US978955A

US978955A - Photographic-printing machine.

Info

Publication number: US978955A
Application number: US38398407A
Authority: US
Inventors: Fred Park Stevens
Original assignee: JOHN ARTHUR EDDY
Current assignee: JOHN ARTHUR EDDY
Priority date: 1907-07-16
Filing date: 1907-07-16
Publication date: 1910-12-20
Anticipated expiration: 1927-12-20

Description

' a mmw F. P. STEVENS.

PHOTOGRAPHIO PRINTING MACHINE.

APPLICATION FILED JULY 16, 19o7.-

Patented Dec.20,1910.

I SHEETS-SHEET 1.

av M14400 o c o Y I affoznom F. P. STEVENS.

PHOTOGRAPHIO PRINTING MACHINE. APPLICATION FILED JULY 16,1907.-

978,955. v Patented Dec. 20, 1910.

7 BHEBTB-BHEET 3.

F. P. STEVENS.

PHOTOGBAPHIC PRINTING MACHINE. APPLIOATIOK FILED JULY i6, 1907.

Patented Dec. 20, 1910.

7 SHEETS-SHEET *1.

fiat P'terems,

Suva V607,

F. P. STEVENS.

' PHOTOGRAPHIG PRINTING MACHINE APPLIIOATION FILED JULY 16, 1907.

Wil mosses F. P. STEVENS.

Patented D60. 20, 1910.

7 SHEETS-SHEET 6.

PHOTOGRAPHIG PRINTING MACHINE.

APPLICATION FILED JULY 16, 1907.

a g F IZd P 5,5676/16 vwcm-L'oz q vbbhcooc WWW F. P. STEVENS.

PHOTOGRAPHIG PRINTING MACHINE.

APPLICATION FILED JULY 16, 1907.

Patented Dec. 20, 1910.

7 BHBETSSHEET 7.

UNITED STATES PATENT OFFICE- FBED' PARK STEVENS, OF DENVER, COLORADO, ASSIGNOB OF ONE-HALF TO JOHN I ARTHUR EDDY, OF DENVER, COLORADO.

PHOTOGE A PHIC-PRINTING MACHINE.

- Specification of Letters Patent.

Application filed Jul is, 1907. Serial No. 888,084.

To all whom it may concern:

Be it known that I, FRED P. Srnvnns, a citizen of the United States, residing at Denver, in the city and county of Denver and State of Colorado, have invented a new and useful Photographic-Printing Machine, of which the following is a specification.

This invention relates to means for making photographic prints from negatives, and one of the important objects is to provide novel, simple, practicable and accurate mechaIliSlIl, whereby a negative and paper applied thereto can be exposed for a predetermined period of time, and when said time has expired, the light will be cut oil, and the paper released.

Another and exceedingly important feature of the invention resides in the provision of simple and reliable mechanism for vary- .ing the lengths of exposures.

Still other features relate to the construction and arrangement of the parts, whereby the machine can be manufactured at rela tively small cost, the elements can be easily assembled, and are not liable t0 1I1] 11 I'y or displacement, while the mechanism is entirely accessible.

Another object of the invention is to provide in connection'with the negative holding means, means for holding vignetters and other devices for varying the character 01' the print, said negative holding means being.

so associated with the other mechanism of the machine that it can be readily reached, and after a negative has been positioned on. the negative holding means the devices can be manipulated and adjusted with ease and expedition to secure the desired effects from said negg ative.

An embodiment of the invention that is at present considered the preferable one is illustrated in the accompanying draw1ngs,where- 1n:

Figure 1 is a perspective view of the complete machine. Fig. 2 is a horizontal sectional view therethrough showing the mechanism in bottom plan. Fig. 3 is a sectional view on the line 3-3 of Fig. 2. Fig. 4 is a vertical sectional view at right angles to Fig. 3. Fig. 5 is a rear elevation of the shutter operating means. Fig. 6 is a longitudinal sectional view therethrough. Fig. 7 is an end elevation of the shutter actuating and holding mechanism, showing the shutter during its opening movement. Fig. 8 is a similar view, but illustrating the arts when the shutter is closed. Fig. 9 is a detail view llustrating the motor resetting means when in normal position. Fig. 10 is 'a similar view, but illustrating the parts when the motor is reset and just prior to its release. Fig. 11 is a detail sectional view on the line 11-11 of Fig. 5. Fig. 12 is a plan view of the indicator for the speed controlling means. Fig. 13 is a verticalsectional view therethrough and through the valve mechanism. Fig. 14 is a detail section on the line 14-14 of Fig. 13. Fig. 15 is a bottom plan view of the valve. Fig. 16 is a detail sectional view on the line 16-46 of Fig. 2. Fig. 17 is a detail sectional view on the line 17-17 of Fig. 2. Fig. 18 is a detail view of the hand operating mechanism for the shutter. Fig. 19 is a detail sectional view on the line 19-19 of Fig. 2. Fig. 20 is a detail sec tional view on the line 20- 20 of Fig. 3.

Similar reference numerals designate corresponding parts in all the figures of the drawings.

In the embodiment illustrated, a light in closing casing 21 is employed that may be of any desired character, and preferably incloses an electric lamp (not shown) as is usual in this type of machine. The casing is provided in its side walls and contiguous to its upper end with suitable vent openings 22, and a top 23 closes the upper end of the casing, and is hinged thereto, as illustrated at 2 1; This top is provided with an angular opening 25 therein. Guideposts 2G depend from the under side of the top at the corners of the opening, and a vertically movable frame 27, operating in said opening, has guides 28 slidably engaged with the posts 26 and partially surrounding thesame, the lower ends of the guides being provided with ears 29 that en'ibrace the posts, and coiled springs 30, located. on said posts, have their upper ends bearing against the ears 29 to urge the frame 27 upwardly. The lower ends of the springs rest upon collars 31, and the lower ends of the posts are preferably connected by tie rods 32.

The upper end of the frame constitutes negative holding means, and for this purpose, a plate 33 of comparatively heavy glass is mounted thereomsaid plate thus constituting a support for negatives, one of which is shown at 34. The negative when smaller than the plate is held in place by Patented Dec. 20, 1910.

a suitable mat 35 that is maintained against lateral displacement bly springs 36 secured to the upper end of t e frame, and shown in Fig. 1. The lower portion of the frame constitutes the means for holding vignetters, masks, light diffusing devices and other articles of an analogous nature. For this purpose, guideways 37 and 38 are formed in the side walls of the frame and permit plates, sheets and the like to beinserted when the frame is elevated to a projecting position above the top of the casing. A latch 39, pivoted as shown at 40 to the front portion of the top, engages over the top of the frame, when the same is in its depressed position, to hold it in said position, this latch being provided with an upstanding thumb-piece 41 and having a spring 42 hearing thereagainst to hold it in its operative position. The means for controlling the supply of light to the negative holding means, in the present embodiment of the invention, consists of a shutter that is composed of .oppositely swinging sections 43, the said sections preferably consisting of material that will permit the passage of approximately nonactinic rays of light, while preventing those which are highly actinic. These sections are mounted on suitable frames, which include rock shafts 44 journaled at their ends in depending brackets 45 that are secured to the the vertically moving frame 27. The rock shafts at one end have crank disks 46 secured thereto, and are connected by a rod 47, the connections being such that when one of the shafts is turned in one direction, the

other will be'turned in an opposite direction, and thus the opposite opening and closing movements of the shutter sections is assured.

