US3610499A

US3610499A - Paper-feeding mechanism for photographic printers

Info

Publication number: US3610499A
Application number: US831049A
Authority: US
Inventors: Albert F Gallistel
Original assignee: Pako Corp
Current assignee: Pako Corp
Priority date: 1969-06-06
Filing date: 1969-06-06
Publication date: 1971-10-05
Anticipated expiration: 1988-10-05
Also published as: FR2052357A5; NL7006252A; BE749953A; GB1299283A; CA940152A; SE358479B; DE2015596A1

Abstract

This is an invention which permits precise feeding of a readily adjustable predetermined length of paper progressively in a stepby-step intermittent manner through a photographic printer. This is accomplished by a precisely variable length actuating arm intermittently rotatable through a predetermined constant arc (such as one complete revolution) and connected to a paperfeeding roll assembly for intermittent feeding of the paper through the printer.

Description

United States Patent 1111 3,610,499

[72] Inventor Albert F. Gallistel 1,023,883 4/1912 Scott 226/157 Wayzata, Minn. 2,779,590 1 1957 Seastrom 226/141 x [21] Appl. No. 831,049 3,172,592 3/1965 Norden 226/157 :iled d Jo 5 3 9 7 FOREIGN PATENTS atente ct. Assignee Pako Corporation 1,246,392 1 1/1959 France 226/139 Minneapolis, Minn. Primary Examiner-Allen N. Knowles Assistant Examiner-Gene A. Church Attarney.lohn W. Adams [54] PAPER-FEEDING MECHANISM FOR PHOTOGRAPl-IIC PRINTERS 2 Claims, 4 Drawing Figs.

{52] US. Cl 226/115,

226/157, 226/195 ABSTRACT: This is an invention which permits precise feed- [51] lnLCl B65h 17/04 ing f a read), adjustable predetermined l h f paper Fleld of Search 226/8, 120, progressively i a te b te intermittent manner through a 175 photographic printer. This is accomplished by a precisely vari- [56] References Cited able length actuating arm intermittently rotatable through a predetermined constant arc (such as one complete revolu- UNITED STATES PATENTS tion) and connected to a paper-feeding roll assembly for inter- 2,841,997 7/1958 Maust 226/139 X mittent feeding of the paper through the printer.

PATENTEUncI 5am 51 99 sum 1 0F 2 FIE! .2

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sum 2 nr 2 )lnWW 1 PAPER-FEEDING MECHANISM FOR PHOTGGRAPIIIC PRINTERS In the past, feeding devices for photographic printers have been relatively difficult to adjust for feeding an infinite range of different size prints through the printer and for the most part have not been sufficiently accurate to prevent substantial waste of the printing paper.

The principal object of the present invention is to provide a precisely and easily adjustable step-by-step intermittent drive for the feeding roll assembly which will feed an infinite range of extremely accurate incremental lengths of the printing paper through the printer thus substantially eliminating waste and designed to produce relatively slow starting and stopping feeding speeds which are gradually accelerated to a maximum speed and gradually decelerated therefrom.

This object and others will more fully appear from the following description made in connection with the accompanying drawing wherein like reference characters refer to similar parts throughout the several views, and in which:

FIG. 1 is a diagrammatic rear elevational view of a supply and takeup mechanism for a photographic printer including my controllably adjustable feeding mechanism;

FIG. 2 is a somewhat more detailed rear view of the feeding mechanism, per se;

FIG. 3 is a top plan view of the structure shown in FIG. 2 and as viewed substantially from the line 3-3 of FIG. 2; and,

FIG. 4 is an enlarged view of the control arm, per so, as viewed substantially from the line 4-4 of FIG. 3 with the arm rotated approximately 90 from its starting position.

FIG. 1 shows diagrammatically the paper supply, feeding and takeup mechanisms for intermittently feeding precisely predetermined lengths of photographic paper through a printer. A supply roll or magazine carries the supply of paper to be fed through the printer. A supply mechanism 1 1 of conventional construction (details not shown) is provided for withdrawing lengths of paper from the roll 10 and providing a slack loop 120 in the web of paper 12 as it passes to the

feeding rolls

13 and 14. An identifying number stamp mechanism 15 of conventional design numbers each print as the paper is fed through the printer. Tensioning rolls l6 and 17 are slightly larger in diameter than

rolls

13 and 14 to maintain a predetermined desired tension on the paper while the same is disposed in the exposure area A during the printing process. A takeup roll 18 is provided with a suitable takeup mechanism 19 of conventional design (details not shown).

