JP4673043B2 - Printing pressure application mechanism / printing device - Google Patents

Description

  In the present invention, a pressing member (press roller or the like) is moved only when necessary to press a sheet-like recording medium (printing paper) on the outer peripheral surface of the printing drum, and when not necessary, the pressing member is retracted from the printing drum. The present invention relates to a pressure applying mechanism and a printing apparatus such as a stencil printing apparatus having the printing pressure applying mechanism.

In the stencil printing apparatus, a press roller is provided outside the printing drum at a position facing an ink roller that is an element of ink supply means provided inside the printing drum. The press roller is moved to the printing drum side in accordance with the timing of the printing paper fed at a predetermined timing by the registration roller pair, and printing pressure is generated by pressing the printing paper with the press roller. The ink supplied from the ink oozes out from the perforated part of the printing drum and the perforated part of the pre-printed master wound around the outer peripheral surface of the printing drum, and is transferred to the printing paper.
The press roller is rotatably supported at one end of a swing arm (swing member) that is rotatably provided around a support shaft. The swing arm is always in a direction in which the press roller contacts the printing drum. It is biased by biasing means such as a spring.

A cam follower is provided on the other end side of the swing arm. By rotating the cam contacting the cam follower synchronously with the printing drum, the press roller repeatedly presses and retracts (separates) the printing drum alternately. . The cam has an eccentric convex portion, and when the cam follower rides on the eccentric convex portion, the press roller is most separated from the printing drum.
The press roller is pressed against the printing drum at the opening portion (image formable region) of the printing drum, and the press roller is separated from the printing drum at the non-opening portion (region where a clamper etc. for holding the master is provided). I have to.

In this type of printing pressure application mechanism, in addition to the above-described configuration, even if the cam surface of the cam is an area in which the pressing member is pressed against the printing drum, the engaging member that locks the swing arm so that the pressing member obtains a retracted state. A locking member and locking release means for releasing the locking of the locking member are provided.
During the printing operation as one job, the locking member remains unlocked. A solenoid is generally used as the unlocking means.
After the printing is finished, the swing arm and the locking member are locked by, for example, snap engagement by a contact displacement of the swing arm with respect to the locking member biased in one direction. .

Japanese Patent Laid-Open No. 10-119413

A certain amount of clearance (interval) is required for smooth engagement and unlocking between the swing member and the locking member. This is because the oscillating member is not displaced and locked linearly in the vertical or horizontal direction, but is formed by rotational displacement.
When the gap is too large, the swinging displacement of the swinging member due to the rotation of the cam accompanying the rotation of the printing drum during non-printing increases, and the impact sound due to the collision with the cam increases. If the gap is too small, depending on the printing speed, the stop operation of the swing member may not be in time, and the press roller may press in the absence of printing paper. Therefore, the dimension setting of the gap is very important.
This gap needs to be set in a state in which the cam follower of the swinging member rides on the maximum diameter portion of the cam, that is, in a state in which the press roller is most separated from the printing drum.
In this case, a configuration is conceivable in which the locking member is configured so as to be able to contact and separate with respect to the swinging member and fixed when a predetermined gap is secured.
To secure the gap, for example, a method is conceivable in which the locking member is pushed and fixed to the swinging member side through a jig such as a shim having a thickness corresponding to the gap, and then the shim is removed.

However, adjustment using a jig such as a thin-walled shim is delicate, and the gap obtained by the adjustment tends to vary depending on the operator and requires skill.
Further, since a spacer (such as a shim) for securing a gap is required, the management thereof is also necessary, and there is a problem that an appropriate gap cannot be set if it is not at hand.

  The present invention can easily and uniformly set a gap without using a member such as a shim and without requiring skill, and provides good locking and engagement between the swinging member and the locking member. An object of the present invention is to provide a printing pressure application mechanism capable of obtaining a stop release state and a printing apparatus having the printing pressure application mechanism.