Both automatic and manualmeans are provided for actuating the shutter. The latterjs disclosed more particularly in Figs. 2, 18 and 19. It will be observed that one of the shafts 44 carries a pinion 48 and has a limited movement thereon, this limited movement being secured by a pin 49, fixed to the shaft and having its projecting portion located in a slot 50 in the pinion. A lever 51, fulcrumed between its ends, as illustrated at 52 in Fig. 18, has its lower end provided with a rack 53 that meshes with the pinion 48. The upper arm 54 of the lever projects through a slot 55 in the casing top 23, and constitutes an actuating handle. A spring 56, secured to the rack and to a suitable portion of the casing or supporting bracket, normally holds the rack 53, and consequently the pinion in a predetermined position. With this mechanism, when the handle 54 is operated, the pinion engaging the pin 49 will cause the shaft 44 to be turned, thereby swinging the shutter shafts 44 of the shutter.

to open position. But if said shutter is moved to open position by the automatic means hereinafter described, the pin 49 beirlig freely movable in the slot 50, will not e ect the operation of the handle. A suitable spring 57, coiled upon one of the shafts 44 and havin one end secured thereto while the other en is secured against movement, serves to return the shutter sections to closed position.

The automatic mechanism now employed for effecting the actuation of the shutter or light controlling means is'as follows. A

hanger 58 is rigldly aflixed to the under side of the .top 23, and 'ournaled therein is a shaft 59, one end 0 the shaft being also journaled in a bracket 60 likewise secured to the under side of the top. A cam track 61, is fastened to one end of the, shaft on one side of the hanger 58, and coiiperates with a roller 62 journaled on an arm 63 that has a limited movement on one of the rock The movement is limited by a pin 64 secured to the shaft and engaged in a slot 65 formed in the hub of the arm 63. A spring 66, secured to said arm and to said shaft, normally holds the hub with one end wall of the slot against the in, as will 'be evident by a comparison of i s. 7, 8 and '17. The shaft 59 1s actuated g; a motor in the form of a coiled spring 67 surrounding a portion of said under side of the top'23 independently of s aft, and as illustrated in Figs. 5 and 6,

having one end secured to a collar 68 that isfast to said shaft, or it may be secured directly to said shaft, while the other end is engaged with a tension varying wheel 69 surrounding but spaced from the shaft and having a hub 69 journaled in the bearing 70 for said shaft, said bearing constituting an integral part of the hanger 58. As illustrated particularly in Fig. 11, the tension varying wheel 69 is held against movement and in difirent positions by a sliding bolt 71 having one end arranged to engage in any of a series of sockets 72 formed in the wheel 69, a spring 73 hearing against the opposite end of the bolt to urge it into said socket. The spring 67 constitutes the principal actuating motor for the shaft 59, but an auxiliary motor is employed for assisting the initial movement of the shaft in opening the shutter, and this auxiliary motor comprises a spring 74 coiled upon the outer end of the bearing 70 and having one end fastened as shown at 75 to the hanger 58. The other .end is arranged to bear against a projection 76 on the inner side of the cam track 61, but this hearing is limited by a pin 77 projecting outwardly from the hanger 58 into the path of movement of the free arm 78 of the spring 74, which bears against the rojection 7 6, as is hereinafter explained in t e description of the operation of the machine. This automatic shutter operating said shaft 59 is released, the sprin mechanism is movable from a set position to open the shutter. In other words, the

shaft 59 must be turned to wind up the

springs

67 and 74 in order to placetension thereupon. When so wound up, the arts, are as illustrated in Figs. 3 and 6. en 67 and 74 operate to return the same an the cam track 61 striking the roller 62 will cause the arm 63 to swing, and the shutterto open. When said cam track has passed the roller 62, the spring 57 will return the shutter to closed position. The means for setting the motor or resetting it after an operation is hereinafter described. Cooperating with the negative holding means, above described, is paper holding'means in the form of a pressure back, and this pressure back comprises sections 79 hinged together, as shown at 80, and having cushioning material 81 upon their under faces. The pressure back is also hinged to the top 23 of the casing independently of the vertically movable frame 27, and to this end, the rear section 79 is provided with rearwardly extendin ears 82 journaled upon a cross bar 83, sai cross bar having vertical collars 84 at its ends that are slidable upon posts 85 rojecting above the upper face of the top. prings 86, mounted on the posts and bearing upon the-collars 84 serve to urge the cross bar to its lowermost position. Other springs 87, coiledu on the cross bar 83, have lifting arms 88 t at are engaged in undercut notches 89 formed in strengthening webs 90 of the pressure back, and these springs serve to elevate the ressure back away from the negative holdmg means.

A lever comprising slidably telescoped

sections

91 and 92 is disposed above the pressure back, and transversely of the sections thereof. The outer section 92 has connections with the pressure back sections 79, and for this purpose, slidably telescoped boxings 93 and 94 are employed. The boxings 93 preferably constitute integral parts of the pressure back sections 79, while the boxings 94 are provided with upstanding spaced cars 95. J ournaled in these ears are collars 96 that are mounted on the outer lever section 92, the front collar being secured against movement thereon by screws 97 The operative movements of the boxings are limited by screws 98 that are threaded through the outer boxings and engage in slots 99 formed in the inner boxings. Springs 100, located within the 'boxings, serve to urge the same outwardly away from each other. The inner section 91 of the lever is provided at its rear end with spaced ears 101 pivotally mounted on a sleeve 102. The sleeve is slidable upon a standard 103 fixed at its lower end to a plate 104, said plate being secured to the casing top 23 and having the posts 85 mounted thereon.

The motor resetting means is connected to' mounted on an integral projecting portion 106 of the bracket 60, and having a cable connection 107 with the rear end of the lever.

