JP4715478B2 - Image recording method, image recording apparatus, and image recording system - Google Patents

Description

  The present invention relates to an image recording method, an image recording apparatus, and an image recording system, and more particularly, to an inkjet image recording method, an image recording apparatus, and an image recording system.

  2. Description of the Related Art Conventionally, an image recording apparatus using ultraviolet curable ink has been developed as an ink jet image recording apparatus that can be used for various recording media. For example, in the image recording apparatus described in Patent Document 1, an ink droplet landed on a recording medium by ejecting an ultraviolet curable ink containing a photoinitiator having a predetermined sensitivity to light such as ultraviolet rays. An image is recorded on a recording medium by irradiating the film with ultraviolet rays.

  According to such an image recording apparatus, since ink droplets are instantaneously cured by being irradiated with ultraviolet rays after landing on the recording medium, there is no need to absorb the ink in the recording medium, and not only on plain paper. It is possible to record an image on a recording medium having a low ink absorption such as plastic or metal.

  However, when ink is ejected onto a recording medium having low ink absorbability and high surface liquid repellency (see FIG. 8A), the ink droplets are repelled on the surface of the recording medium and adhere to the surface. Is weak, but the attracting force between adjacent ink droplets is strong, so that it moves from the landing position (see FIG. 8B), and repelling (a hole-like portion where no ink is present) occurs. (See FIG. 8 (c)). Furthermore, when an image is recorded using 85% or more of the ink amount required to record a solid image, there is a problem that the quality of the recorded image is remarkably deteriorated when repelling occurs.

Therefore, an ultraviolet curable ink composition that has high ink wettability when landed on a recording medium and is excellent in preventing repelling is known (see Patent Document 2). According to such an ultraviolet curable ink composition, the surface has high liquid repellency, and the ink wettability to a recording medium such as metal or glass is high, and the wettability when overcoated is also high, thereby preventing repelling. Thus, it can be suitably used for image formation.
JP 2001-310454 A JP 2003-147233 A

  In recent years, an inkjet image recording apparatus has been used for post-processing such as laminating, PP application, varnishing, and partial varnishing for the purpose of image protection, gloss imparting, information addition, etc. on recording media on which images have already been formed A technique is known that is performed by ejecting a predetermined ink. By performing such post-processing by an ink jet method, it is possible to perform post-processing on a small lot printed matter easily and inexpensively.

  However, image forming materials used in such small-lot printing often contain wax or the like that enhances liquid repellency, and is particularly smooth against images recorded using such image forming materials. However, it is difficult to cause the ink to be discharged, and repelling occurs.

  The present invention has been made in view of these points, and an object of the present invention is to provide an image recording method capable of recording a glossy image without moving ink droplets that have landed on a recording medium.

In order to solve the above problem, the invention according to claim 1 is:
Image recording method for recording an image by repeating a recording step of discharging ink toward a recording medium and irradiating the ink droplet landed on the recording medium with an active energy ray to cure the ink droplet a plurality of times In
The ink has a static contact angle of 90 to 120 degrees with respect to the recording medium,
The image recorded by performing the recording process a predetermined number of times uses 85% or more of the ink amount required to record a solid image,
In the first recording step, the ink is ejected so that ink droplets that do not form the same pixel do not contact each other after landing on the recording medium, and in the second and subsequent recording steps. the ink discharge so as to fill between the ink droplets which are cured on the recording medium, the diameter of ink droplets that have landed is discharged during the second and subsequent said recording step, the first-time the recording step The diameter is larger than the diameter of the ink droplets ejected and landed at the time .

According to the first aspect of the present invention, ink droplets that do not form the same pixel ejected for the first time do not contact the recording medium after landing, and adjacent ink droplets attract each other. Prevents movement from the landing position. Also, since the ink droplets ejected for the first time are cured by irradiating the active energy rays, the ink droplets ejected for the second and subsequent times are in contact with the cured ink. And spread evenly.
According to the first aspect of the present invention, the diameter of the ink droplets ejected from the second time is larger than the diameter of the ink droplets ejected from the first time. Can be filled.

