Stencil printer

Abstract

To prevent overflow.SOLUTION: A stencil printer includes: ink supply means 24 that supplies ink to an ink receiver; an ink sensor 27 that detects an ink reservoir IR; and a control part 11 that calculates a leaving time of a printing drum 20 from a time point of previous use, causes the ink supply means 24 to supply a predetermined amount of ink according to the calculated leaving time, and then, when the ink reservoir IR is not detected by the ink sensor 27, causes the ink supply means 24 to execute intermittent ink supply of repeating ink supply and ink stop.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a stencil printing machine that prevents overflow. [Background technology]

[0002] When ink in a printing drum used in a stencil printer is left for a long period of time, the water content evaporates and the ink thickens. Because the thickened ink is difficult to mix with newly supplied ink, the ink dispersion effect caused by the rotation of the drive rod is hindered.

[0003] As a result, the supplied ink accumulates near the ink supply section of the distributor, causing the distribution of the ink volume in the ink pool to be uneven in the direction of the central axis. When this difference in ink vortex diameter occurs, if the vortex diameter of the ink sensor section, which detects the ink vortex diameter and controls whether or not ink is supplied, is small, it will be determined that there is an ink shortage, resulting in an oversupply of ink. In this case, there is a possibility that a phenomenon known as overflow will occur, in which some of the ink does not pass through the gap between the ink supply roll and the ink control roll and spills over the top of the ink control roll.

[0004] If overflow occurs, the uniform supply of ink to the inner peripheral surface of the printing drum by the ink layer is hindered, resulting in a decrease in print quality.

[0005] The technology described in Patent Document 1 discloses a stencil printing device equipped with an ink equalization means that can move between a retracted position where it is retracted from the ink receiving section and an advanced position where it is advanced into the ink receiving section, and that equalizes the distribution of ink volume in the ink pool in the direction of the rotation axis of the printing drum by moving from the retracted position to the advanced position. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-84300 Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, if the ink inside the print drum is left unused for a long period of time, the ink may thicken due to evaporation of water. When the machine is started after being left unused and ink is supplied, ink with normal viscosity is supplied on top of the thickened ink.

[0008] However, with the technology described in Patent Document 1, it can take a considerable amount of time for the ink to mix due to differences in viscosity. If ink supply is continued while it takes a long time for the ink to mix, an excess ink vortex may be supplied in some areas, which may lead to overflow.

[0009] SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a stencil printing machine which can prevent overflow. [Means for solving the problem]

[0010] In order to achieve the above object, the stencil printing apparatus according to the present invention is characterized by: In a stencil printing apparatus, an ink reservoir is formed by storing ink in an ink receiving section between an ink supply roller and an ink control roller inscribed on a printing drum, and the ink is supplied from the ink reservoir to the printing drum by rotating the printing drum and the ink supply roller, an ink supply unit that supplies ink to the ink receiving unit; an ink detection unit that detects the ink pool; a control unit that calculates an unused time since the printing drum was last used, causes the ink supply unit to supply a predetermined amount of ink according to the calculated unused time, and then, if the ink detection unit does not detect the ink accumulation, causes the ink supply unit to execute intermittent ink supply by repeating ink supply and ink stop; The reason is that it is equipped with the following. [Effects of the Invention]

[0011] According to the features of the stencil printing machine of the present invention, overflow can be prevented. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram of a stencil printing apparatus according to an embodiment of the present invention; [Figure 2] FIG. 1(a) shows the amount of ink that accumulates on the printing drum due to being left unused in a stencil printing device according to one embodiment of the present invention, and FIG. 1(b) shows an example of a table of unused time that associates the unused time with the amount of ink corresponding to that unused time. [Figure 3] FIG. 10 is a diagram showing an example of an intermittent ink supply table showing intermittent ink supply in a stencil printing machine according to one embodiment of the present invention. [Figure 4] 4 is a flowchart showing the processing contents in the stencil printing apparatus according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or equivalent parts and components are designated by the same or equivalent reference numerals throughout the drawings. However, it should be noted that the drawings are schematic and may differ from the actual product. Furthermore, the drawings may include parts with different dimensional relationships and ratios.

[0014] Furthermore, the embodiments shown below are merely examples of devices that embody the technical concept of the present invention, and the technical concept of the present invention does not limit the arrangement of each component to that shown below. Various modifications can be made to the technical concept of the present invention within the scope of the claims.

[0015] FIG. 1 is a schematic diagram of a stencil printing machine according to one embodiment of the present invention.

[0016] As shown in Fig. 1, the stencil printing machine 10 has a control unit 11 and a printing unit 13. Printing paper is fed from a paper feed unit 14 to the printing unit 13, and printing paper printed in the printing unit 13 is discharged to a paper discharge unit 15. Each unit of the stencil printing machine 10 is controlled collectively by the control unit 11.

