JP3418232B2 - Printing drum of rotary stencil printing machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary stencil printing machine, and more particularly to the structure of its printing drum.

[0002]

2. Description of the Related Art The same applicant as the applicant of the present invention can quickly start up a rotary stencil printing machine at the time of start-up and obtain a stencil printed matter of good finish from the first to second sheets with almost no need for trial printing. It is possible to operate by pushing each printing paper between the printing drum and the back-pressing roller, and separating the printing drum and the back-pressing roller from each other at the printing break between the printing papers. In the rotary type stencil printing machine, it is necessary to frequently reciprocate a member having a considerable mass such as a printing drum or a back-pressing roller, which restricts an increase in printing speed. ,
Instead of the traditional rigid cylindrical printing drum, the main part between both ends of the printing drum on which the stencil sheet is wound is composed of a flexible perforated sheet, and along the inner surface of the cylindrical body. A part of the cylindrical body is bulged outward in the radial direction by the rolling centering roller, and the printing drum is rotated when printing on the printing paper, while the centering roller opposes the backing roller. Inflate a part of the body one by one,
Japanese Patent Application No. 63-28553 (Japanese Patent Application Laid-Open No. 1-2047) discloses a rotary stencil printing device which is capable of performing stencil printing on a printing paper sandwiched between a backing roller and a bulging portion of a flexible cylinder.
No. 81), and a further improvement thereof is a flexible porous sheet in which the above-mentioned flexible cylinder has a rectangular expanded shape, and both ends of the flexible drum form the both ends of the printing drum. Japanese Patent Application No. 1-4702 of a rotary stencil printing machine having a structure in which each of the two annular portions is freely seated on the outer peripheral surface thereof.
No. 9 (Japanese Patent Laid-Open No. 2-225078).

When the flexible perforated sheet is a sheet such as a net material formed by woven, non-woven or knitted wire rods, two annular portions forming both ends of the printing drum at both side edge portions. When the intermediate portion of the flexible porous sheet wound in a cylindrical shape while being seated on the outer peripheral surface of the section is pushed outward in the radial direction by the intermediate pushing roller, the flexible porous sheet is pushed by the intermediate pushing roller. Further, it is possible to obtain a stencil printed matter that bulges outward in the radial direction almost uniformly over the entire width and has a uniform finish over the entire width direction. In this case, in particular, as in the above-mentioned improved type, a flexible porous sheet having a rectangular expanded shape is wound into a cylindrical body with both side edges freely seated on the outer peripheral surface of the annular portion. During this time, the cylinder exhibits greater flexibility and uniformity against radial outward swelling by the centering roller.

[0004]

However, the cylindrical body is more uniformly extruded over the entire area in the widthwise direction against the outward pressing in the radial direction by the intermediate pressing roller, and the printing speed is further increased. In order to achieve this, it is desired that the cylindrical body has a structure that is more lightly and uniformly bulged with respect to the outward pushing in the radial direction by the intermediate pressing roller.

In view of the above-mentioned circumstances, the present invention expands even more lightly and uniformly when the flexible porous sheet constituting the cylindrical body of the printing drum is pushed outward from the inside by the intermediate pushing roller. It is an object of the invention to provide a printing drum of a rotary stencil printing machine which is improved so as to be issued.

[0006]

According to the present invention, there is provided a printing drum including a cylindrical body having a porous structure for carrying a perforated stencil sheet in a wound state. The ink supplied from the inside is pressed by an intermediate pressing roller that rolls along the inner surface of the cylindrical body and is supplied to the stencil sheet through the holes of the cylindrical body, and a part of the cylindrical body is predetermined by the intermediate pressing roller. Of a rotary stencil printing machine for performing stencil printing on the printing paper pressed against the cylindrical body by the back-pressing means when the printing drum is rotated while being bulged outward in the radial direction by a substantial bulge amount of A printing drum, which comprises two annular portions forming both ends of the printing drum and a crossbar portion having a stencil sheet starting edge attaching device that connects the two annular sections and selectively attaches the starting edge of the stencil sheet. A frame containing A printing drum including a flexible perforated sheet having a substantially rectangular expanded shape that can be freely seated on the outer peripheral surface of each of the two annular portions at a side edge portion, and a flexible porous sheet that constitutes the cylindrical body. , The flexible porous sheet has its starting end fixed to the frame near the cross bar, and its end moves near the cross bar along the outer peripheral surface of the annular part. This is achieved by a printing drum characterized in that it is guided by guide means which guide it substantially freely movably along the path.