The invention according to claim 2 is the image recording method according to claim 1,
The ink is characterized in that a static contact angle between a cured ink droplet and an uncured ink droplet is 10 to 50 degrees.

  According to the invention described in claim 2, the ink used has a static contact angle of 10 to 50 degrees between the cured ink droplet and the uncured ink droplet, and the wetness between the cured ink and the uncured ink is low. Good sex. Therefore, when the ejected ink droplets land on the recording medium, they come into contact with the already cured ink and spread over a wide range.

The invention according to claim 3 is the image recording method according to claim 1 or 2,
The resolution after landing of ink droplets discharged in the first recording step is 2 to 6 times the resolution after landing of ink droplets discharged in the second and subsequent recording steps. It is characterized by that.

  According to the third aspect of the invention, in the first recording process, the ink is ejected so as to be higher than the resolution in the second and subsequent recording processes. An ink droplet smaller than the droplet is ejected and landed.

The invention according to claim 4 is the image recording method according to any one of claims 1 to 3,
The diameter of the ink droplets ejected and landed in the second and subsequent recording steps is the average value of the distance between the centers of the ink droplets ejected and landed in the first recording step. It is 5 to 2.5 times.

  According to the fourth aspect of the present invention, the diameter of the ink droplets discharged after the second time is 1.5 to 2.5, which is an average value of the center-to-center distance between the ink droplets discharged for the first time. Therefore, the ink droplets discharged after the second time easily come into contact with the cured ink discharged for the first time after landing.

The invention according to claim 5 is the image recording method according to any one of claims 1 to 4 ,
The ink is an ultraviolet curable ink and has a surface tension of 0.02 to 0.06 N / m.

According to the invention described in claim 5 , it is possible to use an ultraviolet curable ink having a surface tension of 0.02 to 0.06 N / m and a high viscosity and poor wettability.

The invention according to claim 6 is the image recording method according to any one of claims 1 to 5 ,
The ink is a transparent ink.

According to the sixth aspect of the present invention, since transparent ink is used, it is possible to prevent the occurrence of uneven glossiness by ejecting the ink uniformly when giving glossiness to the image.

According to the seventh aspect of the present invention, the operation of ejecting ink toward the recording medium and irradiating the ink droplet landed on the recording medium with an active energy ray to cure the ink droplet is repeated a plurality of times. In an image recording apparatus for recording images,
The ink has a static contact angle of 90 to 120 degrees with respect to the recording medium,
An image recorded by performing the above operation a predetermined number of times uses 85% or more of an ink amount required to record a solid image,
In the first operation, the ink is discharged so that ink droplets that do not form the same pixel do not contact each other after landing on the recording medium, and in the second and subsequent recording steps, the ink is discharged. the ink to fill the inter-cured on the recording medium ink droplets eject the diameter of ink droplets that have landed is discharged during the second and subsequent said recording step, the first time of the recording process The diameter is larger than the diameter of the ink droplets ejected and landed .

According to the seventh aspect of the present invention, ink droplets that do not form the same pixel ejected for the first time do not contact the recording medium after landing, and adjacent ink droplets attract each other. Prevents movement from the landing position. Also, since the ink droplets ejected for the first time are cured by irradiating the active energy rays, the ink droplets ejected for the second and subsequent times are in contact with the cured ink. And spread evenly.
According to the seventh aspect of the present invention, the diameter of the ink droplets ejected from the second time is larger than the diameter of the ink droplets ejected from the first time. Can be filled.

The invention according to claim 8 provides:
A first image recording apparatus for recording an image on a recording medium;
An operation of ejecting ink droplets toward the recording medium on which an image is recorded by the first image recording apparatus and irradiating the ink droplets with active energy rays to cure the ink droplets is performed a plurality of times. A second image recording device for repeatedly recording an image;
In an image recording system comprising:
The ink used in the second image recording apparatus has a static contact angle with respect to the recording medium of 90 to 120 degrees,
The image recorded by the second image recording apparatus uses 85% or more of the ink amount required to record a solid image, and does not form the same pixel during the first operation. The ink is ejected so that the droplets do not contact the recording medium after landing, and the ink is ejected so as to fill the space between the ink droplets cured on the recording medium in the second and subsequent operations. The diameter of the ink droplet ejected and landed in the second and subsequent recording steps is larger than the diameter of the ink droplet ejected and landed in the first recording step. .

