JP3737947B2 - Stencil printing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary stencil printing apparatus in which a stencil sheet is wound around an outer peripheral surface of an ink-permeable cylindrical plate cylinder, and prevents ink leakage from the rear end in the rotational direction of the plate cylinder. The present invention relates to a stencil printing apparatus.
[0002]
[Prior art]
In general, a rotary stencil printing apparatus has a plate cylinder in which an ink-permeable peripheral wall is arranged in a cylindrical shape and is rotatable about its own axis. The peripheral wall has a printing region in which a large number of openings are formed and ink passes therethrough, and a non-printing region in which no openings are formed and ink does not pass around the printing region. A mesh-like screen that passes ink is wound around the outer peripheral surface of the peripheral wall. The stencil sheet thus made is wound around the outer peripheral surface of the screen. Inside the plate cylinder, there is an ink supply roller for supplying the ink to pass through the printing area on the peripheral wall and the screen on the outer peripheral surface thereof. On the outside of the plate cylinder, there is a pressing means for pressing the printing paper against the stencil sheet that is stenciled on the outer peripheral surface of the peripheral wall. Then, in synchronism with the rotation of the plate cylinder, the printing paper is supplied between the plate cylinder and the pressing means, and the printing paper is pressed against the stencil paper attached to the plate cylinder so that the perforated portion of the stencil paper is removed. Ink passes and is transferred to the printing paper and printing is performed.
[0003]
In the stencil printing apparatus as described above, there is a configuration in which ink leakage from the rear end of the printing region of the peripheral wall is prevented with respect to the rotation direction of the plate cylinder.
As shown in FIG. 4, an ink shielding member 103 is provided at the rear end 102 b of the printing region 102 of the peripheral wall 101. The ink shielding member 103 is fixed to the non-printing area 104 on the rear end 102b side of the printing area 102 and is extended to the printing area 102 side. The ink shielding member 103 opens toward the front in the rotation direction of the plate cylinder 100 and opens the printing area 102. A space 105 communicating with the inside of the plate cylinder 100 is formed.
[0004]
The ink shielding member 103 is covered with a rear end 106 b of the screen 106 wound around the outer peripheral surface of the peripheral wall 101. The front end of the screen 106 is fixed to the plate cylinder 100 on the front end side of the printing area 102 (not shown). As shown in FIG. 4, the rear end 106 b of the screen 106 is folded and a long hanger 107 is inserted, and the hanger 107 is inserted in the rotation direction of the plate cylinder 100 on the rear end 102 b side of the printing area 102. It is attached with tension applied to the rear. Thus, the screen 106 covers the printing region 102 of the peripheral wall 101 so as to contact the upper surface of the ink shielding member 103. In addition, the stencil sheet M that is stenciled on the outer peripheral surface of the screen 106 has a rear end in the rotational direction of the plate cylinder 100 positioned above the ink shielding member 103.
[0005]
In printing, the ink that has oozed out of the printing region 102 of the peripheral wall 101 by the pressing of the pressing means as the plate cylinder 100 rotates moves from the front to the rear in the rotation direction of the plate cylinder 100 on the outer peripheral surface of the peripheral wall 101. That is, the ink moves in the direction opposite to the rotation direction of the plate cylinder 100. This ink flows into the space 105 of the ink shielding member 103 at the rear end 102 b of the printing region 102 and returns to the inside of the peripheral wall 101. As a result, ink leakage at the position of the rear end 102b of the printing area 102 is prevented.
[0006]
[Problems to be solved by the invention]
However, in the above-described conventional stencil printing apparatus, the ink contained in the screen 106 may leak from the rear end of the stencil sheet M along the upper surface of the ink shielding member 103 as a large number of printings are performed. Although the ink leakage is slight, the maintenance work of the plate cylinder 100 is obstructed, and when it adheres to the printing paper, it becomes a printing stain.