[0017] The printing unit 13 has a cylindrical printing drum 20, a squeegee roller (ink supply roller) 21 provided inside the printing drum 20, and a doctor roller (ink control roller) 22 arranged adjacent to the squeegee roller 21.

[0018] The printing drum 20 is supported rotatably about a rotation axis extending in its axial direction (a direction perpendicular to the plane of the paper in FIG. 1), and is driven to rotate by the driving force of a drum drive unit (not shown). The printing drum 20 is ink permeable, and a stencil paper (not shown) made in a stencil making unit (not shown) is wound around the outer circumferential surface of the printing drum 20.

[0019] The squeegee roller 21 and the doctor roller 22 are each cylindrical members extending in the direction of the rotation axis of the printing drum 20. The squeegee roller 21 is supported so as to be rotatable about a rotation axis parallel to the rotation axis of the printing drum 20. The doctor roller 22 is fixed to the squeegee roller 21 with a specified gap therebetween.

[0020] An ink receiving section 23 extending in the direction of the rotation axis of the print drum 20 is formed between the squeegee roller 21 and the doctor roller 22. Ink is supplied to the ink receiving section 23 from ink supply means 24. The ink supply means 24 has an ink bottle 24a filled with ink, and an ink discharge section 24b that discharges ink from the ink bottle 24a into the ink receiving section 23. The ink supplied from the ink supply means 24 is stored in the ink receiving section 23 and forms an ink pool IR extending in the direction of the rotation axis of the print drum 20.

[0021] The ink stored in the ink pool IR forms an ink film on the outer peripheral surface of the squeegee roller 21, with the amount of ink supplied being adjusted by the gap between the squeegee roller 21 and the doctor roller 22. The squeegee roller 21 is positioned with a small gap from the inner peripheral surface of the printing drum 20, and is inscribed on the inner peripheral surface of the printing drum 20 via the ink film on the outer peripheral surface of the squeegee roller 21. During printing, the printing drum 20 rotates in the direction F1 in Figure 2, and the squeegee roller 21 rotates in the direction F2 accordingly. When the squeegee roller 21 rotates in the direction F2, ink is drawn out of the ink pool IR and supplied to the portion of the squeegee roller 21 that is inscribed on the printing drum 20.

[0022] An ink drive rod 25 is provided in the ink receiver 23. The ink drive rod 25 extends in the direction of the rotation axis of the print drum 20 and is driven to rotate by a drive means. The rotation of the squeegee roller 21 and the ink drive rod 25 causes the ink in the ink reservoir IR to flow, and the ink is spread in the direction of the rotation axis of the print drum 20.

[0023] A press roller 29 is provided on the outside of the printing drum 20. In synchronization with the rotation of the printing drum 20, printing paper P transported from the paper feed section 14 is supplied between the printing drum 20 and the press roller 29. The press roller 29 presses the printing paper P against the stencil paper on the outer peripheral surface of the printing drum 20. This pressure causes ink from the printing drum 20 to pass through the holes in the stencil paper and transfer to the printing paper P, thereby performing stencil printing. The printing drum 20 rotates a predetermined amount in the direction F1, and when printing on one sheet of printing paper P is completed, the printed printing paper P is peeled off from the printing drum 20 and discharged to the paper discharge section 15.

[0024] When printing is performed by the printing unit 13, ink in the ink reservoir IR is supplied to the print drum 20 via the squeegee roller 21 and consumed. An ink sensor 27 that detects the amount of ink in the ink reservoir IR is provided near the ink receiver 23. When the ink sensor 27 detects a decrease in the ink in the ink reservoir IR, the control unit 11 causes ink to be supplied from the ink supply means 24 to replenish the consumed ink.

[0025] The control unit 11 also calculates the time that the print drum 20 has been left unused since it was last used, and controls the ink supply unit 24 to supply a predetermined amount of ink according to the calculated time that the print drum 20 has been left unused.

[0026] Fig. 2(a) shows the amount of ink in the ink pool IR caused by leaving the printing drum 20 unused in the stencil printing machine 10 according to one embodiment of the present invention, and Fig. 2(b) shows an example of an unused time table that associates the unused time with the ink amount corresponding to the unused time. This unused time table is stored in the internal memory of the control unit 11.

[0027] 2(a), when the ink pool IR in the printing drum 20 of the stencil printing machine 10 is left for a long period of time, the amount of ink decreases due to evaporation of water, and as a result, the viscosity increases. In other words, the longer the time is left, the less ink there is in the ink pool IR.

[0028] Therefore, the control unit 11 calculates the time that the print drum 20 has been left unused since it was last used, and causes the ink supply means 24 to supply a predetermined amount of ink according to the calculated time that the print drum 20 has been left unused.At this time, the control unit 11 calculates the amount of ink to be supplied from the ink supply means 24 based on the table of time that the print drum 20 has been left unused, as shown in Figure 2(b).

[0029] 2(b), the unused time table associates the unused time since the print drum 20 was last used with the amount of ink supplied from the ink supply means 24 according to the unused time. The amount of ink is set to increase as the unused time increases.