According to the eighth aspect of the present invention, when an image is recorded by the second image recording apparatus, ink droplets that do not form the same pixel ejected first time do not contact the recording medium after landing. Adjacent ink droplets are attracted to each other and are prevented from moving from the landing position. Also, since the ink droplets ejected for the first time are cured by irradiating the active energy rays, the ink droplets ejected for the second and subsequent times are in contact with the cured ink. And spread evenly.
According to the eighth aspect of the present invention, the diameter of the ink droplets ejected from the second time is larger than the diameter of the ink droplets ejected from the first time. Can be filled.

The invention according to claim 9 is the image recording system according to claim 8 ,
The first image recording apparatus is a charge copying type image recording apparatus.

According to the invention described in claim 9 , since the first image recording apparatus is a charged copying system, ink droplet repelling is likely to occur on the recording medium on which the image is recorded by the first image recording apparatus. The second image recording apparatus records an image on a recording medium on which an image is recorded while preventing the occurrence of cissing.

The invention according to claim 10 is the image recording system according to claim 8 or 9 , wherein
The toner used by the first image recording apparatus contains a wax.

According to the invention described in claim 10 , since the toner used by the first image recording apparatus contains wax, the image recorded by the first image recording apparatus is particularly easy to repel ink on the surface thereof. However, the second image recording apparatus discharges the sheets so that the surface is uniform while preventing repelling.

According to the first aspect of the present invention, the ink droplets are cured on the recording medium without moving from the landing position. Therefore, it is possible to accurately form an image by preventing ink droplets that do not form the same pixel that has landed from being collected and causing repelling or a change in the contour of the recorded image. is there. In addition, since the ink droplets discharged after the second time are in contact with the cured ink and spread evenly, it is possible to prevent repelling and smoothly eject the ink onto the recording medium to give gloss. is there.
According to the first aspect of the present invention, the space between the cured inks can be easily filled with the ink droplets discharged after the second time, so that even an image that requires a large amount of ink for recording can be easily obtained. Can be recorded. In addition, since the dot diameter of the ink droplets discharged after the second time is large, a glossy image can be recorded.

  According to the second aspect of the present invention, since the ejected ink spreads between the already cured inks, it is possible to make the surface of the recording medium uniform and smooth, and to give the image gloss. It is.

  According to the third aspect of the present invention, since the ink droplets discharged after the second time have a larger dot diameter than the ink droplets discharged for the first time, the cured ink droplets discharged after the first time It can spread easily in contact with the ink. Further, the ink droplets ejected after the second time may have a large dot diameter, and an image that requires a large amount of ink for recording can be easily recorded. Furthermore, since the dot diameter of the ink droplets discharged after the second time is large, a glossy image can be recorded.

  According to the invention described in claim 4, since the ink droplets ejected after the second time easily come into contact with the cured ink ejected the first time, the ink droplets land so as to cover a plurality of cured inks. And can spread in contact with the cured ink.

According to the fifth aspect of the present invention, the ink can be applied to ink having high viscosity and poor wettability.

According to the sixth aspect of the present invention, it is possible to give a uniform gloss to an arbitrary image.

According to the seventh aspect of the invention, the ink droplets are cured on the recording medium without moving from the landing position. Therefore, it is possible to accurately form an image by preventing ink droplets that do not form the same pixel that has landed from being collected and causing repelling or a change in the contour of the recorded image. is there. In addition, since the ink droplets discharged after the second time are in contact with the cured ink and spread evenly, it is possible to prevent repelling and smoothly eject the ink onto the recording medium to give gloss. is there.
According to the seventh aspect of the present invention, the space between the cured inks can be easily filled with the ink droplets ejected from the second time onward, so that even an image that requires a large amount of ink to be recorded is easy. Can be recorded. In addition, since the dot diameter of the ink droplets discharged after the second time is large, a glossy image can be recorded.