[0007]
The ink leakage is considered to be caused by ink alteration or assembly variation. Ink alteration includes ink prescription change for improving image quality, evaporation of moisture in the ink when left for a long time, change in ink viscosity due to temperature change, and the like. Further, the assembly variation is mainly a variation in tension due to an error in the attachment position of the hanger 107 at the rear end 106 b of the screen 106. In addition, the assembly variation includes a change in the setting of the ink supply pressure in the plate cylinder formed by the distance between the ink supply roller and the peripheral wall, the setting of the ink supply amount by the ink supply roller, the setting of the pressing force by the pressing means, and the like.
[0008]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a stencil printing apparatus that can prevent ink leakage due to ink alteration or assembly variation in order to solve the above-described problems.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a stencil printing apparatus according to claim 1 according to the present invention is provided.
A plate cylinder having a cylindrical peripheral wall having a printing area through which ink passes and a non-printing area through which ink does not pass, and being rotatable about its own axis, and an outer peripheral surface of the peripheral wall so as to cover the printing area In a stencil printing apparatus comprising an ink-permeable screen that is wound and has a stencil sheet on its outer peripheral surface,
A hanger attached to the rear end of the screen;
Tension applying means for pulling the hanger toward the rear in the rotational direction of the plate cylinder;
An ink shielding member that is an outer peripheral surface of the peripheral wall and protrudes at a rear end position of the printing region with respect to a rotation direction of the plate cylinder;
Positioned behind the ink shielding member in the rotational direction of the plate cylinder, the ink shielding member is formed to project higher than the height projecting from the outer peripheral surface of the peripheral wall, and the hanger is placed on the peripheral wall. A spacer spaced from the outer peripheral surface;
It is provided with .
[0010]
The stencil printing apparatus according to claim 2 is the stencil printing apparatus according to claim 1,
The rear end of the screen is separated from the outer peripheral surface of the peripheral wall at the rear end position of the printing region with respect to the rotation direction of the plate cylinder, and the rear end of the screen is only partially in contact with the ink shielding member. and said that you are.
[0012]
The stencil printing apparatus according to claim 3 is the stencil printing apparatus according to claim 2 ,
The rear end of the screen is separated from the outer peripheral surface of the peripheral wall at a position higher than the height of the ink shielding member protruding from the outer peripheral surface of the peripheral wall.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a side view showing an example of a stencil printing apparatus of the present invention.
The stencil printing apparatus includes a document reading unit 1, a plate making unit 2, a printing unit 3, a paper feeding unit 4, a paper discharging unit 5, and a plate discharging unit 6.
[0014]
The document reading unit 1 is configured to be able to read a book-like bound document (hereinafter referred to as a book document) and a sheet-like document (hereinafter referred to as a sheet document).
[0015]
The configuration for reading a book document and each sheet document is mainly composed of a line image sensor 8 that is supported by a guide rail 7 and moves horizontally in the horizontal direction in the figure, and a document placement glass table on which the book document is placed. 9 and a pressure plate 10 provided on the document placing glass table 9 so as to be openable and closable.
[0016]
When reading each original, the surface to be read of the book original or sheet original is placed downward on the original placing glass table 9 and pressed from above by the pressure plate 10. Then, the line image sensor 8 is moved along the guide rail 7 by a driving device (not shown). The line image sensor 8 scans and moves between the home position position A and the scan end position B shown in FIG. As a result, the image of the document on the document placing glass table 9 is read.
[0017]
The stencil printing apparatus includes an automatic document feeder 12 for reading a plurality of sheet documents. The automatic document feeder 12 has a document set tray 13 on which a plurality of sheet documents are stacked and placed on the upper side of the stencil printing apparatus. A sheet document on the document set tray 13 is fed by the document pickup roller 14 one by one toward the target glass plate 15. A sheet document sent from the document set tray 13 is scanned and fed on the target glass plate 15 at a predetermined speed by document feed rollers 16 and 17 disposed on both sides of the target glass plate 15. At this time, the line image sensor 8 moved along the guide rail 7 is fixedly arranged at a position C (shown in FIG. 1) directly below the target glass plate 15. As a result, the image of the scanned sheet original is read. The sheet document after the reading is completed is sent out to the document discharge tray 19 by the document feed rollers 16 and 17.
