Patent Application
20200001596
The present invention relates to cleaning the ink reservoir in a printing press.
With the increasing frequency of printing on recycled papers, there becomes apparent a problem that printing presses are contaminated by paper dust. The paper dust moves from a blanket cylinder and so on to the ink fountain with ink and clogs the clearance between the ink fountain and the ink fountain roller. Therefore, the ink flow through the ink fountain roller towards the ductor roller is decreased, and printing density decreases. As a result, workmen have to clean the ink fountain to remove paper dust. This is an additional job to the workmen and makes the printing halted during the cleaning.
Related pieces of the prior art are described. According to Patent Document 1 (JP3194174B), the surface of the ink fountain is covered with a sheet freely windable and feedable. The sheet is wound up and fed to cover the ink fountain with a new face of the sheet when changing the ink. Further, the ink on the ink fountain roller is scraped by a blade.
According to Patent Document 2 (JP2866997B), the ductor roller is divided into plural individual rollers. The individual ductor rollers have adjustable individual contact periods to the ink fountain roller so that the printing density is adjustable for the individual ductor rollers. By the way, conventional ductor rollers advance and retract as a whole towards and from the ink fountain roller and are not divided into the individual rollers.
Patent Document 1: JP3194174B
Patent Document 2: JP2866997B
The Object of the Invention is
According to an inventive cleaning device for an ink reservoir for a printing press, the ink reservoir is formed between an ink fountain and an ink fountain roller and ink is supplied to a ductor roller advancing and retracting towards and from the ink fountain roller,
According to an inventive printing press, an ink reservoir is formed between an ink fountain and an ink fountain roller and ink is supplied to a plate cylinder via a ductor roller advancing and retracting towards and from the ink fountain roller,
According to an inventive cleaning method for an ink reservoir for a printing press, the ink reservoir is formed between an ink fountain and an ink fountain roller and ink is supplied to a plate cylinder via a ductor roller advancing and retracting towards and from the ink fountain roller,
According to the invention, the ink fountain is slid and retracted by the slide mechanism along the base to the cleaning position. At the cleaning position, the clearance between the tip end of the ink fountain and the ink fountain roller is enlarged from the normal position, and the clogged ink with dirt such as paper dust is discharged through the clearance. When the cleaning of the ink reservoir is completed, the ink fountain is advanced towards the ink fountain roller and is returned to the normal position; the clearance between the ink fountain and the ink fountain roller is returned to the normal value. Between the cylinder plate and the ink fountain roller, there are the ductor roller and ink distributing rollers; the printing is continued during the cleaning with the ink stored on these rollers. Then after the cleaning, the clearance between the ink fountain and the ink fountain roller is returned to the normal value.
The ink passed during the cleaning through the clearance between the ink fountain and the ink fountain roller is removed by a cleaner such as a doctor blade, a brush. Here, the cleaner is provided between the tip end of the ink fountain and the ductor roller along the rotational direction of the ink fountain roller. In synchronization with enlarging the clearance between the ink fountain and the ink fountain roller, the cleaner is made in contact with the ink fountain roller in order to remove the dirt in the ink and the ink.
In this specification, a movement towards the ink fountain roller is called an advancement, and a movement opposite to the ink fountain roller is called a retraction. More, the direction parallel to the tip end of the ink fountain (the direction parallel to the axis of the ink fountain roller) is called the left-right direction. Relative to the ink fountain, the end towards the ink fountain roller is called the tip end, the opposite end is the base end. Furthermore, in this specification, descriptions about the cleaning device are applicable to the printing press and the cleaning method, as they are.
Preferably, said slide mechanism is provided at left and right two portions of the rear end of the ink fountain and is configured to slide the left and right two portions of the rear end of the ink fountain by the same stroke. Thus, the tip end of the ink fountain is kept parallel to the axis of the ink fountain roller, and the clearance between the ink fountain and the ink fountain roller is kept constant along the tip end of the ink fountain.
