JP2005349636A - Liquid droplet discharging head and image recorder carrying this head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of a conventional image forming apparatus which uses UV ink that an irradiation part of UV light is rendered large, power consumption and heating are also large and the quality of a recording medium is degraded by the UV light. <P>SOLUTION: The liquid droplet discharging head is constituted by setting and uniting the UV light irradiation part for hardening the UV ink integrally with a downstream side side face of the liquid droplet discharging head where an ink row with many nozzles for discharging liquid droplets of the UV ink arranged is disposed, and arranging the head units at a carriage for each color in accordance with a transfer direction. The image recorder carries this head. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet type droplet discharge head for recording an image by discharging droplets onto a recording medium, and an image recording apparatus equipped with the head.

  In general, as an image recording apparatus by discharging ink such as an ink jet printer as droplets onto a recording medium, an apparatus using UV (ultraviolet) curable ink (hereinafter referred to as UV ink) in addition to a normal solvent ink. Is also known. This UV ink makes it possible to form an image on a recording medium that does not absorb or is difficult to absorb by utilizing the property of solidifying the discharged droplets by irradiating ultraviolet rays. Furthermore, since it does not vaporize like solvent inks, its use is expanding by taking advantage of features that solvent inks do not have, such as no pollution, high safety, and instant fixing.

  As an image recording apparatus using UV ink, for example, Patent Document 1 discloses an ink jet printer including a head carriage, a recording head, an irradiation unit, a head scanning unit, a medium conveying unit, a control unit, and the like. In this ink jet printer, as shown in FIG. 16, a head carriage 92 is installed above the recording medium M, and a plurality of recording heads 93 corresponding to the number of colors used for image printing on the recording medium M are not shown. The discharge ports are arranged to be adjacent to the recording medium M. Further, a radiation irradiation means 91 is provided above the head carriage 92.

  Further, a radiation transmitting portion 94 made of a hole is provided between the recording heads 93. The shapes (diameters) of these radiation transmitting portions 94 are set to be substantially the same as or larger than the region where the recording head 92 ejects a single droplet to eject UV ink.

  That is, the irradiating means 91 irradiates the entire area of the landable region E with ultraviolet rays downward as indicated by arrows shown in FIG. At this time, of the ultraviolet rays irradiated toward the head carriage 2, the ultraviolet rays irradiated toward the recording head 93 and the vicinity thereof are blocked by the head carriage 92. However, the ultraviolet rays irradiated toward the radiation transmitting portion 94 pass through the radiation transmitting portion 94 and reach the recording medium M.

  Similarly, Patent Document 2 discloses an ink jet printer in which heads and UV light sources are alternately arranged.

  In this ink jet printer, as shown in FIG. 17, a plurality of heads 102 and a plurality of UV light sources 103 are alternately attached to the carriage 100 in a line in the main scanning direction A and arranged at equal intervals. . Further, a cover 101 is attached to the carriage 100 so as to cover these UV light sources 103. With such a configuration, as the carriage 100 moves, each head 102 and each UV light source scan and move integrally on a recording medium (not shown).

In this configuration, each cover 101 covers the UV light source 103 from above so that the ultraviolet light from the UV light source is shielded so that the head 102 is not exposed to the ultraviolet light. Exposed to ultraviolet light from. The length of the UV light source 103 in the sub scanning direction B is longer than or substantially equal to the length of the head 102 in the sub scanning direction B.
JP 2003-145741 A JP 2003-285426 A

However, the above-described apparatus according to Patent Document 1 has a configuration in which the irradiation means is arranged on the fixed side with respect to the carriage that moves by scanning. For this reason, it is necessary to irradiate the entire range in which the carriage moves. As a result, an increase in the size of the irradiation unit is inevitable, and there is a problem that power consumption and heat generation increase.
Furthermore, the apparatus according to Patent Document 2 has a configuration in which a light source is arranged on a carriage that moves in a scanning manner. Therefore, compared with the apparatus shown in Patent Document 1, since nine UV light sources and eight heads are alternately arranged separately, the arrangement space for the UV light source is required and the size is increased. Further, if all nine UV light sources are made to emit light, the power consumption and heat generation are further increased, and the amount of ultraviolet irradiation to the recording medium is also large. Therefore, when recording is performed on a recording medium having a small allowable range of ultraviolet irradiation. There is a possibility of deteriorating the quality of the recording medium.

  Accordingly, the present invention is equipped with a droplet discharge head that discharges light-curable ink, has a small power consumption and heat generation due to light irradiation, and has a small and simple configuration, and an image on which this head is mounted. An object is to provide a recording apparatus.

  In order to achieve the above object, the present invention provides a liquid droplet ejection head having a nozzle for ejecting a photocurable ink that is cured by irradiation of light onto a recording medium, and light applied to the photocurable ink ejected to the recording medium. An image recording apparatus having a light irradiation unit that irradiates the recording medium and a scanning mechanism that changes a relative position of the recording medium and the droplet discharge head, wherein the droplet discharge head is a photocurable ink based on discharge information. And the light irradiation unit provides an image recording apparatus in which the amount of irradiation light is controlled in relation to the discharge information.

  Also, a droplet discharge head having a nozzle that discharges a photocurable ink that is cured by irradiation of light to a droplet discharge head recording medium, the light irradiating the photocurable ink discharged to the medium with light There is provided a droplet discharge head having an irradiation light source, wherein the light irradiation light source is integrated with the droplet discharge head.