Incidentally, in the description of the present specification, the flexible porous sheet may be porous in the central main portion through which the ink is allowed to pass in view of its function, and the peripheral portion of the peripheral portion thereof. It does not mean that the edges are all porous,
In addition, it also includes those in which the start end and the end are reinforced by a suitable non-porous sheet material for the convenience of installation.

In the printing drum having the above structure, the guide means is provided in the frame body so as to extend in the direction along the outer peripheral surface of the annular portion, and is a slit for receiving the end portion of the flexible porous sheet. May be included.

In the printing drum having the above structure, the guide means extends across the slit and engages with a long hole formed in the longitudinal direction of the flexible perforated sheet at the end portion thereof. It may include a guide pin to operate.

Alternatively, instead of the guide means for the end portion of the flexible porous sheet by the slit, the guide means projects outward in the radial direction from the frame body and surrounds the end portion of the flexible porous sheet. A guide pin that engages with a long hole provided so as to extend in the direction, and the guide pin is passed through the long hole at the end of the flexible porous sheet and then locked to the tip of the guide pin. And a retaining element for preventing the end portion of the flexible porous sheet from coming off from the guide pin. In this case, the terminal end portion of the flexible porous sheet may include a plate member connected to the main body portion of the flexible porous sheet by hooking means, and the elongated hole may be formed in the plate member.

In the printing drum having the above-mentioned structure, the flexible porous sheet forms a cylindrical body by its own elasticity in a state where both side edges thereof are not restrained by the two annular portions. It may be pre-elastically curved to be rounded.

In the printing drum having the above-mentioned structure, the stencil sheet starting end attaching device holds the starting end of the stencil sheet at the attaching position on the cross bar and the first rotating position. A flap that is selectively pivoted between a second pivot position inverted from the position, the flap engaging the end of the flexible perforated sheet when in the second pivot position. It is possible to prevent the terminal portion from moving in the circumferential direction.

In the printing drum having the above structure, the flexible porous sheet end portion movement preventing device for selectively preventing the movement of the end portion of the flexible porous sheet in the circumferential direction is provided.
The flexible perforated sheet end movement prevention device is linked with the stencil sheet starting end attaching device being brought to an operating position for holding the starting end of the stencil sheet at the attaching position on the cross bar portion. It may be adapted to release the part movement preventing action.

The printing drum according to the present invention does not necessarily require a roller as a means for supporting the printing paper from the back side in order to press the printing paper against it, but a flat plate having a highly slippery surface or an arc shape. It may be used together with other printing paper backing means such as a curved plate.

The flexible porous sheet is a woven or knitted sheet of fiber or wire, a non-woven sheet of fiber or wire, a sheet of plastic or metal with a large number of small holes perforated, or a composite. Which has been prepared so as to have appropriate ink permeability and flexibility.

[0016]

As described above, the printing drum is provided with the two annular portions constituting both ends thereof and the stencil sheet starting edge attaching device for connecting the two annular portions and selectively attaching the starting edge of the stencil sheet. A flexible porous sheet that forms a cylindrical body having a substantially rectangular expanded shape that can be freely seated on the outer peripheral surface of each of the two annular portions at both side edge portions, and a frame body that includes a cross member. The stencil sheet is wound around a cylindrical body formed by a flexible porous sheet, and the ink supplied from the inside of the cylindrical body is pressed by an intermediate pressing roller that rolls along the inner surface of the cylindrical body. And is supplied to the stencil sheet through the holes of the cylinder, and is back-pressed when the printing drum rotates while the part of the cylinder is bulged outward in the radial direction by a predetermined substantial bulge by the intermediate pressing roller. Pushing against the cylinder by means When the stencil printing is performed on the scraped printing paper, the flexible perforated sheet starts from the starting end and is pressed against the back-pressing means through the stencil paper and the printing paper by the intermediate pressing roller. In this state, since the flexible porous sheet is squeezed in the circumferential direction toward its end portion, if the start end portion of the flexible porous sheet is fixed to the frame body in the vicinity of the cross bar portion, the end portion thereof is particularly the above-mentioned Japanese Patent Application. Flat 1-4702
Even if it is not held in a state where it is elastically stretched in the circumferential direction by a spring as proposed in No. 9, simply moving substantially freely along a moving path along the outer peripheral surface of the annular portion. If the guide is possible, it functions sufficiently as a cylindrical portion of the printing drum, and rather, the end portion thereof can be moved substantially freely along the movement path along the outer peripheral surface of the annular portion, so that the intermediate pressing can be performed. The flexible perforated sheet is extruded more lightly by the roller, the print finish becomes more uniform over the entire printing paper, and a finer printed image is more faithfully formed.

