Furnisher roll

Abstract

To provide a furnisher roll that can prevent a coating liquid such as an ink adhered to an outer peripheral surface thereof from splashing.SOLUTION: A spiral groove 4, in which an ink (coating liquid) 3 flows to an axial direction center side in association with rotation with a gravure plate cylinder 1, is formed in a prescribed range from an axial direction end face at both ends in an axial direction of an outer peripheral surface of a furnisher roll 2. By this, outflow of the ink 3 from the axial direction end face of the finisher roll 2 is suppressed and a film thickness of the ink 3 at both ends in the axial direction of the outer peripheral surface is ensured, and surface tension of the ink 3 at both ends in the axial direction of the outer peripheral surface is ensured, and therefore, ink droplets adhered to the outer peripheral surface can be prevented from splashing.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a furnisher roll, and more particularly to a furnisher roll that supplies a coating liquid such as ink by rotating and contacting a rotating gravure plate cylinder. [Background technology]

[0002] An example of such a furnisher roll is described in Patent Document 1 below. In this furnisher roll, one or more grooves are formed on the cylindrical outer peripheral surface that rotates in contact with the gravure plate cylinder, and a spiral groove is disclosed as an example of the groove. It is understood that the grooves are provided continuously over the entire axial length of the cylindrical outer peripheral surface of the furnisher roll. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 63-39539 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-305394 Summary of the Invention [Problem to be solved by the invention]

[0004] A furnisher roll supplies ink to a gravure plate cylinder used in gravure printing. However, conventional furnisher rolls have a problem in that ink adhering to the outer peripheral surface scatters as droplets and adheres to the printing material, such as paper. The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a furnisher roll that can prevent coating liquid such as ink adhering to the outer peripheral surface from scattering. [Means for solving the problem]

[0005] In order to achieve the above object, one aspect of the furnisher roll of the present invention is a furnisher roll having a cylindrical outer peripheral surface, which rotates while contacting a rotating gravure plate cylinder to supply a coating liquid to the gravure plate cylinder, and in this case, spiral grooves are formed within a predetermined range from the axial end faces at both axial ends of the outer peripheral surface, through which the coating liquid flows toward the axial center as the roll rotates with the gravure plate cylinder. [Effects of the Invention]

[0006] According to the present invention, it is possible to prevent the scattering of coating liquid such as ink adhering to the outer peripheral surface. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a front view showing one embodiment of a furnisher roll of the present invention. FIG. [Figure 2] FIG. 2 is an explanatory diagram of the function of the furnisher roll of FIG. 1. [Figure 3] FIG. 10 is an explanatory diagram of the operation of a conventional furnisher roll. [Figure 4] FIG. 2 is an explanatory diagram of ink flow grooves in the furnisher roll of FIG. 1. [Figure 5] FIG. 5 is a detailed explanatory view of the ink flow groove in FIG. 4. [Figure 6] FIG. 10 is an explanatory diagram of ink flow grooves of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the furnisher roll of the present invention will be described in detail with reference to the drawings. The embodiments shown below are merely examples of configurations and methods for embodying the technical concept of the present invention, and the technical concept of the present invention is not limited to the following embodiments in terms of the materials, shapes, structures, arrangements, etc. of the components. Furthermore, the drawings are schematic. Therefore, it should be noted that the relationship and ratio between thickness and planar dimensions differ from the actual ones, and the drawings also contain portions where the relationship and ratio of dimensions differ from each other.

[0009] The finisher roll 2 shown in FIG. 1 has a cylindrical outer peripheral surface, similar to the finisher roll described in Patent Document 1, and is disposed below the gravure plate cylinder 1. The axial direction of the finisher roll 2 is parallel to the axial direction of the gravure plate cylinder 1, and the cylindrical outer peripheral surface of the finisher roll 2 abuts (contacts) against the cylindrical outer peripheral surface of the gravure plate cylinder 1 under a predetermined pressure. The outer peripheral surface of the finisher roll 2 is made of an elastic material such as rubber, and generally, the lower part of the finisher roll 2 is immersed in a reservoir of ink (coating liquid) 3, and by rotating the finisher roll 2, the ink 3 adhered to its outer peripheral surface is supplied to the outer peripheral surface of the gravure plate cylinder 1, thereby performing gravure printing. The finisher roll 2 itself and the gravure plate cylinder 1 themselves are similar to existing ones.