Preferably, said slide mechanism comprises:
Since the quadric link makes the left-right pair of the arms rock by the same angle, the nuts in the feed screw mechanisms rock, and therefore, the screws advance and retract with a small stroke by the same length. While the drive member may be an air cylinder or the like, a servo motor as the drive member may precisely adjust the clearance between the ink fountain and the ink fountain roller according to the species of the ink, desired printing density, etc.
Preferably, said slide mechanism comprises at least a linear motor provided between the base and the ink fountain.
The linear motor makes the ink fountain slide without a gear and a screw, and therefore, no backlash is caused. Further, the linear motor may be provided between the base and the ink fountain, spaces at the rear end of the ink fountain is not occupied. Therefore, the slide mechanism does not need an additional space.
Preferably, the ink fountain is downwardly inclined where the tip end is down and the rear end is up, and, when the power supply to the linear motor is made off, then the ink fountain slides to the closed position by its own weight. Here, the force applied by the ink fountain to the ink fountain roller is less than the weight of the ink fountain, and an excessive force does not apply. While the linear motor uses the combination of an electromagnet, and a permanent magnet, antimagnetic body, or a magnetic body, etc., a piezoelectric linear motor having a piezoelectric body, etc. are usable.
Preferably, the linear motor is provided with an encoder, and the controller is configured to control the clearance at the normal position between the ink fountain and the ink fountain roller, assuming that, at the encoder value when the power supply is made on, the ink fountain is at the closed position. When a linear motor is used, the ink fountain slides naturally to the closed position, when the power supply is made off, and therefore, the encoder output when the power supply is made on represents one at the closed position. As a result, when controlling the normal position of the ink fountain, assuming that the encoder output when the power supply is made on corresponds to that at the origin (the closed position), the normal position of the ink fountain is simply and accurately controlled.
Preferably, a seal blocking the ink is provided between the ink fountain and the base so that dirt such as ink mist is prevented from entering between the ink fountain and the base. The seal is, for example, an elastic body such as rubber, and may be a self-lubricant sheet or a plate made of TEFLON (a registered trademark) or the like; the material of the seal is arbitrary.
Preferably, at least a guide member guiding the ink fountain along a sliding direction of the ink fountain in line contact with the ink fountain is provided between the base and bottom of the ink fountain. As a result, the ink fountain may smoothly be guided along the slide direction.
Preferably, a compensation means for increasing the quantity of the ink received by the ductor roller from the ink fountain roller before or after the slide of the ink fountain to the cleaning position is provided. When the ink fountain is retracted to the cleaning position and the cleaner is advanced, then the ink mixed with dirt is recovered. Then, the ink quantity received by the ductor roller may be decreased. Therefore, the compensation means increases the ink quantity received by the ductor roller from the ink fountain roller before the slide of the ink fountain to the cleaning position or after that. Then, the decrease in printing density according to the cleaning of the ink reservoir is reduced.
For example, said compensation means is configured to feed the ink to the ink reservoir before or after, preferably both before and after, the slide of the ink fountain to the cleaning position. When the ink quantity in the ink reservoir increases, then, the ink quantity passing through the clearance between the ink fountain roller and the ink fountain increases. For example, before the cleaning, the ink is fed in order to supply the ink which will be consumed by the cleaning in advance to the ductor roller, the ink distributing rollers, and so on. Or the ink is fed after the cleaning in order to supply the ink consumed by the cleaning to the ductor roller, the ink distributing rollers, and so on.
Preferably, said ductor roller is configured to be in contact with the ink fountain roller at a variable duty ratio, and
Preferably, said ductor roller comprises plural individual rollers arranged along an axial direction of the ink fountain roller and advancing and retracting separately to contact the ink fountain roller, and
Then, the cleaning effects evenly to the plural individual rollers, and the variations in printing densities along the axial direction of the ductor roller are prevented.
Preferably, said slide mechanism is configured to slide the ink fountain to three positions of the normal position, the cleaning position, and a closed position where the tip end of the ink fountain advances towards the ink fountain roller and prevents leakage of the ink through said clearance. Printing is performed at the normal position, the cleaning of the ink reservoir is performed at the cleaning position, and the leakage of the ink from the ink reservoir is prevented at the closed position. Therefore, if the ink is remaining in the ink reservoir during a halting period of the printing press, such as at night, the ink does not leak.