Further, a stencil sheet starting end attaching device which is provided on the cross bar portion and attaches the starting end of the stencil sheet onto the cross bar portion is constituted as a flap which is reversed from a position where the starting end of the stencil sheet is held on the cross bar portion. When the flap is in the reverse position, it engages with the end portion of the flexible perforated sheet to prevent the end portion from moving in the circumferential direction, or the stencil sheet starting end attachment device attaches the starting end of the stencil sheet. The flexible perforated sheet end movement blocking device, which is deactivated in conjunction with being brought to the operating position for holding it in the mounting position on the cross member, selectively blocks the circumferential movement of the flexible perforated sheet. As a result, during printing, the flexible porous sheet is smoothly swollen by the intermediate pressing roller due to the circumferential movement of the end portion of the flexible porous sheet, and the stencil sheet is peeled off from the printing drum. Sometimes the flexible perforated sheet is a phenomenon dragged by stencil sheet lifted from the annular portion being plate discharge is prevented due to the viscosity of the ink, the cylindrical body of the flexible perforated sheet even during plate discharge is kept in a stable state.

[0018]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 attached herewith schematically illustrates the basic construction of a rotary stencil printing machine in which a cylindrical body which constitutes a main part of a printing drum is constituted by a flexible porous sheet which is the object of the present invention. The basic structure of the rotary stencil printing machine shown in this figure is the same as the above-mentioned Japanese Patent Application No. 63-28553 and Japanese Patent Application No.
-47029. That is, in FIG. 1, 1 is a printing drum, 2 is a back-pressing roller, and 3 is an intermediate-pressing roller. The cylindrical portion of the printing drum 1 excluding both ends is made of a flexible porous sheet, and the middle pressing roller 3 rotatably supported by an arm member 5 pivoting around a pivot axis 4 is located on the left side. When the print drum 1 is retracted inside the natural cylindrical shape of the print drum 1 as shown in FIG. A, the outer peripheral surface of the print drum 1 is separated from the backing roller 2 by a gap 6, but shown in the right side of FIG. Thus, when the arm member 5 is rotated around the pivot axis 4 in the counterclockwise direction in the figure, the intermediate pressing roller 3 pushes the cylindrical portion of the flexible porous sheet of the printing drum outward in the radial direction, The printing paper 8 inserted into the gap 6 by the feeding roller 7 is pushed between the bulging portion and the back-pressing roller 2, and the printing drum 1
Stencil printing is performed on the printing paper 8 with a perforated image of the perforated stencil sheet that is wound around the.

FIG. 2 is a perspective view showing the print drum 1 taken out. The structure of the printing drum shown in FIG. 2 shows the basic configuration proposed in the above-mentioned Japanese Patent Application No. 1-47029, that is, the printing drum has two annular portions 10a constituting both ends thereof. 10b and a frame member including a cross-bar portion 12 connecting these two annular parts, on which a stencil sheet starting-edge mounting device 14 for selectively attaching the start end of the stencil sheet is provided. There is. In the structure shown, the stencil sheet starting end attachment device 14 has a flap 18 which is rotated by a shaft 16 about an axis of the shaft about 180 degrees, so that the starting end of the stencil sheet is crossed. The leading end of the stencil sheet is selectively attached to the crossbar portion 12 by selectively sandwiching it between the portion 12 and the flap 18.

A flexible porous sheet 20 having a rectangular expanded shape has annular portions 10 on both side edges 20a and 20b.
It is wound into a cylindrical shape while being freely seated on the outer peripheral surfaces of a and 10b, and constitutes a cylindrical body of the printing drum. Although not shown in this figure, the above-mentioned Japanese Patent Application No. 1-4
In the printing drum proposed in No. 7029, the flexible porous sheet 20 is fixed to the cross bar portion 12 at the starting end portion as viewed along the rotation direction of the printing drum, and the ending end portion. It is attached with a tension load applied by a spring. In the structure of the printing drum shown in FIG. 2, the flexible porous sheet 20 is a net material formed by weaving a wire material.