In order to achieve the above object, in the first aspect of the present invention, a pressing member that is provided outside the printing drum and presses the sheet-like recording medium between the printing drum and the pressing member is rotatably held. At the same time, the swinging member is swingable about a support shaft and is constantly urged in the direction in which the pressing member contacts the printing drum, and the pressing member alternately presses and retracts with respect to the printing drum by rotation. The printing cam for operating the rocking member to repeat the above, and the pressing member so as to obtain a retracted state even if the cam surface of the printing pressure cam is a region that presses the pressing member against the printing drum. a locking member for locking the swing member, have a locking releasing means for releasing the locking of the locking member, the locking member is a clearance for engagement between said swinging member It is provided so that it can be adjusted. A part of the area where the member is held at the most retracted position from the printing drum is a reduced diameter area where the pressing member slightly approaches the printing drum, and the predetermined diameter of the swinging member with respect to the printing pressure cam is set in the reduced diameter area. the locking member in the printing pressure applying mechanism to set the clearance for locking is brought into contact with the engaging portion of the swinging member in abutting contact with abutting portion, the engaging member is, A stay fixed in a direction for adjusting a gap for locking with the swinging member, a stopper provided on the stay to be slidable in the adjusting direction and having a locking surface for the swinging member; A fixing means for fixing the stopper to the stay at an arbitrary position is provided.

According to a second aspect of the present invention, in the printing pressure applying mechanism according to the first aspect, there is provided an urging means that acts to return the stopper to the stay side in the sliding direction, and the locking surface of the stopper is oscillated. after contact by the biasing force of the biasing means to the locking portion of the rotary members, characterized that you fixed above the fixing means.

According to a third aspect of the present invention, in a printing apparatus that performs printing by moving the pressing member of the printing pressure application mechanism at a predetermined timing and pressing the sheet-like recording medium against the printing drum, the printing pressure application mechanism includes: It is characterized by being described in 1 or 2 .

According to a fourth aspect of the present invention, in the printing apparatus according to the third aspect, the adjusting means for automatically facing the predetermined contact portion of the swinging member with respect to the printing pressure cam to the reduced diameter region, and the automatic after adjustment. And an adjustment reset means for returning to the original state .

According to the first aspect of the present invention, a pressing member that is provided outside the printing drum and presses the sheet-like recording medium between the printing drum and the pressing member is rotatably held and centered on the support shaft. A swinging member that is swingable and is constantly biased in a direction in which the pressing member abuts on the printing drum, and the swinging member such that the pressing member alternately presses and retracts against the printing drum by rotation. A printing pressure cam that operates the moving member, and the swinging member is locked so that the pressing member is in a retracted state even in a region where the cam surface of the printing pressure cam presses the pressing member against the printing drum. a locking member that, have a locking releasing means for releasing the locking of the locking member, the locking member is provided so adjustable clearance for locking between said swinging member, Among the cam surfaces, the pressing member is replaced with the printing drum. A part of the area held at the most retracted position is a reduced diameter area where the pressing member slightly approaches the printing drum, and a predetermined contact portion of the swinging member with respect to the printing pressure cam is applied to the reduced diameter area. Since the locking member is brought into contact with the locking portion of the swinging member in the contacted state to set a clearance gap, a jig such as a shim can be used without skill. Can be easily adjusted without using a screw, and even an operator unfamiliar with the adjustment work can set an appropriate gap without variation, and the locking member can be locked with the swinging member. A stay fixed in a direction for adjusting a gap for the adjustment, a stopper provided on the stay to be slidable in the adjustment direction and having a locking surface for the swing member, and the stopper fixed to the stay at an arbitrary position Having fixing means to Since, it is possible to perform the adjustment work with a simple configuration.

According to a second aspect of the present invention, in the printing pressure applying mechanism according to the first aspect, there is provided an urging means that acts to return the stopper to the stay side in the sliding direction, and the locking surface of the stopper is provided. Since the urging force of the urging means is brought into contact with the locking portion of the swinging member and then fixed by the fixing means, the adjustment work can be further facilitated .

According to the invention of claim 3, in the printing apparatus that performs printing by moving the pressing member of the printing pressure applying mechanism at a predetermined timing and pressing the sheet-like recording medium on the printing drum, the printing pressure applying mechanism includes: Since it is the thing of Claim 1 or 2, it can obtain the effect of Claim 1 or 2 in a printing apparatus .

According to a fourth aspect of the present invention, in the printing apparatus according to the third aspect, the adjusting means for automatically causing the predetermined contact portion of the swinging member to the printing pressure cam to face the reduced diameter region, and after the adjustment Since the adjustment reset means for automatically returning to the original state is provided, the adjustment work can be semi-automated, which can be further facilitated and labor can be reduced .

