JP2003200564A - Ink jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet printer in which the accuracy and stability of a print image are enhanced by irradiating a recording medium subjected to ink ejection with UV-rays from the rear side. <P>SOLUTION: In the ink jet printer 1, a head 51 mounted on a head carriage 52 ejects UV-curing ink to a recording medium 2 while moving in the horizontal direction. A UV light source 61 provided on the side opposite to the recording face of the recording medium irradiates the rear side of the recording medium 2 subjected to ink ejection with UV-rays. A movable interception plate P interposed between the UV light source 61 and the recording medium 2 is moved through a drive section (not shown) in synchronism with the head carriage 52 and intercepts UV-rays when the head carriage 52 is in a recording region. Since the head carriage 52 is not irradiated with UV-rays, ink in the head 51 does not cure to cause trouble in ink ejection. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer using an ultraviolet curable ink.

[0002]

2. Description of the Related Art In an ink jet printer, an ultraviolet curable ink ejected and landed on a recording medium is irradiated with ultraviolet rays (UV) to cure and fix the ultraviolet curable ink to obtain an image. There is a so-called UV inkjet printer. Conventional UV
In an inkjet printer, a head mounted on a head carriage scans along a recording medium by the movement of the head carriage, and ejects ultraviolet curable ink onto the recording medium to land it. The recording medium on which the ink has landed is irradiated with ultraviolet rays by an ultraviolet light source, and when the ultraviolet curable ink on the recording medium is cured and stabilized, an image is printed.

[0003]

By the way, when the ultraviolet curable ink on the recording medium is irradiated with ultraviolet rays, the surface layer of the ink starts to cure immediately, but it takes time to cure the inside of the ink and A high UV intensity is required to cure as quickly as possible, which limits the design of the UV intensity and the UV irradiation time. Also,
It takes some time for the ink to land on the recording medium until the ultraviolet irradiation ends and the ink is cured and fixed.
In the meantime, ink bleeding or discoloration may occur on the recording medium depending on the surrounding environment, ejection conditions, and the like. In particular, since it is difficult for ultraviolet rays to reach the contact portion of the ink with the recording medium, the contact portion of the ink with the recording medium does not cure easily, and problems such as dot diameter instability and bleeding may occur. An object of the present invention is to irradiate the back surface of the recording medium with ultraviolet rays when the recording medium is a transparent substrate that transmits ultraviolet rays such as vinyl chloride and polypropylene.
It is possible to improve the accuracy of the final image and stabilize it by irradiating ultraviolet rays to the contact area of the ink with the recording medium, shortening the ultraviolet ray irradiation time, stabilizing the ink dot diameter, preventing ink bleeding and discoloration. An object is to provide an inkjet printer.

[0004]

In order to solve the above problems, the invention described in claim 1 is, for example, as shown in FIG.
Head 5 for ejecting ultraviolet curable ink onto recording medium 2
1. An inkjet printer 1 comprising: 1 and ultraviolet irradiation means 6 and 7 for irradiating the ink ejected onto the recording medium with ultraviolet rays, wherein at least a part of the ultraviolet rays emitted from the ultraviolet irradiation means is a recording medium. The back surface opposite to the recording surface on which the ink is ejected is irradiated.

According to the first aspect of the invention, when the recording medium is a transparent base material such as vinyl chloride or polypropylene that transmits ultraviolet rays, the back surface of the recording medium is irradiated with ultraviolet rays, so that the recording medium of ink is used. It is possible to irradiate the contact part with ultraviolet rays. Therefore, by quickly curing the contact surface of the ink with the recording medium and fixing the ink on the recording medium before the shape of the ink collapses, the ink dot diameter is stabilized, ink bleeding prevention and discoloration prevention are achieved, and the final image The accuracy can be improved and stabilized. If both the front surface and the back surface of the recording medium are irradiated with ultraviolet rays, the intensity of ultraviolet rays irradiated onto the ultraviolet curable ink on the recording medium increases. Therefore, it is possible to shorten the time from when the ink lands on the recording medium until it is cured and fixed, and it is possible to prevent the ink from bleeding or discoloring on the recording medium. Furthermore, by shortening the UV irradiation time, the total printing processing time can be shortened, and the length of the UV irradiation range within the transport path of the recording medium can be shortened. Can be converted. When the recording medium is resin, bleeding like paper does not occur, but here, the spread of ink dots in an irregular shape is referred to as bleeding.