Gears 22a and 22b are formed integrally with the annular portions 10a and 10b, and these gears are meshed with corresponding gears provided at both ends of the backing roller 2, or It engages with a pinion (not shown) incorporated in the printing apparatus, and serves to drive the printing drum to rotate.

FIG. 3 is a similar perspective view showing a print drum having substantially the same construction as the print drum shown in FIG. 2, but in which the flexible porous sheet 20 is shown. It is made of a thin metal plate having elasticity, and has a porous structure by perforating a large number of pores in the central portion except both side edges of the annular portions 10a, 10b which are seated on the outer peripheral surfaces of the annular portions 10a, 10b. . In FIG. 3, parts corresponding to the parts in FIG. 2 are designated by the same reference numerals as in FIG.

One embodiment in which the present invention is incorporated in a printing drum having such a basic structure is shown in FIG. 4 for the sake of clear explanation only in its essential part.

According to the present invention, the flexible porous sheet 20 is attached to the frame body composed of the cross wood portion 12 and the annular portions 10a and 10b at the starting end portion 24 thereof close to the cross wood portion 12, and the flexible porous sheet 20 is provided. The seat 20 has annular portions 10a and 10a on both side edges thereof.
While sitting on the outer peripheral surface of b, the annular portions 10a, 10b
Wrapped around the end of the flexible perforated sheet 26
Is fitted in a slit 28 provided on the lower side of the cross section 12 (the state shown in FIG. 4A on the left side in FIG. 4).
The structure around the slit 28 is shown in more detail in FIG. 5, which is a cross-sectional view taken along line VV in FIG. The slit 28 may be provided only in the annular portions 10a and 10b.

The flexible porous sheet 20 is a sheet having sufficient elasticity so that both side edges of the flexible porous sheet 20 are seated on the outer peripheral surfaces of the annular portions 10a and 10b and form a stretched cylindrical body without wrinkling. . The sheet may be a substantially flat sheet in a free state, but may be elastically curved in advance in the direction of forming the cylindrical body so that the cylindrical body can be easily rolled. In this case, the flexible perforated sheet may be elastically curved as a whole, but the zones along the both side edges 20a, 20b are particularly elastic portions, and the zones along the both side edges are made. Due to the elasticity of, the entire flexible porous sheet may have an elastic curved shape that is rounded as described above.

FIG. 4B on the right side of FIG. 4 shows that the intermediate pressing roller 3 is biased outward in the radial direction so that the flexible porous sheet 2 is formed.
The cylindrical body formed by 0 is deformed so that a part thereof bulges outward in the radial direction. In this case, when the flexible porous sheet 20 swells at the portion pressed by the intermediate pressing roller 3, the flexible porous sheet has both side edge portions of the annular portion 10a,
Since it easily slides along the outer peripheral surface of 10b, there is almost no resistance, and the swelling is extremely light. As the printing drum rotates, the bulging portion moves toward the terminal end portion 26 from the starting end portion 24 of the flexible porous sheet while being squeezed by the contact with the backing roller. Further, when the flexible porous sheet is elastically curved in advance as described above, when the flexible porous sheet 20 and a part of the flexible porous sheet are bulged, the flexible porous sheet 20 and the annular portion 10a, 10b contact the outer peripheral surface. The frictional resistance is smaller and the bulging deformation is lighter and easier to obtain. Further, in this case, the change of the elastic reaction force caused by the bulging deformation of the flexible porous sheet when the relative position of the intermediate pressing roller with respect to the flexible porous sheet moves in the circumferential direction as the printing drum rotates, is further reduced. The swelling deformation becomes small and follows lightly and quickly by the transition of the relative position of the intermediate pressing roller with respect to the flexible porous sheet.