The best embodiment for carrying out the invention will be described in the following.
The tip end 5 of the ink fountain 4 is abutting and parallel to the ink fountain roller 10. The clearance between the tip end 5 and the roller 10 is changed in three ways: close contact where the clearance is nearly 0 (e.g. 10 μm or less); normal (e.g. about 0.05 mm-0.2 mm); and cleaning (eg. 0.2 mm-0.3 mm). At the rear end 6 of the ink fountain 4, there are provided a left-right pair of feed screw mechanisms 20. Double-headed screws 22 are made advanced and retracted by nuts 23, and thus, the ink fountain 4 is slid to the three positions. The ink fountain 4 is supported by a base 8 via guide members 42 and has a clearance 41 at other portions between the base 8 and the bottom of the ink fountain 4. In the specification, left and right indicate a direction parallel to the axis of the ink fountain roller 10 and the lengthwise direction of the rear end 6. Regarding advancement and retraction, a motion towards the ink fountain roller 10 is an advancement and a motion away it is a retraction.
There is the ink reservoir 18 between the ink fountain roller 10 and the ink fountain 4, and, through an ink supply portion 17, the ink is supplied from the ink reservoir 18 with the control by a controller 46. The ink fountain roller 10 draws the ink from the ink reservoir 18 as an ink film 70 and supplies to ink distributing rollers, not shown in the drawings, through the ductor roller 12. The ductor roller 12 is divided into plural individual rollers along its axis direction; the individual rollers advance and retract separately towards and from the ink fountain roller 10 in order to control separately the contact period with the ink fountain roller 10. However, conventional ductor rollers not divided into the individual rollers are usable. The ark-shaped arrow in
A doctor blade 14 (called “blade” below) under the ink reservoir 4 scrapes the ink film 70 from the ink fountain roller 10, and the scraped ink is stored in a pan 15. A cylinder 16 such as an air cylinder moves the blade 14 between a cleaning position for scraping the ink film 70 and a retracted position away from the ink fountain roller 10.
The ink fountain 4 is covered by a sheet not shown, supplied from an upper portion of the rear end 6 of the ink fountain 4, and wound between the base 8 and the pan 15. The sheet may not be provided and is not shown in the drawings in the embodiment. The clearance between the ink fountain 4 and the ink fountain roller 10 is indicated by the clearance excluding the sheet thickness.
Indicated by 46 is a controller for the entire unit, by 47 a controller for a servo motor 32, and by 48 a controller for the drive mechanism of the ductor roller 12. The controllers 46-48 may be provided separately or may be integrated into one controller. Further, the whole controllers 46-48 correspond to the controller in the claims.
The cleaning device 4 comprises: the ink fountain roller 10; the left-right pair of the feed screw mechanisms 20; a quadric link 40 shown in
The feed screw mechanisms 20 will be described. At the rear end 6 of the ink fountain 4, one of the heads of the double-headed screw 42 is screwed, the other head is engaged with the nut 23, and the nut 23 is supported by a fixing member 24. The fixing member 24 is fixed to the base 8 at a fixed portion 25, pinches the nut 23 with elements 24a, 24b, and has a thrust bearing 26 between the nut 23 and the element 24a at the side of the ink fountain 4. There is provided a biasing member 28 between the nut 23 and the element 24b opposite to the ink fountain 4; it presses elastically the nut 23 towards the thrust bearing 26 and is supported by an intermediate member 27. The bearing 26 is provided between the intermediate member 27 and the element 24 at the end. Thus, the nut 23 is biassed towards the thrust bearing 26 and is made to rock around its axis relative to the fixing member 24. There is provided a clearance 29 between the element 24a and the double-headed screw 22, and similarly is provided a clearance between the element 24b and the tip of the double-headed screw 22. Therefore, the double-headed screw 22 can advance and retract relative to the fixing member 24.