[0018]
The plate making unit 2 includes a base paper roll unit 20 in which a heat-sensitive stencil sheet M made of a continuous sheet is stored in a roll shape, and a thermal head 21 composed of a plurality of point-like heating elements arranged in a horizontal row. A platen roller 22 disposed opposite to the thermal head 21, a base paper feed roller 23, a base paper guide roller 24, and a base paper cutter 25.
[0019]
The plate making unit 2 feeds the stencil sheet M drawn from the base paper roll unit 20 between the thermal head 21 and the platen roller 22 by the rotation of the platen roller 22. Further, image information relating to the image of the original read by the line image sensor 8 is input to the thermal head 21. The thermal head 21 selectively heats each point-like heating element according to the image information, and performs dot matrix-like thermal perforation printing on the stencil sheet M. The document guide roller 24 appropriately applies tension to the stencil sheet M fed between the thermal head 21 and the platen roller 22. The base paper feed roller 23 feeds the stencil base paper M that has been made to the printing unit 3. Further, the stencil sheet M which has been subjected to the plate making is cut into one plate by the base paper cutter 25.
[0020]
The printing unit 3 has a plate cylinder 26. The plate cylinder 26 has an ink-permeable peripheral wall 27 in a cylindrical shape, and is driven to rotate in the counterclockwise direction shown in FIG. 1 around its own axis. Inside the peripheral wall 27, ink supply means for supplying ink to the inner peripheral surface of the peripheral wall 27 is provided. The ink supply means mainly comprises a squeegee roller 28 and a doctor rod 29. A part of the outer peripheral surface of the plate cylinder 26 is provided with a base paper clamp unit 30 that clamps an end portion of the stencil base paper M sent from the plate making unit 2. The stencil sheet M clamped by the base paper clamp unit 30 is wound around the outer peripheral surface of the peripheral wall 27 by the rotation of the plate cylinder 26.
[0021]
The printing unit 3 includes a press roller 31 that is parallel to the axis of the plate cylinder 26. The press roller 31 is supported by a driving device (not shown) via a rotating shaft 31a. The press roller 31 is movable in a substantially vertical direction between a retracted position separated from the outer peripheral surface of the plate cylinder 26 by this driving device and a press contact position pressed against the outer peripheral surface of the plate cylinder 26. .
[0022]
The paper feed unit 4 has a paper feed base 32 on which printing paper P before printing is stacked and placed. The printing paper P placed on the paper feed tray 32 is taken out one by one by the paper feed roller 33. Further, the taken printing paper P is sent out between the plate cylinder 26 and the press roller 31 at a predetermined timing by a timing roller pair 34 synchronized with the rotation of the plate cylinder 26.
[0023]
The paper discharge unit 5 has a peeling claw 35 for peeling the printing paper P printed by the printing unit 3 from the plate cylinder 26. The printing paper P peeled off from the plate cylinder 26 is transported to a paper discharge tray 37 by a belt conveyor type paper discharge transport mechanism 36. The printed printing paper P is sequentially stacked on the paper discharge tray 37 with the print image surface as the upper surface.
[0024]
The plate removal unit 6 has a plate separation claw 38 that peels off the used stencil sheet M wound around the outer peripheral surface of the plate cylinder 26 from the plate cylinder 26. When the stencil sheet M is peeled off from the plate cylinder 26, the clamping of the stencil sheet M by the stencil sheet clamping unit 30 is released, and the end portion of the stencil sheet M released with the rotation of the plate cylinder 26 is removed from the stencil sheet separation claw 38. Try to hook it up with. The stencil sheet M caught on the plate separation claw 38 is peeled off from the outer peripheral surface of the plate cylinder 26 by the further rotation of the plate cylinder 26. The stencil sheet M peeled off by the plate separation claw 38 is conveyed by a plate discharge roller 39 and accommodated in a plate release box 40.
