US3774533A

US3774533A - Rotary screen printing machine with internal squeegee

Info

Publication number: US3774533A
Application number: US00233038A
Authority: US
Inventors: S Ichinose
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-12-15
Filing date: 1972-03-09
Publication date: 1973-11-27
Anticipated expiration: 1990-11-27
Also published as: JPS4864287A

Abstract

A rotary screen printing machine wherein the rotary screen rises from the printing operation position at the time of termination of the printing operation and at this risen position the rotary screen is driven and rotated independently of the printing belt, whereby an undesired phenomenon that at the time of stoppage of the printing operation a printing paste or ink flows out through the screen onto the material to be printed or the printing belt and causes contamination of the material to be printed upon can be effectively prevented.

Description

United States Patent [1 1 Ichinose 1 Nov. 27, 11973 [54] ROTARY SCREEN PRINTING MACHINE 3,572,240 3/1971 Bohm lOl/116 WITH INTERNAL SQUEEGEE 3,420,167 1/1969 Van Der Winden 101/1 16 [76] Inventor: Shiro Ichinose, 11-8, l-chome, FOREIGN PATENTS OR APPLICATIONS Shinohara Kita-machi, 266,650 12/1966 U.S.S.R 101/1 16 Kobe, Japan 2 Filed; 9, 1972 Primary ExaminerRobert E. Pulfrey Assistant Examiner-Eugene H. Eickholt [21] Appl' 233038 Att0rneyE. F. Wenderoth et a1.

[30] Foreign Application Priority Data [57] ABSTCT 4 Dec 15? 1971 Japan 6/101042 A rotary screen printmg machine wherein the rotary [52] U S Cl 101 A19 101 89 screen rises from the printing operation position at the [51] a 13/00 time of termination of the printing operation and at [58] Fie'ld [114420 this risen position the rotary screen is driven and ro- 129 181 tated independently of the printing belt, whereby an 1 undesired phenomenon that at the time of stoppage of [56] References Cited the printing operation a printing paste or ink flows out through the screen onto the material to be printed or UNITED STATES PATENTS the printing belt and causes contamination of the ma- 3,291,044 12/1966 Van Der Winden 101/118 terial to be printed upon can be effectively preventecL 3,585,930 6/1971 Bohm 101/116 3,565,002 2/1971 Boehm 101/116 7 Claims, 6 Drawing Figures 15/ 33 22 [2 12% 2l 2O 1 p o) m o m o m m ,c; O

P'ATENIEDHnv 27 1975 SHEET 3n; 4

ROTARY SCREEN PRINTING MACHINE WITH INTERNAL SQUEEGEE This invention relatesto a rotary screen printing machine. More particularly, the invention relates to a rotary screen printing machine wherein the rotary screen rises from the printing operation position at the time of termination of the printing operation and at this raised position the rotary screen is driven and rotated independently of the printing belt, whereby the effluence of a printing paste or ink through'the screen can be effectively prevented at the time of stoppage of the printing operation.

A rotary screen printing machine of the type that has heretofore been used widely comprises pulleys provided on both sides of the printing operation zone, at least one of which is driven, a printing belt supported and driven by said pulleys, which is adapted for supporting a material to be printed and transporting it to the printing operation zone, a squeegee member mounted in the interior of the rotary screen for squeezing a printing paste or ink onto the material to be printed through said screen, anda drive mechanism for driving the rotary screen at a speed synchronized with the speed of the printing belt.

In the known rotary printing machine, when one printing cycle has been terminated, the color change, the design exchange and other operations are conducted after lowering of the printing belt from the printing operation position or raising of the rotary screen from the printing operation position, or without such lowering or rising of the printing belt or rotary screen. However, in the known rotary screen printing machine there is a great problem at the time of stoppage of the printing operation the printing paste or ink is flowing out onto the printing belt or the material to be printed which is supported on the printing belt and consequently causes contamination of the printing belt and the material to be printed no means capable of preventing effectively this efiluence of the printing ink from the screen has been found. Accordingly, in the conventional printing operation, a saucer for receiving the paste or ink is inserted below the rotary screen coincidentally with stoppage of the printing operation. However, such operation requires additional manual labor and is troublesome. Further, such operation is still insufficient for preventing completely contamination caused by the effluence of the printing ink.

l have now arrived empirically at the knowledge that in the rotary screen printing machine of the abovementioned type, the tendency of the printing ink or paste to flow out through the screen at the time of stoppage of the printing operation can be greatly inhibited by lifting up the rotary screen from the printing operation position at the time of stoppage of the printing operation and driving and rotating it at this raised position independently of the printing belt, with the consequence that contamination of the printing belt or the material to be printed which is supported on the belt caused by effluent paste orink can be effectively prevented.

whereby the effluence of the printing paste or ink through the screen can be effectively prevented at the time of stoppage of the printing operation.