According to the eighth aspect of the invention, when an image is recorded by the second image recording device, the ink droplet is cured on the recording medium without moving from the landing position. Therefore, it is possible to accurately form an image by preventing ink droplets that do not form the same pixel that has landed from being collected and causing repelling or a change in the contour of the recorded image. is there. In addition, since the ink droplets discharged after the second time are in contact with the cured ink and spread evenly, it is possible to prevent repelling and smoothly eject the ink onto the recording medium to give gloss. is there.
According to the eighth aspect of the present invention, the space between the cured inks can be easily filled with the ink droplets ejected from the second time onward, so that even an image that requires a large amount of ink to be recorded is easy. Can be recorded. In addition, since the dot diameter of the ink droplets discharged after the second time is large, a glossy image can be recorded.

According to the ninth aspect of the invention, the second image recording apparatus is glossy while preventing the ink droplets from moving from the landing position onto the upper surface of the recording medium on which the image is recorded by the charging copying method. It is possible to record an image.

According to the invention described in claim 10 , since the ink is ejected accurately and evenly onto the image recorded by the first image recording apparatus using the toner containing wax, the recorded image is protected and the gloss is imparted. It is possible to give special information.

  Hereinafter, an embodiment of an image recording apparatus according to the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

  As shown in FIG. 1, the image recording apparatus 1 according to the present embodiment includes a cylindrical drum 2 that is rotatable while holding a recording medium. The drum 2 is connected to a rotation mechanism 3 that rotates the drum 2 at a predetermined rotation speed during image recording. As shown in FIG. 2, the drum 2 is provided with a holding mechanism 4 that holds the recording medium in a state of being wound around the peripheral surface. The holding mechanism 4 is provided on each of the inner surfaces of the drum 2 and corresponding to both ends in the recording medium conveyance direction. The holding mechanism 4 is not particularly limited, and the recording medium may be attracted by generating static electricity on the peripheral surface of the drum 2.

  A guide roller 5 that sequentially guides the recording medium to the peripheral surface of the drum 2 is rotatably provided at a position facing the drum 2. A discharge tray (not shown) for discharging the recording medium released from the holding mechanism 4 is provided below the drum 2.

  Two sets of guide rails (not shown) extending in parallel with the rotation axis direction of the drum 2 are provided above the peripheral surface of the drum 2. A head unit 6 including a recording head 7 to be described later is supported on the guide rail on the upstream side in the transport direction so as to be able to reciprocate in a direction along the guide rail (hereinafter, “sub-scanning direction”). A maintenance unit 6 a that performs maintenance of the recording head 7 and the like is provided on the side of the drum 2 and at a position facing the lower surface of the head unit 6.

  In the head unit 6, a plurality of recording heads 7, which record an image by ejecting ink toward the recording medium, are arranged in a staggered manner. As shown in FIG. 3, the recording head 7 ejects process color inks (yellow (Y), magenta (M), cyan (C), black (K)) as actual image inks. A non-process color ink (white (W), clear) is ejected as background ink. The recording head 7 is formed in a rectangular parallelepiped shape, and is arranged such that its longitudinal direction is along the sub-scanning direction. A plurality of nozzles (not shown) for discharging ink droplets are disposed on the surface of the recording head 7 facing the recording medium. The arrangement pattern of the recording heads 7 in the head unit 6 is not particularly limited and can be changed as appropriate.

  An ultraviolet irradiation device 8 that irradiates ultraviolet rays toward a recording medium conveyed below the guide rail on the downstream side in the conveyance direction is supported so as to be reciprocally movable in the sub-scanning direction. The ultraviolet irradiation device 8 is provided with a light source 9 for irradiating ultraviolet rays for curing ink droplets. In the present embodiment, the light source 9 irradiates ultraviolet rays, but those that irradiate active energy rays such as electron beams, X-rays, visible light, and infrared light can be applied according to the ink used.