  According to the present invention, a droplet discharge head that discharges photocurable ink is mounted, and a droplet discharge head that consumes less power and generates less heat and has a small size and a simple configuration, and the head are mounted. An image recording apparatus can be provided.

  Furthermore, by controlling the light irradiation unit in relation to the discharge information of the droplet discharge head, the total emission time can be reduced, the power consumption and heat generation of the light irradiation unit can be reduced, and the droplet discharge With the configuration in which the light irradiation unit for curing the ink is integrally formed on the head, it is easy to dispose the droplet head and the light irradiation unit in the image recording apparatus, and the miniaturization can be realized.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a schematic configuration example of an image recording apparatus according to the first embodiment of the present invention. The image recording apparatus of the present invention is an ink jet printer, copier, or facsimile that performs recording by ejecting droplets of photo-curing ink having a property of being cured by UV light onto a recording medium such as paper or plastic film. The present invention can be applied to a printing apparatus such as an adhesive, a small amount of adhesive discharge device, an inkjet printer used for a small amount of droplet discharge in an LCD color filter manufacturing apparatus, and the like.

  In the following description, UV ink that is cured by ultraviolet light (hereinafter referred to as UV light) is taken as an example of photo-curing ink, and droplets are landed on a recording medium such as paper or resin film as an image recording apparatus. An example is an inkjet printer that performs recording. In the drawing, the conveyance direction of the recording medium is the X-axis direction or the sub-scanning direction, and the direction orthogonal to the conveyance direction is the Y-axis direction, the main scanning direction, or the width direction of the recording medium. The direction perpendicular to the X-axis and Y-axis directions is taken as the Z-axis direction or the vertical direction.

  In this image forming apparatus, a plurality of recording heads are fixed, and each of the four different colors (for example, K: Black, C: Cyan, M: Magenta, Y: Yellow) is ejected and conveyed. For example, an ink jet printer that forms a color image by landing on a recording medium made of recording paper or the like.

  As shown in FIG. 1, this image forming apparatus is roughly divided into a medium supply / discharge mechanism 1 for supplying and discharging a recording medium, a transport mechanism 2 for transporting the recording medium during recording, and UV ink on the recording medium. An image forming mechanism 3 that discharges and cures to form an image, a maintenance mechanism 4 that maintains a recording head, an ink supply and storage mechanism 5 that supplies and stores UV ink, and a control device 6 that controls these mechanisms Consists of.

These mechanisms will be described with reference to FIG.
First, the medium supply / discharge mechanism 1 is removed from a recording medium supply base 12 loaded with a recording medium 11, a paper feed roller 13 that contacts the uppermost surface of the recording medium 11 and feeds the recording medium 11. The separation roller 14 that abuts the back surface of the recording medium 11 and acts so that the recording medium 11 overlaps and is not taken out, and the leading end of the recording medium 11 is abutted in a stopped state to correct the inclination, and then the recording is performed on the transport mechanism side. A registration roller pair 15 for feeding the medium, a paper discharge roller pair 16 for discharging the recording medium 11 on which an image is formed from the transport mechanism 2, and a paper discharge tray 17 for storing the discharged recording medium 11.

  Next, the transport mechanism 2 mainly includes a belt platen unit 18 and a platen vertical movement mechanism (not shown). The belt platen unit 18 is provided with, for example, two suction fans 20 for making a negative pressure inside the suction chamber 19.

  In addition, a driving roller 21, a driven roller 23, and a tension roller 22 are disposed on the upstream side, the downstream side, and the lower side in the conveyance direction of the suction chamber 19, and a belt 24 is rotatably attached so as to surround the periphery. The belt 24 has a structure in which air is allowed to pass using a rubber material or the like, for example, a structure in which a large number of suction holes are opened or a mesh structure. The platen is rotated in contact with the surface of the platen 25. With such a structure, the recording medium 11 is conveyed while being attracted to the platen side together with the belt 24 by the suction fan 20.

  As shown in FIG. 2, the image forming mechanism 3 is arranged to face the belt platen unit 18 (belt conveying surface), and the head portions 9K, 9C, 9M, and 9Y of four colors K, C, M, and Y are disposed. It is comprised by the carriage 31 which has arrange | positioned three identical head units 30 which have. The head portion 9K discharges the black K UV ink, similarly the cyan head portion 9C, the magenta head portion 9M, and the yellow head portion 9Y. Each color head has the same structure except for the UV ink to be mounted. In the following embodiments, the head portion is irradiated with UV light mainly composed of an ink head main body mainly composed of nozzles for discharging UV ink and ink chambers, and an ultraviolet light emitting diode (hereinafter referred to as ultraviolet LED) described later. It is assumed that the parts are integrally attached to form a unit.

  In the maintenance mechanism 4, similarly to the head unit 9, the maintenance unit 8 is disposed to face the belt conveyance surface. Accordingly, the maintenance unit 8 is disposed on the downstream side in the transport direction, and the head unit 30 is disposed on the upstream side thereof. Each unit of the medium supply / discharge mechanism 1, the transport mechanism 2, the image forming mechanism 3, and the maintenance mechanism 4 described above is mounted on a frame 32.

The ink supply / accommodating mechanism 5 mainly includes a plurality of bottles 26 loaded with the four color UV inks, a sub tank 27 serving as a tank for supplying UV ink from the bottles 26 to the recording head, and unnecessary. A suction pump 28 for sucking in UV ink and a waste liquid bottle 29 for collecting and storing unnecessary UV ink.
The bottle 26 is loaded with the four color UV inks at the uppermost position in the ink flow path at the top of the image forming apparatus main body, and is arranged as bottles 26K to 26Y. Further, the bottle 26 is connected to the sub tank 27 by a supply path (not shown). The UV ink overflowed in the sub tank 27 is stored in the waste liquid bottle 29 by the suction pump 28.