,The

feeding rolls

13 and 14 and tensioning rolls l6 and 17 are positively driven as by a chain and sprocket drive. The chain is designated by the numeral 20 and is trained about a pair of sprockets 14a and 170 respectively attached in fixed relation to the

driving rolls

14 and 15, and the rolls l3 and 17 are driven from

rolls

14 and 15 as by sets of meshed gears.

The chain 20 is provided with a return spring 21 connected with one end thereof. The other end of the chain is connected with an actuating arm 22 having an adjusting slide 23 mounted I for adjustable sliding movement longitudinally of said arm. An

elongated worm 24 is journaled for rotation on said arm and suitable means for producing rotation thereof is provided such as the bevel gears 25 and a rotatable control knob 26. The slide 23 is meshed with the worm 24 so that rotation of the worm will produce longitudinal shifting movement of the slide back and forth along the length of the arm 22. The slide is pivotally connected with the chain 20 as by the pivot pin 23a and controls the effective length of the actuating arm 22. The arm is provided with a numbered scale to indicated the amount of paper fed through the feeding rollers and tensioning rollers for each rotation of the arm. A pointer 23b is provided on the slide to facilitate accurate reading of the numbered scale as best shown in FIG. 4.

i I In the form shown the arm 22 is rotated through a complete circle by a single revolution type clutch mechanism 27 to which power is supplied from an electric motor 28. In the mechanism illustrated an endless chain and sprocket drive 29 connects the output shaft of the motor 28 with the clutch 27 and drive shaft 30 which is keyed to the arm 22 as best shown in FIG. 4.

A single revolution type clutch 27 has a latch or stopping pawl 32 which positively engages the shoulder on the stop roller 33 as best shown in FIG. 2. A solenoid 34 is provided to release the pawl 32 from the shoulder at the beginning of each revolution of the arm 22. An antibacklash-overrunning clutch mechanism 34a is also provided on shaft 30 to prevent backlash movement of the shaft at the end of eachrevolution as best shown in FIG. 3. An overrunning clutch mechanism 34 is also provided at the end of each of the

rollers

14 and 17 which prevents reverse rotation of each of said rollers during the return portion of the actuating stroke of the chain 20.

The starting position of the arm 22 is vertical and an idler sprocket 31 is provided directly above the axis 30 of the arm 22. At the beginning of the rotational movement of the arm 22 the increment of movement of the chain will be at a minimum for each degree of rotational arc of the arm. The speed of the chain will accelerate gradually to its maximum speed at a point when the arm reaches the horizontal position at the end of the first quarter of the complete revolution and this is approximately its position as viewed in FIG. 4. The speed of the chain will gradually diminish for the next of arc. The chain 20 will then be returned by the spring 21 to its starting position under the control of the arm 22. The overrunning clutches 35 permit return of the chain without reversing the

rollers

14 and 17. The rate of acceleration and deceleration of the chain 20 will be at a minimum at the beginning and end of the actuating stroke and also at the beginning and end of the return stroke. This imparts a smoother driving action to the chain during each actuation thereof. A pair of stepped-guiding

rollers

32 and 33 disposed outside of the

rollers

13, 14 and 16 and I7 respectively provide guiding shoulders for engaging the edges of the paper 12 and keep the same centered as is passes through the exposure area A. The steps correspond to the various standard width papers conventionally used for photographic print paper.

A conventional control circuit (not shown) is provided to expose the paper after each revolution of the arm 22 and after each such exposure the am is again actuated.