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
First, based on FIG. 4, an overall configuration of a stencil printing apparatus as a printing apparatus in the present embodiment and an outline of a stencil printing process will be described.
A document reading unit 80 having an ADF function is provided in the upper part of the apparatus main body 50, and a printing drum unit 100 having a porous printing drum (plate cylinder) 101 is provided in the lower central part thereof. A plate making device 90 is provided on the upper right side of the printing drum unit 100, and a plate discharging device 70 is provided on the upper left side of the printing drum unit 100. In addition, a paper feeding device 110 is provided below the plate making device 90, a printing pressure unit 120 is provided below the printing drum unit 100, and a paper discharge unit 130 is provided below the plate discharging device 70.

Next, the printing operation of the stencil printing apparatus according to the above configuration will be described.
First, a document 60 having an image to be printed is placed on a document placing table (not shown) disposed at the top of the document reading unit 80, and a plate making start key on an operation panel (not shown) is pressed. Along with pressing of the plate making start key, a plate removing process is first executed. That is, in this state, the used heat-sensitive stencil master (hereinafter referred to as “used master”) 61b used in the previous printing remains attached to the outer peripheral surface of the printing drum 101 of the printing drum unit 100. Yes.

When the printing drum 101 rotates counterclockwise and the rear end portion of the used master 61b on the outer peripheral surface of the printing drum 101 approaches the plate release peeling roller pair 71a, 71b, the plate release peeling roller pair 71a, 71b is rotating. One discharge plate peeling roller pair 71a scoops up the rear end portion of the used master 61b.
The used master 61b is a pair of discharge plate conveying belts 72a and 72b wound around a pair of discharge plate rollers 73a and 73b disposed on the left side of the pair of discharge plate peeling rollers 71a and 71b and the pair of discharge plate peeling rollers 71a and 71b. While being transported in the direction of the arrow Y1, it is discharged into the discharge plate box 74 and is peeled off from the outer peripheral surface of the printing drum 101 to complete the discharge plate process. At this time, the printing drum 101 continues to rotate counterclockwise. The used master 61 b that has been peeled and discharged is then compressed inside the plate discharging box 74 by the compression plate 75.

In parallel with the plate removal process, the document reading unit 80 reads the document. A document 60 placed on a document table (not shown) is exposed and read while being conveyed in the directions of arrows Y2 to Y3 by the rotation of the separation roller 81, the pair of front document transport rollers 82a and 82b, and the pair of rear document transport rollers 83a and 83b. To be served. At this time, when there are a plurality of documents 60, the separation blade 84 feeds them one by one from the lowest document. In reading the image of the original 60, the reflected light from the surface of the original 60 illuminated by the fluorescent lamp 86 is reflected by the mirror 87 while being conveyed on the contact glass 85, and is constituted by a CCD (charge coupled device) through the lens 88. This is performed by being incident on the image sensor 89.
The original 60 is read by a well-known reduction-type original reading method, and the original 60 from which the image has been read is discharged onto the original tray 80A. The electrical signal photoelectrically converted by the image sensor 89 is input to an analog / digital (A / D) conversion board (not shown) in the apparatus main body 50 and converted into a digital image signal.

In parallel with this image reading operation, plate making and plate feeding processes are performed based on the image information converted into digital signals. A roll-shaped, non-plate-type heat-sensitive stencil master (hereinafter simply referred to as “master”) 61 set at a predetermined portion of the plate-making apparatus 90 is pulled out of the roll state and pressed by the thermal head 91 via the master 61. The platen roller 92 and the tension roller pair 93a and 93b rotate to be conveyed downstream of the conveying path.
A plurality of minute heating resistors arranged in a line on the thermal head 91 with respect to the master 61 transported in this way are each in response to a digital image signal sent from an A / D conversion board (not shown). The thermoplastic resin film of the master 61 that selectively generates heat and is in contact with the generated heating resistor is melt-pierced.
In this way, image information is written as a drilling pattern by position-selective melt drilling of the master 61 according to the image information.

  The leading end of the master-making master 61a on which image information has been written is sent out toward the outer peripheral side of the printing drum 101 by a pair of plate feeding rollers 94a and 94b, and the advancing direction is changed downward by a guide member (not shown). The printing drum 101 in the plate feeding position state hangs down toward the expanded master clamper 102 (indicated by a virtual line). At this time, the used master 61b has already been removed from the printing drum 101 by the plate discharging process.

  When the leading end of the master-making master 61a is clamped by the master clamper 102 at a fixed timing, the printing drum 101 gradually winds the master-making master 61a around the outer peripheral surface while rotating in the direction A (clockwise direction) in the figure. Go. The rear end portion of the master-making master 61a is cut into a fixed length by a cutter 95.