This cable, which is preferably, though not necessarily in the form of a chain, wraps upon the carrier 105 when the pressure back is elevated, and it is slightly extensible, a bowed spring 108 constituting the connection between the chain and the rear end of the lever. A spring 109, fastened at one end to the under side of the casing top 23, has its other end connected to a strap 110 that wraps upon the hub 111 of the carrier. This carrier has pivoted thereto a dog 112, and the collar 68 of the shaft 59 is provided with an outstanding finger 113 that has a shoulder 114. These parts are shown particularly in Figs. 3, 9 and 10. A spring 115, engaged with the dog, urges the same int-o interlocking engagement with the shoulder 114 of the arm 113 of the shaft 59 when the pressure back is elevated, and the shaft is in its normal position, as illustrated in Fig. 9, but a depending arm 116 has its lower end 117 disposed in the path of movement of the tail 118 of the dog 112, and serves to swing said dog against the action of the spring so as to disengage it from the shoulder 114, and release the shaft after said shaft has been moved to its set position, or in other words, rotated against the action of the

springs

67 and 74.

The pressure back 79-79, as already explained, is elevated by the springs 88, but

inasmuch as this operation takes place with considerable force, it has been found we pedient to employ cushioning means for stopping the pressure back in its upward movement. In the present embodiment, this cushioning means consists of a plunger 119 carried by the inner end of the lever section 91 and operating in the front end of the lever section 92. A spring 120 is interposed between the plunger 119, and ahead 121 that closes the front end of the lever section 92. When the pressure back is applied, the section 92 will slide outwardly upon the section 91, and air will find its way past the plunger 119. When the pressure back is released, and swings upwardly, the section 91 will slide into the section 92, and this air will slowly pass the plunger as the plunger moves toward the head 121, thus producing a cushioning effect, which effect is height ened by the spring 120 engaged by said plunger 119. has threaded thereinto the upright stem 122 of a depending hook 123, said stem having a knob 124 screwed upon its upper end. A latch 125, pivoted as shown at 126 to the inwardly extending arm of a bracket 127 that The said head furthermore noted,

is fastened to the under side of the top 23, is arranged to interlock with the hook 123 when the pressure back is in position upon the ne ative holding means. It is to be owever, and particularl by reference to Fig. 3 that the interlocking shoulders of the hook 123 and latch 125 are inclined, and this inclination is sufficient to effect the movement of the latch 125 to an inoperative position even against the spring 128 which urges the latch 125 to its interlocking position. A lock, however is employed for said latch, and said lock consists of a bell crank 129 fulcrumed as shown at 130 to the bracket 127 and having an upstanding arm 131 that projects through the top of the casing, and has a suitable handle knob 132. This upright arm 131 is provided with a recessed seat 133 in which a finger 134 of the latch 125 engages. It will be observed that the spring 128 connects the latch and the arm 131, thus drawing them toward each other. It will also be evident that when the finger 134 is engaged in the seat 133, the latch will be locked against rearward movement by the hook 123. The bell crank 129 is furthermore provided with a rearwardly extending arm 135, and pivotally mounted thereon is a swinging dog 136 having a spring 137 for normally holding it in a pre determined position. A projection 138, carried, by the adjacent rock shaft 44, has its path of movement intersected by the lower end of the dog, as will be evident by reference to Fig. 3.

The operation of the mechanism as thus far described, is substantially as follows. The pressure back being in its, elevated position, the chain 107 will be wound upon the carrier 105, as illustrated in Fig. 9, in which case, the dog 112 will be engaged with the shoulder 114 of the arm 113 that is fixed to the shaft 59. The operator places a negative, as 34 in position upon the support 33 and if he desires to alter the printing effect of the same in any manner well known to the art, he disengages the latch 41 from the frame 27, whereupon the springs 30 will elevate said frame. He can thereupon introduce the vignetters, light. diffusing devices or other well known expedients, and after having prepared everything to his satisfaction, the frame 27 is forced downwardly against the action of the springs 30. In

connection with the preparation of the negative, it will be observed that the shutter may be readily opened by manipulatingthe handle 54 shown in Fig. 18. The shutter being again closed, a sheet of sensitized paper is placed upon the negative and the pressure back is then brought down by depressing the knob 124 on the front end of the lever 9192. During this downward movement, and because of the mechanism disclosed, the rear section 79 of the pressure back will be first engaged with the aper, and consequently said paper Wlll be effectively clamped. The operator may then remove his hand from the front portion of the paper and continue the downward movement of the lever, thus bringing the front section of the pressure back into operative position. It will be evident that as the front end of the lever moves downwardly, the rear end will be moved upwardly, and consequently the chain 107 will be correspondingly moved. This will effect the rotation of the carrier 105, carrying the arm 113 with it, and retating the shaft against the action of the

springs

67 and 74. As the front section 79 of the pressure back reaches its above described operative position, the hook 123 of the stem will yield sufficiently to engage with the latch 125, and thus as the engagement takes place to lock the pressure back in its operative position, the tail of the dog 118, as shown in Fig. 10, will reach the lower end 116 of the arm 117. This will cause said dog to swing and disengage from the arm 113, releasing the motor from its set position, and permitting it to rotate the shaft in a reverse direction. movement of the lever and the rotation of the shaft 59 against the action of the

spring

67 and 64 as just described, the cam track 61 will be moved in the direction of the arrow 'shown in Fig. 8, and will pass by the'roller 62. It will be remembered that the arm 63 carrying said roller 62, has a slight movement with respect to the rock shaft 44 carrying said arm. Consequently this movement will now take place and the shutter will not be affected. As the lever, however, reaches its horizontal position, the roller will ride over the end of the cam track and will be in the position shown in Fig. 3. Remembering now that the shaft 59 is released at this point-as above described, and that the springs will react, it will be evident that the cam track 61 will now be moved by said springs in an opposite direction or in other words, in the direction of the arrow shown in Fig. 3. -The.result is that the arm 63 will be swung in an opposite direction, and as it can have no movement independently of the rock shaft 44 in this direction, the shutter will be opened. This opening movement of the shutter requires considerable force because of the leverage and the action of the springs tending to close the shutter. Therefore the auxiliary spring 74 assists the principal spring 67 in this movement. \Vhen, however, the roller 62 rides upon the pe- VVith the downward riphery of the cam track, the additional the shaft, and when-the cam track 61 passes the roller 62, the arm 63 bein free, the spring 57 will act to reclose t e shutter. Referring to Fig. 3, it will be observed that when the shutter opens, the finger 138 of the front rock shaft 44 of the shutter passes the dog 137, said dog moving to permit such passa e, but when the shutter returns to its close osition, the finger 138 striking the dog 13% will cause a slight elevation of the arm 135 of the bell crank 129. This movement will effect a forward movement of the upright arm 131 of said bell crank 129 sufficient to release the finger 134 from its seat 133. The elevating springs 88 of the pressure back will consequently have sufficient force to raise said'pressure back and force the latch 135 rearwardly. The parts are now in their normal or first position. All that is necessary to again place the machine in operation is to remove the printed sheet, place a new sheet in position, and depress the lever 92, whereupon the action above described will be repeated.