According to a second aspect of the present invention, there is provided the ink jet printer according to the first aspect, which has a head carriage 52 which includes the head and reciprocates, and is provided with one or more ultraviolet ray irradiating means. The one ultraviolet irradiating unit 6 irradiates the back surface of the area of the recording medium which overlaps with the recording range in which the head can eject ink onto the recording medium within the moving range of the head that moves together with the head carriage. The ultraviolet irradiation means for irradiating the back surface of the area of the recording medium with ultraviolet rays does not perform ultraviolet irradiation when the head is within the recording range, and when the head is outside the recording range. It is characterized in that it is controlled to perform ultraviolet irradiation.

According to the second aspect of the present invention, the ultraviolet irradiation is performed only when the head carriage is out of the recording range, and the ultraviolet irradiation is not performed when the head carriage is in the recording range. Is not exposed to UV light. Therefore, the ink in the head is not cured by being irradiated with ultraviolet rays. For example, it is possible to prevent the ink in the head ejection port or the ink that is in contact with the head immediately after ejection from being cured at the ejection port of the head and making it difficult to eject the ink.

According to a third aspect of the present invention, there is provided the ink jet printer according to the second aspect, which comprises transporting means 3 and 4 for transporting a recording medium in a direction intersecting with a moving direction of the head carriage, and at least one ultraviolet ray. The irradiating means irradiates the back surface of the recording medium on the downstream side in the carrying direction of the carrying means with ultraviolet rays, and the irradiating means irradiates the back surface of the recording medium on the downstream side in the carrying direction with ultraviolet rays. The irradiating means irradiates ultraviolet rays regardless of the position of the head that moves together with the head carriage,
It is characterized in that non-irradiation is controlled.

According to the third aspect of the invention, it is possible to irradiate the back surface of the recording medium on the downstream side of the head with ultraviolet light regardless of the position of the head. Here, the ultraviolet rays applied to the back surface of the recording medium on the downstream side of the head are not applied to the head carriage, and the ink in the head is hardened so that ejection of the ink is not made difficult. Therefore, it is possible to more efficiently irradiate the back surface of the recording medium with ultraviolet rays while preventing the ink from being cured in the head, and it is possible to shorten the ultraviolet ray irradiation time.

According to a fourth aspect of the present invention, there is provided the ink jet printer according to the third aspect, wherein ultraviolet irradiation means for irradiating the back surface of the area of the recording medium with ultraviolet rays and downstream of the area of the recording medium in the carrying direction. The ultraviolet irradiation means for irradiating ultraviolet rays to the back surface of the side is capable of switching between irradiation and non-irradiation of ultraviolet rays by setting.

According to the fourth aspect of the present invention, either the back surface of the area of the recording medium that overlaps the print range where ink can be ejected onto the recording medium or the back surface of the area downstream of the area in the transport direction is required. Only one side can be irradiated with ultraviolet light. For example, depending on the nature of the ink or recording medium,
If UV irradiation is required or effective only on the downstream side of the region, the UV irradiation on the back surface of the region is set to non-irradiation, and the UV irradiation on the back surface on the downstream side is irradiation. Just set it. By doing so, it is not necessary to control the UV irradiation by blocking the UV irradiation in order to prevent the UV irradiation to the head carriage. In addition, the intensity of ultraviolet rays applied to the recording medium and the ink can be set more freely.

The invention according to claim 5 is the ink jet printer according to any one of claims 1 to 4,
The recording surface of the recording medium is provided with both an ultraviolet ray irradiating means and an ultraviolet ray irradiating means for irradiating the back surface of the recording medium with ultraviolet rays. The feature is that irradiation can be switched by setting.