Next, each component described above will be described in detail.
First, the head will be described with reference to FIGS.
The ink head main body in this embodiment is an ink jet printer head in which an ink chamber is formed by a wall of a piezoelectric member, and droplets are ejected by deformation of the piezoelectric member. Of course, other methods such as other so-called bubble jet methods and structures using MEMS may be used. A UV light irradiation unit 50 that cures UV ink is integrally attached to the ink head main body to constitute the head unit 9.
The head unit 9 has a nozzle unit 41 for image recording. A nozzle plate 46 is attached to the surface of the nozzle unit 41 facing the recording medium 11 so that a nozzle row 48 in which a plurality of nozzles 47 are arranged is opened. The nozzle unit 41 is composed of a piezoelectric member (not shown), and an ink chamber corresponding to each nozzle partitioned by a wall is provided inside. The piezoelectric member is deformed by applying a voltage to the piezoelectric member in the ink chamber corresponding to each nozzle 47, and a droplet of UV ink is ejected from the desired nozzle 47.

  For example, in one nozzle plate 46, a nozzle array 48 composed of about 1240 nozzles 47 extends in the Y direction orthogonal to the recording medium conveyance direction (X direction), and has an interval of 300 dpi (84.6 μm). ), One nozzle row 48 is formed. Here, the width W2 of the nozzle row 48 is, for example, 105 mm. Of course, it is not limited to this value. Providing such a narrow pitch nozzle array to the end of the nozzle plate 47 is difficult because the required rigidity of the wall of the piezoelectric member cannot be ensured. For this reason, the area | region of the width | variety W3 in which the nozzle 47 is not opened is provided in the both ends outer side of the nozzle row 48. FIG. In addition, the width which becomes the largest external dimension of the nozzle plate 46 and the head part 9 around the nozzle row in the Y direction is W2 + 2 × W3 as the total width W1. In this embodiment, the width W3 is 5 mm, and the total width W1 is 115 mm.

  The nozzle unit 41 is bonded and fixed to a head base 42 made of aluminum die cast that also serves as heat dissipation. A printed circuit board 43 is screwed to the head base 42. On the printed circuit board 43, driving wirings for the respective ink chambers of the nozzle block 41 are formed, and a head driving circuit 45 is mounted.

  The UV light irradiation unit 50 is provided on the surface of the head base 42 opposite to the surface on which the nozzle unit 41 is provided so that the ultraviolet LEDs 51a and 51b expose the UV light irradiation portions (light emitting portions). A lens 52 is provided for each. That is, as shown in FIGS. 4 and 5, two holes 42a are opened in the head base 42, and the ultraviolet LEDs 51a and 51b fixed to the printed circuit board 43 by soldering are fitted with UV light irradiated portions from these holes 42a. It is mounted to wear. For these ultraviolet LEDs 51a and 51b, AIGaNIn, diamond, or the like is used as a light emitting chip, and wavelengths of about 180 nm and 350 nm are selected in accordance with the wavelength sensitivity of the UV ink to be used. A light receiving element for monitoring the amount of light is disposed inside the ultraviolet LEDs 51a and 51b, and is used for monitoring and controlling the amount of light emitted. The lenses 52 are bonded and fixed so as to cover the ultraviolet LEDs 51a and 51b protruding from the head base. These lenses 52 have a reflecting surface 52a and a lens surface 52b.

  As shown in FIGS. 6 and 7, in the head unit 9 configured as described above, the UV light 53 emitted from the ultraviolet LEDs 51a and 51b is reflected by the reflecting surface 52a and enters the lens surface 52b. An optical system is provided on the lens surface 52b so as to diverge light in the nozzle row 48 direction (Y direction) and to collect light in a direction orthogonal to the nozzle row 48 in the transport direction (X direction) of the recording medium 11. . The UV light 53 has an elliptical shape on the recording medium 11 as shown in FIG. In addition, as shown in FIG. 6, the UV light emitted from the two ultraviolet light sources 51 a and 51 b are formed so as to overlap each other, and the light intensity in the peripheral portion of the UV light 53 decreases. To compensate for the amount of light.

  Next, the head unit 30 will be described in detail with reference to FIGS.

  The head unit 30 (for example, 30A) has four color head portions 9K-1, 9C-1, and 9M at the head mounting portion 33h of the head plate 33 from the upstream side (sheet feeding side) in the conveyance direction of the recording medium 11. -1 and 9Y-1 in order of screws 35. At this time, the printed circuit board 43 and the connector 43a are inserted into the opening 33e of the head plate 33, and a cable (not shown) is connected to the connector 43a.

  In such a configuration, one head unit 30 can perform four-color image formation in the width W2 of the nozzle row 48 formed on the nozzle plate 46 of one head unit 9 as shown in FIG. The width in the Y direction of the head mounting portion 33h of the head plate 33 is the same as the entire width W1 of the head portion 9 in the Y direction, and the other width W4 is smaller than the width W2 of the nozzle row 48, and further W4 ≦ W2−. It is set to satisfy 2 * W3.

