JP3880270B2 - Ink supply mechanism of printing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink supply mechanism of a printing apparatus that supplies a predetermined amount of ink to an inner peripheral surface of a plate cylinder using an ink supply roll and a doctor roll.
[0002]
[Prior art]
FIG. 5 is a partial configuration diagram of a printing unit of a conventional printing apparatus, and FIG. 6 is a sectional view showing an ink supply mechanism thereof. In these drawings, the stencil sheet 104 is drawn away from the screen 102 that forms the peripheral wall of the cylindrical plate cylinder in order to make the device configuration easy to understand. The base paper 104 is in close contact.
[0003]
5 and 6, the printing unit of the printing apparatus has a plate cylinder 100 and a paper cylinder 101, and the plate cylinder 100 and the paper cylinder 101 are respectively rotatable in a state in which a part of the outer peripheral surfaces of the printing cylinder 100 and the paper cylinder 101 are substantially close to each other. Is provided. On the outer peripheral surface of the plate cylinder 100, a base paper clamp portion 100a that clamps the leading end of the stencil base paper 104 is provided. A flexible screen 102 that forms the peripheral wall of the plate cylinder 100 is stretched on the outer peripheral surface of the plate cylinder 100, and the screen 102 is configured to pass the ink 103.
[0004]
An ink supply mechanism 105 is provided in the space inside the plate cylinder 100. The ink supply mechanism 105 has an ink supply roll 106, and this ink supply roll 106 is rotatably provided on a roll support member 107 (see FIG. 6). The ink supply roll 106 has a pressing position where the roll support member 107 is urged in the direction of arrow a in FIG. 6 and is pressed against the inner peripheral surface of the screen 102, and the roll support member 107 is in the direction of arrow b in FIG. It is configured to be able to change between a standby position separated from the inner peripheral surface of the screen 102. The ink supply roll 106 is in a pressing position during printing, and is in a standby position other than during printing. That is, the ink supply roll 106 also has a function of applying a printing pressure from the inner peripheral side of the screen 102.
[0005]
The roll support member 107 is supported so as to be rotatable about a support shaft 108. The roll support member 107 is provided with a doctor roll 109 and a drive rod 110, respectively. The doctor roll 109 has a cylindrical shape and is fixed to the roll support member 107 at a position close to the ink supply roll 106. The drive rod 110 is rotatably supported by the roll support member 107 and is disposed in an upper space formed by the outer peripheral surfaces of the ink supply roll 106 and the doctor roll 109 on the sides close to each other. Ink 103 is supplied to the upper space from an ink supply unit (not shown).
[0006]
Next, the outline operation of printing will be described in order. An outer periphery of the screen 102 that forms a hole at a predetermined position of the stencil sheet 104 and clamps the leading end of the stencil sheet 104 made by the stencil sheet 100 to form a peripheral wall of the plate cylinder 100. Wrap it around the surface. When a print start button (not shown) is pressed in this state, the plate cylinder 100 and the paper cylinder 101 are rotated in a direction indicated by an arrow in FIG. The ink supply roll 106 presses the screen 102, and the ink supply roll 106 rotates in synchronization with the plate cylinder 100 in this pressed state. Since the ink 103 is supplied to the outer peripheral surface of the ink supply roll 106 by the ink supply mechanism 105 as will be described in detail below, this rotation causes the inner peripheral surface of the screen 102 forming the peripheral wall of the plate cylinder 100 to rotate. Ink 103 is transferred. Further, the screen 102 bulges to the outer peripheral side by the pressing force of the ink supply roll 106, and the screen 102 is in pressure contact with the paper cylinder 101.
[0007]
In this state, as shown in FIG. 5, the printing paper 111 is conveyed between the plate cylinder 100 and the paper cylinder 101, and the printing paper 111 is continuously conveyed by the rotation of the plate cylinder 100 and the paper cylinder 101. The
[0008]
The printing paper 111 conveyed between the plate cylinder 100 and the paper cylinder 101 is conveyed while being pressed together with the screen 102 and the stencil sheet 104 between the ink supply roll 106 and the paper cylinder 101. The ink 103 on the screen 102 side is transferred to the printing paper 111 side from the hole of the stencil sheet 104 by this pressure contact force, and printing according to the stencil sheet 104 is performed.
