US3033433A

US3033433A - Drive system for whiteprint machines

Info

Publication number: US3033433A
Application number: US843745A
Authority: US
Inventors: Joseph J Kottman; Robert C Goodman
Original assignee: General Aniline and Film Corp
Current assignee: GAF Chemicals Corp
Priority date: 1959-10-01
Filing date: 1959-10-01
Publication date: 1962-05-08
Anticipated expiration: 1979-05-08
Also published as: GB915726A

Description

May 8, 1962 Filed Oct.

J. J. KOTTMAN ETAL DRIVE SYSTEM FOR WHITEPRINT MACHINES 3 Sheets-Sheet 1 FIG.I

mmvrons JOSEPH .1- K01 FMAN ROBERTCGOODMAN.

to M

ATTORNEVS May 8, 1962 J. J. KOTTMAN ETAL 3,033,433

DRIVE SYSTEM FOR WHITEPRINT MACHINES 5 Sheets-Sheet 2 Filed Oct. 1, 1959 INVENTORS JOSEPH J. KOTTMAN ROBERT c. GOODMAN ATTORNEYS May 8, 1962 J. J. KOTTMAN ETAL DRIVE SYSTEM FOR WHITEPRINT MACHINES 5 Sheets-Sheet 3 Filed Oct. 1, 1959 FIG.3

INV EN TORS JOSEPH J. KOTT'MAN ROBERT C.GOODMAN BY 2 1 ATTORNEYS Patented May 8, 1962 3,033,433 DRIVE SYSTEM FOR WHTTEEPRINT MACHINES Joseph J. Kottman and Robert C. Goodman, Binghamton, N.Y., assignors to General Aniline & Fiirn Corporation,

New York, N.Y., a corporation of Delaware Filed Oct. 1, 1959, Ser. No. 843,745 6 Claims. (Cl. 226-408) This invention relates to web feeding or conveying arrangements and, more particularly, to a conveyor system useful in reproduction apparatus for processing a continuous length of light sensitive sheet material.

In reproduction apparatus of the above type, the light sensitive material is generally exposed over a rotating translucent printing cylinder and thereafter is passed in contact with the surface of a developing tank. A typical example of such apparatus is a diazotype duplicating machine wherein the light sensitive sheet material is generally conveyed between a plurality of conveyor belts having cengaging surfaces. The handling of the sheet material may require several distinct belt assemblies each serving a particular area of the machine. These assemblies utilize a cluster of rollers strategically disposed over which the endless conveyor belts are arranged to travel. The belt system-s are generally driven from a single power source to assure a uniform drive for each belt assembly.

Handling of individual sheets does not pose a synchronization problem between the successive conveyor belt systems inasmuch as the length of the sheet is relatively short so that the material conveyed from one system onto the other is not subjected to undue tension. On the other hand, in reproduction machines called upon to process a continuous length of sensitized paper taken from a supply roll which may be located in the machine, the paper feed over the conveyor belt systems poses a serious problem of synchronization. The reason for this is that both the printer and the developer section drives are hard drives, that is, they are not torque sensitive.

Heretofore, speed synchronization between these two drives has been attempted by the use of an adjustable pitch pulley. It is a well known fact, however, that with two hard drives in a web handling system, in which the web is tightly held at each of two positively driven points by snubbing action, the speed synchronization must be automatic. Such synchronization is accomplished either by sensing web tension or by a signal from a floating roller which in turn controls the speed. These types of auto matic synchronizations are too complex for use in reproduction apparatus. Without an automatic sensing device acting upon the speed synchronization mechanism, the web tension will either increase .or decrease. In other words, it will creep out of control in either direction. The simple expedient of a manually adjustable pitch pulley is inadequate, requiring frequent adjustments even for relatively short lengths ofweb.

It is accordingly a primary object of this invention to provide a drive system for conveyors handling continuous lengths of web material in which speed synchronization is eliminated.

It is another object of this invention to provide a drive system for conveyors in which the speed ratio is automatically controlled by the web.

A particular feature of this invention is that the automatic control of the speed ratio between the various drives of a conveyor system is accomplished by simple mechanisms which may be installed in existing apparatus.