Here, “ink” used in the present embodiment will be described.
The ink used in the present embodiment has a static contact angle of 90 to 120 degrees with respect to the recording medium. Moreover, the thing whose static contact angle with the ink droplet after hardening is 10 to 50 degree | times is preferable. Here, the static contact angle indicates the wettability of ink droplets. When the static contact angle is 0 degree, the ink wettability is high, and the ink droplets adhere to the object without being repelled. On the other hand, when the static contact angle is 180 degrees, the ink wettability is low, and the ink droplet is bounced off the object and does not adhere at all. The static contact angle can be easily measured using a known contact angle measuring device (for example, automatic contact angle measuring device CA-V type: manufactured by Kyowa Interface Chemical Co., Ltd.).

  In addition, the ink used in the present embodiment is cured by being irradiated with an active energy ray. Specifically, it is an ultraviolet curable ink that is cured by irradiation with ultraviolet rays as active energy rays, and contains at least a polymerizable compound (including a known polymerizable compound) and a photoinitiator as main components. Is. Such ultraviolet curable inks are roughly classified into radical polymerization inks containing radical polymerizable compounds as polymerizable compounds and cationic polymerization inks containing cationic polymerizable compounds. Each ink can be applied as an ink used in the embodiment, and a hybrid ink in which a radical polymerization ink and a cation polymerization ink are combined may be applied as an ink used in the present embodiment. However, it is particularly preferable to use a cationic polymerization ink because a cationic polymerization ink that has little or no inhibitory action on the polymerization reaction due to oxygen is superior in functionality and versatility.

  In the present embodiment, ultraviolet curable ink having a surface tension of 0.02 to 0.06 N / m may be used. Since such ink has high viscosity and poor wettability, when recording an image close to a solid image by the conventional method, there are problems that repelling is likely to occur and the ink surface is not easily smoothed. According to the image recording method of the invention, it is possible to impart glossiness by smoothing the ink surface while preventing the occurrence of cissing.

  Furthermore, the ink used in the present embodiment may be a transparent ink without adding a coloring material to the main component. In particular, it is preferable to use a special ink in which various additives are added to the ink ejected by the recording head 7 because the special ink is ejected onto a previously recorded image and post-processing can be performed. Examples of post-processing include image protection for ejecting highly durable ink onto a recorded image, glossing for ejecting glossy ink onto a recording medium, and special ink that can be read by a special method on the recording medium. For example, information is given for ejection.

Next, the “recording medium” used in the present embodiment will be described.
As for the recording medium used in the present embodiment, various papers such as plain paper, recycled paper, and glossy paper that are applied to ordinary inkjet printers, various fabrics, various non-woven fabrics, resins, metals, glass, and the like are used. Is applicable. In particular, from the viewpoint of wettability with ink droplets, a non-absorbing recording medium that hardly absorbs the landed ink droplets is preferable. For example, water-resistant coated paper and various non-absorbable plastic films used for so-called soft packaging can be used. Moreover, there is no restriction | limiting in particular as a form of a recording medium, For example, a roll shape, a cut sheet shape, and a plate-shaped thing can be used according to the holding mechanism 4. FIG. In this embodiment, since the holding mechanism 4 that holds both ends in the conveyance direction of the recording medium is used, a cut sheet-like one is used.

Next, the control configuration of the image recording apparatus 1 according to the present embodiment will be described.
As shown in FIG. 4, the image recording apparatus 1 is electrically connected to a recording head 7, an ultraviolet irradiation device 8, a sub-scanning mechanism 10, a drum 2 rotating mechanism 3, a recording medium transport mechanism 11, a holding mechanism 4, and the like. A control unit 12 that is connected and controls them is provided. The control unit 12 includes, for example, a CPU, a ROM, and a RAM (all not shown), and develops a processing program recorded in the ROM on the RAM and executes the processing program by the CPU.

  During image recording, the control unit 12 controls the rotation mechanism 3 so that the drum 2 rotates at a predetermined rotation speed, and moves the recording medium in the conveyance direction by the conveyance mechanism 11 in accordance with the rotation speed of the drum 2. It is controlled so that it is conveyed sequentially. Further, the control unit 12 controls the holding mechanism 4 so that the recording medium guided by the guide roller 5 is held by the drum 2 in accordance with the conveyance of the recording medium. Further, the controller 12 releases the holding of the recording medium by the holding mechanism 4 when the image recording of the recording medium held on the drum 2 is completed.