The mechanism as thus far described is entirely operative for any predetermined time, but in order to vary the time of exposure, the following simple but entirely eifective and accurate mechanism is' employed. A swinging cylinder member 139 has a gudgeon 140 journaled in the lower end of the hanger 58, and a piston 141 operating in the cylinder member, is. provided with a rod 142 that has a crank connection 143 with an arm 144 projecting from the opposite side of the shaft 59. The piston is preferably provided with a series of annular dirt collecting grooves 145, and a packing ring 146. An inlet 147 through the lower portion of the piston, is controlled byan inwardly opening check valve 148 and an exhaust channel 149 extends through the gudgeon 140 of the cylinder member. The outer end of said gudgeon terminates in a nipple 150, and an exhaust conduit 151, connected to the nipple 150, is connected to a depending nipple 152 formed on a valve casing 153. This casing, as shown in Figs. 12, 13 and 14, preferably constitutes an integral part of a dial plate 154, secured upon the top 23, and having a scale 155 on its mar ginal portion. The exhaust conducting nipple 152 has a bore 156 therethrough that is in communication with a channel 157. This channel is formed in the bottom of the easing 153, and as shown in Fig. 14, is disposed eccentrically to the axis of the casing, and is tapered. The casing furtheranore is provided in its inside lower corner with an annular channel 158- from which leads an exhaust port 159. The-casing has a central upstanding stem 160 on which is journaled a rotatable valve 161. The valve, as shown in Figs. 13 and 14, is rovided in its under side with a tapered ciannel 162, which channel rides over the channel 157,

and is in communication with the annular channel 158. A cap 163 is threaded upon the upper end of the top or stem 160, and a s ring 164 interposed between the cap and va ve serves to hold the latter to its seat. The articular construction of the valve is note aimed in this lication, as it forms the subject-matter of a co-pending case. An outstanding pointer 165, connected to the valve 161 and formin an integral part thereof, operates over t e scale 155, and is preferably rovided with a handle knob 166. It wil be evident that by turning the pointer 165 the valve 161 Wlll be turned and difierent cross sectional areas of the channel 162 in the under side of said valve, will be brought into register with different cross sectional areas of the channel 157 of the valve casing or seat. Thus the area or size of the exhaust can be varied to vary the amount of air or fluid permitted to escape in a predetermined time from the cylinder member 139.

With this mechanism, it will be evident that when the motor and shaft 59 are moved to their set position by the operation of the pressure back, the piston 141, as shown in Fig. 6, will be moved to the outer end of the cylinder member 139, air being thus drawn into the cylinder member through the inlet 147. When the

springs

67 and 74 react to open the shutter and hold itopen, the speed of movement of the shaft 59 is limited by the speed at which the piston 141 can return to the inner end of the cylinder member. The speed of this piston is determined, as will be evident, by the position of the rotary valve 161 and the scale and pointer are so arranged that such speed can be readily determined. For instance, if the pointer 165 is set over the numeral 1 of the scale, the exhaust from the cylinder will take place wit-h sufl'icient rapidity to permit the motor tooperate so as to hold the shutter open one second. The length of exposure in the present embodiment can thus be varied from one to fifteen seconds. It may occur, however, that a very dense negative will require a much greater ex osure and mechanism is therefore employed for holding the shutter open an indefinite period. This mechanism includes in its make-up, a counter or register, which need not be herein specifically described, inasmuch as it con stitutes the subject-matter of a Pat-ent No. 888,667, dated May 26, 1908. Sufiice it to state that it consists of a number wheel 167, and another number wheel 168, the former being operated upon every movement of the shutter to register the number of prints made and having twelve numbers thereon, which are exposed through the dial plate 154. The other wheel 168, designates the number of dozens of rints made, and is therefore operated one increment upon each revolution of the wheel 167. The operatin means for the register comprises a swinging arm 167 having a do 167 that engages teeth 167 on the rim 0 the wheel 167 A link 168, connected to the swingin arm, is also connected to one of the cran disks 46 (see Figs. 2, 4 and 16 Thus upon every opening movement 0 the shutter, whether operated by the automatic means or the manual means, the register will be operated. It often occurs, however, that the shutter is opened when no print is made, and this opening movement is secured 'by the lever 54. It therefore is important to make the register mechanism inoperative and to accomplish this, a sliding stop plate 169 is mounted on the dial .plate, and 1S movable into the path of movement of the lever 54. This plate therefore when in operative position, limits the movement of the lever 54:. Therefore while said lever will open the shutter it will prohibit the movement of the rock shaft 44 a sufficient distance to carry the dog of the arm ast a tooth. Consequently said dog wi ride u and down upon the tooth and will not e ect-the oper-' ation of the registering mechanism. A

swinging latch 169, pivoted between the ends to a bracket 170 that depends from the dial plate 154, has a lower hooked end that is movable into and out of the path of move-' ment of the arm 167. A plunger stem 171 has one end connected to the upper end of the latch 169, while its other end slidably passes through the valve casing 153, and

bears against the periphery of the rotaryvalve 161. It is urged a amst the same by a suitable spring 172 an the periphery of the valve is provided at one oint with a notch or recess seat 173 to receive the adja-" cent end of the stem. When therefore this notch is alined with the inner end of the stem, said end will be seated therein, as shown in Fig. 13, whereupon thelatch 169 will be dis osed in the path of movement of the arm 16?. The notch, is so arranged that it will be thus alined when the ointer 165 is over the letter T on the dial p ate 154, as

- the shutter arm 63 is released from the cam track, it cannot close, inasmuch as the arm 167 cannot move downwardly. An exposure of any desired length may thus be made,

scribed. Furthermore after having ascertained the proper length of an exposure, he has only to set the machine for the period, and 'can make any number of prints from the negative without the necessity of paying close attention to the time of each exposure. Moreover the exposure operating means is automatic in its nature, and all that an operator has to do is to properly place the paper on the negative and clamp it whereupon the exposure is automatically made, and the paper automatically released. The mechanism disclosed has proven to be entirely accurate after the ffilSt adjustment of theparts is secured. This adjustment may be readily made by varying the tension of the spring 67 which, as already described, is obtained by turning the wheel 69 and looking it in its difierent positions. A further advantage of some moment is" the mounting of the entire mechanism upon the top of the casing. It is thus readily accessible, that upon theupper face being always exposed, and the remainder which is mounted on the under face being exposed when the cover or top is swung to open position. The re istering mechanism automatically operate as understood that various changes in the size,

shape, proportion, and minor details of construction, may be resorted to without departing from the spirit or sacrificing any of the advantages of the herein described invention.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is 2- 1. In a printing machine of the character set forth, the combination with negative holding means, of means for admitting light thereto, a mechanism operatively connected with the negative holding means to be automatically set into operation thereby for controlling the light-admitting means and including separate elements both active only during the opening of the light-admitting means and after which only one element operates during the exposure to hold said means open, and adjustable means for. de-

termining the period during which the single element operates on the light-admitting means to produce exposures of different lengths.