  Further, as shown in FIG. 8, the distance B2 between the head portions 9 in the peripheral portion of the nozzle plate 46 of the adjacent head portions 9 is larger than the thickness B1 including the light 53 in the X direction of the head portion 9 in the peripheral portion of the nozzle plate 46. Is the same or larger. In the present embodiment, the interval B1 is 6 mm and the interval B2 is 6 mm. With such a configuration, the head unit 30 in which each of the four head portions 9 is attached to the head plate 33 is located near the nozzle plate 46 of the head portion 9 from the head plate 33 when viewed from the Z direction that is the thickness direction of the recording medium. The head end portions 9a on both sides in the Y direction protrude and have a comb blade shape.

  As shown in FIGS. 2 and 8, for example, three head units 30 (30A, 30B, and 30C) are provided on the carriage 31 on the flat plate in the recording medium conveyance direction (sub-scanning direction, orthogonal direction to the nozzle array arrangement). They are arranged adjacent to each other in the width direction (nozzle row arrangement direction, main scanning direction, Y direction) of the recording medium orthogonal to the (X direction), and are fixed by screws 36 while shifting the position in the X direction. For example, the head end 9a of the head unit 9Y-2 of the head unit 30B is placed in the space 50 between the head end 9a of the head unit 9Y-1 of the head unit 30A and the head end 9a of the head unit 9M-1. To do. With such an arrangement, the pitch P of the adjacent head units 30 can be smaller than the width W1 of the outer shape of the head portion 9 near the nozzle plate and equal to or smaller than the width W2 of the nozzle row 48. Thereby, for example, the gap in the Y direction between the nozzle rows 48 of the adjacent head portions 9K-2 and 9K-3 can be zero or partially overlapped. The other head unit 9 and the head plate 30 are similarly arranged.

  With this configuration, even if the distance between the head portions 9 arranged on the same head plate 33 is wide as B2, the size B4 in the X direction of the head of the entire apparatus is approximately K, C, M, and Y. The thickness of the eight head portions 9 corresponding to two sets of color sets can be set to the thickness in the X direction.

  When the four head portions 9K, 9C, 9M, and 9Y are fixed to the head plate 33, the positioning projection 31c that is the reference in the X direction of the head plate 33 and the positioning projections 31a and 31b that are the reference in the Y direction are respectively used. The nozzle position is detected by a microscope so that the X and direction positions of the nozzle row 48 of the head portion 9 become predetermined values, and the X and four head portions 9K, 9C, 9M, and 9Y with respect to the head plate 33 are detected. , Adjusting the position in the Y direction and the inclination θ. In this embodiment, the nozzle pitch is adjusted to be 1/10 or less of 84.6 μm, which is the discharge pitch to the recording medium. With this adjustment, it is not necessary to adjust each head portion 9 when the plurality of head plates 33 are attached to the carriage 31. For example, FIG. 10 shows the head portions 9K and 9C in an unadjusted state, and the head portions 9M and 9Y after adjustment.

  As shown in FIG. 11, the positioning protrusions 33 a and 33 b of the head plate 33 of the head unit 30 are respectively directed to the positioning protrusions 31 a and 31 b of the carriage 31, and the head unit 30 is positioned with respect to the carriage 31 in the Y direction. Further, the positioning projection 33 c of the head plate 33 of the head unit 30 is directed to the positioning projection 31 c of the carriage 31, whereby the head unit 30 is positioned with respect to the carriage 31 in the X direction. If necessary, the head plate 33 may be attached to the carriage 31 with its position and inclination adjusted.

  These three head units 30-1, 30-2, 30-3 are units having the same configuration. The carriage 31 and the head plate 33 are made of the same aluminum die-cast, and the thermal expansion is also the same, so that the carriage 31 and the head plate 33 are prevented from being deformed by the thermal expansion. The carriage 31 is fixed to the frame 32.

  As shown in FIG. 8, in these 12 head portions 9 in total, heads of the same color are alternately arranged along the Y direction. Further, when viewed from the X direction, both ends of the nozzle array 48 are arranged to coincide with each other or several nozzles overlap. The ejection timing for ejecting UV ink for each head can be adjusted. With such an arrangement, the head portions 9K-1, 9K-2, and 9K-3 are apparently heads having a nozzle row with a nozzle pitch of 300 dpi and a number of nozzles of about 3720 and a row length of 315 mm. An image is formed as if. By adjusting the ejection timing (delaying the ejection timing of the downstream nozzle row), one straight line can be formed on the recording medium 11 in the Y direction, which is the sub-scanning direction.

  Further, as shown in FIG. 7, the nozzle plate 46 in which the nozzle row 48 of each head portion 9 is formed is disposed to face the belt 24, and is about 1 mm away from the belt surface. It is arranged so that the distance from the recording medium 11 that is attracted and conveyed is about 1 mm.

  Next, image formation by the ink jet printer according to the first embodiment configured as described above will be described. FIG. 12 shows an electrical schematic block configuration of the ink jet printer according to the first embodiment.

  In this ink jet printer, when recording information on the recording medium 11 is input to the control unit 6, the head driving circuit 63, the light source driving circuit 65, and the conveyance driving mechanism circuit 67 are controlled by the control unit 6 in accordance with the recording information. . The recording information includes the size (length and width) of the recording medium 11, the medium type, the recorded image (characters, photographs, etc.), nozzle ejection information, ink type, outside air temperature / humidity, the number of printed sheets, and the like. Here, as the type of ink, UV ink that is cured by irradiation with ultraviolet light is used.

