Flexographic ink feeding apparatus

Abstract: There is provided a flexographic ink feeding apparatus in which a part of a chamber into which ink is fed is defined by a blade mounting plate (19) and blades (23,26). The junction of the blade mounting plate (19) and the blade (23,26) is formed so as to make an obtuse angle.

Description: The present invention relates to an ink feeding apparatus in a flexographic press. FIG. 5 of the accompanying drawings shows schematically a conventional chamber doctor blade type ink feeding apparatus (hereinafter referred to simply as "ink feeding apparatus") in a flexographic press. In this ink feeding apparatus, a beam 2 is disposed so as to face the surface of an anilox roll 1. This beam 2 has a width approximately equal to the total length of the anilox roll 1. The beam 2 is provided with a blade mounting plate 3. The upper part of the blade mounting plate 3 is formed with an inclined face 3a extending rearward obliquely, and the lower part thereof is also formed with an inclined face 3b extending rearward obliquely. On the inclined faces 3a and 3b, a seal blade 4 and a doctor blade 5 are disposed. respectively. The tip ends of the seal blade 4 and doctor blade 5 are positioned close to or in contact with the surface of the anilox roll 1. The openings at both ends of a space defined by the blade mounting plate 3, seal blade 4, doctor blade 5, and anilox roll 1 are closed by side plates 6, 6. This space forms a chamber 7 into which ink is fed. On the other hand, a groove 2a is formed in the surface of the beam 2 on the side of the blade mounting plate 3, and the blade mounting plate 3 is formed with holes 3c which connect the groove 2a to the chamber 7. Further, the lower end portion of the blade mounting plate 3 is formed with a hole 3d, so that the chamber 7 is connected with an ink tube 8 via this hole 3d. In the conventional ink feeding apparatus configured as described above, ink is fed into the chamber 7 through the ink tube 8, the ink filled in the chamber 7 is applied onto the surface of the anilox roll 1, and the ink is scraped to a predetermined film thickness by the doctor blade 5, by which the film thickness of ink is controlled. For the above-described conventional ink feeding apparatus in a flexographic press, after the color is changed or the printing is finished, it is necessary to recover the ink in the chamber 7 and clean the chamber 7. To recover the ink and clean the chamber 7, the ink in the ink tube 8 is sucked by rotating a pump 9 in the reverse direction, cleaning water is supplied into the groove 2a in the beam 2, and further supplied into the chamber 7 from the groove 2a through the holes 3c to clean the interior of the chamber 7. After cleaning, the water is discharged through the ink tube 8 by using the pump 9. However, in the above described conventional ink feeding apparatus in a flexographic press, since the junctions of the blade mounting plate 3 and the seal blade 4 and doctor blade 5, which defines the chamber 7, that is, the comers of the chamber 7 make an acute angle, the ink having accumulated in the comer portions is not recovered at the time of ink recovery. Also, even if cleaning water is circulated at the time of cleaning, it is difficult for the water to flow into the comer portions, so that thorough cleaning cannot be performed. From DE-A-2971 8387, it is known that the acute angle can be replaced by an obtuse angle formed between the blade and a rigid sidewall of a blade-mounting housing, whereby to reduce the possibility of ink accumulating between the blade and the blade mounting plate. The present invention has been made to provide an alternative flexographic ink feeding apparatus that has the advantage of simplicity of construction whilst being capable of sufficiently performing the recovery of ink in a chamber and cleaning of the interior of the chamber. In accordance with the present invention, there is provided a flexographic ink feeding apparatus in which a part of a chamber into which ink is fed is defined by a blade mounting plate and at least one blade, with the junction of the blade mounting plate and said at least one blade being formed so as to make an obtuse angle, wherein a packing member is disposed at the junctions of said blade mounting plate and the or each blade, said obtuse angle being defined between the blade and a surface of the packing member. Since there is no acute-angled portion in the chamber, there is no portion where ink enters and accumulates, so that the recovery of ink in the chamber and cleaning of the interior of the chamber can be performed easily. Since the addition of the packing member eliminates the presence of an acute-angled portion in the chamber, the