[0025]
In the above-described stencil printing apparatus, during printing, the base paper clamp unit 30 is opened and the plate cylinder 26 is rotated, and the stencil base paper M previously used is peeled off from the plate cylinder 26 by the plate separation claw 38, and is discharged onto the plate discharge roller 39. And accommodated in the plate removal box 40. Thereafter, a series of printing operations are performed. That is, the stencil sheet M for one plate made by the plate making unit 2 is conveyed to the plate cylinder 26 side. Then, the leading end of the stencil sheet M conveyed is clamped by the stencil sheet clamping unit 30, and is wound around the outer peripheral surface of the peripheral wall 27 by the rotation of the plate cylinder 26. Next, one sheet of printing paper P on the paper feed tray 32 is taken out and conveyed to the nip portion of the timing roller pair 34. Next, when the plate cylinder 26 rotates, the timing roller pair 34 feeds the printing paper P between the plate cylinder 26 and the press roller 31 at a predetermined timing. At the same time, the press roller 31 moves to the press contact position and presses the printing paper P against the stencil sheet M on the outer peripheral surface of the plate cylinder 26. As a result, the ink supplied to the inner peripheral surface of the peripheral wall 27 by the ink supply means passes through the perforated portion of the stencil sheet M via the ink-permeable portion of the peripheral wall 27, and a desired image is transferred to the printing paper P. Then, printing is performed. Subsequently, the printed printing paper P is peeled off from the plate cylinder 26 by the peeling claw 35, and discharged to the paper discharge tray 37 through the paper discharge transport mechanism 36.
[0026]
Details of the plate cylinder of the stencil printing apparatus will be described below.
FIG. 2 is a perspective view showing the plate cylinder, and FIG. 3 is a side sectional view showing the main part of the plate cylinder.
As described above, the plate cylinder 26 has the cylindrical peripheral wall 27. The peripheral wall 27 is wound around the outer peripheral surfaces of two opposing side plates 42 that are formed in a disc shape to form a cylindrical shape. Further, the peripheral wall 27 has a printing area 43 through which ink passes due to a porous structure as shown in FIG. 3 and a non-printing area 44 around which the ink does not pass. The printing area 43 has a rectangular shape at the center of the peripheral wall 27 when the peripheral wall 27 is unfolded, and the front end in the rotation direction of the plate cylinder 26 (the arrow direction in FIG. 2) is the front end 43a, and the rear is the rear end 43b. . The non-printing area 44 is a part other than the printing area 43.
[0027]
In the non-printing area 44 between the front end 43a and the rear end 43b of the printing area 43, the above-described base paper clamp unit 30 is provided. The base paper clamp unit 30 mainly includes a clamp base plate 45 and a clamp plate 46. The clamp base plate 45 has a long plate shape along the axis of the plate cylinder 26, and an end portion thereof is fixed to each side plate 42 by screws 47 a and 47 b together with the peripheral wall 27. The clamp plate 46 is pivotally attached to the clamp base plate 45 such that the lower surface thereof can contact and separate from the upper surface of the clamp base plate 45. A magnet plate (not shown) is fixed to the upper surface of the clamp base plate 45, and the lower surface of the clamp plate 46 is always magnetically attached to the magnet plate. Further, the clamp plate 46 is separated from the magnet plate when the lever operating point 46a is pushed by an unillustrated opening / closing mechanism. The clamp plate 46 clamps the front end of the stencil sheet M between the magnet plates when the clamp plate 46 is magnetized. Further, when the clamp plate 46 is separated from the magnet plate, the clamp plate 46 waits for the leading end of the stencil sheet M conveyed from the plate making unit 2 or opens the leading end of the stencil sheet M toward the discharging unit 6. 2, when the clamp plate 46 is separated from the magnet plate and the leading end of the stencil sheet M is opened toward the discharging unit 6, the leading end of the stencil sheet M is placed on the upper surface side of the clamp plate 46. A flip-up member 48 is provided.