When one plate-made master 61a is wound around the outer peripheral surface of the printing drum 101, the plate-making and plate-feeding steps are finished, and the printing step is started. First, the uppermost one of the printing sheets 62 as the sheet-like recording medium stacked on the sheet feeding table 51 is sent out in the direction of arrow Y4 by the sheet feeding roller 140 toward the registration roller pair 142, and The registration roller pair 142 is sent to the printing pressure portion (image transfer portion) 120 at a predetermined timing synchronized with the rotation of the drum portion 100. When the fed printing paper 62 comes between the printing drum 101 and the press roller 103 as a pressing member, the press roller 103 that has been separated below the outer peripheral surface of the printing drum 101 is a printing pressure applying mechanism (see FIG. 4 is omitted), the plate making master 61a wound around the outer peripheral surface of the printing drum 101 is pressed.
In this way, ink oozes out from the opening portion of the printing drum 101 and the perforation pattern portion (both not shown) of the pre-printed master 61a, and the oozing ink is transferred to the surface of the printing paper 62 to form a printed image. Is done. The first printing after the plate feeding process may be referred to as printing.

On the inner peripheral side of the printing drum 101, ink is supplied from an ink supply pipe 104 to an ink reservoir 107 formed between the ink roller 105 and the doctor roller 106, in the same direction as the rotation direction of the printing drum 101, and Ink is supplied to the inner peripheral side of the printing drum 101 by an ink roller 105 that rolls in contact with the inner peripheral surface while rotating in synchronization with the rotation speed of the printing drum 101.
The press roller 103 is disposed outside the printing drum 101 at a position facing the ink roller 105.

The printing paper 62 on which a printing image is formed in the printing pressure unit 120 is peeled off from the printing drum 101 by the paper discharge peeling claw 114 and sucked by the suction fan 118, while the suction paper discharge inlet roller 115 and the suction paper discharge outlet roller. 116, the conveyance belt 117 wound around 116 rotates in the counterclockwise direction, is brought into close contact with the conveyance belt 117 and conveyed toward the sheet discharge unit 130 as indicated by an arrow Y5, and is sequentially discharged and stacked on the sheet discharge table 52. Is done. In this way, so-called trial printing is completed.
Next, when the number of prints is set with a numeric keypad (not shown) and a print start key (not shown) is pressed, the steps of paper feeding, printing and paper discharge are repeated for the set number of prints in the same process as the trial printing. All the processes of stencil printing are completed.

Before explaining the printing pressure application mechanism in the present embodiment, a reference example will be shown based on FIGS.
As shown in FIG. 7, the press roller 103 has an appropriate length according to the depth length (axial length) of the printing drum 101, and two end portions thereof are located on the near side and the far side. Is rotatably held in a hole 5a provided at one end portion of an L-shaped swing arm 5 as a swing member via a ball bearing (not shown).
The two swing arms 5 are rotatably supported by the apparatus main body 50 at the common swing center (support shaft) 3 in the same manner as the printing drum 101, and are swingable. One hook portion of a spring 7 as an urging means is hooked in the hole 5 c at the other end of the swing arm 5, and the other hook portion of the spring 7 is hooked on a shaft 8 provided in the apparatus main body 50. ing.
Therefore, the swing arm 5 is always urged clockwise about the support shaft 3, and when no external force is applied, the press roller 103 presses the outer peripheral surface of the printing drum 101 with a predetermined force. A so-called printing pressure is generated.

By this printing pressure, the printing paper 62 is fed between the printing drum 101 (strictly mastered master) and the press roller 103, so that the ink oozes out from the inside of the printing drum 101 and is transferred to the printing paper 62. Is formed.
A cam follower 5b composed of a ball bearing as a predetermined contact portion with respect to the printing pressure cam 4 described later is provided at a substantially central portion of the swing arm 5. In the vicinity of the cam follower 5b, the printing pressure cam 4 is supported so as to be rotatable about a shaft 6 supported by the apparatus main body 50, and is connected to a main body drive unit (not shown) so that an arrow at a predetermined rotational speed is obtained. It rotates in the 4a direction.
The printing pressure cam 4 is driven by the main body driving unit so as to be synchronized with the rotation speed of the printing drum 101.
When the printing pressure cam 4 rotates, the cam follower 5b of the oscillating arm 5 moves along the cam surface, which is the outer peripheral surface of the printing pressure cam 4, so that the oscillating arm 5 oscillates about the support shaft 3, as a result. The press roller 103 repeats the pressing position pressed against the printing drum 101 and the movement to the retracting position for retracting (separating) each time the printing drum 101 rotates once.