My invention further seeks to provide a rotary screen printing machine whereinwhen the rotary screen is at the printing operation position, the force for driving the rotary screen is transmitted by a first drive mechanism for driving the printing belt and the rotary screen at a synchronized speed, and when the rotary screen is at the position in which it has been lifted up from the printing operation position, the force for driving the rotary screen is transmitted by a second drive mechanism independent of the first drive mechanism, in each case the transmission of the force for driving the rotary screen being effected through an idle gear mounted on a supporting shaft for supporting the rotary screen for vertical movement, whereby the rotary screen can be driven and rotated either during the printing rotary screen-at a speed synchronized with the speed of the printing belt, wherein a bearing device for the rotary screen is mounted on a supporting member, one end of which is pivoted on a supporting shaft and the other end of which is attached to a lifting device, a screen gear fitted on the rotary screen is driven by a screenternatively with a first drive mechanism for driving the Accordingly, it is a primary object of my invention to rotary screen at a speed synchronized with the speed of the printing belt and a second drive mechanism inde pendent of and first drive mechanism, whereby at the time of stoppage of the printing operation the rotary screen is caused to rise from the printing operation position and at this raised position the rotary screen is driven and rotated independently of the printing belt.

This invention will be explained more fully by reference to the accompanying drawings, which illustrate an embodiment of the rotary screen machine of this invention.. FIGS. LA and 1-8 are side views illustrating the drive mechanisms of the rotary machine of this invention, FIG. A-l showing the positions of the parts during the printing operation and FIG. l-B showing the positions of the parts at the time of stoppage of the printing operation.

FIGS. Z-A and 2-8 are side views illustrating the arrangement of the lifting device of the rotary screen printing machine illustrated in FIGS. l-A and ll-B, FIG. 2-A showing the positions of the parts during the printing operation and FIG. Z-B showing the positions of the parts atthe time of stoppage of the printing operation.

P16. 3 is an enlarged partial side view illustrating the supporting mechanism of the bearing device in the rotary screen printing machine of this invention.

FIG. 4 is a top plan view illustrating the supporting mechanism of the bearing device shown in FIG. 3.

ln FIGS. l-A and 1-8, on opposite ends of a frame 1, namely at the ends of the printing operation zone, a drive pulley 2 and an idle pulley 3 are mounted, and a printing endless belt 4 is stretched between drive and

idle pulleys

2 and 3, and supported and driven by these

pulleys

2 and 3. For driving the drive pulley 2, a drive shaft 3 on which the drive pulley 2 is fixed has a sprocket or pulley 6 mounted thereon, and the driving force supplied by a motor M is transmitted to the drive pulley 2 by means of a chain 9 (or drive belt 9) extending between a drive sprocket 8 (or pulley 8) of a reduction gear 7 mounted on the motor M and said sprocket 6 (or pulley 6).

Above the idle pulley 3, a material 10 to be printed, such as a cloth or fabric, is fed onto the upper surface of the printing belt 4, and supported and transported to the printing operation zone by the printing belt 4. The material 10' which has been printed is separated from the upper surface of the printing belt 4 above the drive pulley 2, following which the material 10' is forwarded to the drying or winding step. Above the idle pulley 3, a press roller 11 is provided so that it is in contact with the printing belt 4 travelling in the idle pulley 3, and the material 10 to be printed is fed between the press roller 11 and the printing belt 4 by a guide roller 12 mounted upstream of the press roller 11. Above the drive pulley 2 there is mounted a guide roller 13 to separate from the printing belt 4 the material 10' which has been printed and forward it to the subsequent treatment zone.