[0009]
Next, the operation of the ink supply mechanism 105 will be described. When the ink 103 is supplied to the upper space from the ink supply unit, the ink 103 is agitated by the drive rod 110, and the ink 103 adhering to the outer peripheral surface of the ink supply roll 106 among the agitated ink 103 is Due to the adhesiveness, the ink supply roll 106 tries to rotate together. Then, those that cannot pass through the gap with the doctor roll 109 are separated from the outer peripheral surface of the ink supply roll 106, and only those that can pass through the gap continue to adhere to the outer peripheral surface of the ink supply roll 106. That is, by passing through the gap with the doctor roll 109, only a predetermined amount of the ink 103 always adheres to the ink supply roll 106 while forming a uniform ink film.
[0010]
By the way, even after the desired printing operation is completed, the state where the ink 103 is stored is maintained in the upper space between the ink supply roll 106 and the doctor roll 109 so that the next printing operation can be handled immediately. It has become.
[0011]
[Problems to be solved by the invention]
However, since there is a gap between the ink supply roll 106 and the doctor roll 109, there is a possibility that the ink 103 accumulated in the upper space leaks below the gap and falls on the inner surface of the screen 102 except during printing. In particular, it is likely to occur when the viscosity of the ink 103 to be used is low, or when the ink 103 is left unused for a long time and the ink viscosity is lowered due to a composition change.
[0012]
When the ink 103 hangs down on the inner peripheral surface of the screen 102 from the gap between the ink supply roll 106 and the doctor roll 109 except during printing, the drooped ink 103 flows on the inner peripheral surface of the screen 102. There was a problem of soiling the inside of the printing apparatus. Further, there is a problem that a large amount of ink adheres only to a part of the screen 102 due to the dripping ink 103, which causes uneven printing.
[0013]
Therefore, the present invention has been made to solve the above-described problems, and the dirt inside the printing apparatus caused by the ink leaking downward from the gap between the ink supply roll and the doctor roll at a time other than during printing. An object of the present invention is to provide an ink supply mechanism of a printing apparatus that can prevent uneven printing.
[0014]
[Means for Solving the Problems]
According to the first aspect of the present invention, a doctor roll is provided with a predetermined gap with respect to an ink supply roll which has an ink-permeable peripheral wall and is rotatably provided inside a plate cylinder which rotates around its own axis. The ink is supplied to an upper space constituted by the ink supply roll and the doctor roll, and a predetermined amount of ink is passed through the gap to the lower space side by the rotation of the ink supply roll. in the ink supply mechanism of a printing apparatus for supplying the inner peripheral surface of the plate cylinder through the supply roll, at the time of non-printing, the has an ink leakage preventing means for preventing the ink leakage out from the gap, the ink leakage The prevention means has a gap closing plug that closes the gap, and the blocking position that closes the gap from the lower space side. , Wherein said a configuration in which a movable between a release position for releasing the closed state of the gap.
[0015]
In the ink supply mechanism of this printing apparatus, ink leakage can be prevented by the ink leakage prevention means during non-printing. In the ink supply mechanism of the printing apparatus, the ink is supplied when the gap closing plug is set to the release position for releasing the closed state of the gap at the time of printing, and the gap closing plug is set to the closing position for closing the gap at the time of non-printing. There is no leakage below the gap formed between the roll and doctor roll .
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
<First Embodiment>
1 and 2 show a first embodiment of the present invention, FIG. 1 is a cross-sectional view showing a configuration of a printing unit of a stencil printing apparatus as a printing apparatus, and FIG. 2 is a cross-sectional view showing a configuration of ink leakage prevention means. is there.
[0022]
"Explanation of device configuration"
In FIG. 1, the printing unit includes a plate cylinder 1 and a paper cylinder 2, and the plate cylinder 1 and the paper cylinder 2 are rotatably provided in a state in which a part of each outer peripheral surface is substantially close to each other. On the outer peripheral surface of the plate cylinder 1, there is provided a base paper clamp portion (none of which is shown) for clamping the front end of the stencil base paper. A flexible screen (not shown) that forms the peripheral wall of the plate cylinder 1 is stretched on the outer peripheral surface of the plate cylinder 1, and this screen (not shown) is configured to pass the ink 3. An ink supply mechanism 4 for supplying ink 3 from the inner surface side of the screen is provided in the inner space of the plate cylinder 1, and this ink supply mechanism 4 is an ink leakage prevention means for preventing ink leakage from the gap described below. Twelve.
[0023]
The ink supply mechanism 4 has a pair of left and right roll support members 6 that rotate about a support shaft 5, and an ink supply roll 7 that is a squeegee roll is rotatably provided between the pair of roll support members 6. Yes. As shown in FIG. 1, the ink supply roll 7 is capable of rotating between a pressing position where the pressing state lowers the screen downward and a standby position separated from the inner peripheral surface of the screen. In addition, it is positioned at the standby position when not printing (other than during printing). That is, the ink supply roll 7 functions to supply the ink 3 to the inner peripheral surface of the screen forming the peripheral wall of the plate cylinder 1 and to apply a printing pressure to the screen.
