US2802445A - Moistening means for duplicating machines - Google Patents

Description

Aug. 13, 1957 Filed July 26, 1954 L. A. SMITZER 2,802,445

MOISTENING MEANS FOR DUPLICATING MACHINES 3 Sheets-Sheet l 3, 1957 L. A. SMITZER 2,802,445

MOISTENING MEANS FOR DUPLICATING MACHINES Fild July 28, 1954 3 Sheets-Sheet 2 Aug. 13, 1957 A. SMITZER 2, 0

MOISTENING MEANS FOR DUPLICATING MACHINES Filed July 26, 1954 5 Sheets-Sheet s United States Patent D MOISTENING MEANS FOR DUPLICATING MACHINES Louis A. Smitzer, Chicago, Ill., assignor in Ditto, incorporated, Chicago, 111., a corporation of West Virginia Application July 26, 1954, Serial No. 445,850

6 Claims. (Cl. 1l87ii) This invention relates to improvements in moistening means for duplicating machines.

In duplicating machines of the type to which the present invention relates, the master sheet is carried on a rotating drum. A series of copy sheets are fed past the drum in pressure contact with the master sheet wh ch carries the characters which are to be duplicated. In order for the duplicating action to take place, the surface of each copy sheet must have been previously moistened.

In machines of this type, the copy sheets are forwarded to the drum, that is, to the bite of the drum and the pressure roll, by means of a pair of feed rolls. In order to secure proper registration, these feed rolls are intermittently driven. Moisture is applied to the copy sheet by the upper feed roll. Consequently, the feed rolls serve the triple function of feeding, positioning and moistening.

In order to perform the moistening function, it is desired to apply a thin film of liquid to the surface of the upper feed roll by suitable means. One such means comprises the combination of a spray means located above the upper feed roll and wiper means of fibrous material in contact with the feed roll which serves to distribute the fluid uniformly along the surface of the upper feed roll, this fluid often being referred to as a solvent. This arrangement has proved to be generally satisfactory for moistening a sheet which is of a width coextensive with the width of the feed rolls, since the amount of solvent supplied to the feed roll can be regulated by adjusting the stroke of the pump which controls the action of the spray means.

However, this arrangement is not entirely satisfactory if the copy sheet is substantially narrower than the roll for the reason that the film of moisture on those parts of the roll which are not contacted by the copy sheet is not absorbed by the copy sheet. This has several undesirable results.

In the first place, the fibrous material of the wiper tends to become saturated with the result that too much moisture is applied to that portion of the feed roll which is contacted by the copy sheet due to side capillarity in the wiper.

In the second place, the solvent tends to collect in a bead along the bite of the upper and lower feed rolls; this bead will extend itself laterally, particularly, when the feed rolls are stationary, with the result that the leading edge of the next copy sheet will become saturated wtih thi head of solvent.

In the third place, the solvent tends to build up on the lower feed roll with the result that the copy sheet will be moistened on the under-surface. This is particularly evident when changing from a narrow to a wide copy sheet. This film of moisture on the under-surface of the copy sheet will be transferred to the pressure roll, with the result that matter on the master sheet will become offset on the pressure roll, thus radically shortening the life of the master sheet. In the second instance where the leading edge is saturated, the master sheet may be 2,802,445 Patented Aug. 13, 1957 crashed which means that the characters of the master sheet are obliterated by blotting and running.

The foregoing undesirable features will occur irrespective of whether the duplicating action is of the solvent type, or of the reaction type, the former referred to a dissolving of the characters on the master sheet and simultaneous transference of the dissolvable dye to the copy sheet and the latter referring to a chemical reaction between the liquid or solvent and the matter from which the master sheet characters are formed.

It is an object of this invention to provide a combined feeding, positioning and moistening means which overcomes the above objections.

It is another object of this invention to provide, in combination with a pair of intermittently rotating moistening rolls, means to remove the accumulation of moistune from the bite thereof.

Still another object is to provide improved suction means for removing moisture from the lower feed roll.

According to my invention, I provide, as a lower feed roll, a hollow porous roll which, due to its capillarity will rapidly absorb any accumulation of moisture at the bite, together with means for maintaining the interior of said feed roll at a sub-atmospheric pressure to the end that there will be a movement of liquid from the periphery of the roll to the hollow interior thereof.

Still another object is to provide, in moistening means of the type indicated, a yielding supporting means for the lower feed roll in combination with a coupling between the lower feed roll and a pump which will not prevent up and down movement of the yieldingly supported roll.