2. In a printing machine of the character set forth, the combination of negative 'holdingmeans, means for controlling the admission of lightthereto, a motor device including a plurality of elements operating together to open by their combined power the last -mentioned means and one operating longer than the other to hold the lightadmitting means open during an exposure, and an adjustable retarding device against which only the longer acting element operates during the period of admit-ting light for each exposure.

3. I11 a printing machine of the character set forth, the combination of negative holding means, a light controlling shutter associated therewith, separate motor elements operatively connected with the negative holding means to be simultaneously set thereby and operating together for opening the shutter, means for ahtomatically throw} ing one of the elements out of opcrat-idn as soon as the shutter is fully opened. and an adjustable retarding device operating against the other motor elementduring the period of an exposure. I

et. In a printing machine of the character set forth, the combination of a negativeholding means, a light-controlling shutter, an

oscillatory device, a member connected with the shutter to coact with the devlce for opening the shutter during the initial movement of the device and for holding the shntter open thereafter for the whole period of an.

exposure, and a motor means having greater power at the beginning of its movement to effect the opening of the shutter and less power after the opening of the shutter for maintaining the latter open during an exposure.

5. In a printing machine of the character set forth, the combination of a light-controlling shutter, a negative-holding means, a motor device controlling the shutter, means for setting the motor device by the operation of the negative-holding means, means for automatically reducing the power of the motor device after the latter has-opened the shutter, and a controllable retarding mechanism for varying the period of action of the motor device and thereby the length of an exposure.

6. I11 a printing machine of the character set forth, the combination of a light-controllingshutter, a negative-holding means, a motor device controlling the shutter, means for setting the motor device by the operation of holding means,

the negative-holding means, means for automatically reducing the power of the motor device after the latter has opened the shutter, a controllable retarding mechanism for varying the period of action of the motor device and thereby the length of an exposure, and a. latch mechanism for retaining the negative-holding means in operative position during the exposure and for releasing said means upon the closing of the shutter.

7. In a printing machine of the character set forth, the combination with negative holding means, of paper holding means movable to and from an operative position with respect to the negative holding means, a light cont-rolling shutter, a motor operatively connected with the shutter and having, a fixed range of movement, the first part of which opens the shntterandthe remaining part holds the shutter open to admit light to the negative holding means, and means operating with the paper holding means; to move the motor to a set position when the paper holding means moves to its operative position and while the shutter is in closed position, said means releasing the motor to permit it to open the shutter when the paper holding means reaches its said operatiw position. i

8. In aprinting machine of the character set forth, the combination with negative holding means, of a light controlling device, a'motor movable from a set position to open the light controlling device and returnable to said set position, paper holding means movable to an operative position with respect to the negative holding means,and mechanism automatically operated on the movement of the paper holding means toward said operative position to move the motor to its set position and immediately release, the motor when said paper holding means reaches its operative position for opening the said device. v

9. In a printing machine of the character set forth, the combination with negative of a movable light controlling shutter cooperating therewith, a motor for opening the shutter, movable paper holding means, and mechanism for automatically setting the motor in operation upon the movement of the paper holding means to aposition over the negative holding means.

10. In a machine of. the character set forth, the combination of a negative-holdin means, a light-controllingshutter, a roe: shaft, a cam carried thereby, a member on the shutter over which the cam rides in both directions, the length of the cam being less than the arc of movement thereof to move past the said member, the member being yieldingly connected with the shutter to prevent movement of the latter as the cam moves in one direction, and a motor device for actuating the cam in the direction for opening the shutter through the said member.

11.- In a'machine of the character set forth, the combinatipn of anegative-holding means, a light-controlling shutter, a rock shaft, a cam carried thereby, a member on the shutter over which the cam rides in both directions, the length of the cam being less than the arc of movement thereof to move past the said member, the member being yieldingly connected with the shutter to prevent movement of the latter as the cam moves in one direction, a motor device for actuating the cam in the direction for opening the shutter through the said member, and an adjustable retarding device for prolonging orshortening the period ofaction of the device.

12. In a machine of the character set forth, the combination of a swinging lightcontrolling shutter, a rock shaft, an arm having a lost motion connection with the shutter, a cam mounted on the rock shaft,

a motor for turning the rock shaft in a di rection to open the shutter through the cam and arm, means for moving the device and simultaneously re-setting the motor, the device swinging the arm without moving the shutter during the re-setting movement, and a retarding means for the motor includin a movable element operatively connecte with the cam, and also including a device for varying the rate of movement of the retarding means.

A 13. In a printing machine of-the character set forth, the combination with a negativeholding device, a light-controlling shutter, a rock shaft, a cam rotating with the rock shaft, a swinging arm actuated by the cam in opposite directions, means for connecting the arm with the shutter to move therewith when the latter swings in only one direction, a spring connected with the rock shaft, a pressure back, a device connecting the pressure back with the shaft for tensioning the spring and including means for automatically releasing the shaft at the instant the pressure back reaches its final position, a latch mechanism for holding the pressure back in operative position, and means movable with the shutter for releasing the latch at the end of an exposure;

14. In a printing machine, the combination of a pressure back, a negative-holding means cooperating therewith, means for mounting the pressure back for swinging movement, a lever yieldingly connected with the pressure back, a standard on which the lever rises and falls during the opening and closing of the pressure back, a light controlling means, a motor therefor, a connection between the said movable end of the lever and motor for re-setting the same and automatically released when the lever i reaches the end of its upward movement to permit the motor to act, and an automatically released latch device for holding the pressure back in operative position.

15. In a printing machine, the combinationof a ne ative holder, 8. pressure back composed o hingedly-connected sections, means for mounting the pressure back to swing open and closgi, means tending to open the pressure back, a lever exten ing across the pressure back and including telescopin sections, tensioning means between one o the lever sections and both of the pressure back sect-ions, a member on which one end of the lever slides, a light'controlling means rendered operative by the movement of the lever in a direction to close the pressure back, and a latch mechanism automatically released when the light is cut off to permit the pressure back to open.

16. In a printing machine, the combination of a negative holder, a pressure back composed of hingedly-connected sections, means for mounting the pressure back to swing open and closed, means tending to open the pressure back, a lever extending l across the pressure back and including telescoping sections, tensioning means between one of the lever sections and both of the pressure back sections, a member on which one end of the lever slides, a light-controlling-means rendered operative by the movement of the lever in a direction to close the pressure back, a latch mechanism automatically released when the light is cut off to I ermit the pressure back to open, and a shock absorbing and motion-retarding device oarried by the lever for gradually stopback.

