US3413732A

US3413732A - Drying device for freshly printed sheets

Info

Publication number: US3413732A
Application number: US637443A
Authority: US
Inventors: Koch Werner; Preuss Friedrich
Original assignee: Roland Offsetmaschinenfabrik Faber and Schleicher AG
Current assignee: Roland Offsetmaschinenfabrik Faber and Schleicher AG
Priority date: 1966-05-21
Filing date: 1967-05-10
Publication date: 1968-12-03
Anticipated expiration: 1985-12-03
Also published as: DE1260482B; GB1150678A

Description

Dec. 3, 1968 w, KOCH ETAL 3,413,732

DRYING DEVICE FOR FRESHLY PRINTED SHEETS Filed May 10, 1967 4 Sheets-Sheet 1 Fig. I

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DRYING DEVICE FOR FRESHLY PRINTED SHEETS Filed May 10, 1967 4 Sheets-Sheet 2 Fig. 2

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DRYING DEVICE FOR FRESHLY PRINTED SHEETS Filed May 10, 1967 4 Sheets-Sheet 3 Inventors \itmmv. \Qeu YmtMtmu R: use

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Dec. 3, 1968 w. KOCH ETAL DRYING DEVICE FOR FRESHLY PRINTED SHEETS 4 Sheets-Sheet 4 Filed May 10, 1967 5 M 5 n QMY Q s a. V u 4 F a x YM \W w A m mm b a I m w w nkl 3,413,732 DRYING DEVICE FOR FRESHLY PRINTED SHEETS Werner Koch, Gotzenhain, and Friedrich Preuss, Neu- Isenburg, Germany, assignors to Roland Olfsetmaschinenfabrik Faber & Schleicher A.G., Offenbach am Main, Germany, a firm of Germany Filed May 10, 1967, Ser. No. 637,443 Claims priority, application Germany, May 21, 1966, R 43,315- 7 Claims. (Cl. 34-162) ABSTRACT OF THE DISCLOSURE A device for drying printers ink on freshly printed sheets printed in a printing press and before being transported, one by one, to a treatment station. The device includes substantially vertically disposed up and down drying paths along which the sheets to be dried are guided by endless conveyors. The device also includes means for restoring moisture lost by the sheets while being dried, for instance, by hot air. Such vertical disposition of the drying paths reduces the space required for the device so that the same can be conveniently installed between the printing assembly of the press and the treatment station.

The invention relates to a device for drying the printers ink on sheets freshly printed in the printing assembly of a printing press, and more particularly, to a drying device in which the freshly printed sheets are gripped at the leading edges by suitable grippers and are transported by endless conveyors along a straight path to a further treatment station.

With drying devices of this kind it is obviously important that the freshly printed surface is not smeared when and while the sheets are transported to the further treatment station such as a station in which additional operations are performed on the sheets. It is also essential that bending or other dislocation of the sheets is avoided. Moreover, it is desirable that the sheets are dried as quickly as possible so that there is little or no waiting time before further operations on the sheets can be effected, for instance, by a sheet folding machine.

It has been proposed to powder the freshly printed sheets with lime dust or similar powders. However, a machine in which powdered sheets are processed is bound to become dirty and the sheets themselves also tend to become smudged by the powder.

As is evident, rapid drying of freshly printed sheets has several advantages. It also tends to enhance the brilliance and clarity of the print. I

However, no nearly satisfactory sheet drying device is available as yet. It is known to interpose between the printing unit of a letter press perfecting rotary printing press a drying device through which the freshly printed sheets are moved along a horizontal path by an endless conveyor. Such drying devices are full disclosed, for instance, in Patent 2,174,865. Drying devices of this kind have the disadvantage that they very much increase the total length of the printing installation. In particular, with high speed printing presses the drying paths required for adequate drying of the sheets must be so long due to the high speed with which sheets are delivered to the paths that the device becomes impractical for reasons of space.