The action of guiding the end portion 26 of the flexible porous sheet so as to be movable in the circumferential direction while the movement of the printing drum in the axial direction is restrained is that the side edge portions 2 of the flexible porous sheet are located.
0a, 20b ends (in FIG. 5, the end of the side edge portion 20a is 2
1a) is the side wall of the slit 28 (see FIG. 5).
, One of which is shown at 29a) may be provided by sliding engagement, but such circumferential guidance may be provided as in another embodiment shown in FIG. When the elongated holes extending along the longitudinal direction of the flexible porous sheet are formed on both side edges of the terminal end portion 26 of the flexible porous sheet 20, and when the guide pin 30 penetrating the elongated holes is used, it is flexible. The swelling amount of the flexible porous sheet when the flexible porous sheet is swollen by the intermediate pressing roller by guiding the porous sheet in the longitudinal direction at its terminal end and restricting the movement in the width direction at both side edges. Is uniform over the entire width of the flexible porous sheet. 6 is the same as the embodiment of FIG. 4 with respect to other configurations. In FIG.
Portions corresponding to the respective portions shown in FIG. 4 are denoted by the same reference numerals as those in FIG.

In the flexible porous sheet end portion guiding means, when the elongated hole is a closed elongated hole, the end portion of the flexible porous sheet is guided in the longitudinal direction and moved in the width direction as described above. Due to the regulation, the bulging deformation and the returning deformation of the flexible porous sheet by the middle pushing roller are more stably performed, and the bulging amount of the flexible porous sheet by the middle pushing roller is automatically limited. . However, the slot may be a slot opened at the end edge of the flexible porous sheet. In this case, the function of limiting the bulging amount is lost as described above, but the flexible porous sheet is There is an advantage that the end portion of can be inserted into and removed from the slit 28 without removing the guide pin.

FIG. 7 is a partial perspective view showing another embodiment of the printing drum according to the present invention, focusing on the mounting portion of the end portion of the flexible porous sheet, and FIG. 8 is shown in FIG. FIG. 8 is a somewhat exploded end view showing the structure of a part of the structure as viewed in the direction of arrow A in FIG. In these figures, the parts corresponding to the parts shown in FIGS. 1 to 6 are indicated by the corresponding reference numerals. In this embodiment, the end portion 26 of the flexible porous sheet 20 is constituted by a plate member 34 connected to a main body portion 20c which is a main part of the flexible porous sheet 20 by hooking means 32. . Hooking means 32
Has a structure in which a folded-back hook portion 38 formed on a part of a plate-shaped reinforcing member 36 fixed to the main body portion 20c of the flexible porous sheet is hooked in a hole 40 formed in the plate member 34. There is. The plate member 34 has elongated holes 42a and 42b extending along the circumferential direction of the printing drum at both ends thereof (however, only the elongated hole 42b is visible in FIG.
a is provided for the other end of the printing drum. The same applies hereinafter), guide pins 44a and 44b protruding radially outward from the annular portions 10a and 10b are passed through these elongated holes. Snap disks 46a and 46b that snap-engage with annular grooves cut therein are attached to the tip ends of the guide pins 44a and 44b.
After the screws 44b are passed through the slots 42a and 42b, respectively, these snap disks 46a and 46b are inserted into the guide pins 44.
Since the flexible porous sheet 20 including the plate member 34 is attached to the distal end portions of the a and 44b, the terminal end portion 26 of the flexible porous sheet 20 along the movement path along the outer peripheral surfaces of the annular portions 10a and 10b near the crossbar portion 12. It is guided to be practically freely movable. The plate member 34 has claw portions 48 near both ends thereof.
a and 48b are cut and raised, and these claws and claws 50a and 50b corresponding to the claws are provided on the cross-section 12.
Tension coil springs 52a and 52b are mounted between
For the time being, a spring force is applied to the plate member 34 toward the cross section 12, but in these tension coil springs, the flexible porous sheet 20 has cylindrical portions 1 at both side edges 20a and 20b.
0A, 10b exerts a tensile force on the end portions of the flexible porous sheet to the extent that they are in close contact with each other, and the direction in which the end portion 26 of the flexible porous sheet resists the spring force of these tension springs. In addition, a substantial spring reaction force is not exerted on the movement along the outer peripheral surfaces of the annular portions 10a and 10b.