According to the fifth aspect of the present invention, the recording medium is a transparent base material that transmits ultraviolet rays, and the back surface is irradiated with ultraviolet rays only when the irradiation of ultraviolet rays on the rear surface is effective, and the recording medium is exposed to ultraviolet rays. In the case of an opaque base material that does not pass through, if the back surface is not effectively irradiated with ultraviolet light, the back surface can be set not to be irradiated with ultraviolet light. Therefore, useless irradiation of ultraviolet rays can be omitted, and power can be saved.

According to a sixth aspect of the present invention, there is provided an ink jet printer according to the fifth aspect, which comprises a sensor 10 for measuring a transmission state of ultraviolet rays of a recording medium, and the ultraviolet ray is provided on the back surface of the recording medium based on the measurement of the sensor. It is characterized by comprising a switching means for switching the setting of whether or not to irradiate the ultraviolet rays of the ultraviolet ray irradiating means for irradiating.

According to the sixth aspect of the present invention, since it is possible to automatically set the irradiation or non-irradiation of the ultraviolet rays by the sensor, the transparent recording medium and the opaque recording medium are mixed and printed. In such a case, it is possible to save the labor of manually setting the ultraviolet irradiation control one by one, and never forget to make the setting, so that unnecessary ultraviolet irradiation can be surely omitted to save power.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. The inkjet printer 1 exemplified in the present embodiment ejects and cures the ultraviolet curable ink onto a transparent recording medium 2 such as vinyl chloride or polypropylene that transmits ultraviolet rays, and the recording medium 2 on which the ink has landed the ultraviolet rays. Is applied to cure and fix the ink to perform printing.

First, the configuration of this embodiment will be described. As shown in FIG. 1, the inkjet printer 1 schematically includes conveyance rollers 3 and 4 (conveying means) that conveys a recording medium 2, an ink ejection unit 5 that ejects ultraviolet curable ink onto the recording medium 2, and an ink ejection unit. A back surface UV irradiation section 6 (UV irradiation means) for irradiating the back surface of the recording medium 2 thus irradiated with UV rays,
A blocking plate P for blocking the ultraviolet rays from the back surface ultraviolet irradiation section 6,
Separation plate Q for separating the ultraviolet rays from the back surface ultraviolet ray irradiation section 6,
A surface ultraviolet irradiation unit 7 (ultraviolet irradiation means) that irradiates the surface of the recording medium 2 on which ink is ejected with ultraviolet rays, and a sensor 10 that measures the ultraviolet transmission state of the recording medium are provided.

The transport rollers 3 and 4 cooperate with each other to move the recording medium 2 along the transport direction D so as to pass through the sensor 10, the ink ejection unit 5, the back surface ultraviolet irradiation unit 6 and the front surface ultraviolet irradiation unit 7. Transport.

The sensor 10 is installed on the most upstream side of the conveyance path of the recording medium 2, measures the ultraviolet transmission state of the recording medium 2, and controls the operation and non-operation of the back surface ultraviolet irradiation unit 6 based on the measurement result. To do.

The ink ejecting section 5 ejects the ultraviolet curing ink to land it on the head 51, a head carriage 52 having a plurality of the heads 51, and as shown in FIG. A position 8, a maintenance unit 9 for performing maintenance of the head 51, a carriage rail 53 for guiding the head carriage 52 along the longitudinal direction (direction of arrow A) when moving,
And a control unit (not shown) for controlling these units.

The home position 8 is, as shown in FIG.
The same number of moisturizing caps 81 that moisturize the lower surface of the head 51 are provided, and the lower surface of the head 51 is covered and hermetically moisturized while the head carriage 52 is on standby.

As shown in FIG. 2, the maintenance unit 9 covers the lower surface of the head 51 and seals it.
A suction cap 91 for sucking ink from the ejection port, a blade 93 for rubbing the lower surface of the head 51 to wipe ink remaining at the ejection port after the suction cap 91 sucks ink, and ejection of the recording head 51 An ink receiving portion 92 for receiving the ink ejected from the curing is integrally provided on the upper surface (the surface facing the ejection port of the head 51). A plurality of suction caps 91 (two in this embodiment are used).
They are provided side by side, and during maintenance,
It is possible to suck a plurality of heads 51 at one time. Below the suction cap 51, a suction pump 94 for sucking the inside of the space formed by the suction cap 91 and the lower surface of the head 51 is provided, and the ink sucked from the ejection port by the suction pump 94 is the waste ink. It is discharged to the tank 95.