[0030] The control unit 11 extracts the ink amount corresponding to the calculated unused time from the time when the print drum 20 was last used from the unused time table, and causes the ink supply means 24 to supply ink in the extracted ink amount.

[0031] After the control unit 11 has caused the ink supply means 24 to supply ink, if the ink sensor 27 does not detect an ink pool IR, the control unit 11 causes the ink supply means 24 to perform intermittent ink supply, which repeats ink supply and ink stop.

[0032] FIG. 3 is a diagram showing an example of an intermittent ink supply table showing intermittent ink supply in the stencil printing machine 10 according to one embodiment of the present invention.

[0033] 3, the intermittent ink supply table associates an intermittent pattern, which is a combination of supply time and stop time, with each type of ink (inks A to C) and each standing time. The intermittent ink supply table is stored in the internal memory of the control unit 11.

[0034] For example, if the time since the print drum 20 was last used with ink B is three days, the intermittent pattern is a combination of a supply time of 1 (s) and a stop time of 16 (s).

[0035] If the ink sensor 27 does not detect an ink pool IR after ink is supplied from the ink supply means 24, the control unit 11 extracts an intermittent pattern corresponding to the type of ink being used and the time of leaving it on the basis of the intermittent ink supply table, and causes the ink supply means 24 to perform intermittent ink supply that repeats ink supply and ink stoppage based on the extracted intermittent pattern.

[0036] FIG. 4 is a flowchart showing the processing contents in the stencil printing machine 10 according to one embodiment of the present invention.

[0037] As shown in FIG. 4, when the printing drum 20 starts to rotate, such as when plate making or printing starts, in step S101, the control unit 11 extracts from the idle time table the amount of ink corresponding to the calculated idle time since the printing drum 20 was last used, and causes the ink supply means 24 to supply ink in the extracted amount of ink.

[0038] In step S103, the control unit 11 determines whether the ink sensor 27 has detected an ink pool IR.

[0039] If the ink sensor 27 does not detect the ink pool IR (step S103; NO), it can be inferred that the viscosity of the ink pool IR is high and that the supplied ink is accumulating near the ink supply means 24, so in step S105 the control unit 11 executes an ink vortex stabilization operation. Specifically, the control unit 11 extracts an intermittent pattern corresponding to the type of ink being used and the standing time based on the intermittent ink supply table, and causes the ink supply means 24 to execute intermittent ink supply, which repeats ink supply and ink stoppage, based on the extracted intermittent pattern.

[0040] On the other hand, if the ink sensor 27 detects the ink pool IR (step S103; YES), it can be assumed that the ink supplied by the ink supply means 24 has mixed in the ink pool IR, causing the viscosity of the ink pool IR to decrease, and therefore in step S107, the control unit 11 executes normal operations such as plate making and printing.

[0041] (Addendum) The present application discloses the following inventions.

[0042] (Appendix 1) In a stencil printing apparatus, an ink reservoir is formed by storing ink in an ink receiving section between an ink supply roller and an ink control roller inscribed on a printing drum, and the printing drum and the ink supply roller are rotated to supply the ink from the ink reservoir to the printing drum, an ink supply unit that supplies ink to the ink receiving unit; an ink detection unit that detects the ink pool; a control unit that calculates an unused time since the printing drum was last used, causes the ink supply unit to supply a predetermined amount of ink according to the calculated unused time, and then, if the ink detection unit does not detect the ink accumulation, causes the ink supply unit to execute intermittent ink supply by repeating ink supply and ink stop; A stencil printing apparatus comprising:

[0043] This allows the ink in the ink pool to mix, making the vortex diameter of the ink pool uniform, allowing the ink detection unit to properly detect the ink and preventing excessive ink supply, thereby preventing overflow. [Explanation of symbols]

[0044] 10 Stencil printing device 11 Control section 13 Printing Department 14 Paper feed section 15 Paper output section 20 printing drums 21 Squeegee roller (ink supply roller) 22 Doctor roller (ink control roller) 23 Ink receiver 24 Ink supply means 24a ink bottle 24b Ink ejection section 25 Ink Drive Rod 27 Ink sensor 29 Press roller

Claims

[Claim 1] In a stencil printing apparatus, an ink reservoir is formed by storing ink in an ink receiving section between an ink supply roller and an ink control roller inscribed on a printing drum, and the printing drum and the ink supply roller are rotated to supply the ink from the ink reservoir to the printing drum, an ink supply unit that supplies ink to the ink receiving unit; an ink detection unit that detects the ink pool; a control unit that calculates an unused time since the printing drum was last used, causes the ink supply unit to supply a predetermined amount of ink according to the calculated unused time, and then, if the ink detection unit does not detect the ink accumulation, causes the ink supply unit to execute intermittent ink supply by repeating ink supply and ink stop; A stencil printing apparatus comprising:

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