JP2005199635A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer using an ultraviolet-curable ink wherein an ultraviolet light from an ultraviolet radiation device is not allowed to arrive at an inkjet head section, thereby preventing a nozzle or the like from being clogged. <P>SOLUTION: There is disclosed the inkjet printer wherein an inkjet head and an ultraviolet radiation section are sequentially provided on a recording medium 19 which is attracted to be fixed to a rotary cylindrical printing drum 1. A plurality of grooves 14 are formed on the cylindrical printing drum 1 along a circumferential direction. A movable attraction member 17 for attracting the rear end section of the recording medium and a light shielding plate 20 provided to the downstream thereof are provided to the printing drum 1 so as to be fitted to the grooves 14. The printing drum 1 has an opening section for opening or closing a pawl member 22 for grasping the tip of the recording medium. Each of the gap between the end face of the groove 14 and the attraction member 17 and the gap between the end face and the light shielding plate 20 is made to be not greater than 1 mm and the opening section is covered with a light shielding cover 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an inkjet printer that can reproduce a high-definition image using an ultraviolet curable ink, and more particularly, to an inkjet printer capable of industrial high-speed printing.

  In recent years, inkjet printers are inexpensive and can form images with a simple mechanism, so they have been applied to various printing fields such as photography, various printing, micropatterning such as color filters, etc. An ink jet printer or the like that can perform printing in the width direction of a recording medium such as paper by moving the ink jet head and can perform high-definition printing by conveying the recording medium is also commercially available.

  On the other hand, as an inkjet printer for industrial use, a printer that performs printing at high speed by fixing the position of an inkjet head during printing, adsorbing the recording medium to a cylinder and transporting the recording medium has been developed. In order to enable printing on a wide variety of recording media, such an ink jet printer uses an ultraviolet curable ink as the ink, irradiates the ultraviolet rays immediately after printing, and instantaneously cures the ink, thereby forming the ink on the recording medium. Has been established. The ultraviolet curable ink jet method has attracted attention in recent years because it has a relatively low odor and is quick-drying compared to the solvent type ink jet method, and can be printed on a recording medium having no ink absorption (for example, Patent Document 1). reference.).

  In addition, there is a cylinder in which a cylinder printing cylinder for transporting a recording medium of an offset printing machine is used as a cylinder for transporting a recording medium of an ink jet printer (see, for example, Patent Document 2).

The above prior art documents are shown below.
JP-A-6-200204 Japanese Unexamined Patent Publication No. 7-24998

  However, when the recording medium transport cylinder of a printing machine such as an offset printing machine is used in an ink jet printing machine using ultraviolet curable ink, the following problems occur. That is, the cylinder-shaped printing cylinder for paper conveyance of the offset printing machine has a plurality of ribs on its circumference. Between the ribs, an adsorption member that adsorbs the bottom of the recording medium is provided so as to be movable with respect to the cylindrical printing cylinder. Since this recording medium bottom part adsorption | suction part respond | corresponds to each recording medium size, it can operate | move in the circumferential direction along the above-mentioned loose part. Therefore, a clearance of about 2 to 3 mm is provided between the end surface of the cylinder body of the cylinder-shaped printing cylinder and the block member including the recording medium bottom portion suction member, and the clearance is increased. Further, the cylinder-shaped printing cylinder has a claw member for gripping the leading end of the recording medium, and the front part of the claw member has a structure having an opening for reversing the recording medium and opening and closing the claw member. It has become.

When the cylinder-shaped printing cylinder configured as described above is used in an inkjet printing machine using ultraviolet-curable ink, the light from the ultraviolet irradiation section absorbs the end surface of the cylinder body of the cylinder-shaped printing cylinder and the bottom of the recording medium. Ultraviolet light is reflected in the direction of the inkjet head from the gap between the block containing the member and the opening of the front part of the claw member and into the metal part such as the shaft and glossy part embedded in the cylinder. Then, ultraviolet light leaks through the slit, and the ultraviolet curable ink located at the tip of the inkjet head is cured. That is, there is a problem that clogging of the inkjet head nozzle occurs. In other words, the problem is that the ultraviolet light from the ultraviolet irradiation device leaks to the inkjet head section, which is the printing section, for some reason, or the ultraviolet light is applied to the print head section depending on the internal structure of the cylindrical printing cylinder for paper conveyance. As a result, the ink is thickened on the print head nozzle surface, or the ultraviolet light reaches the inside of the nozzle and the ink is cured, resulting in ejection failure. In the worst case, pressure purge, suction purge, etc. Even if maintenance is performed, the print head may not be restored.

  The present invention has been made in view of such a problem, and the problem is that an ultraviolet light from the ultraviolet irradiation device is not applied to the inkjet printing cylinder so as not to reach the inkjet head. An object of the present invention is to provide an ink jet printer using an ultraviolet curable ink that can take measures against light shielding and prevent clogging of the ultraviolet curable ink.