In the range where the head carriage 52 moves in the longitudinal direction (direction of arrow A), as shown in FIG. 2, the range in which the head 51 ejects ink to land on the recording medium is the recording area and other areas. That is, the range in which the home position 8 and the maintenance unit 9 are installed is the non-recording area. Further, here, a recording medium having a maximum width (width along the moving direction of the head carriage) that can be printed by this inkjet printer is used.

The back surface UV irradiator 6 comprises a back surface UV light source 61, a blocking plate P and a separating plate Q which are arranged on the back surface side of the recording surface of the recording medium. The blocking plate P is movably installed between the back surface ultraviolet light source 61 and the recording medium 2, and is driven by a drive unit (not shown) controlled by a control unit (not shown).
A cutoff position PC corresponding to the position of the head carriage 52
And the standby position PD in the direction of arrow B. Separator Q
Between the recording medium and the rear surface ultraviolet light source 61 so that the ultraviolet light from the rear surface ultraviolet light source 61 is divided into the amount of irradiation of the recording medium in the recording step and the amount of irradiation of the recording medium in the recording step. It is installed in. Here, the recording step is a step in which the head that moves with the movement of the head carriage ejects ink onto the recording medium, and after the recording step, the recording medium ejected ink in the recording step is the head carriage. The step of being carried to the downstream side by the carrying means for carrying in a direction intersecting with the moving direction of FIG.

The surface ultraviolet light irradiating section 7 is provided with a surface ultraviolet light source 71 arranged on the surface side of the recording surface of the recording medium.

Next, a mode of printing performed by using the ink jet printer 1 of this embodiment will be described. In addition,
For printing, the recording medium 2, the sensor 10, the ink ejection unit 5,
It is conveyed by the cooperation of the conveying rollers 3 and 4 so as to pass through the back surface ultraviolet irradiation section 6 and the front surface ultraviolet irradiation section 7, and in the course of the conveyance, the ultraviolet curable ink is ejected and landed on the recording medium 2 so that the ultraviolet irradiation is performed. It is performed by curing and fixing the ultraviolet curable ink landed by.

First, the recording medium 2 is measured upstream of the transport path before the ink is ejected by the sensor 10 for the state of transmission of ultraviolet rays, and based on the measurement result, a control unit (not shown) irradiates the rear surface with ultraviolet rays. Control the operation of the part 6. That is, when the recording medium 2 sufficiently transmits the ultraviolet rays, the back surface ultraviolet irradiation unit 6 is controlled to operate by turning on the back surface ultraviolet light source 61, and when the recording medium 2 does not sufficiently transmit the ultraviolet rays, the back surface ultraviolet light is emitted. The irradiation unit 6 is controlled so that the back surface ultraviolet light source 61 is turned off and does not operate. In addition, in this embodiment, since the recording medium 2 transmits ultraviolet rays, the rear surface ultraviolet irradiation section 6 is controlled to operate. When ultraviolet rays are radiated to the back surface of the recording medium, if the recording medium does not sufficiently transmit the ultraviolet rays, the irradiated ultraviolet rays are naturally reflected or absorbed by the recording medium, and the ink ejected onto the recording medium is reflected. If it does not reach, there is no point in irradiating the back surface of the recording medium with ultraviolet rays. Therefore, the sensor 10 determines whether the ultraviolet irradiation is activated or inactivated by the recording medium 2.
By controlling according to the UV transmission state, unnecessary use of back surface UV irradiation can be omitted, and power saving can be achieved. Further, by controlling the operation of the back surface UV irradiation by using a sensor, it is necessary to frequently switch the back surface UV irradiation unit 6 such as alternately printing a recording medium that transmits the UV light and a recording medium that does not transmit the UV light. Even in such a case, there is no need to manually perform each one, and it is possible to prevent forgetting to switch. In addition, when it is not necessary to frequently switch the operation of the ultraviolet irradiation unit 6 when printing only a transparent recording medium or only an opaque recording medium, the ultraviolet irradiation unit 6 is manually operated. A switching means for switching the operation of the above may be provided, and both an automatic switching means using a sensor and a manual switching means may be provided.