  The head unit 9 is driven from the control unit 6 via the head drive circuit 67, and discharge of UV ink droplets is controlled from the desired nozzle 47 at a desired timing. The head drive circuit 63 is provided for each of the 12 head portions 9. Further, the control unit 6 controls the light emission control of the ultraviolet LEDs 51 a and 51 b of the UV irradiation unit 52 at a desired timing by driving control of the light source driving circuit 65. The light source driving circuit 65 is provided in each of the ultraviolet LEDs 51a, 51b and the like, and a total of 24 light sources are used in this embodiment. The control unit 6 drives and controls the transport mechanism drive circuit 67 to drive the transport mechanism 2.

  First, the recording medium 11 taken in from the recording medium supply base 12 is fed by the paper feed roller 13, separated one by one by the separation roller 14, and the leading end portion contacts the registration roller pair 15. The sheet is fed again from the registration roller pair 15 at a timing. At this time, the inclination or the like of the recording medium 11 is corrected. Thereafter, the tip is nipped between the auxiliary roller 6 and the belt 24 and conveyed. The front end of the medium on the belt 24 is attracted to the belt 24 by the suction force (negative pressure) generated by the suction fan 20.

  The recording medium 11 nipped by the auxiliary roller 6 and the belt 24 passes below the head portion 9 while being adsorbed by the belt 24 by the negative pressure in the suction chamber 19. At that time, the position shift of the recording medium 11 is read by a line sensor (CCD) (not shown) arranged immediately after the auxiliary roller 6, and ink ejection from the nozzle 46 is controlled. Specifically, the timing at which the front end of the medium passes under each head unit 9 is predicted and calculated so that the ejection start timing is matched.

  Then, after reaching the lower portion of the head portion 9K, the timings at 9C, 9M, and 9Y are sequentially predicted on the recording medium 11 to be conveyed, and droplets of UV ink are ejected from each head according to the prediction results. The Thereafter, the UV light 53 on the recording medium 11 being conveyed is irradiated with the UV light 53 by the light irradiation unit 50 arranged on the downstream side of the head unit 9K, the UV ink is cured, and the downstream head unit 9C is further sequentially formed. , 9M, 9Y to form an image by discharging and curing UV ink. The recording medium 11 on which the image has been formed is discharged by a discharge roller pair 16 and stored in a discharge tray 17.

  In the present embodiment, one UV light irradiation unit 50 that irradiates UV light for curing the UV ink is integrally provided on the downstream side surface of each head unit 9. In this embodiment, one UV light irradiation unit 50 is composed of two ultraviolet LEDs 51a and 51b as light sources, and is responsible for curing UV ink ejected by an integrated upstream head. Similarly, the UV light irradiation unit 50 is in charge of curing the UV ink ejected by the upstream head even if it is a separate body. Further, the same number of light source driving circuits 65 as the light sources are provided, and the light sources can be individually controlled to emit light.

  For this reason, the ink jet printer of this embodiment has a configuration in which two light sources are arranged corresponding to one head unit 9, and a total of 24 light sources can independently control light emission. Such a configuration enables flexible UV light irradiation according to the image recording form. That is, each head unit 9 is controlled to discharge for each nozzle based on the recording information, and each ultraviolet LED 51a, 51b is controlled to emit light based on the recording information. The UV light irradiation unit 50 can be controlled to emit light only when discharged from the nozzle corresponding to the ultraviolet LED 51a, 51b in charge or when the discharged UV ink is conveyed under the UV light irradiation unit 50.

  For example, when UV ink is ejected from only the black head portion 9K in black and white printing, only the light source 64 disposed in the head portion 9K needs to emit light. Moreover, it is only necessary when the irradiation is discharged. In this case, the power consumption and heat generation of the UV light irradiation unit 50 are about ¼ compared to the case where all the light sources 64 emit light.

  FIG. 7 shows UV light irradiation in the case where there is no discharge of UV ink droplets from the head portions 9K-3 and 9Y-3 and there is discharge from the head portion 9C-3. Here, the solid line of the UV light 53 indicates that irradiation is performed, and the two-dot chain line indicates that irradiation is not performed.

In this example, since no liquid droplet was ejected from the head unit 9K-3, there was no UV light irradiation from the UV light irradiation unit 50 in charge of the head unit 9K-3. The UV light 53 is irradiated from the UV light irradiation unit 50 in charge of the head portion 9C-3. Of course, the ejection and the UV light irradiation may be performed not simultaneously, but when the ejected UV ink is conveyed within the irradiation range of the corresponding UV light irradiation unit 50.
FIG. 6 shows an example in which UV ink is ejected only from the left side nozzle row 48a and no UV ink is ejected from the right side nozzle row 48b among the nozzle rows 48 of one head unit 9. In this case, only the ultraviolet LED 51a that irradiates the discharge range of the nozzle row 48a to be discharged emits light, and the ultraviolet LED 51b corresponding to the other discharge range does not emit light. In this case, the power consumption and heat generation of the UV light irradiation unit 50 are at least ½.

  Further, since an ultraviolet LED is used as the light source, the response of the amount of light to be irradiated is much faster than, for example, a mercury lamp, and only a desired ultraviolet LED responsible for curing the UV ink ejected onto the recording medium 11 is used. What is necessary is just to irradiate UV light.