  In order to achieve the above object in the present invention, first, in the invention of claim 1, a plurality of inkjet heads for discharging ultraviolet curable ink are provided, a rotating cylindrical printing cylinder, and ultraviolet curable ink are cured. In an inkjet printing machine having an ultraviolet irradiation part for making a cylinder-shaped printing cylinder is arranged so as to fit into the plurality of ribs, a cylinder body having a plurality of ribs along the circumferential direction of the cylinder, A block member including a recording medium bottom portion adsorbing member that is movable with respect to the cylinder body, a claw member that fixes the recording medium to the cylinder, grips and fixes the leading end of the recording medium, and is in the vicinity of the claw member An opening for opening and closing the claw member, and a gap between the cylinder body and the block member including the recording medium bottom portion adsorption member is 1 mm or less. Is obtained by the ink jet printer, characterized in that it.

  According to a second aspect of the present invention, there is provided the ink jet printing machine according to the first aspect, wherein an opening for opening and closing the claw member is covered with a light shielding cover.

  Since this invention is the above structure, there exist the following effects.

  That is, according to the first and second aspects of the present invention, the gap between the end surface of the groove of the cylindrical printing cylinder and the block member including the recording medium bottom portion adsorbing member that adsorbs the bottom portion of the recording medium. A gap of about 3 mm is set to 1 mm or less, and an opening for opening and closing the nail member at the front of the nail member that holds the tip of the recording medium is covered with a light-shielding cover on the cylinder-shaped printing cylinder. The ultraviolet light that reaches the light is shielded, and the ink of the nozzle plate, the nozzle opening, and the ultraviolet curable ink in the flow path are prevented from being cured by the ultraviolet irradiation, and the ink jet printer can be obtained.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing the entirety of an inkjet printer using the ultraviolet curable ink of the present invention, and FIG. 2 is an ink shed head unit constituting the inkjet printer using the ultraviolet curable ink of the present invention. It is a cross-sectional schematic diagram showing the periphery. As shown in FIGS. 1 and 2, the ink jet printer using the ultraviolet curable ink of the present invention is a recording medium which is fixed and fixed to the nail member 22 and the suction member 17 of the rotating cylindrical printing cylinder 1 and is conveyed. An ultraviolet curable ink having an inkjet head unit 2 composed of a plurality of inkjet heads 12 that eject ultraviolet curable ink and an ultraviolet irradiation unit 3 that cures the ejected ultraviolet curable ink is provided in order. This relates to the ink jet printer 100 used.

  FIG. 3 is a schematic explanatory view showing the cylindrical printing cylinder 1 which is a main part of the present invention as a plane. FIG. 4 is a schematic perspective view around the cylinder-shaped printing cylinder 1 for transporting the recording medium before countermeasures, and FIG. 5 is a schematic perspective view around the cylinder-shaped printing cylinder 1 for transporting the recording medium according to the first aspect of the invention. FIG. 6 is a schematic sectional view around the cylindrical printing cylinder 1 for conveying a recording medium according to the second aspect of the present invention.

  Around the cylinder-shaped printing cylinder 1 for transporting the recording medium before the countermeasure shown in FIG. 4, a gap of 2 to 3 mm is provided between the block member 15 including the adsorbing member 17 that adsorbs the bottom of the recording medium 19 and the cylinder body 16. In addition, since an opening (not shown) downstream of the claw member (not shown) at the upstream portion of the suction member 17 also covers a wide range, these portions are irradiated from an ultraviolet irradiator (not shown). The ultraviolet light is reflected on the components inside the cylindrical printing cylinder 1 and the ultraviolet light reaches the ink jet head. Especially when the size of the recording medium 19 made of, for example, paper is small, the paper bottom of the suction member 17 Since the upstream opening 18 from the side becomes large, the ultraviolet light leaks from this portion even while the recording medium 19 is being transported. As a result, the ink in the vicinity of the ink jet head unit and the ink existing inside the head nozzle are thickened, which causes ejection failure which is the biggest problem of ink jet printing.

  2 and 3, the cylindrical printing cylinder 1 has a claw member 22 for gripping the end of the recording medium 19, and the front part of the claw member 22 inverts the recording medium 19. In addition, since the opening 18 is provided to open and close the claw member 22, the ultraviolet light irradiated by the ultraviolet irradiator is reflected in the opening 18 minutes, and naturally the reflected ultraviolet light is also reflected. It could reach the inkjet head 12 and cause a phenomenon such as ejection failure as described above.