Next, in the ink ejecting section 5, the head carriage 52 is moved in the direction of arrow A in FIG. 2 to cause the head 51 to scan along the recording medium, while the ultraviolet curing ink is ejected from the head 51 onto the recording medium. Discharge and land on. At this time, the conveyance of the recording medium 2 is synchronized with the movement of the head carriage 52.

The back surface of the recording medium 2 from which the ink has been ejected is irradiated with ultraviolet rays by the back surface ultraviolet light source 61 of the back surface ultraviolet irradiation unit 6 which is controlled to operate based on the measurement result of the sensor 10. By irradiating the back surface of the recording medium 2 with ultraviolet rays, the contact portion of the ink with the recording medium can be irradiated with ultraviolet rays. Therefore, by quickly curing the contact surface of the ink with the recording medium and fixing the ink on the recording medium before the shape of the ink collapses, the ink dot diameter is stabilized, ink bleeding prevention and discoloration prevention are achieved, and the final image The accuracy can be improved and stabilized. Further, by irradiating both the front surface and the back surface of the recording medium 2 with ultraviolet rays, the intensity of ultraviolet rays with which the ultraviolet curable ink on the recording medium 2 is irradiated is increased. Therefore, it is possible to shorten the time from when the ink lands on the recording medium 2 until it is cured and fixed, and it is possible to prevent the ink from bleeding or discoloring on the recording medium 2. Furthermore, by shortening the ultraviolet irradiation time, it is possible to shorten the length of the range where the ultraviolet irradiation is performed in the conveyance path of the recording medium 2, so that the main body of the inkjet printer 1 can be downsized.

In the recording process in which ink is ejected and landed by the head 51, when the head carriage 52 is in the recording area, the shield plate P is moved in the direction of arrow B by the drive unit controlled by the control unit (not shown). It is arranged at the position PC to block the ultraviolet light applied to the head carriage 52. Therefore, the ink in the head is not cured by being irradiated with ultraviolet rays. For example, it is possible to prevent the ink in the head ejection port or the ink that is in contact with the head immediately after ejection from being cured at the ejection port of the head and making it difficult to eject the ink. When the head carriage 52 is in the non-recording area, the control unit controls the drive unit to move the blocking plate P in the direction of arrow B and place the blocking plate P at the standby position PD. At the standby position PD, the blocking plate P does not block the ultraviolet rays radiated to the back surface of the recording medium 2 in the recording area, so that the back surface of the recording medium 2 can be radiated with the ultraviolet rays. In this way, by irradiating the back surface of the recording medium 2 in the recording step with ultraviolet rays, the contact portion of the ink with the recording medium 2 can be irradiated with ultraviolet rays immediately after the ink has landed on the recording medium 2. The dot diameter can be stabilized and bleeding and discoloration can be prevented more effectively. Further, by starting the irradiation of the recording medium 2 with ultraviolet rays in the recording step, it is possible to shorten the time from the landing of the ink on the recording medium 2 to the end of the ultraviolet irradiation. Further, the total printing processing time can be shortened by shortening the ultraviolet irradiation time, and the length of the range for performing the ultraviolet irradiation in the conveyance path of the recording medium 2 can be shortened. Can be converted.

As a method of preventing the head 51 from being irradiated with ultraviolet rays, it is possible to turn off the power of the back surface ultraviolet light source 61 to interrupt the irradiation of ultraviolet rays when the head carriage 52 is in the recording area. If the light source is turned off and then turned on again, it takes time to obtain sufficient ultraviolet rays again. Therefore, there is a time lag between the irradiation and non-irradiation of the ultraviolet rays, which is not preferable from the viewpoint of shortening the total printing processing time.

Further, in the back surface UV irradiation, the UV rays irradiated are separated by the separating plate Q into the UV rays irradiated to the back surface of the recording medium 2 in the recording step and the UV rays irradiated to the back surface of the recording medium 2 after the recording step. Is separated into
Therefore, the ultraviolet rays applied to the back side of the recording medium after the recording step are not applied to the head carriage due to reflection or the like. Therefore, when the blocking plate P is arranged at the blocking position PC, the ultraviolet rays applied to the head carriage are completely blocked, and the head is not irradiated with the ultraviolet rays and the ink in the head is not cured.