A locking member 30 that locks the swing arm 5 is provided below each swing arm 5. The locking member 30 includes a stay 10 that is rotatably supported around a shaft 11 provided in the apparatus main body 50, and a swing arm stopper 9 that is slidable in the longitudinal direction of the stay 10. Yes.
A hole 10 c is provided on the opposite side of the stay 10 to the swing arm stopper 9 side, and one hook portion of the stay return spring 13 is hung. The other hook portion of the stay return spring 13 is hung on a shaft 14 provided in the apparatus main body 50.
The swing arm stopper 9 slides so as not to come off by guide pieces 10b and 10b bent substantially vertically on both sides of the stay 10. The swing arm stopper 9 is formed with a long hole 9c extending in the sliding direction, and is fixed integrally with the stay 10 by a fixing screw 12 as a fixing means screwed to the stay 10 through the long hole 9c. It has become.
Once the fixing screw 12 is tightened, the oscillating arm stopper 9 is integrated with the stay 10 and is urged clockwise around the shaft 11, and hits the stay stopper 16 to maintain the position shown in FIG. .

In FIG. 7, a solenoid 15 is provided on the left side of the shaft 11 as an unlocking means. When the printing operation starts, energization of the solenoid 15 is started by a signal from a control unit (not shown) (for example, a main controller of the stencil printing apparatus), the plunger 15a moves downward by a predetermined amount, and comes into contact with the stay stopper 16 to be stationary. The operation | movement which pulls down the axis | shaft 10a which has connected the stay 10 and plunger 15a currently performed is performed.
The swing arm stopper 9 integrated with the stay 10 is rotated counterclockwise about the shaft 11, and the swing arm stopper 9 is retracted from the distal end portion 5 d as a locking portion of the swing arm 5. The state is temporarily fixed and maintained during the printing operation.
FIG. 8 shows a state where the solenoid 15 is energized and the swing arm stopper 9 is fixed at a position retracted from the distal end portion 5 d of the swing arm 5.
When the predetermined number of sheets have been printed, energization to the solenoid 15 is stopped at a predetermined timing by a stop signal from a control unit (not shown).

In general, the timing at which the energization is stopped is generally performed before the cam follower 5 b is positioned at the maximum diameter portion 4 c of the printing cam 4. This is because if the press roller 103 is not immediately positioned at the retracted position with respect to the print drum 101 after the printing is finished, the printing roller 62 is not present and the printing pressure acts again, and the press roller 103 is stained with ink. This is because when the cam follower 5b reaches the maximum diameter portion 4c of the printing cam 4, it is automatically locked (locking of the swing arm stopper 9 and the swing arm 5).
Here, the maximum diameter portion 4 c is an area where the press roller 103 is held at the most retracted position from the printing drum 101 on the cam surface of the printing pressure cam 4.

A mechanism for automatically locking immediately after the cam follower 5b reaches the maximum diameter portion 4c of the printing pressure cam 4 will be briefly described.
As described above, since the swing arm stopper 9 is integrated with the stay 10 and is urged clockwise about the shaft 11, when the energization to the solenoid 15 is stopped, the clock arm 9 is centered on the shaft 11. Try to rotate in the direction of rotation. However, until the cam follower 5b is positioned at the maximum diameter portion 4c of the printing cam 4, the tip portion 5d of the swing arm 5 is on the left side of the key portion 9b of the swing arm stopper 9, as shown in FIG. Therefore, the tip chamfered portion (C surface portion) 9 a of the swing arm stopper 9 comes into contact with the lower end chamfered portion (C surface portion) 5 e of the swing arm 5.
9 shows a state immediately before the energization of the solenoid 15 is stopped, the tip chamfered portion 9a of the swing arm stopper 9 is not yet in contact with the lower end chamfered portion 5e of the swing arm 5. .

