable dummy liquid from moving to the image receptor, the recording head may be separated from the image receiver while the dummy liquid is stable.
[0081]
Moreover, you may remove an unstable dummy liquid using a liquid collection | recovery part (Claim 9). The dummy liquid may be transferred to the outside in the width direction together with the front end side or the rear end side of the image forming area. In this case, the image forming liquid can be prevented from diffusing at the edge in the width direction, and the image quality is further improved.
[0082]
It is preferable that the image recording liquid and the dummy liquid sequentially and sequentially move to the image receptor in a continuous manner as a continuous flow integrated in a direction orthogonal or substantially orthogonal to the relative movement direction of the image receptor. ). As long as the image recording liquid and the dummy liquid have at least one of the surface tension and the viscosity or the temperature substantially the same in the vicinity of these contact portions, the edge of the image recording liquid is in contact with the other image recording liquid. It is close to the same state as the above, and is suitable for image quality improvement (claims 12 and 13).
[0083]
The dummy liquid application width can be changed by discharging the dummy liquid from a plurality of discharge ports arranged in a direction orthogonal or substantially orthogonal to the relative movement direction of the image receptor. Further, by changing the ejection amount in the relative movement direction of the image receptor, it is possible to more reliably prevent the image quality from being disturbed. For example, the volume flow rate per unit transition width of the dummy liquid does not exceed that of the image recording liquid (Claim 15), or the coating thickness gradually decreases as the distance from the front and rear edges of the image forming area increases. Is possible.
[0084]
The discharge port for the image recording liquid and the dummy liquid may be combined, that is, divertable. In this case, the same recording head can cope with a change in the image forming width, which is convenient. The dummy liquid is preferably a transparent liquid that does not substantially contain an image forming substance (Claim 17). When the image recording liquid is formed by mixing an image forming liquid such as ink and an image non-forming liquid, this image is used. The non-forming liquid can be used as a dummy liquid (claims 18 and 19). In this case, the physical properties of the dummy liquid and the image recording liquid are close to each other, and image disturbance is reduced. If the volume flow rate of the image recording liquid is kept constant, the dummy liquid can be controlled easily because the discharge flow rate of the dummy liquid only needs to be managed constant (claim 20).
[0085]
According to the twenty-first aspect of the present invention, an image forming apparatus that is directly used for carrying out the first or sixth aspect of the invention is obtained. If the image recording liquid discharge port and the dummy liquid discharge port are respectively arranged in the width direction of the image forming area, the dummy liquid and the image recording liquid are continuously discharged from these both discharge ports with a predetermined time difference. The image recording liquid can be reliably prevented from being disturbed by being transferred to the receiver. If a plurality of dummy liquid discharge ports are provided within the width including the image formation width and wider than the image formation width, the dummy liquid application width is wider than the image formation width, and the dummy liquid is placed outside the image formation width. It can apply | coat and can prevent disorder of the image of both edges (Claim 23).
[0086]
If at least a part of the image recording liquid discharge ports can also be used as a dummy liquid discharge port (diverted), it is possible to easily cope with a change in the image forming width, which is convenient. That is, it is possible to form images having different widths using the same recording head. If the recording head is provided so as to be able to approach and separate from the image receptor, and the discharge of the dummy liquid is unstable, the recording head is separated from the image receptor so that unnecessary dummy liquid does not move to the image receptor. This is suitable for improving the image quality. The same effect can be obtained even when the dummy liquid that is unstable or unnecessary is collected by the liquid collecting section (claim 26).
[0087]
  FinalThe image receptor may be in the form of a sheet or film such as paper, and the image recording liquid or dummy liquid may be directly transferred by the recording head here (claim 27). May be transferred to an image receptor (claims)26). In this case, by performing a pretreatment that stabilizes the surface state of the intermediate image receptor, it is less susceptible to fluctuations in the surface state of the final image receptor, and higher quality image formation becomes possible. The liquid recovery unit can be provided in the intermediate image receptor.28).
[0088]
  The discharge amount control means can be formed by a discharge amount control valve provided in a path from the coating liquid supply path to the coating liquid discharge port.29). The discharge amount control means may control the discharge amount from each discharge port by a pump provided for each coating liquid discharge port.30).
[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 an explanatory diagram of flow paths of coating liquid and dummy liquid
FIG. 7 is a block diagram showing the internal structure of the coating liquid
FIG. 8 is a cross-sectional view of a coated state
FIG. 9 is a conceptual diagram of another embodiment.