As described above, ink is ejected and landed,
The recording medium 2 irradiated with ultraviolet rays from the back surface side is further irradiated with ultraviolet light from the front surface side by the front surface ultraviolet light source 71 in the front surface ultraviolet light irradiation unit 7 while being conveyed by the rollers 3 and 4.

If backside UV irradiation is not required in the recording process, the setting of the control unit may
The blocking plate P may be always arranged at the blocking position PC without moving in the direction of the arrow B. By doing so, it is not necessary to drive the blocking plate P to block the irradiation of the head carriage 52 with ultraviolet rays, and it is possible to not only save the power for moving the blocking plate P, but also
It is possible to avoid wasteful consumption of parts relating to the movement of the blocking plate P. On the other hand, when it is not desired to irradiate the back surface ultraviolet ray after the recording step, for example, a blocking plate (not shown) is provided between the back surface of the recording medium 2 after the recording step and the back surface ultraviolet light source 61, and the recording medium 2 after the recording step is provided. You may make it block the ultraviolet rays with which the back surface of this is irradiated. By doing so, it is possible to adjust the intensity of ultraviolet rays applied to the recording medium 2 and the ink, and it is possible to prevent inconveniences such as deterioration of quality that may be caused by excessive irradiation of ultraviolet rays.

In the recording step, as a method of blocking the head from being irradiated with ultraviolet rays, a blocking plate having a size that covers the head is provided between the recording medium and the back surface ultraviolet light source 61 so as to face the head. It may be arranged and moved in synchronization with the head. By doing so, it is possible to irradiate the portion of the recording medium in the recording step during the recording process with the ultraviolet light immediately after the head has passed without irradiating the head within the recording range with the ultraviolet light.

[0036]

According to the ink jet printer of the first aspect of the present invention, since the back surface of the recording medium is irradiated with ultraviolet rays, the contact portion of the ink with the recording medium can be irradiated with ultraviolet rays. Therefore, by quickly curing the contact surface of the ink with the recording medium and fixing the ink on the recording medium before the shape of the ink collapses, the ink dot diameter is stabilized, ink bleeding prevention and discoloration prevention are performed, and the final image The accuracy of can be improved and stabilized. If both the front surface and the back surface of the recording medium are irradiated with ultraviolet rays, the intensity of ultraviolet rays irradiated onto the ultraviolet curable ink on the recording medium increases. Therefore, it is possible to shorten the time from when the ink lands on the recording medium until it is cured and fixed, and it is possible to prevent the ink from bleeding or discoloring on the recording medium. Furthermore, by shortening the ultraviolet irradiation time, it is possible to shorten the total printing processing time, and also because it is possible to shorten the length of the range in which the ultraviolet irradiation is performed in the transport path of the recording medium,
The main body of the inkjet printer device can be miniaturized.

According to the ink jet printer of the second aspect of the present invention, since the head carriage is not irradiated with ultraviolet rays, the ink of the head is not irradiated with ultraviolet rays and cured. For example, it is possible to prevent the ink in the head ejection port or the ink that is in contact with the head immediately after ejection from being cured at the ejection port of the head and making it difficult to eject the ink.

According to the ink jet printer of the third aspect of the invention, it is possible to irradiate the back surface of the recording medium on the downstream side with ultraviolet light regardless of the position of the head. Therefore, it is possible to more efficiently irradiate the back surface of the recording medium with ultraviolet rays while preventing the ink from being cured in the head, and it is possible to shorten the ultraviolet ray irradiation time.

According to the ink jet printer of the fourth aspect of the invention, it is possible to irradiate the back surface of the recording medium with ultraviolet rays at either the recording step or after the recording step. Therefore, when the UV irradiation is performed only after the recording process, it is not necessary to control the UV irradiation by blocking the UV irradiation to prevent the UV irradiation to the head carriage. In addition, the intensity of ultraviolet rays applied to the recording medium and the ink can be set more freely.