  When the image is recorded, the control unit 12 controls the sub-scanning mechanism 10 so that the head unit 6 and the ultraviolet irradiation device 8 move in the sub-scanning direction in accordance with the rotation speed of the drum 2. At that time, the control unit 12 performs control so that ink is ejected by the recording head 7 in accordance with the movement of the head unit 6 in the sub scanning direction, and the light source 9 is turned on while the ultraviolet irradiation device 8 moves in the sub scanning direction. You are in control.

  Here, in the present embodiment, the control unit 12 rotates the drum 2 a plurality of times, and performs a recording process for performing the ink ejection by the recording head 7 and the ultraviolet irradiation by the ultraviolet irradiation device 8 in order several times. The image is recorded repeatedly. Then, when recording an image close to a solid image, the control unit 12 performs recording so that ink droplets that do not form the same pixel that has landed on the recording medium do not come into contact with each other when the first recording process is performed. Control is performed so that ink is ejected by the head 7. Specifically, in the first recording step, the control unit 12 uses 1 to 25% of the ink amount used for recording the solid image, and ink droplets that do not form the same pixel after landing on the recording medium. It controls so that it may discharge so that each may leave predetermined intervals (refer Fig.6 (a)). Here, an image close to a solid image means an image that requires an ink amount of 85% or more, assuming that the ink amount used for recording a solid image is 100%.

  Next, an image recording method as an operation of the image recording apparatus 1 according to the present embodiment will be described. Here, it is assumed that the image recording apparatus 1 records an image close to a solid image.

  First, when predetermined image information is sent to the image recording apparatus 1, the rotation mechanism 3 starts rotating the drum 2 and accelerates it until a predetermined rotation speed is reached. When the rotational speed of the drum 2 reaches a predetermined value, the transport mechanism 11 transports the recording medium and guides the transported recording medium to the peripheral surface of the drum 2 on which the guide roller 5 is rotating. Then, the holding mechanism 4 first holds the end of the recording medium in the transport direction, and winds the recording medium around the circumferential surface of the drum 2 as the drum 2 rotates. Further, the holding mechanism 4 clamps the end on the rear end side in the conveyance direction of the recording medium, and the control unit 12 starts image recording on the recording medium.

  First, the control unit 12 causes the first recording process to be performed during one rotation of the drum 2 after starting image recording. Specifically, the head unit 6 is moved in the sub scanning direction along the guide rail by the sub scanning mechanism 10. Along with this, the recording head 7 also moves in the sub-scanning direction, and discharges predetermined ink that forms an image so that ink droplets that do not form the same pixel landed on the recording medium do not come into contact with each other. Then, when the ink droplets that have landed on the recording medium face the ultraviolet irradiation device 8 as the drum 2 rotates, the ink droplets are irradiated with ultraviolet rays from the light source 9 and are cured without being in contact with each other.

  Here, when performing the first recording step, it is preferable to eject ink from the recording head 7 so that the resolution after landing of the ink droplets is 2 to 6 times that in the second and subsequent recording steps. . By increasing the resolution after landing of the first ink droplet that is ejected, the ink droplet becomes smaller, so that ink droplets that do not form the same pixel do not contact each other after landing and are independent. It is possible to maintain the state efficiently.

  Subsequently, the control unit 12 causes the second recording process to be performed while the drum 2 further rotates one more time. Specifically, the recording head 7 ejects predetermined ink as the head unit 6 moves in the sub-scanning direction. The cured ink that has already been ejected for the first time exists in the recording medium in an independent state (see FIG. 5A), and the ink droplets ejected in the second recording process are separated from the recording medium. The ink is landed so as to come into contact with the ink after curing (see FIG. 5B). In FIG. 5, uncured ink is hatched. When the ink droplets ejected a second time come into contact with the ink after curing on the recording medium, the ink droplets adhere to the ink after the curing and spread. When ink droplets spread, adjacent ink droplets come into contact with each other, and the ink becomes uniform on the recording medium. Thereafter, as the drum 2 rotates, the ink is conveyed below the ultraviolet irradiation device 8 and cured.