17 In a printing machine, the combination of a negative holder, a pressure back composed ofhingedly-connected sections, a lever extendin across the sections and composed of sli ably connected telesco ing parts, connecting means between one o the parts and both pressure back sections and each including spring-pressed slidably conping the opening movement of the pressure 7 I nected elements, means for rigidly securing one of the connecting means to the lever,

, the other connecting means being slidably attached to said lever, a shiftablefulcrum for the lever, and a light-controlling means actuated by the lever.

! 18. In a printing machine of the character set forth, the combination with negative holding means, of light controlling means, and mechanism for operating the light controlling means, said mechanism comprising I a shaft, a spring coiled about the shaft 1 and having one end connected thereto for rotating the same in one direction, and mechanism for rotating the shaft against the tension of the sprin said mechanism in- ,detachably connecting the latter, and shaft,

and means for automatically operating the dog to release the shaft when said dog reaches a predetermined position.

19. In a printing machine, the combination of a negative holder, a pressure back composed of hingedly connected sections, a hinge for mounting the pressure back to swing as a whole, a lever extending across the axis on which the pressure back swings, a support forming a shiftable fulcrum for the lever, yielding connections between the lever and the sections of the pressure back, a light controlling means, amotor, means for connecting the motor with the fulcrumed end of the lever to re-set the motor when the lever is moved in one direction, and means for automatically releasing the lever from the motor to permit the latter to actuate the light-controlling means.

20. In a printing machine of the character set forth, the combination with coopen ating negative and paper holding means, of-

a light controlling device associated therewith, a rock shaft, means connected to the rock shaft for operating thelight controlling device, a motor connected to the rock shaft while the light controlling device is closed, and ineans for rotatingthe rock shaft in one direction to wind the motor and per-' mit it to operate and rotate the rock shaft in an opposite direction to open and hold open said light controlling means during an exposure.

21. In a printing machine of the character set forth, the combination with cooperating negative and paper holding means, of a light controlling device associated therewith, a rock shaft, means connected to the rock shaft for operating the light controlling-device, a motor connected to the rock shaft, means detachably engaging with the rock shaft for rotating the same in one di rection to wind the motor, and means for detaching the rock shaft from said rotating -1neans before beginning an exposure to permit the rock shaft to operate in an opposite direction to actuate the light controlling device.

22. In a printing machine of the character set forth, the combination with cooperating negative and paper holding means, of a light controlling device associated therewith, a rock shaft, means connected to the rock shaft for operating the light controlling device, a spring connected to the rock shaft, means for rotating the shaft againstthe action of the spring to place tension thereon, said means including a detachable dog, and means for detaching the dog before shaft reaches a predetermined position to permit. the spring to react and reverse the rock shaft to actuate the light controlling device.

28. In a printing machine, the combina-Q tion of a negative holder, a ressure back, a lever yieldin ly connected with the back and havinga fu crum at one end which moves within fixed limits during the swinging of the lever, a cable releasably connected with the said fulcrumed end, a light-controlling means, a motor movable automaticall in one direction to open the light-contro ling means, and means for positively connecting the cable with the motor to energize the latter when the lever moves to 010% the pressure back, said cable being released automatically when the pressure back reaches its final position to permit the motor to operate.

24. In a printing machine, the combination of a negative holder, a pressure back, a spring for raising the same to open position, a lever operatively connected with the pressure back to move therewith under the pressure of the spring, a fixed standard on which one end of the lever rises and falls and tilts, a flexible element, a spring connecting one end of the element with the said end of the lever, an oscillatory carrier connected with the opposite end of the element, a dog pivoted on the carrier, 2. motor,

means for engaging the dog with the motor for setting the same, a fixed stopfor releasing the dog when the carrier reaches the end of its movement'in one direction to permit the motor to act, and a shutter device actuated by the motor.

2-5. In a printing machine of the character set forth, the combination with negative holding means, of a paper holder movable to an inoperative position and an operative position with respect to the negative holding means, light controlling means, a motor for operating the light controlling means, said motor being movable to and from a set position, means for connecting the paper holder and motor including a dog, automatic means for operating the dog to connect the paper holder and motor when said paper holder reaches the end of its movement from operative to inoperative position, and means for automatically operating the dog to release the motor from the paper holder when the latter is inits operative position.

26. In a printing machine of the character set forth, the combination with negative holding means, of light controllin means, a swinging pressure back, a shaft for operating the light controlling means, a coiled spring connected to the shaft, an oscillatory carrier device having a connection with the pressure back, a dog ivoted on the carrier device and having a etachable engagement an. exposure begins and at a time when the l with the shaft to rotate the same against the spring upon the movement of the pressure back to closed position, means for engaging the dog with the shaft when the two are in a predetermined position by the pressure bacr reaching the end of its opening movement, and means for releasing the dog from the shaft when the pressure back moved in one direction.

27. In a printing machine of the character set forth, the combination with negative holding means, of a swinging pressure-back coacting therewith, light controlling means, a shaft for actuating the light controlling means, a spring coiled upon the shaft and connected thereto, means for varying the tension of the spring, a rotatable carrier device loose on the shaft, a shouldered element fixed to the. shaft, a dog pivoted on the carrier device and movable therewith into and out of engagement with the shoulder of the element, a spring for moving the carrier device in one direction, a cable connection between the swinging pressure back and carrier device, a spring for urging the dog into engagement with said shoulder, and means for disengaging the dog from the shoulder when the pressure back is moved into cooperation with the negative holding means.

28. In a printing machine of the character set forth, the combination with negative holding means, of a light controlling shutter cooperating therewith, an oscillatory actuating device movable from set position for opening the shutter, means for permitting the movement of the device in one direction to set position without actuating the shutter and effecting the actuation of said shutter on the movement of the device in an opposite direction, a motor for moving the actuating device from set position and mechanism for moving the device in an opposite direction and against the action of the motor.

29. In a printing machine of the character set forth, the combination with negative holding means, of a light controlling shutter cooperating therewith and having an arm, an oscillatory cam track that engages the arm to move the shutter, automatic means for moving the track in one direction to swing the arm and operate the shutter, and mechanism for moving the track in an opposite direction without moving said shutter.

30. In a printingmachine of the character set forth, the combination with negative holding means, of a swinging shutter cooperating therewith, an arm carried by the shutter, an oscillatory cam track that operates against the arm, a spring for moving the cam track in one direction to swing the shutter to open position and hold it open, mechanism for moving the cam track against the action of the spring, and means for releasing the'cam track and spring from said mechanism.