Other objects and features will be apparent from the following description of the invention, pointed out in particularity, in the appended claims and taken in connection with the accompanying drawings in which; FIG- URE 2 is a side elevational schematic representation of a reproduction machine showing the power drive of the conveyor systems. FIGURE 1 is a similar view showing the arrangement of the conveyor belts. FIGURE 3 is a partial front view showing the main drive connections of the outfeed and infeed rollers and an ancillary drive for the latter. FIGURE 4 is a sectional view of the unidirectional clutch shovm in FIGURE 3, taken along lines 4-4.

Referring to the drawings, let us consider first, the general arrangements of the conveyor belt systems illustrated in FIGURE 1. For the sake of simplicity only such portions of the reproduction apparatus are shown which are material to the understanding of the invention which, as stated before, is chiefly concerned with improvements of the paper feed and conveying mechanism. The various mechanical assemblies of the reproduction machine are shown within the framework of housing 6. The functional elements of such a reproduction apparatus may be grouped into two main areas; the first is the printing or exposing area which consists of a printing cylinder 8 over which the sensitized material must be passed in order to be exposed by a suitable light source 9 located within the cylinder. This is accomplished by a conveyor belt system consisting of the endless belts 10 arranged to follow a certain path by means of strategically placed

rollers

11, 12, 13, 14, 15, and 16. In the schematic illustration of FIGURE 1, the conveyor belts are represented by single continuous lines. It is, of course, understood that in practice, several belts are placed side by side over the surface of the printing cylinder in order to handle a certain width of sheet material. dle 54" size sheets, there may be 27 belts running side by side, each approximately 2 wide to cover the area.

In order to constrain the sheet material to follow the path of the belts 10, two sets of endless belts 1 7 and 18 are placed over strategically located

rollers

19, 20, 21, 22, 23, and 24, respectively. Belts 17 tensioned between rollers 19 and 2d are positioned to have co-engaging surfaces with the belts 19 whereas the belts 18- are placed over rollers 21, 22., 23, and 24, so as to have co-engaging surfaces with the belts 10 facing the rearward portion of the machine. The above described belt system handles the exposing portion of the apparatus. The rollers 11 and 19 are placed near the infeed table 26 over which the sensitized sheet material 27 is fed from a supply roll 28. Thus, the roller 11, coacting with the roller 19, is generally referred to as the infeed roller.

The developing area of the apparatus is located in the rear portion and consists of a developing tank 30 which is a triangularly shaped structure having a perforated wall 31 over which, and in contact therewith, the exposing sheet material must pass so that the vapors generated within the tank, exuding from the perforated wall 31, contact the material and thereby develop the latent image. In oder to pass the sensitized material from the exposing area to the developing area and over the perforated wall 31, a second conveyor belt system is used comprising a single belt of gas impermeable material which overlies the perforated Wall 31 thereby preventing the escape of the developing vapor. For this reason, it is termed the sealing sleeve 33. The latter is held in position by the

rollers

34 and 35. The roller 34 is located in close proximity to the roller 14, so as to allow the sensitized material from the conveyor system of the exposure area to pass under the sealing sleeve 33. A suitable deflector plate 36 closes the gap between the

rollers

14 and 34 to guide the passage of the sensitized material. The latter gripped by the sealing sleeve 33 is then constrained to follow over the perforated wall 31 of the developing tank 39 until it contacts a third belt system consisting of the endless conveyor belt 38 which travels over

rollers

39 and 40 and constrains the material to follow the path for delivery In machines which hana through an exit opening at the rear of the machine. Suitable

sheet guiding plates

42 and 43 cooperate with the belt 38 for the guidance of the sheet material. When the machine is used to process cut sheets instead of continuous length material, delivery may be effected onto a tray 45 by altering the course so as to avoid the path directed by the guide plate 42. The means for making the selection of the delivery are not shown here inasmuch as this feature has nothing to do with the present invention.