Thereafter, as the cam follower 5b approaches the maximum diameter portion 4c of the printing cam 4, the lower end chamfered portion 5e of the swing arm 5 gradually climbs while sliding on the tip chamfered portion 9a of the swing arm stopper 9. Accordingly, the swing arm stopper 9 integrated with the stay 10 gradually rotates counterclockwise about the shaft 11 and swings when the cam follower 5b reaches the maximum diameter portion 4c of the printing cam 4. The distal end portion 5d of the moving arm 5 engages with the key portion 9b of the swing arm stopper 9, and at the same time, it is instantaneously rotated clockwise about the shaft 11 until the stay 10 contacts the stay stopper 16. The lock operation is completed.
That is, the tip 5 d of the swing arm 5 and the key portion 9 b of the swing arm stopper 9 are snap-fitted and engaged under the biasing force of the stay return spring 13.

Thereafter, in response to a stop signal from a control unit (not shown), the printing drum 101 is stopped at its home position at a predetermined timing, and at the same time, the printing pressure cam 4 is stopped to complete the printing operation. The printing pressure cam 4 is provided with a hole 4b corresponding to the home position of the printing drum 101. When the printing drum 101 is in the home position, the cam follower 5b is at a position facing the hole 4b.
When the cam follower 5b reaches the maximum diameter portion 4c of the printing cam 4, in order to smoothly lock (lock) or unlock the swing arm stopper 9, as shown in FIG. It is desirable to provide a predetermined gap G between the key portion 9 b of the arm stopper 9 and the tip portion 5 d of the swing arm 5.
Conventionally, the gap G is formed by loosening the fixing screw 12 with the cam follower 5b positioned at the maximum diameter portion 4c of the printing cam 4 during assembly or maintenance of the printing pressure application mechanism. A jig such as a shim having a thickness corresponding to the gap G is set between the key 9b and the tip 5d of the swing arm 5, and the swing arm stopper 9 is pushed toward the swing arm 5 to eliminate rattling. In this state, the fixing screw 12 is tightened again, and then the shim is removed.

For example, if the gap G is set larger by adjusting the gap G, the locking operation by the swing arm stopper 9 has a margin even if the cam follower 5b does not reach the maximum diameter portion 4c of the printing cam 4 sufficiently. Is possible.
However, if the gap G is too large, the printing cam 4 rotates in synchronization with the printing drum 101 when the printing drum 101 is rotated without applying printing pressure, such as an operation of supplying ink into the printing drum 101. For this reason, the cam follower 5b is greatly displaced in the clockwise direction around the swing center 3 of the swing arm 5 when the cam follower 5b is located outside the maximum diameter portion 4c of the printing cam 4. For this reason, the cam follower 5b rides on the printing cam 4 each time the printing cam 4 makes one rotation, and therefore noise and vibration of the swing arm 5 system are generated.
Therefore, in practice, the gap G depends on the positional relationship between the cam follower 5b and the swing arm stopper 9, but the adjustment work is performed so that the lock or unlock operation by the swing arm stopper 9 can be performed smoothly. In many cases, it was set to about 0.3 to 0.5 mm including variations.
However, the above adjustment work is very delicate due to its dimensional level, requires skill, and even when used, it is easy for operators to vary and it is difficult to set a uniform gap. there were.

The present invention aims to solve such problems.
Hereinafter, the gist of the present embodiment will be described with reference to FIGS. The same parts as those in the above-described reference embodiment are denoted by the same reference numerals, and unless otherwise specified, the description of the configuration and functions already described is omitted, and only the main parts will be described (the same applies to other embodiments below).
Compared to the configuration shown in FIG. 7, only the shape of the printing cam is different. Therefore, a series of operations of the apparatus is as described above.
A cam follower 5b composed of a ball bearing as a predetermined contact portion with respect to a cam 17 described later is provided at a substantially central portion of the swing arm 5. In the vicinity of the cam follower 5b, a printing pressure cam 17 is supported so as to be rotatable about a shaft 6 supported by the apparatus main body 50, and is connected to a main body drive unit (not shown) so that an arrow is formed at a predetermined rotational speed. It rotates in the direction 17a.
The printing pressure cam 17 is driven by the main body driving unit so as to be synchronized with the rotation speed of the printing drum 101.
When the printing pressure cam 17 rotates, the cam follower 5b of the oscillating arm 5 moves along the cam surface, which is the outer peripheral surface of the printing pressure cam 17, so that the oscillating arm 5 oscillates about the support shaft 3, as a result. The press roller 103 repeats the pressing position pressed against the printing drum 101 and the movement to the retracting position for retracting (separating) each time the printing drum 101 rotates once.

