JPH11129600A - Phase regulating mechanism for printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a so-called ghost phenomenon by preventing a phase deviation during printing due to a long timing belt by phase regulating by using the belt for interlocking a plate cylinder of an upstream side to a plate cylinder of a downstream side. SOLUTION: A driving shaft 6 of a plate cylinder of a downstream side is in a non-fixed state with a pulley 8 fixed to a cylindrical member 24 rotatably supported to a side plate 28. A slider 26 axially moved to the shaft 6 by a regulating means 12 of a feeding thread type is provided in the member 24. An oblique long hole 14 inclined to an axial direction of the shaft 6 is formed at the slider 26. And, an engaging pin 16 to be engaged with the hole 14 is fixed to the shaft 6. An engaging position of the hole 14 with the pin 16 is changed due to a movement of the slider 26. Thus, a rotating position of the shaft 6 to the pulley 8 (a phase to a plate cylinder of an upstream side) is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase adjusting device in a printing apparatus such as a multicolor stencil printing apparatus.

[0002]

2. Description of the Related Art For example, in a multicolor stencil printing apparatus for simultaneously performing multicolor printing, a plurality of color-specific plate cylinders are arranged at intervals in a conveying direction of printing paper, and the outer peripheral surface of each plate cylinder is provided. By continuously pressing the printing paper against the wound master, the plate-making image formed on each master is transferred. A pulley is attached to a drive shaft (rotary shaft) of each plate cylinder, and a timing belt stretched between the pulleys causes an upstream plate cylinder in a printing paper transport direction (also called a top-to-bottom direction). And the rotation timing of the plate cylinder on the downstream side.

In such a double-cylinder printing apparatus, since the plate cylinders are provided at intervals in the direction in which the printing paper is conveyed, a downstream plate is required to correct the image position shift due to the separation distance. The image of the cylinder is transferred with a rotational phase difference to the image of the plate cylinder on the upstream side. If the rotational phase difference between the upstream plate cylinder and the downstream plate cylinder is properly determined at the time when the timing belt is stretched, and there is no problem if this is maintained unchanged after that, there is no problem in the manufacturing stage. Phase shift is likely to occur due to factors such as dimensional shifts over time and the configuration. For this reason, many printing apparatuses of this type are provided with a phase adjusting mechanism for adjusting a phase shift. As a phase adjustment mechanism, for example, a mechanism described in Japanese Patent Application Laid-Open No. 7-17121 is known.

This phase adjusting mechanism is, as shown in FIG.
A pulley 100A fixed to the drive shaft of the upstream plate cylinder,
A pulley 100B fixed to the drive shaft of the plate cylinder on the downstream side,
Movable pulleys 100C and 100D that can be simultaneously moved in a direction perpendicular to the transport direction of the printing paper, a timing belt 102 stretched between these pulleys, and four tensions for applying tension to the timing belt 102 And an idler 104. The movable pulleys 100C and 100D are connected by a slider (not shown), and are simultaneously moved up and down by moving the slider up and down by driving a pinion gear (not shown) meshing with a rack portion of the slider. For example, with the upstream plate cylinder locked, the movable pulley 100C, 1
When 00D is moved upward, the pulley 100B rotates in the direction of the arrow, and by adjusting the amount of rotation, it is possible to adjust the deviation of the rotational phase difference between the downstream plate cylinder and the upstream plate cylinder.

[0005]

In the conventional phase adjusting mechanism described above, the movable pulley is provided in addition to the original length of the timing belt 102 for simultaneously driving the upstream plate cylinder and the downstream plate cylinder. Since the length for adjusting at 100C and 100D is necessary, the entire timing belt 102 is very long.

Since the timing belt 102 is formed of a material having an elongation ratio with respect to tension due to its use property, the longer the length, the greater the elongation. As described above, since the tension is always applied to the timing belt 102, the conventional phase adjustment mechanism has a problem that the timing belt 102 is easily stretched. If the elongation of the timing belt 102 is large, a shift in the rotational phase difference between the plate cylinders occurs during printing, resulting in a shift in the image position and doubles. Also, when the image position is shifted due to the difference in the rotational phase difference between the plate cylinders, the image of the upstream plate cylinder adhering to the master surface of the downstream plate cylinder shifts in the transfer on the next printing paper, a so-called ghost phenomenon. There is a problem that causes.
Further, in the above-described conventional phase adjustment mechanism, since the phase is adjusted by operating the timing belt 102, a large load is applied to the drive shaft of the plate cylinder, so that the drive source capacity of the phase adjustment mechanism is increased and power consumption is reduced. There was a problem of increasing.