Above the printing operation zone, namely above the printing belt 4 stretched between the drive and

idle pulleys

2 and 3, one or a plurality of rotary screens 14 are disposed, in the interior of which a squeegee member 15 is provided for squeezing a printing ink or paste onto the material 10 to be printed through said screen. During the printing operation (FIG. l-A), the rotary screen 14 contacts with the material 10 to be printed, which is supported on the printing belt 4, and is driven at a speed synchronized with the travelling speed of the printing belt 4. Thus, an image of a pattern corresponding to that on the rotary screen 14 is printed and fonned on the material 10 to be printed. In the case of a plurality of rotary screens, their position and phase are so arranged that a desired pattern or combination of colors can be formed on the material 10 to be printed.

The prominent characteristic feature of this invention is that the bearing device for each rotary screen 14 is mounted on a supporting member, one end of which is pivoted on a supporting shaft and the other end of which is attached to a lifting device, the screen gear fitted on the rotary screen 14 is engaged with a screendriving gear through an idle gear fitted on the supporting shaft, and said screen-driving gear is connected alternatively with the first drive mechanism for driving the rotary screen 4 at a speed synchronized with the speed of the printing belt 4 and the second drive mechanism independent of the first drive mechanism.

In the printing machine of this invention, because of this characteristic construction it is possible to drive the rotary screen 14 at the printing operation position at a speed synchronized with the speed of the printing belt 4 during the printing operation and to drive and rotate the rotary screen 14 at the position lifted from the printing operation position independently of the printing belt 4 at the time of stoppage of the printing operation, whereby effluence of a printing paste or ink through the screen can be effectively prevented.

The above characteristic feature will now be described in detail with reference to FIGS. 2-A and 2-B and FIG. 3. As can be seen from FIG. 3, a bearing device 16 for each rotary screen 14 is mounted in a supporting member 21 pivoted at one end 17 on a supporting shaft 18, and the other end 19 is attached to a lifting device 20. The supporting shaft 18 is supported rotatably on the frame 1. Thus, the supporting member 21 can oscillate around the supporting shaft 18 as the center, and with oscillation of the supporting member 21, also the rotary screen 14 can oscillate around the supporting shaft 18 as the center. The lifting devices 20 are mounted on a lift frame 22, and an optional mechanism for vertically moving the lift frame 22 is mounted on the frame 1. As can be seen from FIGS. 2-A and 2-B, racks 23 are provided on the lift frame 22 extending in the vertical direction, and pinions 24 are mounted rotatably at positions engaged with the racks 23. One end of an oscillating arm 25 is fixed to each pinion 24, and the other end of the oscillating arm 25 is oscillatably mounted on a silde shaft 26. One end of the slide shaft 26 is attached to an am 28, one end of which is oscillatably fitted on a shaft 27. The other end of the arm 28 is connected with a piston member 30 of a pressure cylinder 29. When the slide shaft 26 is shifted in the right direction by introducing into the piston member 30 a pressurizing fluid such as compressed air or oil, the pinion 24 is rotated is the counter-clockwise direction and the racks 23 are shifted upwardly, whereby the lift frame, the lifting member and the rotary screens 14 are lifted, in turn, from the printing operation position shown in FIG. 2-A to the upper position shown in FIG. 2-B. The lifting and lowering of the lift frame 22 may be accomplished by employing a known hydraulic machine instead of the lifting and lowering mechanism shown in FIGS. 2-A and 2-B.

In this invention, it is preferred that, as is illustrated in FIG. 2, the squeegee members 15 be supported by the lift frame 22. If such method of supporting the squeegee members 15 is adopted, the squeegee members 15 are shifted by a distance corresponding to the lifting distance (/1 of the lift frame 22, while the screens are lifted only a distance expressed by the following equation:

wherein h stands for the distance the lift frame 22 is raised, k indicates the distance the screen 14 is raised, d designates the distance between the supporting shaft 18 and the lifting device 20, and 11, represents the distance from the supporting shaft 18 to the point at which each screen 14 comes into contact with the corresponding squeegee member 15. Accordingly, with the rise of the lift frame 22, between the inner surface of each screen 14 and the end point of the squeegee member 15 there is formed a space expressed by the following formula:

Therefore, at the risen position the rotary screens 14 can be driven and rotated without coming into contact with the squeegee member 15, with the result that the problem of bleeding of the printing paste or ink can be solved more effectively.