As in the above-described reference embodiment, the printing cam 17 is provided with a hole 17b corresponding to the home position of the printing drum 101. When the printing drum 101 is at the home position, the cam follower 5b is located at a position facing the hole 17b. It is comprised so that it may become.
Further, a hole 17d is provided adjacent to the hole 17b. Further, a reduced diameter region 17e which is a cam surface or a peripheral surface of a radius slightly smaller than the radius of the maximum diameter portion 17c is formed in a part of the maximum diameter portion 17c having the same shape as the maximum diameter portion 4c of the printing pressure cam 4. Is provided.
The diameter-reduced area 17e is an area where the press roller 103 slightly approaches the printing drum 101 more than the maximum diameter portion 17c, and is an adjustment area for setting the gap G. The difference in radius between the maximum diameter portion 17c and the reduced diameter region 17e is the dimension D.

FIG. 2 shows a state in which the printing cam 17 is superimposed on the printing cam 4. As is apparent from the figure, the upward and downward shapes of the printing cam 17 are the same as those of the conventional printing cam 4, and the shape of the reduced diameter region 17e slightly smaller than the maximum diameter portion 17c and The difference is that it has a hole 17d.
The dimension D is such that when the cam follower 5b is positioned in the reduced diameter region 17e of the printing cam 17, the gap between the key portion 9b of the swing arm stopper 9 and the tip portion 5d of the swing arm 5 becomes zero. Is set.
In other words, when the printing cam 17 is rotated so that the cam follower 5b is positioned in the reduced diameter region 17e, there is a gap between the key portion 9b of the swing arm stopper 9 and the tip portion 5d of the swing arm 5. If the cam follower 5b is positioned at the maximum diameter portion 17c by adjusting to zero and tightening the fixing screw 12, the key portion 9b of the swing arm stopper 9 and the tip portion 5d of the swing arm 5 are inevitably formed. Is a target dimension G that can be smoothly locked or unlocked by the swing arm stopper 9.

Therefore, if the cam surface of the printing pressure cam 17 including the reduced diameter region 17e slightly smaller than the maximum diameter portion 17c is designed so that the target gap G is, for example, 0.4 mm, an operator who is not accustomed to the adjustment work. Even so, it is possible to make adjustments easily and without variations without using a jig such as a shim.
The hole 17d adjacent to the hole 17b is provided as a guide for confirming that the cam follower 5b is located in the reduced diameter region 17e of the printing pressure cam 17. A mark (mark) may be formed instead of the hole 17b and the hole 17d.

When adjusting the gap G, the positioning of the cam follower 5b with respect to the reduced diameter region 17e of the printing pressure cam 17 may be automated (second embodiment).
Although not shown, in this embodiment, an adjustment key as an adjusting means is provided on the operation panel of the control unit. When the adjustment key is pressed, the cam follower 5b faces the hole 17d of the printing cam 17 when the adjustment key is pressed. The printing drum 101 and the printing pressure cam 17 are electrically driven to the position. For example, it can be made to oppose accurately by controlling the number of steps of the stepping motor of the main body drive unit (not shown) with the home position of the printing drum 101 as a reference.
After the automatic positioning is completed, the operator adjusts the swing arm stopper 9 and tightens the fixing screw 12 again.
After the adjustment is completed, when an adjustment reset key as an adjustment reset means provided on the operation panel is pressed, the control unit controls the printing drum 101 to return to the home position again. In this case, it is good also as an adjustment mode only for a service person.

A third embodiment will be described based on FIGS. 5 and 6.
In the first and second embodiments, when the cam follower 5b is positioned in the reduced diameter region 17e, the gap between the key portion 9b of the swing arm stopper 9 and the tip portion 5d of the swing arm 5 is zero. Thus, the operator needs to loosen the fixing screw 12 and lightly press the key portion 9b of the swing arm stopper 9 against the distal end portion 5d of the swing arm 5 with a finger or the like.
The purpose of this embodiment is to eliminate this annoyance. As shown in FIG. 5, a spring 18 is hung between a hole 9 d provided in a part of the swing arm stopper 9 and a hole 10 d provided in a part of the stay 10. A biasing force to return to the stay 10 side acts in the adjustment direction.
When adjusting the gap, simply loosen the fixing screw 12 and lightly press the key 9b of the swing arm stopper 9 and the tip 5d of the swing arm 5 with fingers (resulting in an appropriate butt force for obtaining the gap G). Automatically contact with the same force as).
After the operator loosens the fixing screw 12, the operator simply tightens the fixing screw 12 again. When the cam follower 5b is positioned at the maximum diameter portion 17c, the key portion of the swing arm stopper 9 is inevitably the same as described above. The gap between 9b and the tip 5d of the swing arm 5 has a target dimension G that can be smoothly locked or unlocked by the swing arm stopper 9.