Other features, objects, and advantages will become apparent as the description proceeds. 7

With reference now to the accompanying drawings in which like reference numerals designate like parts:

Fig. l is a longitudinal sectional elevation through a duplicating machine showing a preferred embodiment of my invention;

Fig. 2 is a transverse vertical section taken along line 22 of Fig. I;

Fig. 3 is an enlarged vertical section, similar to Fig. 2, but showing certain details of the construction of the feeding and moistening rolls;

Fig. 4 is a vertical section taken along line 4-4 of Fig. 3;

Fig. 5 is a plan section taken along line 5-5 of Fig. 3;

Fig. 6 is a vertical elevation taken along line 6-6 of Fig. 5; and

Fig. '7 is a detailed elevation of the leaf spring shown in Fig. 6.

With reference now to Figs. 1 and 2, the reference nomerals 10 and 11 designate a pair of spaced side plates which are connected to each other by a base member 12, and by other transverse structural members, not shown. Suitably journaled in the side plates 18 and 11 is a shaft 13 upon which a drum 14 is mounted. Suitable means, not shown, are provided for rotating the drum and drum shaft.

Located beneath the drum is a pressure roll 15 which is journaled in pivotally mounted cradles 16. Suitable means, not shown, are provided to maintain the cradles 16 in such position that the pressure roll 15 engages the drum with substantial pressure in order to provide the desired duplicating action.

Disposed in front of the drum and pressure roll, which is to the left, as shown in Fig. 1, and in substantial alignment with the bite thereof. is a pair of combined feeding, positioning and moistening rolls 17 and 18. The upper feed roll, as shown in Figs. 24, comprises an outer portion 19, formed of a comparatively resilient material, such as soft rubber, soft neoprene, or other compliant rubber-like material and a core 20. The core is journaled in the side plates and 11 by suitable bearing units 21. The upper feed roll 17 is driven, through an overrunning clutch unit 54 by suitable driving mechanism, not shown, which meshes with the gear 53, which is connected to the driving element of the overrunning clutch unit 54.

The lower feed roll .18 comprises a hollow porous cylinder 22 which is mounted on a core 23 by means of rubber end members 24 in the form of plugs which serve as spacers to maintain a concentric relationship between the elements 22 and 23. Thus, a space 52 is provided within the interior of the lower feed roll 18 in which the solvent can accumulate.

As shown in Fig. 3, one end of the core 23 is provided with a passageway 25, the inner end of which communicates with intersecting bores 26, so as to provide communication between the space 52 and a suitable fitting, to be described hereinafter.

The extended and reduced ends of the core 23 are provided with bushings 29 which rest in cradles 27 which are pivoted at 28. A suitable spring 30 is provided which biases the cradles 27 in the counterclockwise direction, as shown in Fig. 1, so that the lower feed roll 18 is yieldingly supported and held against the upper feed roll 17. This yielding support permits movement of the lower feed roll so as to accommodate itself to copy sheets of various thickness which may be fed between the rolls 17 and 18, and it also permits the lower feed roll to accommodate itself to any eccentricity of the surface of the hollow porous cylinder 22.

Means are provided for applying a thin film of moisture or solvent to the surface of the upper feed roll 17 as it is rotated. This means includes a perforated spray tube 31 which, as shown in Figs. 1 and 2, is located above the upper feed roll 17. A conduit 32 extends between the perforated spray tube 31 and a suitable pump 33, and the conduit 34 extends between the pump 33 and a supply tank 35. In the particular embodiment shown, the tank is provided with a vented cap 36. In operation, the pump 33 is actuated by the rotation of the drum, once each revolution, so as to cause a measured amount of solvent to be sprayed onto the upper feed roll 17 once during each drum revolution. An example of such pump is shown in Quirk Patent 2,659,303, dated November 17, 1953.

In order to distribute the solvent uniformly over the roll and throughout the operating cycle, a wiper 38 is provided which is mounted in suitable supporting means 39. The wiper is made of felt or other suitable fibrous material and is held, by the supporting means 39, in contact with the upper feed roll 17, to the end that a film of solvent of the desired thickness. may be applied to the surface of the upper feed roll for transference to the surface of the copy sheets which are contacted and fed thereby.

As pointed out above, any excess of liquid which collects on the lower feed roll 18 is absorbed by the porous material 22 from which the feed roll is made. and this liquid collects in the space 52. Means, shown in Figs 2 and 3, are provided to withdraw this liquid from the space 52 and to return it to the supply tank 35. Such means comprises a suction pump 40 together with a conduit 41 extending from the pump to the supply tank 35, at a point above the liquid level therein, and a conduit 42 extending from the pump to a coupling in the form of a tube 43.

One end of the tube 43 is received within the passageway 25, and the other end is received within the conduit 42. The tube 43 is provided with an enlarged central portion 44, against the inner end of which is disposed a thrust Washer 45 and an O ring 46 of neoprene or the like.