Accordingly, an object of the present invention is to provide a phase adjusting mechanism in a printing apparatus which can eliminate the above-mentioned problems caused by the timing belt.

[0008]

Since the upstream plate cylinder is used as a reference in image alignment, only the downstream plate cylinder adjacent to the upstream plate cylinder is subject to phase adjustment. Based on the idea that the phase adjustment is performed by a timing belt which is an existing component, it can be said that the above problems are caused. Under such recognition, the present invention has decided to perform the phase adjustment with a configuration relating only to the downstream plate cylinder.

Specifically, according to the first aspect of the present invention, the drive shaft of the plate cylinder and the pulley are provided in a non-fixed state, and the drive shaft and the pulley are provided on one of the drive shaft side and the pulley side. A slanted oblong hole formed and positioned obliquely with respect to the axial direction of the drive shaft, an engaging pin provided on the other side and engaged with the oblique oblong hole, and an engaging position between the oblique oblong hole and the engaging pin And a connecting member for connecting the drive shaft side and the pulley side to rotate synchronously with each other.

According to the second aspect of the present invention, the upstream and downstream plate cylinders in the printing paper transport direction are interlocked by a timing belt between pulleys provided on the respective drive shafts. A phase adjusting mechanism that is used in a multi-cylinder printing apparatus that performs simultaneous printing by transferring each image of the plurality of plate cylinders to printing paper, and that adjusts a position shift of a print image between the plate cylinders in a printing paper transport direction. The drive shaft and the pulley of the downstream plate cylinder are provided in a non-fixed state with each other, and are formed on one of the drive shaft side and the pulley side in the axial direction of the drive shaft. An oblique hole positioned obliquely with respect to the engaging hole, an engaging pin provided on the other side and engaged with the oblique elongated hole, adjusting means for changing an engaging position between the oblique oblong hole and the engaging pin, Connect the drive shaft side and pulley side to That the connecting member is provided with a, it adopts a configuration that.

According to a third aspect of the invention, in the configuration of the second aspect, the adjustment means has a feed screw configuration.

According to a fourth aspect of the present invention, in the configuration of the third aspect, the adjustment means has a rotation amount detection means for controlling the adjustment amount.

According to a fifth aspect of the present invention, in the configuration of the second, third or fourth aspect, the engagement pin also serves as the connection member.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, a configuration of a multicolor stencil printing apparatus as an example to which the phase adjusting mechanism in the double-cylinder printing apparatus according to the present invention is applied will be briefly described with reference to FIG. The multicolor stencil printing apparatus includes detachable printing drums 60 and 62, a plate making device 64 disposed near the right side of the printing drum 60, and a sheet feeding device 66 disposed below and to the right of the printing drum 60. , A plate discharging device 68 disposed near the left side of the printing drum 62, a registration roller pair 70, press rollers 72 and 74 disposed below the printing drums 60 and 62, and a printing drum 6.
Separation claws 76 and 78 disposed near the printing drums 60 and 62, an intermediate conveyance device 80 disposed between the printing drums 60 and 62,
A sheet discharging and conveying device 82 disposed at the lower left of the printing drum 62
, A paper ejection tray 84, and a document reading section 86 provided on the upper surface of the apparatus main body. A pulley 4 is fixed to a drive shaft 2 of a printing drum 60 as an upstream plate cylinder, and a drive shaft 6 of a printing drum 62 as a downstream plate cylinder.
Is provided with a pulley 8. A timing belt 10 is stretched around the pulley 4 and the pulley 8 so that the printing drum 60 and the printing drum 62 are linked at the same peripheral speed.

Next, the printing process of the multicolor stencil printing machine will be described. First, the used master wound around the print drum 62 is removed by the plate discharging device 68. afterwards,
The printing drums 60 and 62 are exchanged, and the plate making device 64 supplies a plate to the printing drum 62. Plate making device 64
Then, a thermal head (not shown) is driven based on the read information of the document reading section 86, and perforating the master is performed. The master that has been made is wound around the outer surface of the printing drum 62. When the plate supply to the printing drum 62 is completed, the plate discharging device 68 discharges the printing drum 60. The print drums 60 and 62 are replaced again, and the plate making device 64 supplies the plate to the print drum 60.

When the plate feeding to the printing drums 60 and 62 is completed, the printing paper P on the paper feeding tray 88 in the paper feeding device 66 is fed by the feeding roller 90 and the upper separating roller 9
The sheets are separated one by one and fed by the lower separation roller 94. Thereafter, the printing paper P is fed to the nip portion between the press roller 72 and the printing drum 60 after being timed by the registration roller pair 70 with the printing drum 60 on the upstream side. As a result, an image of the color (for example, black) assigned to the print drum 60 is printed on the printing paper P.