[0024]
Further, a doctor roll 9 and a drive rod (not shown) are provided between the pair of roll support members 6. The doctor roll 9 has a cylindrical shape and is fixed to the roll support member 6 at a position close to the ink supply roll 7. The drive rod is rotatably supported by the roll support member 6 and is disposed in a wedge-shaped upper space constituted by the ink supply roll 7 and the doctor roll 9. Ink 3 is supplied from the ink supply unit 10 to the upper space, and an ink reservoir is formed in the upper space. The ink sensor 11 detects whether or not there is a predetermined amount of ink 3 in the ink reservoir, and ink is supplied from the ink supply unit 10 when the ink amount falls below a predetermined value.
[0025]
As shown in FIGS. 1 and 2, the ink leakage prevention means 12 has a lever 14 that is rotatably supported by a pair of left and right roll support members 6 around a support shaft 13. A gap closing plug 15 is integrally provided at the tip. The gap closing plug 15 is a closed position (indicated by the solid line in FIG. 2) that closes the gap between the ink supply roll 7 and the doctor roll 9 (the gap formed by these rolls 7 and 9) from the lower space side by the rotation of the lever 14. 2) and a release position (a position indicated by an imaginary line in FIG. 2) for releasing the closed state of the gap.
[0026]
One end of a tension spring 16 is hung on the other end of the lever 14 on the side opposite to the gap closing plug 15, and the gap closing plug 15 is biased toward the closing position by the spring force of the tension spring 16. A plunger 18 of a solenoid 17 is connected to the other end of the lever 14 so that the gap closing plug 15 can be moved to the release position side against the spring force of the tension spring 16 by the suction operation of the solenoid 17.
[0027]
"Description of operation"
Next, the outline operation of printing will be described in order. A perforated stencil sheet having a perforation formed at a predetermined location is wound around the outer peripheral surface of the screen of the plate cylinder 1, the ink supply roll 7 is in the standby position, and the gap closing plug 15 is moved by the spring force of the tension spring 16. Each is located at the closed position. When the print start button is pressed in this state, the plate cylinder 1 and the paper cylinder 2 are rotated in the direction indicated by the arrows in FIG. 1 and a drive signal is output to the solenoid 17 to attract the plunger 18. As a result, the gap closing plug 15 is moved to the release position against the spring force of the tension spring 16. As a result, the gap closed by the gap closing plug 15 is released. Further, the ink supply roll 7 is moved to the pressing position.
[0028]
When the ink supply roll 7 moves to the pressing position, the screen is pressed, and the ink supply roll 7 rotates in synchronization with the plate cylinder 1 in this pressed state. Ink 3 that has passed through a gap formed with the doctor roll 9 is attached to the outer peripheral surface of the rotating ink supply roll 7, and this ink 3 forms the inner peripheral surface of the plate cylinder 1. Is transferred to. Further, the screen bulges to the outer peripheral side by the pressing force of the ink supply roll 7, and the screen is brought into pressure contact with the paper cylinder 2.
[0029]
In this state, as shown in FIG. 1, the printing paper 20 is transported between the plate cylinder 1 and the paper cylinder 2, and a screen (not shown) is placed between the ink supply roll 7 and the paper cylinder 2. ) And the stencil sheet while being pressed. The ink 3 on the screen side is transferred to the printing paper 20 side from the hole of the stencil sheet by this pressure contact, and printing is performed according to the stencil sheet making.
[0030]
When the printing operation is completed, the rotation of the plate cylinder 1 and the paper cylinder 2 is stopped, and the ink supply roll 7 is moved to the standby position. Further, the drive signal to the solenoid 17 is stopped, and the gap closing plug 15 is moved to the closing position by the spring force of the tension spring 16. The closed state of the gap plug 15 is continued until the next printing operation starts.
[0031]
According to the first embodiment, the gap closing plug 15 closes the gap between the ink supply roll 7 and the doctor roll 9 during non-printing, so that the ink 3 does not leak below the gap, and printing due to ink leakage occurs. It is possible to prevent stains and uneven printing inside the device. That is, the ink 3 is prevented from leaking below the gap when the viscosity of the ink 3 to be used is low or when the ink 3 is left unused for a long time and the ink viscosity is lowered due to a composition change. it can.
[0032]
Further, according to the first embodiment, since the gap closing plug 15 is in the closing position by the spring force of the tension spring 16 when not printing, it is not necessary to supply power to the solenoid 17 except during printing. Can be suppressed as much as possible.