In the illustrated embodiment, as shown in FIG. 8, the main body portion 20c of the flexible porous sheet has a terminal end extending further rearward than the portion where the reinforcing member 36 is mounted. It has an extension 20d, the end extension of which is a guide pin 44.
a and 44b are pedestals 54a and 54b, and are annular portions 10a and 1b.
Since it is fixed to 0b and the cross bar 12 is formed with legs 12a and 12b at both ends thereof,
An intermediate portion between both ends of the plate member 34 and the cross section 12 is biased outward in the radial direction, and extends to the inside of the starting end portion of the flexible porous sheet through a tunnel-like void formed therein. . The end extending portion 20d of the flexible porous sheet is a non-porous sheet portion, and is effective in preventing ink from leaking from the inside of the printing drum 1 over the cross bar portion 12 to the outside of the printing drum. Is acting on.

As described above, the main body portion 20 of the flexible porous sheet
Since the c and the plate member 34 are hooked together by the hooking means 32, the plate member 34 is held in its mounting position by removing the hooking means 32. Can be easily unwound from the state in which it is wrapped around the annular portions 10a, 10b.
Further, since the starting end portion 24 of the flexible perforated sheet is attached to the cross-bar portion 12 via the plate-like attachment reinforcing piece 56 by an easily releasable connecting means such as a screw 58, these fastening means are released. By doing so, the flexible perforated sheet can be attached to the annular portions 10a, 10b for maintenance, inspection or replacement.
It is easily removed from the frame of the printing drum composed of the cross bar 12 and the cross bar 12, and is reattached to the frame.

When the flap 18 is in the position shown in FIGS. 7 and 8, the flap 18 holds the leading edge of the stencil sheet, which is not shown in the drawing, between it and the cross bar portion 12, and releases the leading edge of the stencil sheet. Occasionally, the shaft 16 makes it about 18 from the position shown.
It is inverted by 0 ° and overlaps on the magnet piece 59 provided on the plate member 34, and is held in a state of being attracted thereto by the magnetism of the magnet piece. When the flap 18 is attracted onto the magnet piece 59 in this way, the flap 18 prevents the plate member 34 from moving in the circumferential direction via the magnet piece 59 by frictional contact with the magnet piece 59, and printing is performed during plate ejection. When the stencil sheet is peeled off from the drum, even if the end portion of the flexible porous sheet is about to be separated from the cross-bar portion by an attempt to expand the diameter of the cylindrical body of the flexible porous sheet by the dragging action due to the viscosity of the ink, The effect of pressing and blocking this is obtained.

In the embodiment shown in FIGS. 7 and 8, the magnet piece 59 is fixed on the plate member 34, but the magnet piece 59 is fixed on the flap 18 as shown in FIG. May be.

Furthermore, as in the embodiment shown in FIG. 8 or FIG. 9, the transmission of the force in the circumferential direction between the flap 18 and the plate member 34 is simply performed by the flap 18 or the plate member 34 and the magnet piece 5.
If the force based on the frictional contact due to the magnetic force between the plate members 9 is not sufficient to reliably prevent the plate member 34 from moving in the circumferential direction, as in the embodiment shown in FIG.
May be provided with a locking portion 60 that engages the end of the magnet piece 59 when it is attracted onto the magnet piece 59, such that the locking portion mechanically engages the end of the magnet piece. A reliable latching engagement that restricts the movement in the circumferential direction is achieved between the two. It will be appreciated that such mechanical engagement can be accomplished in various other ways than the illustrated embodiment.

FIG. 11 shows still another embodiment of the construction in which the peripheral movement of the end portion of the flexible porous sheet is selectively prevented in association with the operation of the stencil sheet starting end attaching device 14. It is a figure similar to 10. In this embodiment, in addition to the flap 18, a locking member 63 extending from a root portion supported by the shaft 16 to a hook-shaped tip portion 62 that selectively engages with the step portion 61 of the plate member 34 is provided. Has been. The locking member 63 is a leaf-spring-like member having elasticity and is fixed to the shaft 16 at its root portion, and when the shaft 16 is in a rotation position which brings the flap 18 to the stencil sheet starting edge holding position as shown in the drawing. The tip portion 62 is floated above the step portion 61 of the plate member 34 and is disengaged by the engagement with the step portion.
In this state, the locking member 63 does not prevent the end of the flexible porous sheet from moving in the circumferential direction.