[0010] In this embodiment, spiral grooves 4 are provided at both axial ends of the cylindrical outer peripheral surface of the finisher roll 2 within a predetermined range from each axial end surface. As described above, ink 3 is attached to the outer peripheral surface of the finisher roll 2. The attached ink 3 flows into the spiral grooves 4 due to the fluidity of the ink itself and the contact rotation with the gravure plate cylinder 1 (it also adheres to the ink reservoir). The spiral grooves 4 allow the ink 3 to flow toward the axial center of the outer peripheral surface of the finisher roll 2 as the finisher roll 2 rotates with the gravure plate cylinder 1. A familiar example of a spiral groove 4 is a screw, so the following explanation will use the specifications and names of the screw grooves of a screw (male screw). The amount of axial movement (leading) of the screw groove per one rotation is called the lead, and the angle between the screw groove on the outer peripheral surface of the screw and the direction perpendicular to the axis is called the lead angle. Furthermore, the number of thread grooves formed in one circumferential turn around the outer peripheral surface of the screw is called the number of threads, and is counted as 1 thread, 2 threads, etc. In the following explanation, the thread groove will be read as the helical groove 4.

[0011] First, the current situation in which droplets of ink 3 are scattered toward the printed material will be explained using Figure 3. The printed material is in contact with the upper part of the outer circumferential surface of the gravure plate cylinder 1 shown in Figure 3. A close observation of the ink 3 on the outer circumferential surface of the current finisher roll 2 reveals that, as indicated by the white arrows in Figure 3, the ink 3 flows out from the axial end faces of the finisher roll 2, reducing the thickness of the ink 3 at both axial ends of the outer circumferential surface. Furthermore, as indicated by the small arrows in Figure 3, droplets of ink 3 are observed scattering toward the printed material from both axial ends of the outer circumferential surface of the finisher roll 2 where the film thickness is reduced. This is thought to be due to the reduced surface tension of the ink 3 in those areas as a result of the reduced film thickness of the ink 3. As described in Patent Document 2 above, the current furnisher roll 2 has one continuous groove (vertical groove) with a square cross section formed in the circumferential direction at each of the axial ends of its outer peripheral surface, but this groove does not appear to suppress or prevent the scattering of ink droplets.

[0012] Therefore, we considered that if the ink 3 adhering to the outer peripheral surface of the furnisher roll 2 could be made to flow toward the axial center at each of the axial ends of the outer peripheral surface, as shown by the white arrows in Figure 2, it would be possible to suppress the outflow of ink 3 from the axial end faces and ensure the film thickness of ink 3 at each of the axial ends of the outer peripheral surface, thereby preventing the scattering of ink droplets. As a result, as will be described later, by forming spiral grooves 4 within a predetermined range from each axial end face at each of the axial ends of the outer peripheral surface of the furnisher roll 2, it was possible to prevent the scattering of ink droplets. In order to make the ink 3 on the outer peripheral surface flow toward the axial center by the spiral grooves 4 at each of the ends of the furnisher roll 2 that rotate in the same direction, the lead direction of the spiral grooves 4 associated with the rotation of the furnisher roll 2, in other words, the twist direction, must be opposite at each of the axial ends. For example, as shown in FIG. 2, when the front side of the outer circumferential surface of the furnisher roll 2 rotates from bottom to top, the lead direction of the spiral groove 4 at the right end in the figure must be counterclockwise from right to left when viewed from the right end face, and the lead direction of the spiral groove 4 at the left end in the figure must be clockwise from left to right when viewed from the left end face. Therefore, as described in Patent Document 1, a spiral groove provided continuously over the entire axial length of the outer circumferential surface of the furnisher roll 2 cannot achieve this effect. Furthermore, the spiral groove 4 must not penetrate the axial end face at any axial end of the furnisher roll 2. Furthermore, it is preferable that the spiral groove 4 be formed in multiple strips at each axial end of the furnisher roll 2. Furthermore, it is preferable that the lead angle of the spiral groove 4 relative to the direction perpendicular to the axial direction on the outer circumferential surface of the furnisher roll 2 is less than 45°. Furthermore, it is preferable that the cross-sectional shape of the spiral groove 4 perpendicular to the lead angle be an arc. [Example]