Occasionally it is necessary to run a series of test prints and instead of using full lengths of paper for such a test which would be very wasteful, it is desirable to provide a short stroke paper feed by which only a short length of paper will be exposed for test purposes. One instance where such a series of test prints would be used is when a new batch of paper is being put into the printer. The paper manufacturer cannot maintain absolute consistency of the emulsion on the print paper from batch to batch and therefore when a new batch is to be used the operator will run a series of test prints with prescribed test variations in the print exposure conditions in order to obtain an optimum setting for that particular emulsion. Such a short stroke paper feed could be provided by a solenoid 36 connected to a stirrup 37 which surrounds a portion of the lower run of the chain 20 as best shown in FIGS. 1 and 2. When the solenoid 36 is actuated this stirrup will pull down on the chain and cause only a short increment of paper to be advanced. A return spring 36a returns the stirrup to its normal position wherein the chain 20 will pass freely back and forth therethrough upon normal operation of the arm feeding mechanism as described. The exposure area A is reduced in size for the test runs as by opaque slides (not shown) movable into and out of the area A.

It will be seen that I have provided a relatively simple yet highly effective method and apparatus for precisely varying the intermittent step-by-step feeding of photographic paper from a supply roller into the exposure area A from which it is ultimately discharged.

It will, of course, be understood that various changes may be made in the form, details, arrangement, and proportion of the parts without departing. from the scope of the invention, which generally stated, consists in the matter set forth in the accompanying claims.

What is claimed is:

l. in a photographic printer of the type having paper supply mechanism and a takeup mechanism with an exposure area receiving photographic printing paper to be exposed;

an adjustable paper-feeding mechanism comprising a pair of feeding rollers having driving engagement with said paper,

a driving mechanism including an actuating arm having positive driving connection with at least one of said feeding rollers,

power means for rotating said arm through a predetermined are,

means for precisely varying the effective length of said actuating am to controllably vary the amount of rotation of said feeding rollers produced by said arm when the same is rotated through said predetermined are to precisely control the length of paper fed into the exposure area by said feeding rollers,

means for maintaining the desired predetermined tension in said paper while the same is in said exposure area, and

a short feed mechanism connected with said feeding rollers for rotating the same through an are substantially less than the are produced by said actuating arm.

2. in a photographic printer of the type having paper supply mechanism and a takeup mechanism with an exposure area receiving photographic printing paper to be exposed;

a driving mechanism including an actuating arm having positive-driving connection with at least one of said feeding rollers,

power means for rotating said arm through a predetermined are,

means for precisely varying the effective length of said actuating arm to controllably vary the amount of rotation of said feeding rollers produced by said arm when the same is rotated through said predetermined arc to precisely control the length of paper fed into the exposure area by said feeding rollers,

said tension-maintaining means consisting in a pair of tensioning rollers of slightly greater diameter than said feeding rollers and disposed on the opposite side of said exposure area from said feeding rollers and also having positive-driving connection with said arm and said paper to produce the same rotational speed as said feeding rollers.

Claims

1. In a photographic printer of the type having paper supply mechanism and a takeup mechanism with an exposure area receiving photographic printing paper to be exposed; an adjustable paper-feeding mechanism comprising a pair of feeding rollers having driving engagement with said paper, a driving mechanism including an actuating arm having positive driving connection with at least one of said feeding rollers, power means for rotating said arm through a predetermined arc, means for precisely varying the effective length of said actuating arm to controllably vary the amount of rotation of said feeding rollers produced by said arm when the same is rotated through said predetermined arc to precisely control the length of paper fed into the exposure area by said feeding rollers, means for maintaining the desired predetermined tension in said paper while the same is in said exposure area, and a short feed mechanism connected with said feeding rollers for rotating the same through an arc substantially less than the arc produced by said actuating arm.

2. In a photographic printer of the type having paper supply mechanism and a takeup mechanism with an exposure area receiving photographic printing paper to be exposed; an adjustable paper-feeding mechanism comprising a pair of feeding rollers having driving engagement with said paper, a driving mechanism including an actuating arm having positive-driving connection with at least one of said feeding rollers, power means for rotating said arm through a predetermined arc, means for precisely varying the effective length of said actuating arm to controllably vary the amount of rotation of said feeding rollers produced by said arm when the same is rotated through said predetermined arc to precisely control the length of paper fed into the exposure area by said feeding rollers, means for maintaining the desired predetermined tension in said paper while the same is in said exposure area, and said tension-maintaining means consisting in a pair of tensioning rollers of slightly greater diameter than said feeding rollers and disposed on the opposite side of said exposure area from said feeding rollers and also having positive-driving connection with said arm and said paper to produce the same rotational speed as said feeding rollers.