  Therefore, the invention according to claim 1 aims to reduce the amount of ultraviolet light reflected from the ultraviolet irradiation part to the metallic part such as the shaft embedded in the cylinder, the glossy part, and reaching the inkjet head part, In order to reduce the amount of ultraviolet light reaching the inkjet head, for example, as shown in FIG. 5, the block portion is covered with a light shielding plate 20 to reduce the clearance from the end surface of the cylinder body 16, and this light shielding plate 20 is placed upstream. The suction member 17 on the side is taken in and greatly extended to function as a shutter. The clearance between the light shielding plate 20 and the end face of the cylinder body 16 in FIG. There was no gap.

  In the invention according to claim 2, for example, as shown in FIGS. 3 and 6, the cylindrical printing cylinder 1 has a claw member 22 for gripping the end portion of the recording medium. There is an opening 18 for opening and closing the claw member 22 for inverting the recording medium, and the light shielding cover 21 covers the opening 18 to prevent ultraviolet light reflected from the opening 18. The fixing member 24 is used for attachment, and the light shielding cover 21 of the claw swing retracting portion of the claw member 22 is attached on the cylinder circumferential surface as much as possible. In the case of a large-sized recording medium, the light shielding plate 20 is configured to sink under the light shielding cover 21.

The light shielding effect was confirmed as follows by the above light shielding measures. That is, in order to confirm the light shielding effect, a commercially available UV label: TYPE-S ultra-high sensitivity (manufactured by NOF Corporation) is used, and this label is attached to 8 places below the inkjet head 12 using a jig. In addition, the arrival of ultraviolet light was confirmed. The irradiation time by the ultraviolet irradiation machine was all performed for 1 hour continuously. This ultraviolet irradiator HP-6 (manufactured by Fusion UV Systems) is used, and the type of ultraviolet lamp used is a D bulb (emission wavelength peak 350 to 380 nm) manufactured by the same company. The control output of the ultraviolet irradiator at the time of measurement was 100%, and irradiation was performed at the maximum output that the apparatus can have. Furthermore, the position of the UV irradiator was determined to be impossible to block light from the front position based on the test results at the front position of the UV irradiator fixing light seal. Irradiation was performed.

  When the above-mentioned improvements were made and the state of discoloration after irradiation for 1 hour with the UV label was confirmed, the discolored portion of the UV label that had been before the countermeasure was almost eliminated, and ultraviolet light shielding was almost realized. In this implementation, the continuous irradiation time is 1 hour. As a result, a partial discoloration is confirmed, but in actual operation, maintenance operations such as pressurization and suction are performed during printing at regular intervals. It was judged that there was no problem with this degree of discoloration.

  Further, since the recording medium is naturally conveyed by the cylinder during actual printing, the recording medium itself exhibits a light shielding effect. Therefore, this embodiment can be said to be the most severe condition for the inkjet head, and it can be said that the test result with the UV label in this state is good.

  According to the ink jet printer of the present invention, an excellent practical effect can be exhibited, for example, as a proofreading printer or a calendar store name printing printer.

1 is an overall view of an ink jet printer using an ultraviolet curable ink of the present invention. It is the schematic explanatory drawing which represented the cylinder-shaped printing cylinder circumference which comprises the inkjet printing machine using the ultraviolet curable ink of this invention in the cross section. It is explanatory drawing which represented the cylinder-shaped printing cylinder which comprises the inkjet printing machine using the ultraviolet curable ink of this invention as a plane. It is a perspective view for demonstrating the cylindrical printing cylinder which comprises the conventional inkjet printer. It is a perspective view for demonstrating the cylindrical printing cylinder which comprises the inkjet printing machine of this invention. It is a sectional side view for demonstrating the cylindrical printing cylinder which comprises the inkjet printing machine of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylinder-shaped printing cylinder 2 ... Inkjet head unit 12 ... Inkjet head 13 ... UV irradiation machine 14 ... Groove 15 ... Block member 16 ... Cylinder body 17 ... Adsorption member 18 ... Cylinder opening 19 ... Recording medium 20 ... Shading plate 21 ... Shading cover 22 ... Claw member 24 ... Shading cover fixing member

Claims (2)

  In an inkjet printing machine having a plurality of inkjet heads for discharging ultraviolet curable ink and having a rotating cylindrical printing cylinder and an ultraviolet irradiation unit for curing the ultraviolet curable ink, the cylindrical printing cylinder is a cylinder A cylinder main body having a plurality of ribs along a circumferential direction; and a block member including a recording medium bottom portion adsorbing member which is arranged to fit into the plurality of ribs and is movable with respect to the cylinder main body; A claw member that fixes the recording medium to the cylinder and grips, fixes, and transports the leading end of the recording medium, and an opening for opening and closing the claw member in the vicinity of the claw member, and the cylinder body and the bottom of the recording medium An ink jet printing machine, wherein a gap with a block member including a partial adsorption member is 1 mm or less. 2. The ink jet printer according to claim 1, wherein an opening for opening and closing the claw member is covered with a light shielding cover.

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