[0013] Based on the above considerations, we conducted experiments to examine the effectiveness of preventing ink droplet scattering by changing various specifications of the spiral groove 4, such as its shape, width, and depth. Initially, we did not go as far as to create a spiral groove, but instead tried an oblique groove (inclined groove) 41, as shown in Figure 6. Unlike the spiral groove 4, the oblique groove 41 does not have a constant lead angle when viewed from any point in the circumferential direction of the outer circumferential surface. Instead, the groove formation direction (inclination angle) is constant only when the outer circumferential surface is viewed from the depth direction of the groove. Furthermore, in the first trial, the inclination direction of the oblique groove 41 was the direction (reverse direction) in which the ink 3 on the outer circumferential surface of the furnisher roll 2 flows out from the axial end face. The specifications of the (spiral) groove, including the oblique groove 41, were specified as shown in Figures 4 to 6. That is, the experiment was conducted by changing the groove width as groove width w (mm), groove depth as groove depth d (mm), the distance from the axial end face of the groove starting position on the axial end face of the finisher roll as groove end position a (mm), the distance from the axial end face of the groove ending position on the axial center side of the finisher roll as groove center position b (mm), groove length as groove length g, the inclination angle of the oblique groove 41 as inclination angle c (°), the lead angle of the spiral groove 4 as lead angle c (°), and also by changing the number of groove threads. Table 1 shows each parameter.

[0014] [Table 1]

[0015] As mentioned above, specimen 1 had oblique grooves 41 with an inclination direction opposite to the direction of inclination, so that the oblique grooves 41 penetrated (punched through) the axial end face of the finisher roll 2. In the table, the inclination angle c of the oblique grooves 41 of specimen 1 is shown as a negative value. Specimens 2 and 3 both had oblique grooves 41 with an inclination direction that caused the ink 3 at both axial ends of the outer circumferential surface of the finisher roll 2 to flow toward the axial center. However, specimen 2 had grooves that penetrated (punched through) the axial end face, while specimen 3 did not. In specimen 4, as shown in Figure 6, oblique grooves 41 were formed on the axial center side of the finisher roll 2, and longitudinal grooves 42 extending in the circumferential direction of the finisher roll were provided on the axial end side of the finisher roll. +25 in the table is the length of the longitudinal grooves 42. Specimens 5 to 12 all had spiral grooves 4, and except for specimen 11, the groove width w was 15 mm and the groove depth d was 5 mm. Specimens 5 and 6 had a large spiral groove 4 lead angle of 45° and nine grooves. It was recognized that unnecessary extension of the spiral groove 4 formation region toward the center of the axial direction of the furnisher roll 2 was undesirable, so specimens 5 and 6 had a small groove length g. Specimens 7 and 8 both had a smaller spiral groove 4 lead angle of 23° than specimens 5 and 6, and the number of grooves was reduced to four, but the groove length g was set slightly larger. Specimens 9 to 12 all had a spiral groove 4 lead angle of 12°, two grooves, and a large groove length g. Furthermore, specimen 11, as a comparative example, had a groove depth d of 2.5 mm. The rotation speed of the gravure printing cylinder 1 was 200 m / min, and the rotation ratio of the furnisher roll 2 was 14%, so that the rotation speed of the furnisher roll 2 was 28 m / min.

[0016] The test results showed that specimen 4 was able to reduce ink droplet scattering, but none of the oblique grooves 41 were able to prevent ink droplet scattering. In contrast, all of the spiral grooves 4 were able to prevent ink droplet scattering. However, in specimens in which the spiral grooves 4 penetrated (pierced) the axial end face of the finisher roll, ink 3 leaked out onto the axial end face of the finisher roll, resulting in an apparent lack of ink 3. In specimens 5 and 6, the large lead angle of the spiral grooves 4 caused the ink 3 in the grooves to overflow upon contact with the gravure plate cylinder 1, resulting in a disturbance of the ink 3 film surface (liquid surface) at the contact point with the gravure plate cylinder 1. Furthermore, in specimens 7 and 8, the ink 3 in the spiral grooves 4 appeared to overflow from the grooves, possibly due to the small ink capacity in the grooves. In specimen 9, the small lead angle made it difficult for the ink 3 in the grooves to flow toward the axial center of the finisher roll, so a large amount of ink 3 flowed out from the axial end face of the finisher roll where the spiral groove 4 penetrated, and it appeared that the ink 3 did not flow sufficiently toward the axial center of the finisher roll.In specimen 10, the spiral groove 4 was separated from the axial end face of the finisher roll, so the ink 3 in the outer part of the axial direction of the finisher roll flowed toward the axial end face of the finisher roll, and it appeared that the ink 3 did not flow sufficiently toward the axial center of the finisher roll.In specimen 11, the groove depth d was small and the ink capacity in the spiral groove 4 was small, so the ink 3 that overcame the spiral groove 4 flowed toward the axial end face of the finisher roll, and it appeared that the ink 3 did not flow sufficiently toward the axial center of the finisher roll. In the test piece 12, the ink 3 did not overflow from the spiral groove 4, and therefore the ink 3 film surface was not disturbed at the contact point with the gravure plate cylinder 1, and the ink 3 flowed sufficiently toward the center of the finisher roll axis.