With reference to
Concerning the quadric link 40, the screw 36 advances and retracts by the rotation of shaft 35 of the servo motor 32 for operating the quadric link 40, and the left-right pair of the arms 30, 30 rock by the same angle. Further, the servo motor 32 is rockingly supported by the base 8; for example, the servo motor 32 is rockingly connected by a pin 37 fixed to the base 8.
The feed screw mechanisms 20 and the arms 30 are provided at least at the left and right two positions, but they may be provided at the three positions in the total of the center and left and right. The servo motor 32 is provided with an electromagnetic brake 32a, and the arms 30 are fixed when the power supply is made off, for example: when the printing press is made off at night; or when a momentary power failure is caused.
As shown in
With reference to
With reference to
When the servo motor 32 operates, then, the left and right arms 30 rock, and the left and right nuts 32 rock thereby. As a result, the left and right double headed screws 22 advance and retract, and the ink fountain 4 advances and retracts left and right equally. Further, the forth and back motion of the ink fountain 4 is supported by the guide members 42, and the biasing members 52 biasing the ink fountain 4 towards the ink fountain roller 10 prevent the backlash caused by the screws 22 and the nuts 23, or the like. Since the servo motor 32 adjusts accurately the clearance between the ink fountain 4 and ink fountain roller 10, the clearance is adjustable according to the species of the ink, aimed printing densities, and so on.
The ink fountain 4 is supported by the nuts 23 through the double-headed screws 22 and also supported by the guide members 42, and there is a clearance between the bottom face of the ink fountain 4 and the upper face of the base 8. Therefore, when the nuts 23 rock, the ink fountain 4 moves forth and back smoothly with the guide by the guide members 42. Further, the ink fountain 4 is pressed elastically towards the ink fountain roller 10 by the biasing members 52: the influence of the backlash is removed; and the ink will be prevented from leaking through the clearance between the ink fountain 4 and the ink fountain roller 10, if the ink fountain 4 will be advanced to a closed position, and if the power supply to the printing will be stopped then.
When the operation of the printing press is started (
According to the embodiment, the following advantageous effects are resultant:
Best Embodiment
As shown in
Instead of the left and right linear motors 82, 82, one linear motor 85 may be provided at the center portion along the left-right direction of the ink fountain 4 and the base 8. Further, instead of the linear guides 86, the guide members 42 in
Dirt such as ink mist are prevented from entering into the linear motors 82 and linear guides 86, preferably, by a seal 88 comprising a rubber packing, etc. enclosing the surrounding of the linear motors 82, 82 and the linear guides 86, 86. As shown enlarged in
In place of the rubber seal 88, a self-lubricant tape or a self-lubricant plate made of TEFLON (a registered trademark) or the like may be used. The self-lubricant seal endures against the repetitive sliding motion of the ink fountain 4 and blocks the ink mist, etc. since no gaps are generated between the ink fountain 4 and between the base 8.
The linear motors 82 lose the holding force when the power supply is cut. Therefore, the ink fountain 4 touches at the tip end 5 to the ink fountain roller 10 and the ink fountain 4 slides by its own weight to the closed position. Here, the force from the ink fountain 4 to the ink fountain roller 10 is less than the self-weight of the ink fountain 4.
Modification
Supplements
At the left side of the ductor roller 12 in
During the cleaning of the ink reservoir 18, ink is not transferred to the ductor roller, and therefore, the printing density may become lower. Counter-measures have been described in
Another versatile measure for preventing the printing density from lowering is to increase the duty ratio of the ductor roller touching the ink fountain roller before or after cleaning. The ductor roller operates at a predetermined period, and the duty ratio of the ductor roller touching ink fountain roller is adjusted for the adjustment of the printing density. If the duty ratio is increased both before and after cleaning, the buffered ink quantity is increased before cleaning and is restored after the cleaning. Of course, only before cleaning, or only after cleaning, the duty ratio of the ductor roller touching the ink fountain roller may be increased.
If the printing is slow and if the cleaning may be performed during the period T2, then, the cleaning does not affect the printing density. In this case, the processes in
1) in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-108878 | Jun 2017 | JP | national |
| 2017-136919 | Jul 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/042331 | 11/27/2017 | WO | 00 |