[0033]
Second Embodiment
Next, a second embodiment of the present invention will be described with reference to the drawings.
[0034]
3 and 4 show a second embodiment of the present invention, FIG. 3 is a cross-sectional view showing a configuration of a printing unit of a stencil printing apparatus as a printing apparatus, and FIG. 4 is a cross-sectional view showing a configuration of ink leakage prevention means. is there. 3 and 4, the second embodiment is different from the first embodiment only in the configuration of the ink leakage prevention means 12, and the other components are the same. The same reference numerals are attached to the drawings and the description thereof is omitted, and only the configuration of the different ink leakage prevention means 12 will be described.
[0035]
"Explanation of device configuration"
That is, the ink leakage prevention means 12 is configured such that the support shaft 9a of the doctor roll 9 is fixed at an eccentric position shifted from the center position of the doctor roll 9, and the doctor roll 9 is paired with a pair of roll support members by the eccentric support shaft 9a. 6 is supported. That is, the rotation of the support shaft 9 a causes the doctor roll 9 to come into contact with the ink supply roll 7 to eliminate the gap (the position indicated by the solid line in FIG. 4), and a predetermined gap from the ink supply roll 7. It is configured to be movable between a position with a gap (the position of an imaginary line in FIG. 4).
[0036]
In the present specification, the position of the doctor roll 9 without a gap includes not only the position in close contact with the ink supply roll 7 but also the position that is sufficiently close to the ink supply roll 7 and does not leak the ink 3. It is.
[0037]
A worm wheel 21 is fixed to the support shaft 9 a of the doctor roll 9, and a worm gear 22 is engaged with the worm wheel 21. The worm gear 22 is fixed to a rotating shaft of a stepping motor 23, and the stepping motor 23 is configured such that the drive is controlled by a controller.
[0038]
"Description of operation"
Next, the outline operation of printing will be described in order. Perforated stencil sheets with perforations formed at predetermined locations are wound around the outer peripheral surface of the screen of the plate cylinder 1, the ink supply roll 7 is positioned at a standby position, and the doctor roll 9 is positioned at a position without a gap. ing. When the print start button is pressed in this state, the plate cylinder 1 and the paper cylinder 2 are rotated in the direction indicated by the arrows in FIG. And the doctor roll 9 is moved to a position with a gap. As a result, the gap closed by the doctor roll 9 is released. Further, the ink supply roll 7 is moved to the pressing position.
[0039]
When the ink supply roll 7 moves to the pressing position, the screen is pressed, and the ink supply roll 7 rotates in synchronization with the plate cylinder 1 in this pressed state. Ink 3 that has passed through a gap formed with the doctor roll 9 is attached to the outer peripheral surface of the rotating ink supply roll 7, and this ink 3 forms the inner peripheral surface of the plate cylinder 1. Is transferred to. Further, the screen bulges to the outer peripheral side by the pressing force of the ink supply roll 7, and the screen is brought into pressure contact with the paper cylinder 2.
[0040]
In this state, as shown in FIG. 3, the printing paper 20 is conveyed between the plate cylinder 1 and the paper cylinder 2, and together with the screen and the stencil sheet between the ink supply roll 7 and the paper cylinder 2. It is conveyed while being pressed. The ink 3 on the screen side is transferred to the printing paper 20 side from the hole of the stencil sheet by this pressure contact, and printing is performed according to the stencil sheet making.
[0041]
When the printing operation is completed, the rotation of the plate cylinder 1 and the paper cylinder 2 is stopped, and the ink supply roll 7 is moved to the standby position. Further, a drive signal is output to the stepping motor 23 and driven by a predetermined number of steps, and the doctor roll 9 is moved to a position without a gap. As a result, the doctor roll 9 comes into close contact with the ink supply roll 7 and the gap is closed. The state without gaps of the doctor roll 9 is maintained until the next printing operation starts.
[0042]
According to the second embodiment, the doctor roll 9 abuts on the ink supply roll 7 and eliminates the gap during non-printing, so that the ink 3 does not leak downward, and stains inside the printing apparatus caused by ink leakage can be prevented. Printing unevenness can be prevented.
[0043]
Moreover, according to this 2nd Embodiment, since the doctor roll 9 can be moved to the ink supply roll 7 in the contact / separation direction, gap adjustment is possible. Further, since the doctor roll 9 is moved by the stepping motor 23, the step rotation speed of the stepping motor 23 and the moving distance of the doctor roll 9 are proportional to each other, so that the gap adjustment can be easily performed.