The printing paper P on which the black image is formed is separated from the master surface of the printing drum 60 by the separation claw 76, and proceeds to the intermediate conveyance device 80 located downstream. The printing paper P conveyed by the intermediate conveyance device 80 is sent to a nip portion between the printing drum 62 and the press roller 74 on the downstream side. As a result, an image of the color (for example, red) assigned to the print drum 62 is printed on the printing paper P. The printing drum 60 and the printing drum 62 are rotated at the same peripheral speed by the timing belt 10 as described above, but the image position transferred to the printing drum 62 is
The phase shift needs to be corrected to be the same as above. The phase adjustment mechanism corrects this phase shift, and is provided only for the print drum 62 on the downstream side.

This phase adjusting mechanism, as shown in FIG.
An adjusting means 12 of a feed screw type, an oblong slot 14 formed in a member on the pulley 8 side, an engaging pin 16 fixed to the drive shaft 6 and engaging with the oblong slot 14, It mainly comprises a connecting pin 18 as a connecting member for synchronously rotating the pulley 8 side. The drive shaft 6 is held by a bearing (not shown) on the left side of FIG. 1, and is rotatable in the circumferential direction but does not move in the axial direction. The drive shaft 6 is integrally fixed with the printing pressure cam 22 for controlling the operation of moving the press roller 74 toward and away from the printing drum 62. As shown in FIG. 2, after the drive shaft 6 is inserted into the slider 26, the engagement pin 16 is driven into the pin housing hole 6 a formed in the drive shaft 6 from outside the oblong slot 14 and fixed. As shown in FIG. 1, the pulley 8 side includes a pulley 8, a cylindrical member 24 to which the pulley 8 is fixed, and a cylindrical slider 2 movably provided in the cylindrical member 24.
The cylindrical member 24 is rotatably supported at one end side (the adjusting means 12 side) on a side plate 28 of the apparatus main body via a bearing 30. Tube member 24 and slider 2
6 is configured to rotate synchronously by a connecting pin 18 as a connecting member, and the connecting pin 18 is allowed to move in the axial direction of the drive shaft 6 by an elongated hole 20 formed in the cylindrical member 24.

As shown in FIG. 2, the oblong slot 14 is formed on the cylindrical side surface of the slider 26 so as to be oblique to the axial direction of the drive shaft 6. The connecting pin 18 is press-fitted into holes 26a and 26b formed above and below the slider 26 and fixed. The length of the connecting pin 18 is the slider 26
, The upper and lower protruding portions of which are inserted into the elongated holes 20. The elongated hole 20 is formed above and below the cylindrical member 24 along the axial direction of the drive shaft 6.

As shown in FIG. 1, the adjusting means 12 includes a motor 34 supported on the side plate 32, a driving gear 36 fixed to a rotating shaft of the motor 34, and a meshing The driven gear 38 mainly includes a large-diameter driven gear 38 having an internal thread portion, and an adjusting member 40 having a screw portion 40 a that is screwed into the internal thread portion of the driven gear 38. One end of the adjusting member 40 is rotatably fitted to the bottom of the slider 26, and a large-diameter portion 40b is formed at one end thereof. The large-diameter portion 40b is accommodated in an accommodation hole 26c formed in the slider 26. , Are prevented from coming off by the connecting pins 18. A detent pin 42 is fixed to the other end of the adjustment member 40, and the detent pin 42 is guided by a detent guide 44 fixed to the side plate 32 (FIG. 3). The driven gear 38 is the side plate 3
2, and is restricted by the side plate 46 from moving toward the drive shaft 6.

The adjusting means 12 has a rotation amount detecting means 48 for controlling the moving amount of the adjusting member 40. In the present embodiment, the rotation amount detecting means 48 includes a side plate 46.
And the driven gear 38
And a dog 50 that is fixed to the outer peripheral end of the photo interrupter 49 and blocks between the light emitting unit and the light receiving unit of the photo interrupter 49. In FIG. 1, reference numeral 52 denotes a flange that regulates the displacement of the timing belt 10.