Referring to FIGURE 2, the power drive of the rollers of the conveyor systems is indicated by chain belts interconnecting the drive rollers from a single power source comprising the motor 46 driving the chain 48 which engages the idler pinions 49, G, and 51, and the pinion 39 of the roller 39, as well as the idler 52, and the pinion of the roller 35. The pinion 35 is of dual construction (reference 59 FIG. 3) so as to accommodate the chain 53 which drives the pinion 54, as well as the pinion 11' of the roller 11. It is seen that a direct drive is provided by this arrangement for the infeed roller 11 which is the drive roller of the belt system, serving the exposure area of the machine and for the roller 35 which is the outfeed roller of the belt system, serving the develo ment portion of the apparatus.

An ancillary drive for the infeed roller 11 is also provided by the chain belt 56. This is more fully illustrated in FIGURE 3 to which reference should now be had.

The important elements of the power drive for the belt systems are shown in this figure in greater detail. To simplify the explanation of the operation of this invention, the conveyor belts have been omitted and only the two hard drives are illustrated. It should be borne in mind that the web 57 is constrained to travel over rollers 11 and 35 due to snubbing action and also due to frictional contact between the co-engaging surfaces of the conveying belts. It was pointed out that the roller 11 is the drive roller for the belt system, serving the exposure area and the roller 35 is the outfeed drive roller of the belt system serving the developing area. The chain 48 drives roller 35 whereas the roller 11 is driven by the chain 53 from the sprocket 59 keyed to the shaft 60 of the roller 35. Chain 53 engages the sprocket 11' of the roller 11. it is seen that the sprocket 11 is not directly keyed to the shaft 62 of roller 11, but is keyed to the drive member 63 of a ball type unidirectional clutch, the driven member 64 of which is keyed to the shaft (ii. The force transmitted by this clutch will take effect only in the direction of infeed or counter-clockwise rotation, by virtue of the closure provided by the balls 65. The direction of rotation is taken with an observer facing the end of the shaft 62. As long as there is a restraining force on roller 11, the clutch will operate to rotate this roller in counterclockwise direction, namely, for the infeed of the web 57 in the direction of the arrow. At the same time, this clutch permits rotation of the roller 11 in a counterclockwise direction at a speed higher than the drive speed provided by the chain 53. The importance of this feature will he explained later in connection with the operation of the drive system.

An ancillary drive for the roller 11 is provided also consisting of a friction clutch '67 mounted on stud 6S aifixed to the inner plate 69 which supports the component elements and moving parts of the machine within the housing thereof. The other end of the stud 68 is supported by means of the bracket 71 affixed also to the inner plate 69. The friction clutch 67 consists of the pinion 5 formerly mentioned in connection with the description of FIGURE 1, which rides freely over the stud 6S and has a face plate 72 which engages friction plate 73 of the pinion 74 which also rotates freely over the stud 68. Placed between the

plates

72 and 73 is a disc 7 5 of resilient material to provide a frictional engagement. The torque of this drive may be adjusted by means of the spring 76, one end of which engages the friction plate 77 of the clutch 67 so as to press against the pinion 54. A friction disc 75, similar to the disc 75, is placed between the engaging surfaces.

i The spring 76 may be corn-pressed by turning the knurled knob 78 which is in threaded engagement with the stud 68. The pinion 74 drives the pinion 80 which is keyed to the shaft 62 of the roller 11 by means of the chain 56 referred to in FIGURE 2.

Considering the operation of the drive, the two main conveyor belt systems, namely, the one which feeds around the printing cylinder 8 and the one which feeds over the developing tank 39 are driven by the motor 46. In this manner a uniform drive is established as far as any changes in speed of the motor is concerned. As a matter of fact, the speed of the motor is usually controllable in order to permit a variable feed over the printing cylinder to allow for a variable exposure time. Originals of greater density require more exposure time, consequently, a slower speed must be set for the infeed belt system.