[0017] In this embodiment, spiral grooves 4 are formed in a predetermined range from the axial end faces at both axial ends of the outer peripheral surface of the finisher roll 2, through which the ink (coating liquid) 3 flows toward the center in the axial direction as the finisher roll 2 rotates with the gravure plate cylinder 1. This prevents the ink 3 from flowing out from the axial end faces of the finisher roll 2, ensuring the film thickness of the ink 3 at both axial ends of the outer peripheral surface, and also ensuring the surface tension of the ink 3 at both axial ends of the outer peripheral surface, making it possible to prevent the ink droplets adhering to the outer peripheral surface from scattering.

[0018] In addition, by making the spiral groove 4 formed on the outer peripheral surface of the finisher roll 2 not penetrate the axial end surface of the finisher roll 2, the ink 3 in the spiral groove 4 can be prevented from flowing out toward the axial end surface of the finisher roll 2, thereby ensuring the film thickness of the ink 3 at both axial ends of the outer peripheral surface of the finisher roll 2. In addition, by forming multiple spiral grooves 4 on the outer surface of the furnisher roll 2 at each end in the axial direction, the ink 3 at both axial ends of the outer surface can be efficiently moved toward the center in the axial direction.

[0019] In addition, by making the lead angle of the spiral groove 4 formed on the outer peripheral surface of the furnisher roll 2 less than 45°, the length and capacity of the spiral groove 4 can be secured, thereby allowing more of the ink 3 at both axial ends of the outer peripheral surface to move toward the center in the axial direction. Furthermore, by making the cross-sectional shape perpendicular to the lead angle of the spiral groove 4 formed on the outer peripheral surface of the finisher roll 2 an arc cross-sectional shape, the ink 3 can flow smoothly into and out of the spiral groove 4, thereby making it possible to suppress disturbance of the liquid surface of the ink 3 at the contact point with the gravure plate cylinder 1.

[0020] The above describes the furnisher roll 2 according to the embodiment, but the present invention is not limited to the configuration described in the above embodiment and various modifications are possible within the scope of the present invention. For example, in the above embodiment, the optimum specifications of the spiral groove 4 are specified, but the specifications of the spiral groove 4 should be appropriately set depending on, for example, the rotation speed of the furnisher roll 2 and the fluidity of the ink 3. In other words, the only essential requirement for the furnisher roll 2 of the present invention is that the spiral groove 4 be formed in a predetermined range from the axial end face at both axial ends of the outer peripheral surface, allowing the ink (coating liquid) 3 to flow toward the axial center as the gravure plate cylinder 1 rotates. [Explanation of symbols]

[0021] 1 Gravure cylinder 2 furniture rolls 3 Ink (coating liquid) 4 Spiral groove

Claims

1. A furnisher roll having a cylindrical outer peripheral surface and contacting a rotating gravure plate cylinder while rotating to supply a coating liquid to the gravure plate cylinder, A furnisher roll in which spiral grooves are formed within a predetermined range from the axial end faces at both axial ends of the outer peripheral surface, through which the coating liquid flows toward the axial center as the gravure plate cylinder rotates.

2. The furnisher roll according to claim 1 , wherein the spiral groove does not penetrate through the axial end surface.

3. The furnisher roll according to claim 1 , wherein a plurality of said spiral grooves are formed at each end in the axial direction.

4. The furnisher roll according to claim 1 , wherein the spiral groove has a lead angle of less than 45° with respect to the axis-orthogonal direction on the outer circumferential surface.

5. The furnisher roll according to claim 4 , wherein the spiral groove has a cross-sectional shape orthogonal to the lead angle that is an arc cross-sectional shape.

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