It is a broad object of the present invention to provide a novel and improved sheet drying device in which drying paths of adequate length even for use in conjunction with high speed presses can be accommodated in a comparatively small space.

It is also an object of the invention to provide a novel ted States Patent 3,413,732 Patented Dec. 3, 1968 and improved drying device in which each sheet is gripped so that it is guided along the drying paths of the device in fixed positions in reference to preceding and subsequent sheets and in reference to the paths thus avoiding smearing of the sheets by contact with each other while they are still wet and assuring uniform drying of the sheets.

A further object of the invention is to provide a novel and improved drying device which is associated with means for restoring moisture lost by the sheet material during the drying operation so that the normal pliability and strength of the sheet material are preserved.

The afore-pointed out objects, features and advantages and other objects, features and advantages of the invention will be pointed out hereinafter, are attained by providing drying conveyor means which guide the sheets to be dried up and down along substantially vertically disposed drying paths and by further providing gripper means gripping the leading edge and the trailing edge of each sheet as the same arrives at the drying device. Such gripping of the sheets at both edges prevents fluttering of the rear parts of the sheets as they pass through the drying device and thus smearing of the sheets and localized warming thereof. As is evident, vertical up and down drying paths require much less space than would be required by a straight drying path of the same total length but horizontally disposed.

Another aspect of the invention is to provide a heating means adjacent to the run of the conveyor means leading the sheets upwardly and a cooling means adjacent the run of the conveyor means leading the sheets downwardly in the drying device. Stationary guide bars supporting the sheets on the dry side thereof while the sheets pass through the drying device may be provided. The guide bars are preferably so mounted that the heat losses caused by the bars are reduced to a minimum.

The rotary components of the conveying means of the device are preferably mounted on the side of the guide bars distant from the heating means and the cooling means so that the rotary components are well protected against large temperature gradients.

The invention also contemplates to provide a dampening device posterior of the drying device. Such dampening device serves to restore the normal moisture contents of the sheets which tend to be reduced to a certain extent by heating of the sheets during the drying operation. The dampening means may be located closely adjacent to the cooling means of the drying device.

Further cooling of the sheets may be efiected by one or several cooled drums also disposed posterior of the drying device. Such cooled drums effect a final glazing or smoothing of the sheets.

The conveyor means of the drying device preferably comprise two endless chain conveyors one carrying the grippers for the leading edge of the sheets and the other carrying the grippers for the trailing edge of the sheets. The respective drive gears for the two conveyors are preferably angularly adjustable in reference to each other so that the drying device can be set for different sizes of sheets to be dried.

In the accompanying drawing a preferred embodiment of the invention is shown by way of illustration and not by way of limitation.

In the drawing:

FIG. 1 is a diagrammatic elevational side view of a sheet drying device according to the invention in conjunction with a printing device and a sheet laying-out station;

FIG. 2 is a diagrammatic elevational front view of the drying device according to FIG. 1 as seen from the left side thereof;

FIG. 3 is a plan view of the drying device, partly in section;

FIG. 4 is a fragmentary sectional view of the upper part of FIG. 2 on an enlarged scale; and

FIG. 5 is a fragmentary sectional view of the lower part of FIG. 2 on an enlarged scale.

Referring now to the figures more in detail, the exemplified installation comprises a diagrammatically shown printing device 1 in which the sheets to be dried are printed. The printing device should be visualized as being conventional and does not constitute part of the invention.

The freshly printed sheets are transported, one by one, by an also conventional conveyor 2 such as a chain conveyor to a drying device 3. The direction of travel of con veyor 2 is indicated by an arrow.

The drying device comprises two conveyor means 9 and 10 such as chain conveyors (FIG. 3). Conveyor means 9 supports gripper shafts 11 which mount grippers 12 and conveyor means 10 mounts gripper shafts 13 which mount grippers 14. Grippers 12 serve to grip the leading edge of a sheet to the dried and grippers 14 the trailing edge of the sheet. The gripping and release action of the grippers is not shown in detail. It should be visualized as conventional. The structure of the grippers as such, does not constitute part of the invention. The spacing of the

grippers

12 and 14 can be adjusted in accordance with the lengthwise dimensions of a sheet (FIG. 2) as will be more fully explained hereinafter.