Further, as described above, if the key portion 9b of the swing arm stopper 9 that is in contact with the distal end portion 5d of the swing arm 5 is intentionally fixed with a gap formed, the lock operation of the swing arm stopper 9 is performed. However, even if the maximum diameter portion 17c of the printing pressure cam 17 is not sufficiently reached, it can be made with a margin.
Although not shown, if the reduced diameter region 17e is separated from the other part of the printing pressure cam 17 and can be finely adjusted in the radial direction of the printing pressure cam 17, the cam follower 5b is positioned at the maximum diameter part 17c. In this state, the gap between the key portion 9b of the swing arm stopper 9 and the tip portion 5d of the swing arm 5 can be set smaller than the design value.

It is a general | schematic front view of the printing pressure provision mechanism before the adjustment in the 1st Embodiment of this invention. It is a superposition figure which shows the shape of a printing pressure cam. It is a general | schematic front view of the printing pressure provision mechanism at the time of completion of adjustment. 1 is a schematic front view of a stencil printing apparatus. It is a general | schematic front view of the printing pressure provision mechanism before adjustment in 3rd Embodiment. It is a general | schematic front view of the printing pressure provision mechanism at the time of completion of adjustment in 3rd Embodiment. It is a general | schematic front view of the conventional printing pressure provision mechanism. It is a general | schematic front view when operating the solenoid of the conventional printing pressure provision mechanism. It is a general | schematic front view of the printing pressure provision mechanism in the conventional printing operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Support shaft 4, 17 Printing pressure cam 5 Swing arm as a rocking member 9 Swing arm stopper as a stopper 9b Key part as a locking surface 10 Stay 15 Solenoid 15d as locking release means 15d As a locking part Tip portion 17e Reduced diameter region 18 Spring as urging means 30 Locking member 62 Printing paper as sheet-like recording medium 101 Printing drum 103 Press roller as pressing member

Claims (4)

A pressing member that is provided outside the printing drum and presses the sheet-like recording medium between the printing drum, the pressing member is rotatably held, and is swingable about a support shaft. A swinging member that is constantly biased in a direction in contact with the printing drum, and a printing pressure cam that operates the swinging member so that the pressing member alternately presses and retracts against the printing drum by rotation; A locking member that locks the swinging member so that the pressing member is in a retracted state even if the cam surface of the printing pressure cam is a region that presses the pressing member against the printing drum; and the locking member have a lock release means for releasing the locking,
The locking member is provided so that a gap for locking with the swinging member can be adjusted,
A part of the cam surface in which the pressing member is held at a position most retracted from the printing drum is defined as a reduced diameter area where the pressing member slightly approaches the printing drum, and the swinging movement is performed in the reduced diameter area. printing pressure applying mechanism the locking member being in contact with a predetermined contact site for the printing pressure cam member is brought into contact with the engaging portion of the swinging member to set the clearance for locking In
A stay in which the locking member is fixed in a direction for adjusting a gap for locking with the swing member, and a lock provided on the stay so as to be slidable in the adjustment direction. A printing pressure applying mechanism comprising: a stopper having a surface; and fixing means for fixing the stopper to the stay at an arbitrary position . In the printing pressure application mechanism according to claim 1,
There is a biasing means that acts to return the stopper to the stay side in the sliding direction, and the locking surface of the stopper is brought into contact with the locking portion of the swinging member by the biasing force of the biasing means. Thereafter, the printing pressure applying mechanism is fixed by the fixing means . In a printing apparatus that performs printing by moving a pressing member of a printing pressure applying mechanism at a predetermined timing and pressing a sheet-like recording medium on a printing drum,
3. A printing apparatus according to claim 1, wherein the printing pressure applying mechanism is the one according to claim 1 or 2 . The printing apparatus according to claim 3.
An adjusting means for automatically causing a predetermined contact portion of the swinging member with respect to the printing pressure cam to face the reduced diameter region, and an adjustment resetting means for automatically returning to the original state after the adjustment are provided. A printing device.

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