  Here, when the static contact angle between the uncured ink droplet and the cured ink droplet is 10 to 50 degrees, the wettability is high. Can spread easily in contact with ink.

  In addition, when performing the second and subsequent recording steps, it is preferable that the ink is ejected so as to be larger than the dot diameter of the ink droplets ejected in the first recording step. Further, it is preferable to eject the ink droplets at 1.5 to 2.5 times the average value of the center-to-center distance between the ink droplets ejected in the first recording step. By performing the second and subsequent ink ejections in this way, the ink ejected the first time can be easily contacted and spread after landing to fill the space between the hardened inks, so that an image close to a solid image can be recorded by a small number of recording steps. Can be recorded. In addition, since the second and subsequent ink ejections can be performed with a lower resolution than the first ink ejection, the load on the recording head 7 can be reduced.

  As shown in FIG. 6, the recording of an image close to a solid image is completed by repeating such a recording process a predetermined number of times. When the image recording is finished, the holding mechanism 4 releases the holding of the recording medium, and the recording medium is discharged to a discharge tray provided below the drum 2.

As described above, according to the image recording apparatus 1 of the present embodiment, in the first recording process, the ink droplets are cured on the recording medium without moving from the landing position. Therefore, it is possible to accurately form an image by preventing ink droplets that do not form the same pixel that has landed from being collected and causing repelling or a change in the contour of the recorded image. is there. Here, as in the present embodiment, in the case of the ink jet image recording apparatus 1, in order to increase the amount of ink for forming one pixel, a plurality of ink droplets can be continuously ejected at the same position. is there. Then, it is preferable that the ink droplets forming the same pixel come into contact with each other and spread smoothly, but if the ink droplets that do not form the same pixel come into contact with each other, the outline of the image that is moved and recorded from the landing position is changed. There is a detrimental effect that the dye component contained in the ink droplet changes or is mixed. However, according to the present invention, since ink droplets that do not form the same pixel do not contact each other, it is possible to prevent such an adverse effect.
In addition, since the ink droplets discharged after the second time are in contact with the cured ink and spread evenly, it is possible to prevent repelling and smoothly eject the ink onto the recording medium to give gloss. is there.

  In the present embodiment, the image recording on the recording medium is performed by one image recording apparatus 1. However, as shown in FIG. 7, the first image recording apparatus for recording an image on the recording medium, The present invention is also applicable to an image recording system including a second image recording apparatus that performs post-processing on a recording medium on which an image is recorded. In that case, the second image recording apparatus performs post-processing by the image recording method according to the present invention on the recording medium on which the image is recorded by the first image recording apparatus. According to such an image recording system, the second image recording apparatus ejects post-processing ink on the image recorded using the image forming material by the first image recording apparatus to give gloss. Alternatively, it is possible to add information by ejecting special ink to an arbitrary location. In this case, the toner as the image forming material used by the first image recording apparatus may contain wax. When the toner contains wax, there is a problem that the ink adheres to the surface of the recorded image and is easily repelled. However, according to the present invention, the ink ejected for the first time by the second image recording apparatus is cured without deviation from the landing position even on the image recorded using the toner containing the wax. Ink can be uniformly ejected onto the recording medium. The present invention is also applicable to the case where the first image recording apparatus is a charged copying system or an electrophotographic system.

  In this embodiment, the head unit 6 moves on the guide rail, and the position in the conveyance direction (main scanning direction) of the recording medium orthogonal to the sub-scanning direction is fixed. May be moved in the main scanning direction.

1 is a perspective view showing an image recording apparatus according to the present invention. 1 is a side view showing an image recording apparatus according to the present invention. FIG. 3 is a plan view showing the arrangement of recording heads according to the present invention. It is a block diagram which shows the control structure of the image recording apparatus which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram illustrating an image recording method according to the present invention, where (a) is a side view of a recording medium after a first recording step, and (b) is a side view of the recording medium after a second and subsequent recording steps. It is. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram illustrating an image recording method according to the present invention, where (a) is a plan view of a recording medium after a first recording step, and (b) is a plan view of a recording medium after a second and subsequent recording steps. It is. It is explanatory drawing which shows the image recording system which concerns on this invention. FIG. 9 is an explanatory view showing a conventional image recording method, (a) is a side view of a recording medium after ink droplet landing, and (b) is a side view showing a state in which the ink droplet moves on the recording medium. FIG. 4C is a side view showing a state where ink droplets move and repelling occurs or the image contour is deformed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image recording apparatus 2 Drum 3 Rotating mechanism 4 Holding mechanism 6 Head unit 7 Recording head 8 Ultraviolet irradiation apparatus 10 Subscanning mechanism 11 Conveyance mechanism 12 Control part