A leaf spring 47 is secured by a screw 48 to the side plate 11 and bears against the end of the portion 44 so that the O ring 46 will be confined between the end surface of the core 23 and the thrust washer 45. Thus, a h

seal is provided which permits the core 23 to be rotated, without causing rotation of the tube 43, and which seal maintains the sub-atmospheric pressure developedby the pump 40 within the passageway 25, the tube 43, and the conduit 42.

As shown in Figs. 6 and '7, the leaf spring is provided with a non-circular opening 49 which conforms in shape to the slabbed end 50 of the enlarged portion 44. Thus, the leaf spring fits over the slabbed end and prevents the tube 43 from rotating. The tube 43 is easily removed by unscrewing the screw 48, which permits the tube 43 to be withdrawn from the passageway 25. Then the lower feed roll 18 can be lifted off of the cradles 27.

The tube 43 and its enlarged central portion 44 extend through an opening 51 formed in the side plate 11, this opening being sufficiently larger than the dimensions of the central portion 44 as to permit the desired up and down movement of the lower feed roll 18 and the cradles 27. Thus, a coupling is provided between the lower feed roll 18 and the conduit 42 which permits both rotational and translational movement of the lower feed roll, since the conduit 42 is flexible.

In operation, the upper feed roll 17 is intermittently driven from the drum 14 by suitable means, an example of which is shown and described in Levin Patent No. 2,661,686, dated December 8, 1953. The drum 14 may be rotated either continuously or through a single cycle at a time, according to the type of operation desired.

The bite of the feed rolls 17 and 18, when the rolls are stationary, serve to position the leading edge of a copy sheet; then, when the feed rolls 17 and 18 commence their rotation, the copy sheet is fed to the bite of the drum 14 and pressure roll 15. Thereafter, it is not necessary that the gear 53 be positively driven, because the overrunning clutch unit 54 permits the copy sheet to drive the feed rolls. The lower feed roll 18 is rotated by virtue of its pressure contact with the upper feed roll 17.

Even though the copy sheet is considerably narrower than the width of the feed rolls 17 and 18, the moisture will not built up on the surface of the lower feed roll due to its porous nature. The suction pump 40 not only serves to remove the liquid from the space 52, as it collects therein, but it also, the pores having first been saturated, serves to maintain the whole interior of the hollow porous cylinder 22 at a sub-atmospheric pressure. This prevents dripping of the porous feed roll and also facilitates the dissipation and absorption of the bead of liquid which might otherwise collect at the bite.

The suction pump may be actuated by the rotation of the drum in the same manner as pump 33. Any type of pump may be suitable for the purpose of creating the desired suction, such as the bellows type of pump shown in the aforesaid Quirk Patent No. 2,659,303, or a kneading tube type of pump may be employed.

With reference to the leaf spring 47, it will be observed that the screw 48 provides, in effect, a pivotal mounting for the leaf spring which permits a certain degree of up and down movement of the coupling tube 43 with the lower feed roll 18, which feed roll can also be termed a backing roll for the upper feed roll 17.

Although the hollow porous cylinder 22 may be made from any one of a number of ditferent porous materials, I have found that satisfactory results have been obtained by the use of a filter material of the aluminum oxide grain, ceramic bonded type. The desired porosity will depend upon the nature of the liquid; for an alcohol base low surface tension direct process solvent. I have found that a grade 20 filter operates satisfactorily. This grade is stated by the manufacturer, The Carborundurn Company, to have an average pore diameter of .010 inch.

For proper operation, the liquid should wet or fill the pores for the entire length of the roll, and for the entire 360 of the cylinder wall, in order to seal otf the pores so that the roll will hold the suction. When one starts with a dry roll, this condition can be obtained very quickly if the porosity is fine enough as to provide capillarity in the axial direction of the roll. If the pores are too large, this result will not be obtained as rapidly.

On the other hand, if the porosity is too fine, then the roll will not absorb the liquid as rapidly as it would if the pores were larger. Therefore, there is an optimum porosity for different types of liquids and pumps.

It is not necessary that a completely air tight seal be provided for the space 52, that is, the interior of the porous roll. For instance, there may be a certain amount of leakage through or around the elements 45 and 46, and between the outer surface of tube 43 and the surface of the passageway 25, without impairing the desired action. As a matter of fact, a certain amount of air leakage may occur to replace the liquid withdrawn. Also, there may be leakage between the members 24 and their cooperating parts. However, the leakage paths mentioned should alford sufiicient resistance to the passage of air so that the desired sub-atmospheric pressure within the space 52 may easily be maintained by the suction pump 40 in order to prevent dripping from the lower half of the roll.