  As described above, according to the present embodiment, at least one UV light irradiation unit is directly applied to each head having one nozzle row so that the UV ink discharged from the nozzle row is cured. (Light source) is provided. Thus, if these heads are arranged on the head plate, the UV light irradiation unit is also arranged at the same time. Therefore, the arrangement of the head and the UV light irradiation unit is easy, and it is not necessary to provide a clearance between the UV light irradiation unit and the head, so that the size can be reduced. Further, even if the recording width (printing width) specification of the ink jet printer changes, for example, it is only necessary to arrange two head units so that recording can be performed even with a recording width of 210 mm. There is no need to newly design the light irradiating part, it is possible to flexibly cope with specification changes, and manufacturing is also easy.

  In addition, since a large number of UV light irradiation units are arranged corresponding to each head, and a plurality of UV light irradiation units are configured to correspond to one nozzle row, the nozzles of the head corresponding to the recording information are used. Only when a droplet of UV ink is ejected, UV light may be irradiated from the UV light irradiation unit in charge. Thereby, the power consumption and heat generation of the UV light irradiation unit can be greatly reduced.

  Further, since a plurality of UV light irradiation units are arranged so as to be in charge of the nozzle row of one head, UV corresponding to only a part of the nozzles from which the UV ink is ejected from the corresponding nozzles according to the recording information. What is necessary is just to irradiate UV light from a light irradiation part. For this reason, the power consumption and heat generation of the UV light irradiation unit can be reduced. Since the UV LED is used as the light source of the UV light irradiation unit, the light emission response is good and the irradiation is performed only when it is ejected from the nozzle in charge, so that the power consumption and heat generation of the UV light irradiation unit are reduced. be able to.

  In addition, the irradiation area of the light irradiated from the UV light irradiation unit is formed in an oblong shape on the recording medium, and is elongated in the nozzle array direction to change the medium transport direction (the relative movement direction of the nozzle array and the recording medium). Shortened. As a result, the spacing between the heads in the recording medium conveyance direction can be reduced.

  The irradiation area of the UV light irradiated from the UV light irradiation section was shaped to be an elliptical shape on the recording medium, and the light in the head direction adjacently arranged in the transport direction was projected onto the recording medium in a condensed state. For this reason, most of the reflected light from the recording medium is condensed as shown in FIG. 7, and the amount of light directed to the adjacent head is reduced. As a result, it is possible to prevent the nozzles of adjacent heads from being irradiated with ultraviolet light and causing nozzle clogging. Furthermore, although the ultraviolet light in the nozzle row direction, which is the main scanning direction, diverges in an elliptical shape as shown in FIG. 8, no problem occurs because the nozzles of other heads are not adjacent in the nozzle row direction.

In addition, since the cumulative amount of ultraviolet light applied to the recording medium for curing the UV ink is small, it is possible to reduce the occurrence of deterioration, deterioration, discoloration, and the like of the recording medium due to the ultraviolet light.
By arranging the heads at an interval, the ends become comb blades, and the heads arranged next to each other are fitted in the space between them. Yes. As a result, the length of the entire head row (carriage) in the transport direction can be suppressed to the length of one head unit plus the thickness of one head unit, thereby realizing downsizing.

  Further, the four color heads are fixed to the head plate to constitute an integrated unit. For this reason, it is possible to flexibly cope with various recording widths only by increasing / decreasing the same head unit, and the specification can be easily changed without changing the design. For example, in this embodiment, since the width of the nozzle row of one head is 105 mm and three head units are used, the recording width can be 315 mm, and when cut paper is used. Can record up to size A3 without moving the head in the main scanning direction. When two head units are used, the print width is 210 mm, and recording up to size A4 can be supported. When one is used, the print width is 105 mm and can be recorded on size A6 or a postcard.

  Further, a configuration in which four or more heads are arranged can realize a wider recording range. In this way, it is possible to construct a nozzle array that realizes various desired recording widths by arranging the desired number using the same head unit, and at the same time, a UV light irradiation unit is added as the number of heads increases and decreases. Therefore, an image recording apparatus such as an ink jet printer equipped with a droplet discharge head unit having various specifications can be easily and inexpensively manufactured.

Next, a modification of the above-described first embodiment will be described.
In the above-described embodiment, an inkjet head using a piezoelectric element is used. However, any other head unit having a nozzle array in which a plurality of nozzles are arranged, such as a bubble jet method, can be easily applied. is there.

  In the first embodiment, a drive circuit is provided for each UV light irradiation unit and can be individually controlled. That is, when the number of drive circuits is large and the control becomes complicated, the three heads constituting one color are formed for each head or for each head unit having four nozzles having a plurality of nozzle rows. You may make it control the light source corresponding to these collectively.

  When the UV ink is not ejected from the UV light irradiation unit or the nozzle in charge, the UV light irradiation may not be performed or the light amount may be reduced. When the light is emitted with the light amount reduced, the response is improved by increasing the light amount to a desired light amount in a short time, which is effective for high-speed recording.

In the embodiment, an ultraviolet LED is used for the UV light irradiation unit serving as a light source, but the present invention can also be realized by using a laser diode (LD). There is no particular limitation as long as it is a part that can be mounted on the head and can irradiate with a wavelength and intensity suitable for curing the photocurable ink to be used. Also, the types of objective lenses are not limited to those described in the embodiments. Further, the number of light sources is not limited to two and may be one or more than two.
As a recording medium used in this apparatus, cut paper is described as an example, but roll paper may be used.
The head is an example of a fixed head that does not move in the main scanning direction, but can also be applied to a scanning head. For example, an image may be formed by rotating the carriage 90 degrees around the Z axis and moving the carriage in the Y direction, which is the main scanning direction.