[0044]
Further, according to the second embodiment, since the worm wheel 21 and the worm gear 22 are provided in the rotation transmission system of the stepping motor 23, electric power is used to hold the doctor roll 9 at a position with a gap or a position without a gap. It is not consumed and no separate holding means is required.
[0045]
<Other embodiments>
According to the second embodiment, the support shaft 9a of the doctor roll 9 is arranged at the eccentric position of the doctor roll 9, and the doctor roll 9 is moved to a position with and without a gap by using this eccentricity. Although configured, the doctor roll 9 may be configured by means other than eccentricity as long as the doctor roll 9 can move between a position without a gap and a position with a gap with respect to the ink supply roll 7.
[0046]
Moreover, although the case where the present invention is applied to an inner press type stencil printing apparatus in which printing pressure is applied from the inner peripheral side of the screen has been shown, an outer press type stencil printing apparatus in which printing pressure is applied from the outer peripheral side of the screen, Alternatively, the present invention can be applied to an apparatus in which both are moved and pressed.
[0047]
Moreover, although the case where this invention was applied to the stencil printing apparatus was shown, it is applicable also to printing apparatuses other than a stencil.
[0048]
In the above-described embodiment, the present invention shows the case of a printing apparatus that prints an image by pressing the printing paper 20 against the stencil sheet mounted on the plate cylinder 1. However, the stencil sheet mounted on the plate cylinder 1 is described. The present invention can also be applied to a printing apparatus that presses a transfer cylinder onto the transfer cylinder, temporarily transfers ink to the transfer cylinder, and presses the printing paper 20 on the transfer cylinder to print an image.
[0049]
Further, in each of the above-described embodiments, the present invention is applied to an inner press type stencil printing apparatus, and the ink supply roll 7 is used both as a means for applying a printing pressure to the screen and a means for supplying the ink 3. However, the structure which provides separately the roll which provides printing pressure, and the roll which supplies ink may be sufficient.
[0050]
【The invention's effect】
As described above, according to the first aspect of the present invention, the doctor roll is attached to the ink supply roll that is rotatably provided inside the plate cylinder that has an ink-permeable peripheral wall and rotates about its own axis. A predetermined gap is provided, ink is supplied to an upper space constituted by the ink supply roll and the doctor roll, and a predetermined amount of ink is passed through the gap to the lower space side by rotation of the ink supply roll. In the ink supply mechanism of the printing apparatus for supplying the ink to the inner peripheral surface of the plate cylinder via the ink supply roll, the ink leakage prevention means for preventing the ink from leaking downward from the gap when not printing. In case of non-printing, ink leakage can be prevented by means of ink leakage prevention. La can be prevented.
Further, according to the present invention, the ink leakage prevention means releases the gap closing plug, the closing position where the gap formed between the ink supply roll and the doctor roll is closed from the lower space side, and the closed state of the gap. Since the gap closing plug is set to the release position during printing and the gap closing plug is set to the closing position when not printing, the ink does not leak below the gap. It is possible to prevent stains and uneven printing inside the printing apparatus due to leakage .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a configuration of a printing unit of a stencil printing apparatus according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a configuration of ink leakage prevention means according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view illustrating a configuration of a printing unit of a stencil printing apparatus according to a second embodiment of the present invention.
FIG. 4 is a cross-sectional view showing a configuration of ink leakage prevention means according to a second embodiment of the present invention.
FIG. 5 is a partial configuration diagram of a printing unit of a conventional printing apparatus.
FIG. 6 is a cross-sectional view of a conventional ink supply mechanism.
[Explanation of symbols]
3 Ink 4 Ink supply mechanism 7 Ink supply roll 9 Doctor roll 12 Ink leakage prevention means 15 Gap closing plug

Claims (1)

A doctor roll is provided with a predetermined gap with respect to an ink supply roll that is rotatably provided inside a plate cylinder that has an ink-permeable peripheral wall and rotates around its own axis, and the ink supply roll and the ink supply roll Ink is supplied to an upper space constituted by a doctor roll, a predetermined amount of ink is passed through the gap to the lower space side by the rotation of the ink supply roll, and the ink is supplied to the plate cylinder via the ink supply roll. In the ink supply mechanism of the printing apparatus that supplies the inner peripheral surface of
Having ink leakage prevention means for preventing ink from leaking out of the gap during non-printing;
The ink leakage prevention means has a gap closing plug that closes the gap, and the gap closing plug is between a closing position that closes the gap from the lower space side and a release position that releases the closing state of the gap. An ink supply mechanism of a printing apparatus, characterized by being configured to be movable.

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