According to the ink jet printer of the fifth aspect of the invention, the recording medium is a transparent substrate which transmits ultraviolet rays, and the ultraviolet rays are radiated to the back side only when the ultraviolet rays are effectively radiated to the back side for recording. When the medium is an opaque base material that does not transmit ultraviolet rays, and the irradiation of ultraviolet rays on the rear surface is not effective, it can be set so that the rear surface is not irradiated with ultraviolet rays. Therefore, useless irradiation of ultraviolet rays can be omitted, and power can be saved.

According to the ink jet printer of the sixth aspect of the present invention, it is possible to automatically set the irradiation or non-irradiation of ultraviolet rays by the sensor, so that a transparent recording medium and an opaque recording medium are mixed. For example, when printing is performed, it is possible to save the labor of manually setting the ultraviolet irradiation control one by one, and never forget to set the setting, and it is possible to reliably omit unnecessary ultraviolet irradiation and save power.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part for explaining a printing process of an inkjet printer according to an embodiment to which the present invention is applied.

FIG. 2 is a front view for explaining a recording area and a non-recording area of the inkjet printer of FIG.

[Explanation of symbols]

1 inkjet printer 2 Transparent recording medium 3.4 Transport rollers (transport means) 5 Ink ejection section 51 heads 52 head carriage 53 Carriage rail 6 Backside UV irradiation part (UV irradiation means) 61 Backside UV light source P blocking plate Q separation plate 7 Surface UV irradiation part 71 Surface UV light source 8 home positions 9 Maintenance unit 10 sensors

Claims (6)

[Claims] 1. An inkjet printer comprising: a head for ejecting an ultraviolet curable ink onto a recording medium; and an ultraviolet irradiation means for irradiating the ink ejected onto the recording medium with ultraviolet rays. An inkjet printer characterized in that at least a part of the generated ultraviolet rays is applied to the back surface of the recording medium opposite to the recording surface on which the ink is ejected. 2. A head carriage that includes the head and reciprocates, and includes one or more ultraviolet ray irradiating means, wherein at least one ultraviolet ray irradiating means moves with the head carriage. Of the above, the head is to irradiate ultraviolet rays on the back surface of the area of the recording medium that overlaps the recording range in which ink can be ejected onto the recording medium, and the ultraviolet irradiation means for irradiating the back surface of the area of the recording medium with ultraviolet rays is 2. The control is such that the ultraviolet irradiation is not performed when the head is within the recording range, and the ultraviolet irradiation is performed when the head is outside the recording range. Inkjet printer. 3. A transporting means for transporting a recording medium in a direction intersecting a moving direction of the head carriage, wherein at least one ultraviolet irradiating means is located downstream of the area of the recording medium in the transporting direction of the transporting means. Ultraviolet irradiation means for irradiating the back surface with ultraviolet rays, and for irradiating the back surface on the downstream side of the recording medium in the transport direction with ultraviolet rays is an ultraviolet irradiation regardless of the position of the head that moves together with the head carriage. 3. The non-irradiation is controlled.
The described inkjet printer. 4. An ultraviolet ray irradiating means for irradiating the back surface of the area of the recording medium with ultraviolet rays and an ultraviolet ray irradiating means for irradiating the back surface of the recording medium on the downstream side of the area of the recording medium in the carrying direction with the ultraviolet ray, respectively. The inkjet printer according to claim 3, wherein non-irradiation can be switched by setting. 5. An ultraviolet irradiation means for irradiating the back surface of a recording medium with ultraviolet light, comprising both ultraviolet irradiation means for irradiating the recording surface of the recording medium with ultraviolet light and ultraviolet irradiation means for irradiating the back surface of the recording medium with ultraviolet light. The inkjet printer according to any one of claims 1 to 4, wherein the irradiation and non-irradiation of ultraviolet rays can be switched by setting. 6. A switch for switching between setting of UV irradiation and non-irradiation of a UV irradiation means for irradiating the back surface of the recording medium with UV based on the measurement of the sensor, the sensor including a sensor for measuring the UV transmission state of the recording medium. The inkjet printer according to claim 5, further comprising means.