[0028]
In addition, an ink shielding member 50 is provided on the peripheral wall 27. As shown in FIGS. 2 and 3, the ink shielding member 50 includes a block sheet 51 and a seal tape 52. The block sheet 51 is a longitudinal sheet material made of a resin material or the like. The block sheet 51 is an outer peripheral surface of the peripheral wall 27, and protrudes in parallel with the axis of the plate cylinder 26 at the position of the rear end 43 b of the printing region 43. As for the block sheet 51, the substantially half part covers the rear end 43b of the printing area 43, and the remaining half part is fixed to the non-printing area 44 on the rear end 43b side of the printing area 43. A half portion covering the rear end 43 b of the printing area 43 of the block sheet 51 opens a space 51 a that opens toward the front in the rotation direction of the plate cylinder 26 and communicates with the inside of the plate cylinder 26 through the printing area 43. Have. The seal tape 52 is a longitudinal sheet material made of a resin material or the like. The seal tape 52 protrudes in parallel with the axis of the plate cylinder 26 so as to straddle the rear end 43 b of the printing area 43 and the non-printing area 44 on the upper surface of the block sheet 51.
[0029]
A mesh-shaped screen 54 is wound around the peripheral wall 27. The screen 54 includes a first screen 54A and a second screen 54B having different mesh roughnesses. The first screen 54A and the second screen 54B are continuously formed in a folded shape at the front end 54a and the rear end 54b of the screen 54 in the rotational direction of the plate cylinder 26. At the front end 54a of the screen 54, a hanger 55 formed in a longitudinal shape so as to extend along the axis of the plate cylinder 26 is attached to the folded portion. The front end 54a of the screen 54 is attached to the plate cylinder 26 by fixing both ends of the hanger 55 to the side plate 42 together with the peripheral wall 27 by screws 47a. Further, a hanger 56 formed in a longitudinal shape along the axis of the plate cylinder 26 is inserted and attached to the rear end 54 b of the screen 54 with respect to the folded portion. At both ends of the hanger 56, hooks 56a are formed. The rear end 54b of the screen 54 is attached to the plate cylinder 26 by hooking each hook 56a of the hanger 56 to the head of the screw 47b and the head of the screw 47c via a tension spring 57 as a tension applying means. It is done. A tension is applied to the rear end 54 b of the screen 54 rearward in the rotational direction of the plate cylinder 26 by the tensile force of the tension spring 57. Thereby, the screen 54 covers the printing region 43 of the peripheral wall 27 without generating wrinkles.
[0030]
The hanger 56 inserted through the rear end 54 b of the screen 54 is located behind the ink shielding member 50 in the rotational direction of the plate cylinder 26. Therefore, the screen 54 also covers the ink shielding member 50. A spacer 58 is fixed to the outer peripheral surface of the peripheral wall 27 where the hanger 56 is located. The spacer 58 is formed in a longitudinal shape along the axis of the plate cylinder 26. The spacer 58 is formed such that the height from the outer peripheral surface of the peripheral wall 27 is higher than the height at which the ink shielding member 50 protrudes from the outer peripheral surface of the peripheral wall 27 (the height of the upper surface of the seal tape 52). . The hanger 56 is positioned and placed on the spacer 58.
[0031]
As shown in FIG. 3, the rear end 54 b of the screen 54 (second screen 54 </ b> B) is separated from the outer peripheral surface of the peripheral wall 27 when the hanger 56 is placed on the spacer 58. As a result, the rear end 54b of the screen 54 is separated from the rear end 43b of the printing region 43 of the peripheral wall 27 at a position higher than the height at which the ink shielding member 50 protrudes, and the block sheet 51 that is the ink shielding member 50 and the seal. Only part of the tape 52 comes into contact.
[0032]
Further, the stencil sheet M whose leading end is clamped by the base sheet clamping unit 30 is wound around the outer peripheral surface of the screen 54 (first screen 54A), and the rear end is the position of the rear end 43b of the printing region 43 as shown in FIG. To.
[0033]
In the stencil printing machine having such a configuration, during printing, the press roller 31 in the press contact position as described above causes the printing paper P to be transferred to the outer peripheral surface of the screen 54 as the plate cylinder 26 rotates in the direction of the arrow in FIG. Is pressed against the stencil sheet M wound around the sheet. Further, the press roller 31 starts to move to the retracted position at the position R1 in FIG. 3 in the vicinity of the rear end 43b of the printing area 43, and moves away from the plate cylinder 26 side at the position R2. In this printing operation, the ink that has oozed out of the printing region 43 of the peripheral wall 27 by the pressing of the press roller 31 moves in the direction opposite to the rotation direction of the plate cylinder 26 on the outer peripheral surface of the peripheral wall 27. This ink flows into the space 51 a of the ink shielding member 50 (block sheet 51) at the rear end 43 b of the printing region 43 and returns to the inside of the peripheral wall 27. Further, the seal tape 52 of the ink shielding member 50 acts as a weir when the ink runs on the upper surface of the block sheet 51.