  The applied head for ejecting droplets of UV ink is not limited to an inkjet printer, but a printing device such as a copying machine or a facsimile for performing recording by ejecting droplets onto a recording medium, or a small amount of adhesive. Any head can be easily applied as long as it is a droplet discharge head used for discharging a small amount of droplets in an apparatus, an LCD color filter manufacturing apparatus, or the like.

    The accumulated light amount by the light source corresponding to each nozzle may be cured to such an extent that it does not bleed with the UV ink ejected from the downstream head, and after ejection from the last nozzle (head portion 9Y in this embodiment), A light irradiation device for complete curing may be added.

Next, a second embodiment will be described with reference to FIGS.
In addition, about the structure part of this embodiment, the same referential mark is attached | subjected to the site | part equivalent to the structure part demonstrated in 1st Embodiment mentioned above, and the description is abbreviate | omitted.

  In the second embodiment, as shown in FIG. 13, UV light is provided between four nozzle rows 81K, 81C, 81M, 81Y corresponding to the nozzle rows of the heads K, C, M, Y of each color. The integrated head unit 80 housed in one case is constructed so that the irradiation units are arranged alternately. That is, five UV irradiation units 82-1, 82-2, 82-3, and 82-4, which are UV light irradiation units, are arranged adjacent to these four nozzle rows, respectively. .

  As shown in FIG. 14, when the recording medium 11 relatively moves from the nozzle row 81K side of the head unit 80, the UV irradiation unit 82- is applied to the four nozzle rows 81K, 81C, 81M, 81Y. 2, 82-3, 82-4, and 82-5 correspond to each other. On the other hand, when the recording medium 11 moves relatively from the nozzle row 81Y side of the head unit 80, the UV irradiation units 82-1 and 82-1 are applied to the four nozzle rows 81K, 81C, 81M, and 81Y. 82-2, 82-3, and 82-4 correspond to each other.

  Since the UV irradiation units are arranged on both sides of the four heads as described above, for example, the head unit 80 is moved back and forth in the main scanning direction of the recording medium 11 as in a conventional scanning carriage, and a droplet of UV ink is used. It is also possible to form an image by discharging the ink.

  In the present embodiment, as shown in FIG. 13, the UV irradiation unit 82 includes a light source unit 83 and a lens 84. In the light source unit 83, a plurality of light emitting chips 83a of ultraviolet LEDs as light sources are disposed on a substrate 83b. A light emission drive circuit is provided for each light emitting chip 83a, and is configured to be able to individually control light emission. For example, a cylindrical lens 84 is fixed to the upper portion.

According to the configuration of the present embodiment, the same operations and effects as those of the first embodiment described above can be obtained.
Furthermore, since the light emission of the light emitting chip 83a is individually controlled, it is only necessary to emit light when UV ink is ejected from the nozzle in charge. For example, according to FIG. 14, when the nozzles 81K, 81C, and 81Y discharge the UV ink, the UV irradiation units 82-1 and 82-2 provided adjacent to the downstream side thereof. 82-4 emits light.

  FIG. 15 shows a state of the head as viewed from the carrying direction. In a state where both sides of one nozzle row are ejecting UV ink, the ink is ejected in the downstream UV irradiation unit. Curing is performed by the light-emitting chip facing the both side portions of the recording medium emitting light.

  In the present embodiment, a plurality of LED light emitting chips serving as light sources are configured as a one-row array. For this reason, light emission control can be performed more finely, and power consumption and heat generation can be further reduced. Further, the light source (UV irradiation unit 82) can be arranged closer to the recording medium, the efficiency is improved, the UV irradiation unit is further reduced in size and brightness, and as a result, the head unit can also be reduced in size. .

  In each of the above-described embodiments, the example in which the inkjet printer uses UV (ultraviolet) ink has been described. However, the present invention is not limited to this, and other infrared, visible light, electron beam, or X Ink that cures when exposed to light in a broad sense, such as lines, may be used, and the UV light irradiator and its light source are particularly limited as long as they are light sources that irradiate light necessary for curing the UV ink used. is not.

An example of a schematic configuration of an image recording apparatus according to the first embodiment of the present invention will be shown and described. It is a figure which shows the example of a mechanism of the image recording device which concerns on 1st Embodiment. It is a figure which shows the structural example of the head in 1st Embodiment. It is a figure which shows the structural example of the head in 1st Embodiment. It is a figure which shows the assembly structure of the head in 1st Embodiment. It is a figure which shows ink discharge and light irradiation by the structure which looked at the head unit of 1st Embodiment from the main scanning direction. It is a figure which shows UV ink discharge and light irradiation by the structure which looked at the head unit in 1st Embodiment from the subscanning direction. It is a figure which shows the example of arrangement | positioning of the head unit in the carriage of 1st Embodiment. It is a figure for demonstrating the assembly structure of the head unit in 1st Embodiment. It is a figure for demonstrating the position shift of the head unit in 1st Embodiment. It is a figure for demonstrating the structure which attaches a head unit to the carriage in 1st Embodiment. It is a figure which shows the electrical schematic block structure in 1st Embodiment. It is a figure which shows the structural example of the head unit in 2nd Embodiment. It is a figure which shows UV ink discharge and light irradiation by the structure which looked at the head unit of 2nd Embodiment from the main scanning direction. It is a figure which shows UV ink discharge and light irradiation by the structure which looked at the head unit in 2nd Embodiment from the subscanning direction. It is a figure which shows the 1st example of the image recording apparatus using the conventional UV ink. It is a figure which shows the 2nd example of the image recording apparatus using the conventional UV ink.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Medium supply discharge mechanism, 2 ... Conveyance mechanism, 3 ... Image formation mechanism, 4 ... Maintenance mechanism, 5 ... UV ink supply accommodation mechanism, 6 ... Control apparatus, 11 ... Recording medium, 12 ... Recording medium supply stand, 13 ... Paper feed roller, 14 ... Separation roller, 15 ... Registration roller pair, 16 ... Paper discharge roller pair, 17 ... Paper discharge tray, 18 ... Belt platen unit, 19 ... Suction chamber, 20 ... Suction fan, 21 ... Drive roller, 23 ... driven roller, 22 ... tension roller, 24 ... belt, 25 ... platen, 26 ... bottle, 27 ... sub tank, 28 ... suction pump, 29 ... waste liquid bottle, 30 ... head unit, 31 ... carriage, 32 ... frame 32, 9K, 9C, 9M, 9Y ... head.