31. In a printing machine of the character set forth, the combination with negative holding means, of a. swinging shutter cooperatlng therewith, an arm carried by-the shutter and having a limited movement with;

respect thereto. a shaft, a cam track fixed to the shaft and operating against the arm, a spring connected to the shaft for rotating it in one direction, a pressure back, means dotachably connecting the pressure back and shaft for rotating it against the action of the spring, and means for releasing the shaft from the pressure back to permit its actuation by the spring.

32. In a printing machine of the character set forth, the combination with negative holding means, of movable light controlling means, a principal motor for moving the light controlling means and holding it in a predetermined osition, and an auxiliary motor for assisting the initial movement of the light controlling means.

In a printing machine of the character set forth, the combination with negative holding means, of a movable shutter cooperating therewith, yielding means for normally holding the shutter closed, a principal motor for moving the shutter to and holding it in open position, an auxiliary motor for assisting in the opening move ment of the shutter, and a stop for arresting the auxiliary motor prior to the stoppage of the principal motor.

3-}. In a printing machine of the character set forth, the combination with negative holding means, of a swinging shutter cooperating therewith and having an arm, a cam track engaging the arm for swinging the shutter to and holding it in open position, a principal spring motor for moving the cam track, an auxiliary spring for assisting in the initial movement of the cam track, means for stopping the auxiliary spring when the shutter is opened, and mechanism for throwing the principal spring and auxiliary spring into action.

35. In a printing machine, the combination of a swinging shutter, a negative holder, a pressure back, an adjustable latch carried by the pressure back, a swinging member engaging the latch, a spring-for yieldingly holding the member in engaging position, a lock for releasably holding the member against movement and held in locked position by the said spring, and a device operated by the shutter for releasing the lock.

36. In a printing machine, the combination of a pressure back carrying lever, an adjustable latch on the free end thereof, moans tending to move the lever in a direction to open the pressure back, a member automatically engaged with the latch to hold the lever in operative position, a bell crank lever having means for preventing movement of the said member, and a shutter having a pro- ,movementvof the shutter, means tendin jectin portion movable out of engagement with t ebell crank lever as the shutter opens and adapted to strike the lever on the returning movement of the shutter to successively release the bell crank from the member and the member from the latch,

37. In a printing machine, the combination of a casing including a source of light and having an opening, a movable negative holder in the opening, a pressure back mounted on the casing to swing to one side of the opening, a lever extending across the pressureback and mounted on the casing, tensioning devices between the lever and pressure back, a latch on the free end of the lever, a shutter movably mounted under the negative holder, and a mechanism mounted on and niovable with the negative holder for interlocking with the latch to hold the pressure back down and automatically released by the movement of the shutter.

'38. In a printing-machine, the combination of a casing including a source of light and having an opening, a movable negative holder in the opening, a pressure back mounted on the casing to swing'to one side of the opening, a lever extending across the pressure back and mounted on the casing, tensioning devices between the lever and pressure back, a latch on the free end of the lever, a shutter movably mounted under the negative holder, a mechanism mounted on and movable with the negative holder, for interlocking with the latch :to hold the pressure back down and automatically released by the to move the negative holder out of the openmg a latch for holding the negative holder in normal position, and a device associated with the negative holder and disposed be tween the latterand shutter for constituting vignette holding means.

39. In a printing machine, the combination of a casing having an opening, guides within the casing, a box-like structure movable on the guides and normally flush with the top of the casing, a negative holder carried by the structure, shutters vdisposed un der the structure, shutter-operating means mounted in the fixed part of the casing, a latch mechanism mounted on the structure, and a ressure back mounted on the casing and he (1 in locked position on the structure by the latch mechanism.

40. In a printmg machine, the combination of a casing having an opening, guides within the casing, a box-like structure movable on the guides and normally flush with the top of the casing, a negative holder carried by the structure, shutters disposed under the structure, shutter-operating means mounted in the fixed part of the casing, a latch mechanism mounted on the structure, a pressure, back mounted on the casing and held in locked position on the structure by the latch mechanism, springs tending to project the structure out of the casing, and means for releasably holding the structure in normal position.

4.1. In a printing machine, the-combination of a casing having an opening, guides within the casin a box-like structure movable on the gui es and normally flush with the top of the casing, a negative holder carried by the structure, shutters disposed under the structure, shutteroperating means mounted in the fixed part of the casing, a latch mechanism mounted on the structure, and a pressure back mounted on the casing and held in locked position on the structure by the latch mechanism, said structure belng open at one side and having a plurality of grooves for receiving vignettes.

42. In a printing machine of the character set forth, the combination with negative holding means, of a movable shutter cooperating therewith, means for moving the shutter to open position and holding it open, a motor for actuating said means to thus actuate and hold the shutter, and a variable speed governor for resisting the movement of the motor.

43 In a printing machine, the combination of a pair of oppositely-swinging shutters, a spring tending to'close the shutters, cranks on the shutters, a link connected with the cranks for moving the shutters simultaneously, a pinion connected with one of the shutters, ahandle including a sector meshingwith the pinion for manually operating the shutters, an automatic motor mechanism operatively related with the shutters, and means for controlling the mechanism for holding the shutters open during different periods.

4A. The combination of simultaneouslymovable shutters, rock shafts to which they are rigidly connected, a swinging arm, a lost motion connection between the arm and rock shaft, :1 springconnected with the arm for holding the same in a predetermined position, means for connecting the rock shafts to move together, and a device for manually moving the rock shafts for opening and closing the shutters independently of the movement of said arm. I

45. The combination of oppositely-movable shutters, a closing motor therefor, cranks connected with the shutters, a link connected withboth cranks, an automati- .pendently of the said mechanism for opening the shutters.

46. The combinationof oppositely-movable shutters, a closing motor therefor, cranks connected with the shutters, a link connected with both cranks, an automatically-actuated mechanism for opening both shutters and releasable therefrom automatically to permit the closing motor to act, a imumally-actuated device operating in opposition to the closing motor and independently of the said mechanism for opening the shutters, a negative holder, a pressure back, a latch mechanism for holding the pressure back in operative position, and means movable with one of the shutters for releasing the latch mechanism at the end of the closing movement of the shutters.

47. In a printing machine, the combination of a casing, a box-like structure mounted therein and forming a carrier, oppositelyswinging shutters, a negative holder spaced from the shutters, vignette holding means between the negative holder and shutters and mounted on the carrier, a pressure back, means for opening the shutters and operatively related with the pressure back, and a mechanism disposed between the shutters and pressure back for automatically releasing the latter by the movement of the shutters.