Although only a preferred embodiment of my invention has been shown and described herein, it will be understood that various modifications and changes may be shown without departing from the spirit of my invention as pointed out in the appended claims.

I claim:

1. In a duplicating machine having a pair of side plates and a moistening roll journalled therein, the combination of a backing roll disposed beneath said moistening roll, means for yieldingly supporting said backing roll for cooperation with said moistening roll, said backing roll comprising a hollow porous cylinder, a concentric inner core having end portions extending beyond said cylinder and journalled in said supporting means, and impervious end members spacing said cylinder from said core and providing an enclosed chamber within said cylinder, said core having an axial passageway in one of said end portions communicating at its inner end with said chamber, a coupling in the form of a tube having one end received within said axial passageway, and having a central enlarged portion, sealing means confined between said central enlarged portion and the end surface of said core, said coupling extending through an opening in said side frame, a leaf spring mounted on said side frame and bearing against said coupling in an axial direction in order to maintain the etfectiveness of said sealing means, said leaf spring having a portion at one end engaging said coupling to restrain the same against rotation with said backing roll, the other end being pivotally mounted on said side frame to permit up and down movement of said backing roll with said supporting means.

2. In a duplicating machine having a pair of side plates and a moistening roll journalled therein, the combination of a backing roll disposed beneath said moistening roll, means for yieldingly supporting said backing roll for cooperation with said moistening roll, said backing roll comprising a hollow porous cylinder having reduced end portions journalled in said supporting means, an axial passageway in one of said end portions communicating at its inner end with the interior of said cylinder, 3 coupling in the form of a tube having one end received within said axial passageway, and having a central enlarged portion, sealing means confined between said central enlarged portion and the end surface of one of said reduced end portions, said coupling extending through an opening in said side frame, and a leaf spring mounted on said side frame and bearing against said coupling in an axial direction in order to maintain the effectiveness of said sealing means, said leaf spring also engaging said coupling to restrain the same against rotation with said backing roll.

3. In a duplicating machine having a rotatable moistening roll, the combination of a backing roll disposed beneath said moistening roll, means for yieldingly supporting said backing roll for cooperation with said moistening roll, said backing roll comprising a hollow porous cylinder, a concentric inner core having end portions extending belond said cylinder and journalled in said supporting means, and end members spacing said cylinder from said core and providing an enclosed chamber within said cylinder, said core having an axial passageway in one of said end portions communicating at its inner end with said chamber, a coupling in the form of a tube having one end received within said axial passageway, means engaging said coupling to prevent the same from rotating, sealing means between said coupling and said backing roll, and a source of sub-atmospheric pressure connected to said coupling.

4. Moistening means for a duplicating machine comprising a pair of cooperating feeding and moistening rolls, means for applying a thin film of liquid to the surface of one of said rolls, the other one of said rolls being a hollow porous roll, said hollow porous roll comprising a hollow porous cylinder having openings of capillary dimensions around the full 360 of its periphery, and end members cooperating with said cylinder to provide an enclosed chamber bounded on 360 of its periphery by a capillary wall, and suction means communicating with the interior of said chamber and maintaining said interior at a subatmospheric pressure so that liquid which would otherwise accumulate at the bite of said rolls will pass through said capillary wall into said chamber and accumulate within said chamber, said accumulated liquid and the capillary of said wall cooperating with each other to seal off said capillary openings in order to maintain said sub-atmospheric pressure, said suction means also serving to remove a portion of said accumulated liquid from said chamber.

5. Moistening means as claimed in claim 4 in which said suction means comprises a suction pump, a conduit extending to said suction pump, a coupling connecting said conduit and said hollow porous roll, means to prevent said coupling from rotating, and sealing means between said coupling and said hollow porous roll.

6. Moistening means for a duplicating machine comprising a pair of feeding and moistening rolls positioned one above the other, means for applying a thin film of liquid to the surface of the upper feed roll, the lower feed roll being a hollow porous roll, said hollow porous roll comprising a hollow porous cylinder having openings of capillary dimensions around the full 360 of its pe riphery, and end members cooperating with said cylinder to provide an enclosed chamber bounded on 360 of its periphery by a capilllary wall, and suction means communicating with the interior of said chamber and maintaining said interior at a sub-atmospheric pressure to cause liquid on the top surface of said hollow porous roll to pass through said capillary wall into said chamber and to accumulate within said chamber, said suction means and said capillary wall cooperating with each other to prevent accumulated liquid within said chamber from flowing downwardly through said capillary wall, said suction means also serving to remove a portion of said accumulated liquid from said chamber.

References Cited in the file of this patent UNITED STATES PATENTS Wilderson Nov. 24, 1942

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