[0034]
Further, the ink is included in the screen 54 (between the first screen 54A and the second screen 54B) as multiple printing is performed. As described above, the rear end 54 b of the screen 54 is separated from the outer peripheral surface of the peripheral wall 27 while partially contacting the upper portion of the ink shielding member 50 by the spacer 58. For this reason, the ink contained in the screen 54 is less likely to travel rearward in the rotational direction of the plate cylinder 26 from the portion away from the ink shielding member 50 at the rear end 54b. That is, the capillary action that occurs in the portion where the screen 54 is in contact is suppressed. As a result, ink leakage from the rear end of the stencil sheet M which is stenciled on the outer peripheral surface of the screen 54 is prevented.
[0035]
Further, as shown in FIG. 3, in the configuration in which the spacer 58 is formed higher than the height of the ink shielding member 50 and the hanger 56 is positioned and mounted on the spacer 58, the rear end 54 b of the screen 54 has the ink shielding. The member 50 is separated from the outer peripheral surface of the peripheral wall 27 while only partially contacting the block sheet 51 and the sealing tape 52 which are members 50. For this reason, it is possible to accurately stop the backward movement of the ink contained in the screen 54.
[0036]
Thus, by separating the rear end 54b of the screen 54 from the outer peripheral surface of the peripheral wall 27, the ink prescription is changed to improve the image quality, the moisture in the ink evaporates when left for a long time, and the ink changes due to the temperature change. It is possible to prevent ink leakage from the rear end of the stencil sheet M even if the ink is altered due to a change in the viscosity of the stencil.
[0037]
The spacer 58 not only separates the screen 54 from the outer peripheral surface of the peripheral wall 27 but also positions the hanger 56 attached to the rear end 54 of the screen 54. For this reason, the error of the attachment position of the hanger 56 is eliminated, and the tension by the tension spring 57 is maintained substantially evenly. As a result, the assembly variation in which the rear end 54 of the screen 54 is attached to the plate cylinder 26 is reduced, and ink leakage from the rear end of the stencil sheet M due to the assembly variation can be prevented. The material of the spacer 58 is not particularly limited, but the spacer 58 may be a hard resin material or metal material in order to reduce friction and maintain the posture of the hanger 56 when the hanger 56 moves in the circumferential direction of the plate cylinder 26. preferable.
[0038]
In addition, regarding the assembly variation, the setting of the ink supply pressure in the plate cylinder 26 formed by the distance between the ink supply means (squeegee roller 28) and the peripheral wall 27, and the amount of ink supplied by the ink supply means (squeegee roller 28 and doctor rod 29). Although changes such as the setting and the setting of the pressing force by the press roller 31 are conceivable, since the hanger 56 is positioned as described above, ink leakage from the rear end of the stencil sheet M can be prevented by adjusting each setting. .
[0039]
In the above-described embodiment, the ink shielding member 50 includes the block sheet 51 and the seal tape 52. Although not limited to this, although not shown, when the rear end 54 b of the screen 54 is mounted, the ink shielding member 50 may be configured by only one of the block sheet 51 and the seal tape 52. Further, the rear end 54b of the screen 54 can be attached without providing the ink shielding member 50. In this case, a position where the rear end 54 b of the screen 54 is separated from the outer peripheral surface of the peripheral wall 27 is a position beyond the rear end 43 b of the printing area 43.
[0040]
【The invention's effect】
Stencil printing apparatus of the present onset bright As described above apart at the rear end position of the print area of the peripheral wall associated with the direction of rotation of the plate cylinder, the trailing edge of the screen wound on the outer peripheral surface of the peripheral wall from the outer peripheral surface of the peripheral wall I am letting. For this reason, it becomes difficult for the ink contained in the screen to travel backward from the portion away from the peripheral wall in the rotational direction of the plate cylinder. Thereby, even if the ink is altered, it is possible to prevent ink leakage from the rear end of the stencil sheet deposited on the outer peripheral surface of the screen.