48. The combination of a negative holder, light controlling means, a motor therefor, a fluid-controlled retard device, a manually actuated controller therefor for varying the duration of the exposures, and means thrown into and out of operation by the controller for prolonging the length of the exposure beyond the range of the retarding means.

49. In a printing machine, the combination of a shutter, a motor for moving the same, a retarding device 'for the motor, means for varying the action of the retard ing device, and a latch mechanism thrown into or out of operation by the said means for prolonging an exposure beyond the range of the retarding device.

50. In a printing machine, the combination of a shutter, a motor .for opening the same, a fluid retarding device for the motor, a valve for controlling the device and including a rotatable element, a lock for automatically lockingthe shutter open for long exposures, and means for releasing the lock by the rotation of the valve.

In a printing machine, the combination of a shutter, a single device for opening the shutter and holding it open. during an exposure and finally releasing it after the exposure, a motor for the device, and means for completely re-setting the motor before the opening of the shutter and automatically releasing themotor at the final part of the resetting movement.

In a printing machine, the combination of a swinging shutter, a spring motor for opening the same, a controllable retarding device for the motor, and means for energizing the motor for each opening movement of theshutter, said means being movable in one direction to first resetthe motor, and finally release the same before the shutter starts to open for suddenly opening the shutter by the return movement of the motor and maintaining the shutter releasably in open osition.

' 53. In a printing machine, the combination of a swinging self closing shutter, a sprin motor for opening the same, a controlla le retarding device for the motor, means for energizing the motor for each opening movement of the shutter, said means being movable in one direction to first reset the motor, and finally release the same before the shutter starts to open for suddenly opening the shutter by the return movement of the motor and maintainin the shutter releasably in open position, with a pressure back, a negative holder, and a latch mechanism for the pressure back released directly by the shutter.

54. In a printing machine of the character set forth, the combination with negative holding means, of a swinging shutter cooperating therewith, a motor for operating the shutter, comprising independent springs thrown into operation simultaneously and having different periods of action,

and a shutter-actuating device operated by the springs, a pressure back having detachable connections with the motor for winding it, means for automatically releasing the motor from the pressure back, a cylinder member, and a iston member operating therein, one of said membersbeing connected to the motor, an exhaust conduit connected to the cylinder member, and a valve con trolling the exhaust conduit.

55. n a. printing machine of the character set forth, the combination with light controlling means, of a motor for moving the light controlling means, said motor being movable from and to a set position and including a plurality of springs operating conjointly to open the light-controlling means, one of the springs being automatically thrown out of operation after the opening of the said means while the other spring continua to act, means for moving the motor to its set position and releasing it to permit it to move and operate the light controlling means, a cylinder member and a piston member operating in the cylinder member, one of the members being connected to the motor to permit the inflow of fluid to the cylinder member when the motor is movedv to its set position, said cylinder member having an exhaust, and means for varying the size of the exhaust to vary the relative speed of the cylinder and piston members and thereby vary the speed of the motor. a

56. In a printing machine of the character set forth, the combination with negative holding means, of. shutter, a pressure shutter, a handle, and gearing connecting the handle and shutter, said handle constitutlng means for opening the shutter inde:

pendently of the automatic mechanism and of the pressure back.

57. In aprinting machine of the character set forth, the combination with negative holding means, of light controlling means, automatic mechanism for moving thelight controlling means to inoperative and operative positions, and manual controlling means for securing the light controlling means in one of said positions inde pendently of the position of the automatic means.

58. In a printing machine of the character set forth, the combination with negative holding means, of a movable shutter, automatic mechanism for opening and closing the shutter, and manuallycontrolled means for locking the shutter in opened position when opened by the automatic mechanism and against being closed by said automatic mechanism.

59. In a printing machine of the character set forth, the combination with negative holding means, of a shutter, automatic mechanism for moving the shutter to open position and returning it to closed position, a latch movable to a position to lock the shutter open when opened by the automatic mechanism, and manual means for moving the latch to an inoperative position.

60. In a printtng machine of the char acter set forth, the combination with negative holding means, of a shutter, a pressure back, a lock for the pressure back, automatic means controlled by the pressure back for opening the shutter, and manually operated means independently of the pressure back for locking the shutter open.

61.. In a printing machine of the character set forth, the combination with nega tive holding means, of a shutter, means for automatically opening the shutter and closing it, and manually controlled means for locking the shutter in open position when opened by said automatic mechanlsm.

62. In a printing machine of the character set forth, the combination with negative holding means, of a shutter, a pressure back," automatic means controlled by the pressure back for opening the shutter and closing the 'same, a lock for thepressure back, means for automatically operating the lock to release 't-he'pressure back when the shutter closes, and manually controlled means for'locking the shutter open when opened by said automatic means.

63. In a printing machine of the character set forth, the combination with negative holding means, of a shutter, automatic means for operating the shutter including a motor,

speed varying mechanism for the motor including a controller, and means for locking the shutter 0 on, said controller constituting an actuator or the locking means.

64. In a printing machine of the character set forth, the combination with a negative holder,of ashutter, automatic means for operating the shutter including a. motor, speed varyin mechanism for the motor including a cy inder and a piston operating therein, an exhaust conduit connected to the cylinder, a controlling valve for the exhaust conduit, and a latch movable into and'out of a position to lock the shutter in open position, said valve constituting actuating means for the latch. i

65. In a printing machine of the character set forth, the combination with a swinging pressure back, of means for swinging the same, a latch detachably engaging the pressure back and moved to an inoperative position thereby, a lock engaging the latch for holding it against such movement, and means for operating the latch.

' 66. In a printing machine of the character set forth, the combination with a swinging pressure back, of means for swinging the same, a latch detachably engaging the pressure back and moved to an inoperative position thereby, a lock engaging the latch for holding it against such movement, a movable shutter, and means operated-by the shutter for moving the latch.

67 In a printing machine of the character set .forth, the .combination with negative 100 holding means, of a swinging pressure back cooperating therewith and'having a shoulder, a latch that engages the shoulder to hold the pressure backupon the negative holding means, said latch being moved to an inoperative osition by the shoulder, a finger projecting from the latch, a lock for the latch comprising a bell crank lever, one arm of which is provided with, a seat that engages the finger to hold the latch against no movement, a swinging shutter, and means operated by the shutter and engaging the other arm of the bell crank to move said bell crank and' release the finger.

68. In a printing machine, the combination of a pressure back, a lever, slidably connected parts between the pressure back and lever, means for limiting the separating movement of the parts, a spring tending to separate the parts, a negative holder, and a latch device associated with the lever for holding the pressure back against the negative holder and under the pressure of the said spring. r

69. In a printing machine, the COIlllOIIlEl-l tion of a negative holder, a pressure back, means. for hingedly mounting the same, a movable element extending across the pressure back, said pressure back being composed of sections jointed together, a lever having a