When the shaft 16 rotates counterclockwise in the figure to release the holding of the stencil sheet starting end by the flap 18 from the state shown in the drawing, the locking member 63 moves the tip 62 of the locking member 63 downward in the drawing. The tip portion 62 is rotated so that the plate member 3
4 to prevent the flexible porous sheet end portion from moving in the circumferential direction in a direction away from the crosspiece portion 12. still,
In this case, the flap 18 does not rotate to the reverse position as in the embodiment of FIGS. 7 to 10 when it is in the non-operating state in which the starting edge of the stencil sheet is not held.

Although the present invention has been described above in detail with reference to some preferred embodiments, the present invention is not limited to these embodiments, and various other implementations are possible within the scope of the present invention. It will be apparent to those skilled in the art that examples are possible.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the basic configuration of a rotary stencil printing machine using a printing drum made of a flexible cylinder.

FIG. 2 is a perspective view showing an example of a printing drum in the case where a flexible porous sheet forming a flexible cylinder is a net material formed by weaving a wire material.

FIG. 3 is a perspective view showing an example of a printing drum in the case where a flexible porous sheet forming a flexible cylinder is made of a sheet material in which holes are perforated in a metal plate.

FIG. 4 is a schematic diagram showing one embodiment of a printing drum according to the present invention in two operating states in connection with a middle press roller.

5 is a cross-sectional view taken along line VV of FIG. 4 showing a structure around a slit.

FIG. 6 is a schematic view showing another embodiment of the printing drum according to the present invention in two operating states in connection with a middle press roller.

FIG. 7 is a partial perspective view showing a main part of still another embodiment of the printing drum according to the present invention.

8 is a view of the structure shown in FIG. 7 viewed in the direction of arrow A in FIG.

FIG. 9 is a diagram showing another embodiment in the same manner as FIG.

FIG. 10 is a diagram showing still another embodiment in the same manner as in FIGS. 8 and 9.

FIG. 11 is a diagram showing still another embodiment in the same manner as in FIGS. 8 to 10.

[Explanation of symbols]

1 ... Printing drum 2 ... Backing roller 3 ... Medium press roller 4 ... pivot axis 5 ... Arm member 6 ... Gap 7 ... Printing paper feed roller 8 ... Printing paper 10a, 10b ... annular part 12 ... Yokokibe 12a, 12b ... Legs of cross bar 14 ... Stencil sheet starting edge attachment device 16 ... Axis 18 ... Flap 20 ... Flexible porous sheet 20a, 20b ... Both side edges of the flexible porous sheet 21a ... Edge of side edge portion 20a of flexible porous sheet 22a, 22b ... Gears 24 ... Starting end of flexible porous sheet 26 ... End of flexible porous sheet 28 ... Slit 29a ... One side wall of the slit 30 ... Guide pin 32 ... Hooking means 34 ... Plate member 36 ... Plate-shaped reinforcing member 38 ... Hook 40 ... hole 42a, 42b ... long holes 44a, 44b ... Guide pins 46a, 46b ... Snap disk 48a, 48b, 50a, 50b ... Claws 52a, 52b ... tension coil spring 54a, 54b ... Pedestal 56 ... Reinforcing piece for mounting 58 ... screw 59 ... Magnet piece 60 ... Locking part 61 ... Step 62 ... Tip 63 ... Locking member

─────────────────────────────────────────────────── ─── Continuation of the front page (72) The inventor, Nakata Takita, 2-20-15 Shimbashi, Minato-ku, Tokyo Ideal Science Co., Ltd. (56) References JP-A-3-197078 (JP, A) JP-A 3-254986 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41L 13/04

Claims (7)