Claims (10)

Image recording method for recording an image by repeating a recording step of discharging ink toward a recording medium and irradiating the ink droplet landed on the recording medium with an active energy ray to cure the ink droplet a plurality of times In
The ink has a static contact angle of 90 to 120 degrees with respect to the recording medium,
The image recorded by performing the recording process a predetermined number of times uses 85% or more of the ink amount required to record a solid image,
In the first recording step, the ink is ejected so that ink droplets that do not form the same pixel do not contact each other after landing on the recording medium, and in the second and subsequent recording steps. the ink discharge so as to fill between the ink droplets which are cured on the recording medium, the diameter of ink droplets that have landed is discharged during the second and subsequent said recording step, the first-time the recording step An image recording method characterized in that the diameter is larger than the diameter of the ink droplet ejected and landed at the time .   The image recording method according to claim 1, wherein the ink has a static contact angle of 10 to 50 degrees between a cured ink droplet and an uncured ink droplet.   The resolution after landing of ink droplets discharged in the first recording step is 2 to 6 times the resolution after landing of ink droplets discharged in the second and subsequent recording steps. The image recording method according to claim 1, wherein the image recording method is an image recording method.   The diameter of the ink droplets ejected and landed in the second and subsequent recording steps is the average value of the distance between the centers of the ink droplets ejected and landed in the first recording step. The image recording method according to claim 1, wherein the image recording method is 5 to 2.5 times. The ink is a UV curable ink, an image recording method according to any one of claims 1 to 4, wherein the surface tension of 0.02~0.06N / m. The ink is a transparent ink. The image recording method according to any one of claims 1 to 5. In an image recording apparatus for recording an image by repeating an operation of ejecting ink toward a recording medium and irradiating the ink droplet landed on the recording medium with an active energy ray to cure the ink droplet a plurality of times ,
The ink has a static contact angle of 90 to 120 degrees with respect to the recording medium,
An image recorded by performing the above operation a predetermined number of times uses 85% or more of an ink amount required to record a solid image,
In the first operation, the ink is discharged so that ink droplets that do not form the same pixel do not contact the recording medium after landing, and in the second and subsequent operations, the recording is performed. and ejecting the ink so as to fill between the ink droplets which are cured on the medium, the diameter of ink droplets that have landed is discharged during the second and subsequent said recording step, when the first time of the recording process An image recording apparatus having a diameter larger than a diameter of an ink droplet ejected and landed on the image. A first image recording apparatus for recording an image on a recording medium;
An operation of ejecting ink droplets toward the recording medium on which an image is recorded by the first image recording apparatus and irradiating the ink droplets with active energy rays to cure the ink droplets is performed a plurality of times. A second image recording device for repeatedly recording an image;
In an image recording system comprising:
The ink used in the second image recording apparatus has a static contact angle with respect to the recording medium of 90 to 120 degrees,
The image recorded by the second image recording apparatus uses 85% or more of the ink amount required to record a solid image, and does not form the same pixel during the first operation. The ink is ejected so that the droplets do not contact the recording medium after landing, and the ink is ejected so as to fill the space between the ink droplets cured on the recording medium in the second and subsequent operations. The diameter of the ink droplet ejected and landed in the second and subsequent recording steps is larger than the diameter of the ink droplet ejected and landed in the first recording step. Image recording system. 9. The image recording system according to claim 8 , wherein the first image recording apparatus is a charge copying type image recording apparatus. The image recording system according to claim 8 or 9 , wherein the toner used by the first image recording apparatus contains a wax.

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