As is illustrated in FIGS. 1-A and l-B, a screen gear 31 is attached to the end portion of each rotary screen 14, and the gear 31 is engaged with an idle gear 32 fitted on the corresponding supporting shaft 18. As is illustrated in FIGS. 3 and 4, a shaft 33A is mounted on each lifting member 20, and on both ends of the shaft 33A there are mounted gears 33 so that the gears 33 are engaged with screen gears 31 mounted on both ends of the rotary screen 14. With such a construction, by means of the idle gear 32, the drive force transmitted to one end of the screen 14 is conveyed to the other end of the screen 14 through the screen gear 31 on one end, the gear 33 on one end, the shaft 33A, the gear 33 on the other end and the screen gear 31 on the other end. By adopting such a construction, an undesired phenomenon of twisting of the screen can be prevented effectively. Below the idle gear 32 fitted on each supporting shaft 18, a screen-driving gear 34 is provided so that it is engaged with said idle gear 32. A helical worm gear 35 is fixed to each screen-driving gear 34, and is meshed with a helical gear 37 attached to a screendriving shaft 36 extending in the longitudinal direction of the frame 1. By rotation of the screen-driving shaft 36, the screen-driving gears 34 are driven through the engagement between the helical gears 37 and the helical worm gears 35, and the drive force of the screendriving gears 34 is conveyed to the screen gears 31 through the idle gears 32, whereby the rotary screens 14 can be driven and rotated smoothly irrespective. of the position of the screens 14.

One end of the screen-driving shaft 36 is connected via a magnetic clutch or other known clutch M1 to a first drive mechanism, and the other end of the shaft 36 is connected via a magnetic clutch or other known clutch M2 to a second drive mechanism. Any mechanism capable of driving the rotary screens 14 at a speed synchronized with the speed of the printing belt 4 may be used as the first drive mechanism. For instance, the drive mechanism M for the drive pulley 2 driving the printing belt 4 may be utilized also as the first drive mechanism. However, in this invention it is preferred that the idle pulley 3 of the printing belt 4 be used as the first drive mechanism for driving and rotating the rotary screens 14 at a speed synchronized with the speed of the printing belt 4.

For attainment of the above, in FIG. 1-A, a spur drive gear 39 is fixed on the shaft 38 on which the idle pulley 3 is fixed, an idle gear 40 is mounted so that it is engaged with the drive spur gear 39, and an exchangeable change gear 41 is mounted so that it is engaged with the idle gear 40. A bevel gear (not shown) is fixedto the change gear 41. From this bevel gear the drive force is transmitted through a bevel gear 42, another bevel gear 43 connected to the bevel gear 42, and still another bevel gear 44 to a drive shaft 45, one end of which is fixed to the bevel gear 44. To the other end of the drive shaft 45 is fixed a spur gear 46 which is engaged with a spur gear 47 mounted freely movably on the screen-driving shaft 36. The spur gear 47 fitted on the shaft 36 and the magnetic or other known clutch M1 attached to the shaft 36 are so arranged that when the clutch M1 is actuated, the shaft 36 is driven and rotated by the drive force conveyed to the spur gear 47 and when the clutch M1 'is not actuated, the spur gear 47 and the screen-driving shaft 36 are rotated independently of each other. Thus, when the clutch M1 is actu-.

ated, with the movement of the printing belt 4 the idle pulley 3 is rotated at a surface speed synchronized with the speed of the printing belt 4 and the rotation force of the idle pulley 3 is transmitted to the drive shaft 45 through the

gearing mechanism'comprising members

39, 40, 41, 42, 43 and 44. Then, by the engagement be belt 4. When the drive means such as illustrated in FIGS. 1-A and 1-B is used, even when slippage occurs between the drive pulley 2 and the printing belt 4, it is possible to drive and rotate the rotary screens 14 at a speed synchronized completely with the speed of the printing belt 4, because the load imposed between the idle pulley 3 and the printing belt 4 is smaller than the load imposed between the drive pulley 2 and the printing belt 4 and hence, the frequency of occurrence of slippage between the idle pulley 3 and the printing belt 4 is much lower than the frequency of occurrence of slippage between the drive pulley 2 and the printing belt 4. Further, the rotation of the rotary screens 14 by the idle pulley 3 is not influenced by unevenness of the elongation of the printing belt 4. The change of the diameter of the rotary screens 14, i.e., the change of the design size, may be accomplished easily by exchanging the change gear 41. It is preferred that the idle pulley 40 be mounted oscillatably around the shaft 38 in engagement with the drive spur gear 39, so that a change gear 41 suitable for attaining a screen synchronized with the speed of the printing belt can be readily attached.