Next, a description will be given of a phase adjusting operation by the above-described phase adjusting mechanism. When the motor 34 rotates, the driving gear 36
And the driven gear 38 rotates. When the driven gear 38 rotates, the adjusting member 40 moves in the axial direction (left-right direction) of the drive shaft 6 depending on the rotation direction. For example, when the motor 34 is rotated so that the adjustment member 40 moves to the left, the slider 26 is pressed by the adjustment member 40 and moves to the left inside the tubular member 24. In this case, the engagement pin 16 is guided by the movement of the oblong slot 14 formed in the slider 26.
As shown in FIG. 4 (a), the center position is displaced from the S ₁ to S _2. Accordingly, the rotation of the drive shaft 6 corresponding to the displacement e is obtained. By adjusting the amount of displacement, the rotational position of the drive shaft 6 with respect to the pulley 8 (the phase with respect to the plate cylinder on the upstream side) can be arbitrarily shifted. In the case of FIG. 4A, the engagement pin 16 is
, The drive shaft 6 rotates leftward when viewed from the L side. When the phase is adjusted, the pulley 8 is loaded by the belt 10 so that the pulley 8 and the cylindrical member 24 do not rotate.

In the rotation after the phase adjustment, the drive shaft 6 and the slider 26 are connected by the engagement pin 16 and
Since the slider 26 and the tubular member 24 are connected by the connecting pin 18, the drive shaft 6 and the pulley 8 rotate synchronously. In this case, since the movement of the slider 26 in the axial direction is prevented by the adjusting member 40 and the connecting pin 18, the engaging position between the oblong slot 14 and the engaging pin 16 does not shift, and no phase shift occurs. In addition, instead of the connecting pin 18 and the elongated hole 20,
A groove extending in the axial direction of the drive shaft 6 may be formed in one of the cylindrical member 24 and the slider 26, and a protrusion may be provided in the other in engagement with the groove.

FIG. 4B shows the phase adjustment when the adjustment member 40 is moved to the right. In this case,
The drive shaft 6 rotates rightward when viewed from the L side.

When the image position is shifted as a result of printing, an adjustment amount is instructed by an operator via an operation panel of a multicolor stencil printing machine (not shown). The control means of the multicolor stencil printing machine (not shown) controls the motor 34 based on the adjustment amount. Specifically, the control means stores the relationship data between the adjustment amount obtained in advance and the rotation speed of the motor 34 in the RO
M, and the number of rotations of the motor 34 corresponding to the adjustment amount is determined. The number of rotations of the motor 34 is
Is counted based on the detection signal from.

The phase adjusting mechanism according to the present embodiment corresponds to only the downstream printing drum 62 and the upstream printing drum 6.
0 has no effect on the structure at all, so that the timing belt 10 can be short and simple as shown in FIG. In FIG. 5, reference numeral 54 denotes a tension pulley.

Next, FIGS. 7 and 8 show another embodiment.
The same parts as those in the above embodiment are denoted by the same reference numerals, and the description of the configuration or function will be appropriately omitted. The drive shaft 7 in this embodiment is formed in a hollow shape as shown in FIG. 7, and the inside of the drive shaft 7 is provided with an adjusting member 40 as in the above embodiment.
Is moved. The engagement pin 17 is fixed to the slider 27,
The engagement pin 17 is provided on the inclined oblong hole 15 formed in the pulley 9.
, And the inclined slot 15 has the same function as the slot 20 in the above embodiment. The engagement pin 17 also serves as the connection pin 18 in the above embodiment, and the drive shaft 7 has the same function as the inclined oblong hole 14 in the above embodiment, that is, moves along with the movement of the engagement pin 17 during adjustment. A long hole 21 is formed. The elongated hole 21 is formed so as to be inclined to the side opposite to the inclined elongated hole 15 as shown in FIG. In FIG. 7, reference numeral 19 denotes a collar, and reference numeral 23 denotes a retaining ring. In this embodiment, as shown in FIG. 7, the movement of the driven gear 38 is restricted between the side plate 32 and the end face of the drive shaft 7.

As shown in FIG. 8A, when the adjusting member 40 is adjusted to move to the left, the engaging pin 17 is guided by the oblong slot 15 and the center position is changed from S ₁ to S ₂ . Displace. Therefore, the rotation of the drive shaft 7 corresponding to the displacement amount e is obtained. By adjusting the amount of displacement, the rotational position of the drive shaft 7 with respect to the pulley 9 (the phase with respect to the plate cylinder on the upstream side) can be arbitrarily shifted. FIG.
In the case of (a), the engaging pin 17 is guided to the upper left in the figure by the oblong slot 15, so that the drive shaft 7 rotates leftward when viewed from the L side. FIG. 8B shows the phase adjustment when the adjustment member 40 is moved to the right. In this case, the drive shaft 7 rotates rightward when viewed from the L side.