(57) [Claims] 1. A printing drum comprising a cylindrical body having a porous structure for carrying a perforated stencil sheet in a wound state, and ink supplied from the inside of the cylindrical body extends along the inner surface of the cylindrical body. The stencil is pushed by the rolling middle push roller and is supplied to the stencil sheet through the hole of the cylinder body, and a part of the cylinder body is bulged outward in the radial direction by a predetermined substantial bulge by the middle push roller. A printing drum of a rotary type stencil printing apparatus which performs stencil printing on a printing paper pressed against the cylindrical body by a back-pressing means while the printing drum rotates while constituting both ends of the printing drum. A frame body including two annular portions and a cross-bar portion that connects the two annular portions and selectively attaches the starting end of the stencil sheet, and a cross member provided with a stencil sheet starting end attaching device; a starting end portion, an end portion, and both side edges; Have
Flexible porous sheet having a substantially rectangular expanded shape
And the both side edges are the outer peripheral surface of each of the two annular portions.
Cylindrical body that sits on top and is partially bulged outward in the radial direction
A flexible perforated sheet for forming a flexible drum, the starting end portion of the flexible perforated sheet is near the cross bar portion.
Is fixed to the frame body by the
Each extending substantially in the radial direction of the printing drum
Front of the two side walls and the outer side of the printing drum in the radial direction
The outside extending at least in part in the longitudinal direction of the printing drum.
And a peripheral guide wall, the end of the flexible porous sheet,
Between the two side walls and radially inward of the outer peripheral guide portion
By being slidably received by
Is substantially free to move along the outer peripheral surface and
Limited to lateral and radial offset of the printing drum
A printing drum characterized by being processed. 2. The printing drum of claim 1, wherein the flexible
The end of the porous sheet was opened in the circumferential direction of the cylinder.
With a long hole, the frame extends in the radial direction of the printing drum.
A printing drum including a guide pin that is present and engages the slot. 3. A printing drum, comprising a cylindrical body having a porous structure for carrying a perforated stencil sheet in a wound state, wherein ink supplied from the inside of the cylindrical body extends along the inner surface of the cylindrical body. The stencil is pushed by the rolling middle push roller and is supplied to the stencil sheet through the hole of the cylinder body, and a part of the cylinder body is bulged outward in the radial direction by a predetermined substantial bulge by the middle push roller. A printing drum of a rotary type stencil printing apparatus which performs stencil printing on a printing paper pressed against the cylindrical body by a back-pressing means while the printing drum rotates while constituting both ends of the printing drum. A frame body including two annular portions and a cross-bar portion that connects the two annular portions and selectively attaches the starting end of the stencil sheet, and a cross member provided with a stencil sheet starting end attaching device; a starting end portion, an end portion, and both side edges; Have
Flexible porous sheet having a substantially rectangular expanded shape
And the both side edges are the outer peripheral surface of each of the two annular portions.
Cylindrical body that sits on top and is partially bulged outward in the radial direction
And a flexible perforated sheet for forming a printing drum, wherein the starting end of the flexible perforated sheet is in the vicinity of the cross section.
It is fixed to the frame body and is attached to the end of the flexible porous sheet.
Is provided with a long hole extending in the circumferential direction of the cylindrical body,
The frame body protrudes outward in the radial direction from the frame body and projects into the elongated hole.
A guide pin that engages with the flexible porous sheath.
After being passed through the elongated hole at the end of the guide, the tip of the guide pin
Is locked to the end of the flexible porous sheet from the guide pin.
A retaining element to prevent the end from coming off.
As a result, the end portion of the flexible porous sheet has the annular portion.
Is held on the outer peripheral surface so that it can slide only along the outer peripheral surface.
A printing drum that is characterized by 4. The printing drum according to claim 3 , wherein the end portion of the flexible porous sheet includes a plate member connected to the main body of the flexible porous sheet by hooking means, and the elongated hole is A printing drum formed on the plate member. 5. In any one of the printing drum according to claim 1-4, wherein the flexible perforated sheet cylinder by elasticity of itself in a free state without being constrained both side edges by the two annular portions A printing drum, which is elastically curved in advance so as to be curled in a body forming direction. 6. In any one of the printing drum according to claim 1 to 5, wherein the stencil sheet leading end mounting device and the first rotational position for holding the starting end of the stencil sheet to the mounting position on the crossbar unit, wherein A flap that is selectively rotated between a second rotation position that is reversed from the first rotation position, and the flap is the end of the flexible porous sheet when the flap is in the second rotation position. A printing drum, wherein the printing drum is engaged with a portion to prevent movement of the end portion in the circumferential direction. 7. In any of the printing drum according to claim 1 to 5, the flexible perforated sheet end portions movement preventing device for selectively preventing movement of the circumferential end portion of the flexible perforated sheet The flexible perforated sheet end portion movement prevention device is flexible in conjunction with the fact that the stencil sheet starting end attaching device is brought to an operating position for holding the starting end of the stencil sheet at the attaching position on the cross bar portion. A printing drum, which releases the movement blocking action of the end portion of the porous sheet.