In FIGS. 1-A and 1-B, to the other end of the screendriving shaft 36 is connected a motor 45 equipped with a reduction gear for driving and rotating the rotary screen independently through the magnetic or other known clutch M2. When the above-explained first clutch M1 is not actuated and the second clutch M2 is actuated, the screen-driving shaft 36 is driven and rotated by the motor 48 equipped with a reduction gear, and the rotary screens 14 are then driven and rotated by means of the gearing

mechanism comprising members

37, 35, 34, 32 and 31.

The printing operation with use of the printing machine of this invention is conducted in the following manner. In FIGS. l-A and 1-B, the first clutch M1 is actuated and the second clutch M2 is not actuated. By operation of the drive motor M, the drive pulley 2 is driven and rotated, and with the rotation of the pulley 2, the endless belt 4 for printing is driven. The material 10 to be printed passes over guide rollers 12 and is fed between a pressure roller 11 and the printing belt 4 travelling on an idle pulley 3. The material 10 is fed onto the upper surface of the printing belt 4 and continuously forwarded to the printing operation zone. With the rotation of the idle pulley 3, the drive shaft 45 is driven and rotated, which results in rotation of the rotary screens 14 at a speed synchronized with the speed of the printing belt 4. At this time, the lift frame 22 is in the lowermost position as illustrated in FIG. 2-A and the rotary screens 14 contact the material 10 on the printing belt 4. The squeegee member 15 contacts the inner surface of each rotary screen 14 and it causes a printing ink or paste fed into the interior of the rotary screen 14 to ooze out through the screen onto the material 10 to be printed which is on the printing belt 4. Thus, the printing of the material 10 is accomplished. The material 10 which has been printed is separated from the printing belt 4 on the discharge side of the printing belt 4, and is forwarded through a guide roller 13 to the subsequent treatment zone, for instance, the drying or winding zone. After passage through the drive pulley 2, the endless belt 4 for printing is subjected to such treatments as surface washing and drying and comes to the position of the idle pulley 3, following which the above operation procedures are repeated.

Initiation of the printing operation may be effected while maintaining the rotary screens 14 at the position illustrated in FIGS. l-A and 2-A. In order to prevent wear of the rotary screens 14 at the time of initiation of the printing operation, however, it is preferred to initiate the operation by maintaining the rotary screens 14 at the position illustrated in FIGS. 1-8 and 2-B and lowering the rotary screens 14 coincidentally with initiation of driving of the printing belt 4.

At the time of stoppage of the printing operation, a fluid is introduced into the fluid cylinder 29, and the racks 23 and, in turn, the lift frame 22 are lifted as illustrated in FIG. 2-B. With the lifting of the frame 22, the rotary screens 14 are rotated upwardly around the supporting shaft 18 and separate from the material to be printed which is on the printing belt 4. Also with the lifting of the lift frame 22, the end of each of the squeegees parts from the inner surface of the screen 14. Coincidentally with rising of the lift frame 22, the operation of the drive motor M for driving the printing belt 4 is stopped, and disengagement of the first clutch M1 and engagement of the second clutch M2 are simultaneously effected. As a result, the screen-driving shaft 36 is driven and rotated by the motor 48 through the reduction gear, and the rotary screens 14 are driven and rotated independently of the printing belt 4 by means of the gearing

mechanism comprising members

37, 35, 34 32 and 31.

According to this invention, as described hereinabove, at the time of termination of the printing operation, the rotary screen 14 is lifted from the printing operation position (shown in FIGS. l-A and 2-A) to the raised position shown in FIGS. 1-8 and 2-B, and at this risen position the rotary screen 14 can be driven and rotated independently of the printing belt 4, whereby an undesired phenomenon that at the time of stoppage of the printing operation the printing paste or ink flows out through the screen onto the material to the printed or the printing belt can be effectively prevented.