FIG. 10 is a diagram showing the operation timing of this embodiment.
FIG. 11 is an explanatory diagram of a flow path according to another embodiment.
FIG. 12 is a view showing another embodiment by a slot coating method.
FIG. 13 is an enlarged sectional view of a recording head.
[Explanation of symbols]
10, 10A, 10B Recording head
12 Coating liquid outlet
12A Image recording liquid / dummy liquid outlet
12B Dummy liquid outlet
14 Undercoat liquid outlet
16 Image receptor
28 Control unit
30 Image forming liquid supply path
32 Transparent liquid supply path
40 Image forming liquid discharge amount control pump (coating liquid discharge amount control means, Pi)
42 Transparent liquid discharge amount control pump (coating liquid discharge amount control means, Pc)
54 Dummy liquid supply path
56 Dummy liquid passage
58, 58A Dummy liquid discharge amount control pump (dummy liquid discharge amount control means, Ps)
62 Undercoat liquid supply path
124 Liquid recovery unit

Claims (30)

The image recording liquid in which the mixing ratio of the plurality of recording liquids is changed based on the image signal is discharged from the image recording liquid discharge port and continuously flows to the image receptor that moves relative to the image recording liquid discharge port. An image forming method for forming an image by transferring as
An image forming method, wherein a dummy liquid that does not substantially form an image is continuously transferred to the image receptor on the leading end side of the image forming area preceding image formation.   The image forming method according to claim 1, wherein the dummy liquid is restricted from being transferred to the image receptor until the discharge from the dummy liquid discharge port is stabilized, and is transferred to the image receptor after the discharge is stabilized.   3. The fact that the discharge of the dummy liquid from the dummy liquid discharge port is unstable is determined by a bubble detection sensor provided in the vicinity of the dummy liquid discharge port detecting that the dummy liquid contains bubbles. Image forming method.   Until the discharge of the dummy liquid from the dummy liquid discharge port becomes stable, the dummy liquid discharge port is separated from the image receptor to restrict the transfer of the dummy liquid to the image receptor. 4. The image forming method according to claim 2, wherein the liquid discharge port is brought close to the image receptor to allow the transfer of the dummy liquid to the image receptor.   A coating liquid recovery unit is provided in the middle of the dummy liquid transfer path from the dummy liquid discharge port to the image receptor. This coating liquid recovery unit is activated when the discharge of the dummy liquid is at least unstable. The image forming method according to claim 2. The image recording liquid in which the mixing ratio of the plurality of image recording liquids is changed based on the image signal is discharged from the image recording liquid discharge port and continuously to the image receptor that moves relative to these image recording liquid discharge ports. An image forming method for forming an image by transferring as a stream,
An image forming method, wherein a dummy liquid that does not substantially form an image is continuously transferred to the image receptor on the rear end side that is delayed in image formation in an image forming region.   7. The image forming method according to claim 6, wherein the dummy liquid is restricted from being transferred to the image receptor while the discharge from the dummy liquid discharge port is stable, and the transfer of the dummy liquid is terminated.   8. The image forming method according to claim 7, wherein the dummy liquid discharge port is separated from the image receptor while the discharge of the dummy liquid from the dummy liquid discharge port is stable to restrict the transfer of the dummy liquid to the image receiver.   A coating liquid recovery unit is provided in the middle of a dummy liquid transfer path from the dummy liquid discharge port to the image receptor, and the coating liquid recovery unit starts operating while the discharge of the dummy liquid is stable. The image forming method according to any one of 8. 10. The image forming method according to claim 1, wherein the dummy liquid is transferred to the outside in the width direction orthogonal to the relative movement direction of the image receptor in the image forming area.   The image recording liquid transferred to the image forming area and the dummy liquid transferred to the outside of the image forming area are respectively imaged as a continuous flow integrated in a direction orthogonal or substantially orthogonal to the relative movement direction of the image receptor. The image forming method according to claim 1, wherein the image forming method is successively and sequentially transferred to a receptor.   12. The image forming method according to claim 1, wherein at least one of the surface tension and the viscosity of the image recording liquid and the dummy liquid is substantially the same at least in the vicinity of the contact portion between them.   The image forming method according to claim 1, wherein at least the image recording liquid and the dummy liquid are at substantially the same temperature when they are in contact with each other.   The image forming method according to claim 1, wherein the dummy liquid is discharged from a plurality of dummy liquid discharge ports arranged in a direction orthogonal or substantially orthogonal to the relative movement direction of the image receptor.   