Claims (19)

A droplet discharge head having a nozzle for discharging a photocurable ink that is cured by light irradiation on the recording medium;
A light irradiation unit for irradiating light to the photocurable ink discharged to the recording medium;
A scanning mechanism that changes a relative position of the recording medium and the droplet discharge head;
The liquid droplet ejection head ejects photocurable ink based on ejection information, and the light irradiation unit controls the amount of irradiation light in relation to the ejection information. In the image recording device,
The image recording apparatus according to claim 1, wherein the light irradiation unit is provided with a plurality of light sources. In the image recording device,
2. The image recording according to claim 1, wherein a plurality of the droplet discharge heads are provided, and an irradiation light amount corresponding to each of the plurality of droplet discharge heads is controlled in relation to the discharge information. apparatus. In the image recording device,
2. The droplet discharge head is provided for each of a plurality of colors of the photocurable ink, and an irradiation light amount corresponding to each color is controlled in relation to the discharge information. Image recording device. In the image recording device,
The droplet discharge head has a plurality of nozzles, and controls the amount of light emitted from the light irradiation unit corresponding to the nozzle portion that discharges the photocurable ink in relation to the discharge information. The image recording apparatus according to claim 1, wherein: In the image recording device,
The image recording apparatus according to claim 5, wherein there are a plurality of light sources of an irradiation unit corresponding to one droplet discharge head. In the image recording device,
The image recording apparatus according to claim 1, wherein the light irradiation unit is disposed in the droplet discharge head. In the image recording device,
The image recording apparatus according to claim 1, wherein the light irradiation unit is a laser diode (LD) or a light emitting diode (LED). In the image recording device,
The image recording apparatus according to claim 8, wherein the light irradiation unit includes a plurality of light sources arranged in an array. In the image recording device,
The image recording apparatus according to claim 1, wherein the nozzle is a plurality of nozzle rows, and the light irradiation unit is disposed between the plurality of nozzle rows. In the image recording device,
The image recording apparatus according to claim 1, further comprising an optical system that shapes light from the light irradiation unit. In the image recording device,
The image recording apparatus according to claim 1, wherein light from the light irradiation unit is projected on a medium in a condensed state. A droplet discharge head having a nozzle for discharging a photocurable ink that is cured by light irradiation on a recording medium,
A droplet discharge head comprising a light irradiation light source for irradiating light to the photocurable ink discharged onto the medium, wherein the light irradiation light source is integrated with the droplet discharge head. In the droplet discharge head,
14. The liquid droplet ejection head according to claim 13, wherein the liquid droplet ejection head ejects photocurable ink based on ejection information, and the light source is controlled in light quantity in relation to the ejection information. . A droplet discharge head having a nozzle row composed of a plurality of nozzles that discharges a photocurable ink that is cured by irradiation of light onto a recording medium to be conveyed;
A light irradiation unit that is integrally provided on the downstream side in the transport direction of the droplet discharge head and that irradiates the light to the photocurable ink discharged to the recording medium;
A scanning mechanism for changing a relative position of the recording medium and the droplet discharge head,
After the droplet discharge head discharges the photocurable ink based on the input recording information, the light irradiation unit has the presence and absence of the photocurable ink landed on the recording medium according to the prerecorded information. An image recording apparatus that controls the amount of light emitted according to information. In the image recording apparatus,
The droplet discharge head and the light irradiation unit are integrally attached to a side surface on the downstream side in the transport direction of the droplet discharge head so that at least the light emitting unit of the light irradiation unit is exposed to form one unit. Configure the head part,
The image recording apparatus according to claim 15, wherein the nozzle row irradiates the landing area of the UV ink landed on the recording medium. In the image recording apparatus,
The image forming apparatus according to claim 16, wherein a plurality of light sources of the light irradiation unit are arranged along a row direction of the nozzle row of the head unit. In the image recording apparatus,
A plurality of the head portions are arranged along the width direction of the recording medium or the conveyance direction of the recording medium, and the irradiation light quantity corresponding to each of the plurality of droplet discharge heads is controlled in relation to the recording information. The image recording apparatus according to claim 16, wherein: In the image recording apparatus,
A plurality of the head portions are arranged along the conveyance direction of the recording medium so that the ink row is in a direction perpendicular to the conveyance direction, thereby constituting a head unit.
The head units are arranged so that the end portions of the head portions of other head units adjacent in the orthogonal direction enter into the space between the end portions of the head portions arranged so as to be alternately fitted. The image recording apparatus according to claim 18.

Images