I claim:

1. A rotary screen printing machine comprising pulleys at opposite ends of a printing operation zone, at least one pulley being a driven pulley, a printing belt supported on and driven by said pulleys for supporting a material to be printed and transporting it through the printing operation zone, at least one rotary screen positioned above said belt in said printing operation zone, a squeegee member in the interior of said rotary screen for squeezing a printing paste or ink through the rotary screen onto the material to be printed, a first drive mechanism for driving the rotary screen at a speed synchronized with the speed of the printing belt, a bearing device on which the rotary screen is rotatably mounted, a supporting member on which said bearing device is mounted a supporting shaft on which one end of said supporting member is pivotally mounted, a lifting device to which the other end of said supporting member is attached, a screen gear on the rotary screen, an idle gear on said supporting shaft engaged with said screen gear, a screen driving gear engaged with said idle gear,

a second drive mechanism independent of said first drive mechanism, and means alternatively connecting said screen driving gear with said first drive mechanism and said second drive mechanism, whereby when the printing operation is stopped, the rotary screen can be raised from the printing operation position by said lifting device and in the raised position the rotary screen can be driven and rotated independently of the printing belt.

2. A rotary screen printing machine as claimed in claim 1 wherein said lastmentioned means comprises a screen driving shaft, a gearing mechanism coupled between said screen driving shaft and said screen driving gear, and means at the ends of said screen driving shaft for coupling said screen driving shaft to said first and second drive means, respectively.

3. A rotary screen printing mechanism as claimed in claim 2 wherein the means for connecting the screen driving shaft to said first drive mechanism is a first clutch mechanism at one end of said screen driving shaft, and said means for connecting the screen driving shaft to the second drive mechanism is a second clutch mechanism, said first drive mechanism comprising a gearing mechanism coupled to one of said pulleys for and belt for transmitting the rotation of said pulley, and a drive shaft coupled between said gearing mechanism and said first clutch mechanism for transmitting the rotation of said drive shaft through the first clutch mechanism to said screen driving shaft.

4. A rotary screen printing machine as claimed in claim 1 in which said screen gear is on one end of said rotary screen, and said machine further comprises a further screen gear on the other end of said rotary screen, a shaft rotatably mounted on said lifting device, and first spur gear fixed on one end of said shaft and engaged with said firstmentioned screen gear, and a second spur gear on the other end of said shaft engaged with said further screen gear.

5. A rotary screen printing machine as claimed in claim 1, in which said lifting device comprises a vertical member on which said supporting member is mounted, a vertically movable lift frame on which said vertical member is mounted, and a fluid pressure actuated means coupled to said lift frame for raising and lowering said lift frame.

6. A rotary screen printing machine as claimed in claim 5 in which said squeegee member is mounted on said lift frame and positioned within said rotary screen so that when the rotary screen is in contact with the material to be printed the blade of said squeegee member is in contact with the inner surface of the rotary screen, and when the rotary screen is in the raised position, the blade of the squeegee member is spaced from the inner surface of the rotary screen.

7. A- rotary screen printing machine as claimed in claim 1 in which there are a plurality of rotary screens each having an associated squeegee member, bearing device, supporting member, lifting device screen gear,

idle gear and screen driving gear.

Claims

1. A rotary screen printing machine comprising pulleys at opposite ends of a printing operation zone, at least one pulley being a driven pulley, a printing belt supported on and driven by said pulleys for supporting a material to be printed and transporting it through the printing operation zone, at least one rotary screen positioned above said belt in said printing operation zone, a squeegee member in the interior of said rotary screen for squeezing a printing paste or ink through the rotary screen onto the material to be printed, a first drive mechanism for driving the rotary screen at a speed synchronized with the speed of the printing belt, a bearing device on which the rotary screen is rotatably mounted, a supporting member on which said bearing device is mounted a supporting shaft on which one end of said supporting member is pivotally mounted, a lifting device to which the other end of said supporting member is attached, a screen gear on the rotary screen, an idle gear on said supporting shaft engaged with said screen gear, a screen driving gear engaged with said idle gear, a second drive mechanism independent of said first drive mechanism, and means alternatively connecting said screen driving gear with said first drive mechanism and said second drive mechanism, whereby when the printing operation is stopped, the rotary screen can be raised from the printing operation position by said lifting device and in the raised position the rotary screen can be driven and rotated independently of the printing belt.

7. A rotary screen printing machine as claimed in claim 1 in which there are a plurality of rotary screens each having an associated squeegee member, bearing device, supporting member, lifting device screen gear, idle gear and screen driving gear.