conventional parts can be used without being changed, so that an improved ink feeding apparatus can be realized at a low cost. Each packing member can be fixed to a plate, and the plate sandwiched between the blade and the blade mounting plate, by which the packing member is held. According to the ink feeding apparatus of this embodiment, the packing can be installed easily. Preferably, the packing members are made of sponge rubber. Since the packing members and the blade mounting plate are brought into contact with each other, ink does not enter the joining portions between them, so that the recovery of ink in the chamber and cleaning of the interior of the chamber can be performed more securely. As described above, in a flexographic ink feeding apparatus in accordance with the present invention, since there is no acute-angled portion in the chamber, that is, there is no portion where ink enters and accumulates, ink does not accumulate at the time of ink recovery, or the flow of clean water is not disturbed at the time of cleaning. Therefore, uncleaned portions do not remain, and the recovery of ink and cleaning can be performed easily, so that the productivity can be increased. Also, when the acute-angled portions in the chamber are eliminated by the addition of the packing members, the conventional parts can be used without being changed, so that an improved ink feeding apparatus can be realized at a low cost. Further, when the packing members are fixed to plates, and the plates are sandwiched between the blades and the blade mounting plate, by which the packing members are held, the packing can be installed easily. Also, when the packing members are made of sponge rubber, since the packing members and the blade mounting plate are brought into contact with each other, ink does not enter the joining portions between them, so that the recovery of ink and cleaning can be performed more securely. The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings, in which:- FIG. 1 is a longitudinal sectional view schematically showing a flexographic ink feeding apparatus in accordance with an embodiment of the present invention; FIG. 2 is a front view schematically showing an ink feeding apparatus excluding an anilox roll in a flexographic ink feeding apparatus in accordance with an embodiment of the present invention; FIG. 3 is a longitudinal sectional view enlargedly showing a principal portion of the ink feeding apparatus shown in FIG. 1; FIG. 4 is a front view showing a construction in which a tip end of an ink tube is attached; and FIG. 5 is a longitudinal sectional view schematically showing a conventional flexographic ink feeding apparatus. The present invention will now be described in detail with reference to an embodiment shown in the drawings. FIG. 1 is a longitudinal sectional view schematically showing a flexographic ink feeding apparatus in accordance with an embodiment of the present invention, and FIG. 2 is a front view schematically showing an ink feeding apparatus excluding an anilox roll. In this ink feeding apparatus 10, an anilox roll 12 is disposed between press frames 11, 11, and is supported on them so as to be rotatable. In parallel with the axis of the anilox roll 12, a beam 13 having a rectangular cross section is arranged, and side plates 14, 14 are fixed to the both ends of the beam 13. The lower part of the side plate 14 is rotatably supported on the frame 11 with a pin 15. Also, an air cylinder 16 is disposed on the frame 11, and a piston rod 16a of the air cylinder 16 is connected to the upper part of the side plate 14. On the surface of the beam 13 on the side of the anilox roll 12 is disposed a block 17 having a length corresponding to the substantially total length of the anilox roll 12. A groove 18 is formed in the surface of the block 17 on the side of the anilox roll 12 over substantially the total length of the block 17, and a blade mounting plate 19 is fixed onto the surface of the block 17 on the side of the anilox roll 12 so as to cover the groove 18. A conduit 20 is formed by the groove 18 and the blade mounting plate 19, and communicates with a chamber, described later, via holes 21 formed in the blade mounting plate 19. As shown enlargedly in FIG. 3, the blade mounting plate 19 has a vertical wall 19a which covers the groove 18, horizontal walls 19b and 19c disposed so as to cover the upper and lower parts of the block 17, respectively, and inclined walls 19d and 19e formed obliquely at the boundary of the horizontal walls 19b and 19c. A base end portion of a seal blade 23 is fastened to the inclined wall 19d via a press plate 24 with bolts 22, and the tip end of the seal blade 23 is positioned close to the surface of the anilox roll 12 (see FIG. 1). Also, a base end portion of a doctor blade 26 is fastened to the inclined wall 19e via a press plate 27 with bolts 25, and the tip end of the doctor blade 26 is positioned close to the surface of the anilox roll 12 (see FIG. 1). Also, end plates 28, 28 are disposed at both side ends of the blade mounting plate 19 to close side openings defined by the blade mounting plate 19, seal blade 23, and doctor blade 26. The end plate 28 has a seal member 28a bonded on the side of the anilox roll 12, which seals a gap between the end plate 28 and the anilox roll 12. Further, a packing member 30, made of sponge rubber, is disposed in an acute-angled corner portion 29 defined by the seal blade 23 and the vertical wall 19a of the blade mounting plate 19, and a plastic mounting plate 31 is bonded to the packing member 30. The packing member 30 is arranged in a space by fastening the mounting plate 31 between the seal blade 23 and the inclined wall 19d of blade mounting plate 19. The packing member 30 serves to eliminate the effect of the acute angle of the corner portion 29. By a free end face 30a of the packing member 30, a junction of the free end face 30a and the vertical wall 19a of the blade mounting plate 19 and a junction of the free end face 30a and the seal blade 24 are formed so as to make an obtuse angle. Also, a packing member 33, made of sponge rubber, is disposed in an acute-angled corner portion 32 defined by the doctor blade 26 and the vertical wall 19a of the blade mounting plate 19, and a plastic mounting plate 34 is bonded to the packing member 33. The packing member 33 is arranged in a space by fastening the mounting plate 34 between the doctor blade 26 and the inclined wall 19e of blade mounting plate 19. The packing member 33 serves to eliminate the effect of the acute angle of the corner portion 32. By a free end face 33a of the packing member 33, a junction of the free end face 33a and the vertical wall 19a of the blade mounting plate 19 and a junction of the free end face 33a and the doctor blade 26 are formed so as to make an obtuse angle. A chamber 35 into which ink is fed is defined by the blade mounting plate 19, seal blade 23, doctor blade 26, packing members 30 and 33, end plates 28, 28, and the anilox roll 12. At the lower part of the blade mounting plate 19 defining this chamber 35, one end of an ink tube 36 is inserted and fixed. In order to position a tip end opening 36a of the ink tube 36 at the lowermost portion of the chamber 35, a notch 33a is formed in the upper surface of the packing member 33, and the tip end opening 36a of the ink tube 36 is disposed at the bottom of the notch 33a as shown in FIG. 4. In the ink feeding apparatus 10 thus configured, ink is fed into the chamber 35 via the ink tuba 36 by using a pump 37. This ink is applied to the surface of the rotating anilox roll 12, and the thickness of the applied ink is controlled to a predetermined value by the doctor blade 26. Also, in this ink feeding apparatus 10, at the time of ink change or cleaning of the interior of the chamber 35, the ink in the chamber 35 is discharged by rotating the pump 37 in the reverse direction, and clean water is supplied into the chamber 35 through the conduit 20 and the holes 21 in the blade mounting plate 19 by driving a pump 38. Thereby, the cleaning water circulates through the chamber 35 to clean the interior thereof. After cleaning, the cleaning water is discharged to the outside through the ink tube 36 by using the pump 37.

Claims: A flexographic ink feeding apparatus in which a part of a chamber into which ink is fed is defined by a blade mounting plate (19) and at least one blade (23;26), with the junction of said blade mounting plate (19) and said at least one blade being formed so as to make an obtuse angle, characterised in that a packing member (30; 33) is disposed at the junction of said blade mounting plate (19) and the or each blade (23; 26), said obtuse angle being defined between the blade (23; 26) and a surface of the packing member (30; 33). A flexographic ink feeding apparatus according to claim 1, wherein said packing member (30; 33) is fixed to a plate (31; 34), and said plate (31; 34) is sandwiched between said blade (23; 26) and said blade mounting plate, by which said packing member is held. A flexographic ink feeding apparatus according to claim 1 or 2, wherein said packing member (30; 33) is made of sponge rubber.

Inventors: NIUCHI KUNIO, SHIMOHATSUBO MAKOTO, NIUCHI, KUNIO, SHIMOHATSUBO, MAKOTO, Niuchi, Kunio, c/o Mihara Mach. Works, Shimohatsubo, Makoto, c/o Mihara Mach. Works
Applicants: MITSUBISHI HEAVY IND LTD, MITSUBISHI HEAVY INDUSTRIES, LTD.
Application year: 1999
Main classification: B41F31
IPC codes: B41F31