[0041]
The stencil printing apparatus of the present invention has a structure in which a hanger attached to the rear end of the screen is pulled toward the rear in the rotational direction of the plate cylinder, and the hanger is surrounded by a spacer projecting at the rear end position of the printing region. It is spaced apart from the outer peripheral surface. For this reason, since the spacer positions the hanger, there is no error in the hanger mounting position, and the tension applied by the tension applying means is maintained substantially even. As a result, the assembly variation in which the rear end of the screen is attached to the plate cylinder is reduced, so that ink leakage from the rear end of the stencil sheet due to the assembly variation can be prevented.
[0042]
The stencil printing apparatus of the present invention includes an ink shielding member that is an outer peripheral surface of the peripheral wall and protrudes at the rear end position of the printing region with respect to the rotational direction of the plate cylinder, and the rear end of the screen is positioned behind the ink shielding member. And spaced from the outer peripheral surface of the peripheral wall. During printing, the ink that oozes out from the printing region of the peripheral wall and moves in the direction opposite to the rotation direction of the plate cylinder is stopped by the ink shielding member, and further, the ink contained in the screen is stopped from moving backward. Thereby, ink leakage from the rear end of the stencil sheet deposited on the outer peripheral surface of the screen can be prevented in a double manner.
[0043]
In the stencil printing apparatus of the present invention , the rear end of the screen is separated from the outer peripheral surface of the peripheral wall at a position higher than the height protruding from the outer peripheral surface of the peripheral wall of the ink shielding member. For this reason, the rear end of the screen is separated from the outer peripheral surface of the peripheral wall while only partially contacting the ink shielding member. Accordingly, it is possible to accurately stop the ink contained in the screen from moving backward, and to accurately prevent ink leakage from the rear end of the stencil sheet that has been stenciled on the outer peripheral surface of the screen.
[Brief description of the drawings]
FIG. 1 is a side view showing an example of a stencil printing apparatus of the present invention.
FIG. 2 is a perspective view showing a plate cylinder.
FIG. 3 is a side sectional view showing a main part of the plate cylinder.
FIG. 4 is a side sectional view showing a main part of a plate cylinder in a conventional stencil printing apparatus.
[Explanation of symbols]
26 ... Plate cylinder, 27 ... Peripheral wall, 43 ... Printing area, 43b ... Rear end, 50 ... Ink shielding member, 54 ... Screen, 54b ... Rear end, 56 ... Hanger, 57 ... Tension spring (tension applying means), 58 ... Spacer.

Claims (3)

A plate cylinder having a cylindrical peripheral wall having a printing area through which ink passes and a non-printing area through which ink does not pass, and being rotatable about its own axis, and an outer peripheral surface of the peripheral wall so as to cover the printing area In a stencil printing apparatus comprising an ink-permeable screen that is wound and has a stencil sheet on its outer peripheral surface,
A hanger attached to the rear end of the screen;
Tension applying means for pulling the hanger toward the rear in the rotational direction of the plate cylinder;
An ink shielding member that is an outer peripheral surface of the peripheral wall and protrudes at a rear end position of the printing region with respect to a rotation direction of the plate cylinder;
Positioned behind the ink shielding member in the rotational direction of the plate cylinder, the ink shielding member is formed to project higher than the height projecting from the outer peripheral surface of the peripheral wall, and the hanger is placed on the peripheral wall. A spacer spaced from the outer peripheral surface;
A stencil printing apparatus comprising: The rear end of the screen is separated from the outer peripheral surface of the peripheral wall at the rear end position of the printing region with respect to the rotation direction of the plate cylinder, and the rear end of the screen is only partially in contact with the ink shielding member. The stencil printing apparatus according to claim 1, wherein: 3. The stencil printing according to claim 2 , wherein a rear end of the screen is separated from the outer peripheral surface of the peripheral wall at a position higher than a height of the ink shielding member protruding from the outer peripheral surface of the peripheral wall. apparatus.

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