In each of the above embodiments, the case where the number of printing drums (plate cylinders) is two has been described.
From this point onward, all of the plate cylinders on the downstream side are provided with the phase adjusting mechanism of the present invention individually. Further, the adjusting means 12 in each of the above embodiments is not limited to the feed screw type, and can change the engagement position between the oblong hole and the engagement pin, and prevents the synchronized rotation of the drive shaft or the like after the adjustment. Any configuration may be used, and various configurations can be adopted. In addition, the positional relationship between the oblong slot 14 and the engaging pin 16 and the positional relationship between the oblong slot 15 and the engaging pin 17 may be reversed between the drive shaft and the pulley.

[0030]

As described above, according to the present invention,
Without using a timing belt for phase adjustment, the rotational position of the drive shaft of the plate cylinder on the downstream side in the transport direction of the printing paper relative to the pulley can be adjusted arbitrarily, so that the timing belt for simultaneous driving of each plate cylinder can be adjusted. The length can be minimized, and a phase shift due to a long timing belt for simultaneous driving of each plate cylinder can be avoided. Therefore, the ghost phenomenon can be suppressed, and the quality of the printed matter can be improved. In addition, since the load on the drive shaft of each plate cylinder caused by the phase adjustment mechanism does not increase, it is not necessary to increase the drive source capacity of the phase adjustment mechanism, and power consumption can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a phase adjusting mechanism according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a main part of the phase adjustment mechanism shown in FIG.

FIG. 3 is a plan view of a rotation preventing structure of an adjustment member in the phase adjustment mechanism shown in FIG. 1;

FIGS. 4A and 4B are schematic side views showing a phase adjustment operation by the phase adjustment mechanism shown in FIG. 1, wherein FIG. 4A shows a case where the adjustment member is moved to the left, and FIG. 4B shows a case where the adjustment member is moved to the right. It is.

FIG. 5 is a schematic side view showing a configuration for wrapping a timing belt of the phase adjustment mechanism shown in FIG. 1;

FIG. 6 is a schematic front view of a multicolor stencil printing machine to which the phase adjustment mechanism shown in FIG. 1 is applied.

FIG. 7 is a schematic sectional view of a phase adjusting mechanism according to another embodiment.

8A and 8B are schematic plan views showing a phase adjusting operation by the phase adjusting mechanism shown in FIG. 7, wherein FIG. 8A shows a case where the adjusting member is moved to the left, and FIG. 8B shows a case where the adjusting member is moved to the right. It is.

FIG. 9 is a schematic side view showing a conventional phase adjustment mechanism.

[Explanation of symbols]

 6,7 Drive shaft 8,9 Pulley 10 Timing belt 12 Adjusting means 14,15 Inclined long hole 16,17 Engagement pin 18 Connecting pin 48 as connecting member 48 Rotation amount detecting means 60 Printing drum as upstream plate cylinder 62 Printing drum as downstream plate cylinder P Printing paper

Claims (5)

[Claims] A drive shaft and a pulley of the plate cylinder are provided in a non-fixed state with each other, and are formed on one of the drive shaft side and the pulley side with respect to the axial direction of the drive shaft. An oblong slot that is obliquely positioned, an engaging pin provided on the other side and engaged with the oblong slot, adjusting means for changing an engagement position between the oblong slot and the engaging pin, and the drive shaft side And a connecting member for connecting the pulley side to rotate synchronously. 2. A printing apparatus according to claim 1, wherein an upstream plate cylinder and a downstream plate cylinder in a printing paper conveyance direction are linked by a timing belt between pulleys provided on respective drive shafts. A phase adjustment mechanism that is used in a multi-cylinder printing apparatus that performs simultaneous printing by transferring each image to a printing sheet, and that adjusts a position shift of a printed image between plate cylinders in a printing sheet conveyance direction. The drive shaft and the pulley of the side plate cylinder are provided in a non-fixed state with each other, and are formed on one of the drive shaft side and the pulley side and positioned obliquely with respect to the axial direction of the drive shaft. An inclined elongate hole, an engaging pin provided on the other side and engaged with the oblique elongate hole, adjusting means for changing an engagement position between the oblique elongate hole and the engaging pin, the drive shaft side and the pulley side And a connecting member for connecting and synchronously rotating A phase adjustment mechanism in a printing device. 3. A phase adjusting mechanism according to claim 2, wherein said adjusting means has a feed screw structure. 4. The apparatus according to claim 3, wherein said adjusting means has a rotation amount detecting means for controlling the amount of adjustment.
A phase adjustment mechanism in the printing apparatus according to the above. 5. The phase adjusting mechanism according to claim 2, wherein said engaging pin also serves as said connecting member.