Gripper shaft 11 is mounted on outer chains 23 and 24 (conveyor means 9) which are guided over sprocket gears 15, 16 and 17, 18 respectively and are further guided by chain guides 19 and 20. Similarly, gripper shaft 13 is mounted on inner chains and 36 which are guided over sprocket gears 27, 28 and 29, 30 respectively and are further guided over chain guides 31 and 32. The correponing sprocket gears of both chain conveyors 9 and 10 are mounted on the

same shafts

69 and 70 so that they can be angularly rotated in reference to each other as is shown in FIGS. 4 and 5.

A sheet is gripped at its leading edge and its trailing edge by

grippers

12 and 14 when it reaches the device 3 on conveyor 2 and is upwardly guided along a vertical path. While travelling upwardly, it passes a heating device 39 which may, for instance, direct a hot air flow upon the passing sheet. Air may be supplied by a pipe 39a.

Stationarily mounted guide bars 40 additionally support the sheets during its entire upward and downward travel through the drying device. The guide bars engage the nonprinted side of the sheets or in any event, the dry side thereof. They are secured at one end to

U-shaped brackets

41 and 42 respectively. The other end of the guide bars is so held that the bars can lengthwise expand without being deformed. Moreover, the guide bars are steadied at the upper turn-around of transport conveyors 9 and 10 by rotary discs 43.

The sheets after having reached the upper end of the conveyor path are guided downwardly past a cooling de vice 45 in which they are exposed, for instance, to a flow of cool air.

After leaving the cooling device the sheets are guided over water cooled

drums

46, 47 and 48 and finally reach a transport conveyor 38 which delivers the now dried and cooled sheets to a laying-out table 49.

While the sheets move over the cooling

drums dampeners

50 and 51 direct a spray of water upon the side of the sheets opposite to the freshly printed but now dried one. The purpose of moistening the sheets after having passed through heating device 39 is to replace the water contents of the sheets lost in the heating device. The moisture contents of the cool air used in cooling device 45 may be enriched by a water spray nozzle 52 (see FIG. 3) included in a pipe 53 through which air is supplied to the cooling device.

A drive means 4 for driving the conveyor means of the device 3, the cooling drums 46, 47 and 48 and the transport conveyor 38 is coupled to conveyor 2 via

gears

55, 56, 57, 58 and 59 housed in a gear box 54.

The drying device is closed off by

side walls

60 and 61 which are secured, for instance, by screws at 62 (see FIG. 3) respectively to an overhanging part of the frame structure 63 of printing device 1 and to an overhanging part of the frame structure 64 of the sheet laying-out table 49. Further side walls 65 and 66 of U-shaped cross-section are secured to

side walls

60 and 61 bridging the same.

A heat insulated intermediate wall 68 separates the up and the down paths of the conveyors, that is, the hot part and the cold part of the drying device.

As is shown more in detail in FIGS. 4 and 5, sprocket gears 15 to 18 for chain conveyor means 9 are secured on

shafts

69 and 70 by pins 71 or other suitable fastening means. Moreover, a sleeve 75 is secured on shaft 69 by pins 74. The sleeve 75 is further secured to gear 15 by one or several screws 73. Gears 27 to 30 of second chain conveyor means 10 are seated on

shafts

69 and 70 respectively angularly rotatable in reference thereto.

Gears

28 and 27 are fixedly secured to each other by a spacer sleeve 76 and screw bolts 77 and 78. Screw 77 also serves to secure a spring assembly 79 to gear 27. Similarly, gears 29 and 30 are secured to each other by means of a spacer sleeve 95 (see FIG. 4).