It may be mentioned here that the original, a copy of which is to be made, is placed over the sensitized material 27 on the infeed table 26 and is fed in contact with the material between rollers 11 and 19 and by means of the belt system is passed around the printing cylinder 8. Since after exposure, the original must not pass over the developing tank, means are provided for diverting its path. This is accomplished by air suction as, for example, the suction chamber 82 having a perforated wall 83 around which an endless conveyor belt 84 of porous material is arranged to move by means of the

rollers

85 and 86. The original, thus adhering to the belt 84, is separated and deposited into a receiving tray 87. To maintain the adherence of the sensitized material 27 to the conveyor belt 10 at the vertical portion of its travel, at the point where the original is separated, another suction chamber 89 is used having its perforated wall placed against the inner face of the conveyor belts 10. These belts also have perforation to permit air flow. While processing a continuous length of sensitized material, the suction chamber 89 performs the function of keeping the leading edge of the material against the belts 10 until it enters between

conveyor belts

18 and 10. Thereafter the material is handled by the rollers of the conveyor system. However, in processing short lengths of sheet material, the suction chamber 89 has a continuous function to keep the sensitized material against the belts 10.

As mentioned before, the motor drive is directly applied to both the infeed roller 11 and the outfeed roller 35 of the belt systems. It is the salient point of the invention that despite such direct hard drive connections between the two separate belt systems, the speed ratio between the infeed roller 11 and the outfeed roller 35 will be automatically varied, and that such variation is controlled solely by the web material. To illustrate the func tion of this automatic control, let us assume that a. continuous length of sensitized material is traveling through the machine and a greater pull is exerted on the material by the belt system serving the developing area, namely, by the roller 35. This would tend to pull the material at a faster rate than the feed provided by the rotation of the infeed roller 11, and the stress would tear the material. However, as we know, the unidirectional clutch permits counterclockwise rotation of the infeed roller 11 at a speed higher than the drive so that the binding action of this roller on the sensitized material or web is thereby eliminated. This alone, however, would not be adequate unless the web material is strong enough to withstand the force exerted tending to move the conveyor belt sys tent or allow slippage of the material between the conveyor belts 1t). Sensitized paper, as a rule, does not possess sufiicient strength and some assistance is necessary so that the conveyor belt system may be moved by the pull of the material instead of depending on the slippage between the belts 10. This is accomplished by the ancillary drive which in effect is a torque-assist or tendency drive mechanism. This drive, which by-passes the unidirectional clutch, rotates the roller 11 and thus moves the belts 10 thereby aiding the feed of the web material.

The extent of torque of this drive may be set by adjusting the friction clutch 67. This adjustment need only be made at infrequent intervals depending on the type of web material handled, so that web tension should never be greater than What the material can normally sustain. In order to eliminate the possibility of a reversed condition wherein the feed of the roller 11 and its belt system be greater than the outfeed provided by the roller 35, the latter is so dimensioned as to produce a web travel slight- 1y higher (approximately 1 percent) in speed than that of the infeed roller 11. By this means a uniform feed is assured with the clutch and auxiliary drive functioning to vary the speed ratio and maintain a substantially uniform web tension.

When there is a force exerted on the material 57 in the direction of its travel which overrides the unidirectiom al clutch keyed to the shaft 62 of the roller 11, the conveyor belt system consisting of

belts

1d, 17 and 18 are freed from the drive acting on the sprocket 11. The material 57 would then be called upon to move the conveyor belt system. To permit such a movement without straining the material 57, the tendency drive actuated by the friction clutch 67 is permitted to take over. In order to perform the assist function of this drive, the pinions '74 and 80 are so dimensioned as to relative diameter, or number of sprockets to efiect a higher speed of rotation of the roller 11, and, consequently, of the belt system, than normally when driven by the sprocket 11' of the unidirectional clutch. The force needed to effect the tendency drive is regulated by the friction of the clutch 67 which may be adjusted, as mentioned before, by means of the compression of the spring 76.

We claim:

1. In a reproduction apparatus wherein a continuous length of light sensitive sheet material is passed over an exposing area and subsequently over a developing area between two sets of endless conveyor belt systems each serving one of said areas and each having a drive roller and a plurality of guide rollers, power means for driving said belt systems including a motor connected to said drive roller of one of said systems, rotary power transfer means for directly driving said drive roller of said second system from the driven roller of said first system, said last mentioned means including a unidirectional coupling element and ancillary rotary power transfer means connected between said first and said second belt systems, said ancillary power means by-passing said unidirectional coupling element and having adjustable power transfer characteristics.