15. The image forming method according to claim 1, wherein the volume flow rate per unit transfer width of the dummy liquid does not exceed the volume flow rate per unit transfer width of the image recording liquid.   The recording liquid discharge port that discharges the image recording liquid and the dummy liquid discharge port that discharges the dummy liquid can be used together. The recording liquid discharge port and the dummy liquid discharge port correspond to the image forming area and receive the image recording liquid or the dummy liquid. The image forming method according to claim 1, wherein each of the image forming methods can be discharged.   The image forming method according to claim 1, wherein the dummy liquid is a liquid that does not substantially contain an image forming substance.   18. The image forming method according to claim 1, wherein at least one of the plurality of recording liquids forming the image recording liquid is an image non-forming liquid that does not substantially form an image after image formation.   19. The image forming method according to claim 18, wherein the dummy liquid is the same as at least a part of the plurality of recording liquids forming the image recording liquid. 20. The image recording liquid discharged from each image recording liquid discharge port is changed in at least one of density and color by changing a mixing ratio of a plurality of recording liquids while keeping a volume flow rate substantially constant. Any image forming method. The image recording liquid in which the mixing ratio of the plurality of recording liquids is changed based on the image signal is discharged from the image recording liquid discharge port and continuously flows to the image receptor that moves relative to the image recording liquid discharge port. An image forming apparatus that forms an image by shifting as
An image recording liquid discharge port for discharging an image recording liquid that moves within an image forming width orthogonal to the relative movement direction of the image receptor, and a leading end side that precedes image formation and a trailing end side that is delayed in image formation in the image forming area. A recording head having a dummy liquid discharge port for discharging the dummy liquid;
Image recording liquid discharge amount control means for controlling the discharge amount of the image recording liquid discharged from the image recording liquid discharge port;
Dummy liquid discharge amount control means for controlling the discharge amount of the dummy liquid discharged from the dummy liquid discharge port;
Based on the image signal, the supply amount and supply timing of a plurality of recording liquids to be transferred to the image forming area with respect to the image recording liquid discharge port are determined, and the image recording liquid discharge amount control means is controlled. A control unit that determines the supply amount and supply timing of the dummy liquid that moves outside the image forming area and controls the dummy liquid discharge amount control means;
An image forming apparatus comprising:   The image forming apparatus according to claim 21, wherein the image recording liquid discharge port and the dummy liquid discharge port are arranged in a direction orthogonal or substantially orthogonal to the relative movement direction of the image receptor.   23. The image forming apparatus according to claim 22, wherein a plurality of dummy liquid discharge ports are provided within a width including the image forming width and wider than the image forming width.   The image forming apparatus according to any one of claims 21 to 23, wherein at least some of the image recording liquid discharge ports can also be used as dummy liquid discharge ports. The recording head is held so as to be able to approach and separate from the image receptor, and the recording head approaches the image receptor after waiting for the discharge of the dummy liquid that moves to the leading edge side preceding the image formation in the image forming area to stabilize. The image according to any one of claims 21 to 24, which is controlled by the control unit so as to be separated from the image receptor while the discharge of the dummy liquid that moves to the rear end side that is delayed in image formation in the image forming region is stable. Forming equipment. Image receptor is formed by the intermediate image receptor and the final image receptor, the coating liquid supplied from the recording head is moved to the final image receptor through the intermediate image receiving member, from the final dummy liquid discharge port 26. A liquid recovery part provided in the middle of a transfer path of the dummy liquid to the image receptor, wherein the liquid recovery part operates when the discharge of the dummy liquid is at least unstable and recovers the dummy liquid. Any image forming apparatus. 27. The image forming apparatus according to claim 26, wherein the final image receptor is in the form of a sheet. The image forming apparatus according to claim 26 , wherein the liquid recovery unit is provided in the intermediate image receiver. 22. The image forming apparatus according to claim 21, wherein the discharge amount control means is formed by a discharge amount control valve provided in a passage extending from at least one supply path of the image recording liquid and the dummy liquid to the coating liquid discharge port. 22. The image forming apparatus according to claim 21, wherein the discharge amount control means is formed by a pump that changes a supply amount of at least one of the image recording liquid and the dummy liquid.

Images