Gears

27 and 28 and thus, also gears 29 and 30 are restrained against rotation in reference to

shafts

69 and 70 by pressing a bushing 81 against spring assembly 79. This bushing is lengthwise slidable on sleeve 75 but secured against rotation by keys 80. Displacement of bushing 81 toward the left as seen in FIG. 5 is effected by means of bolts 82 which, in turn, are displaced by the pressure of a bearing sleeve 84. The bearing sleeve is slidable on a trunnion 83 of shaft 69 and also in a bore of wall 60. It is displaced by means of a spindle 85 having an external thread 86 engaging a threaded bore of trunnion 83 and a second external thread 87 engaging an internal thread of bearing sleeve 84. Thread 86 has a smaller diameter but a higher pitch than thread 87.

Discs 43 for steadying the guide bars 40 are supported on a spacer sleeve 95 supported by shaft 70' as is shown in FIG. 4. The discs include cut-outs 96 in which the gripper shafts may be accommodated as they move in unison with the chain conveyor means. Some of the discs are fixedly secured on the spacer sleeve while others are merely secured by lock rings 88 against axial displacement. Driving dogs 89 effect rotation of those discs that are held in fixed axial positions by rings 88.

The possibility of adjusting some of the discs by rotating the same on spacer sleeve 95 allows dimensioning of cut-outs 96 in accordance with the setting of the distances between gripper shafts 11 and 13 to adapt these distances to the dimensions of the sheets to be dried.

The chains of both chain conveyors 9 and 10 may be tensioned by a radial displacement of a bearing 90 for shaft 70 by turning a spindle 91 which is rotatable in side wall 60 but secured against lengthwise displacement in reference thereto.

While the invention has been described in detail with respect to a certain now preferred exampled and embodiment of the invention, it will be understood by those skilled in the art, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed is:

1. A device for drying printers ink on freshly printed sheets, said device comprising in combination:

endless drying conveyor means having a substantially vertically disposed up and down path of travel for drying sheets placed upon the conveyor means for travelling with the same;

a plurality of first gripper means and second gripper means for gripping the leading edge and the trailing edge respectively of a sheet fed upon said conveyor means, said gripper means being secured to the conveyor means for travel in unison with the same;

endless transport conveyor means for feeding freshly printed sheets with the freshly printed side thereof facing upward, one by one, to said drying conveyor means at the beginning of the upward path thereof;

second transport conveyor means for transporting sheets arriving at the lower end of the downward path of the drying conveyor means to a treatment station; and

dampening means adjacent to said second transport conveyor means for applying moisture to the side of the sheets opposite to the freshly printed side thereof while the sheets are travelling on said transport conveyor means.

2. The device according to claim 1 and comprising heating means disposed adjacent to the upward path of the drying conveyor means, and cooling means disposed adjacent to the downward path of the drying conveyor means for heat drying and cooling respectively sheets moving along said paths.

3. The device according to claim 1, wherein said second transport conveyor means include second cooling means.

4. The device according to claim 3, wherein said second cooling means comprise fluid cooled rotary drums.

5. The device according to claim 1, wherein said drying conveyor means comprise a first conveyor mounting the first gripper means and a second conveyor mounting the second gripper means, a pair of shafts, one of said shafts being mounted at the upper end and the other at the lower end of said up and down paths of the drying conveyor means, and upper and lower pulleys for each of said conveyors seated on said shafts for guiding and driving said conveyors.

6. The device according to claim 5 and comprising setting means for varying the angular positions of said pulleys in reference to each other thereby correspondingly varying the relative positions of the first and second gripper means to adapt the gripper means positions to different sizes of the sheets.

7. The device according to claim 5, wherein said first and second conveyors are chain conveyors and said pulleys are sprocket gears.

References Cited UNITED STATES PATENTS 1,613,445 1/1927 Davis et al. 34162 XR 2,174,864 10/1939 Barber 1014l6 XR 2.376,866 5/1945 Butler 34162 XR FREDERICK L. MATTESON, ]R., Primary Examiner.

A. D. HERRMANN, Assistant Examiner.