2. In a reproduction apparatus wherein a continuous length of light sensitive sheet material is passed over an exposing area and subsequently over a developing area between two sets of endless conveyor belt systems each serving one of said areas and each having a drive roller and a plurality of guide rollers, each of said drive rollers having a shaft, power means for driving said belt systems including a motor connected to the shaft of said drive roller of one of said systems, rotary power transfer means for directly driving the shaft of said drive roller of said second system from the driven roller of said first system, said last mentioned means including a unidirectional coupling element aifixed to the shaft of said drive roller of said second system and ancillary rotary power transfer means connected between said first and said second belt systems, said ancillary power means lay-passing said unidirectional coupling element and having adjustable power transfer characteristics.

3. In a reproduction apparatus wherein a continuous length of light sensitive sheet material is passed over an exposing area and subsequently over a developing area between two separate endless conveyor belt systems each serving one of said areas and each having a drive roller and a plurality of guide rollers, each of said drive rollers having a shaft, power means for driving said belt systems including a motor connected to the shaft of said drive roller of one of said systems, rotary power transfer means for directly driving the shaft of said drive roller of said second system from t1 e driven roller of said first sy tem, said last mentioned means including a unidirectiona1 coupling element aflixed to the shaft of said drive roller of said second system and ancillary rotary power drive connected between said first and said second belt systems, said ancillary drive by-passing said unidirectional coupling element and including an adjustable friction clutch mechanism for regulating the torque thereof.

4. In a reproduction apparatus wherein a continuous length of light sensitive sheet material is passed over an exposing area and subsequently over a developing area between two separate endless conveyor belt systems each serving one of said areas and each having a drive roller and a plurality of guide rollers, each of said drive rollers having a shaft, a motor for driving said shaft of said drive roller of the conveyor belt system serving said developing area, said last mentioned belt system being the outfeed of said apparatus, a pinion on said shaft, a unidirectional clutch on said shaft of said drive roller of the belt system serving said exposing area and being the infeed of said apparatus, a chain belt interconnecting said pinion and said clutch, said clutch being operable in the direction of infeed rotation of said roller and an auxiliary drive interconnecting said infeed roller and said outfeed roller including an adjustable torque friction clutch.

5. In a reproduction apparatus wherein a continuous length of light sensitive sheet material is passed over an exposing area and subsequently over a developing area between two separate endless conveyor belt systems each serving one of said areas and each having a drive roller and a plurality of guide rollers, each of said drive rollers having a shaft, a motor for driving said shaft of said drive roller of the conveyor belt system serving the developing area, said belt system being the o-utfeed of said apparatus, a pinion on said shaft, a unidirectional clutch on said shaft of the drive roller of the belt system serving the exposing area and being the infeed of said apparatus, a chain belt interconnecting said pinion and said clutch, said clutch being operable in the direction of infeed rotation of said roller, an auxiliary drive including a, friction clutch between said chain belt and said shaft of said infeed drive roller, said auxiliary drive by-passing said unidirectional clutch.

6. In a reproduction apparatus wherein a continuous length of light sensitive sheet material is passed over an exposing area and subsequently over a developing area between two separate endless conveyor belt systems each serving one of said areas and each having a drive roller and a plurality of guide rollers, each of said drive rollers having a shaft, a motor for driving said shaft of said drive roller of the conveyor belt system serving said developing area, said belt system being the outfeed of said apparatus, a pinion on saidtshaft, a unidirectional clutch and a spur gear on said shaft of said drive roller of said belt system serving said exposing area and being the infeed of said apparatus, a chain belt interconnecting said pinion and said clutch, said clutch being operable in the direction of infeed rotation of said roller, an auxiliary drive including a clutch having a driven element and a friction coupled drive element, said driven element having a pinion engaging said chain belt and said drive element having a pinion and an endless chain belt engaging said spur gear.

References Cited in the file of this patent UNITED STATES PATENTS 2,001,345 Forty May 14, 1935 2,259,139 Oesinghaus Oct. 14, 1941 2,292,521 Horn Aug. 11, 1942 2,970,788 Warncke Feb. 7, 1961